THE

SYDENHAM SOCIETY

INSTITUTED

MDCCCXLIII

LONDON

MDCCCXLVI.

THE WORKS

OF

WILLIAM HEWSON, F.B.S.

libraries

^..r nes ra, uo ----- -

^^ jri^sorks will be both

EDITED

WITH AN INTRODUCTION AND NOTES

GEORGE GULLIVER, F.R.S.

SURGEON IN THE ROYAL REGIMENT OP HORSE GUARDS.

LONDON

PRINTED FOR THE SYDENHAM SOCIETY

MDCCCXLVI.

C. AND J. ADLARD, PRINTERS,

BARTHOLOMEW CIOSE.

K-QP6

EDITOR'S PREFACE.

ALTHOUGH Hewson's merit, as a physiologist, is generally
admitted, his writings have been unjustly neglected, and are
now so scarce that a complete copy of them is not to be found
in the stock of any London bookseller, nor even in some of
our best libraries, as that of the British Museum.

Hence a new edition of Mr. Hewson's Works will be both
an acceptable present to physiological literature and a just
tribute of respect to his memory.

His Plates, which have all been carefully engraved on this
occasion, will always be interesting. It is true that some of
them might now be displaced by others containing more exact
information in the same space ; but then historical truth would
suffer, and the conscientious inquirer would still be compelled
to consult the old copies.

In the Introduction^ an account is given of Hewson's life
and writings, with a careful survey of the facts ascertained
and opinions held concerning the blood by his predecessors
and contemporaries, followed by an estimate of the value of
his Inquiries. This course appeared necessary in justice to
the old physiologists, and well calculated to afford an interest-
ing and instructive view of the progress of research in a most
important subject, about the history of which so much error
prevails.

An attempt has been made to place the matters to which
the Notes relate on a level with the present state of know-
ledge ; while in them also the historical method has generally

£304583

g

vi EDITOR'S PREFACE.

been kept in view, because it is useful and pleasing, in a
work of this nature, to mark the footsteps of science and the
names of its cultivators.

For most generous and valuable aid in the course of his
labours, the Editor has now the grateful duty of returning his
best thanks to his friend Dr. Davy, whose elaborate Researches
have so much advanced our knowledge of the blood,

The Editor's Notes are placed beneath lines and referred
to the Text by numbers within parentheses.

CONTENTS.

PAGE

Introduction, on the Life and Writings of Hewson, with a History of the

Coagulation of the Blood .... . • xiii

List of Hewson's Writings ...... xlix

General Index 321

PART I.

PROPERTIES OF THE BLOOD.

CHAPTER I.

Of the Separation of the Serum ; the Colour of the Crassamentum ; and

of the Causes of the Coagulation of the Blood ... 1

CHAPTER II.
Of the Inflammatory Crust, or Size ..... 30

CHAPTER III.

Of the Causes of the Inflammatory Crust's appearing at different times in
Bloodletting ; of the Stopping of Hemorrhages ; and of the Effects
of Cold upon the Blood . . . . . .12

CHAPTER IV.

Some further Observations on the €oagulahle Lymph, and on the Sudden

Changes produced upon it. . . . . 53

CHAPTER V.

Containing a Recapitulation of the principal Facts and Conclusions that are

mentioned in the preceding pages . . 71

CHAPTER VI.

Of the Serum of the Blood, and particularly of the Milk-like Serum . 78

Of the White Serum 82

viii CONTENTS. .

APPENDIX.

The Discovery of the Lymphatic System in Birds, Fish, and the Animals

called Amphibious . . . . . . 91

Copy of Dr. Alexander Monro's Claim, &c., read hefore the Royal Society,

January 19, 1769 96

PART II.

•

LYMPHATIC SYSTEM.

CHAPTER I.
A short History of the Discoveries made in the Lymphatic System . 119

CHAPTER II.

A general Account of the Lymphatic System . 123

CHAPTER III.

A particular Description of the Lymphatic System in the Human Body . 128

CHAPTER IV.
A Description of the Lymphatic System in Birds 144

CHAPTER V.

A Description of the Lymphatic System in one of the Animals called Am-
phibious, viz. the Turtle ...... 147

CHAPTER VI.

The Method of Discovering the Lymphatics in Turtle and in Fish, together

with a Description of those Vessels in a Haddock . . . 151

CHAPTER VII.

On the Properties of the Lymph contained in the Lymphatic Vessels, and

of that which lubricates the different Cavities of the Body . 157

CONTENTS. ix

PAGE

CHAPTER VIII.

Of the Manner in which the Lymph is secreted into the Cavities, for their

Lubrication . •. . . . . » 16G

CHAPTER IX.

An Examination of the Opinion whether the Common Veins do the Office

of Absorption ....... 171

CHAPTER X.
On the Use of the Lymphatic System ..... 181

CHAPTER XI.

An Examination of the Opinion whether some of the Lymphatic Vessels

may not be Continuations of the Small Arteries . . . 186

CHAPTER XII.

On the Structure of the Villi of the Intestines, and the Manner in which

Absorption is performed . . . . . . 187

CHAPTER XIII.

Containing some Pathological Observations relating to the Lymphatic

System ........ 196

PART III.

RED PARTICLES OF THE BLOOD.

CHAPTER I.

On the Figure -and Composition of the Red Particles of the Blood, com-
monly called the Red Globules . . . . . 211

Tables of Measurements of the Red Corpuscles of the Blood.

Mammalia . . . . . . . 237

Aves 239

Reptilia ........ 242

Amphibia ........ ib.

Pisces ......;. 243

Measurements of the Red Corpuscles of the Blood of Postal or Immature

Animals . . . . . f . . ib.

Measurements of the Pale Corpuscles of the Blood • *. . . ib.

*

x CONTENTS.

PAGE

Measurements of the Corpuscles of the Chyle, of the Lymph, and of the

Thymus Fluid . . . ... . .-....• . 244

Measurements of the Glohules of Pus . ib.

CHAPTER II.
On the Structure of the Lymphatic Glands . . . . . 245

CHAPTER III.
On the Situation and Structure of the Thymus Gland . . 255

CHAPTER IV.
On the Situation and Structure of the Spleen .... 264

CHAPTER V,

Containing an Account of the Manner in which the Red Particles of the
Blood are formed, deduced from the Experiments and Observations
related in the preceding chapters ..... 274

DETACHED PAPERS.

A Letter from the late Mr. William Hewson, F.R.S., and Teacher of Ana-
tomy in London, to Dr. John Haygarth, Physician in Chester . 287

The Operation of the Paracentesis Thoracis, proposed for Air in the Chest,
with some Remarks on the Emphysema, and on Wounds of the
Lungs in general . . . . . . .291

Description of the Plates ....... 303

INTRODUCTION,

LIFE AND WRITINGS OF HEWSON,

WITH A HISTORY OF

THE COAGULATION OF THE BLOOD.

INTRODUCTION.

FOR the little that is known of the private life of William
Hewson, we are indebted to the affectionate care of his widow,
who left a manuscript memoir of him, which was sent by her
son, Dr. Thomas Tickell Hewson, with a letter from Phila-
delphia, dated October 28, 1804, to Dr. Lettsom, and afterwards
published in the life of this amiable physician by Mr. Pettigrew.1
There is also a short account of Mr. Hewson by Dr. Lettsom,2
compiled from Mrs. Hewson's papers. The following letter
was written by her to Dr. Samuel Foart Simmons, who pub-
lished it in his Life of Dr. Hunter.3 The letter was also partly
inserted in Dr. Hahn's Preface to the Latin edition of Hewson's
Works, by Dr. J. van de Wynpresse.4

SIR, — I should think myself bound to grant any request
introduced with Mr. Watson's name ; but that which you make
in the letter I received yesterday needed no such introduction.
A tribute paid to the memory of Mr. Hewson is highly grati-
fying to me, and I can have no employment that will give me
more satisfaction than that of assisting in any degree to the
spreading of his fame.

You say you are not unacquainted with the general history
of Mr. Hewson' s life, and you speak of him in terms which
show that you are not unacquainted with his character. Had
you been among the number of his friends, you would bear

1 Memoirs of the Life and Writings of the late John Coakley Lettsom, M.D.,
3 vols. 8vo, London, 1817.

2 Transactions of the Medical Society of London, vol. i, art. 2, 8vo, Lond. 1810.

3 An Account of the Life and Writings of the late William Hunter, M.D., p. 39,
8vo, London, 1783.

4 Guil. Hewsoni Opera Omnia, 8vo, Ludg. Batav. 1795.

xiv INTRODUCTION.

testimony to his private virtues, which rendered him no less
dear to his family and associates, than his talents made him
respectable in the world.

Mr. Hewson was born at Hexham, in Northumberland, on the
14th Nov. O.S., 1739. He received the rudiments of his
education at the grammar-school in that town under the Rev.
Mr. Brown. His father was a surgeon and apothecary in the
place, and much respected in that neighbourhood. With him
Mr. Hewson acquired his first medical knowledge. Being ambi-
tious to increase that knowledge, he placed himself first under
an eminent surgeon in Newcastle, Mr. Lambert, and afterwards
resided some time at London, Edinburgh, and Paris. His
subsequent acquirements are sufficient to prove that he visited
those places with a true love of science and desire of attaining
eminence in his profession.

I became acquainted with him in the year 1768. He was
at that time in partnership with Dr. Hunter. Some similarity
in our dispositions created a mutual esteem, and the equality
of our situations made our union desirable in point of prudence.
I had five months the start of him in age, no pretensions to
beauty, nor any splendid fortune ; yet I believe he was satisfied
with the choice he made. We were married July 10, 1770.
I brought him two sons. The elder was just three years old
when Mr. Hewson died, which was on the 1st of May, 1774,
and I was delivered of a daughter on the 9th of August follow-
ing. His last moments of recollection were embittered by the
idea of leaving me with three children scantily provided for.
The trial of my fortitude was different ; the loss of affluence I
did not feel for myself, and I thought I could bring up my
children not to want it. However, by the death of an aunt,
who left me her fortune, I became reinstated in easy circum-
stances, and am enabled to give a liberal education to my
children, who I hope will prove worthy of the stock from which
they grew, and do honour to the name of Hewson.

Mr. Hewson' s mother is still living at Hexham, and has one
daughter, the youngest and only remaining child of eleven.

His father died in 1767; and having had so large a family, it
will be readily supposed he could not give much to his son, so
that Mr. Hewson's advancement in life was owing to his own
industrv.

INTRODUCTION. xv

A better son and husband, or a fonder father than Mr.
Hewson never existed. He was honoured with the friendship
of many respectable persons, now living, and the late Sir John
Pringle showed him singular marks of regard.

Mr. Hewson' s manners were gentle and engaging; his
ambition was free from ostentation, his prudence was without
meanness, and he was more covetous of fame than of fortune.

You will, I trust, readily forgive me, if I have been more
prolix than you desired. It would be no easy matter to relate
bare facts without some comment on such a subject.

I am, Sir, your most obedient humble servant,

MARY HEWSON.

Kensington, Aug. 30, 1782.

Mr. Hewson' s mother, whose maiden name was Heron, was
a native of Hexham, and allied to several respectable families
in that town. She had eleven children, of whom he and three
daughters only remained in 1767, when his father died.

In the autumn of 1759 Mr. Hewson came to London,
lodged with Mr. John Hunter, and attended Dr. William
Hunter's Anatomical Lectures at a house in Covent Garden.
Hewson's diligence and skill soon recommended him to the
favorable notice of the brothers ; and when Mr. Hunter went
abroad with the army, early in 1761, he left to Mr. Hewson the
charge of instructing the other pupils in the dissecting-room, by
which means, as Mrs. Hewson remarks, he gained money at an
age when most students in surgery are only spending it.

He entered himself a pupil at Guy's and St. Thomas's
Hospitals ; and attended Dr. Colin Mackenzie on midwifery,
and Dr. Hugh Smith on physic. In gratitude to the liberal
confidence of his father, Hewson was justly careful of his
money, and this prudence continued through life, though not
so as to check the growth of generosity; for no man ever
exercised his profession with less avidity of gain ; he disdained
every species of meanness, and possessed a judicious liberality
which elevated his character. His father had the happiness
of living to reap the fruit of this care.

Mr. Hewson took with him recommendatory letters from
Dr. Hunter and Sir John Pringle to the professors at Edinburgh,
and studied there until the winter of 1762, when he returned

xri INTRODUCTION.

to London/ entered into partnership with Dr. Hunter, gave
some of the lectures, and had a share of the profits. Their
anatomical school was in Litchfield street, where Mr. Hewson
lived, and took some of the pupils to board with him.

In the summer of 1765 Mr. Hewson went to France, and
returning through Flanders and Holland, arrived in London
in time for the anatomical lectures.

He went to the sea-coast of Sussex in the summer of 1768
to make experiments upon fish. His papers on the lymphatic
system of oviparous vertebrate animals were laid before the
Royal Society during the following winter, when he was made
a Fellow of that body. The date of his election was March 8,
1770.1 To his recommendatory certificate, read December 7,
1769, and preserved in the archives of the Royal Society, eleven
signatures were affixed, among which may be noticed, John
Pringle, William Hunter, B. Franklin, M. Maty, J. Turton,
and James Ferguson.

In 1769 Dr. Hunter finished his building in Windmill
street, where Hewson had a small apartment allotted to him.
They continued the lectures in partnership, dividing the profits
equally, Hewson giving more of the lectures than he had
formerly done. Though he did not seek much practice in
surgery and midwifery, his manners were so engaging and he
showed so much skill, that the profits of these branches of his
business were not inconsiderable.

The Windmill-street School no longer exists ; but it will be
preserved from oblivion by the names of the eminent men who
lectured there. Among these the future historian of anatomy
and physiology in England will have to commemorate William
Hunter, Hewson, Cruikshank, Sheldon, Baillie, Brodie, Charles
Bell.

Hewson, soon after his marriage in 1770, took a house near
Dr. Hunter, and they continued the lectures together during
the winter of 1771. The partnership was soon afterwards dis-
solved ; and Mr. Hewson began to lecture on his own account,
September 30, 17 72, in Craven street, where he had built a theatre
adjoining a house which he intended for the future residence
of his family. Before he began this course of anatomy, he

1 Journal Book of the Royal Society, fol. MS. vol. xxvii, p. 321.

INTRODUCTION. xvii

gave a lecture, to which he invited many men of science, on
the uses of the spleen and thymus. He commenced his lectures
with great applause, and before the end of the course succeeded
so well, that he had more than half the number of pupils that
he and Dr. Hunter had when in partnership. Mr. Hewson's
second course of lectures, as well as those which he delivered
during the winter of the following year, were quite as suc-
cessful.

From the manner in which Dr. Hunter1 and Mr. Hewson3
wrote of each other, it is pleasing to suppose that they did not
finally retain any acrimonious feeling from the disagreement
which had led to their separation. This subject may be dis-
missed with the following letter by Dr. Franklin, for which I
am indebted to the kindness of Mr. Hunter Baillie, who gave
me the copy from the original in his rich collection of autograph
letters, many of which, as is probably the case with the present
one, have not been published.

To Dr. William Hunter.

Craven Street, Oct. 30, 1772.

SIR, — I should sooner have answered your questions, but,
that in the confusion of my papers, occasioned by removing to
another house, I could not readily find the memorandums I
had made during the unpleasant time in which as a common
friend I was obliged to hear your and Mr. Hewson's mutual
complaints. I have now found one of those memorandums,
dated Aug. 23, 1771, the same which I afterwards read to you,
containing your idea as then expressed of the terms on which
you were to proceed together. The following is an extract
from it : " Dr. Hunter expects Mr. Hewson should go on with
his business as usual, during the remainder of the term they
are to continue together ; and during that time should make
preparations at Dr. Hunter's expense, such as the Dr. should
direct to be made, and others, so that those directed are not
neglected or omitted ; that as the preparations are to be the
Doctor's sole property, and at his absolute disposal, so that

1 Introductory Lectures to his last Course of Anatomy, p. 60, 4to, Lond. 1784.

2 On the Lymphatic System, p. 166 of this volume.

xviii INTRODUCTION.

if he afterwards should give any of them to any person (which
he could not be understood to promise) such gift is to he
considered as the sole effect of his good-will." Some time last
summer, after your parting, you wrote me a note, which I
cannot at present find, but I think the purport of it was that
you had some preparations which you could spare, and were
disposed to give me, desiring I would call and look at them ; I
did so and accepted them ; I apprehended it to be your suppo-
sition in giving them to me, that as I had no use for them, I
should probably give them to Mr. Hewson, which I immediately
did. Having said this, I must add, in justice likewise to Mr.
Hewson, that his conception of the original agreement between
you was that he had a right to make such preparations for
himself, your business and the common interest of the partner-
ship not being neglected. Here you had differed in opinion ;
but came to a kind of compromise expressed in a paper that I
handed between you, a copy of which I have obtained from
Mr. Hewson to send you.

I am, Sir, your most obedient and most humble servant,

B. FRANKLIN.

Early in 1774 Hewson had every reason to be gratified with
his position. " In viewing the situation of our associate at
this period," says Dr. Lettsom, " the most gratifying prospects
presented themselves, where genius and industry were rewarded
with success, and domestic amities with felicity. The theatre
in which he delivered his lectures and expounded his doctrines
was crowded with men of science, as well as with pupils, to
listen to a youth grown sage by experimental researches."
In short, Hewson was now surrounded by the blessings of life.
He had a kind and just wife who had borne him two lovely
sons; his favorite sister lived with him; his success in teaching
was no longer doubtful ; and his practice in surgery and mid-
wifery had so much increased as to give him the fairest prospect
of providing well for his family.

But this happiness was soon to end. He was seized with a
fever occasioned by a wound received in dissection, which proved
fatal on May-day, 1774, after a short illness, in the thirty-fifth
year of his age.

In the second volume of the ' Medical and Philosophical

INTRODUCTION.

xix

Commentaries' the following notice was inserted : " On Sunday,
May 1st, died at London, Mr. William Hewson, Fellow of the
Royal Society, and Teacher of Anatomy. From those inge-
nious publications with which he has already favored the public,
his untimely death will be regretted by every sincere lover of
science." Dr. Franklin1 wrote from Craven street on the 5th
of the same month, " Our family here is in great distress.
Poor Mrs. Hewson has lost her husband, and Mrs. Stevenson

her son-in-law He was an excellent young man,

ingenious, industrious, useful, and beloved by all that knew him.
He was just established in a profitable, growing business, with
the best prospects of bringing up his young family advan-
tageously. They were a happy couple. All their schemes of
life are now overthrown."

He was buried at St. Martin's-in-the-Fields, as appears from
the following notice in the Register, kept in the church, of
burials in that parish : " May 6, 1774, William Hewson, a
man." I know not that any monument was afterwards erected
to his memory, nor indeed that he ever had an epitaph. I
could not find his grave.

Mrs. Hewson describes him as slender in form, above the
middle stature; with a good air and a pleasing countenance,
expressive of the gentleness and sagacity of his mind. Her
face was thought to resemble his.

I have not been able to learn that there is any painting of
him. There is an indistinct representation of his bust in the
background of the pleasing picture by S. Medley, in the library
at Bolt court, of the early members of the Medical Society of
London, established in 1773, the year before Hewson' s death.
But his countenance is so little known, that the engraving of
him given in this volume will be an acceptable addition to the
portraits of British physiologists. It is from a mezzotinto in
the possession of Mr. John Quekett, probably the same as that
spoken of by Dr. Franklin, as follows, in a letter which he
wrote to Mrs. Hewson from Passy, in June, 1782 : — "I forget
whether I ever acknowledged the receipt of the prints of Mr.
Hewson. I have one of them framed in my study. I think
it very like."

1 Franklin's Works, edited by Jared Sparks, vol. viii, p. 121, 8vo, Boston, 1840.

xx INTRODUCTION.

Of a woman so exemplary as Mary Stevenson, so well worthy
to be the wife of Hewson, it is right to preserve some memorial.
This, indeed, is to be found in the affecting and excellent tribute
which she has left to his memory. But we have still better
testimony of her merits. Her second son, Dr. Thomas Tickell
Hewson, in his letter to Dr. Lettsom, dated October 28, 1804,
has described the gratitude of her children for her tenderness as
a mother. She had been upon terms of the warmest friendship
with Dr. Franklin since she was eighteen years of age. That
eminent philosopher resided with her mother, Mrs. Margaret
Stevenson, at No. 7, Craven street, Strand, during the fifteen
years of his abode in London. Miss Stevenson lived mostly
in the country with her aunt, Mrs. Tickell. When Miss
Stevenson thought of marrying Hewson she consulted Franklin,
and how highly he esteemed her may be seen by the letter,
dated May 31, 1770, which he wrote to her on that occasion.
She was also acquainted with Dr. Hawkesworth, whose grave
I have seen in the churchyard at Bromley. Writing to her
from Craven street, June 7, 1762, Franklin says, " I am glad
to hear that you are about to enjoy the happiness of seeing and
being with your friends at Bromley. My best respects to the
good Doctor and Mrs. Hawkesworth;" and again, January 9,
1765, "Your good mamma and myself are both of opinion that
the Christmas gambols at Bromley last a great deal too long."
On the 27th of January, 1783, he writes to her from Passy: " In
looking forward, twenty-five years seem a long period, but in
looking back, how short ! Could you imagine, that it is now full
a quarter of a century since we were first acquainted ? It was
in 1757. During the greatest part of the time I lived in the
house with my dear deceased friend, your mother; of course
you and I conversed with each other much and often. It is to
all our honours, that in all that time we never had among us the
smallest misunderstanding. Our friendship has been all clear
sunshine, without the least cloud in its hemisphere. Let me
conclude by saying to you, what I have had too frequent occa-
sions to say to my other remaining old friends. The fewer we
become, the more let us love one another."

She passed the winter of 1783 to 1784 with him at Passy,
where her intelligence and amiableness were particularly noticed.
Franklin had not only taken great care in the directing of her

INTRODUCTION. xxi

studies, but he addressed some of his best letters on philoso-
phical subjects to her. After she had lost her mother, in 1783,
he frequently expressed a wish that she would become his neigh-
bour in America. Accordingly, in 1786, she went with her
children to Philadelphia, where she lived until 1792, and then
removed to Bristol, in Pennsylvania, where her eldest son,
William, had established himself, and where she closed a well-
spent life on the 14th of October, 1795. Her second son,
Thomas Tickell Hewson, who was an eminent physician, and
her daughter, Mrs. Caldwell, were both living at Philadelphia
in 1837. Her son William died at Vera Cruz in 1802.1

In the hope that some further information might be obtained
from America concerning Mr. Hewson or his descendants, the
printing of this sheet has been long delayed ; but my inquiries
have only elicited that his son, Dr. Hewson, is at present the
respected President of the College of Physicians at Philadelphia.

We are now to consider Mr. Hewson's writings. In 1767
his paper on the Operation of perforating the Pleura in cases of
Air in that Sac, was communicated by Dr. Hunter and pub-
lished in the third volume of the ' Medical Observations and
Inquiries.'

The second Dr. Monro had before, in his lectures, proposed
the same operation, of which, when Hewson was informed, he
made a suitable acknowledgment to Dr. Monro, and published
it in the Appendix to the first and second editions of the
( Inquiry into the Properties of the Blood/

Hewson's three papers on the Lymphatic System in Birds,
Amphibia, and Fishes, appeared in the 'Philosophical Trans-
actions' for 1768 and 1769, and form the substance of the fourth,
fifth, and sixth chapters of the Second Part of his 'Experimental
Inquiries/ published but a short time before his death in 1774,
and dedicated to Dr. Franklin, who had shown Hewson great
regard since his marriage to Miss Stevenson. The first paper
was read before the Royal Society on the 8th of December, 1768;
and the discovery of the vessels which correspond in the lower
vertebrate animals to the lacteals of mammalia was claimed by

1 Franklin's Letters and Miscellaneous Papers, with Notes, by Jared Sparks, 12mo,
London, 1833 ; and the Works of Benjamin Franklin, with Notes and Life of the
Author, by Jared Sparks, 10 vols. 8vo, Boston, 1840.

xxii INTRODUCTION.

Dr. Monro, in a letter read before the same Society on the
19th of January, 1769, and in a separate publication.1 A bitter
controversy followed. Hewson's answer to Dr. Monro was
given in the Appendix to the first and following editions of his
* Inquiry into the Properties of the Blood/ and Dr. Monroes
rejoinder in the seventh chapter of his large work on the
f Structure and Physiology of Fishes/ eleven years after Hewson's
death.

After the supposed discovery by Dr. Hunter or Dr. Monro,
that absorption in the animal body is exclusively performed by
the lymphatic vessels, the question of the existence of these
vessels in birds, reptiles, and fishes appeared of the highest im-
portance ; and the supporters of this doctrine of absorption felt
the necessity of showing that these animals possess a lymphatic
and lacteal system, which was at that time disbelieved by many
anatomists; and even by Dr. Monro, as late as 1758.2

But the question has now lost much of its interest, because
the lymphatic vessels are no longer held to be the exclusive
agents of absorption;3 and the main point contended for by
Dr. Monro and Mr. Hewson, to wit, the honour of the first
discovery of the lacteal vessels in oviparous vertebrate animals,
does not strictly belong to either of the disputants ; for the
lacteals of a fish were observed above a century before by
Thomas Bartholin,4 though his description was alloyed with
the old error, that they terminate in the liver. It was well
remarked by Mr. Abernethy,5 that all our knowledge of the
absorbing vessels has been obtained by fragments, and that our
future acquisitions must be made in the same manner.

But whatever may be thought now of the question of dis-
covery, it must be allowed that the lymphatic system of the

1 ' A State of Facts concerning the first Proposal of performing the Paracentesis
of the Thorax, on account of Air effused from the Lungs into the Cavities of the
Pleurae ; and concerning the Discovery of the Lymphatic Valvular Absorbent System
of Vessels in Oviparous Animals, in Answer to Mr. Hewson ; by Alexander Monro,
Physician and Professor of Physic and of Anatomy in the University of Edinburgh.'
8vo, Edinb. 1770.

2 Observations, Anatomical and Physiological, p. 57, 8vo, Edinb. 1758.

3 See Note LXXXII, page 179.

4 De Lacteis Thoracicis in Homine Brutisque nuperrime Observatis, Historia Ana-
tomica, p. 70, 12mo, Lond. 1652.

5 Philosophical Transactions, 1796, p. 33.

INTRODUCTION. xxiii

lower vertebrate animals was more completely exhibited by
Hewson than by any of his predecessors or cotemporaries.

When Dr. Monroes letter, printed at page 96 of this edition,
was read before the Royal Society, there was also read a letter
from Mr. Hewson ; whereupon it was remarked by the president,
Mr. West, " that he supposed the Society would think them-
selves obliged for these, as they do for all ingenious communi-
cations ; at the same time that they would undoubtedly adhere
to the constant rule of the Society, not to interfere by giving
judgment in any matter of dispute which should be brought
before them, and may afterwards become questionable in the
learned world."1

On the 16th of November, 1769, ten months after Dr.Monro's
claim had been read, the reading of Mr. Hewson' s two papers
on the lymphatic system of amphibia and fishes was completed,
and the following notice was entered in the Journal Book of
the Society:2 "Mr. Hewson' s descriptions were greatly illus-
trated by the exhibition of a series of preparations taken from
turtles and divers fishes, wherein these vessels were injected
and shown to the naked eye in their rise, progress, communi-
cations, and insertions, to the great satisfaction of the Society.
Thanks were returned to Dr. Hunter and Mr. Hewson for these
very ingenious communications." They were communicated to
the Society by Dr. Hunter.

On the 22d of November, 1770, there was a council of the
Society, composed of no less than fifteen members, including the
president, when Sir Godfrey Copley's gold medal was awarded
by ballot to Hewson, " for his papers on the lymphatic system
in birds, amphibious animals and fishes/'3 Among the names
of members present at that council, I find the Honourable
Daines Barrington, the Honourable Henry Cavendish, Mr.
Maskelyne, Dr. Maty, and Dr. Watson.4 The medal was
delivered to Mr. Hewson at the anniversary meeting of the
Society on the 30th of the same month, when his researches
were warmly praised by the president, from whose address on
the occasion the following extracts are taken.

" The discoveries which Mr. Hewson has made are in a very

1 Journal Book of the Royal Society, fol. MS. vol. xxvii, pp. 161-3.

2 Vol. xxvii, pp. 241-44. 3 Ibid. p. 397.

4 Minutes of the Council of the Royal Society, fol. MS. vol. vi, pp. 84-5.

xxiv INTRODUCTION.

high degree interesting, not only on account of his investigation
of parts of the animal system before scarce known, not only on
account of the clear idea which his accurate descriptions and
elegant preparations have enabled us to form of the parts dis-
covered, but also that he has thereby been enabled to confirm
that hypothesis which had been, with great show of reason, en-
tertained, that the lymphatics are the only absorbent vessels.

" He has not only discovered the existence of this system in
the classes of birds and fish, but he has been enabled to follow
the course of them (the lymphatics) to an astonishing minute-
ness, and proved their beautiful disposition on the intestines to
ocular demonstration."1

It was also stated by the president, that he and the council,
in adjudging the medal to Mr. Hewson, had considered chiefly
what person had, within the year 1769, " contributed most to
the advancement of science and useful knowledge." Hewson' s
papers were highly commended by many of his contemporaries,
especially by Dr. Hunter,2 Mr. Sheldon,3 and Dr, Lettsom.4

Hewson' s three papers on the Properties of the Blood were
published in the ' Philosophical Transactions' for 1770; and
form the first three chapters of the First Part of the ' Experi-
mental Inquiries/ Before the publication of the second edition,
in 1772, of the ' Inquiry into the Properties of the Blood/ it
underwent, according to Mrs. Hewson,5 a critical examination
by Sir John Pringle, to whom it was afterwards dedicated.
The first, or duodecimo edition was published in 1771. There
is a third edition, merely a reprint, in 1 780, of the second.

His observations on the Red Particles of the Blood, which
appeared in the f Philosophical Transactions' for 1773, were re-
published by Magnus Falconar in the first chapter of the Third
Part of the ( Experimental Inquiries/ An imperfect abstract of
Hewson's Observations on the Uses of the Lymphatic Glands,
Thy mus, and Spleen, was published, without his concurrence, in the
first volume of the ' Medical and Philosophical Commentaries / 6
and in July, 1773, he gave a short account of his views on those

1 Journal Book of the Royal Society, fol. MS. vol. xxvii, pp. 396-9.

2 Two Introductory Lectures to his last Course of Anatomy, p. 60, 4to, Lond. 1784.

3 History of the Absorbent System, pp. iii, iv, 4to, London, 1784. . .

4 Transactions of the Medical Society of London, vol.i,p. 61, 8vo, Lond. 1810.

5 Mr. Pettigrew's Life of Dr. Lettsom, vol. i, p. 145.

6 By a Society in Edinburgh, 8vo, London, 1773.

INTRODUCTION.

XXV

subjects, in a letter to Dr. Hay garth, which appeared in the third
volume of the same work.

Concerning the coagulation of the blood, so admirably illus-
trated by Hewson's labours, it is remarkable that the historical
part has been strangely neglected. From this remark the in-
teresting notices by Dr. Davy1 must be excepted ; but they are
only sufficient to show, what it is probable he intended, that
further inquiry on the subject is wanted. In short, so im-
perfect are the records of this branch of science, that physio-
logical literature, overflowing about the red particles, is yet
destitute of a connected history of the spontaneously coagulable
principle of the blood. This, up to the year 1832, I shall now
attempt to supply. It will be a curious chapter in physiological
history, showing the uncertainty of fame and the slowness of
justice -, the delusion of hypothesis and the advantage of ob-
servation and induction. Such a narration is moreover abso-
lutely necessary to enable us to form a correct estimate of the
merits of Hewson, and of some of his contemporaries, as original
inquirers. He entertained a just view of tjie nature of false
membranes on serous surfaces;2 but as he has given no opinion
concerning the organization of the blood- clot or of the fibrin, it
is unnecessary on the present occasion to consider the important
researches of Mr. Hunter on this point, the more especially as
they are familiarly known in the physiological schools of Britain.

Aristotle3 seems to have ascribed the coagulation of the
blood to the presence of a fibrous matter. It is not certain
whether he considered this matter as existing in the circulation,
or as liquid there, andformed in the blood after it is extravasated.
He noticed that it will not coagulate if the fibres be removed.

Harvey4 supposed that the living blood contains none of the
parts found in it after death. These he described as a cruor
of red and white portions, one dense and fibrous, the other
ichorous and serous, the fibres connecting the whole. It may
be inferred that he was acquainted with the effect of heat upon
serum, — and indeed it is not improbable that Aristotle was.

1 Researches, Physiol. and Anat. vol. ii, p. 49, 8vo, London, 1839.

3 See Note LXXII, page 162.

3 Oper. om. I, p. 457, fol. Aureliae Allobrogum, 1605.

H De Generatione Animalium, pp. 159-60, 4to, Lond. 1651.

C

xxvi INTRODUCTION.

Dr. Willis1 describes the filaments of the crassamentum as
joined together or concreted into a parenchyma. He knew
that serum is coagulable by heat and by some acids, and that
it is the lightest part of the blood.

Malpighi2 washed away the colouring matter of the clot, and
obtained the whitish fibrous part ; he insisted that polypi of
the heart are composed of this fibrous matter, and not of co-
agulated serum as was then generally supposed. He examined
the polypi and the pale substance of the blood-clot with a
microscope, and found them both made up of a fibrous texture
or network, adding that the buffy coat, which he calls pellea
crusta, has probably the same structure. His discovery of the
blood corpuscles is well known.

Lower3 gave a tolerably accurate account of the glutinous
fluid to which the coagulation of the blood and some of its
morbid appearances are owing. He was acquainted with the
effect of heat in coagulating the serum of the blood, lymph,
and the fluid of the pericardium.

The observations of Borelli4 are still more precise. He
described the compound nature of the clot and of the serum ;
the clot as consisting of white fibres or reticulated membranes,
the serum as composed partly of matter coagulable by heat, and
partly of water impregnated with salts. He concluded, from
microscopical observations on the fibres and on the capillary
vessels, that what he describes as the white, glutinous, and
spontaneously coagulable matter of the blood, is liquid in the
living body.

Robert Boyle5 describes the blood as dividing itself into a
fluid or serous and a consistent and fibrous part. He knew
that serum is coagulated by spirit of wine, by sublimate, and
by heat.

Dr. Samuel Collins 6 states that the blood is composed of " a
crystalline liquor and red crassament, which coagulates when

1 Diatribse duae Med. Phil, de Febribus, cap. i, pp. 13, 14, 8vo, Lond. 1659.

2 De Viscerum Structura, accedit Dissertatio de Polypo Cordis, p. 156, 4to,
Bononiae, 1666.

3 Tractatus de Corde, pp. 129-30, and 136, 12mo, Lond. 1669.

4 De Motu Anftnalium, prop, cxxxii, p. 264, Op. Posth. pars alt. 4to,Roma3, 1681.
8 Natural History of Humane Blood, pp. 67, 73, 93, 12mo, London, 1684.

6 System of Anatomy, vol. i, p. 42; vol. ii, pp. 747, 756-7, fol. London, 1685.

INTRODUCTION. xxvii

extravasated, thereby gaining a more solid consistence, produced
by manifold fibres." The blood-clot he regarded as made up
of minute white filaments, or thin membranes inclosing the red
particles. He had a correct idea of the nature of polypi of the
heart ; and his elaborate descriptions of the intimate structure
of the buffy coat, and of the arrangement of the parts com-
posing the clot of buflfy blood, show how accurately he had
examined these subjects for himself, even if he did get his first
knowledge of them from Malpighi.

Bidloo1 figured and described little fibres and the red cor-
puscles in a drop of blood, stating that the fibres, after exposure
for a while, become very tough, tensile, and like network. He
calls the corpuscles globosse vesiculae. William Cowper2 re-
peated Bidloo's plate and description, but thought that the
fibres were accidental, and described the blood as consisting
only of two parts, the serous and globular.

Verduc3 calls the serum serosity, stating that it is the same
as the lymph, or dew of the blood. He says that it is to a
mucilage mixed with the red part that the blood owes its more
or less easy coagulation, and the clot its consistency and union,
while the coagulation of the blood is caused by the collecting
together and the flattening of the little globules.

Gulielmini4 examined coagulated blood microscopically, and
described it as composed of whitish fibres and red globules;
and Michelotti5 attests that the crassamentum consists not of
globules only, but also of most minute and tough fibres.

Sydenham6 describes the buffy coat as solid and fibrous, the
fibres perhaps formed of the sanguineous or red part divested of
its colouring matter. Boerhaave7 regarded the fibrous part of
the blood as chains of globules ; Haller8 mentions fibres gene-
rated from the red portion ; Quesnay9 ascribes the buffy coat

Anatomia Humani Corporis, tab. 23, fig. 16, fol. Amstelaedami, 1685.

Anatomy of Humane Bodies, revised and published by C. B. Albinus, tab. 23,

16, fol. Leyden, 1737.

Traite de 1'Usage des Parties, torn, i, pp. 182, 184, 185, 188, 12mo, Paris, 1696.

De Sanguinis Natura et Constitution, p. 54, 8vo, Venetiis, 1701.

De Separatione Fluidorum in Corpore Animali, p. 286, 4to, Venetiis, 1721.

Opera Omnia, p. 247, Imp. Soc. Syden. 8vo, Lond. 1844.

Academical Lectures, §§221, 223, vol. ii, 8vo, London, 1743.

8 Primae Lineae Physiologiae, § cxlvi, 8vo, Gott. 1780.

9 Traite de la Saignee, pp. 415-16, 8vo, Paris, 1750.

xxviii INTRODUCTION.

to a change in the red corpuscles ; and Bordenave1 had a similar
opinion. These doctrines foreshadow either those of SirE. Home,
or of Mr. Jones and Dr. Simon, mentioned at pages xxxi and xli
of this Introduction, and in the Notes i, xvm, and cxviu.

Ruysch2 obtained the fibrous matter from the blood-clot by
washing, and from fluid blood by agitating it with a twig. He
described the resemblance of the fibres to a true fibrous mem-
brane, and depicted the pseudo-membrane, as he terms it, pro-
cured from his own blood and from that of a pig, on the branch
of an African plant. The ' Ruyschian membrane ' is often men-
tioned by succeeding writers.

At this time, then, the spontaneously coagulable matter of
the blood had been well understood ; while the fibrous structure
of fibrin was thoroughly described, and often with the aid of
the microscope. But the elementary molecules, and the cells
or organic germs in the fibrin were overlooked; for although
Leeuwenhoek3 probably saw either some of these or the pale
floating globules of the blood,4 his description is obscured by
hypothetical errors. The same objection occurs with regard to
the observations made upwards of a century afterwards by Sir
Everard Home and Mr. Bauer,5 though they described and even
accurately measured the pale globules both of the buffy coat of
the blood and of the coagulated lymph in inflamed parts ; and
yet, to suit a preconceived hypothesis, concluded with the error
that these globules are smaller than the red corpuscles.

In Britain, Keill,6 Jurin,7 Thomas Morgan,8 John Cook,9
Arbuthnot,10 William Cowper,11 Martine,12 and Langrish,13

1 Essai sur la Physiologic, torn, i, p. 155, 8vo, 4eme edit. Paris, 1787.

2 Thesaurus Anat. Sept. No. xxxix, tom.ii, p. 19, tab. iii, fig. 6, 4to, Amstelaedami,
1707.

3 Philosophical Transactions, 1675, vol. x, p. 380.

4 For the observations of Senac and Hewson on this point, see Note CXLVI, p. 282.

5 Philosophical Transactions, 1820, pp. 3-5.

6 Essays on several parts of the Animal (Economy, p. 96, 2dedit. 8vo, Lond. 1717.

7 Philosophical Transactions, 1719, vol. xxx, p. 1000.

8 Philosophical Principles of Medicine, pp. 108, 110, 177, 251, 2d edit. 8vo,
London, 1730.

9 Essay on the Whole Animal GEconomy, vol. ii, pp. 18, 19, 8vo, London, 1730.

10 Essay concerning Aliments, pp. 121, 163, 8vo, London, 1731.

11 Anatomy of Humane Bodies, tab. 23, fig. 16, fol. Leyden, 1737.

12 Medical Essays and Observations, vol. ii, pp. 77, 86, 8vo, Edinburgh, 1747.

13 Theory and Practice of Physic, pp. 66-7, 8vo, London, 1735.

INTRODUCTION. xxix

regarded the coagulation of the blood as caused simply by the
running together of the red corpuscles ; and that the crassa-
mentum is formed merely of an aggregation of them was also
the opinion of William Northcote1 and of Dr. Marmaduke
Berdoe.2 Berdoe called the serum serosity. Jurin, Morgan,
and Northcote used the terms serum and lymph synonymously.
Martine denied the existence of the fibres described by Malpighi
in the blood-clot ; Cowper and Northcote expressed a similar
opinion. Huxham3 stated that the buffy coat is caused by the
heat in an ardent fever turning the serum into a jelly; Lister,4
that the serum becomes a stiff jelly by a little standing; and
although Dr. Butt5 described the coagulable lymph, and so
called it, he confounded it with serum and with the white of
egg. Dr. Francis Home6 described the blood as consisting of
crassamentum, serum, and lymph, mentioning, as the properties
of the latter, only those of the serum. To the third and last
volume of the ' Bibliotheca Anatomica/ published in London in
1714, in 4to, some of -the ablest men of the day, as Keill, Drake,
and Yerheyen, contributed essays on the blood, which are re-
markable for errors similar to those above noticed.

On the Continent, Leeuwenhoek7 seems to have considered
the blood as composed only of globules and serum, and the
former as the spontaneously coagulable part. Boerhaave,8 and
his commentator Van Sweiten,9 Haller,10 and Marherr,11 de-
scribed coagulation as a mere conjunction of the red globules,
and the clot as nothing but a cohering mass of them, save some

1 Anatomy of the Human Body, p. 425, Svo, London, 1772.

2 An Essay on the" Nature and Circulation of the Blood, p. 18, Svo, London, 1772.

3 Essay on Fevers, 6th edit. p. 36, Svo, London, 1769.

4 Philosophical Transactions, 1672, vol. vii, p. 5137.

4 De Spon. Sang. Sep. pp. 514-15, 4to, Edin. 1760 ; in Sandifort. Thesaur. torn. ii.

6 An Inquiry into the Nature, Cause, and Cure of the Croup, p. 39, Svo, Edinb.

1765.

7 Philosophical Transactions, 1675, vol. x, p. 380 ; and for 1700, vol. xxii, p. 450 ;
and Select Works, tr. by Sam. Hoole, vol. i, p. 89, 4to, London, 1800.

8 Pralectiones Academics, ed. et Notas additit Alb. Haller. vol. ii, § ccxxvii, Svo,
Gottingae, 1740.

9 Aphor. § 93.

10 Deux Memoires sur le Mouvement du Sang, pp. 21-2, Svo, Lausanne, 1756;
Primae Lineze Physiologic, §§ cxxxvii, cxxxviii, cxliv, cxlvii, Svo, Gottingae, 1780.

11 Preelections in Herm. Boerhaave Institutiones Medicas, torn, ii, pp. 254-55, Svo,
Viennse et Lipsiae, 1772.

xxx INTRODUCTION.

intermixed serum. Distinct from this fluid, these eminent men
had no knowledge of the coagulable lymph ; the same remark
applies to most of the British writers just mentioned ; and, like
some of them, Haller and Marherr believed that the buffy coat
is caused by a change in the serum. Schwenke1 supposed the
nature of that crust to be intermediate to the serum and cruor;
and Gaber,2 even while attesting the identity of the crust with
the matter left after washing the blood-clot and with Ruysch's
membrane, speaks of them as identical with the coagulable
matter of the serum, quoting, in support of this opinion,
Sauvages, de Haen, and Quesnay. Yet Marherr, amid the
vagueness in which he joined, after referring to the opinion of
those who held that there is a fibrous matter in the blood, more
correctly states that the fibres, when obtained by washing from
the clot, are formed from particles which were previously fluid.
Errors similar to those above noticed are contained in the
' Dictionnaire Raisonne d'Anatomie et de Physiologic/ torn, ii,
pp. 381 and 384, 8vo, published at Paris in 1766. While such
were the current opinions, there were some writers, now to be
noticed, who had a clearer knowledge of the blood.

Petit3 declared it to be generally known, that all the parts
of the blood are not susceptible of coagulation ; that it at first
coagulates entirely, but after a while the serum separates from
the clot, as whey does from curdled milk. He always uses the
term serosity for the serum, as Verduc before and many other
writers afterwards did. After stating that this is not the
coagulable part, he says that the next parts are the lymphatic
and the globular ; and then gives a just view of the disposition
of the several parts of the blood in the heart and great vessels
after death, distinguishing the white and lighter clot of lymph
from the red and heavier globular part, and so accurately de-
ducing the effect that the position of the body after death
has on their relative situation.4 In bleeding from the foot, he
described the diffusion of the colouring matter throughout the
water, and the separation of the white part. He declared

1 Haematologia, p. 158, 8vo, Hagae Com. 1743.

2 Melanges de Philosophic et de Mathematique de la Societe Royale de Turin, pour
les annees 1762-1765, pp. 167, 168, 170-72, 4to, 1766.

3 Histoire de 1' Academic Royale des Sciences, ann. 1732, pp. 392-96, 4to, Paris,
1735. 4 See Note xin, pp. 23-4.

INTRODUCTION. xxxi

that the red portion forms no clot without the containing or
enveloping white lymph, and showed that the different de-
grees of consistency of different parts of the clot depend on
the proportion of the white matter, which is most solid when
it coagulates alone; next adding, that if it were possible for
the blood to be fluid until all the lymph rose to the surface,
this would form the only clot, while the globules and serum
would remain fluid. He concluded that the lymph is the only
part of the blood susceptible of self-coagulation.

Quesnay1 observed that the clot is composed of little white
filaments, which he called the fibrous lymph, and of red globules,
the lymph condensing when let out of the blood-vessels, and
retaining the globules in its interstices. He correctly noticed
and drew the right conclusions from the effects of whipping
fresh blood with twigs; on which point Senac's2 knowledge was
afterwards less accurate. Describing the buffy coat, Quesnay3
remarked that the blood is full of many glairy humours, which
in cooling form the crust ; that this is of the nature of lymph ;
and that it collects, from being in a dissolved state, on the
surface of the blood during inflammation, but does not so rise
at the beginning of the disease, before the humour has come to
such a state of dissolution. Hence he concluded, as Hewson
afterwards did from a set of ingenious experiments, I believe4
incorrectly, that the floating of this humour on the blood, far
from showing it to be thickened, proves that its fluidity is in-
creased. Quesnay also stated, in anticipation of a very recent
doctrine,5 and of an older and more generally admitted one,6
that the humour appears to be formed from the molecules, as
he calls the red corpuscles, destroyed and reduced to a glaire by
the action of the arteries ; and that this humour abounds in
acute diseases, at the expense of the molecules, sometimes to
such an extent that the red part of the blood is much diminished.

1 Principes de Chirurgie, pp. 31, 32, 34, 8vo, Paris, 1746.

2 Traite du Coeur, torn, ii, p. 303, 4to, Paris, 1783.

3 Traite de la Saignee, pp. 402, 405, 406, 415, 416, nouv. ed. 8vo, Paris, 1750.

4 See Notes xxi, xxm, and xxix.

5 See the observations of Mr. \Vharton Jones, and Dr. Simon, on the transforma-
tion of the red corpuscles into fibrine, Notes i and cxvui.

6 See the observations of Mr. Hey and others on the increase of the fibrine in the
blood during inflammation, Note i.

xxxii INTRODUCTION.

Senac1 described the whitish substance which congeals of
itself, becomes tenacious, and forms the buffy coat of the blood.2
He terms the pale part indifferently a white oil, lymphatic
matter, white or whitish substance, and coagulated lymph,3 but
never coagulable lymph. He correctly explained the formation
of the buffy coat ;4 and separated the lymph, by washing, from
the blood-clot, as Malpighi had done, and from fluid blood by
whipping it with twigs, after the method of Ruysch, observing
that the latter operation hinders coagulation by removing the
concreting principle or bond of the other parts of the blood,
and that the red part alone cannot unite into a compact sub-
stance; though he also speaks of the coagulation of the red
globules,5 yet not without combating the errors of Leeuwenhoek.6
He observed that the lymph forms clots separate from the red
corpuscles in aneurisms ; that it closes the ends of the great
blood-vessels after amputations,7 and that it differs from the
white of egg and from serum in the property of coagulating
spontaneously.8 After stating that the red particles may be
dissolved and become white,9 he gave reasons for objecting to
the opinion of some writers, perhaps alluding to Sydenham
and Quesnay, that the white part of the blood is formed of the
red, deprived of its colouring matter.10

Examining the lymph microscopically, Senac found no glo-
bules in it, but merely branches or irregularly connected
molecules, the concretion resembling what is observed in a
plate of scarf-skin.11 He correctly states, that the coagulated
lymph forms a kind of membrane, like a true reticular tissue,
but incorrectly ascribes the net-like appearance to other fluids
coagulating with the lymph, and visible with the aid of the
solar microscope.13

1 Traite de la Structure du Coeur, 4to, Paris, 1749; and 2d edit. 4to, Paris, 1774,
which appeared also in 1783, with a new title-page only.

2 Ed. 1749, torn, ii, p. 91 ; and 2d edit. torn, ii, p. 284.

3 Ed. 1749, torn, ii, pp. 91, 449, 453, 75, 96.

4 Ed. 1749, torn, ii, pp. 90, 92, 124, 447 ; and 2d edit. torn, ii, pp. 285, 299, 414.

5 Ed. 1749, torn, ii, pp. 92-3, 447-49, 129.

8 Ed. 1749, torn, ii, pp. 659, 91. 7 Ed. 1749, torn, ii, p. 94.

8 Ed. 1749, torn, ii, p. 95. 9 Ed. 1749, torn, ii, p. 450.

10 Second edit. pp. 413-14.

11 Ed. 1749, torn, ii, p. 660 ; and 2d edit. torn, ii, p. 280.

12 Ed. 1749, torn, ii, pp. 92, 449, 452 ; and 2d edit. torn, ii, pp. 285, 415.

INTRODUCTION. xxxiii

He gave an excellent description, like Malpighr's, of the
blood-clot j1 but added a fanciful explanation of the reticular
or membranous structure of the buffy coat, and of polypi of the
heart, maintaining that the lymphatic juices do not coagulate
into an uniform substance like cheese, because they are com-
pounded with many others ; that the molecules concreting first,
act as wire-drawers to produce the filaments, and the red parts
as balls or grains, between which the congealed juices are
continued as fibres.2

The serum he called serosity, as Verduc and Petit had before
done, and represented it as the vehicle of all the other matters
of the blood.3 He truly observed, in anticipation of Mr.
Hunter's4 experimental proof, that heat cannot be the cause of
the fluidity of the blood of fishes living in iced water during
winter;5 yet, following the experiments cr opinions of Schwenke,
states it to be a fact, that a temperature above 96° keeps the
blood liquid ;6 that its liquidity is preserved by agitation in a
bottle ; that a large quantity of nitre or of sea-salt coagulates
the blood when kept still, though it remains fluid if agitated ;7
next, that these salts prevent coagulation;8 and finally, that
nitre, injected into the veins, coagulates the blood.9

The second edition of Senac's work contains many of the
crudities of the first, and several improvements in matters which
had been made clear by the experiments of Hewson. Thus,
although Senac retained his vague notion of several sponta-
neously coagulable matters in the blood, to wit, lymph, fat,
mucous matter, and gelatinous juices,10 he introduced a state-
ment, not in the first edition, that it is the lymph only which
coagulates;11 and to prove, according to divers writers, that the
exclusion of air makes the blood less susceptible of coagulation,
he details an experiment of his own,12 inconsistent with the
accurate knowledge he had formerly shown of the effect of re-

1 Ed. 1749, torn, ii, p. 449 ; and 2d edit. torn, ii, p. 415.

2 Ed*. 1749, torn, ii, p. 450 ; and 2d edit. torn, ii, pp. 415, 416.

3 Ed. 1749, torn, ii, p. 104 ; and 2d edit. torn, ii, p. 292.

* Works, edited by Mr. Palmer, vol. iii, p. 26, 8vo, London, 1837.

5 Ed. 1749, torn, ii, p. 133 ; and 2d edit. torn, ii, p. 302.

6 Ed. 1749, torn, ii, p. 133. 7 Ed. 1749, torn, ii, p. 134.
8 Ed. 1749, torn, ii, p. 136. 9 Ed. 1749, torn, ii, p. 459.

10 Second edit. torn, ii, pp. 285, 414, 416.

11 Second edit. torn, ii, p. 302. 12 Second edit. torn, ii, p. 303.

xxxiv INTRODUCTION.

moving the coagulable lymph from the blood by whipping it
with twigs. In the second edition, too, he dwells on the evi-
dence of the flat shape of the corpuscles,1 and omits the vague
observations which he had given in the first edition on the effects
of neutral salts, and on the fluidity of the blood being preserved
by a heat of 96°.

The doctrine of Leeuwenhoek was taught by the first Dr.
Monro, at Edinburgh, up to the year 1758; and the first
lectures of his son2 and successor were employed in refuting
this system, and in proving the distinction between the different
parts of the blood.

Dr. J. M. Butt3 followed Malpighi in the description of the
blood-clot, adding that Senac aptly named the fibrous part
coagulable lymph, which also forms the part commonly called
the inflammatory crust. Yet Dr. Butt says the serum is com-
posed of coagulable lymph, watery fluid, and saline matter.
He stated that if serum be exposed to a heat of 150°, it con-
cretes into an uniform mass, from which exudes, after it is cut
into thin slices, a watery saline liquor, called serosity by Senac.
I have not met with an expression exactly equivalent to coagu-
lable lymph in Senac' s work, though, as I have already noticed,
he mentions coagulated lymph, and lymph which coagulates of
itself; and he used the word serosity merely for the serum.
Sir John Pringle4 mentioned, in a note to a paper read before
the Royal Society, February 13, 1752, that the inflammatory
crust is the same part of the blood as that called by M. de Senac
the white matter which coagulates of itself.

Gaubius5 distinguished the three proximate constituents of
the blood. He described the fibre as forming the basis of the
clot, and as exceedingly different from the red part and from the
serum, especially in the power of coagulating spontaneously.
The inflammatory diathesis he attributed to a mucus generated
in the serum and coagulating in the manner of the fibre ; and

1 Traite du Coeur, 2d edit. torn, ii, p. 276-77.

2 Essays and Heads of Lectures, &c., and Memoir of Dr. Alexander Monro secuudus,
by his Son and Successor, p. xiv, 8vo, Edinburgh, 1840.

3 De Spontanea Sanguinis Separatione, pp. 504, 514, 521, 510, 4to, Edinb. 1760;
in Sandifort. Thesaur. Dissert. 4to, Roterodami, 1769.

4 On the Diseases of the Army, 5th edit. App. p. Ixxiv, 4to, London, 1765.

5 Institutions Pathologise Medicinalis, $$ 339, 344, 340, 361, 367, 280, 345-47,
8vo, Leid. Bat. 1758.

INTRODUCTION. xxxv

the pleuritic coat to an undue tenacity of the fibre, connected
with an increase of its quantity in proportion to the serum,
and with a condensation of the serum into the fibre. He
regarded the constitution of blood and milk as so nearly alike,
that the one might be called red milk, and the other white
blood ; comparing the serum of blood to whey, the red part to
cream, the fibre to curd, and the red corpuscles to oily globules
like those of milk.

Dr. Richard Davies1 observed that the inflammatory pellicle
is formed by the coagulation of a fluid, a gluten natural to the
blood, rising to the surface, and exactly similar to the con-
creted substance obtained from the blood by stirring it with a
tube. He washed the crassamen, as he calls it, with water, and
described the remaining gluten as resembling a congeries of
pellucid membranes and fibres (pp. 5-9), expressly declaring, in
opposition to Jurin, that the red globules do not possess any
strong cohesion to form a mass or compact body, without the
interposition of the gluten, (pp. 11, 12.) This, Davies adds, ac-
quiring tenacity by cold and rest, causes coagulation ; and then
by its concreting force, presses out the serum, so that " the
denser the texture of the gluten is, the more serum it presses
out ;" and when no serum separates from the blood, it usually
remains a tender coagulum, not from a defect of serum, for
then the coagulum would be dense, but from the weakened
contraction of the glutinous parts, (pp. 15-19.)

The inflammatory pellicle he ascribed, as Quesnay before,
and Hewson afterwards did, to a preternatural attenuation or
fluidity of the gluten, permitting the red globules to subside
while it rises with the serum to the surface. Here the gluten
exerting its full cohesive force, becomes a firm membrane, or
more compact body than that part of the clot which has its
cohesion broken by the intervention of the red globules. Thus
the gluten squeezes out the serum and compels the crassamen
into a more regular form. (pp. 23-24.) He fixes the specific
gravity (p. 13) of the serum at 1-026, of the pellicle of inflamed
blood, as he terms the bufiy coat, at 1-056, and of the crassamen
at 1-084, adopting Jurin's estimate, with some reservation, of
the red globules at 1-126.

1 Essays to promote the Experimental Analysis of the Human Blood, by Richard
Davies, M.D., late Fellow of Queen's College in Cambridge, 8vo, Bath, 1/60.

xxxvi INTRODUCTION.

Dr. Davies seems to claim for himself the discovery of the
gluten, ignorant perhaps, like some of his successors, of the facts
ascertained by the earlier observers. Discussing the sources
of error in Jurin's estimate of the weight of the red corpuscles,
Dr. Davies says, "These objections could not occur to Dr. Jurin,
because the gluten had not been discovered as a constituent
part of the blood. So many errors therefore are detected and
removed in consequence of this one discovery" (pp. 15-16) ; and
mentioning, towards the end of his Essay, the want of success
before made in these studies, he adds, "One difficulty at least is
hereby removed, in the manifest exhibition of the three distinct
portions of the blood." (p. 51.)

Dr. William Hunter1 at the end of the year 1759 was well
acquainted with these portions, especially distinguishing the
spontaneously coagulable principle, which, like Borelli and
Davies, he termed gluten, but asserted that it was " formerly
falsely called fibrous." The word gluten was often used for the
same part still later, as by William Hunter's pupil, Dr. Hugh
Smith,2 who had a similar knowledge of the blood, by the re-
viewer3 of Mr. Key's work, and by Dr. Henry.4 There is no
evidence that Dr. Hunter's knowledge of the properties of the
gluten was of an earlier period than that above noted, and
it is the exact date afterwards mentioned incidentally by him-
self.5 Two years before, while carefully describing the con-
tents of an aneurism,6 he used no term which shows that he
was then familiar with the coagulable lymph; but says that
the clot, "towards its outside, was as hard and as tough as
a cake of glue that had been soaked in cold water, and of a
cineritious complexion; towards its inside, it was more tender
and of a redder colour. The laminae of which it was com-
posed were thin as paper, regular, and did not readily separate
from each other, especially in the tougher external part of

1 Anatomical, Physiological," and Chirurgical Lectures, p. 4, 4to, MS. 1759, in the
Library of the Royal Medical and Chirurgical Society, London, Press mark B, i, 17.

2 Essay son the Nature and Circulation of the Blood, pp. 12, 18, 12mo, London, 1761.

3 In the Medical and Philosophical Commentaries, by a Society in Edinburgh,
vol. vi, p. 380, 8vo, London, 1779.

4 Epitome of Chemistry, p. 125, 12mo, London, 1801.

5 Medical Commentaries, Part I, pp. 39, 41, 4to, London, 1762.

6 Medical Observations and Inquiries, by a Society of Physicians in London, vol.
i, pp. 347, 348, 8vo, London, 1757.

INTRODUCTION.

XXXVll

the coagulum." He asks, in endeavouring to account for the
erosion of bone in contact with an aneurism, whether the blood
has the property of dissolving bony matter, and mentions what
he regarded as evidence in the affirmative.1 Again, in his im-
portant Remarks on the Cellular Membrane,2 read Oct. 31,
1757, and published in 1762, he says, "in adhesions of parts,
that follow in consequence of inflammation, we observe that the
surfaces are first glued together by a mucusf and every wound
that is healing is naturally covered by a bed of soft mucus in
which the vessels shoot." He used the term lymph for " the
interstitial fluid of living bodies." Describing the effects of
inflammation of serous membranes, and the pus which is formed
without any breach in the solids, he writes, "it is only a sort
of inspissated serum, or an inflammatory exudation . . . the
containing surface is more or less covered with a glutinous
concretion or slough of the same colour as the fluid . . . but
still the surface covered by these sloughs is without ulceration
or loss of substance."

Thomas Houlston4 was acquainted with the three parts of
the blood, and he used the term coagulable lymph in the
same sense as it has long since been employed. He refers to
the experiments of his friend Hewson as to the heat which
coagulates this lymph, and concludes that the blood is not so
viscid in inflammation as in the natural state. Mr. Houlston's
dissertation is dedicated to

Dr. George Fordyce, who remarked, among other symptoms
of the inflammatory diathesis, that the blood when drawn is
more fluid, so that the red globules fall to the bottom and the
coagulable lymph forms the buff or crust on the top.5 He
afterwards 6 described the coagulable lymph more fully, to wit,
fluid in the circulation at any degree of heat between 30° and
120° of Fahrenheit's thermometer; coagulating when taken

1 Medical Observations and Inquiries, by a Society of Physicians, vol. i, pp. 344,
345, 8vo, London, 1757.

2 Medical Observations and Inquiries, vol. ii, pp. 28, 48, 61, 62.

3 The italics are Dr. Hunter's or his printer's. The word mucus was used in its
modern restricted sense by Dr. Arbuthnot, in his Essay on Aliments, p. 183, pub-
lished in 1731, several years before Dr. Hunter wrote.

4 Diss. Med. Inaug. de Inflammatione, pp. 11, 12, 14, 4to, Lugd. Bat. 1767.

5 Elements of the Practice of Physic, p. 28, Part II, 8vo, Swan, London, 1768.

6 Ibid. pp. 4, 6, Part I, 8vo, Johnson and Payne, London, 1770.

xxxviii INTRODUCTION.

out of its vessels, whether in motion or at rest, exposed to the
air or not, in the heat of the human body or in any other de-
gree of heat ; continuing fluid for more than three hours when
retained in the blood-vessels, in motion or at rest, in any heat
between 30° and 120° ; and its coagulation prevented by satu-
rating the whole blood with common salt and perhaps by some
of the other neutral salts. His account of the formation of the
buify coat is similar to Hewson' s, even stating that it will occur
on blood which has some time been stagnated in its vessels
before it is let out. Dr. Fordyce had a perfectly clear know-
ledge of the distinction between the coagulable lymph, the red
corpuscles, and the serum. Fordyce and Houlston are probably
alluded to in Hewson' s note to the end of the second chapter
of the first part of his ' Experimental Inquiries/ p. 41, where he
says that his facts had been mentioned in his lectures ever since
1767 or before. A creditable contemporary writer, Dr. David
Macbride1 first quotes Fordyce concerning the buffy coat, but
afterwards2 corrected himself by adding that " the late Mr.
Hewson was the first that accounted for the formation of the
buff in the manner above described :" and Dr. Foart Simmons,3
after having quoted the same observation on the authority of
Dr. Fordyce, concluded by giving it entirely to Mr. Hewson.
In the library of the medical department of the army, at
Chatham, there is a quarto copy of manuscript notes from Dr.
Fordyce's Lectures on the Practice of Physic, marked on the
cover, " E. Scott, 1 764." The term coagulable lymph is cor-
rectly used in that manuscript for a part of the matter which
causes the swelling in inflammation, and incorrectly for the
lateritious sediment of the urine in the same disease.

Hewson removed the coagulable lymph in its fluid state from
the blood, and proved that the coagulation of the lymph is
quite independent of the other parts. His experiments on
the effects of various temperatures on its coagulation are very
interesting and original; by freezing the blood he suspended
its coagulating power, and restored it by thawing. To enable

1 A Methodical Introduction to the Theory and Practice of Physic, pp. 229-30,
4to, London, 1772.

2 Op. cit. 2d edit. vol. i, p. 294, 8vo, Dublin, 1777.

3 Elements of Anatomy, from the French of M. Person, note to p. 327, 8vo, Lond.
1775 ; and 2d edit. 1781, p. 345.

INTRODUCTION.

XXXIX

him the better to investigate the properties of the lymph, apart
from the red corpuscles, he kept it fluid by neutral salts, and
proved that it would yet coagulate after the addition of water.
He showed from precise observations how much longer coagu-
lation is in taking place when the blood is stagnated, either
artificially or from natural causes, in its own vessels, than when
it is removed from them. His experiments on the comparative
rate in the sinking of the red corpuscles in what has since been
called the liquor sanguinis and in the serum were highly novel,
ingenious, and correct.1 He described accurately the part per-
formed by the coagulable lymph in diseases ; how the fluid of
dropsies differs from that lymph and from the serum; and
carefully examined the properties of the fluid of the lymphatic
vessels and of the serous sacs. The theoretical conclusions to
which he was led by those inquiries, on the secretion of lymph
into serous sacs and on the pathology of the lymphatic system,
contain the sum of nearly all that is at present known on those
subjects.

In considering the labours of Hewson in connexion with
the facts observed and the errors held by his predecessors and
contemporaries, it must be recollected that the speculations
connected with Leeuwenhoek's microscopical researches for
many years supplanted accurate experimental inquiries into the
properties of the blood ; so that the fibrin was either forgotten
or confounded with the serum, and a fanciful importance was
given to the red corpuscles. When the errors consequent on
this state of things began to wane, the blood sunk into neglect.
Accordingly, the just observations of Malpighi, Lower, and
Borelli, were lost for the greater part of a century, while the
coagulation of the blood was ascribed to a mere cohesion or
running together of the red corpuscles, and the formation of
fibrinous clots to a change in the serum. These opinions were
held in Britain by the best writers to the year 1760, and on
the Continent by the most distinguished physiologists, as Haller
and Marherr, up to or even beyond 1771, the date of the first
edition of Hewson's ' Inquiry into the Properties of the Blood/
But there were exceptions. The knowledge of Petit, Quesnay,
Senac, and Gaubius, was unquestionably in advance of that
current in their day; yet they added but little to the facts of
1 See Note xxm, p. 40.

xl INTRODUCTION.

the older observers, so vaguely discussed by Haller,1 so ably
used in the masterly memoir of Petit ; and some of the opinions
set forth by Quesnay and Senac, partook of that general cru-
dity which proved how necessary it was that the properties of
the blood should be studied anew by the experimental method.
The merit of clearly apprehending the importance of such an
inquiry and of supplying an outline of it, justly belongs, I believe,
to Richard Davies. His ' Essay/ considered as a demonstration of
the distinctive characters of the three proximate principles of the
blood, is admirably decisive. Yet it seems to have fallen dead-
born from the press, and his labours have been hitherto left to
oblivion. Why he has suffered this injustice it might be vain
or painful to inquire. There is no reason to believe that he
derived his knowledge from Dr. William Hunter ; on the con-
trary, this distinguished anatomist may rather have gained his
knowledge of the blood from Davies. There is a copy of his
' Essay' in Dr. Hunter's library at Glasgow. It appears pro-
bable, from what has already been shown, that Dr. Hunter did
not entertain his opinions before the end of the year 1759; his
denial of the fibrous structure of fibrin would lead us to sup-
pose that he had not then studied it very carefully, and we are
not sure that he ever did experimentally. Now it is certain that
Dr. Davies had made experiments on the blood at least as early
as 1 748, because he gave the results of his own observations on
the comparative weights of the serum, buffy coat, and crassa-
men, in his ( Tables of Specific Gravities,' communicated to the
Royal Society by its then president, Martin Folkes, and pub-
lished in the ' Philosophical Transactions' of that year. Davies
there mentions the buff as f( sanguinis humani cuticula alba,"
whence it might be imagined that he had not then examined
its nature, But in his ' Epistle to the Reverend Doctor Hales,
being Introductory to the Essays on the Blood,' Davies says that
he had drawn the principal lines of the first essay full twenty-
five years before, and that he hopes the publication of it may
engage younger eyes and younger minds in such studies, adding,
in a postcript, dated March 1, 1759, that the first essay was
then in the press. I know not that he ever published another.
Twenty-five years before the date of the epistle to Hales would
be in 1734, when Dr. Hunter was but sixteen years of age.
1 Elementa Physiologic, torn, ii, pp. 42, 125, 4to, Lausannae, 1760.

INTRODUCTION. xli

May not, therefore, Dr. Davies be considered as having re-
vived and established that correct knowledge of the distinct
characters of the three parts of the blood which was taught by
Hewson, Fordyce, and the Hunters ? Certain it is that there
was a general ignorance on the subject in England when
Davies wrote his Essay. Nor was the gloom in which the
truth had been hid for nearly a century dispelled by the fitful
lights of the able French physiologists before mentioned. Hence
the honour of displacing the current errors by accurate doctrines
fairly settled on experimental proofs would appear to belong,
as Dr. Davy observes, chiefly to our countrymen.

Among these Mr. Hewson was unrivalled, and has perhaps
never been surpassed, for the skill with which he prosecuted
this right method of inquiry. His work on the ' Properties of
the Blood' is a model of experiments nicely devised, well
executed, and clearly told ; often original, ever instructive ; a
happy combination of precision and simplicity, and an admi-
rable reflection of the character of his mind.

Nothing can be plainer than the proofs given by Hewson
that the coagulation of the blood is alone dependent on the
fibrin ; nor is there a jot of evidence that either he or Davies
ever supposed that the red corpuscles have anything whatever
to do with that coagulation. On the contrary, Hewson was wont
to obtain them in the entire state from the clot ; he had well
established that their form in the blood is preserved by the
saline matter of the serum, and by watery solutions of neutral
salts out of the body ; while the mixture of these salts with the
blood was one of the means by which he separated the fibrin,
as Miiller afterwards did, from the red corpuscles.

There was, indeed, an old and discarded hypothesis, already
noticed, entertained by Sydenham, Quesnay, and Bordenave, that
the fibrin of the blood is formed of the colourless matter of the
red corpuscles. Sir Everard Home1 and Mr. Bauer revived this
opinion in the more specious form, that the fibres of fibrin and
of muscle are composed of rows of the nuclei of the corpuscles di-
vested of their coloured envelopes. A similar doctrine was soon
afterwards brought forward in France by Prevost and Dumas, 2

1 Croonian Lectures, Philosophical Transactions, 1818 and 1820.

2 Examen du Sang, Annales de Chimie et de Physique, torn, xviii et xxiii, 8vo, Paris,
1821 and 1823.

d

xlii INTRODUCTION.

supported and extended by Milne Edwards/ and adopted by
Dutrochet,2 Beclard,3 and others.

But it never took root in Britain, where, although Davies
was forgotten, the accurate conclusions of Hewson remained
current in the schools and among the best independent ob-
servers. Thus Dr. Davy4 always considered the three parts of
the blood distinctly ; he defined coagulation to be a change
from the liquid state of fibrin to the solid, and showed that
fibrin is viscid before it becomes firm, so accounting for mor-
bid adhesions. This change in the fibrin from a liquid to a
solid, was the chief fact from which the supposed production
of heat in coagulation was inferred, originally, I think, by
Fourcroy. Dr. Gordon,5 Mr. Wilson,6 Dr. Babington,7 and
others, plainly distinguished the three parts of the blood; and we
have the excellent testimony of Dr. Sharpey8 that Dr. Gordon
was in the habit of giving, in his lectures, an account of serum
and fibrin being the products of the coagulation of the trans-
parent blood-fluid, as the common opinion of physiologists. In
like manner Mr. Abernethy, in his lectures, when I was his
pupil, used to distinguish the different parts of the blood, just
as Mr. Hunter9 had written after Davies, Dr. Hunter, and
Hewson. Moreover, the exact observations of Dr. Hodgkin
and Mr. Lister10 were quite against the views of Sir Everard
Home and Dr. Milne Edwards ; and in 1829 we find an eminent
Teacher11 declaring that the new theory had been proved in
this country to be erroneous.

In Germany the difference between the corpuscles of the

1 Repertoire General d'Anatomie et de Physiologic, torn, iii, 4to, Paris, 1827.

2 Recherches sur la Formation de la Fibre Musculaire, Annales des Sciences Natu-
relles, torn, xxiii, 8vo, Paris, 1831.

3 Elemens d'Anatomie Generate, pp. 81-3, 8vo, Paris, 1827.

4 Tent. Exp. quaedam de Sang. Comp. p. 15, 8vo, Edinb. 1814 ; Journal of Science
and the Arts, ed. at the Royal Institution, vol. ii, p. 248, 8vo, Lond. 1817 ; Philoso-
phical Transactions, 1822, pp. 273-4.

6 Outlines of Lectures on Human Physiology, p. 60, 8vo, Edinburgh, 1817.

6 Lectures on the Blood, pp. 28 et seq., 8vo, London, 1819.

7 Medico-Chirurgical Transactions, vol. xvi, pp. 293 et seq., 8vo, London, 1830.

8 Mailer's Physiology, tr. by Dr. Baly, vol. i, p. 110, 8vo, London, 1838, 1st edit,

9 Works, ed. by Mr. Palmer, vol. iii, pp. 17, 20, 24, 8vo, London, 1837.

10 Philosophical Magazine, vol. ii, pp. 131 et seq., July to December, 1827.

11 Mr. Grainger, Elements of General Anatomy, p. 46, 8vo, London, 1829.

INTRODUCTION. xliii

blood and the globules of the tissues was insisted on by
Tiedemann;1 and Burdach2 resisted the hypothesis that the
fibrils of fibrin are composed of globules ; while in France De
Blainville3 declared that such a structure was seen only by the
dupes of an optical delusion.

But this delusion must have been widely spread on the Con-
tinent. Besides the writers already cited, Professors Miiller4
and Wagner/ and Dr. Milne Edwards,6 state that it was gene-
rally believed that coagulation is produced by a rnnning toge-
ther of the red corpuscles, before Berzelius announced that the
fibrin is liquid in the flowing blood, and becomes solid in the
clot. This last opinion, as I have before shown, was both a
very old and a very new one when that eminent chemist ad-
vanced it. That it will ever be commonly known as a fact
established long ago is almost too much to hope ; for M. Denis7
has even lately declared that he was the first to admit the
liquidity of the fibrin in the circulating blood !

Professor Miiller witnessed coagulation in the liquor san-
guinis after he had filtered it from the red corpuscles of the
frog ;8 and he preserved for a while the fluidity of the blood of
man and other vertebrate animals with carbonate of potash, so
that the corpuscles sunk, and the liquid fibrin became solid above
them.9 Of these experiments, the first was new and ingenious
in form ; the second was of an old sort and more complicated
than some of Hewson's ; but neither was required to demon-
strate the accuracy of his views, because he had already done
that by the most simple, direct, and conclusive experiments.

And even if the researches of Hewson and of his prede-
cessors and successors were to be set at naught, British phy-
siologists had, before Professor Muller's experiments were
known here, generally adopted Dr. Babington's term, liquor

1 Physiology, tr. by Dr. Gully and Dr. Lane, vol. i, p. 397, 8vo, London, 1834.

2 Traite de Physiologic, tr. par Jourdan, torn, vi, pp. 34, 59, 8vo, Paris, 1837.

3 Cours de Physiologic Generate et Comparee, torn, i, p. 234, 8vo, Paris, 1829.

4 Physiology, tr. by Dr. Baly, vol. i, pp. 109-10, 1st edit.

5 Physiology, tr. by Dr. Willis, p. 264, note, 8vo, London, 1844.

6 Cyclopaedia of Anatomy, vol. i, p. 413, 8vo, London, 1836.

7 Essai sur 1' Application de la Chimie a 1'etude physiologique du Sang de 1'Homme,
pp. 67, 356, 8vo, Paris, 1838.

s Annales des Sciences Naturelles, torn, xxvii, pp. 222-4, 8vo, Paris, 1832.
' Physiology, tr. by Dr. Baly, vol. i, p. 112, 1st edit.

xliv INTRODUCTION.

sanguinis, for the fluid mixture of fibrin and serum in the
circulating blood.

In the London schools Mr. Hunter has long been regarded
as the great authority on the coagulation of the blood ; and
to crown the confusion, the discovery of the leading property
of what he always considered as the most important part of the
blood, the coagulable lymph, has been awarded to him. Thus
the Hunterian Professor, Mr. Owen,1 asserts that " Hunter sub-
jects the blood both to mechanical and chemical analysis, and
endeavours to determine the characteristic properties of its dif-
ferent constituents. It was not known in his time upon which
of these constituents the act of coagulation depended. Hunter
took advantage of a case in which the red globules subsided,
as in some cases they do, more rapidly than usual, and skim-
ming off the superincumbent colourless fluid, found that the
fibrin, as it is now termed, immediately coagulated and formed
a colourless clot. A subsequent erroneous theory, which
attributed the act of coagulation to the red globules, has
recently been set aside by the application of an ingenious pro-
cess for artificially separating the fibrin from the blood discs
before coagulation takes place, and the opinions of Hunter
on this point have been fully established by the experiments
of Miiller."

Now Mr. Hunter was well acquainted with Hewson's work
on the f Properties of the Blood/ in which this simple experi-
ment of skimming off the liquor sanguinis was detailed, with
all the legitimate deductions from it, many years before 1794,
when Mr. Hunter's ' Treatise on the Blood ' was published ;
and how much longer the fact which the experiment proves
had been known, may be gathered from the foregoing narrative.
Besides, an eminent English surgeon2 had commented on and
frequently repeated JMr. Hewson's experiment in 1779.

I know not that Mr. Hunter ever claimed for himself the
discovery of any one of the three constituents of the blood.
Theperosity,3 of which he thought himself the discoverer, and
the paleness which he is said, by Mr. Owen, to have discovered
in the blood of the early embryo of vertebrate animals,4 had

1 Hunter's Works, vol. iv, p. xii, 8vo, London, 1837.

2 Mr. Hey, Observations on the Blood, pp. 10-12, 8vo, London, 1779.

3 See Note LIV, p. 79. 4 See Note en, p. 222.

INTRODUCTION. xlv

both been described long before Mr. Hunter published on
those subjects. After stating that the coagulation of the
blood out of the circulation would seem to be unconnected with
life,1 Mr. Hunter2 says that he conceives the simple act of
coagulation, apart from its causes, to be an operation of life,
proceeding upon the same principle as union by the first in-
tention, adding that the coagulation of the blood appears to be
that process which may be compared with the action of life in
the solids. He gave an excellent description of the toughness
and elasticity of a clot of fibrin, and of its fibrous and laminated
structure; and when he inferred how a membrane may be
formed of that part of the blood, he was entering on a most
interesting and philosophical inquiry, which he pursued with
a perseverance and success very characteristic of his ardent
genius. In blood removed from the body, he proved, experi-
mentally, that no heat is produced during the act of coagulation ;
and he described, in anticipation of some of the most recent
observations, the aggregation of the red corpuscles and the con-
sequent mottled appearance of the blood during the formation
of the buffy coat.3

About the time when Mr. Hunter's ( Treatise on the Blood'
appeared, the term fibrin was introduced by the French che-
mists, and used in its present sense by Fourcroy, in his ' Sys-
teme des Connaissances Chimiques/ published at Paris in 1 801 .

The old observations on the fibrous structure of fibrin have
often since been revived, and sometimes insisted on as dis-
tinguishing it from coagulated albumen, particularly by Dr.
Henry,4 Mr. Dowler,5 and Dr. Alison;6 while the fibrils of
fibrin have been examined again with the aid of the micro-
scope by Lauth,7 Magendie,8 and many others. Heidmann9

1 See Note xn, p. 21.

2 Works, ed. by Mr. Palmer, vol. iii, pp. 20, 34, 113, 23-24,35-36 ; and vol. i, p. 235.

3 See Notes xxi, xxm, and xxix.

4 Epitome of Chemistry, p. 125, 12mo, London, 1801.

5 Medico-Chirurgical Transactions, vol. xii, p. 87, 8vo, London, 1822.

6 Outlines of Physiology and Pathology, p. 43, 8vo, Edinburgh, 1833.

7 L'Institut, Journal General desSocietes et Travaux Scientifiques, No. 70, p. 301,
4to, Paris, Sept. 13, 1834.

8 Lectures on the Blood, Lancet, 1838-39, vol. i, pp. 460, 255.

9 Noticed in Tiedemann's Systematic Treatise on Comparative Physiology, tr. by
Drs. Gully and Lane, vol. i, p. 150, 8vo, London, 1834.

xlvi INTRODUCTION.

described motions in the fibrils during the coagulation of fresh
blood.

Magnus Falconar1 published the third part of the Experi-
mental Inquiries in 1777. He has explained his share of the
work in the preface. He appears to have written the last
four chapters with great care and fidelity ; but it is probable
that Hewson would have altered some of the statements, had
he ever seen them.

Hewson's observations are more exact and complete than
any that had before been made on the red corpuscles. He
finally exploded the error of Leeuwenhoek that those of the
mammalia are spherical, by proving their flat figure, and show-
ing that they may accordingly be seen laid one against another
like coins. He proved that water renders them spherical, that
their flat shape is preserved by the saline matter of the serum,
or by a weak solution of a neutral salt, and that they are con-
tracted or shrivelled by a strong solution. His demonstration
of the nucleus and vesicle in the corpuscle of lower vertebrate
animals is excellent. He observed the important facts, now
generally admitted, that there is a difference of character
among the corpuscles of the same blood; that they are larger
in the embryo than in the adult; and that they split into
an irregular number of pieces, under certain circumstances,
from the circumference to the very centre, while each of these
portions retains its red colour, contrary to a leading tenet of
Leeuwenhoek's hypothesis.

He was the first to examine accurately the fluid of the
lymphatic system, of the thymus and of the vessels which
run from it into the veins at the lower part of the neck. He
described the corpuscles common to all these fluids, and saw
the pale globules in the blood. The lymphatic vessels just
mentioned of the thymus, he concluded, like Sir Astley Cooper

1 Mr. Falconar was born at Cheltenham, in Gloucestershire, in November, 1754.
He married Hewson's sister, and died of pulmonary consumption at Bristol, March
24, 1778, at the age of 24. He was a man of great application and dexterity, and a
good speaker. The sale of his collection of anatomical preparations, which included
those made by Hewson, produced upwards of £900. (Dr. Simmons's Life of Dr.
Hunter, p. 58.) Mrs. Hewson (Mr. Pettigrew's Life of Dr. Lettsom, vol. i, p. 146,
of the Correspondence) says that her husband desired on his death-bed that he should
be succeeded in the Anatomical School by Mr. Falconar.

INTRODUCTION. xlvii

afterwards, to be its excretory ducts;1 and he formed the
same opinion of the lymphatics of the spleen. He observed
the ruddy colour produced by the presence of blood-corpuscles
in the lymph of this organ; and although he concluded that
the office of the spleen is to form their red envelopes, he be-
lieved that it is not the only part destined to this function,
since he confirmed the truth of the old observation, that the
spleen may be removed without a permanent ill effect, and
that the blood-corpuscles may be perfectly formed in the
lymphatic system generally. Similar views as to the office
of the spleen have been lately arrived at by inquirers,2 probably
still ignorant of Hewson' s labours. His researches concerning
the use of the glands without regular excretory ducts show
the marks of an active and ingenious mind, and I believe first
indicated a rational method of research into this important
and recondite branch of physiology. His observations on the
lymphatic glands are in the same spirit ; and his doctrine of
central particles,3 so long looked upon as visionary, was a step
far in advance of the age in which he lived.

The relation between the lymph-globules and the red cor-
puscles of the blood, originally announced by Hewson, has
been advanced anew from independent observations by some
of the best physiologists on the Continent. Professor Wagner4
agrees with Nasse in concluding that the lymph -globules are
free nuclei of the blood-corpuscles. Mulder0 assumes that
these corpuscles originate from those of lymph ; and Schultz,
Henle, and Simon6 entertain the same opinion.

Yet, of all Hewson's able contemporaries and immediate
successors, Magnus Falconar alone perceived the importance of
this subject, and entered on the new field of inquiry with an
honest zeal, unfortunately arrested by a death still more pre-
mature than that of Hewson. The conduct of Falconar in
the use which he made of the materials intrusted to him by
his deceased friend was every way just and generous, nobly

1 See Note cxxvii, p. 261.

2 See Note cxxxni, p. 273. 3 See Note cxxn, p. 254.

4 Elements of Physiology, tr. by Dr. Willis, p. 253, 8vo, London, 1844.

5 Chemistry of Vegetable and Animal Physiology, tr. by Dr. P. F. H. Fromberg,
Part II, p. 344.

6 Animal Chemistry, translated for the Sydenham Society by Dr. Day, vol. i, pp.
120-21, 8vo, London, 1845.

xlviii INTRODUCTION.

repaying Hewson's confidence, and affording an honorable
example of integrity, which, in matters of science, has sometimes
been disregarded with less temptation of gain and impunity,
though with a sacrifice of that higher feeling which must have
warmed the breast of Mr. Falconar.

Had these two ingenious men lived to continue the inquiry
which they had so successfully begun, it is not improbable that
the important results obtained by Schwann would long since
have been anticipated in this country; for, as I have elsewhere1
remarked, the researches of the German physiologist show that
what Hewson propounded of the blood-corpuscles particularly
is applicable to the tissues generally, and that the cell-nucleus
of the present day is but another term for the central particle
of Hewson.

Hewson's style has generally the merit of precision and
clearness, so essential to scientific narrative. From his matter
he never wanders into the airy regions of mere speculation ;
although he had sometimes the fault, not uncommon in young
and ardent minds, of pushing his conclusions beyond their just
limits. But, even then, his reasoning is seldom wrong accord-
ing to the facts upon which it is founded; and the means
of observation and the state of knowledge at the time were
scarcely sufficient to extend his premises.

Upon the whole, Hewson was a great benefactor to science;
and if his works are not weighty and comprehensive enough to
place him in the first class of physiologists, he is certainly
entitled to the most exalted rank in the second, and to a high
station among the eminent British Worthies.

1 Appendix to the English edition of Gerber's Anatomy, p. 100, 8vo, London, 1842 ;
and Note to Dr. Willis's translation of Wagner's Physiology, p. 250.

LIST OF HEWSON'S WRITINGS.

1. The Operation of Paracentesis Thoracis, proposed for Air in the Chest; with

some Remarks on the Emphysema, and on Wounds of the Lungs in general.
By Mr. William Hewson, Reader of Anatomy. Communicated by Dr. Hunter ;
read June 15, 1767. — Medical Observations and Inquiries, by a Society of
Physicians in London, art. xxxv, vol. iii, pp. 372-96, 8vo, London, 1767.

2. An Account of the Lymphatic System in Birds. By Mr. William Hewson, Reader

in Anatomy : in a Letter to William Hunter, M.D., F.R.S., and by him com-
municated to the Society. Received October 3, 1768 ; read December 8,
1768.— Philosophical Transactions for the year 1768, vol. Iviii, pp. 217-26.

3. An Account of the Lymphatic System in Amphibious Animals. By Mr. William

Hewson, Lecturer in Anatomy : in a Letter to William Hunter, M.D., F.R.S.,
and by him communicated to the Society. Received June 19, 1769; read
November 9, 1769. — Philosophical Transactions for the year 1769, vol. lix,
pp. 198-203.

4. An Account of the Lymphatic System in Fish. By the same. Received June 19,

1769; read November 16, 1769. — Philosophical Transactions for the year
1769, vol. lix, pp. 204-15.

5. Experiments on the Blood, with some Remarks on its Morbid Appearances. By

William Hewson, F.R.S. Received May 17, 1770; read June 14 and 21,
1770.— Philosophical Transactions for the year 1770, vol. Ix, pp. 368-83.

6. On the Degree of Heat which Coagulates the Lymph, and the Serum of the

Blood ; with an Inquiry into the Causes of the inflammatory Crust, or Size,
as it is called. By the same. Received May 7, 1770; read November 15,
1770.— Philosophical Transactions for the year 1770, vol. Ix. pp. 384-97.

7. Further Remarks on the Properties of the Coagulable Lymph, on the Stopping

of Hemorrhages, and on the Effects of Cold upon the Blood. By the same.
Received July 7, 1770; read November 22, and December 6, 1770.— Philo-
sophical Transactions for the year 1770, vol. Ix, pp. 398-413.

1 LIST OF HEWSON'S WRITINGS.

8. On the Figure and Composition of the Red Particles of the Blood, commonly

called the Red Globules. By Mr. William Hewson, F.R.S., and Teacher of
Anatomy. Read June 17 and 24, 1773 — Philosophical Transactions, 1773,
x vol. Ixiii, pp. 303-23.

9. An Experimental Inquiry into the Properties of the Blood, with some Remarks

on its Morbid Appearances ; and an Appendix, relating to the Discovery of
the Lymphatic System in Birds, Fish, and the Animals called Amphibious.
By William Hewson, F.R.S., and Teacher of Anatomy. 12mo. Printed for
T. Cadell, in the Strand, London, 1771. A second edition, the above title
being preceded with ' EXPERIMENTAL INQUIRIES, PART THE FIRST,' was
printed in 8vo, for T. Cadell, in the Strand, London, 1772; and a third,
merely an exact reprint of the second, for J. Johnson, St. Paul's Churchyard,
London, 1780.

10. Experimental Inquiries, Part the Second, containing aDescription of the Lymphatic

System in the Human Subject, and in other Animals. Illustrated with Plates.
Together with Observations on the Lymph, and the Changes which it under-
goes in some Diseases. By William Hewson, F.R.S., and Teacher of Anatomy.
Printed for J. Johnson, No. 72, St. Paul's Churchyard, 8vo, London, 1774.

11. Experimental Inquiries, Part the Third, containing a Description of the Red

Particles of the Blood in the Human Subject and in other Animals ; with an
Account of the Structure and Offices of the Lymphatic Glands, of the Thymus
Gland, and of the Spleen ; being the remaining part of the Observations and
Experiments of the late Mr. William Hewson, F.R.S., and Teacher of Anatomy.
By Magnus Falconar, Surgeon and Teacher of Anatomy. London, printed
for T. Longman, No. 39, Paternoster Row. 8vo, 1777.

12. A Letter from the late Mr. William Hewson, F.R.S., and Teacher of Anatomy in

London, to Dr. John Haygarth, Physician in Chester. — Medical and Philo-
sophical Commentaries, by a Society in Edinburgh, vol. iii, pp. 87-93, 8vo>
London, 1775.

EXPERIMENTAL INQUIRIES.

PART I.
AN INQUIRY

THE PROPERTIES OF THE BLOOD,

REMARKS ON SOME OF ITS MORBID APPEARANCES ;

AN APPENDIX

RELATING TO THE DISCOVERT OF THE LYMPHATIC SYSTEM IN BIRDS, FISH,
AND THE ANIMALS CALLED AMPHIBIOUS.

BY WILLIAM HEWSON, F.R.S.

AND TEACHER OF ANATOMY.

LONDON :

MDCCLXXII.

Vere scire, est per causas scire.

LORD BACON.

TO

SIR JOHN PRINGLE, BAKT.,

•

PHYSICIAN TO HER MAJESTY.

SIR, — I have taken the liberty to address you upon this
occasion, not so much that I might pay a compliment to your
merit, as that I might boast of your friendship : it is im-
possible that I should add anything to your reputation by
displaying your abilities ; but you may add greatly to mine,
even by detecting my mistakes. You have done me the
honour to approve this little Essay, and I am ambitious to tell
the world that it owes much both to your knowledge and

your kindness ; which have concurred to suggest many useful

«
hints and judicious corrections, that make it more worthy of

attention, and afford me a public opportunity of assuring you
that I am, with the truest respect and esteem,

Sir,

Your most obedient,

And most obliged humble servant,

WILLIAM HEWSON.

PREFACE.

THE knowledge of the human frame, the preservation of
health, and the cure of diseases, are objects of too great im-
portance to mankind for the author of these sheets to doubt
that any attempts to promote them, how small soever, should
not meet with a candid and indulgent reception from the
public. An Inquiry into the Properties of the Blood, it is
presumed, will be thought, in a particular manner, interesting,
since there is no part of the human body upon which more
physiological reasoning is founded, nor any from which more
inferences are drawn for the cure of diseases. And, as the
Inquiry is made by Experiments upon the Blood as near as
possible to the state in which it circulates in the vessels, it is
hoped that the conclusions made from them will stand the
test of a candid examination, and lead to further observations
and improvements.

Since the publication of the first edition, some new Experi-
ments have been made, and a new chapter has been added,
which contains a recapitulation of the principal facts and con-

Ivi PREFACE.

elusions that are met with in this Essay. These additions are

between pages 61 and 82.

The Appendix is a vindication of the Author's right to the
discovery of the Lymphatic Vessels, in opposition to the claim
of the learned Dr. Alexander Monro, Professor of Anatomy in
the University of Edinburgh.

PROPERTIES OF THE BLOOD,

CHAPTER I.

OF THE SEPARATION OF THE SERUM; THE COLOUR OF THE
CRASSAMENTUM; AND OF THE CAUSES OF THE COAGULATION
OF THE BLOOD.

WHEN fresh blood is received into a basin, and suffered to
rest, in a few minutes it jellies or coagulates, and soon after
separates into two parts, distinguished by the names of crassa-
mentum and serum. These two parts differ in their propor-
tions in different constitutions : in a strong person the crassa-
mentum is in greater proportion to the serum than in a weak
one ; and the same difference is found to take place in dis-
eases ; thence is deduced the general conclusion, that the less
the quantity of serum is in proportion to the crassamentum,
bleeding, diluting liquors, and a low diet, are the more neces-
sary; whilst in some dropsies, and other diseases where the
serum is in a great, and the crassamentum in a small propor-
tion (i), bleeding and diluting would be highly improper. As

(i.) It is not easy to ascertain exactly the proportion of serum,
because, as Dr. Daviesa observed, the more the fibrin contracts the
more serum it presses out. By adding weak saline solutions or urine
to blood newly drawn, I found that the size of the crassamentum was in-
creased and the quantity of fluid separated decreased.5 Dr. Davyc has

a Essays on the Human Blood, p. 18, 8vo, b Edin. Med. & Surg. Journ. Ixiv, 369-71.
Lond. 1760. c Researches Phys. and Anat. ii, 28.

1

2 PROPERTIES OF

it is therefore supposed useful to attend to the proportions of
these parts in many disorders, and even to take indications of
cure from them, it has been an object with those who have
made experiments on the blood, to determine the circumstances
on which its more perfect separation into these two parts de-
pends ; it being obvious, that till this be done, our inferences
from their proportions will be liable to considerable fallacies.
Two of the latest writers on this subject agree, that if the
blood, after being taken from a vein, be set in a cold place,
it will not easily separate, and that a moderate warmth is ne-
cessary : this is a fact that is evinced by daily experience.

clearly shown that, in animals blooded to death, the specific gravity of
the blood which flows last is diminished, and that there is not a greater
difference in the specific gravity of the whole mass of such blood than
in the serum alone ; whence he infers that the watery part is increased
in the blood which flows last. After bleeding a man into two basins,
I have several times found the serum of the last drawn blood speci-
fically lightest.

Dr. Davy's observations'1 seem to show that in acute inflammatory
diseases the blood differs very little in specific gravity from healthy
blood, while in chronic diseases it is comparatively dilute and of low
specific gravity. And although he infers from his first table that the
proportion of animal matter is increased, and the proportion of water
diminished, still the details of his last table rather favour the conclu-
sion that there is no constant relation between the presence of the buffy
coat and the proportion of fibrin in the blood. But the old opinion of
Quesnay,6 Gaubius/ and Hey,g that the fibrin is increased in the blood
during inflammation, has been confirmed by Thackrah,h and adopted
by Dr. Benj. Babington,' Mr, Grainger, J and by later writers generally.
Mr. Wharton Jonesk and Dr. Simon observe, that there is also a dimi-
nution of the red corpuscles, which they believe are more quickly
turned into fibrin1 during inflammation than in health ; as was also the
opinion of Quesnay and Bordenave, referred to, as well as the some-
what similar notion of Sydenham, in the Introduction.

Consult, for further details on the relative proportion of the three parts
of the blood in disease, M. A»dral's 'Essai d'Hematologie Pathologique,*
8vo, Paris, 1 843 ; the observations of Becquerel, Rodier, Simon, Marchand,
Nasse, Enderlin, and others, given in the English version of Simon's
* Animal Chemistry,' published in 1845, by the Sydenham Society.

d Res. Phys. andAnat. ii, 31,34,39, 42. Blood, new ed. by Wright, p. 206-11,

e Traite de la Saignee, p. 415, 8vo, Paris, 8vo, Lond. 1834.

1750. > Cyclopaedia of Anatomy, i, 420.

f Instit. Pathol. §§ 366-7, 8vo, Leid. Bat. J Elements of General Anatomy, p. 41,

1763. 8vo. Lond. 1829.

e Obs. on the Blood, p. 21, 8vo, Lond. k Report, §§ 19,20, 21,34,35, Brit, and

1779. For. Med. Rev. No. xxxv.

h Inquiry into the Nature, &c. of the ' See Notes xvm & cxvin, and Introd.

THE BLOOD. 3

They likewise say, that the heat should be less than that of
the animal, or than 98° of Fahrenheit's thermometer; and
that, if fresh blood be received into a cup, and that cup put
into water heated to 98°, it will not separate ; nay, they even
say, that it will not coagulate ; but this, I am persuaded from
experiments, is ill founded (n).

EXPERIMENT I.

A tin vessel, containing water, was placed upon a lamp,
which kept the water in a heat that varied between 100°
and 105°. In this water was placed a phial, containing
blood that instant taken from the arm of a person in health ;
the phial was previously warmed, then filled, and corked to
exclude air. In the same water was placed a teacup half full
of blood, just taken from the same person ; a third portion of
the blood was then received from the same vein into a basin,
and was set upon a table, the heat of the atmosphere being at
67°. Now, according to their opinion, the two former should
neither have coagulated nor separated, when that in the basin
began to separate ; but, on the contrary, they were all three
found to coagulate nearly in the same time ; and those in the
warm water not only did separate as well as the other, but
even sooner.

EXPERIMENT II.

The same experiment was repeated on the blood of a person
that laboured under the acute rheumatism, whilst the heat of
the atmosphere was no higher than 55°, and that of the warm
water was 108° ; and the result of this experiment was not
only a confirmation of what was observed in the first, but it
even showed, that this degree of heat was so far from lessen-

(TI.) Dr. Butta says, that blood taken from a vein remains fluid if
kept at the heat of the living body, and that at about 32° the blood con-
cretes into an uniform mass, but does not separate. Schwenkeb has
some like erroneous observations as to the effect of heat. A moderate
warmth is not essential, though favorable, to the separation of the blood ;
it will take place at from 40°-44°. The effects of different temperatures
on coagulation are given in Notes in, xi, and xvi.

a De Spont. Sang. Sep. Sect, i, cap. ii, b Haematologia, pp. 89-90, 8vo, Hag.
4to, Edin. 1760, in Sandifort. The- Com. 1743.
saur. t. ii.

4 PROPERTIES OF

ing, that it increased the disposition to coagulate; for the
blood in the cup and in the phial was not only congealed, but
the separation was much advanced before the whole of the
blood in the basin was coagulated. Thence I am led to con-
clude, that the separation of the blood in a given time, is in
proportion as the heat in which it stands is nearer to the
animal heat, or 98° ; or greater in that heat than in any of a
less degree (m). And I am confirmed in this inference by

(in.) Mr. Hewson has clearly shown that a high temperature pro-
motes and a low one retards coagulation. Mr. Heya says, that a heat
equal to that of the living body is most favorable to the separation of
the serum and clot; and Professor Burdach,b quoting Hewson, Schrceder,
and Thackrah, asserts that this heat is most favorable to coagulation.
But it would appear to be more hastened by a higher temperature. In
Hewson' s experiments vi-ix, blood in the veins just removed from dogs,
coagulated completely at 120°- 125° in eleven minutes, remained fluid
after that time, when the heat was not raised above 114°; and when kept
at rest in the vein in the living animal was not wholly coagulated in
less than two or three and a quarter hours. Mr. Hunter0 found that
blood removed in sections of the jugular veins from dogs, and heated to
about 120°, coagulated five minutes sooner than when kept at its
natural heat ; and that the contraction of muscle was hastened by a tem-
perature of 125° and of 98°. In Mr. Thackrah's experiments/ blood
removed in the jugular veins from living dogs, did not coagulate at the
atmospheric temperature in twenty minutes, nor in an hour at 98-100° ;
and blood, in portions of the umbilical cord, detached from a living
child, and placed in water at 100-110°, was fluid and of the natural
consistence at the end of fifteen minutes, and found to contain clots after
thirty-five minutes. Of blood abstracted as usual, he believed thai a tem-
perature of 120-130° considerably hastens coagulation; and that 100-1 10°
generally does so, but in a less marked manner. Sir Charles Scudamore"
found that blood drawn from a person affected with pleurisy coagulated
quicker at 120° than at 98°. Dr. Davy's experimentsf dispose him to
infer that a heat of 120° immediately renders the blood more liquid
and accelerates coagulation ; that it is rather retarded than quickened
at 100°; more rapid at 80° or 90° than at 100°, and less so than at
120°. Mr. Hunter^ observed that a cup of blood put into water at
150° coagulated much quicker than at 48°, whence he infers that heat
acts as a stimulus upon the blood, adducing the experiment "as one of
the proofs of the living principle of the blood, where it is contrasted
with a similar experiment on living muscles." Mr. Prater11 says, that
blood is kept permanently fluid by a heat of 140-150°.

The following is a brief synopsis of my own experiments. Fahrenheit's

a Obs. on the Blood, p. 39. e On the Blood, p. 20, 8vo, Lond. 1824.

b Physiologic, tr. par Jourdan, t. vi, p. 45. f Res. Phys. and Anat. ii, 78.

c Works, ed. by Palmer, iii, 26, 110. s Works, ed. by Palmer, iii, 144.

d On the Blood, ed. 1834, Exp. 44, 45, 50, h Exp. Inq. in Chemical Physiol. Part i,
&1, 52, 56. pp. 12 et seq. & 73, 8vo, Lond. 1832.

THE BLOOD. 5

experiments hereafter to be related, where the blood in the
living animal, whilst at rest, was found both to coagulate and
to separate.

It is well known, that the crassamentum consists of two
parts, of which one gives it solidity, and is by some called the
fibrous part of the blood, or the gluten, but by others with
more propriety termed the coagulable lymph ; and of another,

thermometer, as usual, was employed. The blood experimented on
was taken from the 'jugular veins of troop horses; it was put into tubes
of thin glass, about three eighths of an inch in diameter, and then
plunged into water heated to the required degrees. Different neutral
salts were used; but most commonly half an ounce of Glauber's salt to
six ounces of blood, being the mixture mentioned by Hewson.

a. It is extremely difficult to ascertain the precise degree of heat
most favorable to the coagulation of a spontaneously coagulable fluid ;
but one cause of discordance as to the effects of higher temperatures
has arisen from different methods of experimenting. A cup of blood
put into water at 1 50°, as in Mr. Hunter's experiment, will coagulate
before acquiring that heat, whilst blood in a thin tube, in the same water,
may have its property of spontaneously coagulating quite destroyed.

b. Different portions of blood were subjected to every degree of heat,
from 139° to 151°, and in every trial the blood was fluid at the end of
twenty miuutes. It never coagulated regularly, though it did some-
times partially; and at the higher degree there was, towards the bottom
of the tube, a grumous, and sometimes a stiff" and brownish paste,
chiefly of corpuscles, leaving no fibrin behind when washed in a linen
bag. The coagulable lymph was liquid at the top of the blood in the
tube.

c. Some liquor sanguinis skimmed from fluid blood, and kept at a
heat of 139° for twenty minutes, never coagulated. Another portion
of liquor sanguinis at 148-150° was fluid at the end of twenty-three
minutes, but coagulated in twenty-eight, when it was more opaque than
a portion of the same fluid which had coagulated in the air at 60° in
fourteen minutes.

d. At a heat of 122°, 123°, 124°, 125°, and 126°, coagulation of
blood, and of liquor sanguinis separately, was hastened about two mi-
nutes, and rather more at the lower than* at the higher degrees.

e. A mixture of blood and salt, or of liquor sanguinis and salt, will
not coagulate at any degree of heat short of that which coagulates the
albumen, commencing at about 125°.

f. It is true that in salted liquor sanguinis at 124-127°, though a
great part of the mixture remains fluid, a little curdy, flaky, filamentous,
and opaque precipitate forms, which is probably what Hewson describes
in his Experiments vn and ix as coagulation ; though it differs from the
spontaneous setting or jellying into a transparent mass of a mixture of
salted liquor sanguinis and water.

g. As shown in Note xvn, serum mixed with Glauber's salt coagulates

6 PROPERTIES OF

which gives the red colour to the blood, and is called the red
globules. These two parts can be separated by washing the
crassamentum in water, the red particles dissolving in the
water, whilst the coagulable lymph remains solid. That it is
the coagulable lymph, which, by its becoming solid, gives
firmness to the crassamentum, is proved by agitating fresh
blood with a stick, so as to collect this substance on the stick,
in which case the rest of the blood remains fluid1.

The surface of the crassamentum, when not covered with a
size, is in general of a more florid red than the blood was
when first taken from the vein, whilst its bottom is of a dark
colour, or blackish. This floridness of the surface is justly
attributed by some of the more accurate observers to the air
with which it is in contact ; for, if the crassamentum be in-

1 It may be proper to mention here, that till of late the coagulable lymph has been
confounded with the serum of the blood, which contains a substance that is likewise
coagulable. But in these sheets, by the lymph, is always meant that part of the blood
which jellies, or becomes solid spontaneously when blood is received into a basin,
which the coagulable matter that is dissolved in the serum does not ; but agrees more
with the white of an egg, in remaining fluid when exposed to the air, and coagulating
when exposed to heat, or when mixed with ardent spirits, or some other chemical
substances.

at a lower heat than pure serum ; and the less water there is in serum,
or in other words, the greater the proportion of albumen, the lower is
the temperature required for its coagulation. Liquor sanguinis kept
fluid by salt is only affected by heat like a concentrated serum.

h. A fresh mixture of liquor sanguinis and salt, diluted with four or
five parts of distilled water, generally coagulates in less than twenty-five
minutes at 65°; its coagulation is hastened by any degree of heat
upwards to 123°; most so from 96° to 114°. From 124° to 127° its
power of spontaneously coagulating is completely destroyed; and its
transparency and fluidity are not lessened till the heat be raised enough
to produce the albuminous precipitate described above, at f.

i. When the red corpuscles are mixed with the salted liquor san-
guinis diluted with water, coagulation is quickened at all temperatures,
just as adding corpuscles to pure blood hastens its coagulation, as shown
in Exp. 57-63, Edin. Med. and Surg. Journ. vol. Ixiv, p. 374.

k. As coagulation is slower in the liquor sanguinis apart from the
corpuscles than with them, the retarded coagulation often observed in
buffy blood seems to be an effect, and not, as has been so commonly
supposed, a cause of the separation of the corpuscles and fibrin.

The effects of a low temperature and of freezing on the coagula-
tion of blood, and on the contractility of muscle, are mentioned in
Note xi.

THE BLOOD. 7

verted, the colours are changed, at least that which is now be-
come the upper surface assumes a more florid redness. This
difference of colour, others have endeavoured to explain from
the different proportions of the red particles, or globules as
they are called, which, say they, being in a greater proportion
at the bottom of the crassamentum, make it appear black ;
but, if inverted, the globules then settle from the surface
which is now uppermost, and that becomes redder. But this,
I think, is not probable ; for the lymph in the crassamentum
is so firmly coagulated, as to make it too dense to allow of
bodies even heavier than the red particles to gravitate through
it; for example, gold. That air has the power of changing
the colour of the blood, has been long known ; and the fol-
lowing experiment shows it very satisfactorily, and hardly
leaves room to refer the appearance to another cause (iv).

(iv.) Schwenkea entertained the error mentioned in the text, that
the heavier corpuscles sink through the clot, while the lighter ones
rise to its middle and surface.

Fracassati5 noticed the effect of air in making the clot more florid.
Harveyc admitted that the blood from an artery of a living animal is
more florid than from a vein, which he ascribed to accidental circum-
stances, for he believed that the colour of the two kinds of blood is
essentially the same. Lowerd specially proved the difference of colour,
correctly inferring from experiments that the change is effected in the
lungs, and further supporting this inference by observing that air pro-
duces just the same florid hue on the surface of the blood-clot out of
the body. Mayowe fully admitted Lower's views ; and attributed the
change of colour suffered by the blood in passing through the lungs
to its abstracting from the atmosphere a nitro-aerial spirit, many of the
properties of which, as he described them, belong to oxygen. Senacf dis-
believed that air affects the colour of the blood; he attributed the change
of colour to the more or less density and cohesion of the corpuscles,
and treated Mayow with improper contempt. Dr. William Hunter g
taught the difference of colour between arterial and venous blood.
Hallerh opposed Lower's conclusions; and even declared that he had
a hundred times assured himself, in dogs, that there is no difference of

a Haematologia, 8vo, Hagae Com. 1743, f Traite de la Structure du Cceur, torn, ii,

p. 116. pp. 86-7, ed. 1749.

b Phil. Trans. 1667, ii, 492. s MS. copy of Lectures, pp. 4-5, 4to,

c Opera om. 4to, Lond. 1766, p. 115. 1759 ; Press mark, B. i. 17, in Lib.

d De Corde et de Motu Sang. p. 170 et Med. Chir. Soc.

seq. 8vo, Lond. 1669. h Elem. Phys. Lib. vi, Sect. HI, § xvii;

e Tractatus quiiique Med. Phys. cap.viii, Primse Lin. Phys. § 155, 8vo, Gott.

p. 114, 8vo, Oxon. 1674. 1780; et Deux Mem. sur le Sang,

8vo, Lausanne, 1756, pp. 190-1.

PROPERTIES OF

EXPERIMENT III.

Having laid bare the jugular vein of a living rabbit, I tied
it up in three places ; then opening it between two of the liga-
tures, I let out the blood, and filled this part of the vein with

colour between the blood of the pulmonary artery and vein ; and though
he observed that the blood of the crural artery is brighter than that of
the vein, he denied that the difference of colour is caused by the action
of the lungs. Cigna1 refuted the error that the lower part of the blood-
clot is darkened by the sinking of the heavier and blacker corpuscles.
He gave some experimental proofs of the brightening effect of air on the
colour of the blood ; but believed that the air is not introduced through
the lungs, their chief office being, as he thought, for exhalation and to
cool the blood. Dr. PriestleyJ ascertained the correctness of Lower's
results, and that air will act on the blood through a moist membrane.
Priestley also provedk that the brightening of the blood is produced by the
oxygen only, and that carbonic acid, hydrogen, and azote, have the
contrary effect.

More recently, Dr. Stevens1 has arrived at the very different conclusion,
that the bright colour of arterial blood is caused chiefly or entirely by
the agency of the salts of the serum on the hematozine ; and that oxygen
changes the colour of blood from venous to arterial, merely by re-
moving the carbonic acid which is the cause of the dark hue of venous
blood. Dr. Turner111 fully adopts these views ; and Mr. Hoffmann0
is also favorable to them, chiefly because he found that salt alone
will render black blood florid, while air without salt will not pro-
duce the effect, as he illustrates by a bit of clot rendered dark
by distilled water. I find that the clot, darkened by washing with
water, is also made florid by sugar, though less brightly and quickly
than by the salt. Dr. Christison,0 on agitating red corpuscles and
serum of blood with atmospheric air, always found that oxygen disap-
pears while carbonic acid is formed ; but, owing to the strong solvent
power of the serum on this acid, he believed that more of it was formed"
than appeared in the residual air. In all these experiments venous
blood acquired a bright vermilion hue, and arterial blood had its florid
tint heightened. Dr. Davyp obtained the same results as to the absorp-
tion of oxygen by the blood and the consequent brightening of its colour.
But in the residual air he could detect only a trace of carbonic acid,
not exceeding one per cent. ; and none at all when, instead of common
air, pure oxygen was agitated with the blood. He observed that venous

1 Miscel. Phil. Math. Taurinensis, t. i, 4to, m Elements of Chemistry, 5th ed. p. 972,

1759; et Melanges de la Soc. Roy. 8vo, Lond. 1834.

de Turin, torn, v, 1770-3. n Lond. Med. Gaz. xi, 1833, p. 887.

J Phil. Trans. 1776, Ixvi, 239. ° Edin. Med. and Surg. Journ. xxxv,
k Exp. and Obs. on different kinds of Air, 97-100.

8vo, Birmingham, 1790, iii, 363. P Phys. and Anat. Res. ii, 138-9, 176-
1 On the Blood, p. 27, 8vo, Lond. 1832 ; 182.

Phil. Trans. 1835, p. 352, et seq.

THE BLOOD. 9

air. After letting it rest a little, till the air should become
warm, I took off the ligature which separated the air from the
blood, and then gently mixed them, and I observed that the
venous blood assumed a more florid redness, where it was in

blood when acted on by the air-pump did not acquire the arterial hue,
even when carbonic acid was abstracted ; and yet the florid tint was im-
parted to venous blood by agitating it with a mixture of oxygen and
carbonic acid gases, although the blood absorbed a much larger portion
of the latter than of the former gas.

The results of these two last experiments, as Dr. Davy remarks, are
nowise reconcilable with the theory of Dr. Stevens, but perfectly in
accordance with the older views which he controverts. Dr. C. J. B.
Williams'1 gives some experiments to prove that oxygen and the salts
produce the florid effect by causing the reflection of more light through
the colouring matter. Dr. Davy concludes that neutral salts brighten
the blood by separating the corpuscles, so that they reflect more light ;
and that water, acids, and other agents, darken the blood by altering
the form of tbe corpuscles and partially dissolving the colouring matter.
He remarks that hematozine is black only in mass, and red when re-
duced to powder, or viewed in a small portion by transmitted light.

This exactly agrees with the conclusion of Dr. Wells,' that air and
neutral salts affect tbe blood just as bright vermilion is produced from
cinnabar by subjecting it to minute mechanical division. He proves by
an ingenious experiment, that the opacity of the blood and the reflection
of light from it are increased by neutral salts. Now, if the brightening
of the blood arise simply from the action of the agents on the colouring
matter, it should suffer the same change when separated from the cor-
puscles ; but this it does not ; for although Dr. Stevens states that the
salts strike a scarlet colour with the pure black hematozine,* this effect
did not occur in several trials which I made by treating a solution of
it either with oxygen, sugar, or neutral salts. The experience of Dr.
Davy with common salt, and of Dr. Wells with air and neutral salts,
was the same ; and Mulder1 found that hematozine, separated from the
corpuscles, is not changed in colour either by oxygen, carbonic acid, or
protoxide of nitrogen. In all my experiments the red corpuscles were
reduced in size, both in breadth and thickness, by neutral salts, and in
a less degree by sugar and by oxygen ; while the first effect of water
and of carbonic acid was to swell the corpuscles and make them more
globular, though they became much smaller after the hematozine dis-
solved in the fluid. The observations of H. Nasse, Schultz, Henle,uand
of Mulder, T are in many respects similar. In short, it would appear
that it is simply to changes in the corpuscles and their state of aggre-

«> Lond. Med. Gaz. 1835, xvi, 788. Q Anatomic Generate, tr. par Jourdan,
r Phil. Trans. 1797, pp. 423-4, 418. t. i, pp. 461, 463, 471-2, 8vo, Paris,

s Phil. Trans. 1835, p. 352. 1843.

1 Chemistry of Veget. and Animal Phys. v Op. cit. p. 339 et seq.
Part ii,"p. 344.

10 PROPERTIES OF

contact with the air-bubbles, whilst in other parts it remained
of its natural colour.

There is a difference between the arterial and venous blood
in colour ; the former, is of a florid red like the surface of the
crassamentum, the latter is dark or blackish like the bottom
of the crassamentum. This change in its colour is produced
on the blood as it passes through the lungs, as we see by
opening of living animals1 ; and as a similar change is pro-
duced by air applied to blood out of the body, it is presumed
that the air in the lungs is the immediate cause of this change ;
but how it effects it, is not yet determined.

As the blood is changed to a more florid red in passing
through the lungs, or from the venous to the arterial system,
so it loses that colour again in passing from the arteries to the
veins in the extreme parts, especially when the person is in
health ; but every now and then we observe the blood in the
veins more florid than is usual, and. it likewise frequently
happens in venesection, that the blood which comes first out

1 That this change is really produced in the lungs, I am persuaded from experi-
ments, in which I have distinctly seen the blood of a more florid red in the left auricle
than it was in the right. But some authors of the greatest authority say that they
could not observe any such difference in a great number of experiments which they
made ; but this I should attribute to their having been later in opening the left auricle
after the collapsing of the lungs than I was ; for it seems probable, that whatever is
the alteration produced on the blood in its circulation through this organ, that
change cannot take place after it is collapsed.

gation that the effect of many substances on the colour of the blood is
owing.

The discordant observations as to the difference of colour between
arterial and venous blood may be partly owing to the facts observed by
Dr. Crawford^ and Dr. Davy,x that when dogs or sheep are exposed to
a temperature above 80°, the venous blood becomes more florid, and
the arterial less so, than at a temperature several degrees lower. The
brightening of arterial blood seems to depend on the quantity of oxygen
consumed in respiration, which is greatest in cold weather. Harvey
probably made many of his experiments in Italy. Dr. Davy could
perceive no difference of colour between the blood of the jugular vein
and carotid artery of a sheep in the hot months, at Malta. Mr.
Thackrah/ on bleeding a man in a warm bath, observed that the
blood from the basilic vein was scarlet.

w On Animal Heat, p. 307-8, 8vo, Lond. x Researches, ii, 140.

1788. > On the Blood, ed. 1834, p. 123.

THE BLOOD. 11

is blackish (v), and that which comes afterwards is more florid :
in such cases, the arterial blood passes into the veins without
undergoing that change which is natural to it.

Some of the neutral salts have a similar effect on the colour
of the blood to what air has, particularly nitre ; thence some
have attributed the difference of colour in the arterial and
venous blood to nitre, which they supposed was absorbed from
the air whilst in the lungs. But we know that this is a mere
hypothesis, for air contains no nitre (vi). Indeed, nitre is far
from being the only neutral salt which has this effect on the
blood, for most of them have some degree of it. In making
some experiments on this subject, I have observed a more re-
markable effect which some of the neutral salts have upon the
blood ; and that is, being mixed with it when just received
from the vein, they prevent its coagulation, or keep it fluid,
and yet, upon adding water to the mixture, it then jellies or
coagulates. Thus, if six ounces of human blood be received
from a vein upon half an ounce of true Glauber's salt reduced
to a powder, and the mixture agitated so as to make the salt
be dissolved, that blood will not coagulate on being exposed

(v.) Blood quickly becomes darker by stagnation in the living body.
In bleeding a horse, if the neck be tied up a few minutes, the first
flowing blood from the vein will be very dark coloured. Two hours
after putting two ligatures on the femoral artery of a dog, I found the
included blood as dark as that of a vein. Mr. Huntera noticed a
darkening of the arterial blood merely from the stagnation produced by
a tourniquet. At the temperature of the body changes take place very
rapidly in the blood. Its darkening from stagnation may perhaps be
owing to the conversion of a little oxygen, in contact with the red cor-
puscles, into carbonic acid.b

(YI.) Perhaps Mayow's nitro-aerial spirit, mentioned in Note iv,
may be here confounded with nitre. But when Hewson wrote, there
was an opinion current that the air in many places is impregnated with
nitre, which he correctly opposes as a mere hypothesis. The know-
ledge then possessed of the atmosphere was very vague. Oxygen, Dr.
Priestley's dephlogisticated air, was discovered by him in August 1/74,
three years after the publication of this part of Hewson's works.
Among the earlier observers on the effects of salts on the colour and
coagulation of the blood, were Dr. Freind,c J. Handley,d and Thomas
Schwenke.6

a On the Blood, Palmers ed. p. 88. d Mec. Essays on the Animal Economy,
b See Dr. Davy's Researches, ii, 210. p. 8, 8vo, Lond. 1721.

c Emmenologia, p. 160, §§ 1, 12, 13, 14, e Haematologia, pp. 106, 145 etseq. 8vo,
8vos Oxon. 1703. Hagae Com. 1743.

12 PROPERTIES OF

to the air, as it would have done without the salt ; but if to
this mixture about twice its quantity of water be added, in a
short time the whole will be jellied or coagulated, and on
shaking the jelly, the coagulum will be broken, and the part
so coagulated can be now separated as it falls to the bottom,
and proves to be the lymph.

In these mixtures of the blood with neutral salts, the red
particles readily subside, (especially if human blood be used)
and the surface of the mixture becomes clear and colourless ;
and being poured off from the red part, it is found to contain the
coagulable lymph, which can be separated by the addition of water.

I have tried most of the neutral salts, and have made a
table of their effects on the blood; but it is not necessary to
trouble the reader with it, as we do not see what use it could
be in medicine; for we must not conclude that their effects
within the body would be the same as out of it.1 Indeed,

1 The salts which keep the blood fluid hy itself, and yet allow it afterwards to jelly
on being mixed with water, are, sal Glauberi verus (sulphate of soda) ; sal digestivus
Sylvii (chloride of potassium) ', sal communis ; nitrum commune ; nitrum cubicum
(nitrate of soda) ; sal diureticus (acetate of potash) ; borax ; the salt made of vinegar
and the fossil alkali ; and the salt made with vinegar and chalk.

The following salts likewise keep the blood fluid, but do not allow it to jelly when
mixed with water : Tartarus vitriolatus (sulphate of potash) ; sal Epsomensis ; sal
ammoniacus communis; sal ammoniacus nitrosus ; sal rupillensis (tartrate of potash
and soda) : but alum, on being mixed with blood, coagulates it immediately (vn).

(vii.) Dr. Davya found that various salts and vegetable matters
which prevent or retard coagulation, commonly have their influence
destroyed by dilution with water ; and lie believes that blood kept fluid
by those agents would coagulate in every instance, if the due propor-
tion of water were added. He shows that the blood may be preserved
either liquid or viscid, by the neutral salts, for days or weeks, without
losing the power of coagulating and of contracting when properly di-
luted with water ; in the liquid state resisting putrefaction, and yet
readily yielding to it after coagulation. Some horse's blood, which I
had kept fluid with nitre for fifty-seven weeks, readily coagulated when
diluted with water.

Mr. Prater, too,b supposes that all the neutral salts only suspend co-
agulation ; and he has proved that blood which has been kept liquid,
either by Epsom salt or carbonate of potass, will coagulate after the
addition of certain proportions of water. He suggests, from a trial
with muriate of soda, that a small proportion of all the neutral salts

a Researches, ii, 101-2.

b Exp. Inq. in Chem. Phys. part i, 8vo, Lond. 1832, pp. 59, 63, 32, 128, 168, 174.

THE BLOOD. ' 13

these experiments, as well as some others, were not made so
much with a view of any immediate application to medicine,
as to determine the properties of the blood chemically; for,
having set out with a persuasion, that a more particular ac-
quaintance with the properties of this fluid was necessary be-
fore we could arrive at the knowledge of some of the animal
functions, such as the manner in which the bile and other se-
creted fluids are formed, I therefore was anxious to throw some
more light on this. subject. With this view I have made some
experiments even on living animals, being convinced that my
inquiries would not otherwise be satisfactoiy.

When blood is thus kept fluid by Glauber's salt, it still re-
tains its property of being coagulable by heat, and by other
substances as before, air excepted. This method of keeping
the blood fluid may therefore be useful, by affording an oppor-
tunity of making some experiments upon it, which we could
not otherwise do from its coagulating so soon when taken from
the vessels.

This property of one of the neutral salts has been long

will hasten coagulation, though they prevent it in greater quantity.
Dr. Simonc mentions, quoting Hamburger, that carbonates and acetates,
in all degrees of concentration, prevent the coagulation of the blood ;
while the sulphates, tartrates and borates, in strong solution retard
and in weak solution accelerate coagulation. In ray experiments'1 with
solutions of common salt, five and ten grains to an ounce of water, co-
agulation was somewhat retarded, but most so by the weaker solution ;
and an ounce of mucilage, having either five or ten grains of salt dis-
solved in it, likewise retarded coagulation, though less so than the mu-
cilage without the salt. The contraction of the clot was generally much
diminished by the aqueous saline solutions, but not by the mucilaginous
saline solutions. Mr. Prater observed that either a saturated or a very
weak solution of common salt, prevents the contraction of a portion of
muscle removed from an animal just killed, and that the addition of
water does not restore the contractile property. Mr. Ancelle has given
a copious table of the effects of various substances on the coagulation
of the blood.

The effect of neutral salts in preserving the fluidity of the blood is
probably dependent on the solvent power, which M. Denisf has shown
them to possess over the fibrin. But this requires further inquiry.8

c Animal Chem. i, 116, tr. by Dr. Day, e Lectures on the Blood, Lancet, vol. i,
8vo, Lond. 1845. 1839-40, p. 522.

d Edin. Med. and Surg. Jouru. vol. Ixiv, f Essai sur le Sang, 8vo, Paris, 1838,
370. Exp. 20-28. pp. 71-2.

" See Notes LVI, xu, XLIV, xvm.

14 PROPERTIES OF

known amongst those whose who prepare the blood of cattle
for food ; for it has long been a practice with such people, to
receive it into a vessel containing some common salt, and to
agitate it as fast as it falls, by which means the coagulation is
prevented, and the blood remains so fluid as to pass through a
strainer, without leaving any coagulum behind : by this means
they have an opportunity of mixing it with other substances
for culinary purposes.

Although the coagulable lymph so readily becomes solid
when exposed to the air, yet whilst circulating it is far from
that consistence: it has indeed been supposed to be fibrous (vin),
even whilst moving in the blood-vessels, but erroneously.

(vin.) It was a question in Haller's time and before, whether the
coagulable lymph be fibrous in the circulating blood. a And, notwith-
standing the evidence to the contrary, referred to in the Introduction,
Dr. Buchananb has lately published some interesting observations, to
show that the fibrin is not dissolved in the animal fluids, " but exists,
while yet within the body, already solidified, and organized in the form
of granules and vesicles ; and that the process of coagulation consists
simply in the aggregation of these minute granules and vesicles into a
mass visible to the naked eye." Unquestionably, minute molecules and
pale primary cells which floated in the fluid blood, are included in the
fibrinous clot ; but the delicate fibrils, which I have depicted0 as con-
stituting the bulk of such clots, do not appear to be formed of particles
before visible by the aid of the microscope in fluid blood, or in the
liquor sanguinis apart from the red corpuscles. Besides, similar fibrils
may be instantly produced by chemical action in certain fluids. d In
the clot spontaneously formed in a mixture of two varieties of perfectly
transparent serum, mentioned in Notes xvui and cxvin, I have dis-
tinctly seen the fibrils ; whilst they were not visible in the stiff, homo-
geneous, hyaline coagulum, formed after adding water to a fluid mix-
ture of a neutral salt and coagulable lymph, unless occasionally when
the mixture had been much more diluted before coagulation.

What is the proof that the fibrils of fibrin may not be the primordial
ones of some animal textures ? And, as mentioned more fully in the
f Philosophical Magazine' cited below,c I know not how this setting
of fibrin into fibrils can be reconciled with M. Schwann's theory,6 that
all fibres arise from a transformation of cells ; or with Dr. Martin
Barry's/ that the origin of the fibrils is from the interior of the blood-

a Elem. Phys. torn, ii, 68-70 ; Senac, Edin. Med. and Surg. Journ. vol. Ix,

Traite du Coeur, ed. 1749, ii, 102-3. p. 161 ; and Mr. Addison, Trans.

b Proc. Glasgow Phil. Soc. No. 7. Prov. Med. and Surg. Ass. vol. xii,

c Gerber's Anat. 8vo, Lond. 1842, pi. 28 ; 249-50.

and Lond. & Edin. Phil. Mag. S. 3, e Wagner's Physiol. tr. by Dr. Willis,

vol. xxi, 1842, pp. 242-4. p. 222.

d Gruby, Morphologia Fluidorum, 8vo, f Phil. Trans. 1842, p. 90.

Vindobonae, 1840, tab. 5, fig. 83;

THE BLOOD. 15

It is this coagulable lymph which forms the inflammatory
crust, or buff, as it is called. It likewise forms polypi of the
heart, and sometimes fills up the cavities of aneurisms, and
plugs up the extremities of divided arteries. It is supposed,
by its becoming solid in the body, to occasion obstructions
and inflammations ; and even mortifications, from the exposi-
tion to cold, have been attributed to its coagulation. In a
word, this lymph is supposed to have so great a share in the
cause of several diseases, that it would be a desirable matter to
be able to ascertain the causes of that coagulation, either in
the body, or out of it.

The blood, when received into a basin, and suffered to rest
in the common heat of the atmosphere, very soon jellies or
coagulates ; the part which now becomes solid is the coagulable
lymph, as has been shown above. The circumstances in which
it now differs from what it was in the veins, are these : it is
exposed to the air, to cold, and is at rest ; for whilst in the
body, air is excluded, it is there of a considerable warmth,
and is always in motion. The question is, to which of these
circumstances its coagulation whilst in the basin is chiefly
owing? This question, I believe, cannot well be answered
from the experiments that have hitherto been made. It has
indeed been said, that the cold alone coagulated it; for, say
they, if you receive blood into a basin, and set that basin
in warm water, and stir the blood well, it can be kept fluid.
But in the experiments from which this conclusion was made,
I find there has been a deception1. In short, I have found that
it coagulates as soon when kept warm and when agitated (ix),

1 That is, the lymph really had been coagulated, but by the agitation had likewise
been separated from the rest of the blood, and had thereby escaped notice.

discs. Fibrin undergoes modifications in its chemical properties after its
separation from the blood, being especially less susceptible of the action
of acetic acid, as mentioned in the Note to Gerber's Anatomy, p. 95.

A notice is given in the Introduction, of the incorrect views of Sir
E. Home and others ; as well as of the singular claim of M. Denis to
the discovery of the liquidity of the fibrin in the 'Circulating blood.

(ix.) The opinion that agitation prevents coagulation was entertained
by Lower/ and stated as a well-known fact 159 years afterwards, by
Dr. Bostock.5 Senacc adduced the supposed fact as a proof of the

a De Corde, 8vo, Lond. 1669, p. 173.

b Elementary System of Physiol. i, 438, 440, 2d ed. 8vo, Lond. 1828.

c Traite du Cceur, ed. 1749, ii, 134.

16 PROPERTIES OF

as it does when suffered to rest and to cool. As the subject
seemed to me of importance, I have endeavoured to ascertain
the circumstance to which this coagulation is owing by several
experiments, in each of which the blood was generally exposed
to but one of the suspected causes at a time. Thus, in order
to see whether the blood's coagulation out of the body was
owing to its being at rest, I made the following experiment :

EXPERIMENT IV.

Having laid bare the jugular vein of a living dog, I made a
ligature upon it in two places, so that the blood was at rest
between the ligatures ; then covering the vein with the skin,
to prevent its cooling, I left it in this situation. From several
experiments made in this way, I found in general, that after
being at rest for ten minutes, the blood continued fluid ; nay,
that after being at rest for three hours and a quarter, above
two thirds of it were still fluid, though it coagulated after-
wards. Now the blood, when taken from a vein of the same
animal, was completely jellied in about seven minutes. The
coagulation therefore of the blood in the basin, and of that
which is merely at rest (x), are so different, that rest alone

power of the action of the blood-vessels in keeping the blood fluid.
Mr. Hewson's conclusion accords with that now proved to be correct.
Mr. Hunterd states that coagulation is hastened by shaking the blood in
a phial, with or without the exclusion of air. Mr. Thackrah,e Dr. Davy/
Sir Charles Scudamore,g and Mr. Prater, h have proved that even violent
shaking of the blood does not prevent coagulation, but merely separates
the fibrin into small fragments, which may be collected on a filter ; and
that moderate agitation rather hastens coagulation.

The effect of rest on coagulation is mentioned in Note x, and of
heat in Notes in and xvi.

(x.) The effect of living tissues in retarding coagulation is mentioned
in Note xin. Mere rest has no effect whatever on the coagulation of
fibrin. In cases of empyema, I have thrice seen the matter, compressing
and condensing the lung and depressing the diaphragm, coagulate spon-
taneously when set aside in jars, although it was fluid many hours after
death, and must have been in a state of comparative repose during
life, for the matter completely filled the cavity. Blood sometimes
remains fluid and in complete rest for several hours after death,
and yet coagulates readily on exposure, as in Mr. Hewson's Exp. xvi.

d Works, ed. by Palmer, iii, 31. * Essay on the Blood, 8vo, Lond. 1824,

e On the Blood, p. 68, ed. 1834. p. 40.

f Researches, ii, 65. h Exp. Inq. in Chem. Phys. Part I, 17.

THE BLOOD. 17

cannot be supposed to be the cause of the coagulation out of
the body.

To see the effects of cold on the blood, I made this experi-
ment :

EXPERIMENT V.

I killed a rabbit, and immediately cut out one of its jugular
veins, proper ligatures being previously made upon it ; I then
threw the vein into a solution of sal ammoniac and snow, in
which the mercury stood at the 14th degree of Fahrenheit^
thermometer. »As soon as the blood was frozen and converted
into ice, I took the vein out again, and put it into lukewarm
water till it thawed and became soft ; I then opened the vein,
received the blood into a teacup, and observed that it was
perfectly fluid, and in a few minutes it jellied or coagulated as
blood usually does. Now, as in this experiment the blood
was frozen and thawed again without being coagulated, it is
evident that the coagulation of the blood out of the body is
not solely owing to cold (xi) any more than it is to rest.

In the heart of a man fifteen hours after death, when the limbs were
stiffened, I have seen fluid blood which coagulated after exposure.
Dr. Davyc has made several exact observations to the same effect, one
twenty-nine and several twenty-six hours after death. Dr. B. G.
Babingtond has recorded an instance of the same kind in bloody
fluid from the brain. Occasionally blood is extravasated and stag-
nated in the living body for an indefinite time, and yet retains
its fluidity, as Mr. Hunter6 and Mr. Caesar Hawkins have noticed.
I saw a case in a soldier who had received a bruise in his loins, from
his horse bolting with him over a bridge in Hyde Park ; the injured
part quickly swelled, evidently from effused fluid, which was let out
twenty-eight days afterwards. It measured five ounces ; was as liquid
as blood just drawn from a vein, and coagulated in a cup in less than
thirty minutes. The corpuscles were observed to be unchanged, and
readily collecting together in the usual way by their broad surfaces ;
next day, the clot was moderately firm, scarlet at the top, somewhat
contracted, and surrounded by a little serum.

The effect of agitation on coagulation is mentioned in Note ix.

(xi.) Aristotle,a Harvey,b and Sydenham,c/ attributed the coagulation
of the blood to the escape of its native animal heat or to the cold of the

c Researches, ii, 206, 122. b De Gener. Animal, p. 404, Op. ora. a

d Cyclopaedia of Anatomy, i, 421. Coll. Med. Lond. edit. 4to, 1766.

e Works, ed. by Palmer, iii, 33. c' Op. omnia, imp. Soc. Sydenhamianae,

a De Part. Animal, lib. ii, c. 4. 8vo, Lond. 1844, p. 247.

2

18 PROPERTIES OF

Next, to see the effects of air upon the blood, I tried as
follows :

EXPERIMENT VI.

Having laid bare the jugular vein of a living rabbit, I tied
it up in three places, and then opened it between two of the

atmosphere. Fourcroyd stated that caloric contributes to the fluidity
of the blood, which becomes concrete in cooling. Gaubius6 concluded
that the fluidity of the blood is preserved by the heat and motion of the
living body. Mr. Hewson's conclusions, that cold, so far from being
the cause of coagulation, actually retards it, and that it may be sus-
pended by freezing the blood and restored by thawing it, are now well
established. Senacf had noticed that the blood of fishes in winter
cannot be kept fluid by heat ; and Mr. Hunterg states that he observed,
offBelleisle, in 1761, the blood of a fish, at a temperature about 60°,
immediately coagulate on being let out of the animal into the atmos-
phere at 70°. Mr. Hey,h Mr. Thackrah,1 Sir Charles Scudamore,J and
Dr. Davy,k all ascertained that a low temperature retards coagulation.
Thackrah found that human blood remains liquid upwards of sixteen mi-
nutes at 45°, and freezes at a temperature between 20° and 30°. Dr.
Davy has seen blood remain fluid for more than an hour at 32°, and not
freezing until reduced some degrees lower; and he informs me that he has
seen the trout active in water in which ground-ice was forming at 32°. As
mentioned in Note in, he infers that a heat of 120°, which hastens the
coagulation of the blood, first makes it thinner and more liquid; and
he agrees with Mr. Hewson, that a low temperature, which retards
coagulation, renders the blood more viscid.

Mr. Hunter1 froze some blood rapidly by subjecting it to a cold
below zero ; after thawing the blood, it became fluid, and then coagulated,
he believed as quickly as if it had not been frozen. He found that
portions of muscle removed instantly from a live frog, and from a
bullock just knocked down, contracted after having been frozen and
thawed in the same manner, though irritation did not produce any
sensible motion in the fibres. "This," he says, "is exactly similar to
the freezing of blood too fast for its coagulation, which, when thawed,
does afterwards coagulate, as it depends in each on the life of the part
not being destroyed." And he observed that a high temperature acts
alike as an excitement to the coagulation of blood and to the contraction
of muscle, " both apparently depending on the same principle, namely,
life." Although Hunter never saw the life of a whole animal, which
had been frozen, return by thawing, Dr. Davym has shown that the

d Journal de Physique, 4to, Paris, 1749, h Obs. on the Blood, 8vo,Lond. 1779, p.34.

torn, xliv, p. 382. * On the Blood, ed. 1834, p. 67.

e Institutiones Pathologise, § 336, 8vo, J Essay on the Blood, p. 21.

Leid. Batav. 1758. k Researches, ii, 75.

f Traite du Cceur, ii, 133, ed. 1749. 1 Works, ed. by Palmer, iii, pp. 109-13.

* Works, ed. by Palmer, iii, 26. ™ Researches, vol. 2, p. 121.

THE BLOOD. 19

ligatures, and emptied that part of its blood. I next blew
warm air into the empty vein, and put another ligature upon
it, and letting it rest till I thought the air had acquired the
same degree of heat as the blood, I then removed the inter-
mediate ligature, and mixed the air with the blood. The air
immediately made the blood florid, where it was in contact
with it, as could be seen through the coats of the vein. In a
quarter of an hour I opened the vein, and found the blood
entirely coagulated; and as the blood 'could not in this time
have been completely congealed by rest alone, the air was
probably the cause of its coagulation.

From comparing these experiments, may we not venture to
conclude, that the air (xn) is a strong coagulant of the blood,

common medicinal leech may be restored to life after having been com-
pletely frozen ; Lister, Bonnet, and others" have observed the same fact
in the larvae of insects ; and Hudolphi,0 in the Filaria capsularia.

Dr. Davy has proved that the blood of a fowl may be thrice rapidly
frozen and thawed, and yet retain its coagulating power. He also froze
some human venous blood, which coagulated in about eight minutes
after it was gradually and completely thawed ; and on the following
day there was a distinct separation of serum from the clot. The results
obtained by Mr. Thackrahp to the contrary, are of no weight against
the mass of positive testimony above quoted. Mr. Hewson states at
pp. 25-26 how he varied his experiments on the freezing of blood.

The effects of a high temperature in hastening the coagulation of blood
and the contractien of muscle are mentioned in Notes in and xvi.

(xu.) It follows directly from Mr. Hewson's experiments, that
though air may promote, it is not the cause of the coagulation of the
blood. This lie knew ; for he observed that it coagulates when kept at
rest in the veins of living dogs and rabbits, in the sacs of aneurisms,
audin the heart and blood-vessels after death; while, in some of his ex-
periments, he found that blood when less exposed to the air coagulated
sooner than when more exposed, which he ascribed to the retarding in-
fluence of cold on coagulation. It has long been known that air may
be gradually introduced into the veins of living animals without any ill
effect.* Sproegel,b after killing dogs by blowing air into the veins,
states that the blood was fluid, even more' so than natural, contrary to
the assertion which some persons had made that it is coagulated ; and

n Carpenter's Gen. and Comp. Pliys. p. searches dePhysiol. 8 vo, Paris, 1811,

1/5, 8vo, Lond. 1841. p. 34 ; Majendie, Physiol. tr. by Mil-

0 Entoz. Hist. Nat. 8vo, Amstel. 1809, ligan, 4th ed. 8vo, Edin. 1831, p. 445.
ii, 62. b Exp. circa varia venena in vivis ani-

p On the Blood, ed. 1834, pp. 37, 67, 68. malibus inst. § xliii, Gott. 1753, in

a Haller, in Boerhaav. Prelect. Acad. 8vo, Haller. Disputat. ad Morb. t. vi, 4to,

Gott. 1740, ii, 108; Nysten, Re- Lausan. 1758.

20 PROPERTIES OF

and that to this its coagulation when taken from the veins is
chiefly owing, and not to cold, nor to rest ?

But although it appears from these experiments that the
coagulation of the blood in the basin is owing to the air alone ;

Thackrah,c in similar experiments, in which the air was well mixed with
the blood, says that it either remained fluid or had its coagulation re-
tarded ; but these conclusions require further examination.

Mr. Hunter's statement/ that blood coagulates more readily in vacuo
than in the open air, is negatived by Dr. Davy's experiments,6 from
which it results that the rate of coagulating is much the same under the
exhausted receiver as in the atmosphere, certainly not quicker, but
rather slower, which he suggests may be owing to the cooling effect of
exhaustion. From the experiments of Sir Astley Cooper and Mr.
Thackrah/ it appears that blood, when removed from living dogs in
such a manner as to cut off all communication with the atmosphere,
coagulates in ten or fifteen minutes. In some similar experiments
which I made, coagulation was generally, but not invariably, slower
than in blood received through the air into a tube. Exclusion of air
then from the blood, merely retards coagulation ; and this agrees with
the observations of Dr. Babingtong and Dr. Davyh on the coagulation
of blood covered with oil.

It results from Sir Humphrey Davy's experiments/ that coagulation
is neither materially hastened nor retarded by nitrogen, nitrous gas,
common air, oxygen, nitrous oxide, carbonic acid, or hydrocarbon.
Dr. Davy's observations^ on the effect of carbonic acid and of oxygen
are similar. Neither the cause of the coagulation of the blood, nor of
its fluidity in the living animal, is yet known. All that has been clearly
determined is, that certain conditions or substances either hasten or
retard, suspend or prevent coagulation ; and some of them would appear
to have directly opposite effects in different proportions, as noticed in
Note vn.

The causes usually given, on the authority of Mr. Hunter, k as alto-
gether destroying the coagulable property of blood and the contractility
of muscle, are some of them so doubtful that they all require to be ex-
amined anew. Thus, in a man killed by lightning, Dr. Davy1 observed
some soft coagulum in the heart, and that the fingers were rigid, al-
though the examination was not made until the body was rather ad-
vanced in putrefaction. Sir Charles Scudamore™ invariably found the
blood coagulated as usual in animals killed by electricity. Sir B. Brodie n

c On the Blood, pp. 76-7, ed. 1834. J Researches, ii, 86.

d Works, ed. by Palmer, iii, 27. k Works, ed. by Palmer, iii, 34, 1 14.

e Researches, ii, 89. i Researches, ii, 71.

f On the Blood, pp. 77, 83, ed. 1834. m Essay on the Blood, p. 126, 8vo, Lond.
s Med. Chir. Trans, xvi, 298. 1824.

h Researches, ii, 90. n Lectures on Pathology and Surgery,
* Res. on Nitrous Oxide, 8vo> Lond. 8vo, Lond. 1846, p. 102.

1800, pp. 380-1.

THE BLOOD. 21

for cold lias no such effect, nor has rest in a sufficient degree,
because the coagulation of the blood in the basin takes place
in a few minutes, whilst that which is merely at rest in the
veins is not completely coagulated in three hours or more.
Yet the blood is in time completely coagulated merely by its
being at rest in the veins ; but then in this case it coagulates
in a different manner from what it does in the basin ; and as

found that the irritability of the muscular fibre was not destroyed in a
guinea-pig which had been instantly killed by an electric shock.

Dr. Andrew Smith0 commonly saw coagulated blood in the hearts of
antelopes run down by dogs. In a hunted hare Dr. Davy saw, he in-
forms me, some coagulated blood. So jdid I in one that had been run
for thirty-five minutes and then killed by the Windsor harriers ; it was
immediately gutted, and I examined it four hours afterwards. After
pressing blood into the jugular veins, portions of them were removed
and laid aside with the contained blood ; it never coagulated. There
were some small but distinct clots in both ventricles of the heart, all
the cavities of which were otherwise empty. In the left pleura there
was upwards of a quarter of an ounce of thick yet fluid blood, which
never clotted; but in which, when mixed with water and filtered, some
small fibrinous flakes were found. The heart was hard and contracted ;
the limbs, especially the hind ones, were quite rigid. Besides, I have
been assured by old' and observant sportsmen, that when a fox has been
run very hard he stiffens quickly, in the hind limbs especially, so that
you may hold out his body by them horizontally. Finally, as to a blow
on the stomach : In a cat killed by a kick, which ruptured the stomach
and liver, 1 found coagulated blood in the heart, and the limbs rigid,
seventeen hours after death. Some cases in which the blood did not
coagulate after death are mentioned in Note xxxiu.

Mr. Hunter,p conceiving coagulation to be an act of life, maintained
that the blood coagulates by virtue of its living principle. If we admit
this hypothesis, we must also admit that we can pickle the life (see
Note vn) ; that it is preserved after repeated freezing and thawing (see
Note xi) ; and, as Dr. Davy remarks,*1 that the blood may remain alive
many hours after the death of the body, when the muscular fibre has
lost its irritability, the limbs have stiffened, and even partial decompo-
sition has begun (see Note x). Besides, a mixture of two varieties of
perfectly clear serum will coagulate spontaneously, as I have witnessed
after filtering them four days after they were drawn from the living human
body (see Note xvin)'; and M. Denisr states that fibrin may be dried
and powdered, and yet possess the power of self-coagulation when
dissolved in a neutral saljt and diluted with water.

0 J. Davy's Researches, ii, p. 74. r Essai sur 1' Application de la Chimie a
P Works, ed. by Palmer, iii, pp. 34, 113. 1'Etudie physiologique du Sang de

1 Researches, ii, 122. 1'Homme, p. 72, 8vo, Paris, 1833.

22 PROPERTIES OF

it probably is in this way that the blood is coagulated in the
body, I have been more particularly attentive to it, and have
endeavoured to determine by experiment how it takes place.
With this view I have several times repeated Experiment the
Fourth, which was made with a view to determine whether the
blood would coagulate by -rest. In the first trial, the vein
was not opened till the end of three hours and a quarter ; and
just before it was opened I had observed through its coats, that
the upper part of the blood was transparent, owing to the separa-
tion of the lymph. On letting out this blood, it seemed to me
entirely fluid : a part indeed had been lost, but the greatest part
was collected in the cup, and which afterwards coagulated as
blood commonly does when exposed to the air. From this
experiment I imagined that the whole had been fluid ; but
from others made since, I am persuaded that the part which
was lost had been coagulated ; for, from a variety of trials, I
now find, that though the whole of the blood is not congealed
in this time by rest alone, yet a part of it is. But as it would
be trespassing too much on the reader's time to relate every
experiment I have been obliged to make for this purpose, I
shall only mention the general result of the whole.

After fixing a dog down to a table, and tying up his jugular
veins, I have in general found that on opening them at the
end of ten minutes, the blood was still entirely fluid, or with-
out any appearance of coagulation.1 If they were opened at
the end of fifteen minutes, at first sight it also appeared quite
fluid; but on a careful examination I found sometimes one,
and sometimes two or three small particles about the size of a
pin's head, which were coagulated parts of the blood. When
opened later than this period, a larger and larger coagulum
was observed; but so very slowly does this coagulation pro-
ceed, that in an experiment where I had the curiosity to com-
pare more exactly the clotted part with the unclotted, I found,
after the vein had been tied two hours and a quarter, that the
coagulum weighed only two grains ; whilst the rest of the
blood, which was fluid, on being suffered to congeal, weighed

1 I say in general it was fluid at the end of ten minutes ; but I must likewise
mention that in one dog I found two very small particles of beginning coagulation,
even at this period ; yet in another I could not observe any such appearance, even at
the end of fifteen minutes.

THE BLOOD. 23

eleven grains. I can advance nothing farther in this part of
my subject with precision. Nor can I pretend exactly to de-
termine the time at which all the blood between the ligatures
is coagulated^ I have indeed opened such a vein at the end
of three days, when I foun A a thin white coagulum, which was
a mere film ; the serum and red particles having disappeared.
But the whole is undoubtedly congealed long before this period.
The manner in which the blood coagulates, when at rest in
the body, has appeared to me curious, and therefore I have
taken the more pains to discover how it happens, especially as
it may assist us in judging whether or no it coagulates in the
heart, so as to form those substances called polypi (xin). The

(xin.) Blood generally coagulates much more slowly in contact with
the living parts than when removed from them, an effect which Mr.
Thackraha ascribes, I believe hypothetically, to the influence of the
nerves in keeping the blood fluid. Mr. Hunter5 noticed that the con-
tact of blood with living vessels retards its coagulation. In the ex-
periments of Sir Astley Cooper and Mr. Thackrahc blood kept at rest
in a living vein did not coagulate in an hour, while blood similarly con-
fined in a dead vein, excluding air, was firmly concreted in a quarter of
that time ; and blood from the same dogs, cats, and rabbits, used in
Mr. Thackrah's experiments, began to coagulate in from two to four
minutes when abstracted and set apart in the usual manner.

I made some experiments at Chatham, in August, 1837, on the coagu-
lation of blood confined in the jugular veins of living dogs, disturbing
the parts no more than was necessary to apply the ligatures. Twice
only, out of many trials, were small clots observed as early as two hours
after the operation. Coagulation generally did not commence before
the expiration of three hours ; half an hour later there was com-
monly a central clot about one fourth the size of the imprisoned
blood ; and the remaining three fourths coagulated in two, six, and
seven minutes, in three different instances, when received into a watch-
glass. In one trial, the confined blood was wholly fluid at the end
of five hours ; in another, after seven hours, the clot was no larger
than that just mentioned, and the fluid part of the blood coagulated on
exposure in five minutes. In nine hours the blood was completely co-
agulated in the right vein of one dog, and only partially so in the left
vein of another ; and the fluid portion concreted when exposed in less
than eleven minutes. After eighteen hours, in two trials the blood was
about half coagulated, and in a third, completely so. At the end of
twenty -four hours, coagulation was complete in four trials, and incom-
plete in one.

The pale masses of fibrin called polypi are formed in the heart after

* On the Blood, ed. 1834, pp. 80, 91. c On the Blood, ed. 1834, p. 85; and
b Works, ed. by Palmer, iii, 29. Prater, p. 21.

24 PROPERTIES OF

above-mentioned times will, I believe, be found to be those at
which the blood congeals in the veins of healthy dogs : and as
I have found, by experiments, that the blood of a dog and of
the human subject in "health jellies out of the body, nearly in
the same time, that is, it begins in three or four minutes, and
is completed in seven or eight ; I should therefore conclude
that the blood in the veins of the human body coagulates
nearly at the same period with that of a dog (xiv). But it
may be necessary to add here that, from experiments which I
have made, I have reason to believe that the* time at which
the blood coagulates, is different in different constitutions, and

death, the sinking of the corpuscles being favoured by their increased
tendency to aggregation in connexion with disease, and by the slowness
with which the blood coagulates (see Notes x and xxin). Mr. Pagetd
has shown that the disposition of the parts of the blood in the dead body
is the same as if the blood had coagulated as slowly and separated in a
basin ; and that the clot is so regularly pale in its upper part, and coloured
by the red corpuscles at the bottom, that the fact might be available in
medico-legal inquiries as to the position of the body in the first hours
after death. But the separation of the corpuscles is often imperfect, or
does not take place at all, as I have witnessed in some cases of sudden
death. Dr. Davy6 found the clot broken up in the ventricles, as if its
coagulation had preceded death. The relative position of the fibrin
and coloured matter in the heart and great vessels after death, did not
escape the notice of the accurate Petit. f

Fibrinous clots are occasionally formed in the heart and blood-vessels,
and become softened there, during life. The softening is generally,
but not always, in the centre of the clot. Coagulation of blood in the
veins, often followed by softening of the clot, is a common disease
in the human subject, especially in connexion with oedema of the lower
limbs. This softening of fibrin is very frequent in the veins of horses.
It does not appear to be of an inflammatory nature, though I apprehend
that it has been generally confounded with phlebitis. g

(xiv.) I have found that the blood of a dog generally coagulates
rather sooner than that of man. Mr. Thackraha infers from his ex-
periments that coagulation commences sooner in the blood of small and
weak animals than in that of the large and strong. Dr. Blundellb states
that the blood of the dog, sheep, and ox, coagulates sooner than the
human blood.

<* Lond. Med. Gaz. i, 1840-1, p. 613. s On the Softening of Fibrin, Med. Chir.
e Researches, ii, 196. Trans, vol. xxii.

fHist. de 1'Acad. Roy. des Sciences, a On the Blood, ed. 1834, p. 154.

annee 1732, p. 393. h Med. Chir. Trans, ix, 67.

THE BLOOD. 25

in different diseases. For though the blood of a person in
health is completely coagulated in seven minutes after it is
taken out of the veins, yet in some diseases, I have found the
blood fifteen or twenty minutes, nay, even an hour and a half,
before it was completely jellied.

As we see in the above-related experiments, that the blood
coagulates in the body when suffered to rest for a little time,
is it not probable that to this cause its coagulation in those
true aneurisms, which are attended with a pouch, are owing ?l
For in such enlargements a part of the blood is without mo-
tion, which will congeal when at rest, and in contact with the
sac ; and thus one layer may be formed ; and the sac afterwards
enlarging, another portion of the blood will then be at rest ;
and so a second layer may be formed ; and thence probably is
the origin of those laminated coagula met with in such sacs.

Likewise, to the blood's being at rest, is probably owing its
coagulation in the large arteries which are tied after amputa-
tion, or other operations ; for after most of such ligatures there
will be a part of the artery impervious, in which the blood can
have no motion. The coagulum after amputation might in-
deed be supposed owing to air ; but, considering the manner
in which arteries are tied whilst the blood is running from
them, it does not seem probable that the air has any effect on
what is above the ligature.

To the blood's being without motion in the cavity of the
uterus, is its coagulation th'erein probably owing; hence the
origin of those large clots which sometimes come from that
cavity ; and which, when more condensed by oozing out of the
serum, and of the red globules, assume a flesh-like appearance,
and have often been called moles or false conceptions.

In Experiment the Fifth, we found that the blood could be
frozen and thawed again, without being coagulated : this like-
wise is an experiment which I have repeated .several times,
that I might be sure of the fact. I have also varied the experi-
ment by sometimes putting the vein into a phial of water, and
freezing the whole in a solution of sal ammoniac in snow; and
sometimes I have put the vein into the solution itself; and

1 An instance of which may be seen in the Med. Obs. and Inq. vol. i, article xxvii,
fig. iii.

26 PROPERTIES OF

three or four times I have thrown it into oil, and then frozen
it; but after all these trials, the result was the same (xv).
The blood was always evidently fluid on being thawed, and as
evidently jellied when exposed to the air.

Besides being coagulated when exposed to the air, the co-
agulable lymph, as well as the serum, is known to be fixed by
heat ; but the degree of heat has not, so far as I know, been
determined. It has been supposed to require a degree almost
equal to that which cpagulates the serum ;x but one much less
is necessary, as will appear from the following experiments.

EXPERIMENT VII.

Having found, from a number of trials, that blood, kept
fluid by means of true Glauber's salt, had its lymph coagulated
by a heat of 125° of Fahrenheit's thermometer, I supposed
that the degree necessary for fixing it in its natural state could
not be very different from this. I therefore prepared a lamp
furnace with a small vessel of water upon it ; this water was
heated to 125°; and then laying bare the jugular vein of a
living dog, I tied it properly, cut a piece of it out, and put it
into this water : after eleven minutes, I took out the vein, opened
it, and found the blood entirely coagulated : thence I concluded,
that 125°, or less, was sufficient to coagulate the blood of a
dog. It may be necessary to observe here, that the part coagu-
lated was only the lymph ; for the serum requires a much greater
heat to fix it, that is, a heat of 160°, as will appear hereafter.

EXPERIMENT VIII.

The same experiment was repeated in such a manner, that
the heat never went higher than 120i° ; and I found that, on
opening the vein at the end of eleven minutes, the lymph
was entirely coagulated, even in this heat.

EXPERIMENT IX.

I repeated the experiment with a heat no higher than 114°,
and at the end of eleven minutes, the vein being opened, the

1 See Traite du Cceur, t. ii, p. 93 ; Schwenke Hsematolog. p. 138.

(xv.) See Note xi, where the effects of cold and of freezing on coagu-
lation are detailed.

THE BLOOD. 27

blood was found to be fluid, and in a few minutes after, being
laid open to the air, it coagulated as usual. Now, as the blood
in the last experiment was coagulated, when the heat had
never risen above 1201°; and in this experiment was fluid, though
it had been exposed to a heat of 114°; we may therefore con-
clude that the coagulable lymph in the blood of a dog in health
is fixed in a degree of heat between 114° and 120±° of Fahren-
heit's thermometer.

As to the degree of heat at which the lymph in human blood
coagulates, I have not yet had an opportunity of trying it in a
more satisfactory way, than with the mixture with Glauber's
salt, in which state it coagulates at 125°. But, as we find
that the human blood and that of a dog jelly nearly in the
same time, when exposed to the air, I think it probable that
the precise degree of heat at which the lymph of the human
blood coagulates, is between 114° and 120^° (xvi). I have
thought of making the experiment on the umbilical cord of a
recent placenta, which perhaps is the most likely way of coming
at the truth.

The degree of heat, at which the serum of the blood (which
should not be confounded with the lymph) coagulates, is ge-
nerally said to be 150° ; but from my experiments I am inclined
to believe it requires a greater heat to fix it. They were made
in the following manner :

(xvi.) In my experiments, mentioned in Note in, a mixture of
liquor sanguinis and a neutral salt appeared to be affected by heat only
like a very concentrated solution of albumen. When diluted with water,
and kept at a heat of 125° or 126°, there was no precipitation of al-
bumen ; but the self-coagulating power of the mixture was com-
pletely destroyed. These results agree essentially with those of
Mr. Prater. a The heat of some animals approaches 1 14°. In some
healthy birds at Ceylon, Dr. Davyb found it 111°; and 113° under the
left ventricle of the heart in a soldier at Malta, three hours and a
half after death, in which case the blood was liquid, and yet coagulated,
as Dr. Davy informs me, on exposure to the air.

We want some exact observations on the temperature of fishes in hot
springs. Sonneret is reported to have seen fishes, apparently not in-
commoded, in a spring as hot as 187° Fahrn., in the island of Lugon,
one of the MantiUes ; and Cuvier received some fishes from the waters
of Cassa and Tozer, which are said to be as high as 170° Fahrn. c

a Exp. Inq. in Chem. Physiol. part i, c See Dr. Hodgkins's tr. of Edwards on

p. 114. Physical Agents, 8vo, Lond. 1832.

b Researches, i, 186-7, 230.

28 PROPERTIES OF

EXPERIMENT X.

I took a wide-mouthed phial, containing some serum, and
placing a thermometer in it, I put it into water which was
kept warm by a lamp underneath ; and, in making this experi-
ment with as much accuracy as I could, I found the heat re-
quired (xvn) was 160° ; which is about 40° more than is neces-
sary for the coagulation of the lymph.

(xvn.) The temperature required to coagulate the serum of different
animals is not the same. Dr. Davya observed a variation of 10° in the
coagulating point of the serum of mammals ; and it appears to vary with
the proportion of water in the serum, which may be indicated by its
specific gravity. Serum, too, first becomes opalescent and then viscid
at lower heats than are required to make it coagulate firmly, as I have
learned from experiments communicated to me by Dr. Davy, and from
others made by myself. He found that sheep's serum coagulated at
168° — 170°, and at 172° — 174° when 'diluted with one third of water;
that common salt, magnesia, carbonate of potash, and oxalic acid had
very little effect on the heat required to coagulate the serum ; that its
coagulation was prevented, even at 212°, by an excess of acetic, citric,
or tartaric acid ; that super-tartrate of potash promoted coagulation ; and
that it was retarded but not prevented by lime. Calf's serum he found
coagulated at 178°— 180°; pig's serum at 158°, at 180° when diluted
with an equal part of water, and with a sixth part of water was but
slightly thickened at 160°. The same serum after having been kept
six days, but quite fresh, had its colour less readily affected by heat.

Serum, sp. gr. 1031, gradually heated in a test-tube in water, from
the blood of a healthy horse, I found affected as follows : at 153° slightly
opalescent in reflected light ; at 155° distinctly so ; at 157° viscid ; at
158° a jelly, not breaking when inverted, semi-transparent in transmitted
light; at 164° a firm jelly, nearly opake in transmitted light; at 168°
quite opake and very firm. Kept for above two hours at 120° — 130,°
it became glairy and viscid, remaining quite transparent. Nitre had
little effect on the coagulation. But it was promoted by Glauber's salt ;
added in excess to the serum, this became white and opake at 144°, and
curdled throughout at 146°; an ounce of serum, with seventy grains of the
salt, kept fifteen minutes at 144°, became athin semi-transparent pulp, and
for fifteen minutes more at 146°, a feeble and quite opake jelly. Serum,
sp. gr. 1033, from a man aged 40, blooded for pneumonia : at Io6°
rather opalescent in reflected light ; at 158° liquidity impaired, and after
forty minutes a tender jelly ; at 159° coagulated firmly after twenty-six
minutes, opalescent in reflected light, and quite transparent in trans-
mitted light; at 169°, just the same : at 212° quite opake. The blood
was not buffy. Pellucid serum from a hydrocele, sp. gr. 1024, be-
came opalescent at 150°; coagulated at 160°; quite opake at 168°.

a Researches, Physiol. and Anat. ii, 95.

THE BLOOD. 29

As the blood is coagulable by heat, and as the heat of an
animal is increased in fevers, it has been supposed that the
blood might be coagulated by the animal heat, even whilst it
is circulating in the vessels ; but there is little foundation for
such an opinion ; since the animal heat is naturally only 98°
or 100°, and in the most ardent fever is not raised above 112°.
(xvn*).

Serum, sp. gr. 1029, frombuffy blood, tried at the same time for com-
parison, coagulated at 160° ; was semi-transparent at 1/0°, but forming
a much firmer clot than the serum of the hydrocele at a higher tem-
perature. The serum from the blood was quite opake at 212.°
(xvn*) See Note xvi.

CHAPTER II.

OP THE INFLAMMATORY CRUST, OR SIZE.

I SHALL next proceed to inquire into the formation of the
inflammatory crust, or size, as it is called.

This remarkable appearance is frequently met with in inflam-
matory disorders, and is formed by the coagulable lymph's
being fixed, or coagulated, after the red particles have subsided.
It has indeed been supposed to be formed from the serum of
the blood; and an excellent writer on this subject seems in
doubt to which of the two it should be attributed (xvin). But
that it is formed by the coagulable lymph alone, after the red
particles have subsided, appears from the following experiments.

(xvin.) Schwenkea thought that the huffy coat might be intermediate
to the serum and cruor. Gaubius, referred to in the Introduction, says
that the serum may be spontaneously converted into fibre, so as to form
the buffy coat ; Van Swieten5 asks whether that part may not be formed
from the serum ; Gaberc concludes that the pleuritic crust is the same
as the coagulable part of the serum ; and Huxhamd supposed that the
febrile heat turns the serum into the buffy coat. Haller6 describes the
serum as being spontaneously coagulable, forming the buffy coat of the
blood, polypi of the heart, and false membranes. A notice is given in
the Introduction of the opinion entertained by many eminent men that
the fibrin is not distinct from the serum ; of others that coagulation is
owing to an aggregation of the red corpuscles ; and further, that these
corpuscles are transformed into fibrin (see Notes I and CXVITI).

The fact probably is, as Liebigf states, that fibrin and albumen are
isomerical substances, that is to say, they may, under certain influences,
be suddenly converted into each other, as is the case with starch and
sugar, their elements being the same and in the same proportions.
The sudden changes in the properties of the blood during its evacuation

a Haematologia, pp. 157-8, 8vo, Hagae, d Essay on Fevers, pp. 5, 36, 6th ed. 8vo,
Com. 1743. Lond. 1769.

b Comment. Boerhaave, Aph. § 384. e Elem. Physiol. t. ii, pp. 125-6 ; Prim.

c De Humor. Animal. Melanges de Phil. Lin. Physiol. § 138, 8vo, Gott. 1780.

et de Math, de la Soc. Roy. de Turin, f Familiar Letters on Chemistry, p. 80,
t. iii, p. 67. 12mo, Lond. 1843.

PROPERTIES OF THE BLOOD. 31

EXPERIMENT XI.

In the month of June, when the thermometer in the shade
stood at 67°, I bled a man who had laboured under a phthisis
pulmonalis for some months, and at that time complained of a
pain in his side. The blood, though it came out in a small
stream, yet flowed with such velocity, that it soon filled the
basin. After tying up his arm I attended to the blood, and
observed that the surface became transparent, and that the
transparency gradually went deeper and deeper, the blood being

are favorable to this view ; but Miilderg asserts that there is a difference
between albumen and fibrin of one equivalent of sulphur in every ten
equivalents of protein. Denish supposes liquid albumen to be a salino-
alkaline solution of fibrin, a portion of which, precipitated during co-
agulation, he thinks is the fibrin of the blood. But it is well known1
that serum is not rendered turbid by many acids. Denis says that
1000 parts of water, charged with 100th part of nitre, and 1000th of
soda, dissolves about /OOths of fibrin, producing a fluid with all the
properties of serum. M. WurtzJ gives an account of a mode of pre-
paring albumen which is soluble without the aid of an alkali or salt.

Dr. Buchanan,k like the older observers, regards fibrin as a mere
modification of serum ; and the results of his experiments, in which a
mixture of serum from blood and serum from a serous cavity was found
to coagulate spontaneously, appear to me fully to warrant his conclu-
sion, which is not inconsistent with Liebig's, and to afford a simple ex-
planation of the formation of some of the most important healthy and
morbid products. In mixtures of serum of blood with serum either
from the pericardium, pleura, or vaginal tunic of the testicle, I have
seen the coagulum Assume various forms, not distinguishable from more
permanent structures. Sometimes it would be apparently a homogeneous
transparent jelly, either contracting but slightly or not at all, or so
greatly as to. form less than a third of the bulk of the serum ; often
presenting the character of a closed membrane of the utmost delicacy,
with processes running towards the centre, and forming cells for the
contained fluid : and occasionally a portion of the clot would be white and
nearly opake, somewhat resembling the cicatricula of a fowl's egg. The
ultimate structure of the membranous part was composed of most delicate
fibrils, as stated in Note vui ; and faint round molecules of extreme
minuteness were interspersed here and there. I may add that in several
trials the fluids were filtered both before and after mixing ; and that it
was clearly ascertained that neither of them would coagulate spontane-

s Chemistry of Vegetable and Animal * J. Davy's Researches, ii, 93 et seq.

Physiology, 8vo, part ii, p. 314. J Mr. Paget's Report, Br. and For. Med.

h Essai sur I'Application de la Chimie a Rev. vol. 21, p. 541.

1'Etude physiol. du Sang de THomme, k London Medical Gazette, xviii, pp.

p. 81, 8vo," Paris, 1838. 50 et seq.

32 PROPERTIES OF

still fluid. I likewise observed that the coagulation first began
on the surface, where it was in contact with the air, and formed
a thin pellicle ; this I removed, and saw that it* was soon suc-
ceeded by a second. I then took up a part of the clear liquor
with a wet teaspoon, and put it into a phial with an equal
quantity of water ; a second portion I kept in the teaspoon ;
and I found afterwards that they both jellied or coagulated, as
did also the surface of the crassamentum, making a thick crust.
On pressing with my finger that portion which was in the tea-
spoon, I found it contained a little serum.

From this experiment it is evident, that the substance which
formed the size was fluid after it was taken from the vein, and
coagulated when exposed to the air ; and as this is a property
of the coagulable lymph alone, and not of the serum, there
can be no doubt that the size was formed of the lymph (xix).

The following experiment, made on the blood, without expos-
ing it to the air, likewise proves the same fact.

EXPERIMENT XII.

Immediately after killing a dog, I tied up his jugular veins
near the sternum, and hung his head over the edge of the
table, so that the parts of the veins where the ligatures were
might be higher than his head. I looked at the veins from
time to time, and observed that they became transparent at
their upper part, the red particles subsiding. I then made a
ligature upon one vein, so as to divide the transparent from
the red portion of the blood ; and opening the vein, I let out
the transparent portion, which was still fluid, but coagulated
soon after. On pressing this coagulum, I found it contain a

ously alone, nor after dilution merely with distilled water. The blood-
corpuscles, as mentioned in Note cxviu, cannot be the immediate agents
in the formation of fibrin in these mixtures of serum. Dr. Buchanan1
has since found that the liquid of hydrocele will coagulate when there
is added to it either some washed blood-clot, shreds of the fresh bufty
coat, the same dried and powdered, the transparent clot from a blister,
or muscular fibre and other tissues. He and Dr. Anderson are now
satisfied that the fibrin exists in the animal fluids in a state of solution,
(xix.) I know not that this simple and convincing experiment was ever
before made. The claiming of it by Professor Owen for Mr. Hunter
has been noticed in the Introduction.

1 Lond. Med. Gaz. 1845, vol. i, pp. 617 et seq.

THE BLOOD. 33

little serum. The other vein I did not open till after the blood
was congealed, and then I found the upper part of the coagulum
whitish like the crust in pleuritic blood.1

And that the size is merely the coagulable lymph separated
by the subsidence of the red particles, will appear evident to
any person who will, as Sydenham (xx) directs, move a finger
or a teaspoon through the blood when he observes its surface
becoming transparent ; for in this case the blood that other-
wise would have been sizy, will now have a natural appearance,
or be without size; from the red particles being .prevented
from subsiding.

It has been a very generally received opinion, that inflam-
mation thickens the blood, and makes it more ready to coagu-
late. Nay, some have gone so far as to say, that in those dis-
orders where the inflammatory crust is seen, the blood is almost
coagulated even before it is let out of the vein. Now I am
persuaded from experiment, that the contrary of this is true ;
or that inflammation, instead of increasing the disposition of
the blood to coagulate, really lessens it (xxi) ; and instead of

1 This is not the only apparently healthful animal whose blood had a crust ; I have
seen it in others : whence I at first suspected that merely keeping the blood fluid for
a little time was sufficient to produce this appearance ; but I altered my opinion on
seeing that in the greatest number of animals it did not occur ; nor is it commonly
met with in the hearts of those persons who die a violent death, though the blood
remains longer fluid in such cases, than it does in the basin where the size appears.

(xx.) Sydenham, Opera Omnia, ed. Soc. Sydenhamianse, 8vo, Lond.
1844, sect 6, cap. iii, p. 248. In this case the proportion of fibrin
would be the same, as the red corpuscles are only prevented from sinking
by stirring them with the liquor sanguinis till it becomes viscid. And
even then, according to M. Denis, a the separation of the corpuscles and
fibrin is not entirely prevented ; for he states that the buffy part is diffused
throughout the clot in the form of whitish granulations ; and such, too,
he says, is the case when the buffy coat is prevented from forming, as
he maintains, in blood taken away during syncope. After stirring up
horse's blood, just when the buffy 'coat began to form, and preventing
its formation, I did not find any buffy granules on the cut surfaces of
the clot.

(xxi.) It has been generally supposed that the coagulation of the
blood in inflammation is so retarded as to cause or favour the sinking
of the corpuscles, and the consequent formation of the buffy coat. Mr.

3 Essai sur le Sang, p. 287, 8vo, Paris, 1838.

34 PROPERTIES OF

thickening the blood, really thins it ; at least that part which
forms the crust, viz. the coagulable lymph.

Hunter, a Dr. George Fordyce,b and Dr. B. G. Babington,c adopted this
view. Yet some recent observations are anticipated in the following
passage from Mr. Hunter's Surgical Lectures, vol. i, referred to below ;H
speaking of the blood in inflammation, he says, " The blood has an in-
creased disposition to separate into its component parts, the red globules
become less uniformly diffused, and their attraction to one another be-
comes stronger, so that the blood when out of the vessels soon becomes
cloudy or muddy, and dusky in its colour, and when spread over any
surface, it appears mottled, the red blood attracting itself and forming
spots of red." See Note xxm.

I have repeatedly seen a clear layer of liquor sanguinis, about one
eighth of an inch deep, appear on the surface of the blood of the horse
in two minutes, after which the sinking of the red corpuscles went on
with increased speed. In short, as mentioned in Note in, i, k, I believe
that the slow coagulation often occurring in blood drawn during in-
flammation, so far from being the cause, is an effect of the separation
of the fibrin and corpuscles. In two trials, I found that the" liquor
sanguinis remained longer fluid when separated, from the corpuscles
than when mixed with them.

Mr. Hewsond knew that the buffy coat does not necessarily follow from
slow coagulation ; and Dr. Davye observed that in certain cases in which
the inflammatory diathesis is best marked, the separation of the red
particles from the blood drawn is most rapid, often occurring in one or
two minutes ; and that in some diseases, particularly erysipelas, the
blood taken from a vein coagulates as rapidly as healthy blood, and yet
exhibits the buffy coat. The observations of Schroeder Van der Kolk and
Dr. Alison/ of Professor Hermann Nasse,g and of Mr. Wharton Jones,h
are to the same effect generally. Dr. Stoker1 has shown that blood
which coagulates in one, three, and five minutes, may have a buffy coat ;
and yet that it may be absent from blood that is ten, twenty, or even
forty minutes in coagulating. Results of the same kind from my ex-
periments are mentioned in the ' Edin. Med. and Surg. Journal,' v. 64,
p. 370.

Mr. Hewson, it will be observed, always states that in inflammation
the coagulable lymph is thinned or attenuated ; never that it is specifi-
cally lighter; yet he is often erroneously represented to have main-
tained the latter view. The consistency of the liquor sanguinis, and
the state of the red corpuscles leading to the formation of the buffy
coat, will be discussed in Notes xxiu and xxix.

a Works, ed. by Palmer,!, pp. 234-5, 381; f Out. Physiol. and Path. p. 47, 8vo,

iii, 356. ' Edin. 1833.

b Elements of the Practice of Physic, e Henle, Anat. Gener. tr. par Jourdan ,

2d ed. 8vo, Lond. 1 768, part ii, p. 30. i, 468.

«-' Cyclopedia of Anatomy, i, 419. h Edin. Med, and Surg. Journ. Ix, 309.

d See his Exp. x vi, and xxvii. * Pathological Observations, 8vo, Dublin.
«• Phil. Trans. 1822, p. 271 ; Researches 1823, pp. 37, 44.

ii, 48.

THE BLOOD. 35

In the first place, that inflammation really lessens the dis-
position to coagulate, will appear evident to every one who at-
tends to the jellying of such blood as has a crust. For in all
those cases the blood will be found to be longer in congealing,
than in its natural state. To this opinion I was first led by
attending to the phthisical patient's blood above mentioned;
but I have since made a comparison, which seems to prove the
fact. For, from a variety of experiments made on the blood of
persons nearly in health, or at least who had no inflammatory dis-
order, and no crust on their blood, I found that after being
taken from a vein, it began to jelly in about three minutes and
a half. The first appearance of coagulation was a thin film on
the surface near the air-bubbles, or near the edge of the basin ;
this film spread over the surface, and thickened gradually till
the whole was jellied, which was in about seven minutes after the
opening of the vein ; and in about ten or eleven the whole was
so firm, that, on cutting the cake, the gashes were immediately
filled up by the serum, which now began to separate from the
crassamentum. But in those persons whose blood had an in-
flammatory crust, the coagulation was much later; as will ap-
pear from the following experiments.

EXPERIMENT XIII.

I bled a woman who was seven months gone with child, and
the blood was received into a basin. In five minutes after the
vein was opened, a film first appeared ; but this spread so slowly,
that in ten minutes it did not cover the whole surface ; in fif-
teen minutes it had nearly spread over the surface ; but the
rest of the blood was quite fluid, at least for some depth, and
even in half an hour it was not so firmly jellied as it was after-
wards. In this case there was a very thick and strong crust
or size.

EXPERIMENT XIV.

Having bled a person with a violent rheumatic pain in his
breast, the blood was received into three teacups, and each of
them had afterwards a crust. In the first I observed the pro-
gress of the coagulation as follows : The beginning of the co-
agulation was not marked, but at the end of half an hour the
film was not thicker than common writing-paper ; and this

30 PROPERTIES OF

being removed, a little of the clear lymph was taken up with
a wet teaspoon, put into a clean cup, and was twenty minutes
more in coagulating. Even at the end of an hour and a half,
the whole of the blood was not jellied ; for at this time I re-
moved the film or pellicle, and took up a second portion of clear
lymph with a spoon, and put it into a teacup, where it jellied
afterwards ; though this jelly was not indeed quite so firm as
the crassamentum itself.

EXPERIMENT XV.

A woman, with a slight inflammation in her throat, had
eight ounces of blood taken from her arm ; the blood was re-
ceived into a basin, and the bleeding finished in four minutes
and three quarters, when a film began to form near the air-
bubbles ; in seven minutes a transparent size appeared over a
considerable part of the surface which was quite fluid, whilst
the rest of the blood was coagulating, there being now a very
distinct red crust over the rest of the surface.

Now, from comparing these experiments with what has been
observed of the coagulation of the blood, where there is no in-
flammatory crust or size, is it not evident that the blood remains
longer fluid after being exposed to the air, and has less dispo-
sition to coagulate, in those cases where there is a size, than
where there is none ? for where there was none, it was found
to coagulate completely in seven minutes ; but in one of the
others, where the size was very thick, it did not completely co-
agulate in less than an hour and a half.

The power that inflammation has in lessening the disposition
of the lymph to coagulate is likewise plain from the following
experiment, where the blood in the heart of a dead animal
seems to have congealed very slowly.

EXPERIMENT XVI.

A dog was killed eight hours after receiving a large wound
in his neck. The wound had during this time inflamed con-
siderably. Upon opening him next morning, when he had
been dead thirteen hours, a large whitish polypus was found in
the right ventricle of his heart ; under this was a little blood
still fluid, which being taken up with a teaspoon, coagulated
soon after being exposed to the air.

THE BLOOD. 37

It may be proper to observe here, that in the hearts of animals
which had died without any inflammation, I have found the
blood entirely coagulated long before this time. And that
from opening them at different times, I have seen it coagulate
in their hearts after death, in the same gradual manner that it
does in their veins, when its motion is stopped by ligatures ; as
related in page 22.

In the next place, that the blood is really attenuated (see Notes
xxi, xxui, and xxix) in inflammatory disorders, where the whitish
crust or size appears, is probable from the following circumstances :
1st. It even seems thinner to the eye. 2d. The red particles or
globules subside sooner in such blood than in that of an animal in
health. This seems proved by observing that in the above-
mentioned experiments, where the blood was at rest in the
veins, it was not covered with a crust, except in one or two in-
stances, though in all those cases it remained longer fluid than
the blood commonly does in a basin, after bleeding, where the
crust appears. And again, the blood in the heart of an animal
that dies aviolent death, is not generally covered with a white crust,
notwithstanding it is so late in being congealed (see Note xin).
These circumstances show, that something more than merely a
lessened disposition tocoagulate is necessary for the fonningof the
crust or size. 3d. The globules more readily subside in inflamma-
tory cases, from the surface of the whole mass of blood, than they
will afterwards do from the surface of a mixture with the serum
alone, of which the following experiments are a proof. But, before
I relate them, let me observe, that they were made with a view
to discover whether the inflammatory crust could be owing to
any other cause than to the attenuation of the coagulable lymph,
and to its disposition to coagulation being lessened : and as the
same appearance might be suspected to arise from an increased
specific gravity in the red particles, or from the serum alone
being attenuated, I endeavoured to decide the question in the
following manner :

EXPERIMENT XVII.

Into a phial, marked A, I put an ounce of the serum of the
blood of a person whose crassamentum had an inflammatory
crust.

Into another, marked B, I poured an ounce of the serum of
a person whose blood had no crust ; then to each of these, I

38 PROPERTIES OF

added a teaspoonful of serum, loaded with the red particles of
a person whose blood had no inflammatory crust or size. In
attending to them, I could not observe that the red particles
subsided at all sooner in the serum of the blood that had a
crust, than they did in the serum of that blood which had no
crust. Thence, I conclude, that the serum (xxn) is not atte-
nuated in those cases where the inflammatory crust appears.

(xxu.) Mr. Huntera concluded that the red corpuscles of the blood
during inflammation are increased in specific gravity, and the serum
diminished in specific gravity. Mr. Wharton Jonesb found that the
corpuscles of buffy blood subside more rapidly in its serum than the
corpuscles of blood not buffy do in its serum. But both the consistency
and specific gravity of a fluid may be incorrectly indicated by the pace
with which these corpuscles fall through it, as explained in Note xxm.

The serum of the blood in inflammation is very variable in density.
Mr. Thackrah,c finding, in some trials, that a marked increase in the
proportion of fibrin was attended by a decrease in the solid matter of
the serum, supposed, like the older observers referred to in the Intro-
duction and in Note xviu, the fibrin of bufly blood to be formed at the
expense of the albumen. Dr. B. G. Babirigtond was at one time led
to believe that the serum of bufly blood is always deficient in its due
proportion of albumen ; but he has since found this not to be the case,
having met with blood thickly buffed, of which, in one specimen, the
specific gravity of the serum was 1024, and in another 1040. Dr. Trail!6
found about double the usual proportion of albumen in three specimens
of milky serum taken from patients labouring under inflammatory dis-
eases. Gendrinf states that the serum of blood in inflammation is made
more viscid by an excess of albumen, and that the serum expressed from
the bufly coat contains a greater proportion of albumen than the rest
of the serum. Andralg says he agrees with Traill and Gendrin that the
proportion of albumen is nearly doubled in the serum of buffy blood.
Thackrah11 also inferred that the serum separating first from the clot,
contains less solid matter than the serum which separates last.

In some observations, I found, like Dr. Davy,1 but little* connexion
between the density of the serum and the presence of the bufly coat.
Thus, in a man aged 33, affected with pulmonary catarrh, the blood
thickly buffed, the specific gravity of the serum was 1024; in a man
aged 25, blooded for iritis following venereal disease and the use of mer-
cury, the blood slightly buffed, the serum was 1029 ; in a man aged 19,
labouring under common continued fever, the blood thickly buffed, the
serum was 1034; in a man aged 30, with jaundice, the blood thickly
buffed, the serum was 1035 ; in a boy aged 4, the blood moderately
buffed, the serum was 1025. Serum from very thickly buffed blood of
a healthy mare was found to be 1031, and from similar blood of a

a Works, edited by Palmer, iii, 356. f Hist. Anat. des Inflammations, torn. ii>
b Br. and For. Med. Rev. xiv, 590. pp. 442-3, 8vo, Paris, 1826.

c On the Blood, p. 212, ed. 1834. « Anat. Path. t. i, p. 534, 8vo, Paris, 1829.

<> Cyclopaedia of Anatomy, i, 419. h On the Blood, ed. 1834, pp. 41, 232.

e Annals of Philos. 1823, vol. v, 199. ' Researches, ii, 34-37.

THE BLOOD. 30

Lastly, to see whether the specific gravity of the red globules
was increased, I proceeded as follows :

EXPERIMENT XVIII.

I poured into a phial C, a portion of the serum of the blood
which had no crust ; and likewise into another D, a second
portion of the same serum. I then added to C a teaspoonful
of the same serum, loaded with red particles from the blood
which had an inflammatory crust. And into D, I poured a tea-
spoonful of the same serum, loaded with the globules of that
blood which had no crust. In viewing these, I could not ob-
serve that the globules of the blood which had an inflammatory
crust subsided sooner than those of the blood which had none :
whence I inferred, that the specific gravity of the red particles,
or globules as they are called, is not increased in those cases
where the crust appears. And, therefore, since that inflam-
matory crust or size seems neither owing to the serum's being
attenuated, nor to an increased specific gravity in the red par-
ticles, it probably depends solely upon a change in the eoagu-
lable lymph. And what seems farther to confirm this inference,
in none of these experiments did the red particles subside from
the surface of the serum in twenty minutes, though, where the
crust appears, they subside from the surface of the blood in
half that time ; so that the whole mass of blood seems to be
thinner than the serum alone ; or, the coagulable lymph seems
to be so much attenuated in these cases, as even to dilute the
serum, which at first sight appears a paradox.

May we not, therefore, conclude, that in those cases where
the inflammatory crust appears, the coagulable lymph is thinner,

healthy gelding 1035. In both trials with the blood of the horse, the
serum first exuding from the clot, the serum last exuding from the clot,
and the serum obtained from the buffy coat, by pressure through a linen
bag, were all ascertained to be of the same specific gravity, con-
trary to what might have been expected from the observations of
Thackrah and Gendrin. The serum was in every instance filtered be-
fore it was weighed, and its specific gravity noted at a temperature of
60°. Mr HunterJ found that the serum of blood from a person with an
inflammatory complaint, and serum of blood in a case not inflammatory,
were nearly the same respecting coagulation and the quantity of serosity,
or matter not coagulable by heat. The coagulating point of serum varies
with its proportion of albumen. See Notes in, g, xvn, and LII.

' Works, edited by Palmer, iii, 51.

40 PROPERTIES OF

and its disposition to coagulation is lessened? both of which
circumstances contribute to the subsiding of the red globules
from the surface of the blood, which then coagulating gives
rise to this appearance, called the inflammatory crust or size,
in the blood of pleuritic or rheumatic patients.1

How contrary to the conclusion, which these* experiments
lead us to, are the opinions of some medical writers on this
subject ! How frequently do we find it said, that the blood is
thicker in inflammatory disorders, where that size occurs ; and
that a large orifice is necessary to let out the vitiated blood !
That 'a large orifice is preferable to a small one in many cases,
where such blood is found, I believe to be true ; but that its
advantages are owing to its letting out the thickened blood,
seems improbable from what we have seen in the experiments
above related : they are perhaps nearer the truth, who attribute
it to the suddenness of the evacuation.

It may be proper to observe here, that this size or whitish
crust is not a certain sign of inflammation (xxin) ; it being
1 This remarkable appearance might indeed be accounted for, by supposing that
the lymph had ascended to the surface of the blood in those cases ; but this is im-
probable, from considering that, in its coagulated state, it is of greater specific gravity
than the serum, and sinks in it.

(xxiii.) That inflammation is not certainly indicated by the buffy
coat is shown by the fact that this part forms regularly on the blood of
the horse, as was probably known to Harvey. a It seems to have been
scarcely known to Dr. Simon,b though noticed by Dr. Allan Thomson,0
and more particularly by Andral,d Gavarret, and Delafond; the last three
writers ascribe it, and the formation of the buffy coat generally, to an
excess of fibrin in relation to the other parts of the blood, as likewise did
some of the older observers referred to in Note I. The buffy state of the
blood from women far advanced in pregnancy is well known ; and Mr.
Heye observed the great abundance of fibrin in such blood.

Mr. Hewson inferred that the buffy coat is owing to an attenuation
of the liquor sanguinis, because he found in his ingenious and I believe
original experiments, that the red corpuscles sink more quickly in it
than in the serum alone. The fact is undoubted ; but the inference is
probably incorrect. The rapid sinking of the corpuscles during the
formation of the buffy coat arises simply from their clustering in such
blood, and not from any thinning of the liquor sanguinis nor from retarded
coagulation (see Notes xxi and xxix). The collection of the corpuscles
into piles in blood not buffy is well known (see Notes c and cix) ; in

a De Generatione Animalium, 4to, Lond. c Syllabus of Lectures on Physiology,
1651, p. 160. p. 13, 8vo, Edin. 1835.

b Animal Chemistry, i, pp. 115,292,340, d Hematol. Pathol. pp. 28 et seq. 8vo,
tr. by Dr. Day, for the Sydenham Paris, 1843.

Society, 8vo, Lond. 1845. e On the Blood, p. 66, 8vo, Lond. 1779.

THE BLOOD. 41

often met with where there seems to be no such disease, in
particular in the blood of pregnant women. And that it differs
much in density in different cases ; in some it is extremely
firm, in others it is spongy or cellular, and contains much serum
in its* cells. These diversities we shall endeavour to explain
hereafter, when we have laid before the reader some more ob-
servations on the coagulation of the lymph.1

1 Although this essay has been so lately printed, yet most of the facts which occur
in the preceding pages have been mentioned in my « Anatomical Lectures/ ever since
the year 1767 ; and some of them were mentioned publicly even before that time.
This I thought necessary to observe, because many of them have since appeared in
other publications.

buffy blood they are still more closely connected, almost as if fused to-
gether, and the piles run into little clumps often visible to the naked eye.
Now we know that coarse particles sink more rapidly in a liquid than
fine ones, and the clumps of corpuscles in buffy blood represent much
coarser particles than their composing single piles or separate corpuscles.
The more they run together, therefore, the faster they will fall in the
liquor sanguinis, so as to produce the buffy coat.

Accordingly, it was found in my experiments that, during the for-
mation of the buffy coat, the corpuscles will at first take about two and
a half minutes to sink an eighth of an inch in the liquor sanguinis, and
fall five or six times faster in the next two or three minutes ; and that
this remarkable acceleration in rhe sinking of the corpuscles is connected
with their increasing aggregation, appeared from the fact that their rapi-
dity of sinking was increased by increasing their aggregation, though the
means used did not attenuate the blood ; and prevented or even reversed
by destroying the aggregation, though by means which made the blood
much thinner and lighter. There is also an acceleration, after a few
minutes, in the pace with which the corpuscles of buffy blood sink in
the serum, though to a less degree than in the liquor sanguinis. These
observations- support the views concerning the formation of the buffy
coat originally given by Professor Herrman Nasse of Marbourg, adopted
by Professor Henle, Drs. Carpenter and C. J. B. Williams, and arrived
at, I believe independently, by Mr. Wharton Jones.

The efficacy of saline medicines in inflammation probably depends
on their correcting the disordered state of the blood, by preventing or
destroying the aggregation of the corpuscles, and consequently their
tendency to separate from the fibrin and to accumulate in the minute
vessels ; and hence the application of a solution of salt to inflamed parts
might prove a very useful and simple remedy.

The experiments from which the results mentioned in this Note were
obtained, are detailed in my paper on Buffy Blood, 'Edin. Med. and Surg.
Journ./ v. 64, pp. 360-375, in which I have given some historical
notices, and references to various writers, concerning the consistency
of the liquor sanguinis andthe state of the red corpuscles in inflammation.

CHAPTER III.

DIFFERENT TIMES IN BLOODLETTING ; OF THE STOPPING OF
HEMORRHAGES; AND OF THE EFFECTS OF COLD UPON THE
BLOOD.

*

IT has been observed by those who have written on the
blood, that it sometimes happens in bloodletting, that the first
cup has an inflammatory crust, whilst the last has none ; but no
satisfactory reason has been given for this difference. One
might suppose that it was owing to some circumstance in the
bleeding, such as in the different velocity with which the blood
flowed into each cup, or to the last cup's being agitated so as
to prevent the separation of the lymph : but I have seen it
where there was no difference of this sort, nor in any other cir-
cumstance that I could observe. I therefore suspect that in
such cases the properties of the blood are changed, even during
the time of the evacuation ; to which opinion I was led by the
following experiments.

EXPERIMENT XIX.

Nine ounces of blood were taken from a woman who had
been delivered two days before, and who at that time laboured
under a fever, with a considerable pain in her side and in her
abdomen. The blood was received into a basin, and her arm
was tied up ; when, on looking at the blood, I found its surface
v transparent for some depth, an indication of a future crust ;
and as her pain was not abated, and as her pulse could bear
it well, I removed the ligature from her arm, and took away
about six ounces more, into three teacups; but what appeared
to me remarkable, although the blood flowed as fast into each
of the cups as into the basin, and when full they were imme-
diately set down on the same window, yet there was no iiiflam-

PROPERTIES OF THE BLOOD. 43

matory crust on the blood in the cups, though a very dense one
on that in the basin. And again, although the blood in the
basin had been taken away some minutes before that in the
cups, yet it was later in being completely coagulated ; as was
evident on comparing them.

I had an opportunity of repeating the experiment in the
evening; for the symptoms of inflammation seeming equally
violent, it was thought proper by the physicians who attended
her to take away more blood ; which was done by opening the
same orifice, when three teacups were nearly filled, and set in
the same place ; and it was observed, that the first had a crust,
though not so thick a one as in the first bleeding; but the
other two cups were without this appearance, though the blood
had flowed into them even more quickly than into the first.1

EXPERIMENT XX.

A gentleman, who laboured under an inflammatory com-
plaint, had about nine ounces of blood taken from his arm.
This quantity was divided into four portions ; the first was re-
ceived into a cup, and was in measure little more than an
ounce ; the second into a basin, to the quantity of two ounces ;
the third into a cup, which held one ounce ; and the fourth
into a basin, to the quantity of three ounces. Each vessel
was immediately placed upon the window ; and it was observed
that the blood in the first was latest in coagulating, and had a
crust over the whole surface ; that in the second had a crust
only upon a part of its surface; but that in the third and
fourth had none, and manifestly coagulated before either of the
other two.

Now, since in these experiments the blood in the first cups

1 As this experiment seems contradictory to some mentioned hereafter, in the last
cups being filled rather sooner and yet coagulating sooner, which might be suspected
to be owing to the vessel's acting more strongly at the latter part of the operation
than at the beginning ; it is therefore necessary to observe, that the difference in this
experiment appeared to be only owing to a difference in the size of the orifice, for
when the ligature was first removed, the old wound was not so much torn open as it
was afterwards, when it was more enlarged in order to hasten the evacuation. But
it did not, in the beginning of the operation, trickle down the arm as in Exp. xxvn,
where the size of the orifice was not enlarged from the first, and yet in proportion as
the operation advanced, the velocity of the blood increased ; which was thence con-
cluded to be owing to ail increased action of the blood-vessels.

44 PROPERTIES OF

was later in coagulating than that in the last, and since the
blood in the first cups alone had a size, is it not probable, that
even during the short time taken up in the evacuation, the pro-
perties of the lymph had been changed, and that it was owing
to this change (xxiv) that the size disappeared ? It might in-
deed, at first sight, seem possible that the bleeding had only
let out the vitiated part ; but this is not at all likely ; for, sup-
pose a part only of the blood was vitiated, that part must have
been equally diffused through the whole mass, and there is no
probability of its getting out of the vessels before the rest of
the blood; and consequently it ought to have appeared in the
last equally as in the first cup, but it did not. Bleeding, there-
fore, in those cases alters the nature of the blood, not by re-
moving the vitiated part, and giving room for new blood to be
formed, as has been supposed ; but probably by changing that
state of the blood-vessels, on which the thinness, and lessened

(xxiv.) The change probably consists in a dilution of the blood, as
it may be supposed that the contents of the lymphatic vessels are rapidly
poured into the veins as the blood flows out. The evidence originally
given by Dr. Davy in his Thesis,a that the blood which flows last and
coagulates first contains most water, is mentioned in Note i. I did not
observe, in some experiments, that adding distilled water to the blood
hastened its coagulation, though it was hastened by the addition of
serum, and still more by the addition of red corpuscles : See Exp. 45-63,
'Edin. Med. and Surg. Journ.' vol. 64, p. 373. Mr. Prater,b Schrceder
Van der Kolk, and Dr. Alison,0 had before observed the same effect
from diluting the blood with serum, and applied it to account for the
more rapid coagulation of the last flowing blood.

On the curious subject of the change in the properties of the blood
during its evacuation, there are the three following hypotheses : 1 . That
of Quesnayd and Hewson, in which vascular action is supposed to be
the chief cause. 2. That of Dr. Davy,e in which the change is con-
jectured to be owing to blood from different parts of the body entering
the stream flowing in any bloodletting. 3. That of Liebig, described
in Note xvin, that albumen and fibrin are isomerical substances. The
second hypothesis is not incompatible with the third. Mr. Thackrahf
has given an account of the difference in the blood from divers vessels.
But some of his results are so extraordinary as to require further ex-
amination ; the wide range, for instance, in the specific gravity of blood
and its serum from the portal vein.

a Tent. Exp. quaedam de Sang. comp. d Traite de la Saignee, p. 415, nouv. ed.

p. 37, 8vo, Edin. 1814. 8vo, Paris, 1750. He refers only to

b Exp. Inq. in Chem. Physiol.- p. 105, the excess of fibrin in the blood in

8vo, Lond. 1832. inflammation.

c Outlines of Physiology and Path., p. e Researches, ii, 67, 83.

46, 8vo, Edin. 1833. f On the Blood, ed. 1834, p. 94 et seq.

THE BLOOD. 45

tendency of the lymph to coagulation, depends ; which surely
is a very curious circumstance.1

From this observation we may be led to think, that it may
be useful to receive the blood more frequently into small cups,
instead of a basin, and to attend more carefully to the alter-
ation produced upon it by bleeding ; as we may by that means
perhaps learn to determine better what quantities should be
taken away in particular cases. For it would seem probable
that the operation is likely to have the most effect on the dis-
ease, in those cases where the greatest change is produced by
its means, on the disposition of the blood to coagulate ; and of
that change we can judge, by comparing the blood in the first
cup with that in the last; for the first cup will nearly show
the state of the blood at the beginning, and the last cup the
state of the blood at the latter part of the evacuation.

It frequently happens that, instead of an inflammatory crust
over the whole surface of the crassamentum, there is only a
partial one, which appears in large spots or streaks. In such
cases I have observed, that only a part of the blood had its
disposition to coagulate lessened, as in Experiment xv, in
which some of the blood remained fluid and transparent, where
those streaks appeared, for some time after the coagulation had
begun in other parts of the surface. Now whether in those
cases there had been the same difference before the vein was
opened, or whether the whole blood had not been of the inflam-
matory kind, before venesection, and a part of it was changed
as it ran out, or as soon as the general fulness was diminished,
may be a question ; but the probability, I think, is much in
favour of its being changed during the time of the evacuation,
from what was observed in the last experiments.

When I had observed that this disposition of the lymph to
coagulate was increased by bleeding, or by weakening the ac-
tion of the blood-vessels, I suspected that possibly in those
cases where the body was very weak, the disposition to coagu-
late might be so much increased, that instead of being three or

1 That the properties of the blood can be changed by emptying the blood-vessels,
is likewise proved by an experiment hereafter to be related, where the blood in an
animal in health was found to have its disposition to coagulation increased in pro-
portion as the vessels were emptied, and as the animal became weaker. It may like-
wise be proper to mention, that though the inference is here drawn from two experi-
ments only, yet I have likewise observed the same appearance in other cases, which
I have thought unnecessary to relate.

46 PROPERTIES OF

four minutes in beginning to do it, after it is let out of the
veins (as is the case in people in health) it might coagulate in
less time, or almost instantaneously; for I imagined, that un-
less this took place, we could hardly conceive how the blood
should ever have time to coagulate in ruptured vessels, so as tcf
stop hemorrhages, as it is believed to do. And upon this oc-
casion I recollected a remark that I had heard, particularly
from Dr. Hunter, which is, " That the faintness which comes
on after hemorrhages, instead of alarming the bystanders, and
making them support the patient by stimulating medicines, as
spirits of hartshorn and cordials, should be looked upon as
salutary; as it seems to be the method Nature takes to give
the blood time to coagulate." Now as this seemed to favour
my suspicion, I determined to make the experiment.

EXPERIMENT XXI.

Believing it would be sufficient for this purpose, to attend to
the properties of the blood, as it flows at different times from
an animal that is bleeding to death, I therefore went to the
markets, and attended the killing of sheep ; and having re-
ceived the blood into cups, I found my notion verified. For I
observed, that the blood which came from the vessels imme-
diately on withdrawing the knife was about two minutes in
beginning to coagulate ; and that the blood taken later, or as
the animal became weaker, coagulated in less and less time ;
till at last, when the animal became very weak, the blood,
though quite fluid as it came from the vessels, yet had hardly
been received into the cup before it congealed. I have also
repeated the experiment, by receiving blood into different cups
at different times, whilst the animal was bleeding to death;
and though the time taken up in killing the animal was not
commonly more than two minutes, yet I observed, on compar-
ing the cups, that the blood which issued last coagulated first1

1 It may be necessary to mention a circumstance that has occurred in repeating
these experiments ; which is, that although the last cup being taken from the animal
when much reduced, always coagulated in less time than the first, yet, when four or
five cups were used, the blood in them did not always coagulate precisely in the in-
verse order of their being filled ; for sometimes the second coagulated before the third.
This circumstance at first seemed contradictory to the general conclusion, but on a
more careful examination, it was suspected to be owing to the straggles (or temporary
exertion of strength of the vessels) of the animal, and no difference was observed in
the exposition to cold or to air.

THE BLOOD. 47

(xxv). I have observed likewise, that the blood coagulates
with a different appearance in proportion as the animal becomes
weaker; that which follows the knife begins to coagulate in
about two minutes ; it first forms a film or pellicle on the sur-
face, which extends gradually through the whole blood, yet
so slowly that its progress may be observed, especially if the
pellicle be moved from time to time. But the blood that
comes from the fainting animal is coagulated in an instant,
after it once begins. From this circumstance, that the dispo-
sition of the blood to coagulate is increased as the animal be-
comes weaker, we may draw an inference of some use with re-
gard to the stopping of hemorrhages, viz. not to rouse the pa-
tient by stimulating medicines, nor by motion, but to let that
languor or faintness continue, since it is so favorable for that
purpose; and also that the medicines likely to be of service in
those cases, are such as cool the body, lessen the force of the
circulation, and increase that languor or faintness.1 For, in
proportion as these effects are produced, the. divided arteries
become more capable of contracting, and the blood more readily
coagulates ; two circumstances that seem to concur in closing
the bleeding orifices.2

It has been questioned whether bloodletting can be properly

1 Besides giving stimulants and cordials to counteract the fainting, it is a common
practice in many parts of England to give women, who are flooding, considerable
quantities of port wine, on a supposition that it will do them service by its astringency.
But surely, from its increasing the force of the circulation, it must be prejudicial in
those cases. Perhaps man? of the remedies called styptics might be objected to for
the same reason.

2 It has of late been proved by experiments, particularly by those of the ingenious
Mr. Kirkland, that the larger arteries, when divided, contract so as to stop the he-
morrhage. But the large coagula which we see in the orifices of the vessels of the
uterus of those who die soon after delivery, and the stopping of hemorrhages where
the blood-vessels were ruptured on their sides and not entirely divided, make me
believe that contracting the bleeding orifice is not the only method nature takes to
stop an hemorrhage. Her resources indeed are great, and she has often more methods
than one of producing the same effect.

(xxv.) See Note xxiv. The contrary results obtained by Mr. Heya
are curious. Mr. Thackrah's experiments,5 afterwards witnessed by
Mr. Hey, agree with Hewson's, as Hey himself admitted.0

:1 On the Blood, 24 et seq. 8vo, Lon. 1779. ° Mr. Grainger's Elem. Gen. Anat. p. 41,
*> On the Blood, ed. 1834, p. 138. 8vo, Lond. 1829.

48 PROPERTIES OF

recommended in hemorrhages, excepting in those that are at-
tended with evident signs of plethora : but do not these experi-
ments show that a vein may be opened with propriety, even
where there is no plethora, in order suddenly to bring on weak-
ness ; by which the momentum of the blood may be so dimi-
nished, and the disposition of the lymph to coagulate may be so
increased, as to stop the hemorrhage ? For, when we consider
how soon the blood-vessels contract, and adapt themselves to the
quantity of blood which they contain, it seems not improbable
that in some cases where the hemorrhage is not profuse, but
long continued, the strength of the patient may be so recruited,
that the disposition to coagulate shall not be sufficiently in-
creased, or the extremities of the vessels sufficiently contracted,
for the stopping of the bleeding ; but, by emptying the vessels
suddenly, this effect may be obtained, and the hemorrhage may
be stopped by the loss of less blood than would have happened,
had only the slow draining been continued.

Although the whitish crust so commonly seen in inflam-
matory disorders, has so very morbid an aspect, as might in-
duce us to consider it as inflammatory, and to bleed repeatedly
in all those cases "where it occurs, yet I believe we should act
improperly : for, to say nothing of pregnancy, in which the
appearance is almost constant, there are few physicians that
have not seen patients, who, even in such circumstances, were
the worse for this evacuation. Nor need we be surprised that
this should happen, considering how soon in some instances
this size disappears ; and if so, may we nof suppose, that it may
likewise soon be formed, even by a short exertion of strength
in the vessels ? Perhaps this was the case in the gentleman
mentioned in page 43, who in less than twenty-four hours after
bleeding had symptoms of great weakness.

As it appears from these experiments, that the disposition of
the blood to coagulate is increased by bleeding, it may be useful
to attend more to this circumstance, and to compare the coagu-
lation of the blood in the last with that in the first cup, even in
cases that are not attended with the inflammatory crust. And it
may likewise be worth while to make the same comparison in
those cases where every cup has a crust ; which frequently hap-
pens both in rheumatic and in phthisical complaints. By these

THE BLOOD. 49

means we may judge what effect the evacuation has produced
on the strength or fulness of the vessels ; and may, perhaps, by
inspecting the last cup, especially if it contains only a small
quantity, be able to guess pretty nearly at the nature of the
blood which remains in the body. In the rheumatic case men-
tioned in page 35, every cup contained this crust : and although
the blood in the last cup coagulated in much less time than
that in the first, yet, as it was later in coagulating than common,
I suspected what remained in the vessels had the same dispo-
sition ; but the patient recovered without repeating the evacua-
tion.

It may be mentioned here, that I have once or twice seen
blood which, when it first began to coagulate, had on its sur-
face a red pellicle, and underneath a transparent fluid, which
afterwards formed a crust. In these cases, if the red pellicle
had not been removed before the rest of the blood had con-
gealed, we might have concluded that no part of the blood had
this disposition to form a white crust. This appearance, I
should imagine, was owing to the blood, where in contact with
the air, having coagulated before the red particles had time to
subside from that part of the lymph which had its disposition
to coagulation lessened.

The learned Professor de Haen has taken notice of a curious
appearance of the blood, which he could not account for ; but
which, I presume, may be explained from some of the above
experiments. His observation is, " that having bled a person
in a fever, the blood was covered with an inflammatory crust,
and upon examining the crassamentum in one of the cups, he
found that it formed a sort of sac containing a clear fluid :
this fluid being let out, and the cup set by, on examining it
next morning, he observed a very firm crust covering the whole
again, and extending to the bottom of the cup."1 I once met
with a case similar to this ; for, having bled a person into four
cups at ten o} clock in the morning, on looking at the blood
afterwards, at five in the afternoon, I found the serum had not
separated from the crassamentum in the first cup ; but the
crassamentum felt as if it contained a fluid in a bag, as Professor
de Haen has described it. Upon pressing it, the fluid gushed
out, and in a few minutes after being exposed to the air, coagu-

1 Vide Rat. Medendi, cap. vi.

4

50 PROPERTIES OF

lated : there was however this difference in the two cases, that
in mine the fluid was red, so that it formed a red crust over
the first, which was white. Now this seems to have been owing
to the blood's having first coagulated, where it was in contact
with the air and with the sides of the cup ; and the fluid which
gushed out was the serum, with a part of the coagulable lymph,
which still remained fluid; but, when exposed to the air, it
jellied or coagulated, as it naturally does. That one part of
the lymph can remain fluid after the other is coagulated, is
proved by some of the preceding experiments ; and I have more
than once seen blood which appeared perfectly jellied soon
after bleeding ; yet, on cutting into the coagulum, a transparent
fluid has oozed out, which afterwards jellied. And so slowly
does this coagulation proceed in some cases, that, in an experi-
ment mentioned before, a part of the blood in a dog's heart
was found uncoagulated thirteen hours after death. And
I have likewise distinctly observed, that in some cases
where the disposition to coagulate was much lessened during
the evacuation, the blood at the bottom of the cup has jellied,
whilst the greatest part of the size at the top was yet fluid;
there being only a thin pellicle on its surface, where it was in
contact with the air (xxvi) .

Another instance of a change in the properties of this coagu-
lable lymph, which appears curious, was seen in some experi-
ments, where I had occasion to throw the blood into water, and
into oil, during the winter season, whilst the heat of the water
and of the oil was no greater than 41° of Fahrenheit's scale.
In all those experiments, I found that the disposition to coagu-
late was lessened, the blood becoming more and more viscid,
but did not coagulate whilst in that degree of cold. I shall
next relate those experiments.

EXPERIMENT XXII.

The jugular vein being properly tied, and then cut out from
a rabbit just killed, was then thrown into water of 41° of heat,

(XXVT.) See Exp. xvi, and Notes xii, x, xm and in, i. k. I have
repeatedly removed a clot as soon as it was formed, and observed that
it was succeeded by another. Dr. Davya noticed the same fact.

a Researches, Physiol. and Anat. ii, 68.

THE BLOOD. 51

and taken out at the end of half an hour ; when the blood was
found to be still fluid, though rather more viscid than natural ;
but, after being exposed to the air, it coagulated.

EXPERIMENT XXIII.

Two pieces of the jugular vein of a dog, just killed, were put
into water, in which the thermometer stood at 41°; one was
taken out after twenty minutes, and the other after three quar-
ters of an hour ; the blood in both was found to be fluid, and
to coagulate afterwards.

As it was evident from these experiments, that the water had
lessened the disposition of the blood to coagulate, I next in-
quired to what property in the water this effect could be owing ;
and to see whether water that was warmer would not have the
same effect, I made the following experiment.

EXPERIMENT XXIV.

On December the 13th, I cut out two pieces of the jugu-
lar vein of another dog, immediately after his death. One
piece was put into cold water, and the other into water kept
warm by a lamp, so that the heat never varied more than be-
tween 90° and 100°. At the end of three quarters of an hour,
that in the warm water had in it a coagulum as large as a
garden-pea; but that in the cold water, being let out into a
cup, was quite fluid. Twenty minutes after being exposed to
the air, that which had been in the cold water was coagulating ;
but that from the warm water neither then nor afterwards
showed any signs of farther coagulation : so that it seemed not
only to have jellied whilst in warm water, but to have begun
to part with its serum. From this experiment, it seems pro-
bable that the coldness was that property of the water to which
the lessened disposition to coagulate was owing ; but to be more
sure of this, and to see whether the blood might not be kept
fluid a longer time by these means, I tried, as follows :

EXPERIMENT XXV.

On January the 14th, I cut out a piece of the jugular
vein of another dog, and put it into oil, in which the thermo-
meter stood at 38°. At the end of six hours it was taken out,
and the red particles were observed through the coats of the
vein to have mostly settled to one side. The blood was let out

52 PROPERTIES OF THE BLOOD.

into a cup, and was found to be fluid; at the end of fifteen
minutes above one half was still fluid ; in twenty-five minutes
it seemed to be quite jellied. Now as in this experiment a
similar effect was produced, as when the vein was put into
water, it seems probable that it was the coldness of the water,
and of the oil, which had lessened the disposition of the lymph
to coagulate.

EXPERIMENT XXVI.1

Another piece of the same vein was put into river-water, in
which the thermometer stood at 38°, and was left till the next
morning; when, after twenty-two hours and a quarter, it was
taken out. The red particles did not seem to have subsided,
as in the former experiment ; but the vein being opened the
blood was found to be fluid, though so viscid that it could barely
drop from the vessel. The cup into which it was received was
placed upon the window of a moderately warm room, and was
examined carefully from time to time ; but the blood never had
any appearance of coagulation, on the contrary, it remained
fluid till it was dried by the evaporation of the water, which
happened by the next day. In this experiment the cold seemed
entirely to have prevented the coagulation of the lymph : so
ill-founded is the common opinion, that cold coagulates the
blood.

As the lymph, on being cooled, is deprived of its power of
coagulating when exposed to the air, may we not thence be led
to explain that fact mentioned by Lister, that the blood of
those cold animals which sleep during the winter-season, on
being let out into a basin, does not coagulate ? (xxvii.) And
thence, as he observes, remains always fit for motion.

1 It is necessary to observe here, that great expedition should be used in making
these experiments, for, unless the vein be cut out in a few. minutes after the death
of the animal, the experiment may not succeed, from the blood having begun to
coagulate.

(xxvii.) Mr. Huntera quotes Mr. Cornish as having seen the blood
of torpid bats in some degree coagulated, but soon recovering its fluidity
when subjected to motion and heat : Mr. Palmer adds in a note, that
Dr. Marshall Hall, in his experiments on hybernating animals, found
the blood as fluid as under ordinary, circumstances. M. Saissyb states
that the blood of hybernating animals, even during the deepest lethargy,

a Works, ed. by Palmer, vol. iii, p. 33.

b Researches Exp. sur les Animaux hybernans, p. 46, 8vo, Paris, 1808.

CHAPTER IV.

SOME FURTHER OBSERVATIONS ON THE COAGULABLE LYMPH, AND
ON THE SUDDEN CHANGES PRODUCED UPON IT.

IF the reader has been persuaded of the common opinion,
that the disposition of the blood to coagulate is increased in
inflammatory disorders, it may perhaps appear to him, as it for-
merly did to me, a very extraordinary circumstance that the con-
trary should be true (see Note xxi) ; and likewise that the blood
should in reality be the more disposed to concrete, in proportion
as the body is weakened, or as the action of the blood-vessels is
diminished (see Note xxiv). And as we are naturally tenacious
of old opinions, and unwilling to adopt new ones till fully proved,
he may suspect that there has been some fallacy in these experi-
ments. And indeed I must acknowledge that there is, in ap-
pearance, one strong argument against my general conclusion,
which is, that it has not only been remarked that the first cup
has a crust, whilst the last has none, but likewise, that the second,
or the third cup, alone shall have a crust, whilst the preceding
ones are without it. Now this, I say, seems contradictory to what
I have advanced, concerning the disposition of the blood to
coagulate being increased in proportion as the body is weakened;
for here in proportion as the blood is evacuated, its disposition
to coagulate is lessened ; since it was more sizy in the second
or third cup than in the% first. But, in answer to this objec-
tion, I must remark, that these cases very seldom occur; and
that in general the first cups are more sizy, and are the latest

is not coagulated. Dr. Davy has favoured me with the following extract
from his note-book : " March 3 1 , 1 84 1 , killed a tortoise, just then awaking
and almost torpid ; the air 50° ; air of room 55° ; temperature in recto
48° ; blood from right auricle 50° ; in left compartment of ventricle 5 1 -5°.
In the cavity of the belly a good deal of colourless fluid, which jellied
on standing. But little blood in the heart and great vessels, which, when
coagulated, was very tender, like the thinnest jelly. March 7, 1836, killed
and examined a hedgehog ; the blood coagulated slowly and feebly."

54 PROPERTIES OF

in jellying ; and when the contrary takes place, or when the
second or third cup is more sizy than the preceding, I am per-
suaded that upon a careful examination, instead of weakening,
they will be found to strengthen my inference ; as will appear
probable by the following case, which has occurred since these
experiments were published in the 'Philosophical Transactions/

EXPERIMENT XXVII.

On the 13th of June, I visited a young man, twenty -two
years old, of an athletic habit, who complained of a violent pain
in his head and back, with a full strong pulse ; but as he was
then in a profuse sweat, which had been preceded by a shiver-
ing, it was not thought proper to bleed him, and the rather, as
we were informed, that he had had a similar paroxysm two days
before. But next day, finding that his fever had not left him
with the sweat, and that he still had a pain in his head and
back, and that his pulse, though not now full and strong, yet
was quicker than natural, it was then judged necessary to take
away some blood. Upon opening the vein, the blood flowed
very slowly, and indeed merely trickled down his arm. Ima-
gining that the bandage might be too tight, I slackened it, but
still the motion of the blood was not accelerated. I then asked
him whether he had not been afraid of the bleeding, and he
told me he had ; and on feeling his pulse in the other arm, I
found it very low. I therefore desired him to move the muscles
of his hand, which he did ; but nevertheless so slowly did the
blood run, that it was four minutes before I got an ounce and
a half into a cup. I then stopped the orifice till another cup
was brought, into which the blood ran in a full stream, to the
quantity of three ounces, and that in two minutes, although the
orifice was rather small, so much was its velocity now increased.
Into the third cup, which likewise held three ounces, the blood
ran still faster, as it was filled in less than two minutes. By
this time the patient beginning to be faint, I stopped the bleed-
ing till he could lie down on the floor, and then about three
drachms more of blood were received into a fourth cup : this
came away very slowly, and the bleeding stopped of itself.
He drank a glass of water, and did not faint, and he appeared
afterwards to be much relieved by the evacuation. Upon this
blood I made the following remarks :

THE BLOOD. 55

That which was taken away last was first coagulated, and
completely too, by the time I had tied up his arm, which was
in three minutes from the blood's first running into the cup.

The blood which was received into the first cup coagulated
next, and as I observed by my watch, in twelve minutes from
its being set down on the table.

That which was received into the second cup was the third
in order as to coagulation, and was considerably later in jellying
than the first; for in fifteen minutes it was not thoroughly
coagulated ; nay, even in twenty-two minutes a small part of
it was still fluid. It was remarkable that none of these three
had any size.

But the blood in the third cup differed considerably from
that in the others ; for in five minutes it began to appear trans-
parent on its surface, an indication of a future size, and it was
later in coagulating (see Note xxi) than that in the other cups ;
for even at the end of twenty-six minutes a great part of the
coagulable lymph was still fluid, as appeared on removing the
pellicle that covered it ; but in thirty-five minutes it was com-
pletely jellied. The size in this blood was very thick and tough.

Now this case, when carefully examined, instead of being an
objection to my conclusions, will, I presume, be thought a
strong confirmation of them.

For, in the first place, as the blood in the third cup alone
had a crust, and was much later in jellying than the rest, it
strengthens my inference, that the disposition of the blood to
coagulate is lessened in those cases where the inflammatory
crust or size appears (see Note xxi). And as the blood ran more
rapidly into this cup, it showed that the heart and blood-vessels
had begun to act with greater force, and therefore confirmed the
opinion, that in proportion as these act more strongly, the dis-
position of the lymph to coagulate is diminished (see Note xxiv).
The same opinion is likewise supported by observing what
happened to the blood in -the first cup, which coagulated sooner
than that in the third, owing to the vessels then acting more
weakly, as was evident from the blood's trickling down the arm,
and from the lowness of the pulse.1

1 In like manner may be explained another variety in the appearance of the size
namely, where it is found in the first and last cups, but not in the second or third :
this, I suspect, seldom happens, but when it doe it may perhaps be found, on exami-

56 PROPERTIES OF

2dly. It may be observed, that the great difficulty in admit-
ting the conclusion made in the former part of these sheets
(viz. that the want of size in the last cup is occasioned by an
alteration in the blood-vessels) was to conceive how these vessels
could possibly alter the properties of the lymph so suddenly, as
in the time between receiving the blood into the first cup and
into the last. But this case confirms that inference, by showing
the fact in a clearer point of view ; for even here, where the
appearance of the size was reversed, it was found that the blood
which had a crust or size was latest in coagulating, and that it
was this blood which was taken out of the vessels when they
acted most strongly, as was proved by the rapidity with which
it flowed into the cup.

3dly. Since the times in which the blood jellied in these
cups were so very different (the first coagulating in twelve mi-
nutes, the second in about twenty-two, the third in thirty-five,
and the fourth in less than three minutes, notwithstanding
these cups were filled in less than two minutes after one another),
it shows, I say, how soon that state of the blood-vessels on
which the size depends, can be removed and assumed, and
therefore leads us to conclude, that although this size is in
general a sign of an inflammatory disorder, or a strong action
of the vessels (see Notes xxm and xxiv), yet there may be several
circumstances to be taken into the account, before we can judge
from its presence, or absence, whether or no venesection should be
repeated: and it likewise shows clearly, that it would be improper
to determine, from the presence of this alone, when bleeding is

nation, that the vessels were acting more weakly whilst the second or third cups were
filled. For so easily does this size appear to be removed, or formed, that I suspect
it may sometimes happen that when the blood is taken away in a full stream, from
a large orifice, the patient may be so suddenly weakened, and the properties of the
blood may in consequence be so changed by the time the second cup is filled, that
the size shall be removed ; and yet afterwards the vessels may recover their former
tone, so that the third or fourth cup may acquire a size again. Nay, I suspect that
this appearance may even be affected by the passions, particularly from observing
that the patient above mentioned, as well as others whose blood at first trickled
slowly down their arms, had been much afraid of the lancet (xxvin).

(xxvin.) See Note xxiv. Some interesting speculations on the pro-
bable modifications in the nature of the current of blood under different
degrees of vital action, are given in Dr. Davy's Researches, vol. ii, p. 83.

THE BLOOD. 57

necessary ; and yet there have been not a few who have inclined
to make such a conclusion, from their considering this crust or
size as so very morbid an appearance.

4thly, As the blood in the third cup was so late as thirty-
nve minutes in coagulating, and was sizy, whilst that in the
fourth was not so, and jellied in less than three minutes, al-
though it had been taken from the vessels only two minutes
after the other, but at the time the patient had become faint ;
it shows how much faintness and languor increase the viscidity
of the blood, and likewise its disposition to coagulate, since in
two minutes they produced such a change as to remove the
size, and to reduce the time of coagulation from thirty-five to
three minutes. It therefore shows clearly how much languor
and faintness should be encouraged in hemorrhages, and how
carefully we should avoid giving anything that can stimulate,
or rouse the patient ; that the medicines likely to be of service
are nitre and the acids ; or such as cool the body, or have the
property of diminishing the force of the circulation, or of in-
creasing that languor or faintness ;* that all agitation of mind
should, as much as possible, be prevented, lest it increase the
circulation; that all muscular motion should be avoided for
the same reason : for that an exertion of the patient's strength
can lessen the disposition of the blood to coagulate, I am per-
suaded from some of the above-mentioned cases, and likewise
from what I have observed in dying sheep, where the struggles
of the expiring animal seemed in some instances, when violent,
to alter the properties of the lymph (see Note xxiv) .

We have endeavoured to explain the appearance of the in-
flammatory crust or size, from the red globules having subsided
from the surface of such blood before it coagulated : this we
observed was partly owing to the lymph's being later in coagu-

1 It has been objected here, that nitre would seem improper for this purpose, be-
cause in experiments mentioned before (p. 12) it was found to prevent the coagula-
tion of the blood, out of the body ; but this objection is removed, by considering,
that, in order to prevent coagulation, the nitre must be used at least in the proportion
of two scruples to every two ounces of blood. But, when we exhibit it internally,
we seldom give more than a scruple every two hours, which can have no effect in
attenuating the whole mass of blood, nor in preventing coagulation, especially as we
have reason to believe its properties are changed before it passes the digestive organs.
Its good effects in hemorrhages, therefore, are probably owing to its action upon the
stomach. For proofs of its utility, see ' Medical Observations and Inquiries,' vol. iv,

58 PROPERTIES OF

lating in those cases, but principally to its being thinned.
But, we may now add, that although the attenuation of the
lymph and its lessened tendency to coagulate are connected in
most of those cases, yet they do not always go together; for
the lymph may have its disposition to coagulate lessened with-
out being thinned; which was evident in the preceding case,
on comparing the blood in the second with that in the third
cup; for the blood in the second cup had no size, notwith-
standing it remained fluid at least ten minutes after the size
had begun to appear in the third : this I attribute to the blood
in the third being more attenuated, and thereby more readily
allowing the globules to subside.

That the blood may have its disposition to coagulate lessened,
without being attenuated (xxix), is likewise probable from the
following cases.

EXPERIMENT XXVIII.

In the month of January I bled a man, who complained of
a pain in his head, attended with giddiness and shivering, a
pain and sickness at his stomach, and with a full and quick
pulse : the blood was found to remain fluid for ten minutes, and
then jellied, but no size appeared.

,-r r-.r T *•••'-'

EXPERIMENT XXIX.

In another person, who was bled merely for a drowsiness,
and because he was accustomed to that evacuation in the spring,
I found the blood remain seven minutes without coagulating,
and yet it was without any size.

Now, since in these cases the blood remained so long fluid,
and yet the red particles did not subside, or no size appeared,
I should conclude, that only the disposition of the lymph to
coagulate was lessened, without its being thinned. And from

(xxix.) Mr. Hewson infers that the blood is not attenuated because the
corpuscles do not sink in it. But the rate with which the red corpuscles
sink in a fluid may give an incorrect idea of its density or consistency.
They may even not subside at all in blood artificially made thinner and
lighter, and its coagulation somewhat retarded. If it be admitted that
the sinking of the corpuscles, during the formation of the buiFy coat,
affords an accurate means of estimating the consistency of the liquor
sanguinis, it must also be admitted that it becomes thinner some mi-
nutes after it is taken from the animal, which is not at all probable.
See Note xxiu.

THE BLOOD. 59

the last case we may likewise conclude, that although the times,
at which the blood taken from persons in health begins to
coagulate, be allowed to be about three minutes and a half, as
I have found from repeated observations, yet there may be some
variety in this respect ; for a plethora and other circumstances
may make it later in coagulating in some cases, even where the
patient is otherwise in perfect health.1

We have observed before that the size is sometimes very firm,
and at other times spongy and cellular ; these differences in its
density are, I suspect, in proportion to the degree of attenuation
and lessened disposition of the blood to coagulate ; for as the co-
agulation begins on the surface, and forms there a film which
attracts the rest of the lymph (see Note XLIV), the more that
lymph is attenuated, and the slower it coagulates, the more will
the film be able to separate it from the red globules, and from the
serum : thence perhaps it is, that when the blood, besides being
very thin, likewise jellies slowly (see Note xxi), we sometimes see
almost the whole coagulable lymph collected at the top, forming
a firm crust, which being free from the serum, as well as from
the globules, contracts the surface into a hollow form. But when
the blood has its disposition to coagulate less diminished in pro-
portion to the attenuation, then, although the globules subside
from the surface, yet the whole of the lymph jellies so soon
after the coagulation begins, that there is not time for its being
separated from the serum, of which it therefore contains a con-
siderable quantity, and is of course more spongy and cellular.

In proportion to the thickness and density of the size, the
bottom of the cake is of a looser texture ; but this looseness of
texture is not owing to putrefaction, as has been suspected, but
merely to the lymph's being collected at the top, and therefore
leaving the bottom of the crassamentum.

Notwithstanding bleeding does in general weaken the action
of the vessels, increase the disposition of the blood to coagulate,
and even thicken the lymph, yet it may happen that in the
ordinary quantity in which blood is taken away, none of these
effects shall be produced ; of this the following case seems to
be an instance.

EXPERIMENT XXX.

A woman in the seventh month of her pregnancy was bled
1 This inference is confirmed by a case mentioned below, Experiment xxxu.

60 PROPERTIES OF

for a violent pain in her side, attended with a cough ; the quan-
tity taken away was eight ounces, which was received into four
cups ; and as the orifice was small, about ten minutes were
spent in the bleeding. On attending to the different cups, I
could observe no difference in the periods at which the coagu-
lation commenced and finished in each, allowance being made
for the time the blood began to run into each. In every one
of these cups the blood was completely jellied in about twenty
minutes, and each had a crust or size nearly of the same
thickness. So that the bleeding seemed not to have produced
any change in the strength of the patient's vessels, nor was her
pain sensibly abated by it. She was therefore desired to live
low, to confine herself to a vegetable diet, and to take a scruple
of nitre every three hours in a draught of the decoctum pectorale;
and if her pain and cough were not abated in a day or two, she
was directed to repeat the bleeding. As close attendance was
not required, I did not visit her till four days after, and then
she had got free of her complaints, notwithstanding her blood
had been apparently so little changed in the time of the eva-
cuation.

In this case the bleeding seemed neither to have thickened
the lymph, nor increased its disposition to coagulate, nor
weakened the action of the vessels ; but that it generally pro-
duces these effects cannot, I think, be doubted, from our having
observed it in so many instances. Perhaps the dread of the
operation might here have made the coagulation of the blood
in the first cup approach nearer to that in the last ; or perhaps
the smallness of the orifice prevented there being so manifest
a change produced by the evacuation, from its giving time to
the blood-vessels to adapt themselves more equally to the
quantity they contained, by which means she was not weakened
by the loss of blood.

It has been observed by Sydenham (xxx) and others, that it
sometimes happens, even in inflammatory disorders, when the
blood trickles down the arm, instead of running in a full stream,

(xxx.) Sydenham, Opera Omnia, imp. Soc. Syden. 8vo, Lond. 1844,
sect. 6, cap. 3, p. 24 7. The fact was noticed, too, by Dr. Richard Davies.8

a Essay on the Blood, p. 25, 8vo, Bath, 1760.

THE BLOOD. 61

it does not acquire a crust or size.1 May not this be explained
from what is observed in the case related in Experiment xxvn ?
that is, in such instances the vessels, either from a febrile or
from some other oppression, act more weakly than they do in
the ordinary cases of inflammation ; by which means the lymph
is not sufficiently attenuated to allow the red globules to sub-
side before the coagulation begins, and therefore the size does
not appear, as in other cases of inflammation where there is no
such oppression.

As air is found to coagulate the blood and cold to thicken
it, an objection has thence been made to the conclusions from
some of the preceding experiments ; and it has been supposed
that the changes in the properties of the blood, that happen
during the time of bleeding (which I have attributed to a dif-
ference in the action of the vessels), might possibly be owing
merely to a difference in the exposition to the air or to cold (see
Notes xi and xn). For instance, since the blood that trickles
down the arm seems to be more cooled than that which flows in a
full stream, it has thence been supposed that its want of size, in
those cases, might be owing to the exposition to the air, which
made it coagulate sooner, and to the cooling which had thick-
ened it, and thereby prevented its red particles from subsiding, so
that the size should be formed. This objection is indeed plausible,
and to those who have not seen these experiments might at first
seem sufficient to explain the appearance ; but upon further ex-
amination it will not be found to do it satisfactorily. Thus, for
example, although it be true that air coagulates the blood, and
likewise cools it, yet there are changes remarked in the preceding
experiments that cannot be explained merely by a difference in
the exposition to the air : thus, in Experiment xxvn, the blood

1 It may be necessary to observe, that it is not in every case where the blood
trickles down the arm that it is without a size ; on the contrary, it sometimes happens,
that even in such circumstances it has a very dense one ; an instance of which may
be seen below, in Experiment xxxi. In those cases the trickling down the arm may
perhaps be owing to some circumstance in the orifice preventing its flowing in a full
stream, or to a difference in the tightness of the ligature, rather than to a weak
action of the vessels. Or, although the size be occasioned by a strong (or some par-
ticular mode of) action of the vessels, and therefore is removed by weakening them,
yet it may not always be removed immediately on their being weakened. For it may
happen, that in some cases the lymph may not be so susceptible of changes as in
others ; or when it has been very much attenuated it may not again be thickened
immediately, on the vessels acting weakly.

62 PROPERTIES OF

in the third cup was thirty-five minutes in being completely
coagulated, whilst that in the fourth, although taken from the
arm only two minutes later, yet coagulated in three minutes.
Now no exposition to the air nor to cold, from the blood's
trickling down the arm, could produce such a change. Of this
I am persuaded from what I have observed on comparing the
blood received into a cup with that which dropped on the plate
which held the cup ; for I have repeatedly seen on those oc-
casions that the blood on the plate, although it was so much
more cooled and so much more exposed to the air than that in
the cup, yet instead of coagulating proportionably sooner, was
later in being coagulated. The following experiment shows this
clearly.

EXPERIMENT XXXI.

A young woman with a violent inflammation in her eyes, was
bled on the fifth of March, early in the morning, before she had
breakfasted, and whilst she was complaining of a sickness at her
stomach; the blood followed the lancet in a stream, but im-
mediately after it only trickled down the arm, and continued to
do so during the whole of the evacuation. About eight ounces
of blood were taken away into four vessels, viz., into two cups
and two saucers, in the following manner : A plate holding both
a cup and a saucer was held under the arm, and the blood was
first received into the saucer, to the quantity of a spoonful, then
as much more was received into the cup that stood by it ;
then again the blood was suffered to run into the saucer, and
afterwards into the cup, and so alternately till there was about
two ounces in each, when they were carefully set down on a
window where the thermometer stood at 57°; the plate was
placed by them, and contained about a spoonful of blood, which
had missed the saucer in the begining of the evacuation. Next,
the second plate was brought, and some blood was received first
into the cup and then into the saucer, in the same manner ;
and three portions of blood were suffered to drop at different
times on the plate, each of them about the breadth of a shilling.
Now, here, according to the reasoning in the objections made
to some of the preceding experiments, the blood in the saucers
having twice as much surface as that in the cups, ought to have
coagulated in half the time ; and that on the plates ought, from

THE BLOOD. 63

the largeness of the surface, to have coagulated in much less
time; but just the contrary happened; for the blood in the
cups was first completely coagulated, that in the saucers next,
and that on the plates latest of all. But, as the experiment
seems curious, it may be proper to give a more particular detail
of what was observed.

On looking at the first plate, at the end of seven minutes
after it was set down on the window, the surface of the blood
in the cup was considerably transparent, and a pellicle (that is
the surface beginning to coagulate) was formed upon it ; but
no transparency was distinguishable on that in the saucer, nor
could any pellicle be observed upon drawing a pin through it,
or through that which had dropped upon the plate. At the
end of fifteen minutes the blood in the cup and in the saucer
was pretty much coagulated, or had a thick pellicle, whilst none
could yet be observed on that upon the plate. At the end of
fifty -five minutes that in the cup was just beginning to part
with its serum, whilst the blood in the saucer was not yet com-
pletely coagulated; for on inclining it to one side, apart of the
blood appeared fluid under the pellicle. That on the plate was
now coagulated. They were all three sizy ; and the blood in
the saucer had a size which seemed to be as firm and in as large
a quantity nearly as that in the cup ; and the size upon the blood
in the plate was thick enough to be easily distinguished.

In the second plate, at the end of seven minutes after being
set on the window, both the blood in the cup and in the saucer
was beginning to coagulate ; and had a pellicle of a considerable
thickness, and were both sizy ; but no pellicle appeared on any
of the three portions that had dropped on the plate. At the
end of fifteen minutes, that in the cup was firmly jellied, that
in the saucer not quite so much, and one of the spots on the
plate was but just beginning to coagulate at its edge. At the
end of twenty-five minutes, the two last spots were still per-
fectly fluid, but in twenty-eight minutes they were beginning
to coagulate ; whilst the blood in the cup was now parting with
its serum. At the end of fifty minutes a considerable quantity
of serum had separated in the cup, and the separation was just
beginning in the saucer.

This experiment was repeated on another person's blood two
days after, in the presence of Mr. Field and Mr. Hendy, two

64 PROPERTIES OF

studious gentlemen, at that time living at the Middlesex Hos-
pital, and the appearances were exactly similar : and it was
evident to them that the blood in the saucers was later in co-
agulating than that in the cups, and that on the plates (one of
which was of pewter) was considerably later in jellying than
that in the cups or in the saucers.

These experiments therefore show clearly, that the differences
in the periods of coagulation, and in the appearance of size
upon the blood received into the different cups in bleeding,
cannot be accounted for from a difference in the exposition to
air ', for here blood more exposed to the air than that is which
trickles down the arm is found equally sizy, and to be even
later in coagulating than blood less exposed.

As we have here observed a new circumstance that appears
remarkable, and which at first sight seems not reconcilable to
some of our conclusions, it may therefore be necessary to examine
it farther, or to inquire, if air be a coagulant of the blood (as
we have endeavoured to prove in the beginning of this Essay)
how comes it that in this experiment the blood was not coagu-
lated proportionably to its exposition to the air ? This, I think,
may be explained from considering another fact that was men-
tioned in the preceding pages, viz. that cold lessens the blood's
tendency to coagulation. The blood, therefore, in the saucer,
although it was more exposed to the air, yet being more cooled
than that in the cup, was for that reason later in coagulating ;
and that on the plate, which was most exposed to the air, being
most cooled, was therefore latest of all.

But we may add, that although it be evident from this ex-
periment, that the difference in the exposition to air, or to cold,
is not sufficient to explain the changes which we see produced
upon the blood, in so little time as in the filling of a small
cup, especially when those changes are so great as what are
mentioned in Experiment xxvn (where the blood in one cup
was thirty-five minutes in coagulating, and had a very thick
size, whilst that taken away soon after, coagulated in three mi-
nutes, and was without a size) yet, I think, that the effects of
air and of cold are considerable enough to deserve to be taken
into the account in some cases, where the changes on the blood
are not so great. For as cold thickens the blood, it is probable
that in some cases where the lymph is but little attenuated,

THE BLOOD. 65

and where therefore, in the ordinary manner of bleeding, there
would have appeared but very little size, such blood, if more
exposed to the air so as to be sooner cooled, may thereby have
the small degree of attenuation counteracted, or removed, and
the red particles may be prevented from subsiding. So that
although in this experiment, where the size was thick, it ap-
peared equally in the saucer as in the cup, and even appeared
on the blood upon the plate; yet, if we repeat these experi-
ments on a variety of subjects, it is probable that we may
sometimes find the saucer without a size, whilst the cup has
one ; for when the lymph is but little attenuated a slight cause
may thicken it again ; and its being a little more cooled in the
saucer and on the plate may in some cases be sufficient to
prevent the size from appearing.

It has likewise been suggested, that possibly there might be
some difference in the orifice from which the blood flowed, to
which its different appearances in the several cups might be
owing. But there does not seem to be any foundation for this
objection, and it may, I think, be removed by a careful exami-
nation only of some of these experiments, particularly the 27th ;
for there the blood ran into a full stream both into the second
cup and into the third, the orifice being apparently unaltered,
and yet there was a great difference in the appearance of the
blood : for that in the third cup had a thick size, but that in
the second had none. So that there does not seem to be any cir-
cumstance attending these experiments that can explain the
changes produced upon the blood in the time of bleeding, ex-
cepting that to which I have attributed it, viz. a change in the
strength of the blood-vessels, or in their mode of action ; and
every observation I have yet made confirms me in that opinion.

A very eminent physician,1 after reading the first edition of
these sheets, informed me, that from a suggestion which he
met with in Professor Simson's Dissertations, viz, "That a
ligature on the arm wo.uld produce a size,"3 he had been for
many years cautious how he took any indications from this ap-
pearance of the blood, and desired I would endeavour to deter-

1 Dr. Fothergill.

2 Dr. Simson's observation is, that if a tight ligature be made on the limb, and the
vein opened three hours after, a size will be produced. Vide ' De Re Medica,'
Dissert, iii, § 38, p. 112.

CG PROPERTIES OF

mine, by experiment, whether the ligature being a longer or
shorter time upon the arm, even in the ordinary way of bleed-
ing, might not influence this appearance of the blood. And
accordingly, in the presence of Dr. Drummond, Mr. Field, Mr.
Hendy, and Mr. Cockson, I made the following experiment :

EXPERIMENT XXXII.

On the 9th of October, I tied up both the arms of a healthy
young man with a degree of tightness sufficient to make the
veins swell and become turgid, whilst the pulse remained free;
a vein in one arm was opened immediately after making the
ligature, and an ounce of blood was received into a cup. I
chose to take away so small a quantity that there might be the
less probability of producing any change upon the blood by
weakening the body. The ligature was left upon the other
arm for an hour, which made the veins very turgid, and like-
wise made the person complain of a stiffness in his fore-arm ;
the artery in his wrist being felt all the time, but less distinctly
than in the other arm which was without a ligature. At the
end of an hour this vein was opened, the orifice was large, and
an ounce of blood was taken away. Upon attending carefully
to each cup, it did appear that the ligature had produced some
change; for in the first place, the blood which had been so
long detained in the arm by the ligature was darker coloured
(xxxi), or blackish, whilst that from the other arm was more
florid, even at its first running from the vein. 2dly. The blood
that had been so long in the arm was rather later in being
coagulated ; for it did not begin to part with its serum till at
the end of thirty-seven minutes after puncturing the vein;
whilst in the other the coagulation was completed, and the
serum was beginning to ooze out in thirty minutes. 3dly. The
blood which was first taken away was without a size, whilst
that which had been so long in the other arm had a small
spot about the breadth of a silver penny, and did not cover a
twentieth part of the surface.

From this experiment, therefore, it would seem that a liga-
ture long continued may produce a size, agreeably to Dr.

(xxxi.) The darkening of blood by its stagnation in the living body,
is mentioned in Note v.

THE BLOOD. 67

Simson's observation (xxxii), but then it will probably be only
in small quantity.

The same learned gentleman, on being informed of the re-
sult of this experiment, ingeniously suggested that the quantity
of blood which I had taken away might perhaps be too little to
make the experiment decisive ; for, as only one ounce of blood
had been taken from each arm, all that blood might be supposed
to have been contained in the veins themselves ; and as it was
more probable that the disposition to size took place in the
arteries, a larger quantity should be taken away, in order to
judge whether the blood in the arteries had not been changed
by the veins of the arm being so long compressed.. The ex-
periment was, therefore, repeated upon the same person, on the
7th of March, Mr. Field and Mr. Hendy assisting me as
before, and we observed as follows :

EXPERIMENT XXXIII.

The blood from the arm first opened was in quantity about
ten drachms, had no size, but was late in being completely co-
agulated. The pellicle first appeared on its surface six minutes
after opening the vein, and at the end of fifteen minutes a con-
siderable quantity of the blood was still fluid ; but in thirty-four
minutes it was completely coagulated. The serum did not begin
to ooze out till at the end of fifty minutes.

After the other arm had been tied up an hour, the vein was
opened, and about ten drachms of blood were received into the
first cup, as much more into a second, and about an ounce
and a half upon a pewter plate, and about two ounces and a
half into a third cup (in all six ounces and a half) ; and it was
observed that the blood in the third cup and that in the second
coagulated in about twenty minutes, and the serum began to

(xxxu.) Thomas Simsona thought that the buffy coat is formed of
crude chyle not yet converted into blood ; and that the buff appears
after putting a ligature for three or four hours on the thigh or arm,
because the assimilation of the chyle with the blood is thus prevented.
Mr. Heyb found that neither the tightness of. the ligature, nor its longer
continuance than usual on the arm, caused the blood to become buffy.

a DeRe Medica, 8vo. Edin. 1726, Diss. b Obs. on the Blood, 8vo, Lond. 1779,
iii, $38, p. 112. p. 65.

68 PROPERTIES OF

ooze out in twenty-five minutes after opening the vein ; the
blood on the plate was later in coagulating, and none of these
portions of blood had the least appearance of size. But the
blood in the first cup was considerably, the latest in jellying ;
for at the end of twenty-five minutes a large quantity was still
fluid under the pellicle, and even at the end of fifty minutes
the coagulation was incomplete. This blood seemed to have
rather more size than that in the former experiment, but it was
not collected at one part, but was diffused over the surface, and
appeared in spots not bigger than pins' heads.

The result, therefore, of this experiment was similar to the
preceding. The ligature long continued produced a size, but
in small quantity; and therefore it does not appear probable,
that, when the ligature has been only a few minutes on the arm
(as is the case in the ordinary manner of bleeding), it can de-
serve to be taken into the account, when we judge of the dis-
ease, or of the indications of cure from the appearance of the
size; especially when it is considered that the blood on which
these experiments were made was very favorably circumstanced
for Dr. Simson's opinion; that is, it was from a patient who
seemed to be plethoric, by the blood which was first taken away
not jellying in less than thirty, and thirty-four minutes, which
is later than ordinary, as appears from what is observed above,
page the 35th ; where we found, that the blood of people in
health commonly jellies in seven or eight minutes.

As many of these experiments show how easily the disposi-
tion of the lymph to coagulate can be altered, even by slight
changes, as it would seem, in the state of the blood-vessels,
they help us to explain how it should happen, that the blood,
in some diseases, is found without this property of • jellying ; an
instance of which is mentioned by M. de Senac1 ; another

1 Traite du Coeur, torn, ii, p. 129 (xxxm).

(xxxm.) Senac's case3 is as follows : " Un homme de trente-cinq ans
avoit une ancienne galle, je le fit saigner, son sang ne se figea point."
In most of the instances observed by Dr. Davy,b in which the blood
was liquid after death, and without the power of self-coagulation, the
fatal event was referrible either to drowning, hanging, the fumes of
charcoal fire, or effusion of blood into the bronchia or air-cells.

A man aged 35, and his three children, aged \\, 4J, and 6^ years,

a Ed. 1749, t. ii, p. 129. b Researches, Physiol. and Anat. ii, 192.

THE BLOOD. 69

was observed by the learned Professor Cullen ; and a third I
saw lately by the favour of Dr. Huck and the physicians of the
British Lying-in Hospital, who, having bled a woman in a fever
that came on soon after delivery, found her blood did not
coagulate on being exposed to the air, but appeared like a
mixture of the red globules and serum only, the globules having
subsided to the bottom in the form of a powder. She died
three days after, and, upon opening her, we found the blood
had coagulated in her vessels after death, and that a tough
white polypus was formed in each auricle of the heart, one of
which I have now by me. I examined the blood taken away
before she died, and found, on exposing it properly to heat, that
it did not coagulate sooner than serum commonly does, nor
under 160° ; so that it is probable that, at the time she was
bled, her blood either was without the coagulable lymph, or its
properties were changed.

were suffocated in a burning house in Crawford street, March 23, 1846.
One of them was scarcely burned at all, and none of them sufficiently
so to cause death. Through the kindness of Dr. Boyd, I had an oppor-
tunity of examining the hodies at the St. Marylebone Infirmary, 48 hours
after the fatal event ; the temperature of the air was 50°. In the heart
of every one of them the blood was fluid, without the smallest clot ; nor
did the blood ever coagulate after having been set aside in cups for obser-
vation ; the fingers were contracted, and all the limbs rigid ; the bodies
fresh, and remarkably free from disease.

A coachman, aged about 55, hung himself; he was cut down, dead
and stiff, from six to ten hours afterwards, and examined by Dr. Boyd
and myself. The blood was fluid in the heart and veins, except two
or three very soft clots, so small and nearly diffluent that they were
only found after a search ; there was no further coagulation of the
blood when it was set apart in a cup. In the above instances, this
blood was examined from time to time for about twenty hours. But
the observations of Dr. Pollic induce him to believe that no blood be-
comes putrid before it has coagulated ; and that in cases in which its
property of self-coagulation has been supposed to be wanting, the blood
has not been kept long enough for an unusually slow coagulation to
take place. A mixture of salt and blood, which will keep fluid and
fresh for months, readily putrefies after it has been made to coagulate
by diluting it with water (see Note vn). In kittens killed by hanging
and by drowning, I have seen coagulated blood in the heart, and the
limbs rigid ; in a dog killed by hanging, as. mentioned in Note cxxxn,
there were some soft clots in the splenic blood.

The causes commonly said to prevent coagulation are mentioned hi
Note xn.

c Mr. Paget's Reports, Br. and For. Med. Rev. xix, p 253, and xxi, p. 543.

70 PROPERTIES OF THE BL001).

After a blow or contusion, the blood now and then bursts
from the vessels into the cellular membrane, sometimes form-
ing an ecchymosis, and sometimes a tumour, and it is a question
with some, whether such blood coagulates or not ; but that it
coagulates in most of these cases, is proved by opening such
tumours. Yet it has likewise been observed, that now and
then these tumours have been attended with a fluctuation, and
that, after some time, their contents have been absorbed, and
it has also been found that, upon opening some of them, even
several weeks after the accident, the blood was fluid. In such
cases the blood had probably undergone a change similar to
what was observed to take place in some of the preceding
experiments, that is the lymph had been deprived of its pro-
perty of coagulating (xxxiv), in passing from the blood-vessels
into the tumour : a circumstance, which, how remarkable soever
it may appear, agrees with what we have above observed of the
lymph, whose properties seemed to vary with -the state of the
blood-vessels (see Note xxiv).

(xxxiv.) Extravasated blood, which has long remained fluid in a
bruised part, may yet coagulate when let out (see Note x).

CHAPTER V.

CONTAINING A RECAPITULATION OF THE PRINCIPAL .FACTS AND
CONCLUSIONS THAT ARE MENTIONED IN THE PRECEDING PAGES.

THE separation of the blood into crassamentum and serum,
in a given time, appears to be in proportion as the heat in
which it stands is nearer to that of the human body (xxxv).
The heat in which the blood is kept should therefore be at-
tended to, when we draw inferences from the proportions of
these two parts. .

The florid colour of the surface of the crassamentum seems
to be owing to the air. The venous blood, in passing through
the lungs, has a similar change produced upon it, or becomes
more florid by the time it gets into the arteries; and this
florid colour is again lost in passing from the small arteries into
the veins, especially if the person be in health. But some-
times in diseases it does not undergo this change, but comes
florid out of the veins (xxxvi).

Neutral salts, on being mixed with the blood out of the
body, make it more florid : they likewise, if used in great
quantity, prevent its coagulation when exposed to the air, and
some of them allow the lymph to be precipitated, or to jelly on
being diluted with water (xxxvn). But we are not to con-
clude from thence that they would produce the same effects
when used as medicines ; for then they are only given in small
quantities (xxxvin), and may have their properties changed

(xxxv.) See Notes u and in.

(xxxvi.) On the colour of the blood, see Notes iv and v.

(XXXVIT.) The effects of neutral salts on the colour and coagulation
of the blood are discussed in Notes iv, vi, and vn.

(xxxvin.) A very weak saline solution will prevent that aggregation
of the corpuscles, which is characteristic of the blood in inflammation.
The effect may be easily tried on the regularly buffy blood of the
horse (see Note xxni). On the different effects of different quantities of
salt on coagulation, see Note vn.

72 PROPERTIES OF

by the digestive organs, before they are mixed with blood.
And as they are most of them cooling and sedative, they pro-
duce nausea and languor of the stomach, and lessen the force
of the vascular system. And as the properties of the blood
seem to depend upon the action of the vessels (see Note xxiv),
these salts may thus, by affecting the vessels, produce changes
on the blood very different from what might have been sus-
pected, from observing what takes place when a large quantity
of them is mixed with the blood out of the body. •

The blood is not coagulated (I do not mean thickened, for
it is indeed thickened) by cold, but on the contrary, has its
disposition to coagulate lessened, and even entirely taken off,
if the exposition to cold (xxxix) be long continued. When
therefore the blood in the basin jellies, it is not the cold that
produces this effect, nor is it the want of motion ; for although
the blood by being at rest will jelly at last, yet it will not
do it in the time the coagulation takes place in the basin;
which in the blood of healthy persons is in seven or eight
minutes after being received from the vein. The coagulation
of the blood in the basin is therefore probably owing to the
air (XL).

When the blood is at rest in the bo$y, it will at last coagu-
late merely for want of motion ; but this coagulation takes
place with different appearances from that of the blood in a
basin, for it begins in ten or fifteen minutes, and is not com-
pleted in three or four hours ; whilst the blood of the same
animal, taken out of the veins, and exposed to air, will begin
to jelly in three or four minutes, and will be completely jellied
ia seven or eight (XLI).

The effect that air has upon the blood is not immediate
on its application, but takes place sooner or later, in different
circumstances of health ; in some cases the blood is coagulated
in a few seconds after it has been exposed to the air, in others
not in less than an hour and a half, or perhaps more, as appears
from Experiment 14th.

(xxxix.) Concerning the effects of a low temperature and of freezing
on coagulation, see Note xi.

(XL.) The effect of air on coagulation is mentioned in Note xn.

(XLI.) On the effect of living tissues on coagulation, see Note xui ;
on the slow coagulation of the blood in the body after death, see Note x.

THE BLOOD. 73

The inflammatory crust or size is not a new-formed sub-
stance (XLII), but is merely the coagulable lymph separated
from the rest of the blood. This separation seems to be occa-
sioned by the lymph being attenuated (XLIII), by which means
the red particles soon settle to the bottom, and leave the sur-
face of the blood transparent ; and this transparent part being
a mixture of the coagulable lymph and the serum, the former
coagulates on its surface where, in contact with the air, and the
disposition to coagulate being likewise diminished, the blood
remains a long time fluid, and thereby gives time for the pel-
licle formed on its surface to attract the rest of the lymph, and
to collect it at the top, leaving the bottom of the cake propor-
tionably softer (XLIV). The size therefore is thicker and
denser, in proportion as the lymph is thinned (XLV), and is less

(XLII.) Dr. Benjamin G. Babingtona concludes that fibrin and serum
do not exist as such in the circulating blood, but that this is composed
only of corpuscles and of a homogeneous liquor sanguinis ; that there
is no such animal fluid as coagulable lymph, since the liquor sanguinis
is essentially liquid, separating indeed under certain conditions into two
parts, of which one only is spontaneously coagulable ; and that there is
no better reason for affirming that fibrin exists in a fluid state in the
liquor sanguinis than for affirming that muriatic acid exists in a solid
state in muriate of ammonia. But it is difficult to reconcile Dr. Ba-
bington's conclusion with the fact, admitted by him, that serum differ-
ing very little from that of the blood, and unaccompanied by fibrin, is
not unfrequent in the serous cavities ; which fact, as Dr. Davy remarks5,
agrees with the opinion of Hewson and Hunter, that the fluid part of
the blood is an equable mixture of lymph and serum, one spontaneously
coagulable and the other not. The specific gravity of some pellucid
serum which I took from a hydrocele was as high as 1024-

(XLIII.) See Notes xxm and xxix.

(XLIV.) The influence here attributed to the attraction of the pellicle
is doubtful, because the rising of the fibrin, and the difference of con-
sistency in the upper and lower parts of the clot, may be accounted for
by the sinking of the corpuscles. When the liquor sanguinis of the
horse is removed from the corpuscles, and allowed to coagulate in a
tube, I find that the upper and lower parts of the clot do not differ in
consistency. The observations of Dr. Davies on the specific gravity of
the different parts of the blood are noticed in the Introduction. Dr.
Davyc found the specific gravity of a mixture of human red corpuscles
and serum, obtained by straining the broken-up clot through linen, to
be 10/4 ; of the cruor drained of serum 1087 ; of the bufly coat, by
weighing, 1060; of the corpuscles, by immersion in a saline solution,

a Med. Chir. Trans, vol. xvi, p. 301. c Researches, Physiol. and Anat. ii, 17-20.
b Researches, Physiol. and Anat. ii, 21.

74 PROPERTIES OF

disposed to concrete (XLVI). But it is not a certain sign of
inflammation, and does not appear to be the cause of that dis-
ease, but only its effect.

But the most remarkable conclusion that these experiments
have led to is, that the properties of the blood depend on the
state of the blood-vessels, or that they have a plastic power over
it, so as to be able to change its properties in a very short
time (XLVII). The novelty of this opinion, and the difficulty
of conceiving how the vessels should have so remarkable a
power, has made some object to the conclusion, who had not
well considered all the facts from which it was deduced. I
shall here therefore sum up these facts.

That the blood-vessels, by their stronger or weaker action,
can change the properties of the lymph, even in the short time
spent in filling the different cups in bleeding, is first inferred
from Experiment 19th, where the blood in the first cup had a
size, whilst that in the others had none. Now as this want of
size in the last cups was owing to the lymph having by this
time become thicker, and to its being more disposed to coagu-
late, and no other circumstance being observed that could
account for this alteration (for the difference in the expo-
sition to cold or to air even then appeared inadequate to the
effect, and are now proved to be so by Experiment xxxi), I
concluded, that it was entirely owing to an alteration in the

1132. Dr. Benj. Babingtona estimated the specific gravity of fibrin at
1079, by putting it into a saline solution. But this estimate is proba-
bly too high ; for a strong solution of salt may increase the specific
weight of the fibrin, by depriving it of some of its natural moisture.
Thus I have ascertained that a slice of the buffy coat of the horse's
blood will float at first and afterwards sink in a solution of nitre, sp.
gr. 1 132 ; in a solution of Glauber's salt, sp. gr. 1084 ; and in a solution
of muriate of soda, sp. gr. 1 176. After the fibrin had been some weeks
in these solutions their specific gravity became diminished, that of the
nitre, for instance, being 1108, no doubt in consequence of the
moisture extracted from the fibrin. In every instance they were
weighed at a temperature of 60°. The fibrin did not appear to be at
all dissolved. The objection of Dr. Babington to calculating the weight
of the corpuscles by immerging them in saline solutions, entirely agrees
with my own experience : (see Notes xxm and xxix).

(XLV.) See Notes xxm and xxix.

(XLVI.) See Note xxi.

(XLVII.) See Note xxiv.

a Cyclopaedia of Anat. and Physiol. i, 418.

THE BLOOD. 75

strength with which the vessels acted upon the blood. And
to this opinion I was led by the well-known fact, that bleed-
ing weakens the body ; and as bleeding which weakens the
body had here removed the size, by thickening the lymph,
and by disposing it more to coagulate, I thence inferred that
it was by its weakening the body, or the action of the
vessels, that it had produced those changes on the lymph.
The consideration of what takes place in inflammations con-
firmed me in this opinion; for in them the blood-vessels are
known to act more strongly, and it is proved above, that the
lymph is proportionably thinned, and has its disposition to
coagulate proportionably diminished (XLVIII).

And this opinion was further strengthened by observing
what occurs when an animal is bled to death, or when the ves-
sels are acting with the lowest degree of strength ; for here it
was found that, in proportion as the strength of the animal was
reduced, the blood was more and more disposed to coagulate

(XLIX).

And having thus observed the connexion between the altera-
tions in the lymph and changes in the strength of the blood-
vessels in these cases, I next inferred there might be the same
correspondence, even in others where the changes in the pro-
perties of the lymph are more sudden, as in Experiment 27th,
where there was no size in the first cup, but a thick one in the
third ; and even this case, when carefully examined, confirmed
the inference ; for the blood-vessels were found to be acting
with different degrees of strength, at the very time that the
lymph was found to have different properties. And the only
difficulty that remained here was to explain how it should
happen that the first cup, contrary to what in general takes
place, should have its blood coagulated in less time than the
second or third ; and this I concluded was owing to some
febrile cause affecting or oppressing the patient, in which con-
clusion I am confirmed by the fact admitted amongst physicians,
that the pulse is frequently oppressed in inflammatory dis-
orders, and rises in strength in proportion as blood is taken
away.

(XLVIII.) See Notes xxi, xxm, and xxix.
(XLIX.) See Note xxiv.

76 PROPERTIES OF

From this conclusion I went further, and conjectured that
even temporary exertions of strength in the blood-vessels might
alter the properties of the lymph ; to which opinion I was led
by having observed the blood sizy in the case mentioned in
Experiment 20th, where great weakness soon followed the eva-
cuation ; and likewise from having observed, that the struggles
of dying sheep seemed to alter the lymph (L).

So that upon the whole the opinion agrees with all the ap-
pearances, and is supported by all the differences in strength
that occur in the various deviations from the standard of health :
for when the vessels act more strongly than they do in health,
the lymph is proportionably more thinned, and is less disposed
to concrete; and when the vessels act more weakly than in
health, then the lymph is proportionably thickened, and is more
ready to concrete. Is it not therefore probable that the dif-
ferences we observe in the thickness or thinness of the lymph,
and in its being more or less disposed to coagulate, are owing
to these differences in the strength of the blood-vessels ? For
such alterations in the strength of the blood-vessels are always
connected with those of the lymph, and we can observe no other
circumstance connected with those changes of the lymph that
can at all explain them.

And although it must be admitted that it is very difficult
to conceive how the blood-vessels should do this, yet I should
hope that ingenious men would not merely on that account
reject my conclusion ; but would consider, that as it is deduced
from a number of experiments, as it agrees with all the appear-
ances, and as it leads to an explanation of many of them which
we cannot otherwise account for, it may be well founded, al-
though it be difficult to be conceived ; for there may be powers
in the animal economy that are not yet dreamt of in our phi-
losophy.

This observation of the properties of the blood depending
on the state of the vessels, besides explaining many morbid
appearances, leads to a further application ; for we may thence
be led to advance more rational and more certain rules for the
treatment of hemorrhages. For as hemorrhages seem to be
stopped, partly by a contraction of the bleeding orifices, and

(L.) See Note xxiv.

THE BLOOD. 77

partly by the coagulation of the blood, and as the disposition
of the blood to coagulate is increased by weakening the body,
and likewise the contraction of the bleeding orifices is promoted
by the same means, it is therefore evident that the medicines
to be used should be such as cool the body, and lessen the
force of the circulation; and experience teaches us, that such
are the most efficacious (LI).

It likewise shows that all agitation of mind arid all bodily
motion should as much as possible be prevented; because they
increase the force of the circulation, and are thence unfavor-
able to the stopping of the hemorrhage. But that languor and
faintness being favorable to the coagulation of the blood, and
to the contraction of the bleeding orifices, should not be coun-
teracted by stimulating medicines, but on the contrary, should
be encouraged. And as evacuations weaken the body more
when they are sudden, we see a reason why bloodletting should
be advisable in hemorrhages, and why a large orifice should be
preferable to a small one, when we want to produce that languor
or faintness, or that weak action of the vessels, so useful for the
stopping of the hemorrhage.

Before we conclude, it may be added that the practice here
proposed is far from being new or uncommon ; but as some
have recommended opposite methods, and both parties have
appealed to experience, where authority so equally balances
authority, the young practitioner must be at a loss which to
follow, and for want of principles to direct his choice may fre-
quently adopt the worst practice : witness the use of port wine,
and other stimulating astringents, which is so very common in
most parts of England.

(LI.) See page 47.

CHAPTER VI.

OF THE SERUM OF THE BLOOD, AND PARTICULARLY OF THE
MILK-LIKE SERUM.

THE serum, when separated from the crassamentum, by let-
ting the blood rest in the basin into which it is received, is a
fluid, apparently homogeneous and transparent, of a yellowish
colour, saltish to the taste, in consistence thicker than water,
and its specific gravity, according to Dr. Jurin, is to water as
1030 to 1000 (LII).

When chemically examined the serum is found to consist of
a mucilaginous substance, which is dissolved in a water that
contains a small quantity of neutral salts. The mucilaginous
substance of the serum agrees with the coagulable lymph of
the blood in being fixed or coagulated by heat ; but the degree
necessary for the coagulation of the serum is greater than
that which is necessary for fixing the lymph, for the lymph is
coagulated by a heat between 114 and 120J degrees of Fahren-
heit's thermometer (see Experiment 9th) ; whilst the serum
requires 160° to coagulate it (LIII) : (see Experiment 10th).

(LII.) Dr. Jurin's estimate* is probably rather above the mean. In
five trials, Dr. Marcetb found the specific gravity of serum of human
blood from 1024-5 to 1032'5. Serum of the blood of different animals,
Dr. Davyc found to vary between 1020 and 1031 ; and of man labouring
under disease, from 1021 to 1033. In soldiers bled for slight ailments,
I have seen the serum 1025, 1026, 1028, 1029, and 1031; in all these
instances the blood had a healthy appearance. The specific gravity of the
serum of buffy blood is mentioned in Note xxii. The following num-
bers show the mean of Dr. Davy's observations on the sp. gr. of the
blood and of the serum of mammalia :

Arterial blood . 1050 Venous blood . 1053

Arterial serum . 1022 Venous serum . 1026

(LIII.) On the heat most favorable to the coagulation of fibrin, see
Notes in and xvi ; and on the coagulation by heat of serum, Note xvu.

a Phil. Trans. 1719, xxxvi, 1007. c Researches, Physiol. and Anat. ii, pp.

b Med. Chir. Trans. 1813, ii, 366. 17-25, 34-39.

PROPERTIES OF THE BLOOD. 70

But the degree of heat necessary for their coagulation is
not the only circumstance in which the lymph differs from the
mucilage of the serum ; they differ more remarkably in the
former coagulating when exposed to air, whilst the serum un-
dergoes no such change.

When the serum is coagulated by heat, a watery fluid can
be pressed out of it ; and this fluid the learned M. de Senac
distinguishes by the name of serosity (LIV).

This serosity contains the neutral salts of the blood, and
although it has been exposed to the heat of boiling water, yet
it still contains a part of the mucilaginous substance, which is
combined with the water in such a manner as not to be coagu-
lated by the heat of boiling water, till a part of the water is
evaporated by boiling ; and then it coagulates, and appears
not very much unlike the mucus spit up from the aspera arteria
in a morning.

When the mucilaginous part of the serum has been coagu-
lated by heat, it cannot again ' be dissolved in the serosity,
except by putrefaction or by the addition of some chemical
substance, and then it differs from what it was before, particu-
larly in its not being coagulable by heat.

But if the serum be exposed to a less degree of heat than is
required for its coagulation, for example, to that of 100°, it is
gradually inspissated into a brownish solid mass, and this mass
can readily be dissolved again merely by the addition of water ;

(LIV.) Mr. Huntera claimed the discovery of the serosity. But it
was probably known before 1760 ; for in that year Dr. Butt distinctly
mentioned the serosity, and referred inaccurately concerning it, like
Mr. Hewson afterwards, to Senac, as I have more fully explained in the
Introduction. Dr. Cullenb described the properties of the serosity
more perfectly. Mr. Hunter subsequently made many experiments on
it; he believed, but .by no means proved, that it is identical with the
gravy of cooked meat, and observed that more gravy is contained in the
meat of old than of young animals. The serosity is probably only the
serum wanting the albumen which has been coagulated by heat ; so
that, caeteris paribus, the weaker the serum in albumen the more serosity
there would be.

Dr. Bostockc has given the best account of the serosity, and full re-
ferences to the observations of others on the subject.

a On the Blood, pp. 17, 32-4. 4to, c An Elementary System of Physiology,
Lond. 1794. i, 473, 2d ed. 8vo, Lond. 1828.

b Institutions of Medicine, § 252, 2d ed.
8vo, Edin. 1777.

80 PROPERTIES OF

and the serum seems to possess the same properties that it did
before, particularly it is capable of being coagulated by heat.
But care must be taken not to add more water than it had
lost, for if more be added than was evaporated, it alters its
properties of coagulation.

In this circumstance of being inspissated, and again ren-
dered dissolvable in water, the serum agrees with the white of
an egg,1 but differs from the coagulable lymph, which even
when mixed with a neutral salt (viz. true Glauber's salt), can-
not be inspissated and dissolved again without coagulation.

If fresh serum be diluted with an equal quantity of water,
and then exposed to heat, it does not coagulate in that of
160°, as when undiluted (see Note xvu), nor even in the heat
of boiling water, as I have lately observed, but it can now
be boiled without immediately coagulating. And as the water
evaporates, a pellicle is formed on the surface, which be-
comes thicker and thicker as the evaporation advances. This
pellicle seems to be the mucilage coagulated, for it cannot
again be dissolved in water like the inspissated serum.

Milk, when boiled, has its mucilage or coaguable part sepa-
rated in like manner, in the form of a pellicle, in proportion
as the evaporation takes place. And both milk and serum,
whether diluted, or not, agree in being coagulated by rennet
when exposed to heat (LV). So that milk seems to be made

1 See Newman's Chemistry, sect. ix.

(LV.) Dr. George Fordycea says that the serum may be 'coagulated by
a juice secreted in the stomach. Dr. Davyb found that serum is not
coagulated by calf s rennet ; and this observation is confirmed by the
following note with which he has favoured me : " I have repeated the
experiment with rennet, and with the same negative result, whether
using the weak brine in which the stomach of the calf was infused, or
a portion of the membrane itself ; whilst both coagulated milk, they
had no effect on serum, not even appearing to render it coagulable at
a lower temperature. The serum used was from the blood of the sheep.
If Hewson were deceived, as I am inclined to believe he was, it may
have been from his employing too high a temperature, and attributing
to rennet what was the effect of heat.'1 I have tried calf s rennet on
the serum of the horse, without producing any coagulation, at a tem-
perature gradually raised from 65°- 103°.

a Elements of the Practice of Physic, b Researches, Physiol. and Anat. ii, 97.
part i, p. 3, 8vo, Lond. 1770.

THE BLOOD. 81

of the mucilaginous part of the serum, or is a diluted serum,
with the addition of an expressed oil, or with a saccharine
substance instead of the neutral salts.

But although there is an analogy between milk and diluted
serum, in the circumstance of coagulation, yet they differ in
another, namely, diluted serum can by a moderate heat be in-
spissated without coagulating, or forming any pellicle on its
surface ; but if milk be exposed to the same heat, it is not in-
spissated so completely ; for a pellicle is formed on its surface
in proportion as the evaporation takes place, and this pellicle
seems to be as perfectly coagulated as if the milk had been
exposed to a boiling heat ; for it will not dissolve again merely
by adding water, as inspissated serum does.

Serum, therefore, by being diluted, comes near to milk in
the circumstance of its coagulation. But the coagulable lymph
cannot, by any art yet discovered, be made exactly to resemble
serum (LVI).

The mixture with neutral salts makes it indeed so far ap-

(LVI.) According to the views of M. Denis, a the liquid mixture of
coagulable lymph and a neutral salt is but serum with an excess of
fibrin, which he regards as identical with albumen, and ready to be
precipitated or coagulated under certain circumstances. See Notes
VTI, xu, xvi, and xvm. Schererb regards fibrin of arterial blood
as distinct from fibrin of venous blood, because he finds the first in-
soluble and the next soluble in a saline solution. He attributes the
difference to the action of oxygen, stating that fibrin is deposited from
its saline solution after exposure to the air ; and that the fibrin of ve-
nous blood, after having been some time exposed to the air, is no longer
soluble in a solution of salt. I have kept slices of the buffy coat of
venous blood, without any obvious alteration, except a little swelling, for
months in saturated solutions of nitre, common salt, and Glauber's
salt ; the specific gravity of the solutions always became rather di-
minished. As mentioned in Note vin, fibrin certainly undergoes mo-
difications in its chemical properties some time after its coagulation.
Miilder,c in support of Scherer's view as to the action of oxygen on
fibrin, says that the protein compound which, during the coagulation
of the blood, is changed into fibrin, absorbs oxygen in the lungs, and
circulates through the arteries in the state of a bi-oxyde and of a trit-
oxyde of protein ; and that both of them, besides being ordinary con-
stituents of blood, exist in it to an increased extent during inflammation,
and form the chief part of the buffy coat.

a Essaisur le Sang, pp. 81-4, 8vo, Paris, c Chem. of Vegetable and Animal Phys.

1838. tr. by Dr. Fromberg, pp. 307, 314,

b Dr. Turner's Elements of Chemistry, 316, 341, 8vo, part ii.

8vo, Lond. 7th ed. 1842, p. US8.

6

82 PROPERTIES OF

proach to the' nature of serum as not to be coagulated by
exposition to the air ; but it does not alter so considerably its
property of coagulating by heat, for the mixture with Glau-
ber's salts (in Experiment vn) coagulated at 125° ; and, I be-
lieve, would coagulate in a heat of 123°, if long exposed to it;
whilst the pure coagulable lymph is fixed between 114° and
12O|0 (see Note xvi), and the serum not under 160° of
Fahrenheit's thermometer (see Note xvn).

Of the white serum.

Although the serum of human blood be naturally transpa-
rent, and a little yellowish, yet it is frequently found to have
the appearance of whey, and sometimes to have white streaks
swimming on its surface like a cream, and now and then to be
as white as milk, whilst the coagulum is as red as usual. In
all these three cases of .whiteness I have examined it in a
microscope with a pretty large magnifier, and have found it to
contain a number of very small globules, although naturally,
when transparent, no globules can be observed in 'it, notwith-
standing what has been affirmed by some authors. These glo-
bules differ from the red particles (improperly called globules)
in their size, which is much smaller ; and likewise in their
shape, which is spherical, whilst the red particles are flat.
They agree more with the globules of milk, I have compared
them with those of woman's milk, and have found that in the
milk the globules are of different sizes, some being three or
four times as large as others, and the smallest little more than
just visible, when viewed with a lens of one-twenty-third of an
inch focus, whilst those of the white serum are more regular,
and are all of them about the size of the smallest globules of
milk (LVII). Of this white serum I have met with the following

(LVII.) This is an accurate account of the microscopical characters
of the milky matter. A few granules, about ^oVo of an inch in dia-
meter, are commonly mixed with it ; but its bulk is made up of particles
scarcely -5^075^ °^ an incn in diameter, and agreeing in all respects
with those which compose the molecular base of the chyle, a and give
to it the white colour. These are not to be confounded with the chyle-
globules, of which the average diameter is about -^VTJ of an inch.b

a Appendix to Gerber's Anat. pp. 21,98, b See the Tables of Measurements,
figs. 274-8 ; and Dr. Willis's tr. of Wagner's Note cxviii*.

Physiol. i, 247, fig. cxlix.

THE BLOOD. 83

instances in books: in Tulpius one instance;1 in Morgagni
two;2 in the Philosophical Transactions some instances;3 in
Skenckius's Observations two cases are related from other
authors.4 I have likewise heard of the same appearance hav-
ing been observed by the learned Sir John Pringle, Dr. Pit-
cairn, Dr. Hunter, Dr. Watson, Dr. Bromfield, Dr. Gartshore,
and Dr. Fothergil of Northampton. And other instances have
lately occurred to persons of my acquaintance, who have
favoured me with a short account of them.

Mr. French, apothecary in St. Alban street, having informed
me that he had some blood by him, taken from a woman the
day before, whose serum was as white as milk, he favoured me
with a small quantity of it for examination, and with it the fol-
lowing particulars of the case : " Mary Rider, about twenty-
five years of age, of a fresh complexion, and lusty, has not had
her menses for these seven months. She discharges blood some-
times by vomiting and sometimes by stool ; complains of a pain
in her left side and in her stomach ; she has an inclination to
eat, but when she tries, she soon after loathes her food. She
complains of great lassitude and sleepiness ; her pulse is ninety-
five in a minute. She has been bled twelve times within these
six months, and every time the serum was as white as milk."

Mr. Robertson, apothecary in Earl street, acquainted me,
that " Mr. Herbert, a publican, of about thirty-five years of
age, and corpulent, had been subject to a bleeding at the nose,
to the piles, and to such profuse sweats in the night, as to be
frequently obliged to change his shirt in the morning before he
got out of bed, but that, for some time past, his sweats had
ceased. That, on September the 23d, he was seized with a
bleeding at his nose, which had been preceded by a pain in
his head for two or three days. That his bleeding continued
till he had lost about two pounds of blood, and then stopped ;
and that the serum of his blood was as white as milk. That
at ten o'clock .the same night, the hemorrhage returned, and
he lost a considerable quantity ; nevertheless, it was thought
proper to take sixteen ounces of blood from his arm, during
which evacuation he fainted, but his bleeding at the nose
stopped. That the serum of this last blood was likewise very

1 Tulp. Ob. 1. i, cap. 58. 3 Philosoph. Transact. Nos. 100, 442.

2 Morgagni, Ep. xlix, art. 22. * Sckenckij Obs. lib. iii.

84 PROPERTIES OF

white. That on the 25th, in the morning, he again complained
of a pain in his head, and about ten o'clock his nose began to
bleed again ; but the serum now appeared no whiter than whey.
That he continued to lose blood during most part of the night,
so that it was supposed he could not lose less than two or three
pounds, the serum all this time being a little whitish, but so
little, that the bottom of the vessel in which it stood could now
be seen through it. That his bleeding returned repeatedly till
the 3d of October, when it entirely stopped, the serum having
become more transparent towards the last."

Mr. Eustace, apothecary in Jermyn street,, sent me a phial
of white serum from one of his patients, by trade a butcher.
" This man," he told me, " was tall, of a strong make, a hard
drinker, subject to puke every morning, took little food,
sweated a good deal, but did not waste in his flesh. He was
bled for a slight asthma to which he was subject, and of which
he had always been relieved by bleeding. In other respects
he was in a good state of health, so as to follow his business
without much inconvenience."

Besides these cases, my friend Mr. Lambert, surgeon at
Newcastle-upon-Tyne, told me, " that he had a patient some
years ago with a violent rheumatic pain in his hip, whom he
was obliged to bleed thrice, and every time his serum was as
white as milk, but the coagulum of its natural colour. This
gentleman," Mr. Lambert adds, " was a free liver, of a full
make, but rather muscular than corpulent, and remarkable for
being a great walker."

When I first saw this unusual colour of the serum, I was
inclined to adopt the opinion of those who have attempted to
explain it by the patient's being bled soon after a meal, or be-
fore the chyle was converted into blood. But afterwards, on
considering the cases above related, I found this could by no
means be the cause, as none of these patients had taken a suf-
ficient quantity of food to occasion this appearance; on the
contrary, most of them had a bad appetite, and had taken re-
markably little food, and were subject to vomitings. I there-
fore concluded it was owing to something else, and what con-
firmed me in this opinion was an observation I had repeatedly
made in dissecting geese, whose serum I had frequently seen
white, whilst their chyle was transparent ; although they had

THE BLOOD. 85

been killed only three or four hours after eating. And as the
whiteness, in all the cases that I examined, was owing to a
quantity of small globules like those of milk (which are known
to be oily) I concluded that these in the human serum, when
white, were oily likewise, and recollecting to have read some-
where of an experiment by which butter had been got from
such human serum, I tried, by agitating some of it a little di-
luted, to separate its oil, or to churn it, but without success. I
then inspissated some of it to dryness, and compared it with
the natural serum of human blood prepared in the same way,
and found it "less tenacious, and much more inflammable ;
and when thus dried, its oil oozed out so much as to make the
paper in which it was kept greasy (LVIII). Another portion

(LVIIT.) Mr. Hunter* observed that the milky serum is not the same
in all cases, as the globules which form the wheyish appearance some-
times swim and sometimes sink in water ; and he believed that the super-
natant milky matter does not exist in the circulating blood, but is formed
after the separation of the serum. Hewson's proof, that the milk-like
matter is of a fatty nature, has been confirmed by Dr. Traill,b
Dr. Christison,c Dr. Benjamin Babington,d and Heller.6 I have several
times seen the milk-like matter on the surface of the blood, both
arterial and venous, before there was any separation of serum and
before coagulation was complete.

The milky appearance on the blood or in the serum was ascribed by
Boyle and *Lowerf, Gibson,^ St. Hilaire,h Lister,1 Dr. Arbuthnot,J
Quesnay,k Stuart,1 Senac,™ William Fordyce,n and Rush,0 to an admix-
ture of chyle with the blood. This opinion has been confirmed by the
experiments of Hutchinson,p whose dissertation I have not seen, by
Mr. Thackrah,q Dr. Buchanan/ and myself.8 But there is a turbid
and whitish serum neither owing to the presence of chyle, nor to
oily matter ; and probably connected with disease, as indeed a fatty
serum sometimes is. In one specimen of serum resembling thin water-

a Works, ed. by Palmer, iii, 55-6. k Principes de Chirurgie, 8vo,Paris,1746,
b Edin. Med. and Surg. Journal, xvii, p. 34.

235, 637; and xix, 319. • Phil. Trans. 1735-6, xxxix, 289.

c Ibid, xxxii, 286. m Traite du Comr, torn, ii, p. 77, ed.
d Med. Chir. Trans, xvi, 47-50. 1749.

e Dr. Simon's Animal Chemistry, tr. for n Inquiry into the Causes of Putrid and

Syd. Soc. p. 271, 8vo, Lond. 1845. Inflammatory Fevers, 8vo, Lond.

f Phil. Trans. 1665-6, i, 117. 1773, p. 24.

s Anat. of Human Bodies Epitomized, ° Med. andPhys. Journ. 1806, xvi, 199.

p. 276, 3d ed. 8vo, Lond. 1688. p Inaug. Dissert, on the Conversion of
h Anatomic du Corps Humain, torn, ii, Chyle into Blood, 1804.

p. 124, 8vo, Paris, 1698. « On the Blood, ed. 1834, p. 130, Exp.
1 Dissertatio de Humoribus, 8vo, Lond. CLXVII.

1707, p. 236. r Trans. Glasgow Phil. Soc. March 1844.

J Essay concerning Aliments, p. 33, 8vo, • Appendix to Gerber's Anatomy, pp.

Lond. 1731. 21-2,90.

86 PROPERTIES OF

of this white serum being kept some days, putrefied, and when
putrid, it jellied as milk does when become sour ; but it dif-
fered from milk, in being extremely fetid.

Now, as the white globules appear from these experiments
to be of an oily nature, and as it is improbable, from these pa-
tients having taken little food, and from the transparency of
the chyle in birds, that this whiteness of the serum should be
owing to unassimilated chyle, accumulated in the blood-vessels ;
we must therefore believe it to be owing to some other cause.
And as we know there is a considerable quantity of oil laid up
in the cellular substance of animals, which is occasionally re-
absorbed is it not most probable that this curious appearance
was, in the above-mentioned cases, owing to such a reabsorp-
tion ? And as all these patients had symptoms of a plethora,

gruel, Dr. Traill could detect no oil. Dr. Bostock1 obtained similar
negative results from an examination of turbid and cream-like serum in
cases of dropsy with albuminous urine ; it was in this disease that Dr.
Christison referred the cloudiness of the serum to the presence of
oily matter. Dr. R. D. Thomson found the white matter oily in one
of Dr. Buchanan's cases, and in another not so. In a case of anasarca,
Mr. Ancellu observed the serum in the highest degree turbid, but not
milky. I have seen three specimens of turbid whitish serum in the
human subject, in which the opake matter sunk in water, was not at all
soluble in ether, and appeared irregularly granular under the micro-
scope, resembling coagulated albumen, but quite unlike chylous or
fatty matter.

In Dr. Benjamin Babington's observations/ the specific gravity (see
Note xxn) of the milk-like serum appeared to be so regularly reduced,
as to lead him to believe that the oil exists at the expense of the albumen.
There are some facts in favour of the idea that albumen may be converted
into oil. The rapid disappearance of the matter of the curd of perfectly
fresh salmon, with the subsequent more oily state of this fish, may be
owing to a conversion of this kind, according to the conjecture of Sir
Humphrey Davy, as I have learnt from Dr. Davy. I have observed that
the oil in the liver of several fishes increases after death, probably in
connexion with incipient putrefaction ; and Dr. Davy informs me that in
the liver of the cod, after it had been kept in a damp place for twenty-
five days, he found a small increase of oil, with a formation of ammonia
and carbonic acid at the same time. Perhaps, as Dr. Babington suggests
to me, there may be a conversion of vegetable albumen into oil, in olives,
after they have been heaped up and subjected to fermentation ; by which
the quantity of oil is said to be increased, though its quality is not so good.

I Dr. Bright's Reports of Med. Cases, v Cyclopaedia of Anat. and Physiol. i,

4to, i, 83. 423.

II Lectures on the Blood, Lancet, vol. i,

1839-40, p. 607.

THE BLOOD. 87

and were relieved either by spontaneous hemorrhages, or by
bloodletting, is it not probable that, to whatever purpose (see
Note LX), the oil is applied in the body after it is reabsorbed
from the cellular membrane, in these patients it had been re-
absorbed faster than it was applied, and by that means was
accumulated in their blood-vessels ? This conjecture seems to
be confirmed, from considering that in most of these cases the
people were inclined to corpulency, and that two of them
laboured under a stoppage of a natural evacuation.1

Another conclusion which these observations lead us to is,
that since the chyle of the birds (LIX) which I dissected was
not white, but transparent, at whatever time after eating it was
examined, it follows, that the fat (in these animals at least) is
not merely the oily part of the chyle or of the food, but is a
new substance, or a new combination of the principles or ele-
ments, which is made probably in the secretory organs of the
adipose membrane ; the form of oil being made use of by na-
ture in preference to any other for the nutritious substance of
the body, from its being the least liable to putrefaction, and
from its containing the greatest quantity of nourishment in the
least bulk. This circumstance was clearly proved by my valu-
able and ingenious friend the late Dr. Stark (LX), who, in a

1 Although it appears probable that the whiteness of the serum in the above-
mentioned cases was not owing to the chyle, yet I would not conclude that the chyle
does not in the human subject occasionally colour the serum. We frequently observe
the serum of such people as are bled a few hours after a meal, a little turbid, like
whey, which I believe may be owing to the chyle. But if the milk-like serum was
occasioned by a full meal, it is likely we should oftener see it than we do.

(LIX.) The chyme of birds differs very little from that of mammalia.
In geese fed exclusively on barley, in many wild finches, and in pigeons fed
on nothing but peas, I found a much greater proportion of fatty matter
in the chyme than in the food. An observation, communicated to me
by Dr. Davy, is still more conclusive : in the chyme of a pheasant he
found oily matter, which he could not detect in the food, consisting of
pilewort, in its crop. The subject is interesting in connexion with the
contending views of Liebig, Boussingault, and Dumas, a on the question
of the formation of fat in animals. The chyle of birds, as Dr. Davy
suggests to me, may perhaps enter the circulation by the veins rather
than by the colourless lymphatics.

(LX.) Dr. William Stark' s works, consisting of clinical and anatomical

* Mr. Paget's Reports, Br. & For. Med. Rev. xvii, 260 ; xix, 564.

88 PROPERTIES OF

course of curious experiments, made by weighing himself after
living for some time on different sorts of food, discovered that
a less quantity of suet was sufficient to make up for the waste
of his body, than of any other sort of ordinary food ; and that
when compared with the lean part of the meat, its nutritive
power was, at least, as three to one.

I may here add another circumstance that occurred to me
when I first thought on this subject, which is, that since we
believe the oil, or animal fat, is reabsorbed from the adipose
membrane to serve for nourishment to the body ; and as some
of the patients (whose cases have been related above) could not
take food, the reabsorption therefore of this oil might not be
so much the cause, as the effects of the disorder under which
they then laboured ; or, in other words, that upon some de-
fect in the digestive organs, the powers of nature drew from
their magazines of oil in the adipose membrane a supply of

observations, with experiments dietetical and statical, were revised and
published from his original MSS. by Dr. James Carmichael Smith, 4to,
Lond. 1788. Dr. Stark died in 1770, seemingly from the effects of his
experiments ; he was encouraged in them by Dr. Franklin and by
Sir John Pringle.

Liebig considers fat as chiefly useful, by its slow combustion during
respiration, in maintaining animal heat. Nearly two centuries ago, an
opinion was current, and opposed by Needhama that the body is kept
warm by an internal combustion of the blood, chiefly in the lungs.
Fatty matter, I believe,b is intimately concerned in growth and nutrition,
healthy and diseased. The base of the chyle, referred to in Note LVII,
is made up of minute and equal-sized fatty or oily particles ; the mole-
cules or seeds of cells, so abundant in the semen of oviparous vertebrate
animals, just before the breeding season,0 are composed chiefly of fatty
matter ; and such also is more or less the nature of elementary granules
generally, and of the nucleoli of cells. The analyses of Dr. Davy
support my observations as to the fatty nature of the molecules of cells
in disease/ Mr. George Rosse is of opinion that the general lymphatic
system converts oily matter into a compound of protein ; and he states
that Dr. Carpenter included in this idea the whole supposed waste
reorganizable matter of the system.

a De Formato Fcetu, cap. vi, 12mo, Lond. d Notes appended to Dr. Boyd's Vital

1667. Statistics, in Edin. Med. and Surg.

b Med. Chirurg. Trans, xxvi, 93-6; Journ.lx, 159 et seq. Henle, Anat.

London Med. Gaz. June 21, 1844, Gen.tr. par Jourdan, p. 126; Ascher-

p. 411. son, Mr. Paget's Report, Br. and

0 Proceed, of Zoological Society, 1842, For. Med. Rev. xiv, 263.

pp. 99 et seq. e Lancet, 1843-4, i, 629.

THE BLOOD. 89

that fluid then perhaps necessary for the use of the body. In
order to clear up this point, I thought it would be a satisfactory
experiment to compare the serum of the blood of animals at
different periods after feeding them. For if the reabsorption
of the oil was merely to make up for the want of other food,
or if the serum was white merely from a greater quantity of
oil being taken up in order to supply the wants of the body,
then the serum ought to be whitest in the animal kept longest
without food, or whose body was most in want. And as I had
found that geese had very commonly this white serum, though
their chyle was transparent, I chose to make the experiment on
them. I therefore took two of them that were very hungry,
and feeding both of them with oats, one I killed four hours
after, when I knew a part of the oats were undigested ; and
upon examining the blood, I found the serum whitish, and full
of small globules ; on its being suffered to stand a little time,
the white part ascended to the surface like a cream. The
other was killed forty-eight hours after eating, when its stomach
was found empty, • and the serum of its blood quite trans-
parent, and without any cream rising to the surface, or any ap-
pearance of small globules, when examined with the microscope.
Now this experiment seemed to me decisive, and to point out
clearly that the whiteness of the serum was not occasioned
merely by the body being in want of food, and therefore draw-
ing the oil from its magazines ; because here the animal most
in want of food had its serum least white ; but was occasioned
by the fat being reabsorbed faster than it was used (from its
place being supplied by the fresh chyle) and thence was accu-
mulated in the blood-vessels, so as to give whiteness to the
serum. And from the same observation it likewise appears
probable, that the great reabsorption, and the accumulation
of the fat in the vessels of the plethoric patients above men-
tioned, was the cause of their want of appetite, and of their
other complaints, and not the effect of them.

May not therefore a too great reabsorption of the fat, and
its accumulation in the blood-vessels, be now admitted as the
cause of one species of a plethora ?

And may it not likewise be useful in some complaints of the
stomach to attend to the whiteness of the serum ? For although

90 PROPERTIES OF THE BLOOD.

fat be a substance little liable to disease, yet it may perhaps be
sometimes so vitiated, or may so incommode nature, that she may
be obliged to take it up from her magazines, and to use it, or to
throw it out of the body. Whilst this is doing, a sickness of
the stomach and want'of appetite may be indications of fulness ;
and therefore, instead of wanting remedies to strengthen the
stomach, may require bleeding and other evacuations.

APPENDIX,

RELATING TO

THE DISCOVERY OF THE LYMPHATIC SYSTEM IN BIRDS,
FISH, AND THE ANIMALS CALLED AMPHIBIOUS;

BEING

A VINDICATION OF THE AUTHOR*S RIGHT TO THESE DISCOVERIES, IN OPPO-
SITION TO THE CLAIM OF DR. ALEXANDER MONRO, PROFESSOR
OF ANATOMY IN THE UNIVERSITY OF EDINBURGH.

AN account of the lymphatic system in birds, fish, and a
turtle, was given to the public in the Philosophical Transac-
tions, vols. Iviii and lix, for which communications the Royal
Society has since honoured me with their gold medal. These
discoveries Professor Monro claimed, in a letter read before
that most respectable body on the 19th of January, 1769, and
has since persisted in that claim, in a pamphlet called ' A State
of Facts/ &c., printed at Edinburgh, 1770. Now as both
that letter and the pamphlet must of course have been seen by
many who know not what can be urged against them, I think
it but a duty I owe my own character to lay before the public
the proofs I have collected of their insufficiency to procure
Professor" Monro the credit of having anticipated me in those
discoveries ; and I hope that, although in doing this I shall
trespass on the time and patience of the reader, yet it will be
some excuse for me that I had endeavoured, as much as could
be expected on my part, to settle the dispute without troubling
the public with it.

As Professor Monro has, in this pamphlet, not only endea-
voured to vindicate his claim to these discoveries, but has like-
wise censured me on account of a paper on the emphysema,
it is necessary, before I come to the controversy about the
lymphatics, that I should relate what has passed between us on
that occasion.

In the third volume of the ' Medical Observations and In-

92 APPENDIX.

quiries' is published a paper on the emphysema, in which I
proposed the operation of the paracentesis of the thorax, to
let air out of the cavity of the chest, which air I endeavoured
to show was the cause of the worst symptoms attending that
disease. Not long after this, I was informed that Dr. Monro
had declared publicly he had mentioned that observation in
his lectures, both at the time and before I attended them,
which was in the winter 1761, and complained that I had
omitted doing him justice in this particular.

When I heard this I made inquiries of some of his pupils,
who I found had taken notes at his lectures, and by two of
these gentlemen I was favored with excerpts from their notes,
which convinced me that he had anticipated me in proposing
that improvement. I then determined to let him know that
my omitting to mention his name on that occasion was en-
tirely owing to my ignorance of his claim. This I was the
more desirous of doing, from having heard that he had ex-
claimed against me with some acrimony, on the supposition
that I had got the hint from him, and was conscious of it,
which being far from the truth, I determined to show him in
what manner I had really made the observation, and thereby
stop his exclamations. I determined likewise to show him that
I was desirous of giving him the credit of having had the idea
before me, and thereby to prevent all dispute about the matter.
The following is a copy of the letter which I sent him on that
occasion :

" Sir, — Being informed that you have publicly complained
of me ' for having, in a paper printed in the third volume of
the Medical Observations and Inquiries, omitted doing you the
justice of mentioning your having proposed the operation there
recommended, in the same circumstances, long before -,' and as
I am confident I deserved not to be complained of on that ac-
count, I have taken this opportunity of stating the manner of
my making the observation, and at the same time of letting
you know that since I have learned that you likewise had
made it, I am willing to do you justice. The thought first
occurred to me in reading Mr. Cheston's Pathological Inqui-
ries and Observations, in which he gives a case of the emphy-
sema; this case is told in such a manner that I think it is
hardly possible any unprejudiced person should read it and not

APPENDIX. 93

be convinced, as I was, that the cause of the principal symp-
toms was air in the cavity of the chest. Mr. Cheston himself,
in relating that case, came as near making the observation as
possible.1 From this hint I prosecuted the subject, as is men-
tioned in that paper ; and before I published it, I consulted
every author I could easily procure, who I thought was likely
to treat of the subject. And I certainly should have done
justice to any that I found had anticipated me, and should not
have avoided the opportunity of doing you the same justice.
But I knew not, at the time of that publication, that you had
ever given the least hint on that subject. About the middle
of last summer I was told by a gentleman from Edinburgh of
your manner of treating me, at which I was not a little sur-
prised,- as I was not conscious of having given you the least
cause of complaint. But having since learned, from other
gentlemen who attended your lectures before the time of my
publishing that paper (and who, at my request, consulted their
notes) that you had really mentioned it, I cannot now doubt
that you had made the observation before me. At the same
time I must assure you, that to suppose I knew it at the time
of publishing that paper was doing me injustice. Your accusa-
tion, I presume, is founded on the supposition of my having
heard you deliver the observation at your lectures, when I had
the pleasure of attending them. But I do assure you, that if
I ever heard the least hint on that subject, either from you or
from any other person, I had not any remembrance of it at
the time I wrote that paper. You are not, indeed, the only
person who, as I now find, has anticipated me : the author of
the Monthly Review for last June2 says he had long had the
same idea, and that he mentioned it in his account of Mr.
Cheston' s book. But of this too I assure you I was ignorant
when I wrote my paper. What must give farther conviction
to any unprejudiced person of my ignorance of your having
made the observation is this — I first mentioned it in a paper

1 I have since been informed by Mr. Cheston that I misunderstood his meaning^
when I concluded that he explained the worst symptoms of the emphysema on dif_
ferent principles from what I have done, and that he meant to attribute them to air
in the chest, and, therefore, that the observation was sufficiently made out in his
paper ; which see in his ' Pathological Inquiries and Observations,' pp. 7, 8.

2 See Monthly Review for June, 1768, p. 446.

94 APPENDIX.

which I read to a private society, in which were present many
gentlemen that had attended your lectures, and yet all these
gentlemen expressed themselves pleased with the observation,
as new and interesting, and not one of them gave the least
intimation of their having ever heard it before. And yet those
gentlemen are as likely to remember any observation which
tends to the improvement of physic or surgery as any I know.
I shall mention their names, to justify my good opinion of
them — Drs. Stark, Parsons,1 Saunders,3 Pepys,3 and Ruston.4
The observation was likewise mentioned in another society of
young gentlemen, and also in a public hospital, where many who
had been your pupils heard it ; and yet no person ever told me
before I published that paper (which was almost a twelvemonth
after I had first mentioned the subject) that you or any other
person had ever anticipated me. However, this I relate only
to show I was ignorant at that time of your having made the
observation. But now I know that you had, I have not the
least unwillingness to acknowledge it, and to do you justice in
any future publication. At the same time that I justify my
own conduct, give me leave to say that your manner of treat-
ing me (if fairly represented) was not so civil as might have
been hoped for. When you complained of me, 'tis a pity you
had not likewise hinted there was a possibility of my being
ignorant of your having had the idea. You might perhaps
too, without impropriety, have hinted that should it come to
my ears that you had anticipated me, I might possibly be
capable of such an exertion of candour as to acknowledge it.
But, to have done with suppositions, this at least I am sure of,
that though I may be as covetous of fame as most people, yet
I am incapable of taking any unjustifiable methods of ac-
quiring it. "I am, Sir, &c.

" Dec. 31, 1768."

This letter, Professor Monro could not but acknowledge,
" sufficiently satisfied him in having secured his title, as the

1 Professor of Anatomy at Christ's Church, Oxford.

2 Physician to Guy's Hospital.

3 Physician to the Middlesex Hospital.

4 Some of these gentlemen attended Dr. Monro's lectures about the same time
with myself, the others since.

APPENDIX. 95

first who had proposed that improvement." Yet so unfair an
account does he give of it in his f State of Facts/ that he only
says I acknowledged that " I could not doubt he had made the
observation before; but the farther particulars of it (he adds) it
is needless to trouble the reader with, since as much as is neces-
sary of these will be sufficiently understood from his letter" in
answer to me, which surely is not the case ; for it nowhere ap-
pears in his letter that, besides mentioning my conviction of his
having anticipated me, I had likewise promised to do him justice
in a future publication. Nor does it appear in his letter that I
had in mine shown how little probability there was of my having
got the idea from him. These the reader may perhaps think
Professor Monro ought to have declared, in justice to me. For
what more could be expected of me, seeing I had by accident
hit upon an observation which, as it happened, he had made
before, than to acknowledge the priority of his title as soon as
I knew it, and to put that letter into his hands by which he
might always be sure of securing to hfmself what was his due.
But Professor Monro says it was unnecessary to give a fuller
account of my letter. But why was it so ? Not surely in
justice to me, nor for the satisfaction of the reader. Nay, so
far is Dr. Monro from doing me justice on this occasion, that
he even intimates I rejected tapping the chest with a trocar,
because it happened to be his method, as if the same was not
the method recommended by many of the writers on the sub-
ject of the paracentesis of the thorax, for the cases in which
they advise that operation, to whose method I alluded, and not
to his, which I then knew nothing about.

Next, as to the discovery of the lacteals and lymphatics in
birds, fish, and the animals called amphibious ; of these an ac-
count was laid before the Royal Society on December the 8th,
1768. I was present when it was read, and had afterwards
some conversation on the subject with Dr. Donald Monro, who,
as appears by the sequel; informed his brother, the Professor,
of what I had done. Not long after this, I again saw Dr.
Donald at St. George's Hospital, and he then told me, that
the lymphatics and lacteals in those animals1 had been dis-
covered by his brother eight years ago, as he now learnt by a

1 Meaning birds and fish.

96 APPENDIX.

letter from Edinburgh, a part of which letter he was to show
to every body, and which was already given to be read before
the Royal Society. When I was informed of this, I was
astonished, as I remembered to have heard the Professor, since
that time, declare that they were not discovered. Besides, I
had a note taken from his lectures within two years of his
making this claim, in which was a similar acknowledgment.1 I
was convinced therefore that he had no title to these discoveries.
Upon which I laid before the Royal Society my reasons for that
conviction, in a letter to one of their secretaries. Of this letter
I shall give the reader an account, but shall first lay before him
a literal copy of Dr. Monro's claim.

Copy of Dr. Alexander Monro's claim, fyc. read before the
Royal Society, Jan. 19, 1769.

" Above four years ago (says he) I injected the lacteal vessels
of a turtle, or sea-tortoise, with quicksilver, after injecting the
artery and vein with wax, and have shown this instance of the
vessels in the oviparous animals every year in my college, and
had a drawing made of it two years ago by Dr. Palmer, a copy
of which I have sent inclosed, engraved by Donaldson.

" I likewise, eight years ago, mentioned those vessels in
fowls and fishes, which I had seen, but not injected."

Here then is an assertion about the vessels which I had dis-
covered, that is far from being equivocal. For here he affirms,
that he really had seen them eight years ago, nay, that he had
even mentioned them to others. This letter too was sent im-
mediately after he heard that I had laid before the society an
account of those vessels in birds and fish.2 It could not there-
fore be meant merely to inform the society that, now seeing
Mr. H. had discovered the lacteals and lymphatics in birds and
fish, he likewise had the pleasure of shewing them that he (Dr.
Monro) had discovered them in the turtle. This, I say, could
not be his meaning ; for if it was, why did he send his letter
so precipitately ? Why did he not send a description of those
vessels in the turtle, in order to make his letter worthy of their
notice ? And why did he say he had seen them in birds and

; That note is now printed below, p. 98.
2 As he acknowledges, ' State of Facts,' p. 4.

APPENDIX. 97

fish ? The society, he knew, wanted not his testimony to prove
that birds and fish had them. What, then, could he mean by
it, but to claim the discovery ?

As there could be no doubt that Professor Monro meant
this letter as a claim to these discoveries, neither had I any
doubt but I should, for the reasons above mentioned, prove that
he had no right to them. In order therefore to prevent the
prejudices that might arise against my papers, from his being
believed to have anticipated me in these discoveries, I wrote a
letter to one of the secretaries of the Royal Society, in which
I first showed that I had seen the lacteals of the turtle about
a year before Dr. Monro, and then, when I came to speak of
those vessels in birds and fish against the probability of Dr.
Monro's having anticipated me in these discoveries, I made use
of the following arguments :

1st. His not having, by his own confession,1 injected them,
which he certainly would have done in order to complete the
discovery. To which I observed he had the strongest motive,
both from his knowing the importance of the subject, and
from his having unfortunately declared, in the 57th page of
his 'Anatomical and Physiological Observations/ printed at
Edinburgh, 1758, "that, after a considerable number of experi-
ments which he had made, he was convinced that neither birds,
fishes, nor oviparous animals in general, had either lacteals or
lymphatic vessels." After which declaration I conceived it im-
probable he should patiently wait eight years without injecting
them, especially as I had found it an easy matter to inject
them, when once they were discovered ; and, I added, the pro-
bability was that if he had seen those vessels, he would have
hastened to inject them, and to complete the discovery, were it
only to prevent another person's doing it, and thereby acquiring
the reputation of having done what he himself had in vain at-
tempted by such a considerable number of experiments as were
sufficient to convince him that such vessels existed not in those
animals.

2dly. I said his claim to the discovery of those vessels, by
affirming he had seen them eight years ago, was contradicted
by public declararions made after that time ; for he had since
acknowledged in his lectures, that he had sought for them in

1 In his claim ; see above, p. 96.

7

98 APPENDIX,

vain by a variety of experiments. And even so late as within
these two years,1 he declared likewise in his public lectures,
"that the lymphatic system was supposed to take place only
in men and viviparous animals, and by analogy in those fishes
placed by Linnaeus amongst the mammalia, and how far was
their just extent (he said) was not certain, but that he had
found them in some amphibious animals, as in the turtle/'
These declarations, I observed, were inconsistent with his claim
to the discovery.

Besides using these arguments, I promised the Society I
would hereafter produce unquestionable proofs of the invalidity
of his claim, having by this time found that the Doctor, fortu-
nately for me, had expressly acknowledged in his lectures, that
he had sought for them in vain, almost every year since the
time that he now pretends to have seen them.

Dr. Monro being informed of these proceedings, sent me his
letter, dated June the 8th, which he has since printed in his
< State of Facts/ But that letter appeared so confused, that
I knew not what to make of it. Sometimes I thought it was
meant to prove that he had discovered those vessels, agreeably
to his assertion read before the Royal Society: but this I soon
after suspected could not be the case; because, after relating
all his facts and experiments, he concludes, not that he had
discovered them, but only " that he had seen what he strongly
suspected to be lacteals in those animals " (viz. birds.2) — And,
" that (from preceding experiments) he was persuaded that birds
were provided with lacteal vessels, and confirmed in this opinion
by having injected them in one of the same oviparous class, the
turtle;"3 or, in other words, Dr. Monro claimed a discovery
by telling the Royal Society that he had seen those vessels in
birds eight years ago, which he now proves by showing he had
only suspicions about them, and an opinion that birds had
them because turtles had them.

At other times I thought that possibly, after finding what
his pupils testified, he might now be convinced he had impru-
dently claimed those discoveries, and might intend this as a
sort of an acknowledgment (though an awkward one) of my
being the first who had seen those vessels. But the vindictive

1 My letter being dated Jan. 10, 1769. * State of Facts, p. 21. * Ibid. p. 23.

APPENDIX. 99

style of his letter convinced me it was not meant as an apology,1
as likewise did the style of a short note written on the cover
of that letter, of which note the following is a copy.

To Mr. Hewson, fyc.

SIR, — When you have read the inclosed, you are very wel-
come to write such remarks on it as to you, or to your friend

Dr. H — r, or to any of his friends, such as Dr. , &c. may

seem proper; only when you have done, I think you ought to
show it to all those societies, physicians, and students to whom
you have made free with my name ; or, if this talk should not
suit your disposition, or be irksome to you, after the great
fatigue you have taken about me already, please to let me know
this, and I shall take that trouble on myself. I am, sir, &c.

(Signed) ALEX. MONRO.

Edinburgh, June 24, 1769.

This seemed clearly not to be the style of one who was sen-
sible of his error, and was apologizing for it ; and convinced
me that Professor Monro intended that letter as a proof of his
right to those discoveries. However, not to be positive that I
had hit upon his meaning, I determined, before I laid anything
before the public, to ask an explanation of that letter. For
this purpose I wrote to him on the 15th of July, and desired
him to tell me " whether he meant it as a proof of his right to
those discoveries ;" or, " whether he meant by it to give up to
me the right to them." And as I had found him in that letter
wandering from the subject, and instead of concluding that he
really had seen those vessels, concluding only that he had seen
what he suspected to be the lacteals in birds. And again, that
lie was persuaded birds were provided with those vessels, but
nowhere saying that he had seen what he knew or could prove
to be their lacteals, which alone could give him a right to the
discovery • I therefore told him " that, to avoid for the future
all wandering from the subject, I should state the dispute as
it appeared to me;" and then I said that "it was he who
began it, for, on hearing that I had discovered the lymphatic

1 As for instance where he talks " of (his)- making all the allowance I require for
my natural, or," says he, " I should rather call it, unnatural imbecility of memory."
This passage is altered in his ' State of Facts,' p. 22.

100 APPENDIX.

system in the three classes of oviparous animals, he had sent a
letter, which was read before the Royal Society, and was to be
shown to everybody. In this letter he asserted that he had
discovered the lacteals in a turtle about four years ago, and
in birds and fishes eight years ago, and that he even mentioned
these discoveries to others." These assertions (I added) were
construed a claim to the discoveries I had made. With this letter
I likewise sent him a copy of mine, which had been read before
the Royal Society. By these means I thought I should either
keep him to the subject in question, or, if he should again wander,
the reader would be convinced it was not my fault, but his own,
that he now knew not what he had then asserted.

This letter, however, had no effect. I therefore wrote to
him again, hoping he might now be convinced that his claim
was ill-founded, and might therefore be induced to retract it,
instead of obliging me to prove to the world its invalidity.
The following is a copy of the letter which I sent him on that
occasion :

SIR, — It is now above six weeks since I wrote to you, de-
siring an explanation of your letter of the 8th of June. As
you have not given me that explanation, I have now taken up
the pen to inform you, that agreeably to your own desire, and
in order to justify my conduct towards you, I am commenting
upon that letter which you sent me. My comment would be
more to the purpose, were I always sure I understood you, but
if that satisfaction should still be denied me, I must proceed
as well as I can, and I must say, that if I should mistake your
meaning, it will not be wilfully, since you might, by an
answer, have cleared up all ambiguity. I cannot help regret-
ting that this dispute should subsist between us, both on my
own account, as I think it hard to have the trouble of proving
my right to discoveries which are certainly my own, par-
ticularly as it takes up that time which I hoped to employ to
a better purpose ; and I likewise regret it on yours, since, in
order to maintain my right, I shall be under the necessity of
producing some facts and testimonies, which, in my opinion,
cannot but lead to conclusions very unfavorable to your repu-
tation. And as I should be sorry that one of my first at-
tempts to lay the foundation of my own character, should be
attended with circumstances which may hurt yours, and really

APPENDIX. 101

wish to avoid it ; I therefore still hope that this dispute may
be settled in a more easy manner. You must, I think, be now
convinced, that in claiming these discoveries you have injured
me, and cannot be at a loss to know what might be expected
from you on such an occasion. But if instead of doing me
that justice which might be expected from a man of candour,
you treat this letter likewise with silence, then justice to my-
self requires that I should no longer delay producing such
proofs as I possess of your having no right to these discoveries,
and showing them to the very respectable Society to which I
have promised them ; or to such physicians, surgeons, &c. as
may have heard of your claim ; without regretting much that
those measures which I take to maintain my right, may per-
haps affect sensibly the character of a man, who having first
injured me and afterwards had his error pointed out to him,
was incapable of candidly acknowledging it. — I am, sir, &c.

(Dated) Sept. 9, 1769.

In answer to this letter, he sent me one dated September
30, in which, instead of answering my questions, he evades
them, concludes as vaguely as in his former; and when he
speaks of his assertions read before the Royal Society, alters
its sense, qualifying the alteration with " to the best of his re-
collection," denies he was mistaken in claiming these dis-
coveries, and what is still more remarkable, accuses me of
having made conclusions injurious to him, "by arguments,
weak, inconclusive, not real, but feigned ."

It was evident, from such a letter, that he would not embrace
the opportunity I offered him, and avoid a dispute, by ac-
knowledging his mistake, and retracting his claim. I there-
fore no longer hesitated to print the proofs I had collected of
his not having anticipated me ; and though I had once intended
to make some remarks on his letter of the 8th of June, as is
mentioned above, yet I afterwards determined to omit these,
since the testimonies of his pupils alone sufficiently proved that
he had no right to those discoveries. By these means I re-
duced the publication to half a sheet of paper : in which I first
gave an account of his claim made, by saying " he had seen
those vessels eight years ago ;". then I mentioned, as arguments
against its validity, that I had myself heard him since that time
declare, " he could not find those vessels," and that, besides, I

102 APPENDIX.

had a note taken at his lectures by a gentleman within two
years of his making it, which contained a similar declaration,1
and afterwards I said that I had written to such gentlemen as
I knew had, as well as myself, attended his lectures within
these eight years, desiring them to consult their notes, and to
let me know what Dr. Monro had said as to the existence, or
non-existence, of the lacteals and lymphatics in these animals ;
without mentioning the dispute between us, or any opinion I
had formed, that they might be unprejudiced to either party.
And that such of these gentlemen as had taken notes sent me
excerpts from them, which, as I had suspected, agreed with
what I had myself heard the professor say upon that subject.

That Dr. Haygarth, physician at Chester, had sent me the
following passage from the notes which he had taken in 1764.

" Fowls, and some fish," says Dr. Monro, " have not lacteal
vessels that we can see ; they have no conglobate glands in the
mesentery ; perhaps they (the lacteals) do not run into each
other, but into red veins, and hence never are so large as to
become visible."

" This note," adds Dr. Haygarth, " was taken in 1764, and
if Dr. Monro had changed his sentiments on this subject in
the year 1765, 1 should certainly have taken notice of so remark-
able a circumstance."

That, from Mr. Orred, surgeon at Chester, who attended
Dr. Monroes lectures during the winter 1765-6, I had learned,
that Dr. Monro, when he spoke of the anatomy of a cock,
declared : " he never saw, or observed any glandulse vagse, or
lacteals, but had seen lymphatics in the neck, ending in the
jugular."2

1 Dr. Monro has misinterpreted this passage. He supposes I meant that this note
was taken two years before 1762, whereas I meant two years before 1768, the time
when he claimed these discoveries, and when I wrote my letter to the Secretary of
the Royal Society. The note itself is printed above, p. 98.

Dr. Monro has taken notice of another inaccuracy, that is, where I had said, " He
asserted that he had anticipated me in these discoveries;" instead of saying, "that
he claimed them by asserting he had injected," &c. The former Dr. Monro seems
to allow to be what he meant, but not exactly what he said. It was therefore a
small inaccuracy ; but his claim is now printed verbatim. See above, p. 96.

2 It may be necessary to mention here, that the dispute between Dr. Monro and
me is, who first discovered the lacteals of birds ? for as to the lymphatics in their
necks, (mentioned in this gentleman's note,) these we both allow were discovered by
Mr. John Hunter, about ten years ago.

APPENDIX. 103

That, from some notes, said to be copied from those taken
by Dr. Taylor of Reading, in the winter 1765-6, 1 had procured
the following excerpt ; and Dr. Taylor, on being requested to
consult his own copy, had acknowledged it was a just one.

"The lymphatic system" says Dr. Monro, "is said to take
place only in men and viviparous animals, and from analogy
in those fishes placed by Linnaeus, under the class of mam-
malia i1 how far is their just extent is not certain, but we
have found them in some amphibious animals, as in the turtle.2

" It is said that this system is wanting in oviparous animals ;
but this is not universally true; for we mentioned that we
found them in a turtle, and they would probably be found in
other orders and genera, if properly examined. But admitting
that they are not demonstrable there, it doth not follow that
they are wanting ; for perhaps they may run only a little way,
and terminate in red veins. "

That Dr. Maddocks, physician to the London Hospital, had
favoured me with the following excerpt from notes which he took
at Dr. Monro's lectures, in the winter 1765-6.

" Lymphatics are found in viviparous animals, and therefore,
I presume, in the whale, which is of this kind. They are not
to be found in oviparous ones, fishes, nor the amphibia : this
is the common doctrine. / will not say how far they may be
found in some birds, but I have found them in some of the
amphibious animals, as in the turtle, running along the root of
the mesentery."

That Mr. Hull, surgeon at Stevenage, had sent me the fol-
lowing excerpt from his notes, taken about four years ago.

" I never could, to this day" says Dr. Monro, "find a single
branch of a lacteal in the abdomen of fowls, nor any lacteals,
or glands of the conglobate kind in the mesentery, notwith-
standing I have made experiments with that view very often.
I kept fowls twenty-four hours without food, then fed them

1 In the excerpt it is amphibia ; but it is evident from the sense, and from com-
paring it with the other notes, that it should be mammalia.

3 As to the lacteals of the turtle, there is no doubt but that Professor Monro and
myself have both discovered them. He, in the summer 1765; I before that time,
viz. in the autumn 1763 ; when I took a short description of those vessels, which is
published with my paper on the lymphatic system in birds, in the 58th volume of
the Philosophical Transactions.

104 APPENDIX.

with bread soaked in milk, and tinged it by turns with blue,
madder, and saffron, and afterwards opened them at several
different times, in order to discover the lacteals, but all without
success. Yet, perhaps, the lacteals may be in fowls, though
not demonstrable." This, adds Mr. Hull, I will answer for
being verbatim, or nearly so, as Dr. Monro delivered it in
the anatomical hall, at Edinburgh, on the 13th of February,
1765.1

These passages, I added, were sufficient to show how little
right Dr. Monro had to these discoveries, Besides, I said it
was a strong argument against him, that in the letter I had
received (which he has printed in his ' State of Facts/ p. 8,)
he could not, after relating all his experiments and observations,
conclude he had really seen those vessels as he had told the
Royal Society ; but in one place he says, " that, from the pre-
ceding experiments, &c. it is evident that he had seen what he
suspected to be the lacteals in birds." And in another, " that
he was himself persuaded that birds were provided with lacteal
vessels, and confirmed in this opinion, by having now injected
them in one of the same oviparous class, the turtle/'2

Such conclusions appear merely evasive, and never can be
considered as proofs of his having discovered those vessels
before I did, agreeably to his assertion read before the Royal
Society, and since repeated in his ' State of Facts/

The half-sheet of paper, containing these arguments and
testimonies against Dr. Monro, was printed Dec. 1, 1769, and
was given to such gentlemen of my acquaintance as had heard
of his claim, and a copy of it was sent to the Doctor. Upon
receiving which, he published his * State of Facts ? but what is
singular, he has attempted his justification without taking pro-
per notice of these testimonies against him ; as if he could be
justified whilst they remain unanswered. And in this ' State
of Facts', in spite of those testimonies, he repeats to us, " that
long before 1762, he observed blueish vessels in the mesentery

1 If the reader will take the trouble of comparing this note with Dr. Monro's own
account of his experiments, (State of Facts, p. 12,) he will be convinced how accu-
rately this gentleman must have taken notes.

2 This argument was repeated in a note, to prevent Dr. Monro's writing ; as if the
dispute between us was, who first had suspicions about those vessels, instead of who
first discovered them.

APPENDIX. 105

(of birds) which he judged to be the lacteals, and had mentioned
as such in his lectures."1 And again, "that about the years
1759-60, he had seen collapsed blueish vessels, which he con-
cluded lacteals, &c."2 What shall we say of this?

Nay, Dr. Monro has, upon this occasion, even ventured
another assertion, viz. " that the notes of his pupils taken for
three years before 1762, will be found to prove, that he then
taught the direct contrary" of what I have brought these testi-
monies to prove he has since taught.3 Now, surely this is very
improbable ; and Dr. Monro should have adduced some testi-
monies to prove it. But supposing it were true, it would lead
to a conclusion unfavorable to him. It would show, that he
must have misled either the one set of gentlemen or the other;
for he says, he told the first he had seen the lacteals ; the
last prove he has since taught them that he never could see
those vessels.

The reader, I fancy, by this time thinks with me that Pro-
fessor Monroes claim deserves no more of our attention. But
as he has printed some excerpts from his own book of notes,
with the parade of having them authenticated, as if they con-
tained the discovery, notwithstanding the above-mentioned
proofs of his having acknowledged repeatedly since he wrote
them, that he never could find those vessels, I shall next, there-
fore, make some remarks upon his notes.

To begin with those relating to the turtle. He discovered
its lacteals in the summer 1765. I had seen them before that
time, viz. in the autumn 1763. Besides, I have since injected
and traced out the whole system ;4 he does not even pretend to
have done so : it is, therefore, not difficult to determine who
was the first discoverer, and who had carried the discovery
farthest.

Next, as to the lacteals in fish. To prove that he had found
those vessels eight years ago, he tells us, that in a note taken
from the dissection of a skate on April 24, 1760, he has said,
" He had discovered a whole system of lacteals and lymphatic
vessels running towards the heart, on the left of and above
the vena portarum, and from these the auricle of the heart was
blown up. They are proportionally larger, but have fewer

1 State of Facts, p. 4. 3 Ibid. p. 26, in the note.

2 Ibid, p. 27. 4 See Philosophical Transactions, vol. Ixix.

106 APPENDIX.

valves than in man."1 Now I will take upon me to say,
there is nothing in this note which proves whether he had in-
flated a lacteal or a vein. For what he says of the situation of
the vessels, and of his blowing up the heart, is equivocal : the
only part of the note which appears to characterize the lacteals,
is in reality a mistake ; that is, where he says they have valves.
But the lacteals on the mesentery of a skate have no valves,
and injections pass readily from the large to the smaller
branches. And what is even more to the purpose, although it
appears, from his calling what he saw lacteals and lymphatics,
that he had at that time some suspicions about them. Yet I
am persuaded he has since changed his opinion; and this I
think is evident, even from the manner in which he speaks of
his experiments made the year after. For, says he, " I have
dissected this year (1761, in summer) eight skates, and about
a like number of cods and codlings, but without being able
to observe by dissection, or to inflate any like to lacteal or
lymphatic glands — I find indeed (he adds), that blowing back-
wards in the meseraic veins, the intestines and the cellular
substance between their coats are inflated ; but this is no
direct proof of branches of red veins absorbing, as these veins
may be burst, or the air may have first entered the arteries."3
Now this surely is not the language of a man who had seen
the lacteals, but of one that was seeking for them. Had he
found them, he certainly would have mentioned it in this note,
but he avoids the subject entirely, and only says he could not
find the glands, thereby leaving us to suppose that these dissec-
tions were made for the glands only, after having discovered
the vessels ; which is highly improbable, since, by his own
confession,8 he did not inject the vessels, which he knows well
enough is the best way of determining whether the glands
exist or not ; and one experiment in this way would have been
more satisfactory than his eight, or than eight hundred made
by dissection only.4 Add to this, he would not, I think, if he

1 See State of Facts, p. 12. 2 Ibid. p. 12. 3 See his claim above, p. 96.

4 If the reader should happen not to be well acquainted with this part of anatomy,
he may not see all the force of this argument, which will be satisfactory to anato-
mists ; for it is a fact admitted amongst them, that the mesenteric glands are placed
only in the course of the lacteals, so that the lacteals must pass through these glands
in their way to the heart. The readiest method therefore of discovering the glands >
after having seen the vessels, is by injecting those vessels ; for the injection, in its

APPENDIX. 107

had now seen the lacteals, have taken up his time with trying
whether the red veins did the office of absorption for them, as
he seems to have done by blowing into these veins. Nay,
I will go farther, and will take upon me to say that it is pro-
bable he was in these last dissections convinced he had been
mistaken in what he took the year before for lacteals and
lymphatics. This I think evident, both from the notes above
mentioned, and from his manner of treating the subject since
that time. For if he thought he had seen those vessels, he
would doubtless have used this discovery as an argument
against absorption by the common veins, as he has since used
that in the turtle. But it appears, from the notes of his
pupils,1 and even from his own account of those arguments,2
that he has not done so. And again, had he thought he had
discovered those vessels, he would not have acknowledged in
his lectures since that time, that they were not yet known to
exist.3 He has therefore aggravated the impropriety of his
conduct in claiming these discoveries, by the disingenuity of
sending such notes as proofs of his claim.

And lastly, as to the lacteals in birds, he tells us, " that in
1758, he remarked a vessel making an arch on the mesentery
of a cock, which at first he believed to be a trunk receiving the
lacteals, but not being able to inject it on trial, he conjectured
to be rather a nerve." And afterwards, in April 1759, " he
observed in a cock what looked like lacteal vessels collapsed, of
a blueish colour, which seemed to terminate at the back-bone,
&c. — These he showed to the students." And, again, after
relating the manner of making his experiments upon no less
than twelve cocks/ he tells us, " that in 1761 he observed, in
the interstices of the great arches of the red mesenteric vessels
a pellucid network, some part of which seems to be composed

way to the heart, must distend the glands, and make even the smallest of them
visible. The vessels seen by the Doctor seem to have been very large ; can it be
supposed then, if he had been convinced they were lacteals, that he would not have
injected them, and thus have determined whether they were glands or not, by one
experiment, instead of tediously dissecting sixteen fish ?

1 See his pupils' notes above, p. 102, &c.

a See State of Facts, p. 16.

3 See the notes of his pupils above, p. 102.

4 The experiments were made by feeding these birds with oatmeal and madder,
oatmeal and rhubarb, &c. See State of Facts, p. 12.

108 APPENDIX.

of branches sent from a large nerve, running parallel with the
intestines, and nearer to them than where the trunk of the
mesenteric artery sends off its large branches ; but although
(says he) I suspect strongly there are here too numerous lac-
teals, and I even observe very small knots, which I take to be
analogous to our mesenteric glands, yet I have not observed
the above-mentioned kinds of food to make any odds in their
appearance,1 &c." And again, after a variety of other experi-
ments, he says, " he could not observe more than above
described." Now what is there in these notes that can en-
title him to the discovery of the lacteals in birds ? Can his
seeing a blue plexus on the mesentery, which at first indeed he
suspected to be lymphatic, but afterwards to be nervous, and a
part of which, he acknowledges, was in his last experiments
found to be made of nerves, entitles him to it ? or can his dis-
covery of the small knots, which he takes to be analogous to
our glands, entitle him to it ? Certainly not. Birds have no
lymphatic glands on their mesenteries, as I have shown.2 Is
it not therefore plain, from these notes themselves, that he had
not discovered the lacteals in birds ? Has he not repeatedly
since that time acknowledged this in his lectures?3 What
shall we say then to his asserting that be had seen them eight
years ago, and his laying before a respectable Society, and de-
siring his brother to propagate such an assertion ? Or what
shall we say to his persisting in it, or above all to his telling
us, in his last publication (p. 26} " that in these notes the
reader will find the appearance of these vessels after death
really described ?"4

After these notes follow some others, to prove that he had
argued in favour of the probability of the existence of those
vessels in birds and fish ; and a conclusion that he had sup-
posed frogs might have them — and his persuasions that they
must have them (not because he had seen them, but) because
turtles had them. Which are nothing to the purpose, and
ought never to have induced him to claim the discovery, or to

1 State of Facts, p. 12. 2 Philosoph. Transact, vol. Iviii, art. 34.

3 See the notes of his students above, p. 102.

4 Let me beg of the reader again to examine these notes, and then judge of the
propriety of Dr. Monro's affirming they really contain a description of those vessels,
when he has himself put it in the power of the reader t,o observe the contrary.

APPENDIX. 109

say he (actually) had seen them. I cannot therefore think it
worth while to take any farther notice of these conclusions.

It is indeed remarkable that Dr. Monro could persuade
himself he had any original merit even in entertaining such
suspicions and opinions. More than one writer had suspected
those animals had them, and that they themselves had seen
something like them ; for a proof of which the reader need
look no farther than Dr. Hatter's ' Elem. Phys.'1 But as those
writers had given no proofs of their having discovered them,
their suspicions and opinions passed for nothing.

Professor Monro, not satisfied with claiming these discoveries,
has even gone farther ; he has intimated in some parts of his
book that I might have learnt them, or a part of them, from
him. As in p. 4, where he speaks of " my giving an account
of these vessels entirely as my own discovery •" this in p. 6 he
calls " broaching another subject with him •" and complains of
me " for passing in silence what I might have heard him ob-
serve concerning it when I attended his lectures." How Pro-
fessor Monro could pretend that I had learnt anything from
him on this subject, that ought not for his sake to be passed
in silence, is astonishing. What could I learn from one who
has repeatedly since that time acknowledged he never saw these
vessels; that they might be too short to become visible; and
who, at the time I attended his lectures, said he could not
find them, as I have already declared. But as my testimony
will have more weight with the reader, when corroborated with
that of a gentleman unconcerned in the dispute, I shall next
add a copy of some notes taken by Dr. Morgan, now professor
of medicine in Philadelphia, who attended Dr. Monroes lectures
at the same time with myself, and who, at my request, sent
me the following excerpt, taken at his lecture upon the ques-
tion, Whether the common veins absorb or not ?

" Most authors (says Dr. Monro) concurring in opinion that
fowls were destitute of lymphatics, and not being able to dis-
cover them myself, I was led to be of their opinion. I
have already observed, that where conglobate glands are found,
there are lymphatics, and the converse of this proposition,
namely, where there is no conglobate gland, there are no
lymphatics. And there being no conglobate glands to be seen

1 Lib. ii, sect, iii ; lib. xxiv, sect. 2.

110 APPENDIX.

in the mesentery of fowls, nor in fishes, I judged these animals
to be destitute of lymphatics ; but Mr. John Hunter having
discovered conglobate glands in the neck of a swan, put me on
further search, and I then found them plainly in common
fowls, but never could find any lacteals in their mesentery,
though experiments were tried by means of coloured tinctures
of various sorts, as of rhubarb, &c."

From this excerpt it is evident that Professor Monro, when
I attended his lectures, taught, as he has since done, that what
he knew of the lymphatics he learned from Mr. Hunter, and
as to the lacteals he could not find them ; and this was in the
spring 1762, the very year after the time when, according to
his letter read before the Royal Society, he should have seen
these vessels, and mentioned them in his lectures : and finally,
to complete the whole, he now complains of me for passing in
silence what I might then have heard him observe concerning
them.

Thus have I endeavoured to obviate the arguments in Dr.
Monro's publication, and the reader must now, I think, see
clearly, not only the impropriety of the Doctor's asserting his
right to these discoveries, but the still greater impropriety of
his persisting in that assertion.

Besides claiming these discoveries, Dr. Monro has, in his
letters on the subject, treated me in a manner which I cannot
pass unnoticed. Thus, he first gives the name of misinterpreta-
tion to my concluding from the notes of his pupils, that he had
not seen " what he believed" the lacteals, and then adds :

" Should we even suppose the above misinterpretation venial,
what must the reader think, when he is told, you was informed
that a gentleman, who had attended my lectures two years at
least before I injected the lacteals of a turtle, that is, nearly
about the time you did, declared he heard me then speak of
having seen the lacteals in fowls ; and yet that you continued
to vent this injurious supposition? That is, you must have
sunk this material information, since it overturned the whole
purport of your story/'1

Now here is an accusation, which, were it true, would fall
heavy upon me. But the case is this : I had indeed heard that
a gentleman, who attended Professor Monro' s lectures about the
1 See his State of Facts, p. 23.

APPENDIX. Ill

time I did, had declared he then understood the Professor had
seen the lymphatics in birds. And Dr. Donald Monro, when
I saw him at St. George's Hospital, asked me if I had not
heard that this gentleman (mentioning his name, viz. Dr. James
Blair, then in London, now in Virginia) had said that the Pro-
fessor had then mentioned his having seen the lacteals in birds.
I answered Dr. Donald, that I had heard something of the
matter, but could conclude nothing from it (or to that effect).
The reason was this : I knew from the testimony of my own
memory, that the Professor had then acknowledged the con-
trary of his ever having seen the lacteals.1 I knew the same
from the testimony of gentlemen who had attended his lectures
since. I therefore concluded that this gentleman had con-
founded his saying he had seen the lymphatics, with his saying
he had seen the lacteals, which I thought might easily happen,
as I never knew him take any notes. And upon receiving the
Professor's letter, I wrote to Dr. Blair, and in his answer he
acknowledged, " that although he had, indeed, for several years,
been under a general persuasion that Dr. Monro had seen the
lacteals or lymphatics in fowls, yet he had no note on the sub-
ject, and a very confused remembrance of what he had heard/'

Similar to this accusation is the greater part of a letter
which I received from Dr. Monro, in answer to two of mine.
This letter is dated Sept. 30, 1769. The Doctor has not printed
it, but I beg leave to take a little notice of it.

He begins it by altering the sense of his assertion read
before the Royal Society, by the introducing the word believed,
making it rather a doubtful than a positive assertion. He has
done the same in the beginning of his 'State of Facts,' qualifying
the alteration, by adding, " to the best of his recollection, and
that he had not kept a copy of his letter, not supposing it
material to do so/'2 But surely this was not sufficiently
qualifying it. If he did not know exactly what he had then
asserted, why, before he defended it, did he not ask a copy
from his brother, who, most probably, would keep it, in order
to show it to everybody; or solicit that favour from the secre-
taries of the Royal Society where it was read, who, he might be
sure, had preserved it, as they do every paper that is laid before

1 Dr. Morgan's note proves he did so, see above, p. 109.

2 See State of Facts, p. 5.

112 APPENDIX.

the Society. And again, if he was not sure of its contents, how
could he now venture in his ' State of Facts/ positively to
insist, in opposition to what I had declared, " that his first and
last assertions were exactly the same."1 This at least was
inexcusable.

Next, he repeats his vague inferences as in his letter of the
8th of June, " that he had seen what he suspected to be those
vessels, &c.," and afterwards, when he comes to speak of the
conclusions concerning his claim, which I made in my letter
read before the Royal Society, he says, " that he was almost
ashamed, on my account, to add a plain corollary, that I must
or might have been conscious, that the injurious conclusion
with respect to him, which I was labouring to impress on the
members of a respectable Society, was drawn from arguments
that were weak, inconclusive, not real, but feigned." { After-
wards, he tells me, that he is glad, on my account as well as
his own, that I am at last really ashamed of my letter." And
he then finishes with the following passage : " Another unhappy
mistake of yours," says he " is, that you should not have known,
or rather perhaps misfortune of yours, since you do not seem
to have known so much, that you should not have been told,
that your presuming to draw the above conclusion concerning
any person who had the smallest pretence to character, without
producing proof and absolute certainty of its being true, was
what you never could be able to justify to any gentleman."

Now, when it is considered that Dr. Monro obliged me to
act in the manner I have done, in order to secure my right,
do not these passages appear very extraordinary? But the
reader, I believe, will excuse my not dwelling upon them. I
shall therefore only add, that the proofs on which my con-
clusions were founded being now laid before the public, to
their judgment I willingly submit them, and that, with respect
to Dr. Monro, I have nothing more to say, than that I hope,
for his sake as well as my own, to see no more of his claims,
his assertions, and his conclusions.

1 State of Facts, p. 26, in the note.

2 The conclusions alluded to in these passages are printed above, pp. 97, 98.

EXPERIMENTAL INQUIRIES,

PART II.
A DESCRIPTION

THE LYMPHATIC SYSTEM

HUMAN SUBJECT, AND IN OTHER ANIMALS.

ILLUSTRATED WITH PLATES.

TOGETHER WITH OBSERVATIONS ON THE LYMPH, AND THE CHANGES
WHICH IT UNDERGOES IN SOME DISEASES.

BY WILLIAM HEWSON, F.R.S.

AND TEACHER OF ANATOMY.

LONDON :

MDCCLXXIV.

8

Atque in anatomia corporum organicorum (qualia sunt hominis et
animalium) opera sane recte et utiliter insumitur ; et videtur res sub-
tilis et scrutinium naturae bonum. — LORD BACON.

TO

BENJAMIN FRANKLIN, ESQ., LL.D., F.R.S.

THIS ESSAY
IS RESPECTFULLY INSCRIBED,

BY HIS MUCH OBLIGED,
AND MOST OBEDIENT HUMBLE SERVANT,

WILLIAM HEWSON.

PREFACE.

THE science of anatomy has now been so long and so suc-
cessfully cultivated, that most parts of the human body have
been both carefully described and accurately delineated; but the
vessels which are the subjects of this essay, having only of late
been made known to anatomists, and not being easily traced by
dissection, have not been completely described, nor have they
ever been delineated. The following, therefore, is an attempt,
in some measure, to supply these deficiencies j and the author
flatters himself, that when it is considered how great a share
those vessels have in the composition of our body, and how
important the offices are which they perform, that this small
addition to the stock of Anatomical Science will not be unac-
ceptable, either to the practitioners of the healing art, or to the
philosophical inquirers into the works of nature.

THE LYMPHATIC SYSTEM,

CHAPTER I.

A SHORT HISTORY OP THE DISCOVERIES MADE IN TffE
LYMPHATIC SYSTEM.

' < SINCE the days of Asellius, of Rudbeck and of Bartholin,
who by their successful inquiries first proved the existence of
those vessels in the human body which are now called the
Lymphatic System, no part of anatomy has more engaged the
attention of its professors; partly from its being the largest
field that has lately been opened for their cultivation, and
partly from their being so thoroughly persuaded of its great
importance.

Asellius, in the year 1622, reaped the first laurels in this
field, by his discoveries of those vessels on the mesentery,
which, from their carrying a milk-like fluid, he denominated
lacteals.1 This discovery being made by opening a living dog,
anatomists were thence encouraged to make experiments on
living animals; and Pecquet, on opening a dog in the year
1651, found a -white fluid mixed with the blood in the right
auricle of the heart. Suspecting this fluid to be chyle, he
endeavoured to determine how it got from the lacteals into
the heart; this he found was by means of the ductus thoracicus,
which he traced from the lacteals to the subclavian vein,2 and
thus lie clearly proved the existence of that duct which we
now consider as the trunk of the system. Just before his time
the lacteals had been supposed to terminate in the liver, con-
formably to the idea which the physiologists of that period had

1 Asellius de Lact.

• Pecquet Exp. Nova Anat. fig. 2, in Hemsterhuis Messe Aiirea.

120 LYMPHATIC SYSTEM.

adopted about the use of this organ, which, from the authority
of the older anatomists, they believed was the viscus hsemato-
poieticum, or that received the chyle from the intestines to
convert it into blood.

Next, Rudbeck, anno 1651,1 Dr. Jolyffe,2 and Thomas Bar-
tholin, about the year 1652,3 discovered the other parts of this
system, which, from their carrying a transparent and colourless
fluid, are called the lymphatic vessels. And thus there was
proved to exist in an animal body a system of small vessels
carrying fluids very different from the blood, and opening into
the sanguiferous vessels at the left subclavian vein.

To Asellius, Pecquet, Rudbeck, Jolyffe and Bartholin, we
are therefore indebted for the discovery of the different parts
of this system ; not but that some of these vessels had been
seen and mentioned by their predecessors, but it was in too
cursory a manner to give them any title to the discovery.4

After this period Nuck added to our knowledge of this system
by his injections of the lymphatic glands,5 and Ruysch by his
description of the valves of the lymphatic vessels,6 and Dr.
Meckel by his accurate account of the whole system, and by
tracing those vessels in many parts where they had not before
been described.7

Besides these authors, Dr. Hunter and Dr. Monro have
called the attention of the public to this part of anatomy, in
their controversy concerning the discovery of the office of the
lymphatics (LXI).

When the lymphatic vessels were first seen and traced into

1 01. Rudb. Exercit. Anat. cap. i, in Hemsterhuis Messe Aurea.

2 Glisson de Hepate, cap. xxxi.

3 Barthol. de Lacteis Thoracis, in Hemsterhuis Messe Aurea.

4 Thus the lacteals had been seen in kids by Erasistratus, who calls them arteries,
as we are informed by Galen. See Galen Oper. torn, i, p. 61, edit, apud Junt. The
thoracic duct had been seen by Eustachius, who speaks of it as a vein of a particular
kind. See Eustachius de Vena sine Pari.

8 See his Adenographia. 6 In his Delucidatio Valvularum.

7 Epistola ad Hallerum.

(LXT.) See the Introduction. The controversy alluded to by Mr.
Hewson will be found in the ' Observations, Anatomical and Physio-
logical, wherein Dr. Hunter's claim to some discoveries is examined,
by Alexander Monro, junior, M.D.' 8vo, Edinb. 1758; and 'Medical
Commentaries, Part I, containing a plain and direct answer to Professor
Monro, junior, by William Hunter, M.D.' 4to, Lond. 1762.

LYMPHATIC SYSTEM. 121

the thoracic duct, it was natural for anatomists to suspect,
that as the lacteals opened into the intestines to absorb, the
lymphatic vessels (which are branches of the same system)
might possibly do the same office with respect" to other parts
of the body ; and accordingly Dr. Glisson, who wrote in 1654
(that is, the very year after Bartholin published on the lym-
phatic vessels), supposes these vessels arose from cavities, and
that their use was to absorb ; and Frederic Hoffman has very
explicitly laid down the doctrine of the lymphatic vessels being
a system of absorbents.1 But anatomists in general have been
of a contrary opinion ; for, from experiments, particularly such
as were made by injections, they have been persuaded that the
lymphatic vessels did not arise from cavities, and did not ab-
sorb, but merely were continued from small arteries. The
doctrine therefore that the lymphatics, like the lacteals, were
absorbents, as had been suggested by Glisson and by Hoffman,
has been revived by Dr. Hunter and Dr. Monro, who have
controverted the experiments of their predecessors in anatomy,
and have endeavoured to prove that the lymphatic vessels are
not continued from arteries, but are absorbents.

To this doctrine, however, many and strong objections have
been started, particularly by the learned M. de Haller,2 and it
has been found, that before the .doctrine of the lymphatics
being a system of absorbents can be established on a solid
foundation, it must first be determined, whether other animals,
besides man and quadrupeds, have or have not this system. I
have been so fortunate as to prove the affirmative of this ques-
tion, by discovering the lymphatic system in birds, fish, and
amphibious animals,3 and in consequence of these discoveries I
have also arrived at the knowledge of considerable varieties in
the composition of those vessels through the various classes of
animals; by comparing this knowledge with some facts that
I have lately observed concerning the blood, I have thence
been led to ascertain the use of the lymphatic glands, the thy-
mus, and the spleen ; which have so long been considered as
the opprobria of anatomists.

These last observations I propose making the subject of a

1 See further on, chapter x. 2 Elem. Phys. lib. xxiv, sect. 2, 3.

3 Accounts of which have already been published in the Phil. Transactions, vols.
Iviii, lix.

122 LYMPHATIC SYSTEM.

future publication ;* but in order to prepare the reader for it,
I have thought it necessary to lay before him a description and
comparison of the lymphatic vessels in different animals. And
that this may be the more worthy his attention, I have not
only traced those vessels in most parts of the human body as
Dr. Meckel has done, but I have observed some circumstances
which had escaped his notice ;" and I have illustrated the
description with plates, the necessity of which has appeared so
strongly to some who have preceded me in this subject, par-
ticularly to Messrs. Monro, Meckel, and Hunter, that they have
each promised to supply the deficiency, but none of them
having yet done it, I have undertaken the task myself, that I
may be able to refer the reader to the facts from which my
conclusions are made.

1 An abstract of these discoveries, though an imperfect one, has heen published in
the Medical Commentaries of Edinburgh, No. 1, but without my concurrence (LXII).

(LXII.) See ' Medical and Philosophical Commentaries, by a Society
in Edinburgh/ vol. i, p. 99, 8vo, Lond. 1773 ; and the Letter to Dr.
Haygarth, republished in the present edition of Mr. Hewson's works.
His views concerning the glands without regular ducts are given at
length, by Mr. Falconar, in the Third Part of the Experimental
Inquiries.

CHAPTER II.

A GENERAL ACCOUNT OF THE LYMPHATIC SYSTEM.

THE lymphatic system consists of the lacteals, the lymphatic
vessels, their common trunk the thoracic duct, and the glands
called conglobate.

The lacteals begin from the intestinal tube, and can readily
be seen in a dog or other quadruped that is killed two or three
hours after eating, when they appear filled with a'white chyle.
The experiment succeeds best when the dog is fed with milk ;
but they do not always convey a white fluid, for, even in a
dog, if opened long after a meal, they are found distended
with a liquor that is transparent and colourless like the lymph ;
and in birds I have never found the chyle white, but always
transparent and limpid (see Note LIX) ; these vessels, therefore,
might with as much propriety be called the lymphatics of the
intestines.

The lymphatic vessels are small pellucid tubes that have
now been discovered in most parts of the human body ; the
fluid they contain is generally as colourless as water, a circum-
stance which procured them at first the name of ductus aquosi,1
and afterwards that of vasa lymphatica.2 The course of the
lymph, like that of the chyle, is from the extreme parts of the
body towards the centre, and the lymphatic vessels commonly
lie close to the large blood-vessels. If, therefore, a ligature be
made round the large blood-vessels of the extremity of a living
animal, or of one just dead, that ligature, by embracing the
lymphatics, will stop the course of the lymph, which by dis-
tending the vessels will make them visible below the ligature.

All the lacteals and most of the lymphatic vessels open into
the thoracic duct, which lies upon the spine and runs up towards
the neck of the animal, where it commonly opens into the
angle between the jugular and subclavian veins of the left

1 See Rudbeck, 1. c. 2 See Bartholin, 1. c.

124 LYMPHATIC SYSTEM.

side, and thus both the chyle and lymph are mixed with the blood.
If, therefore, the thoracic duct be tied instantly after killing an
animal, not only the lacteals, but also the lymphatics in the ab-
domen and lower extremities become distended with their natural
fluids, the course of those fluids being stopped by the ligature.

The lacteals, the lymphatics, and the thoracic duct, all agree
in having their coats more thin and more pellucid than those
of the blood-vessels. But although their coats are so thin they
are very strong, as we daily see on injecting them with mercury,
since they resist a column of that fluid, whose weight would
make it burst through blood-vessels, the coats of which are many
times thicker than those of the lymphatic system.

The thinness of the coats prevents our dividing them from
one another, and thereby ascertaining their number, as we do
those of the blood-vessels. But as the blood-vessels have a
dense internal coat to prevent transudation, we have reason to
believe the lymphatics have the same. And as the blood-vessels
have a muscular coat, which assists in the circulation,1 so may

1 The existence of the muscular coat of the blood-vessels has been rendered pro-
bable by Dr. Verschuir's experiments, wherein these vessels were found to be irri-
table, and also by the following circumstance which I observed in dissecting an ass.
The arteries of this, like those of other animals, have a strong elastic coat, which
coat after distension contracts them again to a certain degree ; but this contraction
never goes so far as to shut up the cavity of the artery, and as it acts equally in the
dead as in the living body, large arteries are therefore always found with considerable
cavities. But in this ass, which I bled to death, the arteries contracted more than
their elastic coats were capable of doing ; for those of the kidneys were without a
cavity, and resembled a cord ; and that this contraction was muscular appeared upon
distending them again, in which case they stood open as they commonly do in dead
bodies. This fact will help us to explain why the arteries appear empty in dead
bodies; which may be owing to their muscular fibres having (before death) con-
tracted to the degree seen in this animal, by which means all the blood was driven
into the veins ; but these muscular fibres ceasing to act after death, the elastic fibres
overcome that contraction, and expand the arteries which therefore appear empty
(LXIII). Since writing the above, I have dissected a still-born child which was de-
fective in many parts of the body, and in particular in having no heart. In this child
the circulation had been carried on merely by an artery and a vein, whose coats
therefore probably were muscular.

(LXIII.) Hewson takes no account here of the pressure of the at-
mosphere. Dr. Davya examined the carotid artery of man in nineteen
cases after death, and always found it collapsed, and quite or nearly

a Researches, Physiological and Anatomical, ii, 188.

LYMPHATIC SYSTEM. 125

the lymphatics, as is rendered probable from what Dr. Haller
says of his having found them irritable in his experiments,1
and also from what is observed on seeing them distended with
their lymph in living animals, in which case they appear of
a considerable size ; but upon emptying them of their contents
they contract so much as not to be easily distinguished. This
is an experiment which I have frequently made in the trunk of
the lacteals in a goose and on the lymphatic vessel on its neck,
both of which, when distended with their natural fluids, are as
large as a crow-quill ; but on emptying them in the living
animal, I have seen them contract so much that it was with the
greatest difficulty I could distinguish them from the fibres.2

1 Sur le Mouv. du Sang, ex. 295, 298.

2 See also Haller, El. Phys. lib. ii, sect. 3, $ iii. The celebrated Nuck thought he
could separate the coats of the lymphatics, Adenographia, cap. iii (LXIV).

empty ; but expanding and recovering its cylindrical form when opened
either in the air or under water.

Mr. Hunter a describes the arteries as possessing both a muscular
and an elastic power, the former chiefly acting in the tranverse direc-
tion of the tube ; and the elasticity, " when the muscular action ceases,
being exerted to dilate the vessel and restore it to a middle state again,
becoming the elongator or antagonist of the middle coat, and by that

means fitting it for a new action There appears to be no

muscular power capable of contracting an artery in its length, the whole
of that contraction being produced by its elasticity." Mr. Hunter's
experiments on the functions of the arteries are supported by the latest
and best observations on their structure. Professor Henle5 describes the
proper contractile or middle coat, the muscular coat of Hunter, the middle
or elastic of former writers, as composed of fibres encircling the vessel,
and possessing much the same ultimate structure as the organic muscle
of the stomach and intestines ; while the yellow tissue, or elastic coat
of Hunter, so remarkable in the larger arteries, is situated immediately
external to the contractile coat, has all the microscopic characters of
elastic tissue, and its fibres variously directed. The external or cellular
coat consists of longitudinal filaments of common cellular tissue.

It is well known that the blood may be propelled by the action of

the vessels alone. The heart is sometimes wanting even in a large

human foetus, of which a remarkable instance was described by the

second Dr. Monro.c

(LXIV) The larger lymphatic and lacteal vessels'1 are similar in structure to

a Works, ed. by Palmer, iii, 164-169. c Essays, &c. page civ, ed. by his Son.
b Anatomic Generate, tr. par Jourdan, 8vo, Edin. 1840.

t. ii, pp. 28-34. 8vo, Paris, 1843. d Henle, op. cit. torn, ii, p. 89.

126 LYMPHATIC SYSTEM.

The coats of lymphatic vessels have, in common with all
other parts of the body, arteries and veins for their nourish-
ment ; this is rendered probable by their being susceptible of
inflammation, for they are frequently found in the form of a
cord, painful to the touch, and extending from an ulcer to the
next lymphatic gland, instances of which are mentioned below.1
These painful swellings of lymphatic vessels likewise show that
their coats have sensibility, and therefore that they have nerves
as well as arteries and veins.

The lymphatic system in most animals, but particularly in
man and quadrupeds, is full of valves. These valves have been
painted by the celebrated Nuck, Ruysch, and others, and are
much more frequent than in the common veins, and thence
these lymphatics have sometimes been distinguished by the
name of valvular lymphatic vessels. Those valves are gene-
rally two in number, are of a semilunar shape, and the one is
sometimes much larger than the other. In most parts of the
body these valves are so numerous that there are three or four
pair in an inch of space, but sometimes there is no more than
one pair. They are less numerous in the thoracic duct than in
the branches of the system ; thence it might be supposed that,
in proportion as we go from the trunk to the branches, we
should find them thicker set ; but this is not always true, for
I have observed them more numerous in the lymphatic vessels of
the thigh than in those of the leg. When the vessels are dis-
tended with lymph they appear larger where the valves are,
which sometimes gives a lymphatic vessel an appearance of

1 Chapter xiii.

lyrj

sels contract powerfully in the necks of living dogs. In horses and
dogs killed during digestion, I have several times seen the lacteals well
distended ; and yet contracting so fast in the course of less than an hour,
as to become nearly or completely empty. Miiller'sb discovery of pul-
sating sacs connected with the lymphatic cavities of frogs, is now well
known ; and similar lymphatic hearts, as they are called, have since
been observed, containing lymph and connected with the lymphatic
vessels, in reptiles generally and in birds. See Dr. Jos. J. Allison's
paper, in the American Journ. Med. Sc. Aug. 1838 ; and Mr. Paget's
Report in the Brit, and For. Med. Rev. vol. xix, p. 2/9.

* History of the Absorbent System, p. h Physiology, tr. by Dr. Baly, vol. i,
27, 4to, Loud. 1784. p. 274.

LYMPHATIC SYSTEM. 127

being made of a chain vesicles ; as such they are represented
by some authors : l but it is an appearance that very seldom
occurs j the reader will not observe it in any of the plates
which are here laid before him.

Lastly, the lymphatic system, in different parts of its course,
has the glands called conglobate or lymphatic. These glands
are so placed that the vessels come in on one side and pass out
on the other, in their way to the thoracic duct. Before the
discovery of the lymphatic vessels in birds, fish, and turtle,
some anatomists have considered these glands as so essentially
necessary to the lymphatic system, that they have generally
set about discovering the vessels by first looking for those
glands ; and wherever they found glands they pronounced that
there must be vessels; and when no glands could be seen, they
thought it as certain a proof of there being no vessels. But
as we know the glands are wanting in some animals, I shall
not take notice of their structure and use in this chapter ; but
shall speak of them in a future publication (LXIV*), where I
shall treat of the spleen and thymus, with which they are
connected in their office.

1 See Nuck's Adenographia.

(LXIV*.) See the Third Part of these Experimental Inquiries.

CHAPTER III.

A PARTICULAR DESCRIPTION OF THE LYMPHATIC SYSTEM IN
THE HUMAN BODY.

IT has already been observed that the lymphatic system, be-
sides the glands, is divided into three parts, viz. the lacteals,
the lymphatic vessels, and the thoracic duct. That the lacteals
belong to the intestinal tube, whilst the lymphatic vessels be-
long to all the other parts of the body, and that the thoracic
duct is the common trunk which receives both the lacteals and
the lymphatics. I shall next proceed to give a particular de-
scription of each of these vessels, and shall begin with the
lymphatics of the lower extremities.

The lymphatic vessels of the lower extremities may be
divided into two sets, viz. a superficial and a deep-seated.

The superficial set of lymphatics consists of a considerable
number of vessels that lie between the skin and the muscles,
and belong to the surface of the body or the skin, and to the
cellular membrane which lies immediately under it. Of these
there are two large branches that can be readily enough disco-
vered in the limbs of dropsical subjects; one of which runs upon
the top of the foot, as is represented Plate I, fig. 1, a ; another
can generally be found just under the inner ankle. I have
introduced pipes into both of them, and have thereby filled
them the whole length of the lower extremity, as is seen in
Plate I.

The lymphatic «, which, belongs to the toes, runs up on
the outside of the tendon of the tibialis anticus i, till it has
got above the ankle ; and it divides at b, and again at c, c, c,
forming a plexus, which runs over the shin-bone H, and
ascends in the cellular membrane immediately under the skin,

LYMPHATIC SYSTEM. 12!)

between that bone and the internal belly of the gastrocne-
mius G to the inside of the knee F, where in this figure it dis-
appears, but may be seen in Plate I, fig. 2. This plexus, having
passed the inside of the knee, appears upon the thigh imme-
diately under the skin, and over all the muscles, as is seen in
fig. 1 e, from which it passes to the groin, where these vessels
enter the lymphatic glands.

The lymphatic glands of the groin are six, seven, or eight
in number ; of these some lie in the very angle between the
thigh and the abdomen, and others lie a few inches down, on
the fore part of the thigh. The lymphatic vessels above de-
scribed enter the lowermost of these glands, which in the sub-
ject of Plate I, fig. 1, are four in number, viz. f}f, g,g : one
branch, however, avoids these glands, as at h, which after-
wards bends over at i to the gland k; from which go vessels
to the other lymphatic glands /, / that lie in the angle be-
tween the thigh and the abdomen. It is into these upper
glands alone that the lymphatic vessels of the genitals enter,
so that the venereal bubo, which arises in consequence of an
absorption of matter from these organs, is always seated in
those upper glands, and the lower glands /,/, g,g are never
affected, except by the regurgitation of the matter, or from
their vicinity to the glands first diseased, which very seldom
happens. And as it is the upper glands that are affected by
the absorption of matter from the genitals, so it is the lower
which are commonly first affected from the absorption of the
acrid matter of an ulcer, diseased joint, carious bone (in the
parts below these glands), a circumstance that may assist us in
the diagnosis of those two kinds of buboes ; remembering,
however, that this rule may be liable to an exception, from one
of the lymphatic vessels passing the lower glands, and only
entering the upper, as is seen at h in the same plate.

The lymphatic vessels of the genitals having joined those of
the thigh, a network is formed, which enters the abdomen
under the edge of the tendon of the external oblique muscle,
called Poupart's ligament; one of these vessels is seen in Plate II,
b, b. This plexus on the inside of Poupart's ligament consists
of many branches, some of which embrace the iliac artery, of
which one is seen in Plate II, at c, c, but the greatest number

9

130 LYMPHATIC SYSTEM.

of them pass up in the inside of the artery, as is seen at m, n
Plate I, fig. 1, and at c,c Plate II.

These superficial lymphatics, small as they are/ probably are
the trunks of those vessels which absorb from the skin and the
cellular membrane immediately under it ; and as no considerable
branches can be distinguished on the outside of the leg or
thigh, it is probable that all the lymphatic vessels of those
parts bend towards the inside, and open into the trunks that
are here represented.

Upon these vessels, from the foot to the groin, there is com-
monly not one lymphatic gland. But this rule has likewise
some exceptions, for, even at the lower part of the leg, there
is a very small one in the subject from which this plate was
taken ; it is represented at d Plate I, fig. 1 ; and in another sub-
ject I saw a small lymphatic gland near e, but these, I believe,
seldom occur ; however, they lead to this conclusion, that the
lymphatic glands even in the human body, are in number and
situation a little different in different subjects.

Besides these superficial lymphatic vessels which lie above all
the muscles, or in the cellular membrane under the skin, there
is a set deeper seated, that lie amongst the muscles and accom-
pany the crural artery : of these the principal trunk can be
discovered by cutting down to the posterior tibial artery, near
the inner ankle ; I have introduced a pipe into it at this part,
and have injected it in several subjects, one of which is re-
presented in Plate I, fig. 2.

From the inner ankle at «, Plate I, fig. 2, this vessel passes
up along with the posterior tibial artery, being hid amongst the
muscles on the back part of the tibia. About the middle of the
leg it enters a small gland at c-, and as I have seen this gland in
several subjects, I suspect it will be commonly found. Having
passed through this gland, the lymphatic runs up to the back
part of the ham, still lying close to the artery, and in the ham
it passes through three glands, viz. f,g,h. I have seen a
subject in which I could find only two glands, so that I suspect

1 With respect to the size of these lymphatics, it is necessary to observe that
in this plate all of them appear larger than they ought to be in proportion to the
size of the limb.

LYMPHATIC SYSTEM. 131

the number varies. Hitherto this lymphatic has been a single
trunk ; but after it has passed these glands it commonly divides
into two or three branches, which still accompany the crural
artery, and pass with it through the perforation in the triceps
muscle. This muscle is divided in the preparation from which
this figure was taken, in order to give a better view of the
lymphatics ; and the cut ends of the muscle appear at F, F,
though not very distinctly, from their being shrunk by drying.
The lymphatic vessels having perforated the triceps, pass up
with the artery, (as is seen at k, I) and enter a gland m which
is deeper-seated than those which appear in the groin in Plate I,
fig. 1 ; from this gland they pass into the superficial glands,
represented in Plate I, fig. 1 ft f, g, g, where the lymph of the
deep-seated, and of the superficial lymphatics is mixed, and is
conveyed into the body by the vessels seen just above in the
same plate. At this part likewise the lymph from the genitals
is mixed with that brought by the two sets of lymphatics from
the lower extremities, and the whole enters the abdomen by
the plexus of vessels represented Plate I, fig. 1, at m, and a
part of it at Plate II c.

The lymphatics of the lower extremities having now reached
the trunk of the body, and having passed under Poupart's liga-
ment, appear upon the sides of the ossa pubis near the pelvis at
c, c Plate II. A part of them passes up along with the iliac artery
upon the brim of the pelvis, and another part dips down into the
cavity of the pelvis, and joins the internal iliac artery near the
sciatic notch. At this place they are joined by the lymphatics
from the contents of the pelvis, particularly from the bladder and
the vesiculae seminales in the male, and from the uterus in the
female, and there are likewise a few branches which pass through
the sciatic notch from the neighbourhood of the glutei muscles.
The lymphatic vessels of the uterus, like its blood-vessels, are
much enlarged, and therefore easily distinguished, in the preg-
nant state of that organ. At this part, where so many lym-
phatic vessels join, there is commonly one or two glands.

Besides those lymphatic vessels which dip down into the
cavity of the pelvis on the inside of the external iliac artery at
c, c Plate II, there are others which keep on the outside of
that artery upon the psoas muscle, some of which are seen on
the left side in the same Plate at d ; of these one part passes

132 LYMPHATIC SYSTEM.

up to the loins at h, and goes under the aorta in different
branches, getting from the left side to the right, and joining
the thoracic duct. Another part passes under the iliac arteries
and appears upon the os sacrum at /, making a beautiful
network, joining the lymphatics of the right side, and passing
under the right iliac artery, to form the network g upon the
upper part of the right psoas muscle. In different parts of
this course from Poupart's ligament to the loins, and also in
the loins themselves, there are, in most subjects, many lymphatic
glands ; none of which were filled in the subject from which
this plate was made.

The lymphatic vessels of the right side, joined by some from
the left, having now reached the right lumbar region, appear
there in the form of a plexus of large vessels, and pass through
several glands, which in this subject occupied the spaces (i, i, i}}
but not being injected with mercury are not represented ; at
this part likewise they receive large branches, under the aorta,
from the plexus on the left side of the loins, as is mentioned
before, and having at last got up as high as the second lumbar
vertebra, they all join, and form a single trunk called the tho-
racic duct, which is seen at m Plate II. At this part they are
likewise joined by the lacteals, which I shall next describe.

The lacteal vessels, so called from their commonly conveying
a fluid that is of the colour of milk, begin from the inner sur-
face of the intestines, where they have patulous orifices (see
Note LXXXIII) destined to imbibe the nutritious fluid or chyle ;
from the cavity of the intestines these vessels pass obliquely
through their coats, uniting as they go so as to form larger
branches. These branches run on the outside of the gut to
get to that part which is next the mesentery ; and, whilst they
are yet upon the gut, they are sometimes of a size sufficient to
admit a small pipe, so that I have injected them with mercury
even in the human subject.

From the intestines they run along the mesentery and meso-
colon, towards the spine, and in their way they pass through
the conglobate or mesenteric glands, which in the human sub-
ject are very numerous. These glands divide the lacteals into
two regions; for from the intestines to the glands these vessels
are called lactea primi generis, and from the glands to the
thoracic duct, lactea secundi generis.

LYMPHATIC SYSTEM. 133

The lacteals of the small intestines, as they run upon the
mesentery, commonly accompany the superior mesenteric artery,
and unite, as they go on, into larger branches, so that by the
time they have reached the root of the mesentery, they are of
a considerable size, as may be seen in Plate II at k • from
the mesenteric artery they pass down by the sides of the aorta,
and open into the thoracic duct, as is seen at m. Whilst
the lacteals, or rather the lymphatics of the large intestines,
accompany the inferior mesenteric artery, and open into the
large lymphatic vessels near its root.1

Into the thoracic duct at m, likewise enters the lymph of the
other viscera contained in the abdomen. This lymph is brought
by a number of vessels ; a plexus of which may be traced from
each kidney, lying principally behind the emulgent artery, and
opening into the large lymphatic vessels near the aorta : with
these likewise go the lymphatics of the glandulse renales, or
renal capsula3, as they are called.

The lymphatic vessels of the spleen pass from the concave
side of that viscus, along with the splenic artery in the sinuosity
of the pancreas, by the lymphatic vessels of which the splenic
lymphatics probably are joined.

The stomach has two sets of lymphatic vessels, the one run-
ning upon its lesser, and the other upon its greater curvature ;
that which belongs to its lesser curvature accompanies the coro-
nary artery, and passes through some lymphatic glands that
lie by its sides. The other set of lymphatic vessels passes from
the great curvature of the stomach, through some lymphatic
glands that lie close to the arteria gastrica dextra; and de-
scending by the pylorus, meets the plexus that accompanied
the coronary artery ; and near the lesser curvature of the duo-
denum, forms a considerable network : into which not only the
lymphatics from the spleen enter, but likewise those from the
gall-bladder ; and those of the liver, which are very numerous,
both in its convex and on its concave side.2 From this net-
work go some branches under the duodenum, and others over
it, these branches open into the thoracic duct, near the termina-

1 The lymphatic vessels arise even from the rectum, as can be seen in quadrupeds
that are opened immediately after death ; or in fish when a coloured injection is
thrown into their lymphatic system.

2 The lymphatic vessels of the liver are painted by Nuck in his Adenographia, p. 64,

134 LYMPHATIC SYSTEM.

tion of the large trunk of the lacteals, as seen at m Plate II.
The thoracic duct therefore is the common trunk which receives
the lymphatic vessels of the lower extremities, the lacteals, and
the lymphatics of all the abdominal viscera.

With respect to the lymphatics of the larger viscera, (such
as the liver, the spleen, and the kidneys,) they are generally
in two sets : one which lies upon the surface of the organ, and
the other which accompanies the large blood-vessels in its centre.
In the liver I have found these two sets communicate with
each other, so that by injecting mercury into the lymphatic
vessels which lie upon its convex surface, I have filled those
which accompany the pori bilarii and vena portarum in its
centre. The greatest part of the lymphatic vessels which lie
upon the convex surface of the liver, run towards its falciform
ligament, and pass down by the side of the vena cava. But
some of them run towards the right ligament of the liver,
where they pass down upon the diaphragm to get to the tho-
racic duct. The lymphatics on the concave surface run towards
the portae where they join those which come from the centre
of the liver along with its large blood-vessels ; it is remarkable
of those lymphatic vessels which run upon the surface of the
liver, that their valves can readily be made to give way, so
that I have injected them from their trunks to their branches,
and to great minuteness ; some preparations of which I have
now by me.

It has been suggested by one of the best anatomists of this
age,1 that the lymphatics of the stomach do not open into the
thoracic duct like those of the other viscera, but only open into
the sanguiferous veins of the stomach ; but from repeated dis-
sections of the human subject I am convinced of the contrary ;
and likewise from the analogy with other animals, particularly
fish, whose lymphatic vessels either have no valves, or the
valves readily give way, so that I have repeatedly pushed in-
jections from the thoracic duct into the lymphatics of their
stomachs, as I have also done into the lymphatics of the other
viscera contained in the cavity of their abdomen; as will be
more particularly mentioned hereafter.

The thoracic duct, which receives all the vessels that we
have yet described, differs in its size in different subjects, but

1 Dr. Meckel.

LYMPHATIC SYSTEM. 135

is always smaller in its middle than at its beginning, as is seen
in Plate II. Sometimes its lower part at m is still larger in
proportion than is there represented, and that enlargement has
been called the receptaculum chyli, and is considerable in some
quadrupeds, in turtle, and in fish : but many anatomists have
denied that there is any part of the thoracic duct in the human
subject; that deserves the name of receptaculum, and my ex-
perience makes me subscribe to their opinion, as I have never
seen anything like a pyriform bag, as it has been described,
but merely an enlargement not unlike a varix, and that only
in few subjects : for commonly it appears, as in this plate, only
a little larger than at its middle. This lower extremity of the
thoracic duct is formed by the union of two, three, or four
very large trunks of lymphatic vessels : these large vessels unite
so as to form the duct about the lower part of the first, or the
upper part of the second vertebra lumborum, reckoning down-
wards.

These large lymphatic trunks which form the thoracic duct
are spread out upon the spine, those of the right side lying
below the right cms diaphragrnatis, and 'those of the left pass-
ing between the aorta and the spine; whilst the thoracic duct
itself lies on the right side of the aorta, between that artery
and the right cms diaphragmatis, and behind the emulgent
artery of the right side, as is seen in Plate II at n. From
this part it passes upwards, being at first covered by the cms
diaphragmatis, and afterwards appears at o in the thorax,
upon the spine between the aorta and the vena azygos. In the
thorax it receives some lymphatics from the intercostal spaces ;
a few of which are seen at p and afterwards it receives vessels
from the lungs.

The lymphatics of the lungs are in two sets, one of which
passes on the posterior part of each lobe by its root, into the
thoracic duct near the middle of the thorax; and another set
passes from the fore part of each lobe up towards the jugular
and subclavian veins. Some of the lymphatics on the posterior
part of the left lobe pass under the aorta to get to the thoracic
duct.

At the root of the lungs, where the large blood-vessels enter,
are many glands called bronchial, they are generally of a black-
ish colour in the human subject, and have been suspected to

136 LYMPHATIC SYSTEM.

secrete the mucus which is spit up from the trachea; but I
have more than once distinctly filled them with mercury by
injecting the lymphatic vessels of the lungs, and therefore it
is evident that they are not mucous but lymphatic glands.

The lymphatic vessels from the anterior part of the left lobe
of the lungs pass into the angle between the jugular and sub-
clavian vein of the same side, joining the thoracic duct at its
termination, whilst those from the fore part of the right lobe
do not communicate with the thoracic duct, but pass into the
angle between the right jugular and the right subclavian vein.
These lymphatics from the anterior parts of the lungs are pro-
bably accompanied by those of the heart, which are represented
by the accurate Nuck in his ' Adenographia, ' fig. XLI.

The thoracic duct, after receiving the vessels before men-
tioned, passes behind the ascending aorta, see Plate III, and
goes to the left side, terminating in the angle between the
jugular and the subclavian vein. But, just before its termina-
tion, it generally goes higher up than the angle, and then
bends down towards it, as is seen, Plate III, b, c. Sometimes
there are two thoracic ducts instead of one, but this rarely
occurs in the human subject, but it is not unfrequent for the
duct to split near the upper part of the thorax, and the two
branches, after spreading out from one another, commonly
unite again at their termination in the angle between the left
jugular and subclavian veins. I never saw any part of the
thoracic duct terminate in the right subclavian of the human
body, though such a circumstance has been observed by others.1
But I have now by me a preparation where the "duct splits at
the upper part of the thorax into two branches, one of which
enters the angle between the jugular and subclavian of the left
side, and the other opens into the left subclavian vein, about
half an inch on the outside of that angle.

In the description of the lymphatic vessels which lie near
the spine, I have mentioned only a few glands, and in Plate II,
i,i, i where those vessels are exhibited no glands are represented.
This I at first considered as an imperfection in the preparation,
and had intended to make a drawing from another, but there
are two reasons which have induced me to lay the present one
before the reader. First, the lymphatic glands are not con-
1 Dr. Meckel, Epist. ad Hallerum, p. 30.

LYMPHATIC SYSTEM. 137

stant, either in number or situation ; and therefore the describ-
ing them particularly in any one subject is less necessary, since
we cannot be sure of finding them exactly the same in any
other. Secondly, the injecting the lymphatic vessels from the
groin to the neck, without filling one lymphatic gland, proves
a fact which is contradictory to the received opinion concern-
ing those vessels, viz that they always pass through glands in
their way to the blood-vessels, so that if these glands were ob-
structed, a dropsy must be an inevitable consequence, which is
not strictly true when we speak of the lymphatic vessels in the
abdomen, where, I find, besides the vessels which go into the
glands, there are generally some which escape them. The
same is true with respect to the lacteals, so that an obstruction
of the mesenteric glands may not always produce a marasmus,
as a part of the chyle may pass the glands and get into the
thoracic duct.

But although no lymphatic glands are represented in Plate II,
it may be necessary to mention where they are commonly seen.

The mesentery of the human subject is well known to con-
tain a considerable number of them ; they are likewise found
in the mesocolon where the lymphatics of the large intestines
pass through them. The stomach has also several glands which
belong to its lymphatic vessels, and lie near the arteria coro-
naria, and the arteria gastrica dextra. There are likewise a few
upon the omentum in some subjects, and there are also many
glands by the sides of the pancreas, particularly near the lesser
lobe of that viscus, close to the duodenum.

Besides these glands which belong to the intestinal tube,
there are many more in the cavity of the abdomen, and a few
in the cavity of the pelvis, which belong to the lymphatic ves-
sels of the other organs.

There is commonly a pretty considerable"gland seen just on
the inside of the edge of the tendon of the external oblique
muscle, called Poupart's ligament, on the outside of the iliac
artery ; and there are others near that artery, where it lies upon
the psoas muscle. There are likewise commonly one or two
near the internal iliac artery in the cavity of the pelvis, and
there is a considerable number generally met with by the sides,
and upon the lumbar vertebrae. In the subject from which I
took Plate II, the spaces i, i, i, were occupied by such glands,

138 LYMPHATIC SYSTEM.

which were not injected, and therefore are not represented in
that plate.

Near the spleen, liver, kidneys, and renal capsules, there are
also lymphatic glands which belong to the lymphatic vessels of
these organs.

There are likewise lymphatic glands sometimes observed by
the sides of the thoracic duct, particularly about the middle of
the thorax, which glands belong principally to the vessels of
the lungs.

There are also many lymphatic glands (called bronchial)
near the root of the lungs ; these glands are placed upon the
lymphatic vessels, just where they quit the lungs. But no
lymphatic glands have yet been observed in the substance of
the lungs, and the tubercles (LXV) which some suspect to be
obstructed lymphatic glands, seem to have a different origin.
There are likewise some glands seen on the lymphatic vessels
which lie near the subclavian veins at the upper part of the
thorax, and which belong to the fore part of the lungs.

Besides these there are some lymphatic glands upon the
aorta near the oesophagus, and there are also others occasionally
met with in the intercostal spaces, and there are generally two
or three contiguous to the thoracic duct at the lower part of
the neck and upper part of the thorax, near the termination of
that duct, in the angle between the left jugular and the left sub-
clavian vein.

Having thus traced the lymphatic system in all parts of the
body that are below the termination of the thoracic duct, I
shall next examine that part of it which lies upon the head,
neck, and upper extremities, where the tracing it is attended
with greater difficulties.

By the side of each internal jugular vein is a large lymphatic
vessel, which is the trunk of those of one side -of the head and
neck ; that of the right side is seen Plate III /. There are
likewise smaller lymphatics which are seen near the branches
of the external carotid artery. There are also lymphatic glands

(LXV.) In pulmonary consumption, the tubercle may be situated
either within the air-cells or in the filamentous tissue between and on
the outside of them. See my observations in Professor Wagner's Phy-
siology, translated by Dr. Willis, p. 360, fig. CLXXV; and in the Edin.
Med. and Surg. Journ. Ix, 161.

LYMPHATIC SYSTEM. 139

by the sides of the parotid and maxillary glands, and by the
sides of the large artery where it lies upon the chin, and by
the side of the occipital artery ; and I have seen one upon the
root of the mastoid process of the temporal bone. Those glands,
which accompany the lower part of the artery that runs upon
the face, are sometimes swelled in consequence of absorption
from the lips and the parts adjacent, and also from gum-boils;
and those which accompany the occipital artery are frequently
enlarged in consequence of the absorption of matter from
wounds of the scalp ; from which facts it is evident that the
external parts of the head are supplied with lymphatic vessels.
In quadrupeds I have distinctly seen those vessels, particularly
in a dog and in an ass, by passing a ligature round the large
blood-vessels of their necks immediately after killing those
animals. These experiments I made with a view to determine
whether the brain had lymphatic vessels, but I never yet have
been able to see any on that organ ; neither when I tied up
the lymphatics on the necks of those animals, and thereby
stopped the course of the lymph ; nor when I dissected the
human brain, which I have carefully done several times with
the view to discover those vessels, and have particularly sought
for them in the plexus choroides where they have been sus-
pected to be seen, and near the glandula pituitaria which is
supposed by some to be a lymphatic gland, but improperly,
since neither that gland nor the glandula pinealis agrees with
the lymphatic glands, as I shall show in the Third Part of these
Inquiries.

But although lymphatic vessels have not yet been demon-
strated in the brain, it is probable, from analogy, that this
organ is not destitute of them ; and the following case affords
an argument in favour of absorption being carried on here by
lymphatics, as well as on other parts of the body.

J. H., a young man of twenty-five years of age, by trade a
silk dyer, and whose father at that time laboured under a third
attack of madness, consulted me about a glandular tumour upon
the left side of his neck, of which he gave the following ac-
count : that for some time he had been troubled with an erup-
tion which had gone off and returned repeatedly ; that a week
after its last disappearance, he was seized with a fixed pain in
his forehead, for which he was bled ; that one day whilst at

140 LYMPHATIC SYSTEM.

work, after this pain had continued a fortnight, he felt a weak-
ness in his left arm, and the brush with which he was working
fell out of his hand, but he had no weakness in his right arm,
nor in his legs. That this weakness returned two or three
times a day for nine days ; and was rather relieved by putting
his hands into warm water. About three days after he was
first attacked with this weakness, a tumour appeared on the left
side of his neck, just below the ear ; when I first saw him this
tumour had continued eleven days. It seemed to be an en-
larged lymphatic gland, was then hard, but afterwards gradually
came to suppuration, and at the end of six weeks it burst and
discharged a yellow curdled matter. He adds at the same
time that he was attacked with the weakness, he had a falter-
ing in his speech, and slight convulsions in his lips.

Now as in this case there seemed to be a compression of the
brain, which was removed when the glands swelled, is it not
probable that the cause of the compression had been some ex-
travasated fluid, which afterwards being absorbed, occasioned
the tumour and suppuration of the lymphatic gland ? and there-
fore is it not a presumption that absorption is here likewise
carried on by lymphatic vessels ?

The small lymphatics which accompany the branches of the
external carotid artery unite upon the neck, and form a large
trunk which accompanies the internal jugular vein, passing
through some lymphatic glands, near the termination of this
trunk in the angle between the jugular and subclavian veins ;
there are likewise some glands on the outside of this angle,
which seem to belong to the lymphatics from the back of the
neck, and of the shoulder.

The thyroid gland has many lymphatic vessels, which
can sometimes be inflated by blowing air into the cells of the
gland : these vessels pass on each side of the trachea, one part
going into the angle of the right subclavian and jugular, and
the other joining the thoracic duct upon the left side. They
are seen in Plate III at/.

So much for the lymphatics of the head and neck ; I shall
next proceed to describe those which belong to the arms.

Each arm, like the leg, has two sets of lymphatic vessels,
one which lies immediately under the integuments, and belongs
to the skin and cellular membrane connecting it to the mus-

LYMPHATIC SYSTEM. 141

cles ; and the other which accompanies the large arteries, and
belongs to the parts deeper seated.

The superficial set of lymphatic vessels may be discovered in
emaciated dropsical subjects, by a careful dissection on the fore
and back part of the arm, where I have fixed pipes into them
and have injected them with mercury. In Plate IV, fig. 1, they
are seen running on the back part of the fore arm as at 0,0,0,
most of them passing on its outside, and twisting to the fore
part, near the head of the radius, as at b. But there is one
vessel in this preparation which passes towards the inside,
under the inner condyle of the os humeri at c, and sends a
branch amongst the muscles, which branch perforates the in-
terosseous ligament, getting between the radius and ulna to the
fore part, where it joins a deep-seated one that had accompanied
the radial artery.

In Plate IV, fig. 2, the lymphatic vessels are seen on the fore
part of the upper extremity; those superficial branches which
passed on the outside of the back to the fore arm appearing now
on the fore part at b and ascending under the skin that covers
the supinator longus and the biceps, they enter some glands in
the axilla at /, /, whilst that vessel which passes on the in-
side of the back of the fore arm under the internal condyle,
appears on the fore part at c, and just above the condyle
enters a gland d, and then passes up on the inside of the arm,
communicating with a lymphatic from the fore part of the
wrist, and passing to the axillary glands.

A superficial lymphatic vessel is seen under the skin, on the
fore part of this extremity just above the wrist ; a pipe was in-
troduced at 0, and the lymphatic thereby injected with mercury.
This vessel passes under the integuments over all the muscles,
and joins the lymphatic from the back part of the fore arm at e,
and there forms a plexus which passes under the integuments,
on the inside of the arm to the axillary glands at /.

Besides these superficial lymphatic vessels upon the upper ex-
tremity, I have traced a deeper-seated one near the radial artery,
and have injected it from a pipe fixed at g. This lymphatic
vessel accompanies the radial artery, and passes, first under the
inter osseous, and then under the ulnar artery, which in this sub-
ject runs over the muscles. Near the part where the lymphatic
passes under the interosseous artery, it receives the branch (as
formerly mentioned) from the back of the fore arm. After pass-

142 LYMPHATIC SYSTEM.

ing under these arteries, this lymphatic appears on the inside
of the brachial artery at i, where it is deep seated, ascending
close to that artery, and near the middle of the arm, passes
through the two glands k k, after which it appears consider-
ably enlarged, and goes under one of the arteriae anastomaticse
at /, my and then ascends to the lymphatic glands in the axilla.

But these vessels, though filled more successfully in this ex-
tremity than in any other that I ever injected, are only a part
of the larger lymphatic vessels of the arm, as there are probably
some accompanying the ulnar and interosseous arteries, although
not here injected : and they should moreover be considered as
only trunks of the lymphatics, since it is probable that every
(even the smallest) part of this, as well as all other parts of the
body, has one of these vessels adapted to absorption (LXV*); that
this is the case seems to be proved by the experiments made
with the variolous matter, for at what part soever of the arm that
matter is inserted, the lymphatic vessels take it up and carry it
into the body, as can be traced by its inflaming the conglobate
glands through which these vessels pass.

In Plate III the termination of all these lymphatic vessels
is exhibited. Two of the trunks of those of the left arm are
seen at d, d, which pass under the clavicle, whose cut end is
seen at D, and under the subclavian vein s, where, having
joined, they form the large trunk e, which appears just above
the left subclavian vein, and joins the extremity of the thoracic
duct at its entrance into the angle between that vein and the
jugular. That these lymphatics commonly join the thoracic
duct, as is here described, I am persuaded from having seen it
distinctly in three subjects. But that they may, in some in-
stances, open into the subclavian vein before they reach the
angle, I think is likewise probable from having observed it in the
case above mentioned; in which case, the thoracic duct having
split into two trunks, one of these trunks, instead of entering
into the angle between the veins, opened into the subclavian
itself, about an inch from the angle ; but this circumstance I
should consider as only an exception from a general rule.

(LXV*.) It is now generally admitted that absorption may take place
independently of lymphatic vessels ; see Note LXXXII. In those parts
into which blood-vessels cannot be traced, lymphatics have not been
discovered.

LYMPHATIC SYSTEM. 143

The thoracic duct is not only joined by this trunk of the
lymphatics of the left arm, but also by the lymphatic vessels of
the left side of the thyroid gland, which appear at /, and by
the trunk of the lymphatics of the left side of the head and
neck, and also by those from the fore part of the lungs of the
same side ; but neither of these appear in this plate.

The lymphatic vessels of the right side I have repeatedly
traced with great care, particularly from their having been
suspected to terminate in the subclavian vein, without reaching
the angle between it and the jugular ; but I have always dis-
tinctly seen them go precisely into the angle, not only in the
subject from which this plate was made, and which I now have
by me, but also in three others. When therefore these lym-
phatics are seen to enter the subclavian vein at any other part,
I should consider it as only an accidental variety, like the double
termination of the thoracic duct formerly mentioned.

These lymphatic vessels of the right side form four consi-
derable trunks, which join near their termination. These
trunks are — first, one from the upper extremity, which appears
at k, Plate III, lying above the clavicle between the subcla-
vian artery and vein ; this trunk is formed by the lymphatic
g, g, which comes up with the brachial artery, and the plexus
h, which likewise belongs to the arm, and passes under the
subclavian vein. Secondly, the trunk of the lymphatic vessels
of the right side of the head and neck which passes down on
the outside of the jugular vein, as is seen at /. Thirdly, a
lymphatic from the thyroid gland, which lymphatic is seen at
m, passing under the right jugular vein to get to the others.
Fourthly, the trunk of the lymphatics from the fore part of the
lungs of the right side, which trunk I have distinctly traced
under the subclavian vein to its termination, in common with
the others, at the angle between the jugular vein and the sub-
clavian.

To finish this description, I shall observe that it is the more
necessary to understand the exact termination of these lym-
phatics of the right side, in order to explain how tumours
about this place, by compressing those vessels, occasion oedema-
tous swellings of the parts from which the vessels come,
without affecting the other parts of the body.

CHAPTER IV.

A DESCRIPTION OF THE LYMPHATIC SYSTEM IN BIRDS.1

THIS system consists in birds, as it does in the human sub-
ject, of three parts, viz. the lacteals, the lymphatic vessels, and
their common trunk the thoracic duct.

The lacteals indeed, in the strictest sense, are, in birds, the
lymphatics of the intestines (see Note LIX), and like the other
lymphatics carry only a transparent lymph. And instead of one
thoracic duct there are two which go to the two jugular veins.
In these circumstances it would seem, that birds differ from the
human subject, so far at least as I may judge from the dissec-
tion of a goose, which was the bird I chose as most proper for
this inquiry, and from which I took the following descrip-
tion, after previously injecting its lymphatic system with quick-
silver.

The lacteals run from the intestines upon the mesenteric
vessels. Those of the duodenum pass by the side of the pan-
creas, and probably receive its lymphatics : afterwards they get
upon the cceliac artery, of which the superior mesenteric is a
branch. Whilst they are upon this artery they are joined by
the lymphatics from the liver; here they form a plexus, which
surrounds the cceliac artery ; at this part they receive a lym-
phatic from the gizzard ; and a little farther, another from the
lower or glandular part of the oesophagus. Having now got to
the root of the coeliac artery, they are joined by the lymphatics
from the renal glands, or renal capsules; and near the
same part, by the lacteals from the other small intestines,
which vessels accompany the lower mesenteric artery. These
last-mentioned lacteals, before they join those from the duode-
num, receive from the rectum a lymphatic which runs with

1 This description has already been printed in the Philosophical Transactions, vol.
Iviii, where I have added a plate, which was thought unnecessary in this hook.

LYMPHATIC SYSTEM. 145

the blood-vessels of that gut. Into this lymphatic some small
branches from the kidneys seem to enter, which coming from
those glands upon the mesentery of the rectum, at last open
into its lymphatics. At the root of the coeliac artery, the
lymphatics of the lower extremities probably join those from
the intestines. The former I have not yet traced to their ter-
mination, though I have distinctly seen them on the blood-
vessels of the thigh; and in one subject, which I injected, some
vessels were filled, contrary to the course of the lymph, from the
network of lymphatics near the root of the coeliac artery ; these
vessels ran behind the cava, down upon the aorta, near to the
origin of the crural arteries, and I presume they were the trunks
of those lymphatic branches which I had seen in the thigh. At
the root of the coeliac artery, and upon the contiguous part of
the aorta, a network is formed by the lacteals and lymphatics
above described. This network consists of three or four trans-
verse branches, which make a communication between those
which are lateral. In the subject from which this description
was taken there were four. From this network arise the two
thoracic ducts ; of which one lies on each side of the spine,
and runs upon the lungs obliquely up towards the jugular vein,
into which it opens, not indeed into the angle between the
jugular and subclavian vein, as in the human subject, but
into the inside of the jugular vein, nearly opposite to the angle.
The thoracic duct of the left side is joined by a large lymphatic,
which runs upon the oesophagus, and can be traced as far as
the lower or glandular part of that canal ; from which part,
or from the gizzard, this lymphatic seems to issue. The thoracic
ducts are joined by the lymphatics of the neck (and probably by
those of the wings) just where they open into the jugular veins.
The lymphatics of the neck generally consist of two pretty
large branches, on each side of the neck, accompanying the
blood-vessels.1 Those two branches join near the lower part
of the neck ; and the trunk is, in general, as small, if not
smaller, than either of, the branches. This trunk runs close
to the jugular vein, gets on its inside, and then opens into a
lymphatic gland. From the opposite side of this gland, a
lymphatic comes out, which pours the lymph into the jugular

1 These lymphatics in the necks of fowls were first discovered by Mr. John Hunter.

10

146 LYMPHATIC SYSTEM.

vein. On the left side, the whole of this lymphatic joins the
thoracic duct of the same side, but, on the right, one part of it
goes into the inside of the jugular vein a little below the angle
which that vein makes with the subclavian.

This system in birds, differs most from that in quadrupeds
in the chyle being transparent and colourless (LXVT), and in
there being no visible lymphatic glands, neither in the course
of the lacteals, nor in that of the lymphatics of the abdomen,
nor near the thoracic ducts.

For the sake of those who may incline to prosecute this in-
quiry farther, I shall relate the method by which these vessels
may be demonstrated ; and that is, having chosen a young and
very lean goose, and fixed it upon a table, let the abdomen be
opened whilst it is yet alive, and a ligature be passed round
its mesenteric vessels, as near the root of the mesentery as
possible. The lacteals will begin to appear near the ligature
in a few minutes after it is made, especially if the bird has
been well fed three or four hours before the experiment. The
lymphatics in the neck may be shown in the same manner,
that is, by making a ligature on the jugular vein at the lower
part of the neck ; and to be more certain of including the
lymphatics which are near it, we must take care not to pass
the needle too close to that vein.

(LXVI.) See Note LIX.

CHAPTER V.

A DESCRIPTION OP THE LYMPHATIC SYSTEM IN ONE OF THE
ANIMALS CALLED AMPHIBIOUS, VIZ. THE TURTLE.

THIS system. in a turtle, like that in birds, consists of the
lacteals, the lymphatics, and their common trunks, the thoracic
ducts. It agrees likewise with that in birds, in not having
any lymphatic glands either on the mesentery or near the tho-
racic ducts ; but differs from that in birds in not having any
glands upon the larger lymphatics of the neck ; at least I am
inclined to believe so, from not having seen any of these glands
in the dissection of one animal of this species in which I looked
for them. It likewise differs from that in birds in another cir-
cumstance, to be taken notice of hereafter. Whether it agrees
with the same system in birds, in the transparency and want
of colour in the chyle, I cannot take upon me to determine, as
I did not see any of that fluid in this subject.1

The following description I took from the animal, after I
had injected the larger branches of this system with a coloured
wax, and the smaller with quicksilver. To avoid my being
misunderstood, when I speak of the situation of the different
parts, I shall mention, once for all, that the description was
taken from the subject as it lay upon its back ; those parts
being called highest which were nearest the head, those lowest
which were nearest the tail, those posterior which were nearest
the back, and those anterior nearest the belly.3

The lacteals accompany the blood-vessels upon the mesentery,
running by their sides, and communicate frequently across
those vessels. Near the root of the mesentery they anasto-
mose, so as to form a network, from which several large

1 In a crocodile, an animal of the same class, the chyle is white.

2 The animal from which I took this description was pretty large, measuring from
the lower to the upper part of the shell two feet seven inches, and two feet two
inches from side to side.

148 LYMPHATIC SYSTEM.

branches go into some considerable lymphatics lying on the
left side of the spine. These last can be traced downwards
almost to the anus, and belong to the parts situated below the
mesentery, and particularly to the kidneys. At the root of
the mesentery, on the left side of the spine, the lymphatics of
the spleen join the lacteal s, and immediately above this union
a sort of plexus or network is formed, which lies upon the
right aorta (for there are two aortse in this animal). From this
plexus a large branch arises, which passes behind the right
aorta to the left side, and gets before the left aorta, where it
assists in forming a very large receptaculum which lies upon
that artery. From this receptaculum arise the thoracic ducts.
From its right side goes one trunk, which is joined by that
large branch which came from the plexus to the left side of
the right aorta, and then passes over the spine. This trunk is
the thoracic duct of the right side; for, having got to the right
side of the spine, it runs upwards, on the inside of the right
aorta, towards the right subclavian vein. And when it has
advanced a little above the lungs, or within three or four inches
of the subclavian vein, it divides into branches, which, near
the same place, are joined by a large branch that comes up on
the outside of the aorta. From this part upwards those ves-
sels divide and subdivide, and are afterwards joined by the
lymphatics of the neck, which likewise form branches before
they join those from below ; so that between the thoracic duct
and the lymphatics of the same side of the neck a very intri-
cate network is made. From this network a branch goes into
the angle between the jugular vein and the lower part or trunk
of the subclavian : this branch, therefore, lies on the inside of
the jugular, whilst another gets to the outside of that vein,
and seems to open into it a little above the angle between that
vein and the subclavian. I say seems to open, for the injec-
tion had not succeeded at this part so as to enable me to de-
termine whether the last-mentioned branch did enter or not.
Into the above-mentioned receptaculum the lymphatics of the
stomach and duodenum likewise enter. Those of the duo-
denum run by the side of the pancreas, and probably receive its
lymphatics, and a part of those of the liver. The lymphatics
of the stomach and duodenum have very numerous anasto-
moses, and form a beautiful network on the artery which they

LYMPHATIC SYSTEM. 149

accompany. From this receptaculum likewise (besides the
trunk already mentioned which goes to the right side) arise two
other trunks pretty equal in size, one of which runs upon the
left side and the other upon the right side of the left aorta, till
they come within two or three inches of the left subclavian vein,
where they join behind the aorta, and form a number of branches,
which are afterwards joined by the lymphatics of the left side of
the neck, so that here a network or plexus is formed, as upon the
right side. From this plexus a branch issues, which opens
into the angle between the jugular and the lower part or trunk
of the subclavian vein. In these networks, formed by the
lymphatics near their terminations in the veins, this system in
the turtle likewise differs remarkably from that in birds.

So much for the general description of the lymphatic system
in this animal. I shall next add what I have remarked as to
the more minute distribution of its lacteals. In the first
place, it may be observed that what knowledge we have of the
minute distribution of those vessels in quadrupeds has been
acquired from examining them when filled with their natural
fluid, the chyle; for the valves with which those vessels abound
prevent our injecting their smaller branches, as we do those of
the arteries and veins of the intestines. But in this animal I
have been so fortunate as to force the valves, and to inject the
lacteals from their trunks to their branches, so as to fill them
all around with quicksilver, in several parts of the intestine.
In these experiments I observed that the quicksilver was often
stopped by the valves, where the lacteals run upon the mesen-
tery, or where they are just leaving the intestine ; but when
those valves were forced, and the quicksilver had once got
upon the surface of the gut, it generally ran forward without
seeming to meet with any obstacle. The lacteals anastomose
upon the intestines, so that the quicksilver, which has got
upon them by one vessel, in general, returns by another, at
some distance. The larger lacteals, which run upon the intes-
tines, accompany the blood-vessels; but the smaller lacteals
neither accompany those vessels nor pass in the same direction,
but run longitudinally upon the gut, and dip down through the
muscular coat into the cellular or nervous, as it has been called,
which in this animal is very thin in comparison to what it is in
the human subject. So far I have traced those vessels to my satis-

150 LYMPHATIC SYSTEM.

faction ; but what becomes of them after they have got to the
cellular coat is not so easy to determine : in five or six dif-
ferent experiments which I have made, the mercury passed
from the lacteals into the cells between the muscular coat and
the internal, and spread from cell to cell very uniformly over a
great part of the intestine, although but little force had been
used, and although there was nothing like extravasation in any
other part of the intestine. Upon inverting the intestine,
after thus filling its lacteals, the mercury, on being pressed,
was in many parts driven into small vessels upon the internal
coat, or villous, as it is called. From whence it would seem
that this cellular network was a part of the lymphatic system
in this animal. It might indeed be supposed to be mere ex-
travasation, but that it is rather a part of the lymphatic
system appears from the following considerations : first, from
the regularity in the size of the cells ; secondly, from the little
force used in the experiment, and from there being nothing
like this appearance in the cellular membrane between the
peritoneal and the muscular coat, where extravasations were as
likely to happen ; thirdly, from my having been able, after in-
verting the intestine, to press the quicksilver from the cells
into the very small vessels upon the internal coat. But I
must confess these facts would not be sufficient to determine
whether these cells were or were not a part of the system, did
not the analogy of the same part in fish clearly prove it. For
in the cod, instead of the cellular network, as in the turtle,
there is a network of vessels (of which a description shall be
given in the next chapter), so that I have now no doubt but
that those cells are parts of the lymphatic system, and that the
small absorbent vessels of the internal coat pour their fluid
into this network, from which it is conveyed by the larger
lacteals.

CHAPTER VI.

THE METHOD OF DISCOVERING THE LYMPHATICS IN TURTLE AND
IN FISH, TOGETHER WITH A DESCRIPTION OF THOSE VESSELS
IN A HADDOCK.

IN the foregoing chapter on the lymphatic system in a
turtle, I have made no mention of the manner of discovering
those vessels, because there is no difficulty in doing it ; for in
that animal the mesentery being very thin and transparent,
and the lacteals pretty large, they are more readily observed
than in any other animal ; thence it happened that I saw those
vessels in a turtle so long ago as 1763, which was before I dis-
covered them in birds and fish.

But although it was an easy matter to see those vessels in
the turtle, yet it was far from being so in birds and fish ; as
the reader will readily believe, from their having been so often
sought for in vain by so many eminent anatomists (LXVI*), par-
ticularly of this age. I may add, that the discovery in birds did
not give me so much trouble as that in fish, though now, since I
have once seen them, I can more readily find them in fish than
in birds or quadrupeds. After seeing them in birds, and in
one of the amphibia, I was very desirous of determining whether
fish were or were not provided with those vessels. This I en-
deavoured to do in the same way that I had found them in
birds, that is, by tying up the mesenteries of live fish ; and for
this purpose I went frequently to the markets, and examined
several small ones. I likewise dissected some larger when
dead, but in vain. I next went to Brighthelmstone, where I
found kingston, or monk-fish, a species of skate. These being
very large, and having a lean mesentery, seemed well fitted to
my purpose, I opened two of them alive, tied up their mesen-
teric vessels, and put them again into the salt water ; and

(LXVI*.) Thomas Bartholin, referred to in the Introduction, saw lac-
teal vessels in a fish.

152 LYMPHATIC SYSTEM.

though one of them lived an hour, I could not observe any
lacteals either upon its intestine or its mesentery. After this
I repeatedly examined the intestines and mesenteries of common
skate and cod, and at last was so fortunate as to discover the
lacteals, and get a pipe into one of those vessels on the mesen-
tery of each of these fish ; and, injecting by this pipe, I found
where the larger vessels lay ; after which there was but little
difficulty in tracing the whole system. I have now seen those
vessels in a variety of fish, and shall give a description of them
from a haddock. I shall proceed exactly in the order which
I have found most convenient for tracing out the whole sys-
tem for demonstration, beginning with one of its branches,
which, as lying nearest the surface, must, of course, be divided
before the other parts can be exposed to view. The account
being taken from the fish as it lay on its back, those parts are
called superior which are nearest the head ; those inferior which
are towards the tail ; those posterior which are towards the
back ; and those anterior which are towards the belly.

On the belly of the fish, exactly in the middle line, is a
lymphatic, which runs from the anus upwards ; this lymphatic
belongs not only to the parietes of the belly, but to the fin
below the anus. It runs up towards the head, passes between
the two pectoral fins, and, having got above them, it receives
their lymphatics. It then goes under the symphysis of the
two bones which form the thorax, where it opens into a net-
work of very large lymphatics, which lies close to the pericar-
dium, and almost entirely surrounds the heart. This network,
besides that part of it behind the heart, has a large lymphatic
on each side, which runs upon the bone of the thorax back-
wards, and when it has got as far as the middle of that bone,
it sends off a large branch from its inside to join the thoracic
duct. After detaching this branch it is joined by the lymphatics
of the thoracic fins and soon after by a lymphatic which runs
upon the side of the fish. This last-mentioned vessel consists of a
trunk running on the side just opposite to the ribs, and from
this trunk proceed branches on each side immediately under the
skin ; so that it has a beautiful penniform appearance. Besides
these branches, there is another set, deeper seated, which ac-
companies the ribs. After the large lymphatic has been joined
by the above-mentioned vessels, it receives the lymphatics from

LYMPHATIC SYSTEM. 153

the posterior extremities of the gills, and having now got as far
back as the orbit, it next receives lymphatic vessels from that
cavity ; but these vessels do not belong merely to the orbit ;
for one of them comes from .the nose, and another from the
upper part of the mouth. A little below the orbit another
network appears, consisting, in part, of. the vessels above de-
scribed and of the thoracic duct. This network is very com-
plex ; some of its vessels lie on each side of the muscles be-
longing to the gills, and from its internal part a vessel goes
into the jugular vein, by which vessel the whole system is ter-
minated. The large lymphatic above mentioned, which lies
upon the bone of the thorax, has likewise a process running
towards the upper part of the kidney, and receives some of
the lymphatics of that organ.

The lacteals run on each side of the mesenteric arteries, anas-
tomosing frequently *across those vessels. The receptaculum, into
which they enter, is very large in proportion to them, and con-
sists, at its lower part, of two branches, of which one lies be-
tween the duodenum and stomach, and runs a little way upon
the pancreas, receiving the lymphatics of the liver, pancreas,
those of the lower part of the stomach, and the lacteals from
the greatest part of the small intestines. The other branch of
the receptaculum receives the lymphatics from the rectum, and
the lacteals from the greatest part of the small intestines. The
receptaculum formed by these two branches lies on the right
side of the upper part of the stomach (or the lower part of the
oesophagus), and is joined by some lymphatics from that part,
and also by some small vessels from the sound and from the
gall-bladder, which in this fish adheres to the receptaculum.
The thoracic duct takes its rise from the receptaculum, and lies
on the right side of the oesophagus, receiving lymphatics from
that part ; and running up a little way (viz. about half an inch
in this fish) it divides into two branches or ducts, one of which
passes under the oesophagus to the left side, and the other goes
straight up on the right side, passes by the upper part of the
kidney, from which it receives some small branches, and soon
after is joined by a branch from the large lymphatic that lies
above the bone of the thorax, as formerly mentioned. It like-
wise, near this part, sends a branch to join the duct of the op-
posite side, and then a little higher is joined by those large

154 LYMPHATIC SYSTEM.

lymphatics which make a network behind the heart, as is
above described. These last mentioned vessels receive the lym-
phatics from the anterior or superior part of the gills, and
from the fauces. The thoracic duct, after being joined by
these vessels, communicates with that network near the orbit ;
where its lymph is mixed with that of the lymphatics from the
posterior part of the gills, from the superior fins, belly, &c., and
then from this network a vessel gojes into the jugular vein,
just below the orbit. This last vessel, which I call the termi-
nation of the whole system, is very small in proportion to the
network from which it rises ; and indeed the lymphatics at this
part are so large as to exceed by far the size of the sangui-
ferous vessels.

The thoracic duct of the left side, having passed under
the oesophagus from the right, runs on the inside of the
vena cava of the left side, receives a branch from its fellow of
the opposite side, and joins the large lymphatics which lie on the
left of the pericardium, and a part of those which lie behind
the heart, and afterwards makes, together with the lymphatics
from the gills, upper 'fins, and side of the fish, a network,
from which a vessel passes into the jugular vein of this side.
In a word, the lymphatics of the left side agree exactly with
those of the right, as above described.

Besides these vessels, there is yet another part of the sys-
tem which is deeper seated, lying between the roots of the
spinal processes of the back-bone ; this part consists of a large
trunk, that begins from the lower part of the fish near the tail,
and as it ascends receives branches from the dorsal fins, and
from the adjacent parts of the body. It goes up near to the
head, and sends a branch to each thoracic duct, near the part
where these ducts come off from their common trunk.

This description, though taken from a haddock, agrees, I
believe, pretty exactly with the distribution of those vessels in
the cod, whiting, and perhaps all other fish of the same shape.

To this general description I shall add what I have observed
of the more striking peculiarities of this system in fish.

In the first place, those vessels are remarkable in not having
any lymphatic glands, that I can discover, in any part of their
course. In this they agree with the turtle, but differ from
birds, which have lymphatic glands on the vessels of their
necks.

LYMPHATIC SYSTEM. 155

Secondly, these vessels in fish either have no valves, or the
valves readily give way, for it is an easy matter to fill them
contrary to the- course of the lymph. When I first observed
this circumstance, I imagined that by injecting minutely those
vessels, I might discover their very beginnings, and that I might
also be enabled to determine whether such parts as the brain,
eye, &c., of which the lymphatics have not been yet seen in any
animal, have or have not such vessels. What success I have
had in these experiments will be related in a future publica-
tion (LXVII).

Thirdly, the lacteals in the cod (and I presume in most
other fish) are remarkable for having a beautiful network of
vessels between the muscular and villous coat of the intestines.1
This network may be filled from the lacteals on the mesentery
with the least force imaginable. If mercury be injected into
this network at one part, it spreads over the intestine, the
communications in the network being very numerous ; if the
intestine b'e inverted, and the mercury squeezed, it is easily
driven into the small vessels of the villi of the internal coat.2
From these vessels the mercury can be forced into the cavity
of the intestine ; but not so easily as to make it clear whether
they have or have not a valve at their beginning. In these
circumstances there is a strong analogy between fish and the
turtle ; but in fish it is more evident that there can be no de-
ception as to the network between the muscular and the in-
ternal coat ; for in them it is made up of cylindrical vessels,
and is not cellular as in the turtle, and therefore not in the
least like an extravasation ; and in fish the vessels on the in-
ternal coat are larger than in the turtle.

Fourthly, this system agrees with that of the turtle, in hav-
ing a very large receptaculum, and in having the network of
large vessels near its termination in the sanguiferous system ;

1 I have seen this network in the turbot, plaice, and cod.

2 If instead of mercury a thin size be used, as an injection it will run with the
same facility into the lacteals upon the villi, as it would do into their arteries and
veins, when thrown in by a pipe fixed in those vessels.

(LXVII.) Mr. Hewson died May 1, 1774, the same year that this
second part of his Experimental Inquiries was published. Dr. James
Heudya mentions Mr. Falconar's supposition, that he had injected
lymphatic vessels in the brain of the cod-fish.

a On Glandular Secretion, p. 7, 8vo, Lond. 1775.

156 LYMPHATIC SYSTEM.

and likewise in having the vessel, which goes from the net-
work into the vein small in proportion to the size of that net-
work ; so that the lymph must be lodged some time in those
parts before it is poured into the mass of blood. In birds I
also observed something like this, their lymphatic system being
enlarged, or varicose at different parts ; but these enlargements
are small in proportion to those above mentioned in fish and
in the turtle.

As to the manner of discovering those vessels in a fish, one
might naturally suppose, that when it is known where the re-
ceptaculum, or any of the larger parts of this system lie, it
could not be difficult to find them ; but the coats of these ves-
sels are so thin and transparent, that it is by no means easy.
The readiest way of finding the whole system is, to look for
one of the vessels which lie close to the skin ; as, for instance,
that which runs up exactly on the middle of the belly of the
haddock, cod, and other fish of the same shape. This vessel is
easily seen, as it grows pretty large at its upper part, near the
head, and if a pipe be introduced, the whole system may be
filled by its means.

It is partly owing to the ease with which those vessels
may be seen, after discovering where their larger branches lie,
that I have not added a figure of this system in a fish. Indeed
it would be almost impossible to express all its parts in one
figure, from the numerous and intricate communications of
those vessels near their termination in the common veins.
But I formerly laid before the Royal Society a haddock with
its lymphatics and blood-vessels filled with coloured injections,
to be compared with the description which was printed in the
Philosophical Transactions, vol. 59. And those that are de-
sirous of prosecuting this subject further, will, I flatter myself,
find it an easy matter to fill the whole system by attending to
what I have said above.

CHAPTER VII.

ON THE PROPERTIES OF THE LYMPH CONTAINED IN THE LYM-
PHATIC VESSELS, AND OF THAT WHICH LUBRICATES THE
DIFFERENT CAVITIES OF THE BODY.

As the fluid contained in the lymphatic vessels resembles
water in the circumstances of transparency and want of colour,
thence their first discoverers denominated these vessels ductus
aquosi, and seem to have concluded that the lymph was nothing
but water.

This opinion some of the succeeding physiologists, particu-
larly the learned Boerhaave, rendered more probable, by sup-
posing that there were three series of arteries, the sanguiferous,
the seriferous, and the lymphatic, and that those lymphatic
vessels we are now describing were only veins corresponding
to the lymphatic arteries, to restore their lymph to the heart.
Thence the lymph seems to have been concluded the thinnest
part of our fluids ; in which opinion physiologists were con-
firmed by Leeuwenhoeck's theory, that the globules of lymph
were smaller than those of the serum, or of the red part of the
blood.

The fluids that moisten the different cavities of the body,
viz. that of the peritoneum, pleura, pericardium, &c., being sus-
pected to be formed solely from the condensation of that steam
which appears on opening an animal just killed, have thence
been also considered as mere water by some anatomists and
physiologists, who were confirmed in this opinion by observing
that in dropsies, where a great quantity of fluid is let out from
such cavities, it is commonly a mere water, seldom coagulating
either when exposed to the air or to heat.1

But, notwithstanding the plausibility of all the arguments

1 Agreeably to this opinion, these dropsies are said to be occasioned by an in-
creased secretion or an impeded absorption, which supposes that the fluids naturally
moistening these cavities are the same as those let out from them in dropsical cases.

158 LYMPHATIC SYSTEM.

from which such conclusions were made, with respect to
these fluids, it will appear in the sequel, that although they be
so transparent in living animals, and so watery in dropsies, yet
in animals in health they differ so much from water, that they
not only coagulate when exposed to heat, but also when merely
exposed to the air; in which circumstance they agree most
with that part of the blood called the coagulable lymph, as is
evident from the following experiments.1

EXPERIMENT I.

If, soon after killing an animal in health, the abdomen, tho-
rax, or pericardium be opened, and if a little of the fluid that
moistens these cavities be collected, which (even in cases where
the quantity is very small) may be done by gently scraping the
surface of these cavities with a wet teaspoon, and if the fluid
thus collected be suffered to rest, exposed to the air, it will
jelly as the coagulable lymph of the blood does. This is an ex-
periment which I have made on a considerable number of ani-
mals, viz. on bullocks, dogs, geese, and rabbits, and the result
of all the experiments was the same (LXVIII).

EXPERIMENT II.

If, immediately after killing an animal in health, a lymphatic
vessel be tied up properly, and then cut out of the body and
opened, so as to let out the lymph into a cup and expose it to
the air, it will jelly as the coagulable lymph of the blood does
in the same circumstances ; this experiment I have likewise
made several times on dogs, asses, and geese.

1 From amongst those who concluded these fluids a mere water should be excepted
M. de Haller. (See his El. Phys.) And Professor Monro says they coagulate by cold
and rest. (Ob. An. and Ph. p. 68.)

(LXVIII.) The fluid from the pericardium of horses, shot on account
of lameness, does not always coagulate spontaneously, as I have ascer-
tained ; yet it did in two trials, as mentioned in Note xvm, p. 31, when
mixed with serum from the same animal's blood. I carefully looked
into the pericardium of each of the four suffocated human subjects
noticed in Note xxxin, p. 69, and found no coagulated lymph what-
ever, nothing but a little straw-coloured and transparent fluid, not more
than from a quarter to half a drachm in each pericardium. Some
colourless fluid which coagulated spontaneously from the belly of a
tortoise, is mentioned in Note xxvn, p. 53.

LYMPHATIC SYSTEM. 159

With respect to that fluid which moistens the cellular sub-
stance, or cellular membrane, as it is called, I cannot speak
with so much precision, since it cannot be collected in animals
in health ; but when we consider how great a probability there
is of the lymphatic vessels absorbing that fluid, we may suspect
that it is similar to what moistens the pericardium, thorax, ab-
domen, &c., especially as I have repeatedly observed, that the
lymph returning from the extremities by their lymphatic ves-
sels coagulates when exposed to the air equally as the lymph
nearer the centre of the body.

Since, then, those fluids in healthy animals coagulate sponta-
neously on being exposed to the air, may we not conclude that
they resemble the coagulable lymph of the blood at least more than
they do the water, or even than they do the serum, which does
not jelly on being exposed to the air ? And is it not an argu-
ment in favour of this inference, that such a fluid appears fitter
for the office of lubrication than mere water, and more similar
to the synovia, 'which of all fluids is the best adapted to that
purpose? (LXIX.)

(LXIX.) Professor Miiller,* like Hewson, regards the self-coagu-
lating property as essential to lymph. Dr. Davy has favoured me
with the following note on the fluid in the lymphatic vessels of the
spermatic cord of the ram : " The lymphatic vessels were large, and
distended with a colourless fluid ; it did not coagulate spontaneously,
but afforded a considerable and rather dense coagulum when treated
with nitric acid." In the careful observation of Mr. Lane,b fluid from
the lymphatic vessels of the horse coagulated in about ten minutes.
This corresponds with my own observations on the contents of the lym-
phatics of the dog and horse ; but in some trials the colourless fluid never
coagulated spontaneously. It is therefore probable that self-coagulation
is not an essential property of lymph. In reference to the statement
in the text, that serum does not coagulate on exposure, it will be
recollected that certain varieties of serum will coagulate spontaneously
when mixed together: see Note xvm, p. 31. Hewson is not just to
his own observations, when he compares coagulable lymph, or the fluid
of the lymphatics, to synovia.

For an account of the properties of lymph, see Muller's Physiology,
tr. by Dr. Baly, i, 258 et seq. ; Professor Wagner's Physiology, tr. by
Dr. Willis, vol. i, pp. 250 et seq. ; Mr. Lane's article, Lymphatic Sys-
tem, in the Cyclopaedia of Anatomy and Physiology ; and the Appendix
to the English version of Gerber's Anatomy, pp. 95 et seq., Plates xxxii
and xxxiii.

a Physiology, tr. by Dr. Baly, i, 259. b Cyclop. Anat. and Physiol. iii, 219-20.

160 LYMPHATIC SYSTEM.

But although from these experiments I am convinced that
the lymph in these cavities and vessels of a healthy animal
will always jelly on being exposed to the air (LXX), yet I have
likewise observed that the strength of that jelly is different in
different animals. In geese these fluids jelly sooner than in
dogs, and in the same animals the jelly differs in the different
circumstances of health ; in most of the dogs which I exa-
mined, the contents of the lymphatics formed a strong jelly, but
in a dog which I had fed eight days with bread and water,
and that rather sparingly, the lymph formed a very weak jelly;
and in young geese, these fluids are later in jellying than in
such as are full grown. I have observed the same of the fluid
contained in the pericardium and abdomen of other animals,
which fluid, when in a small quantity, always formed a strong
jelly, but when more copious, and the animal more feeble, the
jelly was thinner ; and in dropsical cases, it is well known that
the fluid let out of these cavities is not observed to jelly on being
exposed to the air, as it does in animals iii health ; but in some
cases it is found to coagulate by heat, like the serum of the blood,
and in others it only becomes a little turbid when boiled, owing
to the coagulable matter being in very small proportion to the
water.

Although this lymph becomes more watery in a weak state
of the animal, it 'is less watery and more coagulable in some
diseases.

But, what is a more curious fact, in those cases where I
have compared the fluid contained in the abdomen and peri-
cardium with that contained in their lymphatic vessels, of ani-
mals in different states of health, I have always found them
agree with one another in the degree of coherence of the jelly
which they formed. For, when the animal was in perfect
health, the lymph from the cavity of the pericardium, abdomen,
and pleura formed a strong jelly, and that in the lymphatics of
the neck and extremities was equally firm. When the animal
was reduced, as in the dog fed eight days on bread and water,
or when the goose was very young, then the jelly, formed by
the fluid collected in these cavities, was weak, and that formed
by the lymph in the lymphatic vessels was likewise weak in

(LXX.) See Note LXIX.

LYMPHATIC SYSTEM. 161

the same proportion. Sa that although these fluids vary in
the different circumstances of health, yet they always agree
with each other (LXXI).

These fluids, likewise, as we have before observed, besides
agreeing with one another, approach to the nature of the coagu-
lable lymph of the blood in the circumstance of coagulating
when exposed to the air, but they differ from it in the time
necessary for that coagulation. In dogs that were seemingly
in perfect health, whose blood and whose lymph were let out
of their vessels at the same time, the lymph was found to be
much later in coagulating than the blood. The time which
the blood requires for its coagulation is about seven minutes
after exposition to the air, but the lymph let out from the
lymphatic vessels of the same animals was found to require
half an hour, or more, for its coagulation. And although the
blood coagulates soonest in the weak animals, yet the contents
of the lymphatic vessels, or the fluids in these cavities, do not,
but seem later in jellying in proportion as the animal is re-
duced, or as they become more watery.

Moreover, the coagulable lymph of the blood and the lymph
of the lymphatic vessels not only differ from one another in
the time which they require for their coagulation when exposed
to the air, but also they differ more evidently in the time re-
quired for their coagulation in the body when merely at
rest, without being exposed to air. As, for instance, in a dog
killed whilst in health, and whose veins and lymphatic vessels
were tied up immediately after his death, the blood in the
veins was completely jellied in six hours, but the lymph in the
lymphatic vessels of his neck was perfectly fluid twenty hours
after his death, and, being let out at this time, jellied after
being for some time exposed to the air.

There is another change of the lymph very evident besides
those already mentioned, for it not only is varied from the
natural state to the more watery, but also from the natural to

(LXXI.) Professor Mullera says, that in frogs kept long without food,
the blood frequently loses its property of coagulation, and that in such
cases the lymph also does not coagulate ; though it usually coagulates
quickly, like the blood, when these animals are healthy and active.

a Physiology, tr. by Dr. Baly, i, 145.

11

162 LYMPHATIC SYSTEM.

the more viscid or coagulable; instances of which occur in
those inflammatory crusts that are found, in some diseases, to
cover the different parts of the body. Thus the outside of the
heart and the inside of the pericardium are sometimes covered
with a crust as tough as the size in pleuritic blood, and the
surface underneath has marks of inflammation, but is not
ulcerated (LXXII). Probably, therefore, it is the inflammation
which produces that change, or which makes the exhalant
arteries secrete a lymph with such an increased disposition to
coagulate. Add to this, that the change which inflammation
thus seems to produce is just the opposite to that produced by
the dropsy, for in the dropsy the fluid is secreted with an extra-
ordinary quantity of water and too little coagulable matter ;
but in inflammations the fluid is secreted with a greater pro-
portion of coagulable matter, and with less water ; and in some
instances it seems to be a pure coagulable lymph, either un-
changed by the exhalants, and then coagulating gradually on
being at rest, as the coagulable lymph is found to do in the
veins that are tied;1 or else the exhalant vessels have the
power of changing its properties, so as to make it coagulate
in an instant after being secreted. And this supposition of
the exhalants having a power of changing the properties of the
lymph is rendered probable from the following consideration,
viz. that it is sometimes found coagulated in the inner surface
of the heart, forming a crust, similar to what we so often see
on the outside. Now as there is a constant current of blood
through the heart, unless the lymph forming that crust had
coagulated instantly on being secreted, it must have been
washed off by the blood. One of the clearest instances of
this was observed by Sir John Pringle, who has given me

1 See Exp. Inquiries, part i, p. 22.

(LXXII.) Dr. William Hunter, as early as the year 1/57, observed
that pus may be formed without any breach in the solids ; and John
Morgan/ of Pennsylvania, soon afterwards described pus as a secre-
tion. The coagulated lymph on inflamed serous membranes, here and
at page 164, so accurately characterized by Hewson, Dr. Hunter called
" a glutinous concretion, or slough." See the Introduction.

a De Puopoiesi, sive Tentamen Medicum Inaugurate de Puris Confectione, p. 5, 8vo,
Edin. 1763.

LYMPHATIC SYSTEM. 163

leave to transcribe from his notes the following circumstances
of the case :

" Mr. J — , who had for some time been subject to palpita-
tions of the heart, and who (perhaps from another cause) hap-
pened to die apoplectic, was carefully opened after death, and
two ounces of water were found in the ventricles of the brain.

" The heart was large, and adhered in some places to the
pericardium in such' a manner as parts adhere from recent in-
flammation, that is, by an exudation of coagulable lymph. In
the pericardium was found a small quantity of bloody serum,
of a dark brownish cast. There were marks of inflammation
on the surface of the heart, and some part of the coronary
artery was ossified. In the right ventricle and in the pul-
monary artery was a large concretion of the kind erroneously
supposed a polypus, the upper part being white and sizy, whilst
the lower had only the appearance of a dark coloured con-
gealed blood. It was obvious that this concretion was formed
after death (LXXIII). On the external surface of the left
ventricle, near the septum, was a tumour, which on being cut
into was found to contain above half a spoonful of a dark,
reddish-coloured matter, of the consistence of pus, nor was
there any doubt of its being produced by suppuration. This
abscess would have broken into the left ventricle, had not the
opening through the septum been covered and shut up on the
side next that ventricle by a crust or polypus of the shape
and about the size of half a large pigeon's egg, divided long-
wise, so that the flat side lay towards the mouth of the ab-
scess, whilst the convex side was turned towards the ventricle,
and occupied a space in it. This," adds Sir John Pringle, " was
a true polypus ; it cut tough, or like the coagulated blood of
aneurisms of old standing, nor was there any doubt, from its
appearance, of its having existed there for a considerable
time."

Now this crust or polypus, lying over an inflamed surface,
had probably been formed by a secretion of the lymph from
the inflamed vessels, and being formed in the cavity of the
heart where there was a constant current of blood, the lymph

(LXXIII.) On the relative position of the red and white parts in these
clots, see Note xin, p. 24.

164 LYMPHATIC SYSTEM.

of which it was composed must, I think, have coagulated in-
stantly on being secreted from the vessels, otherwise it would
have been washed off with the current ; and as the coagulable
lymph is not naturally disposed to coagulate so instanta-
neously, it is probable that the diseased vessels here possessed
the power of producing that change ; and therefore, that as in
dropsical habits, where the vessels act weakly, the fluids ex-
haled are of a watery tenuity ; so in inflammatory cases, where
the vessels act strongly, those secreted fluids, in consequence
of that strong action, acquire a more viscid and a more coagu-
lable nature (LXXIV).

And moreover, as it appears that the properties of the lymph
exhaled upon surfaces and into cavities differ so widely in differ-
ent circumstances, and as we find that pus is often met with in
such cavities without ulcerations (see Note LXXII), is it not pro-
bable that pus itself is merely that lymph changed in its pro-
perties by passing through inflamed vessels? The cavities of the
pleura, pericardium, &c., are sometimes observed to contain
considerable quantities of pus without the least mark of ulcer-
ation, instances of which I have seen. In one patient I found
three pints of pure pus in the pericardium, without any ulcer
either on that membrane or on the heart. In another, the
cavity of the pleura of the right side was distended with a pus
that smelled more like whey than a putrid fluid, and the lungs
were compressed into a very small compass ; but there was no
appearance of ulcer or erosion either on these organs or on
the pleura, but only under the pus was a thin crust of coagu-
lable lymph. In such cases it is manifest the pus must have
been formed from the fluids ; and as the exhalant vessels at
one time appear to secrete a mere water, -at another a coagu-
lable lymph, and in a third (when a little inflamed) they secrete
that lymph so viscid, and change its properties so much as to
make it coagulate instantly on being secreted; so in like man-
ner they may sometimes, when more inflamed, have the power
of converting the lymph into pus ; and, according to the kind

(LXXIV.) As to the consistency of the liquor sanguinis, and state of
the red corpuscles in inflammation, see Note xxm ; detailed experi-
ments and historical notices on the subject are given in my paper on
Buffy Blood.a

a Edin. Med. and Surg. Journ. Ixiv, 360 et seq.

LYMPHATIC SYSTEM. 165

and degree of the inflammation, the pus may vary from the
bland, viscid, and inodorous nature, to that of the most thin and
fetid sanies found in phagedenic and cancerous ulcers. And if
pus in these cases is produced merely by a secretion (see Note
LXXII), so likewise, it would seem probable, that even in ab-
scesses, where there is a loss of substance, it is not the melting
down of the solids that gives rise to the pus, but the pus
being secreted into the cellular membrane, from its pressure, and
from other causes, deadens the solids and then dissolves them ;
which is confirmed by observing that even a piece of fresh
meat, if put into an ulcer and covered up, is soon destroyed or
melted down by the pus, which is thereby rendered more
fetid (LXXV). And this opinion that pus is made by a secre-
tion is strengthened by observing that in its pure state it is
full of globules ; in which circumstance it agrees with milk,
which is produced by a secretion, and not by a fermentation.1

Upon the whole, then, it appears that the lymph contained
in the lymphatic vessels, and the fluids which moisten the dif-
ferent cavities of the body, as the pleura, peritoneum, &c.,
instead of being a mere water in healthy animals, are coagu-
lable fluids (see Notes LXVIII and LXIX), approaching to the
nature of the coagulable lymph of the blood, of which pro-
bably they are a species, or are composed of a mixture of
that lymph with water, that the proportions of that mixture
vary from the dropsical habit, where the coagulable lymph is
in a small, and . the water in a great proportion, up to the
rheumatic or inflammatory habit, where the lymph abounds,
and the water is in less proportion ; and that in some cases
the lymph, in passing through inflamed vessels, is even con-,
verted into pus.

1 See Professor Morgan's ingenious Dissertation, De Puopoiesi.

(LXXV.) According to the experiments of Sir E. Homea pus has no
particular effect in dissolving muscular fibre, which agrees with the
result of several trials that I made. The effect on the muscular fibre
mentioned in the text, probably arose from putrefaction, favoured by
the heat of the ulcer. Pus itself is less prone to putrefaction than
blood and most animal juices.

* On the Properties of Pus, pp. 32-36, 4to, Lond. 1788.

CHAPTER VIII.

OF THE MANNER IN WHICH THE LYMPH IS SECRETED INTO

HAVING in the preceding chapter spoken of the properties
of the lymph moistening the different cavities of the body, I
shall in this consider the manner in which that lymph is
formed, or secreted from the mass of blood.

The most generally received opinions concerning this secre-
tion have been, that it was performed either by small exhalant
arteries, or else by pores on the sides of the vessels, which
pores were believed to be organized.

But these opinions have been controverted by a celebrated
anatomist,1 who has endeavoured to prove that this secretion
was not performed by exhalant arteries, or an effect of what is
properly called organization, but merely by the thinner or
more watery parts of the blood nitrating or transuding through
the inorganized interstices between the fibres of our vessels
and membranes ; so that, according to this idea, the fibres of
our vessels were close enough to retain the serum, or the red
globules, but not close enough to prevent the water oozing out
as through a sieve, and the arguments with which this doctrine
is supported are as follow :

First. The ready transudation of water and other injections
after death.

Secondly. The transudation of blood after death, but not
during life; for during life he supposes the blood to be thick-
ened by the coagulable lymph ; but when that lymph is jel-
lied, he concludes the rest of the blood is thereby made thinner,
and therefore more capable of oozing through the inorganized
interstices by which it could not pass before.

Thirdly. The transudation of bile, which he thinks takes

1 Dr. Hunter.

LYMPHATIC SYSTEM. 167

place in the living body, because on opening a dead one we
see all the neighbourhood of the gall-bladder tinged with this
fluid.1

Such are the arguments brought in favour of transudation;
but, on a careful examination, they are not so satisfactory as
those which may be produced in defence of the opinion that
these secretions are by organized passages, as I think will ap-
pear from the following observations :

First. Although fluids do transude on being injected into
the vessels of the dead body, yet we must not thence conclude
that a similar effect would certainly take place in the living ;
for it is probable that " our fibres and vessels have a degree of
tension which they may lose with life." Besides, if transuda-
tion took place in the living body, it would seem to defeat the
principal purpose for which the blood-vessels were made, that
is, the containing and conveying the fluids ; and upon drink-
ing a greater quantity than ordinary of watery liquors, instead
of the liquors being carried to the kidneys or other emuncto-
ries, and thereby thrown out of the body as a redundancy,
they would escape into the cellular membrane, and occasion an
anasarca. That this would be the case will appear the more
probable, when it is considered how small the fibres of our
blood-vessels must be, and therefore what millions of pores (did
they exist) the water would be exposed to from its entrance
into the stomach, and its passage through the lacteals, the
thoracic duct, the veins, the heart, the lungs, and the arteries,
before it reached the kidneys. So that were we in imagina-
tion to follow a drop of these liquors, according to the idea of
transudation, we should find it first leaking through the sto-
mach or through a lacteal, then being absorbed, then escaping
a second time, and being again absorbed, &c., an idea by no
means consistent with what we know of the works of nature,
who, as a learned and ingenious author says of, her, "Operam
suam non ludit, neque quod actum est agit denuo."3 It is
more probable, therefore, that as the blood-vessels are made to
contain and convey the fluids, nature has taken care to con-
struct them properly to prevent this purpose being defeated.

Secondly. To suppose that the fluids which moisten the

1 See Dr. Hunter's Medical Commentaries, part i, p. 40.

2 Dr. Glisson,

168 LYMPHATIC SYSTEM,

different cavities of the body, as the pericardium, pleura, peri-
toneum, tunica vaginalis, &c., get into these cavities merely by
transudation, is to suppose, not only that the small vessels in
contact with these membranes have inorganized pores, but also
that these membranes themselves have the same just opposite
to those of the vessels. Now if we admit inorganized pores at
one part of those membranes, we must admit them in all parts,
and in the same degree ; but as the blood-vessels are circular,
and touch those membranes only by a small part of the circle,
the parts touched by the vessels must be smaller than the
interstices between the vessels, and the lymph must have fewer
chances in favour of its leaking from the vessels into the cavities,
than of its oozing again from these cavities into the interstices
between the vessels or into the cellular membrane ; so that, if
these membranes admitted of transudation, there would be no
such thing as a partial dropsy, for the water would run out at
one part of the pleura, pericardium, peritoneum, &c., as fast as
it ran in by the other, and an anasarca would always accompany
an ascites ; which not being a fact leads us to believe, that
those membranes do not admit of transudation in living bodies,
and that the fluids get into them not by inorganical, but by
organized passages.

Thirdly. To prove more satisfactorily that these fluids are
not filtrated from the blood merely by inorganical transudation,
let us recollect the experiments related in the last chapter con-
cerning the properties of those fluids, which we found varied
in different circumstances of health. For, in inflammatory
affections of the parts from which they were secreted, they
assumed the appearance of the coagulable lymph of the blood,
and formed a tough jelly ; in animals in health they formed a
jelly of a weaker nature ; and in dropsical cases they were al-
most a mere water, without the property of coagulation. Now
if these fluids be so variable in their properties, it is manifest
that the passages secreting them cannot be always unalterably
the same, or inorganized; since at one time we find them secreting
one fluid, and at another time secreting another; especially as we
sometimes find them secreting a fluid very different from the
blood, viz. pus. Which pus being found in cavities without any
ulcer or erosion (see Note LXXIT), we must conclude it formed
by something more than a mere filtration; for we cannot suppose

LYMPHATIC SYSTEM. 169

there should be filtrated from the blood a fluid that was not in it.
And if pus, which passes from the same pores, can only be account-
ed for by supposing these pores to be organical, in like manner
is it not probable, that the secretion of the natural lymph is not
a straining through inorganical,but through organized passages?

Lastly. It has been brought as an argument in favour of
transudation in the living body, that blood transudes after death,
and this has been explained on the supposition that the blood
was thicker before the coagulation of the lymph. Which
supposition appears ill-founded, when we speak of the living
body ; for in former experiments1 we have observed that this
lymph, frequently at least, rather thins than thickens the
blood (LXXVI). If therefore the blood transudes in the dead
and not in the living body, we should rather attribute it to a
change in the vessels than in the blood, as is probable from a
careful examination of that very fact which has been brought
as the principal argument in favour of transudation, viz. the
parts adjacent to the gall-bladder being tinged with bile ; for
any one who will take the trouble of standing by a butcher,
whilst he kills a sheep, will find the contrary to that gentleman's
conclusion, that upon opening the animal immediately there' is
no appearance of the gall having transuded, for none of the
parts surrounding the gall-bladder are tinged. But let the
animal continue a day or two unopened, and then the gall will
be found to have transuded, and to have tinged the neighbouring
parts ; as is the case in the human body by the time that we
inspect it.

Since then the gall-bladder so readily allows of transudation
after death, and not during life, is it not probable that there
is in our membranes and our blood-vessels a degree of tension,
or a power of preventing the fluids oozing out of them, which
power is lost with life ? (LXXVII.)

1 See Exp. Inquiries, part i.

(LXXVI.) See Note xxni.

(LXXVII.) Hewson's view is supported by the experiments of Dr.
Davy,a showing that the fresh urinary bladder is perfectly retentive
of water, though it passes slowly through after a few hours ; and still
later, when the bladder becomes putrid, the water passes as through
coarse filtering paper.

a Researches, Physiol. and Anat. vol. ii, pp. 250-51.

170 LYMPHATIC SYSTEM.

Upon the whole then it appears, that the interstitial lymph,
or the fluid which moistens the different cavities of the body,
being different from mere water, cannot be produced simply by
transudation through inorganical interstices; but that there
are small exhalant arteries, or organized passages, which not
only transmit the lymph from the blood, but change its pro-
perties, and adapt it to the office of lubrication, and likewise
make it assume very different appearances in different circum-
stances of health (LXXVIII).

(LXXVIII.) The accuracy of this opinion is supported by the recent
observations on the agency of cells in secretion, of which an account
will be found, with reference to the researches of Purkinje, Henle,
Goodsir, and Bowman, in Dr, Carpenter's Report on the Origin and
Functions of Cells, Brit, and For. Med. Rev. xv, 279. Some of Mr.
Goodsir' s works are referred to in Notes LXXXII and LXXXIII. The
fact that the fluid of the ventricles of the brain rarely contains coagu-
lable lymph, and commonly but a very little albumen, is also in favour
of Hewson's view. Were this fluid merely an exudation, as the vessels
of the brain seem to have very thin coats, might it not be expected
that the fluid from them would be rich in albumen and coagulable
lymph ?

CHAPTER IX.

AN EXAMINATION OF THE OPINION WHETHER THE COMMON VEINS
DO THE OFFICE OF ABSORPTION.

As there is a secretion upon the different -surfaces, and into
the different cavities of the body for the purposes of the con-
stitution, so there is likewise an inhalation or an absorption.
For example, if food be taken into the stomach and intestines,
it is there digested, and being converted into chyle, it is in
that form taken into the blood-vessels. If garlic be applied to
the skin it gets into the body, and is smelt in the breath with
as much certainty as when taken into the stomach, where its
juices are absorbed by the lacteals. So likewise terebinthinate
medicines applied to the skin are soon smelt in the urine,
and cantharides in a blister affect the urinary passages.

In the same manner fluids are taken from different cavities
of the body into the vascular system. Thus the water of an
ascites and an anasarca are occasionally taken up and carried
by the blood-vessels to the intestines and kidneys, and evacuated
by stool or by urine. And the pus of an abscess is sometimes
absorbed, and carried to distant parts of the body and there
deposited, or is evacuated by the intestines or urinary passages.
So also fluids injected into cavities, as that of the chest or the
belly of living animals, soon find their way into the blood-
vessels (LXXIX). These circumstances are admitted by anato-
mists amongst the unquestionable facts of physiology.

(LXXIX.) It is curious with what rapidity water is absorbed when
injected either into serous sacs or into the subcutaneous filamentous
tissue. In February 1839, I opened the tunica vaginalis testis in three
dogs, and through it injected one pint of water into the peritoneum of
the first dog ; two pints into the second ; and three pints into the third.
The water in each case was well secured in the belly by a ligature on the
neck of the tunica vagiualis. The temperature of the air was 56° and of
the water 54°. In each trial, all the water had disappeared forty-nine
hours after the injection ; and the peritoneum had no marks of innamma-

172 LYMPHATIC SYSTEM.

Nor do anatomists differ in their opinions about the mode
in which these fluids are taken up, for it is universally allowed
to be by absorption, or that there are small orifices (see Note
LXXXIII) adapted to imbibe them; the only question is, what the
vessels are to which these orifices belong, whether to the lympha-
tic system, or to the common veins (see Notes LXV* and LXXXII) .

That the common veins did the office of absorbing both the
chyle and the lymph was the opinion of anatomists before
Asellius discovered the lacteals ; but after his time few doubts
were entertained of the lacteals absorbing, at least, a part of
that fluid. But most anatomists have been so tenacious of
the old opinion as still to believe, that the veins partly per-
formed that office, or absorbed some of the chyle and carried
it to the liver,

As to the absorption of the lymph, they have been still
more positive of its being performed by the common veins ;
nay, even after the discovery of the lymphatic vessels it occurred
but to few that these vessels contributed in the least to this
absorption. And no wonder, since, besides the respect for the
contrary opinion, because it was transmitted from antiquity,
anatomists thought themselves possessed of many strong argu-
ments in favour of the • common veins performing absorption ;
and as these arguments still continue to have weight with some
modern physiologists, we shall make a particular examination
of them in this chapter.

First. That the common veins arise from cavities, especially
in the intestines, and do the office of absorption, is thought
probable from injections into these veins in dead bodies having
sometimes passed into those cavities, even in cases where but
little force was used. This is a circumstance which has oc-
curred in the experiments of the most eminent anatomists, both
of the past and of the present age, so that there is no fact in
anatomy in favour of which more respectable authorities might
be produced. And yet whoever has made numerous experi-
ments with injections, must be convinced how easy it is to be

tion. In other trials, water seemed to be absorbed still more quickly
from beneath the skin. Blood injected, immediately after it was drawn,
into the pleura and into the peritoneum, was readily absorbed, but not
so rapidly as the water.

LYMPHATIC SYSTEM, 173

deceived by them in this matter. For the veins in dead bodies
being easily ruptured, whenever we see injections get from them
into cavities, we have reason to doubt whether these injections
had passed by natural passages or by laceration of the small
vessels ; and whoever will examine the authorities that have
been quoted in defence of this fact, will find that an equal
degree of credit has been given to experiments made with such
coarse materials as no experienced injector will now believe
could pass through such small orifices,1 as to those injections
which from their subtilty leave the point more doubtful. Be-
sides, as we found in the former chapter, such changes are pro-
duced upon animal bodies by death, that membranes, which dur-
ing life had been so tense as to prevent transudation, after death
were so much altered (see Note LXXVII), that in the gall-bladder,
for example, they allowed the viscid bile to pass. Does it not
therefore become doubtful, when an anatomist injects a cavity
from a vein, whether (although he cause no rupture) he may
not separate the fibres already relaxed by death, in such a man-
ner as to imitate this transudation? And if one anatomist
has been misled when he concluded transudation took place in
the living body, because he found it in the dead body, so may
they likewise, who have concluded veins arose from cavities in
the living because they had been able to push injections into
such cavities in the dead body. It must therefore, I think, be
allowed that' such experiments are at the best equivocal.

Another argument used in favour of veins arising from cavi-
ties, particularly from the intestines, is that some anatomists
have affirmed that they have seen white chyle in the blood
taken from the mesenteric veins. But this argument will
appear very inconclusive, when the reader recollects, that the
serum of the blood let out from the veins of the arm is some-
times white, which must arise from some other cause than
these veins absorbing chyle (LXXX). And, therefore, if that
appearance in the brachial veins can be otherwise accounted

1 For example, Dr. Hales's injection of tallow, resin, and turpentine varnish ; which
being injected, a part of the vermilion got into, the bowels, although no greater force
was used than that with which the blood circulates in the living body ; but then it
is probable that the vessels are weaker in the dead than in the living animal.

(LXXX.) See Note LVIII.

174 LYMPHATIC SYSTEM.

<

for than by absorption, we are left in doubt whether in those
instances, where anatomists observed such a fluid in the veins
of the mesentery, it had been owing, not to those veins absorb-
ing it, but to their receiving it from the arteries. All the
serum of the body being now and then as white as milk.1

A third argument produced in support of absorption by the
common veins is taken from the structure of the penis, whose
veins arise from its cells ; which cells, however, are now allowed
to be particular organizations, and very different from those of
the cellular membrane, and the blood is believed not to be
absorbed, but to be impelled from these cells into those veins ;
and the argument is now given up even by some of those who
were once the most strenuous in its favour.2 It need not
therefore be here dwelt upon.

Ligatures, or compression on the large veins, have been
considered as furnishing a fourth argument in favour of these
veins arising from cavities, and doing the office of absorption.
Thus the swelling of the legs in pregnant women, and in cases
where tumours have been seen near the veins, has been ex-
plained from the uterus in the one case, and the tumours in
the other, occasioning such compression, as to prevent the re-
turn of the venous blood. But there are two circumstances
which make this argument far from being satisfactory. First,
the lymphatic vessels run near such veins, and it is doubtful
whether the lymph may not be retained in th6 limbs more
by the compression of these vessels than by that of the veins.
Secondly, the compression of a vein may, by stopping the
return of the blood, not only distend the small veins, but the
small arteries, and the exhalants may be so dilated, or so
stimulated, as to secrete more fluid than they did naturally.
In this way, perhaps, the ligature which Dr. Lower made on
the cava inferior of a dog occasioned the ascites.3 An experi-
ment which I have repeated, but my subject did not live so
long as his, for mine died in half an hour, and had only a
very little water in the abdomen (LXXXJ).

1 Instances of which may be seen in the first part of these Exp. Inquiries.

2 See Professor Monro's State of Facts. 3 De Corde, cap. ii, p. 112.

(LXXXI.) (Edema of the lower limbs is much more frequently con-
nected than is commonly supposed with obstruction of the veins by

LYMPHATIC SYSTEM. 175

Lower has related another experiment which has frequently
been quoted by writers on the dropsy ; that is, where he tied
the jugular veins of a dog, and the dog's head became dropsical.
Now were this an experiment which always succeeded it would
be more decisive, for when the whole cava was tied, no part of
the blood being able to return, all the vessels below, not only
the small veins, but the small arteries, must have been extremely
distended. Whereas in this experiment no such thing would
take place, because the jugular veins so frequently communicate
with other vessels, that there would still be a regress allowed
to the blood ; if the neck therefore became oedematous, it would
appear more likely to have been occasioned by the ligature on
the veins. But what shows that there must have been some
fallacy in Lower's experiment is, that these veins have since been
frequently tied without an oedema being produced, or any signs
of extravasated lymph. Thus, in not one of the experiments
which I made on these veins in living dogs (as related in the
first part of these Experimental Inquiries) was this effect ever
produced ; and Baron Van Swieten tied up both the jugular
veins, and though he kept the dog four days afterwards, did
not observe him any way incommoded.1 In one dog I even
cut out both the external jugulars, and kept him near a twelve-
month without observing the least symptom of dropsy. I
should therefore suppose, that in Lower's experiment, not only
the veins, but the lymphatic vessels which lie near them, had
been tied; in which case the lymphatics 'would burst and oc-
casion these symptoms. But in my experiment I took care
to separate the vein from the lymphatics.

These arguments, therefore, in favour of absorption being
performed by the common veins, which are brought from ex-
periments where ligatures were made on large vessels, seem
likewise to be liable to fallacy.

A fifth argument is taken from the structure of the placenta,
where it has been concluded there are no lymphatics ; and yet
there must be absorption, and not a communication of the

1 Comment in Boer. Aph. § 170, p. 266.

coagulated blood ; see Note xui, p. 24. I long ago deposited pre-
parations illustrating this fact in the museum of the Army Medical
Department at Chatham.

176 LYMPHATIC SYSTEM.

vessels ; neither of which arguments are decisive. For there
may be lymphatics in the placenta, though not yet discovered ;
or there may be small vessels passing from the mother to the
foetus, though not yet injected.

A sixth argument is furnished by the experiments of some
authors, in which experiments it is affirmed, that fluids injected
into the intestines were soon afterwards discovered in their
mesenteric veins. The experiment related by the ingenious
Kauw Boerhaave, has been the most depended upon in this
matter.1 In which experiment water was injected into the
intestines, and those intestines being compressed, the water
was afterwards observed to run from the veins; but that
some fallacy had crept into this experiment is now probable,
from its having been repeated several times in a very satisfac-
tory manner,2 without being attended with the like success.
The learned M. de Haller, indeed, in comparing these argu-
ments, says, that in such cases where authority seems to ba-
lance authority, he chooses rather to adopt the opinions of those
who affirm than of those who deny the fact. Eor, as he ob-
serves, this experiment may easily fail of success ; but if it has
ever succeeded, we shall not easily find another way of account-
ing for it, except by allowing that these veins open into the
intestines.3 But, with due deference to the opinion of this
excellent author, Kauw Boerhaave's experiment is not so con-
clusive as those alluded to above; for in his, the dog was
opened immediately "after death, and water being injected into
his stomach, that water was seen first to dilute the blood,
then to wash it from the vena portarum, and the experiment
was continued a considerable time by means of pressing the
stomach, which pressure furnishes a strong presumption that
the water did not get into the veins by .absorption but by a
laceration, especially as the experiment continued to succeed
for some hours after death ; whereas absorption always ceases
long within the first hour.4 This argument, therefore, which

1 See De Perspir. § 469-71. 2 Dr. Hunter's Medical Comm. chap. v.

3 Elem. Phys. lib. xxiv, sect. 2, § vi.

4 K. Boerhaave's words (after mentioning that the blood was washed out by the
wound made in the auricle of the heart) are as follow : " Tandem pura aqua tsedioso
labore per horas, lenissime immittere aquam et premere ventriculum continuavi donee
pallerent omnia vasa sanguine orbata per resorptam aquam." — See De Perspir. $ 470.

LYMPHATIC SYSTEM. 177

has been considered as so strong in favour of absorption by the
common veins, is liable to objections. And lastly, a seventh
argument used in favour of common veins absorbing, was, that
many animals were destitute of any other vessels which could
do that office. This was supposed to be the case with birds,
fish, and amphibious animals; all of which some anatomists
did not hesitate to affirm must want every part of the lymphatic
system, and with great appearance of reason; since in the
smallest quadruped they could easily find either lacteals or
lymphatic glands upon the mesentery, but in the- largest bird
or fish neither lacteal vessel nor conglobate gland could be
seen. And if these animals (said they) be without the lym-
phatic system, absorption in them must be performed by other
vessels, viz. the common veins ; and if in them the common
veins can do the office of absorption, why should not they
likewise perform it in the human body, where such veins equally
exist.1 But this argument is overthrown by the lymphatic
system being now discovered in all these animals.

Such are the arguments produced in favour of the common
veins doing the office of absorption, a doctrine which has lately
been espoused by that excellent anatomist, Dr. Meckel, to
whose observations, though agreeing with some already men-
tioned, it may be necessary to pay a particular attention.

Dr. MeckeFs conclusions in favour of this doctrine are
made entirely from injections in dead bodies. For, having
filled the common veins by injecting mercury into the lympha-
tic glands, into the excretorj- ducts of the breasts, into the
vesicula seminalis, into the hepatic ducts, and into the urinary
bladder, he concludes that the veins open into these parts in
the living body to absorb from them.2 A conclusion which
is already proved to be liable to considerable objections, as
we never can be sure whether our injection, in getting from
these cavities into such veins, had gone by a natural or by a
forced passage. Dr. Meckel does indeed mention that there
were no marks of an extravasation in his experiments. Per-
haps it might have been too small for observation. Nay, we
have even reason to believe that as the small vessels of the

1 See Prof. Monro's Obs. Anat. Phys. p. 57 ; Dr. Haller's Elena. Phys. lib. xxiv,
sect. 2, § 3, pp. 66-7.

2 See his Nova Experimenta et Observations, Berol. 1772.

12

178 LYMPHATIC SYSTEM.

human body are very close to one another, our injection may
sometimes burst from one into another lying in contact with
it, without distending the cellular membrane which lies be-
tween them. A circumstance which I have seen happen even
on the mesentery of a turtle, where upon injecting the lacteal s
I have more than once made the mercury pass into the com-
mon veins ; but in all these cases, on a careful examination,
I found it was by rupture, as could readily be distinguished
in this animal, whose mesentery is extremely thin and trans-
parent. And that it actually was so, and not by a natural
passage, must be evident to every anatomist, who considers that
this is an experiment which does not always succeed on the
mesentery of the turtle, where, if there were natural passages,
or if the lacteals opened into the veins, the mercury would
probably run with great facility.

And the very same circumstance which Dr. Meckel has ob-
served of a lymphatic gland has happened to me sometimes on
injecting these glands in diseased cases ; that is, I have filled
the common veins, and in some instances, where I looked for
it, I could distinguish the extravasation very readily, and
therefore concluded that in the other cases, where the veins
were filled, that it was also by an extravasation, though a
more obscure one. I should thence suspect that in Dr.
Mecke? s experiment, where he filled the common veins by in-
jecting into the lymphatic vessels of a diseased gland, a simi-
lar deception had taken place ; especially as the force applied
was considerable, he having used a column of mercury eighteen
inches high.

And the supposition of the red veins opening into a lymphatic
gland appears improbable from an observation concerning the
structure of the glands, for which we are indebted to Dr.
Meckel himself, namely, that they are made of a convoluted
lymphatic vessel.1 (See Note cxix*). Now to suppose a
lymphatic, which is a vessel given to absorb, should itself, even
when convoluted, have a common vein opening into it for absorp-
tion from its cavity, is not, I think, consistent with what we
know of nature's operations, who, to repeat the words of Glisson,
" Operam suam non ludit, neque quod actum est, agit denuo."

Similar objections might be made to the other experiments

1 Epist. ad Hallerum.

LYMPHATIC SYSTEM. 170

related by this very ingenious author; but enough, I think,
has been said to show how cautious we -should be in making
conclusions with respect to the passages of the living body,
from experiments made on the dead, where, from the weakness
of the vessels and other circumstances, we are so liable to be
deceived.1

Thus, on taking a review of the doctrine, that the common
veins are the instruments of absorption, that doctrine appears
to have no other support than respect for the authority of our
predecessors ; for all the arguments in its favour are liable to
considerable objections (LXXXII). Let us next, therefore, in-

1 Dr. Hunter and Dr. Monro found in theij experiments that injections readily
burst from the arteries into the lymphatic vessels, by the intervention of the cellular
membrane ; these experiments they at first considered (as Dr. Meckel does his) as
proofs of their having filled the natural passages; but more careful observations seem
to have now convinced the former of these gentlemen that such conclusions are fal-
lacious, and he now thinks that the injection may have burst into the sides of the
lymphatic vessel. See his Medical Commentaries, p. 5.

(LXXXII.) It is now generally admitted that imbibition takes place
through the coats of veins, lymphatics, and other tissues, and that the
veins convey various matters into the system. Indeed, absorption
or wasting of a tissue may take place where, in the healthy state,
neither blood-vessels nor lymphatics can be found, as mentioned in
Note LXV * ; the same tissue may also become thickened ; among other
examples, those of hypertrophy and atrophy of the articular cartilages
may be mentioned : see 'Description of the diseased Joints in the Fort
Pitt Museum,' sect, ii, iii, 'Edinb. Med. and Surg. Journ.' vol. xlviii,
pp. 67-70. Mr. Toynbeea concludes that certain tissues are capable of
being nourished without the presence within them of blood-vessels.
And Mr. John Goodsirb has pointed out some organic processes in
which absorption and ulceration appear to be functions independent of
the vessels, which he considers as mere 'passive ducts in carrying
away the absorbed products. He concludes that, " the primitive cell
is primarily an organ of specific absorption, • and secondarily of nutri-
tion, growth, and secretion." The old mechanical notion, entertained
in Hewson's time, of regular pores or orifices in the vessels for absorp-
tion and secretion is now exploded. With a good microscope, it is
most easy to see fresh cells, as those of pus or of the semen, swell from
imbibing water added to them. From the observations of Tiedemann
and Fohmann, it was supposed that the chyle could be absorbed from
the mesenteric glands of the seal by the veins only ; but Dr. Knoxc

a Phil. Trans. 1841, p. 188. c Edinb. Med. and Surg. Journal, xxii,

b Anat. and Pathol. Obs. pp. 8, 14, 19, 23.

34, 8vo, Edin. 1845.

180 LYMPHATIC SYSTEM.

quire whether some other part of the human body may not do
that important office.

clearly proved that in this animal the chyle takes the usual course
through the lacteals and receptacle to the thoracic duct. MM. Flandrin
and Dangerd confirm the fact of the absorption of poison from the in-
testines by branches of the portal vein ; and Dr. Handyside6 made some
experiments, showing that the veins generally absorb various foreign
matters. A reference to his opinions, and to those of Dr. Carson/ will
show that there is still a doubt whether the colourless lymphatic ves-
sels absorb merely the effete or the nutritious elements of the body.
The lymphatics are not merely absorbents, for they alter the properties
of the fluid which they convey. Some interesting observations on the
functions of these vessels are given in the second Dr. Monro's 46th
Lecture.8

d Mr. Paget's Report, Br. and For. Med. f Notices of Communications to British
Rev. xix, 280. Association, August, 1836, p. 119.

« Notices of Communications to British « Essays, &c. pp. 3 et seq., ed. by his Son
Association, August, 1835, p. 92. and Successor. 8vo, Edin. 1840.

CHAPTER X.

ON THE USE OF THE LYMPHATIC SYSTEM.

THIS system in all animals, we have found, consists of a
trunk or thoracic duct, and of two extremities, namely, the
lacteals and the lymphatic vessels. The lacteals can be traced
from the thoracic duct to the intestines, through the coats of
which they pass, and open into their cavities by patulous ori-
fices (LXXXIII), in order to absorb the chyle and to transmit it
through the thoracic duct to the blood-vessels. That this is
their use has never been questioned since the first discovery of
those vessels, from its always admitting of easy demonstration,
that is, by giving an animal milk, and then opening him a few
hours after, in which case the same fluid that is seen in his
intestines can likewise be seen to have got into his lacteals —
a satisfactory proof of the lacteals beginning from the in-
testines.

(LXXXIII.) Before Hewson's time, it was a popular opinion3 that the
lacteals begin by open mouths in the villi of the intestines, and this view
continued to be generally entertained until lately. Mr. Sheldon,b after
stating that these mouths were discovered by Liberkuhn, declared that
"the ampullulae, with their orifices, are to be considered as the begin-
nings of the lacteal vessels." Mr. Cruikshankc figured what he con-
ceived to be these orifices. But Professor Miillerd found that mercury
injected into the lacteals does not escape from the surface of the mu-
cous membrane of the gut, and therefore he concluded, with Rudolphi,
that the villi are not perforated at their extremity. In short, it is now
well known that the radical extremities of the lacteals form loops, or
closed passages in the villi. See Mr. John Goodsir's paper on the Struc-
ture of the Intestinal Villi, 'Edin. New Phil. Journal,' xxxiii, 1 65 ; Henle,
'Anat. Gen.' tr. par Jourdan, t. i, 455 ; Mr. Paget's Report, 'Brit, and
For. Med. Rev.' xiv, 290 ; and Dr. Carpenter's < Human Physiology,'
pp. 372-3.

a Arbuthnot on Aliments, pp.17, 20, 8vo, c Anatomy of the Absorbing Vessels of
Lond. 1731. the Human Body, plate 2, fig. 3,4to,

b History of the Absorbent System, pp. Lond. 1786.

32-8, 4to, Lond. 1784. d Physiology, tr. by Dr. Baly, i, 266,

8vo, Lond. 1838, 1st edition.

182 LYMPHATIC SYSTEM.

After thus being convinced that the use of one branch of
the system is to absorb, we cannot at first sight but wonder
that any anatomist should have hesitated to attribute a similar
office to the other. Nevertheless, some anatomists have been
led to ascribe to the lymphatics a very different use to what
they found the lacteals perform ; particularly since the time
that Nuck first made his experiments, in which he thought he
injected these lymphatic vessels from the arteries, and there-
fore concluded that they had no other use than as correspond-
ent veins to return the lymph from such arteries as were too
small to admit the red blood or the serum. And in this
opinion anatomists were confirmed by the theories of Leeuwen-
hoek and of Boerhaave, concerning the gradation in the series
of the globules of our fluids, and of the sizes of the vessels
destined to convey them ; thence the idea of the lymphatic
vessels being small veins continued from arteries became so
general amongst physiologists.

But although this idea was so commonly received, yet there
were some physiologists who reasoned better on the subject ;
and amongst the first of these was Glisson, who, in a book
published the very year after that in which Bartholin wrote
upon the lymphatics, attributes to those vessels the office of
carrying back to the blood-vessels the lymph which had lubri-
cated the cavities of the body.1

M. Noguez (LXXXIII *) likewise, in a chapter where he men-
tions the name of Dr. Glisson, speaks of the use of the lym-
phatics as follows : " Us reportent la lymphe dans les vaisseaux

1 De Hepate, cap. xlv, edit. Lond. 1654.

(LXXXIII*.) Dr. Simmons* stated that the main points at issue in
the controversy between Dr. Hunter and Dr. Monro, alluded to by Mr.
Hewson at page 120, were known long before to M. Noguez ; where-
upon Mr. John Hunterb insisted on his brother's claim to the dis-
covery of the office of the lymphatic vessels, observing that Noguez
entertained on the subject the erroneous doctrines of his day, and that
he did not in the least comprehend the absorbent system as Dr. Hunter
understood it. But, as mentioned in Notes LXV * and LXXXII, it is
now well known that absorption may take place in parts of the animal
body which have no lymphatic vessels.

a Life of Dr. William Hunter, p. 30, 8vo, logue of the Museum of the Royal
London, 1783. College of Surgeons, vol. ii, pp. 10-

b Extract from his MSS. in the Cata- 13, 4to, London, 1834.

LYMPHATIC SYSTEM; iss

sanguius ou dans les veines, il y en a dans toutes les parties
du corps, ils repompent la matiere lymphatique qui s'evacue
par les arteres, on peut les nommer conduits absorbans;" and
again, in another place, he says, " ils reyoivent la lymphe sub-
tile qui se repand sur la surface de toutes les parties, et dans
les differentes cavites du corps, ils la reportent au sang." ]

Hambergerus also seems to have had this idea of their office,
for he says, " ex omnis generis cavo, humidum liquidum ve-
hente, sive sit arteria, sive vas secernens, vel excretorium, vel
aliis usibus destinatum, vasa lymphatica oriuntur."2

Frederic Hoffman has been still more explicit on this sub-
ject, and has expressed the doctrine of the lymphatics being
absorbents very completely, in his Medic. Ration. System,
lib. 1, sect. 2, cap. 3, where he says —

" § 2. Duplex est origo vasorum lymphaticorum, quaedam
ex ipsis arteriis prodeunt, alia ex porosa et cellulosa partium
substantia nascuntur.

" § 4. Lymphatica, quse ex partium substantia oriuntur,
aquosi succi nutritii partem resorbent, ac revehunt ad cor.

" § 7. Revehunt vero omnia lymphatica ex universe cor-
pore lympham suam ad capsulam lumbarem et chyliferum due-
turn, in quam se exonerant.

" § 11. Ad facilitandum lymphae regressum vasa hsec val-
vulis instructa sunt, et quidem sigmoideis, numerosioribus et
angustioribus, quse quidem lympham libere transmittunt, impe-
diant tamen quo minus regurgitet."

This opinion of the lymphatics being a system of absorbents
has been adopted and supported with additional arguments,
first by Dr. Hunter (LXXXIV), and afterwards by Dr. Monro,

1 Anatomic de THornine, 2d edit. cap. viii. 2 Physiol. Med. $ 469.

(LXXXIV.) The following passage is interesting, as showing the state
even of Dr. Hunter's knowledge concerning the office of the absorbents
and some of the properties of the blood, in the year 1757. Speaking
of the erosion of the sternum and vertebrae in a case of aneurism of
the aorta, he says : " The appearance was rather as if the blood had
insensibly dissolved away the substance of the bone, making the
greatest havoc in the softest parts of the bone, as we see in stones of
unequal texture that have been long washed by a dropping, or stream
of water. Has the blood that property which some have ascribed to
it of dissolving bony matter ? A surgeon of my acquaintance, whose

184 LYMPHATIC SYSTEM.

who, besides showing the fallacy of the experiments brought
in favour of the common veins doing the office of absorption,
have advanced the following to prove that the lymphatics per-
form it.

First. Their great analogy with the lacteals, with which they
agree in their coats, in their valves, in their manner of ramify-
ing, in their passage through the lymphatic or conglobate
glands, and in their termination in the thoracic duct, and, in
short, in every circumstance with regard to their structure ;
and thence it is probable that they also agree with them in
their use. And as the lacteals are known to begin from the
surface of the intestines, and to be the absorbents of these
parts, the lymphatics may begin from the other cavities of the
body, and may absorb the fluids which had lubricated those
cavities.

Secondly. The passage of the venereal, variolous, and other
poisons into the constitution ; these poisons first making an
ulcer, and then being absorbed along with the matter of the
ulcer, and infecting the whole body. That in such cases they
are not absorbed by the common veins, but by the lymphatics,
appears from their inflaming these lymphatics in their course,
and by their generally inflaming a conglobate gland before
they enter the system; a strong argument in favour of their
being taken up by the lymphatic vessels, which pass through
these glands in their way to the thoracic duct.1

These two are the principal arguments by which the doc-
trine of the lymphatics being a system of absorbents has been
supported. Experiments made by injections in the dead body,
where such injections have been forced from the arteries into
the cellular membrane, and from the cellular membrane into
the lymphatics, have been likewise brought in favour of this

1 See Dr. Hunter's Medical Commentaries. See also Dr. Monro, De Vasis Lymph.
Valv.

experience, abilities, and veracity are unquestionable, told me, upon
my asking this question, that he had once opened a little tumour upon
the temple, that contained only pure blood, and that there was no bone
under it. He supposed that the blood had dissolved that part of the
skull upon which it lay."a

a Med. Obs. and Inq. by a Society of Phys, in London, i, 344-5, 8vo, 1757.

LYMPHATIC SYSTEM. 185

doctrine, but improperly, and being now given up by those
who advanced them,1 they need not be dwelt upon here.

But our experiments, related above, furnish another argu-
ment in favour of the lymphatics being a system of absorbents;
for, in chapter the seventh, we have mentioned that in these
experiments we have always found the fluids contained in the dif-
ferent cavities of the body and that contained in the lymphatics
exactly agreeing with one another, in their transparency, in their
consistence, &c. And in animals in health we likewise found,
when the one jellied on being exposed to the air, the other
did so too ; and in the animal reduced by low diet, where the
properties of the one were altered, those of the other were so
likewise, and exactly in the same manner (LXXXV). So that
we now seem to have obtained as decisive an argument in fa-
vour of absorption by lymphatics as we before had of that by
the lacteals ; fbr the lacteals were concluded absorbents from
their being found to run from the intestines filled with a fluid
similar to what was in the cavity of the gut ; so we seem here
to have the samfc reason for believing that the lymphatics ab-
sorb from cavities, because they are found to contain a fluid
exactly similar to what is observed in these cavities ; a strong
argument that the fluid had passed from such cavities into
these lymphatics by absorption.

Such then seems to be the purpose for which the lymphatic
vessels were provided, that is, to do the office of absorption, an
office of the greatest- importance to the animal : no wonder,
therefore, that there should be a system set apart for perform-
ing it, and not only in man and quadrupeds, but also in birds,
fish, amphibious animals, and perhaps even in insects of the
most perfect kind.

1 See Dr. Hunter's Medical Commentaries, p. 57.

(LXXXV.) See Notes LXVIII, LXIX and LXXI.

CHAPTER XI.

AN EXAMINATION OF THE OPINION WHETHER SOME OF THE
LYMPHATIC VESSELS MAJ NOT BE CONTINUATIONS OF THE
SMALL ARTERIES.

I HAVE already observed that, soon after the discovery of
the lymphatic vessels, Glisson and others suspected that they
arose from the cavities of the body to take UJD the fluids ex-
haled from the blood-vessels ; but, at the same time, another
opinion was entertained by some anatomists, namely, that a
part of the lymphatics were reflected from the small arteries to
which they corresponded, in the same manner* as the common
veins belong to the arteries carrying red blood.

In this opinion, that the lymphatics were only veins, anato-
mists were confirmed from experiments made by injections,
particularly the blowing air into the arteries of the kidney,
spleen, &c., and seeing it return by the lymphatics ; 1 a fact
that has since been proved to be owing to the air having burst
from the arteries into the cellular membrane, and so having got
into these vessels, and therefore by no means proving a direct
communication between those arteries and the lymphatics.2

Other injections, likewise, such as mercury, water, &c., hav-
ing been thrown into arteries, and afterwards having got into
the lymphatics, have been mentioned as so many proofs of a
direct communication ; but greater experience with injections
has convinced some of the more accurate amongst later anato-
mists of there likewise being a fallacy in these experiments ;
or of the fluids having got from the arteries into the lympha-
tics, not by passages which were natural to the living body,
but by such as were the eifects of laceration in the dead one.

1 Nuck, Adenog. cap. iv, vi.

2 See Professor Monro, De Venis Lymph. Valvul.

LYMPHATIC SYSTEM. 187

The present Professor Monro has distinguished himself in this
subject; from his observations1 and those of Dr. Hunter,2 the
notion of the lymphatics being continued from arteries seems
to be very fairly exploded. And it is made probable that the
injections in dead bodies had misled their predecessors, who
had not been sufficiently aware that these injections might
possibly have passed, not by natural, but by forced passages.

CHAPTER XII.

ON THE STRUCTURE OF THE VILLI OF THE INTESTINES, AND THE
MANNED IN WHICH ABSORPTION IS PERFORMED.

THE term villi, applied to the very small processes of the in-
ternal coat of the intestines, conveys an improper idea of their
figure in the human body. In many quadrupeds indeed they
are cylindrical, or like hairs or wool ;3 but in the human sub-
ject they are broad and flat ; and when viewed with a microscope

1 De Ven. Lymph. Valv. 2 Medical Commentaries.

3 I have seen them of that shape in the dog, cat, lion, and the ass (LXXXV *).

(LXXXV*.) Of the intestinal villi, Professor Miiller* observes, " It
is true that they are flattened in most mammalia, as in the rabbit, dog,
and hog ; but in the calf, ox, and sheep, many of the villi are cylin-
drical ; and sometimes, as in the sheep and ox, the flattened villi are
more numerous in one part of the intestines, in another part the cylin-
drical ; and in the two last-named animals, particularly in the sheep,
the villi in many parts of the intestines are flattened and broad, with
cylindrical tips. By the villi becoming broader at their base, and be-
ing connected with each other so as to form folds, a gradual transition
is established from the villi of mammalia to the rugae or folds by which
they are replaced in many birds and in reptiles. This transition is some-
times perceptible in the intestines of one and the same animal." He
adds, that the villi, especially those of the cylindrical form, contain a
simple cavity, which he has observed in the calf and ox ; and, with the
assistance of a microscopic examination by Henle, in the human sub-
ject. Professor Wagner b made the interesting observation that the villi
in the human small intestine differ in shape at different periods of life.

a Physiology, tr. by Dr. Baly, 1st edit. b Physiology, tr. by Dr. Willis, pp. 323-4.
pp. 267-8.

188 LYMPHATIC SYSTEM.

they look like the valvulse conniventes in miniature, or are small
folds of the internal coat : so the accurate Lieberkiihn has
painted them.1

The whole surface of the alimentary canal is covered with
these processes ; but in the large intestines they are so very
short, that to 4he naked eye the surface of these intestines
appears smooth; thence the learned Albinus has considered
them as having no villi,2 which is true in one sense only, viz.
that their inner coat does not appear -shaggy, but spongy or
cellular; yet the partitions between these cells are similar in
structure to the villi of the small intestines.

The appearance of the villous coat is very different in dif-
ferent parts of the alimentary canal.

In the oesophagus the villi are small and not so full of ves-
sels, and are of the cylindrical or conical shape.

At the upper part of the stomach the villous coat appears in
a microscope like a honeycomb, or like the reticulum, or
second stomach of a ruminant quadruped in miniature ; that is,
full of small cells, which have thin membranous partitions.
Towards the pylorus these partitions are lengthened so as to
approach to the shape of the villi of the jejunum.

The villi of the jejunum are thin folds considerably broader
than they are long, and when not injected they, are very flat,
so as to resemble valvulse conniventes in miniature, but are so
small that they can but just be distinguished by the naked eye.

In the ileum the villi become rather longer in proportion to
their breadth. In the colon and rectum the villous coat is like
the upper part of the stomach, honeycombed or cellular.
These facts are only evident after a minute injection; for in the
uninjected state the villi collapse, so that their figure cannot be
distinguished. The partitions between the cells of the internal
coat of the colon and of the stomach being each very vascular,
and agreeing with the villi of the jejunum in every circum-
stance except magnitude, are to be considered as having the
same use, namely, to absorb, as will appear probable hereafter.

Upon each of the villi is an artery and a vein which make
a network of branches, as is well expressed in the ingenious
Lieberkiihn's plate.3

1 De Villis Intestin. tab. i. 2 Annotat. Academic, lib. vi, cap. viii.

3 De Villis Intestinorum, tab. i, icon. 2.

LYMPHATIC SYSTEM. 189

Besides arteries and veins, it is probable that the villi have
nerves distributed to them.

They likewise have lacteals, which, according to Lieberkiihn,
open on the extremities of the villi, sometimes by one and
sometimes by more orifices (see Note LXXXIII).

Each villus, the same author thinks, has an ampullula, into
which these orifices lead, and from the other side of the ampul-
lula the lacteal passes through the coats of jthe intestines. This
is the only circumstance concerning these parts in which I
should differ from this very accurate observer, whose experi-
ments in support of his opinion about this ampullula seem to be
liable to fallacy. Of this I was first persuaded from observa-
tions made on fish, birds, and amphibious animals, in all of
which I can demonstrate that the villi have a network of
lacteals as well as a network of arteries and veins.1

That the villi in some fish have a network of lacteals, I
have distinctly seen in the turbot, where I have injected the
lacteals with .mercury, which readily runs from those vessels
into the villi, and makes them turgid and erected. In the
same way, I have likewise seen a network of lacteals on the
villi of a turtle, where these villi are of a different shape, and
in some parts of the gut are cellular, or honeycombed, some-
thing like the lower part of the human stomach, only the par-
titions of the cells are here much larger.

In birds the experiment is more difficult, because their lac-
teals are full of valves, and their villi are small compared to
those of the turbot ; nevertheless, I have succeeded in getting

1 An account of some preparations exhibiting these facts was printed in the Phil.
Trans, vol. lix. (LXXXVI.)

(LXXXVI.) At the College of Surgeons, in Lincoln's inn-Fields,
there is a small box, marked on the lid, " Mr. Hewson's Microscopical
Preparations of the Intestinal Villi," but in which there is now only
one portion of small intestine left.

The circumstantial observations in the text on the intestinal villi of
the turbot and turtle seem to have been completely overlooked. Pro-
fessor Miiller,a after stating that something similar to villi may be seen
in a few fishes, remarks that Retzius has described in a serpent " pro-
cesses of the mucous membrane of the intestine, which resemble villi,
and can scarcely be anything else, although Rudolphi has said that
fishes and reptiles have no true villi."

» Physiology, tr. by Baly, vol. i, p. 267, 1st edition.

190 LYMPHATIC SYSTEM.

the valves to give way, so as to fill a few of the lacteals dis-
tinctly enough to be seen to divide into branches upon the
villi, and therefore to prove that they do not form a bag or
ampullula.1

Since therefore a network of lacteals is found upon the villi
of all these animals, from analogy we should suspect the same
in the human subject, whose villi are of the same shape, that
is, broad and flat, which figure would appear not a proper one
for an ampullula.

The experiments from which the ingenious Lieberkiihn was
persuaded there was an ampullula, were first, the villi appear-
ing turgid with milk which had curdled in them, in such sub-
jects as had taken milk just before their death.2 But whoever
has made experiments with injections must be convinced of its
being difficult to distinguish clusters of small vessels from bags,
when these vessels are not filled with fluids of a brighter
colour than milk or chyle ; and even in those cases where such
vessels were filled with vermilion (which is so much more vivid
and distinguishable) some anatomists have been misled ; par-
ticularly concerning those corpora globosa in the kidney, which
have been considered as bags or cryptse. But I have re-
peatedly observed, and have now by me some preparations
which prove that these corpora globosa are not uniform bags,
but convoluted arteries, which comes near to the idea that
Ruysch had of them (LXXXVII). Some ingenious anatomists
have warmly espoused a contrary opinion, and have not only
supposed the kidney to have follicles, but most other glands of
the body, particularly the breast or mamma, and the salivary
glands. But that they likewise have been deceived by a clus-
ter of small vessels will appear probable when we consider that
the corpora globosa in the kidney, which have by so many

1 See Philos. Transactions, vol. lix, p. 213.

2 De Villis Intestinorum, § 2, 3.

(LXXXVII.) Mr. Bowman has given an excellent account of the
structure and use of the Malpighian bodies of the kidney, with obser-
vations on the circulation through that gland. See * Philosophical
Transactions/ 1842, Part I, pp. 57 et seq. Among some of Hewson's
preparations at the College of Surgeons, are two good injections of these
glomeruli in the kidney of the lion and of the ass.

LYMPHATIC SYSTEM. 191

been pronounced bags or follicles, are only small vessels clus-
tered together or convoluted. And on making a variety of
experiments on these other glands, I think it evident in what
manner the deception has happened to those ingenious anato-
mists ; namely, when the excretory ducts of the breast, for ex-
ample, are injected with vermilion and painter's size, the small
acini of which that gland consists are made extremely red,
and such a preparation being dried, the acini appear as large
as pins' heads, so that the breast has been suspected to have
follicles of that magnitude ; but on injecting the breast with
mercury, which is a brighter substance, and better contrasted
to the dried fibres, I have distinguished what in the other pre-
paration might be mistaken for a bag, was here evidently no
more than the extremity of the excretory duct, terminating in
one of these acini, and dividing into a number of branches so
suddenly as to come near "to Ruysch's description of the peni-
cilli of arteries ; but the small branches, into which this extre-
mity of the duct divided, were so close to one another, that in
the preparation where they were filled with size and vermilion,
they could not be distinguished, but in that where they con-
tained mercury, it evidently appeared that in each acinus of the
magnitude of a pin's head, there was a considerable number of
branches, but so small as not easily to be seen with the
naked eye (LXXXVIII).

The ingenious Lieberkiihn has mentioned another experi-
ment, from which he was not only persuaded that the lacteals
formed an ampullula upon the villi, but that this ampullula was
filled with a spongy substance. This experiment he made by
inflating the villi by the arteries and the veins, and upon dry-

(LXXXVITI.) That the roots of the milk-ducts are little cells or vesi-
cles, typifying a like structure in a whole series of glandular organs, is
now a well-known fact. Professor Miillera has noticed the observa-
tions made on this subject in the hedgehog, as early as 1751, by
Duvernoi. Mr. Cruikshankb proved the existence of this structure
in the human breast ; and Mascagni, according to Miiller, observed,
in 1819, the absence of any direct communication between the vesicu-
lar ends of the milk-tubes and the blood-vessels. Sir Astley Cooper
has given an admirable description of the Anatomy of the Human
Breast, 4to, London, 1840.

a On the Structure of the Glands, tr. hy b Anatomy of the Absorbing Vessels,
Mr. Solly, p. 9, 8vo, Lond. 1839. p. 209*, 2d edit. 4to, Lond. 1790.

192 LYMPHATIC SYSTEM.

ing the intestine and cutting the villi across he observed them
spongy.1 But this is an appearance which may be as well ex-
plained, from knowing that each villus contains a network of
small arteries and veins, which being inflated might occasion the
villi to assume a spongy appearance.

Since then the experiments from which the villi of the
human subject were supposed to contain an ampullula are so
equivocal ; and since the villi can be proved in the other classes
of animals, viz. in birds, fish, and the amphibia, to have net-
works of lacteals as well as of arteries and veins, the probability
is in favour of their having the same structure in the human
subject. But the difference between us is inconsiderable ; for
it may be nearly the same thing whether there is a bag filled
with sponge, or a plexus of vessels.

I have some preparations by me adapted to the microscope
in Lieberkiihn's manner, in which I think I can clearly show
the orifices of the lacteals on the extremities of the villi, where
there appears, as he has described, sometimes to be one, and
sometimes more orifices.2 My preparations were made by in-
jecting into both arteries and veins a thin size or glue, coloured
with vermilion ; when this was not pushed to great minute-
ness the villi appeared exactly as Lieberkiihn has painted them,
with a network of arteries and veins on each, and when ex-
amined with a microscope no orifices could be distinguished,
but each villus appeared to have a smooth edge. Yet in some
part of the ileum where the injection had run more minutely,
the villi appeared erected, and instead of being broad and thin
were more round and cylindrical, and the extremity seemed
spongy and porous, whilst all the sides of the villus were per-
fectly smooth and uniform. And moreover as in these prepa-
rations the orifices only appeared when the villi were completely
erected, I think this circumstance points out the use of the
villi..

It might be here objected that these were only lacerations
of the villi, but I am persuaded they were not, from having, on
repeatedly examining them, observed the pores or orifices very
distinct and empty ; whereas, were they lacerations, I think I
should have seen the injection in them, as the villi were so
much distended by it.

1 De Villis Intest. § 8. 2 Ibid. § 3 (See Notes LXXXIII and LXXXVI).

LYMPHATIC SYSTEM. 193

It has long been observed by physiologists that absorption
takes place only in living animals, and not in the dead ; for if an
intestine in a dead animal be filled with milk, none of that
milk will get into the lacteals ; but in the living animal, the
milk will readily be absorbed. This I think may be explained
from what is above observed of the orifices of the lacteals ap-
pearing to open when the villi are erected, something like
which may take place in the living animal ; that is, whenever
absorption is to be performed the blood-vessels of the villi may
become turgid, and the orifices of the lacteals may then stand
rigidly open, and be capable of attracting, like capillary tubes
made of hard substances. But in the dead body the villi being
emptied of blood, the coats of the lacteals being soft collapse,
by which means their orifices are closed, and they are thence
made incapable of attracting the chyle, or of absorbing.

It is observable that those parts of the skin which are in-
tended to have more sensibility than the rest, have those pro-
cesses called villi most remarkably ; this is evident, when after
a minute injection we compare the tips of the fingers, the lips,
the glans penis, with other parts of the skin ; and this is still
more observable in the tongue, whose papillae are the instru-
ments of taste. In these instances some physiologists have
suspected that the blood-vessels were some way subservient to
the nerves for sensation, an opinion which I think is very pro-
bable ; and the use of the villi of the skin, agreeably to their
opinions, seems to be as organizations of vessels to become
more turgid at particular times, by which turgescency the ex-
tremities of the nerves are made more capable of doing their
functions; and agreeably to this idea it is observable that when
we attempt to taste anything extremely grateful, the papillae
of the tongue can be seen to become erected.1

And as those villi of the skin seem to be organizations

1 The papillae of the tongue in the human subject appear to the naked eye, when
they are not minutely injected, quite smooth, but on a minute injection each of these
papillae appears covered with small vascular processes or villi ; so that in such a
tongue every one of the papillae seems in the microscope like a bunch of fibres, or
rather like a sheaf of corn ; some preparations of which, adapted to the microscope,
I have now by me. The learned Albinus seems not only to have observed this, but
to have had the same idea of the use of these processes, which he calls tubercles, and
has painted them like those little eminences that appear upon a nipple, but I find
them much longer. See his Annot. Acad. lib. i, cap. xv.

13

194 LYMPHATIC SYSTEM.

capable of that turgescency which is necessary to adapt the
sentient extremities of the nerves to receive impressions, so I
suppose the villi of the intestinal tube are able to exert a similar
erection or turgescency, in order to make the small absorbents
stand rigidly open, and thereby act like capillary tubes of glass
or other hard substances : and perhaps such membranes as the
pleura, peritoneum, &c. may be without villi, because such pro-
cesses would be less proper for affording the smoothness of sur-
face required for the motion of one viscus upon another ; but
to answer the same purpose they may have a network of blood-
vessels surrounding the absorbing pores^ which reticulation, by
its turgescency, may make the pores stand rigidly open as those
we have observed upon the villi (LXXXVIII*). But this being
a less perfect organization, and used here, merely because the
more perfect, or villous, would be incompatible with the mo-
tion of the viscera upon those membranes, may, for that rea-
son, be more liable to fail in doing its office, and thereby
occasion dropsies of those parts ; nothing like which seems to
happen to the villi, which do not, as far as we know, ever
fail in absorbing chyle so as to occasion a disease.

The orifices of the lacteals and lymphatics, therefore, by
acting as capillary tubes, in consequence of a particular organiza-
tion near their beginnings, are capable of absorbing the chyle
and lymph ; and as a capillary tube of glass being put into a
basin of water will attract the water to a considerable height
above the surface of that fluid, so the animal tubes or ab-
sorbents, merely by their attractive power, may not only im-
bibe but convey the fluid at least as far as the first pair of
valves, whose distance from the orifice of the absorbents is pro-
bably very small. But whether the force of attraction extends
much farther than the first pair of valves may be a question.
Some have suspected that these fluids were propelled forwards
principally by this attraction, but it is not necessary to admit
such a supposition, in order to explain the motion of the chyle,
or of the lymph, because the vessels which convey these fluids
are believed to have muscular fibres, which being stimulated by

(LXXXVIII.*) As mentioned in Notes LXXXII and LXXXIII, this doc-
trine of absorption is now exploded. The serous membranes are co-
vered with smooth pavement-epithelium.

LYMPHATIC SYSTEM. 195

the fluid may contract peristaltically, and press the fluid for-
wards from one pair of valves to another.

The lymphatic system is very full of these valves, much more so
than the venous, and the reason of this difference seems to be,
that the blood in the venous system is strongly pressed forwards
by the vis a tergo from the action of the heart and arteries, and
therefore its course is less liable to be interrupted by any acci-
dental pressure. But the motion of the absorbed fluid in these
vessels having no such force, but only that of the attraction at the
orifice, and the peristaltic contraction of the coats, might easily
be overcome by any lateral compression, were it not for the
valves, which seem to be given to prevent the retrocession of
the lymph being considerable, and to make any lateral pres-
sure, instead of preventing, rather promote its passage to the
heart ; and as the lymphatic vessels in the human subject not
only accompany the arteries, but in many places pass under
them, when the course over them is as direct, it would seem
probable, as some physiologists have suggested, that this was
done in order that they may have the pulsation of such arteries
communicated to them, which pulsation, inconsiderable as it is,
may rather promote the passage of the lymph.

CHAPTER XIII.

CONTAINING SOME PATHOLOGICAL OBSERVATIONS RELATING TO
THE LYMPHATIC SYSTEM.

THE fluids which lubricate the different cavities of the body
are sometimes collected in these cavities in an extraordinary
quantity, and form dropsies, such as the ascites, anasarca,
dropsy of the pericardium, thorax, tunica vaginalis, &c.

In a former chapter we observed, when speaking of the
lymph that moistens such cavities, that its properties vary in
different circumstances; that in these dropsies the fluid that
is let out by tapping is generally as thin as water, and in-
stead of coagulating, when exposed to heat, only becomes a
little turbid. Sometimes indeed it agrees with the serum of
the blood in coagulating by heat, and sometimes it flows from
these cavities in a viscid or ropy state. In all these cases the
fluid occasioning the dropsy is different from the fluid that
naturally moistens those cavities, which, in experiments related
above, was found to agree with the coagulable lymph of the
blood, in the circumstance of jellying merely by exposition to
the air.1

These circumstances being considered, I think we may

1 The water in the ventricles of the brain should, I believe, be excepted, as I
never saw it jelly, even when exposed to heat (LXXXIX).

(LXXXIX.) The fluid of a blister, when let out and set aside, fre-
quently coagulates spontaneously : see the careful observations by Dr.
A. Buchanan, in the ' Proceedings of the Philosophical Society of Glas-
gow/ No. 7 ; and note to the English edition of Gerber's 'Anatomy/
p. 105. As observed in Notes LXVIII and LXIX, the fluid of the lym-
phatic vessels and of the pericardium does not always coagulate sponta-
neously when taken from healthy animals. The effect of heat on some
fluid from the vaginal tunic of the testicle is mentioned in Note xvn j
and the coagulation of that fluid, at the temperature of the air, when
mixed with serum of blood or with some other substances, in Note xviu,
p. 31.

LYMPHATIC SYSTEM. 197

thence be led to a more correct notion about the causes of
those dropsies, which causes have been supposed to be either
an increased secretion, or an impeded absorption, or a rupture
of the lymphatic vessel ; none of which probably, strictly speak-
ing, gave rise to such morbid collections of water. For if
merely an increased secretion or an impeded absorption was
the cause of an ascites or an anasarca, then the fluid let out
should resemble that contained in these cavities in living ani-
mals. The same reasoning holds good against these dropsies
being occasioned by the rupture of a lymphatic vessel ; that is,
the fluid evacuated is not similar to what we found contained
in those vessels in our experiments, where the lymph jellied on
exposition to the air.

And as we observed in those experiments, that these fluids
approached nearer to the nature of those found in dropsies, in
proportion as the animal was weakened, or reduced, as particu-
larly in the dog fed eight days on bread and water, is it not
therefore more probable, that in these kinds of dropsies there
is something more than an increased secretion, or an impeded
absorption? that is, there is a perversion of the secretion, or
the vessels throw out a flui.d different from the natural one;
which may happen, either from the exhalant arteries being
themselves altered by disease, so as to change the properties
of the fluid which passes through them, or from the mass of
blood being vitiated or abounding so much with water as to
affect this secretion j thence these dropsies are not primary dis-
eases, but the consequences of others, and a diseased liver,
spleen, or lungs, which so often accompany these dropsies, are
not so properly to be considered as giving rise to them by
causing a rupture of a lymphatic vessel, or obstructing the
course of the lymph, as by affecting chylification and sanguifi-
cation ; for when the liver, for example, is diseased, and the bile
deficient in quality or in quantity, the food not being properly
assimilated, may make a bad blood, which may affect the
vessels, and may let go its water into these cavities.

But although from these considerations it seems probable
that an obstruction or rupture of the lymphatics is not the
cause of these dropsies, where a mere water is found in those
cavities, yet they may occasionally be the causes of others. If
a lymphatic should burst in a person in health, a dropsy may

198 LYMPHATIC SYSTEM.

ensue ; but the fluid would possess the properties which that
lymph does naturally, and be either found coagulated, or would
be capable of coagulation, when let out ; the same may be ob-
served of an increased secretion, or of an obstruction of a
lymphatic vessel ; the fluid would differ from mere water, and
would either coagulate or be viscid. Instances of such fluids
sometimes occur in dropsies.

Thus a viscid ropy fluid has been let out of the abdomen,
not only in the dropsy of the ovarium, in which such a fluid is
commonly met with, but likewise sometimes in the ascites in
men.

In like manner, the cellular membrane is sometimes filled
with a gelatinous fluid, which does not ooze out when the in-
teguments are scarified, nor does it retain the impression on
being pressed with the finger, as in the common anasarca ; this
was remarkable in a woman that was in St. George's Hospital
a few years ago, and who at the same time had an obstruction
of her menses, but no other symptom of ill health. The legs
in this woman were swelled to twice their ordinary size, but
did not pit on being pressed with the finger. A case of the
same sort may now be seen in one of the nurses at St. Bartho-
lomew's Hospital.

A similar gelatinous fluid is sometimes seen upon cutting
into tumours of the rheumatic kind near the ligaments of the
joints ; and Dr. Lower observed, that it was common to find
the pericardium filled with a jelly in dead bullocks.

As we have remarked of a rupture of the lymphatic vessels
in an animal in health, that the fluid which escapes will co-
agulate, so we may observe of a wound of such a vessel, the
lymph which oozes from it, if the person be in health, will not
be a mere water, but will be like the coagulable lymph of the
blood in jellying on exposition to the air, only a little later than
the blood itself does, if we may judge from what is observed in
Chap, vii, pp. 157 et seq. A case of this sort I saw in a butcher,
who, by letting his knife fall upon his shin, cut some of the
large lymphatic vessels which pass over the tibia, as represented
at c c, Plate I, fig. 1. From this wound there flowed a consider-
able quantity of a clear lymph, which, being confined by the
dressings, jellied, and then, at first sight, appeared like a whitish
fungus, but being loose could be removed with a spatula.

LYMPHATIC SYSTEM. 199

Some cases of wounds of lymphatics are related by the late
Professor Monro,1 who describes a white fungus as apt to arise
from them ; but since seeing the case above mentioned, I can-
not help suspecting that, notwithstanding the accuracy of that
gentleman, he had met with a deception of this sort. My
patient, like his, was cured by tight pressure, and lint dipped
in a solution of vitriol.

When a blister is applied to a person not much weakened
by disease, as for example, behind the ear for the toothache, or
to one who labours under a violent fever or an inflammation,
we find, on removing the cuticle, a serous fluid discharged.
This fluid, I have found, coagulates by heat, exactly like the
serum of the blood, or the white of an egg. After this serous
fluid is let out from the blistered part, we sometimes see over
the inflamed skin a white crust or jelly, which is easily re-
moved, and seems to be the coagulable lymph of the blood,
which has been thrown out by the inflamed exhalant arteries,
and had jellied amidst the serum. When this jelly is more
condensed, it appears not much unlike a second cuticle.2

It is a fact universally admitted by physiologists, that all
parts of the human body are bibulous, or imbibe fluids applied
to them ; thus, garlic applied to the skin is soon smelt in the
breath, and turpentine rubbed upon any part of the body
soon gives to the urine a violet-like smell. In like manner,
poisonous substances are sometimes taken into the constitution.
The variolous matter, inserted under the skin by the point of
a lancet, produces the smallpox, and the venereal matter, in-
troduced by a chancre, occasions the lues venerea. These facts
have been long known, but it is still a question by what chan-
nels these substances enter the body, whether by the common
veins, which have most generally been suspected to absorb, or
by the lymphatic vessels (see Note LXXXII).

How little probability there is of the common veins doing
this office has been observed above ; but there are many cir-
cumstances which prove that the lymphatic vessels perform it ;
and there are some appearances in diseases which cannot
otherwise be well accounted for.

For example; after the insertion of the variolous matter

1 Med. Essays, vol. v, art. xxvii.

2 In dropsical cases the fluids discharged by blisters are more watery.

200 LYMPHATIC SYSTEM.

under the skin of the arm, in inoculation, before that matter
enters the constitution so far as to produce any fever or eruption,
the lymphatic glands in the axilla most frequently swell or
inflame ; a strong presumption that it is through the channel of
the lymphatic system that this poison enters the constitution.

After the application of the venereal matter to the genitals,
where the skin is abraded, before the lues venerea is occa-
sioned, there is commonly an inflammation of the inguinal
glands, which circumstance renders it probable, that in this
case, too, the poison enters by the lymphatic vessels.

On the application of blisters, we sometimes find lymphatic
glands swelling between the part inflamed by the blister
and the heart.1 Thus the axillary glands sometimes become
painful from a blister between the shoulders; and I once
from this cause saw glands swell where they are not commonly
met with on dissection. It was in the case of my ingenious
friend, Mr. H. Apothecary, who, having applied a blister to his
back, observed some small swellings opposite to the inferior
costa scapulae ; he showed them to me, and I told him they
were glands inflamed in consequence of an absorption of a part
of the cantharides, and would subside on drying up the blister,
which accordingly happened.

It may be worth remarking, that these cases of glands swell-
ing in consequence of the application of blisters, furnish the
strongest arguments in favour of the lymphatics being the in-
struments of absorption ; because where a blister is applied, the
skin is only inflamed and not eroded, so that if the acrid mat-
ter gets into the lymphatic system, it can only be by absorp-
tion. Whereas, when the variolous matter is inserted with a
lancet, or the venereal matter enters from a chancre, we might
question whether it got into the lymphatics by absorption or
by an erosion of the side of those vessels. But when the lympha-
tic glands swell in consequence of a blister, it seems deci-
sive in favour of the poison entering the lymphatic system,
merely in consequence of that system being endowed with a
power of imbibing whatever is applied to the surfaces of the
body.

Poisons which enter the constitution, besides being disco-
vered by their affecting the lymphatic glands, can sometimes

1 See Professor Monro, De Yen. Lym. Valv. p. 93.

LYMPHATIC SYSTEM. 201

be traced by their effects on the lymphatic vessels. A case of
this sort, in consequence of the bite of a gnat, was lately ob-
served by my ingenious friend, Dr. Maddocks, physician to
the London Hospital. This patient, as Dr. Haddocks informs
ine, had been weeding in a garden, and had been bit near the
root of her thumb, where a painful tumour appeared. Soon
after which one of the axillary glands inflamed and swelled,
and from the tumour of her thumb to the axilla, the ascent of
the matter could be traced by a painful ridge or cord, which
went on the fore part of the cubitus, and inside of the arm,
exactly in the situation of the lymphatic vessels shown in
Plate IV, fig. 2, ff, h, one of which seemed to be inflamed in
consequence of the absorption of the poisonous matter.

I have likewise lately seen the gland just above the inner
condyle of the os humeri, as is represented Plate IV, fig. 2, d,
swelled in consequence, of a wound and suppuration on the back
of the middle finger.

In ulcers of the legs, the matter is sometimes absorbed and
carried up the lymphatics, till it arrives at the glands in the
groin, where it occasions a bubo ; which bubo, as has already
been observed at page 129, differs from the venereal one in
being at the lower part of the groin, viz. in the glands, f, f}
Plate I, fig. 1.

I have even seen the matter of an issue in the leg produce
such a bubo by absorption, and in this case too the matter
could be traced by a painful line in the inside of the thigh in
the course of the lymphatic vessels, represented in the same
plate.

Matter formed in the joints, on being absorbed, likewise
produces such buboes.1

And milk which has stagnated in the breast creates a painful
swelling in the axillary glands.

The axillary glands are likewise frequently observed to swell
in consequence of cancers in the breast ;2 and it is found to be
of no use to extirpate the breast itself, unless the infected glands
can likewise be removed; for otherwise the cancerous humour
left in the glands may renew the disease; and indeed when
these glands are affected in consequence of a cancer, the ope-
ration of extirpation must be very precarious, as we can never
1 See Dr. Hunter's Medical Commentaries. 2 Monro, De Ven. Lymph. Valv. p. 92.

202 LYMPHATIC SYSTEM.

be certain that the matter which has got so far as these glands
may not also have got a little further, and have entered the
constitution.

In cancers of the lips, the lymphatic glands under the angle
of the lower jaw, and on the side of the neck, are apt to swell
from the same cause, viz. the absorption of the cancerous mat-
ter. And the like swellings may be produced by the absorption
of the venereal virus from sores in the lips. I have seen these
glands swell in consequence of gum-boils, which frequently ap-
pear on the upper jaw, from the fang of a rotten tooth making
its way through the jaw, and producing a suppuration that
sometimes bursts outwards, sometimes into the socket of the
tooth, and sometimes disappears without rupture; in which
case I have several times seen the glands under the angle of
the lower jaw swell and become painful, during the few days
that the boil was diminishing.

In short, wherever there is an erosion or ulceration of the
body attended with acrid matter, that matter is apt to be ab-
sorbed, and in passing into the constitution commonly inflames
the lymphatic glands which lie between the part eroded and
the thoracic duct; a fact well deserving the attention of the
surgeon, who might otherwise take these glandular tumours
for primary diseases, and might expect to cure them without
attending to the ulcers themselves, but in vain ; for being oc-
casioned by the absorption of acrid matter, they will remain so
long as the matter continues to be absorbed; but that matter
being once removed, these glandular tumours will generally
subside of course.

And moreover, as it frequently happens that these poisons
are not immediately absorbed, but remain for some time in the
wound before they enter the vascular system, it gives us an
opportunity of preventing the disease by cutting out the morbid
flesh, and thereby extirpating the poison before absorption has
taken place ; a practice that has been used successfully for the
bite of a mad dog, and cannot be too strongly recommended,
as it seems to be the only certain way of preventing the ill
consequences of such an injury. In those cases where the knife
cannot be used, the application of the actual or potential cau-
teries has been recommended ; for these cauteries, by destroying
the poisonous matter, and the parts which it has already tainted,

LYMPHATIC SYSTEM. 203

may preserve the constitution from the infection. It is also
probable that the venereal poison might be prevented from
entering the constitution, if immediately upon the appearance
of a chancre the patient would submit to the excision of that
chancre, or to have a caustic applied to it. In like manner,
since it is known that when the cancerous matter is once ge-
nerated, whether in the mamma, testis, or any other gland, that
such matter, on being absorbed, will infect the other parts of
the body ; is it not therefore a strong argument in favour of the
early extirpation of cancers, that the longer they are suffered
to remain, the more probability there will be of the cancerous
humour being taken up by the absorbents, and spreading the
infection ?

As the lymphatic vessels pass through the lymphatic glands
in their way to the thoracic duct, when these glands are ob-
structed, the lymph, not being able to get into that duct, is
retained in the extremities ; thence we so often see dropsies the
consequences of diseased lymphatic glands ; which dropsies can-
not be cured till the obstruction of the gland be removed. But,
as I have already observed, the lymphatic vessels do not con-
stantly pass through glands, but some of them pass by their
sides ; thence it is possible that a gland may be perfectly ob-
structed, and yet the lymph may get by the collateral branch
of a lymphatic into the thoracic duct, and not be retained in
the extremity so as to occasion a dropsy or redema. In like
manner, a gland may be perfectly eroded, or may be cut out,
sometimes without the lymph being thereby prevented getting
into the thoracic duct. And it may also happen, that the ve-
nereal or other poison may, upon being absorbed, pass into
the constitution by one of these lateral branches without en-
tering a lymphatic gland or inflaming it. That this is probable
the reader may believe, upon looking over the plates, parti-
cularly Plate II, where the mercury appears to have passed
from the groin the whole length of the trunk without entering
a lymphatic gland. From which fact may be understood how
the venereal poison sometimes enters the constitution, and
produces the lues without occasioning a bubo, an instance of
which I saw lately. And the variolous matter introduced by
inoculation, although frequently producing inflammation and
swelling of the lymphatic glands, yet is not always attended

204 LYMPHATIC SYSTEM.

with those symptoms : to which may be added, that another
reason why these poisons do not constantly affect the lymphatic
glands in their way into the body, may be the lessened sen-
sibility of these glands in some particular cases ; whence the
same poison which at one time would have produced the worst
effects, may at another pass through these glands without in-
flaming them.

And lastly, not only obstructed lymphatic glands sometimes
occasion dropsies, but also whatever impedes the passage of the
lymph into the veins ; whether it be a thickening of the coats
of the jugular or subclavian veins near the termination of the
thoracic duct, or a tumour of the aneurismal, scirrhous, or
encysted kind, contiguous to any part of the lymphatic system ;
for such tumour, by compressing the lymphatic vessels, may
prevent the return of the lymph, and may thereby occasion a
dropsy or oedema of the parts from which these vessels originated.

Upon the whole, whoever carefully views the lymphatic sys-
tem must be convinced that, as it explains and points out the
cure of many diseases, it deserves the attention of the practi-
tioners of the healing art. And as it is so generally diffused
through the animal kingdom, it strongly claims the regard of
those who wish to inquire philosophically into the animal eco-
nomy, especially as, by the knowledge of this system, we are
now flattered with the hopes of ascertaining the use of the
lymphatic glands, the thymus, and the spleen ; which discoveries
are to be the subjects of the Third Part of these Inquiries.

EXPERIMENTAL INQUIRIES.

PART III.
A DESCRIPTION

RED PARTICLES OF THE BLOOD

IN THE

HUMAN SUBJECT AND IN OTHER ANIMALS ;

AN ACCOUNT OF THE STRUCTURE AND OFFICES OF THE LYMPHATIC GLANDS,
OF THE THYMUS GLAND, AND OF THE SPLEEN :

THE REMAINING PART OF THE OBSERVATIONS AND EXPERIMENTS

OF THE LATE

MR. WILLIAM HEWSON, F.R.S.

AND TEACHER OF ANATOMY.

BY MAGNUS FALCONAR,

SURGEON, AND TEACHER OF ANATOMY.

LONDON :

MDCCLXXVII.

Nullius addictus jurare in verba magistri,
Et verum et veri cupio cognoscere causas.

HOR.

TO

WILLIAM BROMEIELD, ESQ.

SURGEON TO HER MAJESTY, AND TO ST. GEORGE'S HOSPITAL;

AHD TO

PERCIVAL POTT, ESQ., F.R.S.

AND SURGEON TO ST. BARTHOLOMEW'S HOSPITAL,

THE FOLLOWING SHEETS ARE MOST HUMBLY INSCRIBED,

AS A TRIBUTE OW GRATITUDE AND RESPECT,

BY THEIR MUCH OBLIGED

AND VERY HUMBLE SERVANT,

THE EDITOR.

PREFACE.

THE following sheets comprise the remaining part of the
discoveries and experiments of my late friend Mr. William
Hewson, in whose death the public sustained an almost irre-
parable loss ; the loss of a genius, whose superior abilities in
his profession rendered him eminently conspicuous among his
cotemporaries, and I have no doubt will transmit his fame to
posterity, enrolled among the highest names of antiquity. But
to the men of science of this age, his talents require no com-
mendation from my pen.

Unfortunately for the world, his death prevented him from
completing the work he had begun : the first chapter of this
treatise only was written by him, and read in the Royal Society,
June 17th and 24th, 1773; which was afterwards published in
the second part of the sixty-third volume of the Philosophical
Transactions ; and it is much to be lamented, that among his
papers we have not found the smallest note upon the subject
of the other four chapters. But a three years' acquaintance,
during the greatest part of which the strictest intimacy and
friendship subsisted between us, afforded me numberless oppor-
ttmities of discoursing with him upon this subject, and of
making myself perfectly acquainted with his ideas ; besides
which, as I had the advantage of assisting him in other anato-
mical pursuits, it was frequently my good fortune to make and
repeat many of the experiments; by which means I became
not only better acquainted with the doctrine, but also perfectly
confirmed in my knowledge of its truth.

As far as I can recollect, I have recited the experiments in
the order they were made by Mr. Hewson ; but lest I might
err, or not represent facts in their true state, I have repeated
all the experiments frequently since his death, and have written
them circumstantially as they appeared to me. But to make

14

210 PREFACE.

these experiments with the attention and circumspection neces-
sary upon so curious a subject, requires more time than my
other employments would permit, on which account I have
been obliged to defer the publication of them till this time,
when I hope their greater accuracy will in some measure com-
pensate for my delay.

I have chosen to publish them under the form of chapters
and sections, for the sake of more precision for those who are
not much conversant in anatomy; at the same time I natter
myself this method will not be wholly unacceptable to those
who have made that branch of natural philosophy their parti-
cular study : for as the facts are numerous, by this method
they will be referred to with much greater facility, and the
propriety of the inferences will be judged of the more readily.

To such gentlemen as are not well acquainted with ana-
tomy, the subject, from the quantity of new matter it contains,
may appear obscure ; but as this is a doctrine in which not
only the medical part of the world, but philosophers in general,
are much interested, we most earnestly entreat them to sus-
pend their judgment till they have deliberately considered all
the facts. The inductions will then, I presume, be thought just.

As it is the ultimate end of philosophy to investigate truth,
so it must afford the greatest pleasure to generous minds to
embrace it, in whatsoever form they find it. The remarks
and criticisms of such I shall esteem the greatest obligations.
Some there may be who, having early imbibed prejudices, will
find it very difficult to shake them off; others may be very
unwilling to believe that they have erred both in opinion and
practice all the preceding part of their lives. I shall at all
times esteem it a happiness and an honour to remove the
doubts of these gentlemen, not so much from a wish to per-
suade by argument, as to convince by demonstration.

And as many gentlemen who are not possessed of glasses
may be desirous of seeing the experiments upon the blood, I
shall at all times be happy in showing them to such gentlemen
as will do me the favour of calling upon me.

KED PARTICLES OF THE BLOOD.

CHAPTER I.

ON THE FIGURE AND COMPOSITION OF THE RED PARTICLES OF
THE BLOOD, COMMONLY CALLED THE RED GLOBULES.

THE red particles of blood in the human subject have, since
the time of Leeuwenhoek, been so generally allowed to be
spherical, that in almost all books of physiology they are de-
nominated red globules (xc). A few authors, however, have,
at different times, doubted whether they were spheres, and
amongst the rest Father de la Torre, whose curious observa-
tions, together with his glasses, were presented to the Royal
Society, anno 1766.

It is a curious and important fact, that these particles are
found so generally through the animal kingdom, that is, they
are found in the human species, in all quadrupeds, in all birds,
in all amphibious animals, and in all fish, in which animals
they are red, and colour the blood.

The blood even of insects contains particles similar in shape
to those of the blood of more perfect animals, but differing in
colour (xci).

(xc.) Senaca first mentions them as spherical, and subsequently
states that, far from being little spheres, their shape is lenticular, com-
paring them to lentils. But the corpuscles were commonly considered
to be spherical in Hewson's time, and even long afterwards. The error
is hardly now completely discarded.

(xci.) An account of Mr. Newport's observations on " The Develop-
ment of the Blood-Corpuscle in Insects and other Invertebrata, and its
Comparison with that of Man and the Yertebrata," will be found in the
* Proceedings of the Royal Society/ Feb. 6, 1845. A paper was read

a Traite de la Structure du Coeur, torn, ii, pp. 81, 656, ed. 1749.

212 RED PARTICLES

In water insects, as the lobster and shrimp, these particles
are white ; in some land insects, as the caterpillar and grass-
hopper, they appear of a faint green when in the vessels, as I
am persuaded from experiments. I have seen them in an in-
sect no bigger than a pin's head, and suspect they exist almost
universally through the animal kingdom.

What is so generally extended through the creation, must
be of great importance in animal economy, and highly deserv-
ing the attention of every inquirer into the works of nature.

before the same Society, June 19, 1845, by Mr. Wharton Jones, "On
the Blood-Corpuscle considered in its diiferent phases of development
in the Animal Series."

Mr. Newport states that the matured blood-corpuscles in the in-
vertebrata are always oat-shaped, or oval, but change their form when
removed from the body. They commence as minute rounded molecules,
which are gradually developed into nucleated oat-shaped corpuscles,
within which nucleoli are formed. These corpuscles he regards as
analogous to the white corpuscles of vertebrata. When matured they
become diffluent, liberate their nucleoli, and supply plastic fluid to the
blood. Nearly the whole of these corpuscles disappear in this way in
lepidopterous insects, during the first few days of the pupa state, when
the organic changes are most active, and very few remain in the perfect
insect. From these observations, Mr. Newport, like the physiologists
cited in Note cxviu, regards the blood-corpuscle as analogous in func-
tion to the secreting cells of glands. The further development of the
nucleoli into discs, as stated in his paper, he is now satisfied is incorrect.

Mr. Jones recognizes three phases in the development of the blood-
corpuscle, which he respectively names the phase of granule-cell, the
phase of nucleated-cell, and the phase of free cellseform nucleus. In
the invertebrata and oviparous vertebrata, the blood-corpuscle ex-
ists only in the first two phases. It is found in all the three phases
only in man and the mammalia. In the phase of free cellaeform nucleus
it is the well-known red corpuscle of man and the mammalia. The
red corpuscle of oviparous vertebrata belongs to the phase of nucleated-
cell. In the invertebrata the blood-corpuscle in the phase of nucleated-
cell does not attain a perfect coloured stage, as in the oviparous
vertebrata, but it may be met with slightly tinged red.

In the lymph of oviparous vertebrata there are granule-cells and
nucleated cells ; in the lymph of man and the mammalia there are, in
addition to these, free cellseform nuclei. In fact, as regards corpuscles,
the lymph of the vertebrata is identical with their blood, — the principal
difference being that, as regards the lymph of the oviparous vertebrata,
the nucleated cells have not attained to the perfectly red stage, whilst,
as regards the lymph of man and the mammalia, the free cellaeform
nuclei have not attained to their perfectly red stage. A more complete
account of Mr. Jones's views will soon be published in the ' Philosophi-
cal Transactions.'

OF THE BLOOD. 213

This subject becomes the more interesting, so much reasoning
in the theory of medicine being built on the properties of
those particles.

It is by the microscope alone that we can discover these
particles ; and as some dexterity and practice are required in the
use of that instrument, there have not been wanting men of
character and ingenuity, who, having been unsuccessful in their
own experiments, have questioned the validity of those made
more fortunately by others. Some have gone so far as to as-
sert that no credit can be given to microscopes; that they
deceive us, by representing objects different from what the}
really are (xcn).

These assertions, though not entirely without foundation,
when we speak of one sort of microscopes, are very unjustly
applied to them all. In compound microscopes, when the
object is viewed through two or more glasses, if these glasses
be not well adapted to the focus of each other, the figure of
the object may be distorted ; but no such circumstance takes
place when we view an object through a single lens. All who
use spectacles agree, that the figures of objects appear the same
through them, as they do to the naked eye. And as the single
microscope has, like the spectacles, but one lens between the

(xcn.) The differences in the results obtained by the use of the
microscope have often been cited, especially by Dr. Bostock, to
prove the inutility of this instrument in anatomical and physiological
inquiries. But, on the same principle, the use of the naked eye
might be objected to ; for there are observations made by it nearly or
quite as discordant as those which have resulted from the use of the
microscope. Let any one, for example, attend to the descriptions given
by various eminent men, who have used the naked eye only, of the inti-
mate structure of the bones, or of the filamentous and adipose tissues.
Yet these very subjects have been made so clear by the aid of the
microscope, that no anatomist is now likely to fall into the old error of
confounding these two last-named tissues, or, in distinguishing them,
to find it necessary to have recourse to the evidence of remote physio-
logical and pathological phenomena. "With the microscope, too, Harvey
could have shown a direct proof of his great discovery of the circula-
tion of the blood, which took so much time to establish by inference
from observations with the naked eye. A curious collection might be
formed of the errors of anatomical observations made by the naked eye
compared with the errors which have arisen from the use of the micro-
scope.

214 RED PARTICLES

eye and the object, there is no reason to suppose the one can
deceive us more than the other. The compound having a
larger field, is more pleasant than the single microscope for
many purposes ; but the single should be always preferred by
those who wish to ascertain the figures of minute bodies. It
was this instrument, supported on a scroll, as delineated by
Mr. Baker (Microscope made Easy, plate 2, chap, ix), that has
been used in these experiments, and almost all the observa-
tions were made with lenses, as they are prepared by some of
our more skilful workmen in London. One observation only
was made by means of those globules made of glass, which the
ingenious Father de la Torre presented to the Royal Society,
and which they were so obliging as to lend to me. Of these glo-
bules, two only were fit for use when they came to my hands ;
viz. that which, according to Father de la Torre, magnifies the
diameter of the object 640 times, and that which magnifies
1280 times. The lenses of the greatest magnifying power
made in London, are those of ^ of an inch focus ; which, even
allowing eight inches to be the focal distance of the naked
eye, magnifies the diameter of the object only 400 times ; a
power much inferior to what may be obtained by globules, and
particularly by that globule which, according to Father de la
Torre, magnifies the diameter 1280 times ; and this globule I
have used in some of these experiments. But our lenses,
though inferior in magnifying power to these globules, are
much superior in distinctness. The globules are full of clouds
made by the smoke of the lamp used in preparing them, and
the object can be seen only through the transparent parts of
the globules, which makes it difficult to get a satisfactory view
of it ; this, with the trouble of adapting the object to the focus
of the glass, made me prefer our own lenses for all the experi-
ments mentioned in these sheets, except one; and it is but
doing justice to the ingenious gentleman above mentioned, to
acknowledge that the greater power of his glasses was found,
in that experiment, more than to compensate for their want of
distinctness.

These particles of the blood, improperly called globules, are
in reality flat bodies ; Leeuwenhoek and others have allowed
that in fish, and in the amphibia, they are flat and elliptical,
but in the human subject and in quadrupeds almost all micro-

OF THE BLOOD. 215

scopical observers have agreed in their being spherical (xcin).
When we consider how many ingenious persons have been
employed in examining the blood with the best microscopes, it
will appear wonderful that the figure of these particles should
have been mistaken ; but our wonder will be lessened when we
consider how many obvious things are overlooked, till our at-
tention is very particularly directed to them ; and, besides, the
blood in the human subject and in quadrupeds is so full of
these particles, that it is with great difficulty we can see them
separate, unless we find out a method of diluting the blood.
It is to such a discovery that I attribute my success in this
inquiry; for having examined the blood as it flows from the
vessels of the human body, it appeared a confused mass, not-
withstanding I spread it thin on a glass, or a piece of talc.
It then occurred to me to dilute it, but not with water, for
this I knew dissolved the particles, but with serum, in which
they remained undissolved (xciv). By the serum I could dilute
it to any degree, and therefore could view the particles distinct
from each other ; and in these experiments I found that these
particles of the blood were as flat as a guinea (xcv). I like-

(xcin.) See Note xc.

(xciv.) Muysa mentions the difference between the effect of serum
and water on the corpuscles. That they are not dissolved by water was
observed by Dr. Young.5 It merely deprives them of their colouring
matter, leaving undissolved the pale membranous base of the disc, and
the nucleus also, when there is one ; see Note en, pp. 222-3 : and for
an account of the action of water, and fluids of different densities, on
the blood-corpuscles, with a description of their power of endosmose and
exosmose, see the observations by Dr. Rees and Mr. Lane.c The cor-
puscles should be examined in their own serum ; for it may be difficult
to distinguish their outline in the serum of another animal, which is
apt to cause them to aggregate into clumps. The serum of the horse
has this effect remarkably on the corpuscles of many mammalia ; the
addition of a small quantity of salt to the serum will diminish or destroy
the clumping of the corpuscles : see Notes xxiu and cxi.

(xcv.) They are not nearly so thin, in relation to their breadth, as
a guinea, the thickness of which is about a nineteenth of its diameter.
Dr. Hodgkin and Mr. Lister/ indeed, state the thickness of the blood-
corpuscle to its diameter as 1 to 45 ; but this must be a misprint.
From measurements of the thickness, at the circumference, of the

a Musculorum Artificiosa Fabrica. 4to, c Guy's Hospital Reports, 1841, vol. vi;

Lud. Batav. 1751, p. 100. and 1843, vol. i.

b Medical Literature, 8vo, Lond. 1813, d Philosophical Magazine, or Annals, &c.

p. 547. vol. ii, 1827, p. 133.

216 RED PARTICLES

wise observed, that they had a dark spot (xcvi) in the middle,
which Father de la Torre took for a hole ; but upon a careful
examination I found it was not a perforation, and therefore
that they were not annular. I next made experiments by
mixing these particles with a variety of other fluids, and ex-
corpuscles of several mammalia/ I find that it is generally between one
third and one fourth of the diameter ; and the average thickness of the
human blood-corpuscle 1 estimate at j^i^^th of an English inch, and
the diameter at ^-g^th. These proportions are shown by the figures in
the * London and Edinburgh Philosophical Magazine' for Aug. and Sept.
1842, pp. 109, 170. More than a century ago, Jurinb estimated the
diameter of the blood-corpuscle of man at ^-^ ^th of an English inch ;
and Senac,c afterwards, at ^-gV^th and -jg-Vo^h of a French inch ; all, I
have no doubt, most accurate measurements of a great number, though
not of the majority, of the corpuscles in any drop of human blood.
According to Senac,d the English physicians regarded the corpuscles as
hollow on both sides ; which he disbelieved, concluding, I think, like
many of the old observers, only from what he saw in the lower vertebrate
animals. But in man and the mammalia generally, it is certain that
many of the corpuscles have, like a biconcave disc, a depression on each
side of the broad surface ; as inferred by Dr. Young,6 and proved by
Dr. Hodgkin and Mr. Lister. f Some of them are without the depression,
and quite flat ; a few may even be slightly swoln on the broad surfaces,
and still more so at the edges, so that their relative thickness is variable.
This doubly convex form is very remarkable and general in the cor-
puscles of young embryos. Varieties in the form of the corpuscles are
mentioned in Notes cvi and ex ; the size and form of the corpuscles in
different animals, in Notes xcvm and cxvu ; and the central spot of
the corpuscles, of mammals, in Note xcvi.

(xcvi.) The central spot of the blood-corpuscle of mammalia should
not be confounded with the nucleus of the blood-corpuscle of oviparous
vertebrata, described in Note en. The central spot is not visible in
the best focus and light ; then, if the object-glass of the microscope be
so slightly removed from the corpuscles as not to destroy the distinctness
of then* contour, a dark spot will appear in their centre ; if the glass be
next so far moved towards the corpuscles as to place them slightly
within the focus, the dark spot will become bright ; and when in a
clear light the spot is altogether invisible, it may be instantly brought
into view by diminishing the light, without altering the focus. Senacg
described the centre of the frog's blood-corpuscle as sometimes white
and sometimes black ; and Delia Torreh depicted a like variation in the
centre of the corpuscles of mammalia, though he mistook it for a hole.

a See the Tables at the end of this e Med. Liter, p. 546, 8vo, Lond. 1813.

chapter, Note cxvm*. f Phil. Magazine, 1827, vol. 2, p. 132.

b Phil. Trans. 1718, vol. xxx, p. 762. s Traite du Cceur, ed. 1749, torn, ii, pp.
c Traite du Cosur, torn, ii, p. 655, ed. 656-7 ; and 2d ed. torn, ii, p. 277.

1749; and 2d ed. torn, ii, p. 276. hNouveOsservazioneMicroscopiche,tab.
d Op. cit. torn, ii, p. 80, ed. 1749. xiv, figs. 3, 4, 4to, Napoli, 1776.

OF THE BLOOD. 217

aniined them in many different animals; and the result of
these experiments was, that their size is different in different
animals (xcvn), as is seen in Plate V, where they are repre-
sented of the size they appeared to my eye, when viewed
through a lens of ± of an inch focus; which, allowing eight
inches to be the focal distance of the naked eye, magnifies the
diameter ] 84 times.

It may not be improper to observe here, that the accurate
Leeuwenhoek, not having diluted the human blood or that of
quadrupeds so as to see these particles separate from each
other, was thence not qualified to describe them from Ms own
observation, as he has done those of fish and of frogs, and
suspecting a round figure was more fit for circulating in our
vessels, was thence led to suppose these particles spherical in
the human subject. But I shall hereafter be able to show
from his own words, that it is not his observations, but his
speculative opinions, or his theory, that differ from what I have
discovered by these experiments.

In Plate V, it appears that of all the animals which I have
examined, the particles are larger in the fish called a skate;
next to a skate they are larger in a frog and a viper, and other
animals of this class ; they are somewhat smaller in the com-
mon fish, as the salmon, cod, and eel. In birds they are smaller
than in fish ; in the human subject smaller than in birds ; and
in some quadrupeds still smaller than in the human subject.
Leeuwenhoek, speaking of their size, says, he is confident the
red particles of the blood are no larger in a whale than in the
smallest fish.1 And others have since his time said, they are
of the same size in all animals ; but it is evident from com-
paring their size as delineated in the above-mentioned plate,
that it differs considerably, and that they are not larger in the
largest animals; for we find that in an ox they are not so
large as in a man, and so far are they from being larger in
the whale than in the small fish, it appears probable, from
comparing their size, as delineated Plate V, fig. 2, from a por-

1 Cons. Arcan. Nat. p. 220.

(xcvir.) Concerning the shape and size of the corpuscles of man and
different animals, see Notes xcv and xcvin, and the Tables of Measure-
ments, Note ex viii*, pp. 236 et seq., at the end of this chapter.

218 RED PARTICLES

poise, which belongs to the same genus as the whale, that they
are smaller in those animals than in fish ; neither is their size
inversely as in the size of the animal, for they are as large in
an ox as in a mouse (xcvui). The difference in their size,

(xcvm.) Among the mammalia, the harvest mouse, the smallest
British species, has corpuscles quite as large as those of the horse ;
and in the common mouse they are larger than in the ox or horse.
The corpuscles of the elephant are larger than those of any other
mammal ; the sloth has them next in size, and then comes the whale,
in which they are somewhat larger than in man, the capybara, and the
porpoise. The Napu musk-deer has the smallest corpuscles yet dis-
covered ; those of the Stanley musk-deer are about the same size ;
in the ibex (Capra Caucasica) they are rather larger, and in the goat
slightly larger still. The corpuscles of the goat were the smallest
known before my observations, referred to in Note cxvin*, p. 236.

Although in mammals there is not much relation bet ween the size of
the corpuscles and that of the animal in different orders, there is such
a connexion in any one natural family. The corpuscles of the large
ruminants or rodents, for example, are larger than the corpuscles of
the smallest species. In the intermediate series there are several
slight exceptions, but no considerable one. Yet in different subdivisions
of one order the size of the corpuscles may differ so remarkably, that
the fact will probably be available as a help to classification. Thus the
ferae, if set down according to the size of their blood-corpuscles, would
stand as follows, — seals, dogs, bears, weasels, cats, viverras ; and
one of the last may generally be distinguished, simply by the smaller
size of its corpuscles, from any species of the three first-named families.
Among genera of doubtful affinities, if regard were paid only to the size
of the blood-corpuscles, the hyaena would be arranged with the canidae,
basaris with the ursidae, and cercoleptes with the viverridae. The fox
has slightly smaller corpuscles than the dog. Though the smallest
corpuscles are found in the ruminants, some of the largest species of
this order have larger corpuscles than many carnivora, or than the
horse. The camel tribe are the only mammals with oval blood-discs,
like those of lower vertebrata in shape, but entirely agreeing in size and
structure* with the corpuscles of mammalia. The blood-corpuscles of
marsupial animals agree generally in form, size, and structure, with the
corpuscles of the corresponding placental animals. In the monotre-
mata, according to the observations of Dr. Davy,b Dr. Hobson and
Dr. Bedford,0 the corpuscles are similar, in all respects, to those of
man ; my measurements of the corpuscles of the echidna are to the
same effect.

In birds and reptiles, with a few exceptions, the long diameter of the
oval blood-corpuscle is rather less than twice the short diameter.
These proportions used to be considered as universal; but the long

a See Note en, pp. 222-3. c Tasmanian Journal, vol. i, p. 94, Van-

b Proc. Royal Society, May 28, 1840. Diemen's Land, 1841.

OF THE BLOOD. 219

therefore, depends on some other circumstance than a difference
in the size of the animal.

As to their shape, I have already mentioned that they are
flat in all animals, even in the human subject ; of which any
one may be convinced by repeating the following experiments.

EXPERIMENT I.

Take a small quantity of the serum of human blood, and
shake a piece of the crassamentum in it till it is coloured a

diameter may be either thrice, or scarcely one and a half of the short
diameter; and it is remarkable that these differences of shape may
occur in the corpuscles of nearly alhed genera, as explained in the
* Proceedings of the Zoological Society,' 1840, pp. 43, 132; and J842,
p. 110. The short diameter of birds' corpuscles is commonly about
the same as the diameter of the circular corpuscles of mammals. The
size of the blood-corpuscles of mammalia in connexion with that of the
animal, is described in a former part of this note'. Throughout the
entire class of birds, the law for the size of the corpuscles is very nearly
the same as in a single family of mammals. At least my measurements,
given at the end of this chapter, afford but few if any examples of com-
paratively large corpuscles in the smallest species, and of more minute
corpuscles in the largest species of birds. In a humming bird, Dr. Davy*
found the average length of the corpuscles 2^VstD» and the breadth
•joV otn of an inch. These corpuscles are therefore shorter than those,
yet examined, of any other bird. In my Tables of Measurements in
this class, it will be observed that the blood-corpuscles of that great
bird, the cassowary, are the largest, while the smallest corpuscles
occur in some of the little insectivorous and granivorous birds, and
in a few of the smallest species of the gallinaceous order.

In the naked amphibia the blood-corpuscles are generally larger than
in any other animals ; and largest of all in the amphibia with perma-
nent gills, as discovered by Professor Wagner, b and confirmed by my
measurements of the corpuscles of the siren.

The blood-corpuscles of fishes are noticed in Note cxvn ; the thickness
of the corpuscles of mammals, and their comparative size and shape in
the embryo, in Notes xcv and cxvi ; the structure of the corpuscles of
mammalia and lower vertebrata, in Note en ; the central spot, in
Note xcvi ; the shape of the nucleus in oviparous vertebrata, in
Notes cv and cxvn ; irregularities in the figure of the corpuscles of
mammals, in Notes cvi, ex and cxi ; and the blood-corpuscles of in-
vert ebrat a, with the corpuscle in its different phases of development in
the animal series, in Note xci. For the copious Tables of Measure-
ments, see Note cxvm*, at the end of this chapter, pp. 237 et seq.

a Proceedings of the Zoological Society, b Physiology, tr. by Dr. Willis, p. 236 ;
March 24, 1846. and Proc. Zool. Soc. 1837, p. 107.

220 RED PARTICLES

little with the red particles ; then with a soft hair pencil spread
a little of it on a piece of thin glass, and place this glass in the
microscope, in such a manner as not to be quite horizontal,
but higher at one end than the other, by which means the serum
will flow from the higher extremity to the lower ; and as it flows,
some of the particles will be found to swim on their flat sides,
and will appear to have a dark spot in their middle (see Note
xcvi) ; others will turn over from one side to the other, as they
roll down the glass. No person who sees them turn over can
doubt of their being flat ; he will see them, in turning, have
all the phases that a flat body has ; first, he will see them on
one side, then rise gradually on the edge, and turn over to the
other side. I have in this way shown their figure to a number
of curious persons, and particularly to many students of ana-
tomy, who have attended lectures in London within the last
six years. If instead of serum the particles should be diluted
with water, containing rather more salt than serum does, or if
instead of human blood that of an animal with larger particles
be used, then they will sometimes be seen not only flat, but a
little bended, like a crooked piece of money.

These experiments not only prove that the particles of the
blood are flat, and not globular, but likewise, by proving that
they are flat, they show that they are not fluid, as they are
commonly believed to be (xcix) ; but, on the contrary, are
solid, because every fluid swimming in another which is in
larger quantity, if it be not soluble in that other fluid, becomes
globular. This is the case when a small quantity of oil is
mixed with a larger quantity of water, or if a small quantity
of water be mixed with a large one of oil, then the water ap-
pears globular ; and as these particles are not globular but flat,
they must be solid, a circumstance that will appear still more
evident from future experiments.

It is necessary to remark, that in a few minutes after the

(xcix.) Hallera says of them, "Solidi, perpetui, circumscripti, certa
magnitudine et figura, certa ferri portione prsegnantes, in fluido in-
visibili moventur." Senac,b too, considered the corpuscles as solid :
see Note cvm.

a Elementa Physiologiae, torn, ii, p. 52. b Traite du Coeur, torn, ii, p. 665, ed, 1 749 ;
4to, Lausannse, 1760. and ed. 1774, t. ii, pp. 278, 283.

OF THE BLOOD. 221

particles are spread out on a glass, they run in clusters, and
stick to each, other, and then they appear confused (c).

When one of these particles is attentively examined, while
separate from the rest, it appears, as it lies on its flat side, to
have a dark spot (ci) in the middle, and round that dark spot
it is more transparent. This dark spot was believed to be a
perforation, or the particle was supposed to be a hollow ring,
by the ingenious Father de la Torre. But I find from a great
number of experiments, that the dark spot is a solid particle
contained in a flat vesicle, whose middle only it fills, and whose
edges are hollow, and either empty or filled with a subtile fluid.
This will be evident to every one who will carefully make the
following experiments.

EXPERIMENT II.

Take a drop of the blood of an animal that has large particles,
as a frog, a fish, or what is still better, of a toad ; put this blood
on a thin piece of glass, as used in the former experiment, and
add to it some water, first one drop, then a second, and a third,

(c.) Further on,a Hewson says he has seen them laid one against
another like a number of coins ; and the way in which the corpuscles
of mammalia run together by their broad surfaces, forming piles like
rolls of money, has become well known since the clear description of
the fact by Dr. Hodgkin and Mr. Lister. b The earliest representation
which I have seen of these rolls of the corpuscles is that by Delia Torre,c
three years after the publication of llewson's observations. Mr. Wharton
Jonesd has figured the rolls ; and I have depicted6 parts of them on a
larger scale, from the blood of man and of the horse. These rolls fur-
ther coalesce into clumps in bufly human blood, and still more remark-
ably in the naturally buify blood of the horse : see Note xxni. The
aggregation commences as soon as the blood is drawn, goes on after two
or three minutes at a greatly accelerated rate, and subsequently some of
the corpuscles separate again from the piles. Dr. Davyf has particularly
described the viscid quality of the corpuscles as distinct from that by
which they form into columns ; they stick together at their rims, so
that the corpuscles, when separating from each other, become elongated
almost into a fibre, and recover their circular form when completely
detached. I have frequently observed these appearances in corpuscles
which have been kept a day or two in the serum.

(ci.) See Note xcvi, p. 216.

a See Note cix, p. 228. * Edin. Med. and Surg. Journ. Ix, 311.

b Phil. Magazine, 1827, vol. ii, p. 135. e Lond. and Edin. Phil. Mag., Aug. and
1 Xuove Osservazione Microscopiche, Sept. 1842, pp. 109, 170.

tab. xiv, fig. 4, 4to, Napoli, 1776. f Trans. Royal Soc. Edin., xvi, 54-5.

222 RED PARTICLES

and so on, gradually increasing the quantity ; and in proportion
as water is added, the figure of the particle will be changed
from a flat to a spherical shape. When much water is added,
the vesicle will by degrees become thinner and more transpa-
rent, and will at last be dissolved. When the vesicle has thus
assumed a spherical shape, it will roll down the glass stage
smoothly, without those phases which it had when turning over
whilst it was flat ; and as it now rolls in its spherical shape,
the solid middle particle can be distinctly seen to fall from side
to side in the hollow vesicle, like a pea in a bladder. Some-
times, indeed, instead of falling from side to side, the solid
middle particle is seen to stick to one part of the vesicle ; and
in proportion as the vesicle, instead of being flat, assumes a
spherical shape, its longest diameter is shortened, as might be
expected on the supposition of its being hollow and flat (en).

(en.) The figures of Leeuwenhoek* indicate the nucleus in the cor-
puscles of the salmon and flounder. Bidloob called the corpuscles
globosee vesiculse. Emanuel Weisc inferred that the circumference
both of the oval and round corpuscles must be bounded by a membrane ;
and he speaks of the nucleus as a distinct part. Hewsou's demonstra-
tion of the nucleus and envelope in the corpuscle of the lower vertebrata
is good ; but I believe he erred in stating that a similar nucleus exists
in the human blood-corpuscle.

The majority of the red corpuscles in man, and other mammalia, after
an early stage of intra-uterine life, have no nucleus corresponding to
that so obvious in the corpuscles of the lower vertebrate animals ;d and
even the oval corpuscles of the camelidse agree with the corpuscles of
other mammals in this respect. But in the very young embryo of mam-
mals the blood-corpuscle has a distinct nucleus, the true representative
of the permanent nucleus in the corpuscle of lower animals ; and the
blood of such embryos at the earliest period is pale, from an abundance
of free globules like the nuclei, as noticed in Dr. Carpenter's Report,
' British and Foreign Medical Review/ vol. xv, p. 273.

Professor Owene is surprised that Messrs. Delpech and Coste were
ignorant of Mr. Hunter's claim to the discovery that it is a pale or
colourless blood that first circulates in the embryo of a red-blooded
animal. Yet this discovery was certainly made as early as 1654, for
Glissonf knew of it ; so did Needham,g and some of his successors in
the first half of the last century.

When the blood-corpuscle of mammalia is deprived of its colouring

* Select Works, tr. by Sam. Hoole, vol. d See Notes cxxxvn and cxxxix.

ii, pi. 17, fig. 26-8. 4to, Lond. 1807. e Hunter's Works, vol. iv, p. xiii, 8vo,
b Anatomia Human! Corporis, tab. xxiii, Lond. 1837.

f. 16, Fol. Ams. 1685. f Anat. Hepat. p: 411, 8vo, Lond. 1654.

c Acta Helvetica, torn, iv, pp. 355-56, £ De Formato Fcetu, pp. 72-3, 12mo,

4to, Basiliae, 1760 ; torn, v, 1762. Lond. 1667.

p. 348.

OF THE 'BLOOD. 223

After this experiment has been made on the blood of such
animals as have large vesicles, it may be made on human blood,
where the water will be found to have the same effect ; the
vesicles will become spherical, the diameters of these spheres
will be less than the largest diameter of the vesicle in its flat
state.

It is remarkable that more water is in general required to
produce this change on the vesicles of the human blood than
on those of frogs, or other amphibious animals ; and those of

matter by repeated additions of water, the membranous base of the disc
is left pale, pellucid, thin, flat, about two thirds as large as the un-
changed red corpuscle, and often not visible without the aid of sublimate
or iodine. This colourless base has been described by Sir Everard
Home,* and by Dr. Rees and Mr. Lane,5 as the nucleus of the red
corpuscle of man. When the corpuscle of the oviparous vertebrata is
washed with water, the envelope and nucleus both remain, perfectly dis-
tinct from each other, the nucleus being the thickest, much the smallest,
and very plain. If a layer of the corpuscles of mammalia be quickly
dried on glass, preserving their form, and then moistened by the breath,
the envelopes will become pale and pellucid ; but no nuclei appear.
Treat some corpuscles, no matter how minute they may be, of an
oviparous vertebrate animal in the same way, and the nuclei will be
seen through the envelopes as distinctly as any microscopic object can
well be. The shape of the nucleus is described in Note cv ; and more
particular details on all these points, with illustrative figures, will be
found in Wagner's ' Physiology,' translated by Dr. Willis, pp. 239-41 ;
and in the 'Lond. and Edin. Phil. Mag/ Aug. 1842, pp. 107 et seq.

Granular spots, either circular or variable in form and size, often
occur in the blood-disc of a mammal in consequence of a puckering of
the envelope, shrinking in one part and swelling in another, from a
variation of the contents of the corpuscle. Similar appearances, some
of which look very like a nucleus, may also be observed by adding
dilute muriatic acid or saline solutions to the blood under the microscope :
see Note cxi. Some of the deviations from the regular appearance of
the corpuscles are noticed in Notes cvi, ex, and cxv; and in the Appendix
to the English edition of Gerber's 'Anatomy,' pp. 9-11. Of the con-
tents of the corpuscles, De Blainvillec observes, "Les globules seraient
formes d'une petite vessie pleine d'une fluide analogue au vehicule, et
dans lequel se trouverait la matiere colorante ; et chacun de ces globules
en renfermerait d'autres plus petits, quoique de m£me structure ; c'est
P opinion de M. Raspail, qui compare alors les globules du sang a ceux
de la fecule de pomme de terre." See the interesting observations of
Mr. John Queckett on the blood-discs and their contents.d

:| Pliil. Trans. 1818, pp. 173-74. c Cours de Physiologic gen. et comparee,

'» Guy's Hospital Reports, 1841, vol. vi, torn, i, p. 209, 8vo, Paris, 1829.

p. 383. '' Microsc. Journ. p. 67, 8vo, Lond. 1841.

224 RED PARTICLES

the amphibia require still more than those of fish, for the sub-
stance of these vesicles being thicker, and more coloured in
man and in quadrupeds, than in the amphibia, is therefore later
in being dissolved in water ; and being thinnest in fish (cm),
it thence most readily dissolves. Those who are desirous
of repeating these experiments, had best begin with the blood
of toads and frogs, whose vesicles are large, and remain some
time without dissolving in the water (when that is used with
the above-mentioned precaution) ; by which means any one
accustomed to microscopical experiments may readily be satis-
fied of these curious circumstances.

From the greater thickness of the vesicles in the human
subject, and from their being less transparent when made
spherical by the addition of water, and likewise from their
being so much smaller than those of fish or frogs, it is more
difficult to get a sight of the middle particle, rolling from side
to side in the vesicle,1 which is become round; but with a
strong light, and a deep magnifier, I have distinctly seen it in
the human subject (civ), as well as in the frog, toad, and skate.

Since water makes these particles round, and makes the dark
spot in their middle disappear, it is evident the red particles of
the human blood are not perforated ; but that dark spot is
owing to something else than a hole ; and this is likewise con-
firmed, by observing that although the particle does, in an ob-
scure glass, appear only to have a dark spot, which might be
supposed to have a hole, yet with a very transparent lens, and
a good light, after diluting the blood with serum, that middle
part can be distinctly seen to be only of a deeper red than the
rest of the vesicle, and thence appears darker.

In these experiments, made by adding water to the blood,
the middle particles appear to be less easily soluble in water
than the flat vesicle which contains them : so that a little time

1 These experiments were all made with daylight, in clear weather.

(CUT.) The vesicle is certainly much more tender and evanescent
in fish than in birds or reptiles, as described in my paper on the blood-
corpuscles of British ophidian reptiles, * Proceedings of the Zoological
Society,' 1842, p. 108 ; but in the two last-named classes the vesicle has
generally appeared to me to be stronger and thicker than in mammalia.

(civ.) See Notes xcvi and en.

OF THE BLOOD. 225

after the proper quantity of water has been added, the flat ve-
sicles disappear, leaving their middle particles, which seem to
be globular and very small (cv).

That these red vesicles of the blood, although flat, are not
perforated, is evident, likewise, from a curious appearance which
I have repeatedly observed in blood that has been kept three
days in the summer season, until it was beginning to putrefy ;
the vesicles of this blood being diluted with serum, and examined
with a lens i of an inch focus (but more particularly when
examined with M. de la Torre's glass, which by his computation
magnifies the diameter 1280 times), were found to have become
spherical, the diameter of these spheres were less than their
largest diameter when flat, and their external surface was cor-
rugated in such a manner as to make them appear like small
mulberries (cvi).

I have seen the same appearance on mixing serum (that had
been kept three days in a warm place, and smelt putrid) with
fresh-drawn human blood; the vesicle assumed this globular
and mulberry-like appearance. In these experiments on human

(cv.) In birds, with some exceptions, the nucleus of the blood-
corpuscle, when exposed by acetic acid, is a longer oval than the un-
changed envelope. The nucleus of the corpuscle of oviparous verte-
brata is insoluble in water or in acetic acid ; but when soaked in
water the nucleus swells into a globular form, so as closely to re-
semble a lymph globule,* and retains that appearance for many days,
as shown in the ''London and Edinburgh Philosophical Magazine'
for August, 1842, p. 109, fig. 2. Hence the globular appearance which
Hewson notices in the nucleus, was probably caused by the action of
water.

(cvi.) Granulated, angular, and jagged .forms are very common in
the perfectly fresh blood of mammalia, especially in young animals.
I have commonly seen such altered corpuscles in the blood of puppies
and kittens just killed. These corpuscles are rather smaller than the un-
changed discs, and either irregular in shape, granulated throughout and
nearly globular, or slightly flattened and indented, often with minute
molecules attached. See Appendix to Gerber's 'Anatomy,' pp. 9, 10,
23, 24, 93, 99, fig. 268 ; where references are given to the observa-
tions of Dr. Barry on the spontaneous division of the blood-discs ; of
Mr. John Queckett on the parent discs throwing from their interior small
globular particles ; and of Professor Valentin on the minute granules so
arranging themselves as to form the envelope of the blood-corpuscle.

a See Note cxxn.

15

226 RED PARTICLES

blood beginning to putrefy I have likewise observed some of
these vesicles break into pieces, without becoming spherical,
and I have distinctly perceived the black spot in the centre
fissured through its middle, another proof that it is not a per-
foration.

In the blood of an eel, which was beginning to putrefy, I
have seen the vesicle split, and open, and the particle in its
centre come out of the fissure (cvn). As the putrefaction
advances, these vesicles which had become round spheres, or
like mulberries, and those which had been merely fissured, each
break down into smaller pieces : M. de la Torre seems to think
they have joints, and break regularly into seven parts ; and
Leeuwenhoek suspected these globules (as he called them)
were constantly made of six lesser globules.

But from observations I am convinced there is nothing re-
gular or constant in the number of pieces into which they
break. I have seen them fall into six, seven, eight, or more
pieces, by putrefaction ; for putrefaction breaks them down in
the manner it destroys other animal solids. I need hardly take
notice, that the small pieces into which the vesicles break are
equally red as the vesicle itself. The theory of the red globules
being composed of six serous ones, compacted together, and the
serous globules of six of lymph, has not the least foundation,
and is entirely overthrown by the simple experiment of mixing
the blood with six, or thirty-six, times its quantity of water ;
for the water dissolving the globules, ought to. reduce them to

(cvu.) When the hlood-discs of the lower vertebrate animals are
drying or dried on glass, and quite fresh, fissures often extend from
the circumference of the envelope to the nucleus. In the larger cor-
puscles, as of the toad and siren, I have counted many such fissures,
which, as well as the granular appearance which the corpuscles of
mammalia are prone to assume/ probably led to Leeivwenhoek's5 noted
fancy, that the corpuscles are formed of six globules, their union con-
stituting the red, and their separation the white part of the blood ;
this error was well disputed by Senac.c De la Torred depicted blood-
corpuscles as if cleaving to pieces by fissures.

a See Note cvi. c Traite du Coeur, torn, ii, pp. 91, 659,

b Opera Omnia, toin. iii, pp. 220-21, ed. 1749.

figs. 4, 6, 4to, Ludg. Bat. 1719 ; and d Nouve Osservazioni intorno la storia

Select Works, tr. by Samuel Hoole, naturale, tab. 4, figs. 3, 4, and tab. 5,

vol. ii, Part HI, p. 239, Plate xvii, fig. 16, 8vo, Napoli, 1763.
figs. 29,31', 4to, Lond. 1807.

OF THE BLOOD. 227

yellow serum or colourless lymph ;T but it does not ; on the
contrary, it is coloured red by these particles, even when used
in much greater proportion than thirty-six parts of water to
one of blood.

These red vesicles of the blood have not only been commonly
supposed globular and fluid, but they have with equal injustice
been imagined to be oily, and more inflammable than the rest
of the blood (cvm). That they are not oily, is evident from
their so readily dissolving in water, and that they are not more
inflammable than the rest of the blood is manifest, by burning
them after they are separated from the rest of the blood ; which
separation may be effected by shaking the crassamentum in
the serum, so as to diffuse the particles through it, and then
by pouring off the serum when they have subsided in it. I have
separated them in this manner, and compared their inflamma-
bility with that of inspissated serum, and of dried coagulable
lymph, and have not observed them more inflammable than the
serum or the lymph ; nor do they melt like oil, as some have
suspected, but burn like a piece of horn. Some authors who
have written on the figure of these vesicles in quadrupeds and
in the human subject, have expatiated on the great advantage
of their (supposed) spherical shape, in order for their more easy
circulation ; as it is probable that no form is preferable to a
spherical one for easy motion ; but as these vesicles are evidently
not spherical, but flat in all animals, we must believe that
nature has some good purpose to answer by making them of
that form.

It has been objected that, notwithstanding they appear flat
out of the body, they may possibly be globular in the body
while circulating ; and it has been said, that it is almost in-
conceivable that so many ingenious men should at different

1 See Gaubii Pathologia.

(cvm.) Senac and Haller, referred to in Note xcix, regarded them
as solid ; and Haller refuted the opinion of their discoverer, Malpighi,
that they are particles of oil ; but Senaca described them as formed of
sulphurous matter, burning and putrefying more quickly, and giving
out more volatile oil, than the rest of the blood. Gaubiusb considered
them as oily globules, like those of milk.

a Traite du Coeur, torn, ii, p. 81, ed. 1749 ; b Institutions Pathologiae Medicinalis,
and torn, ii, p. 275, 2d ed. §§ 280, 347, 8vo, Leid. Batav. 1758.

228 RED PARTICLES

times have viewed them through a microscope, and have con-
cluded them spherical, if they be really flat. But however that
may have happened, it is a fact that they are as flat in the body
as out of it. Of this I am convinced, by having repeatedly
observed them, whilst circulating in the small vessels, between
the toes of a frog, both in the solar microscope and the more
simple one above mentioned. I have seen them with their
sides parallel, like a number of coins laid one against
another (cix).

I have likewise, in that animal where they are elliptical, seen
them move with one end foremost, and sometimes with an edge
turned towards the eye. I have moreover seen them, when
entering a small vessel, strike upon the angle between it and
the larger trunk, and turn over with the same variety of phases
that they have when turning over upon a piece of glass.

Upon this occasion I may remark that it has been said by
some microscopical observers, that in passing through very
small vessels they seem to alter their shape, and to be
lengthened.

This conclusion I suspect has taken its rise from the observer
having seen them with their edge turned towards his eye, in
which case they would appear long and small, as if lengthened
by compression, especially to one who sets out with the notion
of their being globular. I have seen them, in blood-vessels
which would admit only single vesicles, move with difficulty, as
if straitened for room, but never saw them altered in their
shape by the action of the vessels (ex) .

(cix.) When the blood of a mammal is drawn, most of the corpuscles
soon run together so as to resemble a roll of coins ; only a few of the cor-
puscles are irregularly connected like a shapeless heap of money. It is
in this latter way that the oval corpuscles of the lower vertebrata and of
the camelidee connect themselves together, and not with the curious regu-
larity of the columns of the circular corpuscles of mammalia, mentioned
in Note c. Hewson appears to be describing the human blood-corpuscles
laid one against another like coins, because he is arguing for the flatness
of these corpuscles, which, as he previously states (p. 214), had been
long before known of the larger corpuscles of fishes and amphibia.

(ex.) The older observers, as Leeuwenhoek,a William Cowper,b and
Senac,c were certainly right in describing the corpuscles as pliant or

a Phil. Trans. 1675, x, 380. c Traite du Coeur, ed. 1749, t. ii, pp. 81,

b Phil. Trans. 1702, xxiii, 1184. 657 ; and 2d ed. t. ii, p. 277.

OF THE BLOOD. 229

If, then, they really be not globular, but flat, and if water-
so readily alters their shape, whence is it that the serum has
the property of preserving them in that form, which seems so
necessary ? because it is so general through the animal creation.

It is principally by the salts of the serum that this effect is
produced, as is proved by adding a small quantity of any neutral
salt to water, when the water is no longer capable of dissolving
those particles, nor does it alter their shape when the salt is
used in a certain proportion.

EXPERIMENT III.

If a saturated solution of any of the common neutral salts
be mixed with fresh blood, and the globules (as they have been
called, but which, for the future, I shall call flat vesicles) be
then examined* in a microscope, the salt will be found to have
contracted or shrivelled the vesicles, so that they appear quite
solid, the vesicular substance being closely applied all round
the central piece. In proportion as the solution of salt is diluted
with water, it has less effect, and when diluted with six, eight,
ten, or twelve times its quantity of water, it produces no change
in the figure of the vesicles, whose flat shape can then be seen,
even more distinctlv than when mixed with serum itself fcxi).

flexible, changing their form in passing a narrow channel, and re-
assuining their usual contour when they come into a larger space. In
mammalia, indeed, the corpuscles are very soft and elastic; when
passing a narrow capillary vessel, or impinging on a grosser particle,
they may be seen to become suddenly elongated, twisted, bent, or in-
dented ; deeply 'concavo-convex ; comma-shaped or spindle-shaped, a
part of the corpuscle being drawn into a thread ; and after all these
rapid changes, the corpuscles as quickly recover their original form.
The cup-shaped variety is often seen in blood on the object-plate of the
microscope. See the English edition of Gerber's 'Anatomy,' Note,
p. 79, and Appendix, pp. 11, 12; and * London and Edinburgh
Philosophical Magazine,' November, 1840, p. 329, for a figure of more
permanent forms, chiefly spear-shaped, lunated, and sigmoidal, which
the majority of the corpuscles of some mammalia, from an unknown
cause, occasionally assume.

(cxi.) When a solution of salt is added to the blood, the corpuscles
are made very distinct, for they are separated from each other, and their
adhesiveness is quite destroyed : see Notes xxm and c. They become
smaller ; some preserve their form, but the majority are less regularly
circular, being bent, indented, or cup-shaped ; many exhibit oblong,

230 RED PARTICLES

The neutral salts which, when diluted with water, have been
observed to have the effects above described, are Glauber's salt,
Epsom salt, a salt formed of the volatile alkali and the vitriolic
acid, common nitre, cubic nitre, a salt made with the volatile alkali
and the nitrous acid, as well as the salts made with the nitrous
acid and magnesia, or with the nitrous acid and chalk, and also
common salt, digestive salt of Sylvius, and a salt made with
vinegar and the fossil alkali. These experiments were sufficient
to- convince me, that this property was very general among those
salts which consist of acid and alkali, and therefore it seemed
unnecessary to prosecute this inquiry further.1 But acids and
alkalies have different effects on these vesicles from what neutral
salts have.

The fixed vegetable alkali and the volatile alkali were tried
in a pretty strong solution, and found to corrugate the vesi-
cles, and in proportion as they were diluted, their effects be-
came similar to water alone; but it is not easy to find the
point of strength where the vesicles would remain unaltered in
the solution. And here we may observe, that since these ve-
sicles are found to dissolve so readily in water, and not to be
dissolved in these solutions of alkali, it is a strong argument
against their being oily or saponaceous, as they have been
suspected (cxn).

1 These experiments were made by putting one drop of the saturated solution of
the salt into a teacup, and then adding distilled water by a few drops at a time,
and to this mixture the serum of the blood highly tinged with the red vesicles was
added.

triangular, or irregular depressions on the surface ; in the centre of others,
an appearance is presented as of a granular nucleus ; many become
mulberry-shaped. All these changes may be occasionally seen in pure
blood, as noticed in Note cii, p. 223, and in the Appendix to Gerber's
'Anatomy,' p. 9. Urine, when rather strong, produces the same
changes ; though in certain states it has so little effect on the corpuscles,
that it may be used for diluting the blood to observe their shape.

(cxn.) That the corpuscles are not oily or saponaceous globules,
requires no proof : see Note cvm. But I have always found that they
disappear, as if dissolved, when treated with liquid ammonia or potash.
Senaca remarks that the corpuscles, according to Leeuwenhoek, are
dissolved by volatile salts. The effect of water and of salts on the cor-

il Traite du Coeur, torn. ii. p. 135, ed. 1749.

OF THE BLOOD. 231

The effects of acids are very different. I have tried the
vitriolic, nitrous, muriatic, distilled vinegar, and the acid of
phosphorus ; these, when much diluted, have the same effect
as water in making the vesicle spherical, and in proportion as
they are less diluted, they dissolve the vesicles, without making
them spherical as water does. I never could find any point
of dilution where the acids, like the neutral salts, produced
no change on the figure of the vesicles. This experiment is ,
the more to be attended to, as these vesicles have been supposed
to be oily and saponaceous, which is improbable, since they
dissolve *more readily in acids than in alkalies.

Salts made with earth of alum, and any of the acids, always
corrugate those vesicles unless they be much diluted, when
their effects are similar to water alone ; that is, they make
the vesicle assume a spherical shape. I could not discover
any point of strength in these solutions, where the particles
would remain in them without being changed in their shape.

The same was observed of spirits of wine ; some of the me-
talline salts, as copperas, sublimate and Roman vitriol, were
tried, and when much diluted their effects were not different
from those of water ; but in proportion as the solution was
stronger, they corrugated the vesicles more and more.

Urine, when containing much of its salts, has effects similar
to the serum, but in proportion as it is weaker, its effects are
more like those of water.

The use therefore of those salts which enter into the com-
position of the blood is probably to preserve the red vesicles
in their flat form (cxin), for we must suppose some advantages
attend that shape, since nature has made use of it so generally

puscles is mentioned in Notes xciv and cxi ; and the different action of
alkalies and neutral salts on the red blood-corpuscles and pale primary
cells, in Note cxxn, p. 254. The modem names of some of the salts
mentioned in the preceding page of the text, are given in the Note
at page 12. Mr. Ancella has given a copious table of the effects of
various substances on the red corpuscles.

(cxin.) The effect of the salt of the serum is doubtless, as Hewsoii
discovered, to preserve the flat shape of the blood-corpuscles. The
salt also tends to keep them asunder, preventing that increased aggre-
gation of them which takes place in buffy blood ; and this may be a
cause of the well-known efficacy of salts in inflammation : see Note xxm.

a Lectures on the Blood, Lancet, 1839-40, i, 522.

232 RED PARTICLES

in the blood of different animals. And as both a very strong
solution of neutral salts and a very diluted one alters the
shape of the vesicles, it is probable nature has limited the
proportions of the water and the salts in our blood.

A degree of latitude in these proportions, however, seems
to be admitted, for I observed the vesicles equally unchanged
when mixed with a solution of salts, consisting of eight drops
of water to one of the saturated solution. And when added
to a mixture of fifteen drops of water to one of the same solu-
tion, not only the neutral salts in the blood are capable of
preventing the serum from dissolving the vesicles, 'but the
mucilage (cxiv), or lymph, with which the serum- is so much
impregnated, seems to contribute to the same effect.

When the vesicles have been made spherical by being mixed
with water, if a small quantity of a pretty strong solution of a
neutral salt be added, they are immediately shrivelled; a few
of them recover their former flat shape, but the greatest part
are contracted irregularly into small spheres. When these
vesicles thus recover their shape, after having been a short
time mixed with water, they are generally more transparent,
and appear thinner, a part of their substance having been dis-
solved in water, and thence it is more easy to distinguish
the little solid particle which is contained in them. By this
experiment I have had the pleasure of convincing many curious
persons of the composition of this part of the blood, who were
not quite satisfied from some of the other experiments.

I have mentioned above, and shown in Plate V, that these
vtoicles are of different sizes in. different animals. I have like-
wise observed, that they are not all of the same size in the

(cxiv.) Coagulable lymph was by many of the older writers called
mucilage — the mucago of Harveya, and in that sense the word may
have been familiar in Hewson's time. In the First Part of these
Experimental Inquiries, pp. 78, 79, and 80, he employs the term muci-
lage for the coagulable matter of the serum. Synovia was said to be an
example of animal mucilage.5 Verducc states that the coagulation of
the blood is owing to a mucilage mixed with the red part.

a De Generatione Animalium, pp. 160-1, de Physiologic, torn, ii, p. 565, and

Exer. 51, 4to, Lond. 1651. torn, i, p. 724, 8vo, Paris, 1766.

b Dictionnaire Raisonne d'Anatomie et c Traite de TUsage des Parties, 12mo,

Paris, 1696, t. i, pp. 184-5. '

OF THE BLOOD. 233

same animal, some being a little larger than others, and some
dissolve in water more readily than others (cxv) .

In the same species of animals, they even differ in size in
the different periods of life. In a chicken, on the sixth day
of incubation, I found them larger than in a full-grown hen, as
it is represented in Plate V, fig. 4, and I have found them larger
in the blood of a very young viper than in that of its mother,
out of whose belly it was taken (cxvi) . I have not, however,
been convinced from experiments that there is any difference
in size between those of a child at its birth and those of an
adult person.

In the blood of some insects the vesicles are not red, but
white, as may easily be observed in a lobster (which Linnseus
calls an insect), one of whose legs being cut off, a quantity of
a clear sanies flows from it ; this after being some time exposed
to the air jellies, but less firmly than the blood of more perfect
animals. .When it is jellied it is found to have several white
filaments ; these are principally the vesicles concreted, as I
am persuaded from the following experiment.

EXPERIMENT IV.

If one of the legs of a lobster be cut off, and a little of the
blood be catched upon a flat glass, and instantly applied to
the microscope, it is seen to contain flat vesicles, that are cir-

(cxv.) Hewson here justly notices the difference in corpuscles of the
same blood. They are not all affected in the same manner by acetic
acid ; neither are they all exactly alike in form ; nor as to the presence
or absence of the nucleus. If considered as floating glandular cells,3
they must be constantly changing from the time when they are first
formed to that when they finally melt in the plasma.

(cxvi.) Hewson has also correctly depicted the round form of the
corpuscles of the embryo of oviparous vertebrata, Plate V, figs. 4 and 7.
In the very young embryo of mammals, the corpuscles are much larger
than in the adult. At a later period, when the nucleusb has generally
disappeared, the corpuscles of the fcetus are still larger and more un-
equal in size than those of the mother ; and from the last fact it is
difficult to ascertain, at a yet later term of mtra-uterine life, whether
they he larger or smaller in the fcetus than in the adult. In a kid,
twelve days old, bred between an ibex and a goat, I found the corpuscles
larger and more variously sized than those of either of its parents. See
the Tables of Measurements at the end of this chapter, Note cxvin*.

a See Note cxvin, p. 235. b See Notes en and cxxxvu.

234 RED PARTICLES

cular, like those of the common fish (cxvn), and have each of
them a lesser particle in their centre, as those of other animals.
But there is a curious change produced in their shape by being
exposed to the air, for soon after they are received on the glass
they are corrugated, or from a flat shape are changed into
irregular spheres, as is represented in Plate V, fig. 12. This
change takes place so rapidly, that it requires great expedition
to apply them to the microscope soon enough to observe it.

I have observed the sanies or blood of a shrimp, by cutting
off its tail, and found vesicles in it similar to those of the lobster,
which have been a short time exposed to the air. But I never
could apply the blood so as to see them in their flat form ;
but since they change by exposition to the air, I conjecture that
like the lobster's they are flat in the blood-vessels, but being
more susceptible of changes from the contact of air, they were
corrugated before I could get them applied to the microscope.

The ingenious Leeuwenhoek has observed, that in the blood
of a grasshopper, its vesicles or globules, as he calls them, are
green ; I have seen the same circumstance in the white cater-
pillar, whose serum appeared green when in its vessels, but
when let out from this animal, or from a grasshopper, the
colour cannot be distinguished.

The smallest animal in which I have discerned these vesicles
is an insect no bigger than a pin's head, that is seen almost
constantly in the river water which we have in London. This
insect, which is a species of the monoculus, being put into a

(cxvu.) On the blood-corpuscles of fishes, see the observations of
Professor Wagner.a The majority of the corpuscles in osseous fishes
are of a rounded oval ; in some species, considering the breadth of the
corpuscle as 1, the length would be from 1| to If: the nuclei are,
commonly, nearly round, and the envelopes very delicate and evanescent,
as stated in Note cm. Sometimes, as in the pike, the corpuscles are
rather angular or pointed at the ends. In the cyclostomes the corpuscles
are of the same figure as those of man, and only slightly larger ; while
in the sharks and skates the corpuscles are much larger, oval, and re-
sembling those of the frog. In Mr. Yarrell's lancelet (amphioxus),
mentioned in Note CXXXTII, the blood is said to be colourless, and its
corpuscles like those of lymph.

The corpuscles of mammals, birds, and reptiles, are described in
Note XCVITI, and measurements of the whole are given in the Tables
at the end of this chapter, Note cxvm*, pp. 237 et seq.

a Physiology, tr. by Dr. Willis, i, 238.

OF THE BLOOD. 235

concave glass with a little water, and the rays of the sun being
made to pass through it, the heart may be seen to beat, and
the transparent blood or sanies found to have a few vesicles,
which appear to move one after the other ; being made visible,
though transparent, by the light passing in such a manner as
to be refracted by them.

Since so small an animal as this has these curious vesicles
equally as the larger and more perfect animals, is is not pro-
bable that they are diffused through the whole animal creation?
And what is found so generally amongst animals must be of
great use in their economy (cxvin).

As these curious vesicles therefore are so universally found

(cxviu.) The use of the corpuscles is now generally included in that
of primary isolated cells. In Note cxxn, p. 254, I have shown how the
red corpuscles differ in chemical properties from perfect and immature
pale cells. Dr. Barry a concludes that the tissues generally are formed
out of the blood-corpuscles, I think without sufficient proof. They
have been regarded as the carriers of oxygen ; and if, as Dr. Simonb
observes, the greater part of the carbon 'exhaled from the lungs in the
form of carbonic acid arises from the red corpuscles, the production of
animal heat may be connected with, this consumption by them of
oxygen. Henle,c Wagner/ Mr. Wharton Jones,6 and Mr. Newport,
consider the red corpuscles as floating glandular cells, their especial
office being, according to Mr. Jones, to convert albumen into fibrin : see
Notes i and xvm. Mr. Newport's views are mentioned in Note xci. Dr.
Simon's observationsf support Mr. Jones's conclusion. Dr. Carpenter5
objects to it, and believes that the pale corpuscles elaborate the fibrin.
Certain it is, that fibrin is formed without the immediate agency of the
red corpuscles, and in connexion with a great number of colourless
ones, in the lymphatic and lacteal vessels of Mammalia and in the blood
of Invertebrata. But to both the opinions of Mr. Jones and Dr. Carpenter
a simple and heavy objection is the fact, mentioned in Note xvui,
that fibrin and its fibrils may be produced, merely by mixing together
certain varieties of serum, in which, before mixing, no fibrinous par-
ticles can be discerned with the aid of the microscope. As to the
opinion that fibrin is formed of the central part of the red corpuscles,
Dr. Copland11 adopts the hypothesis of Sir Everard Home, with the re-
finement that the supposed separation of the envelope proceeds from the

a Phil. Trans. 1840, p. 601 ; and 1841, f Animal Chemistry, tr. for the Sydenham

p. 217. Society, i, 157, 219.

b Animal Chemistry, tr. by Dr. Day, for s Brit, and For. Med. Rev. xv, 272-73;

the Sydenham Society, i, 220. and xviii, 569.

c Anatomie Generale, tr. par Jourdan, h App. to tr. of Richerand's Physiology,

torn, i, p. 493. p. 638, 4th ed. 8vo, Lond. 1824;

d Physiol. tr. by Dr. Willis, pp. 448-49. and Dictionary of Practical Medicine,

p Brit, and For. Med. Rev. xiv, 597 ; and i, 167, 8vo, Lond. 1844.

xviii, 260-1, 263.

236 RED PARTICLES

amongst all animals, and as their structure is in all animals
similar, we are naturally led to conclude that parts so com-
plicated cannot be made by a mere mechanical agitation of
the chyle in the blood-vessels or lungs, but that nature has
set apart certain organs in the body for their formation ; and
which we shall next inquire into.

loss of its vitality on leaving the blood-vessels. Dr. Simon's hypothesis/
that such substances as urea, uric acid, and bilin, may be products of
active changes in the blood-corpuscles, has not been verified.

(cxvui*.) TABLES of the Sizes of the Corpuscles of Blood, Lymph,

Chyle, and Pus, in Vertebrate Animals.

All the following measurements were made by myself. They are
compiled from papers published elsewhere,5 containing more details as
to the names of the animals, the various sizes of the corpuscles, and
other particulars, than can be given here. Such additions and cor-
rections as further examinations have enabled me to make are now
introduced. The corpuscles of adult animals only are measured, unless
when mention is made to the contrary. The average diameter of
the corpuscles of each species is exclusively given ; in the blood of any
one of them, there are red corpuscles about a third smaller and a third
larger than the mean size ; and .among the pale globules of the blood,
chyle, lymph, and fluid of the thymus, still wider variations sometimes
occur. If the red corpuscles be obtained with difficulty from a minute
prick, they may be smaller, and more irregular in shape, than in blood
flowing freely from a larger wound. When the red corpuscles of
mammals are rapidly spread very thin and instantly dried on glass, they

a Animal Chemistry, tr. for the Syd. Society, i, 160, 163, 219, 8vo, Lond. 1845.

b On the Blood-Corpuscles of Marsupiata, of the Camelidce, and ofMoschusJavanicus,
Annals Natural Hist. Dec. 1839, Phil. Mag. same date, and Dublin Med. Press, Nov. 27,
1839; on the Blood-Corpuscles of Mammalia, Lond. .and Edin. Phil. Mag. for Jan.
Feb. March, and Aug. 1840 ; on the Blood-Corpuscles of Mammalia and Aves, in an
Appendix to the English version of Gerber's Anatomy, 8vo, Lond. 1842 ; on the
Nuclei of the Blood-Corpuscles of Vertebrata, Note to Dr. Willis's tr. of Wagner's
Physiology, pp. 240 et seq. 8vo, Lond. 1844, and Lond. and Edin. Phil. Mag. Aug.
1842 ; on the Pus-like Globules of the Blood, Phil. Mag. Sept. 1842, Note to
Wagner's Physiology (on the pale corpuscles of blood, lymph, and pus), pp. 250-52, and
Lond. Med. Gazette, Nov. 1, 1839; on the Blood-Corpuscles of the Camelida> and of
the MuskDeer, Med. Chir. Trans, vol. xxiii, and Lancet, vol. ii, 1840-41 , p. 101 ; on the
Blood-Corpuscles of the Snowy Owl and Passenger Pigeon, Proc. Zool. Soc. June 9,
1840; Corpuscles of Crocodilida, ibid. Nov. 10, 1840; Corpuscles of Paradoxures,
ibid.Nov. 24,1840; Corpuscles of Fme, ibid. May 25, 1841 ; Corpuscles of Marsupials,
ibid. June 8, 1841 ; Corpuscles of the Ibex and of Ophidian Reptiles, ibid. Aug. 9,
1842 ; Corpuscles of Strut hionidee, ibid. Oct. 11, 1842 ; Additional Measurements of
Blood-Corpuscles, ibid. Dec. 13, 1842, Feb. 13, and Sept. 10, 1844 ; Corpuscles of
the Stanley Musk Deer, ibid. May 9, 1843; Corpuscles of the Sloth, ibid. June 11,
1844 ; on the Lymph-Globules of Birds, Phil. Mag. June 1842 ; on the Structure of
Fibrinous Exudations, ibid. Oct. 1842 ; on the Lymph-Globules of Birds and Mam-
malia, Note to Wagner's Physiology, pp. 251-2 ; on the Size of the Blood-Corpuscles
of Vertebrata, Proc. Zool. Soc. Oct. 14, 1845 ; on the Size of the Blood-Corpuscles of
Birds, ibid. March 24, 1846.

OF THE BLOOD.

237

are commonly slightly larger than when they are slowly dried, or than
when they have been swimming for a few minutes either in the liquor
sanguinis, in the serum, or in dilute watery solutions of neutral salts.
On the contrary, the red corpuscles of birds and reptiles are usually
rather smaller in the dried state, however quickly it may have been done,
than in the fluid blood. The chyle-corpuscles were obtained from the
thoracic duct while digestion was active; and the lymph-corpuscles
from the lymphatic glands, except when stated to the contrary.

The measurements are all made in vulgar fractions of an English
inch ; but, for the sake of convenience, the numerator, being in-
variably 1, is omitted throughout, and the denominators only are
printed. The corpuscles were all measured as they appeared flat on
the object-plate, unless when a T indicates a measurement of their
thickness. By L. D. their long diameter, and by S. D. their short
diameter is denoted.

Remarks on the shape or size of the blood-corpuscles are contained
in Notes xcv, xcvin, cv, cxvi, cxvn ; and on the corpuscles of chyle
and lymph, in Note cxxn.

Measurements of the Red Corpuscles of the Blood.
MAMMALIA.

Homo

3200 j

3467

T . .

12400

capucinus

3454

SIMILE CATARRHINI.

Callithrix sciureus
Jacchus vulgaris . . .

3713
3624

3412

Midas Rosalia

3510

3383

Hylobates Hoolock .....

3368
3425

LEMURID.E.
Lemur albifrons •

3976

Rafflesii

3539

Catta

3892

Semnopithecus Mona ....

3515

4003

Cercopithecus Maurus ....

3468

4440

sabccus .

3342

Loris tardigradus • .

3691

T. .

12000

3461

3530

ruber . . .-
pileatus .... .

3395
3578

CHEIROPTERA.
Vespertilio murinus . .

4175

3401

4404

3478

4324

griseo-viridis ....

3429

Plecotus auritus

4465

3454

3563

INSECTIVORA.

Rhesus

3429

4747

3583

Erinaceus Europaeus . •

4085

cynomolgus . ...

3429

Sorex tetragonurus

4571

3430

3493

PLANTIGRADA.

sylvanus

3338

3940

3389

3609

Cvnocephalus Anubis ...

3461

Ursus maritimus .

3870

leucophcEtis

3555

3723

3693

SIMI.S PLATYRRHINI.

Americanus, var.

3782

Ateles subpentadactylus . . •

3620

3530

ater

3602

labiatus .

3728

Belzebuth

3589

Helarctos Malavanus

QFiftO

238

RED PARTICLES

MAMMALIA— (continued).

3824

Sus Babyroussa . .

4316

3950

Dicotyles torquatus . .

4490

Nasua fuses •

3789

4000

3878

Eleplias Indicus . . .

2745

Basaris as tut a ......

4033

Rhinoceros Indicus

3765

Ccrcolcptes caudivolvulus

4573

Bonus Caballus

4600

CABNIVORA.

T. .

13422
4000

Paradoxurus leucomystax . .

4236

Burchellii ...

4360

Bondar

5693

Hemionus ...

4421

binotatus
Pallasii . "

4660
5485

Canis familiaris

3542
3395

RUMINANTIA.

{'LD

3254

Vulpes

4117

Cainclus Dromedarius

S.D

5921

3920

T.

15337

3888

TLD

3123

cinereo-argenteus . . . .
lacopus

3761

3888

Bactrianus . . .

.\ S.D

IT.

5876
15210

3860

fL.D

3555

T. . .

14000
3645

Auchenia Vicugna . .

•Is.D

fL.D.

6444
3361

Lycaon tricolor • • . * •

3600
3801

Glama ....

'\ S.D.

6294
ibid.

3735

Moschus Javanicus

2325

3820

Stanleyanus .

0825

4662

Cervus Wapiti ....

4138

4790

Hippelaphus . .

3777

4466

5088

4274

Dania . .

4515

5365

Alces

3938

Ppljo TjftO

4322

4800

4465

Elaphus ....

4324

4481

inacrourus ' . . .

5074

Tigris

4206

5175

4319

Marhal . . .

4978

lubata • •

4220

porcinus ....

5391

4616

6330

4404

Capreolus . .

5184

T . .

6000

Virginianus ...

5036

Benjralensis . . . «

4419

Camelopardalis GirafFa .

4571

4684

Antilope Cervicapra .

5108

4220

Dorcas . . « .

4922

Serval ....

4129

T. .

6000

4175

Gnu . ...

4800

TVfii^fpla Zorilla

4270

Sing-Sing . ." .

5150

FuTO • • •

4134

5116

4205

4875

4167

5600

3502

7045

3281

6366

6430

CETACEA.

5045

3829

5300

30QQ

Tragelaphus . .

6355

Bos Taurus

4267

PACHYDERMATA.

4230

Taurus, var. . .
Bison ....

• • .

4571
4062

OF THE BLOOD.

(MAMMALIA— continued).

239

Bos Bubalus

4586

Cavia Cobaya

3538

T. . .

14000

Dasyprocta aurata . .

3857

Caffre

4703

Acouchi

3777

frontalis . .

4299

3481

4222

Hydrochaerus Capybara

3190

Lepus cuniculus . .

3607

RODENTIA.

3560

Pteromys nitidus •
volucella . •

3777
3892

Sciurus vulgaris •

4000

Bradypus didactvlus

2865

niger?

3841

maximus

3633

3457

cinereus ...

4000

3315

capistratus

3930

Palniaruiu

3847

MARSUPIATA.

Listeri

3948

Didelphis Virginiana . . . .

3557

Arctomys ? pruinosus . . . .
Empetra

3484
3503

T. . .

Dasyurus viverrinus

12000
4056

A\ 79

Maugei

4034

OQQO

3534

3911

T. . .

10910

Rattus

3754

Perameles Lagotis

3902

musculus ....

3814

Hypsiprymnus setosus . . . .

4000

38^9

Macropus Bennettii ......

3535

49fi8

ocydromus

3442

qonO

Derbyanus? . . . . .

3405

Arvicola amphibia

3790

T. . .

10910

4199

Halmaturus Billardieri . . . .

3623

Phalanfri'sta vulpina

QAl 7

Ondatra Zibethica

3550

qqcq

3856

fuliginosa

3688

Erithizon dorsatum ...

3380

3661

Synetheris prehensilis
Capromys Fournieri ...
Myopotamus Coypus . .
T.
Castor Fiber

3444
3483
3355
10667
3325

Phascolomys Wombat . . . .

MONOTREMATA.

Echidna Histrix

3456
3300

AVES.

RAPACES.

L.D.

S.D.

L.D.

S.D.

Gypaetus barbatus . .
Cathartes Iota

1913

1880

3425
3691

Aquila fucosa . . . .

1852
1830

3485
3691

Sarcorhamphus Gryphus .
Papa ....

1761
1825

3892
3600

Helotarsus typicus , .
Haliaetus albicilla . . .

1891
1829

3461
3390

Vultur auricularis . . .
Nuclei

1835
4000

3461
10666

leucocephalus . .
Aoruia .

1909
1806

3390
3585

fulvus . .

1829

3399

Falco Peregrinus

1916

3862

T. 9600
Kolbii

1794

3337

Tinnunculus . . .
subbuteo .

1891
1827

3490
3507

leuconotus . .
Angolensis . .
Polyborus vulgaris
Buteo vulgaris . . .
Lagopus . . .
Aquila chrysaetos . .
Bonelli . . .

1806
1684
1829
1852
1852
1812
1866

3425
3166
3572
3691
3691
3832
3598

rufipes . . . .
Milvns vulgaris . . . .
Gypogeranus serpentarius
Suraia Nyctea ....
Nuclei . .
Otus brachyotus . . .
vulgaris . . . .

2000
1931
1722
1555
3200
1763
1830

3790
3677
3301
4042
10666
4076
3400

240

RED PARTICLES

AVES— (continued}.

L.D.

S.D.

L.D.

S.D.

GRANIVOR^E.

Bubo maximus . . .

1720

3566

Dolichonyx oryzivorus

2400

4167

Virginianus . .

1837

4000

Ploceus textor . . . .

2213

4575

Syrnium Aluco .

1930

3801

Cardinalis Dominieana

2140

3643

Strix flammea . . .

1882

3740

cucullata . . .

ibid.

ibid.

Nuclei .

4000

10666

Amadina fasciata . .

2001

4364

passerina . . .

1885

3555

punctularia . .

2133

4133

OMNIVOR^E.

Pyrgita domestica . . .
Nuclei . .

2140
4364

3500
9200

Cracticus hypoleucus .

2116

4000

simplex . . . .

2273

4000

Barita Tibicen . . . .

2118

3892

Fringilla Calebs . . .

2253

4133

Garrulus pileatus . . .

2041

4167

Chloris . . . .

2232

3600

glandarius . . .

2064

3878

amandava ....

2243

4800

Nuclei . .

4000

10666

• cyanea

2144

3741

cristatus . . . .

2041

3512

Linaria minor ....

2416

4848

Nucifraga Caryqcatactes .

1875

4172

Parus caeruleus ....

2313

4128

Corvus corax . . . .

1961

4000

caudatus . . . .

2136

4570

frugilegus . . .

1894

3196

Nuclei . .

4800

10666

Nuclei . .

4572

9140

major

2133

3892

monedula . . . .

2243

4167

Alauda arvensis ....

2125

4128

Nuclei . .

4000

10665

Nuclei . .

4000

12000

Pica

1953

3365

Emberiza citrinella . .

2286

4000

T. . 11600

. Nuclei . .

4000

12000

.Nuclei . .

4245

11138

cristata ....

2310

4167

Gracula religiosa . . .

2075

4167

Plectrophanes nivalis . .

2133

4740

Fregilus graculus . . .

2106

4505

Loxia coccothraustes . .

2042

3790

Pastor roseus ....

2106

4630

T. . 9141

cristatellus . . .

2133

4050

Nuclei . .

4570

10666

tristis . .

1993

4167

curvirostra

2365

4000

Sturnus vulgaris . . .

2115

3892

enucleator . . .

2247

4083

Nuclei . .

3764

11333

Javensis ....

2286

3677

Drcdfttorlus

2133

4175

Astrild

2273

4740

Coracias garrula . . .

2000

3478

caerulea ....

2290

3740

Molothrus sericeus . .

2133

4567

Malacca ....

2359

4167

Buceros Rhinoceros ? . .

1690

3230

Vidua paradisaea . . .

1998

3740

Nuclei . .

3555

10666

INSECTIVOR.E.

Troglodytes Europaeus .

2359

4133

ZYGODACTYLI.

Regulus cristatus . . .

2284

4133

Corythaix Buffonii . . .

1902

3764

Motacilla alba ....

2182

3600

Cuculus canorus . . .

2028

3600

Nuclei . .

4000

10666

Plyctolophus Eos . . .

1981

3728

Sylvia Phragmites . . .

2003

3550

sulphureus

2203

3399

Philomela luscinia . . .

1895

4400

rosaceus ....

1842

3547

Nuclei . .

4000

12000

Nuclei . .

4000

12000

Curruca atricapilla . . .

2359

4133

galeritus ....

1880

3600

Erythaca rubecula . . .
Accentor modularis . .

2305
2342

4133
4000

Philippinorum . .
Macrocercus Aracanga .

1974
1902

4041
4041

rp , -i * •

2247

4000

Illigeri . .

1924

4335

i urdus Yiscrvorus • • •
musicus ....

2203

4133

Ararauna ....

1961

4128

migratorius . . .

2348

4133

Macao .

1902

4762

canorus ....

2305

3892

severus ....

2165

3801

Merula vulgaris . . .

2097

4256

Platycercus Pennantii . .

2106

3931

Orpheus polyglottis . .

2223

3732

Pacificus ....

2118

4174

rufus

2231

3646

eximius ....

2193

3892

Muscicapa grisola . . .

2179

4173

flaviventris

2118

3892

T * rr* "K'-frvr

1989

5325

Vasa ....

2045

3892

jjjvuius cxcuuitor . * •
Vanga destructor . . .

2019

3892

scapulatus . . .

2000

4042

OF THE BLOOD.

241

AVES— (continued).

L.D.

S.D.

L.D.

S.D.

Plactycercus niger . .

2133

3892

Columba cbalcoptera .

2208

4062

Nymphicus Novae-Hoi- "1
landise .

2160

4174

Nicobarica . ,
Guinea

2133
2165

3692
3839

Psittacara leptorhyncha

2067

3931

Corensis . . .

2193

3643

murina . , .

2133

4031

aurita ....

2322

3519

Patachonica . .

2115

3977

montana . . .

2239

3692

viridissima . . .

2029

4190

Nuclei .

5333

12000

solstitialis . .

2133

4000

Zenaida . . .

2203

3571

virescens ...

2097

4175

migratoria . .

1909

4626

Trichoglossus capistratus

2203

3892

coronata . . .

1954

3491

Palaeornis Alexandri .

2115

3892

leucocephala . . .

2132

3646

torquatus . . .

2174

3892

mysticea . . . •

2100

3512

Bengalensis . .

2278

4000

Lorius domicellus . .

2093

4133

GALLINJE.

Ceramensis . .

2115

4000

Penelope leucolophos . .

1902

3607

Amboinensis . . .

2045

4133

Nuclei . .

3555

9166

coccineus . . . .

2165

4000

cristata . . . .

1902

3607

Sinensis . . . .

2115

3692

Crax globicera . . .

1985

3425

Tanygnathus macro- "1
rhynchus . . . . J

2106

3829

rubra ....
Yarrellii . . . .

1993
2000

3664
3456

Psittacus erythacus . .

1898

4000

Ourax Mitu . . . .

2005

3490

albifrons . . . .

1931

3692

Pavo cristatus . . .

1835

3589

Augustus .

2085

3600

muticus ....

ibid.

ibid.

Americanus .

2115

3600

Javanicus ....

1884

3491

Regulus . . . .

2037

3764

Phasianus pictus . .

2213

3615

Dufresnii . . . .

2278

3374

nycthemerus . .

1887

3470

Amazonicus . . .

1800

3832

Nuclei . .

4000

8000

leucocephalus

2050

3727

superbus ." . .

2128

3587

badiceps . . , .

2165

3617

lineatus ....

1855

3348

menstruus

2115

3708

Nuclei .

4570

9166

melanocephalus . .

2005

3892

Colchicus ....

2168.

3646

mitratus . . . .

2029

3892

Nuclei .

5647

7111

Psittacula cana ....

2101

4174

Callus domesticus . . '

2102

3466

pullaria . . . .

2097

4174 ;

Nuclei .

6000

9140

Picus minor

2170

3892

Meleagris gallopavo

2045

3598

Numida Rendallii . .

2054

4415

ANISODACTYLI.

?rancolinus vulgaris .

2106

4041

Sitta Europaea ....

2213

4188

3erdix longirostris . . . "

2054

3801

Nuclei . .

4572

1000

Bonhami ...

1933

3282

Certhia familiaris . . .

2305

4000

Nuclei

4570

0666

Coturnix Argoondah .

2347

3470

ALCYONES.

Ortyx Virginianus . .

2213

4000

Dacelo gigantea . . .

2110

3555

neoxyenus *. .

2305

3836

Alcedo Ispida ....

2124

3693

?etrao urogallus . .

2248

3836

Tetrix . . . . \

2376

3728

CHELIONES.

Caucasica . . .

1923

3456

Hirundo rustica . . .

2133

4000

Nuclei .

4570

9166

urbica .....

2170

4000 i

'inamus rufescens . .

1752

3338

Cypselus Apus ....
Nuclei

1982
4000

3850 !
0666

ALECTORIDES.

)icholophus cristatus . .

1884

3364

COLUMB.E.

Columba Palumbus . .

1973

3643

CURSORES.

risoria

2133

3523

Struthio Camelus . . .

1649

3000

Turtur . . . . .

2005

3369

T. 9166

tigrina

2088

3615 i

Nuclei . .

3200

9166

rufina

2314

3429

16

242

RED PARTICLES OF THE BLOOD.

AVES — (continued}.

L.D.

S.D.

L.D.

S.D.

Casuarius Javanicus . .

1455

2800

Rallus Philippinensis . .

2097

3389

Dromaius Novae-Hoi- "1
landiae . . . . J

1690

3031

Gallinula chloropus .

2055

3839

Rhea Americana . . .

1898

3273

PlNNATIPEDES.

Podiceps minor . . . .

2001

3200

GRALLATORES.

(Edicnemus crepitans . .

2157

4000

PALMIPEDES.

Vanellus cristatus . . .

1964

3310

Plectropterus Gambensis

1866

3728

Haematopus Ostralegus .

1895

4000

Chenalopex ^Egyptiaca .

1866

3839

Nuclei . .
Psophia crepitans .

3200

1883

9000
3488

Cereopsis Novae-Hoi- 1
landiae J

1722

3692

Anthropoides Virgo . .

1884

3740

Bernicla Sandvicensis . .

1866

3839

T. 11230

Magellanica . . .

ibid.

ibid.

Stanleyanus . . .

1909

3529

Cygnus atratus . . . .

1806

3692

Balearica pavonina . .

1859

3777

Dendrocygna viduata . ,

1789

3555

T. 9597

autumnalis . . .

1916

3764

Nuclei . .

4000

9750

arborea . . . .

1931

3724

Regulorum . . .

1858

3478

Dendronessa sponsa . .

2001

4079

Ardea cinerea . . . .

1913

3491

Tadorna vulpanser . . .

1925

3839

Nycticorax . . .

1780

3555

Mareca Penelope . . .

1873

4385

mi nut a '. .

1993

3827

Querquedula crecca . .

2062

4592

Platalea leucorodia

1859

3600

1993

3839

Ciconia alba

1755

3439

circia .

2088

3839

niffra

1806

3403

Anas firalericulata

1937

3424

Argala

1728

3555

Larus ridibundus

2097

4000

Marabou .

1859

3460

canus ....

1973

3839

Ibis ruber

1948

3153

Nuclei

3555

10666

Numenius Phaeopus . ..

1846

4465

Pelecanus Onocrotalus

1777

3369

Limosa melanura . . .

1973

3764

Nuclei . .

3200

9600

Scolopax Gallinago . .

2170

3622

Phalacrocorax Carbo . .

2005

3765

REPTILIA.

L.D.

S.D.

L.D.

S.D.

Chelonia Mydas . . .

1231

1882

Lacerta viridis . . . .

1555

2743

Nuclei . .

4000

6000

Anguis fragilis . . . .

1178

2666

Testudo Graeca ....

1252

2216

Natrix torquata . . . .

1371

2157

radial a . " . .

1241

2197

T. 8341

Alligator ? ...

1324

2122

Nuclei . .

3835

6817

Crocodilus acutus . . .

1231

2286

Coluber Berus . . . .

1274

1800

T. 8000

Nuclei . .

3227

4986

Lucius? » . f .

1124

2215

Python Tigris . . . .

1440

2400

Champsa fissipes . . .

1259

2315

Nuclei . .

3555

7468

Iguana Cyclura ....

1230

2285

Nuclei . .

5333

6400

AMPHIBIA.

L.D.

S.D.

L.D.

S.D.

Rana temporaria . . .

1108

1821

Triton Bibronii ....

848

1311

T. 7112

Nuclei . .

1901

3000

Nuclei . .

3114

6297

cristatus ....

848

1311

Bufo vulgaris ....

1043

2000

Lissotriton punctatus . .

814

1246

T. 5625

Nuclei . .

1778

2667

Nuclei . .

2802

5261

Siren lacertina ....

420

760

Nuclei . .

1142

2007

RED AND PALE CORPUSCLES OF THE BLOOD. 243

PISCES.

L.D.

S.D.

L.D.

S.D.

Perca fluviatilis . . . .
T. 8000
Nuclei . .
Cernua . . . .
Nuclei . .
Cottus Gobio .

2099

7482
2461
6000
2000

2824

8830
3000
8000
2900

Cyprinus auratus . . .
T. 10666
'Nuclei . .
Erythrophthalmus .
Phoxinus . . . .
Esox Lucius . .

1777

4570
2000
2000
2000

2824

8000
3200
2900
3555

T. 8000
Cvprinus Carpio . . .
T. 8000
Nuclei . .
Tinea ....

2142

6400
2286

3429

8000
2722

Nuclei . .
Anguilla vulgaris . . .
T. 8000
Nuclei
Gymnotus electricus

5333
1745

7500
1745

8000
2842

10000
2599

T. 8830
Nuclei . .

8500

9600

Measurements of the Red Blood-Corpuscles of Foetal or
Immature Animals.

Human, still-born, at fifth month
of utero-ffcstation • •

2800

Fallow Deer, 5| inches long . .
Kid, 12 days old, bred between an

3478

3472

ibex and goat .

5918

2233

1098

Nuclei .
Fallow Deer, 4£ inches long . .

4600
3478

Tadpole, \ inch long . . j g'J'

1650

End of the Measurements of the Red Corpuscles of the Blood.

Measurements of Pale Corpuscles of the Blood.

3000

Vultur auricularis

3555

2800

Corvus Pica . .

3555

Cercopithecus Sabseus . . . .
Helarctos Malayanus . . . .

2900
3000
2700

Pyrgita domestica
Plyctolophus rosaceus ....

3800
3000
3200

3878

Gallus domesticus

3800

3100

Struthio Camelus

3329

Serval

3200

Casuarius Javanicus .....

2600

3200

Ciconia Argala

2666

3348

Anguis fragilis

2628

3347

Natrix torquata

2322

Capra Hircus • «

3232

Coluber Berus

2666

3200

Rana temporaria

2664

Bos Taurus

3000

Triton Bibronii

2000

Perameles Laorotis

3000

ibid.

244 CORPUSCLES OF THE CHYLE, LYMPH, AND PUS.

Measurements of the Corpuscles of the Chyle, of the Lymph, and of the

Thymus-Fluid.

CHYLE

Turdus musicus

5090

Man
Lynx

4600
ibid

Pyrgita domestica
Fringilla Chloris

4682
4924

Tlncr

ihirl

Emberiza Citrinilla

4572

Hnr<tP

ihirl

Columba Livia

5274

Gallus domesticus
Ardea cinerea .-

5261
5150

LYMPH.
Man, from a lymphatic vessel of the

Ditto, from a lymphatic vessel of
the neck . . . .

ibid

ibid.

Rana temporaria, from the sub-

Man from a gland in the groin .

ibid

cutaneous lymph

2725

Moschus Javanicus . . . . .
Strix flammea

4725
5227

THYMUS -FLUID

Garrulus glandarius

4414

Child

4572

Corvus frugilegus

5053

Cat

ibid.

Corvus monedula

5238

Calf

ibid

Pica

5001

Dromedary

ibid.

Sturnus vulgaris

5152

Measurements of the Globules of Pus.

Man from a boil ...

2664

From a seton in a cat's neck

Qonn

Pus globules in the human blood .
Ditto, in the blood of the horse .
From a subcutaneous abscess in the

2666
ibid.

From an abscess in a rabbit's leg .
From a seton in the neck of the
Vicugna .

3000
3200

horse

2900

Ditto, in the Paco

ibid

From a sero-purulent fluid in the
pleura of the horse . . . .

2962

CHAPTER II.

ON THE STRUCTURE OF THE LYMPHATIC GLANDS.

THESE glands, which by anatomists are called the lymphatic
glands, and vulgarly known by the name of waxen kernels,
since the discovery of the lymphatic vessels by Rudbeck and
Bartholine (anno 1651-2), have been properly considered as
appendages to the lymphatic system, and though many excel-
lent "anatomists since that period have employed themselves
with great assiduity, and made many curious experiments with
a view to complete the discovery of this important subject, yet
the lymphatic glands seem to have derived fewer advantages
from this spirit of inquiry than the other parts of the system ;
their structure and office being unknown, except as far as relates
to their gross anatomy, and even in that respect the best anato-
mists are not well agreed. Some suppose that each lymphatic
gland is composed of large cells, and others that they are
formed of convoluted lymphatic vessels (see Note cxix*), and
some, that the red veins communicate with the lymphatic vessels
in the substance of the gland. But in order to avoid perplexing
a subject of itself too intricate, we shall pass unnoticed the
various opinions advanced by different authors who have written
on this subject, and endeavour to describe the structure and
uses of these glands, from the ideas and experiments of the
ingenious author of the subsequent discoveries; and as the
anatomy of many parts is to be maturely considered, before we
can reason on the functions of any one of them (from the
mutual dependence they have on each other), we shall first
describe their structure, and afterwards inquire into their use.

SECT. 1. A lymphatic gland, in size and shape, is commonly
compared to a small acorn ; though I think it more generally
resembles the figure of a kidney-bean, being oblong, rounded
at the extremities, and a little flattened on the upper and under
sides, particularly in the unmjected state. But independent

246 STRUCTURE OF THE

of any change produced by injection, we observe great variety
in the size and figure of the lymphatic glands in different bodies,
and in different parts of the same body. In some they are
large and round, in others small and flat, and in every cluster
of these glands this difference in shape and size is observable.
Vide Plate VI.

In females they are generally smaller than in males, and are
always considerably less in proportion before the time of pu-
berty than after it (cxix).

SECT. 2 These glands are dispersed in the course of the
lymphatic vessels, in different parts of the body, and through
them the lymphatic vessels pass. Their various situations
have been already so accurately delineated by Mr. Hewson,1
that a repetition would be tedious and unnecessary.

1 Hewson on the Lymphatic System, Plates i-iv.

(cxix.) Morgagni, Ruysch, and Haller, according to Mr. Cruikshank,a
observed that the lymphatic glands are enlarged in the young animal
in proportion to the growth of the body, that they diminish after middle
life, and at last entirely vanish. Bichatb states that they are only very
remarkable in infancy, becoming less numerous in the adult, and mostly
disappearing in old age. I have generally found them proportionally
larger in children than in adults, and in the necks of young birds than
in their parents ; in old age the lymphatic glands are more or less
wasted, and deficient in juice, but they never entirely disappear, and
are larger in healthy aged people than in younger subjects wasted by
disease. I have seen the glands very distinctly in the neck and groin
of a woman aged 95, and of a man aged 87 ; and Dr. Boyd, who
undertook, at my request, to make a few observations on the subject,
has kindly furnished me with the following results, obtained by weighing
the glands of twenty human bodies, dead from various diseases, from
birth to 90 years of age : — " In adults the lymphatic glands were largest,
increasing up to 40 years of age, smaller at 46, and tough and fibrous
in the very old. The inguinal glands were larger and more numerous
in males than in females. The inguinal and femoral glands were smaller
in females aged 50 years and upwards, and emaciated by chronic
diseases, than in a female aged 90, whose body was in better condition.
In one male, still-born, weighing six pounds, the glands were larger
in proportion to the body, than in any other case ; and in a male infant
weighing ten pounds, aged eight months, and emaciated by disease, the
glands were smaller than in the still-born infant." The thymus gland,
as mentioned in Note cxxvn, increases in size for some time after
birth, but soon becomes smaller in ill-nourished young animals.

a Anatomy of the Absorbing Vessels, p. b Anatomie Descriptive, toin. iv, p. 431,
71, 4to, Loud. 1786. 8vo, Paris, 1803.

LYMPHATIC GLANDS. 247

SECT. 3. Each gland is a congeries of tubes/ consisting of
arteries, veins, lymphatic vessels, and nerves, connected by the
cellular substance, the whole forming a circumscribed apparatus
for the purpose of secretion (see Note cxix*). The cellular
substance surrounding the gland is a little condensed, and forms
what has been called, but improperly, its capsula (see Note cxix*).
For though we consider the cellular membrane to be the
common connecting medium of all the parts of the body, yet
we cannot allow of its forming a peculiar coat to any part, since
it cannot be separated from those lymphatic glands, without
destroying the texture of them.

SECT. 4. The branches from the aorta supply the lymphatic
glands with blood, in common with all other parts of the body.
In general two or three small branches enter each of these
glands at different parts, and these branches ramify to exceeding
minuteness (see Note CXTX*) throughout the whole gland, and
their corresponding veins return the blood into the adjacent
venous trunks.

SECT. 5. The nerves in their course give off extremely
small twigs to the lymphatic glands, but not modified to convey
an acute sensation ; for these glands, unless in a state of in-
flammation, are very little sensible.

SECT. 6. Besides arteries, veins, and nerves, every one of
these glands has a number of small lymphatic vessels. The glands
are nowhere to be found but in the course of the larger lym-
phatic vessels, which, in their passage from the extreme parts
of the body towards the thoracic duct, enter and pass through
the lymphatic glands in the following manner.

SECT. 7. About a quarter of an inch before a lymphatic
enters a gland, it divides into two, three, or four smaller branches,
sometimes into a greater number. These enter the gland at
the part farthest from the thoracic duct, and are then subdi-
vided into branches, as small as the ramifications of the arteries
and veins before described, and which they accompany to every
part of the gland. After being thus minutely divided, they
reunite and gradually become larger, as they approach the
Apposite side of the gland, forming three or four branches, which
are joined by other lymphatics, that arise from the cells of the
gland. All these branches unite together, about a quarter of
an inch from that part where they come out of the gland, and

248 STRUCTURE OF THE

form a common trunk, but larger by the additional lymphatic
vessels it receives from the cells of the gland. See Plate VI,
fig. 3.

SECT. 8. Sometimes only one lymphatic vessel, and some-
times three or four of them, pass through the same gland, in
the manner described above, and these either pass through
other glands in the same way, or continue their course on to
the thoracic duct. Vide Plate VI, fig. 1. Sometimes we ob-
serve a single lymphatic pass by all the glands, without entering
any one of them, and continue on to the thoracic duct. This
observation may perhaps account for the venereal, variolous,
or other poisons, 'being sometimes taken into the habit, with-
out inflaming a lymphatic gland in its passage." See page 129.

SECT. 9. In Sect. 3 we. found that each lymphatic gland
is a congeries of. vessels, and in Sect. 7 we observed that
some lymphatic vessels arose from the cells of the gland; but
here we do not mean those appearances which have been called
cellular1 (and that are in reality only little eminences, formed
by the bending of one vessel round another), but other cells
which really do exist in the substance of the gland, and are so
very small as to become visible only by the assistance of the
microscope.

If we inject2 a lymphatic gland with mercury, or inflate it
with air, an irregular appearance is produced, very much re-
sembling cells ; and if a gland prepared in this manner is
dried and cut through, at first sight it looks like a honeycomb,
but if we examine it more attentively, we shall find this cellular
appearance evidently made of convoluted vessels ; and in by far
the greater part of lymphatic glands, that we prepare, the
subdivision of the lymphatic vessels into smaller and smaller
branches, and not into cells, is apparent to the naked eye.
Vide Plate VI, figs. 3, and 4.

SECT. 10. The cellular appearance in the lymphatic gland
is, I think, probably a deception, which may happen in the
following way. The very small lymphatic vessels are very
much convoluted, and running in a serpentine direction one
over the other, a part of one vessel is covered by that part of

1 M. de Haller, Elem. Physiolog. torn, i, p. 183.

2 Vide Plate vi, fig. 3.

LYMPHATIC GLANDS. 249

another vessel which lies over it. This being general, an ir-
regular surface is produced, so that it looks like a number of
small globules or very small pins' heads (vide Plate VI, fig. 1),
similar to what we observe in the epididymis when injected
with mercury ; and that this is really the case I am convinced,
from what I have observed on the examination of other lympha-
tic glands, when the vessels have been less convoluted, and
where the vascular texture has been more evident ; for in some
we can distinctly trace the continuity of vessels through the
glands, especially in the more simple ones.

SECT. 11. Plate VI, fig. 2, exhibits a lymphatic vessel A,
forming three lymphatic glands : the first at B, is a subdivision
of the trunk A into about nine or ten branches, which are
convoluted, and form a gland. These unite again and form
the trunk at c, which ascending about three inches, divides
into about six branches running parallel to each other, and then
form a lymphatic gland at D, not larger than the trunk of the
vessel, which is the most simple I have ever seen ; the branches
are again united to form the trunk E ; this vessel next ascends
about three inches farther, and divides into two branches F and
G ; the branch G is continued on where it is joined with other
lymphatic vessels. The branch F is again divided into four
vessels, that are subdivided to form the third gland at H, evi-
dently composed of small convoluted lymphatic vessels ; these
vessels are again united and form the large lymphatic vessel
at i, which passes on to communicate with some other lymphatic
vessels not expressed in this Plate. All the objects in the
Plate are smaller than the natural size.

SECT. 12. This circumstance of the lymphatic glands
being formed of convoluted lymphatic vessels is demonstrable
not only in this preparation, but also in many of the larger
and complete glands, particularly in Plate VI, figs. 3 and 4 ;
and though we have not so clear a demonstration that every
lymphatic gland is a convolution of lymphatic vessels, or that
some glands may not have large cells, yet we have this useful
fact, that a lymphatic gland is not always or necessarily com-
posed of cells, and as we can prove that some, nay, many
glands are only convoluted lymphatic vessels, and as the cellular
structure in any is rather doubtful, it is probable that all lym-
phatic glands are formed of convoluted lymphatic vessels, and

250 STRUCTURE OF THE

that the appearance of large cells (cxix*) may be a deception,
from the circumstance I have already mentioned ; and I am the
more confirmed in my opinion that this is the case, on taking
a more general survey of this subject in the animal kingdom,
as in the turtle, where the lymphatic glands are wanting, or
at least that circumscribed form of a lymphatic gland, so ge-
neral in the more perfect animals, is not to be found in those
of the amphibious class.

SECT. 13. In the mesentery of a turtle no lymphatic glands
are observable; yet in this animal nature does her business as
well, though the apparatus is differently constructed. The
small blood-vessels in the mesentery of this animal are trans-
parent in an unprepared state, and the large vessels form a
network, making seemingly pretty considerable meshes, but if
we inject them (i. e. the veins and arteries) we find this part
exceedingly vascular, and from its transparency we can here
prove the artery terminating in the vein by continuity of canal
(a fact not easy to demonstrate in the human body) ; and if we
inject the lymphatic vessels, we find them very numerous, form-
ing the most beautiful network imaginable.

The lacteals come from the edge of the intestines upon the
mesentery ; part of them ascend, surrounding the blood-vessels,
but do not communicate with them. These send off lateral
branches to the transparent part of the mesentery, whilst others
come immediately from the intestines to it, where they divide
to exceeding minuteness, making frequent anastomoses, and
gradually becoming larger as they approach the upper angle,
where they communicate with the larger branches, and pass on
to the thoracic duct. Vide Plate VII.

SECT. 14. The arteries and veins are principally spread on

(cxix*.) Mr. Abernethya found the mesenteric glands of a whale
hollow in the centre, like a bag'. Mr. • John Goodsirb concludes that
the lymphatic glands are merely networks of lymphatic vessels, deprived
of all their tunics but the internal, the epithelium of which is highly
developed for the performance of particular functions ; and that these
peculiar lymphatics have a fine network of capillary blood-vessels to
supply matter for the continual renovation of the epithelium. He states
that the outer tunic of the extra-glandular lymphatics leaves them at
their entrance to or exit from the gland, and passes on its surface to
form its capsule.

a Philosophical Transactions, 1796, pp. 27 b Anatomical and Pathol. Observations,
et seq. pp. 45, 49, 8vo, Edin. 1845.

LYMPHATIC GLANDS. 251

the coats of the lymphatic vessels, so that we here find the
requisites to form a lymphatic gland ; for as we prove that
many of the lymphatic glands in the human body are no more
than a congeries of arteries, veins, nerves, and lymphatic vessels
convoluted, it is probable that all lymphatic glands may be
formed in the same manner ; so, perhaps, it may be the same
thing in nature, or the same purposes of the animal economy may
be equally well answered, whether the parts composing a gland
(viz. arteries, veins, nerves,- and lymphatic vessels) be circum-
scribed in a proper membrane, or spread over a larger surface.
This, perhaps, will be more fully proved by some experiments
and observations which I shall hereafter publish on the minute
structure of glands (cxx).

SECT. 15. On cutting into a fresh lymphatic gland we find
it contains a thickish, white, milky fluid. Then if we carefully
wipe or wash this fluid from any part of the cut surface, and
examine it attentively in the microscope, we observe an almost
infinite number of small cells, not such as have been before
described, or that have been supposed to exist in the lymphatic
glands, but others too small to become visible to the naked eye,
and expressed in Plate VIII, fig. 4.

SECT. 16. If the arteries and veins of a lymphatic gland
have been previously injected with a coloured fluid, and a part
of the gland be then \iewed through the microscope, we ob-
serve these cells are extremely vascular, and it is into these
cells that the white fluid found in the gland is secreted. This
fluid is absorbed by the lymphatic vessels, which we observed
(Sect. 7) arose from the cells of the gland, and is by them, in
common with the other fluids, carried into the course of the
circulation.

SECT. 17. The lymphatic vessels, therefore, which originate
from the cells of the gland, are in the lymphatic glands ana-
logous to the excretory ducts of other glands ; and we have the

(cxx.) I apprehend Mr. Falconar did not live to fulfil this promise,
although he devoted some space to the subject in the 8vo Synopsis of his
Lectures, dated from Craven street, Strand, London, Sept. 26, 1/77.
He must have died within a month afterwards ; for the sale catalogue of
" The Museum of the late Magnus Falconar, Surgeon and Professor
of Anatomy .... formed by the joint labour of these two young
anatomists," — Hewson and Falconar — is dated on the following 12th of
October. Of this catalogue there is a copy in the library at the Royal
College of Surgeons, in Lincoln's Inn Fields.

252 FLUID OF THE

same proofs that the lymphatic glands secrete this white fluid,
and that it is carried from the glands by the lymphatic vessels,
that we have of glands in other parts of the body separating
different fluids, and having excretory ducts ; for if we cut into a
lymphatic gland we find a white fluid, and if a ligature be
made on the lymphatic vessel coming from that gland we find
a fluid of the same kind contained in those lymphatic vessels
(cxxi). This is as convincing a proof of the lymphatic vessels
being excretory ducts to the lymphatic glands, and as satis-
factory as that the hepatic duct is the excretory duct of the
liver. We know the liver secretes bile because we find it in
that viscus, and we know the ductus hepaticus is its excretory
duct, because we find bile contained in it. The proofs are
similar and equally conclusive.

SECT. 18. The existence of a white, thick, mucus-like fluid
in the lymphatic glands has been long generally known to
anatomists, and is particularly remarked by M. de Haller ;l
but the properties of this fluid seem to have been entirely over-
looked and neglected.

This may perhaps have been owing to the same cause that
the shape of the particles of the blood, till lately, has been
so little known, viz. the want of diluting this liquor ; for if
we examine this fluid of the lymphatic glands in the natural
state, we find it a homogeneous mass, discovering nothing of
its composition or properties. But if we dilute it with a solu-
tion of Glauber's salts in water, or with the serum of the blood,
and view it with a lens of the ^ of an inch focus, as formerly
mentioned in the experiments on the blood, we then observe
the following appearance.

1 Succum glandulis conglobatis inesse, album, serosum lacte tenuiorem, in juniori
potissimum animali conspicuum, id quidem certura est. Eum, creinori sirailem dixit
Thomas Wharton, cinereum Malpighius, diaphanum Nuckius, album Morgagnus,
reete et ad naturam, ut puto, omnes. — Haller, torn, i, p. 184.

(cxxi.) I have never seen the fluid of the lymphatic vessels white
or opake, except in the lacteals and in the. absorbent ducts of the
thymus. The juice of the lymphatic glands ,may be slightly so, in
consequence of containing a greater proportion of corpuscles than
the fluid either of the afferent or efferent lymphatics/ and perhaps
when a ligature is placed on one of these last, its contents may become
more opake from an accumulation of globules.

a Note CXLH.

LYMPHATIC GLANDS. 253

SECT. 19. Numberless small, white, solid particles, resem-
bling in size and shape those central particles (see Notes en,
cv, and cxxn,) found in the vesicles of the blood, are to be
seen distinctly gliding down on the stage of the microscope, and
if we dilute it sufficiently, we can examine them separately, and
view them as distinctly as we can the particles of the blood.

SECT. 20. These particles found in the lymphatic glands
likewise agree remarkably in their properties with the central
particles found in the vesicles of the blood, not only as to size
and shape, but also in being insoluble in serum, or a solution
of any of the neutral salts in water, (except putrefaction takes
place,) and are, like the blood, soluble in water, and in the
same order (cxxn). These particles are by the lymphatic

(cxxn.) As to the solubility in water of the nucleus of the blood
corpuscle, Falconar speaks more decidedly than Hewson, who states a
that it is less soluble than the envelope. The truth is, that the nucleus,
like the globules of chyle and lymph, is insoluble in water. The partial
effect of water on the envelope is described in Notes xciv and en.

The globules of lymph and chyle, as well as those in the fluid of
the thymus, appear delicately granulated on the surface; they are
generally globular or lenticular, never following the wide peculiarities
in shape and size of the blood-discs of different classes of animals, nor
in birds at all approaching the long oval figure of the nucleus of the
red blood-corpuscle, described in Note cv.

In the Napu musk-deer the lymph-globules are about as large as
those of mammals with blood-discs of the ordinary size ; and in the
Camelidse, as noticed more fully in the Appendix to Gerber's * Anatomy,'
p. 99, figs. 286, 287, and in the 23d vol. of the ' Med. Chir. Trans-
actions/ pp. 25 et seq., the corpuscles of the fluid of the thymus and
of the lymphatic glands, as well as the pale globules in the blood and
pus, have all the same round shape as in mammals with circular blood-
discs ; and so have the globules of the lymphatic glands of birds, as
well as the pale globules of the blood of birds and reptiles. Figures
of all these globules are given in my Note to Dr. Willis's translation of
Wagner's 'Physiology,' pp. 250-52, and to the English edit, of Gerber's
'Anatomy/ figs. 277-87, and 292 ; and in the 'London and Edinburgh
Philosophical Magazine/ June, 1842, pp. 480-84. Measurements of the
globules will be found in the Tables at the end of chap, i, pp. 243-4.

The globules of the chyle, of the thymus-fluid, and of lymph, are
smaller and differ in structure from the pale globules of the blood. In
these last there are two, three, or four nuclei, easily seen when the
envelope is made more or less transparent or invisible by acetic, sul-
phurous, citric, or tartaric acid. But the globules of chyle, of lymph,
and of the thymus fluid, like the nucleib of the red corpuscles of the

a Chapter I, pp. 224-5. b See Notes cv, en.

254 CORPUSCLES OF THE LYMPH.

vessels taken into the course of the circulation, and mixed
with the blood, where they are for a time retained, to be again
separated from it, as we shall see afterwards in our inquiry
into the anatomy of some other parts.

blood, are only rendered more distinct and slightly smaller by any of
these acids, so that the central part presents no regular nuclei, or divided
nucleus, such as are contained in the pale globules of the blood. In short,
these last-named globules have the characters of perfect elementary cells,
while the former globules, as shown in the Note to Gerber's 'Anatomy,5
p. 83, resemble, and probably are, nuclei or immature cells.

The most recent observers, Dr. Oesterlen,a and Mr. Simon,b also con-
clude that the corpuscles of the thymus have the structure and relations
of nuclei ; and it has been noticed in the Introduction how sagaciously
Hewson always insisted that they are to be considered as central par-
ticles.

All these observations apply to the majority of the globules men-
tioned. In the blood, besides the common pale cells, there are a few
smaller corpuscles, like those of lymph ; while in the larger lymphatics
and thoracic duct there are corpuscles identical in size and structure
with the common pale globules of the blood: see Note CXLVI.

The microscopical and chemical characters of the globules of the
chyle, of the thymus, and of the lymphatic glands, are nearly, if not
exactly, the same. When quite fresh, they swell on being mingled with
pure water, as does the nucleus of the blood-corpuscle.0 When well
mixed with a strong solution of an alkali, or of a neutral salt, the glo-
bules become partially dissolved, misshapen or fainter, forming a very
ropy and tenacious compound with the fluid. This property, I believe,
belongs generally to fresh primary cells, though n6t to the red cor-
puscles of the blood. Further details concerning the chyle, lymph, and
fluid of the thymus, are given in the Appendix to Gerber's ' Anatomy/
pp. 88-100.

In reptiles, I have seen the envelopes forming around the pale glo-
bules of the blood, as described by Wagner and Nasse.d But in birds
and mammalia there are certain facts not agreeing with the opinion that
the red corpuscles are formed simply by a transformation of the globules
of lymph or chyle. In birds, it has already been noticed6 that the
lymph-globule differs remarkably in figure from the nucleus of the red
blood-corpuscle ; while there is nothing like a lymph-globule within
this blood-corpuscle of mammals. Besides, in some of the smaller
ruminants, as the musk-deer and ibex, the red corpuscles are much
smaller than the lymph-globules.

a Mr. Paget's Report, British and Foreign c See Note cv, p. 225.

Medical Review, vol. xxi, p. 566. d See the English edition of Gerber's
b A Physiological Essay on the Thymus Anatomy, fig. 294.

Gland, p. 80, 4to, Loud. 1845. e In Note cv, p. 225.

CHAPTER III.

ON THE SITUATION AND STRUCTURE OF THE THYMUS GLAND.

SECT. 21. THE term gland has been given to certain parts
of an animal body, that are by nature destined to separate
fluids of different properties from the general mass of blood,
which are to be applied to the various purposes of the animal
economy, or to be excreted, as being either useless or hurtful
to the constitution.

SECT. 22. But though the term gland is properly given only
to such parts as are known to perform this office, yet it has
also been applied to some parts whose uses are unknown ; be-
cause their structure being apparently the same with that of
glands, (properly so called,) it has thence been conjectured that
their uses might likewise be similar. Thus the thymus has
acquired the name of gland. In like manner we use the terms
thyroid glands and glandulse renales (cxxm). For when-
ever any part receives more blood than is necessary for the
immediate growth or nourishment of that part, it is concluded
a priori that this blood is to undergo some change, or that
some secretion is to be made from it ; and for these reasons
the appellation of gland has been given to the thymus, the
thyroid, and glandulse renales.

SECT. 23. The thymus is situated in the superior part of
the chest, in that space called the anterior mediastinum ; which
in the foetus-state, and for a few years after birth, is large.
The shape and size of this gland is various, differing in almost
every subject. It is triangular, adapted to the space between

(cxxm.) As to the probable use of the supra-renal glands, and the
nature of their secretion, see ' London Medical Gazette/ June 21, 1844,
p. 411. A description, with figures, of the elementary molecules so
abundantly produced in these glands, is given in the Appendix to
the English edition of Gerber's 'Anatomy,' p. 103; and a notice of the
constitution of similar molecules in Note LX, p. 88.

256 SITUATION AND STRUCTURE

the right and left lobe of the lungs. The superior part of the
gland seldom rises higher than the upper edge of the first bone
of the sternum. Sometimes one and sometimes two processes
of the same glandular structure arise from the upper part of
the thymus, and ascend on the fore-part of the neck almost as
high as the glandula thyroidea, and lie between the trachea
and carotid arteries ;T but this is a circumstance that rarely
occurs. The two sides of the gland are placed next the
lungs, and the inferior part or basis of the triangle extends
downwards, (sometimes much lower than is expressed in the
Plate,) lying on the upper and outer part of the pericardium,
to which it is attached by the reticular substance. The supe-
rior and posterior part of the thymus lies on that part of the
aorta called sinus aortse, which arises from the left ventricle of
the heart to form the curvature, the fore-part of which and the
common trunk of the right carotid and subclavian arteries it
generally embraces. The inferior posterior part is always con-
nected with the upper part of the pericardium.

SECT. 24. The thymus receives two small arteries, called
arteriae thymicse, which most commonly originate from the
sinus aortse; sometimes they arise from the curvature of the
aorta, and I have seen some instances of one small artery
coming from the common trunk of the right carotid and sub-
clavian arteries to the upper part of this gland. Besides these,
the thymus receives several small arterial branches on its fore-
part, from the mammary and other arteries, that supply the
mediastinal space with blood.

SECT. 25. The veins are always more regular in their ter-
mination, and are generally two in number. They open into
the trunk of the jugular and subclavian veins on the left side,
of which a part is covered by the superior portion of the
thymus.

SECT. 26. The thymus is a gland of the conglomerate kind,
and, like others of that class, has no particular centre of rami-
fication for its blood-vessels, but they enter promiscuously at
different parts of it. It is formed of a great number of small
lobules, or acini, united to each other by blood-vessels and the
tela cellulosa; and over the whole, giving it greater compact-
ness, is a condensed cellular substance, which forms a kind of
1 Hall. torn, i, p. 115.

OF THE THYMUS GLAND. 257

capsule to the gland, and gives it a pretty regular smooth ex-
ternal surface, except where it is fissured into larger lobes.
But this capsule is not of that kind we find on some other
glands, as on the kidneys, &c., which can be readily separated
from them. It is nothing more than a coarser condensed re-
ticular substance adhering firmly to all parts of it ; from which
it cannot be separated, without doing injury to the glandular
substance (cxxiv).

SECT. 27. Many attempts have been made, by dissection
and other means, to discover an excretory duct from this part.
For the organization being apparently the same in it as in some
other known glands, it was but natural to conclude that, similar
to them, it also should have an outlet. Accordingly, many
fruitless experiments have been made, and much time employed
to discover it, but with so little success, that all attempts of
that kind seem long since to have been given up. Nay, some
have been led into very unphilosophical conjectures, viz. that
perhaps it was useless, or that if it did perform any office, it
was so obscurely as to escape investigation.

SECT. 28. But the ingenious author, whose experiments we
are about to relate, entertained too exalted an idea of Nature
to suppose that any part of the animal frame was useless, though
the structure of some parts might be so intricate, and their
uses so obscure, as to elude the researches of the most assiduous
and ingenious inquirers into the operations of nature.

SECT. 29. Mr. Hewson, after having made many attempts
by dissection and injections to discover the use of this gland,
with almost as little success as his predecessors, began to employ
the microscope ; but microscopical experiments, in the manner
they were then conducted, afforded no other satisfaction here
than that the blood-vessels were distributed in a similar manner
to those of the lymphatic glands ; but the external appearance,
as well as the minute structure of the thymus (so exactly cor-

(cxxiv.) The structure of the thymus has been particularly described
by Sir Astley Cooper,a Dr. Haugsted,b and Mr. Simon.c The two
authors last named have given full notices of the labours of the earlier
writers on the subject.

a Anatomy of the Thymus Gland, 4to, logica, et Physiologica. 8vo, Hafniae,

Lond. 1832. 1832.

b Thymi in homine ac per Seriem Ani- f A Physiological Essay on the Thymus

malium descriptio Anatoiuica, Patho- Gland, 4to, Lond. 1845.

17

258 SITUATION AND STRUCTURE

responding with the structure of other glands), convinced Mr.
Hewson it must have an excretory duct ; yet possibly it might
be so small, or the coats so transparent, that when collapsed in
the dead body it might become almost invisible ; though during
life, while distended with the natural fluid, it might be more
readily perceived. Therefore the following experiments were
made in order to detect it.

EXPERIMENT I.

SECT. 30. The sternum of a half-grown dog being removed,
a ligature was passed round the thymus, including at the same
time all the neighbouring parts. The animal soon died. On
examining the parts contained within the ligature, no excretory
duct could be found ; but a great number of lymphatic vessels
made their appearance, filled with a darker coloured fluid than
ordinary.1

As the gland in this dog was small, it was suggested that the
experiment would probably succeed better in a larger animal,
which gave rise to the following experiments.

EXPERIMENT II.

SECT. 31. The chest of a calf being opened, a ligature was
passed round the lower part of the thymus, as had been done
in the former experiment, and the parts contained within the
ligature were taken out. On examining these very attentively,
a great number of lymphatic vessels, containing a fluid almost
similar to chyle, of a white colour, but not quite so opake, were
seen coming from every part of the gland ; one of which was
so large, that at first sight it had the appearance of an excretory
duct ; but on a more attentive examination, it was discovered
to be no other than a large lymphatic vessel. The remaining
parts were dissected with all possible care, but no excretory
duct could be seen.

1 Ubinam is succus habitet, nondum consentitur. Ex thymi tamen exemplo, maximae
glandulae, crediderim, cum Nuckio, oinnino in areolis cellularum residere. Nam in
tota thymi glandula, ubicunque laeseris, exiguo etiam vulnere, in earn violationem ex-
primi potest, neque tamen aut manifesta cavitas reperitur, qua contineatur, neque ex
vase aliquo effluere videtur, cum et copia earn guttulam superet, quae ex vase non
magno inciso speretur, neque ex remotis giandulae partibus per vascula adeo facile in
vulnus urgeri posset, et denique manifesto cum spuma ex cellulis cavernulisque ex-
primatur. — Hall. Elem. Phy. torn, i, p. 184.

OF THE THYMUS GLAND. 259

SECT. 32. The fluid found in the lymphatic vessels, coming
from the thymus, differing so much in colour (cxxv) from what
is contained in the lymphatic vessels of the other parts of the
body, was an inviting circumstance to examine the properties
of it, with intent to determine upon what cause this remarkable
difference in colour depended.

EXPERIMENT III.

SECT. 33. A drop or two of the fluid found in the lymphatic
vessels coming from the thymus gland, being received upon a
thin piece of glass, and examined in a microscope, with a lens
of — of an inch focus, it appeared opake, and like a drop of
milk. But on diluting it with a few drops of the serum of
human blood, the same appearance was exhibited as was ob-
served on examining the fluid found in the lymphatic glands,
a great number of small, white, solid particles, exactly resem-
bling in size and shape the central particles in the vesicles of
the blood, or such as are found in the fluid of the lymphatic
glands.

EXPERIMENT IV.

SECT. 34. A few drops of the same kind of fluid as in the
former experiment were diluted with a small quantity of a
solution of Glauber's salt in water (as mentioned in Experi-
ments on the Blood), and on viewing this with the microscope,
the same particles were more distinctly seen than in the pre-
ceding experiment, on account of the fluid being more di-
luted (cxxvi).

SECT. 35. Particles of this shape being found in large
quantities in the lymphatic vessels coming immediately from
the thymus, through the substance of which lymphatic vessels

(cxxv.) See page 252 and Note cxxi.

(cxxvi.) The globules of the juice of the lymphatic glands and of
the thymus have the same microscopical and chemical characters:
see Note cxxn, pp. 253-4. The experiments in the text are most impor-
tant. They should be carefully repeated with some modifications and the
improved aids that science now affords. No experimental inquiry con-
cerning the office of the thymus can be satisfactory without exact
researches as to the nature of the matter carried by those vessels which,
on such high authority, have been considered as the excretory ducts of
the gland. See Notes cxxvu and CXLIV.

260 SITUATION AND STRUCTURE

ramify to every part, gave reason for suspecting that these
lymphatic vessels were possibly the excretory ducts of the
thymus, and the following experiment proved the conjecture
to be well founded.

EXPERIMENT V.

SECT. 36. On cutting into the substance of the gland, it
was found to contain a white thick fluid,1 in most respects
resembling the fluid found in lymphatic glands, only in larger
quantity. A small portion of this fluid being received on a
thin piece of glass, was diluted first with serum, then with a
solution of Glauber's salt in water, and examined with a mi-
croscope. In both these experiments the appearances were
exactly the same, as we have related in the Experiments third
and fourth ; namely, numberless small particles precisely cor-
responding with those found in the lymphatic vessels passing
from the thymus, and with those found in the fluid of the
lymphatic glands.

EXPERIMENT VI.

SECT. 37. A small portion of the thymus gland having re-
mained in water a few minutes, in order to wash the white
fluid from its surface, was examined with the microscope, and
the cellular appearance was seen here as evidently as in the
lymphatic gland, which it in every respect resembles.

SECT. 38. From these experiments we are led to make the
following conclusions. That one use of the thymus is to
secrete from the blood a fluid, containing numberless small
solid particles, similar to those found in the lymphatic glands ;
and that the lymphatic vessels arising from the thymus convey
this secreted fluid through the thoracic duct into the blood-
vessels, and thus become the excretory ducts to this gland.
That the structure and uses of this gland are similar to those
of the lymphatic glands, to which it may be considered as an
appendage. And that this is the fact, is more probable from

1 Interiorem si rimeris fabricam, in omnibus, quos unquam vidi, fetubus reperies,
incisione facta, quocumque loco visum fuerit, ut tamen omnino caro glandulae laedatur,
succum lacteolum, frequenter etiam sanguine tinctum, ejusque non minimam copiam
exprimi posse. Pressa quacunque glandulae parte succus in vulnus confluit. Bum
succum stillatitius vini liquor in grumos cogit. — Hall. Elem. Phy. torn, iii, p. 116.

OF THE THYMUS GLAND. 261

observing, that the thymus exists during the early periods of
life only, when those particles seem to be most wanted (cxxvn).
SECT. 39. Probably the thymus is formed in the human
embryo, in the same proportion with all the other parts of the
animal. It appears distinctly about the end of the third or
beginning of the fourth month from conception. From this

(cxxvu.) In the calf, Sir Astley Coopera describes two large vessels,
which he declares to be the absorbent ducts of the thymus, running
upon its posterior surface, carrying the fluid of the gland, and ter-
minating in the jugular veins at their junction with the superior cava
by one or more orifices on each side. He dissents from the opinion
that the structure of the thymus and of the absorbent glands is similar.
" One is conglobate and the other conglomerate ; one is firm and
compact, and the other loose and pulpy; the one contains cells of
considerable magnitude when in the distended state, whilst in the ab-
sorbent glands the cavities are small, and with so much difficulty traced,
that there is still a doubt if they be cellular or vascular." The structure
of the lymphatic glands is noticed in Sect. 12 and Note cxix*. Sir
Astley concludes, like some of the old anatomists, as Glissonb and
Dionis,c that the use of the thymusd is to prepare a fluid well fitted for
the growth and nourishment of the foetus, before its birth, and con-
sequently before chyle is formed from the food. But the thymus is
not merely an organ to supply the wants of foetal life ; for, as I have
noticed in the Appendix to the English edition of Gerber's ' Anatomy,'
pp. 97-8, the functions of the gland are very active some time after
birth, at which period Dr. Haugsted6 has proved, in brutes, that the de-
velopment of the thymus, both proportional and absolute, is greatest.

According to my observations, just cited, the thymus and its juice
soon become diminished in ill-fed, over-fatigued, and diseased young
brutes, and in badly-nourished and diseased infants. On this subject
my friend Dr. Boyd, who has long been employed at the parochial
infirmary of St. Marylebone, in researches concerning the weight of the
human organs, has given me- the following note :

" The weight of the thymus, in 170 cases, was found to vary more
than any other organ, in early life. In a female foetus, 10£ inches long
and 10i ounces weight, the thymus weighed 6 grains; in a still-born
female, 22 inches long and 9 Ib. 10 oz. weight, the thymus weighed
340 grains. In 7 male still-born children, out of 24 examined, the
thymus weighed half an ounce and upwards, and its average weight
was 154 grains. In 3 female still-born children, out of 25 examined,
the thymus also weighed half an ounce and upwards, and its average
weight was 148 grains.

"The weight of the thymus was greater in males than in females;

a Anatomy of the Thymus Gland, pp. 14, c Anatomic de 1'Homme, 5th ed. p. 497,
15, 38, 44, 8vo, Lond. 1832. 8vo, Paris, 1716.

b Anatomia Hepatis, cap. xlv, p. 443, d See Note CXLIV.

8vo, Lond. 1654. e Thymi Descriptio Anatomica, cap. xi,

pp. 89 et seq., 8vo, Hafniae, 1832.

262 SITUATION AND STRUCTURE

period to the time of birth, its size is considerably increased,
when it is commonly about the size of a small walnut, though
not of that figure. In some it is much bigger, but in others
it does not exceed the size of a large filbert-nut.

SECT. 40. From the time of birth to the end of the first
year, the gland continues to grow larger, and keeps pace with
the general growth of the other parts of the body. From the
end of the first to the third year, it is neither perceptibly in-
creased nor diminished, but preserves nearly the same size it
had acquired at the end of the first year. From the third to
the eighth or tenth, it decreases in size, and, gradually wasting,
becomes less and less till the child has reached to between its
tenth and twelfth year, when ordinarily it is perfectly effaced,
leaving only a ligamentous remains, that degenerates into a
kind of reticular substance. As the gland becomes less, the
vessels that supplied it with blood for secretion diminish in
proportion, and at length when the gland totally disappears,
these, like the umbilical vessels, being no longer wanted, de-
generate into mere ligaments. Sometimes, though very rarely,
they continue pervious, (but their diameters are exceedingly
contracted,) and carry blood to the remains of the thymus and
the mediastinum.

SECT. 41. This curious circumstance of the thymus being
largest in the earlier periods of life, and becoming gradually
less as the animal advances towards maturity, constantly takes
place in the human subject, though the periods, when these

in 86 children, from birth to 2 years of age, who died from various
diseases, the average weight of the thymus was 90 grains in 44 males,
and 80 grains in 42 females. In 14 males from 2 to 6 years of age,
the thymus weighed 104 grains, and 71 grains in 21 females from 2
to 18 years of age.

" In emaciating diseases the thymus wastes rapidly, almost to a mere
membrane devoid of juice. In a female aged 13 days, weighing at
birth 6 lb., and after death but 3 Ib. 11 oz., the weight of the thymus
was only 10 grains; in another emaciated female, aged 18 days, the
thymus weighed 15 grains. Of children not emaciated, in one male
aged 7 months and in another aged 1 1 months, who both died of acute
arachnitis, the thymus in the first was 330 grains, and in the second
220 ; and in a female, aged 1 month, who died of convulsions, the
thymus weighed 330 grains."

The size of the lymphatic glands at different periods, is mentioned
in Note cxix, page 246.

OF THE THYMUS GLAND. 263

changes happen, may vary occasionally, and it is probable that
they do so in some degree in almost every individual. But I
have never seen an instance of the thymus continuing till the
time of puberty (cxxvin). These changes in the thymus are
not confined to the human body. The same generally take
place in all quadrupeds. The thymus of a calf, called by
butchers the neck sweetbread, is not found in the bullock of
eight years old; at that age it is entirely wasted, and the
same change obtains in every other quadruped that I have had
an opportunity of examining.

SECT. 42. The inference naturally drawn from these expe-
riments is, that the thymus is necessary to perform an office
requisite in the foetus-state, and in the early part of life de-
pending upon respiration.

What this office is, we shall hereafter endeavour more fully
to explain (cxxix).

(cxxvin.) It is now well known that the thymus is occasionally
found in adults, examples of which are quoted from various authors by
Mr. Simon. a I examined it from a woman aged 25, and found that it
contained only a trace of the fluid so abundant in the gland when its
functions are active. The thymus, as mentioned in Note cxxvu, is
larger after than before birth in healthy animals ; and probably also in
the human subject, though this point requires further observations on
children who have died suddenly. On the development of the thymus
Mr. Simon has given copious details.

(cxxix.) See Sections 91-94, and Notes cxxvn, CXLIV.

a Physiol. Essay on the Thymus Gland, pp. 28, 31, 32, 4to, Lond. 1845.

CHAPTER IV.

ON THE SITUATION AND STRUCTURE OF THE SPLEEN.

SECT. 43. It hath at all times been matter of surprise
among the learned, that a viscus so large, and so advantage-
ously situated as the spleen is, added to the frequent oppor-
tunities of inspecting it in different states of health, should,
notwithstanding, have its uses so involved in obscurity, as to
elude the researches of so many ingenious and industrious
inquirers.

SECT. 44. Not that the spleen has at any time been con-
sidered as useless, for at different periods a variety of different
offices have been assigned to it. Among the ancients, the
most celebrated opinion was, that it made the atra bilis or
succus melancholicus, which they supposed was carried by the
vasa brevia into the stomach ; but later observations have
entirely exploded that idea, insomuch that the very term is
almost extinct. And we shall endeavour to prove, that the
more modern opinion, of its producing some change on the
blood preparatory to the secretion of bile, hath no better
foundation in nature.

SECT. 45. But it will be unnecessary to repeat the various
opinions that have been entertained at different times respect-
ing the use of this viscus. Our present endeavour will be to
describe its situation and structure, and afterwards to inquire
into some particulars respecting its use.

SECT. 46. The spleen then forms the superior part of the
abdominal viscera on the left side ; its figure is rather oblong,
a little convex on its outer or upper, and a little concave on
its inner or lower side ; it is placed obliquely in the left hypo-
chondrium, with its convex surface exactly corresponding with
the concave or under surface of the diaphragm, to which it
sometimes adheres, but is always in contact with it, unless
when the left lobe of the liver extends very far over into the

SITUATION OF THE SPLEEN. 265

left side, and, covering the upper surface of the spleen, is inter-
posed between it and the diaphragm ; which is sometimes,
though very rarely, the case. The inner or concave side of the
spleen, from its oblique situation, is turned a little downwards,
looking at the same time towards the spine, and to this part
a portion of the omentum is attached. The edges of the spleen
are not thin like those of the liver, but thick and round, giving
a spheroidal figure to the whole.

SECT. 47. But the spleen is not uniformly of the figure above
described; sometimes we find it fissured into two or three lobes,
almost dividing it into so many distinct spleens, and frequently
we find the edge of it serrated.

SECT. 48. It is generally a solitary viscus, yet two1 distinct
spleens have been found in the same body, sometimes three,
and sometimes a cluster, as it were, of little spleens ; but these
are extraordinary deviations from the general conformation of
the body, and when found, may properly enough be considered
as so many freaks of nature.

SECT. 49. The ordinary weight of the spleen is from six to
ten ounces ; in some subjects it has been found very large, ex-
ceeding the weight of five pounds; but as this preternatural
enlargement is ever found to be the effect of disease, so from
disease in other cases, or from some cause existing in the body,
it is found considerably diminished. One instance I have also
seen of a spleen not more than one ounce in weight, yet it had
the appearance of being perfectly sound (cxxx).

1 Hall. Elem. Phy. torn, vi, p. 387. Est tamen unus tantum quamvis praeter
naturam duplex quoque nonnunquam observatus sit. — Adriani Spigelius de Human!
Corporis Fabrica, cap. xiv, p. 3t)9.

(cxxx.) Dr. Boyd finds that, in adults, the spleen is more variable
in size and weight than any of the human organs, excepting the womb
and ovaries. I am indebted to him for the following notes of his ob-
servations. The bodies died of various diseases.

"In 346 males, aged from 20 to 60 inclusive, the average weight of
the spleen was 6 '78 ounces. The largest spleen was 35 '5 ounces, the
smallest */5 of an ounce. The spleen was largest between the ages of
30 and 50, when its average weight in 182 males was 7'23 ounces.

"In 314 females, aged from 20 to 60 inclusive, the average weight
of the spleen \vas 5 '42 ounces. The largest spleen was 20 ounces, the
smallest vo of an ounce. The spleen was largest between the ages of
20 and 40, when its average weight in 123 females was 6*47 ounces."

266 SITUATION AND STRUCTURE

SECT. 50. From the spleen being in contact with the dia-
phragm, and not fixed to the sides of the abdomen, its situation
will be continually varying in the act of respiration, which will
occasion much difficulty to determine at all times the exact
situation of it.

SECT. 51. A spleen weighing nine ounces most commonly
measures about six inches long and four inches broad.

SECT. 52. In a well-formed chest, in a state of the deepest
expiration, from the cartilaginous margin of the thorax to the
highest lateral part of the diaphragm, generally measures about
six inches ; therefore, supposing this to be the standard in the
utmost expirations, the upper end of the spleen will ascend so
high up as the lower edge of the eighth rib, and in this state
the inferior part will be opposite to the lower edge of the tenth
rib, or the whole of the spleen will be contained between the
eighth and tenth ribs. In the deepest inspirations it never
descends below the cartilaginous margin of the chest, unless it
be preternaturally enlarged. Thus, by attending to the state
of respiration, we may be able to form a good judgment of the
situation and extent of this viscus ; but if we wish to deter-
mine it with greater exactness, let the arm be raised as high
as possible, and a line drawn from the inferior angle of the
scapula, parallel to the spinous processes of the vertebrae dorsi;
the whole of the spleen will be contained within the line drawn,
and be found to occupy the space between the eighth and tenth
ribs in a state of expiration ; but in a deformed chest, or the
chest of a woman whose ribs are pressed in by stays, it may
differ considerably. In a woman whose ribs had been pressed
in by stays, but not more than is ordinarily found, from the
cartilaginous margin of the eleventh rib to the centre of the
diaphragm, measured six inches and a half. The spleen
weighed nine ounces two drachms and a half, and measured
five inches and three quarters in length, three inches and
seven eighths in breadth, and one inch seven eighths in thick-
ness ; the upper edge was opposite to the upper edge of the
eighth rib, and the lower part was opposite to the upper edge
of the eleventh rib ; thus the whole spleen in this subject was
placed between the eighth and eleventh ribs. And this will in
females, I fancy, be found to be the general standard.

SECT. 53. The spleen has generally been described of a dark,

OF THE SPLEEN. 267

blueish, leaden, or livid colour, and this is the aspect it com-
monly wears when we examine it in a body a few days after
death, or when putrefaction has taken place; but if we ex-
amine it in a human body a few hours after death, or in an
animal soon after it has been killed, we find it of a deep red
or blood colour, which gradually changes as putrefaction ad-
vances. We shall therefore conclude that the colour, which
has been generally considered as characteristical of the spleen,
is no more than the effect of that change which takes place in
all animal substances after life is extinct.

SECT. 54. The spleen, in common with all other viscera con-
tained in the cavity of the abdomen, hath an external covering
from the peritoneum; under the peritoneal coat is a proper
capsule surrounding the whole gland, and to which its tender
substance closely adheres.

SECT. 55. The substance of the spleen, particularly if putre-
faction hath taken place,. is extremely soft and tender, readily
breaking down under the touch, and exhibiting that appear-
ance called by the Greeks parenchyma ; 1 and at the first sight
it hath much the appearance of effused blood; but many ex-
periments prove that this tender substance is no other than
very small vessels broken down by putrefaction (cxxxi), and
not parenchyma.

SECT. 56. On cutting into the spleen, many small ligaments
are seen passing from side to side of it, and those in quadru-
peds being large and intersecting each other, gave rise to the
opinion, that the spleen was full of large cells into which the
blood was thought to have been poured, and these cells were
supposed to be demonstrated by a spleen prepared in the fol-
lowing manner. An injection pipe being fixed into the artery
or vein of the spleen of an ox, warm water is injected, and
the substance of the spleen is kneaded (by which the small

1 Quarta denique, parenchyma in qua sanguis effusus circa venas nulla sen dispo-
sitas. — Adrian! Spigelii de Human! Corporis Fabrica, p. 108.

(cxxxi.) The effect is too rapid for the cause assigned by Mr. Falconar.
The change is probably owing to a softening of the fibrin of the blood
coagulated in the spleen after death, and not to an alteration in the
tissue of the organ. See Andral's Hematologie Pathologique, 8vo,
Paris, 1843, pp. 70-71.

268 SITUATION AND STRUCTURE

vessels are broken down) with the hand; the bloody water
being pressed out, and with it the small vessels, fresh water is
injected, and this process repeated until the water returns
colourless ; it is then inflated and dried. On cutting into a
dried spleen thus prepared, it exhibits a cellular appearance,
which has been called the cells of the spleen ; but although
these cells are artificial, and the structure of the gland is en-
tirely destroyed by that mode of preparation, yet we shall pre-
sently endeavour to prove that there are cells, but of a different
sort, existing in the substance of the spleen.

SECT. 57. The spleen is composed of arteries, veins, nerves,
and lymphatic vessels, which are distributed to every point of
it, so that it seems a mere congeries of vessels, and conse-
quently receives a very large quantity of blood, and for that
cause it has been very properly supposed to be a gland ; and
according to that idea, anatomists have made every attempt
that their invention could devise to discover its excretory duct,
but without success.

SECT. 58. The aorta, whilst in the cavity of the abdomen,
gives off from its fore-part three branches : the first of these,
called the cceliac artery, springs from the main trunk of the
aorta as soon as it enters the cavity between the two crura of
the diaphragm, and is immediately divided into three distinct
branches, the first of which is called the coronary artery of
the stomach, and carries blood to the lesser curvature of the
stomach. The second branch, which carries blood to the liver
for its nourishment, is called arteria hepatica. And the third
branch, which is that we are now about to trace, is called
arteria splenica, and carries blood to the spleen.

SECT. 59. The splenic artery, in its passage to the spleen,
runs in a furrow through the whole length of the pancreas, and
by several small branches supplies that gland with blood for
the secretion of the pancreatic juice; besides which, in its
course nearer toward the spleen, this vessel also gives off four
other arterial branches, called vasa brevia, which are distributed
to the greater curvature of the stomach, and the last of these
going near the left extremity of the greater curvature, is called
gastrica sinistra. The trunk of the artery then passes on to
the spleen, and is divided into five or six branches, which enter
the concave side at the hollow or sinuosity of the spleen, and

OF THE SPLEEN. 269

as soon as they have passed through the capsule, are divided
into exceedingly small twigs, which are distributed to every
point of the gland. The arteries, thus minutely divided, trans-
mit the redundant blood to the veins, which becoming larger
as they approach nearer to the sinuosity of the spleen, at length
pass out in branches, which everywhere accompany the arteries
that entered it ; these branches uniting form the splenic vein,
the blood of which will not coagulate by exposition to the air,
like other venous blood (cxxxn). The trunk of the vein then
attends that of the artery, receiving veins from the stomach
and pancreas, which correspond with the branches given off by
the artery ; the vein then passing on joins other veins from
the intestines, &c., which transmit their blood by the vena
portarum to the liver, for the purpose of secretion.

SECT. 60. Lymphatic vessels in great numbers may be dis-
tinctly seen running everywhere on the external surface of this
gland ; insomuch that the spleen of a calf has ordinarily been

(cxxxn.) According to Mr. Thackrah,a the blood of the vena portae
coagulates much quicker, though the clot is softer, than the blood of
other veins. Tiedemann and Gmelinb declare that the blood of the
splenic vein coagulates like the blood of other organs. Schultzc found
a much larger proportion of fatty matter in the dried constituents of
the blood of the vena portse, especially in the fibrin, than in those of
arterial and venous blood of other parts. Dr. Simon/ from an exami-
nation of the portal blood of two horses, concludes that it coagulates
more slowly, and contains more haematin and less fibrin than either
arterial or common venous blood. In horses shot on account of lameness,
in horses dead from disease, in drowned kittens, and in a dog killed by
hanging, Mr. Siddall and I found the blood in the splenic vein less per-
fectly coagulatedthan in the other veins, butgenerallysomewhatgrumous,
and containing a few soft though distinct clots. In one horse, shot in
consequence of paralysis, the blood was fluid in the splenic vein, but
there were some small red clots in the splenic artery. The blood in the
splenic vein was always dark-coloured, not of a brilliant red, as stated by
Senac ;e though it was readily brightened by neutral salts, contrary to
the experience of Schultz/ In the splenic vein of man, after death from
disease, I have frequently seen a clot ; and so has Mr. Evans.g Is not
the ordinary firmness of the spleen, some time after death, owing to
coagulated blood?

a Inquiry into the Nature, &c., of the rt Animal Chemistry, tr. for the Syd.

Blood, ed. 1834, pp. 97-101. Soc. vol. i, pp. 201-4, 8vo, Lond. 1845.

b Muller's Elements of Physiology, tr. by e Traite du Co3ur, 2d ed. torn, ii, p. 282.

Dr. Baly, vol. i, p. 572, 1st edit. f Lancet, 1834-5, vol. ii, p. 572.

c Lancet, 1834-35, vol. ii, p. 573. s Lancet, 1844, vol. i, p. 65.

270 SITUATION AND STRUCTURE

chosen on which to demonstrate the lymphatic vessels; and
they are also as numerous in the internal substance as on the
external surface, which we can prove in fish, whose lymphatic
vessels are without valves, so that we can inject them from
trunk to branch. Now if we fill the lymphatic vessels coming
from the spleen of a fish with a red injection, we can colour
the gland as highly as if it had been injected by the artery or
vein ; hence it is evident that the lymphatics are coextended
with the blood-vessels to all parts of this gland.

SECT. 61. In the human body the lymphatic vessels pass
through some lymphatic glands which are situated near the
sinuosity of the spleen, from whence they pass on towards the
thoracic duct, into which they empty themselves.

SECT. 62. The nerves inservient to the spleen are branches
from the par vagum and intercostal nerves, which form a plexus
called the splenic; these enter the sinuosity with the blood-
vessels, and attend them through their minutest ramifications.

SECT. 63. Thus we have shown that the spleen is extremely
vascular ; insomuch that when injected it appears a mere con-
geries of vessels, and that the quantity of blood circulating
through it is very considerable. „

SECT. 64. In section 56 we said, that there are cells in the
spleen, but not of the kind commonly supposed to have been
demonstrated in spleens prepared as there described ; but
although we deny the existence of such large cells, (which are
no other than what may be called the skeleton of a spleen,
made by destroying its minute structure,) yet we assert that
there are innumerable cells dispersed throughout the whole
substance of the spleen, but they are so very small as not to
be discovered without the aid of a microscope : these may be
seen in the following manner.

SECT. 65. Take a small thin piece of a spleen that has been
minutely injected, (i. e. the arteries and veins completely filled
with a coloured injection,) steep it a day in clean water, chang-
ing the water frequently; upon examination of this with a lens
•j^ of an inch focus, an almost infinite number of cells may be
distinctly seen, the round figure of which, as well as their great
regularity, sufficiently distinguishes them from the irregular
interstices of the reticular substance. The size and shape of
these cells so nearly resemble those we have before described

OF THE SPLEEN. 271

in the lymphatic glands, that a tolerably accurate idea of them
may be obtained by referring to Plate VIII, fig. 4. The ulti-
mate branches of the arteries and veins are so distributed as
to form a most beautiful network of blood-vessels upon each
particular cell, and we shall render it probable that the ex-
treme branches of the arteries form a secretion into these cells.
SECT. 66. Mr. Hewson, in the beginning of his inquiries
after the excretory duct of the spleen, was not more successful
than his predecessors had been ; but having observed that the
lymphatic vessels were the excretory ducts of the lymphatic
glands, and also that the lymphatic vessels of the thymus per-
formed the office of an excretory duct to that gland, he was
led, from this circumstance, to conjecture that the great num-
ber of lymphatic vessels found in the spleen might possibly be
intended to return the secreted fluid from it, and thereby be-
come in effect its excretory duct. In order to discover if his
conjectures were well founded, the following experiments were
made.

EXPERIMENT I.

SECT. 67. A dog was opened alive, and after a ligature had
been passed round the splenic vessels, the whole spleen was cut
out.

SECT. 68. On examination of the lymphatic vessels upon the
surface of the spleen, they were found very turgid, and the
fluid contained in them appeared of a much darker colour than
he had observed in any other lymphatic vessels ; on puncturing
one of the largest of these vessels, a small quantity of the fluid
it contained was received into a teacup, which was red, and
coagulated soon after being exposed to the air.

SECT. 69. Mr. Hewson soon discovered that a dog was an
unfavorable subject on which to make this experiment com-
pletely; because, in that animal, the splenic blood-vessels, both
arteries and veins, are divided into many branches, which enter
the spleen at some considerable distance from each other;
therefore the following experiment was made.

EXPERIMENT II.

SECT. 70. As soon as a bullock was killed, and the abdo-
men opened, a ligature was passed round the splenic vessels

2/2 SITUATION AND STRUCTURE

(which in this animal enter the spleen at its upper part) and
tied, the lymphatic vessels which accompany the artery and
vein were also included in the ligature, and as absorption con-
tinues so long as the animal remains irritable, the lymphatic
vessels, over the whole surface of the spleen, soon became
turgid, and were distinctly seen filled with a red fluid, so
highly coloured as equal parts of claret and water ; the larger
lymphatic vessel was then opened, and a quantity of the fluid
it contained was received into a teacup, which, on being ex-
posed to the air, soon coagulated.

EXPERIMENT III.

SECT. 71. A portion of this fluid was diluted with pure
serum, when the red colour seemed evidently owing to a
quantity of red particles, which were distinctly seen in very
considerable numbers.

SECT. 72. But lest it should be objected, that the red par-
ticles were contained in the serum, this experiment was care-
fully repeated.

EXPERIMENT IV.

SECT. 73. Another portion of the fluid received from the
lymphatic vessel was diluted with a weak solution of the
Glauber's salt, when exactly the same appearances were ex-
hibited as were formerly mentioned in experiments upon the
blood; so that there can be no doubt but that the red colour
of the lymph from the spleen is communicated to it by a
quantity of red particles of the blood.

SECT. 74. It may be objected to Experiment n, that the
animal, in being driven to the slaughter-house, might have re-
ceived some blow on the spleen, by which blood was extrava-
sated, or that extravasation might happen in the very act of
killing, and that this newly extravasated blood might be ab-
sorbed and found in the lymphatic vessels in the form of red
particles. $%<•

SECT. 75. To these objections we answer : first, that the
spleen is so well defended from external injuries, that it is
very improbable such an accident could happen. And secondly,
that if such an accident had really taken place, the lymph at
the greatest distance from the ligature should be of a redder

OF THE SPLEEN. 273

colour, which is not the fact ; for the colour of the lymph in
any of the lymphatic vessels of the spleen, as nearly as we can
determine, is the same ; but that which is nearest the ligature,
to a careless observer, seems to be of a deeper red ; but this
appearance is occasioned only by the quantity being larger
from the increased size of the vessel.

SECT. 76. These experiments were frequently repeated dur-
ing Mr. Hewson's lifetime, and many times since his decease,
and the appearances have been uniformly the same.

SECT. 77. That the spleen is the organ ordained by nature
for the more perfectly forming these red particles we shall
endeavour to prove in the next chapter (cxxxin).

(CXXXIIT.) Views more or less similar to Hewson's on the use of the
spleen, have been revived of late years by Tiedemann and Gmelin,3
Schultz,b and Donne. c On the contrary, the second Dr. Monrod ob-
served that the spleen of some fishes which have but few red corpuscles
in the blood, is as dark and comparatively as large as in man ; and that
in a sturgeon six feet long, with blood abounding in red particles, though
he found seven spleens, the largest was not bigger than a dried horse-
bean. Professor M tiller6 too objects, with reason, that the reddish colour
of the splenic lymph is not constant, and that the blood-corpuscles are
formed after the spleen has been extirpated. He also mentions that
in some fishes, myxine and the allied genus bdellostoma, the spleen is%
wanting ; and that its absence in the myxine had been noticed by feetzius.
It is curious that the blood of Mr. Yarrell's amphioxus lanceolatus/
said to be the lowest of the fishes, has lately been observed by Retzius,
Miiller, and de Quatrefages,g to be perfectly colourless, destitute of the
ordinary red corpuscles, and only containing a few colourless ones, like
the blood of the invertebrata.

Falconar rightly insists on Hewson's opinion,11 that the spleen is not
the only organ capable of forming the red particles. Indeed, Hewson
removed it from a dog without any ill effect ; * and in the 'Philosophical
Transactions' for 1667, vol. ii, p. 521, there is an account, by Oldenburg,
of a bitch that had her spleen cut out, and afterwards took a dog and
bred puppies.

a Recherches Experimentales sur la Di- e Physiology, tr. by Dr. Baly, vol. i, pp.

gestion, tr. par Jourdan, torn, ii, 572, 567, 1st edit.

p. 87, 8vo, Paris, 1827. f History of British Fishes, vol. ii, p. 468,
b Henle, Anatomie Generate, tr. par 8vo, Lond. 1836.

Jourdan, torn, i, p. 511. . s Annales des* Sciences Naturelles, Oct.

c Physiological Journal, No. 4, 8vo,Lond. 1845, p. 237, 3e Serie Zool. t. iv.

j'an. 1844, p. 118. h See Sect. 82, 85, 88, 108.

d The Structure and Physiology of Fishes ' Letter to Dr. Haygarth,p. 289 of this

explained, p. 37, folio, Edin. 1785. volume.

18

CHAPTER V.

CONTAINING AN ACCOUNT OF THE MANNER IN WHICH THE RED
PARTICLES OF THE BLOOD ARE FORMED, DEDUCED FROM THE
EXPERIMENTS AND OBSERVATIONS RELATED IN THE PRECEDING
CHAPTERS.

SECT. 78. IT hath been shown, in a paper delivered by the
late Mr. Hewson,1 and read June 17th and 24th, 1773, entitled,
" An account of the Figure and Composition of the Red Par-
ticles of the Blood, commonly called the Red Globules," that
these red particles are not globules, as was generally believed,
but that each particle is a compound body consisting of two
parts, viz. an external portion, which, from its resemblance to
a small bladder, is called a vesicle ; and an internal, contained
in the centre of this vesicle, which is called the central par-
ticle (cxxxiv); and that these particles while circulating in
the blood-vessels in their natural state, are not spheres, but
round and flat, resembling a piece of money (cxxxv).

SECT. 79. This fact has been proved by experiments ; first,
if the red particles of the blood be diluted with fresh serum,
and examined with a microscope, their flat figure may be im-
mediately discerned, and the shape of the particles remains
unaltered; but if a small quantity of water be mixed with
these particles, they are immediately transformed from a plane
to a sphere, the vesicle will gradually dissolve (cxxxvi), and
dissolving becomes transparent, at which time the central par-
ticle may be seen rolling from side to side like a pea in a
bladder ; the vesicle at length bursts, and the central particle
will be entirely disengaged from it ; but if a drop or two of a

. ' Vide Chapter I.

(cxxxiv.) See Notes en and cxxxvii.
(cxxxv.) See Note xcv, pp. 215-16.
(cxxxvi.) See Note xciv, p. 215.

FORMATION OF THE RED PARTICLES. 275

solution of any neutral salt be added to this mixture before
the bursting of the vesicle, it immediately becomes flattened,
and the particle of blood reassumes its original figure. In
the natural state of a particle of blood, the vesicle is collapsed,
and is in contact with, or adheres to, the central particle so
firmly as to retain the particle in the middle of it ; but when
water is added to the blood, and the vesicle becomes a sphere,
that union is broken, the central particle becomes loose in
the vesicle, and then only its motion can be distinguished
(cxxxvn).

SECT. 80. The figure and size of the particles of the blood
differ in different animals (cxxxvin) ; but the general con-
formation of vesicle and particle extends probably throughout
animal nature (cxxxix). That particles thus formed should
not be made by the mere agitation of the chyle in the lungs
seems probable ; that they are not, it shall be our business to
prove, and also that the lymphatic system and its appendages
are the organs employed by nature to do this office. By the
lymphatic system and its appendages we mean the lymphatic
vessels, the lymphatic glands, the thymus, and the spleen.

SECT. 81. At the first view it may seem extraordinary that
nature should have given so many and so complicated organs
to form a part only of the blood, when she effects other secre-
tions by organs apparently more simple ; but our surprise must
cease when we reflect, that upon a due formation of these par-
ticles, not only the various functions of the body, but also the
very existence of the animal, in a great measure, depends.
When we consider how liable these parts are to disease, by
which their offices would be impeded, we must necessarily
admire the goodness of the Author of our nature for so form-

(cxxxvu.) This description of the nucleus is evidently taken from
the blood-corpuscles of an oviparous vertebrate animal, and is not
applicable to those of mammalia. In short, the nucleus is a perma-
nent part of the red blood-corpuscle of oviparous vertebrata, and
only a temporary part of the red blood-corpuscle of mammalia: see
Note cii, pp. 222-3.

(cxxxvm.) See the Tables of Measurements, Note cxvin*,
pp. 237 et seq.

(cxxxix.) In mammals the nucleus of the red blood-corpuscle soon
disappears : see Notes en and cxxxvu.

276 FORMATION OF

ing these parts of our body, that the disease of a part should
not be attended with the destruction of the whole.

SECT. 82. The lymphatic vessels, which arise from every part
of the body, have already been described as performing the
office of absorption, or taking all those fluids into the body,
by which alone the animal is supplied with nourishment for its
preservation and growth, and the lymphatics not only do this,
but they also assist in forming the red part of the blood.

SECT. 83. Each lymphatic vessel is vascular, and, when
minutely injected, appears to have more blood-vessels than are
necessary for the nourishment and growth of that vessel. The
coat of each lymphatic is likewise muscular, and consequently
has a power of diminishing its capacity upon the application of
a stimulus. (See Note LXIV, p. 125).

SECT. 84. The lymphatic glands through which the lym-
phatics pass secrete a fluid which, when examined with a
microscope (chap. II, sect. 19), exhibits numberless small solid
particles, exactly resembling in size and shape the central
particles contained in the vesicles of the blood (CXL). The
lymphatic vessels which arise from the cells of the lymphatic
glands, into which the central particles are secreted, we have
called (chap. II, sect. 17) the excretory ducts of the lymphatic
glands, which convey the secreted particles into the lymphatic
vessels which pass through the gland, and from thence they
pass on through the thoracic duct into the blood-vessels.

SECT. 85. If we open a lymphatic vessel after it has emerged
from a lymphatic gland, we find not only a great number of
these central particles, but also many of the particles of the
blood completely formed (CXLI) ; that is, the central particle

(CXL.) See Notes en, cv, cxxu, and cxxxvu.

(CXLI.) Red corpuscles are certainly sometimes found in the lymphatic
vessels, and generally in those of the spleen of the horse and ox ; but
it would appear that the reddish colour of the splenic lymph is not
constant : see Note cxxxm, p. 2/3. Mr. Lane found the ruddy colour of
the horse's chyle due to the presence of red corpuscles ; and he and Mr.
Ancella observed imperfect blood-corpuscles, and attributed the rose-
colour of the lymph to them, in. the large lymphatic vessels. The
thoracic duct of the horse often appears as a coloured tube from the
number of these corpuscles in the chyle, which, as described in the
Appendix to the English edition of Gerber's 'Anatomy,' p. 93, I have

* Lectures on the Blood, Lancet, 1839-40, vol. i, p. 150 ; vol. ii, p. 152.

THE RED PARTICLES. 277

is surrounded by a vesicle. We may conjecture with a great
degree of probability, that the vesicle is either a secretion from
the internal coat of the lymphatic vessel, or that the lymphatic
vessel has a plastic power over its contained fluid, so as not
only to form a vesicle round the central particle, but also to
give it its red colour, for till the red vesicle is formed, the
central particle is evidently white.

SECT. 86. That a lymphatic vessel, after it has passed through
a lymphatic gland, contains lymph, red blood, and central par-
ticles, will not admit of a doubt to any one who will take the
trouble of making the experiment. How then are these red
particles formed, if not by the lymphatic vessels ?

SECT. 87. In Chap. II, sect. 19, we prove that central particles
are formed in the lymphatic glands; and from our finding
them presently afterwards taking on their vesicular portions
in the lymphatic vessels or being completely made, we cannot
doubt but that the lymphatic vessel gives them the red vesicle;
but in what manner this is performed, whether by a secretion
from the internal coat of the vessel, or by a plastic power of
the vessel itself over its contained fluid, is perhaps a circum-
stance among the arcana of nature too minute for human in-
vestigation.

SECT. 88. And it is amply sufficient to our purpose to prove
that the lymphatic vessels and glands are of themselves capable
of forming the red part of the blood.

SECT. 89. It will probably be asked, if the lymphatic glands
are given to form the central particles, how are those particles

generally found to be smaller, more irregular and less perfect in
shape, than the red corpuscles in the blood ; and the same observation
is applicable to the red corpuscles in the splenic lymph of this animal.
Dr. Simon's observations* on red corpuscles in the thoracic duct of
the rabbit and horse, are to. the sa'me effect. Schultz and Gurltb also
noticed the chyle of a reddish colour from the presence of blood-cor-
puscles, of which they suppose, with Simon, the formation to begin in
the chyle. The transition of the corpuscle of the chyle or lymph into
the red corpuscle of the blood seems now to be commonly admitted in
Germany : see Note cxxn, pp. 253-4. Dr. Davy informs me that he
found a small portion of red crassamentum in the thoracic duct of a
man who died suddenly of apoplexy.

a Animal Chemistry, tr. for the Syd. Soc. b Muller's Physiology, tr. by Dr. Baly,
vol. i, pp. 120-21, 8vo, Lond. 1845. vol. i, p. 563. 1st edit.

278 FORMATION OF

formed where the lymphatic glands are wanting, and yet the
red blood is perfect ? In answer to this, we beg leave to re-
peat what has been observed in a former chapter, that though
animals of the amphibious class have not that circumscribed
form of lymphatic gland which we find in the human body,
and in the bodies of quadrupeds, yet nature has in them con-
stituted a different apparatus to serve the same end, viz. a
network of lymphatic vessels on the meshes of the mesentery
found in the turtle. For, as we have already shown, the sup-
posed cellular structure of the lymphatic glands is by no means
necessary to constitute a lymphatic gland ; it is very probable
the ultimate branches of the lymphatic vessels in the mesentery
of the amphibia may perform the same office in that class of
animals which the small cells do in the human body, or in the
bodies of quadrupeds ; that is, as the central particles in those
animals which have lymphatic glands are formed in the small
cells of those glands, so nature in the amphibious class makes
the ultimate ramifications of the lymphatic vessels do that
office ; so that the same purposes of the animal economy may be
equally well effected, whether the parts composing a gland are
circumscribed in a proper membrane, or whether the same parts
are spread out over a large surface (CXLII).

SECT. 90. It may be objected by some that the appearance
of central particles may be a deception, for that appearance
may be seen in many fluids ; but the uniformity of their figure
in the same sort of animal, and the difference of their size and

(CXLII.) Falconar properly insists on Hewson's view, that the glands
are appendages to the lymphatic vessels, and that the central particles,
or lymph-corpuscles, may be formed in these vessels quite independently
of the glands ; thus anticipating the objection commonly urged against
his conclusion as to the office of the glands, from the observations of
Professors Burdach,a Mliller,b and Henle,c that the corpuscles are found
in the inferent lymphatic vessels. In the lymph of these vessels I, too,
have often seen the corpuscles ; but they are much more numerous in
the lymphatic and mesenteric glands, than in any other part of the
system of chyle or lymph vessels : see the Appendix to the English
edition of Gerber's 'Anatomy,' pp. 92, 95, 97-8.

a Traite de Physiologic, tr. par Jourdan, ° Anatomie Generate, tr. par Jourdan,
torn, ix, p. 453, 8vo, Paris, 1841. torn. i,pp. 506-7.

b Physiology, tr. by Dr. Baly, vol. i, p.
263. 1st edit.*

THE RED PARTICLES. 2/9

shape in different animals (CXLIII), will put this matter out of
dispute. In birds, as the common fowl for instance, the par-
ticles of the blood are oblong like a plum-stone (vide Plate V,
fig. 3), and the central particles found in the lymphatic glands of
that bird are also oblong, corresponding in every respect with the
central particle found in the vesicle of the blood of that animal.

SECT. 91. In chapter III it was observed that the structure
of the thymus gland is similar to that of the. lymphatic glands,
and that it secretes from the blood particles like those secreted
by the lymphatic glands ; in fine, in its office, that it is no more
than a large lymphatic gland. But why should the thymus be
large in the foetus, and as the animal increases in size, become
smaller and smaller until at length it quite disappears ? Or, in
other words, why does not the thymus, like the liver or pan-
creas, continue through life? The reason why the thymus is
larger during the early part of life, is, we conceive, that it may
act as an auxiliary to the lymphatic system, for the purpose of
forming more of the central particles of the blood than could
have been made by the lymphatic glands alone during that
time, when nature wants them most; for the human body
grows more, in proportion to its weight, from the second month
after conception to the end of the third year, than it does in
any future period of its existence of no longer duration; a
greater quantity of blood is therefore wanted and applied by
the constitution in the quick growth of the animal than is
ever afterwards applied to that purpose in the same time.

SECT. 92. If the thymus gland were wanting in the young
animal, the lymphatic vessels and glands must have been made
considerably larger than they now are, or out of proportion to
the other parts of the body; otherwise the animal could not
have been duly nourished, and the purposes of nature must
have been defeated; but by the assistance of the thymus, a
sufficient quantity of the central particles, to be converted into
blood necessary for the growth of the animal, are formed,
and nature at the same time preserves a just proportion in the

(CXLIII.) The similarity in the figure of the lymph-corpuscle in
different classes of animals, and the difference in shape between this
round corpuscle and the long oval nucleus of the blood-disc of birds,
is explained in Note cxxu, p. 253.

280 FORMATION OF

lymphatic system ; then, as the animal becomes larger, and of
consequence the lymphatic system more extended, that alone
and unassisted can now furnish a sufficient quantity of these
particles for the growth of the animal and repair of the con-
stitution ; the thymus being no longer necessary, and occupying
a space which by this time will become useful for other pur-
poses, the size of it will be gradually diminished, and its parts
absorbed into the habit.

SECT, 93. The thymus gland is placed in the chest, because
the space it fills is not wanted by the foetus. After birth,
when respiration takes place and the animal increases in size,
the growth of the lungs requires the cavity of the chest to be
enlarged, which is done partly by the absorption of the thymus,
but chiefly by the extension of the ribs.

SECT. 94. The thymus gland, then, we consider as being an
appendage to the lymphatic glands, for the more perfectly and
expeditiously forming the central particles of the blood in the
foetus, and in the early part of life (CXLJV).

(CXLIV.) Bisclioffa partially supports Hewson's view as to the use
of the thymus. From a series of interesting observations, Mr. Simon1'
includes its uses in the theory of fat-formation, concluding that
" the gland fulfils its use as a sinking fund of nourishment in the
service of respiration ;" and that, " what the gland sequestrates from
the circulation does, in gradually revisiting thither, accomplish those
chemical purposes in respect of respiration and temperature, which,
under other circumstances, are fulfilled by the effete products of active
animal tissues." He disbelieves, that the globules in the fluid can serve as
germs for the tissues or for the blood, because he declares it to be impossi-
ble that the globules, as such, can enter the lymphatic vessels without a
dissolution of the membrane lining the cells of the gland, and which,
he says, is a material of the most exquisite delicacy, rather a fine
boundary line than a membrane admitting of isolation.

With respect to Mr. Simon's conclusion, it may be asked, if it has
yet been proved that the purposes of respiration and temperature are
fulfilled by the effete products of the animal tissues? In man and
several animals, there is commonly a larger proportion of fat in the
chyle than in the fluid of the thymus or of the lymphatic system ; and, as
mentioned in Note LX, p. 88, it is at least probable that fat performs an
important part in nutrition and growth. As to the impossibility of the
globules passing into the lymphatic vessels, it is now generally admitted
that the multiplication of floating cells is rapidly effected by the minutest

a Mr. Simon's Essay on the Thymus, p. 9. b Physiol. Essay on the Thymus Gland,

pp. 90, 91, 38, 34, 4to, Lond. 1845.

THE RED PARTICLES. 281

SECT. 95. In chapter II we considered the lymphatic vessels
arising from the cells of the spleen as its excretory ducts, which
term, perhaps, when applied to lymphatic vessels, may be ob-
jected to by some, but we think not with reason; for if we
consider the office of an excretory duct, we shall find that there
is no more impropriety in calling these lymphatics excretory
ducts, than there is in using the term excretory duct to ex-
press that tube which conveys the secreted fluid of any other
gland to its place of destination. The excretory duct of the
liver conveys the bile into the duodenum, because that fluid is
required in the intestines for the purpose of digestion. So the

elementary molecules in a liquid cytoblastema, both produced by the
old cells. This liquid and the molecules might traverse the exquisitely
delicate membrane described by Mr. Simon, get into the lymphatic
vessels, and keep up the supply of globules there ; and it is not im-
possible that part of the membrane itself, as well as the highly developed
epithelium* of the intra-glandular lymphatic vessels, and the lymph-
globules themselves may be constantly in a state of dissolution and re-
novation.

But leaving these hypotheses, we come to the fact that the lymphatic
vessels of the thymus do carry a fluid, however it may get into them,
like that of the thymus, and pervaded by the same globules. At least
such is the result of Hewson's observations, which, as far as I know,
have never been refuted on this point ; and Sir Astley Cooper, whose
view of the use of the gland is mentioned in Note CXXVTI, p. 261, de-
clares that its lymphatic vessels are its absorbent ducts, and the carriers
of its fluid into the veins in the lower part of the neck. I must repeat
that a careful inquiry into the nature of the contents of these absorbent
vessels ought, as Hew son and Cooper believed, to form a leading part
of any researches concerning the office of the thymus.

In the Appendix to the English edition of Gerber's 'Anatomy,'
pp. 95-100, the reasons are detailed which induce me to believe, that
the fluid of the thymus differs only from that of the lymphatic glands
in containing more corpuscles ; that these have the characters of nuclei
or immature cells ;b and that both the lymphatic glands and the thymus
are organs for the elaboration of nutritive matter, the activity of the
thymus being most remarkable at that period of the economy when
growth and nutrition are most active: see Note cxxvn, p. 261.
Whether the ultimate destination of these embryo cells be simply to
serve as central particles for the formation of blood-corpuscles, as
Hewson supposed, or for the foundations, either mediately or imme-
diately, of cells concerned in growth and nutrition generally, as the
recent cell-doctrine would imply, is another question deserving of
further inquiry.

* See Note cxix*, p. 250. b See Note cxxn, pp. 223-4.

282 FORMATION OF

lymphatic vessels of the spleen convey the red particles of the
blood into the thoracic duct, and from thence they pass into
the blood-vessels, which is the place assigned to them by
nature, and from whence they are to be conveyed to the dif-
ferent parts of the body, to answer the purposes of nutrition
and vivification.

SECT. 96. That the spleen really does secrete the vesicular
portion of the red particles of the1 blood we have very con-
vincing proofs (CXLV).

SECT. 97. First, if the spleen be diseased, the body for a
time gradually wastes.

SECT. 98. Secondly, we have proved that vast numbers of
central particles made by the thymus and lymphatic glands,
are poured into the blood-vessels through the thoracic duct,
and if we examine the blood attentively, we see them floating
in it (CXLVI). Nature surely would not make so infinitely
many particles to answer no purpose ! What then becomes
of these particles after they are mixed with the circulating
blood ; are they immediately destroyed ? No. They are, we
believe, carried with the blood to the spleen, not that the
spleen has any elective attraction over them ; but that being
equally and uniformly diffused through the general mass of
blood, a due proportion of them is received by the spleen with
its arterial blood, and that when arrived there, the spleen has
a power of separating them from the other parts of the blood,
and of depositing them in the cells of that gland already de-

(CXLV.) See Note cxxxm, p. 273.

(CXLVI.) This passage is so clear, as completely to set aside the
claim made of late years by M. Mandla and others, to the discovery of
the pale globules of the blood. In that of mammalia, it is quite
evident that Hewson had seen these globules, and considered them in
all the vertebrata as lymph-corpuscles, a view which has recently been
revived. b Senacc also appears to have seen the pale globules in the
blood, and to have regarded them as belonging to the chyle.

That the lymph-globule is an immature cell, which may change in
the blood, and even in the thoracic duct or lymphatic vessels, into the
larger and more perfect pale cell of the blood, is very probable :
see Note cxxn, pp. 253-4.

a Anat. Microscop. liv. i, p. 8. fol. Paris, b See the App. to the English edition of
1838 ; et Anat. Gener. p. 252, 8vo, Gerber's Anatomy, pp. 15, 19.

Par. 1843. c Traite du Coeur, torn, ii, pp. 91, 661,

ed, 1749 ; and 2d ed. torn, ii, p. 279.

THE RED PARTICLES. 283

scribed; where the arteries which are spread out in form of
network upon the sides of the cells secrete from the blood the
vesicular portion, and that when thus perfectly made, the
lymphatic vessels which originate from the cells absorb them,
and convey them thence into the thoracic duct, and so into the
blood-vessels.

SECT. 99. That the spleen does secrete somewhat, is evident
from the change observable in blood drawn from the splenic
vein, which is distinguished by this remarkable property, that
it will not coagulate like blood taken from other veins (CXLVII);
the reason we apprehend is, because the coagulable lymph is
employed by nature in the formation of the red vesicle ; it re-
mains therefore fluid until the thinner parts have evaporated,
leaving* the red particles a dry mass.

SECT. 100. Fourthly, we have frequently examined blood
taken from the splenic vein, but could never distinguish any
central particles in it (CXLVIII).

SECT. 101. Fifthly, in every animal which has red blood a
spleen is found; but in those animals which have not red
blood the spleen is wanting (CXLIX).

SECT. 102. Lastly, we find that vast quantities of the red
particles of the blood are brought from the spleen by the
lymphatic vessels which originate in its substance, and for this
reason we have called these lymphatic vessels the excretory
ducts of the spleen.

SECT. 103. That the red particles of the blood are com-
pletely formed by the spleen we have therefore as strong

(CXLVII.) See Note cxxxn, p. 269, and Note CLI, p. 289.

(CXLVIII.) Contrary to the statement in the text, and to the similar
observation of Dr. Simon,3 I have more than once seen pale corpuscles
abundantly in the blood of the splenic vein. They did not differ in struc-
ture or size from the pale globules in the blood of the heart ; nor could I
observe any difference between the red corpuscles from the splenic vein
and from the heart, examined at the same time from the same animal ;
and the central spot5 was observed as well in the red corpuscles of the
splenic blood as in those from the heart. In one trial I saw the nuclei
as usual in blood-corpuscles taken from the spleen of a goose.

(CXLIX.) The spleen is said to be wanting in two or three cyclosto-
matous fishes : see Note cxxxm, p. 2/3.

* Animal Chemistry, tr. for the Syd. Soc. b See Note xcvi, p. 216.
vol. i, p. 202, 8vo, Lond. 1845.

284 FORMATION OF

proofs as we have that the liver secretes bile, or the testicles
semen; we find bile in the ductus hepaticus, semen in the
epididymis, and red particles of blood in the lymphatic vessels
of the spleen.

SECT. 104. It may then reasonably be asked, how is the
red blood formed when the spleen is taken out, if the spleen
is the viscus intended by nature to form the red blood ? This
objection will militate equally strong against any other use the
spleen is supposed to have ; for that the spleen may be taken
out, and the animal suffer but little inconvenience, by no
means prove it to be useless, but it proves that some other
part is capable of performing its office. Every philosopher
must entertain too exalted an idea of nature to believe that
any part of the creation is useless, much less could he suppose
a viscus in the human body, so large as this is, has no office
of importance assigned to it.

SECT. 105. Suppose, then, for a moment, we allow the spleen
to do the office assigned to it by the moderns, viz. that it pro-
duces some change on the blood preparatory to the secretion
of bile ; what must do that office when the spleen is wanting ?
for as the animal lives and is well nourished afterwards, if that
supposed change is absolutely necessary for the secretion of
bile, either some other viscus must do its office, or the bile, a
fluid so requisite for assimilating our food, could not be formed,
and the animal for want of being duly nourished must die.

SECT. 106. If we may reason from analogy, we should say,
that it is contrary to the established laws of the animal economy
to suppose the use of one organ or gland to be merely sub-
servient to another organ or gland in preparing the blood, in
order to render it fit for such organ or gland to do its office ;
it would be asserting that the liver which nature intended to
secrete bile could only do it by the intervention of the spleen ;
and yet if we allow that bile can be formed without the use
of the spleen,, we admit that intervention to be by no means
necessary. But to carry our analogy still farther, nature has
given to the animal body certain glands, and has assigned to
each peculiar offices, that is, she has endowed them with a
property of separating from the blood divers fluids, as different
from each other as they are from the mass of blood from out
of which they were originally separated.

THE RED PARTICLES. 285

SECT. 107. The lachrymal gland secretes the tears; the
salivary glands the saliva; the kidneys, urine; the testicles,
semen, &c. &c., without the intervention of any auxiliary gland.
If then a fluid so elaborated, and so different from anything
we find in the blood, as semen is, a fluid which has an office
of no less dignity than to perpetuate the whole race of animals,
can be formed from the blood by the vessels of the testis, with-
out any preparatory change being produced on it, may we not
reasonably conclude that the liver is capable of secreting bile
from the blood without any antecedent change being made on
it by the spleen? For to say that the blood must be pre-
pared by the spleen, before bile can be secreted from it by the
liver, is to deny that the liver, which is given to form bile, can
do the office which nature has intended it to perform.

SECT. 108. But if we allow the spleen to make the red part
of the blood, we can readily account for the reason why the
spleen may be cut out of an animal, and yet the animal survive,
and suffer but little inconvenience, for though the office of the
spleen is to form the red particles of the blood, yet it is not
the only organ in the body capable of doing that office ; for we
have already proved (sections 85 and 88) that the lymphatic
vessels do also form the vesicular portion ; the spleen, therefore,
is not the only organ capable of doing it. But nature has
given the spleen as an auxiliary to the lymphatic system, in
order to the more commodiously, expeditionary, and completely
forming the red part of the blood.

SECT. 109. If, then, the spleen be cut out, or its office ob-
structed by disease, nature has a. resource, in exciting the
lymphatic vessels to form a larger quantity of red particles than
they had ordinarily been accustomed to do, and these in pro-
portion to the exigencies of the habit ; but here nature does
not assign a new office to the lymphatic vessels, but only excites
them to exert, in a higher degree, a power of which they were
before possessed, and this notion is conformable to what we ob-
serve in other circumstances of the animal economy ; as when an
animal is fat and well nourished, the stomach is much longer
in performing its office than it is when emaciated by long
fasting, and its life is in danger from want of nourishment, or
than it is when the body is wasting by disease, witness the
surprising quantities of food the stomach will digest in a short

286 FORMATION OF THE RED PARTICLES.

time after a recovery from the smallpox, or a violent inflam-
matory fever ; under these circumstances, it is astonishing to
observe how much nature will exert herself, and how soon food
taken into the stomach will be digested, and applied to the pur-
poses of the constitution ; in like manner, most probably, if the
spleen be diseased or cut out, nature is capable of making the
lymphatic vessels exert themselves more powerfully in the exe-
cution of their office; or, on the contrary, if the lymphatic
system be diseased, the spleen is excited to form a larger
quantity of blood in order to make up the deficiency : thereby
the life of the animal will be less frequently endangered from
a partial disease.

SECT. 110. But how much soever the manner in which the
red vesicle is formed may be disputed, we think it cannot be
denied but that the office of the thymus and lymphatic glands
is clearly proved to form the central particles found in the
vesicles of the blood ; and though the operation of nature in
forming the vesicular portion is more obscure, yet the proba-
bility of its being performed in the manner we have related
will, we hope, be readily admitted.

SECT. 111. A system so new and so different as this is from
the opinions at present so generally entertained of the blood,
perhaps may meet with much opposition, and as no doctrine
should be admitted in philosophy till it has stood the test of
the most careful and accurate examination, it may therefore be
some time before this is universally allowed ; for as the experi-
ments are numerous, and some of them not easily made, few
but lovers of science will take the necessary pains to inquire
into them : but we will be bold to assert, that whoever repeats
these experiments will be amply rewarded for his trouble. We
shall add, that when these facts are viewed with candour, and
experiments of this kind are prosecuted with industry, they
may probably direct the way to discover many operations of the
animal economy that are at present considered among the
inexplicable arcana of nature.

SECT. 112. Having now finished the relation of the facts,
and the experiments to prove them, whether the conclusions
drawn from them are just we shall submit to the judgment of
the learned reader.

DETACHED PAPERS.

A Letter from the late Mr. William Hewsoh, F.R.S., and Teacher
of Anatomy in London, to Dr. John Haygarth, Physician in
Chester (CL).

My dear Sir, — I have now a little leisure, and shall endeavour
to fulfil my promise, by sending you a sketch of my observations.

The red particles of the blood, improperly called globules,
are flat in all animals, and of very different sizes in different
animals. In man, they are small, as flat as a shilling, and
appear to have a dark spot in the middle. In order to see
them distinctly, I dilute the human blood with fresh serum.
My predecessors, not having thought of this, could not see
them distinctly, and Leeuwenhoek in particular, imagining a
round figure fittest for motion, concluded they must be round
in the human body ; though he and others allowed, that, in
frogs, &c. where they viewed them distinctly, from the blood
being thinner, they were flat. Now, I prove that they are flat
in all animals. In the human blood, where these particles are
small, it is difficult to determine what that black spot is, which
appears in the centre of each. Some have concluded that it
was a perforation ; but in a frog, where it is six times as large
as in a man, it is easy to show that it is not a perforation, but,
on the contrary, is a little solid, which is contained in the
middle of a flat vesicle. Instead, therefore, of calling this part
of the blood red globules, 1 should call it red vesicles ; for each
particle is a flat vesicle, with a little solid sphere in its centre.

(CL.) From the * Medical and Philosophical -Commentaries, by a
Society in Edinburgh/ vol. iii, p. 87, 8vo, Bondon, 1775. In the
General Index to the present edition of Mr. Hewson's works, references
will be found to the pages in the Third Part of the * Experimental
Inquiries,' where the different points mentioned in this Letter are more
fully discussed.

288 A LETTER

I find that the blood of all animals contains vesicles of this
sort. In human blood there are millions of them, and they
give to it the red colour. But in insects they are white, and
less numerous in proportion than in man and quadrupeds. As
they are flat in all animals, I suspect that shape is a circum-
stance of importance ; but it can be altered by mixture with
different fluids. And I find that it is by a determinate quantity
of neutral salt contained in the serum that this fluid is adapted
to preserving these vesicles in their flat shape. For, if they be
mixed with water they become round, and dissolve perfectly ;
but add a little of any neutral salt to the water, and they
remain in it, without any alteration of their shape, and without
dissolving.

Now, when it is considered that the blood of all animals is
filled with these particles, we must believe that they serve some
very important purpose in the animal economy ; and since they
are so complicated in their structure, it is improbable they
should be made by mechanical agitation in the lungs or blood-
vessels, as has been suspected, but probably have some organs
set apart for their formation. This I shall endeavour to prove,
when I have explained their structure a little more particularly,
and mentioned the manner in which I exhibit it. I take the
blood of a toad or frog, in which they are very large, I mix
it with the serum of human blood to dilute it; I find them
appear all flat ; so they do in the blood-vessels of this animal,
as I have distinctly seen in the "web between its toes, whilst
the animal was alive, and fixed in the microscope. Their ap-
pearance in these animals is not unlike slices of cucumber. I
next mix a little of the blood with water, which immediately
makes them all round, and then begins to dissolve them whilst
they are round. I incline the stage of the microscope, so as
to make them roll down it, and then I can distinctly see the
solid in the middle fall from side to side, like a pea in a bladder.
A neutral salt added to them at this time brings them back
to their flat shape ; but if the salt be not added the water
gradually dissolves away the vesicle, and then the little sphere
is left naked. Such is the composition of these particles. I
have exhibited these experiments to a considerable number of
my acquaintance, who all agree in their being satisfactory.
The microscope I use is a single lens, and therefore as little

TO DE. HAYGARTH. 289

likely to deceive us as a pair of spectacles, which, as is allowed
by all who use them, do not disfigure objects, but only repre-
sent them larger.

From further experiments, I am convinced that the use of
the thymus and lymphatic glands is to make the solid middle
pieces ; and I can prove it in as satisfactory a manner as you
can do the use of any viscus in the human body ; that is, by
opening these glands, and examining the fluid contained in
their cells, which I find to be full of these little solids. I
moreover find that the lymphatic vessels take them up from
those glands, and convey them into the blood-vessels, which
carry them to the spleen, in whose cells they have the vesicles
laid over them ; so that the thymus and lymphatic glands make
the central particles, and the spleen makes the vesicles that
surround them. That this is the use of the spleen, appears
from examining the lymph which is returned from it by its
lymphatic vessels, which are its excretory ducts ; for that lymph,
contrary to what is observed in other parts of the body, is
extremely red.

But, besides having these glands set apart for making the
red vesicles of the blood, I find that they are also made in the
lymphatic vessels in different parts of the body, whose coats
have blood-vessels properly constructed for this secretion. So
that the thymus. and lymphatic glands are no more than ap-
pendages of the lymphatic system, for making the middle
particles ; and the spleen an appendage to the lymphatic vessels,
for making the vesicles which contain these middle particles.

I conjecture that it is the coagulable lymph which is con-
verted into this red part of the blood, from a curious fact that
has been long known ; namely, that the blood in the splenic
vein does not coagulate, when exposed to the air, as the blood
of other veins does (CLI) ; so that it seems to be robbed of its
coagulable lymph in passing through the spleen.

It is very remarkable that the spleen can be cut out of an

(CLI.) Mr. Hewson perhaps only had in mind the fact, mentioned
in Note cxxxn, page 269, that the blood of the splenic vein generally
coagulates less perfectly than other venous blood ; and not that the
blood of the splenic vein remains entirely fluid, until it dries, when ex-
posed to the air, as Mr. Falconar's statement, at page 283, sect. 99,
would imply.

19

290 A LETTER TO DR. HAYGARTH.

animal, and the animal do well without it. I made the ex-
periment on a dog, and kept him a year and a half, without
observing his health the least impaired. From this, some have
concluded the spleen to be a useless weight, which is absurd,
when we consider that all animals with red blood have it.
Therefore it is more consistent with what we know of the animal
economy, to conclude that since an animal can do well without
it, there is probably some part of the body that can supply its
place.

Insects have vesicles constructed in a similar way to ours,
but differing in colour. But insects have neither spleen,
thymus, nor lymphatic glands, and therefore in them probably
these vesicles are entirely fabricated in the lymphatic vessels.
But to us, and other of the more perfect animals, besides the
lymphatic vessels, nature has given those glands, that a proper
quantity of those important vesicles might be the better secured
to us, just as she has given us two ears, the better to secure
to us hearing through life, though we can hear perfectly well
with one.

Thus, my dear friend, I have given you a sketch of my new
opinions. I rather expect from this merely to gratify your
longing than to convince you, for the subject is too intricate
to be communicated in a letter ; but I make no doubt of proving
these positions when I have leisure to handle the subject more
fully. Adieu ! Believe me ever sincerely your friend,

WM. HEWSON.

LONDON; July 19, 1773.

The Operation of the Paracentesis Thoracis, proposed for Air
in the Chest, with some Remarks on the Emphysema, and on
Wounds of the Lungs in general ; by Mr. William Hewson,
Reader of Anatomy. Communicated by Dr. Hunter. Read
June 15, 1767 (CLII).

ALTHOUGH the emphysema has been of late more successfully
treated than formerly, yet I have been led to think that some-
thing further might be attempted towards a more certain and
a more speedy cure of that distemper.

The improvement which has occurred to me, and which I
shall venture to lay before the Society, is the operation of the
paracentesis thoracis, in order to let the air out of the chest ;
for that the confinement of the air in that cavity occasions the
worst symptoms in that disorder, and even death itself, I am
almost persuaded, partly from considering what the conse-
quences must be of a wound of the lungs, (for a wound there
is the common cause of the emphysema,) and partly from at-
tending to the symptoms of the disease; but chiefly from the
dissection of the body of a person who died under it.

The accident which most commonly gives rise to the em-
physema is a fractured rib, by which the vesicles of the lungs
being wounded, the air escapes through them into the cavity
of the thorax; but as the rib, on being fractured and pushed
inwards, wounds the pleura, which lines the ribs and the inter-
costal muscles, part of the air most commonly gets through
the pleura and those lacerated muscles into the cellular mem-

(CLII.) From the * Medical Observations and Inquiries, by a Society
of Physicians in London,' vol. iii, p. 3/2, 8vo, London, 1767. The
second Dr. Monro had previously proposed to let out the air from the
pleura in cases similar to those mentioned in this paper, as Hewson
has more fully explained in the beginning of the Appendix to the
First Part of the ' Experimental Inquiries,' pp. 91 etseq. of this volume.

292 OPERATION OF THE

brane that is on the outside of the chest, and from thence it
is diffused through the same membrane over the whole body,
so as to inflate it sometimes to an extraordinary degree. This
inflation of the cellular membrane has been commonly looked
upon as the most dangerous part of the disease ; how justly,
will appear in the sequel.

It is natural to suppose that the wound of the pleura and
intercostal muscles may sometimes be too small to suffer the air
to get readily into the cellular membrane and to inflate it, but
may confine a part of it in the cavity of the thorax so as to
compress the lungs, prevent their expansion, and cause the
same symptoms of tightness of the chest, quick breathing, and
sense of suffocation, which water does in the hydrops pectoris,
or matter in the empyema. So far we may conclude from
reasoning on the consequences of a wound of the lungs, and
from analogy.

And that it sometimes really happens that air is confined, and
produces these symptoms, appears probable from the histories
of such patients as have been emphysematous : of these, the
most remarkable that I have met with in my reading, are one
by M. Littre,1 another by M. Mery,2 a third by Dr. Hunter,8
and a fourth by Mr. Cheston.*

In M. Littre's case few symptoms are mentioned; we are
only given to understand that the patient, who had received a
wound in the side by a sword, could not breathe without
making the most violent efforts, especially during the latter
part of his disease : he died on the fifth day.

In M. Mery's case, we are informed that the patient had
the fourth and fifth of the true ribs broken by a coach passing
over his chest, that his respiration was much impeded from the
first, and became more and more difficult till he died, which
was on the fourth day after the accident.

In Dr. Hunter's case, the symptoms are more particularly
mentioned. This patient had received a considerable hurt on
his side by a fall from a horse. He had a difficulty of breath-
ing, which increased in proportion as the skin became elevated

1 Mem. de 1'Acad. Royale des Sciences, pour 1'annee 1713.
a Ibid.

3 Medical Observations and Inquiries, vol. ii.

4 Pathological Inquiries.

PARACENTESIS THORACIS. 293

and tense ; it was laborious as well as frequent. His inspira-
tion was short and almost instantaneous, and ended with that
catch in the throat which is produced by shutting the glottis ;
after this he strained to expire for a moment without any
noise, then suddenly opening the glottis, he forced out his
breath with a sort of groan, and in a hurry, and then quickly
inspired again; so that his endeavour seemed to be to keep
his lungs always full, inspiration succeeded expiration as fast
as possible. He said his. difficulty of breathing was owing to
an oppression or tightness across his breast, near the pit of the
stomach. He had a little cough, which exasperated his pain,
and brought up blood and phlegm from his lungs. Scarifi-
cations were made, which relieved him; the emphysema sub-
sided; his breathing became more and more easy, and he
recovered.

In Mr. Cheston's case, the man had received a blow on the
chest. He had a constant cough, bringing up, after many in-
effectual efforts, a frothy discharge lightly tinctured with blood;
he seemed to be in the greatest agonies, and under a constant
appearance of suffocation. His pulse was irregular, and some-
times scarcely to be felt; his face livid; and when he was
sensible, which was only now and then, he complained of a
pain in his head. On passing a bandage round his chest,
with a proper compress to prevent the discharge of air into the
cellular membrane, and to confine the motion of the thorax,
the patient cried out that he could by no means suffer it, and
that if it were bound so tight, he should burst. A strong com-
pression by the hand alone affected him in the same manner.
Scarifications were made to let out the air from the cellular
membrane; and these closing, others were made. Notwith-
standing bleeding, repeated scarifications, and other means, his
sense of suffocation and difficulty of breathing increased. On
the fourth day the air no longer got into the cellular mem-
brane ; when on a sudden inclining his head backwards, as it
were for the admission of more air than usual, his breathing
became more difficult and interrupted, he turned wholly in-
sensible, and soon after died.

M. Littre, M. Mery, and Mr. Cheston opened the bodies
of their several patients after death.

M. Littre in his, besides a wound of the lungs and a frac-

294 OPERATION OF THE

tured rib, found a considerable quantity of blood in the cavity
of the thorax, and was sensible of some putrid air escaping on
his first puncturing the intercostal muscles and pleura. The
wounded lobe was hard and black, and the other two of the
same side were inflamed.

In M.MeryV patient there was not any extravasated blood
in the cavity of the thorax, nor was there anything preter-
natural to be seen except the fractured ribs, the wound of the
pleura, and that of the lungs.

Mr. Cheston, in his subject, observed a fracture of the tenth
and eleventh ribs, and a wound of the lungs opposite to these
fractures. The lungs below the wound were livid; and, an
incision being made into them, their substance was found to
be more compact than usual ; but, excepting these appearances,
all the other parts were in a natural state, without any extra-
vasation, inflammation, or internal emphysema.

Now, were not the symptoms in those cases such as might
be expected to arise from air confined in the cavity of the
thorax ? I am inclined to believe they were, notwithstanding
that authors in general account for them otherwise, and among
the rest Mr. Cheston himself, though in one part of his re-
marks he seems indeed to point that way. «-,/«

On comparing these emphysematous cases, I say it seemed
probable to me that it was the air which was confined in the
chest that was the principal cause of the symptoms ; such as
the difficulty of breathing, the tightness of the chest, and the
sense of suffocation, which was so much increased by external
compression; and as in these symptoms this disease agreed
with the hydrops pectoris and the empyema, both of which are
relieved by the paracentesis thoracis, I was thence induced to
believe that this operation might be performed, for letting out
the air, with some probability of success.

But as in such cases no air had hitherto been actually dis-
covered in the cavity of the thorax, it therefore might be
doubted whether the symptoms were not owing to some other
cause ; such as the mere wound of the lungs (abstracting from
its letting out air), or an effusion of blood into the cells of
that organ,1 in consequence of the wound. ^ I thought it there-

1 This seems to have been the cause of the lividness and compactness which
Messrs. Littre and Cheston observed in the wounded lobes of their patients.

PARACENTESIS THORAGIS. 295

fore proper to try to ascertain, by the following experiments,
the effects of a simple wound of the lungs, and the effects of
air confined in the thorax ; and the rather as, in some of these
cases, the wound of the pleura and intercostal muscles appeared
so large, that it might be doubted whether the air could be
confined in the chest, when there seemed to be so free a pas-
sage from that cavity into the cellular membrane. .

• EXPERIMENT I.

I took a rabbit, and, pulling the skin of its chest to one
side, I pushed a sharp knife into the cavity of the thorax, and
moved it about so that I might wound the lungs ; then with-
drawing the knife, I let the skin slip back again, by which
means the wound of the skin was at some distance from that
of the intercostal muscles ; then applying a piece of lint, a
plaster, and a slight bandage to the wound of the skin, I ex-
pected to see the animal become emphysematous, but was dis-
appointed; and though I repeated the experiment three or
four times, I could not get the air to pass from the lungs into
the cellular membrane. On killing the animal, I observed
that the wounds of the lungs were surrounded by a small
ecchymosis, and were so closed (probably by the blood which
had been effused) that no air could escape.

EXPERIMENT II.

Having pushed a sharp knife into each side of the chest of
a dog, with the same precautions, and with the same intentions
as mentioned above, I then allowed him to run about the
house. This experiment I made at eight o'clock in the morn-
ing; about ten he appeared less lively, and about twelve seemed
to choose to be at rest, but had no difficulty of breathing nor
emphysema. In the evening he was as lively as before; and
was likewise so the next morning at eight o'clock, when I
killed him. On opening his abdomen, the diaphragm was not
depressed nor loose, as when air is let into the chest, nor did
any air escape on puncturing it. On opening the chest and
examining the lungs, I found that the wounds were small and
perfectly closed with a slight ecchymosis surrounding them.
On blowing into the lungs, the air did not escape through the
wounds.

296 OPERATION OF THE

From these experiments I concluded that, in order to let
the air out of the lungs into the cavity of the thorax, a punc-
ture or incision (on account probably of the effusion of blood
from the divided vessels) was improper ; and that, in the em-
physematous cases above mentioned, the emission of the air
must have happened from a superficial abrasion, or laceration
of the part.

EXPERIMENT III. *

I tried, by pushing a blunt probe into the chest of a rabbit,
and by moving it about, to produce such an emphysema by
laceration, but without effect.

EXPERIMENT IV.

I then punctured the chest of another rabbit, but so cau-
tiously as not to hurt the lungs ; and, having blown into it, I
immediately made a compression upon the wound with some
lint, a compress, and a bandage, in order to confine the air in
the cavity of the thorax. I then observed that the animal
breathed more frequently and laboriously. On removing the
compress, the air rushed out, and the animal gradually re-
covered its natural manner of breathing. It was then allowed
to run about the house for a few days, and seemed not the
worse for the operation.

EXPERIMENT V.

The same experiment was repeated on a dog, after tying him
down to a table ; but, when the air was blown into the thorax,
he struggled so much, and acted so strongly with his chest, as
to force it out again almost immediately; so that not being
able to manage him, I was obliged to desist without having
had an opportunity of observing what alteration was produced
on his breathing. I kept him about a week, and did not ob-
serve him at all affected by the wound.

I made no further experiments, being indeed almost con-
vinced from these that it was the air confined in the cavity of
the thorax, which had occasioned the violent symptoms in the
cases mentioned above, and not the mere wound of the lungs ;
and I must own, that if I was not perfectly convinced, it was
because no air, in such cases, had yet been found in the cavity

PARACENTESIS THORACIS. 297

of the thorax. But, not long after I had made these experi-
ments, the following case occurred, which fully satisfied me.

A young man, when the house was on fire, to save his life,
threw himself out of the window of a second floor, but frac-
tured his skull by the fall. He was taken up insensible, and
immediately put under the care of an eminent surgeon. In
the evening of the same day, my friend Dr. Stark (CLIII) ac-
quainted me that, the patient having become emphysematous,
and breathing with difficulty, I might now have an opportunity
(which he knew I wanted) of seeing such a case. Being at that
time engaged, I could not go till the next morning, when I
found that he had expired in the middle of the night. His
head had just been opened, and a considerable quantity of ex-
travasated blood had been found between the skull and dura
mater. On examining the chest, I found the external emphy-
sema but just perceptible, and that only on the right side.
On laying open the abdomen, the diaphragm was observed to
be depressed and loose on the right side, nearly as it appears
when in a dead body a wound is made into the cavity of the
chest. This I showed to the gentlemen present, and desired
that the body might be left in that condition till I could send
for Dr. Hunter, and when he came, the examination was con-
tinued. Upon puncturing the thorax, some air rushed out;
on laying the chest fully open, the lungs were found to be
much collapsed, but there was not any extravasated blood nor
lymph ; so that it was evident there had been a considerable
quantity of air in the cavity. We next examined the con-
taining parts of the thorax, and found the first rib (reckoning
from above) fractured near its middle, and the pleura there a
little lacerated. We then turned to the lungs, expecting to
find them wounded opposite to the fractured rib ; but, to our
surprise, no wound was discovered in that part. We then
looked over the surface of the lungs, and could see no wound ;
but observed on the concave under part of the lungs, where
they are applied to the diaphragm, two or three extravasations
of blood, and as many more of air, which had raised the mem-
branous coat of the lungs into vesications about the size of

(CLIII.) Dr. William Stark and his works are mentioned in Note LX.

298 OPERATION OF THE

one's nail. Next we blew into tfie lungs, and found that the
air escaped readily; and upon examining their surface once
more, whilst the air was getting out, we discovered a laceration
among the vesications just described, that is, on the middle of
that surface of the lungs which lies upon the diaphragm ; this
wound therefore was not only at a considerable distance from
the fractured rib, but remote from the other ribs also. These
facts were shown to several gentlemen then present, and seemed
to prove what I had supposed.

Now, from considering what the effects of a wound of the
lungs must be, from attending to the symptoms of the emphy-
sema, and from our having actually found air in the cavity of
the chest, may we not conclude that air is sometimes in em-
physematous cases so confined in that cavity as to compress
the lungs, disturb their functions, and even to be the cause of
death ?

And as the paracentesis thoracis has been frequently per-
formed with success for water, and for pus in the cavity of the
thorax, in both which cases the parts contained are generally
much diseased, may we not propose the same remedy for air;
and the rather, as we know that this fluid can be collected
there without any previous disorder of the lungs, and conse-
quently that the operation will be attended with a greater pro-
bability of success? We shall be confirmed in this opinion
when we consider that wounds penetrating the chest, without
doing much injury to the lungs, are far from being mortal ;
insomuch that many instances of cures of such wounds have
been observed within our memory, not to mention the numerous
cases of this kind related by authors.

In wounds of the lungs, therefore, whether occasioned by
fractured ribs or other causes, when symptoms of tightness and
suffocation come on, so far should we be from dreading the
emphysematous swelling of the cellular membrane, that we
should rather consider it as a favorable symptom, showing
that the air is not likely to be confined in the thorax ; and so
far should we be from compressing the wound, to prevent the
inflation or emphysema, that we should rather dilate it, (if not
large enough already,) or perform the paracentesis thoracis ;
and we may judge of the necessity of this operation from the

PARACENTESIS THOEACIS. 299

violence of the symptoms enumerated above, such as the op-
pressed breathing, &C.1 For when these symptoms are not
considerable, and the air gets out of the chest with sufficient
freedom, the operation then becomes unnecessary ; of this the
case in the Medical Observations is an evidence; for there the
inflation proceeded rapidly, and less air was retained in the
chest ; so that all that was necessary to be done, was to let it
out of the cellular membrane by scarifications, which accord-
ingly were successfully made.

Perhaps it may be inquired here, how the lacerated air-
vesicles, which once let out the air, should ever close ? To this
I should answer, that probably the inflammation, subsequent to
the wound of the lungs, closes or unites the divided air- vesicles
and small branches of the bronchia in such a manner as to
prevent their transmitting air ; much in the same way as the
wounds made in the cellular membrane by scarifications in
anasarcous cases are closed, or as those made in Dr. Hunter's
and Mr. Cheston's cases of the emphysema seem to have
been.2 And this appears more evident from observing, that
in Dr. Hunter's case the air appears not to have got into the
cellular membrane (or out of the wound of the lungs) after
the second day, by which time it should seem that the wound
of the lungs was sufficiently inflamed to produce the effect
above mentioned.

Is it not likewise probable, from the same principles, that
the penetrating wound of the chest occasioned by the fractured
rib, though at first large enough, may in some cases be so
closed by the subsequent inflammation as to prevent the air

1 It may not perhaps be improper to mention here, that we are not in every pene-
trating wound of the chest to suppose that the lungs are wounded, even though we
see that the air rushes in and out hy the wound. This I thought proper to observe,
because some, to whom this paper was communicated, objected that they had seen
patients in whom the air came out of the chest in expiration, so as to blow off the
dressings ; yet on compressing the wound, no difficulty of respiration followed. But
here it is probable that the lungs were not hurt, and that the air, which had been
thrown out by the wound of the thorax in expiration, had entered by it in inspi-
ration, an appearance which will be easily explained by those who are acquainted
with the structure and functions of the thorax. * "

- The closing of the scarifications, in Mr. Cheston's case, prevented the air from
getting entirely out of the cellular membrane, and he was therefore obliged to repeat
that operation to empty it completely.

300 OPERATION0 OF THE

getting from the thorax into the cellular membrane ? And is
not this conjecture strengthened by observing that in Mr.
Cheston's case the air, on the fourth day, no longer got into
the cellular membrane, and that soon after the patient died?

It has been observed that in gunshot wounds, where the
ball has passed through the lungs, and in other large penetrat-
ing wounds of the chest, the patient has breathed most easily
when the external wound has been covered, and has hardly
been able to breathe when it was opened. In these circum-
stances the difficulty of breathing seems to be owing to the air
getting into the cavity of the thorax in inspiration, instead of
entering the lungs by the trachea, so that the lungs are not
distended by the expansion of the chest; and the patient,
whilst such a wound is uncovered, is deprived of the use of the
lobes of that side, either partially or entirely, according as the
wound of the thorax bears a less or greater proportion to the
branch of the trachea of that side in which the wound is.
Moreover, as the difficulty of breathing in these cases is not
considerable whilst the external wound is covered, is it not
probable that the divided air -vesicles in most of these deep
wounds are closed, either by blood coagulated in the wound,
or extravasated into the neighbouring cells, by which means
the air is not transmitted through them as through the super-
ficial abrasions ? this seems probable from what was observed
in Experiments i and u.

The case of the person, whose body I opened, likewise shows
that the lungs may be lacerated, and air let loose, without any
wound penetrating the cavity of the thorax; for in that in-
stance the laceration was at a distance from the ribs, and was
produced by the violence of the concussion only. It therefore
intimates the necessity of the operation even in some cases
where there is no emphysema, though it must be acknowledged
it will not be easy to distinguish them.

As vomicae and ulcerations of the surface of the lungs are
attended with erosion and destruction of the air-vesicles, it
may at first sight seem probable that they may also be at-
tended with a discharge of air into the cavity of the thorax ;
but the probability will be much lessened when we consider,
that the inflammation which precedes the formation of pus is
likely to do here what it does in the cellular membrane ; that

PARACENTESIS THORACIS. 301

is, to condense the adjacent vesicles, and to make the sides of
the vomica, or ulcer, adhere to the inside of the parietes of the
thorax, thereby limiting the extent of what may be contained
in their cavities. Without this, it is probable air might be let
loose into the cavity of the thorax, and might produce the
symptoms above ascribed to it. For it is not uncommon to
see even pretty large branches of the trachea eroded by matter,
by which the air gets into the vomicae or ulcers ; of this my
ingenious friend Dr. Stark lately showed me an instance.
Whether air has ever thus been let loose into the cavity of the
thorax, so as to suffocate the patient, I cannot take upon me
to determine. But abscesses of the lungs, with adhesion to the
parietes of the thorax, have been known to be attended with
the emphysema; of this Palfyn mentions an instance,1 and
Dr. Hunter met with a case of the same kind. In these cases
the matter of the abscess had probably eroded the pleura and
intercostal muscles, and the air which got from the trachea
into the abscess, had escaped through the erosions into the
cellular membrane, and had inflated it.

Although the operation of the paracentesis thoracis is advi-
sable in most cases where air is contained in the cavity of the
chest ; yet some may be so complicated with other injuries,
that the operation, though in itself proper, may yet be unsuc-
cessful. But this remark may be unnecessary here, as the
same may be made of .every chirurgical operation; and as men
of experience will be cautious how they attribute to the remedy
that want of success which may be owing to another cause.

When the operation becomes necessary, the best place for
performing it, if the disease is on the right side, will be on the
fore-part of the chest, between the fifth and sixth ribs; for there
the integuments are thin, and, in the case of air, no depend-
ing drain is required. But, if the disease is on the left side,
it will be more advisable to make the opening between the
seventh and eighth, or eighth and ninth ribs, that we may be
sure of avoiding the pericardium. With regard to the size of
the wound, it may be proper to observe, that as large pene-
trating wounds of the chest are inconvenient on account of the
air's entering by the aperture in such a quantity as to prevent

1 Anatomic Chirurgicale, cap. xx, p. 2.

302 OPERATION, ETC.

the expansion of the lungs, a small wound will therefore be
eligible, and especially as the fluid requires not a large vent
for its discharge. Lastly, as to the manner of performing the
operation, I should think it more advisable to do it with a
knife, by a cautious dissection, than by the more coarse and
hazardous method, the thrusting in a trocar.

*

i

Fig.l

M, ^

H.Adlard.sc.

DESCRIPTION OF THE PLATES.

PLATE I.

FIG. 1. Exhibits the more superficial Lymphatic Vessels of
the lower Extremity.

A, The spine of the os ilium.

B, The os pubis.

c, The iliac artery.

DJ The knee.

E, E, F, Branches of the crural artery.

G, The musculus gastrocnemius.

H, The tibia.

i, The tendon of the musculus tibialis anticus.

On the Outlines.

a, A lymphatic vessel belonging to the top of the foot.

b, Its first division into branches.

c, c, c} Other divisions of the same lymphatic vessel.

d, A small lymphatic gland.

e, The lymphatic vessels which lie between the skin and
the muscles of the thigh.

fjfj Two lymphatic glands at the upper part of the thigh
below the groin.

g,g, Other glands.

h, A lymphatic vessel which passes by the side of those
glands without communicating with them; and, bending to-
wards the inside of the groin at i, opens into the lymphatic
gland k.

I, I, Lymphatic glands in the groin, which are common to

304 DESCRIPTION OF PLATES.

the lymphatic vessels of the genitals and those of the lower
extremity.

my n} A plexus of lymphatic vessels passing on the inside of
the iliac artery.

N.B. The lymphatic vessels appear in these plates more regularly cylindrical than
they are represented by Nuck, Ruysch, and others, in whose plates such vessels are
painted more like chains of vesicles than I have ever seen them.

FIG. 2. Exhibits a Back View of the lower Extremity, dissected
so as to show the deeper-seated Lymphatic Vessels which
accompany the Arteries.

N.B. This extremity was dried before the plate was made from it, and the muscles
are therefore much shrunk.

A, The os pubis.

B, The tuberosity of the ischium.

c, That part of the os ilium which was articulated with the
os sacrum.

D, The extremity of the iliac artery appearing above the
groin.

E, The knee.

F, F, The two cut surfaces of the triceps muscle, which was
divided to show the lymphatic vessels that pass through its
perforation along with the crural artery.

G, The edge of the musculus gracilis.

H, The gastrocnemius and soleus, much shrunk by being
dried, and by the soleus being separated from the tibia to ex-
pose the vessels.

i, The heel.

K, The sole t)f the foot.

L, The superficial lymphatic vessels passing over the knee,
to get to the thigh.

On the Outlines.

M, The posterior tibial artery.

a, A lymphatic vessel accompanying the posterior tibial
artery.

b, The same vessel crossing the artery.

c, A small lymphatic gland, through which this deep-seated
lymphatic vessel passes.

DESCRIPTION OF PLATES. 305

d, The lymphatic vessel passing under a small part of the
soleus which is left attached to the bone, the rest being
removed.

e, The lymphatic vessel crossing the popliteal artery.

ft g> h, Lymphatic glands in the ham, through which the
lymphatic vessel passes.

i, The lymphatic vessel passing with the crural artery
through the perforation of the triceps muscle.

k, The lymphatic vessel after it has passed the perforation of
the triceps, dividing into branches which embrace the artery /.

m, A lymphatic gland belonging to the deep-seated lym-
phatic vessel. At this place those vessels pass to the fore part
of the groin, where they communicate with the superficial
lymphatic vessels.

n, A part of the superficial lymphatic vessels appearing on
the brim of the pelvis.

20

306 DESCRIPTION OF PLATES.

PLATE II,

Exhibits the Trunk of the Human Subject, prepared to show
the Lymphatic Vessels and the Ductus Thoracicus.

A, The neck.

B, B, The two jugular veins.
c, The vena cava superior.

D, D, D, Vj The subclavian veins.

E, The beginning of the aorta pulled to the left side by
means of a ligature, in order to show the thoracic duct
behind it.

r, The branches arising from the curvature of the aorta.

G, G, The two carotid arteries.

H, H, The first ribs.

i, i, The trachea.

K, K, The spine.

L, L, The vena azygos.

M, M, The descending aorta.

N, The coeliac artery dividing into three branches.

QJ The superior mesenteric artery.

p, The right crus diaphragmatis.

Q, Q, The two kidneys.

R, The right emulgent artery.

s, s, The external iliac arteries.

g, d, The musculi psose.

T, The internal iliac artery.

u, The cavity of the pelvis.

x, x, The spine of the os ilium.

Y, Y, The groins.

a, A lymphatic gland in the groin,, into which lymphatic
vessels from the lower extremity are seen to enter.

b, b} The lymphatic vessels of the lower extremities passing
under Poupart's ligament.

c, c, A plexus of the lymphatic vessels lying on each side of
the pelvis.

d, The psoas muscle with lymphatic vessels lying upon its
inside.

3oiiapr, del1

ILAdLii-d.sc

DESCRIPTION OF PLATES. 307

e, A plexus of lymphatics, which having passed over the
brim of the pelvis at c, having entered the cavity of the pelvis,
and received the lymphatic vessels belonging to the viscera
contained in that cavity, next ascends, and passes behind the
iliac artery to g.

fj Some lymphatic vessels of the left side passing over the
upper part of the os sacrum, to meet those of the right side.

g, The right psoas muscle, with a large plexus of lymphatics
lying on its inside.

h, ht The plexus lying on each side of the spine.

i, i, i, Spaces occupied by the lymphatic glands.

k, The trunk of the lacteals lying on the under side of the
superior mesenteric artery.

/, The same dividing into two branches, one of which passes
on each aide of the aorta ; that of the right side being seen to
enter the thoracic duct at m.

m, The thoracic duct beginning from the large lymphatics.

n, The duct passing under the lower part of the cms dia-
phragmatis and under the right emulgent artery.

o, The thoracic duct penetrating the thorax.

p, Some lymphatic vessels joining that duct in the thorax.

q, The thoracic duct passing under the curvature of the
aorta to get to the left subclavian vein ; the aorta being drawn
aside to show the duct.

r, A plexus of lymphatic vessels passing upon the trachea
from the thyroid gland to the thoracic duct.

308 DESCRIPTION OF PLATES.

PLATE III,

Exhibits the upper part of the Thoracic Duct, the Lymphatic
Vessels of the upper part of the Chest and Arms, and of
the lower part of the Neck.

A, The neck.

B, B, The two shoulders with the pectoral muscles turned
over them.

c, c, The arms.

D, D, The cut ends of the clavicles.

E, E, The extremities of the first two ribs.

F, F, The subclavian muscles.

G, G, The ribs.
H, The trachea.

i, The aorta ascendens.

K, The aorta descendens.

L, The trunk of the carotid, and subclavian artery of the
right side.

M, The left carotid.

N, N, The left subclavian artery.

o, The vena cava superior.

p, p, The trunks of the subclavian and jugular veins.

Q, The right subclavian vein.

R, The right jugular vein.

s, The left subclavian vein.

T, The left jugular.

0, The thoracic duct passing on the right side of the de-
scending aorta K, behind the ascending aorta i, and behind
the lower part of the left carotid artery M, and then appearing
at b.

b, The upper part of the thoracic duct lying between the
left carotid and the left jugular vein, and passing behind that
vein downwards and outwards towards the angle between the
left jugular and the left subclavian.

c, The extremity of the thoracic duct entering the angle
between the left jugular and the left subclavian vein.

DESCRIPTION OF PLATES. 309

dj d, Two of the trunks of the lymphatics of the left arm
lying upon the outside of the chest, and passing under the
subclavian muscle F, and the subclavian vein s, the clavicle
itself being removed, and its cut extremity seen at D.

e, A trunk formed by the lymphatics of the upper extremity,
which trunk joins the extremity of the thoracic duct e, and
enters the angle between the left jugular and the left sub-
clavian vein.

f} Lymphatics from the thyroid gland running upon the
trachea, and passing under the aorta to get to the thoracic
duct, just where that duct enters the veins.

g, g, A trunk of the lymphatics of the right arm lying on
the outside of the right brachial artery.

h, A branch of this trunk making a network on the outside
of the thorax just under the clavicle.

i, That network passing under the right subclavian vein Q,
and under the subclavian muscle F, the clavicle itself being
removed.

k, The common trunk both of that plexus and of all the
other lymphatics of the upper extremity of the right side,
which trunk lies between the right subclavian artery and vein,
and passes into the angle between the right jugular and the
right subclavian.

/, The trunk of the lymphatics of the right side of the neck
lying on the outside of the right jugular vein, and passing into
the angle between that vein and the subclavian of the same
side.

m, One of the lymphatics of the right side of the thyroid
gland going under the right jugular vein.

310 DESCRIPTION OF PLATES.

PLATE IV.

FIG. 1, exhibits a Back View of the Fore-arm and Hand.
The Preparation from which this View was taken having
been previously dried, the Muscles appear very slender.

A, The hand.

B, The lower extremity of the radius,
c, The lower extremity of the ulna.

D, The muscles on the back of the fore-arm turned aside
to exhibit a deep-seated lymphatic vessel, which perforates the
interosseous ligament to get to the fore part.

E, The olecranon.

On the Outlines.

a, 0, a, Lymphatics appearing on the back of the fore-arm,
immediately under the skin.

b} Some of the lymphatics bending over the upper extremity
of the radius to get to the fore part of the arm.

c, A lymphatic passing over the ulna, immediately under
the olecranon, and under the inner condyle of the os humeri,
to get to the fore part of the arm.

dt A lymphatic which has penetrated the muscles, perforates
the interosseous ligament, and gets to the fore part of the arm
near the radial artery.

FIG. 2, exhibits a fore View of the upper Extremity. This
Plate was likewise made from a dried Preparation, and
the Muscles therefore appear very small. It has a
peculiarity in the ulnar artery running over the muscles
instead of under them.

A, The scapula.

B, The clavicle.

c, The extremity of the brachial artery.

D, The muscles lying on the inside of the arm.

fLA 1 '

Pig 2.

BLMlarl.sc.

DESCRIPTION OF PLATES. 311

E, The inner condyle of the os humeri.

F, The lower extremity of the radius.

On the Outlines.

a, A lymphatic vessel which lies in the cellular membrane
immediately under the skin, and passes up on the inside of
the arm to the axillary glands.

b, Superficial lymphatic vessels passing over the muscles
from the back of the fore-arm, and likewise over the biceps to
the glands in the axilla.

c, A superficial lymphatic from the back of the fore-arm.

d, A gland through which it passes.

e, The lymphatics from the anterior and the posterior part
of the fore-arm uniting.

fyf, Lymphatic glands in the axilla.

g, A deeper-seated lymphatic vessel lying close to the radial
artery, which it accompanies all the way to h.

h, The deep-seated lymphatic vessel passing under the inter-
osseous and ulnar arteries, and appearing again on the arm
at i.

i, The deep-seated lymphatic vessel lying close to the
brachial artery.

k, k, Two small lymphatic glands through which it passes.

/, The same vessel now become much larger, and passing
under a branch of the artery and some cellular membrane, and
appearing at m.

m, The trunk of the deep-seated lymphatic vessels passing
upwards to the axilla, where it enters the glands /,/.

/, /, Three axillary glands, which are common both to the
superficial and the deep-seated lymphatic vessels.

Note. In the figures of this plate the lymphatic vessels are shown somewhat
larger in proportion to the limb than natural.

312 DESCRIPTION OF PLATES.

PLATE V.

A comparative View of the Flat Vesicles of the Blood in dif-
ferent Animals, exhibiting their Size and Shape (CLIV)
as they appear through a Lens ^ of an inch focus.

FIG. 1, Their size in an ox, a cat, an ass, a mouse, and a
bat.

FIG. 2, Their size in a man, in a rabbit, a dog, and a
porpoise (CLV).

FIG. 3, Their size in birds; viz. a pigeon, a hen, a chaffinch,
and a duck.

FIG. 4, Their size in a chick, from the egg, on the sixth day
of incubation (see Note cxvi, p. 233).

FIG. 5, Their size in the common fish, as the salmon, carp,
eel.

FIG. 6, Their size in a full grown viper and in a turtle.

FIG. 7, Their size in a small viper taken from the belly of
its mother (see Note cxvi, p. 233).

FIG. 8, Their size in a slow-worm (CLVI).

(CLIV.) See the copious Tables of Measurements of the blood-cor-
puscles of vertebrate animals, Note cxvm*, pp. 237 et seq. ; and the
Notes there referred to on the size and shape of the corpuscles.

(CLV.) The central spot in the blood-corpuscles of mammalia should
not be confounded with the nucleus of the blood-corpuscle of oviparous
vertebrata ; see Notes xcvi and on.

(CLVI.) The Tables of Measurements, at p. 242, show that the red cor-
puscle of the slow- worm (anguis fragilis) is a narrower ellipse than either
the corpuscle of the snake, of the adder, or of the boa, as explained in
my Paper on the Blood-Corpuscles of Ophidian Reptiles. a Other well-

a Proceedings of the Zoological Society, August 9, 1842.

fif. 7.

• •

• « *

Fig.10.
+ * •

DESCRIPTION OF PLATES. 313

FIG. 9, Their size in a frog.
FIG. 10, Their size in a skate.
FIG. 11, Their size in a lobster.

FIG. 12, The vesicles of the same lobster, as they appear
after being a short time exposed to the air.

FIG. 13, The size of the globules of milk.

marked examples of a difference of shape in the blood-corpuscles of
nearly allied animals occur among birds : the snowy owl, the passenger
pigeon, the butcher bird, are all distinguishable by the longer oval
form of their blood-corpuscles from their congeners. See Note xcvin,
pp. 218-19.

314 DESCRIPTION OF PLATES.

PLATE VI,

FIG. 1, Exhibits the Lymphatic Vessels of the lower Extremity,
injected with Mercury, passing through a Cluster of
Lymphatic Glands taken from the Groin. The Arteries
and Veins were not injected in this Preparation.

0, 0, 0, 0, 0, 0, 0, «, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, the lymphatic
vessels.

b, by b, by by by by by by the lymphatic glands seen of different
sizes and shapes, with the lymphatic vessels passing through
them.

A,B,C,D,E, Lymphatic glands that have a cellular appearance.

F, G, Lymphatic glands evidently formed of convoluted lym-
phatic vessels ; these likewise show the manner in which the
vessels enter and pass through the glands.

H, H, Lymphatic vessels running to the edges of the two
lymphatic glands not injected.

1, i, Lymphatic glands uninjected. .

FIG. 2, Exhibits a Lymphatic Vessel that forms three small
Lymphatic Glands.

A, A lymphatic vessel.

B, A gland made by a subdivision of the trunk A into nine
or ten branches, which are convoluted; these reuniting, form
the lymphatic vessel c.

c, A lymphatic vessel ascending to form the gland D.

D, A lymphatic gland.

E, A lymphatic vessel formed by the union of the lymphatic
vessels that composed the gland D, which divides into the two
branches F and G.

F, The lymphatic vessels subdivided into small branches to
form the third lymphatic gland H.

H, The third lymphatic gland.

Fig.2

Fig". 3.

Ja3 Turner del.

DESCRIPTION OF PLATES. 315

i, A lymphatic vessel formed from the gland H, which passed
on to communicate with other lymphatic vessels, not expressed
in this plate.

G, A lymphatic vessel.

FIG. 3, Exhibits the manner in which a single Lymphatic Vessel
enters and passes through a Lymphatic Gland.

a, The trunk of a vessel filled with mercury.

b, The division of the trunk into four branches before it
enters the gland.

c, The gland, with the lymphatic vessels passing through it.

d, The lymphatic vessels having passed through the gland,
form four vessels on the opposite side, to which they had
entered the gland. These vessels unite to form the trunk e.

<?, The lymphatic vessel, having passed through the gland,
is become larger than before it entered the gland.

FIG. 4, Exhibits a Lymphatic Gland with the Lymphatic Vessels
injected with Mercury, in which the Subdivision of the
larger Vessels into smaller Branches, running in a ser-
pentine Direction through the Gland, is apparent to the
naked Eye.

FIG. 5, Exhibits Lymphatic Vessels and Glands, taken from
the Axilla in which the Subdivision of the Trunks into
Branches, and their frequent communication with each
other, may be traced distinctly.

a, a, a, The trunks of five lymphatic vessels that come from
the arm into the axilla, and as they ascend, divide into many
branches, which make frequent anastomoses, and then form
the plexus A.

A, A plexus of lymphatic vessels dividing into two parts b, c.

316 DESCRIPTION OF PLATES.

b, A cluster of lymphatic vessels that run parallel to each
other.

d, Lymphatic vessels that surrounded the artery, and passed
on to lymphatic glands not represented.

etftyt Lymphatic vessels that form the gland h.
i, The lymphatic vessel arising from the gland h.

c, A plexus of lymphatic vessels communicating frequently
with each other, and then Ascending, divides into the branches
*, /, /.

k, /, /, Lymphatic vessels that passed on to open into the
angle between the jugular and subclavian vein, on the right
side, without entering any lymphatic gland in their passage.

All the objects in this plate arc exhibited of a reduced

PLATE VL

Jas Turner, del

DESCRIPTION OF PLATES. 317

PLATE VII,

Exhibits a reduced view of a part of the Mesentery of a Turtle
injected. The Arteries were filled with red Wax, the
Veins with black, and the Lacteals with Mercury.

The mesenteric artery and vein, as they pass on to the gut
between two folds of the peritoneum, divide into branches that
make frequent anastomoses. These larger vessels leave spaces
that resemble a network, and form meshes of different sizes.
These in the unprepared state are transparent ; but when the
blood-vessels are minutely injected, we observe several small
arteries and veins ramifying to the utmost minuteness. And
from the transparency of the peritoneum, we can here distinctly
trace the artery terminating in the vein by continuity of canal.
It is on these meshes that the lacteals, as they come from the
gut upon the mesentery, divide into innumerable branches, that
communicate frequently with each other, and form a beautiful
plexus of lacteal vessels. That in its office, we consider
analogous to the lymphatic glands, seen in the mesentery of
other animals.

0, a, a, a, a, The outline of the mesentery.

by b, by The intestine.

c, The artery.

d, The vein.

e, The lacteals surrounding the artery and vein.

A, A mesh of the mesentery on which a plexus of lacteal
vessels is delineated.

318 DESCRIPTION OF PLATES.

PLATE VIII.

FIG. 1, Exhibits the Chest of a Still-born Child, opened to
show the Situation of the Thymus Gland.

a, a, a, a, The skin, muscles, and ends of the ribs, the
sternum and cartilaginous part of the ribs being removed.

b, b, b, by The edge of the diaphragm.

c, Cj The right and left lung.
dj The pericardium.

e, The heart.

ft Part of the first bone of the sternum.

9> 9> 9) The thymus gland.

FIG. 2, Exhibits the Size and Figure of the Vesicles of the
Human Blood, as they appeared in the microscope when
viewed through a lens the ^ of an inch focus. The solid
central particle, as formerly described, is seen distinctly
in the centre of each vesicle (see Notes xcvi and en).

FIG. 3, Represents the Size and Figure of the Particles (see
Note cxxii, p. 253) found in a Lymphatic Gland, taken
from the Human Body, as they appeared viewed by a
strong sun-light, through the same lens used in the former
experiments.

FIG. 4, Represents a portion of a Lymphatic Gland from the
Human Subject greatly magnified, in which the cells of
the Lymphatic Gland are shown.

d © ©

TV T> T

. •

ro <*

:^. • •

Cr^ CL. '

DESCRIPTION OF PLATES. 319

FIG. 5, The Size and Figure of the Vesicles of the Blood, taken
from a common fowl.

FIG. 6, Exhibits the Size and Form of Particles (see Note
cxxii, p. 253) taken from a Lymphatic Gland, found on
the neck of the fowl whose blood is expressed in fig. 5.

Note. All the Experiments were made by a clear daylight, and the objects viewed
through the same lens, viz. ^ of an inch focus, except Plate vin, fig. 4, which was
examined with a lens the 3, of an inch focus.

GENERAL INDEX,

ABERNETHY, Mr., on the acquisition of
our knowledge of the absorbent
system, xxii.

on the parts of the blood, xliii.
on the mesenteric glands of the

whale, 250.

Absorption, supposed discovery that the
lymphatic vessels are the exclusive
agents of, xxii.
by lymphatics, 142.
may occur independently of them, 142.
whether performed by veins, 171,

172, 177, 180.

supposed to take place by small ori-
fices, 172, 179, 194.
in the placenta, 175.
KAUW BOERHAAVE'S experiments

on, 176.

agency of cells in, 179.
independently of blood-vessels or

lymphatics, 179, 182.
on the manner in which it is per-
formed, 187.

hypothetical account of, 194.
arguments that it is performed by lym-
phatics and not by the veins, 199-204
of pus, and of the fluid of dropsy, 171.
of water injected into the body, 171.
of blood so injected, 172.
Acetic acid, effect of, on the nucleus of
the red corpuscles of the blood, 225,
and on lymph-corpuscles, 253-4.
Acid, carbonic, effect of, on the coagula-
tion of the blood, 20.
Acids, effects of on the blood-discs, 230-31.
Acini of glands, 191.
ADDISON, Mr., referred to, 14.
Adhesions from inflammation, Dr. HUN-
TER'S description of the matter of,
xxxvii.

Aggregation of the blood-discs of man in

health, 221 ; further in buffy blood

of man, and in the horse's blood,

221. See Buffy Coat.

Agitation, effect of, on the coagulation of

the blood, xxxiii, 15, 16.
Air, effect of, on the coagulation of the
blood, xxxiii, 18, 19, 20, 21, 25,
61, 64, 72. See Coagulation.

Air, effect of, on the colour of the blood,
7, 9, 10, 71. See Blood.

effect of on the blood-corpuscles of
the lobster, 234. See Corpuscles.

in the chest, HEWSON'S paper on, 291.

escape of from chest not always a
proof of a wound in the lungs, 299.

hypothesis of nitre in the, 11.
AJLBINUS, considered villi not existing in
the large intestine, 188.

on the papillae of the tongue, 193.
Albumen, distinguished by the want of
fibres from fibrin, xlv.

and fibrin probably isomerical sub-
stances, 30 ; but said to differ in
their elements, 31.

liquid, said to be a salino-alkaline
solution of fibrin, 31.

probably convertible into fatty mat-
ter, 86. See Fat.

supposed conversion of into fibrin
by the red corpuscles of the blood,
235. See Fibrin.

ALISON, Dr., on the fibres of fibrin as dis-
tinguishing it from albumen, xlv.

on buffy blood, 34. See Buffy Coat.

on the effect of serum on the coagu-
lation of blood, 44.

Alkalies, action of, on lymph -corpuscles
and pale cells, 254 ; and on the red
corpuscles of the blood, 230-31.
America, Mrs. HEWSON goes to, xxi ; her

children there, xxi.

Amphibia, lymphatic system in, reading
of HEWSON'S papers on, xxiii.

on the discovery of the lymphatic
system in, 91. See Lymphatics.

lymphatics of, 121.

description of the lymphatic system
of, 147.

size of the blood-corpuscles of, 219.

formation of the corpuscles of lymph
in the lymphatic network of, 278.

sizes of the corpuscles of the blood

and lymph of. See Measurements.

Amphioxus, colourless blood of, 234, 273.

Ampullula of the lacteals in the villi, 181 ;

of intestinal villi, 187, 189, 190,

191, 192.

21

333

GENERAL INDEX.

Amputations, coagulation of thcbloodiu,25
Anasarca. Account of, 197, 198.
ANCELL, Mr., his table referred to on the

coagulation of the blood, 13.
his table on the properties of the

blood-discs cited, 231.
on turbid serum, 86.
on blood-corpuscles in the lympha-

tics, 276.
AXDKRSON, Dr., on the state of the fibrin

in the circulating: blood, 32.
AXDRAL, referred to, 2, 267.

on the serum of buffy blood, 38.
on the Mood of the horse, 40.
Aneurism, Dr. HUNTER'S description of a
clot in, xxxvi; how he supposed
that bone is eroded in an aneurism,
xxxvU, 183-4.

coagulation of the blood in, 25.
Animal heat, how high in some cases, 27*
.\ni\uals frozen and revived, 19.
Antelopes, coagulation of the blood in
hunted ones, 21. See Coagulation.
Appendix on the discovery of the lymphatic
ajekm in oviparous vertebrata, 91.
ARBITHXOT, Dr., on the coagulation of

the blood, xxviii-xxix.
on whiteorchylous blood or serum, 85.
ARISTOTLE, on the coagulation of the

blood, xxv. See Coagulation.
on the ert'tvt of removing the fibrin
from the blood, xxv. See Fibrin.
on the effect of cold on coagulation

of the blood, 17. See Cold.
Arterial and venous blood, colour of, 7 , 8, 1 0.
Arteries, their action in inflammation sup-
posed to convert the red corpuscles
of the blood into the bufly coat,
xxxi. Sat Buffy coat.
amputated, coagulation of blood in, 25.
on the stopping of bleeding from, 47.
contraction in the, 124.
coats of muscular and elasticJ 24, 125.
HERMANN BOERHAAVE'S opinion of

three series of them, 157.
injection of, from lymphatic vessels,

179, 182, 184-5,

the old question of whether some
lymphatic vessels may not be con-
tinued from small arteries, 186.
Arm, lymphatic vessels of, 140-3.
Ascites, produced by a ligature on the

venacava, 174.
account of, 197, 198.

1:0.

Ass, viffi of the intestines of, 187.

gknneruli of the kidney of, 190.
Atmosphere, knowledge of in HEWSON 's
time, 11.

Atrophy of articular cartilage, 179.

Attenuation of the lymph not always con-
nected with slow coagulation of
the blood, 58. See Coagulable
Lymph, and Bufly Coat.

Asote, said to darken the blood, 8.

effect of on the coagulation of the
blood, 20. See Coagulation.

BABINOTON. Dr. B.G., on the three parts

of the blood, xlii.

his term liquor sauguinis in use before

MiiLLBR nitrated it from the red

corpuscles of the frog, xliii-iv.

on the constitution of the blood, 73.

on increase of fibrin in the blood in

inflammation, 2. See Fibrin.
on blood remaining fluid long after

death, 17.
on the coagulation of blood covered

with oil, 20. See Coagulation,
on the coagulation of hurt") blood, 34.
on the serum of buffy blood, 38.
on the specific gravity of fibrin, 74.
on white or fatly serum, 85, 86.
on the increase of oil in olives, 86.
BAILLIB, Dr., a lecturer on anatomy at

Windmill-street, xvi.

HAILLIK, Mr. HUNTER, autograph letter

by FRANKLIN in the possession of,

about Dr. HUNTER and HEWSOX,

xrii.

BAKER, Mr., his microscope used by

HEWSON, 214.

B ARRiNGTox, the Hon. DAINES, a mem-

her of the council which awarded

the Copley medal to HEWSON, xxiii.

BARRY, Dr. MARTIN, on the spontaneous

division of the red corpuscles of

the blood, 225. See Corpuscles.

referredto,on fibrils from blood-discs,

14. See Fibrin, and Corpuscles.
on the formation of tissues from

blood-corpuscles, 235.
BARTHOLIN, Taos., on the lacteals of a

fish in the year 1652, rxii, 151.
on the lymphatic system, 119, 120.
BARTHOLIN 'and RUDBSCC, discovery of

the lymphatic system by, 245.
Basaris, like the ursid* in the size of its

blood-corpuscles, 218.
Bats, torpid, state of the blood in, 52.
BAUER, Mr., on the corpuscles in fibrin,

xxviii. See Fibrin,
entertained the hypothesis that the
fibres of fibrin are formed of co-
lourless nuclei of the red corpuscles
of the blood, xli.

Bdellostoma, spleen wanting in, 273.
Bears, size of the blood-corpuscles of, 218.

GENERAL INDEX.

323

BECLARD, supported the hypothesis that
the fibrin is formed of colourless
nuclei of the red corpuscles of the
blood, xlii. See Fibrin. .
BECQUEREL, referred to, 2.
BEDFORD, Dr., on the blood-corpuscles

of monotremata, 218.
BELL, Sir CHARLES, a lecturer on anatomy

at Windmill-street, xvi.
BERDOE, Dr. MARMADUKE, on the cras-

samentum, xxix.
BERZELIUS, on the liquidity of the fibrin

in the circulating blood, xliii.
Bibliotheca Anatomica, Essays on the

blood in, xxix.

Bibulous properties of the tissues, 199.
BICHAT, on the lymphatic glands at dif-
ferent periods of life, 246.
BIDLOO, on the coagulation of the blood,

xxvii. See Coagulation,
called the red corpuscles globossc

vesiculsc, xxvii, 222.
Bile, transudation of, see Transudation.
Bilin, conjectured to be a product of
changes in the red corpuscles of
the blood, 236.
Birds, publication of HEWSON'S papers on

the lymphatic system in, xxi.
on the controversy as to the discovery

of parts of that system, xxii.
chyle of, 86, 87, 123, 146; chyme

of, 87.
fat of, supposed to be a new-formed

substance, 87.
on the discovery of the lymphatic

system in, 91, 121.
lacteals in, discovery of, 102.
description of the lymphatic system in,

144. See Lymphatic System,
lymphatics of, how to be demon-
strated, 146. See LymphaticVessels.
intestinal villi of, 189, 192. SeeVilli.
figure and size of the red and pale
blood-corpuscles of,218-19, 253-4.
short diameter of their red corpuscles
similar to the diameter of the cir-
cular corpuscles of mammals, 219.
in the entire class of, the law as to the
size of the corpuscles nearly the
same as in a single family of mam-
mals, 219. See Corpuscles,
red corpuscles of the splenic blood of,

nuclei seen in, 283.
shape of the nucleus of the blood-disc
and the lymph-corpuscle of com-
pared, 279. See Nucleus,
measurements of the corpuscles of
blood and lymph of, see Measure-
ments.
BiscHOFF,on the office of the thymus, 280.

Bite of mad dog, how to be treated, 202.
BLAINVILLE, DUCROTAY DE, declared that
the fibrils of fibrin are not com-
posed of globules, xliii.

on the contents of the red corpuscles

of the blood, 223.

BLAIR, Dr., note by on Dr. MONRO'S lec-
tures on lymphatics, 111.
Bleeding, see Bloodletting.
Blister, properties of the fluid of, 196, 199.
Blood, see Coagulation, Corpuscles, Co-
agulable Lymph, Fibrin, Buffy
Coat, Serum, &c.

on the separation of fibrin from
blood by whipping, xxviii, xxx,
xxxi. See Fibrin.

supposed thinning of,in inflammation,
xxxi, xxxv, xxxvii. See Buffy Coat
and Coagulable Lymph.

QUESNAY on the thinning of, in in-
flammation, xxxi; and on the in-
crease of the fibrin, and decrease
of the red corpuscles, xxxi, xxxii.

fluidity of, not caused by its heat,
xxxiii. See Heat.

LEEUWENHOEK'S doctrine of, taught
by the first Dr. MONRO, xxxiv, and
opposed by SENAC, xxxii, by the
second Dr. MONRO, xxxiv, and by
HEWSOJJ, xlvi.

paleness of, in the young embryo of
vertebrata, xliv-v, 222.

specific gravity of, in acute and
chronic diseases, 2.

references to writers on the propor-
tions of its parts in disease, 2.

colour of, effects of air, gases, salts,
and state of the red corpuscles and
of stagnation on, 7, 8, 9, 11, 66.

venous and arterial, colour of, 7-10.

venous, sometimes scarlet, 10.

kept fluid by salts, 11.

putrefaction of, said not to occur be-
fore coagulation, 12, 69.

on the state of the fibrin in, 14, 73.

fluid many hours after death, and
coagulating on exposure, 16, 17.

extravasated, remaining long fluid, 17.

polypi of, in the heart, 23, 24.

fibre of, 30. See Fibrin.

paces with which the red corpuscles
sink in, 34. See Buffy Coat.

slow coagulation of, when huffy, an
effect and not a cause of the sepa-
ration of the corpuscles, 34.

thinning of, in inflammation, 37.

of the horse, is regularly buffy, 40.

effects of cold on, 42. See Cold.

properties of, changed during its
evacuation, 42, 44, 45, 46, 47.

324

GENERAL INDEX.

Blood, buffy, of women far advanced in
pregnancy, 40, 44.

from different vessels, 44.

viscidity of, increased by cold, 50,
51, 52 ; and by faintness, 57.

thickened by cold, 64, 65, 72.

sometimes does not coagulate, 68.

of the spleen, clots in, 69.

brightening of by air, 71.

effects of neutral salts on, 71.

sometimes florid in the veins, 71.

properties of, recapitulation of the
chief facts on, 71.

its coagulation retarded by cold, 72 ;
but promoted by air, 20, 72.

properties of, affected by the action
of the vessels, 72, 76.

state of the fibrin in, 73. See Fibrin.

its properties affected by vascular
action, 65, 68, 70, 72, 74, 75, 76.

serum of, and the milk-like serum, 78.

fluid mixture of, with salts, at what
heat coagulated, 82.

circulation of, without a heart, 1 24-25.

transudation of, see Transudation.

absorption of, when injected into
serous sacs, 172.

white, said to have been seen in the
mesenteric veins, 173.

supposed to dissolve bone, 183-4.

on the figure and composition of the
red particles of, 211. See Cor-
puscles, and Measurements.

colourless in the amphioxus, 234.

of the spleen, properties of, 269.

of the spleen, on the coagulation of,
283, 289. See Coagulation.

coagulation of, see Coagulation.

buffy coat of, see Buffy Coat.
Blood-clot, see Crassamentum.
Blood-corpuscles, see Corpuscles.

development of, in the animal series,
212.

function of, 212.

of insects, 211, 288.
Bloodletting, use of small cups in, 45.

buffy coat appearing at different times
during, 42. See Buffy Coat.

properties of the blood changed dur-
ing, 42, 44, 45. See Blood.

not always necessary when there is a
buffy coat, 48, 56, 57.

increases the disposition to coagula-
tion in the blood and thickens it,
59. See Coagulation, and Coagu-
lable Lymph.

effect of the orifice and stream of
blood on its coagulation, 60) 65.

improper when there is an excess of
serum in the blood, 1.

Bloodletting, (continued.}

effects of, on coagulation and on the
buffy coat, see Coagulation, and
Buffy Coat.
Blood-vessels, effect of, in retarding the

coagulation of the blood, xxxviii.
their effect on the blood, 44-6, 48.
their action said to affect the coagula-
tion of the blood, 65, 68, 70.
their .effect on the properties of the

blood, 72, 74, 75.

when acting strongly, said to thin the
lymph and retard coagulation, 76.
on irritability in the coats of, 124.
BLUNDELL, Dr., on coagulation of blood

of dogs, sheep, and oxen, 24.
Boa, its blood-discs differ in shape from

those of the slow-worm, 312.
BOERHAAVE, HERMANN, on the fibrous

part of the blood, xxvii.
on the coagulation of the blood, xxix.
his opinion of three series of arte-
ries, 157.
on the supposed series of globules in

animal fluids, 182.
BOERHAAVE, KAUW, his experiments on

absorption, 176.
BONNET and LISTER, on animals frozen

and revived by thawing, 19.
BORDENAVE, entertained the hypothesis
that the buffy coat of the blood is
formed of the colourless part of the
red corpuscles, xxviii, xli, 2.
BORELLI, JOH. ALPH., on the coagulation

of the blood, xxvi.
neglect of his accurate observations

on the blood, xxxix.
BOSTOCK, Dr., on the effect of agitation

on coagulation of the blood, 15.
on white serum, 86. See Serum,
on the use of the microscope, 213.
referred to, on the serosity, 79.
BOUSSINGAULT, on the formation of fat in

animals, 87.

BOWMAN, Mr., referred to, on the Mal-

pighian bodies of the kidney, 190.

his researches on cells referred to,

170.
BOYD, Dr., his observations on the weight

of the thymus, 261-2.
on the size and weight of the spleen,

265.

on the weight and size of the lym-
phatic glands at different ages, 246.
BOYLE, the Hon. Robert, on the coagula-
tion of the blood, xxvi.
on the effect of heat, spirit of wine,

and sublimate, on serum, xxvi.
BOYLE and LOWER, on milk-like blood or
serum, 85. See Serum.

GENERAL INDEX.

325

Brain, fluid in the ventricles of, not merely

an exudation, 170.
experiments to try whether it has

lymphatics, 139.
of the cod-fish, supposed injection of

lymphatics in, 155.
Breast, vesicular roots of the milk-tubes,

191.

cancer of, the lymphatic glands af-
fected in, 201.
Bristol, in Pennsylvania, Mrs. HEWSON'S

death there, xxi.
BRODIE, Sir BENj.,a lecturer on anatomy

at Windmill-street, xvi.
on the effect of electricity on the -

irritability of muscle, 20, 21.
BROMEFIELD, Dr., referred to on white

serum, 83.
Bromley, visits of Miss STEVENSON to

Dr. HAWKESWORTH at, xx.
BROWN, Rev. Mr., master of the grammar-
school at Hexham, xiv.
Bruised parts, extravasated blood remain-
ing long fluid in, 70.
Bubo, venereal, glands in which it is

seated, 129.
BUCHANAN, Dr., on the state of the fibrin

in the circulating blood, 14, 32.
on fibrin and serum, 31.
on self-coagulation in mixtures of

varieties of serum, 31, 32.
on white or chylous serum, 85.
referred to on the fluid of blisters, 196.
BufFy blood, slow coagulation of, not a
cause but an effect of the separa-
tion of the fibrin and red corpuscles,
6, 34. See Buffy Coat,
proportion of fibrin in, QUESNAY,
GAUBIUS, HEY, BABINGTON,
GRAINGER," WHARTON JONES,
SIMON BORDENAVE, SYDENHAM,
referred to, 2.

excess of fibrin in, supposed to be

at the expense of the albumen, 38.

consistency of upper and lower part

of the crassamentum in, 73.
aggregation of the red corpuscles in,
34, 40-1, 221. See Buffy Coat,
and Corpuscles.
Buffy coat of the blood, MALPIGHI on the

structure of, xxvi.
COLLINS on, xxvii.
SYDENHAM on, xxvii.
QUESNAY on, xxvii-xxviii.
BORDENAVE on, xxviii, xli.
on the pale corpuscles in, xxviii.
HUXHAM on, xxix.
HALLER on, xxx.
MARHERR on, xxx.

SCHWENKE Oil, XXX.

Buffy coat of the blood, (continued.)
GABER on, xxx.
QUESNAY on the nature and causes

of, xxxi.
SENAC on, xxxii.
Dr. BUTT on, xxxiv.
Sir JOHN PRINGLE on, xxxiv.
GAUBIUS on, xxxv.
Dr. DAVIES on, xxxv.
Dr. GEORGE FORDYCE on, xxxvii-viii.
Mr. HUNTER on the formation of,

xliv, xlv.
aggregation of the corpuscles during

its formation, xlv, 40, 41, 221.
supposed to be formed at the expense

of the red corpuscles, xxxi-ii, 2.
supposed to be formed of coagulated

serum, xxxv, 30.
supposed to be caused by a change

in the serum, xxx, xxxv, 30.
specific gravity of, xxxv, 73.
consists of the coagulable lymph, 15,

30, 32, 33.

often confounded with the serum, 30.
experiment to show their difference,

31.
prevented from forming by stirring

the blood, 33.
not formed in some cases of slow

coagulation, 33, 37 ; nor in blood

drawn during syncope, 33.
state of the coagulable lymph when

the crust is to form, 34*.
state of the red corpuscles, 34, 40-1,

221, and their paces of sinking

during its formation, 34, 41.
slow coagulation not the cause but

an effect of its formation, 6, 34.
connexion of slow coagulation with,

33, 34, 35, 36, 55, 57, 73.
its connexion with a thinning of

the coagulable lymph, 37, 39-40,

58, 73. See Coagulable Lymph,
merely the coagulable lymph mixed

with serum, 73.
slow coagulation of blood about to

be buffy, 33-4, 73.
not a certain sign of inflammation, 40,

74.
absent when the blood trickles from

the vein, 60 ; but not always, 61.
whether produced by a ligature on

the arm, 65, 66, 67, 68.
regularly forms in horses' blood, 40.
in pregnant women, 40, 48.
appearing at different times in blood-
letting, 42.
diversities in, 41.
their pace of sinking thus curiously

accelerated, and vice versa, 41.

326

GENERAL INDEX.

Buffy coat of the blood, (continued.)

effect of saline medicines in inflam-
mation, 41.

sometimes partial, 45.

supposed to be formed quickly by
vascular action, 48.

red pellicle over, 49.

connexion of vascular action with,
55, 56, 61.

not a certain guide for bloodletting,
48, 56, 57.

formed by sinking of the red cor-
puscles, 57.

from slow coagulation, 57 ; but most
from thinning of the blood, 58,

texture of, at the top and bottom of
the clot, 59.

not a new-formed substance, 73, but
merely the coagulable lymph mixed
with serum, 73.

composed of oxydes of protein, 81.

slices of it kept scarcely changed for

months in saline solutions, 81.
Bullocks, jelly-like matter in the pericar-
dium of, after death, 198.
BURDACH, Professor, opposed the hypo-
thesis that the fibrils of fibrin are
composed of globules, xliii.

on the heat most favorable to the co-
agulation of the blood, 4.

on the formation of lymph-corpuscles

in the lymphatic vessels, 278.
Bust of HEWSON, xix.
Butcher-bird, blood-discs of, a narrow

ellipse, 313. See Corpuscles.
BUTT, Dr. J. M., on the coagulable lymph,
xxix.

on the effects of different tempera-
tures on coagulation of blood, 3.

on the serosity, xxxiv, 79.

his description of the blood-clot,
xxxiv.

on the buffy coat, the serum, and
serosity of the blood, xxxiv.

used the term coagulable lymph, xxxiv.

CALDWELL, Mrs., daughter of HEWSON,

xxi.

Calf, cavities in intestinal villi of, 187.
villi of intestines of, 187.
thymus of, its lymphatic vessels, 26 L
Caloric, effects of on the blood. See Heat.
Camelidae, shape, size, and structure of
the red corpuscles of the blood of,
218. See Corpuscles,
red corpuscles of the blood of agree in
structure with the corpuscles of
other mammals, 222.
red corpuscles of, manner in which
they aggregate, 228.

Camelidae, (continued.)

round shape of the corpuscles of the
lymph, thymus fluid, pus, and pale
corpuscles of the blood in, 253.
Cancer of the breast, the lymphatic glands
affected in, 201 ; also in cancer of
the lips, 202.

early excision of recommended, 203.
Capybara, size of the red corpuscles of the

blood of, 218. See Corpuscles.
Carbon, exhaled from the lungs, on the

source of, 235.

Carbonic acid, darkens the blood, 8.
effect of, on the red corpuscles, 9.
effect of, on coagulation of blood, 20.
Carnivora, size of the red corpuscles of the

blood of, 218. See Corpuscles.
CARPENTER, Dr., on buffy blood, 41.
on waste reorganizable matter, 88.
referred to, 181.
on the formation of fibrin, 235.
CARSON, Dr., on absorption by lympha-
tics, 180. See Absorption.
Cartilage, articular, hypertrophy and

atrophy of, 179.
Cassowary, size of the blood-corpuscles

of, 219. See Corpuscles.
Cat, villi of intestines of, 187.
Cats, size of the red blood-discs of, 218.
Caterpillar, blood-corpuscles and serum of

green, 234.

CAVENDISH, the Hon. HENRY, on the
council which awarded the Copley
medal to HEWSON, xxiii.
Cell, primitive, an organ of absorption, nu-
trition, growth, and secretion, 179.
Cell-nucleus of the present day, and HEW-
SON's central particle, xlviii.
Cells, fatty seeds or nucleoli of, 88.

agency of, in secretion, &c., 170, 179.

SCHWANN'S theory of, 14.

Central particles, see Nucleus, Corpuscles

of Lymph, Corpuscles of the Blood.

notice of HEWSON'S doctrine of, xlvii.

Central spot of the red corpuscles of the

blood, 216.
Cercoleptes, like the viverridae in the size

of its blood-discs, 218.
Chancre, excision of, recommended, 203.
Charcoal fire, fumes of, effect on the coa-
gulation of the blood, 68.
Chest, air in, HEWSON'S paper on, 291.
air escaping from, not always a proof

of a wound in the lungs, 299.
CHESTON, Mr., case of emphysema by, 222
Chick in ovo, has larger and rounder blood-
corpuscles than the hen, 233.
CHRISTISON, Dr., on white serum, 85.
on the effect of oxygen on the colour
of the blood, 8.

GENERAL INDEX.

327

Choroid plexus,trial for lymphatics in, 139.

Chyle, molecular base of, agreeing with

the milk-like matter on serum, 82.

of birds, said to be transparent and
colourless, 86, 123, 146.

of birds, suggestion, according to the
old view, that it may enter the cir-
culation by themesentericveins,87.

renderingserum white, 87. See Serum.

base of, composed of fatty particles, 88.

and lymph, course of, 123.

white in a crocodile, 147.

supposed originally to be absorbed
by veins, 172.

said to have been seen in the blood
of the mesenteric veins, 173.

of the seal, supposed to be absorbed
by veins, 179.

globules of, their chemical and other
characters, 253-4. See Corpuscles.

ruddy colour of in the horse, caused
by blood-corpuscles, 276, 277.

size of the corpuscles of, see Mea-
surements and Corpuscles.
Chyme of birds, 87 ; of the pheasant, 87.
CIGNA, on the colour of the blood-clot, 8.

on the effect of air on the colour of
the blood, 8. See Blood.

thought that the lungs serve to cool

the blood, 8.

Circulation of the blood, may go on with-
out a heart, 124, 125.
Coagulable lymph, 5. See Fibrin.

the term used by BUTT, xxix, xxxiv.

confounded with serum, xxix, xxx,
6,30.

PETIT on, xxx.

termed glaire,xxxi; and gluten, xxxvi.

the term used by HOULSTON and
GEORGE FORDYCE, xxxvii.

its tenuity said to be increased in
inflammation, see Inflammation.

its coagulation retarded by the blood-
vessels, and prevented by salt,
xxxviii.

notice of HEWSON'S inquiries con-
cerning, xxxviii-ix.

fluid when circulating, 14.

forms the buffy coat, 15, 30, 32-3, 73.

plugs up arteries, aneurisms, and
forms polypi, 15.

its share in diseases, 15.

is the self-coagulating principle of
the blood, 15.

effects of agitation on coagulation, 15.

separating in the veins, 22.

heat required to coagulate it, 26, 27,
78, 82.

experiments of separating it from the
red corpuscles, 31, 32.

Coagulable lymph, {continued.}

state of, in inflammation, 34.

properties of, changed during its eva-
cuation, 44.

one part remaining fluid when the
other has coagulated, 48-50.

sudden changes in its properties,
53, 54, 75, 76. See Blood.

properties of, altered by vascular
action ; and by struggles of a dying
animal, 57. See Blood.

may coagulate slowly without being
thinned, 58.

thickened by bloodletting, 59.

Dr. B. G. BABINGTON on, 73.

thinning of, in inflammation, 73.

its properties changed by the action
of the blood-vessels, 74, 75.

its disposition to coagulate, and its
consistency, connected with vas-
cular action, 76. See Coagulation.

thinning and retarded coagulation of,
from strong vascular action, 76.

how differing from serum, 78, 79, 80.

changes in the consistency of, in
disease, 161-2.

forming crusts, without ulceration, on
serousmembranes, xxxvii, 162,164.

changes of, in disease, 161-2, 164-5.

of blood, fluid of lymphatics and of
serous sacscomparedwith,161, 165.

of blood supposed to be converted
into pus, 165.

supposed sometimes to thin the blood,
169.

called mucago by HARVEY, 232.

supposed to be converted into the
envelopes of the blood-discs, 289.
See Lymph, Coagulation, and
Blood.

Coagulated lymph on serous membranes,
162. See Serous Membranes.

on membrane without idceration, 162.

in the pericardium of bullocks after
death, 198. See Pericardium, and
Fluid.

Coagulation of the blood, history of,
xxv-xlv.

ascribed to a fibrous matter, xxv ; to
a glutinous matter liquid in the
living body, xxvi, xxxv ; to a flat-
tening of the corpuscles, and the
mixture with them of a mucilage,
xxvii.

the self-coagulating principle well
understood in 1681, xxvi, xxviii;
and the discovery of it wrongly as-
cribed in 183 7 to Mr. HUNTER, xliv.

supposed to be due merely to the red
corpuscles, xxviii-ix, xxxix, xliii-iv.

328

GENERAL INDEX.

Coagulation of the blood, (continued.)

the serum described as spontaneously
coagulable, xxix, xxxix ; and con-
founded with the coagulable lymph,
xxx, 6, 30.

HALLER and MARHKRR on, xxix,
xxx, xxxix, xl.

QUESNAY on, xxxi, xxxix, xl.

correct views of PETIT on, xxx, xxxi,
xxxix, xl.

on the prevention of, by whipping,
xxxi-xxxiv.

SEN AC on, xxxii-xxxiv, xxxix, xl.

not caused by cold, xxxiii.

supposed to be prevented by its heat,
and by agitation, xxxiii.

SENAC on the effects of salts on,
xxxiii-iv ; and of air, xxxiii.

supposed to be promoted by cold and
rest, xxxv.

Dr. DAVIES on, xxxv-vi.

Dr. WILLIAM HUNTER on, xxvi.

Dr. G. FORDYCE on the retarding
effect of the blood-vessels on, and
on the prevention of by salt, xxxviii.

errors from a neglect of the accurate
observations of the old physiolo-
gists on, xxxix, xliv.

clear proofs, by HEWSON, that it is
alone dependent on the fibrin,
xli, xliii.

errors of Sir EVERARD HOME and
others, xli, xliii, disregarded in
Britain, where HEWSON'S views
continued, xlii.

Mr. HUNTER'S views on the con-
nexion of life with, xlv, 21 ; his ob-
servation that no heat is produced
by coagulation, xlv.

causes of, 1, 19-21.

effects of different temperatures on,
3-6; prevented by higher tempera-
tures, 4-6.

promoted by warmth, 3, 51 ; especially
at 98° and a little higher, 4, 5.
See Heat.

of blood and salt, 5.

of salt and liquor sanguinis diluted
with water, 6.

hastened by adding red corpuscles to
diluted liquor sanguinis and salt,
and to pure blood, 6.

different effects of saline solutions of
different strengths on, 13.

precedes its putrefaction, 12, 69.

retarded by mucilage, 13.

very slow when confined in veins, 16.

effects of air on, 8, 9, 18-21, 25, 61,
64, 72.

effects of salts on, 11, 12.

Coagulation of the blood, (continued.)
effect of agitation on, 15, 16.
effects of cold on, 17, 18, 20, 21,50,

51, 52, 61, 72. See Cold,
effects of freezing and of thawing on,

17-19, 21, 25,26.
effect of rest on, 16, 19, 20, 21,

25, 72.
effects of lightning or electricity on,

20; and of hunting, 21.
effects of air, of a vacuum, of nitro-
gen, of nitrous gas, of oxygen,

nitrous oxide, carbonic acid, and

of hydrocarbon on, 20.
effect of water on, 44.
effect of serum on, 44.
probably hastened by the fluid of the

lymphatics in the last flowing

blood, 44.
effect of red corpuscles on, 6,

34, 44.

effect of the action of the blood-
vessels on, 65, 68.
effects of struggles of a dying animal

on, 57, 76.
effect of suffocation, of drowning,

and of hanging on, 68, 69.
cause of its fluidity unknown, 20.
not caused by air, 19.
not caused by cold, 20, 21.
not caused by rest, 20, 21.
said to be an act of life, 21.
in hunted animals, 21.
in veins, 16, 21-23.
confined in living and dead parts, 23.
time required for, in different animals

and constitutions, 24, 25.
forming false conceptions or moles

in the uterus, 25.
in aneurisms, 25.
in amputations, 25.
prevented by what heat in diluted

salt and blood, 27. See Heat,
in inflammation, 33-36, 53, 55.
retarded by the separation of the cor-
puscles, 6, 34, 44.
slow in the heart after death, 36, 37 ;

and yet may be without a buffy

coat, 37.

hastened by faintness, 46, 47, 57.
from slaughtered sheep, 44, 46, 47.
in hybernating animals, 52.
slower in inflammation, 53, 55.
hastened by weakness and diminished

vascular action, 53, 54.
retarded by strong vascular action, 55,

76.
may be retarded without thinning of

the lymph, 58. See Buffy Coat,
later in plethora, 59.

GENERAL INDEX.

329

Coagulation of the blood, (continued.)
pellicle on when coagulation begins,

59, 63, 73.

sometimes does not occur, 68, 69.
causes said to prevent it, 68.
said to be altered by the blood-ves-
sels, 53-5, 70, 76.

remaining long fluid in tumours, 70.
retarded by cold, 72.
promoted by air, 72.
slow in the body after death, 72.
retarded by contact with the living

tissues, 72.
time required for, 161 ; hastened in

weak animals, 161.
not taking place in frogs kept long

without food, 161.

Coagulation, of serum and fibrin, 78, 79.
by heat of a mixture of blood and

salt, 6, 82.
of lymph which was fluid twenty -four

hours after death, 161.
of the lymph, time required for, 161.
of the fluid of a blister, 196.
in a mixture of varieties of serum, 21,

31, 158, 196, 235.
COCKSON, Mr., 66.
Cod, liver of, increase of oil in, after

death, 86.

Cod and whiting, lymphatic system of, 154.
Coins, red corpuscles of the blood laid to-
gether like, xlvi, 221, 228; re-
ferences to engravings of the
rolls, 221 ; the oval corpuscles not
running together so regularly, 228.
Cold, effects of, on the coagulation of the
blood, xxxiii, xxxv, 17, 18, 20, 21,
50-52, 61, 72.

effects of, on the blood, 42, 61, 64.
thickens the blood, 64, 65, 72.
retards the coagulation of the blood,

72. See Heat.

COLLINS, Dr. S., on the coagulation of the
blood, on polypi of the heart, and
on the structure of the crassamen-
tum and buffy coat, xxvi, xxvii.
Colon, villous coat of, 188.
Colour of the blood, effect of air, oxygen,
and some gases on, 8. See Blood.
Colour, florid, of the surface of the cras-
samentum, caused by ah>71 ; and
of the blood in passing through
the lungs, 71. See Blood, &c.
Consumption, pulmonary, seat of the tu-
bercle in, 138.
Contractility of muscles, causes said to

destroy it, 20, 21.

Contraction of the blood-clot, diminished
by aqueous saline solutions, but not
so by mucilaginous ones, 13.

COOK, JOHN, on the coagulation of the

blood, xxviii, xxix.
COOPER, Sir A., on the effects of air on the

coagulation of the blood, 20.
on coagulation of blood in living and

dead veins, 23.

on the structure of the breast, 191.
on the structure and use of the thy-

mus, 257, 261.
on the lymphatic ducts of the thy-

mus, 281.
COPLAND, Dr., on the formation of the

buffy coat of the blood, 235.
COPLEY, Sir GODFREY, award of his medal

to HEWSON, xxiii, xxiv, 91.
CORNISH, Mr., on the blood of torpid

bats, 52.

Corpora globosa of the kidney, 190.
Corpuscles, red, of the blood, adding them

to blood, or to diluted blood and

salt, promotes coagulation, 6.
first publication of HEWSON'S paper

on, xxiv.

discovered by Malpighi, xxvi.
called globosae vesiculae by BIDLOO,

xxvii, 222.
supposed to be converted into fibrin,

xxvii, xxviii, 2, 31, 235-6.
supposed to be the self-coagulating

principle of the blood, xxviii, xxix.
supposed change of, into the buffy

coat, xxxi, xxxii.
notice of HEWSON'S experiments on

their sinking in the blood and in

serum, xxxi, xxxviii.
specific gravity of, xxxv, 73^4.
the fibrin separated from them, and

their integrity preserved by salts,

xli, xliii.
hypothesis that the fibrin is formed

of their. colourless part or nuclei,

xli-xliii.
the coagulation of the blood attributed

to them, xxvii, xxix, xliii.
differ from the globules of the tissues,

xliii,
wanting in the very young embryo of

vertebrata, xliv-v.

Mr. HUNTER observed their aggre-
gation during the formation of the

buffy coat, xlv.
their flat figure, xlvi.
seen laid together like coins, xlvi, 221.
effect of water on, xlvi, 215, 221-4,

230, 274, 288.

effect of saline matter on, xlvi, 274-5.
nucleus of, in lower vertebrata^ xlvi.
differ in the same blood, xlvi, 232-3.
larger in the embryo than in the

adult, xlvi.

330

GENERAL INDEX.

Corpuscles, red, of the blood, (continued.)

split into pieces to the centre, and
each portion retains its red colour,
xlvi, 226.

relation of lymph-corpuscles to, xlvii,
254, 277.

found in the lymph of the spleen and
of other parts of the lymphatic
system, xlvii ; their red envelopes
supposed to be formed there, 273,
282-3.

their density or cohesion said by
SENAC to affect the colour of the
blood, 8.

effects of salts, sugar, oxygen, and
water, on the size of, 9.

the colour of the blood affected by
changes in them, 9, 10.

not forming fibrin in mixtures of se-
rum, 32. See Fibrin.

their state in buffy blood, 34, 40, 41.

their paces of sinking in buffy blood,
34, 38. See Buffy Coat of the Blood.

their separation from the liquor san-
guinis retards its coagulation, 34.

sink faster in blood than in serum,
37, 40.

specific gravity of, xxxv, 73 ; and in
buffy blood, 38, 39.

their running into rolls, 41, 221,
228.

of buffy blood, their aggregation,
34, 40, 41, 221, 229, 231; and
effect of saline medicines on, 41.

their paces of sinking, and how af-
fected by their aggregation and by
the consistency of the blood, 40-1.

their sinking in the serum, 41.

hasten the coagulation of the blood,
44.

sinking of, produce the buffy coat, 57.

their rate of sinking in a fluid may
give a wrong idea of its viscidity
or density, 58.

their clumping in the blood in inflam-
mation prevented by neutral salts,
41, 71.

their sinking in the formation of the
buffy coat attributed to a thinning
of the lymph, 73.

found generally in the vertebrata, 211.

on the figure and composition of, 21 1.

development of in the animal series,
212.

thickness of the corpuscle in relation
to its breadth, 215, 216.

their flat figure, xlvi, 214, 219-21,
227-9, 231, 274, 287-8.

described as flat as a guinea, or shil-
ling, 215, 287-8.

Corpuscles, red of the blood, (continued.}

how to dilute the blood, to examine
them, 215, 219-20.

membranous and colourless base o
the corpuscle, 215, 223.

depression in, 216.

central spot, 216, 220, 221, 224, 226,
287.

dimensions of the corpuscles of man,
216 ; and of other vertebrata,
217-19. See Measurements.

nucleus of the corpuscles of oviparous
vertebrata, 216,222, 224, 253,288 ;
no such nucleus in mammals, 222,
except in very young embryos, 222 ;
figure of the red corpuscles in such
embryos, 216.

their size and form in different adult
animals, 217-19; and in man,
216.

measurements of, see Measurements.

no relation in different orders of mam-
mals as to the size of the animal and
that of its corpuscles, 218, though
there is in a single family, 218, and
in the entire class of birds the law
.for the size of the corpuscles the
same as in a single family of mam-
mals, 219.

action of a saline solution on, 41, 220,

223, 229, 231-2, 274-5, 288.

the corpuscles are solid, and not oily,
or more inflammable than the rest
of the blood, 220, 227.

supposed hole in the corpuscles, 221,

224, 225, 287.

laid together like coins, 221, 228.
viscidity of, 221.
vesicles of, 221-4, 225, 226.
puckering or shrinking of the cor-
puscles of mammals, 223, 225.
effect of dilute muriatic acid on, 223.
deviations from the regular shape of,

223, 225, 229.
contents of, 223.
effects of incipient putrefaction on,

225.

shape of the nucleus in birds, 225.
effect of water on the nucleus, 225,

and of acetic acid, 225.
molecules attached to, and detached

from, the red corpuscles, 225.
spontaneous division of the corpuscles,

xlvi, 225, 226.
fissures through, 226.
not breaking into any regular number

of pieces nor into pale globules,226.
nucleus seen to escape from a fissure

in the envelope, 226.
mode of showing the nucleus, 232.

GENERAL INDEX.

331

Corpuscles, red, of the blood, (continued.")
each portion of the divided vesicle

red, xlvi, 226.
run into rolls in mammalia, 228, but

not so regularly in the Camelida3

and in the lower vertebrata, 228.
supposed not to alter their shape,

when circulating in a narrow vessel

228, but they do, being very pliant
and elastic, 228-9.

the forms which they assume, 229.
their flatness preserved by the salts

of the serum, 229, 231.
shrivelled by strong saline solutions,

229, 232.

effects of weak solutions and of urine
on, 229-31 ; the salt keeps the
corpuscles from running together,
229, 231 ; and alters their shape
variously, 229-32.

effects of various salts on, 230-31.

effects of acids and alkalies, 230-31.

effect of spirits of wine, 231.

differ in size and in chemical pro-
perties in the same animal, 232-3,
236.

differ in size and form at different
periods of life, 233.

their size and shape in fishes, ten-
derness of the envelope, and shape
of the nucleus, 234.

wanting in the amphioxus, 234, 273.

general diffusion of in the animal king-
dom, 209, 211, 235.

supposed to convert albumen into
fibrin, 235.

supposed to be formed by certain
organs, 236, 273, 275.

supposed uses of, 212, 235-6.

differ in chemical properties from
pale cells, 235, 254.

supposed separation of the envelope
during the formation of fibrin,
xli, 235-6.

alter in shape or size if they come
with difficulty from a minute prick,
236.

of mammals larger when quickly dried
than when kept moist, 236-7.

of birds and reptiles, smaller in the
dry state than when wet, 237.

shape of in birds and reptiles, 218-19,
312.

on the formation of, from the pale
globules of the blood, 254.

in the splenic lymph, 273.

on the manner in which they are
formed, 274.

vesicle and nucleus of, 274 ; and ad-
hesion between them, 275.

Corpuscles, red, of the blood, (continued.}

the nucleus temporary in mammals and

permanent in lowervertebrata, 275.

differ in figure and size in different

animals, 275, 279-19.
vesicles of, supposed to have nuclei in
all animals, 275.

the corpuscles supposed to be formed
by the lymphatic system and its
appendages, 275.

in the lymphatics, 276, 277 ; and in
the thoracic duct, 276 ; but not so
perfect as those in the blood, 277.

supposed formation of, from chyle or
lymph-globules, xlvii, 254, 277.

red envelope of, formed in the lym-
phatics emerging from a lymphatic
gland, 277 ; and in the spleen,
282-6.

lymphatic vessels and glands may
form the red part of the blood ,277.

formed in lymphatic vessels indepen-
dently of the glands, 278, 284.

nuclei in those of the spleen of a
bird, 283.

from the heart and spleen compared,
283.

envelope of, see Envelope.

HEWSON'S letter to Dr. HAYGARTH
concerning, 287.

in birds, the shape of the nuclei com-
pared with that of the lymph- cor-
puscles, 253, 279.

nuclei of, formed in the thymus and
lymphatic glands, 289.

figure of a narrower ellipse in the
slow-worm than in the snake or
adder, and examples of a difference
of shape in the corpuscles of other
nearly allied animals, 312.
Corpuscles in the fluid of the lymphatic
glands described, 253.

compared to the nuclei of blood-discs,
253. See Nucleus.

do not vary in size and shape like
those discs in different animals,
and differ in figure from the nucleus
in the blood-disc of birds, 253.

their size in the musk-deer, 253.

of the usual round shape in the ca-
melidffi and in birds, 253.

smaller than the pale globules of the
blood, 253.

insoluble in water, 253.

their structure and chemical charac-
ters, 253-4.

differ in chemical properties from the
red corpuscles of the blood, 254.

considered as nuclei or immature
cells, 254.

332

GENERAL INDEX.

Corpuscles of lymph, (continued.)

larger in small ruminants than the
red corpuscles of the blood, 254.

described as central particles, 276,
281.

sizes of, see Measurements.
Corpuscle of chyle or lymph, of its tran-
sition into the red corpuscle of
the blood, xlvii, 254,277.
Corpuscles of lymph, have the same charac-
ters as the corpuscles of the thymus
fluid, 254, 259.

of the lymph of oviparous vertebrata
and of mammalia compared, 212.

formed in the lymphatic vessels inde-
pendently of the glands, 278.

their size and shape in different ani-
mals, 278-9. See Measurements.

formed in the lymphatic glands,
and independently of them, 278.

their shape in birds compared with
that of the nucleus of theblood-disc,
253,279.

their similar shape in animals with
differently-shaped blood-discs, 279.

office of the thymus in forming them,
279-80, 286, 289.

may be constantly in astate of dissolu-
tion and renovation, 281.

supposedto be converted in the spleen
into red corpuscles of the blood,
282-3.

considered as nuclei or immature
cells, 281.

may grow into the more perfect pale
cell of the blood, 282.

seen in the blood by Hewson, 282.

formed in the thymus and lymphatic
glands, 286, 289.

formed in the lymphatic vessels, 289.
Corpuscles of the blood of insects, 211,288.

colour of in insects, 233, 234.

of the lobster described, 234 ; of the
shrimp, 234 ; of the grasshopper,
234 ; of the monoculus, 234-5 ; of a
caterpillar, 234.

Corpuscles, pale, of the blood, their abun-
dance in the blood of very young
embryos of vertebrata, 222.

seen by HEWSON, xlvi-vii, 282.

no other in the amphioxus, 234, 273.

differ in chemical properties from the
red corpuscles, 235, 254.

supposed to elaborate the fibrin, 235.
' sizes of, see Measurements.

of the common round shape in the
Camelidae, 253 ; and in birds and
reptiles, 253.

nuclei of, 253.

compared withlymph-corpuscles,253.

Corpuscles, pale, of the blood, (continued.)

on red corpuscles formed from, xlvii,
254.

are the prevailing ones in the am-
phioxus, 273.

contradictory evidence as to the
existence of, in splenic blood, 283 ;
seen in it, and compared with pale
corpuscles in other blood, 283.
Corpuscles of the thymus fluid, have the
same characters as the lymph-cor-
puscles, 259.

on the question of their passage into
the lymphatics, 280-1.

may be constantly in a state of disso-
lution and renovation, 281.

more abundant than in the fluid of
the lymphatic glands, 281.

considered, like lymph-corpuscles, as
nuclei or immature cells, 254, 281.

supposed to be converted in the
spleen into red corpuscles of the
blood, 282-3.

size of, see Measurements.
COSTE, M., on the pale blood of the young

embryo of vertebrata, 222.
Covent Garden, HEWSON attends Dr.

HUNTER'S lectures there, xv.
COWPER, WILLIAM, considered the blood
as consisting only of the serous
and globular parts, xxvii.

on the coagulation of the blood, 28, 29.

on the pliancy of the blood-discs
when circulating in a narrow chan-
nel, 228-9.

Crassamentum, constituents and struc-
ture of, xxv-xxix.

SEN AC on the parts of, xxxii.

SENAC'S description of, xxxiii.

the parts of described, xxxiii, xxxiv,
xxxv.

the fibrin obtained from by washing,
xxvi, xxviii, xxx, xxxii, xxxv.

specific gravity of, xxxv, 73.

proportion of in different cases, in-
creased in size by adding weak sa-
line solutions to fluid blood, 1.

separation of serum from, 1.

colour of, 1 , 8.

constituents of, 5, 6.

floridness of top of, 6, 71.

darkness of bottom of, 7.

supposed sinking of corpuscles in, 7.

consistency of upper and lower part
of in buffy blood, 7.

effects of water, sugar, and salt, on
the colour of, 8.

contraction of, diminished by aqueous
but not by mucilaginous saline so-
lutions, 13.

GENERAL INDEX.

333

Crassamentum, (continued.)

a sac in, containing coagulable fluid,

49.
florid colour of surface of, owing to

air, 71.
and serum, heat most favorable to

their separation, 71.
red, a small portion of, in the thoracic

duct, 277.
CRAWFORD, Dr., on the colour of the blood,

10.

Crocodile, chyle of, white, 147.
CRUICKSH ANK, Mr., a lecturer on anatomy

at Windmill street, xvi.
on the supposed mouths of the lac-
teals in the villi, 181.
on the structure of the breast, 191.
on the size of the lymphatic glands

at different ages, 246.
Cruor, drained of serum, specific gravity

of, 73. See Crassamentum.
Crust, inflammatory or pleuritic, 30. See

Buffy Coat of the Blood.
CULLEN, Dr., cited on blood not coagu-
lable, 69 ; referred to on the sero-
sity, 79.
Curd, of fresh salmon, converted into oily

matter, 86.

CUVIER, on fishes in hot springs, 27.
Cyclostomatous fishes, blood-corpuscles of,
234 ; the spleen wanting in some,
283.

DANGER, M., on absorption of poison by

branches of the portal vein, 180.
DAVIES, Dr. RICHARD, on the buffy coat,
crassamen, and coagulation of the
blood, xxxv.

on the proportion of serum and clot
of the blood, xxxv.

considered the gluten thinned in in-
flammation, xxxv.

on the specific gravity of different
parts of the blood, xxxv-vi.

supposed that he first discovered the
gluten or self-coagulating matter,
xxxvi.

his clear demonstration of the three
parts of the blood, xl, xli.

date of his researches, notice of his
tables of sp. gravities, and of his
epistle to STEPHEN HALES, xl.

his distinction of the parts of the
blood adopted by HEWSON, FOR-
DYCE, and the HUNTERS, xli-ii.

on the contraction of the fibrin press-
ing out the serum from the blood-
clot, 1.

on the buffy coat of the blood, xxxv,
60.

DAVY, Dr. JOHN, his historical notices on
the coagulation of the blood, xxv.
on the three parts of the blood, and
on the liquid, viscid, and solid
states of fibrin, xlii.
on the specific gravity of blood first
and last flowing from slaughtered
animals, and in acute and chronic
diseases, 2.

on the effects of warmth on coagula-
tion of the blood, 4.

on the colour of the blood, 8, 9, 10.

on the effects of salts and other mat-
ters on coagulation of blood, 12.

on the effect of agitation on the coa-
gulation of the blood, 16.

on blood remaining fluid many hours
after death, 17.

on effect of cold on coagulation, 18.

on the effects of freezing and of thaw-
ing the blood on its coagulation, 19.

on leeches reviving after having been
frozen, 19.

on the effects of air, of a vacuum, of
carbonic acid, and of oxygen, on
the coagulation of blood, 20.

on the effect of lightning on the
coagulation of blood and contrac-
tility of muscle, 20.

on broken blood-clot in the heart, 24.

on some cases of high animal heat, 27.

on buffy blood, 34.

on the serum of buffy blood, 38.

on the coagulation of blood from
slaughtered animals, 44.

on the blood of torpid animals, 53.

on cases in which the blood did not
coagulate, 68.

on the specific gravity of different
parts of the blood, 73.

on the specific gravity of serum, 78.

on the effect of rennet on serum, 80.

on the increase of oil in the liver of
the cod-fish after keeping, 86.

suggests, according to the old opi
nion, that the chyle of birds may
enter the circulation by the mesen-
teric veins, 87.

on the chyme of the pheasant, 87.

analysis of nucleoli of cells, 88.

on the coagulation of the fluid of
lymphatic vessels, 159.

on transudation through membranes,
169.

ontheblood-corpusclesoftheechidna,
218.

on the blood-corpuscles of a hum-
ming-bird, 219.

on the viscidity of the red corpuscles
of the blood, 221.

on a red clot in the thoracic duct, 277.

334

GENERAL INDEX.

DAVY, Sir HUMPHREY, on the effect of

gases on coagulation of blood, 20.
on the curd of the salmon, 86.
Dead and living parts, coagulation of

blood confined in, 23.
DE HAEN, confounded coagulable lymph

with serum, xxx.

DELAFOND,on the blood of the horse, 40.
DELLA TORRE, on the shape of the red

corpuscles of the blood, 211.
his glasses, 214, 225.
on the centre of the blood-disc, 216.
supposed that the red corpuscles of

the blood are perforated, 221.
his figures of the division of the
red corpuscles of the blood, 226 ;
and of the rolls of the corpuscles,
221.

DELPECHE, M., on the pale blood of the
young embryo of vertebrata, 222.
DENIS, M., incorrectly declares that he dis-
covered the liquidity of the fibrin in
the circulating blood, xliii.
on the coagulation of fibrin after it

has been dried, 21.
on the buffy coat of the blood, 33.
on fibrin and albumen, 81.
on fibrin and serum, 81.
Dictionnaire Raisonne d' Anatomic, xxx.
DIONIS, on the use of the thymus, 261.
Dog, coagulation of the blood of, 24, 27 ;

villi of the intestines of, 187.
Dogs, size of the blood-discs of, 218.
DONNE, on the use of the spleen, 273.
DOWLER, Mr., on the fibres of fibrin as
distinguishing it from albumen,
xlv.
DRAKE, on the coagulation of the blood,

xxix.
Dropsy, proportion of serum in the blood

increased in, 1.

properties of the fluid of, 157, 160.
produced by a ligature on the vena
cava, 1 74 ; and on the jugulars,
175.

account of, 196-204. '
Drowning, effect of, on the coagulation
of the blood, 68, 69, and on the
rigidity of muscle, 69.
state of the blood in the splenic vein

of kittens killed by, 269.
DRUMMOND, Dr., 66.
Duct, thoracic, see Thoracic Duct.
Ductus aquosi, 123, 157.
DUMAS, entertained the hypothesis that
the fibres of fibrin are formed of
colourless nuclei of the red cor-
puscles of the blood, xlii.
on the formation of fat in animals,
87.

DUTROCHET, supported the hypothesis
that the fibres of fibrin are formed
of colourless nuclei of the red cor-
puscles of the blood, xlii.

DUVERNOI, observed the vesicular roots
of the milk-ducts, 191.

Ecchymoses, blood remaining long fluid

in, 70.

Echidna, on the blood-discs of, 218.
Edinburgh, HEWSON studied and attended
Dr. MONRO'S lectures at,xiv,xv,92.
LEEUWENHOEK'S doctrine on the
blood taught at, by the first Dr.
MONRO, and opposed by the se-
cond, xxxiv.

EDWARDS, Dr. MILNE, supported the hy-
pothesis that the fibres of fibrin are
formed of colourless nuclei of the
red corpuscles of the blood, xlii.
states the belief on the Continent,
that the coagulation of the blood is
produced by thered corpuscles, xliii.
Electricity, effect of, on coagulation of
blood and irritability of muscle, 20, 21.
Elephant, large size of its blood-discs, 217.
Embryo, young, of vertebrata, discovery of
the paleness of the blood in, xliv-v.
red corpuscles of the blood of, larger
than those of the adult, xlvi, 233.
of a fowl, red corpuscles of the blood
larger and rounder than those of
the mother, 233 ; and so in the
viper, 233.
of mammals, blood - corpuscles of,

larger than after birth, 233.
abundance of pale corpuscles in the

blood of, 222.

paleness of the blood of, xliv-v, 222.
nuclei in the red corpuscles of, 222.
Emphysema, HEWSON'S account of his
paper on, in answer to Dr. MONRO,
92.

remarks on, 291.
experiments concerning, 295.
cases from wounds of the lungs, 297.
from an abscess in the lungs, 301.
best place for performing the para-

centesis thoracis for, 301.
Empyema, matter of, instance of its co-
agulating spontaneously, 16.
Envelope of the red corpuscles of the
blood, nucleus within the, like a
pea in a bladder, 274.
action of water on the envelope, 274 ;

and of a neutral salt, 274-5.
adhesion between the envelope and

nucleus, 275.

formed in lymphatics emerging from
a lymphatic gland, 277.

GENERAL INDEX.

335

Envelope of the redcorpuscles,(con#m«ed.)
experiments on, 221-4.
in birds, differs in shape from the

nucleus, 225.
formation of, 225.
fissures through, 226; and nucleus

seen to escape from, 226.
formed in the lymphatic vessels, 284.
supposed to be formed in the spleen,
282-6, 289, and of coagulable
lymph, 289. See Corpuscles, red,
of the Blood.

EUSTACE, Mr., his case of white serum, 83:
EUSTACHIUS, on the thoracic duct, 120.
EVANS, Mr., on the coagulation of splenic

blood, 269.
Excision of recent chancres and of cancers

recommended, 203.

Extravasated blood, instances of its re-
maining long fluid, 17, 70.
Experiments to determine whether the
brain has lymphatics, 139.

Faintness, favorable in haemorrhages, 46.

hastens coagulation of blood, 46, 47.

increases the viscidity of the blood,
and its disposition to coagulate, 57.
FALCONAR, MAGNUS, his publication of
the third part of HEWSON'S Inqui-
ries, xlvi.

his perception of the importance
of HEWSON'S doctrine of central
particles, xlvii-viii; and his gene-
rous fidelity to HEWSON, xlviii.

supposed he had injected lymphatics
in the brain of the cod-fish, 155.

had the intention of publishing on
the structure of glands, 251.

synopsis of his lectures, 251.

sale-catalogue of his and HEWSON'S
museum, 251.

saw the pale corpuscles in the blood,

282.

False membranes, Dr. HUNTER'S descrip-
tion of, xxxvii; and HEWSON'S,
162.
Fat, nutritious qualities of, 87.

formation of, in animals, 87.

in birds, supposed to be a new-formed
substance, 87 ; more abundant in
their chyme than in their food, 87.

use of, in respiration, 88.

supposed to bereabsorbedfor nourish-
ment, 88.

reabsorption of, supposed to cause a
plethora, 89.

importance of, for cell-seeds, in nu-
trition, 88, 280.

supposed formation of, from albumen,
86.

Fat, (continued.)

absorption of, supposed to cause milk-
like serum, 86, 87, 88, 89.

conversion of, into a protein-com-
pound, 88. See Oil.
Ferae, on the size of the red corpuscles

of the blood of, 219.

Fibre of the blood, xxxiv, 30. See Fibrin.

Fibrin of the blood, fibres of, xxv, xxvi,

xli , xlv ; microscopic examination

of them, xxvi, xxvii, xxviii, xxxii,

xli, xliii, xlv, 14, 31, 235.

effect on coagulation of removing it,
xxv, xxxi-v.

supposed to be formed of coagulated
serum, xxvi, xxix, xxx, xxxix.

liquid in the circulating blood, xxvi,
xxx, xxxv, xlii, xliii, 14.

called gluten, xxvi, xxxv, xxxvi, 5.

its fibres forming a network and
membrane, xxvi,xxvii, xxviii, xxxii,
xxxv, xlv, 14, 31.

the fibres tough and tensile, xxvii. xlv.

termed mucilage, xxvii, 232.

supposed conversion into, of the red
corpuscles, xxvii, xxviii.

obtained from the blood by whipping,
xxviii,xxx, xxxi, xxxii, xxxiii,xxxiv,
xxxv ; and from the clot by wash-
ing it, xxvi, xxviii, xxx, xxxii,
xxxv.

cells or organic germs in, when first
observed, xxviii.

confounded with serum, xxix, xxx,
xxxv, xxxix, 6, 30.

called the lymph or lymphatic part
of the blood by PETIT, xxx.

termed glaire, xxxi.

called coagulated lymph by SENAC,
xxxii, xxxiv ; and coagulable lymph
by BUTT, xxix, xxxiv, and by
HOULSTON and G. FORDYCE,
xxxvii.

QUESNAY and Mr. HEY on the ex-
cess of, at the expense of the red
corpuscles, in the blood in inflam-
mation, xxxi, xxini.

GAUBIUS on the excess of, in buffy
blood, xxxv.

clear knowledge of, by DA VIES, xxxv,
xl, xli.

called gluten, and said not to be
fibrous, by Dr.- HUNTER, xxxvi.

on the properties of, by Dr. GEORGE
FORDYCE, xxxvii-viii.

neglect of the old observations on,
xxxix, Ixiv.

clear proofs by HEWSON that it is
the self-coagulating principle of the
blood, xli, xliii,

336

GENERAL INDEX.

Fibrin, (continued.)

kept liquid by HEWSON and MULLER
by salts, in order to separate it
from the red corpuscles, xli, xliii.

supposed to be formed of the colour-
less matter or nuclei of the red
corpuscles, xli-xlii, but the accu-
rate conclusions of HEWSON ge-
nerally remained current in Britain,
xlii-xliv.

coagulation of supposed to produce
heat, xlii, but erroneously, as
proved by Mr. HUNTER, xlv.

its liquid, viscid, and solid states, xlii.

the term liquor sanguiuis in use be-
fore MULLER filtrated it from the
red corpuscles of the frog, xlii-iii.

long known as the coagulable prin-
ciple of the blood, though the dis-
covery of that principle is ascribed
to Mr. HUNTER, xliv; his researches
on the organization of, xlv.

distinguished by its fibres from albu-
men, xlv.

motions described in the fibrils of,
xlv.

when the term was introduced, xlv-vi.

fibrils of, their formation, opposed
to the cell-theory, 14.

change in fibrin after keeping, 15.

coagulation of after it has been
dried, 21.

masses of, called polypi, 23, 24.

softening of, a common disease, 24.

and albumen, xlv ; probably isomerical
substances, 30 ; but said to diifer in
their elements, 31.

a salino-alkaline solution of, said to
form liquid albumen, 31.

fibrils of in the clot form a mixture
of two kinds of serum, 31.

experiments in which it is separated
from the red corpuscles, 31, 32.

forms the buffy coat, 33.

state of in the circulating blood, 14,
32, 73.

supposed to be formed at the ex-
pense of the albumen, 38.

and serum, coagulation of, 78, 79.

its properties modified some time
after its coagulation, 81.

action of oxygen on, 81.

of arterial and venous blood, 81.

and serum, M.Denis' view of, 31, 81.

supposed conversion of albumen into
by the blood-discs, 235.

supposed to be elaborated by the
pale corpuscles of the blood, 235.

formed without the immediate agency
of the red corpuscles in the lymph-

Fibrin, (continued.)

atic vessels and lacteals, and in the
blood of invertebrata, 235 ; and
without either red or pale cor-
puscles in mixtures of serum, 235.

supposed to be formed of the central
part of the red corpuscles, 235.
See Coagulable Lymph, Buffy Coat,
and Liquor Sanguinis.
Fibrinous clots, softening of, 24.
FIELD, Mr., and Mr. HENDY, 63, 66, 67.
Filaria capsularia, frozen and revived by

thawing, 19.
Ferguson, the astronomer, signs HEWSON'S

certificate for the Royal Society, xvi.
Fishes, the lacteals observed in by T.
BARTHOLIN, xxii.

reading of HEWSON'S papers on the
lymphatic system in, xxiii.

heat cannot be the cause of the
fluidity of their blood in winter,
xxxiii.

in hot springs, 27.

increase of oil in after death, 86.

on the discovery of the lymphatic
system in, 91.

lymphatics of, 121.

and turtle, method of discovering
the lymphatics in, 151.

villi intestinorum of, 189, 192.

size and shape of the blood-discs
of 234 ; the envelopes very tender,
234 ; the shape of the nuclei, 234.

the spleen wanting in some of the
cyclostomes, 273, 283.

sizes of the blood-corpuscles of, see

Measurements.
Fissures in the red corpuscles of the blood,

226. See Corpuscles.
Flanders, HEWSON'S visit to, xvi.
FLANDRIN, on absorption of poison by

branches of the portal vein, 180.
Fluid, of serous sacs, LOWER on the coagu-
lation of by heat, xxvi.

of the lymphatic vessels, 123, 196-8.

of the serous cavities, supposed to be
mere water, 157; properties of, 158 -
161 ; coagulation of at the heat of
the air when mixed with serum of
blood, 21, 31, 158, 196, 235.

of the lymphatic vessels and serous
sacs compared to coagulable lymph
of blood, 165.

of lymphatic vessels and of serous sacs
compared, 185.

in the ventricles of brain not merely
an exudation, 170.

animal, supposed series of globules
in, 182.

in dropsies, nature of, 196-8.

GENERAL INDEX.

337

Fluid, (continued.}

of a hydrocele, its specific gravity and
coagulation by heat, 28, and at
the heat of the air, 32.

of a blister, 196, 199.

in rheumatic tumours, 198.

in the pericardium of bullocks, 198.

in the pericardium of the human sub-
ject, 158.

in the peritoneum of the tortoise, 158.

coagulating spontaneously, from a
wound of the lymphatics, 198.

of the lymphatic glands, 251, 252;
corpuscles of described, 253-4.

in the lymphatic vessels of the thy-
mus, 258 ; its white colour, 258-9 ;
microscopical examination of, 259 ;
the corpuscles in this fluid have the
same character as the lymph -
globules, 259; necessity of exa-
mining this fluid in researches as to
the office of the thymus, 259, 281.
See Corpuscles, Lymphatic Vessels,
and Thymus Gland.

in the cells of the thymus similar to
that in its lymphatic vessels, 260.

diminished in the thymus of diseased
and ill-fed animals, 261. See
Thymus Gland.

Fluidity of the blood, effect of salts in pre-
serving the, 13. See Blood, &c.

of the blood long after death, 17,

and after extravasation, 17.
Foetus without a heart, circulation in,

124,125.
FOHMANN, on the passage by veins of the

chyle in the seal, 179.

FOLKES, MARTIN, communicated the
tables by DAVIES, of specific gra-
vities, to the Royal Society, xl.
Foot, lymphatics of, 128.
FORDYCE, Dr. GEORGE, on the inflamma-
tory diathesis and buffy coat of the
blood, xxxvii-xxxviii.

used the term coagulable lymph,
xxxvii-viii.

on its properties, xxxvii-viii.

on the three parts of the blood,
xxxviii.

MS. notes of his lectures referred to,
xxxviii.

adopts the views of DAVIES on the
parts of the blood, xli.

on the coagulation of buffy blood,
34.

on the effect of rennet on serum, 80.

WILLIAM, on white orchylous blood

or serum, 85.
FOTHERGILL, Dr., 65.

referred to on white serum, 83.

FOURCROY, supposed that heat is pro-
duced by the coagulation of the
blood, xlii.

on the effect of caloric on coagu-
lation of the blood, 18.
FRACASSATI, on the effect of air on the

colour of the blood-clot, 7.
France, HEWSON'S visit to, xvi.
FRANKLIN, Dr.f signs HEWSON'S certifi-
cate for the Royal Society, xvi.
letter from to Dr. HUNTER on the
disagreement with HEWSON, xvii.
his character of HEWSON, xix.
on the print of HEWSON, xix.
his friendship with Mrs. HEWSON,

xx-xxi.

Fox, rigidity of limbs in the hunted, 21.
red corpuscles of the blood of, rather
smaller than those of the dog, 218.
Freezing, effects of on coagulation, 17, 18.
and thawing, effects of on the coagu-
lation of the blood, 19, 21, 25.
animals revived after, 19.
FRENCH, Mr., his case of white serum, 83.
FREIND, Dr., an early observer on the

effects of salts on the blood, 11.
Frogs kept long without food, blood and

lymph of not coagulating, 161.
Frozen animals revived, 19.

GABER, on the buffy coat of the blood, xxx.

on fibrin and serum, 30.
Gall-bladder, transudation of bile through,

169, 173. See Transudation.
GARTSHORE, Dr., referred to on white se-
rum, 83.
GAUBIUS, distinguished the three parts

of the blood, xxxiv.
his description of the crassamentum,

xxxiv.

on the inflammatory diathesis, xxxiv.
on the buffy coat, the fibre, serum,
and red globules of the blood, xxxv.
on the coagulation of the blood, xxxix.
on the effect of heat and motion on

coagulation, 18.
on fibrin and serum, 30.
cited in opposition to LEEDWEN-
HOEK'S view of the compound na-
ture of the red corpuscle of the blood,
227 ; considered them as oily, 227.
on the increase of fibrin in the blood

during inflammation, xxxv, 2.
GAVARRET, on the blood of the horse, 40.
Geese, milk -like serum in, 84, 89.
chyle of, 89. See Goose,
properties of the fluid of the lympha-
tics and of the serous sacs in, 160.
GENDRIN, on the serum of buffy blood, 38.
Genitals and groin, lymphatics of, 129.

22

338

GENERAL INDEX.

GIBSON, on white or chylons blood or

serum, 85.
Glaire, the term used for the coagulable

lymph of the blood, xxxi.
Gland, to what parts the terra is applied,

255.

Gland, thymus, increases in size afterbirth,
in healthy animals, but diminishes
in ill-nourished ones, 246. See
Thymus Gland.

Glands, without regular excretory ducts,
notice of HEWSON'S observations
on, xlvii.
Glands, conglobate or lymphatic, 127. See

Lymphatic Glands,
corpuscles in the fluid of, see Cor-
puscles.
Glands, mesenteric, see Mesenteric

Glands.

Glands, salivary and mammary, on the fol-
licles of, 190-1.
radical vesicles of, 191.
acini of, HEWSON'S injections, 191.
Glands, supra-renal, reference to observa-
tions on the office of, 255.
Glandula pituitaria, and pinealis,not lym-
phatic glands, 139.
GLAUBER'S salt, mixed with blood to keep

it fluid, 11.
GLISSON, Dr. FRANCIS, on the use of the

lymphatic vessels, 121.
what he says of nature, 167.
on the office of the lymphatics, 182,

186.
on the pale blood of the embryo of

vertebrata, 222.
on the use of the thymus, 261.
Globosae vesiculae, the red corpuscles of
the blood, so called by BIDLOO,
xxvii.
Globules, the fibrils of fibrin supposed to

be composed of, xli-xliii, 14.
of the serum, lymph, and red blood,
LEEUWENHOEK'S notions of, 157.
supposed series of in animal fluids,

182.

red, of the blood, 211. See Cor-
puscles.

Gluten, xxvi, xxxvi. See Fibrin.
GMELIN, on the coagulation of the blood

of the splenic vein, 269.
on the use of the spleen, 273.
Goat, on the size of its blood-discs, 218.
GOODSIR, Mr. J., his researches on cells

referred to, 170.

on absorption and ulceration, 179.
cited on the structure of intestinal

villi, 181.

on the structure of the lymphatic
glands, 250.

Goose, contraction of cervical lymphatics

in the, 125.

two thoracic ducts in, 144.
lymphatic system of, 144, 145.
nuclei in the red corpuscles of the
• splenic blood of, 283. See Geese.
GORDON, Dr., on the three parts of the

blood, xlii.

GRAINGER, Mr., opposed Sir EVERARD
HOME'S hypothesis on the red cor-
puscles and fibrin of the blood, xlii.
on increase of fibrin in buffy blood, 2.
referred to on Mr. KEY'S experiments,

47.

Grasshopper, blood-corpuscles of, 234.
Gravy of cooked meat, supposed to be the
serosity of the blood, 79. See Serosity.
Groin, the glands of the described, 129.

and genitals, lymphatics of, 129.
Growth and nutrition, use of fat in, 88.

agency of cells in, 179.
GRTJBY referred to, 14.
Guinea, flatness of the blood-corpuscles

compared to a, 215.
GrjLiELMiNi,his microscopic examination

of the blood-clot, xxvii.
GURLT, on red corpuscles inthe chyle, 277.
Guy's and St.Thomas's Hospitals, HEWSON
a pupil at, xv.

Haddock, description of the lymphatic

vessels in, 151-4.

HAEN, Professor DE, confounded coagula-
ble lymph with serum, xxx.

on clear coagulable fluid in a sac in

the crassamentum, 49.
HAHN, Dr., his preface to Latin edition of
HEWSON'S works referred to, xiii.
HALES, the Rev. Dr. STEPHEN, epistle to
by Dr. DAVIES to, xl.

escape of vermilion into the bowels

in an injection by, 173.
HALL, Dr. MARSHALL, on the blood

during hybernation, 52.
HALLER, supposed fibres to be generated
from the redpart of the blood, xxvii.

on the coagulation of the blood, xxix,
xxxix, xl.

on the buffy coat of the blood, xxx.

on colour of arterial and venous blood,
7-8.

described serum as self-coagulable,30.

on the question whether the lympha-
tic vessels are absorbents, 121.

on the properties of the fluid of the
serous sacs, 158.

on the arguments for and against ab-
sorption by veins, 176, 177.

considered the red corpuscles of the
blood as solid, 220.

GENERAL INDEX.

339

HALLER, (continued.)

refuted the opinion that the blood-
corpuscles are particles of oil, 227.
on the size of the lymphatic glands

at different ages, 246.
on the fluid of the lymphatic glands,

252,

referred to on the thymus, and its
fluid, 256, 258, 260 ; and on the
spleen, 265.

Ham, lymphatic- glands of, 130.
HAMBERGERUS, on the office of the lym-
phatics, 183.
HANDYSIDE, Dr., on absorption by veins,

180.

Hanging, effect of on the coagulation of
the blood, 68, 69 ; and on the
stiffening of muscle, 69.
state of the blood in the splenic vein

of a dog killed by, 269.
HANDLEY, JAMES, on the effects of salts

on the blood, 11.
Hare, state of the blood and muscles in a

hunted one, 21.
Harvest mouse, size of the red corpuscles

of its blood, 2 18.

HARVEY, on the parts of the blood, xxv.
on the colour of arterial and venous

blood, 10.

on effect of cold on coagulation, 17.
on the buffy blood of the horse, 40.
his term mucago, 232.
HAUGSTED, Dr., referred to on the struc-
ture of the thymus, 257.
on the development of the thymus,

261.
HAWKESWORTH, Dr., intimacy, of Mrs.

HEWSON with, xx.
HAWKINS, Mr. C., on extravasated blood

long remaining fluid, 17.
HAYGARTH, Dr., HEWSON writes a letter
to on the red corpuscles of the
blood, &c. xxiv, xxv.
note by, from Dr. MONRO'S Lectures,

on the lacteals of birds, 102.
letter from HEWSON to, 287.
Head and neck, lymphatics of, 138-40.
Heart, polypi of blood in, 23, 24, 37.

may be wanting and the blood cir-
culate, 124, 125.
lymphatic vessels of, 136.
Hearts, lymphatic, 126.
Heat, effect of on serum, xxv, xxvi, 28.
not the cause of the fluidity of the

blood, xxxiii, 18. See Cold,
required to coagulate the coagulable

lymph, xxxvii-viii,26-7, 82.
supposed production of in the coagu-
lation of the blood, by FOURCROY,
xlii; disproved by Mr. HUNTER, xlv.

Heat, (continued.)

effects of on the coagulation of blood,
3, 4, 51-2, see Cold ; and on con-
traction of muscle, 4.

effects of, on the separation of the
blood, 4, 71.

one cause of discrepancy in observa-
tions on the effects of on coagu-
lation, 5.

blood kept fluid from 139°-151°, 5.

its coagulation hastened at 120°, 1 22°-
126°, andat96°-114°, 5,6, 18.

required to destroy the self-coagu-
lating power of blood, 5 ; and of
salt and blood with water, 27.

colour of arterial and venous blood in
animals exposed to, 10.

animal, how high sometimes, 27.

effects of on a mixture of salt and
blood, 5-6, 27, 82.

animal, from combustion in the
lungs, 88.

animal, may be connected with the

red corpuscles of the blood, 235.
Hedgehog, on the vesicular roots of its
milk-ducts. 191.

blood of a torpid one, 53.
HEIDMANN, on motions in the fibrils of

fibrin in fresh blood, xlv.
HELLER, on white serum, 85.
Hematozine, colour of in different circum-
stances, 9.
Hemorrhages, treatment of, 57, 77.

how stopped, 76-77.

on the stopping of, 42, 46, 47.
HENDY, Mr., and Mr. FIELD, 63, 66, 67.
HENLE, Professor, on the relation of
lymph-corpuscles to the red cor-
puscles of the blood, xlvii.

on the effects of some substances on
the size of the red corpuscles, 9.

on buffy blood, 41.

on the coats of the arteries, 125.

his researches on cells referred to, 1 70.

cited on the structure of intestinal
villi, 181.

on the blood-discs as glandular cells,
235.

on the formation of red corpuscles of
the blood from pale ones, 254.

on lymph-corpuscles in the lymphatic

vessels, 278.

HENRY, Dr., used the term gluten for the
fibrin of the blood, xxxvi.

on the fibres of fibrin as distinguish-
ing it from albumen, xlv.
HERON, the maiden name of HEWSON'S

mother, xv.

HEWSON, Mr., references to published
notices of him, xiii.

340

GENERAL INDEX.

HEWSON, Mr. (continued.)
a native of Hexham, xiii.
educated at the grammar-school

there, xiv.

pupil with Mr. LAMBERT at New-
castle, xiv.
his father, mother, and their family,

xiv, xv.
goes to London and lodges with Mr.

HUNTER, xiv, xv.
attends Dr. HUNTER'S lectures, and

becomes his assistant, xv.
a pupil at Guy's and St. Thomas's

Hospitals, xv.

his habits and manners, xv, xvi.
studied at Edinburgh, xiv, xv, 92.
returns to London and becomes Dr.

HUNTER'S partner, xiv, xvi.
lived in Litchfield street, where

their school was, xvi.
went to France, and returned through

Flanders and Holland to London,

xiv, xvi.
went to Sussex to make experiments

on fishes, xvi.

his election into the Royal So-
ciety, xvi.
lived in Windmill street, and lectured

with Dr. HUNTER there, xvi.
his marriage to Miss STEVENSON,

xiv, xvi.
partnership between HUNTER and

HEWSON dissolved, and HEWSON

lectures on his own account, xvi.
his success, xvii, xviii.
letter on the disagreement between

HUNTER and HEWSON, xvii.
his death, xiv, xviii.
buried at St. Martin's-in-the-Fields,

xix.

his, character, xiii-xv, xix.
his children, xiv, xviii, xxi.
his person, xix.
engraving of him, xix.
his bust in a picture at Bolt court, xix.
notice of his widow, xx.
account of his writings, xxi et seq. ;

and list of, xlix.
his paper on paracentesis thoracis,

xxi.
papers on the lymphatic system in

oviparous vertebrata, xxi, xxiii.
his controversy with Dr. MONRO,

xxi-iii, 91.

his preparations of lymphatics of ovi-
parous vertebrata, xxiii.
award of the Copley medal to,

xxiii-iv.
publication of his papers on the pro'

perties of the blood, xxiv.

HEWSON, Mr. (continued.)

-first publication of his observations on
the red particles of the blood, and
on the uses of the lymphatic glands,
thymus, and spleen, xxiv.

his letter to Dr. HAYGARTH, xxiv-v,
287.

had a just view of the nature of false
membranes, xxv.

notice of his inquiries concerning the
properties of the coagulable lymph,
the comparative sinking of the red
corpuscles in it and in serum, and
on the pathology of the lymphatic
system, xxxviii-ix.

his work on the properties of the blood
characterized, xli. .

his clear proofs of the opinion of
DAVIES, that the coagulation of
the blood is alone dependent on the
fibrin, xli, xliii ; though even lately
ascribed to Mr. HUNTER, xliv.

separated the fibrin by salts, which
he well knew preserve the integrity
of the red corpuscles, xli, xliii ; and
by skimming the coagulable lymph
from the surface of blood during
the formation of the bufiy coat, an
experiment since wrongly claimed
for Mr. HUNTER, xliv.

publication of the third part of his
Inquiries, xlvi.

notice of his observations on the red
corpuscles of the blood, xlvi.

on the pale corpuscles of the blood,
and on the corpuscles in the fluid
of the lymphatic system and of the
thymus, xlvi.

on the lymphatic vessels of the thymus
and spleen, xlvi-vii.

on red corpuscles in the splenic
lymph, and in that of the lymphatic
system generally, xlvii.

on the office of the spleen, and of
other glands without excretory
ducts, xlvii; and on his doctrine of
central particles, and the relation
between the lymph-globules and
the red corpuscles of the blood,
xlvii, 254.

generous fidelity of MAGNUS FAL-
CON AR to, xlviii.

his central particle and the cell-nu-
cleus of the present day, xlvii-
xlviii.

his style and matter, and rank as a
physiologist, xlviii.

his note as to the date of his obser-
vations on the coagulable lymph,
41.

GENERAL INDEX.

341

HEWSON, Mr. (continued.)

considered the globules of the thymus
fluid as central particles or nuclei,
xlvii, 254.
saw the pale corpuscles in the blood,

282.
HEWSON, Mrs., her letter about her

husband, xiii.
circumstances in which she was left

when he died, xiv.
notice of, xx.

HEWSON, Dr. THOMAS TICKELL and WIL-
LIAM, sons of HEWSON, xiii, xxi.
Hexhain, HEWSON a native of, and edu-
cated there, xiv.
his father a surgeon-apothecary there,

xiv.

the Rev. Mr. BROWN of, xiv.
HEY, Mr., his repetitions of HEWSON'S
experiment of skimming off the
liquor sanguinis from the red cor-
puscles during the formation of
the buffy coat of the blood, xliv.
on increase of fibrin in the blood

during inflammation, 11, 40.
on effects of cold on coagulation, 48.
on the coagulation of blood from

slaughtered animals, 47.
found that the ligature kept on the
arm does not produce a buffy
coat, 67.
HILAIRE, ST., on white or chylous blood,

or serum, 85.
HOBSON, Dr., on the blood-corpuscles of

monotremata, 218.

HODGKIX, Dr., and Mr. LISTER, their ob-
servations on the red corpuscles of
the blood opposed to Sir E. HOME'S
hypothesis, xiii.

on the thickness and central de-
pression of the red corpuscles
of the blood, 215-16.
described the rolls of the red cor-
puscles of the blood, 221.
HOFFMANN, Mr., on the colour of the

blood, 8.

FREDERIC, on absorption by lympha-
tics, 121, 183.

Holland, HEWSON'S visit to, xvi.
HOME, Sir EVERARD, on the corpuscles

in fibrin, xxviii.

his hypothesis that the fibres of fibrin

are formed of colourless nuclei of

the red corpuscles of the blood, xli,

235.

ou the action of pus on muscular

fibre, 165.

described the colourless part of the
red corpuscle of human blood, 223.
Dr. FRANCIS, on the parts of the
blood, xxix.

Horse, the blood of, regularly buffy, 40.
serum of the blood of the, causes a
clumping of the red corpuscles of
another animal, 215.

clumping of the red corpuscles in
the blood of, 221.

on the blood of the portal vein in

. the, 269.

colour of the contents of the thoracic
duct of the, 276, 277 ; and of the
splenic lymph, 276.

blood of the, sinking of the red cor-
puscles in, 34.
Hospitals, Guy's and St. Thomas's,

HEWSON a pupil at, xv.
Hot springs, heat of in which fish live, 27.
HOULSTON, THOMAS, on the three parts
of the blood, xxxvii.

on the tenuity of the blood in in-
flammation, xxxvii.

on the heat required to coagulate

the coagulable lymph, xxxvii.
HUCK, Dr., 69.
HULL, Mr., note by from Dr. MONRO'S

lectures on lymphatics, 103.
Humming-bird, size of its blood-corpus-
cles, 219.
Hunted animals, coagulation of the blood

and stiffening of muscles in, 21.
HUNTER, Dr., his life by Dr. SIMMONS

referred to, xiii.

• HEWSON attends his lectures and be-
comes his assistant, xv.

gives HEWSON a letter to the pro-
fessors at Edinburgh, xv.

signs HEWSON'S certificate for the
Royal Society, xvi.

his school in Windmill street, xvi.

letter to on the disagreement be-
tween him and HEWSON, xvii.

his commendation of HEWSON'S in-
quiries on the lymphatic system of
oviparous vertebrata, xxiv.

on the different parts of the blood,
xxxvi.

used the term gluten for the fibrin,
and denied that it is fibrous, xxxvi.

description of a clot in an aneurism,
xxxvi.

date of his knowledge of the gluten,
xxxvi, xl.

on adhesions of parts in inflamma-
tion by a mucus, xxxvii.

his use of the term lymph, xxxvii-

his knowledge of the nature of false
membranes, xxxvii, 162.

on pus produced without ulceration,
xxxvii, 162.

his views on the parts of the blood
similar to those of DAVIES, xl,
xli, xiii.

342

GENERAL INDEX.

HCNTER, Dr. (continued.)

on colour of arterial and venous
blood, 7.

on faintness in hemorrhages, 46.

referred to on white serum, 83.
Ton transudation of lymph, blood, and
bile, 166-7.

cited on repetitions of KAUW BOER-
HAAVE'S experiment on absorption
by veins, 176.

his experiments in which injections
burst from the arteries into lym-
phatic vessels, 179.

his controversy with Dr. MONRO on
the lymphatics, 120, 182.

on the lymphatics being a system of
absorbents, 183-4.

state of his knowledge of absorption
and of some of the properties of
the blood in 1757, 183-4.

on the notion of lymphatics being
continued from arteries, 187.

on the effect on lymphatic glands of
absorption of matter from joints,
201.

case of emphysema by, 292.
HUNTER, Mr., HEWSON a lodger with, xv.
goes abroad and is succeeded by
HEWSON in Dr. HUNTER'S dis-
secting-room, xv.

his researches on the organization of
the blood-clot or fibrin, xxv, xlt.

observed that the fluidity of the
blood is not caused by its heat,
xxxiii.

adopts the viewsof DAVIES,HEWSON,
and Dr. HUNTER, on the parts of
the blood, xli, xlii.

incorrectly claimed the discovery of
the serosity, xliv, 79.

the discovery of the coagulable lymph
and of the paleness of the blood
of young embryos of vertebrata,
wrongly awarded to him, xliv-v,
222.

his views on the connexion of life
with the coagulation of the blood,
xlv, 21.

good description by, of the structure
of a clot of fibrin, xlv ; on the or-
ganization of, xxv, xlv.

disproves the opinion that heat is
produced in the coagulation of the
blood, xlv.

his observation on the aggregation
of the red corpuscles and on the
coagulation of the blood during
the formation of the buffy coat,
xlv, 34.

his experiment on the effects of a heat
of 150° on coagulation of blood, 5.

HUNTER, Mr. (continued.)

on the darkening of arterial blood by
stagnation, 11.

on the effect of agitation on the co-
agulation of the blood, 16.

on extravasated blood remaining long
fluid, 17.

noticed the blood of a fish coagulate
at a warmer temperature than in
the living body, 18.

on effects of freezing on coagulation
of blood and contraction of muscle,
18 ; and of warmth, 4, 5, 18.

on animals frozen to death, 18.

on coagulation of the blood in vacuo,
20.

on the causes which prevent the co-
agulation of blood and the con-
tractility of muscle, 20.

on slow coagulation of blood in living
vessels, 23.

follows HEWSON in the experiment
of separating the fluid self-coagu-
lating principle from the blood, 32.

on the specific gravity of the corpus-
cles and serum in buffy blood, 38.

oh the serosity in buffy blood, 39.

on the blood of torpid bats, 52.

his experiments on the serosity, 79.

on white serum, 85.

discovered the lymphatics in the
necks of birds, 102, 145.

on the structure and functions of
arteries, 125.

on Dr. HUNTER'S claim to the dis-
covery of the office of the lympha-
tic vessels, 182.
Hunterian Professor, his incorrect claims

for Mr. HUNTER, xliv-v.
HuTCHiNSONonwhiteorchylousserum,85
HUXHAM, Dr., on the buffy coat of the

blood, xxix, 30.
Hyaena, like the dog in the size of its

blood-discs, 218.
Hybernation, state of the blood in animals

during, 52.

Hydrocarbon, effect of, on coagulation, 20.
Hydrocele, fluid of, 73. See Fluid.
Hydi-ogen, said to darken the blood, 8.
Hypertrophy of articular cartilage, 179.

Ileum, villi of, 188.

Imbibition through veins, lymphatics, and
other tissues, 179, 199. See
Transudation.

Inflammation, supposed thinning of the
blood or liquor sanguinis in, xxxi,
xxxv, xxxvii, 33, 34, 37, 40, 58, 75.
matter of the buffy coat of the blood
in, supposed to be formed at the
expense of the red corpuscles, xxxi.

GENERAL INDEX.

343

Inflammation, (continued.')

of serous membranes, Dr. HUNTER'S

description of the effects of, xxxvii.

fibrin increased in the blood in, and

the red corpuscles diminished in, 2.

coagulation and consistency of the

blood in, 33-6. See Buffy Coat,
state of the red corpuscles in, 34.
thinning of the blood in, 37.
consistency of the liquor sanguinis

in, 41. See Buffy Coat,
state of the red corpuscles in, 41.
effect of saline medicines on the blood
in, 41. See Salts, and Buffy Coat,
of lymphatics, 126, 201.
Inflammatory crust, size, or pellicle, 30.

See Buffy Coat,
diathesis, G AUDI us and Dr. GEORGE

FORDYCE on, xxxiv, xxxviii.
Inguinal lymphatic glands described, 129.
Insects, larvae of, revived after freezing, 19.
blood-corpuscles of, 211-12, 288;

and their colour, 233-4, 290.
Inspissation of serum by evaporation, 79.

of coagulable lymph, 79-80.
Intestines, lymphatics of, 133.

villi of, 187-8.

Invertebrata, on the blood-corpuscles of,
211-12. See Corpuscles, and Insects,
blood of, fibrin formed in, 235.
blood of, pale, and so also in the
amphioxus, 234, 273.

Jejunum, villi of, 188.

Joints, atrophy and hypertrophy of the

cartilages of, 179.

JOLYFFE, Dr., on the lymphatics, 120.
JONES, Mr. WHARTON, on the conversion
of red corpuscles of the blood into
fibrin, xxviii, xxxi, xli, 2.
on buffy blood, 34, 38, 41.
on the development of the blood-
corpuscle, 212.
his figures of the rolls of blood-discs

referred to, 221.
on the office of the red corpuscles of

the blood, 235.
Jugular veins, effect of tying the, 175.

effect of extirpating the, 175.
JURIN, on the coagulation of the blood,

xxviii-ix.
on the specific gravity of the red

corpuscles of the blood, xxxv-vi.
on the specific gravity of serum, 78.

KEILL, Dr. JAMES, on the coagulation of

the blood, xxviii-ix.
Kid, ERASISTRATUS on the lacteals of a,

120.
between an ibex and goat, size of the

blood-corpuscles of, 233.

Kidney, lymphatics of, 133.

spleen, and liver, lymphatics of, 133-4.
corpora globosa of, 190.
KIRKLAND, Mr., on the stopping of bleed-
ing from arteries by their contrac-
tion, 47.
KNOX, Dr., on the lacteal system in the

seal, 179-80.
KOLK, VAN DER. See SCHROEDER.

Lactea primi generis, et lactea secundi

generis, 133.

Lacteal vessels, fibrin formed in the, 235.
question of the discovery of, in ovi-
parous vertebrata, xxii, 102.
in birds, discovery of, 102.

ASSELHUS, PECftUET, RuDBECK,

and BARTHOLIN on the, 119-20.
ERASISTRATUS on, 120.
contraction of, 126.
how to see the, 123.
contents of, in mammals, not always

white, 123.

contents of, in birds, limpid, 123.
coats of, 124-6.
in man, their commencement, course,

and termination described, 132-4.
in birds, strictly the lymphatics of

the intestines, 144.
in amphibia, 147.
supposed to carry chyle to the liver,

xxii, 172.
mercury passing from, into veins, 177,

178.
supposed open orifices of, in the villi,

181.

on the use of the, 181.
loops or closed ends of, in the villi,

181.
supposed orifices of, in the villi, 189,

192-4.
often pass by, instead of through, the

mesenteric glands, 137.
description of, in a turtle, 250.
LAMBERT, Mr., HEWSON a pupil of, at

Newcastle, xiv.

LAMBERT, Mr., his case of white serum, 83,
Lancelet, colourless blood of, 234.
LANE, Mr., on the coagulation of the fluid

of the lymphatic vessels, 159.
referred to on the power of endos-

mose and exosmose of the blood-
corpuscles, 215.
description by, of the colourless part

of the red corpuscles of human

blood, 223.
on red corpuscles of the blood in the

lymphatic vessels, 276.
LANGRISH, Dr. BROWN, on the coagula-
tion of the blood, xxviii-ix.
Larvae of insects, revived after freezing, 19.

344

GENERAL INDEX.

LAUTH, his microscopic examination of

the fibrils of fibrin, xlv.
Lectures attended by HEWSON, xv, 92,

93, 102, 109, 110.
Leeches, frozen, reviving, 19.
Leg, sometimes a lymphatic gland in the
lower part of, -130.

and thigh, lymphatics of, 128.
Letter by Mrs. HEWSON about her hus-
band, xiii.

from FRAN KLIN to Dr. HUNTER on the
disagreement with HEWSON, xvii.

from HEWSON to Dr. HAYGARTH,

xxiv-v, 287.

LETTSOM, Dr., his life by Mr. PETTIGREW
referred to, xiii.

on HEWSON'S gratifying prospects,
xviii.

his commendation of HEWSON'S in-
quiries on the lymphatic system of
oviparous vertebrata, xxiv.
LEEUWENHOEK, probably saw either cells
in fibrin or the pale floating cor-
puscles of the blood, xxviii.

on the parts and coagulation of the
blood, xxix.

his doctrine on the blood taught by
the first Dr. MONRO, xxxiv; op-
posed by SENAC, xxxii ; by the
second Dr. MONRO, xxxiv ; and by
HEWSON, xlvi.

ill effect of the speculations connected
with his microscopical researches,
xxxix.

his hypothesis finally exploded by
HEWSON, xlvi.

his notions on the globules of lymph,
serum, and red blood, 157.

on the supposed series of globules in
animal fluids, 182.

considered the red blood-corpuscles
of man as spherical, 211, 287 ; and
those of lower vertebrata as flat
and elliptical, 214.

did not know how to dilute the blood
to examine the corpuscles, 217.

on the size of the blood-corpuscles in
different animals, 217.

the indication in his figures of a nu-
cleus in the blood-corpuscles of a
fish, 222.

his noted view of the compound na-
ture of the blood-corpuscles, 226.

cited by SENAC as to the solvent
power of ammonia on the blood-
discs, 230.

on the pliancy of the blood-discs
when circulating in a narrow chan-
nel, 228-9.

on the blood-corpuscles of the grass-
hopper, 234.

LIEBIG, on albumen and fibrin, 44.

on the formation of fat in animals,

87.

on the use of fat in respiration, 88.
LIEBERKUHN'S plates of villi of the intes-
tines referred to, 188, 189, 192.
his experiments on the ampullula,190.
Life, Mr. HUNTER on its connexion with
the coagulation of the blood, xlv, 2 1 .
frozen animals returning to, 19.
Ligature on the arm said to produce the

buffy coat on the blood, 65-8.
on the vena cava and on the jugular

veins producing dropsy, 174-5.
Lightning, effect of, on the coagulation of
blood and contractility of muscle,
20. See Blood, Coagulation, &c.
Lion, villi of intestines of, 187.

glomeruli of the kidney of, 190.
Liquor sanguinis, the term used in Eng-
land before MULLER'S experiment
of filtrating the frog's blood was
known, xiii, xliii.

effects of heat on the coagulation of,
either pure or mixed with salt, 5,6;
or when the mixture is diluted with
water, 6. See Heat,
coagulation of, retarded when sepa-
rated from the red corpuscles, 34.
consistency of, in inflammation, 34, 40.
Dr. BABINGTON'S view of the, 73.
consistency of different parts of,
after its coagulation, 73. See Co-
agulable Lymph and Fibrin.
List of HEWSON'S writings, xlix.
LISTER, MARTIN, confounded serum with

fibrin, xxix.
on frozen larvae restored to life by

thawing, 19.

on the coagulation of the blood dur-
ing hibernation, 52.
on white or chylous blood or serum ,85.
LISTER, Mr., and Dr. HODGKIN, on the
thickness of the red corpuscle
of the blood, 215 ; and on its cen-
tral depression, 216.
their observations on the red corpus-
cles of the blood opposed to Sir E.
HOME'S hypothesis, xiii.
described the rolls of the red cor-
puscles of the blood, 221.
Litchfield street, Dr. HUNTER and Mr.

HEWSON'S school there, xvi.
LITTRE, M., his case of emphysema, 292.
Liver of fishes, increase of the oil in,

after death, 86.

lacteals supposed to end in the, 119.
spleen, and kidneys, lymphatics of,

133-4.

lacteals supposed to carry the chyle
to, xxii, 172.

GENERAL INDEX.

345

Living tissues, effect of, in retarding the
coagulation of the blood, xxxviii,
16. See Coagulation.

animals, coagulation of the blood in,
4. See Coagulation.

principle, blood said to coagulate by
its, 21. See Coagulation.

and dead parts, coagulation of blood
confined in, 23. See Coagulation.
Lobster, blood-corpuscles of, 233-4.
Loins, lymphatics of, 131.
LOWER, Dr. RICHARD, on the coagulation
of the blood, and on the coagula-
tion by heat of serum and lymph,
xxvi. See Coagulation, and Heat.

neglect of his observations on the
blood, xxxix.

on the effect of air on the colour of
blood, 7. See Blood.

his experiment of a ligature on the
vena cava and on the jugular veins
of a dog, 174, 175. See Dropsy.

on the fluid in the pericardium, 198.

LOWER and BOYLE, on milk-bike or chy-

lous blood or serum, 8 5. SeeSerum.

Lungs, colour of blood changed in, 10, 71.

combustion introducing animalheat,
88.

lymphatics of, 135-6.

on the source of the carbon exhaled
from, 235.

on wounds of the, 291. See Emphy-
sema.

not always wrounded when air escapes
from the chest, 299.

emphysema from abscess of, 301.
Lymph of the lymphatic vessels, LOWER
on its coagulation by heat, xxvi.

corpuscles of, see Corpuscles.

properties of, 157-61.

of the different cavities of the body,
properties of, 157-61.

fluid in the lymphatic vessels twenty-
four hours after death, and coagu-
lating when let out, 161.

time required for the coagulation of,
161 ; and in weak animals, 161.

not coagulating in frogs kept without
food, 161.

and chyle, course of, 123.

of the lymphatic vessels, of the blood,
and of serous sacs, compared, 161,
165, 185.

how secreted into cavities for their
lubrication, 166-7.

interstitial and of serous sacs, how
produced, 170.

passage of, along the lymphatics, 195.

coagulated, in the pericardium of
bullocks after death, 198. See
Fluid. •

Lymph, (continued.}

of the spleen, red colour of, 271, 272,

276,289.

coagulates when exposed, 272.
red particles in, 272.
Lymphatic ducts of the thymus, 281.
Lymphatic hearts, 126.
Lymph, coagulable, see Coagulable Lymph,

Fibrin, andBuffy Coat of the Blood.
Lymph-corpuscles, sizes of, see Measure-
ments and Corpuscles.
Lymphatic or conglobate glands, 127.
injected by NUCK, 120.
described as made up of a convoluted

lymphatic vessel, 178.
mercury passing from, into veins, 177-

178.

wanting in some animals, 127.
first publication of HEWSON'S views

as to, xxiv.
notice of HEWSON'S observations on

the use of, xlvii.
of the groin described, 129.
sometimes one in the leg, 130.
in the ham, 130.
in the loins, 132.
of the mesentery, 132.
bronchial, 135-6, 138; and others

in the chest, 138.
of the stomach, 137.
of the omentum, 137.
near the pancreas, 137.
of the pelvis, 137.
of the loins, 137.
near the spleen, liver, and kidneys,

138.
the lymphatic vessels often pass by,

instead of through, 137, 203.
of the head and neck, 139.
of the axilla and arm, 141.
wanting in the turtle and fishes, 154,

250.

present in the necks of birds, 154.
how affected by absorption of hurtful

matters, 200-2.

on the structure of, 178, 245, 247-51.
size of, in males and females, and

at different periods of life, and

in healthy and diseased persons,

246,

why sometimes not inflamed by ab-
sorbed poisonous matter, 248.
office of, 121, 127, 252.
corpuscles in the juice of, have the

same characters as the corpuscles

of the thymus fluid, 259.
the lymphatic vessels considered as

the excretory ducts of the glands,

251-2, 276.
secrete a fluid containing corpuscles,

251-2, 276.

346

GENERAL INDEX.

Lymphatic glands, (continued.)

envelope of the red corpuscles of the
blood formed in the lymphatics
emerging from, 275, 277.

lymph-corpuscles formed in, the office
of the glands being to form the
corpuscles, 277-8, 286, 289.

same office performed in amphibia by
a network of lymphatic vessels, so
that the corpuscles may be formed
independently of the glands, which
are appendages to the lymphatic
vessels, 278.

the thymus considered as an auxiliary
to, 279.

thymus compared to, in structure and
office, 260, 261, 279, 280.

corpuscles in the fluid of, not so
abundant as in that of the thymus,
281.

concern of, in nutrition, 281.

appendages to the lymphatic system,
289.

corpuscles in the fluid of, see Cor-
puscles, and Measurements.
Lymphatic system in birds, publication of
HEWSON'S papers on, xxi.

controversy as to discovery of parts
of, xxii.

our knowledge of it acquired by frag-
ments, xxii.

pathology of, notice of HEWSON'S
inquiries concerning, xxxix.

on the discovery of, in oviparous
vertebrata, 91.

history of discoveries in, 119, 120.

on the use of, 121, 181-5.

in birds, fish, and amphibia, 121.

general account of, 123.

the valves of, 126.

particular description of, in the
human body, 128-143.

description of, in birds, 144.

description of, in the turtle, 147.

description of, in a haddock, 151-4.

every part of it by some anatomists
supposed to be wanting in oviparous
vertebrata, 177.

pathological observations on, 196.

its strong claims to attention, 204.

discovery of, by RUDBECK and BAR-
THOLIN, 245.

the thymus considered as an appen-
dage to, 279-80.

Lymphatic vessels, supposed discovery
that they are the exclusive agents
of absorption, xxii.

contents of, in the thymus and spleen,
notice of HEWSON'S observations
on, xlvi-vii.

red corpuscles in, xlvii, 276-7.

Lymphatic vessels, (continued.)

fluid of, supposed to modify the blood
during its evacuation, 44.

coats of, 124-6.

subject to inflammation, 126.

of the foot, 128.

of the leg and thigh,. 129-31.

of the groin and genitals, 129.

of the pelvis, 131.

enlarged during pregnancy in the
womb, 131.

of the loins, 132.

of the intestines, 133.

of the kidney, 133.

of the stomach, 133-4.

of the liver, spleen, kidneys, and
pancreas, 133-4.

of the lungs, 135-6.

of the heart, 136.

of the head and neck, 138-9.

experiments to determine whether
the brain has them, 139.

of the back of the neck and shoulder,
140.

of the thyroid gland, 140, 143.

of the upper extremity, 140-3.

of birds described, 144.

in the necks of fowls, 145 ; discovered
there by Mr. HUNTER, 102.

of birds, how tobe demonstrated, 146.

in the turtle and in fishes, 151.

description of in a haddock, 151-4.

properties of the lymph contained in,
123, 157-61, 185, 196, 198.

fluid of, compared to coagulable
lymph of the blood, 165.

functions of, 180.

fibrin formed in, 235.

sometimes passby,instead of through,
the glands, 137, 203, 248.

considered as the excretory ducts of
the lymphatic glands, 251-2, 276.

of the thymus, white fluid in, with
corpuscles of the same characters
as lymph-corpuscles, 258-60 ; ne-
cessity of examining this fluid in
researches as to the office of the
thymus, 259, 281 ; the lymphatics
considered as its excretory ducts,
260-1 ; fluid of, similar to that in
the cells of the thymus, 260 ; on
the question of the passage into of
the corpuscles of the thymus fluid,
280-1 ; carry a fluid like that of
the thymus, 281.

of the spleen, 133, 269-71 ; contents
of them, 271 ; and their concern
in the formation of the blood-
corpuscles, 275-7; red colour of
the splenic lymph not constant,
276.

GENERAL INDEX.

347

Lymphatic vessels, (continued.)

lymph-corpuscles formed in the,espe-

cially in the amphibia, 278.
controversy on the office of, by

Drs. HUNTER and MONRO, 120.
of the stomach, supposed ^to end in

its veins, 134.

absorption by, 142, 199-204.
absorption may occur independently

of them, 142, 182 ; instances, 179*.
mercury passing from, into veins,

177-8, and from the arteries, 179.
supposed to be small veins continued

from the arteries, 182.
injections forced into, from the ar-
teries, 179, 184-5.
whether some of them may not be a

continuation of small arteries, 186,
supposed to be only veins, 186.
supposed orifices of, 194.
use of the valves of, 195.
passage of the lymph along, 195.
wound of, and nature of the fluid

flowing from, 198.
treatment of a wound of, 199.
arguments for absorption by, 199-204
inflamed from absorption of hurtful

matter, 201.

MAC BRIDE, Dr., as to the claim of priority

between FORDYCE and HEWSON

on the formation of the buffy coat

of the blood, xxxviii.

MACKENZIE, Dr. COLIN, attended on

midwifery by HEWSON, xv.
MADDOCKS, Dr., note by, from Dr. MON-
RO'S lectures on lymphatics, 103.
case by, of inflamed lymphatics, 201.
Mad dog, treatment of bite of, 202.
MAGENDIE, his microscopic examination

of the fibrils of fibrin, xlv.
MALPIGHI, on the constituents of the
crassamentum, on polypi, and on
the buffs7 coat of the blood, xxvi.
neglect of his accurate observations

on the blood, xxxix.

Mammalia, red corpuscles of the blood of,
have no nucleus, except in very
young embryos, tike that in the cor-
puscles of lower vertebrata, 222.
pale and membranous part of the
corpuscles, 223. See Corpuscles,
variations from the regular forms of

the corpuscles, 223, 225.
corpuscles oval in the camelidae, 218.
blood-discs of, run into rolls, 228.
softness and elasticity of the cor-
puscles, 229. See Corpuscles.

Mammalia, (continued.)

embryo of, blood-corpuscles in, larger
than they are after birth, xlvi, 233.
nucleus in the red corpuscle of the
blood only a temporary part, 275.
HEWSON observed the pale cor-
puscles in the blood of, 282.
sizes of the corpuscles of blood,
lymph, and pus of, see Measure-
ments.
Man, measurements of the red corpuscles

of the blood of, 216.
measurements of the pale corpuscles

of the blood of, 243.

measurements of the corpuscles of the

chyle, lymph, and thymus fluid,

and of the globules of pus of, 244.

pale and membranous base of the red

corpuscle of the blood of, 223.
MANDL, M., on the pale corpuscles of the

blood, 282.

Marasmus, not always produced by ob-
struction of the mesenteric glands,
137.
MARCET, Dr., on the specific gravity of

serum, 78. See Specific Gravity.
MARCHAND, referred to, 2.
MARHERR, PH. AMBR., on the coagula-
tion of the blood, xxix, xxxix.
on the huffy coat of the blood, xxx.
Marsupialia, form, size, and structure, of

the red blood-corpuscles of, 218.
MARTINE, Dr. GEO., on the coagulation

of the blood, xxviii-ix.
MASCAGNI, on the structure of the breast,

191.

MASKELYNE, Mr., on the council which
awarded the Copley medal to
HEWSON, xxiii.
MATY, Dr., signed HEWSON'S certificate

for the Royal Society, xvi.
on the council which awarded the

Copley medal to HEWSON, xxiii.
MAYOW, JOH., on the effect of air on the

colour of the blood, 7.
his nitro-aerial spirit, 7, 11.
Measurements of the red corpuscles of

the blood of mammalia, 237-9.
of the red corpuscles of the blood of

man, 216.

of the red corpuscles of birds, 239-42.
of the red corpuscles of reptiles, 242.
of the red corpuscles of amphibia,

242.

of the red corpuscles of fishes, 243.
of the red corpuscles of foetal or im-
mature animals, 243.
of the pale corpuscles of the blood
in the vertebrata, 243.

348

GENERAL INDEX.

Measurements, &c. (continued.}

of the corpuscles of chyle, lymph,
and thymus fluid in vertebrata,244.
of the globules of pus, 244.
MECKEL, Dr., on the lymphatic system,

120.
suggested that the lymphatics of the

stomach open into its veins, 134.
supported the doctrine of absorption

by veins, 177, 178.
on the structure of the lymphatic

glands, 178.
Medal, Sir GODFREY COPLEY'S, awarded

to HEWSON, xxiii, xxiv, 91.
Medical Society, picture of the early mem-
bers of, xix.
MEDLEY, S., picture by of the members

of the Medical Society, xix.
Membrane, RUYSCH'S, xxviii, xxx; formed
of the fibrin of the blood, xxv,
xlv, 14, See Fibrin,
supposed not to admit of transuda-

tion during life, 168, 169.
transudation through, 169, 170, 173.

See Transudation.

serous, Dr. HUNTER'S description of

the effects of inflammation on,

xxxvii. See Serous Membranes.

coated with coagulated lymph, 162.

containing pus and not ulcerated,

162, 164. See Ulceration.
Membranous and colourless part of the

red corpuscle of the blood, 223.
MERY, M., his case of emphysema, 292.
Mesenteric glands of the human subject,

137. See Lymphatic Glands,
obstruction of, does not always cause

a marasmus, 137.
of the whale, hollow in the centre,

250.
abundance of corpuscles in the fluid

of during digestion, 278.
Mesenteric veins, white chyle said to have

been seen in the blood of, 1 73.
mercury passing into, from the lac-
teals, 178.
in the seal, supposed route of the

chyle by, 179.

MICHELLOTTJ, PET. ANT., on the consti-
tuents of the crassamentum, xxvii.
Microscope, its usefulness in anatomy, 213.
BAKER'S, used by HEWSON, 214.
DELLA TORRE'S glasses, 214.
Milk-ducts, the vesicular roots of, 191.
Milk-like serum, 78, 82. See Serum.
Milk and serum, effects of boiling and of

rennet on compared, 80, 81.
Molecular base of the chyle, its characters
like those of the white matter float-
ing on blood and on serum, 82.

Molecules, minute, free cell-seeds or

within cells, fatty nature of, 88.
attached to red corpuscles of the

blood, or free, 225.
in the juice of the supra-renal glands,
reference to description and figures
of, 255.

Moles, or false conceptions, 25.
Monoculus, blood-corpuscles of, 234-5.
Monotremata, on the red blood-discs of,

218.

MONRO, Dr., primus, taught the doctrine
of LEEUWENHOEK on the blood,
xxxiv.
MONRO, Dr., secundus, controversy of

with HEWSON, xxi-xxiii.
opposed LEEUWENHOEK'S doctrine
on the blood, and taught the dis-
tinction between its different parts,
xxxiv

on his claim to the discovery of the
lymphatic system in oviparous ver-
tebrata, xxii, 91.
copy of his claim, 96.
on his claim to proposing the opera-
tion of paracentesis thoracis in
emphysema, 92, 291.
his argument for absorption by veins,

his experiments in which injections

burst from arteries into lymphatic

vessels, 179.
on the functions of the lymphatic

vessels, 180.
his controversy with Dr. HUNTER on

the office of lymphatics, 120, 182.
cited on the lymphatics, 174, 184.
cited on the question of the continu-
ation of lymphatic vessels from

arteries, 186-7.

cited on cancer of the breast, 231.
his objections to HEWSON'S view on

the office of the spleen, 273.
on the properties of the fluid of the

serous sacs, 158.

on wounds of the lymphatics, 199.
DONALD, on his brother's claim to

the discovery of the lymphatic

system in oviparous vertebrata, 95,

111.

Mouths, supposed, of the lacteals, 181.
MORGAGNI referred to on white serum, 83.
on the size of the lymphatic glands

at different ages, 246.
MORGAN, Dr. THOS., on the coagulation of

the blood, xxviii, xxix.
Dr. JOHN, note by, froniDr.MoNRo's

lectures on lymphatics, 109.
described pus as a secretion, 162, 165.
Mouse, size of its blood-discs, 218.

GENERAL INDEX.

349

Mucago, a term used by HARVEY for co-

agulable lymph, 232.
Mucilage, used for coagulable lymph, and

for the coagulable matter of the

serum, xxvii, 78-80, 232.
Mucus, in the blood, the inflammatory

diathesis attributed to, xxxiv.
the term used for coagulable lymph

by Dr. HUNTER, xxxvii.
MULDER, on the relation of lymph-corpus-
cles to the red corpuscles of the

blood, xlvii. •
on the effects of oxygen, &c. on the

colour of hematozine, and on the

red corpuscles of the blood, 9.
on the composition of albumen and

fibrin, 31.

on the action of oxygen on fibrin, 81.
MULLER, Professor, states the belief on the

Continent that the coagulation of

the blood is produced by the red

corpuscles, xliii.
his methods, one of which was used

by HEWSON, of separating the

liquid fibrin from the red corpuscles

of the blood, xliii-iv.
the term liquor sanguinis in use before

his experiment was known, xliii-iv.
on lymphatic hearts, 126.
on the coagulation of lymph, 159.
on the loss of the coagulating power

in the blood and lymph of frogs

kept without food, 161.
on the intestinal villi, 187, 189.
referred to on the structure of glands,

191.
on the ruddy colour of the splenic

lymph, 273.
on the absence of the spleen in some

fishes, 273.
on the colourless blood in the amphi-

oxus, 273.
on the formation of lymph-corpuscles

in the lymphatic vessels, 278.
Muriatic acid, dilute, puckers the envelope

of the red corpuscle of the blood,

223.
Muscle,contraction of promoted by warmth,

4.

effect of salt on contraction of, 13.
causes said to destroy its contractility,

20, 21.

stiffening of in hunted animals, 21.
rigidity of after death from hanging,

drowning, suffocation, and light-
ning, 20, 69.

Musk-deer, its minute red blood-discs, 2 19.
the lymph-corpuscles of, larger than

the red corpuscles of the blood,

253-4. See Corpuscles.

MUYS, on the effects of serum and water
on the red blood-corpuscles, 215.
on the central depression in blood-
corpuscle, 216. See Corpuscles.

Myxine, spleen wanting in, 273.

Napu musk-deer, see Musk-deer.
NASSE, Professor HERMANN, on the re-
lation of lymph-corpuscles to the
red corpuscles of the blood, xlvii.
on effects of salts, &c. on the size of

the red corpuscles, 9.
onbuffyblood,34,41.
Nature, what GLISSON says of her, 167.
Neck and head, lymphatics of, 138-40.
NEEDH AM, Dr. Gu ALT., on animal heat, 88.
on the pale blood of the embryo of

vertebrata, 222.
Neutral salts, their action on the blood in

inflammation, 71, 72. See Salts.
Newcastle, HEWSON a pupil of Mr.

LAMBERT'S at, xiv.
NEWPORT, Mr., on the blood-corpuscles of

invertebrata, 211-12.
on the blood-corpuscles as glandular

cells, 212, 235.

Nitre, hypothesis of air containing, 11.
its use in hemorrhages, 57.
SEN AC, on the effects of on the co-
agulation of the blood, xxxiii.
Nitro-aerial spirit, MAYOW'S, 7, 11.
Nitrogen, see Azote,

Nitrous gas, effect of, on coagulation, 20.
Nitrous oxide, effect of on coagulation, 20.
NoGUEz,P.,on the office of the lymphatics,

182-3.

Non-vascular parts, nourishment and ab-
sorption of, 179.
NORTH COTE, William, on the crassamen-

tum, xxix.
NUCK, Dr. ANTON., his injections of the

lymphatic glands, 120.
on the valves of the lymphatic system,

126-7.
his representation of the lymphatic

vessels of the heart, 136. "
his view of the function of the lym-
phatic vessels, 182.
on the supposed continuation of lym-
phatic vessels from arteries, 186.
Nucleoli of cells, fatty nature of, 88.
Nucleus of the red corpuscles of the blood,

221,274.

of the red corpuscles of the blood
of the lower vertebrata, xlvi, 216,
222-3.
hypothesis that the fibrin is formed

of the nuclei, xli, xliii, 235.
or central particle, notice of HEW-
SON'S doctrine of, xlvii.

350

GENERAL INDEX.

Nucleus, (continued.)

the corpuscle of lymph and of the
thyraus fluid considered as, 254.

wanting in the blood-disc of mam-
mals, 222-3, except in young em-
bryos, 222.

seen to escape from the vesicle, 226.

effects of water and of acetic acid on,
224, 253.

shape of in the blood-disc of birds,
compared with the lymph-cor-
puscle, 225, 253.

mode of showing, 232.

how seen in the vesicle like a pea in
a bladder, 274, 288.

adhesion between the envelope and
nucleus, 275.

temporary in mammals, and perma-
nent in lower vertebrata, 275.

of the blood-disc and the lymph-
corpuscle of birds compared, 253,
279.

of the blood-discs of fishes, 234.

the lymph-corpuscles considered as
nuclei or immature cells, 254, 281.

in the red corpuscle of a bird's splenic

blood, 283. See Corpuscles.
Nutrition and growth, use of fat in, 88.

importance of fat in, 280.

concern of the thymus and lymphatic
glands in, 281.

agency of cells in,' 179.
Nutritious qualities of fat, 87.

(Edema of lower limbs connected with ob-
struction of veins by coagulated
blood, 24, 174-5.

(Esophagus, villi described in, 188.

OESTERLIN considers the globules of the
thymus fluid as nuclei, 254.

Oil, absorption of, supposed to cause
milky serum, 86, 87. See Fat and
Serum.

coagulation of blood covered with, 20.
increase of in olives after fermenta-
tion, 86.
increases in the liver and muscles of

fishes after death, 86.
may probably be formed from al-
bumen, 86, 88. See Fat.
conversion of into a protein com-
pound, 88. See Fat.

OLDENBURG, account by, of a bitch that
had her spleen cut out, 273.

Olives, increase of oil in after fermenta-
tion, 86.

Ophidian reptiles, shape of the red cor-
puscles of the blood of, 312.

Orifices, old notion of their agency in ab-
sorption, 172, 179.

Orifices, (continued.)

supposed open ones in the lacteals

in the villi, 181, 189, 192-4.
ORRED, Mr., note by, from Dr. MONRO'S
lectures on lymphatics in birds,
102.

Ovary, fluid of in dropsy, 198.
Oviparous vertebrata, controversy as to the

discovery of lacteals in, xxii.
commendations of HEWSON'S papers
on the lymphatic system in, xxiii-iv.
nucleus of the red corpuscles of the
blood of, xlvi. See Nucleus, and
Corpuscles.

on the discovery of the lymphatic
system in, 91. See Lymphatic
System.

supposed by some to be entirely des-
titute of a lymphatic system, 177-8.
fissures in the blood-discs of, 226.
nucleus of the red corpuscles of the

blood a permanent part, 275.
formation of lymph-corpuscles in

lymphatic vessels of, 278.
OWEN, Professor, his incorrect claims for

Mr. HUNTER, xliv-v, 32, 222.
Owl, snowy, its blood-discs a narrower
ellipse than those of its con-
geners, 213.

Ox, coagulation of the blood of, 24.
villi of intestines of, 187.
cavities in the intestinal villi of, 187.
fluid in the pericardium of, 198.
size of the red corpuscles of the
blood of the, 2 18. See Corpuscles.
Oxide, nitrous, effect of on coagulation, 20.
Oxygen, effects of on the colour of the

blood, 8, 9, 10. See Blood,
discovery of, 11.
effect of on coagulation of the blood,

20. See Coagulation.
red corpuscles of the blood supposed
to be carriers of, 235.

PA GET, Mr., on the disposition of the
parts of the blood in clots or po-
lypi of the heart, 24. See Polypi,
referred to on the intestinal villi, 181.

Painting of the early members of the Me-
dical Society, xix.

Paleness of the blood of very young em-
bryos of vertebrata, xliv-v, 222.

PALFYN, his case of emphysema from an
abscess in the lungs, 301.

PALMER, Mr., on the blood of hyber-
nating animals, 52.

Pancreas and spleen, lymphatics of, 133.

Papillae of the true skin, 193.

Paracentesis thoracis, publication of HEW-
SON'S paper on, xxi.

GENERAL INDEX.

351

Paracentesis thoracis, (continued.)

on Dr. MONRO'S claim to proposing,

for emphysema, 92.
for air in the chest, HEWSON'S

paper on, 291.

best place for performing the ope-
ration, 301.
PARSONS, Dr., on HEWSON'S paper on

emphysema, 94.

Particles, red, of the hlood, on the figure
and composition of, 21 1. See Cor-
puscles,
central, in the fluid of the lymphatic

glands, 276. See Corpuscles,
in the lymphatic vessels, 277.
central, xlviii. See Corpuscles of the
Blood, Corpuscles of Lymph, and
Nucleus.

Passenger pigeon, its blood-discs a nar-
rower ellipse than those of its con-
geners, 313. See Corpuscles.
Passy, visit of Mrs. HEWSON to, xx.
PECQUET, Dr. J., on the thoracic duct,

119-20.

Pellea crusta, xxvi.
Pellicle on the blood when coagulation

begins, 59, 63, 73.
on heated serum and water, and on

milk, 80.

Pelvis, lymphatics of, 131.
Penis, argument from the structure of, for

absorption by veins, 174.
PEPYS, Dr., on HEWSON'S paper on em-
physema, 94.

Pericardium, the fluid in, old view of the
nature of, 157 ; properties of, xxvi,
158-60.
coagulates at the heat of the air when

mixed with serum of blood, 158.
quantity of the fluid in four human

subjects suddenly killed, 158.
coated with coagulated lymph, 162,

and not ulcerated, 162.
pus in, without ulceration, 164.
coagulated fluid in, 198. See Fluid.
Peritoneum, the fluid in, old view of the
nature of, 157 ; properties of, 158-
60. See Fluid.
PETIT, on the coagulation of the blood,

xxx, xxxix-xl. See Coagulation,
on the disposition of the parts of the
blood in the heart after death, 24.
PETTIGREW, Mr., his life of Dr. LETTSOM

referred to, xiii.
Pheasant, chyme of the, 87.
Philadelphia, Mrs. HEWSON removed to,

xxi ; her son a physician at, xxi.
Phlebitis commonly confounded with sof-
tening of fibrin, 24.

Picture of the early members of the Me-
dical Society, xix.

Pigeon, passenger, its blood-discs a nar-
rower oval than those of its con-
geners, 313. See Corpuscles.
Pike, shape of the blood-corpuscles of, 234.
Piles or rolls of the red corpuscles of the

blood, xh-i, 221,228.
Pineal gland not a lymphatic gland, 139.
PITCAIRN, Dr., cited on white serum, 83.
Pituitary gland not a lymphatic gland, 139.
Placenta, as to absorption in the, 175.
PLATES, description of the, 303-19.
Plethora, coagulation of the blood may be

retarded in, 59.
supposed connexion of reabsorption

of fat with, 89.
Pleura, old notion of the nature of the

fluid in, 157.
properties of, 158-60.
pus in, without ulceration, 164.
on wounds of the, 291.
Pleuritic crust, see Buffy Coat of the

Blood.
Poison, absorption of by branches of the

portal vein, 180.

venereal, sometimes enters the con-
stitution without producing a bubo,
203.

effects of absorption of on lymphatic
glands, 199, 200, 202, and treat-
ment of, 202-3.
how absorbed without inflaming

lymphatic glands, 248.
POLLI, Dr., on deferred coagulation of

the blood, 69.

Polypi of blood in the heart, 23-24, 37.
structure of by MALPIGHI, xxvi.
supposed to be formed of coagulated

serum, xxvi.
COLLINS on, xxvii.
PETIT on the disposition of the

lymphatic and red parts of, xxx.
Mr. PAGET on, 24.
of fibrine, formation of, 23-4, 163-4.
Pores, hypothetical account of, in serous

membranes, 194.
Porpoise, size of the red corpuscles of the

blood, 218. See Corpuscles.
Portal vein, on the blood of the, 269.
Portrait of HEWSON noticed, xix.
PRATER, Mr., on the effect of heat on

coagulation of blood, 4, 27.
on the effects of salts on coagulation
of blood and contraction of muscle,
12-13.

on the effect of agitation on the co-
agulation of the blood, 16.
on the effect of serum on the coagu-
lation of the blood, 44.
Pregnancy, bufly blood during, 40, 41, 48.
lymphatic vessels of the womb en-
larged during, 131.

352

GENERAL INDEX.

PREVOST entertained the hypothesis that
the fibres of fibrin are formed of
colourless nuclei of the red cor-
puscles of the blood, xlii.
PRIESTLEY, Dr., on the effects of oxygen
and of some gases on the colour of
the blood, 8. See Blood,
his discovery of oxygen, 11.
Primitive cells, their agency in absorption,
nutrition, growth, and secretion,
179.

PRINGLE, Sir JOHN, HEWSON'S friend, xv.
gave HEWSON a letter to the Pro-
fessors at Edinburgh, xv.
signed HEWSON'S certificate for the

Royal Society, xvi.
examined the second edition of HEW-
SON'S work on the blood before it
was printed, xxiv.

on the buffy coat of the blood, xxxiv.
referred to on white serum, 83.
case by, 162-3

Protein, bi-oxyde and tri-oxyde of, 81.
PURKINJE, his researches on cells referred

to, 170.

Pus, Dr. HUNTER'S description of its ex-
istence in inflamed parts without
ulceration, xxxvii.
formed without ulceration, 162, 164,

168.

a secretion, 162, 164-5.
supposed action of on the solids, 165.
supposed to be formed from coagu-

lable lymph, 165.
not so putrescent as some other

juices, 165.

sometimes absorbed, 171.
form of the corpuscles of, in the

camelidae, 253.

size of the globules of, see Measure-
ments.

Putrefaction, pus not much prone to, 165.
effect of on the red corpuscles of the

blood, 225, 226.

the blood-corpuscles supposed to be
more prone to, than the rest of the
blood, 227.

Putridity said not to occur in the blood
before its coagulation, 12, 69.

QUATREFAGES, DE, on the colourless
blood of the amphioxus, 273.

QUEKETT, Mr. JOHN, possesses an en-
graving of HEWSON, xix.
on the contents of the red corpuscles

of the blood, 223.

on particles detached from the blood-
discs, 225.

QUESNAY on the buffy coat of the blood,
xxvii, xxxi.

QUESNAY, (continued.}

on the excess of the matter of the
buffy coat in the blood in inflam-
mation, and the formation of that
matter at the expense of the red
corpuscles, xxxi, xxxii, xli, 2 ; from
the action of the arteries, xxxi,

on the parts of the blood, xxxi,

on the effects of whipping the blood,
xxxi.

on the coagulation of the blood, xxxi,
xxxix, xl.

his hypothesis that the buffy coat of
the blood is formed by a trans-
formation of the red corpuscles, xli.

on the effect of vascular action on
the blood, 44.

on white or chylous blood or serum, 85.

Rabbit, red corpuscles in the thoracic

duct of, 277.
RASPAIL, M., on the contents of the red

corpuscles of the blood, 223.
Recapitulation of the chief facts on the

properties of the blood, 71.
Receptaculum chyli, comparatively less in
man than in some lower animals,
135.

in the turtle, 148, 155.
in the haddock, 153, 155.
Rectum intestinum, villous coat of, 188.
Red corpuscles and serum of blood, spe-
cific gravity of a mixture of, 73.
REES, Dr., referred to on the power of
endosmose and exosmose of the
blood-corpuscles, 215. .
description by of the colourless part
of the red corpuscle of human
blood, 223.

Remedies for hemorrhage, 57.
Renal glands, reference to observations on

the office of, 255.
Rennet, effects of on serum, 80.
Reptiles, villi of intestines of, 189, 192.
form and size of the red corpuscles

of the blood of, 218-19, 242.
pale corpuscles of the blood of, 243,

253, 254.
ophidian, shape of the red corpuscles

of the blood of, 312.,
sizes of the corpuscles of the blood

and lymph of, see Measurements.
Respiration, brightening of the blood

by, 71. See Blood,
use of fat in, 88. See Fat.
on the source of the carbon exhaled
. in, 235.

service of the thymus in, 280.
Rest, effect of on the coagulation of the
blood, xxxv, 16, 21, 22, 25, 72.

GENERAL INDEX.

353

RETZIUS, on the absence of the spleen

from the myxine, 273.
on the colourless blood of the am-

phioxus, 273.
Rheumatic tumours, gelatinous fluid said

to be found in, 198.

RIGIDITY, after death, from hanging, suf-
focation, drowning, lightning, and
hunting, 20-1, 69. See Muscles.
ROBERTSON, Mr., his case of white

serum, 83.

RODENTS, on the size of the red cor-
puscles of the blood of, 218.
RODIER, referred to, 2.
Rolls or piles of the red corpuscles of the

blood, xlvi, 221, 228.
Ross, Mr. G., on conversion of oily mat-
ter into a protein-compound, 88.
Royal Society, HEWSON elected a fellow

of, xvi.
rule of as to disputes brought before,

xxiii.
award of the COPLEY medal by, to

HEWSON, xxiii-iv, 91.
RUDBECK, on the lymphatic system, 119,

120.
RUDBECK and BARTHOLIN, discovery of

the lymphatic system by, 245.
RUDOLPHI, on filaria frozen and revived

by thawing, 19.

Ruminants, on the size of the red cor-
puscles of the blood of, 218.
in the blood of the smaller species,
the red corpuscles smaller than
the lymph-corpuscles, 254.
RUSH, Dr., on white or chylous blood

or serum, 85. See Serum.
RUSTON, Dr., on HEWSON'S paper on
emphysema, 94. See Emphysema.
RUYSCH, FRED., on the fibrous matter of

the* blood-clot, xxviii.
his pseudo -membrane from blood,

xxviii, xxx.

cited on the valves of the lymphatic
system, 120, 126; on the glomeruli
of the kidney, 190 ; on the pencilli
of arteries, 191 ; on the size of the
lymphatic glands at different ages,
246.

Saint Thomas's and Guy's Hospitals, HEW-
SON a pupil at, xv.
SAISSY,M., on the fluid state of the blood

during hybernation, 52.
Saline medicines, their effect on the blood

in inflammation, 41. See Salts,
efficacy of, in inflammation, 231.
action of, on lymph-corpuscles and

pale cells, 254.

mixed with blood-discs in water to
show the nucleus, 232.

Salmon, the curd of, perhaps converted

into oily matter, 86.

Salts, SENAC on their effect on the coa-
gulation of the blood, xxxiii.
effects of, in preventing the coagu-
lation of the blood, xxxviii.
employed by HEWSON and MULLER
to keep the fibrin liquid, and se-
parate it from the red corpuscles,
xli, xliii.

effects of, on the size of the red cor-
puscles, 9.

effects of, on the colour and coagula-
tion of the blood, 8, 9, 11-13, 71.
effects of, in preventing the clumping
of the red corpuscles in inflam-
mation, 71. See Buffy Coat,
solutions of, not adapted to measure
the specific gravity of fibrin nor of
the corpuscles of the blood, 74.
solutions of scarcely act on the buffy

coat of the blood, 81.
effect of, on the red corpuscles of
the blood, Ixvi, 9, 220, 223, 229-
32, 274-5, 288.

strong and weak solutions of, effects

of, on the shape and size of the

blood-discs, 229-32, 288.

keep the corpuscles apart, 229, 231.

SAUVAGES, confounded coagulable lymph

with serum, xxx.
SCHENCKIUS, referred to on white serum,

83.
SCHERER, on fibrin of arterial and venous

blood, 81.

SCHROSDER VAN DER KOLK, on the heat
most favorable to coagulation of
blood, 4.

on buffy blood, 34.
on the effect of serum on the coagu-
lation of blood, 44.

SCHULTZ, on the relation of lymph-cor-
puscles to the red corpuscles of the
blood, xlvii.

on the effects of some substances on

the red corpuscles of the blood, 9.

on the effect of salt on the colour of

splenic blood, 269.
on the blood of the splenic vein, 269.
on the use of the spleen, 273.
on red corpuscles in the chyle, 277.
SCHWANN, M., his cell-nucleus, andHfiw-
SON'S central particle, xlviii, 254.
formation of the fibrils of fibrin op-
posed to his theory, 14.
ScHWENKE,on the effects of different tem-
peratures on coagulation, 3.
thought the red corpuscles sink or

rise in the blood-clot, 7.
on effects of salts on the blood, 11.
on the buffy coat of the blood, 30.

23

354

GENERAL INDEX.

SCUDAMORE, SirC., on theeffect of warmth
on the coagulation of blood, 4.

on the effect of agitation on coagu-
lation of the blood, 16.

on the effect of electricity on the co-
agulation of the blood, 20.

on effects of cold on coagulation, 18.
Seal, the chyle of, supposed to be absorbed
by veins, 179.

the lacteal system of, 179-80.

size of the blood-discs of, 218.
Secretion of fluid into serous sacs, HEW-
SON'S theory of noticed, xxxix.

pus described as a, 162, 164-5.

of lymph into cavities for their lubri-
cation, 166-7.

agency of cells in, 170, 179.
SENAC, JEAN, observed that the fluidity of
the blood is not caused by its heat,
xxxiii.

on the coagulation of the blood, xxxii-
iv, xxxix-xl.

on the buffy coat of the blood, xxxii.

on the effect of whipping the blood,
xxxii-iv.

on the effect of salts on the coagula-
tion of the blood, xxxiii.

on the effects of air on the state of
the corpuscles and on the colour of
the blood, 7.

supposed that agitation prevents the
coagulation of the blood, 15.

on effects of cold on coagulation, 18.

his case of blood which did not co-
agulate, 68.

referred to on the serosity, 79.

on white or chylous blood or serum, 8 5 .

on the depressions on the surfaces of
the red corpuscles of the blood, 216.

on the brightness and darkness of the
central spot of the blood-corpuscle,
216.

on the shape of the blood-corpuscles,
211.

considered the red corpuscle of the
blood as solid, 220.

disputed LEEUWENHOEK'S view of
the compound nature of the red
corpuscles of the blood, 226.

considered the blood-corpuscles as very
inflammable and putrescent, 227.

on the pliancy of the blood- discs when
circulating in a narrow channel,
228-9.

saw the pale corpuscles in the blood,
282.

cites LEEUWENHOEK as to the solvent
power of ammonia on the blood-
discs, 230.

stated that the splenic blood is bright
red, 269,

Separationof blood promoted by warmth,3,

4. See Heat, Blood, Coagulation,
of serum and crassamentum, 2, 4 ;

heat most favorable to, 71.
Serosity, a term used for serum, xxix, xxx,

xxxiii.
the part of the serum incoagulable

by heat, xxxiv, 39, 79.
Serous membranes, crusts of coagulated

lymph on, 162,164 ; without ulcera-

tion, 162. See Pus, and Ulceration.
hypothetical account of pores in, 194.
Serous sacs, fluid of, LOWER on its coagu-
lation by heat, xxvi.
secretion of fluid into, notice of

HEWSON'S theory of, xxxix.
fluid of, supposed to be mere water,

157; properties of, 158-61.
how the lymph is secreted into them,

166.

absorption of water injected into, 171.
fluid of, compared with that of the

lymphatics, 185. See Fluid,
nature of the fluid of, in dropsies,

196-8.
Serum of the blood, coagulation of, by

heat, xxv-vi ; by spirit of wine and

by sublimate, xxvi.
supposed to form polypi in the heart,

xxvi.

called serosity, xxvii, xxix, xxx, xxxiii.
confounded with lymph by VERDUC,

xxvii; by JURIN, MORGAN, and

NORTHCOTE, XXix.

said by LISTER to jelly on standing,
xxix.

supposed to be changed into the buffy
coat, xxx.

specific gravity of, xxxv, 78.

discovery of the incoagulable part of,
or serosity, xliv, 79. •

separation of, from blood-clot, 1-4.

proportion of, in different cases, 1.

specific gravity of, diminished in the
blood last flowing, 2.

coagulation of, promoted by Glauber's
salt, 5-6, 28.

coagulates at a lower heat when the
albumen is in excess, 6.

and coagulable lymph have been con-
founded, xxvii, xxix, xxx, 6, 30.

salts of, said to be the cause of the
bright colour of arterial blood, 8.

mixtures of, with other serum, coagu-
lating spontaneously, 21, 31, 158,
196, 235.

heat required to coagulate it, 27-8,78;
differs in different animals, 28.

effects of water, salts, and acids on
its coagulating point, 28.

not made turbid bv manv acids, 31.

GENERAL INDEX.

355

Serum, (continued.')

in the huffy coat of the blood, 32, 41.

red corpuscles sink slower in, than
in blood, 37.

consistency and specific gravity of, in
buffy blood, 38.

consistency and specific gravity of the
serum separating at different times
from the same clot, 38-9.

of lower specific gravity than coagu-
lated lymph, 40.

paces of sinking in it of the corpuscles
of buffy blood, 41.

effect of, on the coagulation of the
blood, 44.

and crassamentum, heat most fa-
vorable to the separation of, 71.

and fibrin, coagulation of, 78-9.

how differing from coagulable lymph,
6, 30, 78-80.

properties of, 78-9.

inspissation of, by evaporation, 79-80.

its coagulable matter termed muci-
lage, 78-80, 232.

effect of rennet on, 80.

when diluted, requires more heat to
coagulate it, 28, 80.

and milk, effects of boiling and of
rennet on, compared, 80-1.

white, or milk-like, account of, 78, 82;
microscopic examination of, 82 ;
instances of, from authors, 83 ;
cases of, in geese, 84, 89; the
white matter fatty, 85 ; found
on the surface of arterial and ve-
nous blood, 85 ; owing to chyle,
85, 87 ; another kind of white se-
rum in disease, 85-6, 173 ; specific
gravity of, 38, 86 ; supposed to be
owing to the absorption of fatty
matter from its cells, 86 ; supposed
to be caused by absorption of oil,
86-9.

of horse's blood, causes a clumping
among the red corpuscles of an-
other animal, 215.

used to dilute the blood in examining
the red corpuscles, 215, 219.

its effect, when beginning to putrefy,
on the red corpuscles of the blood,
225.

preserves the flatness of the blood-
discs by its salts, 229.

green in a caterpillar, 234.

mixtures of varieties of, fibrin formed
in, 235. See Fibrin, and Coagula-
tion of Serum.
Serum of serous sacs, see Fluid, and Serous

Sacs.
Sharks, blood-corpuscles of, 234.

SHARPEY, Dr., on Dr. GORDON'S account
of serum and fibrin of the blood,
xliii.
Sheep, coagulation of the blood of, 24.

coagulation of blood flowing from
slaughtered, 46-7, 57.

struggles of one dying, seemed to
alter the blood, 76.

villi of intestines of, 187.
SHELDON, Mr., a lecturer on anatomy at
Windmill-street, xvi.

his commendation of HEWSON'S in-
quiries on the lymphatic system of
oviparous vertebrata, xxiv.

on the contraction of lymphatic ves-
sels, 126.

on the beginning of the lacteals in

the villi, 181.

Shrimp, blood-corpuscles of the, 234.
Skates, blood-corpuscles of, 234.
SIDDALL, Mr., on the coagulation of the

splenic blood, 269.

SIMMONS, Dr. SAMUEL FOART, his life
of Dr. HUNTER referred to, xiii.

as to the claim of priority between
FORDYCE and HEWSON on the
formation of the buffy coat, xxxviii.
SIMON, Dr., on the transformation of the
red corpuscles into fibrin, xxviii,
xxxi, 2.

on the relation of lymph-corpuscles
to the red corpuscles of the blood,
xlvii.

on increase of fibrin and decrease of
red corpuscles in blood during in-
flammation, 2.

on the effects of salts on coagulation
of the blood, 13.

on the blood of the horse, 40.

on the source of carbon exhaled from
the lungs, 235.

on the office of the red corpuscles of
the blood, 235-6.

on the blood of the portal vein, 269.

on red corpuscles in the thoracic
duct of the rabbit and horse, 277.

on the absence of pale corpuscles
from the blood of the spleen, 283.
SIMON, Mr., considers the globules of the
thymus fluid as nuclei, 254.

referred to on the structure of the
tbymus, 257 ; and on its develop-
ment, 263.

on the use of the thymus, 280.
SIMSON, Dr., on the production of the
buffy coat of the blood by a liga-
ture on the limb, 65, 67.
Sinking of the red corpuscles produces the
buffy coat of the blood, 57. See
Corpuscles, and Buffy Coat.

356

GENERAL INDEX.

Size, or inflammatory crust, formation of,

30, see Buffy Coat.
Skin, villi or papillae of, 193.
Sloth, large size of the red corpuscles

of its blood, 218. See Corpuscles.
Slough, the term applied hy Dr. HUNTER

to coagulated lymph on inflamed

serous membranes, xxxvii.
Slow-worm, blood-discs of a" narrower

ellipse than those of its congeners,

312. See Corpuscles.

SMITH, Dr. HUGH, attended on physic

by HEWSON, xv.
his knowledge of the three parts of

the blood, xxxvi.
SMITH, Dr. ANDREW, on the coagulation

of the blood of hunted antelopes,

21.

SMITH, Dr. JAMES CARMICHAEL, 88.
Snake, its blood-discs differ in shape from

those of the slow-worm, 312.
Snowy owl, its blood-discs a narrower

ellipse than those of its congeners,

313. See Corpuscles, red, of the
blood.

Softening of fibrin, 24.
SONNERAT, on fishes in hot springs, 27.
Specific gravity of the serum of blood,
xxxv, 2, 78. See Serum.

of the crassamentum, xxxv.

of the buffy coat of the blood, xxxv,
73-4.

of the red corpuscles, xxxv, 73-4.

of the fluid of a hydrocele, 73.

of different parts of the blood, 73-4.

of some parts incorrectly inferred
by immersion in saline solutions,
73-4.

of serum of buffy blood, 38.
SPIGELIUS, referred to on the spleen,

265, 267.

Spirit of wine, BOYLE noticed that it co-
agulates serum, xxvi.
Spirit, nitro-aerial, MAYOW'S, 7, 11.
Spleen, HEWSON'S lecture on the use of
the, xvii.

first publication of HEWSON'S views
as to the use of, xxiv.

lymphatic vessels of, and their con-
tents and use of, notice of HEW-
SON'S observations on, xlvii.

lymphatic glands, and thymus, 121,
127.

and pancreas, lymphatics of, 133.

kidneys, and liver, lymphatics of,
133-4.

on its situation and structure, 264-8.

speculations on its use, 264, 284.

sometimes several spleens, 265.

on the size and weight of the, 265-6.

Spleen, (contimied.)
colour of, 266-7.
softness of, when putrefied, 267.
cells of, 267-8, 270.
properties of the blood of, 269, 283,

289.

lymphatic vessels of, 269-71 ; fluid
of these lymphatics, 271-2, 276,
289 ; red particles in it, xlvii, 272.
office of, 273, 275.
cases in which it was cut out with-
out any ill effect, 275.
• several spleens in a sturgeon, 273.
its concern in the formation of the

red corpuscles of the blood, 275.
envelopes of the red corpuscles of
the blood supposed to be formed
by, 282-6, 289.
absent in some of the lowest fishes,

273, 283.

pale corpuscles in the blood of, 283.
its lymphatics considered as its ex-
cretory ducts, 281, 283, 289.
nuclei in the red corpuscles of the

blood of, in a goose, 283.
red and pale corpuscles of the blood
of, compared with those from the
heart, 283.

arguments as to its use from the ex-
tirpation of, 284-5, 289-90.
red colour of the lymph of, 276,

289.
considered as an appendage to the

lymphatic vessels, 289-90.
Splenic lymph, red corpuscles in, xlvii.
Splenic blood, clots in, 69. See Spleen.
Spot, central, of the red blood-corpuscles,

216. See Corpuscles, red.
Springs, hot, fishes living in, 27.
SPROEGEL on the effects of air on the

coagulation of the blood, 19.
Stagnation darkens the blood, 66.
Stanley musk-deer, its minute red blood-
corpuscles, 219. See Musk Deer.
STARK, Dr., 297, 301.

on the nutritious qualities of fat, 87-

88.

notice of him and his works, 87-88.
on HEWSON'S paper on emphysema,

94.
STEVENS, Dr., on the colour of the blood,

8,9.

STEVENSON, Miss, HEWSON'S first ac-
quaintance and marriage with, xiv.
her marriage to HEWSON, xiv, xvi,

xx.

notice of her, xx.
MARGARET, Mrs. HEWSON'S mother,

xx.
STOKER, Dr., on buffy blood, 34.

GENERAL INDEX.

357

Stomach, state of the blood and muscles

in an animal killed by a blow on, 21.

lymphatics of, 133-4 ; supposed to

end in its veins, 134.
lymphatic glands of, 137.
structure of the inner coat of, 188.
Strength of an animal, reduction of, pro-
motes the coagulation of the blood,
75- 7. See Coagulation,
effects of temporary exertions of, in
the blood-vessels, on the properties
of the blood, 77. See Coagulation.
Struggles of a dying animal, effects of on
the coagulation of the blood, 76.
Sublimate, BOYLE noticed that it coagu-
lates serum, xxvi. See Serum.
Suffocation, effect of on the coagulation
of the blood, 68, 69 ; and on the
stiffening of muscles, 69.
Sugar, brightens the blood-clot, 8.

effects of on the red corpuscles, 9.
Sussex, HEWSON'S visit to, xvi.
SWIETEN, see VAN SWIETEN.
SYDENHAM, THOMAS, on the buffy coat of

the blood, xxvii, xxxii, xli, 2.
supposed the red corpuscles of the
blood to be transformed into the
buffy coat, xxxii.

entertained the hypothesis that the
buffy coat of the blood is formed
of the colourless part of the red
corpuscles, xli.

on effect of cold on coagulation, 17.
prevented the formation of the buffy

coat by stirring the blood, 33.
on the absence of a buffy coat when
the blood trickles away from the
vein, 60.
System, lymphatic, see Lymphatic.

Tables of Measurements of the sizes of

the corpuscles of blood, lymph,

chyle, and pus, see Measurements.

TAYLOR, Dr., note by, from Dr. MONRO'S

lectures on lymphatics, 103.
Temperature, see Heat, Cold, Freezing.

that most favorable to the separa-
tion of the crassamentum and se-
rum, 71,

animal, supposed connexion of the
thymus with, 280. See Thymus.

effects of on a fluid mixture of blood

and salt, 82. See Coagulation.
THACKRAH, Mr., on increase of fibrin in
the blood in inflammation, 2.

on the effects of warmth on the co-
agulation of the blood, 4.

notice of scarlet venous blood by, 10.

on the effect of agitation on the co-
agulation of the blood, 16.

THACKRAH, (continued.)

on the effects of cold and of freezing
on coagulation of blood, 18, 19.

on the effect of air on coagulation, 20.

on coagulation of blood in living and
dead veins, 23.

on coagulation of the blood as to time
in different animals, 24.

on the fibrin and serum of buffy
blood, 38.

on blood from different vessels, 44.

on the coagulation of blood from
slaughtered animals, 47.

on white or chylous serum, 85.

on the coagulation of the blood of the

portal vein, 269.
Thawing, effects of on frozen blood, 19.

and freezing the blood, effects of on
its coagulation, 2 1,25, 26. See Co-
agulation, Heat, Cold, &c.
Thigh and leg, lymphatics of, 128.
Thinning of the blood or lymph from

strong vascular action, 76.
THOMSON, Dr. ALLEN, on the separation
of the corpuscles and fibrin in the
blood of the horse, 40.

Dr. R. D., on white serum, 86.
Thoracic duct, PECQUET on, 119.

EUSTACHIUS on, 120.

its situation and termination, 123.

coats of, 124.

description of in the human subject,
134-6 ; red blood-clot in it, 277.

of the horse, ruddy colour of contents
of, 276, from red corpuscles in,
276-7.

red corpuscles in, in the rabbit, 277.

two of them in birds, 144-5.

two in the turtle, 148.

double in the haddock, 153-4.
Thymus gland, first publication of HEWT-
SON'S views as to the use of, xvii,
xxiv.

notice of HEWSON'S observations on
its lymphatic vessels, and on the
corpuscles in the fluid of, xlvi-vii.

lymphatic glands, and spleen, 12 1,1 2 7.

structure of the globules in the fluid
of the, 253-4 ; considered as nuclei
or immature cells, 254. See Cor-
puscles.

their chemical properties, 253 ; in
which they differ from the red cor-
puscles of the blood, 254.

size of the corpuscles of, see Measure-
ments.

the microscopical and chemical cha-
racters of the corpuscles, 259.

ontheusesof,260,261,263;included
in the theory of fat-formation, 280.

3.r>8

GENERAL INDEX.

Thymus gland, (continued.)

its concern in the formation of the
blood-corpuscles, 275.

reason for its large size in early life,
279.

considered as an appendage to the
lymphatic system, 279-80, 289.

the membrane lining its cells, 280-1.

its lymphatic vessels carry a fluid
like that in the gland, and are
considered as its excretory ducts,
xlvi-vii, 260-1, 281; importance
of examining their contents in in-
quiries as to its office, 259, 281.

microscopical examination of the fluid
of its lymphatic vessels, 259.

corpuscles in the fluid of its lymph-
atic vessels, 259.

on the question of the passage of
corpuscles into its lymphatics,
280-1.

fluid of, differs only from that of the
lymphatic glands in containing
more corpuscles, 281.

concern of in nutrition, 281.

fluid in the cells of similar to that in
its lymphatic vessels, 260.

diminished in diseased, ill-fed, and
over-worked animals, 261-2.

increases in size after birth in healthy
animals, but diminishes in ill-
nourished ones, 246, 261-2.

its size and weight at different pe-
riods of life and in different sexes,
261-3.

on its situation and structure, 255-8,
260-1.

compared in structure and office to a
lymphatic gland, 279.

experiments to find out its excretory
ducts, 258-9.

lymph-corpuscles formed in, 286.
Thyroid gland, lymphatics of, 140, 143.
TICKELL, Mrs., aunt to Mrs. HEWSON, xx.
TIEDEMANN, noticed the difference be-
tween blood-corpuscles and the
globules of the tissues, xliii.

on the passage by veins of the chyle
in the seal, 179.

on the coagulation of the blood of the
splenic vein, 269.

on the use of the spleen, 273.
Tongue, papillae of, 193.
Torpid animals, coagulation of the blood

in, 52.

TORRE, Father DELLA, see BELLA TORRE.
TOYNBEE, Mr., on nourishment of tissues

without blood-vessels, 179.
TRAILL, Dr. on the serum of buflyblood, 38.

on white serum, 85,86.

Transudation, lymph in the serous sacs

supposed to be a, 166.
of theblood through the vessels, 166-7.
of the bile, 166-7, 169, 173.
supposed not to take place through

membranes during life, 168-9.
through fresh and stale membranes

compared, 169, 173.
Tubercle, seat of in consumption of the

lungs, 138.

TULPIUS, referred to on white serum, 83.
Tumours, blood remaining long fluid in, 70.
Turbot, villi of the intestines of, 189.
TURNER, Dr., on the colour of arterial

blood, 8.
Turtle, description of the lymphatic system

in, 147.

villi of the intestines of, 189.
lymphatic glands wanting in, 250.
description of the lacteals in, 250.
formation of the lymph-corpuscles in

the lymphatics of, 278.
TURTON, T., signs HEWSON'S certificate
for the Royal Society, xvi.

Ulceration, pus observed independently of,
by Dr. HUNTER, xxxvii. See Pus.
pus formed without, 162, 164.
agency of cells in, 179.
independently of vessels, 179.
Urea, conjectured to be aproduct of changes

in the blood-corpuscles, 236.
Uric acid, conjectured to be a product of
changes in the blood-corpuscles,
236.

Uterus, mol§s or false conceptions in, 25.
lymphatic vessels of, enlarged during
pregnancy, 131.

Vacuum, effects of a, on the coagulation

of the blood, 20. See Coagulation.
VALENTIN, Professor, on molecules form-
ing the envelope of the red cor-
puscle of the blood, 225.
Valves of the lymphatics, RUYSCH on, 120.
of the lymphatic system, 126.
of the lymphatic vessels, imperfect or

absent in fish, 155.
use of those of the lymphatics, 195.
VAN DER KOLK, see SCHROZDER.
VAN SWIETEN, on the coagulation of the

blood, xxix.
Vasa lymphatica, 123. See Lymphatic

Vessels.

Vascular action, QUESNAY'S veiw of the
effect of in the formation of the
buffy part of the blood, xxxi.
its effect on the blood, 44-6, 48.
effect of on the coagulation of the
blood, 53-5,65,68. See Coagulation.

GENERAL INDEX.

359

Vascular action, (continued.)

connexion of with the buffy coat of the

blood, 55-7, 6 1,65. See Buffy Coat.

its effect onthepropertiesof the blood,

72, 74, 75.
when strong, said to thin the lymph

and retard its coagulation, 76.
Veins of living animals, coagulation of
blood in, at different heats, 4,
26, 51. See Coagulation,
coagulation of blood confined in, in

the body, 16, 21-3.
whether they do the office of absorp-
tion, 171-2. See Absorption,
supposed formerly to absorb both

chyle and lymph, 172.
obstruction of by coagulated blood,

connected with oedema, 174-5.
arguments for absorption by, 177.
instances of absorption without them,

179.

on absorption by, 180.
lymphatics supposed to be veins, 186.
question of absorption by, 199.
Veins, mesenteric, see Mesenteric Veins.
Vena cava, dropsy produced by a liga-
ture on, 174. See Dropsy,
portae, on the blood of the, 269.
Venous and arterial blood, colour of,

7, 8, 10. See Blood,
blood, sometimes scarlet, 10, 71.
Venereal bubo, glands in which it is
seated, 129. See Lymphatic Glands,
poison, sometimes enters the consti-
tution without causing a bubo, 203.
sore, excision of recommended, 203.
Vera Cruz, HEWSON'S eldest son died

at, xxi.

VERDUC, JOHN BABTIST, on the coagula-
tion of the blood, xxvii.
called the serum serosity, xxvii.
used the term mucilage for the self-
coagulating part of the blood, 232.
VERHEYEN, PHILIP, on the coagulation

of the blood, xxix.
VERSCHUIR, Dr., on irritability in the

coats of the blood-vessels, 124.
Vertebrata, discovery of the paleness of
the blood in young embryos of,
xliv-v, 222. See Blood,
have red blood-corpuscles, 211 ; ex-
cept the amphioxus, 234.
corpuscles of the lymph of, 212.
paleness in the blood of very young
embryos of, 222 ; and abundance of
pale corpuscles in, 222.
oviparous, see Oviparous Vertebrata.
sizes of the corpuscles of blood,
lymph, chyle, and pus in, see Mea-
surements.

Vesicle of the red corpuscle of the blood,

nucleus within the, how seen like

a pea in a bladder, 274.
effect of water on, and neutral salts

on, 274-5.
adhesion between the vesicle and

nucleus, 275.
red, of the blood-corpuscle, see

Envelope ; and Corpuscles, red, of

blood.

Vessels, lymphatic, see Lymphatic Vessels.

Villi of the intestines of the cod-fish, 155.

supposed open orifices of the lacteals

in, 181, 189, 193, 194.
loops or closed ends of lacteals in,

181.
ampullulae in the intestinal villi, 181,

187, 189-91.
intestinal, on the structure of, 187-

92 ; transitions in the form of, 187-
intestinal, in the turbot and turtle,

189.

intestinal, in birds, 189, 192
HEWSON'S preparations of, 189.
of the oesophagus, 188.
of the true skin, 193.
Viper, embryo, blood-corpuscles of, larger

and rounder than those of the

mother, 233. See Reptiles, and

Corpuscles.
Viscidity of the blood increased by cold,

50-2, see Cold ; and by faintness,

57, see Coagulation of the Blood,
of the red corpuscles of the blood,

221. See Corpuscles.
Viverras, size of the red corpuscles of the

blood of, 218. See Corpuscles.

WAGNER, Professor, states the belief on

the Continent that the coagulation

of the blood is produced by the

red corpuscles, xliii.
on the relation of lymph-corpuscles

to the red corpuscles of the blood,

xlvii.
on the shape of the intestinal villi at

different periods of life, 187.
on the blood-corpuscles of amphibia,

219.
referred to on the blood-corpuscles

of fishes, 234.
on the blood-discs as glandular cells,

235.

on the formation of the red cor-
puscles of the blood from the pale

ones, 254.
Warmth, effects of on coagulation, 51.

See Heat, and Coagulation.
Water, effect of on the red corpuscles of

the blood, xlvi, 9, 21 5, 220-4, 274,

288. See Corpuscles.

360

GENERAL INDEX.

Water, (continued.')

added to a fluid mixture of blood

and salts or other matters, makes

it coagulate, 6, 12. See Coagulation.

effect of on the coagulation of the

blood, 44.

absorption of when injected into the
serous sacs and beneath the skin,
171.
affects the blood-discs of the same

animal differently, 232-3.
nucleus of the blood-disc of ovi-
parous vertebrata not soluble in,
253.

action of on lymph-globules, 254.
WATSON, Dr., on the council which
awarded the COPLEY medal to
HEWSON, xxiii.

referred to on white serum, 83.
WATSON, Mr., xiii.

Weak animals, coagulation of the blood
hastened in, 161. See Coagula-
tion,
coagulation of lymph retarded in,

161. See Lymph,
modification of the fluid of the serous

sacs in, 197. See Fluid.
Weakness disposes the blood to coagu-
late, 75-7. See Coagulation.
Weasels, size of the red blood-corpuscles

of, 218. See Corpuscles.
WELLS, Dr., on the colour of the blood, 9.
WEST, Mr., President of the Royal So-
ciety, on its conduct in disputes
before, xxiii.

his address on giving the COPLEY
medal to HEWSON, xxiii.

Whale, size of the red corpuscles of the

blood of the, 2 1 8. See Corpuscles.
Whipping, on the separation cf fibrin from

the blood by, xxviii, xxx-ii. See

Fibrin, and Coagulation.
White serum composed of fatty matter, 85.
found on the surface of arterial and

venous blood, 85. See Serum.
Whiting and cod, lymphatic system of,

154.
WiLLiAMS,Dr.C.J. B.,onbuffyblood,41.

on the colour of the blood, 9.
WILLIS, Dr., on the crassamentum and

serum, xxvi.
WILSON, Mr., on the three parts of the

blood, xlii.

Windmill street, eminent lecturers on ana-
tomy there, xvi.
Womb, lymphatic vessels of enlarged

during pregnancy, 131.
Wound of the lymphatics, and nature of

the fluid flowing from, 198.
treatment of, 199.
Wound of the lungs, 291.

experiments concerning, 295.

not always existing when air escapes

from the chest, 229.
WURTZ on preparing a soluble albumen,

31.
WYNPRESSE, Dr., his Latin edition of

HEWSON'S works referred to, xiii.

YARRELL, Mr., the colourless blood of his

amphioxus, 234, 273.
YOUNG, Dr., observed that water does

not dissolve the red corpuscles of

the%lood, 215.

THE END.

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