A
COMPENDIOUS SYSTEM
OF
ANATOMY.
IN SIX PARTS.
PART I. OSTEOLOGY.
II. OF THE MUSCLES,
ETC.
III. OF THE ABDOMEN.
PART. IV. OF THE THORAX.
V. OF THE BRAIN
AND NERVES.
VI. OF THE SENSES.
ILLUSTRATED WITH TWELVE LARGE COPPERPLATES.
EXTRACTED FROM THE AMERICAN EDITION
OF THE ENCYCLOPÆDIA.
NOW PUBLISHING,
BY THOMAS DOBSON, AT THE STONE HOUSE, N° 41,
SECOND STREET, PHILADELPHIA.
MDCCXII. 

 

A
SYSTEM
OF
ANATOMY.
ANATOMY is the art of dissecting, or arti-
ficially separating and taking to pieces, the
different parts of the human body, in order to an
exact discovery of their situation, structure and
œconomy. The word is Greek, ανατομη; derived
from αγατεμγω, to dissect, or separate by cutting.
INTRODUCTION.
§ I. History of Anatomy.
This art seems to have been very ancient;
though, for a long time, known only in an im-
perfect manner.—The first men who lived must
A2 have 

4 INTRODUCTION.
have soon acquired some notions of the structure
of their own bodies, particularly of the external
parts, and of some even of the internal, such as
bones, joints, and sinews, which are exposed
to the examination of the senses in living bodies.
This rude knowledge must have been gradu-
ally improved, by the accidents to which the
body is exposed, by the necessities of life, and
by the various customs, ceremonies, and super-
stitions, of different nations. Thus, the observ-
ance of bodies killed by violence, attention to
wounded men, and to many diseases, the vari-
ous ways of putting criminals to death, the fune-
ral ceremonies, and a variety of such things, must
have shown men every day more and more of
themselves; especially as curiosity and self-love
would here urge them powerfully to observation
and reflection.
The brute-creation having such an affinity to
man in outward form, motions, senses, and ways
of life; the generation of the species, and the
effect of death upon the body, being observed
to be so nearly the same in both; the conclusion
was not only obvious, but unavoidable, that their
bodies were formed nearly upon the same model.
And the opportunities of examining the bodies
of brutes were so easily procured, indeed so ne-
cessarily occurred in the common business of
life, that the huntsman in making use of his
prey, the priest in sacrificing, the augur in di-
vination, and, above all, the butcher, or those
who

5 INTRODUCTION.  
who might out of curiosity attend upon his ope-
rations, must have been daily adding to the little
stock of anatomical knowledge. Accordingly
we find, in fact, that the South-sea-islanders, who
have been left to their own observation and rea-
soning, without the assistance of letters, have
yet a considerable share of rude or wild anatomi-
cal and physiological knowledge. Dr Hunter
informs us, that when Omai was in his museum
with Mr Banks, though he could not explain
himself intelligibly, they plainly saw that he
knew the principal parts of the body, and some-
thing likewise of their uses; and manifested a
great curiosity or desire of having the functions
of the internal parts of the body explained to
him; particularly the relative functions of the
two sexes, which with him seemed to be the most
interesting object of the human mind.
We may further imagine, that the Philoso-
phers of the most early ages, that is, the men
of curiosity, observation, experience and reflec-
tion, could not overlook an instance of natural
organization, which was so interesting, and at the
same time so wonderful, more especially such of
them as applied to the study and cure of diseases.
We know that physic was a branch of philoso-
phy till the age of Hippocrates.
Thus the art must have been circumstanced in
its beginning. We shall next see from the tes-
timony of historians and other writers, how it
actually appeared as an art, from the time that
writing

6 INTRODUCTION.
writing was introduced among men; how it was
improved and conveyed down to us through a
long series of ages.
Civilization, and improvements of every kind,
would naturally begin in fertile countries and
healthful climates, where there would be leisure
for reflection, and an appetite for amusement.
Accordingly, writing, and many other useful
and ornamental inventions and arts, appear to
have been cultivated in the eastern parts of Asia
long before the earliest times that are treated of
by the Greek or other European writers; and
that the arts and learning of those eastern people
were in subsequent times gradually communi-
cated to adjacent countries, especially by the me-
dium of traffic. The customs, superstitions, and
climate of eastern countries, however, appear to
have been as unfavorable to practical anatomy,
as they were inviting to the study of astronomy,
geometry, poetry, and all the softer arts of peace.
Animal bodies there, run so quickly into nau-
seous putrefaction, that the early inhabitants must
have avoided such offensive employments, as ana-
tomical inquiries, like their posterity at this day.
And, in fact, it does not appear, by the writ-
ings of the Grecians, or Jews, or Phœnicians,
or of other eastern countries, that anatomy was
particularly cultivated by any of those eastern na-
tions. In tracing it backwards to its infancy, we
cannot go farther into antiquity than the times
of the Grecian philosophers. As an art in the
state 

7 INTRODUCTION.  
state of some cultivation, it may be said to have
been brought forth and bred up among them as
a branch of natural knowledge.
The æra of philosophy, as it was called, be-
gan with Thales the Milesian being declared by
a very general consent of the people, the most
wise of all the Grecians, 480 years before Christ.
The philosophers of his school, which was called
the Ionian, cultivated principally natural know-
ledge. Socrates, the seventh in succession of their
great teachers, introduced the study of morals,
and was thence said to bring down philosophy
from heaven, to make men truly wise and hap-
py.
In the writings of his scholar and successor
Plato, we see that the philosophers had carefully
considered the human body, both in its organi-
zation and functions; and though they had not
arrived at the knowledge of the more minute and
intricate parts, which required the successive la-
bour and attention of many ages, they had made
up very noble and comprehensive ideas of the
subject in general. The anatomical descriptions
of Xenophon and Plato have had the honour of
being quoted by Longinus (§ xxxii.) as speci-
mens of sublime writing: and the extract from
Plato is still more remarkable for its containing
the rudiments of the circulation of the blood.
"The heart (says Plato) is the centre or knot of
the blood-vessels; the spring or fountain of the
blood which is carried impetuously round; the
blood 

8 INTRODUCTION.
blood is the pabulum or food of the flesh; and,
for the purpose of nourishment, the body is laid
out into canals, like those which are drawn
through gardens, that the blood maybe conveyed,
as from a fountain, to every part of the pervious
body."
Hippocrates was nearly contemporary with the
great philosophers of whom we have been speak-
ing, about 400 years before the Christian æra.
He is said to have separated the profession of
philosophy and physic, and to have been the first
who applied to physic alone as the business of
his life. He is likewise generally supposed to be
the first who wrote upon anatomy. We know
of nothing that was written expressly upon the
subject before; and the first anatomical dissection
which has been recorded, was made by his friend
Democritus of Abdera.
If, however, we read the works of Hippo-
crates with impartiality, and apply his accounts
of the parts to what we now know of the human
body, we must allow his descriptions to be im-
perfect, incorrect, sometimes extravagant, and
often unintelligible, that of the bones only ex-
cepted. He seems to have studied these with
more success than the other parts, and tells us
that he had an opportunity of seeing a human
skeleton.
From Hippocrates to Galen, who flourished
towards the end of the second century, in the
decline of the Roman empire, that is, in the
space 

9 INTRODUCTION.
space of 600 years, anatomy was greatly im-
proved; the philosophers still considering it as a
most curious and interesting branch of natural
knowledge, and the physicians, as a principal
foundation of their art. Both of them, in that
interval of time, contributed daily to the com-
mon stock, by more accurate and extended ob-
servations, and by the lights of improving philo-
sophy.
As these two great men had applied very par-
ticularly to the study of animal bodies, they not
only made great improvements, especially in
physiology, but raised the credit of natural
knowledge, and spread it as wide as Alexander's
empire.
Few of Aristotle's writings were made public
in his lifetime. He affected to say that they
would be unintelligible to those who had not
heard them explained at his lectures: and, ex-
cept the use which Theophrastus made of them,
they were lost to the public for above 130 years
after the death of Theophrastus; and last came
out defective from bad preservation, and corrupt-
ed by men, who, without proper qualifications,
presumed to correct and supply what was lost.
From the time of Theophrastus, the study of
natural knowledge at Athens was forever on the
decline; and the reputation of the Lycæum and
Academy was almost confined to the studies
which are subservient to oratory and public
speaking.
The 

10 INTRODUCTION.
The other great institution for Grecian edu-
cation, was at Alexandria in Egypt. The first
Ptolemies, both from their love of literature,
and to give true and permanent dignity to their
empire, and to Alexander's favorite city, set up
a grand school in the palace itself, with a museum
and library, which, we may say, has been the
most famed in the world. Anatomy, among
other sciences, was publicly taught; and the two
distinguished anatomists were Erasistratus the pu-
pil and friend of Theophrastus, and Herophilus.
Their voluminous works are all lost; but they
are quoted by Galen almost in every page. These
professors were probably the first who were au-
thorized to dissect human bodies; a peculiarity
which marks strongly the philosophical magnani-
mity of the first Ptolemy, and fixes a great æra
in the history of anatomy. And it was, no doubt,
from this particular advantage which the Alex-
andrians had above all others, that their school
not only gained, but for many centuries pre-
served, the first reputation for medical education.
Ammianus Marcellinus, who lived about 650
years after the schools were set up, says, they were
so famous in his time, that it was enough to se-
cure credit to any physician, if he could say he
had studied at Alexandria.
Herophilus has been said to have anatomized
700 bodies. We must allow for exaggeration.
Nay, it was said, that both he and Erasistratus
made it a common practice to open living bodies,
that 

11 INTRODUCTION.
that they might discover the more secret springs
of life. But this, no doubt, was only a vulgar
opinion, rising from the prejudices of mankind;
and accordingly, without any good reason, such
tales have been told of modern anatomists, and
have been believed by the vulgar.
Among the Romans, though it is probable they
had physicians and surgeons from the founda-
tion of the city, yet we have no account of any
of these applying themselves to anatomy for a
very long time. Archagathus was the first
Greek physician established in Rome, and he was
banished the city on account of the severity of
his operations.—Asclepiades, who flourished in
Rome 101 years after Archagathus, in the time
of Pompey, attained such a high reputation as
to be ranked in the same class with Hippocrates.
He seemed to have some notion of the air in res-
piration acting by its weight; and in accounting
for digestion, he supposed the food to be no far-
ther changed than by a comminution into ex-
tremely small parts, which being distributed to
the several parts of the body, is assimilated to the
nature of each. One Cassius, commonly thought
to be a disciple of Asclepiades, accounted for the
right side of the body becoming paralytic on
hurting the left side of the brain, in the same
manner as has been done by the moderns, viz.
by the crossing of the nerves from the right to
the left side of the brain.
From the time of Asclepiades to the second
century,

12 INTRODUCTION.
century, physicians seem to have been greatly
encouraged at Rome; and, in the writings of
Celsus, Rufus, Pliny, Cœlius, Aurelianus, and
Aræteus, we find several anatomical observations,
but mostly very superficial and inaccurate. To-
wards the end of the second century lived Clau-
dius Gallenus Pergamus, whose name is so well
known in the medical world. He applied him-
self particularly to the study of anatomy, and
did more in that way than all that went before
him. He seems, however, to have been at a
great loss for human subjects to operate upon;
and therefore his description of the parts are
mostly taken from brute animals. His works
contain the fullest history of anatomists, and the
most complete system of the science, to be met
with any where before him, or for several cen-
turies after; so that a number of passages in them
were reckoned absolutely unintelligible for many
ages, until explained by the discoveries of suc-
ceeding anatomists.
About the end of the fourth century, Nimesi-
us bishop of Emissa wrote a treatise on the na-
ture of man, in which it is said were contained
two celebrated modern discoveries; the one, the
uses of the bile, boasted of by Sylvius de la Boe;
and the other, the circulation of the blood. This
last, however, is proved by Dr Friend, in his
History of physic, p. 229. to be falsely ascribed
to this author.
The Roman empire beginning now to be op-
pressed 

13 INTRODUCTION. 
pressed by the barbarians, and sunk in gross su-
perstition, learning of all kinds decreased; and
when the empire was totally overwhelmed by
those barbarous nations, every appearance of
science was almost extinguished in Europe. The
only remains of it were among the Arabians in
Spain and in Asia.—The Saracens who came into
Spain, destroyed at first all the Greek books
which the Vandals had spared: but though their
government was in a constant struggle and fluc-
tuation during 800 years before they were driven
out, they received a taste for learning from their
countrymen of the east; several of their princes
encouraged liberal studies; public schools were
set up at Cordova, Toledo, and other towns,
and translations of the Greeks into the Arabic
were universally in the hands of their teachers.
Thus was the learning of the Grecians trans-
ferred to the Arabians. But though they had so
good a foundation to build upon, this art was ne-
ver improved while they were masters of the
world; for they were satisfied with commenting
upon Galen; and seem to have made no dissec-
tions of human bodies.
Abdollaliph, who was himself a teacher of
anatomy, a man eminent in his time (at and
before 1203) for his learning and curiosity; a
great traveller, who had been bred at Bagdad,
and had seen many of the great cities and prin-
cipal places for study in the Saracen empire;
who had a favourable opinion of original obser-
vation, 

14 INTRODUCTION.
vation, in opposition to book-learning; who
boldly corrected some of Galen's errors, and
was persuaded that many more might be detect-
ed; this man, we say, never made or saw, or
seemed to think of a human dissection. He dis-
covered Galen's errors in the osteology, by going
to burying-grounds, with his students and others,
where he examined and demonstrated the bones;
he earnestly recommended that method of study,
in preference even to the reading of Galen, and
thought that many further improvements might
be made; yet he seemed not to have an idea that
a fresh subject might be dissected with that view.
Perhaps the Jewish tenets, which the Maho-
metans adopted, about uncleanliness and pollu-
tion, might prevent their handling dead bodies;
or their opinion of what was supposed to pass
between an angel and the dead person, might
make them think disturbing the dead highly sa-
crilegious. Such, however, as Arabian learning
was, for many ages together there was hardly
any other in all the western countries of Europe.
It was introduced by the establishment of the
Saracens in Spain in 711, and kept its ground
till the restoration of learning in the end of the
15th century. The state of anatomy in Europe,
in the times of Arabian influence, may be seen
by reading a very short system of anatomy drawn
up by Mundinus, in the year 1315. It was ex-
tracted principally from what the Arabians had
preserved of Galen's doctrine; and, rude as it is,
in 

15 INTRODUCTION.  
in that age, it was judged to be so masterly a
performance, that it was ordered by a public
decree, that it should be read in all the schools
of Italy; and it actually continued to be almost
the only book which was read upon the subject
for above 200 years. Cortesius gives him the
credit of being the great restorer of anatomy,
and the first who dissected human bodies among
the moderns.
A general prejudice against dissection, howe-
ver, prevailed till the 16th century. The em-
peror Charles V. ordered a consultation to be
held by the divines of Salamanca, in order to
determine whether or not it was lawful in point
of conscience to dissect a dead body. In Mus-
covy, till very lately, both anatomy and the use
of skeletons were forbidden, the first as inhu-
man, and the latter as subservient to with-
craft.
In the beginning of the 15th century, learn-
ing revived considerably in Europe, and parti-
cularly physic, by means of copies of the Greek
authors brought from the sack of Constantinople;
after which the number of anatomists and ana-
tomical books increased to a prodigious degree.
—The Europeans becoming thus possessed of
the antient Greek fathers of medicine, were for
a long time so much occupied in correcting the
copies they could obtain, studying the meaning,
and commenting upon them, that they at-
tempted 

16 INTRODUCTION.
tempted nothing of their own, especially in ana-
tomy.
And here the late Dr. Hunter introduces in-
to the annals of this art, a genius of the first
rate, Leonardo da Vinci, who had been formerly
overlooked, because he was of another profession,
and because he published nothing upon the sub-
ject. He is considered by the Doctor as by far
the best anatomist and physiologist of his time;
and was certainly the first man we know of who
introduced the practice of making anatomical
drawings.
Vassare, in his lives of the painters, speaks of
Leonardo thus, after telling us that he had com-
posed a book of the anatomy of a horse, for
his own study: "He afterwards applied him-
self with more diligence to the human anatomy;
in which study he reciprocally received and
communicated assistance to Marc Antonio della
Torre, an excellent philosopher, who then read
lectures in Pavia, and wrote upon this subject;
and who was the first, as I have heard, who
began to illustrate medicine from the doctrine
of Galen, and to give true light to anatomy,
which till that time had been involved in clouds
of darkness and ignorance. In this he availed
himself exceedingly of the genius and labour of
Leonardo, who made a book of studies, drawn
with red chalk, and touched with a pen, with
great diligence, of such subjects as he had him-
self dissected; where he made all the bones, and
3 to 

17 INTRODUCTION.  
to those he joined, in their order, all the nerves,
and covered them with the muscles. And con-
cerning those, from part to part, he wrote re-
marks in letters of an ugly form, which are
written by the left hand, backwards, and not
to be understood but by those who know the
method of reading them; for they are not to
be read without a looking-glass. Of these pa-
pers of the human anatomy, there is a great
part in the possession of M. Francesco da Melzo,
a Milanese gentleman, who, in the time of Leo-
nardo, was a most beautiful boy, and much be-
loved by him, as he is now a beautiful and gen-
teel old man, who reads those writings, and care-
fully preserves them, as precious relicts, toge-
ther with the portrait of Leonardo, of happy
memory. It appears impossible that that divine
spirit should reason so well upon the arteries,
and muscles, and nerves, and veins; and with
such diligence of every thing, &c. &c."
Those very drawings and the writings are
happily found to be preserved in his Britannic
Majesty's great collection of original drawings,
where the Doctor was permitted to examine
them; and his sentiments upon the occasion he
thus expresses: "I expected to see little more
than such designs in anatomy, as might be use-
ful to a painter in his own profession; but I saw,
and indeed with astonishment, that Leonardo
had been a general and a deep student. When
I consider what pains he has taken upon every
B part

18 INTRODUCTION.
part of the body, the superiority of his univer-
sal genius, his particular excellence in mecha-
nics and hydraulics, and the attention with which
such a man would examine and see objects which
he was to draw, I am fully persuaded that Leo-
nardo was the best anatomist at that time in the
world. We must give the 15th century the cre-
dit of Leonardo's anatomical studies, as he was
55 years of age at the close of that century."
In the beginning of the 16th century, Achil-
linus and Benedictus, but particularly Beren-
garius and Massa, followed out the improvement
of anatomy in Italy, where they taught it, and
published upon the subject. These first im-
provers made some discoveries from their own
dissections: but it is not surprising that they
should have been diffident of themselves, and
have followed Galen almost blindly, when his
authority had been so long established, and when
the enthusiasm for Greek authors was rising to
such a pitch.
Soon after this, we may say about the year
1540, the great Vesalius appeared. He was
studious, laborious, and ambitious. From Brus-
sels, the place of his birth, he went to Louvain,
and thence to Paris, where anatomy was not
yet making considerable figure, and then to
Louvain to teach; from which place, very for-
tunately for his reputation, he was called to Italy,
where he met with every opportunity that such
a such genius for anatomy desire, that is, books,
subjects,

19 INTRODUCTION.  
subjects, and excellent draughtsmen. He was
equally laborious in reading the ancients, and in
dissecting bodies. And in making the compa-
rison, he could not but see, that there was great
room for improvement, and that many of Ga-
len's descriptions were erroneous. When he
was but a young man, he published a noble sys-
tem of anatomy, illustrated with a great num-
ber of elegant figures.—In this work he found
so many occasions of correcting Galen, that his
contemporaries, partial to antiquity, and jealous
of his reputation, complained that he carried his
turn for improvement and criticisms to licentious-
ness. The spirit of opposition and emulation was
presently roused; and Silvius in France, Colum-
bus, Fallopius, and Eustachius in Italy, who
were all in high anatomical reputation about the
middle of the 16th century, endeavoured to de-
fend Galen at the expence of Vesalius. In
their disputes they made their appeals to the hu-
man body: and thus in a few years the art was
greatly improved. And Vesalius being detect-
ed in the very fault which he condemned in Ga-
len, to wit, describing from the dissections of
brutes, and not of the human body, it exposed
so fully that blunder of the older anatomists, that
in succeeding times there has been little reason
for such complaint.—Besides the above, he pub-
lished several other anatomical treatises. He
has been particularly serviceable by imposing
names on the muscles, most of which are retain-
B2 ed 

20 INTRODUCTION.
ed to this day. Formerly they were distinguish-
ed by numbers, which were differently applied
by almost every author.
In 1561, Gabriel Fallopius, professor of ana-
tomy at Padua, published a treatise of anatomy
under the title of Observationes Anatomicæ. This
was designed as a supplement to Vesalius; many
of whose descriptions he corrects, though he
always makes mention of him in an honourable
manner. Fallopius made many great discoveries,
and his book is well worth the perusal of every
anatomist.
In 1563, Bartholomæus Eustachius publish-
ed his Opufcula Anatomica at Venice, which
have ever since been justly admired for the ex-
actness of the descriptions, and the discoveries
contained in them. He published afterwards
some other pieces, in which there is little of ana-
tomy; but never published the great work he
had promised, which was to be adorned with
copperplates representing all the parts of the
human body. These plates, after lying buried
in an old cabinet for upwards of 150 years, were
at last discovered and published in the year 1714,
by Lancisi the pope's physician; who added a
short explicatory text, because Eustachius's own
writing could not be found.
From this time the study of anatomy gradu-
ally diffused itself over Europe; insomuch that
for the last hundred years it has been daily im-
proving by the labour of a number of pro-
fessed 

21 INTRODUCTION.  
fessed anatomists almost in every country of Eu-
rope.
We may form a judgment about the state of
anatomy even in Italy, in the beginning of the
17th century, from the information of Cortesius.
He had been professor of anatomy at Bologna,
and was then professor of medicine at Massana;
where, though he had a great desire to improve
himself in the art, and to finish a treatise which
he had begun on practical anatomy, in 24 years
he could twice only procure an opportunity of
dissecting a human body, and then it was with
difficulties and in hurry; whereas he had ex-
pected to have done so, he says, once every year,
according to the custom in the famous academies of
Italy.
In the very end of the 16th centry, the great
Harvey, as was the custom of the times, went
to Italy to study medicine; for Italy was still the
favourite seat of the arts: And in the very be-
ginning of the 17th century, soon after Har-
vey's return to England, his master in anatomy,
Fabricius ab Aquapendente, published an ac-
count of the valves in the veins, which he had
discovered many years before, and no doubt
taught in his lectures when Harvey attended him.
This discovery evidently affected the establish-
ed doctrine of all ages, that the veins carried
the blood from the liver to all parts of the body
for nourishment. It set Harvey to work upon
the use of the heart and vascular systems in ani-
mals;

22 INTRODUCTION.
mals; and in the course of some years he was
so happy as to discover, and to prove beyond all
possibility of doubt, the circulation of the blood.
He taught his new doctrine in his lectures about
the year 1616, and printed it in 1628.
It was by far the most important step that had
been made in the knowledge of animal bodies
in any age. It not only reflected useful lights
upon what had been already found out in ana-
tomy, but also pointed out the means of further
investigation. And accordingly we see, that
from Harvey to the present time, anatomy has
been so much improved, that We may reasona-
bly question if the ancients have been further
outdone by the moderns in any other branch of
knowledge. From one day to another there has
been a constant succession of discoveries, relating
either to the structure or functions of our body;
and new anatomical processes, both of investiga-
tion and demonstration, have been daily Invent-
ed. Many parts of the body, which were not
known in Harvey's time, have since then been
brought to light: and of those which were
known, the internal composition and functions
remained unexplained; and indeed must have
remained unexplicable without the knowledge
of the circulation.
Harvey's doctrine at first met with consider-
able opposition; but in the space of about 20
years it was so generally and so warmly embrac-
ed, that it was imagined every thing in physic
would be explained. But time and experience
have

23 INTRODUCTION.
have taught us, that we still are, and probably
must long continue to be, very ignorant; and
that in the study of the human body, and of its
diseases, there will always be an extensive field
for the exercise of sagacity.
After the discovery and knowledge of the
circulation of the blood, the next question would
naturally have been about the passage and route
of nutritious part of the food or chyle from the
bowels to the blood-vessels: And, by good for-
tune, in a few years after Harvey had made his
discovery, Asellius, an Italian physician, found
out the lacteals, or vessels which carry the chyle
from the intestines; and printed his account of
them, with coloured prints, in the year 1627,
the very year before Harvey's book came out.
For a number of years after these two publi-
cations, the anatomists in all parts of Europe
were daily opening living dogs, either to see the
lacteals or to observe the phenomena of the cir-
culation. In making an experiment of this
kind, Pecquet in France was fortunate enough
to discover the thoracic duct, or common trunk
of all the lacteals, which conveys the chyle into
the subclavian vein. He printed his discovery in
the year 1651. And now the lacteals having been
traced  from the intestines to the thoracic duct,
and that duct having been traced to its termina-
tion in a blood-vessel, the passage of the chyle
was completely made out.
The same practice of opening living animals
furnish-

24 INTRODUCTION.
furnished occasions of discovering the lymphatic
vessels. This good fortune fell to the lot of
Rudbec first, a young  Swedish anatomist; and
then to Thomas Bartholine, a Danish anato-
mist, who was the first who appeared in print
upon the lymphatics. His book came out
in the year 1653, that is two years after that of
Pecquet. And then it was very evident that
they had been seen before by Dr. Higmore and
others, who had mistaken them for lacteals. But
none of the anatomists of those times could make
out the origin of the lymphatics, and none of
of the physiologists could give a satisfactory ac-
count of their use.
The circulation of the blood and the passage
of the chyle having been satisfactory traced out
in full grown animals, the anatomists were na-
turally led next to consider how these animal
processes were carried on in the child while in
the womb of the mother. Accordingly the
male and female organs, the appearances and
contents of the pregnant uterus, the incubated
egg, and every phenomenon which could illus-
trate generation, became the favourite subject,
for about 30 years, with the principal anatomists
of Europe.
Thus it would appear to have been in theory:
but Dr. Hunter believes, that in fact, as Har-
vey's master Fabricius laid the foundation for
the discovery of the circulation of the blood by
teaching him the valves of the veins, and there-
by 

25 INTRODUCTION. 
by inviting him to consider that subject; so Fa-
bricius by his lectures, and by his elegant work
De formato fœtu, et de formatione ovi et pulli,
probably made that likewise a favourite subject
with Dr. Harvey. But whether he took up
the subject of generation in consequence of his
discovery of the circulation, or was led to it by
his honoured master Fabricius, he spent a great
deal of his time in the enquiry; and published
his observations in a book De generatione anama-
lium, in the year 1651, that is six years before
his death.
In a few years after this, Swammerdam, Van
Horn, Steno, and De Graaf, excited great atten-
tion to the subject of generation, by their sup-
posed discovery that the females of vivaparous
animals have ovaria, that is, clusters of eggs in
their loins, like oviparous animals; which when
impregnated by the male, are conveyed into the
uterus: so that a child is produced from an egg
as well as a chick; with this difference, that one
is hatched within, and the other without, the
body of the mother.
Malpighi, a great Italian genius, some time
after, made considerable advances upon the sub-
ject of generation. He had the good fortune
to be the first who used magnifying glasses with
address in tracing the first appearances in the for-
mation of animals. He likewise made many
other observations and improvements in the mi-
nutiæ

26 INTRODUCTION.
nutiæ of anatomy by his microscopical labours,
and by cultivating comparative anatomy.
This distinguished anatomist gave the first
public specimen of his abilities, by printing a dis-
sertation on the lungs anno 1661; a period so
remarkable for the study of nature, that it
would be injustice to pass it without particular
notice.
At the same time flourished Laurentius Belli-
nus at Florence, and was the first who intro-
duced mathematical reasoning in physic. In
1662, Simon Pauli published a treatise De Al-
bandis ossibus. He had long been admired for the
white skeletons he prepared; and at last discove-
red his method, which was by exposing the bones
all winter to the weather.
Johannes Swammerdam of Amsterdam also
published some anatomical treatises; but was
most remarkable for his knowledge of preserv-
ing the  parts of bodies entire for many years,
by injecting their vessels. He also published a
treatise on inspiration; wherein he mentioned
his having figures of all the parts of the body
at big as the life, cut in copper, which he de-
signed to publish, with a complete system of
anatomy. These, however, were never made
public by Swammerdam; but, in 1683, Go-
thofridus Bidloo, professor of anatomy at Ley-
den, published a work intitled Anatomia corporis
humani, where all the parts were delineated in
very large plates as almost as big as the life. Mr.
Cowper,

27 INTRODUCTION.  
Cowper, an English surgeon, bought 300 co-
pies of these figures; and in 1698, published
them with an English text, quite different from
Bidloo's Latin one; to which were added letters in
Bidioo's figures, and some few figures, of Mr.
Cowper's own. To this work Cowper's name
was prefixed, without the least mention of Bid-
loo, except on purpose to confute him. Bid-
loo immediately published a very ill-natured
pamphlet, called Gulielmus Cowperus citatus coram
tribunali; appealing to the Royal Society, how
far Cowper ought to be punished as a plagiary
of the worst kind, and endeavouring to prove
him an ignorant deceitful fellow. Cowper an-
swered him in his own style, in a pamphlet call-
ed his Vindiciæ; endeavouring to prove, either
that Bidloo did not understand his own ta-
bles, or that they were none of his. It was
even alledged that those were the tables promis-
ed by Swammerdam, and which Bidloo had
got from his widow. This, however, appears
to have been only an invidious surmise, there
being unquestionable evidence that they were
really the performance of Bidloo.
Soon after, Isbrandus Diembroeck, professor
of anatomy at  Utrecht, began to appear as
an author. His work contained very little ori-
ginal; but he was at great pains to collect from
others what was valuable in their writings, and
his system was the common standard among ana-
tomical students for many years.
About the same time, Antonius Liewen-
hoeck 

28 INTRODUCTION.
hoeck of Delft, improved considerably on Mal-
pighi's use of microscopes. These two authors
took up anatomy where others had dropt it;
and, by this new art, they brought a number
of amazing things to light. They discovered
the red globules of the blood; they were ena-
bled to see the actual circulation of the blood in
the transparent parts of living animals, and could
measure the velocity of its motion; they disco-
vered that the arteries and veins had no interme-
diate cells or spungy substance, as Harvey and
all the preceding anatomists had supposed, but
communicated one with the other by a continu-
ation of the same tube.
Liewenhoeck was in great same likewise for
his discovery of the animalcula in the semen.
Indeed there was scarcely a part of the body,
solid or fluid, which escaped his examination;
and he almost every where found, that what
appeared to the naked eye to be rude undigest-
ed matter, was in reality a beautiful and regular
compound.
After this period, Nuck added to our know-
ledge of the absorbent system already mentioned,
by his injections of the lymphatic glands; Ruysch,
by his description of the valves of the lymphatic
vessels; and Dr. Meckel, by his accurate ac-
count of the whole system, and by tracing those
vessels in many parts where they had not before
been described.
Besides these authors, Drs. Hunter and Monro
have 

29 INTRODUCTION.
have called the attention of the public to this
part of anatomy, in their controversy concern-
ing the discovery of the office of the lympha-
tics.
When the lymphatic vessels were first seen and
traced into the thoracic duct, it was natural for
anatomists to suspect, that as the lacteals absorb-
ed from the cavity of the intestines, the lym-
phatics, which are similar in figure and struc-
ture, might possibly do the same office with
respect to other parts of the body: and accord-
ingly, Dr. Glisson, who wrote in 1654, sup-
poses 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.
But anatomists in general have been of a con-
trary opinion; for, from experiments, particu-
larly such as were made by injections, they have
been persuaded that the lymphatic vessels did not
arise from cavities, and did not absorb, but were
merely continuations from small arteries. The
doctrine, therefore, that the lymphatics, like
the lacteals, were absorbents, as had been sug-
gested by Glisson and by Hoffman, has been
revived by Dr. Hunter and Dr. Monro, who
have controverted the experiments of their pre-
decessors in anatomy, and have endeavoured to
prove that the lymphatic vessels are not continu-
ed from arteries, but are absorbents.
To this doctrine, however, several objections
have 

30 INTRODUCTION.
have been started, particularly by Haller (Elm.
Phys. 1. 24. § 2, 3.); and it has been found, that
before the doctrine of the lymphatics being a system
of absorbents can be established, it must first be
determined whether this system is to be found in
other animals besides man and quadrupeds. Mr.
Hewson claims the merit of having proved the
affirmative of this question, by discovering the
lymphatic system in birds, fish, and amphibious
animals. See Phil. Trans. vol. lviii. and lxix.
—And latterly, Mr. Cruikshank has traced the
ramifications of that system in almost every part
of the body; and from his dissections, figures
have been made and lately published to the
world. To Mr. Seldon also we are much in-
debted for his illustration of this system, which
promises to give great satisfaction, but of which
only a part has yet been published.
The gravid uterus is a subject likewise which
has received considerable improvements, parti-
cularly relating to one very important discovery;
viz. that the internal membrane of the uterus,
which Dr. Hunter has named decidua, consti-
tutes the exterior part of the secundines or after-
birth, and separates from the rest of the uterus
every time that a woman either bears a child or
suffers a miscarriage. This discovery includes
another, to wit, that the placenta is partly made
up of an excreccence or efflorescence from the
uterus itself.
These discoveries are of the utmost conse-
3 quence,


31 INTRODUCTION.
quence, both in the physiological question about
the connection between the mother and child,
and likewise in expiring the phenomena of
births and abortions, as well as in regulating ob-
stetrieal practice.
The anatomists of this century have improv-
ed anatomy, and have made the study of it much
more easy by giving us more correct as well as
more numerous figures. It is amazing to think
of what has been done in that time. We have
had four large folio books of figures of the
bones, viz. Cheselden's, Albinus's, Sue's and
Trew's. Of the muscles, we have had two large
folio's; one from Cowper, which is elegant;
and one from Albinus, which from the accuracy
and labour of the work, we may suppose will
never be outdone. Of the blood vessels we
have a large folio from Dr. Haller. We have
had one upon the nerves from Dr. Meckel, and
another by Dr. Monro, junior. We have had
Albinus's, Roederer's, Jenty's, and Hunter's
works upon the pregnant uterus; Weitbrecht
and Leber on the joints and fresh bones; Soe-
merring on the brain; Zin on the eye; Cotun-
nius, Mekel, junior, &c. on the ear; Walterus
on the nerves of the thorax and abdomen; Dr.
Monro on the bursæ mucosæ, &c.
It would be endless to mention the anatomical
figures that have been published in this century,
of particular and smaller parts of the body, by
Morgagni, Ruysch, Valsalva, Sanctorini, Hei-
ster, 

32 INTRODUCTION.
ster, Vater, Cant, Zimmerman, Walterus, and
others.
Those elegant plates of the brain, however,
just published by M. Vicq. d'Azyr, must not
pass without notice, especially as they form part
of an universal system of anatomy and physi-
ology, both human and comparative, proposed
to be executed in the same splendid style. Up-
on the brain alone 19 folio plates are employed;
of which several are coloured. The figures are
delineated with accuracy and clearness; but the
colouring is rather beautiful than correct. Such
parts of this work as may be published, cannot
fail to be equally acceptable to the anatomist and
the philosopher; but the entire design is appa-
rently too extensive to be accomplished within
the period of a single life. In Great Britain,
also, a very great anatomical work is carrying
on by Andrew Bell, F.S.A.S. engraver to his
Royal Highness the Prince of Wales, with the
approbation of Dr. Monro, and under the in-
spection of his very ingenious assistant Mr. Fyfe.
It is to compose a complete illustration, both ge-
neral and particular, of the human  body, by a
selection from the best plates of all the greatest
anatomists, as well foreign as British, exhibit-
ing the latest discoveries in the science, and ac-
companied with copious explanations. The
whole number of plates mentioned in the Pro-
spectus is 240, of which 152 are already done;
all in royal folio.
To

33 INTRODUCTION. 
To the foreign treatises already mentioned may
be added those recently published by Sabbatier
and Plenck on anatomy in general. In Great-
Britain, the writings of Keil, Douglas, Chesel-
den, the first Monro, Winslow, &c. are too well
known to need description. The last of these
used to be recommended as a standard for the Stu-
dents of anatomy: but it has of late given place
to a more accurate and comprehensive system,
in three volumes, published by Mr Elliot of
Edinburgh, upon a plan approved of by Dr Mon-
ro, and executed by Mr Fyfe. Dr Simmons
of London has also obliged the world with an
excellent system of anatomy; and another work,
under the title of "Elements of Anatomy and
the Animal Œconomy: in which the subjects
are treated with uncommon elegance and perspi-
cuity.
In the latter part of the last century, anatomy
made two great steps, by the invention of injec-
tions, and the method of making what we com-
monly call preparations. These two modern arts
have really been of infinite use to anatomy; and
besides have introduced an elegance into our ad-
ministrations, which in former times could not
have been supposed to be possible. They arose
in Holland under Swammerdam and Ruysch,
and afterwards in England under Cowper, St.
André, and others, where they have been greatly
improved.
C The 


34 INTRODUCTION.
The anatomists of former ages had no other
knowledge of the blood-vessels, than what they
were able to collect from laborious dissections,
and from examining the smaller branches of them,
upon some lucky occasion, when they were found
more than commonly loaded with red blood.
But filling the vascular system with a bright co-
loured wax, enables us to trace the large vessels
with great ease, renders the smaller much more
conspicuous, and makes thousands of the very
minute ones visible, which from their delicacy,
and the transparency of their natural contents,
are otherwise imperceptible.
The modern art of corroding the fleshy parts
with a menstruum, and of leaving the moulded
wax entire, is so exceedingly useful, and at the
fame time so ornamental, that it does great honour
to the ingenious inventor Dr Nicholls.
The wax-work art of the moderns might de-
serve notice in any history of anatomy, if the
masters in that way had not been so careless in
their imitation. Many of the wax-figures are
so tawdry with a show of unnatural colours, and
so very incorrect in the circumstances of figure,
Situation, and the like, that though they strike
a vulgar eye with admiration, they must appear
ridiculous to an anatomist. But those figures
which are cast in wax, plaster, or lead, from the
real subject, and which of late years have been
frequently made, are, of course, very correct in
all the principal parts, and may be considered as
no 

35 INTRODUCTION.
no insignificant acquisition to modern anatomy.
The proper, or principal use of this art is, to pre-
serve a very perfect likeness of such subjects as
we but seldom can meet with, or cannot well
preserve in a natural state; a subject in pregnan-
cy, for example.
The modern improved methods of preserving
animal bodies, or parts of them, has been of
the greatest Service to anatomy; especially in
saving the time and labour of the anatomist in
the nicer dissections of the small parts of the bo-
dy. For now, whatever he has prepared with
care, he can preserve; and the object is ready to
be seen at any time. And in the same manner
he can preserve anatomical curiosities, or rarities
of every kind; such as, parts that are uncom-
monly formed; parts that are diseased; the parts
of the pregnant uterus and its contents. Large
collections of such curiosities which modern
anatomists are striving almost every where to
procure, are of infinite service to the art, espe-
cially in the hands of teachers. They give stu-
dents clear ideas about many things which it is
very essential to know, and yet which it is im-
possible that a teacher should be able to show
otherwise, were he ever so well supplied with
fresh subjects.
C2 § 2. View 


36 INTRODUCTION.
§ 2. View of the Subject in general, and Plan of
the following Treatise.
The etymology of the word anatomy, as above
given, implies simply dissection; but by this term
something more is usually understood.
It is every day made use of to express a know-
ledge of the human body; and a person who
is said to understand anatomy, is supposed to be
conversant with the structure and arrangement of
the different solid parts of the body.
It is commonly divided into Anatomy, pro-
perly so called; and Comparative Anatomy: the
first of these is confined solely to the human bo-
dy; the latter includes all animals, so far as a
knowledge of their structure may tend to perfect
our ideas of the human body. See COMPARA-
TIVE Anatomy.
The term anatomy may also have another and
more extensive signification: it may be employ-
ed to express not only a knowledge of the struc-
ture and disposition of the parts but likewise of
their economy and use. Considered in this light,
it will seldom fail to excite the curiosity of peo-
ple of taste, as a branch of philosophy; since, if
it is pleasing to be acquainted with the structure
of the body, it is certainly more so to discover all
the springs which give life and motion to the
machine, and to observe the admirable mechan-
ism by which so many different functions are ex-
ecuted.
Astronomy and anatomy, as Dr Hunter, after
Fontenelle, 

37 INTRODUCTION.
Fontenelle, observes, are the studies which pre-
sent us with the most striking view of the two
greatest attributes of the Supreme Being. The
first of these fills the mind with the idea of his
immensity, in the largeness, distances, and num-
ber of the heavenly bodies; the last, astonishes
with his intelligence and art in the variety and
delicacy of animal mechanism.
The human body has been commonly enough
known by the name of microcosmus, or the little
world; as if it did not differ so much from the
universal system of nature in the symmetry and
number of its parts as in their size.
Galen's excellent treatise De usu partium, was
composed as a prose hymn to the Creator; and
abounds with as irresistible proofs of a Supreme
Cause and governing Providence, as we find in
modern physicotheology. And Cicero dwells more
on the structure and œconomy of animals than
on all the productions of nature besides, when he
wants to prove the existence of the gods from
the order and beauty of the universe. He there
takes a survey of the body of man in a most ele-
gant synopsis of anatomy, and concludes thus:
"Quibus rebus expositis, satis docuisse videor,
hominis natura, quanto omnes anteiret animan-
tes. Ex quo debet intelligi, nec figuram situmque
membrorum, nec ingenii mentisque vim talem
effici potuisse fortuna."
The satisfaction of mind which arises from the
study of anatomy, and the influence which it
must 

38 INTRODUCTION.
must naturally have upon our minds as philoso-
phers, cannot be better conveyed than by the
following passage from the fame author: "Quæ
contuens animus, accepit ab his cognitionem de-
orem, ex qua oritur pietas: cui conjuncta justi-
tia est, reliquæque virtutes: ex quibus vita beata
exsistit, par et similes deorum, nulla alia re nisi
immortalitate, quæ nihil ad bene vivendum per-
tinet, cedens cœlestibus."
It would be endless to quote the animated
passages of this sort which are to be found in the
physicians, philosophers, and theologists, who
have considered the structure and functions of
animals with a view towards the Creator. It is
a view which must strike one with a most awful
conviction.  Who can know and consider the
thousand evident proofs of the astonishing art of
the Creator, in forming and sustaining an animal
body such as ours, without feeling the most plea-
sant enthusiasm? Can we seriously reflect upon
this awful subject, without being almost lost in
adoration? without longing for another life
after this, in which we may be gratified with the
highest enjoyment, which our faculties and na-
ture seem capable of, the seeing and comprehend-
ing the whole plan of the Creator, in forming
the universe and in directing all its operations?
But the more immediate purposes of anatomy
concern those who are to be the guardians of
health, as this study is necessary to lay a foun-
dation for all the branches of medicine. The
more 

39 INTRODUCTION.
more we know of our fabric, the more reason
we have to believe, that if our senses were more
acute, and our judgment more enlarged, we
should be able to trace many springs of life which
are now hidden from us: by the same sagacity
we should discover the true causes and nature of
diseases; and thereby be enabled to restore the
health of many, who are now, from our more
confined knowledge, said to labor under incura-
ble disorders. By such an intimate acquaintance
with the œconomy of our bodies, we should dis-
cover even the seeds of diseases, and destroy
them before they had taken root in the constitu-
tion.
That anatomy is the very basis of surgery eve-
ry body allows. It is dissection alone that can
teach us, where we may cut the living body
with freedom and dispatch; and where we may
venture with great circumspection and delicacy;
and where we must not, upon any account, at-
tempt it. This informs the head, gives dexterity
to the hand, and familiarizes the heart with a
sort of necessary inhumanity, the use of cutting-
instruments upon our fellow-creatures.
Besides the knowledge of our body, through
all the variety of its structure and operations in a
sound state, it is by anatomy only that we can ar-
rive at the knowledge of the true nature of most
of the diseases which afflict humanity. The
symptoms of many disorders are often equivo-
cal; and diseases themselves are thence frequent- 
ly

40 INTRODUCTION.
ly mistaken, even by sensible, experienced, and
attentive physicians. But by anatomical exa-
mination after death, we can with certainty find
out the mistake, and learn to avoid it in any simi-
lar case.
This use of anatomy has been so generally
adopted by the moderns, that the cases already
published are almost innumerable:  Mangetus,
Morgagni, indeed  many of the best modern
writings in physic, are full of them. And if
we look among the physicians of the best charac-
ter, and observe those who have the art itself,
rather than the craft of the profession at heart;
we Shall find them constantly taking pains to pro-
cure leave to examine the bodies of their pati-
ents after death.   
After having considered the rise and progress
of anatomy; the various discoveries that have
been made in it, from time to time; the great
number of diligent observers who have applied
themselves to this art; and the importance of
the study, not only for the prevention and cure
of diseases, but in furnishing the liveliest proofs
of divine wisdom; the following questions seem
naturally to arise: For what purpose is there
such a variety of parts in the human body? Why
such a complication of nice and tender machine-
ry? Why was there not rather a more simple,
less delicate, and less expensive frame (A)?
In
(A) The following beautiful representation is taken from
the late Dr Hunter's Introductory Lecture in Anatomy.

41 INTRODUCTION.
In order to acquire a satisfactory general idea
of this subject, and find a solution of all such
questions, let us, in our imaginations, make a
man : in other words let us suppose that the
mind, or immaterial part, is to be placed in a cor-
poreal fabric, in order to hold a correspondence
with other material beings by the intervention of
the body; and then consider, a priori, what will
be wanted for her accommodation. In this in-
quiry, we shall plainly see the necessity or advan-
tage, and therefore the final cause, of most of
the parts which we actually find in the human
body. And if we consider that, in order to an-
swer some of the requisites, human wit and in-
vention would be very insufficient; we need not
be surprised if we meet with some parts of the
body whose use we cannot yet perceive, and with
some operations and functions which we cannot
explain. We can see that the whole bears the
most striking characters of excelling wisdom and
ingenuity: but the imperfect senses and capacity
of man cannot pretend to reach every part of a
machine, which nothing less than the intelligence
and power of the Supreme Being could contrive
and execute.
First, then, the mind, the thinking, immate-
rial agent, must be provided with a place of im-
mediate residence, which shall have all the re-
quisites for the union of spirit and body; ac-
accordingly she is provided with the brain, where
she 

42 INTRODUCTION.
she dwells as governor and superintendant of the
whole fabric.                           
In the next place, as she is to hold a corres-
pondence with all the material beings around her,
she must be supplied with organs fitted to receive
the different kinds of impressions which they will
make. In fact, therefore, we see that she is pro-
vided with the organs of sense, as we call them:
the eye is adapted to light; the ear to sound; the
nose to smell; the mouth to taste; and the skin
to touch.
Further: She must be furnished with organs
of communication between herself in the brain
and those organs of sense, to give her informa-
tion of all the impressions that are made upon
them: and she must have organs between herself
in the brain and every other part of the body,
fitted to convey her commands and influence over
the whole. For these purposes the nerves are
actually given. They are chords, which rise
from the brain, the immediate residence of the
mind, and  disperse themselves in branches
through all parts of the body. They convey all
the different kinds of sensations to the mind, in
the brain; and likewise carry out from thence
all her commands or influence to the other parts
of the body. They are intended to be occasion-
al monitors against all such impressions as might
endanger the well-being of the whole, or of any
particular part; which vindicates the Creator of
all things, in having actually subjected us to
those 

43 INTRODUCTION.
those many disagreeable and painful sensations
which we are exposed to from a thousand acci-
dents in life.
Moreover, the mind, in this corporeal system,
must be endued with the power of moving from
place to place, that she may have intercourse
with a variety of objects; that she may fly from
such as are disagreeable, dangerous or hurtful,
and pursue such as are pleasant or useful to her.
And accordingly she is furnished with limbs, and
with muscles and tendons, the instruments of mo-
tion, which are found in every part of the fabric
where motion is necessary.
But to support, to give firmness and shape to
the fabric; to keep the softer parts in their pro-
per places; to give fixed points for, and the pro-
per direction to its motions, as well as to protect
some of the more important and tender organs
from external injuries; there must be some firm
prop-work interwoven through the whole. And,
in fact, for such purposes the bones are given.
The prop-work must not be made into one
rigid fabric, for that would prevent motion.
Therefore there are a number of bones.
These pieces must all be firmly bound toge-
ther, to prevent their dislocation. And this end
is perfectly well answered by the ligaments.
The extremities of these bony pieces, where
they move and rub upon one another, must have
smooth and slippery surfaces for easy motion.
This 

44 INTRODUCTION.
This is most happily provided for, by the carti-
lages and mucus of the joints.
The interstices of all those parts must be filled
up with Some Soft and ductile matter, which shall
keep them in their places, unite them, and at
the same time allow them to move a little upon
one another. And these purposes are answered
by the cellular membrane or adipose substance.
There must be an outward covering over the
whole apparatus, both to give it compactness and
to defend it from a thousand injuries: which, in
fact, are the very purposes of the skin and other
integuments.
Lastly, the mind being formed for society and
intercourse with  beings of her own kind, she
must be endued with powers of expressing and
communicating her thoughts by some sensible
marks or signs; which shall be both easy to her-
self, and admit of great variety; and according-
ly she is provided with the organs and faculty of
speech, by which she can throw out signs with
amazing facility, and vary them without end.
Thus we have built up an animal body which
would seem to be pretty complete: but as it is
the nature of matter to be altered and worked
upon by matter; so in a very little time such a
living creature must be destroyed, if there is no
provision for repairing the injuries which she
must commit upon herself, and those which she
must be exposed to from without. Therefore a
treasure of blood is actually provided in the heart
and 

45 INTRODUCTION.
and vascular system, full of nutritious and heal-
ing particles, fluid enough to penetrate into the
minutest parts of the animal; impelled by the
heart, and conveyed by the arteries, it washes
every part, builds up what was broken down,
and sweeps away the old and useless materials.
Hence we see the necessity or advantage of the
heart and arterial system.
What more there was of this blood than
enough to repair the present damages of  the ma-
chine, must not be lost, but should be returned
again to the heart; and for this purpose the ve-
nous system is actually provided. These requi-
sites in the animal explain, a priori, the circula-
tion of the blood.
The old materials which were become useless,
and are swept off by the current of blood, must
be separated and thrown out of the system.
Therefore glands, the organs of secretion, are
given for straining whatever is rudundant, vapid,
or noxious, from the mass of blood; and when
strained, they are thrown out by emunctories,
called organs of Excretion.
But now, as the machine must be constantly
wearing the reparation must be carried on with-
out intermission, and the strainers must always
be employed. Therefore there is actually a per-
petual circulation of the blood, and the secretions
are always going on.
Even all this provision, however, would not
be sufficient; for that store of blood would soon
be

46 INTRODUCTION.
be consumed, and the fabric would break down,
if there were not a provision made for fresh Sup-
plies. These we observe, in fact, are profusely
Scattered round her in the animal and vegetable
kingdoms; and she is furnished with hands, the
fittest instruments that could have been contrived,
for gathering them, and for preparing them in a
variety of ways for the mouth.
But these supplies, which we call food, must
be considerably changed; they must be convert-
ed into blood. Therefore she is provided with
teeth for cutting and bruising the food, and with
a stomach for melting it down: In short, with
all the organs subservient to digestion. The finer
parts of the aliments only can be useful in the
constitution: these must be taken up and con-
veyed into the blood, and the dregs must be
thrown off. With this view the intestinal canal
is actually given. It separates the nutritious
part, which we call chyle, to be conveyed into
the blood by the system of absorbent vessels; and
the feces pass downwards, to be conducted out
of the body.
Now we have got our animal not only furnish-
ed with what is wanted for its immediate exist-
ence, but also with the powers of protracting that
existence to an indefinite length of time. But its
duration, we may presume, must necessarily be
limited: for as it is nourished, grows, and is
raised up to its full Strength and utmost perfection;
so it must, in time, in common with all material
beings, 

47 INTRODUCTION. 
beings, begin to decay, and then hurry on to fi-
nal ruin. Hence we see the necessity of a scheme
for renovation. Accordingly wise Providence,
to perpetuate as well as preserve his work, be-
sides giving a Strong appetite for life and self-pre-
servation, has made animals male and female,
and given them such organs and passions as will
secure the propagation of the species to the end
of time.
Thus we see, that by the very imperfect sur-
vey which human reason is able to take of this
subject, the animal man must necessarily be
complex in his corporeal system, and in its ope-
rations.
He must have one great and general system,
the vascular, branching through the whole for cir-
culation: Another, the nervous, with its append-
ages the organs of sense, for every kind of feel-
ing: And a third, for the union and connection
of all those parts.
Besides these primary and general systems, he
requires others which may be more local or con-
fined: One for Strength, Support, and protection;
the bony compages: Another for the requisite
motions of the parts among themselves, as well
as for moving from place to place; the muscu-
lar part of the body: Another to prepare nourish-
ment for the daily recruit of the body; the di-
gestive organs: And one for propagating the spe-
cies; the organs of generation.
And in taking this general Survey of what
would 

48 INTRODUCTION.
would appear, a priori, to be necessary for adapt-
ing an animal to the situations of life, we observe,
with great satisfaction, that man is accordingly
made of such systems, and for such purposes.
He has them all; and he has nothing more, ex-
cept the organs of respiration. Breathing it
seemeth difficult to account for a priori: we only
knew it to be in fact essentially necessary to life.
Notwithstanding this, when we saw all the other
parts of the body, and their functions, so well
accounted for, and so wisely adapted to their se-
veral purposes, there could be no doubt that res-
piration was so likewise: And accordingly, the
discoveries of Dr Priestley have lately thrown
light upon this function also, as will be shown in
its proper place.
Of all the different systems in the human bo-
dy, the use and necessity are not more apparent,
than the wisdom and contrivance which has been
exerted in putting them all into the most com
pact and convenient form: in disposing them so,
that they shall mutually receive, and give helps
to one another; and that all, or many of the
parts, shall not only answer their principal end
or purpose, but operate successfully and usefully
in a variety of secondary ways.
If we consider the whole animal machine in
this light, and compare it with any machine in
which human art has exerted its utmost; sup-
pose the best constructed ship that ever was built,
we shall be convinced beyond the possibility of
3 doubt,


49 INTRODUCTION.
doubt, that there are intelligence and power far
surpassing what humanity can boast of.
One superiority in the natural machine is pe-
culiarly striking. In machines of human con-
trivance or art, there is no internal power, no
principle in the machine itself, by which it can
alter and accommodate itself to any injury which
it may suffer, or make up any injury which ad-
mits of repair. But in the natural machine, the
animal body, this is most wonderfully provided
for, by internal powers in the machine itself;
many of which are not more certain and obvious
in their effects, than they are above all human
comprehension as to the manner and means of
their operation. Thus, a wound heals up of it-
self; a broken bone is made firm again by a cal-
lus; a dead part is separated and thrown off;
noxious juices are driven out by some of the
emunctories; a redundancy is removed by some
spontaneous bleeding; a bleeding naturally stops
of itself; and a great loss of blood, from any
cause, is in some measure compensated, by a con-
tracting power in the vascular system, which ac-
commodates the capacity of the vessels to the
quantity contained. The stomach gives informa-
tion when the supplies have been expended; re-
presents, with great exactness, the quantity and
the quality of what is wanted in the present state
of the machine; and in proportion as she meets
with negect, rises in her demand, urges her pe-
tition in a louder tone, and with more forcible
D arguments.


50 INTRODUCTION.
arguments. For its protection, an animal bo-
dy resists heat and cold in, a very wonderful
manner, and preserves an equal temperature in a
burning and in a freezing atmosphere.
A farther excellence or superiority in the na-
tural machine, if possible, still more astonishing,
more beyond all human comprehension, than
what we have been, speaking of, is the follow-
ing. Besides those internal powers of self-pre-
servation in each individual, when two of them
co-operate, or act in concert, they are endued
with powers of making other animals or ma-
chines like themselves, which again are possessed
of the same powers of producing others, and so
of multiplying the species without end.
These are powers which mock all human in-
vention or imitation. They are characteristics
of the divine Architect.
Having premised this general account of the
subject, we shall next consider the method to be
observed in treating it.
The study of the human body, as already no-
ticed, is commonly divided into two parts. The
first, which is, called Anatomy, relates to the mat-
ter and structure of its parts; the second, called
Physiology and Animal œconomy, relates to the
principles and laws of its internal operations and
functions.
As the body is a compound of solids and fluids,
Anatomy, is divided into,
1. The Anatomy of the solids, and 

51 INTRODUCTION.
2. The Anatomy of the fluids.
I. The SOLIDS, by which we mean all parts
of our body, which are not fluid, are generally
divided into two classes, viz.
1. The hard solids or bones. This part of
anatomy is called Osteology; which signifies the
doctrine of the bones.
2. The softer solids; which part is called
Sarcology, viz. the doctrine of flesh.
This division of the solids, we may observe,
has probably taken its origin from the vulgar ob-
servation, that the body is made of bone and
flesh. And as there are many different kinds of
what are called soft or fleshy parts, Sarcology is
subdivided into,
(1.) Angeiology, or the doctrine of vessels; by
which is commonly understood blood vessels:
(2.) Adenology, of glands:
(3.) Neurology, of nerves:
(4.) Myology, of muscles: and,
(5.) Splanchnology, of the viscera or bowels.
There is, besides, that part which treats of the
organs of sense and of the integuments.
This division of the solids has been here men-
tioned, rather for the sake of explaining so ma-
ny words, which are constantly used by anato-
mists, than for its importance or accuracy. For
besides many other objections that might be urg-
ed, there are in the body three species of solids,
viz. gristle or cartilage, hair, and nails; which
are of an intermediate nature between bone and
D2 flesh; 


52 INTRODUCTION.
flesh; and therefore cannot so properly be
brought into the osteology or the sarcology. The
cartilages were classed with the bones; because
the greatest number of them are appendages to
bones: and for the like reason the hair and the
nails were classed with the integuments.
II. THE FLUIDS of the human body may be
divided into three kinds, which Dr. Hunter calls
the crude, the general or perfect, and the local
or secreted fluid.
1. By the crude fluid is meant the chyle, and
whatever is absorbed at the surface of the body,
in other words, what is recently taken into the
body, and is not yet mixed with or converted
into blood.
2. The general or perfect fluid is the blood
itself, to wit, what is contained in the heart,
arteries, and veins, and is going on in the round
of the circulation.
3. The local or secreted, are those fluids pe-
culiar to particular parts of the body, which
are strained off from the blood, and yet are very
different in their properties from the blood. They
are commonly called secretions; and some are
useful, others excrementitious.
In treating of the Physiology, it is very diffi-
cult to say what plan should be followed; for
every method which has been yet proposed, is
attended with manifest inconvenience. The
powers and operations of the machine have such
a dependence upon one another, such connec-
tions 

53 INTRODUCTION.
tions and reciprocal influence, that they cannot
well be understood or explained separately. In
this sense our body may be compared to a
circular chain of powers, in which nothing
is first or last, nothing solitary or indepen-
dent; so that wherever we begin, we find
that there is something preceding which we
ought to have known. If we begin with the
brain and the nerves, for example, we shall
find that these cannot exist, even in idea, with-
out the heart: if we set out with the heart and
vascular-system, we shall presently be sensible,
that the brain and nerves must be supposed: or,
should we take up the mouth, and follow the
course of the aliment, we should see that the very
first organ which presents itself, supposes the
existence of both the heart and the brain: where-
fore we shall incorporate the Physiology with
the Anatomy, by attempting to explain the
functions after we have demonstrated the or-
gans.
PART I.

54 
Part I. OSTEOLOGY. 
PART I.
OSTEOLOGY.
WE begin with the bones, which may be
considered as the great support of the body, tend-
ing to give it shape and firmness.—But before
we enter into the detail of each particular bone,
it will be necessary to describe their composition
and connections, and to explain the nature of
the different parts which have an immediate re-
lation to them; as the cartilages, ligaments,
periosteum, marrow, and synovial glands.
Sect. I. Of the Bones in general, with their
appendages, &c.
THE BONES are of a firm and hard (B) sub-
stance, of a white colour, and perfectly insen-
sible. They are the most compact parts of the
body, and serve for the attachment and support
of all the other parts.
Three different substances are usually distin-
guished in them; their exterior or bony part,
properly so called; their spongy cells; and their
reticular
(B) Mr. Scheele has lately discovered that bones contain
the phosphoric acid united with calcareous earth; and that
to this combination they owe their firmness.

55
Part I. OSTEOLOGY.
reticular substance. The first of these is form-
ed of many laminae or plates, composing a firm
hard substance—The spongy or cellular part is
so called on account of its resemblance to a sponge,
from the little cells which compose it. This
substance forms almost the whole of the extre-
mities of cylindrical bones. The reticular part
is composed of fibres, which cross each other
in different directions. This net-work forms
the internal surface of those bones which have
cavities.
The flat bones, as those of the head, are com-
posed only of the laminæ and the cellular sub-
stance. This last is usually found in the middle
of the bone dividing it into two plates, and is
there called diplöe.
Gagliardi, who pretended to have discovered
an infinite number of claviculi (c), or bony
processes, which he describes as traversing the la-
minæ to unite them together, has endeavoured
to support this pretended discovery by the ana-
logy of bones to the bark of trees, in which cer-
tain woody nails have been remarked;  but this
opinion seems to be altogether fanciful.
Some writers have supposed, that the bones
are formed by layers of the periosteum, which
gradually ossify, in the same manner as the tim-
ber is formed in trees by the hardening of the
white
(c) In his Anat. ossium nov. invent. illustrat. he describes
four kinds of these claviculi or nails, viz. the perpendicular,
oblique, headed, and crooked.

56 
Part I. OSTEOLOGY. 
white substance that is found between the inner
bark and the wood. M. Duhamel, who has
adopted this opinion, fed different animals with
madder and their ordinary food alternately du-
ring a certain time; and he asserts, that in dis-
secting their bones, he constantly observed dis-
tinct layers of red and white, which corresponded
with the length of time they they had lived on
madder or their usual aliment. But it has since
been proved by Detleff, that M. Duhamel's ex-
periments were inaccurate, and that neither the
periosteum nor the cartilages are tinged by the use
of madder, which is known to affect the bones
only.
We usually consider in a bone, its body and
its extremities. The ancients gave the name of
diaphysis to the body or middle part, and divi-
ded the extremities into apophysis and epiphysis.
An apophysis, or process, as it is more common-
ly called, is an eminence continued from the bo-
dy of the bone, whereas an epiphysis is at first a
sort of appendage to the bone, by means of an
intermediate cartilage. Many epiphyses, which
appear as distinct bones in the fœtus, afterwards
become apophyses; for they are at length so com-
pletely united to the body of the bone as not to
be distinguishable from it in the adult state. It
is not unusual, however, at the age of 18 and
even 20 years, to find the extremities of bones
still in the state of epiphysis.
The names given to the processes of bones
are

57
Part I. OSTEOLOGY.
are expressive of their shape, size, or use; thus
if a process is large and of a spherical form, it is
called caput, or head; if the head is flatted, it
is termed condyle. Some processes, from their
resemblance to a stiletto, a breast, or the beak of
a crow, are called styloid, mastoid, or coracoid:
others are styled ridges or spines. The two pro-
cesses of the os femoris derive their name of
trochanters from their use.
A bone has its cavities as well as processes.
These cavities either extend quite through its
substance, or appear only as depressions. The
former are called foramina or holes, and these
foramina are sometimes termed canals or conduits,
according to their form and extent. Of the de-
pressions, some are useful in articulation. These
are called cotyloid when they are deep, as is the
case with the os innominatum, where it receives
the head of the os femoris; or glenoid when they
are superficial, as in the scapula, where it re-
ceives os humeri. Of the depressions that are
not designed for articulation, those which have
small apertures are called sinuses; others that are
large, and not equally surrounded by high brims,
are styled fossæ; such as are long and narrow,
furrows; or if broad and superficial without
brims, sinuosities. Some are called digital im-
pressions, from their resemblance to the traces of
a finger on soft bodies.
We shall abridge this article, which is exceed-
ingly diffuse in the generality of anatomical
books,

58 
Part I. OSTEOLOGY. 
books, and will endeavour to describe it with all
the clearness it will allow.
The BONES composing the skeleton are so con-
structed, that the end of every bone is perfect-
ly adapted to the extremity of that with which it
is connected, and this connection forms what is
called their articulation.
Articulation is divided into diarthrosis, synar-
throsis, and amphiarthrosis, or moveable,  im-
moveable, and mixed articulation. Each of the
two first has its subdivisions. Thus the Diar-
throsis, or moveable articulation, includes, 1. The
enarthrosis, as it is called, when a large head is
admitted into a deep cavity, as in the articula-
tion of the os femoris with the os innominatum.
2. Arthrodia, when a round head is articulated
with a supeficial cavity, as is the case of the os
humeri and scapula. 3. Ginglimus, or hinge-
like articulation, as in the connection of the
thigh-bone with the tibia. The enarthrosis and
arthrodia allow of motion to all sides; the gin-
glimus only of flexion and extension.
The synarthrosis, or immoveable articulation,
includes, 1. The future, when the two bones
are indented into each other, as is the case with
the parietal bones. 2. Gomphosis, when one
bone is fixed into another, in the  manner the
teeth are placed in their sockets.
The term amphiarthrosis is applied to those
articulations which partake both of the synar-
throsis and diarthrosis, as is the case with the
bones

59
Part I. OSTEOLOGY.
bones of the vertebræ, which are capable of mo-
tion in a certain degree, although they are firm-
ly connected together by intermediate carti-
lages.
What is called symphysis is the union of two
bones into one;  as in the lower jaw, for in-
stance, which in the fœtus consists of two dis-
tinct bones, but becomes one in a more advanc-
ed age, by the ossification of the uniting carti-
lage.
When bones are thus joined by the means or
cartilages, the union is styled synchondrosis; when
by ligaments, syneurosis.
CARTILAGES are white, solid, smooth, and
elastic substances, between the hardness of bones
and ligaments, and seemingly of a fibrous tex-
ture. We are not able to trace any vessels into
their Substance by injection, nor are they ever
found tinged in animals that have been fed
with madder.
They may be distinguished into, 1st. Those
which are connected with the bones; and 2dly.
Those which belong to other parts of the body.
The first serve either to cover the ends and ca-
vities of bones intended for motion, as in the
articulations, where by their smoothness they fa-
cilitate motions, which the bones alone could not
execute with so much freedom; or they serve
to unite bones together, as in the symphysis pu-
bis, or to lengthem them, as in the ribs.
Many of them ossifying as we advance in life,
these

60 
Part I. OSTEOLOGY. 
their number is less in the adult than in the fœtus,
and of course there are fewer bones in the old
than in the young subject.
Of the second class of cartilages or those be-
longing to the soft parts, we have instances in
the larynx, where we find them useful in the
formation of the voice, and for the attachment
of muscles.
The PERIOSTEUM is a fine membrane of a
compact cellular texture, reflected from one joint
to another, and serving as a common covering to
the bones. It has sanguiferous and lymphatic
vessels, and is supplied with nerves from the
neighbouring parts. It adheres very firmly to
their surface, and by its smoothness facilitates the
motion of muscles. It likewise supports the ves-
sels that go to be distributed through the substance
of the bones, and may serve to strengthen the
articulations. At the extremities of bones, where
it is found covering a cartilage, it has by some
been improperly considered as a distinct mem-
brane, and named perichondrium. This, in its
use and structure, resembles the periosteum.
Where it covers the bones of the skull, it has
gotten the name of pericranium.
The periosteum is not a production of the dura
mater, as the ancients, and after them Havers,
imagined; nor are the bones formed by the ossi-
fication of this membrane, at least when it is in
a sound state, as some late writers have supposed.
The periosteum is deficient in the teeth above
the 

61
Part I. OSTEOLOGY.
the sockets, and in those parts of bones to which
ligaments or tendons are attached.
The MARROW is a fat oily substance, filling
the cavities of bones. In the great cavities of
long bones it is of much firmer consistence than
in the cells of their spongy part. In the former
it inclines somewhat to a yellowish tinge, and
is of the consistence of fat; in the latter it is
more fluid, and of a red colour. This diffe-
rence in colour and consistence is owing to ac-
cidental causes; both kinds are of the same na-
ture, and may both be described under the com-
mon name of marrow, though some writers give
the name only to the fat-like substance, and call
the other the medullary juice.
The marrow is contained in a very fine and
transparent membrane, which is supplied with a
great number of blood vessels, chiefly from the
periosteum. This membrana medullaris adheres
to the inner surface of the bones, and furnishes
an infinite number of minute bags or vesicles
for inclosing the marrow, which is likewise sup-
ported in the cavities of the bones by the long
filaments of their reticular substance.
Besides the vessels from the periosteum, the
membrana medullaris is furnished with others,
which in the long bones may be seen passing in
near the extremities of the bone, and sending off
numerous branches that ramify through all the
vesicles of this membrane.
The bones, and the cells containing the mar-
row 

62 
Part I. OSTEOLOGY. 
row, are likewise furnished with lymphatics. By
their means, the marrow, like the fat, may be
taken up in a greater quantity than it is secreted;
and hence it is that so little are found in the bones
of those who die of lingering diseases.
It is still a matter of controversy, Whether
the marrow is sensible or not? We are certain-
ly not able to trace any nerves to it; and from
this circumstance, and its analogy to fat, Haller
has ventured to consider it as insensible. On the
other hand, Duverney asserts, that an injury
done to this substance in a living animal was at-
tended with great pain. In this dispute physi-
ologists do not seem to have sufficiently discri-
minated between the marrow itself and the mem-
branous cells in which it is contained. The
former, like the fat, being nothing more than a
secreted, and of course an inorganized, matter,
may with propriety be ranked among the insensi-
ble parts, as much as inspissated mucus or any
other secreted matter in the body; whereas the
membrana medullaris being vascular, though it
possesses but an obscure degree of feeling in a
sound state, is not perfectly insensible.
The marrow was formerly supposed to be in-
tended for the nourishment and renewal of the
bones; but this doctrine is now pretty generally
and deservedly exploded. It seems probable that
the marrow is to the bones what fat is to the soft
parts. They both serve for some important pur-
poses in the animal œconomy; but their parti-
cular 

63
Part I. OSTEOLOGY.
cular use has never yet been clearly ascertained.
The marrow, from the transudation of the oil
through the bones of a skeleton, is supposed to
diminish their brittleness; and Havers, who
has written professedly on the bones, describes
the canals by which the marrow is conveyed
through every part of their substance, and di-
vides them into longitudinal and transverse ones.
He speaks of the first as extending through the
whole length of the bone; and of the latter, as
the passages by which the longitudinal ones com-
municate with each other. The similiarity of
these to the large cancelli in burnt bones, and
the transudation of the oil through the bones of
the skeleton, seems to prove that some such pas-
sages do actually exist.
The SYNOVIAL GLANDS are small bodies (D),
supposed to be of a glandular structure, and ex-
ceedingly vascular, secreting a fluid of a clear mu-
cilaginous nature, which serves to lubricate the
joints. They are placed in small cavities in the
articulations, so as to be capable of being gently
compressed by the motion of the joint, which ex-
presses their juice in proportion to the degree of
friction. When the synovia is wanting, or is of
too thick a consistence, the joint becomes stiff
and
(D) It is now much doubted, however, whether the ap-
pearances in the joints, which are usually called glands, are
any thing more than assemblages of fat.

64 
Part I. OSTEOLOGY. 
and incapable of flexion or extension. This is
what is termed anchylosis.
LIGAMENTS are white, glistening, inelastic
bands, of a compact substance, more or less
broad or thick, and serving to connect the bones
together. They are distinguished by different
names adapted to their different forms and uses.
Those of the joints are called either round or
bursal. The round ligaments are white, tendi-
nous, and inelastic. They are strong and flexi-
ble, and are found only in the joint of the knee,
and in the articulation of the os femoris with the
os innominatum. The bursal, or capsular liga-
ments, surround the whole joint like a purse, and
are to be found in the articulations which allow
motion every way, as in the articulation of the
arm with the scapula.
Of those sacs called BURSÆ MUCOSÆ, a few
were known to former anatomists, but by much
the greater number have been since discovered by
Dr. Monro (E), who observes, that they are to
be met with in the extremities of the body on-
ly; that many of them are placed entirely on
the inner sides of the tendons, between these
and the bones. Many others cover not only the
innner, but the outer sides of the tendons,
or are interposed between the tendons and
external parts, as  well as between those and the
bones.
3 Some
(E) See Description of the Bursæ Mucosæ, &c. 

65
Part I. OSTEOLOGY.
Some are situated between the tendons and ex-
ternal parts only or chiefly, some between con-
tiguous tendons, or between the tendons or the
ligaments and the joints. A few such sacs are
observed where the processes of bones play upon
the ligaments, or where one bone plays upon
another. Where two or more tendons are con-
tiguous, and afterwards separate from each other,
we generally find a common bursa divided into
branches, with which it communicates; and a
few bursæ of contiguous tendons communicate
with each other.—Some, in healthy children,
communicate with the cavities of the joints;
and in many old people be has seen such com-
munications formed by use or worn by friction,
independent of disease.
Their proper membrane is thin and transpa-
rent, but very dense and capable of confining
air or any other fluid. It is joined to the neigh-
bouring parts by the common cellular substance.
Betweeen the bursa and the hard substance of
bone, a thin layer of cartilage or of tough mem-
brane is very generally interposed. To the cel-
lular substance on the outside of the bursa, the
adipose substance is connected; except where
the bursa covers a tendon, cartilage, or bone,
much exposed to pressure or friction.
In several places a mass of fat, covered with
the continuation of the membrane of the bursa,
projects into its cavity. The edges of this are
divided into fringes.
E The 

66 
Part I. OSTEOLOGY. 
The inner side of the membrane is smooth,
and is extremely slippery from the liquor secret-
ed in it.
The structure of the bursæ bears a strong re-
semblance to the capsular ligaments of the joints.
1. The inner layer of the ligament, like that of
the bursæ, is thin and dense. 2. It is connected
to the external ligaments by the common cellu-
lar substance. 3. Between it and the bones, lay-
ers of cartilage, or the articular cartilages, are in-
terposed. 4. At the sides of the joints, where
it is not subject to violent pressure and friction,
the adipose substance is connected with the cel-
lular membrane. 5. Within the cavities of the
joints we observe masses of fat projecting, cover-
ed with similar blood-vessels, and with similar
fimbriæ hanging from their edges. 6. In the
knee the upper part of such a mass of fat forms
what has been called the mucilaginous gland of
the joint, and the under part projects into the
bursæ behind the ligament which ties the patella
to the tibia. 7. The liquor which lubricates the
bursæ has the same colour, consistence, and pro-
perties as that of the joints, and both are affected
in the same manner by heat, mineral acids, and
ardent spirits. 8. In some places the bursæ con-
stantly communicate with the cavities of the
joints, in others they generally do so; from
which we may infer a sameness of structure.
When we examine the fimbriæ common to
the fatty bodies of the joints and bursæ, and
which have been supposed to be the ducts of glands
lodged 

67
Part I. OSTEOLOGY.
lodged within the masses of fat, we are not able
to discover any glandular appearance within
them. And although we observe many vessels
dispersed upon the membranes of the fatty bo-
dies and fimbriæ; and that we cannot doubt that
these fimbriæ consist of ducts which contain a
lubricating liquor, and can even press such a li-
quor from them; yet their cavities and orifices
are so minute, that they are not discoverable
even by the assistance of magnifying-glasses.
These fimbriæ appear, therefore, to be ducts
like those of urethra, which prepare a mucila-
inous liquor without the assistance of any knotty
gr glandular organ.
Upon the whole, the synovia seems to be fur-
nished by invisible exhalent arteries by the ducts
of the fimbriæ, and by oil exuding from the adi-
pose follicles by passages not yet discovered.
The word skeleton, which by its etymology
simply implies a dry preparation, is usually ap-
plied to an assemblage of all the bones of an
animal united together in their natural order.
It is said to be a natural skeleton, when the bones
are connected together by their own proper li-
gaments; and an artificial one, when they are
joined by any other substance, as wire, &c.
The skeleton is generally divided into the
head, trunk, and  extremities. The first division
includes the bones of the cranium and face.
The bones of the trunk  are the spine, ribs, ster-
num, and bones of the pelvis.
E2 The

68 
Part I. OSTEOLOGY. 
The upper extremity on each side consists of
the two bones of the Shoulder, viz. the scapula
and clavicle; the bone of the arm, or os hu-
meri; the  bones of the fore-arm, and those
of the hand.
The lower extremity on each side of the trunk
consists of the thigh-bones and the bones of the
leg and foot.
SECT. II. Of the Bones of the Head.
The head is of a roundish figure, and some-
what oval (F). Its greatest diameter is from the
forehead to the occiput; its upper part is called
vertex, or crown of the head; its anterior or
fore-part the face; and the upper part of this
sinciput, or forehead; its sides the temples; its
posterior, or hind-part, the occiput; and its in-
ferior part the basis.
The bones of the head may be divided into
those of the cranium and face.
§ I Bones
(F) The bones of the fœtus being perfectly distinct, and
the muscles in young persons not acting much, the shape of
the head has been supposed to depend much on the manage-
ment of children when very young. Vesalius, who has
remarked the difference in people of different nations, ob-
serves, for instance, that the head of a Turk is conical,
from the early use of the turban; whilst that of an English-
man is flattened by the chin-stay. Some of the latest phy-
siologists suppose, with good reason, that this difference is
chiefly owing to certain natural causes with which we are as
yet unacquainted.

69
Part I. OSTEOLOGY.
§ I. Bones of the Cranium and face.
THERE are eight bones of the cranium, viz. the
coronal bone, or  os frontis; the two parietal
bones; or ossa bregmatis; the os occipitis; the
two temporal bones; the sphenoid bone; and the
os ethmoides, or cribriforme.
Of these, only the os occipitis and ossa breg-
matis are considered as proper to the cranium;
the rest being common both to the cranium and
face.
These bones are all harder at their surface than
in their middle; and on this account they are
divided into two tables, and a middle spongy
substance called diplöe.
Os Frontis. In this, as in all other bones, we
shall consider its figure, structure, processes, de-
pressions and cavities; and the manner in which
it is articulated with the other bones.
The os frontis has some resemblance in shape
to the shell of the cockle. Externally it is con-
vex, its concave side being turned towards the
brain. This bone, in the places where it is uni-
ted to the temporal bones, is very thin, and has
there no diplöe. It is likewise exceedingly thin
in that  part of the orbit of the eye which is
nearest to the nose. Hence it is, that a wound
in the eye, by a sword or any other pointed in-
strument, is sometimes productive of immedi-
ate death. In these cases,the sword passing through
the 

70
Part I. OSTEOLOGY.  
the weak part of the bone, penetrates the brain,
and divides the nerves at their origin; or per-
haps opens some blood-vessel, the consequences
of which are soon fatal.
We observe on the exterior surface of this
bone five apophyses or processes, which are ea-
sily to be distinguished. One of these is placed
at the bottom and narrowest part of the bone,
and is called the nasal process, from its support-
ing the upper end of the bones of the nose.
The four others are called angular or orbitar pro-
cesses. They assist to form the orbits, which
are the cavities on which the eyes are placed. In
each of these orbits there are two processes, one
at the interior or great angle, and the other at
the exterior or little angle of the orbit. They
are called the angular processes. Between these
a ridge is extended in form of an arch, and on
this the eye-brows are placed. It is called the
orbitar or superciliary ridge, and in some mea-
sure covers and defends the globe of the eye.
There is a hole in this for the passage of the
frontal vessels and nerves. This arch is inter-
rupted near the nose by a small pit, in which the
tendon of the musculus obliquus major of the
eye is fixed. From the under part of each su-
perciliary ridge a thin plate runs a considerable
way backwards, and has the name of orbitar;
the external and fore-part of this plate forms a
sinuosity for lodging the lacrymal gland. Between
the orbitar plates there is a large discontinuation
of 

71
Part I. OSTEOLOGY.
of the bone, which is filled up by the cribriform
part of the os ethmoides.
On examining the inner surface of this bone
at its under and middle part, we observe an ele-
vation in form of a ridge, which has been called
the spinous process; it ascends for some way, di-
viding the bone into two considerable fossæ, in
which the anterior lobes of the brain are placed.
To a narrow furrow in this ridge is attached the
extremity of the falx, as the membrane is called,
which divides the brain into two hemispheres.
The furrow becoming gradually wider, is conti-
nued to the upper and back part of the bone. It
has the falx fixed to it, and part of the longitudi-
nal sinus lodged in it. Besides the two fossæ,
there are many depressions, which appear like
digital impressions, and owe their formation to
the prominent circumvolutions of the brain.
In the fœtus, the forehead is composed of two
distinct bones; so that in them the sagittal suture
reaches from the os occipitis to the nose. This
bone is almost every where composed of two ta-
bles and a diplöe. These two tables separating
from each other under the eyes, form two cavi-
ties, one on each side of the face, called the
frontal sinuses. These sinuses are lined with a
soft membrane, called membrana pituitaria. In
these sinuses a mucus is secreted, which is con-
stantly passing through two small holes into the
nostrils, which it serves to moisten.
The os frontis is joined by future to many of
the 

72 
OSTEOLOGY. Part I.
the bones of the head, viz. to the parietal, max-
illary, and temporal bones; to the os ethmoides;
os sphenoides; os unguis; and ossa nasi. The
suture which connects it with the parietal bones
is called the coronal suture.
The PARIETAL BONES are two in number;
they are very thin, and even transparent in some  
places. The particular figure of each of these
bones is that of an irregular square, bordered with
indentations through its whole circumference, ex-
cept at its lower part. It will be easily conceiv-
ed, that these bones which compose the superior
and lateral parts of the cranium, and cover the
greatest part of the brain, form a kind of vault.
On their inner surface we observe the marks of
the vessels of the dura mater; and at their up-
per edge the groove for the superior longitudinal
sinus.
The ossa parietalia are joined to each other
by the sagittal future; to the os sphenoides
and ossa temporum by the squamous suture;
to the os occipitis by the lambdoidal suture (A),
so called from its resemblance to the Greek letter
lambda; and to the os frontis by the coronal sut-
ture.
In the fœtus, the parietal bones are separated
from the middle of the divided os frontis by a
portion of the cranium then unossified.
The
(A) The lambdoidal suture is sometimes very irregular, be-
ing composed of many small sutures, which surround so many
little bones called ossa triquetra, though perhaps improperly,
as they are not always triangular.

73
Part I. OSTEOLOGY.
The occipital bone forms the posterior
and inferior parts of the skull; it approaches
nearly to the shape of a lozenge, and is indented
throughout three parts of its circumference.
There is a considerable hole in the inferior
portion of this bone, called the foramen magnum,
through which the medulla oblongata passes into
the spine. The nervi accessorii, and vertebral
arteries, likewise pass through it. Behind the
condyles are two holes for the passage of cervical
veins into the lateral sinuses; and above them
are two others for the passage of the eighth pair
and accessory nerves out of the head. At the
sides, and a little on the anterior part of the fora-
men magnum, are two processes, called the con-
dyles, one on each side; they are of an oval fi-
gure, and are covered with cartilage.
The external surface of this bone has a large
transverse arched ridge, under which the bone is
very irregular, where it affords attachment to se-
veral muscles. On examining its inner surface,
we may observe two ridges in form of a cross;
one ascending from near the foramen magnum to
the top of the bone; the upper end of this in
which the falx is fixed, is hollow, for lodging
the superior longitudinal sinus, and the under end
has the third process of the dura mater fixed to
it. The other ridge, which runs horizontally,
is likewise hollow for containing the lateral sinuses.
Four fossæ are formed by the cross, two above
and two below. In the former are placed the pos-
terior                                                                                                                     

74 
Part I. OSTEOLOGY. 
terior lobes of the brain, and in the latter the lobes
of the cerebellum.
At the basis of the cranium, we observe the
cuneiform process (which is the name given to
the great apophysis at the fore part of this bone);
it serves for the reception of the medulla oblon-
gata.
The os occipitis is of greater strength and
thickness than either of the other bones of the
head, though irregularly so: at its inferior part,
where it is thinnest, it is covered by a great num-
ber of muscles.
This bone, from its situation, being more lia-
ble to be injured by falls, than any other bone
of the head, nature has wisely given it the greatest
strength at its upper part, where it is most expos-
ed to danger.
It is joined to the parietal bones by the lamb-
doidal suture, and to the ossa temporum, by the
additamentum of the temporal suture. It is like-
wise connected to the os sphenoides by the cunei-
form process. It is by means of the os occipitis
that the head is united to the trunk, the two con-
dyles of this bone being connected to the supe-
rior oblique processes of the first vertebra of the
neck.
There are two temporal bones, one on each
side.—We may distinguish in them two parts;
one of which is called the squamous or scaly part,
and the other pars petrosa from its hardness. This
last is shaped like a pyramid.
Each 

75
Part I. OSTEOLOGY. 
Each of these divisions affords processes and ca-
vities: externally there are three processes; one
anterior, called the zygomatic process, one pos-
terior, called the mastoid or mamillary process,
from its resemblance to a nipple; and one infe-
rior, called the syloid process, because it is shaped
like a stiletto, or dagger.
The cavities are, 1. The meatus auditorius ex-
ternus. 2. A large fossa which serves for the ar-
ticulation of the lower jaw; it is before the mea-
tus auditorius, and immediately under the zygo-
matic  process. 3. The stylo-mastoid hole, so
called from its situation between the styloid and
mastoid processes; it is likewise styled the aquæ-
duct of Fallopius, and affords a passage to the
portio dura of the auditory, or seventh pair of
nerves. 4. Below, and on the fore-part of the
last foramen, we observe part of the jugular fossa,
in which the beginning of the internal jugular
vein is lodged. Anterior and superior to this
fossa is the orifice of a foramen, through which
passes the carotid artery. This foramen runs first
upwards and then forwards, forming a kind of
elbow, and terminates at the end of the os pe-
trosum.—At this part of each temporal bone, we
may observe the opening of the Eustachian tube,
a canal which passes from the ear to the back part
of the nose.
In examining the internal surface of these
bones, we may remark the triangular figure of
their petrous part which separates two fossæ; one
superior 

76 
Part I. OSTEOLOGY.  
superior and anterior; the other inferior and
posterior: the latter of these composes part of
the fossa, in which the cerebellum is placed;
and the former, a portion of the least fossa for
the basis of the brain. On the posterior side of
the pars petrosa, we observe the meatus auditorus
internus, into which enters the double nerve of
the seventh pair. On the under side of this pro-
cess, part of a hole appears, which is common
to the temporal and occipital bones; through it
the lateral sinus, the eighth pair, and accessory
nerves, pass out of the head.
The pars petrosa contains several little bones
called the bones of the ear; which, as they do
not enter into the formation of the cranium, shall
be described when we are treating of the organs
of hearing.
The ossa temporum are joined to the ossa ma-
larum, by the zygomatic sutures; to the pa-
rietal bones, by the squamous sutures; to the
os occipitis, by the lambdoidal suture; and to
the sphenoid bone, by the suture of that name.
Os sphenoides. This bone, from its situation
amidst the other bones of the head, has sometimes
been called cuneiforme. It is of a very irregular
figure, and has been compared to a bat with its
wings extended.     
It is commonly divided into its middle part or
body, and its sides or wings.
The fore part of the body has a spine or ridge,
which makes part of the septum narium. The
upper 

77
Part I. OSTEOLOGY.
upper part of each wing forms a share of the
temple. The fore part of this belongs to the or-
bit; while the under and back part, termed
spinous process, is lodged in the base of the skull
at the point of the pars petrosa. But two of the
most remarkable processes are the ptergoid or ali-
form, one on each side of the body of the bone,
and at no great distance from it. Each of these
processes is divided into two wings, and of these
the exterior one is the widest. The other ter-
minates in a hook-like process.
The internal surface of this bone affords three
fossæ. Two of these are formed by the wings
of the bone, and make a part of the lesser fossæ
of the basis of the cranium. The third, which
is smaller, is on the top of the body of the bone;
and is called sella turcica, from its resemblance
to a Turkish saddle. This fossa, in which the
pituitary gland is placed, has posteriorly and an-
teriorly processes called the clinoid processes.
There are twelve holes in this bone, viz. six
on each side. The first is the passage of the op-
tic nerve and ocular artery; the second, or large
slit, transmits the third, fourth, sixth, and first
part of the fifth pair of nerves with the ocular
vein; the third hole gives passage to the second
branch of the fifth pair; and the fourth hole to
the third branch of the fifth pair of nerves. The
fifth hole is the passage of the artery of the dura
mater. The sixth hole is situated above the
ptergoid process of the sphenoid bone; through
it 

78 
Part I. OSTEOLOGY. 
it a reflected branch of the second part of the
fifth pair passes.
Within the substance of the os sphenoides there
are two sinuses separated by a bony plate. They
are lined with the pituitary membrane; and,
like the frontal sinuses, separate a mucus which
passes into the nostrils.
The os sphenoides is joined to all the
bones of the cranium; and likewise to the
ossa maxillaria, ossa malarum, ossa palati, and
vomer.
This bone makes part of the basis of the skull,
assists in forming the orbits, and affords attach-
ment to several muscles.
The os ethmoides is situated at the fore part of
the basis of the cranium, and is of a very irre-
gular figure. From the great number of holes
with which it is pierced, it is sometimes called os
cribriforme or sieve-like bone
The os ethmoides or cribriforme consists of a
middle part and two sides. The middle part is
formed of a thin bony plate, in which are an
infinite number of holes that afford a passage to
filaments of the olfactory nerve. From the mid-
dle of this plate, both on the outside and from
within, there rises up a process, which may be
easily distinguished. The inner one is called
crista galli, from its supposed resemblance to a
cock's comb. To this process the falx of the
dura mater is attached. The exterior process,
which has the same common basis as the crista
galli, 

79
Part I. OSTEOLOGY.
galli, is a fine lamella which is united to the
vomer; and divides the cavity of the nostrils,
though unequally, it being generally a little in-
clined to one side.
The lateral parts of this bone are composed
of a cellular substance; and these cells are so ve-
ry intricate, that their figure or number cannot
be described. Many writers have on this account
called this part of the bone the labyrinth. These
cells are externally covered with a very thin bony
lamella. This part of the bone is called the os
planum, and forms part of the orbit.
The different cells of this bone, which are
numerous, and which are every where lined with
the pituitary membrane, evidently serve to en-
large the cavity of the nose, in which the organ
of smelling resides.
This bone is joined to the os sphenoides, os
frontis, ossa maxillaria, ossa palati, ossa nasi, ossa
unguis, and vomer.
The ancients, who considered the brain as the
seat of all the humours, imagined that this viscus
discharged its redundant moisture through the
holes of the ethmoid bone. And the vulgar still
think, that abscesses of the brain discharge them-
selves through the mouth and ears, and that snuff
is liable to get into the head; but neither snuff
nor the matter of an abscess are more capable of
passing through the cribriform bone, than the
serosity which they supposed was discharged
through it in a common cold.—All the holes of
the 

80 
Part I. OSTEOLOGY. 
the ethmoid bone are filled up with the branches
of the olfactory nerve. Its inner part is likewise
covered with the dura mater, and its cells are
every where lined with the pituitary membrane;
so that neither matter nor any other fluid can
possibly pass through this bone either externally
or internally. Matter is indeed sometimes dis-
charged through the nostrils; but the seat of the
disease is in the sinuses of the nose, and not in
the brain; and imposthumations are observed to
take place in the ear, which suppurate and dis-
charge themselves externally.
Before we leave the bones of the head, we wish
to make some general observations on its struc-
ture and figure. As the cranium might have
been composed of a single bone, the articulation
of its several bones being absolutely without mo-
tion, it may be asked perhaps, Why such a mul-
tiplicity of bones, and so great number of su-
tures? Many advantages may possibly arise from
this plurality of bones and sutures, which may
not yet have been observed. We are able, how-
ever, to point out many useful ends, which could
only be accomplished by this peculiarity of struc-
ture.—In this, as in all the other works of na-
ture, the great wisdom of the Creator is evinced,
and cannot fail to excite our admiration and gra-
titude.
The cranium, by being divided into several
bones, grows much faster and with greater faci-
lity, than if it was composed of one piece only.
3 In


81
Part I. OSTEOLOGY.
In the fœtus, the bones, as we have before ob-
served, are perfectly distinct from each other.
The ossification begins in the middle of each
bone, and proceeds gradually to the circumfer-
ence. Hence the ossification, and of course the
increase of the head, is carried on from an infi-
nite number of points at the same time, and the
bones consequently approach each other in the
same proportion. To illustrate this doctrine
more clearly, if it can want further illustration,
suppose it necessary for the parietal bones which
compose the upper part of the head, to extend
their ossification, and form the fore part of the
head likewise.—Is it not evident, that this pro-
cess would be much more tedious than it is now,
when the os frontis and the parietal bones are
both growing at the same time? Hence it hap-
pens, that the heads of young people, in which
the bones begin to touch each  other, increase
slowly; and that the proportionate increase of
the volume of the head is greater in three months
in the fœtus, than it is perhaps in twenty-four
months at the age of fourteen or fifteen years.
The sutures, exclusive of their advantage in
suspending the processes of the dura mater, are
evidently of great utility in preventing the too
great extent of fractures of the skull.—Suppose,
for instance, that by a fall or blow, one of the
bones of the cranium becomes fractured. The
fissure, which in a head composed of only one
bone, would be liable to extend itself through
F the


82 
Part I. OSTEOLOGY. 
the whole of it, is checked, and sometimes per-
haps stopped by the first suture it meets, and the
effects of the injury are confined to the bone on
which the blow was received. Ruysch indeed,
and some others, will not allow the sutures to be
of any such use; but cases have been met with
where they seemed to have had this effect, and
in young subjects their utility in this respect must
be still more obvious.
The spherical shape of the head seems likewise
to render it more capable of resisting external vi-
olence than any other shape would do. In a
vault, the parts mutually support and strengthen
each other, and this happens in the cranium.
§ 2. Proper Bones of the Face.
THE FACE, which consists of a great num-
ber of bones, is commonly divided into the up-
per and lower jaws. The upper jaw consists of
thirteen bones, exclusive of the teeth. Of these,
six are placed on each side of the maxilla superior,
and one in the middle.
The bones, which are in pairs, are the ossa
malarum, ossa maxillaria, ossa nasi, ossa unguis,
ossa palati, and ossa spongiosa inferiora. The
single bone is the vomer.
The ossa malarum are the prominent square
bones which are placed under the eyes, forming
part of the orbits and the upper part of the cheeks.
Each of them affords three surfaces; one exte-
rior and a little convex; a second superior and
concave,

83
Part I. OSTEOLOGY.
concave, forming the inferior part and sides of
the orbit; and a third posterior, irregular, and
hollowed for the lodgement of the lower part of
the temporal muscle.
The angles of each bone form four processes,
two of which may be called orbitar processes; of
these the upper one is joined by suture to the os
frontis, and that below to the maxillary bone.
The third is connected with the os sphenoides
by means of the transverse suture; and the fourth
is joined to the zygomatic process of the tempo-
ral bone, with which it forms the zygoma.
The ossa maxillaria superiora. These bones,
which are of a very irregular figure, are so called
because they form the most considerable por-
tion of the upper jaw. They are two in
number, and generally remain distinct through
life.
Of the many processes which are to be seen
on these bones, and which  are connected with
the bones of the face and skull, we shall describe
only the most remarkable.
One of these processes is at the upper and fore
part of the bone, making part of the side of the
nose, and called the nasal process. Another forms
a kind of circular sweep at the inferior part of the
bone, in which are the alveoli or sockets for the
teeth: this is called the alveolar process. A third
process is united to the os malæ on each side. Be-
tween this and the nasal process there is a thin
plate, which forms a Share of the orbit, and lies
F2 over


84 
Part I. OSTEOLOGY.  
over a passage for the superior maxillary vessels
and nerves.—The alveolar process has posteriorly
a considerable tuberosity on its internal surface,
called the maxillary tuberosity.
Behind the alveolar process we observe two
horizontal lamellæ, which uniting together, form
a part of the roof of the mouth, and divide it
from the nose. The hollowness of the roof of
the mouth is owing to this partition's being seat-
ed somewhat higher than the alveolar process.—
At the fore part of the horizontal lamellæ there
is a hole called foramen incisivum, through which
small blood-vessels and nerves go between the
mouth and nose.
In viewing these bones internally, we ob-
serve a fossa in the inferior portion of the nasal
process, which, with the os unguis and os spon-
giosum inferius, forms a passage for the lachrymal
duct.
Where these two bones are united to each
other, they  project somewhat upwards and for-
wards, leaving between them a furrow, into
which the lower portion of the septum nasi is
admitted.
Each of these bones being hollow, a consider-
able sinus is formed under its orbitar part. This
cavity, which is usually named after Highmore,
though it was described by Fallopius and others
before his time, is lined with the pituitary mem-
brane. It is intended for the same purposes as
the 

85
Part I. OSTEOLOGY.
the other sinuses of the nose, and opens into the
nostrils.
The ossa maxillaria are connected with the
greater part of the bones of the face and crani-
um, and assist in forming not only the cheeks,
but likewise the palate, nose, and orbits.
The ossa nasi form two irregular squares. They
are thicker and narrower above than below. Ex-
ternally they are somewhat convex, and inter-
nally slightly concave. These bones constitute
the upper part of the nose. At their fore part
they are united to each other, above to the os
frontis, by their sides to the ossa maxillaria supe-
riora, posteriorly and interiorly to the septum na-
rium, and below to the cartilages that compose
the rest of the nostrils.
The ossa unguis. These little transparent
bones owe their name to their supposed resem-
blance to a finger-nail. Sometimes they are
called ossa lachrymalia, from their concurring
with the nasal process of each maxillary bone
in forming a lodgement for the lachrymal sac and
duct.
The ossa unguis are of an irregular figure.
Their external surface consists of two smooth
parts, divided by a middle ridge. One of these
parts, which is concave and nearest to the nose,
serves to support the lachrymal sac and part of the
lachrymal duct. The other, which is flat, forms
a small part of the orbit.
Each 

86 
Part I. OSTEOLOGY.  
Each of these bones is connected with the
os frontis, os ethmoides, and os maxillare su-
perius.
The ossa palati. These bones, which are si-
tuated at the back part of the roof of the mouth,
between the os sphenoides and the ossa maxillaria
superiora, are of a very irregular shape, and serve
to form the nasal and maxillary fossa, and a small
portion of the orbit. Where they are united to
each other, they rise up into a spine on their in-
ternal surface. This spine appears to be a con-
tinuation of that of the superior maxillary bones,
and helps to form the septum narium.
These bones are joined to the ossa maxillaria
superiora, os ethmoides, os sphenoides, and vo-
mer.
The vomer. This bone derives its name from
its resemblance to a ploughshare. It is a long
and flat bone, somewhat thicker at its back than
at its fore part. At its upper part we observe a
furrow extending through its whole length. The
posterior and largest part of this furrow receives
a process of the sphenoid bone. From this the
furrow advances forwards, and becoming nar-
rower and shallower, receives some part of the
nasal lamella ethmoidea; the rest serves to sup-
port the middle cartilage of the nose.
The inferior portion of this bone is placed on
the nasal spine of the maxillary and palate bones,
which we mentioned in our description of the
ossa palati.
The

87
Part I. OSTEOLOGY.
The vomer is united to the os sphenoides, os
ethmoides, ossa maxillaria superiora, and ossa
palati. It forms part of the septum narium,
by dividing the back part of the nose into two
nostrils.
The ossa spongiosa inferiora. The parts which
are usually described by this name, do not seem
to deserve to be distinguished as distinct bones,
except in young subjects. They consist of a
spongy lamella in each nostril, which is united
to the Spongy lamina of the ethmoid bone, of
which they are by some considered as a part.
Each of these lamellæ is longest from be-
hind forwards; with its convex surface turn-
ed towards the septum narium, and its con-
cave part towards the maxillary bone, co-
vering the opening of the lachrymal duct into
the nose.
These bones are covered with the pituita-
ry membrane; and, besides their connection
with the ethmoid bone, are joined to the ossa
maxillaria superiora, ossa palati, and ossa un-
guis.
The maxilla inferior, or lower jaw, which in
its shape resembles a horse-shoe, consists of two
distinct bones in the fœtus; but these unite to-
gether soon after birth, so as to form only one
bone. The upper edge of this bone, like the os
maxillare superius, has an alveolar process, fur-
nished with sockets for the teeth.
On 

88 
Part I. OSTEOLOGY. 
On each side, the posterior part of the bone
rises almost perpendicularly into two processes,
The highest of these called the coronoid process,
is pointed and thin, and serves for the insertion
of the temporal muscle. The other, or condy-
loid process, as it is called, is shorter and thicker,
and ends in an oblong rounded head, which is
received into a fossa os the temporal bone, and
is formed for a moveable articulation with the
cranium. This joint is furnished with a move-
able cartilage. At the bottom of each coronoid
process, on its inner part, we observe a foramen
extending under the roots of all the teeth, and
terminating at the outer surface of the bone near
the chin. Each of these canals transmits an ar-
tery, vein, and nerve, from which branches are
sent off to the teeth.
The lower jaw is capable of a great variety of
motion. By sliding the condyles from the cavi-
ty towards the eminences on each side, we bring
it horizontally forwards, as in biting; or we
may bring the condyles only forward, and tilt the
rest of the jaw backward, as in opening the
mouth. We are likewise able to slide the con-
dyles alternately backwards and forwards, from
the cavity to the eminence, and vice versa, as
in grinding the teeth. The cartilages, by adapt-
ing themselves to the different inequalities in
these several motions of the jaw, serve to secure
the articulation, and to prevent any injuries from
friction.
The

89
Part I. OSTEOLOGY.
The alveolar processes are composed of an
outer and inner bony plate, united together by
thin partitions, which at the fore part of the
jaw divide the processes into as many sockets as
there are teeth. But at the back part of the jaw,
where the teeth have more than one root, we
find a distinct cell for each root. In both jaws
these processes begin to be formed with the
teeth; they likewise accompany them in their
growth, and gradually disappear when the teeth
are removed.
§ 3. Of the Teeth.
THE TEETH are bones of a particular structure,
formed for the purposes of mastication and the
articulation of the voice. It will be necessary to
consider their composition and figure, their num-
ber and arrangement, and the time and order in
which they appear.
In each tooth we may distinguish a body, a
neck, and a root or fangs.
The body of the tooth is that part which ap-
pears above the gums. The root is fixed into
the socket, and the neck is the middle part be-
tween the two.
The teeth are composed of two substances,
viz. enamel  and bone. The enamel, or the vi-
terous or cortical part of the tooth, is a white and
very hard and compact substance peculiar to the
teeth, and appears fibrous or striated when broken.
This substance is thickest on the grinding sur-
face,

90 
OSTEOLOGY. Part I.
face, and becoming gradually thinner, terminates
insensibly at the neck  of the tooth. Ruysch *
affirmed, that he could trace the arteries into the
hardest part of the teeth; Liewenhoeck † sus-
pected the fibres of the enamel to be so many
vessels : and Monro ‡ says, he has frequently in-
jected the vessels of the teeth in children, so as
to make the inside of the cortex appear perfectly
red. But it is certain, that it is not tinged by a
madder diet; and that no injection will ever
reach it, so that it has no appearance of being
vascular §.
The bony part, which composes the inner
substance of the body, neck, and root of the
tooth, resembles other bones in its structure, but
it is much harder than the most compact part
of bones in general. As a tooth when once
formed receives no tinge from a madder diet,
and as the minutest injections do not penetrate
into its substance, this part of the tooth has, like
the enamel, been supposed not to be vascular.
But when we consider that the fangs of a tooth
are inverted by a periosteum, and that the swell-
ings of these fangs are analogous to the swellings
of other bones, we may reasonably conclude,
that there is a similarity of structure ; and that
this bony part has a circulation through its sub-
stance,
* The saur 10. no. 27.
† Arcan. Natur. continuat. Epistol.
‡ Anat. of the Human Bones.
§ Hunter on the Teeth.

91
Part I. OSTEOLOGY.
stance, although from its hardness we are unable
to demonstrate its vessels.
In each tooth we find an inner cavity, into
which enter an artery, vein, and nerve. This
cavity begins by a small opening, and becoming
larger, terminates in the body of the tooth. In
advanced life this hole sometimes closes, and the
tooth is of course rendered insensible.
The periosteum surrounds the teeth from their
fangs to a little beyond their bony sockets, where
we find it adhering to the gums. This mem-
brane, while it incloses the teeth, serves at the
same time to line the sockets, So that it may be
considered as common to both.
The teeth are likewise secured in their sock-
ets by means of the gums; a red, vascular, firm,
and elastic substance, that possesses but little sen-
sibility. In the gums of infants we find a hard
ridge extending through their whole length, but
no such ridge is to be seen in old people who
have lost their teeth.
The number of the teeth in both jaws at full
maturity, usually varies from twenty-eight to
thirty-two. They are commonly divided into
three classes, viz. incisores, canini, and grind-
ers or molares (H). The incisores are the four
teeth in the fore part of each jaw. They have
each
(H) Mr. Hunter has thought proper to vary this division.
He retains the old name incisores to the four fore teeth, but
he distinguishes the canine teeth by the name of the cuspidati.
The 

92 
Part I. OSTEOLOGY. 
each of them two surfaces; one anterior and
convex, the other posterior and slightly concave,
both of which terminate in a sharp edge. They
are called incisores from their use in dividing the
food. They are usually broader and thicker in
the upper than in the under jaw; and, by be-
ing placed somewhat obliquely, generally fall
over the latter.
The canini derive their name from their re-
semblance to a dog's tusks, being the longest of
all the teeth. We find one on each side of the
incisores, so that there are two canini in each
jaw. Their fang resembles that of the incisores,
but is much larger; and in their shape they appear
like an incisor with its edge worn off, so as to
terminate in a narrow point.
These teeth not being calculated for cutting
and dividing the food like the incisores, or for
grinding it like the molares, seem to be intend-
ed for laying hold of substances (I).
The molares or grinders, of which there are
ten in each jaw, are so called, because from their
shape and size they are fitted for grinding the
food. Each of the incisores and canini is fur-
nished
The two teeth which are next to these, and which have been
usually ranked with the molares, he calls the bicuspides; and
he gives the name of grinders only to the three last teeth on
each side.
(I) Mr. Hunter remarks of these teeth, that we may trace
in them a similarity in shape, situation, and use, from the
most imperfectly carnivorous animal, which we believe to be
the human species, to the lion, which is the most perfectly
carnivorous.

93
Part I. OSTEOLOGY.
nished only with one fang; but in the molares
of the under jaw we constantly find two fangs,
and in those of the upper jaw three fangs. These
fangs are sometimes separated into two points,
and each of these points has sometimes been de-
scribed as a distinct fang.
The two first of the molares, or those near-
est to the canine teeth on each side, differ from
the other three, and are with great propriety
named bicuspides by Mr. Hunter. They have
sometimes only one root, and seem to be of a
middle nature between the incisores and the
larger molares. The two next are much larger.
The fifth or last grinder on each side is smaller
and shorter than the rest; and from its not cut-
ting the gum till after the age of twenty, and
sometimes not till much later in life, is called
dens sapientiæ.
There is in the structure and arrangement of
all these teeth an art which cannot be sufficiently
admired. To understand it properly, it will be
necessary to consider the under jaw as a kind of
lever, with its fixed points at its articulations with
the temporal bones:—it will be right to observe,
too, that its powers arise from its different mus-
cles, but in elevation chiefly from the tempora-
lis and masseter; and that the aliment constitutes
the object of resistance. It will appear, then,
that the molares, by being placed nearest the cen-
tre of motion, are calculated to press with a much
greater force than the other teeth, independent
of their grinding powers which they possess by
means 

94 
Part I. OSTEOLOGY. 
means of the pterygoid muscles; and that it is
for this reason we put between them any hard
body we wish to break.
The canini and incisores are placed farther
from this point, and of course cannot exert so
much force; but they are made for cutting and
tearing the food, and this form seems to make
amends for their deficiency in Strength.
There are examples of children who have
come into the world with two, three, and even
four teeth; but these examples are very rare;
and it is seldom before the seventh, eighth, or
ninth month after birth, that the incisores, which
are the first formed, begin to pass through the
gum. The Symptoms of dentition, however,
in consequence of irritation from the teeth, fre-
quently take place in the fourth or fifth month.
About the twentieth or twenty-fourth month,
the canini and two molares make their appear-
ance.
The dangerous symptoms that sometimes ac-
company dentition, are owing to the pressure
of the teeth on the gum, which they irritate so
as to excite pain and inflammation. This irri-
tation seems to occasion a gradual wasting of the
gum at the part, till at length the tooth makes its
appearance.
The symptoms are more or less alarming, in
proportion to the resistance which the gum
affords to the teeth, and according to the number
of teeth which may chance to seek a passage at the
same 

95
Part I. OSTEOLOGY.
same time. Were they all to appear at once,
children would fall victims to the pain and ex-
cessive irritation; but nature has so very wisely
disposed them, that they usually appear one af-
ter the other, with some distance of time between
each. The first incisor that appears is generally
in the lower jaw, and is followed by one in the
upper jaw. Sometimes the canini, but more
commonly one of the molares, begins to pass
through the gum first.
These 20 teeth, viz. eight incisores, four ca-
nini, and eight molares, are called temporary or
milk teeth, because they are all shed between the
age of seven and fourteen, and are succeeded by
what are called  the permanent or adult teeth.
The latter are of a firmer texture, and have
larger fangs.
These adult teeth being placed in a distinct set
of alveoli, the upper sockets gradually disappear,
as the under ones increase in size, till at length.
the temporary, or upper teeth, having no longer
any Support, consequently fall out.
To these 20 teeth, which succeed the tempo-
rary ones, 12 others are afterwards added, viz.
three molares on each side in both jaws : and in
order to make room for this addition, we find
that the jaws gradually lengthen in proportion
to the growth of the teeth; so that with 20 teeth,
they seem to be as completely filled as they are
afterwards with 32. This is the reason why
3 the
 

96 
Part I. OSTEOLOGY.  
the face is rounder and and flatter in children than
in adults.
With regard to the formation of the teeth, we
may observe, that in a fœtus of four months, the
alveolar process appears only as a shallow longi-
tudinal groove, divided by minute ridges into a
number of intermediate depressions; in each of
which we find a small pulpy substance, surround-
ed by a vascular membrane. This gradually
ossifies, and its lower part is lengthened out to
form the fang. When the bony part of the
tooth is formed, its surface begins to be incrust-
ed with the enamel. How the latter is formed
and deposited, we are not yet able to determine.
The rudiments of some of the adult teeth be-
gin to be formed at a very early period, for the
pulp of one of the incisores may generally be
perceived in a fœtus of eight months, and the
ossification begins in it soon after birth. The
first bicuspis begins to ossify about the fifth or
sixth, and the second about the seventh year.
The first adult grinder cuts the gum about the
12th, the second about the 18th, and the third,
or dens sapientiæ, usually between the 20th and
30th year.
The teeth, like other bones, are liable to be
affected by disease. Their removal is likewise
the natural consequence of old age ; for as we
advance in life, the alveoli fill up, and the teeth,
especially the incisores, fall out. When this hap-
pens.

97
Part I. OSTEOLOGY.
pens, the chin projects forward, and the face is
much shortened.
§ 4. Of the Os Hyoides. (K)
The os hyoides, which is placed at the root
of the tongue, was so called by the the ancients
on account of its supposed resemblance to the
Greek letter υ.
It will be necessary to distinguish in it, its bo-
dy, horns, and appendices.
The body, which is the middle and broadest
part of the bone, is so placed that it may be ea-
sily felt at the fore part of the throat. Anteri-
orly it is irregularly convex, and its inner sur-
face is unequally concave. Its cornua, or horns,
which are flat and a little bent, being much longer
than the body part, may be described as forming
the sides of the υ. The appendices, or little
horns, as they are called by M. Winslow, and
some other writers, are two processes which rise
up from the articulations of the cornua with the
body, and are usually connected with the sty-
loid process on each side by means of a liga-
ment.
G The
(K) This bone is very seldom preserved with the skeleton,
and cannot be included among the bones of the head, or inany
other division of the skeleton. Thomas Bartholin has per-
haps very properly described it among parts contained in the
mouth; but the generality of anatomical writers have plac-
ed it, as it is here, after the bones of the face. 

98 
Part I. OSTEOLOGY.
The uses of this bone are to support the tongue,
and afford attachment to a great number of mus-
cles; some of which perform the motions of
the tongue, while others act on the larynx and
fauces.
Sect. III. Of the Bones of the Trunk.
The trunk of the skeleton consists of the
spine, the thorax, and the pelvis.
§ 1. Of the Spine.
The spine is composed of a great number of
bones called vertrebæ, forming a long bony co-
lumn, in figure not much unlike the letter s.
This column, which extends from the head to
the lower part of the body, may be said to con-
sist of two irregular and unequal pyramids, uni-
ted to each other in that part of the loins where
the last lumbar vertebra joins the os sacrum.
The vertebrae of the upper and longest pyra-
mid are called true vertebræ, in contradistinction
to those of the lowermost pyramid, which, from
their being immoveable in the adult, are
styled false vertebræ. It is upon the bones of the
spine that the body turns; and it is to this cir-
cumstance they owe their name, which is deriv-
ed from the Latin verb vertere, to turn.
The true vertebræ are divided into three classes
of cervical, dorsal, and lumbar vertebræ.—The
false 

99
Part I. OSTEOLOGY.
false vertebræ consist of the os sacrum and os oc-
cygis.
In each vertebra, as in other bones, it will be
necessary to remark the body of the bone, its pro-
cesses, and cavities.
The body, which is convex before, and con-
cave behind, where it assists in forming the ca-
vity of the spine, may be compared to part of a
cylinder cut off transversely.
Each vertebra affords seven processes. The
first is at the back part of the vertebra, and from
its shape and direction is named the spinous pro-
cess. On each side of this are two others, which,
from their situation with respect to the spine,
are called transverse processes. The four others
are styled oblique or articular processes. They
are much smaller than the spinous or transverse
ones. Two of them are placed on the upper,
and two on the lower part of each vertebra, ri-
sing from near the basis of each transverse pro-
cess. They have gotten the name of oblique pro-
cesses, from their situation with respect to the
processes with which they are articulated; and
they are sometimes styled articular processes, from
the manner in which they are articulated with
each other; the two superior processes of one
vertebra being articulated with the two other in-
ferior processes of the vertebra above it. Each
of these processes is covered with cartilage at its
articulation, and their articulations with each
other are by a species of ginglimus.
G2 In


100 
Part I. OSTEOLOGY. 
In each vertebra, between its body and its
processes, we find a hole large enough to admit
a linger. These holes or foramina, correspond
with each other through all the vertebrae, and
form the long bony channel in which the spinal
marrow is placed. We may likewise observe
four notches in  each vertebra. Two of these
notches are at the upper, and two at the lower
part of the bone, between the oblique processes
and the body of the vertebra. Each of those
notches meeting with a similar opening in the
vertebra above or below it, forms a foramen for
the passage of blood-vessels, and of the nerves
out of the spine.
The bones of the spine are united together by
means of a substance, which in young subjects
appears to be of a ligamentous, but in adults
more of a cartilaginous nature. This interver-
tebral substance, which forms a kind of partition
between the several vertebræ, is thicker and more
flexible between the lumbar vertebræ than in the
other parts of the spine, the most considerable
motions of the trunk being performed on those
vertebræ. This substance being very elastic,
the extension and flexion of the body, and its
motion backwards and forwards, or to either side,
are performed with great facility. This elasti-
city seems to be the reason why people who have
been long standing, or have carried a considera-
ble weight, are found to be shorter than when
they have been long in bed. In the two first
instances

101
Part I. OSTEOLOGY.
instances the intervertebral cartilages (as they are
usually called) are evidently more exposed to
compression than when we are in bed in an ho-
rizontal posture.
In advanced life these cartilages become shri-
velled, and of course lose much of their elasti-
city. This may serve to account for the decrease
in stature and the stooping forward which are
usually to be observed in old people.
Besides the connection of the several vertebræ
by means of this intervertebral substance, there
are likewise many strong ligaments, both exter-
nal and internal, which unite the bones of the
spine to each other. Their union is also strength-
ed by a variety of strong muscles that cover and
surround the spine.
The bones of the spine are found to diminish
in density, and to be less firm in their texture in
proportion as they increase in bulk; so that the
lowermost vertebræ, though the largest, are not
so heavy in proportion as the upper ones. By
this means the size of these bones is increased
without adding to their weight: a circumstance
of no little importance in a part like the spine,
which, besides flexibility and suppleness, seems
to require lightness as one of its essential proper-
ties.
In very young children, each veterbra con-
sists of three bony pieces united by cartilages
which afterwards ossify.
There are seven vertebra of the neck—they
are 

102 
Part I. OSTEOLOGY.  
are of a firmer texture than the other bones of
the spine. Their transverse processes are forked
for the lodgement of muscles, and at the bottom of
each we observe a foramen, through which pass
the cervical artery and vein. The first and se-
cond of these vertebrae must be described more
particularly. The first approaches almost to an
oval shape—On its superior surface it has two
cavities which admit the condyles of the occipi-
tal bone with which it is articulated. This ver-
tebra, which is called atlas from its supporting
the head, cannot well be described as having
either body or spinous process, being a kind of
bony ring. Anteriorly, where it is articulated
to the odontoid process of the second vertebra,
it is very thin. On its upper surface it has two
cavities which admit the condyles of the occipi-
tal bone. By this connection the head is allow-
ed to move forwards and backwards, but has very
little motion in any other direction.
The second vertebra has gotten the name of
dentata, from its having, at its upper and anterior
part, a process called the odontoid or tooth-like
process, which is articulated with the atlas, to
which this second vertebra may be said to serve as
an axis. This odontoid process is of a cylindri-
cal shape, somewhat flattened, however, ante-
riorly and posteriorly. At its fore-part where
it is received by the atlas, we may observe a
smooth, convex, articulating surface. It is by
means of this articulation that the head performs
its 

103
Part I. OSTEOLOGY.
its rotatory motion, the atlas in that case moving
upon this odontoid process as upon a pivot. But
when this motion is in any considerable degree,
or, in other words, when the head moves much
either to the right or left, all the cervical verte-
bræ seem to assist, otherwise the spinal marrow
would be in danger of being divided transverse-
ly by the first vertebra.
Vertebræ of the back. The spinous process of
each of the cervical vertebræ is shorter, and their
articular processes more oblique, than in the other
bones of the spine.
These 12 vertebræ are of a middle size be-
tween those of the neck and loins. At their
sides we may observe two depressions, one at the
upper and the other at the lower part of the bo-
dy of each vertebra; which uniting with simi-
lar depressions in the vertebræ above and below,
form articulating surfaces, covered with cartilages
for receiving the heads of the ribs; and at the
fore-part of their transverse process (excepting
the two last) we find an articulating surface for
receiving the tuberosity of the ribs.
Lumbar vertebræ. These five vertebræ differ
only from those of the back in their being larger,
and in having their spinous processes at a greater
distance from each other. The most consider-
able motions of the trunk are made on these
vertebræ; and these motions could not be per-
formed with so much ease, were the processes
placed nearer to each other.
The 

104 
Part I. OSTEOLOGY.  
The OS SACRUM which is composed of five
or six pieces in young subjects, becomes one
bone in more advanced age.
It is nearly of a triangular figure, its inferior
portion being bent a little forwards. Its superior
part has two oblique processes which are articu-
lated with the last of the lumbar vertebræ; and
it has likewise commonly three small spinous
processes, which gradually become shorter, so
that the lowermost is not so long as the second,
nor the second as the uppermost. Its transverse
processes are formed into one oblong process,
which becomes gradually smaller as it descends.
Its concave or anterior side is usually smooth, but
its posterior convex side has many prominences
(the most remarkable of which are the spinous
processes just now mentioned), which are filled
up and covered with the muscular and tendinous
parts behind.
This bone has five pair of holes, which af-
ford a passage to blood-vessels, and likewise to
the nerves that are derived from the spinal
marrow, which is continued even here, being
lodged in a triangular cavity, that becomes smaller
as it descends, and at length terminates oblique-
ly at the lower part of this bone. Below the
third division of the os sacrum, this canal is not
completely bony as in the rest of the spine, be-
ing secured as its back part only by a very strong
membrane, so that a wound at this part must be
extremely dangerous.
The 

105
Part I. OSTEOLOGY.
The os sacrum is united laterally to the ossa
innominata or hip-bones, and below to the
coccyx.
Os Coccyx. The coccyx, which, like the os
sacrum, is in young people made up of three
or four distinct parts, usually becomes one bone
in the adult state.
It serves to support the intestinum rectum; and,
by its being capable of some degree of motion
at its articulation with the sacrum, and being
like that bone bent forwards, we are enabled to
fit with ease.
This bone is nearly of a triangular shape, be-
ing broadest at its upper part, and from thence
growing narower to its apex, where it is not
bigger than the little finger.
It has got its name from its supposed resem-
blance a cuckow's beak. It differs greatly from
the vertebræ, being commonly without any pro-
cesses, and having no cavity for the spinal mar-
row, or foramina for the transmission of nerves.
The spine, of which we have now finished
the anatomical description, is destined for many
great and important uses. The medulla spinalis
is lodged in its bony canal secure from external
injury. It serves as a defence to the abdominal
and thoracic viscera, and at the same time sup-
ports the head, and gives a general firmness to
the whole trunk.
We have before compared it to the letter s, and
its different turns will be found to render it not
very 

106 
Part I. OSTEOLOGY. 
very unlike the figure of that letter.—In the neck
we see it projecting somewhat forward to Support
the head, which without this assistance would
require a great number of muscles.—Lower
down, in the thorax, we find it taking a curved
direction backwards, and of course increasing
the cavity of the chest. After this, in the loins,
it again projects forwards in a direction with the
centre of gravity, by which means we are easi-
ly enabled to keep the body in an erect posture,
for otherwise we should be liable to fall forward.
Towards its inferior extremity, however, it
again recedes backward, and thus assists in form-
ing the pelvis, the name given to the cavity in
which the urinary bladder, intestinum rectum,
and other viscera are placed.
If this bony column had been formed only of
one piece, it would have been much more easi-
ly fractured than it is now: and by confining the
trunk to a stiff situation, a variety of motions
would have been altogether prevented, which
are now performed with ease by the great num-
ber of bones of which it is composed.
It is firm, and yet to this firmness there is
added a perfect flexibility. If it be required to
carry a load upon the head, the neck becomes
stiff with the assistance of its muscles, and ac-
commodates itself to the load, as if it was com-
posed only of one bone— n stooping likewise,
or turning to either side, the spine turns in itself
every 

107
Part I. OSTEOLOGY.
every direction, as if all its bones were separated
from each other.
In a part of the body like the spine, that is
made up of so great number of bones, and in-
tended for such a variety of motion, there must
be a greater danger of dislocation than fracture;
but we shall find, that is very wisely guarded
against in every direction by the processes belong-
ing to each vertebra, and by the ligaments, car-
tilages, &c. by which these bones are connect-
ed with each other.
§ 2. Of the Bones of the Thorax.
The thorax, or chest, is composed of many
bones, viz. the sternum which is placed at its an-
terior part, twelve ribs on each side which make
up its lateral parts, and the dorsal vertebræ which
constitute its posterior part. These last have been
already described.
The sternum is the long bone which extends
itself from the upper to the lower part of the
breast anteriorly, and to which the ribs and the
clavicles are articulated.
In children it is composed of several bones
united by cartilages; but as we advance in life,
most of these cartilages ossify, and the sternum
in the adult state is found to consist only of three
pieces, and sometimes become one bone. It is
however generally described as being composed
of three parts—one superior, which is broad,
thick,

108 
Part I. OSTEOLOGY. 
thick, and short; and one in the middle, which
is thinner, narrower, and longer than the other.
It terminates at its lower part by a third piece,
which is called the xyphoid, or sword-like carti-
lage, from its supposed resemblance to the blade
of a sword, and because in young subjects it is
commonly in a cartilaginous state.
We have already observed, that this bone is
articulated with the clavicle on each side. It is
likewise joined to the fourteen true ribs, viz.
seven on its right and seven on its left side.
The ribs are bones shaped like a bow, form-
ing the sides of the chest. There are twelve on
each side. They are distinguished into true and
false ribs: the seven upper ribs which are arti-
culated to the sternum are called true ribs, and
the five lower ones that are not immediately at-
tached to that bone are called false ribs.
On the inferior and interior surface of each rib,
we observe a sinuosity for the lodgement of an
artery, vein, and nerve.
The ribs are not bony through their whole
length, their anterior part being cartilaginous,
They are articulated with the vertebræ and ster-
num. Every rib (or at least the greater num-
ber of them) has at its posterior part two pro-
cesses; one at its extremity called the head of
the rib, by meanss of which it is articulated with
the body of two vertebræ; and another, call-
ed its tuberosity, by which it is articulated with
the transverse process of the lowest of these two
vertebræ. 

109
Part I. OSTEOLOGY.
vertebræ. The first rib is not articulated by its
extremity to two vertebræ, being simply attach-
ed to the upper part of the first vertebra of the
back. The seven superior or true ribs are arti-
culated anteriorly with the sternum by their car-
tilages; but the false ribs are supported in a dif-
ferent manner—the eighth, which is the first of
these ribs, being attached by its cartilages to the
seventh; the ninth to the eighth, &c.
The two lowermost ribs differ likewise from
all the rest in the following particulars: They are
articulated only with the body of the vertebra,
and not with a transverse process; and anterior-
ly, their cartilage is loose, not being attached
to the cartilages of the other ribs; and this seems
to be, because the most considerable motions of
the trunk are not performed on the lumbar verte-
bræ alone, but likewise on the two last vertebræ
of the back; so that if these two ribs had been
confined at the fore part like the other ribs, and
had been likewise articulated with the bodies of
two vertebræ, and with the transverse processes,
the motion of the two last vertebræ, and con-
sequently of the whole trunk, would have been
impeded.
The ribs help to form the cavity of the
thorax; they afford attachment to different
muscles; they are useful in respiration; and
they serve as a security to the heart and lungs.
§ 3. Of

110 
Part I. OSTEOLOGY. 
§ 3. Of the Bones of the Pelvis.
The pelvis is composed of the os sacrum, os
coccygis, and two ossa innominata. The two
first of these bones were included in the account
of the spine, to which they more properly be-
long.
In children, each os innominatum is compos-
ed of three distinct bones; but as we advance in
life the intermediate cartilages gradually ossify,
and the marks of the original separation disap-
pear, so that they become one irregular bone;
still however continuing to retain the names of
ilium, ischium, and pubis, by which their divi-
sions Were originally distinguished, and to be de-
scribed as three different bones by the generality
of anatomists. The os ilium forms the upper
and most considerable part of the bone, the os
ischium its lower and posterior portion, and the
os pubis its fore part.
The os ilium or haunch bone, is articulated
posteriorly to the os sacrum by a firm cartilagin-
ous substance, and is united to the os pubis be-
fore and to the os ischium below. Its superior
portion is thin, and terminates in a ridge called
the crista or spine of the ilium, and more com-
monly known by the name of the haunch. This
crista rises up like an arch; being turned some-
what outwards, so as to resemble the wings of a
phaeton.
Externally this bone is unequally prominent
and 

111
Part I. OSTEOLOGY.
and hollowed for the lodgement of muscles; in-
ternally we find it smooth and concave. At its
lower part there is a considerable ridge en its in-
ner surface. This ridge extends from the os sa-
crum, and corresponds with a similar prominence
both on that bone and the ischium; forms with
the inner part of the ossa pubis what in midwisery
is termed the brim of the pelvis.
The crista, or spine, which at first is an epi-
physis, has two considerable tuberosities; one
anteriorly, and the other posteriorly, which is
the largest of the two: These, from their pro-
jecting more than the parts of the bone below
them, have gotten the name of spinal processes.
From  the anterior spinous process, the sartorius
and tensor vagina femoris muscles have their ori-
gin; and below the posterior process we observe
a considerable niche in the bone, which, in the
recent subject, is formed into a large foramen,
by means of a strong ligament that is stretched
over its lower part from the os sacrum to the
sharp-pointed process of the ischium. This
hole affords a passage to the great sciatic nerve,
and to the posterior crural vessels under the py-
riform muscle, part of which likewise passes out
here.
The os ischium, or hip-bone, which is of a very
irregular figure, constitutes the lower lateral parts
of the pelvis, and is commonly divided into its
body, tuberosity, and ramus. The body forms
the lower and most considerable portion of the
acetabulum, 

112 
Part I. OSTEOLOGY.   
acetabulum, and sends a Sharp-pointed process
backwards, called the spine of the ischium. To
this process the ligament adheres, which was just
now spoken of, as forming a foramen for the
passage of the sciatic nerve.—The tuberosity,
which is the lowest part of the trunk, and sup-
ports us when we sit, is large and irregular, af-
fording origin to several muscles. From this tu-
berosity we find the bone becoming thinner and
narrower. This part, which has the name of
ramus or branch, passes forwards and upwards,
and concurs with the ramus of the os pubis, to
form a large hole called the foramen magnum
ischii, or thyroideum, as it is sometimes named,
from its resemblance to a door or shield. This
hole, which in the recent subject is closed by a
strong membrane called the obturator ligament,
affords through its whole circumference attach-
ment to muscles. At its upper part where we
observe a niche in the bone, it gives passage to
the obturator vessels and nerves, which go to the
inner part of the thigh. Nature seems every
where to avoid an unnecessary weight of bone,
and this foramen, no doubt, serves to lighten the
bones of the pelvis.
The os pubis, or share-bone, which with its
fellow forms the fore-part of the pelvis, is the
smallest division of the os innominatum. It is
united to its fellow by means of a strong car-
tilage, which forms what is called the symphysis
pubis.
3 In
 

113
Part I. OSTEOLOGY.
In each os pubis we may distinguish the body
of the bone, its angle, and ramus. The body
or outer part is united to the os ilium. The angle
comes forward to form the symphysis, and the
ramus is a thin process which unites with the
ramus of the ischium, to form the foramen thy-
roideum.
The three bones we have described as compos-
ing each os innominatum, all assist in forming
the acetabulum, in which the head of the os
femoris is received.
This cavity is every where lined with smooth
cartilage, excepting at its inner part, where we
may observe a little fossa, in which are lodged
the mucilaginous glands of the joint. We may
likewise notice the pit or depression made by the
round ligament, as it is improperly called, which,
by adhering to this cavity and to the head of
the thigh-bone, helps to secure the latter in the
socket.
These bones, which are united to each other
and to the spine by many very strong ligaments,
serve to support the trunk, and to connect it with
the lower extremities; and at the same time to
form the pelvis or bason, in which are lodg-
ed the intestines and urinary bladder, and in
women the uterus; so that the study of this part
of osteology is of the utmost importance in mid-
wifery.
It is worthy of observation, that in women
the os sacrum is usually shorter, broader, and
H more
 

114 
Part I. OSTEOLOGY. 
more hollowed, the ossa ilia more expanded,
and the inferior opening of the pelvis larger than
in men.
Sect. IV. Of the Extremities.
These parts of the Skeleton consist of the up-
per extremity and the lower.
§ 1. Of the UPPER EXTREMITY.
This consists of the Shoulder, the arm, and
the hand.
1. Of the Shoulder.
The shoulder consists of two bones, the cla-
vicula and the scapula.
The former, which is so named from its re-
semblance to the key in use amongst the ancients,
is a little curved at both its extremities like an
italic s. It is likewise called jugulum, or collar-
bone, from its situation. It is about the size of
the little finger, but longer, and being of a very
spongy substance is very liable to be fractured. In
this, as in other long bones, we may distinguish
a body and two extremities. The body is rather
flattened than rounded. The anterior extremity
is formed into a slightly convex head, which is
nearly of a triangular shape. The inferior sur-
face of the head is articulated with the sternum.
The posterior extremity, which is flatter and
broader than the other, is connected to a pro-
cess of the scapula, called acromion. Both 
these

115
Part I. OSTEOLOGY.
these articulations are secured by ligaments, and
in that with the sternum we meet with a move-
able cartilage, to prevent any injury from fric-
tion.
The clavicle serves to regulate the motions of
the scapula, by preventing it from being brought:
too much forwards, or carried too far back-
wards. It affords origin to several muscles, and
helps to cover and protect the subclavian vessels,
which derive their name from their situation un-
der this bone.
The scapula, or shoulder-blade, which is near-
ly of a triangular shape, is fixed to the posterior
part of the true ribs, somewhat in the manner
of a buckler. It is of a very unequal thickness,
and, like all other broad, flat bones, is somewhat
cellular. Exteriorly it is convex, and interiorly
concave, to accommodate itself to the convexity
of: the ribs. We observe in this bone three un-
equal sides, which are thicker and stronger than
the body of the bone, and are therefore termed
its costæ. The largest of the three, called also
the basis, is turned towards the vertebræ. An-
other, which is less than the former, is below
this; and the third, which is the least of the
three, is at the upper part of the bone. Exter-
nally the bone is elevated into a considerable spine,
which rising small at the basis of the scapula, be-
comes gradually higher and broader, and divides
the outer surface of the bone into two fossæ.
H2 The
 

116 
Part I. OSTEOLOGY.  
The superior of these, which is the smallest, serves
to lodge the supra spinatus muscle; and the in-
ferior fossa, which is much larger than the other,
gives origin to the infra spinatus. This spine
terminates in a broad and flat process at the top
of the shoulder, called the processus acromion, to
which the clavicle is articulated. This process is
hollowed at its lower part to allow a passage to
the supra and infra spinati muscles. The scapula
has likewise another considerable process at its
upper part, which, from its resemblance to the
beak of a bird, is called the coracoid process. From
the outer side of this coracoid process, a strong
ligament passes to the processus acromion, which
prevents a luxation of the os humeri upwards.
A third process begins by a narrow neck, and
ends in a cavity called glenoid, for the connection
of the os humeri.
The scapula is articulated with the clavicle and
os humeri, to which last it serves as a fulcrum;
and by varying its position it affords a greater
scope to the bones of the arm in their different
motions. It likewise gives origin to several
muscles, and posteriorly serves as a defence to
the trunk.
2. Bones of the Arm.
The arm is commonly divided into two parts,
which are articulated to each other at the elbow.
The upper part retains the name of arm, proper-
ly

117
Part I. OSTEOLOGY.
ly so called, and the lower part is usually called
the fore arm.
The arm is composed of a single bone called
os humeri. This bone, which is almost of a cy-
lindrical shape, may be divided into its body and
its extremities.
The upper extremity begins by a large, round
smooth head, which is admitted into the glenoid
cavity of the scapula. On the upper and fore
part of the bone there is a groove for lodging the
long head of the biceps muscle of the arm; and
on each side of the groove, at the upper end of the
bone, there is a tubercle to which the spinata
muscles are fixed.
The lower extremity has several processes and
cavities. The principal processes are its two con-
dyles, one exterior and the other interior, and
of these the last is the largest. Between these
two we observe two lateral protuberances, which,
together with a middle cavity, form as it were a
kind of pully upon which the motions of the
fore-arm are chiefly performed. At each side
of the condyles, as well exteriorly as interiorly,
there is another eminence which gives origin to
several muscles of the hand and fingers. Poste-
riorly and superiorly, speaking with respect to
the condyles, we observe a deep fossa which re-
ceives a considerable process of the ulna: and
anteriorly and opposite to this fossa, we observe
another, which is much less and receives another
process of the same bone.
The 

118 
Part I. OSTEOLOGY. 
The body of the bone has at its upper and
and anterior part a furrow which begins from be-
hind the head of the bone, and serves to lodge
the tendon of a muscle. The body of the os
humeri is hollow through its whole length, and,
like all other long bones, has its marrow.
This bone is articulated at its upper part to the
scapula. This articulation, which allows motion
every way, is surrounded by a capsular ligament;
that is sometimes torn in luxation, and becomes
an obstacle to the easy reduction of the bone
Its lower extremity is articulated with the bones
of the fore-arm.
The fore-arm is composed of two bones, the
ulna and radius.  
The ulna or elbow-bone is much less than the
os humeri, and becomes gradually smaller as it
descends to the wrist. At is upper part it has
two processes and two cavities. Of the two pro-
cesses, the largest, which is situated posteriorly
and called the olecranon, is admitted into the pos-
terior fossa of the os humeri. The other process
is placed anteriorly, and is called the coronoid pro-
cess. In bending the arm it enters into the ante-
rior fossa of the os humeri. This process being
much smaller than the other, permits the fore-
arm to bend inwards;  whereas the olecranon,
which is shaped like a hook, reaches the bottom
of its fossa in the os humeri as soon as the arm
becomes straight, and will not permit the fore-arm
to 

119
Part I. OSTEOLOGY.
to be bent backwards. The ligaments likewise
oppose this motion.
Between the two processes we have described,
there is a considerable cavity called the sygmoid
cavity, divided into two fossæ by a small eminence,
which passes from one process to the other; it is
by means of this cavity and the two processes,
that the ulna is articulated with the os humeri by
ginglimus.
At the bottom of the coronoid process inte-
riorly, there is a small sygmoid cavity, which
serves for the articulation of the ulna with the
radius.
The body of the ulna is of a triangular shape:
Its lower extremity terminates by a small head
and a little styloid process. The ulna is articu-
lated above to the os humeri—both above and
below to the radius, and to the wrist at its lower
extremity. All these articulations are secured by
means of ligaments. The chief use of this bone
seems to be to support and regulate the motions
of the radius.
The radius, which is so named from its sup-
posed resemblance to the spoke of a wheel, is
placed at the inside of the fore-arm. It is some-
what larger than the ulna, but not quite so long
as that bone. Its upper part is cylindrical, hol-
lowed superiorly to receive the outer condyle of
the os humeri. Laterally it is admitted into the
little sygmoid cavity of the ulna, and the cylin-
drical part of the bone turns in this cavity in the
motions 

120 
Part I. OSTEOLOGY. 
motions of pronation and supination (I). This
bone follows the ulna in flexion and extension,
and may likewise be moved round its axis in any
direction. The lower extremity of the radius
is much larger and stronger than its upper part;
the ulna, on the contrary, is smaller and weak-
er below than above; so that they serve to sup-
ply each others deficiencies in both those parts.
On the external side of this bone, we observe
a small cavity which is destined to receive the
lower end of the ulna; and its lower extremity
is formed into a large cavity, by means of which
it is articulated with the bones of the wrist, and
on this account it is sometimes called manubrium
manus. It supports the two first bones of the
wrist on the side of the thumb, whereas the ulna
is articulated with that bone of the wrist which
corresponds with the little finger.
Through the whole length both of this bone
and the ulna, a ridge is observed, which af-
fords attachment to an interosseous ligament.
This ligament fills up the Space between the two
bones.
3. Bones of the Hand.
The carpus or wrist consists of eight small
bones
(I) The motions of pronation and supination may be easi-
ly described. If the palm of the hand, for instance, is placed
on the surface of a table, the hand may be said to be in a state
of pronation ; but if the back part of the hand is turned to-
wards the table, the hand will be then in a state of supination.

121
Part I. OSTEOLOGY.
bones of an irregular shape, and disposed in
two unequal rows. Those of the upper row
are articulated with the bones of the fore-arm,
and those of the lower one with the metacarpus.
The ancient anatomists described these bones
numerically; Lyserus seems to have been the
first who gave to each of them a particular name.
The names he adopted are founded on the fi-
gure of the bones, and are now pretty general-
ly received, except the first, which instead of
ΧΟΤνλΟξΙδξς (the name given to it by Lyserus, on
account of its sinus that admits a part of the os
magnum), has by later writers been named Scap-
boides or Naviculare. This, which is the outer-
most of the upper row (considering the thumb as
the outer side of the hand) is articulated with
the radius; on its inner side it is connected with
the os lunare, and below to the trapezium and
trapezoides. Next to this is a smaller bone, called
the os lunare; because its outer side, which is
connected with the scaphoides, is shaped like a
crescent. This is likewise articulated with the
radius. On its inner side it joins the os cunei-
forme, and anteriorly, the os magnum and os
unciforme.
The os cuneiforme, which is the third bone in
the upper row, is compared to a wedge, from
its being broader above, at the back of the
hand, than it is below. Posteriorly it is articu-
lated with the ulna, and anteriorly with the os
unciforme.
These 

122 
Part I. OSTEOLOGY.  
These three bones form an oblong articulating
surface, covered by cartilage, by which the hand
is connected with the fore-arm.
The os pisiforme, or pea-like bone, which is
smaller than the three just now described, though
generally classed with the bones of the upper row,
does not properly belong to either series, being
placed on the under surface of the os cuneiforme,
so as to project into the palm of the hand. The
four bones of the second row correspond with
the bones of the thumb and fingers; the first,
second, and fourth, are from their shapes named
trapezium, trapezoides, and unciforme; the third,
from its being the largest bone of the carpus, is
styled os magnum.
All these bones are convex towards the back,
and slightly concave towards the palm of the
hand; their articulating surfaces are covered with
cartilages, and secured by many strong ligaments,
particularly by two ligamentous expansions, call-
ed the external and internal annular ligaments of
the wrist. The former extends in an oblique
direction from the os pisiforme to the styloid pro-
cess of the radius, and is an inch and an half in
breadth; the latter or internal annular ligament
is stretched from the os pisiforme and os unci-
forme, to the os scaphoides and trapezium. These
annular ligaments likewise serve to bind down
the tendons of the wrist and fingers.
The metacarpus consists of four bones, which
support the fingers; externally they are a little
convex,

123
Part I. OSTEOLOGY.
convex, and internally somewhat concave, where
they form the palm of the hand. They are hol-
low, and of a cylindrical shape.
At each extremity they are a little hollowed
for their articulation; superiorly with the bones
of the carpus, and inferiorly with the first phalanx
of  the fingers, in the same manner as the several
phalanges of the fingers are articulated with each
other.
The five fingers of each hand are composed
of fifteen bones, disposed in three ranks called
phalanges: The bones of the first phalanx, which
are articulated with the metacarpus, are the largest,
and those of the last phalanx the smallest. All
these bones are larger at their extremities than in
their middle part.
We observe at the extremities of the bones
of the carpus, metacarpus, and fingers, seve-
ral inequalities that serve for their articulation
with each other; and these articulations are
strengthened by means of the ligaments which
surround them.
It will be easily understood that this multipli-
city of bones in the hand (for there are 27 in each
hand) is essential to the different motions we wish
to perform. If each finger was composed only
of one bone instead of three, it would be impossi-
ble for us to grasp any thing.
§ 2. Of

124 
Part I. OSTEOLOGY.
§ 2. Of the LOWER EXTREMITIES.
EACH lower extremity is divided into four
parts, viz. the os femoris, or thigh bone: the
rotula, or knee-pan; the leg and the foot.
1. Of the Thigh.
The os femoris. The thigh is composed only
of this bone, which is the largest and strongest
we have. It will be necessary to distinguish its
body and extremities: Its body, which is of a
cylindrical shape, is convex before and con-
cave behind, where it serves to lodge several
muscles.
Throughout two-thirds of its length we observe,
a ridge called linea aspera, which originates from
the trochanters, and after running for some way
downwards, divides into two branches, that ter-
minate in the tuberosities at the lower extremity
of the bone.
At its upper extremity we must describe the
neck and smooth head of the bone, and likewise
two considerable processes: The head, which
forms the greater portion of a sphere unequally
divided, is turned inwards, and received into the
great cotyloid cavity of the os innominatum. At
this part of the bone there is a little fossa to be
observed, to which the round ligament is attach-
ed, and which we have already described as tend-
ing to secure the head of this bone in the great
acetabulum.

125
Part I. OSTEOLOGY.
acetabulum. The neck is almost horizontal, con-
sidered with respect to its situation with the body
of the bone. Of the two processes, the external
one, which is the largest, is called trochanter
major ; and the other, which is placed on the
inside of the bone, trochanter minor. They both
afford attachment to muscles. The articulation
of the os femoris with the trunk is strengthened
by means of a capsular ligament, which adheres
every where round the edge of the great cotyloid
cavity of the os innominatum, and surrounds the
head of the bone.
The os femoris moves upon the trunk in every
direction.
At the lower extremity of the bone are two
processes called the condyles, and an intermedi-
ate smooth cavity, by means of which it is arti-
culated with the leg by ginglimus.
All round the under end of the bone there is
an irregular surface where the capsular ligament
of the joint has its origin, and where blood-vessels
go into the substance of the bone.
Between the condyles there is a cavity poste-
riorly, in which the blood-vessels and nerves
are placed, secure from the compression to which
they would otherwise be exposed in the action
of bending the leg, and which would not fail to
be hurtful.
At the side of each condyle externally, there
is a tuberosity, from whence the lateral ligaments
originate, which are extended down to the tibia.
A 

126 
Part I. OSTEOLOGY.
A ligament likewise arises from each condyle
posteriorly. One of these ligaments passes from
the right to the left, and the other from the
left to the right, so that they intersect each
other, and for that reason are called the cross li-
gaments.
The lateral ligaments prevent the motion of
the leg upon the thigh to the right or left; and
the cross ligaments, which are also attached to
the tibia, prevent the latter from being brought
forwards.
In new-born children all the processes of this
bone are cartilaginous.
2. The Rotula, or Knee-pan.
The rotula, patella, or knee-pan, as it is dif-
ferently called, is a flat bone about four or five
inches in circumference, and is placed at the fore-
part of the joint of the knee. In its shape it is
somewhat like the common figure of the heart,
with its point downward.
It is thinner at its edge than in its middle part;
at its fore-part it is smooth and somewhat con-
vex ; its posterior surface, which is more un-
equal, affords an elevation in the middle which
is admitted between the two condyles of the os
femoris.
This bone is retained in its proper situation by
a strong ligament which every where surrounds
it, and adheres both to the tibia and os femoris;
it 

127
Part I. OSTEOLOGY.
it is likewise firmly connected with the tibia by
means of a strong tendinous ligament of an inch
in breadth, and upwards of two inches in length,
which adheres to the lower part of the patella, and
to the tuberosity at the upper end of the tibia.
On account of this connection, it is very pro-
perly considered as an appendage to the tibia,
which it follows in all its motions, so as to be to
it what the olecranon is to the ulna. There is
this difference, however, that the olecranon is
a fixed process; whereas the patella is moveable,
being capable of sliding from above downwards
and from below upwards. This mobility is es-
sential to the rotatory motion of the leg.
In very young children this bone is entirely
cartilaginous.
The principal use of the patella seems to be
to defend the articulation of the the knee from
external injury; it likewise tends to increase the
power of the extensor muscles to the leg, by re-
moving their direction farther from the centre
of motion in the manner of a pulley.
3. Of the leg.
The leg is composed of two bones: Of these
the inner one, which is the largest, is called ti-
bia; the other is much smaller, and named fi-
bula.
The TIBIA, which is so called from its resem-
blance to the musical pipe of the ancients, has
three 

128 
Part I. OSTEOLOGY. 
three surfaces, and is not very unlike a triangu-
lar prism. Its posterior surface is the broadest;
anteriorly it has a considerable ridge called the
shin, between which and the skin there are no
muscles. At the upper extremity of this bone
are two surfaces, a little concave, and separated
from each other by an intermediate elevation.
The two little cavities receive the condyles of
the os femoris, and the eminence between
them is admitted into the cavity which we spoke
of as being between the two condyles; so that
this articulation affords a specimen of the com-
plete ginglimus. Under the external edge of
the upper end of this bone is a circular flat sur-
face, which receives the head of the fibula.
At the lower and inner portion of the tibia,
we observe a considerable process called mal-
leolus internus. The basis of the bone termi-
nates in a large tranverse cavity, by which it is
articulated with the uppermost bone of the
foot. It has likewise another cavity at its lower
end and outer side, which is somewhat oblong,
and receives the lower end of the fibula.
The tibia is hollow through its whole length.
The FIBULA is a small long bone situated on
the outside of the tibia. Its superior extremity
does not reach quite so high as the upper part of
the tibia, but its lower end descends somewhat
lower. Both above and below, it is articulated
with the tibia by means of the lateral cavities we
noticed in our description of that bone.
3 Its

129
Part I. OSTEOLOGY.
Its lower extremity is stretched out into a co-
ronoid process, which is flattened at its inside,
and is convex externally, forming what is called
the malleolus externus, or outer ancle. This is
rather lower than the malleolus internus of the
tibia.
The body of this bone, which is irregularly
triangular, is a little hollow at its internal sur-
face, which is turned towards the tibia; and it
affords like that bone, through its whole length,
attachment to a ligament, which from its situa-
tion is called the interosseous ligament.
4. Of the foot.
The foot consists of the tarsus, metatarsus, and
toes.
The TARSUS is composed of seven bones,
viz. the astragalus, or os calcis, os naviculare,
os cuboides, and three others called cuneiform
bones.
The ASTRAGALUS is a large bone with which
both the tibia and fibula are articulated. It is
the uppermost bone of the foot; it has several
surfaces to be considered; its upper, and some-
what posterior part, which is smooth and con-
vex, is admitted into the cavity of the tibia. Its
lateral parts are connected with the malleoli of
the two bones of the leg; below, it is articula-
ted with the os calcis, and its anterior surface is
I received 

130 
Part I. OSTEOLOGY.  
received by the os naviculare. All these arti-
culations are secured by means of ligaments.
The os calcis, or calcaneum, which is of
a very irregular figure, it is the largest bone of
the foot. Behind, it is formed into a consider-
able tuberosity called the heel; without this tu-
berosity, which supports us in an erect posture,
and when we walk, we should be liable to fall
backwards.
On the internal surface of this bone, we ob-
serve a considerable sinuosity, which affords a
passage to the tendon of a muscle: and to the pos-
terior part of the os calcis, a strong tendinous
cord called tendo achillis (M) is attached, which
is formed by the tendons of several muscles uni-
ted together. The articulation of this with the
other bones is secured by means of ligaments.
The OS NAVICULARE, or scaphoides, (for
these two terms have the same signification), is
so called on account of its resemblance to a little
bark. At its posterior part, which is concave,
it receives the astragalus; anteriorly it is articu-
lated with the cuneiform bones, and laterally it
is connected with the os cuboides.
The OS CUBOIDES forms an irregular cube.
Posteriorly it is articulated with the os calcis;
anteriorly it supports the two last bones of the
metatarsus, and laterally it joins the third cunei-
form bone and the os naviculare.
Each
(M) This tendon is sometimes ruptured by jumping, danc-
ing, or other violent efforts.

131
Part I. OSTEOLOGY.
Each of the OSSA CUNEIFORMIA, which are
three in number, resembles a wedge, and from
this similitude their name is derived. They are
placed next to the metatarsus by the sides of each
other, and are usually distinguished into os cu-
neiforme externum, medium or minimum, and in-
ternum or maximum. The superior surface of
these bones, from their wedge-like shape, is
broader than that which is below, where they
help to form the sole of the foot; posteriorly
they are united to the os naviculare, and ante-
riorly they support the three first metatarsal
bones.
When these seven bones composing the tarsus
are viewed together in the skeleton, they appear
convex above, where they help to form the up-
per part of the foot; and concave underneath,
where they form the hollow of the foot, in
which the vessels, tendons and nerves of the
foot are placed secure from pressure.
They are united to each other by very strong
ligaments, and their articulation with the foot is
secured by a caspular and two lateral ligaments;
each of the latter is covered by an annular liga-
ment of considerable breadth and thickness, which
serves to bind down the tendons of the foot,
and at the same time to strengthen the articula-
tion.
The os cuneiforme externum is joined laterally
to the os cuboides.
These bones complete our account of the tar-
I2 sus. 


132 
Part I. OSTEOLOGY.  
sus. Though what we have said of this part of
the osteology has been very simple and concise,
yet many readers may not clearly understand it:
but if they will be pleased to view these bones
in their proper situation in the skeleton, all that
we have said of them will be easily understood.
The METATARUS is made up of five bones,
whereas the metacarpus consists only of four.
The cause of this difference is, that in the hand
the last bone of the thumb is not included among
the metacarpal bones; whereas in the foot the
great toe has only two bones. The first of these
bones supports the great toe and is much larger
than the rest, which nearly resemble each other
in size.
These bones are articulated by one extremity
with the cuneiform bones and the os cuboides,
and by their other end with the toes.
Each of the TOES, like the fingers, consists
of three bones, except the great toe, which is
formed of two bones. Those of the other four are
distinguished into three phalanges. Although the
toes are more confined in their motion than the fin-
gers, yet they appear to be perfectly fitted for the
purposes they are designed for. In walking, the toes
bring the centre of gravity perpendicular to the
advanced foot; and as the soles of the foot are
naturally concave, we can at pleasure increase
this cavity, and form a kind of vault, which ad-
justs itself to the different inequalities that occur
to us in walking; and which, without this mode
of 

133
Part I. OSTEOLOGY.
of arrangement, would incommode us exceed-
ingly, especially when bare-footed.
§ 4. Of the Ossa SESAMOIDEA.
BESIDES the bones we have already describ-
ed, there are several small ones that are met with
only in the adult skeleton, and in persons who
are advanced in life; which, from their suppos-
ed general resemblance to the seeds of the sesa-
mum, are called ossa sesamoidea. They are com-
monly to be seen at the first joint of the great
toe, and sometimes at the joints of the thumb;
they are likewise now and then to be found at the
lower extremity of the fibula, upon the con-
dyles of the thigh-bone, under the os cuboides
of the tarsus, and in other parts of the body.
Their size and number seem constantly to be in-
creased by age and hard labour; and as they are
generally found in situations where tendons and
ligaments are most exposed to the action of
muscles, they are now generally considered as
ossified portions of ligaments or tendons.
The upper surface of these bones is usually
convex, and adherent to the tendon that covers
it; the side which is next to the joint is smooth
and flat. Though their formation is accidental,
yet they seem to be of some use, by raising the
tendons farther from the centre of motion, and
consequently increasing the power of the mus-
cles. In the great toe and thumb they are like-
wise 

134 
Part I. OSTEOLOGY.  
wise useful, by forming a groove for the flexor
tendons.
EXPLANATION of the PLATES of OSTEOLOGY.
PLATE XIX.
FIG. 1. A front view of the MALE SKELETON.
A, The os frontis. B, The os parietale. C,
The coronal suture. D, The squamous part of
the temporal bones. E, The squamous suture.
F, The zygoma. G, The mastoid process. H,
The temporal process of the spenoid bone. I,
The orbit. K, The os malæ. L, The os max-
illare superius. M. Its nasal process. N, The
ossa nasi. O, The os unguis, P, The maxilla in-
ferior. Q, The teeth, which are sixteen in
number in each jaw. R, The seven cervical ver-
tebrae, with their intermediate cartilages. S,
Their transverse processes. T, The twelve dor-
sal vertebrae, with their intermediate cartilages,
U, The five lumbar vertebræ. V, Their trans-
verse processes. W, The upper part of the os
sacrum. X, Its lateral parts. The holes seen
on its fore part are the passages of the under-
most spinal nerves and small vessels. Opposite
to the holes, the marks of the original divisions
of the bone are seen. Y, The os ilium. Z, Its
crest or spine. a, The anterior spinous pro-
cesses.

135
Part I. OSTEOLOGY.
esses. b, The brim of the pelvis, c, The is-
hiatic niche. d, The os ischium. e, Its tube-
osity. f, Its spinous process. g, Its crus. h,
The foramen thyroideum. i, The os pubis. k,
The symphysis pubis. l, The crus pubis, m,
The acetabulum, n, The seventh or last true
rib. o, The twelfth or last false rib. p, The up-
per end of the sternum, q, The middle piece.
, The under end, or cartilage ensiformis. s, The
clavicle. t, The internal surface of the scapula.
u, Its acromion, v, Its coracoid process. w, Its
cervix. x, The glenoid cavity, y, The os hu-
meri. z, Its head, which is connected to the
glenoid cavity. 1, Its external tubercle. 2, Its
internal tubercle. 3, The groove for lodging
the long head of the biceps muscle of the arm,
4, The internal condyle. 5, The external con-
dyle. Between 4 and 5, the trochlea. 6. The
radius. 7, Its head. 8, Its tubercle. 9, The ulna.
10, Its coronoid process. 11, 12, 13, 14, 15,
16, 17, 18, The carpus ; composed of os na-
viculare, os lunare, os cuneiforme, os pisiforme,
os trapezium, os trapezoides, os magnum, os
unciforme. 19, The five bones of the metacar-
pus, 20, The two bones of the thumb. 21,
The three bones of each of the fingers. 22, The
os femoris. 23, Its head. 24, Its cervix. 25,
The trochanter major. 26, The trochanter, mi-
nor. 27, The internal condyle. 28, The ex-
ernal condyle. 29, The rotula. 30, The tibia.
31, Its head. 32, Its tubercle. 33, Its spine.
34, The 

136 
Part I. OSTEOLOGY.  
34, The malleolus internus. 35, The fibula.
36, Its head. 37. The malleolus externus. The
tarsus is composed of, 38, The astragalus; 39,
The os calcis; 40, The os naviculare; 41, Three
ossa cuneiformia, and the os cuboides, which is
not seen in this figure. 42, The five bones of
the metatarsus. 43, The two bones of the great
toe. 44, The three bones of each of the small
toes.
FIG. 2. A front view of the SKULL.
A, The os frontis. B, The lateral part of the
os frontis, which gives origin to part of the tem-
poral muscle. C, The superciliary ridge. D,
The superciliary hole through which the frontal
vessels and nerves pass. EE, The orbitar pro-
cesses. F, The middle of the transverse suture.
G, The upper part of the orbit. H, The fora-
men opticum. I, The foramen lacerum. K,
The inferior orbitar fissure. L, The os unguis
M, The ossa nasi. N, The os maxillare superius.
O, Its nasal process. P, The external orbitar
hole through which the superior maxillary ves-
sels and nerves pass. Q, The os malæ. R, A
passage for small vessels into, or out of the orbit.
S, The under part of the left nostril. T, The
septum narium. U. The os spongiosum supe-
rius. V, The os spongiosum infernus. W, The
edge of the alveoli, or spongy sockets, for the
teeth.

137
Part I. OSTEOLOGY.
teeth. X, The maxilla inferior. Y, The pas-
sage for the inferior maxillary vessels and nerves.
FIG. 3. A side-view of the SKULL.
A, The os frontis. B, The coronal suture.
C, The os parietale. D, An arched ridge which
gives origin to the temporal muscle. E, The
squamous suture. F, The squamous part of the
temporal bone; and, farther forwards, the tem-
poral process of the sphenoid bone, G, The zy-
gomatic process of the temporal bone. H, The
zygomatic suture. I, The mastoid process of the
temporal bone. K, The meatus auditorius ex-
ternum L, The orbitar plate of the frontal bone,
under which is seen the transverse suture. M,
The pars plana of the ethmoid bone. N, The
os unguis. O, The right os nasi. P, The su-
perior maxillary bone. Q, Its nasal process.
R, The two dentes incisores. S, The dens ca-
ninus. T, The two molares. U, The three
large molares. V, The os malæ. W, The
lower jaw. X, Its angle. Y, The coronoid
process. Z, The condyloid process, by which
the jaw is articulated with the temporal bone.
FIG. 4. The posterior and right side of the
SKULL.
A, The os frontis. BB, The ossa parietalia.
C, The sagittal suture. D, The parietal hole,
through which a small vein runs to the superior
longitu-

138 
Part I. OSTEOLOGY. 
longitudinal sinus. E. The lambdoid suture.
FF, Ossa triquetra. G, The os occipitis. H,
The squamous part of the temporal bone. I,
The mastoid process. K, The zygoma. L, The
os malæ. M, The temporal part of the sphenoid
bone. N, The superior maxillary bone and
teeth.
FIG. 5. The external surface of the OS FRONTIS,
A, The convex part. B, Part of the tempo-
ral fossa. C, The external angular process. D,
The internal angular process. E, The nasal
process. F, The superciliary hole. H, The
orbitar plate.
FIG. 6. The interior surface of the OS FRONTIS.
AA, The serrated edge which assists to form
the coronal suture. B, The external angular
process. C, The internal angular process. D,
The nasal process. E, The orbitar plate. F, The
cells which correspond with those of the eth-
moid bone. G, The passage from the frontal
sinus. H, The opening which receives the cri-
briform plate of the ethmoid bone. I, The ca-
vity which lodges the fore part of the brain. K,
The spine to which the falx is fixed. L, The
groove which lodges the Superior longitudinal
sinus.
PLATE



 

139
Part I. OSTEOLOGY.
PLATE XX.
FIG. 1. A back view of the SKELETON.
AA, The ossa parietalia. B, The sagittal su-
ture. C, The lambdoid suture. D, The occi-
pital bone. E, The squamous suture. F, The mas-
toid process of the temporal bone. G, The os
malæ. H, The palate plate of the superior max-
illary bones. I, The maxilla inferior. K, The
teeth of both jaws. L, The seven cervical ver-
tebræ. M, Their spinous processes. N, Their
transverse and oblique processes. O, The last of
the twelve dorsal vertebræ. P, The fifth or
last lumbar vertebra. Q, The transverse pro-
cesses. R, The oblique processes. S, The spi-
nous processes. T, The upper part of the os
sacrum. U, The posterior holes which trans-
mit small blood-vessels and nerves. V, The un-
der part of the os sacrum which is covered by a
membrane. W, The os coccygis. X, The os
ilium, Y, Its spine or crest. Z, The ischi-
atic niche. a, The os ischium. b, Its tubero-
sity. c, Its spine. d, The os pubis, e, The fora-
men hydroideum. f, The seventh or last true rib.
g, The twelfth or last false rib. h, The clavicle.
i, The scapula. k, its spine. l, Its acromion.
m, Its cervix, n, Its superior costa. o, Its pofterior
costa. p, Its inferior costa. q, The os humeri.
r, The radius, s, The ulna, t, Its olecranon. u,
All the bones of the carpus, exceting the os
pisiforme,

140 
Part I. OSTEOLOGY.  
pisiforme, which is seen in Plate XIX. fig. 1.
v, The five bones of the metacarpus, w, The
two bones of the thumb, x, The three bones
of each of the fingers, y, The two sesamoid
bones at the root of the left thumb, z, The os
femoris. 1, The trochanter major. 2, The tro-
chanter minor. 3, The linea aspera. 4, The
internal condyle. 5, The external condyle. 6 6,
The semilunar cartilages. 7, The tibia. 8, The
malleolus internus. 9, The fibula. 10, The
malleolus externus. 11, The tarsus. 12, The
metatarsus. 13, The toes.
FIG . 2. The external Surface of the left OS PA-
RIETALE.
A, The convex smooth surface. B, The pa-
rietal hole. C, An arch made by the beginning
of the temporal muscle.
FIG. 3. The internal Surface of the same bone.
A, Its superior edge, which, joined with the
other, forms the sagittal suture. B, The anterior
edge, which assists in the formation of the co-
ronal suture. C. The inferior edge for the squa-
mous suture. D, The posterior edge for the
lambdoid suture. E, A depression made by the
lateral sinus. FF, The prints of the arteries of
the dura mater.
FIG. 4. 

141
Part I. OSTEOLOGY.
FIG. 4. The external Surface of the Left OS TEM-
PORUM.
A, The squamous part. B, The mastoid pro-
cess. C, The zygomatic process. D, The sty-
loid process. E, The petrosal process. F, The
meatus auditorius externus. G, The glenoid
cavity for the articulation of the lower jaw. H,
The foramen stylo-mastoideum for the portio
dura of the seventh pair of nerves. I, Passages
for blood-vessels into the bone. K, The fora-
men mastoideum through which a vein goes to
the lateral sinus.
FIG. 5. The Internal surface of the Left OS TEM-
PORUM.
A, The squamous part; the upper edge of
which assists in forming the squamous suture. B,
The mastoid process. C, The styloid process. D,
The pars petrosa. E, The entry of the seventh
pair, or auditory nerve. F, The fossa, which
lodges a part of the lateral sinus. G, The for-
amen mastoideum.
FIG. 6. The External Surface of the OSSEOUS
CIRCLE, which terminates the meatus audi-
trius externus.
A, The anterior part. B, A small part of the
groove in which the membrana tympani is fixed.
N. B. This, with the subsequent bones of the
ear, are here delineated as large as the life.
FIG. 7. 

142 
Part I. OSTEOLOGY.  
FIG. 7. The Internal Surface of the OSSEOUS
CIRCLE.
A, The anterior part. B, The groove in
which the membrana tympani is fixed.
FIG. 8. The situation and connection of the
small Bones of the EAR.
A, The malleus. B, The incus. C, The
os orbiculare. D, The stapes.
FIG. 9. The MALLEUS, with its Head, Han-
dle, and Small Processes.
FIG. 10. The INCUS, with its Body, Superior
and Inferior branches.
FIG. 11. The OS ORBICULARE.
FIG. 12. The STAPES, with its Head, Base, and
two cura.
FIG. 13. An Internal View of the LBYARINTH
of the EAR.
A, The hollow part of the cochlea, which
forms a share of the meatus auditorius internus.
B, The vestibulum. CCC, The semicircular
canals.
FIG. 14. An External View of the LABYRINTH.
A, The semicircular canals. B, The senestra
ovalis 

143
Part I. OSTEOLOGY.
ovalis which leads into the vestibulum. C, The
senestra rotunda which opens into the cochlea.
D, The different turns of the cochlea.
FIG 15. The Internal Surface of the OS SPHE-
NOIDES.
AA, The temporal processes. BB, The pte-
rygoid processes. CC, The spinous processes.
DD, The anterior clinoid processes. E. The
posterior clinoid process. F, The anterior pro-
cess which joins the ethmoid bone. G, The
sella turcica for lodging the glandula pituitaria.
H, The foramen opticum. K, The foramen
lacerum, L, The foramen rotundum. M, The
foramen ovale. N, The foramen spinale.
FIG. 16. The External Surface of the OS SPHE-
NOIDES.
AA, The temporal processes. BB, The
pterygoid processes. CC, The spinous pro-
cesses. D, The processus azygos. E, The small
triangular processes which grow from the body
of the bone. FF, The orifices of the sphenoid
sinuses. G, The foramen lacerum. H, The
foramen rotundum. I, The foramen ovale. K,
The foramen pterygoideum.
FIG. 17. The External Tiew of the OS ETH-
MOIDES.
A, The nasal lamella. BB, The grooves be-
tween 

144 
Part I. OSTEOLOGY.  
tween the nasal lamella and ossa spongiosa supe-
riora. CC, The ossa spongiosa superiora. DD,
The sphenoidal cornua. See Fig. 16. E.
FIG. 18. The Internal View of the OS ETH-
MOIDES.
A, The crista galli. B, The cribriform plate,
with the different passages of the olfactory nerves.
CC, Some of the ethmoidal cells. D, The right
os planum. EE, The sphenoidal cornua.
FIG. 19. The right SPHENOIDAL CORNU.
FIG. 20. The left SPHENOIDAL CORNU.
FIG. 21.The external Surface of the OS OCCI-
PITIS.
A, The upper part of the bone. B, The su-
perior arched ridge. C, The inferior arched
ridge. Under the arches are prints made by the
muscles of the neck. DD, The two condy-
loid processes which articulate the head with the
spine. E, The cuneiform  process. F, The
foramen magnum through which the spinal mar-
row passes. GG, The posterior condyloid for-
amina which transmit veins into the lateral si-
nuses. HH, The foramina lingualia for the
passage of the nine pair of nerves.
3 FIG. 22. 


 

 

145
Part I. OSTEOLOGY.
FIG. 22. The Internal surface of the OS OCCI-
PITIS.
AA, The two sides which assist to form the
lambdoid suture. B, The point of the cunei-
form process, where it joins the sphenoid bone.
CC, The prints made by the posterior lobes of
the brain. DD, Prints made by the lobes of the
cerebellum. E, The cruciform ridge for the
attachment of the processes of the dura mater.
F, The course of the superior longitudinal si-
nuses. GG, The course of the two lateral si-
nuses. H, The foramen magnum. II, The
posterior condyloid foramina.
PLATE XXI.
FIG. 1. A Side-view of the SKELETON.
AA, The ossa parietalia. B, The sagittal su-
ture. C, The os occipitis, DD, The lambdoid
suture. E, The squamous part of the temporal
bone. F, The mastoid process. G, The mea-
tus auditorius externus. H, The os frontis.
I, The os malæ. K, The os maxillare supe-
rius. L, The maxilla inferior. M, The teeth
of both jaws. N, The seventh, or last cervical
vertebra. O, The spinous processes. P, Their
Transverse and oblique processes. Q, The
twelfth or last dorsal vertebra. R, The fifth or
last lumbar vertebra. S, The spinous processor
K T, Open- 


146 
Part I. OSTEOLOGY. 
T, Openings between the vertebræ for the pas-
sage of the spinal nerves. U, The under end
of the os sacrum. V, The os coccygis. W, The
os ilium. X, The anterior spinous processes.
Y, The posterior spinous processes. Z, The
ischiatic niche, a, The right os ilium. b, The    
ossa pubis. c, The tuberosity of the left os is-
chium. d, The scapula. e, Its spine. f, The
os humeri. g, The radius. h, The ulna. i,
The carpus. k, The metacarpal bone of the
thumb. 1, The metacarpal boneof the fingers.
m, The two bones of the thumb. n, The three
bones of each of the fingers. o, The os femoris.
p, Its head. q, The trochanter major. r, The
external condyle. s, The rotula. t, The tibia.
u, The fibula. v, The malleolus externus. w,   
The astragalus. x, The os calcis. y, The os    
naviculare, z, The three ossa cuneiformia. 1,
The os cuboides. 2, The five metatarsal bones.   
3, The two bones of the great toe. 4, The
three bones of each of the small toes.
FIG. 2. A View of the Internal Surface of the
Base of the SKULL.
AAA, The two tables of the skull with the
diplöe. BB, The orbitar plates of the frontal
bone. C, The crista galli, with cribriform plate
of the ethmoidal bone on each side of it, through
which the first pair of nerves pass. D, The
cuneiform  process of the occipital bone. E.
The cruciform ridge. F, The foramen mag-
num 

147
Part I. OSTEOLOGY.
num for the passage of the spinal marrow. G,
The zygoma, made by the joining of the zygo-
matic processes of the os temporum. I, The
pars mamillaris. K, The pars petrosa. L, The
temporal process of the sphenoid bone. MM,
The anterior clinoid processes. N, The poste-
rior clinoid process. O, The sella turcica. P,
The foramen opticum, for the passage of the op-
tic nerve and occular artery of the left side. Q,
The foramen lacerum, for the third, fourth,
sixth, and first of the fifth pair of the nerves
and ocular vein. R, The foramen rotundum,
for the second of the fifth pair. T, The fora-
men spinale, for the principal artery of the du-
ra mater. U, The entry of the auditory nerve.
V, The passage for the lateral sinus. W, The
passage of the eighth pair of nerves. X, The
passage of the ninth pair.
FIG. 3. A View of the External surface of the
Base of the SKULL.
A, The two dentes incisores of the right side.
B, The dens caninus. C, The two small mo-
lares. D, The three large molares. E, The
foramen incisivum, which gives passage to small
blood-vessels and nerves. F, The palate-plates
oS the ossa maxillaria and palati, joined by the
longitudinal and transverse palate sutures. G,
The foramen palatinum posterius, for the pala-
tine vessels and nerves. H, The os maxillare
K2 superius

148 
Part I. OSTEOLOGY.
superius of the right side. I, The os malæ.
K, The zygomatic process of the temporal bone.
L, The posterior extremity of the ossa spongiosa.
M, The posterior extremity of the vomer, which
forms the back-part of the septum nasi. N, The
pterygoid process of the right side of the sphenoid
bone. OO, The foramina ovalia. P P, The
foramina spinalia. QQ, The passages of the
internal carotid arteries. R, A hole between
the point of each pars petrosa and cuneiform pro-
cess of the occipital bone, which is filled up with
a ligamentous substance in the recent subject. S,
The passage of the left lateral sinus. T, The
posterior condyloid foramen of the left side. U,
The foramen mastoideum. V, The foramen
magnum. W, The inferior orbitar fissure. X,
The glenoid cavity, for the articulation of the
lower jaw. Y, The squamous part of the tem-
poral bone. Z, The mastoid process, at the
inner side of which is a fossa for the posterior bel-
ly of the digastric muscle. a, The styloid pro-
cess. b, The meatus auditorius externus. c,
The left condyle of the occipital bone. d, The
perpendicular occipital spine. ee, The inferior
horizontal ridge of the occipital bone. ff, The
superior horizontal ridge, which is opposite to
the crucial ridge where the longitudinal sinus di-
vides to form the lateral sinuses. ggg, The
lambdoid suture, h, The left squamous suture.
i, The parietal bone.
FIG. 4. 

149
Part I. OSTEOLOGY.
FIG. 4. The anterior surface of the OS NASI.
A, The upper part, which joins the os frontis.
B, The under end, which joins the cartilage of
the nose. C, The inner edge, where they join
each other.
FIG. 5. The posterior surface of the OSSA NASI.
AA, Their cavity, which forms part of the
arch of the nose. BB, Their ridge or spine,
which projects a little to be fixed to the fore-part
of the septum narium.
FIG. 6. The external surface of the OS MAXIL-
LARE SUPERIUS of the left side.
A, The nasal process. B, The orbitar plate.
C, The unequal surface which joins the os malæ.
D, The external orbitar hole. E, The opening
into the nostril. F, The palate-plate. G, The
maxillary tuberosity. H, part of the os palati.
I, The two dentes incisores. K, The dens ca-
ninus. L, The two small dentes molares. M,
The three large dentes molares.
FIG. 7. The internal surface of the OS MAXIL-
LARE SUPERIUS and OS PALATI.
A, The nasal process. BB, Eminences for
the connection of the os spongiosum inferius.
D, The under end of the lachrymal groove. E,
The 

150 
Part I. OSTEOLOGY.  
The antrum maxillare. F, The nasal spine, be-
tween which and B is the cavity of the nostril.
G, The palate-plate. H, The orbitar part of
the os palati. I, The nasal plate. K, The su-
ture which unites the maxillary and palate
bones. L, The pterygoid process of the palate
bones.
FIG. 8. The external surface of the right OS
UNGUIS.
A, The orbitar part. B, The lachrymal part.
C, The ridge between them.
FIG. 9. The internal surface of the right OS
UNGUIS.
This side of the bone has a furrow opposite to
the external ridge ; all behind that is irregular,
where it covers part of the ethmoidal cells.
FIG. 10. The external surface of the left OS
MALÆ.
A, The superior orbitar process. B, The
inferior orbitar process. C, The malar process.
D, The zygomatic process. E, The orbitar
plate. F, A passage for small vessels into or out
of the orbit.
FIG. 11. The internal surface of the left OS
MALÆ.
A, The superior orbitar process. B, The in-
ferior 

151
Part I. OSTEOLOGY.
ferior orbitar process. C, The malar process.
D, The zygomatic process. E, The internal or-
bitar plate or process.
FIG. 12. The external surface of the right OS
SPONGIOSUM INFERIUS.
A, The anterior part. B, The hook-like pro-
cess for covering part of the antrum maxillare.
C, A small process which covers part of the un-
der end of the lachrymal groove. D, The in-
ferior edge turned a little outwards.
FIG. 13. The internal surface of the OS SPON-
GIOSUM INFERIUS.
A, The anterior extremity. B, The upper
edge which joins the superior maxillary and pa-
late bones.
FIG. 14. The posterior and external surface of
the right OS PALATI.
A, The orbitar process. B, The nasal lam-
ella. C, The pterygoid process. D, The pa-
late process.
FIG. 15. The anterior and external surface of
the right OS PALATI.
A, The orbitar process. B, An opening
through which the lateral nasal vessels and nerves
pass. 

152 
Part I. OSTEOLOGY.  
pass. C, The nasal lamella. D, The pterygoid
process. E, The posterior edge of the palate
process for the connection of the velum palati.
F, The inner edge by which the two ossa palati
are connected.
FIG. 16. The right side of the VOMER.
A, The upper edge which joins the nasal lam-
ella of the ethmoid bone and the middle cartilage
of the nose. B, The inferior edge, which is
connected to the superior maxillary and palate
bones. C, The superior and posterior part
which receives the processus azygos of the sphe-
noid bone.
FIG. 17. The MAXILLA INFERIOR.
A, The chin. B, The base and left side. C,
The angle. D, The coronoid process. E, The
condyloid process. F, The beginning of the
inferior maxillary canal of the right side, for
the entry of the nerve and blood-vessels. G,
The termination of the left canal. H, The
two dentes incisores. I, The dens caninus. K,
The two small molares. L, The three large mo-
lares.
FIG. 18. The different classes of the TEETH.
1, 2, A sore and back view of the two ante-
rior dentes incisores of the lower jaw. 3, 4,
Similar 

153
Part I. OSTEOLOGY.
Similar teeth of the upper jaw. 5, 6, A fore
and back view of the dentes canini. 7, 8, The
anterior dentes molares. 9, 10, 11, The poste-
rior dentes molares. 12, 13, 14, 15, 16, Un-
usual appearances in the shape and size of the
teeth.
FIG. 19. The external surface of the OS HY-
OIDES.
A, The body. BB, The cornua. CC, The
appendices.
PLATE XXII.
FIG. 1. A Posterior View of the STERNUM and
CLAVICLES, with the ligament connecting
the clavicles to each other.
a, The posterior surface of the Sternum, bb,
The broken ends of the clavicles. cccc, The
tubercles near the extremity of each clavicle. d,
The ligament connecting the clavicles.
FIG. 2. A Fore-view of the LEFT SCAPULA,
and of a half of the CLAVICLE, with their
Ligaments.
a, The spine of the scapula. b, The acro-
mion, c, The inferior angle, d, Inferior costa.
e, Cervix. f, Glenoid cavity, covered with
cartilage for the arm-bone, gg, The capsular
ligament of the joint. h, Coracoid process. i,
The 

154 
Part I. OSTEOLOGY. 
The broken end of the clavicle. k, Its extremity
joined to the acromion. 1, A ligament coming
out single from the acromion to the coracoid pro-
cess. m, A ligament coming out single from the
acromion, and dividing into two, which are fixed
to the coracoid process.
FIG. 3. The Joint of the Elbow of the LEFT
ARM, with the Ligaments.
a, The os humeri. b, Its internal condyle.
cc, The two prominent parts of its trochlea ap-
pearing through the capsular ligament. d, The
ulna. e, he radius, f, The part of the liga-
ment including the head of the radius.
FIG. 4.  The Bones of the RIGHT-HAND, with
the PALM in view.
a, The radius. b, The ulna. c, The scap-
hoid bone of the carpus. d, The os lunare.
e, The os cuneiforme. f, The os pisiforme. g,
Trapezium. h, Trapezoides. i, Capitatum. k,
Unciforme. 1, The four metacarpal bones of
the fingers. m, The first phalanx. n, The
second phalanx. o, The third phalanx. p,
The metacarpal bone of the thumb. q, The
first joint, r, The second joint.
FIG. 5. The Posterior View of the Bones of the
LEFT-HAND.
The explication of Fig. 4. serves for this fi-
gure;

155
Part I. OSTEOLOGY. 
gure; the same letters pointing out the same
bones, though in a different view.
FIG. 6. The Upper Extremity of the TIBIA,
with the Semilunar Cartilages of the Joint of
the Knee, and some Ligaments.
a, The strong ligament which connects the
rotula to the tubercle of the tibia, bb, The
parts of the extremity of the tibia, covered with
cartilage, which appear within the semilunar
cartilages, cc, The semilunar cartilages, d,
The two parts of what is called the cross liga-
ment.
FIG. 7. The Posterior View of the Joint of the
RIGHT-KNEE.
a, The os femoris cut. b, Its internal con-
dyle, c, Its external condyle, d, The back-
part of the tibia. e, The superior extremity of
the fibula. f, The edge of the internal semilu-
nar cartilage. g, An oblique ligament. h, A
larger perpendicular ligament. i, A ligament
connecting the femur and fibula.
FIG. 8. The Anterior View of the Joint of the
RIGHT-KNEE.
b, The internal condyle. c, Its external con-
dyle. d, The part of the os femoris, on which
the patella moves. e, A perpendicular ligament.
ff, The

156 
OSTEOLOGY. Part I.
ff, The two parts of the crucial ligaments, gg,
The edges of the two moveable semilunar carti-
lages, h, The tibia, i, The strong ligament
of the patella, k, The back part of it where
the fat has been diffected away. 1, The exter-
nal depression. m, The internal one. n, The
cut tibia.
FIG. 9. A View of the inferior part of the Bones
of the RIGHT FOOT.
a, The great knob of the os calcis. b, A pro-
minence on its outside. c, The hollow for the
tendons, nerves, and blood-vessels. d, The an-
terior extremity of the os calcis. e, Part of the
astragalus. f, Its head covered with cartilage.
g, The internal prominence of the os naviculare.
h, The os cuboides. i, The os cuneiforme inter-
num ; k,—Medium ;—l,— Externum. m, The
metatarsal bones of the four lesser toes, n, The
first—o, The second—p, The third phalanx
of the four lesser toes. q, The metatarsal bones
of the great toe. r, Its first—s, Its second joint.
FIG. 10. The Inferior Surface of the two large
SESAMOID BONES, at the first Joint of the
Great Toe.
FIG. 11, The Superior View of the Bones of
the RIGHT FOOT.
a, b, as in Fig. 9. c, The superior head of
the astragalus.—d, & c. as in Fig. 9.
FIG. 12.

157
Part I. OSTEOLOGY.
FIG. 12. The View of the SOLE of the FOOT,
with its Ligaments.
a, The great knob of the os calcis. b, The
hollow for the tendons, nerves, and blood-vessels.
c, The sheaths of the flexores pollicis and digi-
torum longi opened. d, The strong cartilagin-
ous ligament supporting the head of the astraga-
lus. e, h, Two ligaments which unite into one,
and are fixed to the metatarsal bone of the great
toe. f, A ligament from the knob of the os cal-
cis to the metatarsal bone of the little toe. g, A
strong triangular ligament, which supports the
bones of the tarsus. i, The ligaments of the
joints of the five metatarsal bones.
FIG. 13. a, The head of the thigh bone of a
child. b, The ligamentum rotundum connect-
ing it to the acetabulum. c, The capsular liga-
ment of the joint with its arteries injected. d,
The numerous vessels of the mucilaginous gland
injected.
FIG. 14. The Back-view of the Cartilages of the
LARYNX, with the OS HYOIDES.
a, The posterior part of the base of the os
hyoides. bb, Its cornua. c, The appendix of
the right side, d, A ligament sent out from the
appendix of the left side, to the styloid process
of the  temporal bone. e, The union of the
base with the left cornu. ff, The posterior sides
of 

158 
Part II. OF THE INTEGUMENTS. 
of (g) the thyroid  cartilage, hh, Its superior
cornua. ii, Its inferior cornua. k, The cricoid
cartilage. ll, The arytenoid cartilages. m, The
entry into the
epiglottis. o
trachea. p, It
FIG. 15. The Superior Concave surface of the
SESAMOID BONES at the first joint of the
Great Toe, with their Ligaments.
a, Three sesamoid bones, b, The ligament-
ous substance in which they are formed.
PART II.
OF the SOFT PARTS IN GENERAL;
Of the COMMON INTEGUMENTS, with their Appendages;
And of the MUSCLES.
ANATOMICAL writers usually proceed to
a description of the muscles after having
finished the osteology ; but we shall deviate a
little from the common method, with a view to
describe every thing clearly and distinctly, and
to avoid a tautology which would otherwise be
unavoidable. All the parts of the body are so
intimately connected with each other, that it
seems







 

159
Part II. AND MUSCLES.
seems impossible to convey a just idea of any one
of them, without being in some measure oblig-
ed to say something of others; and on this ac-
count we wish to mention in this place the names
and situation of the principal viscera of the body,
that when mention is hereafter made of any one
of them in the course of the work, the reader
may at least know where they are placed.
After this little digression, the common inte-
guments, and after them the muscles will be de-
scribed; we then propose to enter into an exa-
mination of the several viscera and their differ-
ent functions. In describing the brain, occasion
will be taken to speak of the nerves and animal
spirits. The circulation of the blood will follow
the anatomy of the heart, and the secretions and
other matters will be introduced in their proper
places.
The body is divided into three great cavi-
ties. Of these the uppermost is formed by the
bones of the cranium, and incloses the brain and
cerebellum.
The second is composed of the vertebræ of
the back, the sternum, and true ribs, with the ad-
ditional assistance of muscles, membranes, and
common integuments, and is called the thorax—
It contains the heart and lungs.
The third, and inferior cavity, is the abdo-
men. It is separated from the thorax by means
of the diaphragm, and is formed by the lumbar
vertebræ, the os sacrum, the ossa innominata,
and 

160 
Part II. OF THE INTEGUMENTS. 
and the false ribs, to which we may add the pe-
ritonæum, and a variety of muscles. This ca-
vity incloses the stomach, intestines, omentum or
cawl, liver, pancreas, spleen, kidneys, urinary
bladder, and parts of generation.
Under the division of common integuments
are usually included the epidermis, or scarf-skin,
the reticulum mucosum of Malpighi, the cutis or
true skin, and the membrana adiposa.—The hair
and nails, as well as the sebaceous glands may
be considered as appendages to the skin.
SECT. I. Of the SKIN.
§ 1. Of the SCARF-skin.
The epidermis, cuticula, or scarf-skin, is a
fine transparent, and insensible pellicle, destitute
of nerves and blood-vessels, which invests the
body, and everywhere covers the true skin. This
scarf-skin, which seems to be very simple, ap-
pears, when examined with a microscope, to be
composed of several laminæ or scales which are
increased by pressure, as we may observe in the
hands and feet, where it is frequently much
thickened, and becomes perfectly callous. It
seems to adhere to the cutis by a number of very
minute filaments, but may easily be separated
from it by heat, or by maceration in water. Some
anatomical writers have supposed that it is formed
by a moisture exhaled from the whole surface of 
I the


161
Part II. AND MUSCLES.
the body, which  gradually hardens when it
comes into contact with the air. They were per-
haps induced to adopt this opinion, by observing
the speedy regeneration of this part of the body
when it has been by any means destroyed, it ap-
pearing to be renewed on all parts of the surface
at the same time; whereas other parts which have
been injured, are found to direct their growth
from their circumference only towards their cen-
tre. But a demonstrative proof that the epider-
mis is not a fluid hardened by means of the ex-
ternal air, is that the fœtus in utero is found to
have this covering. Lieuwenhoeck supposed its
formation to be owing to the expansion of the
extremities of the excretory vessels which are
found every where upon the surface of the true
skin. Ruysch attributed its origin to the nervous
papillæ of the skin; and Heister thinks it pro-
bable, that it may be owing both to the papillæ
and the excretory vessels. The celebrated Mor-
gagni, on the other hand, contends*, that it is
nothing more than the surface of the cutis, har-
dened and rendered insensible by the liquor am-
nii in utero, and by the pressure of the air. This
is a subject, however, on which we can advance
nothing with certainty.
The cuticle is pierced with an infinite number
of pores or little holes, which afford a passage to
the hairs, sweat, and insensible perspiration, and
L likewise
* Adversar. Anat. II. Animadver. 2.

162 
PART II. OF THE INTEGUMENTS. 
likewise to warm water, mercury, and whatever
else is capable of being taken in by the absorbents
of the skin. The lines which we observe on
the epidermis belong to the true skin. The cu-
ticle adjusts itself to them, but does not form
them.
§ 2. Of the Rete Mucosum.
BETWEEN the epidermis and cutis we meet
with an appearance to which Malpighi, who
first described it, gave the name of rete mucosum,
supposing it to be of a membranous structure,
and pierced with an infinite number of pores;
but the fact is, that it seems to be nothing more
than a mucous substance which may be dissolved
by macerating it in water, while the cuticle and
cutis preserve their texture.
The colour of the body is found to depend on
the colour of this rete mucosum; for in negroes
it is observed to be perfectly black, whilst the
true skin is of the ordinary colour.
The blisters which raise the skin when burnt
or scalded, have been supposed by some to be
owing to a rarefaction of this mucus; but they
are more probably occasioned by an increased
action of the vessels of the part, together with
an afflux and effusion of the thinner parts of the
blood.
§ 3. Of

163
Part II. AND MUSCLES.
§ 3. Of the CUTIS, or True Skin.
The cutis is composed of fibres closely com-
pacted together, as we may observe in leather,
which is the prepared Skin of animals. These
fibres form a thick net-work, which every where
admits the filaments of nerves, and an infinite
number of blood-vessels and lymphatics.
The cutis, when the epidermis is taken off, is
found to have, throughout its whole surface, in-
numerable papillæ, which appear like very mi-
nute granulations, and seem to be calculated to
receive the impressions of the touch, being the
most easily observed where the sense of feeling is
the most delicate, as in the palms of the hands
and on the fingers.
These papillæ are supposed by many anatomi-
cal writers to be continuations of the pulpy sub-
stance of nerves, whose coats have terminated
in the cellular texture of the skin. The great
sensibility of these papillæ evidently proves them
to be exceedingly nervous; but surely the nerv-
ous fibrillæ of the skin are of themselves scarcely
equal to the formation of these papillæ, and it
seems to be more probable that they are formed
like the rest of the cutis.
These papillæ being described, the uses of the
epidermis and the reticulum mucosum will be
more easily understood; the latter serving to
keep them constantly moist, while the former
L2 protects


164 
Part II. OF THE INTEGUMENTS. 
protects them from the external air, and modifies
their too great sensibility.
§ 4. Of the GLANDS of the Skin.
IN different parts of the body we meet, with-
in the substance of the skin, with certain glands
or follicles, which discharge a fat and oily humor
that serves to lubricate and soften the skin. When
the fluid they secrete has acquired a certain de-
gree of thickness, it approaches to the colour
and consistence of suet; and from this appearance
they have derived their name sebaceous glands.
They are found in the greatest number in the
nose, ear, nipple, axilla, groin, scrotum, vagina,
and prepuce.
Besides these sebaceous glands, we read, in
anatomical books, of others that are described
as small spherical bodies placed in all parts of the
skin, in much greater abundance than those just
now mentioned, and named miliary, from their
supposed resemblance to millet-seed. Steno, who
first described these glands, and Malpighi, Ruysch,
Verheyen, Winslow, and others, who have adopt-
ed his opinions on this subject, speak of them as
having excretory ducts, that open on the surface
of the cuticle, and distil the sweat and matter of
insensible perspiration; and yet, notwithstand-
ing the positive manner in which these pretend-
ed glands have been spoken of, we are now suf-
ficiently

165
Part II. AND MUSCLES.
ficiently convinced that their existence is altoge-
ther imaginary.
§ 5. Of the INSENSIBLE Perspiration and
SWEAT.
THE matter of insensible perspiration, or in
other words, the subtile vapour that is continu-
ally exhaling from the surface of the body, is
not secreted by any particular glands, but seems
to be derived wholly from the extremities of the
minute arteries that are every where dispersed
through the skin. These exhaling vessels are
easily demonstrated in the dead subject, by throw-
ing water into the arteries; for then small drops
exude from all parts of the skin, and raise up
the cuticle, the pores of which are closed by
death ; and in the living subject, a looking-glass
placed against the skin, is soon obscured by the
vapour. Bidloo fancied he had discovered ducts
leading from the cutis to the cuticle, and trans-
mitting this fluid; but in this he was mistaken.
When the perspiration is by any means in-
creased, and several drops that were insensible
when separate, are united together and condens-
ed by the external air, they form upon the skin
small, but visible, drops called sweat (N). This
particularly happens after much exercise, or
whatever occasions an increased determination of
fluids
(N) Lieuwenhoeck asserts that one drop of sweat is formed
by the conflux of fifteen drops of perspirable vapour. 

166 
Part II. OF THE INTEGUMENTS. 
fluids to the surface of the body; a greater quan-
tity of perspirable matter being in such cases
carried through the passages that are destined to
convey it off.
It has been disputed, indeed, whether the in-
sensible perspiration and sweat are to be consider-
ed as one and the same excretion, differing only
in degree ; or whether they are two distinct ex-
cretions derived from different sources. In sup-
port of the latter opinion, it has been alledged,
that the insensible perspiration is agreeable to na-
ture, and essential to health, whereas sweat may
be considered as a species of disease. But this
argument proves nothing; and it seems probable,
that both the insensible vapour and the sweat are
exhaled in a similar manner, though they differ
in quantity, and probably in their qualities; the
former being more limpid, and seemingly less
impregnated with salts than the latter: at any
rate we may consider the skin as an emunctory
through which the redundant water, and some-
times the other more saline parts of the blood,
are carried off. But the insensible perspiration
is not confined to the skin only—a great part of
what we are constantly throwing off in this way
is from the lungs. The quantity of fluid exhal-
ed from the human body by this insensible per
spiration is very considerable. Sanctorius (O)
an
(O) The insensible perspiration is sometimes distinguished
by the name of this physician, who was born in the territo-
ries 

167
Part II. AND MUSCLES.
an Italian physician, who indefatigably passed a
great many years in a series of statical experiments,
demonstrated long ago what has been confirmed
by later observations, that the quantity of vapour
exhaled from the skin and from the surface of
the lungs, amounts nearly to 5-8ths of the ali-
ment we take in. So that if in the warm climate
of Italy a person eats and drinks the quantity of
eight pounds in the course of a day, five pounds
of it will pass off by insensible perspiration, while
three pounds only will be evacuated by stool, u-
rine, saliva, &c. But in countries where the
degree of cold is greater than in Italy, the quan-
tity of perspired matter is less; in some of the
more northern climates, it being found not to
equal the discharge by urine. It is likewise ob-
served to vary according to the season of the year,
and according to the constitution, age, sex, dis-
eases, diet, exercise, passions, &c. of different
people.
From
ries of Venice, and was afterwards a professor in the uni-
versity of Padua. After estimating the aliment he took in,
and the sensible secretions and discharges, he was enabled to
ascertain with great accuracy the weight or quantity of in-
sensible perspiration by means of a statical chair which he
contrived for this purpose; and from his experiments, which
were conducted with great industry and patience, he was
led to determine what kinds of solid or liquid aliment in-
creased or diminished it. From these experiments he form-
ed a system, which he published at Venice in 1614, in the
form of aphorisms, under the title of "Ars de Medicina
Statica." 

168 
Part II. OF THE INTEGUMLNTS. 
From what has been said on this subject, it
will be easily conceived, that this evacuation can-
not be either much increased or diminished in
quantity without affecting the health.
The perspirable matter and the sweat are in
some measure analogous to the urine, as appears
from their taste and saline nature (P). And it is
worthy of observation, that when either of these
secretions is increased in quantity, the other is di-
minished ; so that they who perspire the least,
usually pass the greatest quantity of urine, and
vice versa.
§ 6. Of the NAILS.
The nails are of a compact texture, hard
and transparent like horn. Their origin is still
a subject of dispute. Malpighi supposed them
to be formed by a continuation of the papillæ
of the skin : Ludwig, on the other hand, main-
tained, that they were composed of the extre-
mities of blood-vessels and nerves; both these
opinions are now deservedly rejected.
They seem to possess many properties in com-
mon with the cuticle; like it they are neither
vascular nor sensible, and when the cuticle is se-
parated from the true skin by maceration or
other means, the nails come away with it.
They
(P) Minute chrystals have been observed to shoot upon the
cloaths of men who work in glass-houses. Haller Elem.
Phys.

169
Part II. AND MUSCLES.
They appear to be composed of different lay-
ers, of unequal size, applied one over the other.
Each layer seems to be formed of longitudinal
fibres.
In each nail we may distinguish three parts,
viz. the root, the body or middle, and the extre-
mity. The root is a soft, thin, and white sub-
stance terminating in the form of a crescent; the
epidermis adheres very strongly to this part;
the body of the nail is broader, redder and
thicker, and the extremity is of still greater firm-
ness.
The nails increase from their roots, and not
from their upper extremity.
Their principal use is to cover and defend the
ends of the fingers and toes from external in-
jury.
§ 7. Of the HAIR.
The hairs, which from their being general-
ly known do not seem to require any definition,
arise from distinct capsules or bulbs seated in the
cellular membrane under the skin (Q). Some
of
(Q) Malpighi, and after him the celebrated Ruysch, sup-
posed the hairs to be continuations of nerves, being of opi-
nion that they originated from the papillæ of the skin, which
they considered as nervous; and as a corroborating proof
of what they advanced, they argued the pain we feel in
plucking them out; but later anatomists seem to have re-
jected this doctrine, and consider the hairs as particular bo-
dies, not arising from the papillæ (for in the parts where
the papillæ; abound most there are no hairs), but from bulbs
or capsule, which are peculiar to them. 

170 
Part II. OF THE INTEGUMENTS.
of these bulbs inclose several hairs. They may
be observed at the roots of the hairs which form
the beard or whiskers of a cat.
The hairs, like the nails, grow only from be-
low by a regular propulsion from the root, where
they receive nourishment. Their bulbs, when
viewed with a microscope, are found to be of
various shapes. In the head and scrotum they
are roundish; in the eye-brows they are oval;
in the other parts of the body they are nearly
of a cylindrical shape. Each bulb seems to con-
sist of two membranes, between which there is
a certain quantity of moisture. Within the bulb
the hair separates into three or four fibrillæ; the
bodies of the hairs, which are the parts without
the skin, vary in softness and colour according
to the difference of climate, age, or tempera-
ment of the body (R).
Their general use in the body does not seem
to be absolutely determined ; but hairs in parti-
cular parts, as on the eye-brows and eye-lids,
are destined for particular uses, which will be
mentioned when those parts are described.
§ 8. Of
(R) The hairs differ likewise from each other, and may not
be improperly divided into two classes; one of which may in-
clude the hair of the head, chin, pubes, and axillæ; and
the other, the softer hairs, which are to be observed almost
every where on the surface of the body.

171
PART II. AND MUSCLES.
§ 8. Of the CELLULAR MEMBRANE and FAT.
THE CELLULAR MEMBRANE is found to in-
vest the most minute fibres we are able to trace;
so that by modern physiologists, it is very pro-
perly considered as the universal connecting me-
dium of every part of the body.
It is composed of an infinite number of mi-
nute cells united together, and communicating
with each other. The two diseases peculiar to
this membrane are proofs of such a communica-
tion; for in the emphysema all its cells are filled
with air, and in the anasarca they are univer-
sally distended with water. Besides these proofs
of communication from disease, a familiar in-
stance of it may be observed amongst butchers,
who usually puncture this membrane, and by
inflating it with air add to the good appearance
of their meat.
The cells of this membrane serve as refer-
voirs to the oily part of the blood or Fat, which
seems to be deposited in them, either by transu-
dation through the coats of the arteries, that ra-
mify through these cells, or by particular ves-
sels, continued from the end of arteries. These
cells are not of a glandular structure, as Malpi-
ghi and others after him have supposed. The
fat is absorbed and carried back into the system
by the lymphatics. The great waste of it in
many diseases, particularly in the consumption,
is a sufficient proof that such an absorption takes
place. 
The

172 
PART II. OF THE INTEGUMENTS.
The fullness and size of the body are in a
great measure proportioned to the quantity of
fat contained in the cells of this membrane.
In the living body it seems to be a fluid oil,
which concretes after death. In graminivorous
animals, it is found to be of a firmer consistence
than in man.
The fat is confined to the skin alone, being
met with every where in the interstices of mus-
cles, in the omentum, about the kidneys, at the
basis of the heart, in the orbits, &c.
The chief uses of the fat seem to be to afford
moisture to all the parts with which it is con-
nected; to facilitate the action of the muscles;
and to add to the beauty of the body, by making
it every where smooth and equal.
SECT. II. Of the MUSCLES.
THE MUSCLES are the organs of motion. The
parts that are usually included under this name
consist of distinct portions of flesh, susceptible
of contraction and relaxation; the motions of
which, in a natural and healthy state, are sub-
ject to the will, and for this reason they are call-
ed voluntary muscles. But besides these, there
are other parts of the body that owe their power
of contraction to their muscular fibres; thus
the heart is of a muscular texture, forming what
is called a hollow muscle; and the urinary blad-
der, stomach, intestines, &c. are enabled to
act upon their contents, merely because they are
provided

173
PART II. AND MUSCLES.
provided with muscular fibres. These are called
involuntary muscles, because their motions are
not dependent on the will. The muscles of res-
piration, being in some measure influenced by
the will, are said to have a mixed motion.
The names by which the voluntary muscles
are distinguished, are founded on their size, fi-
gure, situation, use, or the arrangement of their
fibres, or their origin and insertion. But be-
sides these particular distinctions, there are cer-
tain general ones that require to be noticed.
Thus, if the fibres of a muscle are placed pa-
rallel to each other in a straight direction, they
form what is styled a rectilinear muscle; if the
fibres cross and intersect each other, they consti-
tute a compound muscle; a radiated one, if the
fibres are disposed in the manner of rays; or a
penniform muscle, if, like the plume of a pen,
they are placed obliquely with respect to the
tendon.
Muscles that act in opposition to each other,
are called antagonistæ; thus every extensor or
muscle has a flexor for its antagonist, and vice
versa. Muscles that concur in the same action
are styled congeneres.
The muscles being attached to the bones, the
latter may be considered as levers that are mov-
ed in different directions by the contraction of
those organs.
The end of a muscle which adheres to the
most fixed part is usually called the origin, and
that

174 
PART II. OF THE INTEGUMENTS.
that which adheres to the more moveable part
the insertion, of the muscle.
In every muscle we may distinguish two kinds
of fibres; the one soft, of a red colour, sensi-
ble, and irritable, called fleshy fibres; the other
of a firmer texture, of a white glistening colour,
insensible without irritability or the power of
contracting, and named tendinous fibres. They
are occasionally intermixed; but the fleshy fi-
bres generally prevail in the belly or middle part
of the muscle, and the tendinous ones in the ex-
tremities. If these tendinous fibres are formed
into a round slender chord, they form what is
called the tendon of the muscle; on the other
hand, if they are spread into a broad flat sur-
face, the extremity of the muscle is styled apo-
neurosis.
The tendons of many muscles, especially when
they are long and exposed to pressure or friction
in the grooves formed for them in the bones, are
surrounded by a tendinous sheath or fascia, in
which we sometimes find a small mucous sac or
bursa mucosa, which obviates any inconvenience
from friction. Sometimes we find whole mus-
cles, and even several muscles, covered by a fas-
cia of the same kind, that affords origin to ma-
ny of their fibres, dipping down between them,
adhering to the ridges of the bones, and thus
preventing them from swelling too much when
in action. The most remarkable instance of
such a covering is the fascia lata of the the thigh.
Each 

175
PART II. AND MUSCLES.
Each muscle is inclosed by a thin covering of
cellular membrane, which has been sometimes
improperly considered as peculiar to the muscles,
and described under the name of propria mem-
brana musculofsa. This cellular covering dips
down into the substance of the muscle, connect-
ing and surrounding the most minute fibres we
are able to demonstrate, and affording a support
to their vessels and nerves.
Lieuwhenhock fancied he had discovered, by
means of his microscope, the ultimate division
of a muscle, and that he could point out the sim-
ple fibre, which appeared to him to be an hun-
dred times less than a hair; but he was after-
wards convinced how much he was mistaken on
this subject, and candidly acknowledged, that
what he had taken for a simple fibre was in fact
a bundle of fibres.
It is easy to observe several of these fasculi or
bundles in a piece of beef, in which, from the
coarseness of its texture, they are very evident.
The red colour which so particularly distin-
guishes the muscular or fleshy parts of animals,
is owing to an infinite number of blood-vessels
that are dispersed through their substance. When
we macerate the fibres of a muscle in wa-
ter, it becomes of a white colour like all other
parts of the body divested their blood. The
blood-vessels are accompanied by nerves, and
they are both distributed in such abundance to
these parts, that in endeavouring to trace the
course 

176 
PART II. OF THE INTEGUMENTS.
course of the blood-vessels in a muscle, it would
appear to be formed altogether by their ramifica-
tions ; and in an attempt to follow the branches
of its nerves, they would be found to be equal
in proportion.
If a muscle is pricked or irritated, it imme-
diately contracts. This is called its irritable
principle; and this irritability is to be consider-
ed as the characteristic of muscular fibres, and
may serve to prove their existence in parts that
are too minute to be examined by the eye. This
power, which disposes the muscles to contract
when stimulated, independent of the will, is
supposed to be inherent in them; and is there-
fore named vis insita. This property is not to
be confounded with elasticity, which the mem-
branes and other parts of the body possess in a
greater or less degree in common with the mus-
cles; nor with sensibility, for the heart though
the most irritable, seems to be the least sensible
of any of the muscular parts of the body.
After a muscular fibre has contracted, it soon
returns to a state of relaxation, till it is excited
afresh, and then it contracts and relaxes again.
We may likewise produce such a contraction,
by irritating the nerve leading to a muscle, al-
though the nerve itself is not affected.
This principle is found to be greater in small
than in large, and in young than in old, ani-
mals.
In the voluntary muscles these effects of con-
I traction 


177
PART II. AND MUSCLES.
traction and relaxation of the fleshy fibres are
produced in obedience to the will, by what may
be called the vis nervosa, a property that is not
to be confounded with the vis insita. As the
existence of a vis insita different from a vis ner-
vea, was the doctrine taught by Doctor Haller
in his Elem. Phys. but is at present called in ques-
tion by several, particularly Doctor Monro, we
think it necessary to give a few objections, as sta-
ted in his Observations on the Nervous System:
Vis Nervea. "The chief experiment (says
the Doctor) which seems to have led Dr. Hal-
ler to this opinion, is the well known one, that
the heart and other muscles, after being detach-
ed from the brain, continue to act spontaneously,
or by stimuli may be roused into action for a
considerable length of time; and when it cannot
be alledged, says Dr. Haller, that the nervous
fluid is by the mind, or otherwise, impelled into
the muscle.
"That in this instance we cannot compre-
hend by what power the nervous fluid or energy
can be put in motion, must perhaps be granted:
But has Dr. Haller given a better explanation of
the manner in which his supposed vis insita be-
comes active?
"If it be as difficult to point out the cause of
the action of the vis insita as that of the action
of the vis nervea, the admission of that new
power, instead of relieving, would add to our
perplexity.
M "We


178 
PART II. OF THE INTEGUMENTS.
"We Should then have admitted, that two
causes of a different nature were capable of pro-
ducing exactly the same effect; which is not in
general agreeable to the laws of nature.
"We should find other consequences arise
from such an hypothesis, which tend to weaken
the credibility of it. For instance, if in a sound
animal the vis nervea alone produces the contrac-
tion of the muscles, we will ask what purpose
the vis insita serves? If both operate, are we to
suppose that the vis nervea, impelled by the
mind or living principle, gives the order, which
the vis insita executes, and that the nerves are
the internuntii; and so admit two wise agents
employed in every the most simple action? But
instead of speculating farther, let us learn the ef-
fect of experiments, and endeavour from these
to draw plain conclusions.
"1. When I poured a solution of opium in
water under the skin of the leg of a frog, the mus-
cles, to the surface of which it was applied, were
very soon deprived of the power of contraction.
In like manner, when I poured this solution in-
to the cavity of the heart, by opening the
vena cava, the heart was almost instantly de-
prived of its power of motion, whether the ex-
periment was performed on it fixed in its place,
or cut out of the body.
"2. I opened the thorax of a living frog; and
then tied or cut its aorta, so as to put a stop to
the circulation of its blood.
"I then 

179
Part II. AND MUSCLES.
"I then opened the vena cava, and poured
the solution of opium into the heart; and found
not only that this organ was instantly deprived
of its powers of action, but that in a few mi-
nutes the most distant muscles of the limbs were
extremely weakened. Yet this weakness was
not owing to want of circulation, for the frog
could jump about for more than an hour after
the heart was cut out.
"In the first of these two experiments, we
observed the supposed vis insita destroyed by the
opium; in the latter, the vis nervea; for it is
evident that the limbs were affected by the sym-
pathy of the brain, and of the nervous system
in general, with the nerves of the heart.
"3. When the nerve of any muscle is first
divided by a transverse section, and then burnt
with a hot iron, or punctured with a needle,
the muscle in which it terminates contracts vio-
lently, exactly in the same manner as when the
irritation is applied to the fibres of the muscle.
But when the hot iron, or needle, is confined
to the nerve, Dr. Haller himself must have ad-
mitted, that this vis nervea, and not the vis in-
sita, was excited. But here I would ask two
questions.
"First, Whether we do not as well under-
stand how the vis nervea is excited when irrita-
tion is applied to the muscle as when it is appli-
ed to the trunk of the nerve, the impelling
M2 power 


180 
Part II. OF THE INTEGUMENTS.
power of the mind seeming to be equally want-
ing in both cases?
"Secondly, If it appears that irritation ap-
plied to the trunk of a nerve excites the vis ner-
vea, why should we doubt that it can equally
well excite it when applied to the small and ve-
ry sensible branches and terminations of the nerve
in the muscle?
"As, therefore, it appears that the supposed
vis insita is destroyed or excited by the same
means as the vis nervea; nay, that when, by
the application of the opium to the heart of a frog,
after the aorta is cut and the circulation in-
terrupted, we have destroyed the vis insita, the
vis nervea is so much extinguished, that the
animal cannot act with the distant muscles of the
limb; and that these afterward grow very tor-
pid, or lose much of their supposed vis insita;
it seems clearly to follow, that there is no just
ground for supposing that any other principle
produces the contraction of a muscle."
The vis nervosa, or operation of the mind, if
we may so call it, by which a muscle is brought
into contraction, is not inherent in the muscle
like the vis insita; neither is it perpetual, like
this latter property. After long continued or
violent exercise, for example, the voluntary
muscles become painful, and at length incapa-
ble of further action; whereas the heart and
other involuntary muscles, the motions of which
depend solely on the vis insita, continue through
life 

181
Part II. AND MUSCLES.
life in a constant state of action, without any
inconvenience or waste of this inherent principle;
The action of the vis nervosa on the volun-
tary muscles, constitutes what is called muscular
motion; a subject that has given rise to a variety
of hypotheses, many of them ingenious, but
none of them satisfactory.
Borelli and some others have undertaken to
explain the cause of contraction, by supposing
that every muscular fibre forms as it were a chain
of very minute bladders, while the nerves which
are distributed through the muscle, bring with
them a supply to animal spirits, which at our
will fill these bladders, and by increasing their
diameter in width, shorten them, and of course
the whole fibre.
Borelli supposes these bladders to be of a
rhomboidal shape; Bernouilli on the other hand
contends that they are oval. Our countryman,
Cowper, fancied he had filled them with mer-
cury; the cause of this mistake was probably
owing to the mercury's insinuating itself into
some of the lymphatic vessels. The late inge-
nius Mr. Elliot undertook to account for the phe-
nomena of muscular motion on principles very
different from those just now mentioned. He
supposed that a deplogisticated state of the blood
is requisite for muscular action, and that a com-
munication of phlogiston to the blood is a neces-
sary effect of such action.
We know that the muscular fibre is shorten-
ed,

183 
Part II. OF THE INTEGUMENTS, &c. 
ed, and that the muscle itself swells when in
action: but how these phenomena are produced,
we are unable to determine. We likewise know
that the nerves are essential to muscular motion;
for upon dividing or making a ligature round
the nerve leading to a muscle, the latter becomes
incapable of motion. A ligature made on the
artery of a muscle produces a similar effect; a
proof this, that a regular supply of blood is also
equally necessary to muscular motion. The
cause of palsy is usually not to be fought for in
the muscle affected, but in the nerve leading to
that muscle, or in that part of the brain or spi-
nal marrow from which the nerve derives its
origin.
Of the particular Muscles.
As the enumeration and description of the
the particular muscles must be dry and uninter-
taining to the generality of readers, yet cannot
be altogether omitted in a work of this nature, it
appeared eligible to throw this part of the sub-
ject into the form of a table; in which the
name, origin, insertion, and principal use of
each muscle, will be found described in few words,
and occasionally its etymology when it is of
Greek derivation or difficult to be understood.
A TABLE

183
PART II. A TABLE of the MUSCLES.
A TABLE of the MUSCLES arranged according to their SITUATION.
[N. B. This table does not include all the muscles of the body; those belonging to the eyes, internal ear, intestinom rectum,
and the male and female organs of generation, being described in other parts of the work. The reader will be pleased to
observe likewise, that although all the muscles (a few only excepted) we in pairs, mention is here made of the muscles
of one side.]
Muscles situated Name. Origin. Insertion Use.
under the integu-
ments of the cra-
nium- 
1. Occipito frontalis. 
From the transvere 
ridge of the os oc-
cipitis.
Into the skin of the 
eye-brows.
To pull the skin of 
the head back-
wards, and to raise
the eye-brows and 
skin of the fore-
head.
2. Corrugator super-
cilii.
From above the join-
ing of the os fron-
tis, os nasi, and os
maxillare.
Into the inner part 
of the occipito- 
frontalis. 
To draw the eye-
brows towards each
other, and to wrinkle
the forehead.
-of the
eye-lids-
1. Orbicularis palpe- 
brarum.
From around the edge 
of the orbit.
Into the nasal pro-
cess of the os 
maxillare. 
To shut the eye.
2. Levator palpebræ 
superioris.
From the bottom of 
the orbit, near the 
optic foramen.
Into the cartilage of 
the upper eye-lid.
To open the eye.


184 
Part II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
—of external ear 
1. Attolens auri-
culam.
From the tendon of 
the occipito fron- 
talis near the os
temporis.
Into the upper part	
of the ear.
To raise the ear.			 
2. Anterior auriculæ.
From near the back 
part of the zygoma.
Into an eminance be-
hind the helix.
To raise this emi-
nence, and to pull
it forwards.
3. Retrahentes (s) au-
riculæ.
From the outer and 
back part of the 
root of the mastoid
process.
Into the convex part
of the concha.
To stretch the con- 
cha, and pull the 
ear backwards.
MUSCLES of the car- 
tilages of the ear 
1. Tragicus. 
From the outer and 
middle part of the 
concha, near the
tragus.
Into the upper part
of the tragus.
To depress the con-
cha, and pull the
point of the tragus
a little outwards.
2. Anti-tragicus. 
From the root of the 
inner part of the 
helix.
Into the upper part
of the anti-tragus.
To dilate the mouth
of the concha.
3. Transversus-auri- 
culæ
From the upper part 
of the concha.
Into the inner part
of the helix.
To stretch the conc
and scapha, and
likewise to pull the 
(s) These are three small slender muscles. The inferior one is sometimes wanting.

185
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
parts it is connect-
ed with towards 
each other.
4. Helicis major.
From the upper, ante-
rior, and acute part 
of the helix.
Into the cartilage of
the helix, a little
above the tragus.
To depress the upper
part of the helix.
5. Helicis minor.
From the lower and 
fore part of the he- 
lix.
Into the helix, near
the fissure in its
cartilage.
To contract the fis-
sure.
—of the nose, 
1. Compressor (T)
naris.
From the outer part 
of the root of the 
ala nasi. 
Into the nasal pro-
cess of the os max-
illare, and anterior
extremity of the os
nasi.
To straighten the nos-
trils, and likewise
to corrugate the
skin of the nose.
—of the mouth and lips,
1. Levator labii supe- 
rioris, alæque nasi. 
From the outer part										 
of the orbitar pro- 
cess of the os max-
illare, and from the
nasal process of
that bone, where
it joins the os fron-
tis.
Into the upper lip and
ala of the nose.
To draw the upper lip
and skin of the nose
upwards and out- 
wards.										 
(T) The nose is affected by fibres of the occipito frontalis, and by several muscles of the face; but this pair, the com-
pressores, is the only one that is proper to it.

186 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
2. Levator anguli oris. 
From the os maxil- 
lare superlus, be- 
tween the orbitar 
foramen and the
first dens molares.
Into the orbicularis
oris at the angle of	
the mouth.
To draw the corner
of the mouth. 
3. Zygomaticus ma- 
jor. 
From the os malæ
near the zygoma- 
tic suture.
Into the angle of the
mouth.
To raise the angle of 
the mouth, and 
make the cheek 
prominent, as in
laughing.
4. Zygomaticus mi- 
nor. 
Immediately above
the origin of the 
zyg. major.
Into the angle of the 
mouth.
To raise the angle of
the month oblique-
ly outwards.
5. Buccinator.
From the alveoli of 
the dentes molares 
in the upper and
lower jaws.
Into the angle of the
mouth.
To contract the mouth
and draw the angle
of it outwards and 
backwards.
6. Depressor labii su-
perioris, alæque
nasi.
From the os maxill.
super. immediately 
above the gums of 
the dentesincisores.
Into the root of the
ala nasi and upper
lip.
To draw the ala nasi
and upper lip down-
wards.
7. Depressor auguli
oris.
At the side of the 
chin from the low-
er edge of the max-
illa inferior.
Into the angle of the 
mouth.
To draw the corner 
of the mouth down-
wards.

187
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
8. Depressor labii in- 
ferioris.
From the lower and
anterior part of
the maxilla infe-
rior.
Into the under lip.
To draw the under
lip downwards and
somewhat out-
wards.
9. Levator labii infe- 
noris.
From near the gums
of the incisores and
caninnus of the max-
illa inferior.
Into the under lip and
skin of the chin.
To raise the under 
lip and skin of the 
chin.
10. Orbicularis O-
ris (U).
To shut the mouth by
constringing the lips.
Muscles of the low-
er jaw, 
1. Temporalis.
From part of the os 
bregmatis and os 
frontis; squamous 
part of the os tem-
poris; back part of
the os malæ, and
the temporal pro-
cess of the os sphe-
noides (V)
Into the coronoid pro- 
cess of the lower
jaw.
To move the lower
jaw upwards.
(U) This muscle is, in a great measure, if not wholly, formed by the buccinator, zygomatici, depressores, and other
muscles that move the lips. Its fibres surround the mouth like a ring. 
(V) Some of its fibres likewise have their origin from a strong fascia that covers the muscle and adheres to the bone round the whole circumference of its origin. When we remove this covering, we find the muscle of a semicircular shape with its
fibres, converging and forming a strong middle tendon.

188 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
2. Masseter (W).
From the malar pro-
cess of the os max-
illare, and the low-
er edges of the os
malæ, and of the
zygomatic process
of the os temporis.
Into the basis of the
coronoid process,
and that part of the
jaw which supports
that and the con-
dyloid process.
To raise and likewise
to move the jaw a
little forwards and
backwards.
3. Pterygoideus in-
ternus.
From the inner surface
of the outerwing of
the pterygoid pro-
cess of the os sphe-
noides, and from
the process of the
os palati that helps
to form the ptery-
goid fossa
Into the lower jaw on
its inner side and
near its angle.
To raise the lower jaw
and draw it a little
to one side.
4. Pterygoideus ex-
ternus.
From the external ala
of the pterygoid
process, a small part
of the adjacent os
maxillare, and a
ridge in the tem-
Into the fore part of
the condyloid pro-
cess of the lower
jaw, and likewise
of the capsular li-
gament.
To move the jaw for-
wards and to the
opposite side (X);
and at the same time
to prevent the liga-
ment of the joint
(W) So called from its use in chewing, its derivation being from μαδιδαομαι, manduco, "to eat."
(X) This happens when the muscle acts singly. When both act, the jaw is brought horizontally forwards.

189
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
poral of the 
os sphenoides.
from being pinch-
ed.
MUSCLES situated at
the fore part of the
neck.
1. Latissimus colli (Y). 
From the cellular 
membrane covering 
the pectoral, del-
toid, and trapezius
muscles.
Into the side of the
chin and integu-
ments of the cheek.
To draw the cheeks
and skin of the face
downwards; and
when the mouth is
shut, to draw all that
part of the skin to
which it is connect-
ed below the lower
jaw upwards.
2. Mastoideus (Z). 
From the upper part
of the sternum,and
from the upper and
fore part of the
clavicle.
Into the mastoid pro-
cess, and as far
back as the lamb-
doidal suture.
To move the head to
one side, or when
both muscles act, to
bend it forwards.
(Y) This broad and thin muscular expansion, which is situated immediately under the common integuments, is by Wins-
low named muscules cutaneus. Galen gave it the name of ωλατνσμα μνωδες (Platysma-myoides); the etymology of which
is from ωλατνσμος, dilatatio, and , μνς musculus, and ειδος, forma. 
(Z) This, on account of two origins, is by Albinus described as two distinct muscles, which he names sterno-mastoideus 
and cleido-mastoideus.

190 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion Use.
MUSCLES situated
between the trunk
and the os hyoides. 
1. Omo-hyoides (A) From the upper costa
of the scapula near
its niche; from part
of a ligament that
extends across this
niche, and some-
times by a few fi-
bres, from the co-
racoid process.
Into the basis of the
os hyoides.
To draw the os hyoi-
des in an oblique di-
rection downwards.
2. Sterno-hyoideus.
From the cartilage of
the first rib, the in-
ner and upper part
of the sternum ,and
a small part of the
clavicle.
Into the basis of the
os hyoides.
To draw the os hyoi-
des downwards.
3. Hyo-thyroideus.
From part of the ba-
sis and horn of the
os hyoides.
Into a rough oblique
line at the side of
the thyroid carti-
lage.
To raise the thyroid
cartilage, or depress
the os hyoides.
(A) This muscle does not always arise from the coracoid process, it seems to have been improperly named coraco-hyoides
by Douglas and Albinus. Winslow calls it omo-hyoideus, on account of its general origin from the scapula.

191
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
4. Sterno-thyroideus 
From between the
cartilages of the 1st
and 2d ribs at the
upper and inner
part of the sternum.
Immediately under
the hyo-thyroideus.
To pull the tyroid
cartilage down-
wards.
5. Crico-thyroideus.
From the anterior
part and side of the
cricoid cartilage.
Into the lower part
and inferior horn
of the thyroid car-
tilage.
To pull the cricoid
cartilage upwards
and backwards, or
the thyroid for-
wards and down- 
wards
—situated be-
tween the os hyoi-
des and lower jaw, 
1. Diagrasticus (B)
From a fossa at the
root of the mastoid
process, and like-
wise from the os
hyoides.
Into the lower and
anterior part of the
chin.
To draw the lower
jaw downwards.
2. Stylo-hyoideus (C) 
From the basis of the
styloid process.
Into the side and fore
part of the os hy-
oides near its base.
To draw the os hy-
oides obliquely up-
wards.
(B) From δις and ναςμρ (biventer), because it has two fleshy bellies with a middle tendon. This tendon passes through
the stylo-hyoideus.
(C) In some subjects we meet with another muscle, which from its having nearly the same origin, insertion and use as 
this, has been named stylo-hyoideus alter. 

192 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
3. Mylo-hyoideus (D)
From the inside of
the lower jaw, be-
tween the last dens
molaris and the
chin.
Into the basis of the
os hyoides.
To move the os hyoi-
des to either side,
forwards or up-
wards.
4. (E) Genio-hyoide-
us.
From the inside of the
chin.
Into the base of the
os hyoides.
To move the os hy-
oides forwards or
upwards.
5. Genio-glossus.
From the inside of the
chin.
Into the tongue and
basis of the os hy-
oides.
To move the tongue
in various direc-
tions.
6. Hyo-glossus (F)
From the horn, basis,
and appendix of the
os hyoides.
Into the tongue late-
rally.
To draw the tongue
downwards and in-
wards.
7. Lingualis.
Laterally from the
root of the tongue.
Into the extremity of
the tongue.
To shorten the ton-
gue and draw it
backwards.
8. Stylo-glossus.
From the styloid pro-
cess,and sometimes
also from a liga-
ment that extends
Into the side of the
tongue from the
root to near its tip.
To move the tongue
backwards and to
one side.
(D) So named from its arising near the dens molares (μνλοι) and its being inserted into the os hyoides.
(E) From γενειον, mentum, the "chin."
(F) From χερας, cornu, and γλωσσα, lingua, "the tongue." 
3

193
PART II. A TABLE OF THE MUSCLES.
from thence to the
angle of the lower
jaw.
9. Stylo-pharyngæ-
us.
From the basis of the
styloid process.
Into the side of the
pharynx and poste-
rior part of the thy-
roid cartilage.
To raise the thyroid
cartilage and pha-
rynx, and likewise
to dilate the latter.
To dilate and draw
the velum obliquely
downwards.
10. Circumflexus-
palati.
From near the bony
part of the Eusta-
chian tube, and
from the spinous
process of the os
sphenoides.
Into the semilunar
edge of the os palati
and the velum pen-
dulum palati (G).
11. Levator palati.
From the membra-
nous part of the
Eustachian tube,
and the extremity
of the os petrosum.
Into the velum pen-
dulum palati.
To pull the velum
backwards.
MUSCLES situated a-
bout the fauces,
1 Palato-pharyn-
gæus.
From the lower and
anterior part of the
cartilaginous extre-
Into the upper and
posterior part of the
thyroid cartilage.
To raise the pharynx
and thyroid carti-
lage, or to pull the
(G) This muscle in its course forms a round tendon, which, after crossing over a kind of hook formed by the inner plate
of the pterygoid process of the spenoid bone, expands into a tendinous membrane.
N

194 
PART II. A TABLE OF THE MUSCLES.  
Names. Origin. Insertion. Use.
mity of the Eusti-
chian tube (H); the
tendinous expan-
sion of the circum-
flexus palati; and
the velum pendu-
lum palati near the
basis and black part
of the uvula.
velum and uvula
backwards and 
downwards.
2. Constrictor isthmi 
faucium.
From near the basis 
of the tongue late-
rally.
Into the velum pen-
dulum palati, near
the basis and fore
part of the uvula.
To raise the tongue
and draw the ve-
lum towards it (I).					 
3. Azygos uvulæ.					 
From the end of the 
suture that unites 
the ossa palati.
Into the extremity of
the uvula.
To shorten the uvula,
and bring it for-
wards and upwards.
MUSCLES at the back
part of the pharynx 
1. Constrictor pharyn- 
gis superior.
From the cuneiform 
process of the oc- 
Into the middle of 
the pharynx.
To move the pharynx
upwards and for-
(H) The few fibres that arise from the Eustachian tube are described as a distinct muscle by Albinus, under the name
of salpingo pharyngeus. They serve to dilate the mouth of the tube.
(I) This muscle, and the palato-pharyngæus, likewise serve to close the passage into the fauces, and to carry the food
into the pharynx.

195
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
cipital bone; the
pterygoid process
of the os sphenei-
des, and from each 
jaw near the last
dens molares (K).
wards, and to com- 
pressits upper part. 
2. Constrictor pharyn-
gis medius (L).
From the horn and 
appendix of the os 
hyoides, and from
the ligament that
unites it with the
thyroid cartilage.
Into the middle of
the processus cunei-
formis of the occi-
pital bone, about
its middle and be-
fore the great fo-
ramen.
To draw theos hyoi-
des and pharynx
upwards, and to
compress the latter.
3. Constrictor pharyn-
gis inferior (M).
From the cricoid and
thyroid cartilages. 
Into the middle of
the pharynx.
To compress part of
the pharynx.
—about the 
glottis 
1. Crico-arytænoide- 
us lateralis. 
From the side of the 
cricoid cartilage.
Into the basis of the
arytænoid carti-
lage laterally.
To open the glottis.
(K) The three orders of fibres here mentioned, with a few others |derived from the tongue, have given occasion to
Douglas to describe them as four distinct muscles, under the names of cephalo-pharyngæus, mylo-pharyngæus, ptery-pharyn-
gæus and glosso-pharyngæus.
(L) Douglas makes two muscles of this, the hyo-pharyngæus and syndesmo-pharyngæus.
(M) The crico-pharyngæus, and thyro-pharyngus of Douglas.
N2

196 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
2. Crico-arytænoide-
us posticus.
From the cricoid car-
tilage posteriorly.
Into the basis of the
arytænoid carti-
lage posteriorly.
To open the glottis.
3. Arytænoideus ob-
liquis.
From the basis of one
of the arytænoid
cartilages.
Near the extremity of
the other arytæ-
noid cartilage.
To draw the parts it
is connected with
towards each other.
4. Arytænoideus
transversus.
From one of the ary-
tænoid cartilages
laterally.
Into the other arytæ-
noid cartilage late-
rally. 
To shut the glottis.
5. Thyreo-arytænoi-
deus.
From the posterior
and under part of
the thyroid carti-
lage.
Into the arytænoid
cartilage.
To draw the arytæ-
noid cartilage for-
wards.
6. Arytæno-epiglot-
tideus.
From the upper part
of the arytænoid
cartilage laterally.
Into the side of the
epiglottis.
To move the epiglot-
tis outwards.
7. Thyreo-epiglotti-
deus.
From the thyroid car-
tilage.
Into the side of the
epiglottis.
To pull the epiglot-
tis oblique down-
wards (N).
MUSCLES at the fore
part of the neck close 
to the vertebræ 
1. Rectus capitis in- 
ternus major.
From the anterior ex- 
tremities of the
Into the fore part of
the cuneiform pro-
To bend the head
forwards.
(N) When either this or the preceding muscle acts with its fellow, the epiglottis is drawn directly downwards upon the 
glottis.

197
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
transverse processes
of thefive lower-
most cervical ver-
tebræ.
cess of the os occi-
pitis.
2. Rectus capitis in
ternus minor
From the anterior
and upper part of
the first cervical
vertebra.
Near the basis of the
condyloid process
of the os occipitis.
To assist the last de-
scribed muscle.
3. Rectus capitis la-
teralis.
From the anterior
and upper part of
the transverse pro-
cess of the first cer-
vical vertebra
Into the os occipi-
tis, opposite to the
stylo-mastoid fora-
men.
To move the head to
one side.
4. Longus colli.
Within the thorax,
laterally from the
bodies of the three
uppermost dorsal
vertebræ ; from the
basis and fore part
of the transverse
processes of the first
and second dorsal
Into the second cer-
vical vertebra an-
teriorly.
To pull the neck to
one side (O).
(O) When both muscles act, the neck is drawn directly forwards.

198 
PART II. A TABLE OF THE MUSCLES. 
Names. Origin. Insertion. Use.
vertebræ, and of
the last cervical ver-
tebra ; and, lastly, 
from the anterior 
extremities of the 
transverse processes
of the 6th, 5th, 4th, 
and 3d cervical 
vertebræ.
—at the fore 
part of the abdo- 
men 
1. Obliquus externus. 
From the lower edges
of the eight infe-
rior ribs, near their
cartilages.
Into the linea alba 
(P), ossa pubis (Q), 
and spine of the 
ilium (R). 
To compress and sup- 
port the viscera, as- 
sist in evacuating 
the fæces and urine, 
(P) The linea alba is that tendinous expansion which reaches from the cartilago ensiformis to the os pubis. It is formed 
by the interlacement of the tendinous fibres of the oblique and transverse muscles, and on this account some anatomists 
have considered these as three digastric muscles. 
(Q) A little above the pubis the tendinous fibres of this muscle separate from each other, so as to form an opening call- 
ed the ring of the obliquus externus, and commonly, though improperly, the ring of the abdominal muscles, there being
no such aperture either in transversalis or obliquus internus. This ring in the male subject affords a passage to the sper-
matic vessels, and in the female to the round ligament of the uterus. 
(R) From the anterior and upper spinous process of the ilium, this muscle is stretched tendinous to the os pubis, and 
thus forms what is called by some Fallopius's, and by others Poupart's ligament. The blood-vessels pass under it to the 
thigh. 

199 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
draw down the ribs
and bend the trunk
forwards, or ob-
liquely to one side.
2. Obliquus internus. 
From the spinous pro- 
cess of the three
lowermost lumbar
vertebræ, the back
part of the os sa-
crum, the spine of
the ilium, and back
part of Fallopius's
ligament (T). 
Into the cartilages of										 
all the false ribs,										 
linea alba (S), and
fore part of
pubis.
To assist the obliquus
externus.
2. Transversalis.
From the cartilages 
of the seven inferi- 
or ribs ; the trans-
verse processes of
the last dorsal, and
four upper lumbar
vertebræ ; the in-
Into the linea alba
and cartilago ensi-
formis.
To compress the ab-
dominal viscera.
(S) The tendon formed by the upper par part of this, muscle in its way to the linea alba is divided into two layers. The
posterior layer runs under, and the anterior one over, the rectus muscle. 
(T) From this part it detaches some fibres which extends downwards upon the spermatic chord, and form what is de-
scribed as the cremaster muscle.

200 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
ner part of Fallo-
pius's ligament and
the spine of the i- 
lium. 
4. Rectus abdominis. 
From the upper edge
of the pubis and
the symphysis pu-
bis.
Into the cartilages of 
the 5th, 6th, and
7th ribs, and the
edge of the carti-
lago ensiformis (U).
To compress the fore 
part of the abdo- 
men, and to bend 
the trunk forwards. 
5. Pyramidalis (V).
From the anterior and
upper part of the
pubis.
Into the linea alba
and inner edge of
the rectus, com-
monly about two
inches above the
pubis.
To assist the lower
portion of the rect-
us.
MUSCLES at the fore 
part of the thorax 
1. Pectoralis Major. From the cartilagi- 
Into the upper and 
To draw the arm for-
(U) The fibres of the rectus are generally divided by three tendinous intersections. The two upper thirds of this muscle passing
between the tendinous layers of the obliquus internus, are inclosed as it were in a sheath; but at its lower part we find it im-
mediately contiguous to the peritonæum, the inferior portion of the tendon of the transversalis passing over tne rectus, and 
adhering to the anterior layer of the obliquus internus.
(V) This muscle is sometimes wanting.

201
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
nous ends of the
5th and 6th ribs;
anterior part of the
clavicle.
inner part of the
os humeri (W).
the sternum, and
wards or oblique-
ly forwards.
2. Subclavius. 
From the cartilage of
the first rib.
Into the under sur-
face of the cla-
vicle.
To move the clavicle
forward sand down-
wards and to assist in
raising the first rib.
3. Pectoralis minor 
(X).
From the upper edges
of the 3d 4th and
5th ribs.
Into the coracoid pro-
cess of the sca-
pula.
To move the scapula
for wards and down.
wards or to elevate
the ribs.
4. Serratus Magnus. 
From the eight supe-
rior ribs.
Into the basis of the
scapula.
To bring the scapula
forwards.
MUSCLES that con-
cur in forming the
thorax,
1. Diaphragma (Y).
(W) The fibres of this muscle pass towards the axilla in a folding manner, and with those of the latissimus dorsi form
the arm-pit.
(X) This and some other muscles derive their name serratus, from their arising by a number of tendinous or fleshy
digitations, resembling the teeth of a saw (serra).
(Y) For a description of the diaphragm, see Part IV. Sect. IV.

202 
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
2. Levatores costa- 
rum.
From the transverse
processes of the last
cervical and the
eleven upper dor-
sal vertebræ.
Into the upper side of 
each rib, near its
tuberosity.
To move the ribs up- 
wards and outwards.
3. Intercostales exter- 
ni. 
From the lower edge
of each upper rib.
Into the superior edge
of each lower rib. 
To elevate the ribs. 
4. Intercostales in- 
terni (A).
5. Sterno-costales (B). 
From the cartilagoen- 
Into the cartilages of 
To depress the carti-
(A) The origin, insertion, and use of the internal intercostals, are similar to those of the external. The reader, how- 
ever, will be pleased to observe, that the intercostales externi occupy the spaces between the ribs only from the spine to
their cartilages ; from thence to the sternum, there being only a thin membrane, which is spread over the intercostales in-
terni; and the latter, on the contrary, extend only from the sternum to the angles of each rib. 
The fibres of the external muscles run obliquely forwards; those of the internal obliquely backward. The difference
in the direction of their fibres induced Galen to suppose that they were intended for different uses; that the external in-
tercostals, for instance, serve to elevate, and the internal ones to depress the ribs. Fallopius seems to have been the first
who ventured to dispute the truth of this doctrine, which has since been revived by Boyle, and more lately still by Ham- 
berger, whose theoretical arguments on this subject have been clearly refuted by the experiments of Haller.
(B) These consist of four, and sometimes five distinct muscles on each side. Vesalius, and after him Douglas, and Al- 
binus, consider them as forming a single muscle, which, on account of its shape, they name triangularis. Verheyen,
Winslow, and Haller, more properly describe them as so many separate muscles, which, on account of their origin and 
insertion, they name sterno-costales.

203
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
siformis,and lower 
and middle part of
the sternum.
the 2d, 3d, 4th,
5th, and 6th ribs.
lages of the ribs.
—at the back
part of the neck
and trunk. 
1. Trapezius (C), or 
cucullaris.
From the middle of Into
the os occipitis,
and the spinous pro-
cesses of the two
inferior cervical,
and of all the dor-
sal, vertebræ (D).
Into the posterior 
half of the clavicle,
part of the acro-
mion, and the spine
of the scapula.
To move the scapula.
2. Rhomboideus (E). 
From the spinous pro- 
cesses of the three 
lowermost cervical,
and of all the dor-
sal vertebræ.
Into the basis of the
scapula.
To move the scapula.
upwards and back-
wards.
3. Latissimus dorsi.
From part of the 
spine of the os i- 
Into the os humeri,
at the inner edge of
To draw the os hu-
meri downwards
(C) So named by Riolanus, from Τραπεζα, on account of its quadrilateral shape. Columbus and others gave it the name
of cucullaris, from its resemblance to a monk's hood.
(D) The tendinous fibres of this muscle, united with those of its fellow in the nape of the neck, form what is called, the
ligamentum colli. 
(E) This muscle consists of two distinct portions, which are described as separate muscles by Albinus, under the names
of rhomboideus minor and rhombiodeus major.

204 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
lium, the spinous
processess of the os 
sacrum and lumbar
vertebræ, and of six
or eight of the dor-
sal vertebræ; also
from the four infe-
rior false ribs near 
their cartilages.
the groove for lod-
ging the long head
of the biceps muscle.
and backwards, and 
to roll it upon its 
axis.
4. Serratus inferior 
posticus. 
From the spinous pro-
cessess of the two 
lowermost dorsal,
and of three of the 
lumbar vertebræ.
Into the lower edges
of the three or four 
lowermost ribs near 
their cartilages.
To draw the ribs out-
wards, downwards,
and backwards.
5. Levator scapulæ.
From the transverse 
processess of the four 
uppermost vert-
bræ colli.
Into the upper angle
of the scapula.
To move the scapula
forwards, and up-
wards.
6. Serratus superior
posticus.
From the lower part
of the ligamentum
colli, the spinous 
process of the low-
ermost cervical ver-
tebra, and of the 
Into the 2d, 3d, and 
4th ribs.
To expand the tho-
rax.


205
PART II. A TABLE OF THE MUSCLES.
Name. Origin Insertion. Use.
two superior dorsal
vertebræ.
7. Splenius (F).
From the spinous pro-
cesses of the four
or five uppermost
vertebræ of the
back, and of the
lowermost cervical
vertebra.
Into the transverse 
processes of the two 
first cervical verte-
bræ, the upper and
back part of the
mastoid process, and
a ridge on the os
occipitis.
To move the head
backwards.
8. Complexus (G).
From the transverse 
processes of the four
or five uppermost
dorsal, and of the
fix lowermost cer-
vical vertebræ.
Into the os occipitis. 
To draw the
backwards.
9. Trachelo-mastoi-
deus (H).
From the transverse 
processes of the first 
dorsal vertebra, and
Into the mastoid pro-
cess. 
To draw the head
backwards.
(F) According to some writers, this muscle has gotten its name from its resemblance to the spleen; others derive it
from spenium splint.
(G) So named on account of its complicated structure.
(H) So named from its origin from the neck (Τραιχηλοις) and its insertion into the mastoid process.

206 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Inserion. Use.
four or five of the
lowermost, cervi-
cal vertebræ.
10. Rectus capitis po-
sticus major.
From the spinous pro- 
cess of the second
cervical vertebra.
Into the os occipitis.
To extend the head
and draw it back-
wards.
11. Rectus capitis po-
sticus minor.
From the first verte-
bra of the neck.
Into the os occipitis.
To assist the rectus
major.
12. Obliquus superior
capitis.
From the transverse
process of the first
cervical vertebra.
Into the os occipitis.
To draw the head
backwards.
13. Obliquus inferior
capitis.
From the spinous pro-
cess of the second
cervical vertebra.
Into the transverse
process of the first
cervical vertebra.
To draw the face to-
wards the shoulder,
and to move the first
vertebra upon the
second.
14. Sacro-lumbalis
(I) 
From the back 
of the os sacrum, 
spine of the ilium,
Into the lower edge
of each rib.
To draw the ribs 
downwards, move 
the body upon its 
as
(I) Several thin fasciculi of fleshy fibres arise from the lower ribs, and terminate in the inner side of this muscle. Steno
names them masculi ad sacro lumbalem accessorii. The sacro-lumbalis likewise sends off a fleshy slip from its upper part,
which by Douglas and Albinus is described as a distinct muscle, under the name of cervicalis descendens. Morgagni has
very properly considered it as a part of the sacro-lumbalis.

207
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
spinous processes 
and roots of the 
transverse processes 
of the vertebræ of 
the loins. 
axis, assist in erect- 
ing the trunk and 
turn the neck back-
wards, or to one
side.
15. Longissimus dor- 
si (K). 
The same as that of
the sacro-lumbalis. 
Into the transverse
processes of the dor- 
sal vertebræ. 
To stretch the verte-
bræ of the back, 
and keep the trunk 
erect. 
16. Spinalis dorsi. 
From the spinous pro-
cesses of the upper-
most lumbar and
lowermost dorsal 
vertebræ.
Into the spinous pro-
cesses of the nine 
superior dorsal ver- 
tebræ 
To extend the verte- 
bræ.
17. Semi-spinalis dor- 
si.
From the transverse 
processes of the 7th, 
8th, 9th, and 10th
vertebræ of the 
back.
Into the spinous pro- 
cesses of the four
uppermost dorsal,
and lowermost of the
cervical vertebræ.
To extend the spine 
obliquely back-
wards. 
(K) At the upper part of this muscle a broad thin layer of fleshy fibres is found crossing, and intimately adhering to it.
This portion, which is described by Albinus, under the name of transversalis cervicis, may very properly be considered
as an appendage to the longissimus dorsi. It arises from the transverse processes of the five or six superior dorsal vertebræ,
and is inserted into the transverse processes of the six inferior cervical vertebræ. By means of this appendage the longissi
mus dorsi may serve to move the neck to one side, or obliquely backwards. 

208 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use. 
18. Multisidus Spi- From the os facrum, 
næ (L). 
From the os sacrum,
ilium, oblique and 
transverse processes
of the lumbar ver- 
tebræ, transverse 
processes of the dor- 
sal, and four of the 
cervical vertebræ. 
Into the spinous pro- 
cesses of the lum-
bar, dorsal, and six 
of the cervical ver- 
tebræ. 
To extend the back
and draw it back-
wards, or to one
side.
19. Semi spinalis col- 
li.
From the transverse 
processes of the five
or six uppermost
dorsal vertebræ.
Into the spinous pro- 
cesses of the 2d,
3d, 4th, 5th, and 
6th cervical ver- 
tebræ.
To stretch the neck 
obliquely back- 
wards.
20. Scalenus (M). 
From the transverse 
processes of the five 
inferior cervical
vertebræ.
Into the upper and
outer part of the
first and second ribs.
To move the neck 
forwards, or to one 
side. 
(L) Anatomists in general have unnecessarily multiplied the muscles of the spine. Albinus has the merit of having in- 
troduced greater simplicity into this part of myology. Under the name of multifidus spinæ, he has very properly included 
those portions of muscular flesh intermixed with tendinous fibres, situated close to the back part of the spine, and which
described by Douglas under the names of transversales colli, dorsi, & lumborum. 
(M) The ancients gave it this name from its resemblance to an irregular triangle (σχαληνος). It consists of three fleshy 
portions. The anterior one affords a passage to the axillary artery, and between this and the middle portion we find the 
nerves going to the upper extremities. The middle is in part covered by the posterior portion, which is the longest and
thinnest of the three. 

209
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
21. Inter-spinalis (N). 
From the upper part
of each of the spi-
nous processes of
the six inferior cer-
vical vertebræ.
Into the under part of 
each of the spinous 
processes of the ver- 
tebræ above.
To draw the spinous
processes towards
each other.
22.Inter-transversa-
les (O).
From the upper part
of each of the trans-
verse processes of
the vertebræ.
Into the under part of
each of the trans- 
verse processes of 
the vertebræ above.
To draw the trans-
verse processes to-
wards each other.
MUSCLES within the
cavity of the abdo-
men, on the ante-
rior and lateral
parts of the spine,
1. Psoas parvus (P).
From the sides and
transverse processes
of the uppermost
lumbar vertebra,
and sometimes of
Into the brim of the 
pelvis, at the junc- 
tion of the os pubis
with the ilium.
To bend the loins for-
wards.
(N) In generality of anatomical books we find these muscles divided into inter-spinalis cervicis, dorsi, and lumborum,
but we do not find any such muscles either in the loins or back.
(O) These muscles are to be found only in the neck and loins; which have been described, as the inner-transversales
dorsi being rather small tendons than muscles.
(R) This and the following pair of muscles derive their name of psoas from το α, lumbus, on account of their situation
at the anterior part of the loins.

210 
PART II. A TABLE of the MUSCLES. 
Name. Origin. Insertion. Use.
the lowermost dor-
sal vertebra.
2. Psoas magnus. 
From the bodies and 
transverse processes
of the last dorsal,
and all the lumbar 
vertebræ.
Into the os femoris, a 
little below the tro-
chanter minor.
To bend the thigh
forwards.
3. Iliacus internus. 
From the inner lip,
hollow part, and 
edge of the os 
ilium.
In common with the 
psoas magnus.
To assist the psoas
magnus.
4. Quadratus lumbo-
rum (Q).
From the posterior 
part of the spine 
of the ilium.
Into the transverse
processes of the four 
uppermost lumbar
vertebræ, the infe-
rior edge of the last 
rib, and the side of 
the lowermost dor-
sal vertebra.
To support the spine,
or to draw it one 
side.
5. Coccygæus.
From the posterior
and inner edge of 
Into the lower part
of the os sacrum,
To draw the os coc-
cygis forwards and 
(Q) So called from its shape, which is that of an irregular square.

211
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
the spine of
ischium.
and almost the
whole length of the
os coccygis late-
rally.
inwards (R).
MUSCLES on the sca-
pula and upper part
of the os humeri,
1. Deltoides (S).
From the clavicle,
processus acromion,
and spine of the
scapula.
Into the anterior and 
middle part of the
os humeri.
To raise the arm. 
2. Supra-spinatus.
From the basis, spine, 
and upper costa of 
the scapula.
Into a large tuberosi-
ty at the head of
the os humeri.
To raise the arm.
3. Infra-spinatus.
From the base and 
spine of the scapu- 
la. 
Into the upper and
middle part of the
tuberosity.
4. Teres minor (T).
From the inferior co- 
sta of the scapula. 
Into the lower part of
the tuberosity.
To assist the infra spi-
natus.
5. Teres major.
From the inferior 
Into the ridge at the
To assist in the rota-
(R) Some of the fibres of this muscle are united with those of the levator ani, so that it assists in closing the lower part
of the pelvis.
(S) So named from its supposed resemblance to the Greek Δ reversed. 
(T) This and the following pair are called teres, from their being of a long and round shape.
O2

212 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
angle, and inferior
costa of the scapu-
la.
inner side of the
groove formed for
the long head of 
the biceps.
tory motion of the 
arm.
6. Subscapularis.
From the basis, supe-
rior and Inferior co-
sta of the scapula.
Into the upper part of 
a small tuberosity
at the head of the 
os humeri.
To roll the arm in-
wards.
7. Coraco-brachia-
lis (U)
From the coracoid
process on the sca-
pula.
Into the middle and 
inner side of the os 
humeri.
To roll the arm for-
wards and upwards.
MUSCLES on the os
humeri, 
1. Biceps flexor cubi-
ti.
By two heads, one
from the coracoid
process, and the o-
ther, or long head,
from the upper and
outer edge of the
glenoid cavity of
the scapula.
2. Brachialis internus 
From the os humeri,
below, and at each
Into a small tuberosity
at the fore part of 
To assist in bending
the fore-arm.
(U) This muscle affords a passage to the musculo-cutaneous nerve.

213
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
side of the tendon
the coronoid pro-
cess of the ulna.
3. Triceps extensor
cubiti.
By three heads: the 
first, from the infe-
rior costa of the 
scapula; the second 
from the upper and 
outer part of the os 
humeri; and the 
third, from the 
back part of that 
bone.
Into the upper and 
outer part of the 
olecranon.
To extend the fore-
arm.
MUSCLES on the fore-
arm, 
1. Supinator longus. 
From the outer ridge 
and anterior surface 
of the os humeri, a 
little above its out-
er condyle.
Into the radios near
its styloid process.
To assist in turning
the palm of the
hand upwards.
2. Extensor carpi ra-
dialis longus.				 
Immediately below 
the origin of the 
supinator longus. 
Into the upper part
of the metacarpal 
bone of the fore-finger.
To extend the wrist. 
3. Extensor capri ra- 
dialis brevis. 
From the outer and
lower part of the
Into the upper part
of the metacarpal
To assist the extensor
longus.

214 
PART II. A TABLE OF THE MUSCLES. 
outer condoyle of 
the os humeri, and 
the upper part of 
the radius.
bone of the middle 
finger.
4. Extensor digito-
run communis.
From the outer con-
dyle of the os hu-
meri.
Into the back part of 
all the bones of the 
fore finger. 
To extend the fingers.
5. Extensor minimi 
digiti. 
From the outer con-
dyle of the os hu- 
meri.
Into the bones of the 
little finger.
To extend the little 
finger.
6. Extensor carpi ul- 
naris. 
From the outer con-
dyle of the os hu-
meri.
Into the metacarpal
bone of the little 
finer.
To assist in extending 
the wrist.
7. Anconæus (V).
From the outer con-
dyle of the os hu-
meri. 
Into the outer edge 
of the ulna.
To extend the fore-
arm.
8. Flexor carpi ulna-
ris.
From the inner con-
dyle of the os hu-
meri, and anterior 
edge of the olecra-
non (W).
Into the os pisiforme. 
To assist in bending 
the hand.
9. Palmaris longus.
From the inner con-
Into the internal an- 
To bend the hand. 
(V) So called αΓχων, cubitus.
(W) Between the two origins of this muscle we find the ulnor nerve going to the fore-arm.

215
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use. 
dyle of the os hu- 
meri. 
nular ligament, and
aponeurosis palma- 
ris (X). 
10. Flexor carpi ra- 
dialis.
From the inner con-
dyle of the os hu-
meri.
Into the metacarpal 
bone of the fore
finger.
To bend the hand.
11. Pronator radii 
teres. 
From the outer con-
dyle of the os hu- 					 
meri, and coronoid 
process of the ulna. 
Into the anterior and 
convex edge of the
radius near its 
middle.
To roll the hand in-
wards.
12. Flexor sublimis 
perforatus (Y). 
From the inner con-
dyle of the os hu- 
meri, inner edge of 
the coronoid pro- 
cess of the ulna, 
and upper and an- 
terior part of the 
radius. 
Into the second bone
of each finger.		
To bend the second
joint of the finger.
(X) The aponeurosis palmaris is a tendinous membrane that extends over the palm of the hand. Some anatomists have 
supposed it to be a production of the tendon of this muscle, but without sufficient grounds; for in some subjects we find. 
the palmaris longus inserted wholly into the annular ligament, so as to be perfectly distinct from its aponeurosis; and it now
and then happens, that no palmaris longus is to be found, whereas this expansion is never deficient. 
(Y) This muscle is named perforatus, on account of the four tendons in which it terminates, being perforated by those 
of another muscle, the perforans.

216 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
13. Supinator radii
brevis.
From the outer con-
dyle of the os hu-
meri, and posterior 
surface and outer 
edge of the ulna.
Into the anterior, in-
ner, and upper part 
of the radius. 
To roll the radius 
outwards.
14. Abductor polli-
cis longus.
From the middle and 
back part of the 
ulna, interosseous 
ligament, and ra- 
dius. 
By two tendons into 
the os trapezium,
and first bone of 
the thumb.
To stretch the first 
bone of the thumb
outwards.
15. Extensor minor 
pollicis.
From the back part 
of the ulna, and in-
terosseous ligament
and radius. 
Into the convex part 
of the second bone 
of the thumb.
To extend the second 
bone of the thumb
obliquely outwards.
16. Extensor major
pollicis.
From the back of the 
ulna and interosse- 
ous ligament. 
Into the third and
last bone of the 
thumb. 
To stretch the thumb
obliquely back-
wards.
17. Indicator. 
From the middle of 
the ulna.
Into the metacarpal 
bone of the fore-
finger.
To extend the fore- 
finger.
18. Flexor profundus 
perforans.
From the upper and 
fore part of the 
ulna, and interos-
seous ligament. 
Into the fore part of 
the last bone of 
each of the fingers.
To bend the last joint 
of the fingers.

217
Part II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
19. Flexor longus 
pollicis. 
From the upper and
fore part of the 
radius.	
Into the last joint of		
the thumb.
To bend the last joint 
of the thumb.
20. Pronator radii 
quadratus. 
From the inner and 
lower part of the 
ulna.
Into the radius, op-
posite to its origin.
To roll the radius in-
wards and of course
to assist in the pro-
nation of the hand.
MUSCLES on the hand, 
I. Lumbricales (Z). 
From the tendons of 
the perforans. 
Into the tendons of 
the extensor digi- 
torum communis. 
To bend the first, and 
to extend the two 
last joints of the 
fingers (A). 
2. Abductor brevis 
pollicis. 
From the fore part
of the internal an-
nular ligament, os 
scaphoides, and one 
of the tendons of 
the abductor lon- 
gus pollicis. 
Into the outer side of
the 2d bone of the
thumb, near its
root. 
To move the thumb 
from the fingers.
3. Opponens pollicis. 
From the inner and 
anterior part of the
internal annular li-
Into the first bone of 
the thumb. 
To move the thumb 
inwards and to turn 
it upon its axis. 
(Z) So named from their being shaped somewhat like the lumbricus or earth-worm. 
(A) Fallopius was the first who remarked the two opposite uses of this muscle. Their extending power is owing to their 
connection with the extensor communis.

218 
PART II. A TABLE OF THE MUSCLES.  
Name. Origin. Insertion. Use.
gament, and from
the os scaphoides.
4. Flexor brevis pol-
licis.
From the os trapezoi-
des, internal annu-
lar ligament, os
magnum, and os
unciforme.
Into the ossa sesamoi- 
dea and second 
bone of the thumb.
To bend the second
joint of the thumb.
5. Adductor pollicis.
From the metacarpal
bone of the middle
finger.
Into the basis of the 
second bone of the 
thumb.
To move the thumb
towards the fingers
6. Adductor indices.
From the inner side
of the first bone of
the thumb, and
from the os trape-
zium.
Into the first bone of 
the fore finger po- 
steriorly. 
To move the fore-fin -
ger towards the
thumb.
7. Palmaris brevis.
From the internal an-
nular ligament,and
aponeurosis palma-
ris.
Into the os pisiforme, 
and the skin cover- 
ing the abductor 
minimi digiti.
To contract the palm
of the hand.
8. Adductor minimi
digiti.
From the internal an-
nular ligament and
os pisiforme.
Into the side of the 
first bone of the 
little finger. 
To draw the little
finger from the rest.
9. Flexor parvus mi-
nimi digiti.
From the os uncifor-
me and internal an-
nular ligament.
Into the first bone of 
the little finger. 
To bend the little fin-
ger.

219
PART II. A TABLE OF THE MUSCLES.
Name. Use. Insertion. Use.
10. Adductor meta-
carpi minimi digiti.
From the os uncifor-
me and internal an-
nular ligament.
Into the metacarpal
bone of the little
finger.
To move that bone
towards the rest.
11. Interossei interni. 
Situated between the
metacarpal bones.
Into the roots of the
fingers.
To extend the fingers
and move them to-
wards the thumb
(B).
12. Interossei externi.
Situated between the
matacarpal bones
on the back of the
hand.
Into the roots of the
fingers.
To extend the fin-
gers; but the first
draws the middle
finger inwards, the 
second draws it out- 
wards, and the third
draws the ring fin- 
ger inwards. 
MUSCLES at the back
part of the pelvis,
and upper part of
the thigh, 
1. Glutæus (C) max-
imus. 
From the spine of the
illium, posterior sa-
cro ischiatic liga-
ments, os sacrum,
and os coccygis.
Into the upper part
of the linea aspera
of the os femoris.
To extend the thigh
and draw it out-
wards.
(B) The third interosseus internus (for there are four of the externi and three of the interni) differs from the rest in
drawing the middle finger from the thumb. (C) From γλδτος, nates.


220 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use. 
2. Glutæus medius. 
From the spine and
superior surface of 
the ilium. 
Into the outer and 
back part of the
great trochanter of
the os femoris.
To draw the thigh 
outwards and a lit- 
tle backwards, and 
when it is bended, 
to roll it. 
3. Glutæus minimus. 
From the outer sur-
face of the ilium 
and the border of 
its great niche. 
Into the upper and
anterior part of the 
great trochanter.
To assist the former.
4. Pyriformis (D). 
From the anterior 
part of the os sa-
crum. 
Into a cavity at the 
root of the trochan-
ter major.
To roll the thigh out- 
wards. 
5. Gemini (E). 
By two portions, one 
from the outer sur- 
face of the spine
of the ischium; 
the other from the
tuberosity of the
ischium and poste- 
rior sacro-ischiatic
ligament.
Into the same cavity 
as the pyriformis. 
To roll the thigh out-
wards, and likewise 
to confine the ten- 
don of the obtura- 
tor internus, when 
the latter is in ac- 
tion. 
(D) So named from its pear-like shape. 
(E) The two portions of this muscle having been described as two distinct muscles by some anatomists, have occasioned 
it to be named gemini. The tendon of the obturator internus runs between these two portions. 

221
PART II. A TABLE OF THE MUSCLES.
Names. Origin. Insertion. Use. 
6. Obturator internus. 
From the superior 
half of the inner 
border of the fo- 
ramen thyroideum. 
Into the same cavity 
with the former.
To roll the thigh out- 
wards. 
7- Quadratus (F) fe- 
moris.
From the tuberosity 
of the ischium.
Into a ridge between 
the trochanter ma-
jor and trochanter
minor.
To move the thigh
outwards. 
MUSCLES on the 
thigh (G), 
1. Biceps flexor cru- 
ris.
By two heads; one 
from tuberosi-
ty of the ischium,
the other from the 
linea aspera near 
the insertion of the 
glutæus maximus.
Into the upper and 
back part of the fi- 
bula (H). 
To bend the leg. 
2. Semi-tendinosus. 
From the tuberosity 
of the ischium. 
Into the upper and 
inner part of the
tibia.
To bend and draw the 
leg inwards. 
(F) This muscle is not of the square shape its name would seem to indicate. 
(G) The muscles of the leg and thigh are covered by a broad tendinous membrane called fascia lata, that surrounds 
them in the manner of a sheath. It is sent off from the tendons of the glutæi and other muscles, and dipping down be-
tween the muscles it covers, adheres to the linea aspera, and spreading over the joint of the knee, gradually disappears 
on the leg. It is thickest on the inside of the thigh. 
(H) The tendon of this muscle forms the outer-ham-string. 

222 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
3. Semi-membrano-
sus (I).
From the tuberosity
of the ischium.
Into the upper and 
back part of the 
head of the tibia.
To bend the leg.
4. Tensor vaginæ fe-
moris.
From the superior and 
anterior spinous pro-
cess of the ilium.
Into the inner side of 
the fascia lata,
which covers the 
outside of the thigh.
To stretch the fascia.
5. Sartorius.
From the superior 
and anterior spinous 
process of the ili- 
um.
Into the upper and in- 
ner part of the ti- 
bia.
To bend the leg in-
wards (K).
6. Rectus.
By two tendons; one 
from the anterior 
and inferior spi- 
nous process of the
ilium ; the other
from the posterior
edge of the coty-
loid cavity.
Into the upper and 
fore-part of the pa-
tella.
To extend the leg.
7. Gracilis.
From the fore-part 
of the ischium and 
pubis. 
Into the upper and 
inner part of the
tibia.
To bend the leg.
(I) So named on account of its origin, which is by a broad flat tendon three inches long.
(K) Spigelius was the first who gave this the name sartorius, or the taylor's muscle, its use in crossing the legs.

223
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
8. Vastusexternus (L) 
From the anterior and 
lower part of the 
great trochanter, 
and the outer edge
of the linea as-
pera.
To the upper and
outer part of
patella.
To extend the leg.
9. Vastus internus.
From the inner edge 
of the linea aspera, 
beginning between 
the fore-part of the
os femoris and the
root of the lesser
trochanter. 
Into the upper and 
inner part of the
patella.
To extend the leg.
10. Cruræus (M) 
From the outer and 
anterior part of 
the lesser trochan-
ter.
Into the upper part of 
the patella.
To extend the leg.
11. Pectinalis.
From the anterior 
edge of the os pu-
bis, or pectinis, as it
is sometimes called. 
Into the upper and 
fore part of the li-
nea aspera.
To draw the thigh
inwards, upwards, 
and to roll it a little 
outwards. 
(L) The vastus externus, vastus internus, and cruræus, are so intimately connected with each other, that some anato-
mists have been induced to consider them as a triceps, or single muscle with three heads. 
(M) Under the cruræus we sometimes meet with two small muscles, to which Albinus has given the name of sub-cruræi.
They terminate on each side of the patella, and prevent the capsular ligament from being pinched. When they are want-
ing, which is very often the case, some of the fibres of the cruræus are found adhering to the capsula.

224 
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
12. Adductor longus 
Femoris (N).
From the upper and 
fore part of the os 
pubis.
Near the middle
and back part of
the linea aspera.
To draw the thigh
inwards, upwards,
and to roll it a little
outwards.
13. Adductor brevis 
femoris.
From the fore part of 
the ramus of the os
pubis.
Into the inner and
upper part of the
linea aspera. 
To draw the thigh
inwards, upwards,
and to roll it a little
outwards.
14. Adductor mag-
nus femoris.
From the lower and
fore part of the ra-
mus of the os pu-
bis.
Into the whole
length of the li-
nea aspera.
To draw the thigh
inwards, upwards,
and to roll it a little
outwards.
15. Obturator exter-
nus.
From part of the ob- 
turator ligament, 
and the inner half 
of the circumfe-
rence of the fora-
men thyroideum.
Into the os femoris 
near the root of
the great trochan-
ter.
To move the thigh
outwards in an ob-
lique direction, and
likewise to bend
and draw it in-
wards.
MUSCLES on the leg,
1. Gastrocnemius (O) 
externus.
By two heads; one 
from the inner con-
dyle,the other from
the outer condyle
of the os femoris.
By a great round ten- 
don, common to
this and the follow-
ing muscle.
To extend the foot
(N) This and the two following muscles have been usually, but improperly, considered as forming a single muscle with
three heads, and on that account named triceps femoris.
(O) sαsροχγημια sura, the calf of the leg."
3

225
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
2. Gastrocnemius (P) 
internus. 
By two heads; one 
from the back part 
of the head of the
fibula, the other
from the upper and
back part of the
By a large tendon 
(the tendo achillis)
common to this and
the former muscle,
into the lower and
back part of the os
calcis. 
To extend the foot.		
3. Plantaris (Q)			 
From the upper and
posterior part of the 
outer condyle of 
the os femoris.
Into the inside of the 
back part of the os
calcis.
To assist in extending
the foot.
4. Popliteus (R) 
From the outer con- 
dyle of the thigh. 
Into the upper and 
inner part of the 
tibia.
To assist in bending
the leg and rolling
it inwards.
5. Flexor longus digi-
torum pedis (S) 
From the upper and 
inner part of the 
tibia.
By four tendons,
which, after passing
through the perfo-
rations in those of 
the flexor digito-
To bend the last joint
of the toe.
(P) This muscle is by some anatomists named soleus, on account of its being shaped like the sole-fish.
(Q) This muscle has gotten the name of plantaris, from its being supposed to furnish the aponeurosis that covers the
sole of the foot; but it does not in the least contribute to the formation of that tendinous, expansion.
(R) So called on account of its situation at the ham (poples).
(S) This muscle, about the middle of the foot, unites with a fleshy mass, which, from its having first been described
by Sylvius, is usually called massa carnea JACOBI SYLVII.
P 

226 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
rum brevis, are in-
serted into the last 
bone of all the toes
except the great
toe.
6. Flexor longus pol- 
licis pedis.
From the back part,
and a little below
the head of the fi-
bula.
Into the last bone of 
the great toe.
To bend the great
toe.
7. Tibialis posticus.					 
From the back part
and outer edge of
the tibia, and like-
wise from the in-
terosseous ligament
and adjacent part
of the fibula.
8. Peroneus longus.
From the outer side
of the head of the
tibia, and also from
the upper, anterior
and outer part of
the perone or fibu-
la, to which it ad-
heres for a consi-
derable way down.
Into the metatarsal
bone of the great 
toe.
To move the foot out-
wards.

227
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Inseation. Use. 
9. Peroneus brevis. 
From the outer and 
fore-part of the fi-
bula.
Into the metatarsal 
bone of the little
toe.
To assist the last de- 
scribed muscle. 
10. Extensor longus 
digitorum pedis.
From the upper, out- 
er, and fore part 
of the tibia, inter- 
osseous ligament, 
and inner edge of 
the fibula. 
By four tendons into 
the first joint of the
smaller toes. 
To extend the toes.	
11. Peroneus tertius. 
From the fore-part 
bone of the little
toe.
Into the metatarsal 
of the lower half 
of the fibula, and 
from the interos- 
seous ligament. 
To bend the foot. 											 
12. Tibialis amicus.
From the upper and 
fore part of the ti- 
bia.
Into the os cunei-
forme internum.
To bend the foot. 
13. Extensor proprius 
pollicis pedis.
From the upper and 
fore part of the ti-
bia.
Into the convex sur- 
face of the bones of 
the great toe.
To extend the great
toe.
MUSCLES on the foot, 
1. Extensor brevis di- 
gitorum pedis.
From the upper and 
anterior part of the
os calcis. 
By four tendons; one 
of which joins the
tendon of the ex-
ternus longus polli-
To extend the toes. 
P2

228 
PART II. A TABLE OF THE MUSCLES. 
Name. Origin. Insertion. Use.
cis, and the other 
three the tendons
of the extensor di-
gitorum longus.
2. Flexor brevis digi-
torum pedis.
From the lower part 
of the os calcis.
By four tendons,
which, after af-
fording a passage
to those of the flex-
or longus, are in-
serted into the se-
cond phalanx of 
each of the small 
toes.
To bend the second
joint of the toes.
3. Abductor pollicis 
pedis.
From the inner and 
lower part of the 
os calcis.
Into the first joint of 
the great toe. 
To move the great 
toe from the other 
toes.
4. Abductor minimi 
digiti.
From the outer tuber-
cle of the os calcis,
the root of the me-
tatarsal bone of the 
little toe, and also
from the aponeuro-
sis plantaris.
Into the outer side
of the first joint of 
the little toe.
To draw the little toe
outwards.

229
PART II. A TABLE OF THE MUSCLES.
Name. Origin. Insertion. Use.
5. Lumbricalis pedis. 
From the tendons of 
the flexor longus
digitorum pedis.
Into the tendinous 
expansion at the
upper part of the
toes.
To draw the toes in- 
wards.
6. Flexor brevis pol-
licis pedis.
From the inferior and
anterior part of the
os calcis, and also
from the inferior
part of the os cu-
neiforme externum 
By two tendons into 
the first joint of 
the great toe.
To bend the first joint
of the great toe. 
7. Adductor pollicis
pedis.
From near the roots
of the metatarsal
bones of the 2d,
3d, and 4th toes.
Into the outer os se- 
samoideum, or first 
joint of the great 
toe.
To draw the great toe
nearer to the rest,
and also to bend it.
8. Transversales pe-
dis.
From the outer and
under part of the
interior end of the
metatarsal bone of
the little toe.
Into the inner os se- 
samoideum, and an-
terior end of the
metatarsal bone of
the great toe.
To contract the foot.
9. Flexor brevis mi-
nimi digiti pedis.
From the basis of the 
metatarsal bones of 
the little toe.
Into the first jont of 
the little toe.
To bend the little toe.

230 
PART II. A TABLE OF THE MUSCLES. 
10. Interossei pedis
interni ( T ).
Situated between the 
metatarsal bones.
—exter-
ni (U).
(T) The interossei interni are three in number ; their use is to draw the smaller toes towards the great toe.
(U) the interossei externi are four in number ; the first serves to move the fore-toe towards the great toe: and the rest 
move the toes outwards. All the interossei assist in extending the toes.

231
Part II. OF THE MUSCLES.
EXPLANATION of PLATES XXIII and XXIV.
PLATE XXIII.
FIG. 1. The MUSCLES immediately under
the common teguments on the anterior part of
the body are represented on the right side; and
on the left side the MUSCLES are seen which
come in view when the exterior ones are taken
away.
A, The frontal muscle. B, The tendinous
aponeurosis which joins it to the occipital; hence
both named occipito-frontalis. C, Attolens au-
rem. D, The ear. E, Anterior auris. FF,
Orbicularis palpebrarum. G. Levator labii su-
perioris alæque nasi. H, Levator anguli oris.
I, Zygomaticus minor. K, Zygomaticus ma-
jor. L, Massater. M, Orbicularis oris. N,
Depressor labii inferioris. O, Depressor anguli
oris. P, Buccinator. QQ, Platysma myoides.
R R, Sterno-cleido-mastoidæus. S, Part of the
trapezius. T, Part of the scaleni.
SUPERIOR EXTREMITY.—U, Deltoides. V,
Pectoralis major. W, Part of the latissimus dor-
si. X X, Biceps flexor cubiti. YY, Part of
the brachialis externus. ZZ, The beginning of
the tendinous aponeurosis (from the biceps),
which is spread over the muscles of the fore-arm.
a a, Its strong tendon inserted into the tubercle
of the radius, b b, Part of the brachialis inter-
nus. c, Pronator radii teres, d. Flexor carpi
radialis.

232 
Part II. OF THE MUSCLES. 
radialis. e, Part of the flexor carpi ulnaris. f,
Palmaris longus. g, Aponeurosis palmaris. 3,
Palmaris brevis. 1, Ligamentum carpi annulare.
2 2, Abductor minimi digiti. h, Supinator radii
longus. i, The tendons of the thumb. k, Ab-
ductor pollicis. l, Flexor pollicis longus. mm,
The tendons of the flexor sublimis perforatus,
profundus perforans, and lumabricales.—The
sheaths are entire in the right hand,—in the left
cut open to show the tendons of the flexor pro-
fundus perforating the sublimis.
MUSCLES not referred to—in the left superior
extremity.—n, Pectoralis minor, seu serratus an-
ticus minor. o, The two heads of (xx) the
biceps. p, Coraco-brachialis. qq, The long
head of the triceps extensor cubiti. rr, Teres
major. ff, Subscapularis. tt, Extenfores ra-
diales, u, Supinator brevis. v, The cut extre-
mity of the pronator teres. w, Flexor sublimis
perforatus. x, Part of the flexor profundus. y,
Flexor pollicis longus. z, Part of the flexor pol-
licis brevis. 4, Abductor minimi digiti. 5, The
four lumbricales.
TRUNK.—6, Serrated extremities of the ser-
ratus anticus major, 77, Obliquus externus ab-
dominis. 88, The linea alba. 9, The umbi-
licus. 10, Pyramidalis. 1111, The sperma-
tic cord. On the left side it is covered by the
cremaster. 1212, Rectus abdominis. 13,
Qbliquus internus. 1414, &c. Intercostal
muscles.
INFERIOR 

233
PART II. OF THE MUSCLES.
INFERIOR EXTREMITIES.—aa, The gra-
cilis. b b, Parts of the triceps, cc, Pectialis.
dd, Psoas magnus. ee. Iliacus internus. f,
Part of the gluteus medius. g, Part of the glu-
teus minimus. h, Cut extremity of the rectus
cruris. ii, Vastus externus. k, Tendon of the
rectus cruris. ll, Vastus internus. * Sartorius
muscle. ** Fleshy origin of the tensor vaginæ
fæmoris or membranosus. Its tendinous apo-
neurosis covers (i) the vastus externus in the
right side. mm, Patella. nn, Ligament or
tendon from it to the tibia. o, Rectus cruris.
p, Cruræus. qq, The tibia, rr, Part of the
Gemellus or gastrocnemius externus.* sss, Part
of the soleus or gastrocnemius internus. t, Tibi-
alis anticus. u, Tibialis posticus. vv, Peronæi
muscles. ww, Extensor longus digitorum pe-
dis, xx, Extensor longus pollicis pedis. y, Ab-
ductor pollicis pedis.
FIG 2. The MUSCLES, GLANDS, &c. of the
Left Side of the face and neck, after the com-
mon Teguments and Platysma myoides have
been taken off.
a, The frontal muscle. b, Temporalis and
temporal artery. c, Orbicularis palpebrarum.
d, Levator labii superioris alæque nasi. e, Le-
vator anguli oris. f, Zygomaticus. g, Depressor
labii inferioris. h, Depressor anguli oris. i, Buc-
cinator, k, Masseter. ll, Parotid gland. m, Its
duct.

234 
Part II. OF THE MUSCLES. 
duct. n, Sterno-cleido-mastoidæus. o, Part of
the trapezius. p, Sterno-hyoidæus. q, Sterno
thyroidæus. r, Omo-hyoidæus. s, Levator
scapulæ. tt , Scaleni. u, Part of the splenius.
FIG. 3. The MUSCLES of the Face and Neck in
view after the exterior ones are taken away.
aa, Corrugator supercilii. b, Temporalis. c,
Tendon of the levator palpebræ superioris. d,
Tendon of the orbicularis palpebrarum. e, Mas-
seter. f, Buccinator. g, Levator anguli oris.
h, Depressor labii superioris alæque nasi. i, Or-
bicularis oris. k, Depressor anguli oris. l, Mus-
cles of the os hyoides. m, Sterno-cleido-masto-
idæus.
FIG. 4. Some of the MUSCLES of the Os Hy-
oides and Submaxillary Gland.
a, Part of the masseter muscle. b, Posterior
head of the digrastic. c, Its anterior head. dd,
Sterno-hyoidæus. e, Omo-hyoidæus. f, Stylo-
hyoidæus. g, Submaxillary gland in situ.
FIG. 5. The submaxillary Gland and Duct.
a, Musculus mylo-hyoidæus. b. Hyo-glos-
sus. c, Submaxillary gland extra situ. d, Its
duct.
PLATE

235
Part II. OF THE MUSCLES.
PLATE XXIV.
FIG. 1 The muscles immediately under
the common teguments on the posterior part of
the body, are represented in the right side; and
on the left side the MUSCLES are seen which
come in view when the exterior ones are taken
away.
HEAD.—AA, Occipito-frontalis. B, At-
tollens aurem. C, Part of the orbicularis pal-
pebrarum. D, Masseter. E, Pterygoidæus in-
ternus.
TRUNK.—Right side. FFF, Trapezius seu
cucullaris. GGGG, Latissimus dorsi. H, Part
of the obliquus externus abdominis.
TRUNK.—Left side. I, Splenius. K, Part
of the complexus. L, Levator scapulæ. M,
Rhomboides. NN, Serratus posticus inferior.
O, Part of the longissimus dorsi. P, Part of the
sacro-lumbalis. Q, Part of the semi-spinalis
dorsi. R, Part of the serratus anticus major. S,
Part of the obliquus internus abdominis.
SUPERIOR EXTREMITY.—Right side. T,
Deltoides. U, Triceps extensor cubiti. V, Su-
pinator longus. WW, Extensores carpi radia-
lis longior and brevior. XX, Extensor carpi
ulnaris. YY, Extensor digitorum communis.
Z, Abductor indicis. 123, Extensores pol-
licis.
SUPERIOR EXTREMITY.—Left side. a, Su-
pra spinatus. b, Infra-spinatus. c, Teres mi-
nor.

236 
PART II. OF THE MUSCLES. 
nor. d, Teres major. e, Triceps extensor cu-
biti. ff, Extensores carpi radiales. g, Supi-
nator brevis. h, Indicator. 123, Extensores
pollicis. i, Abductor minimi digiti. k, Inter-
ossei.
INFERIOR EXTREMITY.—Right side. l,
Glutæus maximus. m, Part of the Glutæus
medius. n, Tensor vaginæ femoris. o, Graci-
lis. p p, Abductor femoris magnus. q, Part
of the vastus internus. r, Semimembranosus.
s, Semitendinosus. t, Long head of the biceps
flexor cruris. u u, Gastrocnemius externus seu
gemellus. v, Tendo Achiilis. w, Solens seu
gastrocnemius interims. xx, Peronæus longus
and brevis. y, Tendons of the flexor longus digi-
torum pedis;—and under them * flexor brevis di-
gitorum pedis. z, Abductor minimi digiti pedis.
INFERIOR EXTREMITY. Left side. m, n,
o, p, q, r, s, t, v, ww, xx, y, z, Point the same 
parts as in the right side. a, Pyriformis. bb,
Gemini. cc, Obturator internus. d, Quadra-
tus femoris. e, Coccygaæus. f, The short head
of the biceps flexor cruris. gg, Plantaris. b,
Poplitæus. i, Flexor longus pollicis pedis.
FIG. 2. The Palm of the Left Hand after the
common Teguments are removed, to show
the MUSCLES of the Fingers.
a, Tendon of the flexor carpi radialis. b,
Tendon of the flexor carpi ulnaris. c, Tendons
of the flexor sublimis perforatus, profundus per-
forans 



 

 

 

237
PART II. OF THE MUSCLES.
forans and lumbricales. d, Abductor pollicis.
e e, Flexor pollicis longus. f, Flexor pollicis
brevis. g, Palmaris brevis. h, Abductor mi-
nimi digiti. i, Ligamentum carpi annulare, k,
A probe put under the tendons of the flexor di-
gitorum sublimis; which are perforated by l, the
flexor digitorum profundus, mmmm, Lum-
bricales. n, Abductor pollicis.
FIG. 3. A Fore-view of the foot and Tendons of
the Flexores Digitorum.
a, Cut extremity of the tendo Achillis. b,
Upper part of the astragalus. c, Os calcis. d,
Tendon of the tibialis anticus. e, Tendon of
the extensor pollicis longus. f, Tendon of the
peronæus brevis. g, Tendons of the flexor di-
gitorum longus, with the nonus Vesalii. h h,
The whole of the flexor digitorum brevis.
FIG. 4. Muscles of the Anus.
a a, An out line of the buttocks, and upper
part of the thighs. b, The testes contained in
the scrotum. cc, Sphincter ani. d, Anus, e,
Levator ani. ff, Erector penis. gg, Accele-
rator urinæ. h, Corpus cavernosum urethræ.
FIG. 5. Muscles of the Penis.
aa, b, d, ee, ff, h, point the same as in fig.
4. c, Sphincter ani. gg, Transversalis penis.
PART 

238 
PART III. OF THE ABDOMEN. 
PART III.
OF THE ABDOMEN, OR LOWER BELLY.
THE abdomen, or lower belly, extends from
the lower extremity of the sternum, or the
hollow, usually called the pit of the stomach,
and more properly scrobiculus cordis, to the low-
er part of the trunk.
It is distinguished into three divisions called
regions; of these the upper one, which is called
the epigastric region, begins immediately under
the sternum, and extends to within two fingers
breadth of the navel, where the middle or um-
bilical region begins, and reaches to the same dis-
tance below the navel. The third, which is
called the hypogastric, includes the rest of the
abdomen, as far as the os pubis.
Each of these regions is subdivided into three
others; two of which compose the sides, and
the other the middle part of each region.
The middle part of the upper region is called
epigastrium, and its two sides hypochondria. The
middle part of the next region is the umbilical
region, properly so called, and its two sides are
the flanks, or iliac regions. Lastly, the middle
part of the lower region retains the name of hy-
pogastrium, and its sides are called inguina or
groins. The back part of the abdomen bears
the name of lumbar region.
These

239
PART III. OF THE ABDOMEN.
These are the divisions of the lower belly,
which are necessary to be held in remembrance,
as they frequently occur in surgical and anato-
mical writing. We will now proceed to exa-
mine the contents of the abdomen; and after
having pointed out the names and arrangement
of the several viscera contained in it, describe
each of them separately.
After having removed the skin, adipose mem-
brane, and abdominal muscles, we discover the
peritonæum or membrane that envelopes all the
viscera of the lower belly. This being opened,
the first part that presents itself is the omentum
or cawl, floating on the surface of the intestines,
which are likewise seen every where loose and
moist, and making a great number of circum-
volutions through the whole cavity of the abdo-
men. The stomach is placed in the epigastrium,
and under the stomach is the pancreas. The
liver fills the right hypochondrium, and the
spleen is situated in the left. The kidneys are
seen about the middle of the lumbar region, and
the urinary bladder and parts of generation are
are seated in the lower division of the belly.
SECT. 1. Of the Peritonæum.
The peritonæum is a strong simple mem-
brane, by which all the viscera of the abdomen
are surrounded, and in some measure supported.
Many anatomical writers, particularly Winslow,
have 

240 
PART III. OF THE ABDOMEN. 
have described it as being composed of two dis-
tinct membranous laminæ; but their description
seems to be erroneous. What perhaps appeared
to be a second lamina, being found to be simply
a cellular coat, which fends off productions to
the blood-vessels passing out of the abdominal
cavity. The aorta and vena cava likewise de-
rive a covering from the same membrane, which
seems to be a part of the cellular membrane we
have already described.
The peritonæum, by its productions and re-
duplications, envelopes the greatest part of the
abdominal viscera. It is soft, and capable of
considerable extension; and is kept smooth and
moist by a vapour, which is constantly exhaling
from its inner surface, and is returned again into
the circulation by the absorbents.
This moisture not only contributes to the soft-
ness of the peritonæum, but prevents the attri-
tion, and other ill effects which would other-
wise probably be occasioned, by the motion of
the viscera upon each other.
When this fluid is supplied in too great a
quantity, or the absorbents become incapable of
carrying it off, it accumulates, and constitutes an
ascites or dropsy of the belly; and when by
any means the exhalation is discontinued, the
peritonæum thickens, becomes diseased, and the
viscera are sometimes found adhering to each
other.
The peritonæum is not a very vascular mem-
3 brane,


241
PART III. OF THE ABDOMEN.
brane. In a sound state it seems to be endued
with little or no feeling, and the nerves that
pass through it appear to belong to the abdomi-
nal muscles.
SECT. II. Of the Omentum.
The omentum, epiploon, or cawl, is a dou-
ble membrane, produced from the peritonæum.
It is interlarded with fat, and adheres to the sto-
mach, spleen, duodenum, and colon; from thence
hanging down loose and floating on the surface
of the intestines. Its size is different in different
subjects. In some it descends as low as the pel-
vis, and it is commonly longer at the left side
than the right.
This part, the situation of which we have just
now described, was the only one known to the
ancients under the name of epiploon; but at pre-
sent we distinguish three omenta, viz. omentum
magnum colico gastricum, omentum parvum hepa-
tico gastricum, and omentum colicum. They all
agree in being formed of two very delicate la-
minæ, separated by a thin layer of cellular mem-
brane.
The omentum magnum colico gastricum, of
which we have already spoken, derives its ar-
teries from the splenetic and hepatic. Its veins
terminate in the vena portæ. Its nerves, which
are very few, come from the splenetic and he-
patic plexus.
Q The


242 
PART III. OF THE ABDOMEN. 
The omentum parvum hepatico gastricum,
abounds less with fat than the great epiploon. It
begins at the upper part of the duodenum, ex-
tends along the lesser curvature of the stomach
as far as the œsophagus, and terminates about
the neck of the gall-bladder, and behind the
left ligament of the liver, so that it covers the
lesser lobe; near the beginning of which we may
observe a small opening, first described by Win-
slow, through which the whole pouch may ea-
sily be distended with air (X). The vessels of
the omentum parvum are derived chiefly from
the coronary stomachic arteries and veins.
The omentum olicum begins at the fore part
of the cœcum and right side of the colon. It ap-
pears as a hollow conical appendage to these
intestines, and usually terminates at the back
of the omentum magnum. It seems to be no-
thing more than a membranous coat of the
cœcum and colon, assuming a conical shape with
air.
The uses of the omentum are not yet satisfac-
torily determined. Perhaps by its softness and
looseness it may serve to prevent those adhesions
of the abdominal viscera, which have been found
to take place when the fat of the omentum has
been much wasted. Some authors have sup-
posed
(X) This membranous bag, though exceedingly thin and
transparent, is found capable of supporting mercury, thrown
into it by the same channel.

243
PART III. OF THE ABDOMEN.
posed, that it assists in the preparation of bile;
but this idea is founded merely on conjecture.
SECT. III. Of the Stomach.
The stomach is a membranous and muscular
bag, in shape not unlike a bagpipe, lying across
the upper part of the abdomen, and inclining ra-
ther more to the left than the right side.
It has two orifices, one of which receives the
end of the œsophagus, and is called the cardia,
and sometimes the left and upper orifice of the
stomach; though its situation is not much higher
than the other, which is styled the right and in-
ferior orifice, and more commonly the pylorus:
both these openings are more elevated than the
body of the stomach.
The aliment passes down the œsophagus into
the stomach through the cardia, and after hav-
ing undergone the necessary digestion, passes
out at the pylorus where the intestinal canal
commences.
The stomach is composed of four tunics or
coats, which are so intimately connected toge-
ther that it requires no little dexterity in the ana-
tomist to demonstrate them. The exterior one
is membranous, being derived from the perito-
næum.—The second is a muscular tunic, com-
posed of fleshy fibres which are in the greatest
number about the two orifices.—The third is
called the nervous coat, and within this is the
Q2 villous 


244 
OF THE ABDOMEN.
villous or velvet-like coat which composes the
inside of the stomach.
The two last coats being more extensive than
the two first, form the folds, which are observ-
ed every where in the cavity of this viscus, and
more particularly about the pylorus; where they
seem to impede the too hasty exclusion of the
aliment, making a considerable plait, called val-
vula pylori.
The inner coat is constantly moistened by a
mucus, which approaches to the nature of the
saliva, and is called the gastric juice; this liquor
has been supposed to be secreted by certain mi-
nute glands (Y) seated in the nervous tunic, whose
excretory ducts open to the surface of the villous
coat.
The arteries of the stomach called the gas-
tric arteries are principally derived from the cæ-
liac; some of its veins pass to the splentic, and
others to the vena portæ; and its nerves are
chiefly from the eight pair or par vagum.
The account given of the tunics of the sto-
mach may be applied to the whole alimentary
canal;
(Y) Heister, speaking of these glands, very properly says,
"in porcis facile, in homine raro observantur;" for although
many anatomical writers have described their appearance
and figure, yet they do not seem to have been hitherto sa-
tisfactorily demonstrated in the human stomach; and the
gastric juice is now more generally believed to be derived
from the exhalent arteries of the stomach. 

145
PART III. OF THE ABDOMEN.
canal; for both the œsophagus and intestines
are, like this viscus, composed of four coats.
Before we describe the course of the aliment
and the uses of the stomach, it will be necessary
to speak of other parts which assist in the pro-
cess of digestion.
SECT. IV. Of the Oesophagus.
The œsophagus or gullet is a membranous
and muscular canal, extending from the bottom
of the mouth to the upper orifice of the stomach.
—Its upper part where the aliment is received is
shaped somewhat like a funnel, and is called the
pharynx.
From hence it runs down close to the bodies
of the vertebræ as far as the diaphragm, in which
there is an opening through which it passes, and
then terminates in the stomach about the ele-
venth or twelfth vertebra of the back.
The œsophagus is plentifully supplied with
arteries from the external carotid, bronchial, and
superior intercostal arteries; its veins empty
themselves into the vena azygos, internal jugu-
lar, and mammary veins, &c.
Its nerves are derived chiefly from the eighth
pair.
We likewise meet with a mucus in the œsopha-
gus, which every where lubricates its inner surface,
and tends to assist in deglutition.—This mucus
seems to be secreted by very minute glands, like
the

246 
PART III. OF THE ABDOMFN. 
the mucus in other parts of the alimentary ca-
nal.
SECT. V. Of the Intestines.
THE intestines form a canal, which is usually
six times longer than the body to which it be-
longs. This canal extends from the pylorus, or
inferior orifice of the stomach, to the anus.
It will be easily understood, that a part of such
great length must necessarily make many circum-
volutions, to be confined with so many other
viscera within the cavity of the lower belly.
Although the intestines are in fact, as we have
observed, only one long and extensive canal, yet
different parts have been distinguished by diffe-
rent names.
The intestines are first distinguished into two
parts, one of which begins at the stomach, and
is called the thin or small intestines, from the
small size of the canal, when compared with the
other part, which is called the large intestines,
and includes the lower portion of the canal down
to the anus.
Each of these parts has it its subdivisions.—
The small intestines being distinguished into
duodenum, jejunum, and ilium, and the
larger portion into cœcum, colon, and rec-
tum.
The small intestines fill the middle and fore
parts of the belly, while the large intestines fill
the 

247
PART III. OF THE ABDOMEN.
the sides and both the upper and lower parts of
the cavity.
The duodenum, which is the first of the
small intestines, is so called, because it is about
12 inches long. It begins at the pylorus and
terminates in the jejunum, which is a part of
the canal observed to be usually more empty than
the other intestines.—This appearance gives it
its name, and likewise serves to point out where
it begins.
The next division is the ilium, which of it-
self exceeds the united length of the duodenum
and jejunum, and has received its name from its
numerous circumvolutions. The large circum-
volution of the ilium covers the first of the large
intestines called the cœcum (X) which seems pro-
perly to belong to the colon, being a kind of
pouch of about four fingers in width, and near-
ly of the same length, having anteriorly a lit-
tle appendix, called appendix cœci.
The cœcum is placed in the cavity of the os
ilium on the right side, and terminates in the
colon, which is the largest of all the intestines.
This intestine ascends by the right kidney to
which it is attached, passes under the hollow
part
(X) Anatomists have differed with respect to this division
of the intestines.—The method here followed is now gene-
rally adopted; but there are authors who allow the name
of cœcum only to the little appendix, which has likewise
been called the vermiform appendix, from its resemblance to
a worm in size and length. 

248 
PART III. OF THE ABDOMEN. 
part of the liver, and the bottom of the stomach,
to the spleen, to which it is likewise secured, as
it is also to the left kidney; and from thence
passes down towards the os sacrum, where, from
its straight course, the canal begins to take the
name of rectum. 
There are three ligamentous bands extending
through the whole length of the colon, which,
by being shorter than its two inner coats, serve
to increase the plaits on the inner surface of this
gut.
The anus which terminates the intestinum
rectum, is furnished with three muscles; one of
these is composed of circular fibres, and from its
use in shutting the passage of the anus is called
sphincter ani.
The other two are the levatores ani, so called,
because they elevate the anus after dejection.
When these by palsy, or any other disease, lose
the power of contracting, the anus prolapses;
and when the sphincter is affected by similar causes,
the fæces are voided involuntarily.
It has been already observed, that the intestinal
canal is composed of four tunics; but it remains
to be remarked, that here, as in the stomach,
the two inner tunics being more extensive than
the other two, form the plaits which are to be
seen in the inner surface of the intestines, and
are called valvulæ conniventes.
Some authors have considered these plaits as
tending to retard the motion of the fæces, in
order 

249
PART III. OF THE ABDOMEN.
order to afford more time for the separation of the
chyle; but there are others who attribute to them
a different use: they contend, that these valves,
by being naturally inclined downwards, can-
not impede the descent of the fæces, but that
they are intended to prevent their return up-
wards.
They are probably destined for both these uses;
for although these folds incline to their lower
side, yet the inequalities they occasion in the ca-
nal are sufficient to retard, in some measure, the
progressive motion of the fæces, and to afford a
greater surface of the absorption of chyle, and
their natural position seems to oppose itself to the
return of the aliment.
Besides these valvulæ conniventes, there is one
more considerable than the rest, called the valve
of the colon; which is found at that part of the
canal where the intestinum ilium is joined to
the colon. This valve permits the alimentary
pulp to pass downwards, but serves to prevent
its return upwards; and it is by this valve, that
glysters are prevented from passing into the small
intestines (Y).
Of the little vermiform appendix of the cœ-
cum, it will be sufficient to say, that its uses have
never
(Y) This is not invariably the case, for the contents of a
glyster have been found not only to reach the small intes-
tines, but to be voided at the mouth. Such instances, how-
ever, are not common.

250 
PART III. OF THE ABDOMEN. 
never yet been ascertained. In birds we meet
with two of these appendices.
The intestines are lubricated by a constant
supply of mucus, which is probably secreted by
very minute folicles (Z). This mucus promotes
the descent of the alimentary pulp, and in some
measure defends the inner surface of the intes-
tines from the irritation to which it would, per-
haps, otherwise be continually exposed from the
aliment; and which, when in a certain degree,
excites a painful disorder called colic, a name
given to the disease, because its most usual seat
is in the intestinum colon.
The intestines are likewise frequently distend-
ed with air, and this distention sometimes occa-
sions pain, and constitutes the flatulent colic.
The arteries of the intestines are continuati-
ons of the mesenteric arteries, which are deriv-
ed in two considerable branches from the aorta.
—The redundant blood is carried back into the
vena portarum.
In
(Z) Some writers have distinguished these glands into mi-
liary, lenticular, &c.—Brunner and Peyer were the first ana-
tomists who described the glands of the intestines, and their
descriptions were chiefly taken from animals, these glandular
appearances not seeming to have been hitherto satisfactorily
pointed out in the human subject.—It is now pretty general-
ly believed, that the mucus which every where lubricates
the alimentary canal, is exhaled from the minute ends of ar-
teries, and that these extremities first open into a hollow ve-
sicle, from whence the deposited juice of several branches
flows out through one common orifice. 

251
PART III. OF THE ABDOMEN.
In the rectum the veins are called hemorrhoi-
dal, and are there distinguished into internal and
external; the first are branches of the inferior
mesenteric vein, but the latter pass into other
veins. Sometimes these veins are distended with
blood from obstructions, from weakness of their
coats, or from other causes, and what we call
the hæmorrhoids takes place. In this disease they
are sometimes ruptured; and the discharge of
blood which consequently follows, has probably
occasioned them to be called hæmorrhoidal veins.
The nerves of the intestines are derived from
the eight pair.
SECT. VI. Of the Mesentery.
The name of the mesentery implies the situa-
tion amidst the intestines. It is in fact a part of
the peritonæum, being a reduplication (A) of that
membrane
(A) He who only reads of the reduplication of mem-
branes, will perhaps not easily understand how the perito-
næum and pleura are reflected, over the viscera in their several
cavities; for one of these serves the same purposes in the tho-
rax that the other does in the abdomen. This disposition,
for the discovery of which we are indebted to modern anato-
mists, constitutes a curious part of anatomical knowledge:
but the student, unaided by experience, and assisted only by
what the limits of this work would permit us to say on the
occasion, would probably imbibe only confused ideas of the
matter; and it will perfectly answer the present purpose, if
he considers the mesentery as a membrane attached by one
of its sides to the lumbar vertebræ, and by the other to the
intestines.

252 
PART III. OF THE ABDOMEN. 
membrane from each side of the lumbar verte-
bræ, to which it is firmly attached, so that it is
formed of two laminæ, connected to each other
by cellular membrane.
The intestines, in their different circumvolu-
tions, form a great number of arches, and the
mesentry accompanies them through all these
turns; but by being attached only to the hollow
part of each arch; it is found to have only a
third of the extent of the intestines.
That part of this membrane which accompa-
nies the small intestines is the mesentery, properly
so called; but those parts of it which are attach-
ed to the colon and rectum are distinguished by
the names of meso-colon and meso-rectum.
There are many conglobate glands dispersed
through this double membrane, through which
the lacteals and lymphatics pass in their way to
the thoracic duct. The blood-vessels of the
mesentery were described in speaking of the in-
testines.
This membrane, by its attachment to the
vertebræ, serves to keep the intestines in their na-
tural situation. The idea usually formed of the
colic called miserere, is perfectly erroneous; it
being impossible that the intestines can be twisted,
as many suppose they are, in that disease, their
attachment to the mesentery effectually prevent-
ing such an accident—but a disarrangement
sometimes takes place in the intestinal canal it-
self, which is productive of disagreeable and
some-

253
PART III. OF THE ABDOMEN.
sometimes fatal consequences.—This is by an in-
trosusception of the intestine, an idea of which
may be easily formed, by taking the finger of
a glove, and involving one part of it within the
other.
If inflammation takes place, the stricture in
this case is increased, and the peristaltic motion
of the intestines (by which is meant the pro-
gressive motion of the fæces downwards) is in-
verted, and what is called the iliac passion takes
place. The same effect may be occasioned by
a descent of the intestine, or of the omentum
either with it or by itself, and thus constituting
what is called an hernia or rupture; a term by
which in general is meant the falling down or
protrusion of any part of the intestine or omen-
tum, which ought naturally to be contained with-
in the cavity of the belly.
To convey an idea of the manner in which
such a descent takes place, it will be necessary to
observe, that the lower edge of the tendon of
of the musculus obliquus externus, is stretched
from the fore-part of the os ilium or haunch-
bone of the os pubis, and constitutes what is
called Poupart's or Fallopius's ligament, forming
an opening, through which pass the great crural
artery and vein. Near the os pubis the same
tendinous fibres are separated from each other,
and form an opening on each side, called the
abdominal ring, through which the spermatic
vessels pass in men, and the ligamenta uteri in
women.

254 
PART III. OF THE ABDOMEN. 
women. In consequence of violent efforts, or
perhaps of natural causes, the intestines are found
sometimes to pass through these openings: but
the peritonæum which incloses them when in
their natural cavity, still continues to surround
them even in their natural cavity, still continues
to surround them even in their descent. This
membrane does not become torn or lacerated by
the violence, as might be easily imagined; but
its dilatibility enables it to pass out with the vis-
cus, which it incloses as it were in a bag, and
thus forms what is called the hernial sac.
If the hernia be under Poupart's ligament,
it is called femoral; if in the groin, inguinal (B),
and scrotal, if in the scrotum. Different names
are likewise given to the hernia as the contents
of the sac differ, whether of omentum only or
intestine, or both;—but these definitions more
properly belong to the province of surgery.
SECT. VII Of the Pancreas.
THE pancreas is a conglomerate gland placed
behind the bottom of the stomach, towards the
first vertebra of the loins; shaped like a dog's
tongue with its point stretched out towards the
spleen, and its other end extending towards the
duodenum. It is about eight fingers breadth in
length,
(B) The hernia congenita will be considered with the male
organs of generation, with which it is intimately connected.

255
PART III. OF THE ABDOMEN.
length, two or three in width, and one in thick-
ness.
This viscus, which is of a yellowish colour,
somewhat inclined to red, is covered with a mem-
brane which it derives from the peritonæum.
Its arteries, which are rather numerous than
large, are derived chiefly from the splenic and
hepatic, and its veins pass into the veins of the
same name.—Its nerves are derived from the in-
tercostal.
The many little glands of which it has been
observed the pancreas is composed, all serve to
secrete a liquor called the pancreatic juice, which
in its colour, consistence, and other properties,
does not seem to differ from the saliva. Each of
these glands sends out a little excretory duct,
which, uniting with others, help to form larger
ducts; and all these at last terminate in one com-
mon excretory duct (first discovered by Virtsun-
gus in 1642), which runs through the middle
of the gland, and is now usually called ductus
pancreaticus Virtsungi. This canal opens into the
intestinum duodenum, sometimes by the same
orifice with the biliary duct, and sometimes by
a distinct opening. The liquor it discharges be-
ing of a mild and insipid nature, serves to dilute
the alimentary pulp, and to incorporate it more
easily with the bile.
SECT. 

256 
PART III. OF THE ABDOMEN. 
SECT. VIII. Of the Liver.
The liver is a viscus of considerable size, and
of a reddish colour; convex superiority and an-
teriorly where it is placed under the ribs and di-
aphragm, and of an unequal surface posteriorly.
It is chiefly situated in the right hypochondrium,
and under the false ribs; but it likewise extends
into the epigastric region, where it borders upon
the stomach. It is covered by a production of
the peritonæum, which serves to attach it by
three of its reduplications to the false ribs. These
reduplications are called ligaments, though very
different in their texture from what are called by
the same name in other parts of the body. The
umbilical cord, too, which in the fœtus is per-
vious, gradually becomes a simple ligament after
birth; and, by passing to the liver, serves like-
wise to secure it in its situation.
At the posterior part of this organ where the
umbilical vessels enter, it is found divided into
two lobes. Of these, the largest is placed in the
right hypochondrium; the other, which covers
part of the stomach, is called the little lobe. All
the vessels which go to the liver pass in at the
fissure we have mentioned; and the production
of the peritonæum, which invests the liver, was
described by Glisson, an English anatomist, as
accompanying them in their passage, and sur-
rounding them like a glove; hence this produc-
2 tion


257
PART III. OF THE ABDOMEN.
tion has been commonly known by the name of
capsula of Glisson: but it appears to be chiefly a
continuation of the cellular membrane which co-
vers the vena porta ventralis.
The liver was considered by the ancients as
an organ destined to prepare and perfect the
blood; but later discoveries have proved, that
this opinion was wrong, and that the liver is a
glandular substance formed for the secretion of
the bile.
The blood is conveyed to the liver by the he-
patic artery and the vena porta. This is contra-
ry to the mode of circulation in other parts,
where veins only serve to carry off the redundant
blood: but in this viscus the hepatic artery,
which is derived from the cæliac, is principally
destined for its nourishment; and the vena por-
ta, which is formed by the union of the veins
from most of the abdominal viscera, furnishes the
blood from which the bile is chiefly to be separat-
ed; so that these two series of vessels serve very
distinct purposes. The vena porta, as it is rami-
fied through the liver, performs the office both
of a vein and an artery; for like the former it
returns the blood from the extremities of arte-
ries, while as the latter it prepares it for secre-
tion.
The nerves of the liver are branches of the
intercostal and par vagum. The bile, after be-
ing separated from the mass of blood, in a man-
ner of which mention will be made in another
R place


258 
PART III. OF THE ABDOMEN. 
place, is conveyed out of this organ by very mi-
nute excretory ducts, called poribiliarii; these
uniting together like the excretory ducts in the
pancreas, gradually form larger ones, which at
length terminate in a considerable canal called
ductus hepaticus.
SECT. IX. Of the Gall-bladder.
The gall-bladder is a little membranous bag,
shaped like a pear, and attached to the posterior
and almost inferior part of the great lobe of the
liver.
It has two tunics; of which the exterior one
is a production of the peritonæum. The inte-
rior, or villous coat, is supplied with a mucus
that defends it from the acrimony of the bile.
These two coverings are intimately connected by
means of cellular membrane, which from its firm
glistening appearance has generally been spoken
of as a muscular tunic.
The gall-bladder is supplied with blood-vessels
from the hepatic arteries. These branches are
called the cystic arteries, and the cystic veins car-
ry back the blood.
Its nerves are derived from the same origin as
those of the liver.
The neck of the gall-bladder is continued in
the form of a canal called ductus cysticus, which
soon unites with the ductus hepaticus we describ-
ed as the excretory duct of the liver; and form-
ing 

259
PART III. OF THE ABDOMEN.
ing one common canal, takes the name of ductus
choledochus communis, through which both the
cystic and hepatic bile are discharged into the du-
odenum. This canal opens into the intestine in
an oblique direction, first passing through the
exterior tunic, and then piercing the other coats
after running between each of them a very little
way. This œconomy serves two useful pur-
poses;—to promote the discharge of bile and to
prevent its return.
The bile may be defined to be a natural liquid
soap, somewhat unctuous and bitter, and of a
yellowish colour, which easily mixes with water,
oil, and vinous spirits, and is capable of dissolv-
ing resinous substances. From some late experi-
ments made by M. Cadet*, it appears to be
formed of an animal oil, combined with the al-
kaline base of sea-salt, a salt of the nature of
milk, and a calcareous earth which is slightly fer-
ruginous.
Its definition seems sufficiently to point out
the uses for which it is intended (C). It blends
the alimentary mass, by dividing and attenuating
it; corrects the too great disposition to acescency,
which the aliment acquires in the stomach; and,
finally, by its acrimony, tends to excite the pe-
ristaltic motion of the intestines.
R2 After
* Mem. de l' Acad. des Sciences. 1767.
(C) The ancients, who were not acquainted with the real
use of the liver, considered the bile as an excrementitious
and useless fluid.

260 
PART III. OF THE ABDOMEN. 
After what has been said, it will be conceived
that there are two sorts of bile; one of which
is derived immediately from the liver through the
hepatic duct, and the other from the gall-blad-
der. These two biles, however, do not essenti-
ally differ from each other. The hepatic bile in-
deed is milder, and more liquid than the cystic,
which is constantly thicker and yellower; and
by being bitterer, seems to possess greater activity
than the other.
Every body knows the source of the hepatic
bile, that it is secreted from the mass of blood
by the liver; but the origin of the cystic bile has
occasioned no little controversy amongst anato-
mical writers. There are some who contend,
that it is separated in the substance of the liver,
from whence it passes into the gall-bladder
through particular vessels. In deer, and in some
other quadrupeds, as well as in several birds and
fishes, there is an evident communication, by
means of particular vessels, between the liver
and the gall-bladder. Bianchi, Winslow, and
others, have asserted the existence of such vessels
in the human subject, and named them hepati-
cystic ducts; but it is certain that no such ducts
exist.—In obstructions of the cystic duct, the
gall-bladder has been found shrivelled and emp-
ty: so that we may consider the gall-bladder as
a reservoir of hepatic bile; and that it is an es-
tablished fact, that the whole of the bile con-
tained in the gall-bladder is derived from the li-
ver;

261
PART III. OF THE ABDOMEN.
ver; that it passes from the hepatic to the cystic
dud, and from that to the gall-bladder. The
difference in the colour, consistence, and taste of
the bile, is merely the consequence of stagnation
and absorption. When the stomach is distend-
ed with aliment, this reservoir undergoes a cer-
tain degree of compression, and the bile passes
out into the intestinal canal; and in the efforts to
vomit, the gall-bladder seems to be constantly af-
fected, and at such times discharges itself of its
contents.
Sometimes the bile concretes in the gall-blad-
der, so as to form what are called gall-stones (D).
When these concretions pass into the cystic duct,
they sometimes occasion exquisite pain, by dis-
tending the canal in their way to the duodenum;
and by lodging in the ductus choledochus com-
munis, and obstructing the course of the bile,
this fluid will be absorbed, and by being carried
back into the circulation occasion a temporary
jaundice.
SECT. X. Of the Spleen.
The spleen is a soft and spongy viscus, of a
bluish
(D) These concretions sometimes remain in the gall-blad-
der without causing any uneasiness. Dr. Heberden relates,
that a gall-stone weighing two drams was found in the gall-
bladder of the late Lord Bath, though he had never com-
plained of the jaundice, nor of any disorder which he could
attribute to that cause. Med. Trans. Vol. ii.

262 
PART III. OF THE ABDOMEN. 
bluish colour, and about five or six fingers
breadth in length, and three in width, situ-
ated in the left hypochondrium, between the
stomach and the false ribs. That side of it which
is placed on the side of the ribs is convex; and
the other, which is turned toward the stomach,
is concave.
The splenic artery, which is a branch from
the cæliac, supplies this viscus with blood, and
a vein of the same name carries it back into the
vena porta.
Its nerves are derived from a particular plexus
called the splenic, which is formed by branches
of the intercostal nerve, and by the eight pair,
or par vagum.
The ancients, who supposed two sorts of bile,
considered the spleen as the receptacle of what
they called atra bilis. Havers, who wrote pro-
fessedly on the bones, determined its use to be
that of secreting the synovia; and the late Mr.
Hewson imagined, that it concurred with the
thymus and lymphatic glands of the body in
forming the red globules of the blood. All these
opinions seem to be equally fanciful. The want
of an excretory duct has occasioned the real use
of this viscus to be still doubtful. Perhaps the
blood undergoes some change in it, which may
assist in the preparation of the bile. This is the
opinion of the generality of modern physiolo-
gists; and the great quantity of blood with
which it is supplied, together with the course of
its 

263
PART III. OF THE ABDOMEN.
its veins into the vena portæ, seem to render this
notion probable.
SECT. XI Of the Glandulæ Renales, Kidneys,
and Ureters.
The glandulæ renales, which were by the
ancients supposed to secrete the atra bilis, and by
them named capsulæ atrabilares, are two flat bo-
dies of an irregular figure, one on each side be-
tween the kidney and the aorta.
In the fœtus they are as large as the kidneys:
but they do not increase afterwards in proportion
to those parts; and in adults and old people they
are generally found shrivelled, and much wasted,
They have their arteries and veins. Their ar-
teries usually arise from the splenic or the emul-
gent, and sometimes from the aorta; and their
veins go to the neighbouring veins, or to the
vena cava. Their nerves are branches of the
intercostal.
The use of these parts is not yet perfectly
known. In the fetus the secretion of urine must
be in a very small quantity, and a part of the
blood may perhaps then pass through these chan-
nels, which in the adult is carried to the kidneys
to supply the matter of urine.
The kidneys are two in number, situated one
on the right and the other on the left side in the
lumbar region, between the last false rib and the
os ilium, by the sides of the vertebræ. Each
kidney 

264 
PART III. OF THE ABDOMEN. 
kidney in its figure resembles a sort of bean,
which from its shape is called kidney-bean. The
concave part of each kidney is turned towards
the aorta and vena cava ascendens. They are
surrounded by a good deal of fat, and receive
a coat from the peritonæum; and when this is
removed, a very fine membrane is found invest-
ing their substance and the vessels which ramify
through them.
Each kidney has a considerable artery and
vein, which are called the emulgent. The arte-
ry is a branch from the aorta, and the vein passes
into the vena cava. Their nerves, which every
where accompany the blood-vessels, arise from a
considerable plexus, which is derived from the
intercostal.
In each kidney, which in the adult is of a
pretty firm texture, there are three substances to
be distinguished (E). The outer part is glandu-
lar or cortical, beyond this is the vascular or tu-
bular substance, and the inner part is papillary or
membranous.
It is in the cortical part of the kidney that the
secretion is carried on; the urine being here re-
ceived from the minute extremities of the capilla-
ry arteries, is conveyed out of this cortical sub-
stance by an infinite number of very small cylin-
drical canals or excretory vessels, which consti-
tute
(E) The kidneys in the fœtus are distinctly lobulated; but
in the adult they become perfectly firm, smooth, and re-
gular. 

265
PART III. OF THE ABDOMEN.
tute the tubular part. These tubes, as they ap-
proach the inner substance of the kidney, gradu-
ally unite together; and thus forming larger ca-
nals, at length terminate in ten or twelve little
protuberances called papillæ, the orifices of which
may be seen without the assistance of glasses.
Thee papillæ open into a small cavity or refer-
voir called the pelvis of the kidney, and formed
by a distinct membranous bag which embraces
the papillæ. From this pelvis the urine is con-
veyed through a membranous canal which passes
out from the hollow side of the kidney, a little
below the blood vessels, and is called ureter.
The ureters are each about as large as a com-
mon writing-pen. They are somewhat curved
in their course from the kidneys, like the letter
s, and at length terminate in the posterior and
almost inferior part of the bladder, at some dis-
tance from each other. They pass into the blad-
der in the same manner as the ductus choledoc-
dus communis passes into the intestinum duode-
num, not by a direct passage, but by an oblique
course between the two coats; so that the dis-
charge of urine into the bladder is promoted,
whilst its return is prevented. Nor does this
mode of structure prevent the passage of fluids
only from the bladder into the ureters, but like-
wise air:—for air thrown into the bladder in-
flates it, and it continues to be distended if a
ligature is passed round its neck; which seems
to

266 
PART III. OF THE ABDOMEN. 
to prove sufficiently that it cannot pass into the
ureters.
SECT. XII. Of the Urinary Bladder.
The urinary bladder is a membranous and
muscular bag of an oblong roundish shape, situ-
ated in the pelvis, between the os pubis and in-
testinum rectum in men, and between the os pu-
bis and uterus in women. Its upper and widest
part is usually called the bottom, its narrow part
the neck of the bladder; the former only is co-
vered by the peritonæum.
The bladder is formed of three coats, connect-
ed together by means of cellular membrane.
The external or peritonæal, is only a partial one,
covering the upper and back part of the bladder.
The middle, or muscular coat, is composed of
irritable, and of course muscular fibres, which
are most collected around the neck of the blad-
der, but not so as to form a distinct muscle, or
sphincter, as the generality of anatomists have
hitherto supposed.
The inner coat, though much smoother, has
been said to resemble the villous tunic of the in-
intestines, and like that is provided with a mu-
cus, which defends it against the acrimony of
the urine.
It will be easily conceived from what has
been said, that the kidneys are two glandular bo-
dies, through which a saline and excrementitious
fluid 

267
PART III. OF THE ABDOMEN.
fluid called urine is constantly filtering from the
mass of blood.
While only a small quantity of urine is col-
lected in the bladder, it excites no kind of un-
easiness; but when a greater quantity is accu-
mulated, so that the bladder is distended in a cer-
tain degree, it excites in us a certain sensation,
which brings on as it were a voluntary contrac-
tion of the bladder to promote its discharge.—
But this contraction is not effected by the mus-
cular fibres of the bladder alone: for all the ab-
dominal muscles contract in obedience to our
will, and press downwards all the viscera of the
lower belly; and these powers being united, at
length overcome the resistance of the fibres sur-
rounding the neck of the bladder, which dilates
and affords a passage to the urine through the
urethra.
The frequency of this evacuation depends on
the quantity of urine secreted; on the degree of
acrimony it possesses; on the size of the bladder,
and on its degree of sensibility.
The urine varies much in its colour and con-
tents. These varieties depend, on age, sex, climate,
diet, and other circumstances. In infants it is ge-
nerally a clear watery fluid, without smell or
taste. As we advance in life, it acquires more
colour and smell, and becomes more impregnat-
ed with salts. In old people it becomes still more
acrid and fetid.
In

268 
PART III. OF THE ABDOMEN. 
In a healthy state it is nearly of a straw co-
lour.—After being kept for some time, it depo-
sites a tartarous matter, which is found to be
composed chiefly of earth and salt, and soon in-
crusts the sides of the vessel in which it is con-
tained. While this separation is taking place,
appearances like minute fibres or threads of a
whitish colour, may be seen in the middle of the
urine, and an oily scum observed floating on its
surface. So that the most common appearances
of the urine are sufficient to ascertain that it is a
watery substance, impregnated with earthy, sa-
line, and oily particles.
The urine is not always voided of the same
colour and consistence; for these are found to
depend on the proportion of its watery part to
that of its other constituent principles.—Its co-
lour and degree of fluidity seem to depend on
the quantity of saline and inflammable particles
contained in it: so that an increased proportion
of those parts will constantly give the urine a
higher colour, and add to the quantity of sedi-
ment.
The variety in the appearance of the urine,
depends on the nature and quantity of solid and
fluid aliment we take in; and it is likewise occa-
sioned by the different state of the urinary vessels,
by which we mean the channels through which
it is separated from the blood, and conveyed
through the pelvis into the ureters. The causes
of calculous concretions in the urinary passages,
are 

269
PART. III OF THE ABDOMEN.
are to be looked for in the natural constitution of
the body, mode of life, &c. 
It having been observed, that after drinking
any light wine or Spa water, it very soon passed
off by urine, it has been supposed by some, that
the urine is not altogether conveyed to the blad-
der by the ordinary course of circulation, but
that there must certainly exist some other shorter
means of communication, perhaps by certain
vessels between the stomach and the bladder, or
by a retrograde motion in the lymphatics. But
it is certain, that if we open the belly of a dog,
press out the urine from the bladder, pass a liga-
ture round the emulgent arteries, and then sew
up the abdomen, and give him even the most
diuretic liquor to drink, the stomach and other
channels will be distended with it, but not a drop
of urine will be found to have passed into the
bladder; or the same thing happens when a liga-
ture is thrown round the two ureters. This ex-
periment then seems to be a sufficient proof, that
all the urine we evacuate, is conveyed to the
kidneys through the emulgent arteries, in the
manner we have described.—It is true, that wine
and other liquors promote a speedy evacuation of
urine: but the discharge seems to be merely the
effect of the stimulus they occasion; by which the
bladder and urinary parts are solicited to a more co-
pious discharge of the urine, which was before in
the body, and not immediately of that which was
last drank; and this increased discharge, if the
supply 

270 
PART III. OF THE ABDOMEN. 
supply kept up, will continue: nor will this
appear wonderful, if we confider the great capa-
city of the vessels that go to the kidneys; the
constant supply of fresh blood that is essential to
health; and the rapidity with which it is inces-
santly circulated through the heart to all parts of
the body.
SECT. XIII. Of Digestion.
We are now proceeding to speak of digestion,
which seems to be introduced in this place with
propriety, after a description of the abdominal
viscera, the greater part of which contribute to
this function. By digestion is to be understood,
the changes the aliment undergoes for the forma-
tion of chyle:—these changes are effected in the
mouth, stomach, and small intestines.
The mouth, of which every body has a ge-
neral knowledge, is the cavity between the two
jaws, formed anteriorly and laterally by the lips,
teeth; and cheeks, and terminating posteriorly in
the throat.
The lips and cheeks are made up of fat and
muscles, covered by the cuticle, which is conti-
nued over the whole inner surface of the mouth,
like a fine and delicate membrane.—Beside this
membrane, the inside of the mouth is furnished
with a spongy and very vascular substance called
the gums, by means of which the teeth are se-
cured in their sockets. A similar substance covers
the roof of the mouth, and forms what is called
the 

271
PART III. OF THE ABDOMEN.
the velum pendulum palati, which is fixed to the
extremity of the arch formed by the ossa max-
illaria and ossa palati, and terminates in a soft,
small, and conical body, named uvula; which
appears, as it were, suspended from the middle
of the arch over the basis of the tongue.
The velum pendulum palati performs the of-
fice of a valve between the cavity of the mouth
and the pharynx, being moved by several mus-
cles (F).
The tongue is composed of several muscles
(G) which enable it to perform a variety of mo-
tions for the articulation of the voice; for the
purposes of mastication; and for conveying the
aliment into the pharynx. Its upper part is co-
vered with papillæ, which constitute the organ
of taste, and are easily to be distinguished; it is
covered by the same membrane that lines the in-
side of the mouth, and which makes at its infe-
rior part towards its basis a reduplication called
frænum.
Posteriorly, under the veium palati, and at
the basis of the tongue, is the pharynx: which
is the beginning of the œsophagus, stretched out
every way, so as to resemble the top of a fun-
3 nel,
(F) These are the circumflexus palati, levator palati mol-
lis, palato-pharyngæus constrictor isthmi saucium and azygos
uvulæ.
(G) These are, the genio-glossus, hyo-glossus, lingualis,
and stylo-glossus.

272 
PART III. OF THE ABDOMEN. 
nel, through which the aliment passes into the
stomach.
The mouth has a communication with the
nostrils at its posterior and upper part; with the
ears, by the Eustachian tubes; with the lungs,
by means of the larynx; and with the stomach,
by means of the œsophagus.
The pharynx is constantly moistened by a
fluid, secreted by two considerable glands called
the tonsils, one on each side of the velum palati.
These glands, from their supposed resemblance
to almonds, have likewise been called amyg-
dalis.
The mouth is moistened by a considerable
quantity of saliva. This fluid is derived from
the parotid glands; a name which by its ety-
mology points out their situation to be near the
ears. They are two in number, one on each
side under the os malæ: and they are of the con-
glomerate kind; being formed of many smaller
glands, each of which sends out a very small ex-
cretory duct, which unites with the rest, to form
one common channel, that runs over the cheek,
and piercing the buccinator muscle, opens into
the mouth on each side, by an orifice into which
a bristle may be easily introduced.—Besides
these, the maxillary glands, which are placed
near the inner surface of the angle of the lower
jaw on each side; the sublingual glands, which
are situated at the root of the tongue ; the glands
of the palate, which are seated in the velum pa-
lati;

273
PART III. OF THE ABDOMEN.
lati; and those of the cheeks, lips, &c. together
with many other less considerable ones,—pour
the saliva into the mouth through their several
excretory ducts.
The saliva, like all the other humours of the
body, is found to be different in different peo-
ple: but in general, it is a limpid and insipid
fluid, without smell in healthy subjects; and these
properties would seem to prove that it contains
very few saline or inflammable particles.
The uses of the saliva seem to be to moisten
and lubricate the mouth, and to assist in reducing
the aliment into a soft pulp before it is conveyed
into the stomach.
The variety of functions which are constant-
ly performed by the living body, must necessa-
rily occasion a continual waste and dissipation of
its several parts. A great quantity is every day
thrown off by the insensible perspiration and
other discharges; and were not these losses
constantly recruited by a fresh supply of chyle,
the body would soon effect its own disso-
lution. But nature has very wisely favour-
ed us with organs fitted to produce such a sup-
ply; and has at the same time endued us with
the sensations of hunger and thirst, that our at-
tention may not be diverted from the necessary
business of nutrition. The sensation of hunger
is universally known; but it would perhaps be
difficult to describe it perfectly in words. It may,
however, be defined to be a certain uneasy sensation
S in


274 
PART III. OF THE ABDOMEN. 
in the stomach, which induces us to wish for so-
lid food; and which likewise serves to point out
the proper quantity, and time for taking it. In
describing the stomach, mention was made of the
gastric juice, as every where lubricating its inner
coat. This humour mixes itself with the aliment
in the stomach, and helps to prepare it for its pas-
sage into the intestines; but when the stomach is
perfectly empty, this same fluid irritates the coats
of the stomach itself, and produces the sensation
of hunger.
A certain proportion of liquid aliment is
required to assist in the process of digestion,
and to afford that moisture to the body, of which
there is such a constant dissipation.—Thirst in-
duces us to take this necessary supply of drink;
and the seat of this sensation is in the tongue,
fauces, and œsophagus, which from their great
sensibility are required to be kept moist : for
though the fauces are naturally moistened by the
mucus and salival juices; yet the blood, when
deprived of its watery part or rendered acrimo-
nious by any natural causes, never fails particu-
larly to affect these parts, and the whole alimen-
tary canal, and to occasion thirst.—This is the
common effect of fevers and of hard labour, by
both which too much of the watery part of the
blood is dissipated.
Mastication and deglutition. It has been ob-
served, that the aliment undergoes some prepa-
tion in the mouth before it passes into the sto-
mach; 

275
PART III. OF THE ABDOMEN.
mach; and this preparation is the effect of mas-
tication. In treating of the upper and lower
jaws, mention was made of the number and ar-
rangement of the teeth. The upper jaw was
described as being immoveable; but the lower
jaw was spoken of as being capable of eleva-
tion and depression, and of a grinding motion.
The aliment, when first carried into the mouth,
is pressed between the teeth of the two jaws by
a very strong and frequent motion of the lower
jaw; and the tongue and the cheeks assisting in
this process, continue to replace the food be-
tween the teeth till it is perfectly divided, and
reduced to the consistence of pulp. The inci-
sores and canini divide it first into smaller pieces,
but it is between the surfaces of the dentes mo-
lares by the grinding motion of the jaw that the
mastication is completed.
During this process, the salival glands being
gently compressed by the contraction of the mus-
cles that move the lower jaw, pour out their sa-
liva: this helps to divide and break down the
food, which at length becomes a kind of pulp,
and is then carried over the basis of the tongue
into the fauces. But to effect this passage into
the œsophagus, it is necessary that the other
openings which were mentioned as having a
communication with the mouth as well as the
pharynx, should be closed; that none of the ali-
ment, whether solid or liquid, may pass into
them, whilst the pharynx alone is dilated to re-
S2 ceive
 

276 
PART III. OF THE ABDOMEN. 
ceive it:—And such a disposition actually takes
place in a manner we will endeavour to de-
scribe.
The trachea arteria, or windpipe, through
which the air is conveyed to the lungs, is plac-
ed before the œsophagus—in the act of swallow-
ing, therefore, if the larynx (for so the upper
part of the trachea is called) is not closed, the
aliment will pass into it in its way to the œso-
phagus. But this is prevented by a small and
very elastic cartilage, called epiglottis, which is
attached only to the fore-part of the larynx; so
that the food in its passage to the œsophagus presses
down this cartilage, which then covers the glot-
tis or opening of the larynx; and at the same
time the velum palati being capable of some de-
gree of motion, is drawn backwards by its mus-
cles, and closes the openings into the nose and
the Eustachian tubes.—This, however, is not
all. The larynx, which being composed of car-
tilaginous rings, cannot fail in its ordinary state
to compress the membranous canal of the œso-
phagus, is in the act of deglutition carried for-
wards and upwards by muscles destined for that
purpose; and consequently drawing the fore-
part of the pharynx with it, that opening is ful-
ly dilated. When the aliment has reached the
pharynx, its descent is promoted by its own pro-
per weight, and by the muscular fibres of the
œsophagus, which continue to contract from
above downwards, until the aliment has reach-
ed

277
PART III. OF THE ABDOMEN.
ed the stomach. That these fibres have no in-
considerable share in deglutition, any person may
experience, by swallowing with his head down-
wards, when the descent of the aliment cannot
possibly be effected by its weight.
It is necessary that the nostrils and the lungs
should communicate with the mouth, for the
purposes of speech and respiration: but if the
most minute part of our food happens to be in-
troduced into the trachea, it never fails to pro-
duce a violent cough, and sometimes the most
alarming symptoms. This is liable to happen
when we laugh or speak in the act of degluti-
tion: the food is then said to have passed the
wrong way. And indeed this is not improper-
ly expressed: for death would soon follow, if
the quantity of aliment introduced into the
trachea should be sufficient to obstruct the respi-
ration only during a very short time; or if the
irritating particles of food should not be thrown
up again by means of the cough, which in these
cases very seasonably increases in proportion to
the degree of irritation.
If the velum palati did not close the passage to
the nostrils, deglutition would be performed
with difficulty, and perhaps not at all; for the ali-
ment would return through the nose, as is some-
times the case in drinking. Children, from a
deficiency in this velum palati, have been seen
to die a few hours after birth; and they who
from 

278 
PART III. OF THE ABDOMEN. 
from disease or any other causes have not this
part perfect, swallow with difficulty.
The aliment after having been sufficiently di-
vided by the action of the teeth, and attenuated
by the saliva, is received into the stomach, where
it is destined to undergo a more considerable
change.
The properties of the aliment not being much
altered at its first entrance into the stomach, and
before it is thoroughly blended with the gastric
juice, is capable of irritating the inner coat of
the stomach to a certain degree, and occasions a
contraction of its two orifices.—In this mem-
branous bag, surrounded by the abdominal vis-
cera, and with a certain degree of natural heat,
the aliment undergoes a constant agitation by
means of abdominal muscles and of the dia-
phragm, and likewise by a certain contraction or
expansion of the muscular fibres of the stomach
itself. By this motion, every part of the food
is exposed to the action of the gastric juice, which
gradually divides and attenuates it, and prepares
it for its passage into the intestines.
Some observations lately published by Mr.
Hunter in the Philosophical Transactions, tend
to throw considerable light on the principles of
digestion. There are few dead bodies in which
the stomach, at its great end, is not found to be
in some degree digested (H). Animals, or parts
of
(H) The Abbe Spallanzani, who has lately written upon di-
gestion, finds, from a variety of experiments, made upon
quadru-

279
PART III. OF THE ABDOMEN.
of animals, possessed of the living principle,
when taken into the stomach, are not in the
least affected by the action of that viscus; but
the moment they lose the living principle, they
become subject to its digestive powers. This
seems to be the case with the stomach, which is
enabled to resist the action of its juices in the
living body: but when deprived of the living
principle, it is then no longer able to resist the
powers of that menstruum, which it had itself
formed for the digestion of its contents; the pro-
cess of digestion appearing to be continued after
death. This is confirmed by what happens in
the stomachs of fishes: they frequently swal-
low, without mastication, fish which are larger
than the digesting parts of their stomach can
contain;
quadrupeds, birds, and fishes, that digestion goes on for
some time after death, though far less considerable than in
living animals, or at least promotes it in a much greater de-
gree. He found also, that when the stomach was cut out of
the body, it had somewhat of the power of digestion, though
this was trifling when compared with that which took place
when the stomach was left in the body. In not one of the
animals was the great curvature of the stomach dissolved,
or much eroded after death. There was often a little ero-
sion, especially in different fishes; in which, when he had
cleared the stomach of its contents, the internal coat was
wanting. In other animals there was only a slight excoria-
tion; and the injury in all of them was at the inferior part,
or great curvature. The coats of the stomach suffer less af-
ter death than flesh, or part of the stomach of similar animals
put into it: the author assigns as a reason for this, that these
bodies are invested on all sides by the gastric fluid, whereas
it only acts on the internal surface of the stomach.

280 
PART III. OF THE ABDOMEN. 
contain; and in such cases, that part which is
taken into the stomach is more or less dissolved,
while that part which remains in the œso-
phagus is perfectly sound; and here, as well
as in the human body, the digesting part of
the stomach is often reduced to the same
state as the digested part of the food. These
appearances tend to prove, that digestion is not
effected by a mechanical power, by contractions
of the stomach, or by heat; but by a fluid se-
creted in the coats of the stomach, which is
poured into its cavity, and there animalizes the
food, or assimilates it to the nature of the blood.
From some late experiments by M. Sage*, it
appears, that inflammable air has the property
of destroying and dissolving the animal texture:
and as we swallow with the substances which
serve us for food a great quantity of atmosphe-
rical air, M. Sage thinks it possible, that de-
plogisticated, which is its principle, may be con-
verted in the stomach into inflammable air, or
may modify into inflammable air a portion of
the oily substance which is the principle of ali-
ments. In this case, would not the inflammable
air (he asks), by dissolving our food, facilitate
its conversion into chyle?
Be this as it may, the food, after having re-
mained one, two, or three hours in the stomach,
is
* Hist. de l'Academie royale des Sciences, &c. pour 1784.
mem. 15. 

281
PART III. OF THE ABDOMEN.
is converted into a greyish pulp, which is usual-
ly called chymus, a word of Greek etymology,
signifying juice, and some few milky or chylous
particles begin to appear.—But the term of its
residence in this bag is proportioned to the na-
ture of the aliment, and to the state of the sto-
mach and its juices. The thinner and more
perfectly digested parts of the food pass by a lit-
tle at a time into the duodenum, through the py-
lorus, the fibres of which relax to afford it a pas-
sage; and the grosser and less digested particles
remain in the stomach, till they acquire a suffi-
cient fluidity to pass into the intestines, where
the nature of the chymus is perfectly changed.
The bile and pancreatic juice which flow into the
duodenum, and the mucus, which is every
where distilled from the surface of the intestines,
mix themselves with the alimentary pulp; which
they still farther attenuate and dissolve, and in-
to which they seem to infuse new properties.
Two matters very different from each other
in their nature and destination, are the result of
this combination.—One of these, which is com-
posed of the liquid parts of the aliment, and of
some of its more solid particles, extremely di-
vided and mixed with the juices we have de-
scribed, constitutes a very mild, sweet, and
whitish fluid, resembling milk, and distinguish-
ed by the name of chyle. This fluid is absorb-
ed by the lacteal veins, which convey it into
the circulation, where, by being assimilated into
the

282 
PART III. OF THE ABDOMEN. 
the nature of blood, it affords that supply of nu-
trition which the continual waste of the body is
found to require.—The other is the remains of
the alimentary mass deprived of all its nu-
tritious particles, and containing only such parts
as were rejected by the absorbing mouths of the
lacteals. This grosser part, called the fæces,
passes on through the course of the intestines, to
be voided at the anus, as will be explained here-
after; for this process in the œconomy cannot
be well understood till the motion of respiration
has been explained. But the structure of the
intestines is a subject which may be properly
described in this place, and deserves to be at-
tended to.
It has been already observed, that the intesti-
nal canal is five or six times as long as the body,
and that it forms many circumvolutions in the
cavity of the abdomen, which it traverses from
the right to the left, and again from the left to
the right; in one place descending, and in ano-
ther extending itself upwards. It was noticed
likewise, that the inner coat of the intestines, by
being more capacious than their exterior tunics,
formed a multitude of plaits placed at a certain
distance from each other, and called valvulæ con-
niventes. Now this disposition will be found to
afford a farther proof of that divine wisdom, which
the anatomist and physiologist cannot fail to dis-
cover in all their pursuits.—For if the intesti-
nal canal was much shorter than it naturally is;
if instead of the present circumvolutions it pass- 
ed

283
PART III. OF THE ABDOMEN.
ed in a direct course from the stomach; and if
its inner surface was smooth and destitute of
valves; the aliment would consequently pass
with great rapidity to the anus, and sufficient
time would be wanting to assimilate the chyle,
and for the necessary absorption of it into the
lacteals: so that the body would be deprived of
the supply of nutrition, which is so essential to
life and health; but the length and circumvo-
lutions of the intestines, the inequality of their
internal surface, and the course of the aliment
through them, all concur to perfect the separa-
tion of the chyle from the fæces, and to afford
the necessary nourishment to the body.
SECT. XIV. Of the Course of the Chyle, and of
the Lymphatic System.
An infinite number of very minute vessels,
called the lacteal veins, arise like net-work from
the inner surface of the intestines, (but princi-
pally from the jejunum and ilium), which are
distended to imbibe the nutritious fluid or chyle.
These vessels, which were discovered by Asel-
lius in 1622 (I), pass obliquely through the
coats
(I) We are informed by Galen, that the lacteals had been
seen in kids by Erasistratus, who considered them as arteries
carrying a milky fluid: but from the remote time in which
he lived, they do not seem to have been noticed till they were
discovered in a living dog by Asellius, who denominated them
lacteals, and considered them as serving to convey the chyle
from the intestines to the liver; for before the discovery of
the thoracic duct, the use of the liver was universally sup-
posed 

284 
PART III. OF THE ABCOMEN. 
coats of the intestine, and running along the
mesentery, unite as they advance, and form
larger branches, all of which pals through the
mesenteric or conglobate glands, which are very
numerous in the human subject. As they run
between the intestines and these glands, they
are styled venæ lacteæ primis generis: but after
leaving these glands, they are found to be less
numerous, and being increased in size, are then
called vene lacteæ secundi generis, which go to
deposit their contents in the thoracic duct, through
which the chyle is conveyed into the blood.
This thoracic duct begins about the lower part
of the first vertebra lumborum, from whence it
passes up by the side of the aorta, between that
and the vena azygos, close to the vertebræ, be-
ing covered by the pleura. Sometimes it is found
divided into branches; but they usually unite
again into one canal, which opens into the left
subclavian vein, after having run a little way in
an oblique course between its coats. The sub-
clavian vein communicates with the vena cava,
which passes to the right auricle of the heart.
The
posed to be that of converting the chyle into blood. But the
discovery of the thoracic duct by Pecquet, not long after,
corrected this error. Pecquet very candidly confesses that
this discovery accidentally arose from his observing a
white fluid, mixed with the blood, flowing out of the
vena cava, after he had cut off the heart of a living dog;
which he suspected to be chyle, and afterwards traced to its
source from the thoracic duct: this duct had been seen near
an hundred years before in a horse by Eustachius, who speaks
of it as a vein of a particular structure, but without know-
ing any thing of its termination or use.

285
PART III. OF THE ABDOMEN.
The lower part of this duct being usually
larger than any other part of it, has been nam-
ed receptaculum chyli, or Pecquet's receptacle, in
honour of the anatomist who first discovered it
in 1651. In some quadrupeds, in turtle and in
fish, this enlargement * is more considerable in
proportion to the size of the dud, than it usu-
ally is in the human subject, where it is not com-
monly found large enough to merit the name of
receptaculum.
Opportunities of observing the lacteals in the
human subject do not often occur; but they
may be easily demonstrated in a dog or any other
quadruped that is killed two or three hours af-
ter feeding upon milk; for then they appear fill-
ed with white chyle.
But these lacteals which we have described, as
passing from the intestines through the mesen-
tery to the thoracic duct, compose only a part of
a system of vessels which perform the office of
absorption, and which constitute, with their
common trunk, the thoracic duct, and the
conglobate glands that are dispersed through the
body, what may be styled the lymphatic system.
So that what is said of the structure of one of
these series of vessels may very properly be ap-
plied to that of the other.
The lymphatics veins (K) are minute pellu-
cid
* Hewson's Exp. Inq. Part II.
(K) The arteries in their course through the body becom-
ing gradually too minute to admit the red globules of the
blood, 

286 
PART III. OF THE ABDOMEN. 
cid tubes, which like the lacteals, direct their
course towards the centre of the body, where
they pour a colourless fluid into the thoracic duct.
The lymphatics from all the lower parts of the
body gradually unite as they approach this duct,
into which they enter by three or four very large
trunks, that seem to form the lower extremity
of this canal, or receptaculum chyli, which may
be considered as the great trunk of the lympha-
tic system. The lacteals open into it near the
same place; and the lymphatics, from a large
share of the upper parts of the body, pour their
lymph into different parts of this duct as it runs
upwards, to terminate in the left subclavian vein.
The lymphatics from the right side of the neck,
thorax, and right arm, &c. terminate in the
right subclavian vein.
As the lymphatics commonly lie close to the
large blood-vessels, a ligature passed round the
crural
blood, have then been styled capillary or lymphatic arteries.
The vessels which are here described as constituting the lym-
phatic system, were at first supposed to be continued from
those arteries, and to convey back the lymph, either into the
red veins or the thoracic duct; the office of absorption hav-
ing been attributed to the red veins. But we know that the
lymphatic veins are not continuations of the lymphatic arteries,
but that they constitute the absorbent system. There are still,
however, some very respectable names among the anatomists
of the present age, who contend, that the red veins act like-
wise as absorbents:—but it seems to have been clearly prov-
ed, that the red veins do absorb no where but in the caver-
nous cells of the penis, the erection of which is occasioned
by a distention of those cells with arterial blood. 

287
PART III. OF THE ABDOMEN.
crural artery in a living animal, by including the
lymphatics, will occasion a distention of these
vessels below the ligature, so as to demonstrate
them with ease; and a ligature passed round the
thoracic duct, instantly after killing an animal,
will, by stopping the course of its contents into
the subclavian vein, distend not only the lacteals,
but also the lymphatics in the abdomen and
lower extremities, with their natural fluids (L).
The coats of these vessels are too thin to be
separated from each other; but the mercury they
are capable of sustaining, proves them to be ve-
ry strong; and their great power of contraction,
after undergoing considerable distention, toge-
ther with the irritability with which Baron Hal-
ler found them to be endued *, seems to render
it probable, that like the blood-vessels, they have
a muscular coat.
The lymphatics are nourished after the same
manner as all the other parts of the body. For
even the most minute of these vessels are pro-
bably supplied with still more minute arteries
and veins. This seems to be proved by the in-
flammation of which they are susceptible; and
the
(L) In the dead body they may be easily demonstrated by
opening the artery ramifying through any viscus, as in the
spleen, for instance, and then throwing in air; by which
the lymphatics will be distended. One of them may be
punctured, and mercury introduced into it through a blow-
pipe. 
* Sur le movement du fang Ex. 295, 298.

288 
PART III. OF THE ABDOMEN. 
the painful swellings which sometimes take place
in lymphatic vessels, prove that they have nerves
as well as blood-vessels.
Both the lacteals, lymphatics, and thoracic
duct, are furnished with valves, which are much
more common in these vessels than in the red
veins. These valves are usually in pairs, and
serve to promote the course of the chyle and
lymph towards the thoracic duct, and to pre-
vent its return. Mention has been made of the
glands, through which the lacteals pass in their
course through the mesentery; and it is to be ob-
served, that the lymphatics pass through similar
glands in their way to the thoracic duct. These
glands are all of a conglobate kind, but the
changes which the chyle and lymph undergo in
their passage through them, have not yet been
ascertained.
The lymphatic vessels begin from surfaces and
cavities in all parts of the body as absorbents.
This is a fact now universally allowed; but
how the fluids they absorb are poured into those
cavities, is a subject of controversy. The con-
tents of the abdomen, for instance, were de-
scribed as being constantly moistened by a very
thin watery fluid. The same thing takes place
in the pericardium, pleura, and all the other ca-
vities of the body, and this watery fluid is the
lymph. But whether it is exhaled into those
cavities through the minute ends of arteries, or
transuded through their coats, are the points in
2 dispute.


289
PART III. OF THE ABDOMEN.
dispute. We cannot here be permitted to re-
late the many ingenious arguments that have
been advanced in favour of each these opinions;
nor is it perhaps of consequence to our present
purpose to enter into the dispute. It will be suffi-
cient if the reader can form an idea of what the
lymph is, and of the manner in which it is ab-
sorbed.
The lymph, from its transparency and want of
colour, would seem to be nothing but water;
and hence the first discoverers of these vessels stiled
them ductus aquosi but experiments prove, that
the lymph of an healthy animal coagulates by
being exposed to the air, or a certain degree of
heat, and likewise by being suffered to rest ; seem-
ing to agree in this property with that part of the
blood called the coagulable lymph.—This proper-
ty of the lymph leads to determine its use, in
moistening and lubricating the several cavities of
the body in which it is found; and for which,
by its gelatinous principle, it seems to be much
better calculated than a pure and watery fluid
would be, for such it has been supposed to be by
some anatomists.
The mouths of the lymphatics and lacteals,
by acting as capillary tubes, seem to absorb the
lymph and chyle somewhat in the same manner
as a capillary tube of glass, when put into a
bason of water, is enabled to attract the wa-
ter into it to a certain height, but it is pro-
bable that they likewise possess a living power,
T which


290 
PART III. OF THE ABDOMEN. 
which assists in performing this office. In
the human body the lymph or the chyle, is pro-
bably conveyed upon this principle as far as the
first pair of valves, which seem to be placed not
far from the orifice of the absorbing vessel, whe-
ther lymphatic or lacteal: and the fluid will then
be propelled forwards, by a continuation of the
absorption at the orifice. But this does not seem
to be the only inducement to its progress to-
wards the thoracic duct; these vessels have pro-
bably a muscular coat, which may serve to press
the fluid forwards from one pair of valves to ano-
ther; and as the large lymphatic vessels and the
thoracic duct are placed close to the large
arteries, which have a considerable pulsa-
tion, it is reasonable to suppose, that they de-
rive some advantage from this situation.
SECT. XV. Of the Generative Organs; of Con-
ception, &c.
§ 1. The Male Organs.
The male organs of generation have been
usually divided into the parts which serve to pre-
pare the semen from the blood, and those which
are distended to convey it into the womb. But
it seems to be more proper to distinguish them
into the preparing, the containing, and the ex-
pelling parts, which are the different offices of the
testes, the vesiculæ seminales, and the penis; and
this

251
PART III. OF THE ABDOMEN.
this is the order in which we propose to describe
them.
The testes are two glandular bodies, serving
to secrete the semen from the blood. They are
originally formed and lodged within the cavity
of the abdomen; and it is not till after the child
is born, or very near that time, that they begin
to pass into the groin, and from thence into the
scrotum (M). By this disposition they are very
wisely protected from the injuries to which they
would be liable to be exposed, from the different
positions of the child at the time of parturition.
The testicles in this state are loosely attached
to the psoæ muscles, by means of the peritonæ-
um by which they are covered; and they are at
this time of life connected in a very particular
T2 manner
(M) It sometimes happens in differing ruptures, that the
intestine is found in the same sac, and in contact with the testis.
This appearance was at first attributed to a supposed lacera-
tion of the peritonæum; but later observations, by pointing
out the situation of the testicles in the fœtus, have led to prove,
the testis, as it descends into the scrotum, carries with
it a portion or elongation of the peritonæum, which becomes
its tunica vaginalis, or a kind of sac, in which the testicle is
lodged, as will be explained in the course of this section.
The communication between this sac and the cavity of the
abdomen, is usually soon cut off; but in some subjects it con-
tinues open during life; and when an hernia or descent of the
intestine takes place in a such subject, it does not push down
a portion of the peritonæum before it, as it must otherwise
necessarily do, but passes at once through this opening, and
comes in contact with the naked testicle, constituting that
particular species of rupture called hernia congenita.

292 
PART III. OF THE ABDOMEN. 
manner to the parietes of the abdomen, and like-
wise to the scrotum, by means of a substance
which Mr. Hunter calls the ligament or guberna-
culum testis, because it connects the testis with
the scrotum, and directs its course in its descent.
This gubernaculum is of a pyramidal form, with
its bulbous head fixed to the lower end of the
testis and epididymis, and loses its lower and
slender extremity in the cellular membrane of the
scrotum. It is difficult to ascertain what the
structure and composition of this gubernaculum
is, but it is certainly vascular and fibrous; and,
from certain circumstances, it would seem to be
in part composed of the cremaster muscle, run-
ning upwards to join the lower end of the testis.
We are not to suppose that the testicle, when
descended into the scrotum, is to be seen loose as
a piece of gut or omentum would be in a com-
mon hernial sac. We have already observed,
that during its residence in the cavity of the ab-
domen it is attached to the peritonæum, which
descends with it; so that when the sac is com-
pleted in the scrotum, the testicle is at first at-
tached only to the posterior part of it, while the
fore part of it lies loose, and for some time af-
fords a communication with the abdomen. The
spermatic chord, which is made up of the sper-
matic artery and vein, and of the vas deferens or
excretory duct of the testis, is closely attached
behind to the posterior part of this elongation of
the peritonæum. But the fore part of the peri-
toneal

293
PART III. OF THE ABDOMEN.
toneal sac, which is at first loose and not attached
to the testicle, closes after a certain time, and be-
comes united the posterior part, and thus per-
fectly surrounds the testicle as it were in a
purse.
The testicles of the fœtus differ only in their
size and situation from those of the adult. In
their passage from the abdomen they descend
through the abdominal rings into the scrotum,
where they are supported and defended by vari-
ous integuments.
What the immediate cause of this descent is,
has not yet been satisfactorily determined. It
has been ascribed to the effects of respiration, but
the testicles have sometimes been found in the
scrotum before the child has breathed; and it
does not seem to be occasioned by the action of
the cremaster muscle, because the same effect
would be liable to happen to the hedge-hog, and
some other quadrupeds, whose testicles remain in
the abdomen during life.
The scrotum, which is the external or com-
mon covering of both testicles, is a kind of sac
formed by the common integuments, and exter-
nally divided into two equal parts by a promi-
nent line called raphe.
In the inner part of the scrotum we meet with
a cellular coat called dartos (N), which by its
duplicature
(N) The dartos has usually been considered as a muscle,
and is described as such both by Douglas and Winslow. But
there 

294 
PART III.OF THE ABDOMEN. 
duplicature divides the scrotum into two equal
parts, and forms what is called septum scroti,
which  corresponds with the raphe. The collap-
sion which is so often observed to take place in
the scrotum of the healthy subject, when excit-
ed by cold or by the stimulus of venery, seems
to be very properly attributed to the contrac-
tile motion of the skin, and not to any muscular
fibres, as is the cafe in dogs and some other quad-
rupeds.
The scrotum, then, by means of its septum,
is found to make two distinct bags, in which the
testicles, invested by their proper tunics, are se-
cured lodged and separated from each other.
These coats are the cremaster, the tunica vagina-
lis, and the tunica albuginea. The first of these
is composed of muscular fibres, and is to be con-
sidered only as a partial covering of the testis;
for it surrounds only the spermatic chord, and
terminates upon the upper and external parts of
the tunica vaginalis testis, serving to draw up
and suspend the testicle (O). The tunica vaginalis
testis has already been described as being a thin
production
there being no part of the scrotum of the human subject
which can be said to consist of muscular fibres, Albinus and
Haller have very properly omitted to describe the dartos as
a muscle, and consider it merely as a cellular coat.
(O) The cremaster muscle is composed of a few fibres
from the obliquus internus abdominis, which uniting with a
few from the transversalis, descend upon the spermatic chord,
and are insensibly lost upon the tunica vaginalis of the testi-
cle. It serves to suspend and draw up the testicle.

295
PART III. OF THE ABDOMEN.
production of the peritonæum, loosely adhering
every where to the testicle, which it includes as
it were in a bag. The tunica albuginea is a firm,
white, and very compact membrane of a glis-
tening appearance, which immediately invests
the body of the testis and the epididymus; serv-
ing in some measure to connect them to each
other, but without extending itself at all to the
spermatic chord. This tunica albuginea serves
to confine the growth of the testis and epididy-
mus within certain limits, and by giving them
a due degree of firmness, enables them to per-
form their proper functions.
Having removed this last tunic, we discover
the substance of the testicle itself, which appears
to be made up of an infinite number of very
elastic filaments, which may be best distinguish-
ed after macerating the testicle in water. Each
testicle is made up of the spermatic artery and
vein, and the excretory vessels or tubuli semini-
feri. There are likewise a great number of ab-
sorbent vessels, and some branches of nerves to be
met with in the testicles.
The spermatic arteries arise one on each side
from the aorta, generally about an inch below
the emulgents. The right spermatic vein com-
monly passes into the vena cava; but the left
spermatic vein usually empties itself into the
emulgent on that side; and it is supposed to take
this course into the emulgent, that it may avoid
passing 

296 
PART III. OF THE ABDOMEN. 
passing over the aorta, which it would be oblig-
ed to do in its way to the vena cava.
The blood is circulated very slowly through
the spermatic artery, which makes an infinite
number of circumvolutions in the substance of
the testicle, where it deposites the semen, which
passes through the tubuli seminiferi. These tu-
buli seminiferi are seen running in short waves
from the tunica albuginea to the axis of the testi-
cle ; and are divided into distinct portions by
certain thin membranous productions, which
originate from the tunica albuginea. They at
length unite, and by an infinite number of con-
volutions form a sort of appendix to the testis
called epididymis (P), which is a vascular body
of an oblong shape, situated upon the superior part
of each testicle. These tubuli of the epididymis
at length form an excretory duct called vas de-
ferens, which ascends towards the abdominal
rings, with the other parts that make up the
spermatic chord, and then a separation takes
place; the nerves and blood-vessels passing on to
their several terminations, and the vas deferens
going to deposit its semen in the vesiculæ semi-
nales, which are two soft bodies of a white and
convoluted appearance externally, situated ob-
liquely between the rectum and the lower part
of
(P) The testicles were named didymi by the ancients, and
the name of this part was given to it on account of its situa-
tion upon the testicle.

297
PART III. OF THE ABDOMEN.
of the bladder, arid uniting together at the lower
extremity. From these reservoirs (Q), which
are
(Q) That the bags called vesiculæ seminales are reservoirs
of semen, is a circumstance which has been by anatomists
universally believed. Mr. J. Hunter, however, from several
circumstances, has been induced to think this opinion erro-
neous.
He has examined these vesiculæ in people who have died
suddenly, and he found their contents to be different in their
properties from the semen. In those who had lost one of
the testicles, or the use of one of them, by disease, both the
vesiculæ were full, and their contents similar. And in a
lusus naturæ, where there was no communication between
the vasa deferentia and vesiculæ, nor between the vesiculæ
and penis, the same thing took place.
From these observations, he thinks we have a presumptive
proof, That the semen can be absorbed in the body of the
testicle and in the epididymis, and that the vesiculæ secrete
a mucus which they are capable of absorbing when it cannot
be made use of: That the semen is not retained in reservoirs
after it is secreted, and kept there till it is used; but that it
is secreted at the time, in consequence of certain affections
of them, and stimulating the testicles to this action.
He corroborates his observations by the appearance on
dissection in other animals; and here he finds, That the shape
and contents of the vesiculæ vary much in different animals,
while the semen in most of them he has examined is nearly
the same: That the vasa deferentia in many animals do not
communicate with the vesiculæ: That the contents of the
vesiculæ of castrated and perfect animals are similar, and
nearly equal in quantity, in no way resembling the semen
as emitted from the animal in coitu, or what is found in the
vas deferens after death. He observes likewise, that the
bulb of the urethra of perfect males is considerably larger
than in castrated animals.
From the whole, he thinks the following inferences may
be 

298 
PART III. OF THE ABDOMEN.
are plentifully supplied with blood-vessels and
nerves, the semen is occasionally discharged
through two short passages, which open into the
urethra
be fairly drawn: That the bags called vesiculæ seminales are
not seminal reservoirs, but glands secreting a peculiar mucus;
and that the bulb of the urethra is properly speaking the
receptacle of the semen, in which it is accumulated previous
to ejection.
But although he has endeavoured to prove that the vesi-
culæ do not contain the semen, he has not been able to as-
certain their particular use. He thinks, however, we may
be allowed upon the whole to conclude, that they are, toge-
ther with other parts, subservient to the purposes of gene-
ration.
Although the author has treated this subject very ably,
and made many ingenious observations, some things may be
objected to what he has advanced; of which the following
are a few: That those animals who have bags called vesiculæ
seminales perform copulation quickly; whereas others that
want them, as in the dog kind, are tedious in copulation:
That in the human body, at least, there is a free communica-
tion between the vasa deferentia and vesiculæ; and in ani-
mals where the author has observed no communication be-
tween the vasa deferentia and vesiculæ, there may be a com-
munication by vessels not yet discovered, and which may be
compared to the hepato-cystic ducts in fowls and fishes:
That the fluid in the end of the vasa deferentia and the vesi-
culæ seminales are similar, according to the author's own ob-
servation: That the vesiculæ in some animals increase and
decrease with the testicle at particular seasons: That in birds
and certain fishes, there is a dilatation of the ends of the vasa
deferentia, which the author himself allows to be a reser-
voir for the semen.
With respect to the circumstance of the bulb of the ure-
thra answering the purpose of a reservoir, the author has
mention no facts which tend to establish this opinion. See
Observations on certain Parts of the Animal Oeconomy.

299
PART III. OF THE ABDOMEN. 
urethra close to a little eminence called verumon-
tanum.
Near this eminence we meet with the pros-
tate, which is situated at the neck of the
bladder, and is described as being of a glandu-
lar structure. It is shaped somewhat like a heart
with its small end foremost, and inverts the ori-
gin of the urethra. Internally it appears to be
of a firm substance, and composed of several fol-
licles, secreting a whitish viscid fluid, that is dis-
charged by ten or twelve excretory ducts into
the urethra, on each side of the openings of the
vesiculæ seminales at the same time, and from the
same causes that the semen is expelled. As this
latter fluid is found to be exceedingly limpid in
the vesiculæ seminales of the dead subject, it
probably owes its whiteness and viscidity to this
liquor of the prostate.
The penis, which is to be considered as the
vehicle or active organ of procreation, is com-
posed of two columns, the corpora cavernosa,
corpus spongiosum. The corpora cavernosa,
which constitute the greatest part of the penis,
may be described as two cylindrical ligamentous
tubes, each of which is composed of an infinite
number of minute cells of a spongy texture,
which communicate with each other. These
two bodies are of a very pliant texture, and ca-
pable of considerable distention: and being unit-
ed laterally to each other, occasion by this union
a space above and another below. The upper-
and 

300 
PART III. OF THE ABDOMEN. 
most of these spaces is filled by the blood vessels,
and the lower one, which is larger than the
other, by the urethra and its corpus spongiosum.
These two cavernous bodies are at first only se-
parated by a partition of tendinous fibres, which
allow them to communicate with each other; but
they afterwards divaricate from each other like
the branches of the letter Y, and diminishing
gradually in size, are attached, one on each side,
by means of the ligamentum suspensorium penis
to the ramus ischii, and to the inferior portion of
the os pubis.
The corpus spongiosum penis, or corpus spon-
giosum urethræ, as it is styled by some authors,
begins as soon as the urethra has passed the pros-
tate, with a thick origin almost like a heart, first
under the urethra, and afterwards above it, be-
coming gradually thinner, and surrounding the
whole canal of the urethra, till it terminates in a
considerable expansion, and constitutes what is
called the glans penis, which is exceedingly vas-
cular, and covered with papillæ like the tongue.
The cuticle which lines the inner surface of
the urethra, is continued over the glans in the
same manner as it is spread over the lips.
The penis is invested by the common integu-
ments, but the cutis is reflected back every where
from the glans as it is in the eye-lids; so that it
covers this part, when the penis is in a relaxed
state, as it were with a hood, and from this use is
called prepuce.
The 

301
PART III. OF THE ABDOMEN.
The prepuce is tied down to the under part
of the glans by a small ligament called frænum,
which is in fact only a continuation of the cuticle
and cutis. There are many simple sebaceous
follicles called glandulæ odoriferæ, placed round
the basis of the glans; and the fluid they secrete
serves to preserve the exquisite sensibility of this
part of the penis, and to prevent the ill effects
of attrition from the prepuce.
The urethra may be defined to be a membran-
ous canal, passing from the bladder through the
whole extent of the penis. Several very small
openings, called lacunæ, communicate with this
canal, through which a mucus is discharged into
it; and besides these, there are two glands, first
described by Cowper, as secreting a fluid for lu-
bricating the urethra, and called Cowper's glands
(R); and Littre * speaks of a gland situated
near the prostate, as being destined for the same
use.
The urethra being continued from the neck
of the bladder, is to be considered as making part
of the urinary passage; and it likewise affords a
conveyance to the semen, which we have observ-
ed is occasionally discharged into it from the ve-
siculæ seminales. The direction of this canal
being first under and then before the pubis, oc-
casions
(R) Both Heister and Morgagni observe, that they have
sometimes not been able to find these glands; so that they do
not seem to exist in all subjects.
* Memories de l' Acad. Royale des Sciences, 1700.

302 
PART III. OF THE ABDOMEN. 
casions a winding in its course from the blad-
der to the penis not unlike the turns of the let-
ter S.
The penis has three pair of muscles, the erec-
tores, acceleratores, and transversales. They
push the blood from the crura to the fore part of
the corpora cavernosa. The first originate from
the tuberosity of the ischium, and terminate in
the corpora cavernosa. The acceleratores arise
from the sphincter, and by their insertion serve
to compress the bulbous part of the urethra;
and the transversales are destined to afford a pas-
sage to the semen, by dilating the canal of the
urethra.
The arteries of the penis are chiefly derived
from the internal iliacs. Some of them are sup-
posed to terminate by pabulous orifices within
the corpora cavernosa and corpus spongiosum;
and others terminate in veins, which at last make
up the vena magna dorsi penis, and other small-
er veins, which are in general distributed in like
order with the arteries.
Its nerves are large and numerous. They
rise from the great sciatic nerve, and accom-
pany the arteries in their course through the
penis.
We have now described the anatomy of this
organ; and there only remains to be explained,
how it is enabled to attain that degree of firmness
and distension which is essential to the great work
of generation.
The 

303
PART III. OF THE ABDOMEN.
The greatest part of the penis has been spoken
of as being of a spongy and cellular texture,
plentifully supplied with blood-vessels and nerves,
and as having muscles to move it in different di-
rections. Now, the blood is constantly passing
into its cells through the small branches of the
arteries which which open into them, and is
from thence as constantly returned by the veins,
so long as the corpora cavernosa and corpus spon-
giosum continue to be in a relaxed and pliant
state. But when, from any nervous influence,
or other means, which it is not necessary here
to define or explain, the erectores penis, ejacu-
latores seminis, levatores ani, &c. are induced
to contract, the veins undergo a certain degree
of compression, and the passage of the blood
through them is so much impeded, that it col-
lects in them in a greater proportion than they
are enabled to carry off, so that the penis gradu-
ally enlarges; and being more and more forcibly
drawn up against the os pubis, the vena magna
itself is at length compressed, and the penis be-
comes fully distended. But as the causes which
first occasioned this distension subside, the penis
gradually returns to its state of relaxation.
§ 2. Female Organs of Generation.
Anatomical writers usually divide the fe-
male organs of generation into external and inter-
nal. In the first division they include the mons
3 veneris, 

304 
PART III. OF THE ABDOMEN. 
veneris, labia pudendi, perinæum, clitoris, nymphæ,
and canunculæ myrtiformes; and in the latter, the
vagina; with the uterus and its appendages.
The mons veneris, which is placed on the upper
part of the symphysis pubis, is internally com-
posed of adipose membranes, which makes it
soft and prominent: it divides into two parts
called labia pudendi, which descending towards
the rectum, from which they are divided by the
perinæeum, form what is called the fourchette.
The perinæum is that fleshy space which extends
about an inch and an half from the fourchette to
the anus, and from, thence about two inches to
the coccyx.
The labia pudendi being separated, we observe
a sulcus called fossa magni; in the upper part of
which is placed the clitoris, a small round spongy
body, in some measure resembling the male pe-
nis, but impervious, composed of two corpora
cavernosa arising from the tuberosities of the
ossa ischii; furnished with two pair of muscles,
the erectores clitoridis, and the sphincter or con-
strictor ostii vaginæ; and terminating in a glans,
which is covered with its prepuce. From the
lower part, on each side of the fossa, pass the
nymphæ, two membranous and spongy folds
which seem destined for useful purposes in partu-
rition, by tending to enlarge the volume of the
vagina as the child's head passes through it. Be-
tween these, about the middle of the fossa mag-
na, we perceive the orifice of the vagina or os ex-
2 ternum,


305
PART III. OF THE ABDOMEN.
ternum, closed by folds and wrinkles; and about
half an inch above this, and about an inch be-
low the clitoris, appears the meatus urinarius or
orifice of the urethra, much shorter, though
somewhat larger, than in men, with a little pro-
minence at its lower edge, which facilitates the
introduction of the catheter.
The os externum is surrounded internally by
several membranous folds called carunculæ myr-
tiformes, which are partly the remains of a thin
membrane called hymen, that covers the vagina
in children. In general the hymen is sufficiently
open to admit the passage of the menses, if
it exists at the time of their appearance; some-
times, however, it has been found perfectly
closed.
The vagina, situated between the urethra and
the rectum, is a membranous cavity, surround-
ed especially at its external extremity with a
spongy and vascular substance, which is covered
by the sphincter ostii vaginæ. It terminates in
the uterus, about half an inch above the os tin-
cæ, and is wider and shorter in women who
have had children than in virgins.
All these parts are plentifully supplied with
blood-vessels and nerves. Around the nymphæ
there are sebaceous follicles, which pour out a
fluid to lubricate the inner surface of the vagina;
and the meatus urinarius, like the urethra in the
male subject, is constantly moistened by a mu-
U cus,


306 
PART III. OF THE ABDOMEN. 
cus, which defends it against the acrimony of
the urine.
The uterus is a hollow viscus, situated in the
hypogastric region, between the rectum and blad-
der. It is destined to receive the first rudiments
of the fœtus, and to assist in the developement
of all its parts, till it arrives at a state of per-
fection, and is fitted to enter into the world,
at the time appointed by the wise Author of
nature.
The uterus, in its unimpregnated state, resem-
bles a pear in shape, somewhat flattened, with
its fundus or bottom part turned towards the ab-
domen, and its cervix or neck surrounded by the
vagina. The entrance into its cavity forms a
little protuberance, which has been compared to
the mouth of a tench, and is therefore called os
tinæ.
The substance of the uterus, which, is of a
considerable thickness, appears to be composed
of muscular and small ligamentous fibres, small
branches of nerves, some lymphatics, and with
arteries and veins innumerable. Its nerves are
chiefly derived from the intercostal, and its arte-
ries and veins from the hypogastric and spermatic.
The membrane which lines its cervix, is a con-
tinuation of the inner membrane of the vagina;
but the outer surface of the body of the uterus
is covered with the peritonæum, which is re-
flected over it, and descends from thence to the
intestinum rectum. This duplicature of the
peritonæum,

307
PART III. OF THE ABDOMEN.
peritonæum, by passing off from the sides of
the uterus to the sides of the pelvis, is there
firmly connected, and forms what are called
ligamenta uteri lata; which not only serve to
support the uterus, but to convey nerves and
blood-vessels to it.
The ligamenta uteri rotunda arise from the
sides of the fundus uteri, and passing along with-
in the fore-part of the ligamenta lata, descend
through the abdominal rings, and terminate in
the substance of the mons veneris. The sub-
stance of these ligaments is vascular, and al-
though both they and the ligamenta lata admit
the uterus in the virgin state, to move only about
an inch up and down, yet in the course of preg-
nancy they admit of considerable distension, and
after parturition return nearly to their original
state with surprising quickness.
On each side of the inner surface of the ute-
rus, in the angle near the fundus, a small orifice
is to be discovered, which is the beginning of
one of the tubæ fallopianæ. Each of these tubes,
which are two in number, passing through the
substance of the uterus, is extended along the
broad ligaments, till it reaches the edge of the
pelvis, from whence it reflects back; and turn-
ing over behind the ligaments, about an inch of
its extremity is seen hanging loose in the pelvis,
near the ovarium. These extremities, having
a jagged appearance, are called fimbriæ, or morsus
diaboli. Each tuba Fallopiana is usually about
U2 three 


308 
PART III. OF THE ABDOMEN. 
three or four inches long. Their cavities are
at first very small, but become gradually larger,
like a trumpet, as they approach the fimbriæ.
Near the fimbriæ of each tuba Fallopiana,
about an inch from the uterus, is situated an oval
body called ovarium, of about half the size of
the male testicle. Each of these ovaria is cover-
ed by a production of the peritonæum, and
hangs loose in the pelvis. They are of a flat
and angular form, and appear to be composed
of a white and cellular substance, in which we
are able to discover several minute vesicles filled
with a coagulable lymph, of an uncertain num-
ber, commonly exceeding 12 in each ovary. In
the female of riper years, these vesicles become
exceedingly turgid, and a kind of yellow coa-
gulum is gradually formed within one of them,
which increases for a certain time. In concep-
tion, one of these mature ova is supposed to be
impregnated with the male semen, and to be
squeezed out of its nidus into the Fallopian
tube; after which the ruptured part forms a
substance which in some animals is of a yel-
low colour, and is therefore called corpus lute-
um; and it is observable, that the number of
these tears or fissures in the ovarium, constantly
corresponds with the number of fœtuses exclud-
ed by the mother.
§ 3. Of 

309
PART III. OF THE ABDOMEN. 
§ 3. Of Conception.
Man, being ever curious and inquisitive, has
naturally been led to enquire after the origin of
his existence; and the subject of generation has
employed the philosophical world in all ages:
but in following nature up to her minute re-
cesses, the philosopher soon finds himself bewil-
dered, and his imagination often supples that
which he so eagerly wishes to discover, but which
is destined perhaps never to be revealed to him.
Of the many theories which have been formed
on this subject, that of the ancient philosophers
seems to have been the most simple: they con-
sidered the male semen as alone capable of form-
ing the fœtus, and believed that the female only
afforded it a lodging in the womb, and supplied
it with a nourishment after it was perfectly form-
ed. This opinion, however, soon gave place to
another, in which the female was allowed a more
considerable share in conception.
This second system considered the fœtus as
being formed by the mixture of the seminal li-
quor of both sexes, by a certain arrangement of
its several particles in the uterus. But in the
16th century, vesicles or eggs were discovered
in the ovaria or female testicles; the fœtus had
been found sometimes in the abdomen, and
sometimes in the Fallopian tubes; and the two
former opinions were exploded in favour of a
new 

210 
PART III. OF THE ABDOMEN. 
new doctrine. The ovaria were compared to a
bunch of grapes, being supposed to consist of ve-
sicles, each of which had a stalk; so that it might
be disengaged without hurting the rest, or spill-
ing the liquor it contained. Each vesicle was
said to include a little animal, almost complete
in all its parts; and the vapour of the male se-
men being conveyed to the ovarium, was sup-
posed to produce a fermentation in the vesicle,
which approached the nearest to maturity; and
inducing it to disengage itself from the ovarium,
it passed into the tuba Fallopiana, through
which it was conveyed to the uterus. Here it
was supposed to take root like a vegetable seed,
and to form, with the vessels originating from
the uterus, what is called the placenta; by means
of which the circulation is carried on between
the mother and the fœtus.
This opinion, with all its absurdities, conti-
nued to be almost universally adopted till the
close of the same century, when Lieuwenhoeck,
by means of his glasses, discovered certain
opake particles, which he described as so many
animalcula, floating in the seminal fluid of the
male.
This discovery introduced a new schism among
the philosophers of that time, and gave rise to
a system which is not yet entirely exploded.
According to this theory the male semen passing
into the tubæ Fallopianæ, one of the animalcula
penetrates into the substance of the ovarium, 
and

211
Part III. OF THE ABDOMEN.
and enters into one of its vesicles or ova. This
impregnated ovum is then squeezed from its
husk, through the coats of the ovarium, and be-
ing seized by the fimbriæ, is conducted through
the tube to the uterus, where it is nourished till
it arrives at a state of perfection. In this sys-
tem there is much ingenuity; but there are cer-
tain circumstances supposed to take place, which
have been hitherto inexplicable. A celebrated
modern writer, M. Buffon, endeavours to re-
store, in some measure, the most ancient opi-
nion, by allowing the female semen a share in
this office; asserting, that animalcula or organic
particles are to be discovered in the seminal li-
quor of both sexes: he derives the female semen
from the ovaria, and he contends that no ovum
exists in those parts. But in this idea he is evi-
dently mistaken; and the opinion now most ge-
nerally adopted is, that an impregnation of the
ovum, by the influence of the male semen, is
essential to conception (S). That the ovum is to
be impregnated, there can be no doubt; but as
the manner in which such an impregnation is
supposed to take place, and the means by which
the ovum afterwards get into the Fallopian tube,
and
(S) The learned Abbe Spallanzani has thrown much light
on this curious subject, and has proved by a variety of ex-
periments than the animalcule exists entire in the female ovum,
and that the male seed is only necessary to vivify and put it
in motion.—His experiments and observations are worthy
of the attentive perusal of every physiologist.

212 
PART III. OF THE ABDOMEN.  
and from thence into the uterus, are still found-
ed chiefly on hypothesis, we will not attempt to
extend farther the investigation of a subject con-
cerning which so little can be advanced with cer-
tainty.
§ 4. Of the Fœtus in Utero.
Opportunities of dissecting the human
gravid uterus occurring but seldom, the state of
the embryo (T) immediately after conception
cannot be perfectly known.
When the ovum descends into the uterus, it
is supposed to be very minute; and it is not till
a considerable time after conception that the
rudiments of the embryo begin to be ascer-
tained.
About the third or fourth week the eye may
discover the first lineaments of the fœtus; but
these lineaments are as yet very imperfect, it be-
ing only about the size of a house-fly. Two
little vessels appear in an almost transparent jel-
ly; the largest of which is destined to become
the head of the fœtus, and the other smaller one
is reserved for the trunk. But at this period no
extremities are to be seen; the umbilical cord
appears only as a very minute thread, and the
placenta
(T) The rudiments of the child are usually distinguished by
this name till the human figure can be distinctly ascertained,
and then it has the appellation of fœtus.

213
PART III. OF THE ABDOMEN.
placenta does not yet absorb the red particles of
the blood. At six weeks, not only the head but
the features of the face begin to be developed.
The nose appears like a small prominent line,
and we are able to discover another line under it,
which is destined for the separation of the lips.
Two black points appear in the place of eyes,
and two minute holes mark the ears. At the
sides of the trunk, both above and below, we
see four minute protuberances, which are the
the rudiments of the arms and legs. At the end
of eight weeks the body of the fœtus is upwards
of an inch in length, and both the hands and
feet are to be distinguished. The upper extre-
mities are found to increase faster than the lower
ones, and the separation of the fingers is accom-
plished sooner than that of the toes.
At this period the human form may be deci-
sively ascertained;—all the parts of the face may
be distinguished, the shape of the body is clearly
marked out, the haunches and the abdomen are
elevated, the fingers and toes are separated from
each other, and the intestines appear like minute
threads.
At the end of the third month, the fœtus mea-
sures about three inches; at the end of the fourth
month, five inches; in the fifth month, six or
seven inches; in the sixth month, eight or nine
inches; in the seventh month, eleven or twelve
inches; in the eighth month, fourteen or fif-
teen inches; and at the end of the ninth month,
or 

214 
PART III. OF THE ABDOMEN. 
or full time, from eighteen to twenty-two in-
ches. But as we have not an opportunity of ex-
amining the same fœtus at different periods of
pregnancy, and as their size and length may be
influenced by the constitution and mode of life
of the mother, calculations of this kind must be
very uncertain.
The fœtus during all this time assumes an oval
figure, which corresponds with the shape of the
uterus. Its chin is found reclining on its breast
with its knees drawn up towards its chin, and its
arms folded over them. But it seems likely,
that the posture of some of these parts is varied
in the latter months of pregnancy, so as to cause
those painful twitches which its mother usually
feels from time to time. In natural cases, its
head is probably placed towards the os tincæ from
the time of conception to that of its birth;
though formerly it was considered as being plac-
ed towards the fundis uteri till about the eighth
or ninth mouth, when the head, by becom-
ing specifically heavier than the other parts
of the body, was supposed to be turned down-
wards.
The capacity of the uterus increases in pro-
portion to the growth of the fœtus, but without
becoming thinner in its substance, as might na-
turally be expected. The nourishment of the
fœtus, during all this time, seems to be derived
from the placenta, which appears to be original-
ly formed by that part of the ovum which is
next 

215
Part III. OF THE ABDOMEN.
next the fundis uteri. The remaing part of the
ovum is covered by a membrane called spongy
chorion (U); within which is another called true
chorion, which includes a third termed amnios (V):
this contains a watery fluid, which is the liquor
amnii (W), in which the fœtus floats till the
time of its birth. On the side next the fœtus, the
placenta is covered by the amnios and true cho-
rion; on the fide next the mother it has a pro-
duction continued from the spongy chorion.
The
(U) Dr. Hunter has described this as a lamella from the
inner surface of the uterus. In the latter months of preg-
nancy it becomes gradually thinner and more connected with
the chorion : he has named it menbrana caduca, or decidua,
as it is cast off with the placenta. Signior Scarpa, with
more probability, considers it as being composed of an in-
spissated coagulable lymph.
(V) In some quadrupeds, the urine appears to be con-
veyed from the bladder through a canal called urachus, to
the alantois, which is a reservoir, resembling a large and
blind gut, situated between the chorion and amnios. The
human fœtus seems to have no such reservoir, though some
writers hare supposed that it does exist. From the top of the
bladder a few longituddinal fibres are extended to the umbilical
chord; and these fibres have been considered as the urachus,
though without having been ever found pervious.
(W) The liquor amnii coagulates like the lymph. It has
been supposed to pass into the œsophagus, and to afford nou-
rishment to the fœtus; but this does not seem probable.
Children have come into the world without an œsophagus,
or any communication between the stomach and the mouth;
but there has been no well attested instance of a child's hav-
ing been born without a placenta; and it does not seem like-
ly, that any of the fluid can be absorbed through the pores
of the skin, the skin in the fœtus being every where covered
with a great quantity of mucus. 

216 
PART III. OF THE ABDOMEN. 
The amnios and chorion are remarkably thin and
transparent, having no blood-vessels entering in-
to their composition. The spongy chorion is
opake and vascular.
In the first months of pregnancy, the involu-
cra bear a large proportion to their contents; but
this proportion is afterwards reversed, as the fœ-
tus increases in bulk.
The placenta, which is the medium through
which the blood is conveyed from the mother
to the fœtus, and the manner in which this
conveyance takes place, deserve next to be con-
sidered.
The placenta is a broad, flat, and spongy sub-
stance, like a cake, closely adhering to the inner
surface of the womb, usually near the fundus,
and appearing to be chiefly made up of the rami-
fications of the umbilical arteries and vein, and
partly of the extremities of the uterine vessels.
The arteries of the uterus discharge their con-
tents into the substance of this cake; and the
veins of the placenta, receiving the blood either
by a direct communication of vessels, or by ab-
sorption, at length form the umbilical vein,
which passes on to the sinus of the vena porta,
and from thence to the vena cava, by means of
the canalis venosus, a communication that is
closed in the adult. But the circulation of the
blood through the heart is not conducted in the
fœtus as in the adult: in the latter the blood is 
carried from the right auricle of the heart through
the 

217
PART III. OF THE ABDOMEN.
the pulmonary artery, and is returned to the left
auricle by the pulmonary vein; but a dilatation
of the lungs is essential to the passage of the
blood through the pulmonary vessels, and this
dilatation cannot take place till after the child is
born and has respired. This deficiency, howe-
ver, is supplied in the fœtus by the immediate
communication between the right and left auri-
cle, through an oval opening, in the septum
which divides the two auricles, called foramen
ovale. The blood is likewise transmitted from
the pulmonary artery to the aorta, by means of
a duct called canalis arteriosus, which, like the
canalis venosus, and foramen ovale, gradually
closes after birth.
The blood is returned again from the fœtus
through two arteries called the umbilical arteries,
which arise from the iliacs. These two vessels
taking a winding course with the vein, form
with that, and the membranes by which they
are surrounded, what is called the umbilical chord.
These arteries, after ramifying through the sub-
stance of the placenta, discharge their blood into
the veins of the uterus; in the same manner as
the uterine arteries discharged their blood into
the branches of the umbilical vein. So that the
blood is constantly passing in at one side of the
placenta and out at the other; but in what par-
ticular manner it gets through the placenta is a
point not yet determined.
2 EXPLA-


218 
PART III. OF THE ABDOMEN.  
EXPLANATION of PLATES XXV. XXVI. AND XXVII.
PLATE XXV.
FIG. 1. Shows the Contents of the Thorax and
Abdomen in situ.
1. Top of the trachea, or wind-pipe. 22,
The internal jugular veins. 33, The subcla-
vian veins. 4, The vena cava descendens. 5,
The right auricle of the heart. 6, The right
ventricle. 7, Part of the left ventricle. 8, The
aorta descendens. 9, The pulmonary artery.
10, The right lung, part of which is cut off to
show the great blood-vessels. 11, The left lung,
entire. 1212, The anterior edge of the dia-
phragm. 1313, The two great lobes of the
liver. 14, The ligamentum rotundum. 15,
The gall-bladder. 16, The stomach. 1717,
The jejunum and ilium. 18, The spleen.
FIG. 2. Shows the Organs subservient to the
Chylopoietic Viscera,—with those of the U-
rine and Generation.
11, The under side of the two great lobes
of the liver. a, Lobulus Spigelii. 2, The li-
gamentum rotundum. 3, The gall-bladder.
4, The pancreas, 5, The spleen. 66, The
kidneys. 7, The aorta descendens. 8, Vena
cava

319
PART III. OF THE ABDOMEN.
cava ascendens. 99, The renal veins covering
the arteries. 10, A probe under the spermatic
vessels and a bit of the inferior mesenteric artery,
and over the ureters. 1111, The ureters.
12 12, The iliac arteries and veins. 13, The
rectum intestinum. 14, The bladder of urine.
FIG 3. Shows the Chylopoietic Viscera, and
Organs subservient to them, taken out of the
Body entire.
AA the under side of the two great lobes of 
the liver. B, Ligamentum rotundum. C, The
gall-bladder. D, Ductus cysticus. E, Ductus
hepaticus. F, Ductis communis choledochus.
G, Vena portarum. H, Arteria hepatica. II,
The stomach. KK, Venæ & arteriæ gastro-
epiploicæ, dextræ & sinistræ. LL, Venæ &
arteriæ coronariæ ventriculi. M, The spleen.
N N, Mesocolon, with its vessels. OOO, In-
testinum colon. P, One of the ligaments of
the colon, which is a bundle of longitudinal
muscular fibres. QQQQ, Jejunum and
ilium. R R, Sigmoid flexure of the colon, with
the ligament continued, and over S, The rec-
tum intestinum. TT, Levatores ani. U,
Sphincter ani. V, The place to which the pro-
state glandis connected. W, The anus.
FIG. 4.

320 
PART III. OF THE ABDOMEN.  
FIG 4. Shows the heart of a Fœtus at the full
time, with the Right Auricle cut open to
show the Foramen Ovale, or passage between
both Auricles.
a, The right ventricle, b, The left ventricle.
cc, The outer side of the right auricle stretched
out. d d, The posterior side, which, forms the
anterior side of the septum. e, The foramen
ovale, which the membrane or valve which co-
vers the left side. f, Vena cava inferior passing
through g, A portion of the diaphragm.
FIG. 5. Shows the Heart and Large Vessels of a
Fœtus at the full time.
a, The left ventricle. b, The right ventri-
cle. c, A part of the right auricle. d, Left
auricle, ee, The right branch of the pulmona-
ry artery. f, Arteria pulmonalis. g g, The
left branch of the pulmonary artery, with a num-
ber of its largest branches dissected; from the
lungs. h, The canalis arteriosus. i, The arch
of the aorta. kk, The aorta descendens. l, The
left subclavian artery. m, The left carotid ar-
tery. n, The right carotid artery. o. The
right subclavian artery. p, The origin of the
right carotid and right subclavian arteries in one
common trunk. q, The vena cava superior or
descendens. r, The right common subclavian
vein. S, The left common subclavian vein.
N. B. All the parts described in this figure
are to be found in the adult, except the canalis
arteriosus. 
PLATE

ANATOMY 
PLATE XXV

 

321
PART III. OF THE ABDOMEN.
PLATE XXVI.
FIG. 1. Exhibits the more superficial Lympha-
tic Vessels of the Lower Extremity.
A, The spine of the os ilium. B, The os
pubis. C, The iliac artery. D, The knee, EEF,
Branches of the crural artery. G, The muscu-
lus gastrocnemius. H, The tibia. I, The ten-
don of the musculus tibialis anticus. On the
out-lines, 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.
c, The lymphatic vessels which lie between the
skin and the muscles of the thigh, ff, 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 towards the inside of the groin at (i),
opens into the lymphatic gland (k). l, l, Lym-
phatic glands in the groin, which are common
to the lymphatic vessels of the genitals and those
of the lower extremity, m, n, A plexus of
lymphatic vessels passing on the inside of the iliac
artery.
X FIG. 2. 
 

322 
PART III. OF THE ABDOMEN.  
FIG. 2. Exhibits a Back View of the Lower Ex-
tremity, dissected so as to show the deeper-
seated Lymphatic Vessels which accompany
the arteries.
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. FF, The two cut
surfaces of the triceps muscle, which was divid-
ed to show the lymphatic vessels that pass through
its perforation along with the crural artery. G,
The edge of the musculus gracilis. H, The gas-
troncnemius and soleus, much shrunk by being
dried, and by the soleus being separated from
the tibia to expose the vessels. I, The heel.
K, The sole of the foot. L, The superficial
lymphatic vessels passing over the knee, to get
to the thigh. On the out-lines; M, The poste-
rior tibial artery. a, A lymphatic vessel accom-
panying the posterior tibial artery, b, The same
vessel crossing the artery, c, A small lymphatic
gland, through which this deep-seated lympha-
tic vessel passes. d, The lymphatic vessel pas-
sing under a small part of the soleus, which
is left attached to the bone, the rest being re-
moved. e, The lymphatic vessel crossing the
popliteal artery. f, g, h, Lymphatic glands in
the ham, through which the lymphatic vessel
passes. i, The lymphatic vessel passing with 
the

323
PART III. OF THE ABDOMEN.
the crural artery, through the perforation of the
triceps muscle. k, The lymphatic vessel, af-
ter it had passed the perforation of the triceps,
dividing into branches which embrace the ar-
tery (l). m, A lymphatic gland belonging to
the deep-seated lymphatic vessel. At this
place those vessels pass to the fore-part of the
groin, where they communicate with the super-
ficial lymphatic vessel appearing on the brim of
the pelvis.
FIG. 3. Exhibits the Trunk of the Human Sub-
ject prepared to show the Lymphatic Vessels
and the Ductus Thoracicus.
A, The neck. B B, The two jugular veins.
C, The vena cava superior. DDDD, The
subclavian veins. E, The beginning of the
aorta, pulled to the left side by means of a liga-
ture, in order to show the thoracic duct behind
it. F, The branches arising from the curvature
of the aorta. GG, The two carotid arteries.
HH, the first ribs, II, The trachea. KK,
The spine.  L, The vena azygos. MM,
The descending aorta. N, The cœliac artery,
dividing into three branches. O, The superior
mesenteric artery. P, The right crus diaphrag-
matis. QQ, The two kidneys. R, The right
emulgent artery. SS, The external iliac arte-
ries, g d, The musculi psoæ. T, The inter-
nal iliac artery. U, The cavity of the pelvis.
X2 XX, The


324 
PART III. OF THE ABDOMEN. 
XX, The spine of the os ilium. YY, The
groins. a, A lymphatic gland in the groin, in-
to which lymphatic vessels from the lower ex-
tremity are seen to enter. b b, The lymphatic
vessels of the lower extremities passing under
Poupart's ligament. cc, A plexus of the lym-
phatic vessels lying on each side of the pelvis. d,
The psoas muscle with lymphatic vessels lying
upon its inside. e, A plexus of lymphatics,
which having passed over the brim of the pel-
vis at (c), having entered the cavity of the pel-
vis, and received the lymphatic vessels belong-
ing to the viscera contained in that cavity, next
ascends, and passes behind the iliac artery to (g).
f, some lymphatic vessels of the left side pas-
ssing over the upper part of the os sacrum, to
meet those of the right side. g, The right
psoas, with a large plexus of lymphatics lying on
its inside. hh, The plexus lying on each side
of the spine. iii, Spaces occupied by the lym-
phatic glands. k, The trunk of the lacteals,
lying on the under side of the superior mesente-
ric artery. l, The same dividing into two
branches, one of which passes on each side of
the aorta ; that of the right side being seen to
enter the thoracic duct at (m). m, The thora-
cic beginning from the large lymphatics. n,
The duct passing under the lower part of the crus
diaphragmatis, and under the right emulgent ar-
tery. o, The thoracic duct penetrating the
thorax. p, Some lymphatic vessels joining that
duct

325
PART III. OF THE ABDOMEN.
duct in the thorax. q, The thoracic duct pas-
sing 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 lym-
phatic vessels passing upon the trachea from the
thyroid gland to the thoracic duct.
PLATE XXVII.
FIG 1. Represents the Under and Posterior
Side of the Bladder of Urine, &c.
a, The bladder. b b, The insertion of the
uterers, cc, The vasa deferentia, which con-
vey the semen from the testicles to d d, The ve-
siculæ seminales,—and pass through e, The pro-
state gland, to discharge themselves into f, The
beginning of the urethra.
FIG 2. A transverse Section of the Penis.
g g, Corpora carvernosa penis. h, Corpus
cavernosum urethræ. i, Urethra. k, Septum
penis. ll, The septum between the corpus ca-
vernosum urethræ and that of the penis.
FIG. 3. A longitudinal Section of the Penis
mm, The corpora carvernosa penis, divided
by o, The septum penis, n, The corpus ca-
vernosum glandis, which is the continuation of
that of the urethra.
FIG. 4. 

326 
PART III. OF THE ABDOMEN. 
FIG. 4. Represents the Female Organs of Ge-
neration.
a, That side of the uterus which is next the
os sacrum. 1, Its fundus. 2, Its cervix. b b,
The Fallopian or uterine tubes, which open in-
to the cavity of the uterus;—but the other end
is open within the pelvis, and surrounded by
cc, The fimbriæ. d d, The ovaria. e, The
os internum uteri, or mouth of the womb. ff,
The ligamenta rotunda, which passes without the
belly, and is fixed to the labia pudendi. gg, The
cut edges of the ligamenta lata which connects
the uterus to the pelvis. h, The inside of the
vagina. i, The orifice of the urethra. k, The
clitoris surrounded by (l,) The præputium.
mm, The labia pudendi. nn, The nymphæ.
FIG. 5. Shows the Spermatic Ducts of the Tes-
ticle filled with Mercury.
A, The vas deferens. B, Its beginning,
which forms the posterior part of the epididy-
mis. C, The middle of the epididymis, com-
posed of serpentine ducts. D, The head or an-
terior part of the epididymis unravelled, eeee,
The whole ducts which compose the head of
the epiddiymis unravelled. ff, The vasa defe-
rentia. gg, Rete testis. hh, Some rectilineal
ducts

ANATOMY
Plate XXV

 

ANATOMY
Plate XXVII 

 

327
PART III. OF THE ABDOMEN.
ducts which send off the vasa deferentia. ii,
The substance of the testicle.
FIG. 6. The right Testicle entire, and the Epi-
didymis filled with Mercury.
A, The beginning of the vas deferens. B,
The vas deferens ascending towards the abdomen.
C, The posterior part of the epididymis, named
globus minor. D, The spermatic vessels inclosed in
cellular substance. E, The body of the epidy-
dimis. F, Its head, named globus major. G, Its
beginnning from the testicle. H, The body of
the testicle, inclosed in the tunica albuginea.
PART IV.

328 
PART IV. OF THE THORAX. 
PART IV. 
OF THE THORAX.
THE thorax, or chest, is that cavity
of the trunk which extends from the cla-
vicles, or the lower part of the neck, to the dia-
phragm, and includes the vital organs, which
are the heart and lungs; and likewise the tra-
chea and œsophagus.—This cavity is formed by
the ribs and vertebræ of the back, covered by a
great number of muscles, and by the common
integuments, and anteriorly by two glandular
bodies called the breasts. The spaces between
the ribs are filled by the muscular fibres, which
from their situation are called intercostal muscles.
SECT. I. Of the Breasts.
The breasts may be defined to be two large
conglomerate glands, mixed with a good deal of
adipose membrane. The glandular part is com-
posed of an infinite number of minute arteries,
veins, and nerves.
The arteries are derived from two different
trunks; one of which is called the internal, and
the other the external, mammary artery. The
first of these arises from the subclavian, and the
latter from the axillary,
The 

329
Part IV. OF THE THORAX.
The veins every where accompany the arte-
ries, and are distinguished by the same name.
The nerves are chiefly from the vertebral pairs.
Like all other conglomerate glands, the breasts
are made up of a great many small distinct glands,
in which the milk is secreted from the ultimate
branches of arteries. The excretory ducts of
these several glands gradually uniting as they ap-
proach the nipple, form the tubuli lactiferi,
which are usually more than a dozen in number,
and open at its apex, but have little or no com-
munication, as has been supposed, at the root of
the nipple. These ducts, in their course from the
glands, are surrounded by a ligamentary elastic
substance, which terminates with them in the
nipple. Both this substance, and the ducts
which it contains, are capable of considerable
extension and contraction; but in their natural
state are moderately corrugated, so as to prevent
an involuntary flow of milk, unless the distend-
ing force be very great from the accumulation of
too great a quantity.
The whole substance of the nipple is very
spongy and elastic: its external surface is une-
ven, and full of small tubercles. The nipple is
surrounded with a disk or circle of a different
colour, called the areola; and on the inside of
the skin, under the areola, are many sebaceous
glands, which pour out a mucus to defend the
areola and nipple: for the skin upon these parts
is 

330 
PART IV. OF THE THORAX. 
is very thin; and the nervous papillæ lying very
bare, are much exposed to irritation.
The breasts are formed for the secretion of
milk, which is destined for the nourishment of
the child for some time after its birth. This se-
cretion begins to take place soon after delivery,
and continues to flow for many months in very
large quantities, if the woman suckles her child.
The operation of suction depends on the prin-
ciples of the air-pump, and the flow of milk
through the lactiferous tubes is facilitated by their
being stretched out.
The milk, examined chemically, appears to
be composed of oil, mucilage, and water, and
of a considerable quantity of sugar. The ge-
nerality of physiologists have supposed that, like
the chyle, it frequently retains the properties of
the aliment and medicines taken into the sto-
mach; but from some late experiments *, this
supposition appears to be ill-founded.
SECT. II. Of the Pleura.
THE cavity of the thorax is every where lin-
ed by a great membrane of a firm texture call-
ed pleura. It is composed of two distinct porti-
ons or bags, which, by being applied to each
other laterally, form a septum called mediastinum;
which
* Journ. de Med. 1781.

331
PART IV. OF THE THORAX.
which divides the cavity into two parts, and is
attached posteriorly to the vertebræ of the back,
and anteriorly to the sternum. But the two la-
minæ of which this septum is formed, do not
every where adhere to each other; for at the
lower part of the thorax they are separated, to
afford a lodgement to the heart; and at the upper
part of the cavity, they receive between them
the thymus.
The pleura is plentifully supplied with arte-
ries and veins from the internal mammary and
the intercostals. Its nerves, which are very in-
considerable, are derived chiefly from the dorsal
and intercostal nerves.
The surface of the pleura, like that of the pe-
ritonæum and other membranes lining cavities,
is constantly bedewed with a serous moisture (W)
which prevents adhesion of the viscera.
The mediastinum, by dividing the breast into
two cavities, obviates many inconveniences, to
which we should otherwise be liable. It pre-
vents the two lobes of the lungs from compres-
sing each other when we lie on one side; and
consequently contributes to the freedom of res-
piration, which is disturbed by the least pressure
on the lungs. If the point of a sword pene-
trates between the ribs into the cavity of the tho-
rax, the lungs on that side cease to perform their
office;
(W) When this fluid is exhaled in too great a quantity, or
is not properly carried off, it accumulates and constitutes
the hydrops pectoris. 

352 
PART IV.OF THE THORAX.  
office; because the air being admitted through
the wound, prevents the dilatation of that lobe;
while the other lobe, which is separated from it
by the mediastinum, remains unhurt, and con-
tinues to perform its function as usual.
SECT. II. Of the Thymus.
THE thymus is a glandular substance, the use
of which is not perfectly ascertained, its excre-
tory duct not having yet been discovered. It is
of an oblong figure, and is larger in the fœtus
and in young children than in adults, being some-
times nearly effaced in very old subjects. It is
placed in the upper part of the thorax, between
the two laminæ of the mediastinum; but at first
is not altogether contained within the cavity of
the chest, being found to border upon the upper
extremity of the sternum.
SECT. IV. Of the Diaphragm.
THE cavity of the thorax is separated from that
of the addomen, by a fleshy and membranous
substance called the diaphragm or midriff. The
greatest part of it is composed of muscular fibres;
and on this account systematic writers usually
place very properly among the muscles. Its mid-
dle part is tendinous, and it is covered by the
pleura above, and by the peritonæum below.
It seems to have been improperly named septum
transversum,

333
PART IV. OF THE THORAX.
trasversum, as it does not make a plane trans-
verse division of the two cavities, but forms a
kind of vault, the fore-part of which is attach-
ed to the sternum. Laterally it is fixed to the
last of the true ribs, and to all the false ribs; and
its lower and posterior part is attached to the
vertebræ lumborum, where it may be said to be
divided in two portions or crura (X).
The principal arteries of the diaphragm are
derived from the aorta, and its veins pass into
the vena cava. It nerves are chiefly derived
from the cervical pairs. It affords a passage to
the vena cava through its tendinous part, and to
the œsophagus through its fleshy portion. The
aorta passes down behind it between its cura.
The diaphragm not only serves to divide the
thorax from the abdomen, but by its muscular
structure is is rendered one of the chief agents
in respiration. When its fibres contract, its
convex side, which is turned towards the tho-
rax, becomes gradually flat, and by increasing
the cavity of the breast, affords room for a com-
plete dilatation of the lungs, by means of the
air which is then drawn into them by the act of
inspiration. The fibres of the diaphragm then
relax; and as it resumes its former state, the ca-
vity
(X) Anatomical writers have usually described the dia-
phragm as being made up of two muscles united by a middle
tendon; and these two portions or crura form what they
speak of as the inferior muscle, arising from the sides and
fore part of the vertebræ.

334 
PART IV. OF THE THORAX.  
vity of thorax becomes gradually diminished,
and the air is driven out again from the lungs by
a motion contrary to the former one, called ex-
spiration.
It is in some measure, by means of the dia-
phragm, that we void the fæces at the anus, and
empty the urinary bladder. Besides these offices,
the acts of coughing, sneezing, speaking, laugh-
ing, gaping, and sighing, could not take place
without its assistance; and the gentle pressure
which all the abdominal viscera receive from its
constant and regular motion, cannot fail to assist
in the performance of the several functions which
were ascribed to those viscera.
SECT. V. Of the Trachea.
THE trachea or windpipe, is a cartilaginous
and membranous canal, through which the air
passes into the lungs. Its upper part, which is
called the larynx, is composed of five cartilages.
The uppermost of these cartilages is placed over
the glottis or mouth of the larynx, and is called
epiglottis, which has been before spoken of, as
closing the passage to the lungs in the act of
swallowing. At the sides of the glottis are
placed the two arytenoide cartilages, which are
of a very complex figure, not easy to be de-
scribed. The anterior and larger part of the
larynx is made up of two cartilages; one of
which is called thyroides or scutiformis, from its
being

335
PART IV. OF THE THORAX.
being shaped like a buckler; and the other cri-
coides or annularis, from its resembling a ring.
Both these cartilages may be felt immediately
under the skin, at the fore-part of the throat,
and the thyroides, by its convexity, forms an
eminence called pomum adami, which is usually
more considerable in the male than in the female
subject.
All these cartilages are united to each other by
means of very elastic, ligamentous fibres; and
are enabled, by the assistance of their several
muscles, to dilate or contract the passage of
the larynx, and to perform that variety of mo-
tion which seems to point out the larynx as the
principal organ of the voice; for when the air
passes out through a wound in the trachea, it pro-
duces no sound.
These cartilages are moistened by a mucus,
which seems to be secreted by minute glands si-
tuated near them. The upper part of the trachea
is covered anteriorly and laterally by a consider-
able body, which is supposed to be of a glandu-
lar structure, and from its situation near the thy-
roid cartilage is called the thyroid gland; though
its excretory duct has not yet been discovered,
or its use ascertained.
The glottis is interiorly covered by a very fine
membrane, which is moistened by a constant
supply of a watery fluid. From the larynx the
canal begins to take the name of trachea or as-
pera arteria, and extends from thence as far down 

336 
PART IV. OF THE THORAX. 
as the third or fourth vertebra of the back, where
it divides into two branches, which are the right
and left bronchial tube. Each of these bronchi
(Y), ramifies through the substance of that lobe
of the lungs to which it is distributed, by in-
finite number of branches, which are formed of
cartilages separated from each other like those of
the trachea, by an intervening membranous and
ligamentary substance. Each of these cartilages
is of an angular figure; and as they become gra-
dually less and less, in their diameter, the lower
ones are in some measure received into those
above them, when the lungs, after being inflat-
ed, gradually collapse by the air being pushed
out from them in expiration. As the branches
of the bronchi become more minute, their car-
tilages become more and more angular and mem-
branous, till at length they are found to be per-
fectly membranous, and at last become invisible.
The trachea is furnished with fleshy or mus-
cular fibres; some of which pass through its
whole extent longitudinally, while the others
are carried round, it in a circular direction; so
that by the contraction or relaxation of these fi-
2 bres;
(Y) The right bronchial tube is usually found to be some-
what shorter and thicker than the left; and M. Portal, who
has published a memoir on the action of the lungs on the
aorta in respiration, observes, that the left bronchial tube is
closely connected by the aorta; and from some experiments
he is induced to conclude, that in the first respirations, the
air only enters into the right lobe of the lungs. Memoires
de l' Academie Royale des Sciences, 1769.

337
PART IV. OF THE THORAX.
bres, it is enabled to shorten or lengthen itself,
and likewise to dilate or contract the diameter of
its passage.
The trachea and its branches, in all their ra-
mifications, are furnished with a great number of
small glands which are lodged in their cellular
substance, and discharge a mucous fluid on the
inner surface of these tubes.
The cartilages of the trachea, by keeping it
constantly open, afford a free passage to the air,
which we are obliged to be incessantly respiring;
and its membranous part, by being capable of
contraction and dilatation, enables us to receive
and expel the air in a greater or less quantity,
and with more or less velocity, as may be requir-
ed in singing or in declamation. This membran-
ous structure of the trachea posteriorly, seems
likewise to assist in the descent of the food, by
preventing that impediment to its passage down
the œsophagus, which might be expected if the
cartilages were complete rings.
The trachea receives its arteries from the ca-
rotid and subclavian arteries, and its veins pass
into the jugulars. Its nerves arise from the re-
current branch of the eighth pair, and from the
cervical plexus.
SECT. VI. Of the Lungs.
The lungs fill the greater part of the cavity of
the breast. They are of a soft and spongy tex-
Y ture, 


338 
PART IV. OF THE THORAX. 
ture, and are divided into two lobes, which are
separated from each other by the mediastinum,
and are externally covered by a production of
the pleura. Each of these is divided into two
or three lesser lobes; and we commonly find
three in the right side of the cavity, and two in
the left.
To discover the structure of the lungs, it is
required to follow the ramifications of the bron-
chi, which were described in the last section.
These becoming gradually more and more mi-
nute, at length terminate in the cellular spaces or
vesicles, which make up the greatest part of the
substance of the lungs, and readily communicate
with each other.
The lungs seem to possess but little sensibility.
Their nerves, which are small, and few in num-
ber, are derived from the intercostal and eighth
pair. This last pair having reached the thorax,
sends off a branch on each side of the trachea,
called the recurrent, which reascends at the back
of the trachea, to which it furnishes branches in
its ascent, as well as to the œsophagus, but it is
chiefly distributed to the larynx and its muscles.
By dividing the recurrent and superior laryngeal
nerves at their origin, an animal is deprived of
its voice.
There are two series of arteries which carry
blood to the lungs: these are the arteriæ bron-
chiales, and the pulmonary artery.
The 

339
PART IV. OF THE THORAX.
The arteriæ bronchiales begin usually by two
branches; one of which commonly arises from
the right intercostal, and the other from the trunk
of the aorta: but sometimes there are three of
these arteries, and in some subjects only one.
The use of these arteries is to serve for the nou-
rishment of the lungs, and their ramifications are
seen creeping every where on the branches of the
bronchi. The blood is brought back from them
by the bronchial vein into the vena azygos.
The pulmonary artery and vein are not in-
tended for the nourishment of the lungs; but
the blood in its passage through them is destined
to undergo some changes, or to acquire certain
essential properties (from the action of the air),
which it has lost in its circulation through
the other parts of the body. The pulmo-
nary artery receives the blood from the right
ventricle of the heart, and dividing into two
branches, accompanies the bronchi every where,
by its ramifications through the lungs; and the
blood is afterwards conveyed back by the pulmo-
nary vein, which gradually forming a consider-
able trunk, goes to empty itself into the left
ventricle of the heart; so that the quantity of
blood which enters into the lungs, is perhaps
greater than that which is sent in the same pro-
portion of time through all the other parts of
the body.
Y2 SECT.


340 
PART IV. OF THE THORAX. 
SECT. VII. Of Respiration.
RESPIRATION constitutes one of those func-
tions which are properly termed vital, as being
essential to life; for to live and to breathe are in
fact synonymous terms. It consists in an alter-
nate contraction and dilatation of the thorax, by
first inspiring air into the lungs, and then expell-
ing it from them in exspiration.
It will perhaps be easy to distinguish and point
out the several phenomena of respiration; but
to explain their physical cause will be attended
with difficulty: for it will naturally be enquir-
ed, how the lungs, when emptied of the air,
and contracted by exspiration, become again in-
flated, they themselves being perfectly passive?
How the ribs are elevated in opposition to their
own natural situation? and why the diaphragm
is contracted downwards, towards the abdomen?
Were we to assert that the air, by forcing its way
into the cavity of the lungs, dilated them, and
consequently elevated, the ribs, and pressed down
the diaphragm, we should speak erroneously.
What induces the first inspiration, it is not easy
to ascertain; but after an animal has once respir-
ed, it would seem likely that the blood, after ex-
spiration, finding its passage through the lungs
obstructed, becomes a stimulus, which induces
the intercostal muscles and the diaphragm to con-
tract, and enlarge the cavity of the thorax, in
consequence

341
PART IV. OF THE THORAX. 
consequence perhaps of a certain nervous influ-
ence, which we will not here attempt to explain.
The air then rushes into the lungs; every branch
of the bronchial tubes, and all the cellular spaces
into which they open, become fully dilated;
and the pulmonary vessels being equally distend-
ed, the blood flows through them with ease. But
as the stimulus which first occasioned this dila-
tation ceases to operate, the muscles gradually
contract, the diaphragm rises upwards again, and
diminishes the cavity of the chest; the ribs re-
turn to their former state; and as the air passes
out in exspiration, the lungs gradually collapse,
and a resistance to the passage of the blood again
takes place. But the heart continuing to receive
and expel the blood, the pulmonary artery be-
gins again to be distended, the stimulus is re-
newed, and the same process is repeated, and
continues to be repeated, in a regular succession,
during life: for though the muscles of respiration,
having a mixed motion, are (unlike the heart)
in some measure dependent on the will, yet no
human being, after having once respired, can
live many moments without it. In an attempt
to hold one's breath, the blood soon begins to
distend the veins, which are, unable to empty
their contents into the heart; and we are able
only, during a very little time, to resist the sti-
mulus to inspiration. In drowning, the circu-
lation seems to be stopped upon this principle;
and in hanging, the pressure made on the jugu-
lar 

342 
PART IV. OF THE THORAX.  
lar veins, may co-operate with the stoppage of
respiration in bringing on death.
Till within these few years physiologists were
entirely ignorant of the use of respiration. It
was at length discovered in part by the illustrious
Dr. Priestley. He found that the air exspired
by animals was phlogisticated; and that the air
was fitter for respiration, or for supporting ani-
mal life, in proportion as it was freer from the
phlogistic principle. It had long been observ-
ed, that the blood in passing through the lungs
acquired a more florid colour. He therefore
suspected, that it was owing to its having im-
parted phlogiston to the air: and he satisfied
himself of the truth of this idea, by experi-
ments, which showed, that the crassamentum of
extravasated blood, phlogisticated air in propor-
tion as it lost its dark colour. He farther found,
that blood thus reddened had a strong attraction
for phlogiston; insomuch that it was capable of
taking it from phlogisticated air, thereby becom-
ing of a darker colour, from hence it appeared
that the blood, in its circulation through the ar-
terial system, imbibes a considerable quantity of
phlogiston, which is discharged from it to the
air in the lungs.
This discovery has since been prosecuted by
two very ingenious physiologists, Dr. Crawford
and Mr. Elliot. It had been shown by profe-
sors Black and Irvine, that different bodies have
different capacities for containing fire. For ex-
ample,

343
PART IV. OF THE THORAX.
ample, that oil and water, when equally hot to
the sense and the thermometer, contain different
proportions of that principle; and that unequal
quantities of it are required, in order to raise
those substances to like temperatures. The en-
quiries of Dr. Crawford and Mr. Elliot tend to
prove, that the capacities of bodies for contain-
ing fire are diminished by the addition of phlo-
giston, and increased by its separation: the ca-
pacity of calx of antimony, for example, being
greater than that of the antimony itself. Com-
mon air contains a great quantity of fire; com-
bustible bodies very little. In combustion, a
double elective attraction takes place; the phlo-
giston of the body being transferred to the air,
the fire contained in the air to the combustible
body. But as the capacity of the latter is not
increased so much as that of the former is dimi-
nished, only part of the extricated fire will be
absorbed by the body. The remainder therefore
will raise the temperature of the compound; and
hence we may account for the heat attending
combustion. As the use of respiration is to
dephlogisticate the blood, it seems probable, that
a like double elective attraction takes place in
this process; the phlogiston of the blood being
transferred to the air, and the fire contained in
the air to the blood; but with this difference,
that the capacities being equal, the whole of the
extricated fire is absorbed by the latter. The
blood in this state circulating through the body,
imbibes

344 
PART IV. OF THE THORAX.  
imbibes phlogiston, and of course gives out its
fire; part only of which is absorbed by the parts
furnishing the phlogiston; the remainder, as in
combustion, becoming sensible; and is therefore
the cause of the heat of the body, or what is
called animal heat.
In confirmation of this doctrine it may be
observed, that the venous blood contains less
fire than the arterial; combustible bodies less
than incombustible ones; and that air contains
less of this principle, according as it is rendered,
by combination with phlogiston, less fit for res-
piration (Z).
In ascending very high mountains, respiration
is found to become short and frequent, and some-
times to be attended with a spitting of blood.
These symptoms seem to be occasioned by the
air being too rare and thin to dilate the lungs
sufficiently; and the blood gradually accumulat-
ing in the pulmonary vessels, sometimes bursts
through their coats, and is brought up by cough-
ing. This has likewise been accounted for in a
different way, by supposing that the air contain-
ed in the blood, not receiving an equal pressure
from that of the atmosphere, expands, and at
length ruptures the very minute branches of the
pulmonary vessels; upon the same principle that
fruits and animals put under the receiver of an
air-
(Z) See Crawford's Experiments and Observations on
Animal Heat, and Elliot's Philosophical Observations.

345
PART IV. OF THE THORAX.
air-pump, are seen to swell as the outer air be-
comes exhausted. But Dr. Darwin of Litchfield
has lately published some experiments, which
seem to prove, that no air or elastic vapour does
exist in the blood-vessels, as has been generally
supposed: and he is induced to impute the spit-
ting of blood, which has sometimes taken place
in ascending high mountains, to accident, or to
violent exertions; as it never happens to animals
that are put into the exhausted receiver of an air-
pump, where the diminution of pressure is ma-
ny times greater than on the summit of the high-
est mountains.
SECT. VIII. Of the Voice.
RESPIRATION has already been described as
affording us many advantages; and next to that
of life, its most important use seems to be that
of forming the voice and speech. The ancients,
and almost all the moderns, have considered the
organ of speech as a kind of musical instrument,
which may be compared to a flute, to an haut-
boy, to an organ, &c. and they argue after the
following manner.
The trachea, which begins at the root of the
tongue, and goes to terminate in the lungs, may
be compared to the pipe of an organ the lungs di-
lating like bellows during the time of inspiration;
and as the air is driven out from them in exspi-
ration, it finds its passage straitened by the carti-
lages 

346 
PART IV. OF THE THORAX.  
lages of the larynx, against which it strikes. As
these cartilages are more or less elastic, they occa-
sion in their turn more or less vibration in the
air, and thus produce the sound of the voice;
the variation in the sound and tone of which de-
pends on the state of the glottis, which, when
straitened, produces an acute tone, and a grave
one when dilated.
The late M. Ferein communicated to the
French Academy of Sciences a very ingenious
theory on the formation of the voice. He con-
sidered the organ of the voice as a firing, as well
as a wind, instrument; so that what art has hi-
therto been unable to construct, and what both
the fathers Mersenne and Kircher so much wish-
ed to see, M. Ferein imagined he had at length
discovered in the human body. He observes,
that there are at the edges of the glottis certain
tendinous chords, placed horizontally across it,
which are capable of considerable vibration, so
as to produce sound, in the same manner as it is
produced by the strings of a violin or a harpsi-
chord: and he supposes that the air, as it passes
out from the lungs, acts as a bow on these strings,
while the efforts of the breast and lungs regulate
its motion, and produce the variety of tones.
So that according to this system the variation in
the voice is not occasioned by the dilatation or
contraction of the glottis, but by the distension or
relaxation of these strings, the sound being more
or less acute in proportion as they are more or
less 

347
PART IV. OF THL THORAX.
less stretched out. Another writer on this sub-
ject supposes, that the organ of voice is a double
instrument, which produces in unison two sounds
of a different nature; one by means of the air,
and the other by means of the chords of the 
glottis. Neither of these systems, however, are 
universally adopted. They are both liable to 
insuperable difficulties; so that the manner in 
which the voice is formed has never yet been sa-
tisfactorily ascertained: we may observe, how-
ever, that the sound produced by the glottis is 
not articulated. To effect this, it is required to 
pass through the mouth, where it is differently
modified by the action of the tongue, which is 
either pushed against the teeth, or upwards to-
wards the palate; detaining it in its passage, or 
permitting it to flow freely, by contracting or di-
lating the mouth.
SECT. IX. Of Dejection.
By dejection we mean the act of voiding the 
fæces at the anus; and an account of the man-
ner in which this is conducted was reserved for 
this part of the work, because it seemed to re-
quire a knowledge of respiration to be perfectly
understood.
The intestines were described as having a pe-
ristaltic motion, by which the fæces were gra-
dually advancing towards the anus. Now, when-
ever the fæces are accumulated in the intestinum 
rectum

348 
PART IV. OF THE THORAX.  
rectum in a sufficient quantity to become trouble-
some, either by their weight or acrimony, they
excite a certain uneasiness which induces us to
go to stool.—To effect this, we begin by mak-
ing a considerable inspiration; in consequence of
which the diaphragm is carried downwards to-
wards the lower belly; the abdominal muscles
are at the same time contracted in obedience to
the will; and the intestines being compressed on
all sides, the resistance of the sphincter is over-
come, and the fæces pass out at the anus; which
is afterwards drawn up by its longitudinal fibres,
which are called levatores ani, and then by means
of its sphincter is again contracted: but it some-
times happens, as in dysenteries, for instance,
that the fæces are very liquid, and have consi-
derable acrimony; and then the irritation they
occasion is more frequent, so as to promote their
discharge without any pressure from the dia-
phragm or abdominal muscles; and sometimes
involuntarily, as is the case when the sphincter
becomes paralytic.
SECT. X. Of the Pericardium, and of the Heart
and its Auricles.
THE two membranous bags of the pleura,
which were described as forming the mediasti-
num, recede one from the other, so as to afford
a lodgement to a firm membranous sac, in which
the heart is securely lodged; this sac, which is 
the

349
PART IV. OF THE THORAX.
the pericardium, appears to be composed of two
tunics, united to each other by cellular mem-
brane.—The outer coat, which is thick, and in
some places of tendinous complexion, is a pro-
duction of the mediastinum; the inner coat,
which is extremely thin, is reflected over the
auricles and ventricles of the heart, in the same
manner as the tunica conjunctiva, after lining the
eye lids, is reflected over the eye.
This bag adheres to the tendinous part of
the diaphragm, and contains a coagulable lymph,
the liquor pericardii, which serves to lubricate
the heart and facilitate its motions; and seems to
be secreted and absorbed in the same manner as
it is in the other cavities of the body.
The arteries of the pericardium are derived
from the phrenic, and its veins pass into veins of
the same name; its nerves are likewise branches
of the phrenic.
The size of the pericardium is adapted to that
of the heart, being usually large enough to con-
tain it loosely. As its cavity does not extend to
the sternum, the lungs cover it in inspiration;
and as it every where inverts the heart, it effectu-
ally secures it from being injured by lymph, pus,
or any other fluid, extravasated into the cavities
of the thorax.
The heart is a hollow muscle of a conical shape,
situated transversely between the two laminæ of
the mediastinum, at the lower part of the thorax;
having its basis turned towards the right side, and
its

350 
PART IV. OF THE THORAX. 
its point or apex towards the left.—Its lower sur-
face is somewhat flattened towards the diaphragrm
Its basis, from which the great vessels originate,
is covered with fat, and it has two hollow and
fleshy-appendages, called auricles.—Round these
several openings, the heart seems to be of a firm
ligamentous texture, from which all its fibres
seem to originate; and as they advance from
thence towards the apex, the substance of the
heart seems to become thinner.
The heart includes two cavities or ventricles,
which are separated from each other by a fleshy
septum; one of these is called the right and the
other the left, ventricle; though perhaps, with
respect to their situation, it would be more pro-
per to distinguish them into the anterior and pos-
terior ventricles.
The heart is exteriorly covered by a very fine
membrane; and its structure is perfectly muscu-
lar or fleshy, being composed of fibres which
are described as passing in different directions;
some as being extended longitudinally from the
basis to the apex; others, as taking an oblique or
spiral course; and a third sort as being placed in
a transverse direction (A).—Within the two
ventricles we observe several furrows; and there
are
(A) Authors differ about the course and distinctions of
these fibres; and it seems right to observe, that the structure
of the heart being more compact than that of other muscles,
its fibres are not easily separated. 

351
PART IV. OF THE THORAX.
are likewise tendinous strings, which arise from
fleshy columnæ in the two cavities, and are attach-
ed to the valves of the auricles: That the use of
these and the other valves of the heart may be
understood, it must be observed, that four large
vessels pass out from the basis of the heart, viz.
two arteries and two veins; and that each of
these vessels is furnished with a thin membran-
ous production, which is attached all round to
the borders of their several orifices, from whence
hanging loosely down they appear to be divided
into two or three distinct portions. But as their
uses in the arteries and veins are different, so are
they differently disposed. Those of the arteries
are intended to give way to the passage of the
blood into, them from the ventricles, but to op-
pose its return: and, on the contrary, the valves
of the veins are constructed so as to allow the
blood only to pass into the heart. In consequence
of these different uses, we find the valves of the
pulmonary artery and of the aorta attached to
the orifices of those vessels, so as to have their
concave surfaces turned towards the artery; and
their convex, surfaces, which mutually meet to-
gether, being placed towards the ventricle, only
permit the blood to pass one way, which is into
the arteries. There are usually three of these
valves belonging to the pulmonary artery, and
as many to the aorta; and from their figure they
are called valvulæ semilunares. The communi-
cation between the two great veins and the ven-
tricles

352 
PART IV. OF THE THORAX.  
tricles is by means of the two appendages or au-
ricles into which the blood is discharged; so that
the other valves which may be said to belong to
the veins, are placed in each ventricle, where
the auricle opens into it. The valves in the
right ventricle are usually three in number, and
are named valvulæ tricuspides; but in the left
ventricle we commonly observe only two, and
these are the valvulæ mitrales. The membranes
which form these valves in each cavity are at-
tached so as to project somewhat forward; and
both the tricuspides and the mitrales are connect-
ed with the tendinous strings, which were de-
scribed as arising from the fleshy columnæ. By
the contraction of either ventricle, the blood is
driven into the artery which communicates with
that ventricle; and these tendinous strings being
gradually relaxed as the sides of the cavity are
brought nearer to each other, the valves natu-
rally close the opening into the auricle, and the
blood necessarily directs its course into the then
only open passage, which is into the artery; but
after this contraction, the heart becomes relaxed,
the tendinous strings are again stretched out, and,
drawing the valves of the auricle downwards,
the blood is poured by the veins into the ventri-
cle, from whence, by another contraction, it is
again thrown into the artery, as will be describ-
ed hereafter. The right ventricle is not quite so
long, though somewhat larger, than the left;
but the latter has more substance than the other:
3 and


353
PART IV. OF THE THORAX.
and this seems to be, because it is intended to
transmit the blood to the most distant parts of the
body, whereas the right ventricle distributes it
only to the lungs.
The heart receives its nerves from the par va-
gum and the intercostals. The arteries which
serve for its nourishment are two in number, and
arise from the aorta. They surround in some
measure the basis of the heart, and from this
course are called the coronary arteries. From
these arteries the blood is returned by veins of
the same name into the auricles, and even into the
ventricles.
The muscular bags called the auricles are situ-
ated at the basis of the heart, at the sides of each
other; and, corresponding with the two ventri-
cles, are like those two cavities distinguished in-
to right and left. These sacs, which are inte-
riorly unequal, have externally a jagged appen-
dix; which, from its having been compared to
the extremity of an ear, has given them their
name of auricles.
SECT. XI. Angiology, or a Description of the
Blood-vessels.
The heart has been described as contracting
itself, and throwing the blood from its two
ventricles into the pulmonary artery and the
aorta, and then as relaxing itself and receiv-
ing a fresh supply from two large veins, which
Z are


354 
PART IV. OF THE THORAX.  
are the pulmonary vein and the vena cava. We
will now point out the principal distributions of
these vessels.
The pulmonary artery arises from the right
ventricle by a large trunk, which soon divides
into two considerable branches, which pass to
the right and left lobes of the lungs: each of
these branches is afterwards divided and subdi-
vided into an infinite number of branches and
ramifications, which extend through the whole
substance of the lungs; and from these branches
the blood is returned by the veins, which, con-
trary to the course of the arteries, begin by very
minute canals, and gradually become larger,
forming at length four large trunks called pul-
monary veins, which terminate in the left auricle
by one common opening, from whence the
blood passes into the left ventricle. From this
same ventricle arises the aorta or great artery,
which at its beginning is nearly an inch in dia-
meter : it soon sends off two branches, the coro-
naries, which go to be distributed to the heart
and its auricles. After this, at or about the third
or fourth vertebra of the back, it makes a con-
siderable curvature; from this curvature (B) arise
three
(B) Anatomists usually call the upper part of this curva-
ture aorta ascendens; and the other part of the artery to its
division at the iliacs, aorta descendens: but they differ about
the place where this distinction is to be introduced; and it
seems sufficiently to answer every purpose, to speak only of
the aorta and its curvature. 

355
PART IV. OF THE THORAX.
three arteries; one of which soon divides into
two branches. The first two are the left sub-
clavian and the left carotid, and the third is a
common trunk to the right subclavian and right
carotid; though sometimes both the carotids
arise distinctly from the aorta.
These two carotids ascend within the subcla-
vians, along the sides of the trachea; and when
they have reached the larynx, divide into two
principal branches, the internal and external ca-
rotid. The first of these runs a little way back-
wards in a bending direction; and having reach-
ed the under part of the ear, passes through the
canal into the os petrosum, and entering into the
cavity of the cranium, is distributed to the brain
and the membranes which invelope it, and like-
wise to the eye. The external carotid divides
into several branches, which are distributed to
the larynx, pharynx, and other parts of the
neck; and to the jaws, lips, tongue, eyes,
temples; and all the external parts of the head.
Each subclavian is likewise divided into a
great number of branches. It sends off the ver-
tebral artery, which passes through the openings
we see at the bottom of the transverse processes
of the vertebræ of the neck, and in its course
sends off many ramifications to the neighbour-
ing parts. Some of its branches are distributed
to the spinal marrow, and after a considerable
inflexion it enters into the cranium, and is dis-
tributed to the brain. The subclavian likewise
Z2 sends 


356 
PART IV. OF THE THORAX.  
sends off branches to the muscles of the neck
and the scapula; and mediastinum, thymus, peri-
cardiu, diaphragm, the breasts, and the mus-
cles of the thorax, and even of the abdomen,
derive branches from the subclavian, which are
distinguished by different names, alluding to the
parts to which they are distributed; and the
mammary, the phrenic, the intercostal, &c. But
notwithstanding the great number of branches
which have been described as arising from the
subclavian, it is still a considerable artery when
it reaches the axilla, where it drops its former
name, which alludes to its passage under the cla-
vicle, and is called the axillary artery; from
which a variety of branches are distributed to the
muscles of the breast, scapula, and arm.—But
its main trunk taking the name of brachialis,
runs along on the inside of the arm near the os
humeri, till it reaches the joint of the fore-arm,
and then it divides into branches. This divi-
sion however is different in different subjects;
for in some it takes place higher up and in others
lower down. When it happens to divide above
the joint, it may be considered as a happy dis-
position in case of an accident by bleeding; for
supposing the artery to be unfortunately punc-
tured by the lancet, and that the hæmorrhage
could only be stopped by making a ligature on
the vessel, one branch would remain unhurt,
through which the blood would pass uninterupt-
ed to the fore-arm and hand. One of the two
branches 

357
PART IV. OF THE THORAX.
branches of the brachialis plunges down under
the flexor muscles, and runs along the edge of
the ulna; while the other is carried along the
outer surface of the radius, and is easily felt at
the wrist, where it is only covered by the com-
mon integuments. Both these branches com-
monly unite in the palm of the hand, and form
an arterial arch from whence branches are de-
tached to the fingers.
The aorta, after having given off at its cur-
vature the carotids and subclavians which convey
blood to all the upper parts of the body, descends
upon the bodies of the vertebræ a little to the left,
as far as the os sacrum, where it drops the name of
aorta, and divides into two considerable branches.
In this course, from its curvature to its bifurca-
tion, it sends off several arteries in the following
order: 1. One or two little arteries, first demon-
strated by Ruysch as going to the bronchi, and
called arteriæ bronchinales Ruyschii. 2. The ar-
teriæ œsophageæ. These are commonly three
or four in number. They arise from the fore-
part of the aorta, and are distributed chiefly to
the œsophagus. 3. The inferior intercostal ar-
teries, which are distributed between the ribs in
the same manner as the arteries of the three or
four superior ribs are, which are derived from
the subclavian. These arteries send off branches
to the medulla spinalis. 4. The diaphragmatic
or inferior phrenic arteries, which go to the
diaphragm, stomach, omentum, duodenum,
pancreas 

358 
PART IV. OF THE THORAX. 
pancreas, spleen, liver, and gall-bladder. 5.
The cœliac, which sends off the coronary-sto-
machic, the splenic, and the hepatic artery. 6.
The superior mesenteric artery and small intes-
tines. 7. The emulgents, which go to the kid-
neys. 8. The arteries, which are distributed
to the glandulæ renales. 9. The spermatic.
10. The inferior mesenteric artery, which ra-
mifies through the lower portions of the mesen-
tery and the large intestines.—A branch of this
artery which goes to the rectum is called the in-
ternal hemorrhoidal. 11. The lumbar arteries,
and a very small branch called the sacra, which
are distributed to the muscles of the loins and
abdomen, and to the os sacrum and medulla
spinalis.
The trunk of the aorta, when it has reached
the last vertebra lumborum, or the os sacrum, drops
the name of aorta, and separates into two fork-
ed branches called the iliacs. Each of these soon
divides into two branches; one of which is call-
ed internal iliac, or hypogastric artery, and is dis-
tributed upon the contents of the pelvis and up-
on the muscles on its outer side. One branch,
called pudenda communis, sends small ramifica-
tions to the end of the rectum under the name
of hemorrhoides externæ, and is afterwards dis-
tributed upon the penis. The other branch, the
external iliac, after having given off the cir-
cumflex artery of the os ilium and the epigastric,
which is distributed to the recti-muscles, passes
out 

359
PART IV. OF THE THORAX.
out of the abdomen under Poupart's ligament,
and takes the name of crural artery. It de-
scends on the inner part of the thigh close to
the os femoris, sending off branches to the mus-
cles, and then sinking deeper in the hind part of
the thigh, reaches the ham, where it takes the
name of popliteal: after this it separates into two
considerable branches: one of which is called
the anterior tibial artery; the other divides into
two branches, and these arteries all go to be dis-
tributed to the leg and foot.
The blood, which is thus distributed by the
aorta to all parts of the body, is brought back by
the veins, which are supposed to be continued
from the ultimate branches of arteries; and
uniting together as they approach the heart, at
length from the large trunks, the vena cava
ascendens, and vena cava descendens.
All the veins which bring back the blood from
the upper extremities, and from the head and
breast, pass into the vena cava descendens; and
those which return it from the lower parts of
the body terminate in the vena cava ascendens;
and these two cavas uniting together as they ap-
proach the heart, open by one common orifice
into the left auricle.
It does not here seem to be necessary to fol-
low the different divisions of the veins as we did
those of the arteries; and it will be sufficient to
remark, that in general every artery is accom-
panied by its vein, and that both are distinguished
by 

360 
PART IV. OF THE THORAX. 
by the same name. But, like many other ge-
neral rules, this too has its exceptions (C). The
veins for instance, which accompany the exter-
nal and internal carotid, are not called the car-
toid veins, but the external and internal jugular.
—In the thorax, there is a vein distinguished
by a proper name, and this is the azygos, or ve-
na sine parti. This vein, which is a pretty con-
siderable one, runs along by the right side of
the vertebræ of the back, and is chiefly destin-
ed to receive the blood from the intercostals on
that side, and from the lower half of those on
the left side, and to convey it into the vena cava
descendens. In the abdomen we meet with a
vein, which is still a more remarkable one, and
this is the vena portæ, which performs the office
both of an artery and a vein. It is formed by
a re-union of all the veins which come from the
stomach, intestines, omentum, pancreas, and
spleen, so as to compose one great trunk, which
goes to ramify through the liver; and after hav-
ing deposited the bile, its ramifications unite and
bring back into the vena cava, not only the blood
which the vena portæ had carried into the liver,
but likewise the blood from, the hepatic artery.
Every artery has a vein which corresponds with
it; but the trunks and branches of the veins
are
(C) In the extremities, some of the deep-seated veins,
and all the superficial one, take a course different from
that of the arteries. 

361
PART IV. OF THE THORAX.
are more numerous than those of the arteries.
—The reasons for this disposition are perhaps
more difficult to be explained; the blood in its
course through the veins is much farther remov-
ed from the source and cause of its motion,
which are in the heart, than it was when in the
arteries; so that its course is consequently less
rapid, and enough of it could not possibly be
brought back to the heart in the moment of its
dilatation, to equal the quantity which is driven
into the arteries from the two ventricles, at the
time they contract; and the equilibrium which
is so essential to the continuance of life and
health would consequently be destroyed, if the
capacity of the veins did not exceed that of
the arteries, in the same proportion that the ra-
pidity of the blood's motion through the arteries
exceeds that of its return through the veins.
A large artery ramifying through the body,
and continued to the minute branches of veins,
which gradually unite together to form a large
trunk, may be compared to two trees united to
each other at their tops; or rather as having
their ramifications so disposed that the two trunks
terminate in one common point; and if we
farther suppose, that both these trunks and their
branches are hollow, and that a fluid is inces-
santly circulated through them, by entering into
one of the trunks and returning through the other,
we shall be enabled to conceive how the blood
is 

362 
PART IV. OF THE THORAX. 
is circulated through the vessels of the human
body.
Every trunk of an artery, before it divides,
is nearly cylindrical, or of equal diameter through
its whole length, and so are all its branches
when examined separately. But every trunk
seems to contain less blood than the many
branches do into which that trunk separates;
and each of these branches probably contains
less blood than the ramifications do into which
it is subdivided: and it is the same with the
veins; the volume of their several ramifications,
when considered together, being found to exceed
that of the great trunk which they form by their
union.
The return of the blood through the veins to
the heart, is promoted by the action of the mus-
cles, and the pulsation of the arteries. And
this return is likewise greatly assisted by the
valves which are to be met with in the veins,
and which constitute one of the great distinctions
between them and the arteries. These valves,
which are supposed to be formed by the inner
coat of the veins, permit the blood to flow from
the extremities towards the heart, but oppose its
return. They are most frequent in the smaller
veins. As the column of blood increases, they
seem to become less necessary; and therefore in
the vena cava ascendens, we meet with only one
valve, which is near its origin.
The arteries are composed of several tunics.
Some

363
PART IV. OF THE THORAX.
Some writers enumerate five of these tunics;
but perhaps we may more properly reckon only
three, viz. the nervous, muscular, and cuticular
coats. The veins are by some anatomists de-
scribed as having the same number of coats as
arteries; but as they do not seem to be irrita-
ble, we cannot with propriety suppose them to
have a muscular tunic. We are aware of Dr.
Verschuir's * experiments to prove that the ju-
gular and some other veins possess a certain de-
gree of irritability; but it is certain, that his
experiments, repeated by others, have produc-
ed a different result; and even he himself allows,
that sometimes he was unable to distinguish any
such property in the veins. Both these series of
vessels are nourished by still more minute arteries
and veins, which are seen creeping over their coats,
and ramifying through their whole substance,
and are called vasa vasorum; they have likewise
many minute branches of nerves.
The arteries are much stronger than the veins,
and they seem to require this force to be enabled
to resist the impetus with which the blood circu-
lates through them, and to impel it on towards
the veins.
When the heart contracts, it impels the blood
into the arteries, and sensibly distends them;
and these vessels again contract, as the heart be-
comes relaxed to receive more blood from the
auricles;
* De Arteriarum et Venarum vi irritabili, 4to.

364 
PART IV. OF THE THORAX.  
auricles; so that the cause of the contraction
and dilatation of the arteries seems to be easy
to be understood, being owing in part to
their own contractile power, and in part to
the action of the heart; but in the veins, the ef-
fects of this impulse not being so sensibly felt,
and the vessels themselves having little or no con-
tractile power, the blood seems to flow in a con-
stant and equal stream: and this, together with
its passing gradually from a small channel into a
larger one, seems to be the reason why the veins
have no pulsatory motion, except the large ones
near the heart; and in these it seems to be oc-
casioned by the motion of the diaphragm, and
by the regurgitation of the blood in the cavas.
SECT. XII. Of the Action of the Heart, Auri-
cles, and Arteries.
The heart, at the time it contracts, drives
the blood from its ventricles into the arteries;
and the arteries being thus filled and distended,
are naturally inclined to contract the moment
the heart begins to dilate, and ceases to supply
them with blood. These alternate motions of
contraction and dilatation of the heart and arte-
ries, are distinguished by the names systole and
diastole. When the heart is in a state of con-
traction or systole, the arteries are at that instant
distended with blood, and in their diastole; and
it 

365
PART IV. OF THE THORAX.
it is in this state we feel their pulsatory motion,
which we call the pulse. When the heart dilates,
and the arteries contract, the blood is impelled
onwards into the veins, through which it is re-
turned back to the heart. While the heart, how-
ever, is in its systole, the blood cannot pass from
the veins into the ventricles, but is detained in
the auricles, which are two reservoirs formed
for this use, till the diastole, or dilatation of the
heart, takes place; and then the distended au-
ricles contract, and drive the blood into the ven-
tricles: so that the auricles have an alternate sys-
tole and diastole as well as the heart.
Although both the ventricles of the heart con-
tract at the same time, yet the blood passes from
one to the other. In the same moment, for in-
stance, that the left ventricle drives the blood
into the aorta, the right ventricle impels it into
pulmonary artery, which is distributed through
all the substance of the lungs. The blood is
afterwards brought back into the left ventricle by
the pulmonary vein, at the same time that the
blood is returned by the cavas, into the right
ventricle, from all the other parts of the body.
This seems to be the mode of action of the
heart and its vessels: but the cause of this action
has, like all other intricate and interesting sub-
jects, been differently explained. It seems to
depend on the stimulus made on the different
parts of the heart by the blood itself, which by
its

366 
PART IV. OF THE THORAX.  
its quantity and heat, or other properties (D), is
perhaps capable of first exciting that motion,
which is afterwards continued through life, in-
dependent of the will, by a regular return of
blood to the auricles, in a quantity proportion-
ed to that which is thrown into the arteries.
The heart possesses the vis insita, or principle
of irritability, in a much greater degree than any
other muscle of the body. The pulse is quicker
in young than in old subjects, because the former
are cæt. par. more irritable than the latter. Up-
on the same principle we may explain, why the
pulse is constantly quicker in weak than in ro-
bust persons.
SECT. XIII. Of the Circulation.
After what has been observed of the struc-
ture and action of the heart and its auricles, and
likewise of the arteries and veins, there seem to
be but very few arguments required to demon-
strate the circulation of the blood, which has long
since been established as a medical truth. This
circulation may be defined to be a perpetual mo-
tion of the blood, in consequence of the action
of
(D) Dr. Harvey long ago suggested, that the blood is pos-
sessed of a living principle; and Mr. J. Hunter has lately en-
deavoured to revive this doctrine; in support of which he
has adduced many ingenious arguments. The subject is a
curious one, and deserves to be prosecuted as an inquiry
which cannot but be interesting to physiologists.

367
PART IV. OF THE THORAX.
of the heart and arteries, which impel it
through all the parts of the body, from whence
it is brought back by the veins of the heart. 
A very satisfactory proof of this circulation,
and a proof easy to be understood may be de-
ducted from the different effects of pressure on
an artery and a vein. If a ligature, for instance,
is passed round an artery, the vessel swells con-
siderably between the ligature and the heart;
whereas, if we tie up a vein, it only becomes
filled between the extremity and the ligature,
and this is what we every day observe in bleed-
ing. The ligature we pass round the arm on
these occasions, compresses the superficial veins;
and the return of the blood through them be-
ing impeded, they become distended. When
the ligature is too loose, the veins are not suffi-
ciently compressed, and the blood continues its
progress towards the heart; and, on the con-
trary, when it is made too tight, the arteries
themselves becomes compressed : and the flow of
the blood through them being impeded, the
veins cannot be distended.
Another phænomenon, which effectually
proves the circulation, is the loss of blood that
every living animal sustains by opening only a
single artery of a moderate size; for it continues
to flow from the wounded vessel till the equili-
brium is destroyed which is essential to life. This
truth was not unknown to the ancients; and it
seems, strange that it did not lead them to a
knowledge 

368 
PART IV. OF THE THORAX.  
knowledge of the circulation, as it sufficiently
proves, that all the other vessels must communi-
cate with that which is opened. Galen, who
lived more than 1500 years ago, drew this con-
clusion from it; and if we farther observe, that
he describes (after Erasistratus, who flourished
about 450 years before him) the several valves
of the heart, and determines their disposition
and uses, it will appear wonderful, that a pe-
riod of near 200 years should afterwards elapse
before the true course of the blood was ascertain-
ed. This discovery, for which we are indebt-
ed to the immortal Harvey, has thrown new
lights on physiology and the doctrine of dis-
eases, and constitutes one of the most impor-
tant periods of anatomical history.
SECT. XIV. Of the Nature of the Blood.
BLOOD, recently drawn from a vein into a
bason, would seem to be an homogeneous fluid
of a red colour (E); but when suffered to rest,
it soon coagulates, and divides into two parts,
which are distinguished by the names of crassa-
mentum and serum. The crassamentum is the
red coagulum, and the serum is the water in
which it floats. Each of these may be again se-
parated into two others; for the crassamentum,
by
(E) The blood, as it flows through the arteries, is ob-
served to be more florid than it is in the veins; and this red-
ness is acquired in its passage through the lungs. Vid. sect. vii.

369
PART IV. OF THE THORAX.
by being repeatedly washed in warm water, gives
out all its red globules, and what remains ap-
pears to be composed of the coagulable lymph (F),
which is a gelatinous substance, capable of being
hardened by fire till it becomes perfectly horny:
and if we expose the serum to a certain degree
of heat, part of it will be found to coagulate
like the white of an egg, and there will remain
a clear and lympid water, resembling urine both
in its appearance and smell.
The serum and crassamentum differ in their
proportion in different constitutions; in a strong
person, the crassamentum is in a greater pro-
portion to the serum than in a weak one;* and
the same difference is found to take place in dis-
eases (G).
Aa SECT. XV.
(F) It may not be improper to observe, that till of late the
coagalable lymph has been confounded with the serum of the
blood, which contains a substance that is likewise coagula-
ble, though only when exposed to heat, or combined with
certain chemical substances; whereas the other coagulates
spontaneously when exposed to the air or to rest.
* Hewson's Experim. Enq. Part. I. 
(G) When the blood separates into serum and crassamen-
tum, if the latter be covered with a crust of a whitish or
buff colour, it, has been usually considered as a certain
proof of the blood's being in a state of too great viscidity.
This appearance commonly taking place in inflammatory
diseases, has long served to confirm the theory which ascribes
the cause of inflammation to lentor and obstrudsions. But
from the late Mr. Hewson's experiments it appears, that
when the action of the arteries is increased, the blood, in-
stead of being more viscid, is, on the conrtary, more fluid
than 

370 
PART IV. OF THE THORAX. 
SECT. XV. Of Nutrition.
THE variety of functions which we have de-
scribed as being incessantly performed by the liv-
ing body, and the continual circulation of the
blood through it, must necessarily occasion a
constant dissipation of the several parts which
enter into its composition. In speaking of the
insensible perspiration, we observed how much
was incessantly passing off from the lungs and
the surface of the skin. The discharge by urine
is likewise every day considerable; and great
part of the bile, saliva, &c. are excluded by
stool. But the solid, as well as the fluid parts
of the body, require a constant renewal of nu-
tritious particles. They are exposed to the at-
trition of the fluids which are circulated through
them; and the contraction and relaxation they
repeat so many thousand times in every day,
would necessarily occasion a dissolution of the
machine, if the renewal was not proportioned
to the waste.
It is easy to conceive how the chyle formed
from the aliment is assimilated into the nature of
the
than in the ordinary state, previous to inflammation : and
that in consequence of this, the coagulable lymph suffers
the red globules, which are the heaviest part of the blood,
to fall down to the bottom before it coagulates : so that
the crassamentum is divided into two parts; one of which
is found to consist of the coagulable lymph alone (in this case
termed the buff;) and the other, partly of this and partly
of the red globules. 

371
PART IV. OF THE THORAX.
the blood, and repairs the loss of the fluid parts
of our body; but how the solids are renewed,
has never yet been satisfactorily explained. The
nutritious parts of the blood are probably de-
posited by the arteries by exsudation through
their pores into the tela cellulosa; and as the
solid parts of the body are in the embryo only
a kind of jelly, which gradually acquires the
degree of consistence they are found to have
when the body arrives at a more advanced age;
and these same parts which consist of bones,
cartilages, ligaments, muscles, &c. are some-
times reduced again by diseases to a gelati-
nous state; we may, with some degree of pro-
bability, consider the coagulable lymph as the
source of nutrition.
If the supply of nourishment exceeds the de-
gree of waste, the body increases; and this hap-
pens in infancy and in youth: for at those peri-
ods, but more particularly the former one, the
fluids bear a large proportion to the solids; and
the fibres being soft and yielding, are proporti-
onably more capable of extension and increase.
But when the supply of nutrition only equals
the waste, we neither increase or decrease; and
we find this to be the case when the body has
attained its full growth or acme: for the solids
having then acquired a certain degree of firm-
ness and rigidity do not permit a farther in-
crease of the body. But as we approach to old
age, rigidity begins to be in excess, and the
Aa2 fluids 


372 
PART IV. OF THE THORAX.  
fluids (H) bear a much less proportion to the so-
lids than before. The dissipation of the body
is greater than the supply of nourishment; many
of the smaller vessels become gradually imper-
vious (I); and the fibres losing their moisture
and their elasticity, appear flaccid and wrinkled.
The lilies and the roses disappear, because the fluids
by which they were produced can no longer reach
the extremities of the capillary vessels of the skin.
As these changes take place, the nervous power
being proportionably weakened, the irritability
and sensibility of the body, which were formerly
so remarkable, are greatly diminished; and in
advanced life, the hearing, the eye-sight, and
all the other senses, become gradually impaired.
SECT. XVI. Of the Glands and Secretions.
THE glands are commonly understood to be
small, roundish, or oval bodies formed by the
convolution of a great number of vessels, and
destined to separate particular humours from the
mass of blood.
They are usually divided into two classes; but
it
(H) As the fluids become less in proportion to the solids,
their acrimony is found to increase; and this may perhaps
compensate for the want of fluidity in the blood, by dimi-
nishing its cohesion.
(I) In infancy, the arteries are numerous and large in
respect to the veins, and the lymphatic glands are larger
than at any other time of life; whereas, in old age, the ca-
pacity of the venous system exceeds that of the arteries, and
the lymphatic system almost disappears. 

373
PART IV. OF THE THORAX.
it seems more proper to distinguish three kinds
of glands, viz. the mucous, conglobate, and con-
glomerate.
The mucous glands, or follicles, as they are most
commonly called, are small cylindrical tubes
continued from the ends of arteries. In some
parts of the body, as in the tonsils, for example,
several of these follicles may be seen folded to-
gether in one common covering, and opening
into one common sinus. These follicles are the
vessels that secrete and pour out mucus in the
mouth, œsophagus, stomach, intestines, and other
parts of the body.
The conglobate glands are peculiar to the lym-
phatic system. Every lymphatic vein passes
through a gland of this kind in its way to the
thoracic duct. They are met with in different
parts of the body, particularly in the axilla, groin,
and mesentery, and are either solitary or in distinct
clusters.
The conglomerate glands are of much greater
bulk than the conglobate, and seem to be an as-
semblage of many smaller glands. Of this kind
are the liver, kidneys, &c. Some of them, as
the pancreas, parotids, &c. have a granulated ap-
pearance. All these conglomerate glands are
plentifully supplied with blood-vessels; but their
nerves are in general very minute, and few in
number. Each little granulated portion fur-
nishes a small tube, which unites with other si-
milar

374 
PART IV. OF THE THORAX.  
milar ducts, to form the common excretory duct
of the gland.
The principal glands, and the humours they
secrete, have been already described in different
parts of this work; and there only remains for
us to examine the general structure of the glands,
and to explain the mechanism of secretion. On
the first of these subjects two different systems
have been formed; each of which has had, and
still continues to have, its adherents. One of
these systems was advanced by Malpighi, who
supposed that an artery entering into a gland ra-
mifies very minutely through its whole substance;
and that its branches ultimately terminate in a
vesicular cavity or follicle, from whence the se-
creted fluid passes out through the excretory duct.
This doctrine at first met with few opponents;
but the celebrated Ruysch, who first attempted
minute injections with wax, afterwards disputed
the existence of these follicles, and asserted, that
every gland appears to be a continued series of
vessels, which after being repeatedly convoluted
in their course through its substance, at length
terminate in the excretory duct. Anatomists
are still divided between these two systems : that
of Malpighi, however; seems to be the best
founded.
The mode of secretion has been explained in
a variety of ways, and they are all perfectly hy-
pothetical. In such an inquiry it is natural to
ask, how one gland constantly separates a parti-
cular 

375
PART IV. OF THE THORAX.
cular humour, while another gland secretes one
of a very different nature from the blood? The
bile, for instance, is separated by the liver, and
the urine by the kidneys. Are these secretions
to be imputed to any particular dispositions in
the fluids, or is their cause to be looked for in
the solids?
It has been supposed, that every gland con-
tains within itself a fermenting principle, by
which it is enabled to change the nature of the
blood it receives, and to endue it with a particu-
lar property. So that, according to this system,
the blood, as it circulates through the kidneys,
becomes mixed with the fermenting principle of
those glands, and a part of it is converted into
urine; and again, in the liver, in the salival and
other glands, the bile, the saliva, and other
juices, are generated from a similar cause. But
it seems to be impossible for any liquor to be con-
fined in a place exposed to the circulation, with-
out being carried away by the torrent of blood,
every part of which would be equally affected;
and this system of fermentation has long been
rejected as vague and chimerical. But as the
cause of secretion continued to be looked for in
the fluids, the former system was succeeded by
another, in which recourse was had to the ana-
logy of the humours. It was observed, that if
paper is moistened with water, and oil and wa-
ter are afterwards poured upon it, that the water
only will be permitted to pass through it; but
that, 

376 
PART IV. OF THE THORAX. 
that, on the other hand, if the paper has been
previously soaked in oil instead of water, the oil
only, and not the water, will be filtered through
it. These observations led to a supposition, that
every secretory organ is originally furnished with
a humour analogous to that which it is after-
wards destined to separate from the blood; and
that in consequence of this disposition, the secre-
tory vessels of the liver, for instance, will only
admit the bilous particles of the blood, while all
the other humours will be excluded. This sys-
tem is an ingenious one, but the difficulties with
which it abounds are unanswerable; for oil and
water are immiscible; whereas the blood, as it
is circulated through the body, appears to be an
homogeneous fluid. Every oil will pass through
a paper moistened only with one kind of oil;
and wine, or spirits mixed with water, will easily
be filtered through a paper previously soaked in
water. Upon the same principle, all our humours,
though differing in their other properties, yet
agreeing in that of being perfectly miscible with
each other, will all easily pass through the same filtre.
But these are not all the objections to this system.
The humours which are supposed to be placed in
the secretory vessels for the determination of simi-
lar particles of the blood, must be originally se-
parated without any analogous fluid; and that
which happens once, may as easily happen al-
ways. Again, it sometimes happens from a vi-
cious disposition, that humours are filtered
through glands which are naturally not intended
to

377
PART IV. OF THE THORAX.
to afford them a passage; and when this once
has happened, it ought, according to this system,
to be expected always to do so : whereas this is
not the case; and we are, after all, naturally led
to seek for the cause of secretions in the solids.
It does not seem right to ascribe it to any parti-
cular figure of the excretory vessels; because the
soft texture of those parts does not permit them
to preserve any constant shape, and our fluids
seem to be capable of accommodating themselves
to every kind of figure, Some have imputed
it to the difference of diameter in the orifices of
the different secretory vessels. To this doctrine
objections have likewise been raised; and it has
been argued, that the vessels of the liver, for in-
stance, would, upon this principle, afford a pas-
sage not only to the bile, but to all the other hu-
mours of less consistence with it. In reply to
this objection, it has been supposed, that secon-
dary vessels exist, which originate from the first,
and permit all the humours thinner than the bile
to pass through them.
Each of these hypotheses is probably very re-
mote from the truth.
EXPLANATION OF PLATE XXVIII.
This plate represents the Heart in situ, all
the large Arteries and Veins, with some of the
Muscles, &c.
Muscles, &c.—SUPERIOR EXTREMITY.—
a, Masseter. b, Complexus. C, Digastricus.
d, Os 

378 
PART IV. OF THE THORAX.  
d, Os hyoides. e, Thyroid gland. f, Levator
scapulæ. g, Cucullaris. h h, The clavicles cut.
i, The deltoid muscle. k, Biceps flexor cubiti
cut. l, Caraco-brachialis. m, Triceps exten-
sor cubiti. n, The heads of the pronator teres,
flexor carpi radiales, and flexor digitorum sub-
limis, cut. o, The flexor carpi ulnaris, cut at
its exteremity. p, Flexor digitorum profundus.
q, Supinator radii longus, cut at its extremity.
r, Ligamentum carpi transversale. s, Extensores
carpi radiales. t, Latissimus dorsi. u, Anterior
edge of the serratus anticus major, vv, The in-
ferior part of the diaphragm. w w, Its anterior
edge cut. xx, The kidneys. y, Transversus
abdominis. z, Os ilium.
INFERIOR EXTREMITY. a, Psoas magnus.
b, Iliacus internus. c, The fleshy origin of the
tensor vagina femoris. dd, The ossa pubis cut
from each other. e, Musculus pectineus cut
from its origin. f, Short head of the triceps ab-
ductor femoris cut. g, The great head of the
triceps. h, The long head cut. i, Vastus in-
turnus. k, Vastus externus. l, Crureus. m,
Gemellus. n, Soleus. o, Tibia. p, Peronæus
longus. q, Peronæus brevis. r, Fibula.
HEART and BLOOD-VESSELS.—A, The heart,
with the coronary arteries and veins. B, The
right auricle of the heart. C, The aorta ascen-
dens. D, The left subclavian artery. E, The
left carotid artery. F, The common trunk which
sends off the right subclavian and right carotid
arteries. 

ANATOMY 
PLATE XXVIII

 

379
PART IV. OF THE THORAX.
arteries. G, The carotis externa. H, Arteria
facialis, which sends off the coronary arteries of
the lips. I. Arteria temporalis profunda. K,
Aorta descendens. LL, The iliac arteries,—
which send off MM, The femoral or crural ar-
teries. N. B. The other arteries in this figure
have the same distribution as the veins of the
same name:—And generally, in the anatomi-
cal plates, the description to be found on the one
side, points out the same parts in the other. 1,
The frontal vein. 2, The facial vein. 3, Vena
temporalis profunda. 4, Vena occipitalis. 5,
Vena jugularis externa. 6, Vena jugularis in-
terna, covering the arteria carotis communis. 7,
The vascular arch on the palm of the hand, which
is formed by, 8, The radial artery and vein, and,
9, The ulnar artery and vein. 10 10, Cephalic
vein. 11, Basilic vein, that on the right side
cut. 12, Median vein. 13, The humeral vein,
which, with the median, covers the humeral ar-
tery. 14 14, The external thoracic or mam-
mary arteries and veins. 15, The axillary vein,
covering the artery. 1616, The subclavian
veins, which, with (66) the jugulars, form, 17,
The vena cava superior. 18, The cutaneous
arch of veins on the fore part of the foot. 19,
The vena tibialis antica, covering the artery. 20,
The vena profunda femoris, covering the artery.
21, The upper part of the vena saphena major.
22, The femoral vein. 2323, The iliac veins.
24 24, Vena cava inferior. 2525, The renal
veins covering the arteries. 2626, The dia-
phragmatic veins. 
PART V.

380 
Part V. OF THE BRAIN.
PART V.
OF THE BRAIN AND NERVES.
SECT. I. Of the Brain and its Integuments.
THE bones of the cranium were described
in the osteological part of this work, as in-
closing the brain, and defending it from external
injury: but they are not its only protection; for
when we make an horizontal section through
these bones, we find this mass every where sur-
rounded by two membranes (K), the dura and
pia mater.—The first of these lines the interior
surface of the cranium, to which it every where
adheres strongly (L), but more particularly at the
sutures, and at the many foramina through which
vessels pass between it and the pericranium. The
dura
(K) The Greeks called these membranes meninges; but
the Arabians, supposing them to be the source of all the
other membranes of the body, afterwards gave them the
names of dura and pia mater; by which they are now usu-
ally distinguished.
(L) In young subjects this adhesion is greater than in
adults; but even then, in the healthy subject, it is no where
easily separated, without breaking through some of the mi-
nute vessels by means of which it is attached to the bone. 

381
PART V. AND NERVES.
dura mater (M) is perfectly smooth and inelastic,
and its inner surface is constantly bedewed with
a fine pellucid fluid, which every where separates
it from the pia mater. The dura mater sends off
several considerable processes, which divide the
brain into separate portions, and prevent them
from compressing each other. Of these processes
there is one superior and longitudinal, called the
falx, or falciform process, from its resemblance
to a scythe. It arises from the spine of the os
frontis, near the christa galli, and extending along
in the direction of the sagittal suture, to beyond
the lambdoidal suture, divides the brain into two
hemispheres. A little below the lambdoidal su-
ture, it divides into two broad wings or expan-
sions called the transverse or lateral processes,
which prevents the lobes of the cerebrum from
pressing on the cerebellum. Besides these there
is a fourth, which is situated under the trans-
verse processes, and being continued to the spine
of the occiput, divides the cerebellum into two
lobes.
The
(M) This membrane is commonly described as consisting
of two laminæ ; of which the external one is supposed to
perform the office of periosteum internum to the cranium,
while the internal one forms the folds and processes of the
dura mater. In the natural state, however, no such separa-
tion is apparent; like other membranes, we may indeed di-
vide it, not into two only, but many laminæ; but this divi-
sion is artificial, and depends on the dexterity of the ana-
tomist.

382 
PART V. OF THE BRAIN. 
The blood, after being distributed through
the cavity of the cranium by means of the ar-
teries, is returned, as in, the other parts of the
body, by veins which all pass on to, certain chan-
nels, situated behind these several processes.
These canals or sinuses communicate with each
other, and empty themselves into the internal
jugular veins, which convey the blood into the
vena cava. They are in fact triangular veins,
running through the substance of the dura mater,
and, like the processes, are distinguished into
longitudinal and lateral; and where these three
meet, and where the fourth process passes off, we
observe a fourth sinus, which is called torcular;
Herophilus, who first described it, having sup-
posed that the blood at the union of these two
veins, is, as it were, in a press.
Besides these four canals, which were known
to the ancients, modern anatomists enumerate
many others, by giving the appellation of sinuses
to other veins of the dura mater, which for the
most part empty themselves into some of those
we have just now described. There are the in-
ferior longitudinal sinus, the superior and inferior
petrous sinuses, the cavernous sinuses, the circu-
lar sinus, and the anterior and posterior occipital
sinuses.
These sinuses or veins, by being conveyed
through a thick dense membrane, firmly suspend-
ed, as the dura mater is, within the cranium,
are less liable to rupture; at the same time they
3 are


383
PART. V. AND NERVES.
are well supported, and by running every where
along the inner surface of the bones, they are
prevented from pressing on the substance of the
brain. To prevent too great a dilatation of them,
we find filaments (called chordæ Willisii, from
their having been first noticed by Willis) stretch-
ed across their cavities; and the oblique manner
in which the veins from the brain run through
the substance of the brain into these channels,
serves the purpose of a valve, which prevents
the blood from turning back into the smaller and
weaker vessels of the brain.
The pia mater is a much softer and finer mem-
brane than the dura mater; being exceedingly
delicate, transparent, and vascular. It invests
every part of the brain, and sends off an infinite
number of elongations, which insinuate them-
selves between the convolutions, and even into
the substance of the brain. This membrane is
composed of two laminæ; of which the exterior
one is named tunica arachnoidea, from its thin-
ness, which is equal to that of a spider's web.
These two laminæ are intimately adherent to each
other at the upper part of the brain, but are easily
separable at the basis of the brain, and through
the whole length of the medulla spinalis. The
external layer, or tunica arachnoidea, appears to
be spread uniformly over the surface of the brain,
but without entering into its furrows as the in-
ner layer does; the latter being found to insinu-
ate itself between the convolutions, and even into
the

384 
PART V. OF THE BRAIN.
the interior cavities of the brain. The blood-
vessels of the brain are distributed through it in
their way to that organ, and are therefore divided
into very minute ramifications, before they pene-
trate the substance of the brain.
There are several parts included under the ge-
neral denomination of brain. One of these,
which is of the softest consistence, and fills the
greatest part of the cavity of the cranium, is the
cerebrum, or brain properly so called. Another
portion, which is seated in the inferior and pos-
terior part of the head, is the cerebellum; and a
third, which derives its origin from both these,
is the medulla oblongata.
The cerebrum is a medullary mass of a mode-
rate consistence, filling up exactly all the upper
part of the cavity of the cranium, and divided
into two hemispheres by the falx of the dura
mater. Each of these hemispheres is usually dif-
tinguished into an interior, a middle, and a pos-
terior lobe. The first of these is lodged on the
orbital processes of the os frontis; the middle
lobes lie on the middle fossæ of the basis of the
cranium, and the posterior lobes are placed on
the transverse septum of the os occipitis, imme-
diately over the cerebellum, from which they are
separated by the lateral processes of the dura ma-
ter. These two portions afford no distinguishing
mark of separation; and on this account Haller,
and many other modern anatomists, omit the
distinction

385
PART V. AND NERVES.
distinction of middle lobe, and speak only of the
anterior and posterior lobes of the brain.
The cerebrum appears to be composed of two
distinct substances. Of these, the exterior one,
which is of a greyish or ash-colour, is called the
cortex, and is somewhat softer than the other,
which is very white, and is called medulla or sub-
stantia alba.
After having removed the falx, and separated
the two hemispheres from each other, we per-
ceive a white convex body, the corpus callosum,
which is a portion of the medullary substance,
uniting the two hemispheres to each other, and
not invested by the cortex. By making an ho-
rizontal incision in the brain, on a level with this
corpus callosum, we discover two oblong cavi-
ties, named the anterior or lateral ventricles, one
in each hemisphere. These two ventricles,
which communicate with each other by a hole
immediately under the plexus choroides, are se-
parated laterally by a very fine medullary parti-
tion, called septum lucidum, from its thinness and
transparency. The lower edge of this septum is
fixed to the fornix, which is a kind of medullary
arch (as its name implies) situated under the cor-
pus callosum, and nearly of a triangular shape.
Anteriorly the fornix sends off two medullary
chords, called its anterior crura; which seem to
be united to each other by a portion of medulla-
ry substance, named commissura anterior cerebri.
These crura diverging from one another, are lost
Bb at


386 
PART V. OF THE BRAIN.
at the other side of the lower and fore-part of the
third ventricle. Posteriorly the fornix is formed
into two other crura, which unite with two me-
dullary protuberances called pedes hippocampi,
and sometimes cornua ammonis, that extend along
the back-part of the lateral ventricles. The
concave edge of the pedes hippocampi is co-
vered by a medullary lamina, called corpus sim-
briatum.
Neither the edges of the fornix, nor its poste-
rior crura, can be well distinguished, till we have
removed the plexus choroides. This is a pro-
duction of the pia mater, which is spread over
the lateral ventricles. Its loose edges are collect-
ed, so as to appear like a vascular band on each
side.
When we have removed this plexus, we
discover several other protuberances included in
the lateral ventricles. These are the corpora
striata, the thalami nervorum opticorum, the
tubercula quadrugemina, and the pineal gland.
The corpora striata are two curved oblong emi-
nences, that extend along the anterior part of the
lateral ventricles. They derive their name from
their striated appearance, which is owing to an
intermixture of the cortical and medullary sub-
stances of the brain. The thalami nervorum op-
ticorum, are so called, because the optic nerves
arise chiefly from them, and they are likewise
composed both of the cortex and medulla. They
are separated from the corpora striata only by a
kind 

387
PART V. AND NERVES.
kind of medullary chord, the geminum centrum
semi-circulare. The thalami are nearly of an
oval shape, and are situated at the bottom of the
upper cavity of the lateral ventricles. They are
closely united, and at their convex part seem to
become one body.
Anteriorly, in the space between the thalami,
we observe an orifice by which the lateral ven-
tricles communicate, and another leads down
from this, under the different appellations of
foramen commune anterius, vulva iter ad infundi-
bulum, but more properly iter ad tertium ventri-
culum; and the separation of the thalami from
each other posteriorly, forms another opening or
interstice called anus. This has been supposed
to communicate with the third ventricle; but it
does not, the bottom of it being shut up by the
pia mater. The back part of the anus is formed
by a kind of medullary band, which connects the
thalami to each other, and is called commissura
posterior cerebri.
Behind the thalami and commissura posterior,
we observe a small, soft, greyish, and oval body,
about the size of a pea. This is the glandula pi-
nealis; it is described by Galen under the name
of conarion, and has been rendered famous by
Descartes, who supposed it to be the seat of the
soul. Galen seems formerly to have entertained
the same opinion. Some modern writers have,
with as little reason, imagined that the soul is
placed in the corpus callosum.
Bb2 The 
 

388 
PART V. OF THE BRAIN.
The pineal gland rests upon four remarkable
eminences, disposed in pairs, and seated imme-
diately below it. These tubercles, which by the
ancients were called testes and nates, have, since
the time of Winslow, been more commonly nam-
ed tubercula quadrugemina.
Under the thalami we observe another cavity,
the third ventricle, which terminates anteriorly
in a small medullary canal, the infundibulum,
that leads to the glandula pituitaria. It has been
doubted, whether the infundibulum is really hol-
low; but some late experiments on this part of
the brain * by Professor Murray of Upsal, dearly
prove it to be a medullary canal, surrounded by
both laminæ of the pia mater. After freezing
the brain, this channel was found filled with ice;
and de Haen tells † us, he found it dilated, and
filled with a calcareous matter (N).
The soft spongy body in which the infundibu-
lum terminates, was by the ancients supposed to
be of a glandular structure, and destined to filter
the serosity of the brain. Spigelius pretended
to have discovered its excretory duct, but it seems
certain that no such duct exists. It is of an
oblong
* Diso. de Infundibulo Cerebri.
† Ratio Med. tom. vi. p. 271.
(N) The under part of it, however, appears to be imper-
vious; at least no injection that can be depended on has been
made to pass from it into the glandula pitoitaria without lace-
ration of parts. 

389
PART V. AND NERVES.
oblong shape, composed, as it were, of two
lobes. In ruminant animals it is much larger
than in man.
From the posterior part of the third ven-
tricle, we see a small groove or channel, de-
scending obliquely backwards. This channel,
which is called the aqueduct of Sylvius, though it
was known to the ancients, opens into another
cavity of the brain, placed between the cerebel-
lum and medulla oblongata, and called the fourth
ventricle.
The cerebellum, which is divided into two
lobes, is commonly supposed to be of a firmer
texture than the cerebrum; but the truth is,
that in the greater number of subjects, there ap-
pears to be no sensible difference in the con-
sistence of these two parts. It has more of the
cortical than of the medullary substance in its
composition.
The furrow that divides the two lobes of the
cerebellum leads anteriorly to a process, compos-
ed of medullary and cortical substances, covered
by the pia mater; and which, from its being di-
vided into numerous furrows, resembling the
rings of the earth-worm, is named processus ver-
miformis. This process forms a kind of ring in
its course between the lobes.
The surface of the cerebellum does not af-
ford those circumvolutions which appear in the
cerebrum; but instead of these, we observe a
great number of minute furrows, running pa-
rallel

390 
PART V. OF THE BRAIN.
rallel to each other, and nearly in a transverse di-
rection. The pia mater insinuates itself into
these furrows.
When we cut into the substance of the cere-
bellum, from above downwards, we find the
medullary part running in a kind of ramifying
course, and exhibiting an appearance that has
gotten the name of arbor vitæ. These ramifi-
cations unite to form a medullary trunk; the
the middle, anterior, and most considerable part
of which forms two processes, the crura cerebel-
li, which unite with the crura cerebri, to form
the medulla oblongata. The last furnishes two
other processes, which lose themselves under the
nates, and thus unite the lobes of the cerebellum
to the posterior part of the cerebrum. Under
the nates we observe a transverse medullary line,
or linea alba, running from one of these processes
to the other; and between them we find a very
thin medullary lamina, covered with the pia ma-
ter, which the generality of anatomists have
(though seemingly without reason) considered
as a valve formed for closing the communica-
tion between the fourth ventricle and the aquæ-
ductus Sylvii. Vieussens named it valvula ma-
jor cerebri.
The medulla oblongata is situated in the mid-
dle, lower, and posterior part of the cranium,
and may be considered as a production or con-
tinuation of the whole medullary substance of
the cerebrum and cerebellum, being formed by
the

391
PART V. AND NERVES.
the of two considerable medullary processes of
the cerebrum, called crura cerebri, with two
other smaller ones from the cerebellum, which
were just now spoken of under the name or
crura cerebelli.
The crura cerebri arise from the middle and
lower part of each hemisphere. They are sepa-
rated from each other at their origin, but are
united below, where they terminate in a middle
protuberance, the pons Varolii, so called, because
Varolius compared it to a bridge. This name,
however, can convey no idea of its real appear-
ance. It is, in fact, nothing more than a me-
dullary protuberance, nearly of a semi-spherical
shape, which unites the crura cerebri to those of
the cerebellum.
Between the crura cerebri, and near the ante-
rior edge of the pons Varolii, are two tubercles,
composed externally of medullary, and internal-
ly of cineritious substance, to which Eustachius
first gave the name of eminentiæ mamillares.
Along the middle of the posterior surface of
the medulla oblongata, where it forms the ante-
rior part of the fourth ventricle, we observe a
kind of furrow which runs downwards and ter-
minates in a point. About an inch above the
lower extremity of this fissure, several medullary
filaments are to be seen running towards it on
each side in an oblique direction, so as to give
it the appearance of a writing-pen; hence it is
called calamus scriptorius.
From

392 
PART V. OF THE BRAIN.  
From the posterior part of the pons Varolii,
the medulla oblongata descends obliquely back-
wards ; at its fore-part, immediately behind the
pons Varolii, we observe two pair of eminences,
which were described by Eustachius, but receiv-
ed no particular appellation till the time of Vi-
eussens, who gave them the names of corpora
olivaria and corpora pyramidalia. The former
are the outermost, being placed one on each side.
They are nearly of an oval shape, and are com-
posed of medulla, with streaks of cortical sub-
stance. Between these are the corpora pyra-
midalia, each of which terminates in a point.
In the human subject these four eminences are
sometimes not easily distinguished.
The medulla spinalis, or spinal marrow, which
is the name given to the medullary chord that
is extended down the vertebral canal, from the
great foramen of the occipital bone to the bot-
tom of the last lumbar vertebra, is a continua-
tion of the medulla oblongata. Like the other
parts of the brain, it is invested by the dura and
pia mater. The first of these, in its passage out
of the cranium, adheres to the foramen of the
os occipitis. Its connection with the ligamentary
substance that lines the cavity of the spine, is on-
ly by means of cellular membrane; but between
the several vertebræ, where the nerves pass out
of the spine, it sends off prolongations, which
adhere strongly to the vertebral ligaments. Here,
as in the cranium, the dura mater has its sinuses
or 

393
PART V. AND NERVES.
or large veins. These are two in number, and
are seen running on each side of the medullary
column, from the foramen magnum of the os
occipitis to the lower part of the os sacrum. They
communicate together by ramifying branches at
each vertebra, and terminate in the vertebral,
intercostal, and sacral veins.
The pia mater is connected with the dura ma-
ter by means of a thin transparent substance,
which from its indentations between the spinal
nerves has obtained the name of ligamentum den-
ticulatum. It is somewhat firmer than the tu-
nica arachnoidea, but in other respects resem-
bles that membrane. Its use is to support the spi-
nal marrow, that it may not affect the medulla
oblongata by its weight.
The spinal marrow itself is externally of a
white colour; but upon cutting into it we find
its middle-part composed of a darker coloured
mass, resembling the cortex of the brain. When
the marrow has reached the first lumbar verte-
bra, it becomes extremely narrow, and at length
terminates in an oblong protuberance; from the
extremity of which the pia mater sends off a
prolongation or ligament, resembling a nerve,
that perforates the dura mater, and is fixed to
the os coccygis.
The medulla spinalis gives rise to 30 or 31
pair of nerves, but they are not all of the same
size, nor do they all run into in the same direc-
tion. The upper ones are thinner than the rest,
and 

394 
PART V. OF THE BRAIN ..
and are placed almost transversely: as we descend
we find them running more and more obliquely
downwards, till at length their course is almost
perpendicular, so that the lowermost nerves ex-
hibit an appearance that is called cauda equina,
from its resemblance to a horse's tail.
The arteries that ramify through the different
parts of the brain, are derived from the inter-
nal carotid and from the vertebral arteries. The
medulla spinalis is supplied by the anterior and
posterior spinal arteries, and likewise receives
branches, from the cervical, the inferior and su-
perior intercostal, the lumbar, and the sacral ar-
teries.
SECT. II. Of the Nerves.
THE nerves are medullary chords, differing
from each other in size, colour, and consistence,
and deriving their origin from the medulla ob-
longata and medulla spinalis. There are 39, and
sometimes 40, pair of these nerves; nine (O) of
which originate from the medulla oblongata, and
30 or 31 from the medulla spinalis. They ap-
pear to be perfectly inelastic, and likewise to pos-
sess
(O) It has been usual to describe the ten pair of nerves as
arising from the medulla oblongata; but as the tenth pair
arise in the same manner as the other spinal nerves, Santorini,
Heister, Haller, and others, seem very properly to have
classed them among the nerves of the spine. 

395
PART V. AND NERVES.
sess no irritability. If we irritate muscular fi-
bres, they immediately contract; but nothing
of this sort happens if we irritate a nerve. They
carry with them a covering from the pia mater;
but derive no tunic from the dura mater, as hath
been generally, though erroneously, supposed,
ever since the time of Galen (P), the outer cover-
ing of the nerves being in fact nothing more
than the cellular membrane. This covering is
very thick where the nerve is exposed to the
action of muscles; but where it runs through a
bony canal, or is secure from pressure, the cel-
lular tunic is extremely thin, or altogether want-
ing. We have instances of this in the portio
mollis of the auditory nerve, and in the nerves
of the heart. 
By elevating, carefully and gently, the brain
from the basis of the cranium, we find the first
nine pair arising in the following order: 1. The
nervi olfactorii, distributed through the pituita-
ry membrane, which constitutes the organ of
smell. 2. The optici, which go to the eyes, where
they receive the impressions of visible objects.
3. The oculorum motores, so called because they
are distributed to the muscles of the eye. 4.
The
(P) Baron Haller and Professor Zinn seem to have been
the first who demonstrated, that the dura mater is reflected
upon and adheres to the periosteum at the edges of the fora-
mina that afford a passage to the nerves out of the cranium,
and vertebral canal, or is soon lost in the cellular substance, 

396 
PART V. OF THE BRAIN.
The pathetici, distributed to the superior oblique
muscles of the eyes, the motion of which is
expressive of certain passions of the soul. 5. The
nerves of this pair soon divide into three prin-
cipal branches, and each of these has a different
name. Its upper division its he ophthalmicus,
which is distributed to various parts of the
eyes, eye-lids, forehead, nose, and integu-
ments of the face. The second is called the
maxillaris superior, and the third maxillaris in-
ferior; both of which names allude to their dis-
tribution. 6. The abductores; each of these
nerves is distributed to the abductor muscle of
the eye, so called, because it helps to draw the
globe of the eye, from the nose. 7. The
auditorii (Q), which are distributed through
the organs of hearing. 8. The par vagum,
which derives its name from the great number of
parts to which it gives branches both in the tho-
rax and abdomen. 9. The linguales, or hypo-
glossi, which are distributed to the tongue, and
appear
(Q) This pair, soon after its entrance into the meatus audi-
torius internus, separates into two branches. One of these 
is of a very soft and pulpy consistence, it is called the portio
mollis of the seventh pair, and is spread over the inner part
of the ear. The other passes out through the aqueduct of
Fallopius in a firm chord, which is distinguished as the por-
tio dura, and is distributed to the external ear and other
parts of the neck and face.

397
PART V. AND NERVES.
appear to contribute both to the organ of taste
and to the motions of the tongue (R).
It has already been observed, that the spinal
marrow sends off 30 or 31 pair of nerves; these
are chiefly distributed to the exterior parts of the
trunk and to the extremities. They are com-
monly distinguished into the cervical, dorsal,
lumbar, and sacral nerves. The cervical, which
pass out from between the several vertebræ of
the neck, are eight (S) in number; the dorsal,
twelve; the lumbar five; and the sacral, five or
six; the number of the latter depending on the
number of holes in the os sacrum. Each spinal
nerve at its origin is composed of two fasciculi of
medullary fibres. One of these fasciculi arises
from the anterior, and the other from the pos-
terior surface of the medulla. These fasciculi
are
(R) Heister has summed up the uses of these nine pair of
nerves in the two following Latin verses :
"Olfaciens, cernens, oculosque novens, patiensque,
"Gastans, abducens, audiensque, vagansque, loquensque."
(S) Besides these, there is another pair called accessorii, which
arises from the medulla spinalis at its beginning; and ascending
the great foramen of the os occipitis into the cranium, passes
out again close to the eighth pair, with which, however, it
does not unite; and it is afterwards distributed chiefly to the
muscles of the neck, back, and scapula. In this course it sends
off filaments to different parts, and likewise communicates with
several other nerves. Physiologists are at a loss how to account
for the singular origin and course of these nervi accessorii. The
indents considered them as a branches of the eighth pair, dis-
tributed to muscles of the scapula: Willis likewise considered
them as appendages to that pair, and on that account named
them accessorii. They are sometimes called the spinal pair;
but as this latter name is applicable to all the nerves of the spine
indiscriminately, it seems better to adapt that given by Willis.

398 
PART V. OF THE BRAIN.
are separated by the ligamentum denticulatum;
after which we find them contiguous to one ano-
ther. They then perforate the dura mater, and
unite to form a considerable knot or ganglion.
Each of these ganglions sends off two branches;
one anterior, and the other posterior. The an-
terior branches communicate with each other at
their coming out of the spine, and likewise send
off one, and sometimes more branches, to assist
in the formation of the intercostal nerve.
The knots or ganglions of the nerves just
now spoken of, are not only to be met with at
their exit from the spine, but likewise in various
parts of the body. They occur in nerves of
the medulla oblongata, as well as in those
of the spine. They are not the effects of dis-
ease, but are to be met with in the same parts
of the same nerves, both in the fœtus and adult.
They are commonly of an oblong shape, and
of a greyish colour, somewhat inclined to red,
which is perhaps owing to their being extreme-
ly vascular. Internally we are able to distinguish
something like an intermixture of the nervous
filaments.
Some writers have considered them as so ma-
ny little brains; Lancisi fancied he had disco-
vered muscular fibres in them, but they are cer-
tainly not of an irritable nature. A late writer,
Dr. Johnstone*, imagines they are intended to
deprive us of the power of the will over cer-
tain
* Essay on the Use of the Ganglions of the Nerves.

399
PART V. AND NERVES.
tain parts, as the heart, for instance: but if this
hypothesis were well founded, we should meet
with them only in the nerves leading to involun-
tary muscles; whereas it is certain, that the vo-
luntary muscles receive their nerves through gan-
glions. Doctor Monro, from observing the ac-
curate intermixture of the minute nerves which
compose them, considers them as new sources of
nervous energy †.
The nerves, like the blood-vessels, in their
course through the body, communicate with
each other; and each of these communications
constitutes what is called a plexus, from whence
branches are again detached to different parts of
the body. Some of these are constant and con-
siderable enongh to be distinguished by particu-
lar names, as the semilunar plexus; the pulmo-
nary plexus; the hepatic, the cardiac, &c.
It would be foreign to the purpose of this
work, to follow the nerves through all their dis-
tributions; but it may be remembered, that in
describing the different viscera, mention was
made of the nerves distributed to them. There
is one pair, however, called the intercostal or
great sympathetic nerve, which seems to require
particular notice, because it has an almost uni-
versal connection and correspondence with all
the other nerves of the body. Authors are not
perfectly agreed about the origin of the intercos-
tal;
† Observations on the Nervous system.

400 
PART V. OF THE BRAIN.
tal; but it may perhaps not improperly be de-
scribed, as beginning from filaments of the fifth
and sixth pair; it then passes out of the cranium,
through the bony canal of the carotid, from
whence it descends laterally close to the bodies
of the vertebræ, and receives branches from al-
most all the vertebral nerves; forming almost as
many ganglions in its course through the thorax
and abdomen. It sends off an infinite number
of branches to the viscera in those cavities, and
forms several plexuses with the branches of the
eight pair or par vagum.
That the nerves are destined to convey the
principles of motion and sensibility to the brain
from all parts of the system, there can be no
doubt; but how these effects are produced, no
one has ever yet been able to to determine. The
inquiry has been a constant source of hypothe-
sis in all ages, and has produced some ingenious
ideas, and many erroneous positions, but with-
out having hitherto afforded much satisfactory
information.
Some physiologists have considered a trunk of
nerves as a solid chord, capable of being divided
into an infinite number of filaments, by means
of which the impressions of feeling are convey-
ed to the sensorium commune. Others have
supposed it to be a canal, which afterwards se-
parates into more minute channels; or, perhaps,
as being an assemblage of many very small and
distinct tubes, connected to each other, and thus
3 forming


401
PART V. AND NERVES.
forming a cylindrical chord. They who con-
tend for their being solid bodies, are of opinion
that feeling is occasioned by vibration; so that,
for instance, according to this system, by prick-
ing the finger, a vibration would be occasioned
in the nerve, distributed through its substance;
and the effects of this vibration, when extended
to the sensorium, would be an excital of pain.
But the inelasticity, the softness, the connection,
and the situation of the nerves, are so many
proofs that vibration has no share in the cause of
feeling.
Others have supposed, that in the brain and
spinal marrow, a very subtile fluid is secreted,
and from thence conveyed through the imper-
ceptible tubes, which they consider as existing
in the nerves. They have farther supposed,
that this very subtile fluid, to which they have
given the name of animal spirits, is secreted in
the cortical substance of the brain and spinal
marrow, from whence it passes through the me-
dullary substance. This, like the other system,
is founded altogether on hypothesis; but it
seems to be an hypothesis derived from much
more probable principles, and there are many
ingenious arguments to be brought in its sup-
port.
Cc EXPLA-


402 
PART V. OF THE BRAIN.
EXPLANATION OF PLATE XXIX.
FIG. 1. Represents the inferior part of the
brain;—the Anterior part of the whole Spine,
including the Medulla Spinalis;—with the ori-
gin and large portions of all the NERVES.
A A, The anterior lobes of the cerebrum.
B B, The lateral lobes of the cerebrum. CC,
The two lobes of the cerebellum. D, Tuber
annulare. E, The passage from the third ven-
tricle to the infundibulum. F, The medulla ob-
longata, which sends off the medulla spinalis
through the spine. G G, That part of the os
occipitis which is placed above (HH) the trans-
verse processes of the first cervical vertebra. II, &c.
The seven cervical vertebræ, with their interme-
diate cartilages. KK, &c. The twelve dorsal
vertebræ, with their intermediate cartilages. LL,
&c. The five lumbar vertebræ, with their in-
termediate cartilages. M, The os sacrum. N,
The os coccygis.
NERVES.—11, The first pair of nerves,
named olfactory, which go to the nose. 22, The
second pair, named optic, which goes to form
the tunica retina of the eye. 33, The third,
named motor oculi; it supplies most of the mus-
cles of the eye-ball. 44, The fourth pair,
named pathetic,—which is wholly spent upon
the musculus trochlearis of the eye. 55, The
fifth

403
PART V. AND NERVES.
fifth pair divides into three branches.—The first,
named ophthalmic, goes to the orbit, supplies the
lachrymal gland, and sends branches out to the
forehead and nose.—The second, named supe-
rior maxillary, supplies the teeth of the upper
jaw, and some of the muscles of the lips.—The
third named inferior maxillary, is spent upon the
muscles and teeth of the lower jaw, tongue, and
muscles of the lips. 66, The sixth pair, which,
after sending off the beginning of the intercos-
tal or great sympathetic, is spent upon the ab-
ductor oculi. 77, The seventh pair, named au-
ditory, divides into two branches.—The largest,
named portio mollis, is spent upon the internal
ear.—The smallest, portio dura, joins to the
fifth pair within the internal ear by a reflected
branch from the second of the fifth; and with-
in the tympanum, by a branch from the third
of the fifth, named chorda tympani.—Vid. fig.
3. near B. 88, &c. The eighth pair, named
par vagum,—which accompanies the intercostal,
and is spent upon the tongue, larynx, pharynx,
lungs, and abdominal viscera. 99, The ninth
pair, which are spent upon the tongue. 1010,
&c. The intercostal, or great sympathetic,
which is seen from the sixth pair to the bottom
of the pelvis on each side of the spine, and
joining with all the nerves of the spine;—in its
progress supplying the heart, and, with the par
vagum, the contents of the abdomen and pelvis.
11, 11, The accessorius, which is spent upon
Cc2 the
 

404 
PART V. OF THE BRAIN. 
the sternocleido-mastoidæus and trapezius mus-
cles. 12 12, The first cervical nerves;—1313,
The second cervical nerves;—both spent up-
on the muscles that lie on the neck, and te-
guments of the neck and head. 1414, The third
cervical nerves, which, after sending off (15 15,
&c.) the phrenic nerves to the diaphragm, supply
the muscles and teguments that lie on the side
of the neck and top of the shoulder. 16 16,
The brachial plexus, formed by the fourth, fifth,
sixth, seventh cervicals, and first dorsal nerves.
—which supply the muscles and teguments of
the superior extremity. 1717, The twelve
dorsal, or proper intercostal nerves, which are
spent upon the intercostal muscles and some of
the large muscles which lie upon the thorax.
1818, The five lumbar pairs of nerves, which
supply the lumbar and abdominal muscles, and
some of the teguments and muscles of the infe-
rior extremity. 1919, The sacro-sciatic, or
posterior crural nerve, formed by the two infe-
rior lumbar, and three superior of the os sacrum.
This large nerve supplies the greatest part of the
muscles and teguments of the inferior extremity.
20, The stomachic plexus, formed by the eighth
pair. 2121, Branches of the solar or cæliac
plexus, formed by the eighth pair and intercos-
tals, which supply the stomach and chylopoietic
viscera. 2222, Branches of the superior and
inferior mesenteric plexuses, formed by the eighth
pair and intercostals, which supply the chylo-
poietic viscera, with part of the organs of urine 
and

ANATOMY
PLATE XXIX

 

405
PART V. AND NERVES.
and generation. 2323, Nerves which accom-
pany the sphermatic chord. 2424, The hypo-
gastric plexus, which supplies the organs of u-
rine and generation within the pelvis.
FIG. 2, 3, 4, 5. Shows different Views of the
Inferior part of the Brain, cut perpendicular-
ly through the Middle,—with the origin and
large Portions of the Nerves which pass out
through the bones of the Cranium,—and the
three first Cervical.
A, The anterior lobe. B, The lateral lobe of
the cerebrum. C, One of the lobes of the ce-
rebellum. D, Tuber annulare. E, Corpus py-
ramidale, in the middle of the medulla oblon-
gata. F, The corpus olivare, in the side of the
medulla oblongata. G, The medulla oblongata.
H, The medulla spinalis.
Nerves.—1 2 3 4 5 6 7 8 and 9, Pairs of nerves.
1010, Nervus accessorius, which comes from
—11, 12, and 13, The three first cervical
nerves.
PART VI. 


406 
PART VI. OF THE SENSE. 
PART VI.
O THE SENSES, AND THEIR ORGANS.
IN treating of the senses, we mean to confine
ourselves to the external ones of touch, taste,
smelling, hearing, and vision. The word sense,
when applied to these five, seems to imply not
only the sensation excited in the mind by certain
impressions made on the body, but likewise the
organ destined to receive and transmit these im-
pressions to the sensorium. Each of these or-
gans being of a peculiar structure, is suscepti-
ble only of particular impressions, which will be
pointed out as we proceed to describe each of
them separately.
SECT. I. Of Touch.
THE sense of touch may be defined to be the
faculty of distinguishing certain properties of bo-
dies by the feel. In a general acceptation, this
definition might perhaps not improperly be ex-
tended to every part of the body possessed of
sensibility (T), but it is commonly confined to
the
(T) In the course of this article, mention has often been
made of the sensibility or insensibility of different parts of
the body; it will therefore, perhaps, not be amiss to observe

407
PART VI. AND THEIR ORGANS.
the nervous papillæ of the cutis, or true skin
which, with its appendages, and their several
uses, have been already described.
The exterior properties of bodies, men as
their solidity, moisture, inequality, smoothness,
dryness, or fluidity, and likewise their degree of
heat, seem all to be capable of making different
impressions on the papillæ, and consequently of
exciting different ideas in the sensorium com-
mune. But the organ of touch, like all the
other senses, is not equally delicate in every
part of the body, or in every subject ; being in
some much more exquisite than it is in others.
SECT.
in this place, that many parts which were formerly suppos-
ed to possess the most exquisite sense. are now known to
have but little or no feeling, at least in a sound state: for in
an inflamed state, even the bones, the most insensible parts
of any, become susceptible of the most painful sensations.
This curious discovery is due to the late Baron Haller. His
experiments prove, that the bones, cartilages, ligaments,
tendons, epidermis and membranes (as the pleura, pericar-
dium, dura and pia mater, periosteum, &c.) may in a healthy
state be considered as insensible. As sensibility depends on
the brain and nerves, of course different parts will possess
a greater or less degree of feeling in proportion as they
are supplied with a greater or smaller number or nerves.
Upon the principle it is, that the skin, muscles, stomach,
intestines, urinary bladder, ureters, uterus, vagina, penis,
tongue, and retina are extremely sensible while the lungs
and glands have only an obscure degree of feeling. 

408 
PART VI. OF THE SENSES.
SECT. II. Of the Taste.
The sense of taste is seated chiefly in the
tongue; the situation and figure of which are
sufficiently known.
On the upper surface of this organ we may
observe a great number of papillæ, which, on
account of their difference in size and shape,
are commonly divided into three classes. The
largest are situated towards the basis of the
tongue. Their number commonly varies from
seven to nine, and they seem to be mucous fol-
licles. Those of the second class are somewhat
smaller, and of a cylindrical shape. They are
most numerous about the middle of the tongue.
Those of the third class are very minute, and of
a conical shape. They are very numerous on
the apex and edges of the tongue, and have been
supposed to be formed by the extremities of its
nerves.
We observe a line, the linea linguæ mediana,
running along the middle of the tongue, and di-
viding it as it were into portions. Towards the
basis of the tongue, we meet with a little cavity,
named by Morgagni foramen cæcum, which
seems to be nothing more than a common termi-
nation of some of the excretory ducts of mu-
cous glands situated within the substance of the
tongue.
We

409
PART VI. AND THEIR ORGANS.
We have already observed, that this organ is
every where covered by the cuticle, which, by
forming a reduplication, called the frænum, at
its under part, serves to prevent the too great
motion of the tongue, and to fix in it its situation.
But, besides this attachment, the tongue is con-
nected by means of its muscles and membranous
ligaments, to the lower jaw, the os hyoides, and
the styloid processes.
The principal arteries of the tongue are the
linguales, which arise from the external carotid.
Its veins empty themselves into the external ju-
gulars. Its nerves arise from the fifth, eighth,
and ninth, pair.
The variety of tastes seems to be occasioned
by the different impressions made on the papil-
læ by the food. The different state of the pa-
pillæ with respect to their moisture, their figure,
or their covering, seems to produce a considera-
ble difference in the taste, not only in diffe-
rent people, but in the same subject, in sickness
and in health. The great use of the taste seems
to be to enable us to distinguish wholesome and
salutary food from that which is unhealthy ;
and we observe that many quadrupeds, by hav-
ing their papillæ (U) very large and long, have
the
(U) Malpighi's description of the papillæ, which has been
copied by many anatomical writers, seems to have been
taken chiefly from the tongues of sleep.

410 
PART VI. OF THE SENSES.
the faculty of distinguishing flavours with infi-
nite accuracy.
SECT III. Of Smelling.
THE sense of smelling, like the sense of taste,
seems intended to direct us to a proper choice of
aliment, and is chiefly seated in the nose, which
is distinguished into its external and internal parts.
The situation and figure of the former of these
do not seem to require a definition. It is compos-
ed of bones and cartilages, covered by muscu-
lar fibres and by the common teguments. The
bones make up the upper portion, and the car-
tilages the lower one. The septum narium,
like the nose, is likewise in part bony, and in
part cartilaginous. These bones and their con-
nexions were described in the osteology.
The internal part of the nose, besides the ossa
spongiosa, has six cavities or sinuses, the max-
illary, the frontal, and the sphenoid, which were
all described with the bones of the head. They
all open into the nostrils; and the nose likewise
communicates with the mouth, larynx, and
pharynx, posteriorly behind the velum palati.
All these several parts, which are included in
the internal division of the nose, viz. the inner
surface of the nostrils, the lamellæ of the ossa
spongiosa, and the sinuses, are lined by a very
vascular membrane, which though not unknown
to the ancients, was first well described by
Schneider

411
PART VI. AND THEIR ORGANS.
Schneider *, and is therefore now commonly
named membrana pituitaria Schneideri. This
membrane is truly the organ of smelling; but
its real structure does not yet seem to be perfect-
ly understood. It appears to be a continuation
of the cuticle, which lines the inner surface of
the mouth, in some parts of the nose it is
smooth and firm, and in others it is loose and
spongy. It is constantly moistened by a mu-
cous secretion; the finer parts of which are
carried off by the air we breathe, and the re-
mainder, by being retained in the sinuses, ac-
quires considerable consistence. The manner in
which this mucus is secreted has not yet been sa-
tisfactorily ascertained; but it seems to be by
means of mucous follicles.
Its arteries are branches of the internal max-
illary and internal carotid. Its veins empty
themselves into the internal jugulars. The first
pair of nerves, the olfactory, are spread over
every part of it, and it likewise receives branches
from the fifth pair.
After what has been said of the pituitary mem-
brane, it will not be difficult to conceive how
the air we draw in at the nostrils, being im-
pregnated with the effluvia of bodies, excites in
us that kind of sensation we call smelling. As
these effluvia, from their being exceedingly
light and volatile, cannot be capable in a small
quantity
De Catarrho, lib. iii.

412 
PART VI. OF THE SENSES.
quantity of making any great impression on the
extremities of the olfactory nerves, it was ne-
cessary to give considerable extent to the pituitary
membrane, that by this means a greater num-
ber of odoriferous particles might be admitted
at the same time. When we wish to take in
much of the effluvia of any thing, we naturally
close the mouth, that all the air we inspire may
pass through the nostrils; and at the same time,
by means of the muscles of the nose, the nos-
trils are dilated, and a greater quantity of air
is drawn into them.
In many quadrupeds, the sense of smelling
is much more extensive and delicate than it is in
the human subject; and in the human subject it
seems to be more perfect the less it is vitiated by
a variety of smells. It is not always in the
same state of perfection, being naturally affect-
ed by every change of the pituitary membrane,
and of the lymph with which that membrane is
moistened.
SECT. IV. Of Hearing.
BEFORE we undertake to explain the manner
in which we are enabled to receive the impressi-
ons of sound, it will be necessary to describe the
ear, which is the organ of hearing. It is com-
monly distinguished into external and internal.
The former of these divisions includes all that
we are able to discover without dissection, and
the 

413
PART VI. AND THEIR ORGANS
the meatus auditorius, as far as the typanum;
and the latter, all the other parts of the ear.
The external ear is a cartilaginous funnel co-
vered by the common integuments, and attach-
ed by means of its ligaments and muscles, to
the temporal bone. Although capable only of
a very obscure motion, it is found to have seve-
ral muscles. Different parts of it are distinguish-
ed by several names; all its cartilaginous part is
called ala or wing, to distinguish it from the
soft and pendent part below, called the lobe. Its
outer circle or border is called helix, and the se-
micircle within this, antihelix. The moveable
cartilage placed immediately before the meatus
auditorius, which it may be made to close ex-
actly, is named tragus; and an eminence op-
posite to this at the extremity of the antihelix,
is called antitragus. The concha is a consider-
able cavity formed by the extremities of the he-
lix and antihelix. The meatus auditorius,
which at its opening is cartilaginous, is lined
with a very thin membrane, which is a conti-
nuation of the cuticle from the surface of the
ear.
In this canal we find a yellow wax, which is
secreted by a number of minute glands or folli-
cles, each of which has an excretory duct. This
secretion; which is at first of an oily consistence,
defends the membrane of the typanum from the
injuries of the air; and by its bitterness, pre-
vents minute insects from entering into the ear.
But

414 
PART VI. OF THE SENSES.
But when from neglect or disease it accumulates
in too great a quantity, it sometimes occasions
deafness. The inner extremity of the meatus is
closed by a very thin transparent membrane, the
membrana tympani, which is set in a bony cir-
cle like the head of a drum. In the last century
Rivinus, professor at Leipsic, fancied he had
discovered a hole in this membrane, surrounded
by a sphincter, and affording a passage to the
air, between the external and internal ear. Cow-
per, Heister, and some other anatomists, have
admitted this supposed foramen, which certain-
ly does not exist. Whenever there is any open-
ing in the membrana tympani, it may be consi-
dered as accidental. Under the membrana tym-
pani runs a branch of the fifth pair of the nerves,
called chorda tympani; and beyond this mem-
brane is the cavity of the tympanum, which is
about seven or eight lines wide, and half so ma-
ny in depth; it is semispherical, and every
where lined by a very fine membrane. There
are four openings to be observed in this cavity.
It communicates with the mouth by means of
the Eustachian tube. This canal, which is in
part bony and in part cartilaginous, begins by a
very narrow opening at the anterior and almost
superior, part of the tympanum, increasing in
size as it advances towards the palate of the
mouth, where it terminates by an oval opening.
This tube is every where lined by the same mem-
brane that covers the inside of the mouth. The
real

415
PART VI. AND THEIR ORGANS.
real use of this canal does not seem to have been
hitherto satisfactorily ascertained; but sound
would seem to be conveyed through it to the
membrana tympani, deaf persons being often
observed to listen attentively with their mouths
open. Opposite to this is a minute passage,
which leads to the sinuosities of the mastoid pro-
cess; and the two other openings, which are in
the internal process of the os petrosum, are the
fenestra ovalis, and fenestra rotunda, both of
which are covered by a very fine membrane.
There are three distinct bones in the cavity
of the tympanum; and these are the malleus,
incus, and stapes. Bedsides these there is a fourth,
which is the os orbiculare, considered by some
anatomists as a process of the stapes, which is
necessarily broken off by the violence we are
obliged to use in getting at these bones; but
when accurately considered, it seems to be a
distinct bone.
The malleus is supposed to resemble a ham-
mer, being larger at one extremity, which is its
head, than it is at the other, which is its han-
dle. The latter is attached to the membrana
tympani, and the head of the bone is articulat-
ed with the incus.
The incus, as it is called from its shape, though
it seems to have less resemblance to an anvil than
to one of the dentes molares with its roots wide-
ly separated from each other, is distinguished in-
to its body and its legs. One of its legs is plac-
3 ed


416 
PART VI. OF THE SENSES.
ed at the entry of the canal which leads to the
mastoid process; and the other, which is some-
what longer, is articulated with the stapes, or
rather with the os orbiculare, which is placed
between them.
The third bone is very properly named stapes,
being perfectly shaped like a stirrup. Its basis
is fixed into the fenestra ovalis, and its upper
part is articulated with the os orbiculare. What
is called the fenestra rotunda, though perhaps
improperly, as it is more oval than round, is
observed a little above the other, in an emi-
nence formed by the os petrosum, and is closed
by a continuation of the membrane that lines
the inner surface of the tympanum. The
stapes and malleus are each of them furnished
with a little muscle, the stapedeus and tensor tym-
pani. The first of these, which is the smallest in
the body, arises from a little cavern in the pos-
terior and upper part of the cavity of the tym-
panum; and its tendon, after passing through
a hole in the same cavern, is inserted at the
back part of the head of the stapes. This mus-
cle, by drawing the stapes obliquely upwards, as-
sists in stretching the membrana tympani.
The tensor tympani (X,) or internus malei,
as it is called by some writers, arises from the
carti-
(X) Some anatomists describe three muscles of the mal-
leus: but only this one seems to deserve the name of muscle;
what are called the externus and obliquus mollei, seeming to
be ligaments rather than muscles.

417
PART VI. AND THEIR ORGANS.
cartilaginous extremity of the Eustachian tube,
and is inserted into the back part of the handle
of the malleus, which it serves to pull inwards,
and of course helps to stretch the membrana tym-
pani.
The labyrinth is the only part of the ear which
remains to be described. It is situated in the os
petrosum, and is separated from the tympanum
by a partition which is every where bony, except
at the two fenestræ. It is composed of three
parts; and these are the vestibulum, the semicir-
cular canals, and the cochlea.
The vestibulum is an irregular cavity, much
smaller than the tympanum, situated nearly in
the centre of the os petrosum, between the tym-
panum, the cochlea, and the semicircular canals.
It is open on the side of the tympanum by means
of the fenestra ovalis, and communicates with
the upper portion of the cochlea by an oblong
foramen, which is under the fenestra ovalis, from
which it is separated only by a very thin parti-
tion.
Each of the three semicircular canals forms
about half a circle of nearly a line in diameter,
and running each in a different direction, they
are distinguished into vertical, oblique, and hori-
zontal. These three canals open by both their
extremities into the vestibulum; but the vertical
and the oblique being united together at one of
their extremities, there are only five orifices to be
seen in the vestibulum.
Dd The


418 
PART VI. OF THE SENSES.
The cochlea is a canal which takes a spiral
course, not unlike the shell of a snail. From its
basis to its apex it makes two turns and a half;
and is divided into two canals by a very thin la-
mina or septum, which is in part bony and in
part membranous, in such a manner that these
two canals only communicate with each other at
the point. One of them opens into the vestibu-
lum, and the other is covered by the membrane
that closes the fenestra rotunda. The bony la-
mella which separates the two canals is exceed-
ingly thin, and fills about two thirds of the dia-
meter of the canal. The rest of the septum is
composed of a most delicate membrane, which
lines the whole inner surface of the cochlea, and
seems to form this division in the same man-
ner as the two membranous bags of the pleura,
by being applied to each other, form the medias-
tinum.
Every part of the labyrinth is furnished with
a very delicate periosteum, and filled with a wa-
tery fluid, secreted as in other cavities. This
fluid transmits to the nerves the vibrations it re-
ceives from the membrane closing the fenestra ro-
tunda, and from the basis of the stapes, where
it rests on the fenestrum ovale. When this fluid
is collected in too great quantity, or is compressed
by the stapes, it is supposed to escape through
two minute canals or aqueducts, lately described
by 

419
PART VI. AND THEIR ORGANS.
by Dr Cotunni *, an ingenious physician at Na-
ples. One of these aqueducts opens into the
bottom of the vestibulum, and the other into
the cochlea, near the fenestra rotunda. They
both pass through the os petrosum, and com-
municate with the cavity of the cranium where
the fluid that passes through them is absorbed;
and they are lined by a membrane which is sup-
posed to be a production of the dura mater.
The arteries of the external ear come from
the temporal and other branches of the external
carotid, and its veins pass into the jugular. The
internal ear receives branches of arteries from the
basilary and carotids, and its veins empty them-
selves into the sinuses of the dura mater, and into
the internal jugular.
The portio mollis of the seventh pair is
distributed through the cochlea, the vestibu-
lum, and the semi-circular canals; and the
portio dura sends off a branch to the tympa-
num, and other branches to the external ear and
parts near it.
The sense of hearing, in producing which all
the parts we have described assist, is occasioned
by a certain modulation of the air collected by the
funnel-like shape of the external ear, and con-
veyed through the meatus auditorius to the mem-
brana tympani. That sound is propagated by
means of the air, is very easily proved by ring-
Dd2 ing
* De aquæductibus Auris Humanæ Internæ, 8ve, 1760.

420 
PART VI. OF THE SENSES.
ing a bell under the receiver of an air-pump;
the sound it affords being found to diminish gra-
dually as the air becomes exhausted, till at length
it ceases to be heard-at all. Sound moves through
the air with infinite velocity; but the degree of
its motion seems to depend on the state of the
air, as it constantly moves faster in a dense and
dry, than it does in a moist and rarefied air. See
Acoustics, n° 20.
That the air vibrating on the membrana tym-
pani communicates its vibration to the different
parts of the labyrinth, and by means of the
fluid contained in this cavity affects the auditory
nerve so as to produce sound, seems to be very
probable : but the situation, the minuteness, and
the variety of the parts which compose the ear,
do not permit much to be advanced with certain-
ty concerning their mode of action.
Some of these parts seem to constitute the im-
mediate organ of hearing, and these are all the
parts of the vestibulum: but there are others
which seem intended for the perfection of this
sense, without being absolutely essential to it. It
has happened, for instance, that the membrana
tympani, and the little bones of the ear, have
been destroyed by disease, without depriving the
patient of the sense of hearing (Y).
Sound
(Y) This observation has led to a supposition, that a per-
foration of this membrane may in some cases of deafness be
useful; and Mr. Cheselden relates, that, some years ago, a 

421
Part VI. AND THEIR ORGANS.
Sound is more or less loud in proportion to
the strength of the vibration; and the variety
of sounds seems to depend on the difference of
this vibration; for the more quick and frequent
it is, the more acute will be the sound, and vice
versa.
Before we conclude this article, it will be
right to explain certain phenomena, which
will be found to have a relation to the organ of
hearing.
Every body has, in consequence of particular
sounds, occasionally felt that disagreeable sensa-
tion which is usually called setting the teeth on
edge: and the cause of this sensation may be
traced to the communication which the portio
dura of the auditory nerve has with the branches
of the fifth pair that are distributed to the teeth,
being probably occasioned by the violent tremor
produced in the membrana tympani by these ve-
ry acute sounds. Upon the same principle we
may explain the strong idea of sound which a
person has who holds a vibrating string between
his teeth.
The humming which is sometimes perceived
in the ear, without any exterior cause, may be
occasioned either by an increased action of the
arteries in the ears, or by convulsive contractions
of
malefactor was pardoned on condition that he should submit
to this operation; but the public clamour raised against it
was so great, that it was thought right not to perform it. 

422 
PART VI. OF THE SENSES.
of the muscles of the malleus and stapes, affecting
the auditory nerve in such a manner as to produce
the idea of found. An ingenious philosophical
writer * has lately discovered, that there are
sounds liable to be excited in the ear by irritation,
and without any assistance from the vibrations of
the air.
SECT. V. Of Vision.
The eyes, which constitute the organ of vi-
sion, are situated in two bony cavities named
orbits, where they are surrounded by several
parts, which are either intended to protect
them from external injury, or to assist in their
motion.
The globe of the eye is immediately covered
by two eye-lids or palpebræ, which are compos-
ed of muscular fibres covered by the common in-
teguments, and lined by a very fine and smooth
membrane, which is from thence extended over
part of the globe of the eye, and is called tunica
conjunctiva. Each eye-lid is cartilaginous at its
edge; and this border which is called tarsus, is
furnished with a row of hairs named cilia or eye-
lashes.
The
* Elliot's Philosophical Observations on the Senses of Vi-
sion and Hearing, 8vo.

423
PART VI. AND THEIR ORGANS.
The cilia serve to protect the eye from insects
and minute bodies floating in the air, and like-
wise to moderate the action of the rays of light
in their passage to the retina. At the roots of
these hairs there are sebaceous follicles, first no-
ticed by Meibomius, which discharge a glutinous
liniment. Sometimes the fluid they secrete has
too much viscidity, and the eye-lids become
glued to each other.
The upper border of the orbit is covered by
the eye-brows or supercilia, which by means of
their two muscles are capable of being brought
towards each other, or of being carried upwards.
They have been considered as serving to protect
the eyes, but they are probably intended more for
ornament than utility (Z).
The orbits, in which the eyes are placed, are
furnished with a good deal of fat, which affords
a soft bed on which the eye performs its several
motions. The inner angle of each orbit, or that
part of it which is near the nose, is called canthus
major, or the great angle; and the outer angle,
which is on the opposite side of the eye, is the
canthus minor, or little angle.
The little reddish body which we observe in
the great angle of the eye-lids, and which is call-
ed caruncula lachrymalis, is supposed to be of a
glandular structure, and, like the follicles of the
eye-
(Z) It is observable, that the eye-brows are peculiar to the
human species.

424 
PART VI. OF THE SENSES.
eye-lids, to secrete an oily humour. But its
structure and use do not seem to have been hi-
therto accurately determined. The surface of the
eye is constantly moistened by a very fine limpid
fluid called the tears, which is chiefly, and per-
haps wholly, derived from a large gland of the
conglomerate kind, situated in a small depression
of the os frontis near the outer angle of the eye.
Its excretory ducts pierce the tunica conjunctiva
just above the cartilaginous borders of the upper
eye-lids. When the tears were supposed to be
secreted by the caruncule, this gland was called
glandula innominata; but now that its structure
and uses are ascertained, it very properly has the
name of glandula lachrymalis. The tears pour-
ed out by the ducts of this gland are, in a natu-
ral and healthy state, incessantly spread over the
surface of the eye, to keep it clear and transpa-
rent, by means of the eye-lids, and as constantly
pass out at the opposite corner of the eye or in-
ner angle, through two minute orifices, the punc-
ta lachrymalia (A); being determined into these
little openings by a duplication of the tunica con-
jundiva, shaped like a crescent, the two points
of which answer to the puncta This reduplica-
tion is named membrana, or valvula semilunaris.
Each
(A) It sometimes happens, that this very pellucid fluid,
which moistens the eye, being poured out through the ex-
cretory ducts of the lachrymal gland faster than it can be
carried off through the puncta, trickles down the cheek,
and is then strictly and properly called tears.

425
PART VI. AND THEIR ORGANS.
Each of these puncta is the beginning of a small
excretory tube, through which the tears pass into
a little pouch or reservoir, the sacculus lachryma-
lis, which lies in an excavation formed partly by
the nasal process of the os maxillare superius,
and partly by the os unguis. The lower part of
this sac forms a duct called the ductus ad nares,
which is continued through a bony channel, and
opens into the nose, through which the tears are
occasionally discharged (B).
The motions of the eye are performed by six
muscles: four of which are straight and two
oblique. The straight muscles are distinguished
by the names of elevator, depressor, adductor, and
abductor, from their several uses in elevating and
depressing the eye, drawing it towards the nose,
or carrying it from the nose towards the temple.
All these four muscles arise from the bottom of
the orbit, and are inserted by flat tendons into
the globe of the eye. The oblique muscles are
intended for the more compound motions of the
eye. The first of these muscles, the obliquus
superior, does not, like the other four muscles
we have described, arise from the bottom of the
orbit, but from the edge of the foramen that
transmits the optic nerve, which separates the
origin
(B) When the ductus ad nares becomes obstructed in con-
sequence of disease, the tears are no longer able to pass into
the nostrils; the sacculus lachrymalis becomes distended;
and inflammation, and sometimes ulceration, taking place,
constitute the disease called fistula lachrymalis.

426 
PART VI. OF THE SENSES. 
origin of this muscle from that of the others.
From this beginning it passes in a straight line
towards a very small cartilaginous ring, the situ-
ation of which is marked in the skeleton by a
little hollow in the internal orbitar process of the
os frontis. The tendon of the muscle, after
passing through this ring, is inserted into the up-
per part of the globe of the eye, which it serves
to draw forwards, at the same time turning the
pupil downwards.
The obliquus inferior arises from the edge of
the orbit, under the opening of the ductus lach-
rymalis; and is inserted somewhat posteriorly
into the outer side of the globe, serving to draw
the eye forwards and turn the pupil upwards.
When either of these two muscles acts separately,
the eye is moved on its axis; but when they act
together, it is compressed both above and below.
The eye itself, which is now to be described,
with its tunics, humours, and component parts,
is nearly of a spherical figure. Of its tunics, the
conjunctiva has been already described as a par-
tial covering, reflected from the inner surface of
the eye-lids over the anterior portion of the eye.
What has been named albuginea cannot pro-
perly be considered as a coat of the eye, being
in fact nothing more than the tendons of the
straight muscles spread over some parts of the
sclerotica. 
The immediate tunics of the eye, which are
to be demonstrated when its partial coverings,
and

427
PART VI. AND THEIR ORGANS.
and all the other parts with which it is surround-
ed, are removed, are the sclerotica, cornea, cho-
roides, and retina.
The sclerotica, which is the exterior coat, is
every where white and opaque, and is joined at
its anterior edge to another, which has more
convexity than any other part of the globe, and
being exceedingly transparent is called cornea (C).
These two parts are perfectly different in their
structure; so that some anatomists suppose them
to be as distinct from each other as the glass of
a watch is from the case into which it is fixed.
The sclerotica is of a compact fibrous structure;
the cornea, on the other hand, is composed of a
great number of lamina united by cellular mem-
brane. By macerating them in boiling water,
they do not separate from each other, as some
writers have asserted; but the cornea soon soft-
ens, and becomes of a glutinous consistence.
The ancients supposed the sclerotica to be a
continuation of the dura mater. Morgagni and
some other modern writers are of the same opi-
nion; but this point is disputed by Winslow,
Haller, Zin, and others. The truth seems to
be, that the sclerotica, though not a production
of the dura mater, adheres intimately to that
membrane.
The
(C) Some writers, who have given the name of cornea to
all this outer coat, have named what is here and most com-
monly called sclerotica, cornea opaca; and its anterior and
transparent portion, cornea lucida.

428 
PART VI. OF THE SENSES.
The choroides is so called because it is furnish-
ed with a great number of vessels. It has like-
wise been named uvea, on account of its resem-
blance to a grape. Many modern anatomical
writers have considered it as a production of the
pia mater. This was likewise the opinion of the
ancients; but the strength and thickness of the
choroides, when compared with the delicate
structure of the pia mater, are sufficient proofs of
their being two distinct membranes.
The choroides has of late generally been de-
scribed as consisting of two laminæ; the inner-
most of which has been named after Ruysch, who
first described it. It is certain, however, that
Ruysch's distinction is ill founded, at least with
respect to the human eye, in which we are una-
ble to demonstrate any such structure, although
the tunica choroides of sheep and some other
quadrupeds may easily be separated into two
layers.
The choroides adheres intimately to the scle-
rotica round the edge of the cornea; and at the
place of this union, we may observe a little
whitish areola, named ligamentum ciliare, though
it is not of a ligamentous nature.
They who suppose the choroides to be com-
posed of two laminæ, describe the external one
as terminating in the ligamentum ciliare, and the
internal one as extending farther to form the
iris, which is the circle we are able to distinguish
through the cornea: but this part is of a very
different 

429
PART VI. AND THEIR ORGANS.
different structure from the choroides; so that
some late writers have perhaps not improperly
considered the iris as a distinct membrane. It
derives its name from the variety of its colours,
and is perforated in the middle. This perfora-
tion, which is called the pupil or sight of the
eye, is closed in the fœtus by a very thin vascular
membrane. This membrana pupillaris common-
ly disappears about the seventh month.
On the under side of the iris we observe many
minute fibres, called ciliary processes, which pass
in radii or parallel lines from the circumference
to the centre. The contraction and dilatation
of the pupil are supposed to depend on the ac-
tion of these processes. Some have considered
them as muscular, but they are not of an irritable
nature; others have supposed them to be fila-
ments of nerves: but their real structure has
never yet been clearly ascertained.
Besides these ciliary processes, anatomists usu-
ally speak of the circular fibres of the iris, but
no such seem to exist.
The posterior surface of the iris, the ciliary
processes, and part of the tunica choroides, are
covered by a black mucus for the purposes of ac-
curate and distinct vision; but the manner in
which it has been secreted has not been deter-
mined.
Immediately under the tunica choroides we
find the third and inner coat, called the retina,
which

430 
PART VI. OF THE SENSES.
which seems to be merely an expansion of the
pulpy substance of the optic nerve, extending to
the border of the crystaline humour.
The greatest part of the globe of the eye,
within these several tunics, is filled by a very
transparent and gelatinous humour of consider-
able consistence, which, from its supposed resem-
blance to fused glass, is called the vitreous humour.
It is invested by a very fine and delicate mem-
brane, called tunica vitrea, and sometimes arach-
noides.—It is supposed to be composed of two
laminæ ; one of which dips into its substance,
and by dividing the humour into cells adds to
its firmness. The fore-part of the vitreous hu-
mour is a little hollowed, to receive a very white
and transparent substance of a firm texture, and
of a lenticular and somewhat convex shape,
named the crystaline humour. It is included in a
capsula, which seems to be formed by a separa-
tion of the two laminæ of the tunica vitrea.
The fore-part of the eye is filled by a very thin
and transparent fluid, named the aqueous humour,
which occupies all the space between the crystal-
line and the prominent cornea.—The part of the
choroides which is called the iris, and which
comes forward to form the pupil, appears to be
suspended as it were in this humour, and has oc-
casioned this portion of the eye to be distin-
guished into two parts. One of these, which is
the little space between the anterior surface of
the crystalline and the iris, is called the posterior
chamber; 

431
PART VI. AND THEIR ORGANS.
chamber; and the other, which is the space
between the iris and the cornea, is called the
anterior chamber of the eye (D). Both these
spaces are completely filled with the aqueous
humour. (E).
The eye receives its arteries from the internal
carotid through the foramina optica; and its
veins pass through the foramina lacera, and
empty themselves into the lateral sinuses. Some
of the ramifications of these vessels appear on the
inner surface of the iris, where they are seen
to make very minute convolutions, which are
sufficiently remarkable to be distinguished by
the name of circulus arteriosus, though per-
haps improperly, as they are chiefly branches of
veins.
The
(D) We are aware that some anatomists, particularly Lieu-
taud, are of opinion, that the iris is every where in close
contact with the crystalline, and that it is of course right to
speak only of one chamber of the eye; but as this does
not appear to be the case, the situation of the iris and the
two chambers of the eye are here described in the usual
way.
(E) When the crystalline becomes opaque, so as to pre-
vent the passing of the rays of light to the retina, it con-
stitutes what is called a contract; and the operation of
couching consists in removing the diseased crystalline from
its bed in the vitreous humour. In this operation the cor-
nea is perforateed, and the aqueous humour escapes out of
the eye, but it is constantly renewed again in a very short
time. The manner, however, in which it is secreted, has
not yet been determined. 

432 
PART VI. OF THE SENSES.
The optic nerve passes in at the posterior part
of the eye, in a considerable trunk, to be ex-
panded for the purposes of vision, of which it
is now universally supposed to be the immediate
seat. But Messrs. Mariotte and Mery contend-
ed, that the choroides is the seat of this sense;
and the ancients supposed the crystalline to be
so. Besides the optic, the eye receives branches
from the third, fourth, fifth, and sixth pair of
nerves.
The humours of the eye, together with the
cornea, are calculated to refract and converge
the rays of light in such a manner as to form at
the bottom of the eye a distinct image of the
object we look at; and the point where these
rays meet is called the focus of the eye. On the
the retina, as in the camera obscura, the object
is painted in an inverted position; and it is on-
ly by habit that we are enabled to judge of its
true situation, and likewise of its distance and
magnitude. To a young gentleman who was
born blind, and who was couched by Mr. Che-
selden, every object (as he expressed himself)
seemed to touch his eyes as what he felt did his
skin; and he thought no objects so agreeable as
those which were smooth and regular, although
for some time he could form no judgment of
their shape, or guess what it was in any of them
that was pleasing to him.
In order to paint objects distinctly on the re-
tina, the cornea is required to have such a de-
3 gree


433
PART VI. AND THEIR ORIGIN.
gree of convexity, that the rays of light may be
collected at a certain point, so as to terminate
exactly on the retina—If the cornea is too pro-
minent, the rays, by diverging too soon, will
be united before they reach the retina, as is
the case with near-sighted people or myopes; and
on the contrary, if it is not sufficiently convex,
the rays will not be perfectly united when they
reach the back part of the eye; and this hap-
pens to long-sighted people or presbi, being found
constantly to take place as we approach to old
age, when the eye gradually flattens (F). These
defects are to be supplied by means of glasses.
He who has too prominent an eye, will find
his vision improved by means of a concave glass;
and upon the same principles, a convex glass
will be found useful to a person whose eye is na-
turally too flat.
(F) Upon this principle, they who in their youth are
near-sighted may expert to see better as they advance in life,
as their eyes gradually become more flat.
Ee EXPLA-


434 
PART VI. OF THE SENSES.
EXPLANATION OF PLATE XXX.
FIGURE 1. Shows the Lachrymal Canals, after
the Common Teguments and Bones have been
cut away.
a, The lachrymal gland, b, The two puncta
lachrymalia, from which the two lychrymal ca-
nals proceed to c, The lachrymal sac. d, The
large lachrymal duct. e, Its opening into the
nose. f, The caruncula lachrymalis. g, The
eye-ball.
FIG. 2. An interior View of the Coats and Hu-
mours of the Eye.
aaaa, The tunica sclerotica cut in four an-
gles, and turned back, b b b b, The tunica cho-
roides adhering to the inside of the sclerotica,
and the ciliary vessels are seen passing over—cc,
The retina which covers the vitreous humour.
dd, The ciliary processes, which were conti-
nued from the choroid coat, ee, The iris. f,
The pupil.
FIG. 3. Shows the Optic Nerves, and Muscles
of the Eye.
aa, The two optic nerves before they meet.
b, The two optic nerves conjoined. c, The
right 

435
PART VI. AND THEIR ORGANS.
right optic nerve. d, Musculus attolens palpe-
bræ superioris. e, Attollens oculi. f, Abduc-
tor. gg, Obliquus superior, or trochlearis. h,
Adductor. i, The eye-ball.
FIG. 4. Shows the Eye-balls with its Muscles,
a, The optic nerve. b, Musculus trochlearis,
c, Part of the os frontis, to which the trochlea
or pully is fixed, through which,—d, The ten-
dons of the trochlearis passes, e, Attollens oc-
culi. f, Adductor oculi. g, Abductor oculi.
h, Obliquus inferior, i, Part of the superior
maxillary bone to which it is fixed. k, The
eye-ball.
FIG. 5. Represents the Nerves and Muscles of
the Right Eye, after part of the Bones of the
orbit have been cut away.
A, The eye-ball. B, The lachrymal gland.
C, Musculus abductor oculi. D, Attolens. E,
Levator palpebræ superioris. F, Depressor oculi.
G. Adductor. H, Obliquus superior, with its pul-
ly. I, Its insertion into the sclerotic coat. K,
Part of the obliquus inferior. L, The anterior
part of the os frontis cut. M, The crista galli
of the ethmoid bone. N, The posterior part of
the sphenoid bone. O, Transverse spinous pro-
cess of the sphenoid bone. P, The carotid ar-
tery, denuded where it passes through the bones.
Q, The 

436 
PART VI. OF THE SENSES. 
Q, The carotid artery within the cranium.
R, The ocular artery.
Nerves—aa, The optic nerve. b, The
third pair.—c, Its joining with a branch of the
first branch of the fifth pair, to form l,—The len-
ticular ganglion, which sends off the ciliary
nerves, d, ee, The fourth pair. f, The trunk
of the fifth pair. g, The first branch of the fifth
pair, named ophthalmic. h, The frontal branch
of it. i, Its ciliary branches, along with which
the nasal twig is sent to the nose. k, Its branch
to the lachrymal gland. l, The lenticular gan-
glion. m, The second branch of the fifth pair,
named superior maxillary. n, The third branch
of the fifth pair, named inferior maxillary, o,
The sixth pair of nerves,—which sends off p,
The beginning of the great sympathetic. q, The
remainder of the sixth pair, spent on c, The ab-
ductor oculi.
FIG. 6. Represents the head of a youth, where
the upper part of the cranium is sawed off,—to
show the upper part of the brain, covered by the
pia mater, the vessels of which are minutely
filled with wax.
AA, The cut edges of the upper part of the
cranium. B, The two tables and intermediate
diploë. BB, The two hemispheres of the ce-
rebrum. CC, The incisure made by the falx.
D, Part of the tentorium cerebello super ex-
pansum.

437
PART VI. AND THEIR ORGANS.
pansum. E, Part of the falx, which is fixed to
the crista galli.
FIG. 7. Represents the parts of the external
Ear, with the Parotid Gland and its Ducts.
a a, The helix, b, The antihelix. c, The
antitragus. d, The tragus. e, The lobe of the
ear. f, The cavitas innominata. g, The scapha.
h, The concha. ii, The parotid gland. k, A
lymphatic gland, which is often found before
the tragus. l. The duct of the parotic gland.
m, Its opening into the mouth.
FIG. 8. A view of the posterior part of the ex-
ternal ear, meatus auditorius, tympanum,
with its small bones, and Eustachian tube of
the right side.
a, The back part of the meatus, with the
small ceruminous glands. b, The incus. c,
Malleus. d, The chorda tympani. e, Mem-
brana tympani. f, Eustachian tube. g, Its
mouth from the fauces.
FIG. 9. Represents the anterior part of the right
external ear, the cavity of the tympanum—
its small bones, cochlea, and semicircular ca-
nals.
a, The malleus. b, Incus with its long leg,
resting upon the stapes. c, Membrana tympani.
I d e, The 

438 
PART VI. OF THE SENSES, &c. 
d, e, The Eustachian tube, covered by part of
— f f, The musculus circumflexus palati. 1 2 3,
The three semicircular canals. 4, The vestible.
5, The cochlea. 6, The portio mollis of the
seventh pair of nerves.
FIG. 10. Shews the muscles which compose the
fleshy substance of the tongue.
a a, The tip of the tongue, with some of the
papillæ minimæ. b, The root of the tongue.
c, Part of the membrane of the tongue, which
covered the epiglottis. dd, Part of the mus-
culus hyo-glossus. e, The lingualis. f, Genio-
glossus. gg, Part of the stylo-glossus.
THE END.
DIRECTIONS FOR PLACING THE PLATES.
Plate 19 to face page 138
20 144
21 } 158
22 }
23 } 236
24 }
25 320
26 } 326
27 }
28 378
29 404
30 438

ANATOMY 
Plate XXX



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