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^fe

 
 
SYSTEM
O F
ANATOMY.
"%0
 

I 
^
COMPENDIOUS  SYSTEM
O F
ANATOMY.
IN SIX PARTS.
1. OSTEOLOGY.
II.  OF THE MUSCLES, 8cc.
HI. OF THE ABDOMEN.
IV. OF THE THORAX.
V.  OF THE BRAIN AND NERVES,
VI. OF THE SENSES.
FROM THE ENCYCLOPAEDIA.
Illustrated with Twelve large Copperplates.
tooijn
PHILADELPHIA
'HAT
      PRINTED BY ARCHIBALD BARTRAM,

FOR THOMAS DOBSON, AT THE STONE HOUSE, No. 41,
          SOUTH SECOND-STREET.
1805, 
«K»l£ 
          CONTENTS.
                                      Page.
Introduction                              9
   1. History of anatomy               ibid.
   2. View of the subject in general, and
     plan of the following treatise        40

          Part I.  Osteology            57
Sect. I. Of the bones in general, with their
	appendages, &c.	58
II.	Of the bones of the head	71
1.	Bones of the cranium and face	72
2.	Proper bones of the face	85
3.	Of the teeth	91
4.	os hyoides	98
III.	bones of the trunk	99
1.	spine	ibid.
2.	bones of the thorax	108
3.	bones of the pelvis	111
IV.	Extremities	114
1.	upper extremities	115
1.	shoulder	ibid.
2.	bones of the arm	117
3.	bones of the hand	121
2.	lower extremities	124
1.	thigh	ibid.
2.	rotula, or knee-pan	126
3.	leg	127
 
                 (  vi  )
                                     Page
     4. Of the foot                     129
     4.        ossa sesamoidea          133
 Explanation of the plates of osteology 134,  152

  Part II.   Of the Soft Parts in general 157
 Of the common integuments, with their
    appendages ; and of the muscles     ibid.
 Sec. I. Of the skin                     159
     1.       scarf-skin              ibid.
     2.       rete mucosum             160
     3.       cutis, or true skin        161
     4.       glands of the skin        162
     5.       insensible perspiration and
                 sweat                 163
     6.       nails                     166
     7.       hair                     167
     8.       cellular membrane and fat  168
     II.       muscles                  170
              particular muscles        180
J ta£/<? o/YAe muscles arranged according
  to their situation                     181
Explanation of plates XXIII. XXIV. 230,233

Part III.   Of the Abdomen, or  Low-
              er Belly.                 236
Sec. I.  Of the peritoneum              238
   II         omentum                239 
                 (   vii  )
                                     Page
Sec. III. Of the stomach               241
   IV.         oesophagus             243
   P.         intestines               244
    VI.         mesentery              248
   . VII.       pancreas               251
    VIII.       liver                  253
    IX.         gall-bladder            255
    X          spleen                 258
    XL         glandule renales, kidneys
                  and ureters          259
    XII-        urinary bladder        262
    XIII  Of digestion                  266
    XIV. Of the course of the chyle and of
           the lymphatic system         278
    XV. Of the generative  organs; of
           conception, &c.              284
    1.  The male organs               ibid.
    2.  Female organs of generation      296
    3.  Of conception                   501
    4.  Of the fxtus in utero            304
 Explanation  of plates XXV.  XXVI.
   and XXVII.                    309, 316
       Part IV.   Of the Thorax       318
 See.  I Of the breasts                  319
      II.       pleura                   320
      III.      thymus                  322
      IV.      diaphragm               ibid.
      V.       trachea                   324 
                 (   viii  )
                                     Page
 Sec.  VI.  Of the lungs                  327
      VII.  Of respiration                329
      VIII. Of the voice                334
     IX.  Of dejection                  336
     X. Of the pericardium, and of the
           heart, and its auricles        337
     XL  Angiology, or a  description of
           the blood-vessels             342
     XII.  Of the action  of the  heart,
           auricles, and arteries         352
     XLII. Of the circulation            354
     XIV.        nature of the blood    355
     XV.  Of nutrition                  357
     XVI. Of the glands and secretions   359
 Explanation of plate XXVIII.           364
   Part V. Of the Brain and Nerves    366
 Sec. I.  Of the brain  and its integuments ibid.
     7/.      nerves                    379
 Explanation of plate XXIX.             386

    Part  VI.  Of the  Senses and their
                 Organs               390
 Sec. I.  Of   touch                    ibid.
     II.      taste                      391
     III.     smelling                  393
     IV.     hearing                   396
     V.      vision                     404
Explanation of plate XXX.              415 
      SYSTEM

              OF

ANATOMY.
              ANATOMY,


      THE art of dissecting, or artificially separat-
       ing  and taking to pieces,  the different
  parts of the human body,  in order to an exact
  discovery of their situation, structure, and ceco-
  nomy.—The word is Greek, avaro^j,; derived from
  «v«Ttiuv«, to  dissect, or  separate  by cutting.

         INTRODUCTION.

             1. 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 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.
                      B 
10          History of Anatomy.

  This rude knowledge  must have been gra-
dually improved, by  the  accidents  to which
the body is exposed, by the necessities of life,
and by the various customs,  ceremonies, and
superstitions, of different nations.  Thus, the
observance of  bodies killed  by violence,  at-
tention to wounded men, and to "many diseases,
the various ways of putting criminals to death,
the funeral ceremonies, and a variety of such
things, must have shown men every day more
and more of themselves; especially as  curio-
sity and self-love would  here urge them pow-
erfully 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,  be-
ing observed to be so  nearly the same in both ;
the conclusion was not only  obvious, but un-
avoidable, that their bodies were formed near-
ly upon the same  model.  And the  opportu-
nities  of examining the bodies of brutes were
so easily procured, indeed so  necessarily  oc-
curred in  the common business of life,  that
the huntsman in making use of his prey, the
priest in sacrificing,  the augur in  divination,
and, above all, the butcher, or those who might
out of curiosity  attend  upon  his operations,
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
reasoning, without the  assistance  of letters,
have  yet a considerable share of rude or wild 
            History  of Anatomy.          11

anatomical 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 bo-
dy, and something likewise of their uses ;  and
manifested a great curiosity or desire of hav-
ing 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 re-
flection, could  not overlook an instance of na-
tural  organization,  which  was  so interesting,
and at the same time so wonderful, more es-
pecially such of them  as applied to the study
and cure of diseases.  We know that physic
was a branch of philosophy till the age  of
Hippocrates.
   Thus the art must have been  circumstanced
in its beginning. We  shall next see from the
testimony  of   historians and   other writers,
how it actually appeared  as an art, from the
time that 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 lei-
sure for reflection,  and an appetite for amuse-
ment.  Accordingly, writing, and many other 
12          History of Anatomy.

useful and ornamental inventions and arts, ap-
pear 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 wri-
ters ; and that the  arts and learning of those
eastern people were in subsequent times gra-
dually communicated to adjacent countries, es-
pecially by  the medium of traffic.  The cus-
toms, superstitions, and climate of eastern coun-
tries, however, appear to have been as unfa-
vourable  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
nauseous  putrefaction,  that  the  early inha-
bitants must have avoided such offensive em-
ployments,  as anatomical inquiries, like their
posterity  at this  day.  And, in fact,  it  does
not  appear, by  the writings  of the  Greci-
ans, or Jews,  or Phoenicians, or of other eas-
tern countries, that anatomy  was particularly
cultivated by any of those eastern nations.  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
of  some  cultivation, it may be  said  to  have
been brought  forth  and bred up among them
as a  branch of natural knowledge.
  The  asra of philosophy,  as  it was called,
began with  Thales  the Milesian being declar-
ed by a very  general consent of the people,
the most wise of all the Grecians, 480 years be-
fore Christ.  The philosophers of his  school,
which was  called the Ionian,  cultivated prin- 
            History of Anatomy,           13

cipally  natural knowledge.   Socrates,  the  se-
venth in succession of their  great teachers, in-
troduced the study of morals, and was thence
said to bring down philosophy from  heaven,
to make men truly wise  and happy.
  In the writings of his scholar and successor
Plato,  we see that the philosophers had care-
fully  considered  the human body, both in its
organization  and functions ;  and  though they
had not arrived at the knowledge  of the more
minute and  intricate  parts, which  required
the successive labour  and attention of many
ages, they had made up very noble and com-
prehensive  ideas of  the  subject  in  general.
The anatomical descriptions of Xenophon and
Plato  have  had  the honour of being  quoted
by  Longinus ($xxxii.) as specimens of sub-
lime 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  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 may
be  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
speaking,  about 400 years before  the  Christi-
an  sera.  He is said to have separated the pro-
fession of philosophy and physic, and  to have 
14          History  of Anatomy,

been the  first who applied to physic alone as
the business of his life. He is likewise  gene-
rally supposed to be the first who wrote upon
anatomy.  We know of nothing that was writ-
ten 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 ac-
counts of the parts  to what we now know of
the human body, we must allow his descrip-
tions to be imperfect, incorrect, sometimes ex-
travagant, and often unintelligible, that of the
bones  only  excepted.  He seems to  have  stu-
died these with  more success than the other
parts,  and tells us that he had an opportunity
of seeing an human  skeleton.
   From  Hippocrates to Galen, who flourish-
ed towards the end of the  second century, in
the decline  of the Roman empire, that is, in
the space of 600  years, anatomy was  greatly
improved; 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 dai-
ly to the common stock, by more accurate and
extended observations, and  by the lights of
improving philosophy.
   As  these two great men had applied very
particularly to  the   study  of animal  bodies,
they not only made great improvements, es-
pecially  in physiology, but  raised the credit 
            History of Anatomy,           15

of natural knowledge, and spread  it as wide
as Alexander's empire.
  Few of Aristotle's writings were made pub-
lic  in  his lifetime.  He affected to say  that
they  would be  unintelligible to those who
had not heard them explained at  his lectures:
and, except the use which Theophrastus made
of them, they were lost to the  public for above
130 years after the  death  of Theophrastus;
and at  last came out defective from bad pre-
servation, and corrupted by men, who,  with-
out proper qualifications,  presumed  to correct
and supply what was lost.
   From  the time of  Theophrastus,  the study
of  natural knowledge at Athens  was for ever
on  the decline ; and the reputation of the Ly-
cseum and Academy  was almost confined  to
the studies  which  are subservient to  orato-
ry  and public speaking.
   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 favourite 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.   An-
atomy,  among other  sciences, was publicly
taught; and the two  distinguished  anatomists
were Erasistratus the pupil and friend of The-
ophrastus,  and  Herophilus.   Their volumi-
nous works  are all lost;  but  they are quoted
by  Galen almost in  every page.  These  pro-
fessors were probably the first who were au- 
 16          History of Anatomy.

 thorised to dissect human bodies ;  a peculiari-
 ty  which marks  strongly the  philosophical
 magnanimity of the  first  Ptolemy, and  fixes
 a great sera  in the history of anatomy. And it
 was, no doubt,  from this particular advantage
 which the Alexandrians had above all others,
 that their  school  not only gained, but for ma-
 ny  centuries  preserved,  the  first  reputation
 for  medical  education.  Ammianus Marcelli-
 nus,  who  lived  about  650  years after the '
 schools  were  set up,  says, they were so fa-
 mous 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 anato-
 mized 700 bodies. We must allow for exagge-
 ration.  Nay,  it was  said, that both he and
 Erasistratus made it a common  practice  to
open  living  bodies, 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  pro-
bable they had physicians and surgeons  from
 the  foundation  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 ac-
 count of  the  severity  of his operations.—
 Asclepiades, who flourished   in  Rome  101 
History  of Anatomy,
17
years after Archagathus, in  the  time of Pom-
pey, 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
respiration acting  by its weight; and in ac-
counting for digestion, he supposed the  food
to be no farther changed than  by a  comminu-
tion into extremely 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, physicians seem to  have been  great-
ly encouraged at Rome ; and, in the writings of
Celsus, Rufus, Pliny,  Ccelius,   Aurelianus,
and Arseteus, we  find  several anatomical ob-
servations, but mostly very  superficial  and
inaccurate.  Towards the end of the second
century lived Claudius   Gallenus  Pergamus,
whose name  is so  well known in the  medical
world.  He applied himself 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 hu-
man subjects to operate  upon; and therefore
his descriptions of the parts  are  mostly  taken
from  brute animals.  His works contain the
fullest history  of  anatomists, and the  most
                     C 
18          History of Anatomy.

complete system  of the science,  to  be met
with any where  before him,  or for several
centuries after; so that a number of passages
in them were reckoned absolutely unintelligible
for many ages, until explained by the  disco-
veries of succeeding anatomists.
  About the end of the fourth century, Ni-
mesius bishop of Emissa wrote a treatise  on
the nature 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 circula-
tion of the blood.   This last,  however,  is
proved by  Dr. Friend, in his  history of phy-
sic, p.  229. to be  falsely ascribed to  this au-
thor.
   The Roman empire  beginning now  to  be
oppressed  by the  barbarians,  and sunk   in
gross  superstition,  learning  of all  kinds de-
creased ;  and when  the empire was  totally
overwhelmed by those barbarous nations, eve-
ry  appearance of science was almost  extin-
guished 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
fluctuation 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 stu-
 dies ;  public schools were  set up at Cordova,
 Toledo, and other  towns,  and translations of 
            History of Anatomy.          19

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 never improved while they were  masters
of the  world:  for  they were  satisfied with
commenting upon Galen; and seem  to have
made no dissection 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
principal places for study in the Saracen em-
pire ; who had a favourable opinion of origin-
al observation, in opposition to book-learning ;
who boldly corrected some of Galen's  errors,
and was persuaded  that  many more might be
detected;  this man, we say,  never made or
saw, or seemed to think of a  human dissec-
tion. He discovered  Galen's errors in the oste-
ology,  by going to burying-grounds, with  his
students and others, where he examined and
demonstrated the bones ; he earnestly  recom-
mended that method of study, in preference
even to the reading of Galen, and  thought that
many farther  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 Ma-
hometans  adopted,  about  uncleanliness and
pollution,  might  prevent  their handling dead
bodies ; or their opinion  of what  was  suppos- 
20          History of Anatomy.

ed  to pass between an angel  and the dead
person, might make them think disturbing the
dead  highly sacrilegious.   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  restora-
tion of learning in the end of the 15th centu-
ry.  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
extracted  principally from what the Arabians
had preserved of Galen's doctrine ; and, rude
as it is, 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 continu-
ed  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, how-
ever,  prevailed  till  the 16th century.   The
emperor 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  Muscovy, till very lately,  both  anatomy
and the use of skeletons were  forbidden, the
first as inhuman,  and the latter as subservi-
ent to witchcraft. 
            History of Anatomy.          21

   In the beginning of the 15th century, learn-
ing revived considerably in Europe, and par-
ticularly physic,  by means  of copies  of  the
Greek authors brought from the sack of Con-
stantinople ; after which the number of anato-
mists and anatomical books  increased to a pro-
digious degree.—The  Europeans  becoming
thus  possessed  of the ancient Greek  fathers
of medicine, were  for a  long time so much
occupied in correcting the  copies  they could
obtain,  studying the meaning, and comment-
ing upon them,  that they  attempted nothing
of their own, especially in anatomy.
   And here the late Dr. Hunter  introduces
into the annals of this art, a genius of the
first rate, Leonardo da Vinci, who had been
formerly overlooked, because he was  of ano-
ther profession,  and because he published no-
thing upon the subject.  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 prac-
tice of making anatomical drawings.
   Vassere, in his lives of the  painters, speaks
of Leonardo thus,  after telling us that he  had
composed a book of the anatomy of a horse,
for his own study:  "He afterwards  applied
himself with more  diligence to the human an-
atomy ; in  which study he reciprocally receiv-
ed and communicated assistance to  Marc. An-
tonio  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 
 22          History of Anatomy,

 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 himself dissected;
 where he made all the bones, and to those he
 joined, in  their order, all the nerves,  and co-
 vered them with the muscles.  And concern-
 ing those,  from part to part, he wrote remarks
 in letters of an ugly form, which are  written
 by the left hand, backwards, and not to be un-
 derstood but by those  who know  the  method
 of reading them; for they are not to  be read
 without a  looking-glass.   Of these  papers 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  Le-
 onardo, was a  most  beautiful boy, and much
 beloved by him, as he is now a beautiful  and
 genteel old  man,  who  reads those  writings,
 and carefully preserves them, as precious  re-
 licks, together  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. ckc."
  Those very  drawings  and the writings are
happily found  to be preserved in his  Britan-
 nic Majesty's great collection of original draw-
ings, where the Doctor was permitted  to exa- 
            History of Anatomy.         23

mine them ; and  his sentiments upon the oc-
casion he thus expresses : " I expected to see
little more than  such designs in anatomy, as
might be  useful  to a painter in his own pro-
fession ;  but I saw, and indeed with astonish-
ment, that Leonardk) had been a general and a
deep student.  When I consider what pains he
has taken upon every part of the body, the su-
periority of his universal genius, his particular
excellence in mechanics and  hydraulics,  and
the attention with which such a man would ex-
amine and see  objects which he was to  draw,
I am fully persuaded that Leonardo was the
best anatomist at that time in the world.   We
must give the 15th century the credit of Leo-
nardo'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 improve-
ment of anatomy in Italy, where they taught
it, and published  upon the  subject.  These
first improvers  made  some  discoveries  from
their own dissections :  but it  is not  surprising
that they should  have been diffident of them-
selves, and have followed Galen almost  blind-
ly, when his authority had been so long  estab-
lished, 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
Brussels, the  place of  his birth, he  went to
Louvain, and thence to Paris, where anatomy 
24          History of Anatomy.

was not yet making a considerable figure, and
then to Louvain to teach; from which place,
very fortunately for his reputation, he was call-
ed to Italy,  where he met  with  every oppor-
tunity  that  such a genius for anatomy could
desire, that is, books,  subjects,  and excellent
draughtsmen.  He was  equally laborious in
reading the  ancients, and in dissecting bodies.
And in making the comparison,  he  could not
but see, that there was great room for improve-
ment, and that many of Galen's descriptions
were erroneous.   When he was but a young
man, he published a noble system of anatomy,
illustrated with  a great number of elegant fi-
gures.—In this work  he found so many  occa-
sions of correcting Galen,  that his  contempo-
raries,  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 Sylvius  in France,
Columbus, Fallopius, and Eustachius in Italy,
who were all in high  anatomical  reputation
about the middle of this 16th century, endea-
voured to  defend Galen at the expense of Ve-
salius.   In their disputes they made their ap-
peals to the human body: and thus in a few
years the art was greatly improved.   And Ve-
salius  being detected in the very fault which
he condemned  in Galen,  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 
            History of Anatomy.         25

complaint.—Besides the above, he published
several other anatomical treatises.   He  has
been   particularly  serviceable  by  imposing
names on the muscles, most of which are re-
tained to  this day.  Formerly they were dis-
tinguished by numbers, which were  different-
ly applied by almost every author.
   In   1561, Gabriel  Fallopius, professor  of
anatomy at Padua,  published a treatise of ana-
tomy  under the title of Observations Anatomi-
es.   This  was designed as a supplement to
Vesalius ; many of whose descriptions he cor-
rects,  though he always makes mention of him
in  an honpurable  manner.  Fallopius made
many great  discoveries, and his book is well
worth the perusal of every anatomist.
   In   1563,  Bartholomseus  Eustachius  pub-
lished his Opuscula Anatomica at Venice, which
have  ever since been justly admired for the ex-
actness of the descriptions, and the discove-
ries contained in them.  He published after-
wards some other pieces, in which there is lit-
tle of anatomy ; but never published the great
work  he had promised, which was to be adorn-
ed 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  phy-
sician ; who added a short explicatory text, be-
cause  Eustachius's own writing could not be
found.
   From this time the study of anatomy gradu-
ally diffused itself over Europe ; insomuch that
                    D 
26            History of Anatomy.

for the last hundred years it has been daily im- *
proving by the labour of a number of profes-
sed 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 Corte-
sius.  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 fi-
nish a treatise which he  had begun on practi-
cal 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 expected to have done
so, he says, once every year, according to the
custom in the famous academies  oj Italy.
   In the very end of the  16th century, 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 beginning of the 17th century, soon after
Harvey's return to England,  his master in ana-
tomy, Fabricius  ab Aquapendente,  published
an account of the valves in the  veins, which
he had discovered many years before,  and no
doubt taught in his  lectures when Harvey at-
tended him.
   This discovery evidently affected  the estab-
lished doctrine  of all ages, that the veins car-
ried 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 
            History of Anatomy.           27

in animals;  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,  lie taught his ne\v 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 bo-
dies  in any age.  It not only reflected useful
lights upon  what had been  already  found  out
in anatomy,  but also pointed out the means of
further investigation.  And accordingly  we see,
that  from Harvey to the present time, anato-
my has been so much improved,  that we may
reasonably question if the ancients  have been
further outdone by the moderns in any other
branch of knowledge.  From one day  to ano-
ther there has  been a constant  succession of
discoveries,  relating either to the structure or
functions  of our body ;  and new anatomical
processes, bo,th of investigation and  demon-
stration,  have  been  daily invented.   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 cir-
culation.
  Harvey's  doctrine at first met  with conside-
rable opposition ; but  in the space of about 20
years  it was so generally and  so warmly em-
braced, that it  was imagined every thing in
physic would be explained.  But time and ex- 
28           History of Anatomy.

perience have taught us, that we still are, and
probably must long continue to be, very igno-
rant ;  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  the nutritious part of  the food or
chyle from the  bowels to the  blood-vessels:
And,  by good fortune, 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 intes-
tines ; 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 pub-
lications, the anatomists in all parts of Europe
were  daily opening living dogs,  either to see
the lacteals  or to observe the phenomena of
the circulation.   In making an  experiment of
this kind,  Pecquet  in  France  was fortunate
enough to discover the  thoracic duct, or com-
mon trunk of all  the lacteals, which conveys
the chyle into the subclavian vein.  He print-
ed  his discovery in the  year 1651.  And now
the lacteals having been traced from the intes-
tines  to the thoracic duct, and that  duct having
been  traced to its termination in  a blood-ves-
sel, the passage  of the chyle was completely
made out.
  The  same  practice of opening living animals
furnished occasions of discovering  the lympha- 
History of Anatomy.
22
tic  vessels.   This  good  fortune fell  to the
lot of Rudbec first,  a young Swedish  anato-
mist ; and then to Thomas Bartholine,  a Da-
nish anatomist, who was the first who appear-
ed  in print upon the lymphatics.   His book
came out in the year 16 53,  that is,  two years
after that of Pecquet. And then it was very evi-
dent that they had been seen before by Dr. Hig-
more and others, who had mistaken them for
lacteals.  But none of the anatomists of those
times could make out the  origin of the lym-
phatics, and none of the  physiologists  could
give a  satisfactory account of their use.
   The  circulation of the  blood, and the pas-
sage of the chyle  having  been satisfactorily
traced out in full-grown  animals, the  anato-
mists were naturally 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 ute-
rus, the incubated  egg, and every  phenome-
non which could illustrate generation, became
the favourite subject, for about 30 years, with
the principal anatomists of Europe.
   Thus it would appear to have been in theo-
ry :  but Dr. Hunter believes,  that in fact,  as
Harvey's master Fabricius laid the foundation
for  the discovery  of the circulation of the
blood by teaching him the  valves of  the veins,
and thereby inviting him to consider that sub-
ject ;  so Fabricius by his lectures, and by his
elegant  work De formato fcetu, et deformatione
avi et pulli,  probably made that likewise a fa- 
 30          History of Anatomy.

 vourite subject with Dr.  Harvey.   But whe-
 ther he took up the subject of generation  in
 consequence of his discovery  of the circula-
 tion, or was led to it by his honoured master
 Fabricius,  he spent a great deal of his  time
 in the inquiry; and published his observations
 in a book  De generatione  animalium, 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 at-
 tention to  the subject  of  generation, by their
 supposed discovery that the females of vivipa-
 rous 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
 subject of  generation.  He  had the good for-
 tune to be the first who used magnifying glass-
 es with address in tracing the first appearances
in the formation of  animals. He likewise made
many other observations and improvements in
the minutie of anatomy by his microscopical la-
bours,  and by cultivating comparative anato-
 my.
   This distinguished anatomist gave the  first
public  specimen of  his abilities, by printing a
dissertation 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. 
           History  of Anatomy.          31

  At the  same time  flourished  Laurentius
Bellinus at Florence, and  was the  first  who
introduced mathematical  reasoning  in physic.
In 1662, Simon Pauli published a treatise De
albaudis  ossibus.  He  had  long been admired
for  the  white skeletons  he prepared;  and at
last discovered his method,  which was by ex-
posing the bones all winter to the  weather.
  Johannes Swammerdam of Amsterdam also
published some  anatomical treatises ; but was
most  remarkable for his knowledge of  pre-
serving the parts of bodies entire for many
years, by  injecting their vessels.  He  also
published  a treatise on respiration;  wherein
he  mentioned his having  figures of  all the
parts of the body  as big as the  life,  cut  in
copper,  which  he  designed to publish,  with a
complete systems of anatomy.  These, howe-
ver, were never  made public by Swammerdam;
but,   in  1683,  Gothofridus  Bidloo, professor
of anatomy at Leyden, published a work en-
titled Anatomia corporis humani, where  all the
parts were delineated in very  large plates al-
most as  big as the life.  Mr. Cowper, an Eng-
lish  surgeon,  bought 300  copies of these  fi-
gures; and in 1698, published them with an
English text, quite different from Bidloo's La-
tin one ;  to which were added letters in  Bid-
loo'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,  e died Gulielmus Cowperus  citatus 
32          History of Anatomy.

coram tribunali;  appealing to the Royal Soci-
ety, how far Cowper ought to  be punished
as a plagiary of the worst  kind, and  endea-
vouring to prove him an  ignorant  deceitful
fellow.   Cowper answered  him in  his  own
style, in a  pamphlet called his Vindicia; en-
deavouring  to prove, either that Bidloo  did
not understand his own tables,  or that  they
were  none of his.  It was  even alleged that
those were the tables  promised  by  Swam-
merdam, and which Bidloo had got from his
widow.   This,  however, appears to have been
only  an invidious  surmise, there being  un-
questionable evidence that they were really
the performance of Bidloo.
   Soon after, Isbrandus Diembroeck,  profes-
sor  of  anatomy at Utrecht, began to  appear
as an author.  His work contained very little
original; but he was at great pains to collect
from others whatever  was valuable in their
writings,  and his system  was  the common
 standard among  anatomical students for ma-
 ny years.
   About the same time,  Antonius Liewen-
 hoeck  of  Delft,  improved considerably  on
 Malpighi'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 enabled to see the actual  circula-
 tion of the blood  in  the transparent parts of
 living  animals,  and could  measure the velo-
 city  of its motion; they discovered that  the 
            History of Anatomy.          33

arteries and veins had no  intermediate cells
or spungy substance,  as  Harvey  and all the
preceding anatomists had supposed, but com-
municated one with the other by  a continua-
tion  of the same tube.
  Liewenhoeck was in great fame likewise
for his discovery of the animalcula in the se-
men. Indeed there was scarcely a part of the
body, solid or fluid, which escaped his examina-
tion ; and he almost every where  found,  that
what appeared to the naked eye to be rude un-
digested matter, was in reality a beautiful and
regular compound.
  After this period,  Nuck added to our know-
ledge of  the absorbent system  already men-
tioned,  by  his  injections   of the  lymphatic
glands;  Ruysch,  by  his  description of the
valves of the  lymphatic  vessels; and  Dr.
Meckel, by his accurate account of the whole
system, and by tracing those vessels in many
parts where  they had not before been de-
scribed.
  Besides these authors,   Drs.  Hunter  and
Monro have called  the attention  of the pub-
lic  to this part of anatomy, in their  contro-
versy concerning the  discovery of the office
of the lymphatics.
  When the lymphatic vessels were first seen
and traced into the thoracic duct,  it was natu-
ral for anatomists to suspect, that as  the lac-
teals  absorbed from the  cavity of  the intes-
tines, the  lymphatics,  which are similar in
figure  and  structure,  might possibly do the
same office with respect to other  parts of the
                     E 
34          History of Anatomy.

body:  and accordingly,  Dr.  Glisson, who
wrote in  16 54,  supposes these vessels arose
from cavities, and that their use was to ab-
sorb ; and Frederic Hoffman has very expli-
citly laid  down  the doctrine of the lymphatic
vessels  being a system of absorbents.   But
anatomists in general have been  of a contra-
ry opinion; for,  from experiments,  particular-
ly 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 ar-
teries.   The doctrine, therefore,  that the lym-
phatics, like  the lacteals, were absorbents, as
had been suggested by Glisson  and by Hoff-
man, has been revived by Dr. Hunter and Dr.
Monro, who  have  controverted  the  experi-
ments  of their predecessors in anatomy,  and
have endeavoured to prove that the lympha-
tic  vessels are  not  continued  from  arteries,
but are absorbents.
  To this doctrine, however,  several objec-
tions have been started, particularly by Hal-
ler  (Elem. 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 discover-
ing the lymphatic  system in birds, fish, and
amphibious animals.   See Phil.  Trans,  vol.
Iviii. and lxix.—And latterly, Mr. Cruikshank 
             History  of Anatomy.          3 5

 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. Sheldon also
 we are  much  indebted for  his  illustration of
 this system,  which promises to give great sa-
 tisfaction, but  of which only  a  part  has yet
 been published.
   The  gravid  uterus is  a  subject  likewise
 which  has  received  considerable  improve-
 ments, particularly  relating to one  very  im-
 portant discovery; viz. that  the internal mem-
 brane of the uterus,  which Dr. Hunter  has
 named  decidua,  constitutes  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 mis-
 carriage.  This discovery includes another, to
 wit, that the placenta is partly made up of an
 excrescence  or  efflorescence from the uterus
 itself.
   These discoveries  are of  the utmost conse-
 quence,   both  in the  physiological  question
 about the connection  between the mother and
 child, and likewise in explaining the phenome-
 na of births  and abortions,  as well as in re-
 gulating obstetrical practice.
   The anatomists  of this century  have  im-
 proved anatomy, and  have made the study of
 it  much more easy, by giving us more correct
 as well as more numerous figures.  It is amaz-
ing 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,  Albi- 
36          History  of Anatomy.

nus's, Sue's and Trew's.   Of the muscles, we
have had two large folios; 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.  Iialler.   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 up-
on the  pregnant uterus; Weitbrecht and Le-
ber on the  joints and fresh  bones; Soemer-
ring on the brain; Zin on the eye; Cotunius,
Meckel junior, &.c.  on the ear;  Walterus on
the nerves of the thorax and abdomen; Dr.
Monro on the bursse mucosas,  he.
  It would  be endless to mention the anato-
mical figures that have been  published in this
Gentury, of particular and smaller parts of the
body, by Morgagni,  Ruysch, Valsalva,  Sanc-
torini,  Heister,  Vater,  Cant,  Zimmerman,
Walterus, and others.
  Those elegant  plates of the  brain, howe-
ver, just published by M. Vicq.  d'Azyr,  must
not pass  without notice, especially as  they
form part of an universal system of anatomy
and physiology, both human and comparative,
proposed to be executed in the same splendid
style.  Upon 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 beauti-
ful than correct.  Such parts of this work as
may be published, cannot fail to be equally 
            History  of Anatomy.          37

acceptable  to  the anatomist  and the philoso-
pher; but  the  entire design  is apparently too
extensive to be accomplished within the peri-
od 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
inspection  of his very ingenious assistant Mr.
Fyfe.  It is  to compose  a complete illustra-
tion, both  general and particular, of the hu-
man body,  by  a selection from the best plates
of all the greatest anatomists, as well foreign
as British, exhibiting the latest discoveries in
the science, and accompanied with copious ex--
planations.   The  whole  number of  plates
mentioned  in the Prospectus is 240,  of which
152 are already done; all in royal folio,
  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, Doug-
las,  Cheselden,  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 students of anatomy: but
it  has of  late  given place  to  a more  accu-
rate  and comprehensive system, in  three vo-
lumes, published by Mr. Elliot of Edinburgh,
upon  a  plan   approved of  by  Dr. Monro,
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 Ana- 
 38          History of Anatomy.

 tomy and the Animal Oeconomy:" in which
 the subjects are treated with  uncommon ele-
 gance and perspicuity.
  In the latter part of the last century,  ana-
 tomy made two great steps, by the invention
 of injections, and the method of making what
 we  commonly call preparations.  These two
 modern arts have  really been of infinite use
 to anatomy; and  besides have introduced an
 elegance into  our  administrations,  which  in
 former times could  not have  been supposed
 to be possible.  They  arose in Holland un-
 der  Swammerdam and  Ruysch,  and after-
 wards  in England under Cowper, St. Andre,
 and others, where they have been greatly im-
 proved.
  The anatomists of former ages had no other
 knowledge  of the  blood-vessels,  than what
 they were able to collect from laborious dis-
 sections, and  from examining  the  smaller
 branches of them,  upon some  lucky occa-
 sion, when they were  found more than com-
 monly  loaded with red blood.   But filling
 the  vascular system with a bright coloured
 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 natu-
ral 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  same time  so ornamental, that  it 
            History  of Anatomy.          39

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  co-
lours,  and   so  very incorrect  in the circum-
stances of figure, situation,  and the like, that
though they strike a vulgar eye with admira-
tion, they must appear ridiculous to an ana-
tomist.  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
insignificant  acquisition to modern anatomy.
The proper, or principal use of this art is, to
preserve a  very perfect likeness of such sub-
jects as we but seldom  can  meet with, or can-
not well preserve in  a natural state; a subject
in pregnancy, for example.
   The modern improved methods  of preserv-
ing animal  bodies, or parts of  them, has been
of the greatest service to  anatomy; especially
in saving the time and labour of the  anato-
mist  in  the nicer  dissections of the  small
parts of the  body.   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 ana-
tomical curiosities,  or rarities  of  every kind;
such as, parts that are uncommonly formed ;
parts that are diseased; the parts of the preg. 
40        Introduction to Anatomy.

nant uterus and its  contents.  Large collec-
tions  of such curiosities, which modern ana-
tomists  are striving almost every where  to
procure, are  of infinite service to  the art,  es-
pecially in the hands of teachers.  They give
students clear ideas about many things which
it is very essential to know, and yet which it
is impossible that  a teacher should be able to
show otherwise, were he ever so well suppli-
ed with fresh subjects.

            --------  '■■HiiiHJlJii

2.  View of the Subject in general, and Plan of
           the following Treatise.

  THE etymology of the  word anatomy, as
above given,  implies simply dissectio7i; but by
this term something more  is usually under-
stood.
  It  is  every day made use  of to express a
knowledge of the human body ; and a person
who is  said  to understand anatomy,  is sup-
posed 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  hu-
man body; the latter includes all  animals> so
far  as a knowledge of their structure may tend
to perfect our ideas of the human body. 
          Introduction to Anatomy.        41

   The term anatomy may also  have another
and more  extensive  signification: it may  be
employed to express not only a knowledge of
the structure and disposition of  the  parts but
likewise of their oeconomy and use.  Consider-
ed in this light, it will seldom fail to  excite the
curiosity of people of taste, as  a branch  of
philosophy; since if it is pleasing  to be ac-
quainted 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 mechanism  by
which so many  different  functions  are exe-
cuted.
   Astronomy and  anatomy, as Dr. Hunter,
after Fontenelle,  observes,  are  the studies
which present 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 number of the heavenly bodies ;
the  last, astonishes  with his intelligence  and
art in the variety and delicacy of animal  me-
chanism.
   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 Crea-
tor ; and abounds with  as irresistible  proofs
of a  supreme Cause  and governing  Provi-
                      F 
 42         Introduction to Anatomy.

 dence, as we find in modern physico-theology.
 And Cicero dwells  more on the structure and
 ceconomy of animals than on all the produc-
 tions  of nature besides,  when he  wants to
 prove  the existence of the  gods from the or-
 der and beauty of the universe.    He there
 takes a survey of the body of man in a most
 elegant synopsis of  anatomy,  and concludes
 thus: " Quibus rebus expositis, satis docuisse
 videor,  hominis natura, quanto omnes anteiret
 animantes.  Ex quo debet intelligi,  nee  figu-
 ram situmque  membrorum, nee ingenii men-
 tisque vim talem effici potuisse fortuna."
  The satisfaction of mind which arises from
 the study of anatomy, and the influence which
 it must naturally have upon our minds as phi-
 losophers,  cannot be better conveyed than by
 the following passage from the same author:
 " Quse contuens animus, accepit ab his cogni-
 tionem deorum, ex qua oritur pietas: cui con-
juncta justitia  est,  reliquseque  virtutes: ex
 quibus vita beata exsistit, par et similes deo-
 rum,  nulla  alia re nisi immortalitate, quse ni-
 hil ad bene  vivendum pertinet, cedens cceles-
 tibus."
  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 func-
tions of animals with a view towards the Cre-
 ator.  It is a view which must strike one with
 a most awful conviction.  Who can know  and
consider the thousand evident proofs of the as-
tonishing  art of the   Creator,  in forming  and 
           Introduction to Anatomy.        43

 sustaining an animal body such as ours,  with-
 out feeling the most pleasant enthusiasm ? Can
 we seriously reflect upon this awful subject,
 without being almost  lost in adoration ?  with-
 out longing for another life after this, in which
 we may be  gratified  with the highest enjoy-
 ment, which our faculties and nature seem ca-
 pable of, the seeing and comprehending the
 whole plan of the Creator, in forming the uni-
 verse and in directing  all its operations ?
   But the more immediate purposes of anato-
 my concern those who  are to be the guardians
 of health,  as this study is necessary to  lay a
 foundation for all  the branches of medicine.
 The  more we know of our fabric,  the  more
 reason  we have to believe, that if our senses
 were  more acute, and  our judgment  more en-
 larged,   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 there-
 by be enabled to restore the health of many,
 who are now, from our more confined know-
 ledge, said  to  labour  under incurable disor-
 ders.   By such an intimate acquaintance  with
 the ceconomy of  our bodies, we should disco-
 ver even the seeds of diseases, and destroy
 them  before  they had taken  root in the consti-
 tution.
   That anatomy is the very basis of surgery
 every 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 
U        Introduction to Anatomy.

delicacy; and where  we must not, upon any
account,  attempt 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  fel-
low-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 arrive at the knowledge  of the  true nature
of most of the diseases which afflict humanity.
The symptoms of  many  disorders are often
equivocal; and diseases themselves are thence
frequently  mistaken,  even by sensible, expe-
rienced, and attentive  physicians.  But by ana-
tomical examination after death, we can with
certainty find out the mistake,  and learn  to
avoid it in any  similar case.
   This use of  anatomy has  been so generally
adopted by  the moderns, that the cases alrea-
dy published are almost innumerable: Man-
ge tus, Morgagni, indeed many of the best mo-
dern writings in physic, are full of them. And
if we look among the physicians  of  the best
character, and observe those who have  the
art itself, rather than  the craft of  the profes-
sion at heart;  we shall find them  constantly
taking pains to procure leave to examine the
bodies of their  patients after death.
   After having considered the rise and pro-
gress 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 
            Introduction to Anatomy.       45

importance of the study, not only for the pre-
vention and cure of diseases, but in furnish-
ing 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 com-
plication of nice  and tender machinery ? Why
was there  not rather a more simple, less deli-
cate,  and less expensive frame ?*
   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 corporeal 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 inquiry,  we shall
plainly see the  necessity or  advantage, 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 answer
some of the requisites, human wit and inven-
tion 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 sen-
  * The following beautiful representation is taken from the late
Dr. Hunter's Introductory Lecture in Anatomy. 
46        Introduction to Anatomy.

ses 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, imma-
terial agent,  must be  provided with a place of
immediate residence,  which shall have all the
requisites for the union of spirit and body ;
accordingly she is  provided with  the  brain,
where she dwells as governor and superintend-
ant of the whole fabric.
  In the next place, as she is to hold a corre-
spondence 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  provided  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 or-
gans of communication between herself in the
brain and those organs of  sense, to give her
information  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 com-
mands 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  dis-
perse themselves in branches through all parts
of the body.  They  convey all the different
kinds of sensations to the  mind, in the brain; 
          Introduction to Anatomy,        47

and likewise carry out from thence all her com-
mands or influence to the other parts of the
body.  They are intended to be occasional mo-
nitors against all such impressions as might en-
danger 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 many disagreeable  and painful sensa-
tions which we are exposed to from a thousand
accidents in life.
  Moreover, the mind, in this  corporeal sys-
tem, must be endued with the power of mov-
ing from place to place, that she may have in-
tercourse with  a variety of objects ; that she
may fly from such as are disagreeable, danger-
ous  or hurtful,  and pursue such as are plea-
sant or useful to her.   And accordingly she is
furnished with  limbs, and with  muscles  and
tendons, the instruments of motion, 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
proper.places ; to give fixed points for, and the
proper 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. 
 48        Introduction to Anatomy.

  These pieces must all be firmly bound toge-
 ther,  to  prevent their dislocation.  And this
 end is perfectly well  answered by  the liga-
 ments.
  The extremities  of these bony pieces, where
 they  move and rub  upon one  another, must
 have  smooth and  slippery surfaces  for easy
 motion.  This is most happily provided for,
 by the cartilages 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 adi-
 pose substance.
  There must  be  an outward  covering over
 the whole apparatus, both to  give it  compact-
 ness 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 sen-
sible marks or signs ; which shall be both easy
to herself, and admit of great variety; and ac-
cordingly she is provided with the organs and
faculty of speech, by which she  can throw out
 signs with amazing facility, and vary them with-
out 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 work- 
           Introduction to Anatomy.        49

 ed 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.  There-
 fore a treasure of blood is actually  provided in
 the heart and vascular system, full of nutritious
 and healing 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 ad-
 vantage of the heart and arterial system.
   What  more there was of this  blood  than
 enough to repair the present damages  of the
 machine, must not be lost, but should be re-
 turned again to the heart;  and for this purpose
 the venous system is actually provided.  These
 requisites in the  animal explain, a priori, the
 circulation of the blood.
   The old materials which were become  use-
 less,  and are swept off by the current of blood,
 must be separated and thrown  out  of the sys-
 tem.   Therefore glands, the organs of  Secre-
 tion, are given for straining whatever is redun-
 dant,   vapid, or  noxious, from  the mass of
 blood;  and when strained, they are thrown
 out by emunctories,  called organs of Excre-
 tion.
   But now, as the machine must be constant-
ly wearing, the reparation must be carried on
without intermission, and  the strainers must
always be employed.   Therefore there  is ac-
                     G 
50        Introduction  to Anatomy.
tually a perpetual 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 consumed, and the fabric would break
down,  if there were  not a provision made for
fresh supplies.   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
converted into blood.  Therefore  she is pro-
vided with teeth for  cutting and bruising the
food, and with a stomach for melting it down:
In short, with all the organs subservient to di-
gestion.—The finer parts  of the  aliments only
can be useful in the constitution:  these  must
be taken up and conveyed into the blood, and
the dregs must be thrown off.  With this view
the intestinal canal is actually given.  It  sepa-
rates the nutritious part, which  we call chyle,
to be conveyed into  the blood by the system
of absorbent vessels; and the fseces pass down-
wards, to be conducted out of the body.
  Now we have got our  animal  not only fur-
nished with what is wanted for  its immediate
existence, but also with the powers of protract-
ing that existence to an  indefinite length of
time. But its duration, we may presume,  must
necessarily be limited: for as  it is nourished, 
          Introduction to Anatomy.        51

grows, and is raised up to its full strength and
utmost perfection ; so it must, in time, in com-
mon with all material beings, begin to decay,
and  then hurry on to final ruin.   Hence we
see the necessity of a scheme for renovation.
Accordingly  wise Providence, to perpetuate,
as well as preserve his work, besides giving a
strong appetite for life and  self-preservation,
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
survey which human reason is able to take of
this  subject,  the animal man must necessarily
be complex in his corporeal system, and  in its
operations.
   He must have one great and general system,
the vascular, branching through the whole for
circulation:  Another the nervous, with its ap-
pendages the organs of sense, for every kind
of feeling:  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 confined:  One  for strength,  support, and
protection; the bony compages : Another for
the requisite motions of the parts among them-
selves, as well as for moving from  place to
place ; the muscular  part of the body: Ano-
ther  to prepare nourishment  for the  daily re-
cruit of the  body; the digestive organs :  And
one for propagating the  species; the organs of
generation. 
52        Introduction to Anatomy,

  And in taking  this general  survey of what
would  appear,  a priori,  to  be necessary for  '
adapting 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, except the  organs of respira-
tion.  Breatning it seemed 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 bo-
dy,  and their functions, so well accounted for,
and so  wisely adapted to their several purpo-
ses, there could be no  doubt  that respiration
was so likewise: And accordingly, the disco-
veries  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
body, the use and necessity are not  more ap-
parent, than the wisdom and contrivance which
has been exerted  in putting them all into the
most compact and convenient form : in dispos-
ing 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 success-
fully  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;
suppose the  best  constructed  ship  that ever
was built, we  shall be convinced beyond the 
           Introduction to Anatomy.        S3

possibility of doubt, that there are  intelligence
and power  far  surpassing what humanity can
boast of.
  One  superiority in the natural  machine is
peculiarly  striking.—In  machines of  human
contrivance 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 admits of repair.  But in  the  natural
machine, the animal body, this is most won-
derfully 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 itself;  a  broken
bone is made firm again  by  a callus ;  a  dead
part is separated and thrown off; noxious juic-
es are driven out by some of the emunctories;
a redundancy  is removed by some spontane-
ous bleeding ; a bleeding naturally stops of it-
self; and a great loss of blood, from any cause,
is in some measure compensated, by a con-
tracting power in  the vascular system, which
accommodates  the capacity of the vessels to
the quantity contained.  The  stomach gives
information when the supplies have  been ex-
pended ; represents, with great exactness, the
quantity and the quality of what is wanted in
the present state of the  machine ;  and in pro-
portion as  she meets with neglect,  rises in her
demand, urges her petition in a louder tone,
and  with more forcible arguments.   For its 
 54       Introduction to Anatotny..

 protection, an animal body resists heat and
 cold in a very  wonderful manner, and pre-
 serves an equal temperature in a burning and
 in a freezing atmosphere.
   A farther  excellence or superiority in the
 natural machine, if possible, still more aston-
 ishing,  more beyond  all human comprehen-
 sion, than what we  have been speaking  of, is
 the following.  Besides those internal powers
 of self-preservation  in each  individual, when
 two of them co-operate, or act in concert, they
 are endued with powers of making  other ani-
 mals or machines like themselves, which  again
 are possessed of the same powers  of produc-
 ing others,  and so of multiplying the species
 without end.
   These are powers which mock all human in-
 vention or imitation.  They are characteris-
tics 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
noticed, is commonly divided into  two parts.
The first, which is called Anatomy, relates to
the matter and structure  of its parts; the se-
cond, called Physiology and  Animal ozconomy,
relates to  the principles and  laws of its inter-
nal operations and functions.
   As the body  is a compound of  solids and
fluids,  Anatomy is divided into,
   1. The Anatomy  of the solids, and
   2. The Anatomy of the fluids. 
          Introduction to Anatomy.         55

   I. The Solids, by which we mean all parts
of our body,  which are not fluid, are general-
ly 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
observation,  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,
   (l.) 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 bow-
els.   There is, besides, that part which treats
of the organs of sense and of the integuments.
   This division  of the solids has been here
mentioned, rather for  the sake of explaining
so many  words, which are  constantly used
by anatomists, than for its importance or ac-
curacy.   For besides  many  other objections
that  might be urged, there are in the body
three  species of solids, viz.  gristle  or carti-
lage,  hair, and  nails ;  which are of an inter-
mediate  nature  between bone and flesh; and
therefore  cannot so properly be brought into
the osteology or  the  sarcology.  The  cartila-
ges were classed  with the bones ; because  the 
56        Introduction to Anatomy.
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 surfaces 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 dif-
ficult 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
connections and reciprocal influence, that they
cannot well be understood or explained sepa-
rately.   In this sense our body may be  com-
pared to a circular chain of  powers, in which
nothing is first or last, nothing solitary or in-
dependent ;  so that  wherever  we  begin, we 
Osteology,
57
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,
without 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, supposed the existence of both the heart
and brain: Wherefore we shall incorporate the
Physiology with the Anatomy, by attempting
to explain the functions after we have demon-
strated the organs.
         Part I.  OSTEOLOGY.

       E begin with the bones, which may be
        considered as the great support of the
body, tending to  give it shape and firmness.—
But before we enter into the detail of each par-
ticular bone,  it will be necessary  to describe
their composition and connections, and to ex-
plain  the nature  of the different parts which
have an immediate relation to them; as the car-
tilages,  ligaments,  periosteum,  marrow, and
synovial glands.
                     H
w 
58
Osteology.
Sect. I.  Of the Bones  in general, with their
              Appendages,  &fc.

  The  bones are of  a firm and  hard*  sub-
stance,  of a white colour, and perfectly insen-
sible.   They are  the  most  compact and solid
parts of the body,  and serve  for the attachment
and support of all the  other parts.
  Three different substances  are  usually dis-
tinguished in them;  their   exterior  or  bony
part, properly so  called; their  spongy cells;
and their reticular substance.  The first of these
is formed of many laminae or plates, compos-
ing a firm  hard substance—The spongy  or
cellular part is so called on account  of its re-
semblance to a sponge,  from  the little cells
which compose it.   This substance forms al-
most the whole of the  extremities of cylindrical
bones.  The reticular part  is composed of fi-
bres, which cross  each other in different direc-
tions.   This net-work forms the internal sur-
face of those bones which have cavities.
  The  flat bones, as those  of the  head,  are
composed only of the  laminae  and the cellular
substance.  This  last is usually found in the
middle of the bone dividing it into two plates,
and is there called diploe.


  * Mr. Scheele has lately difcovered that bones contain the
phofphoric acid united with calcareous earth; and that to this
combination they owe their firmnefs. 
Osteology.
59
   Gagliardi, who pretended to have discover-
ed an infinite  number  of claviculi*  or bony
processes,  which he describes as traversing
the laminae to unite  them together, has endea-
voured to support this pretended discovery by
the  analogy of bones to the bark of trees, in
which certain  woody nails have been remark-
ed;  but this  opinion seems  to  be altogether
fanciful.
   Some  writers  have  supposed, that  the
bones are formed by layers of the perioste-
um, which gradually ossify, in the same man-
ner  as the timber is formed  in  trees by the
hardening of the 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 ordi-
nary food alternately during a  certain time;
and he asserts, that in dissecting their bones,
he constantly observed  distinct  layers of red
and white, which corresponded with the length
of time  they had lived on madder  or their
usual aliment.   But it has since  been proved
by Detleff, that  M. Duhamel's  experiments
were inaccurate,  and that neither the perios-
teum 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

  * In his Anat. Ojfium tiov. invent, dlujlrat. he defcribes four
kinds of thefe claviculi or nails, viz. the perpendicular, oblique,
headed, and crooked. 
60
Osteology.
name of diaphysis to the body or middle part,
and divided the extremities into apophysis and
epiphysis.  An  apophysis, or process, as it
is more commonly called, is an eminence con-
tinued from the body 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 tue foetus, afterwards become apophy-
ses ; for they are at length so completely unit-
ed to the body of the bone as  not to be distin-
guishable 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  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 proces-
ses, 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 processes of the os femo-
ris  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 theso
foramina are sometimes termed canals  or  con-
duits, according  to their form and extent.   Of
the depressions,  some  are useful  in  articula-
tion.  These are called cotyloid when they are 
Osteology,
61
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 receives the os humeri.  Of
the depressions that are not designed for arti-
culation, those which have small apertures are
called sinuses; others that are large, and not
equally surrounded by high brims, are  styled
fosse;  such as are long and narrow,furrows;
or if broad and superficial without brims, si-
nuosities.   Some are called digital impressions,
from their resemblance to the traces of a fin-
ger on soft bodies.
   We  shall abridge this article, which is ex-
ceedingly  diffuse  in the generality of anatomi-
cal books, and will endeavour  to  describe it
with all the clearness it will allow.
   The bones  composing the skeleton  are  so
constructed, that the end of every bone is per-
fectly 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, sy-
 narthrosis, and amphiarthrosis, or moveable,
immovable, and mixed  articulation.  Each of
the two first has its subdivisions.  Thus  the
 Diarthrosis, or moveable articulation, includes,
 1.  The enarthrosis,  as it is  called,  when a
 large  head  is admitted into  a deep cavity, as
 in  the articulation of the os femoris with the
 os innominatum.   2. Arthrodia, when a round
 head is articulated with a superficial cavity, as
 is the case of  the os humeri  and scapula.  3.
Ginglimus, or hinge-like articulation, as in the 
62
Osteology.
connection of  the thigh-bone with the tibia.
The enarthrosis and arthrodia allow of motion
to all sides ; the ginglimus only of flection and
extension.
   The  syfiarthrosis,  or immoveable articula-
tion,  includes,  1.  The  suture, 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 of the vertebrae, which are capable  of
motion in a certain degree, although they are
firmly connected together by intermediate car-
tilages.
   What is called symphysis is  the union  of
two bones  into one;  as in the lower jaw, for
instance, which in the  foetus consists of two
distinct  bones,  but becomes one in a more ad-
vanced  age, by the ossification of the uniting
cartilage.
   When bones are thus joined by the  means
of cartilages, the  union is styled synchondro-
sis ; when by ligaments, syneurosis.
   Cartilages  are  white,  solid,   smooth, and
elastic substances, between  the  hardness  of
bones and  ligaments, and  seemingly of a  fi-
brous texture.  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. 
Osteology.
63
  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 cavities of bones intended for mo-
tion,  as  in  the articulations, where  by  their
smoothness  they facilitate motions, which the
bones alone  could not execute with so much
freedom; or they serve to unite bones  toge-
ther,  as  in the symphysis pubis, or to length-
en them, as in the ribs.
  Many  of  them ossifying as we advance in
life, their number is less in the adult than in
the foetus, and of course there are fewer bones
in the old than in the young  subject.
  Of the second class of cartilages,  or  those
belonging to the soft parts, we have instances
in the larynx,  where we find them  useful in
the formation of the voice, and for the attach-
ment 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  ad-
heres very  firmly to their surface, and by its
smoothness  facilitates the  motion of muscles.
It likewise supports the vessels  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 im-
properly considered as  a distinct membrane, 
64
Osteology.
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 ossification of this membrane, at least
when it is in a sound state,  as  some late wri-
ters have supposed.
  The periosteum is  deficient  in  the teeth
above 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 a 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  difference  in colour and  consistence is
owing to accidental causes;  both kinds are of
the same nature, and may both  be described
under the common 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, 
Osteology.
65
which is likewise  supported in the cavities of
the bones by the long filaments of their reti-
cular 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 rami-
fy through all the vesicles of this  membrane.
  The bones,  and  the cells  containing the
marrow, are likewise furnished with lympha-
tics.   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 is
found in the bones of those  who die of  linger-
ing diseases.
  It is still a matter of controversy, Whether
the  marrow is sensible or not?   We are cer-
tainly not  able  to trace any nerves to it; and
from this circumstance, and its analogy to fat,
Haller has ventured to consider it as insensi-
ble.  On the  other hand, Duverney  asserts,
that an injury  done to this  substance in a liv-
ing animal was attended  with  great pain.  In
this dispute physiologists do not seem to have
sufficiently discriminated between the marrow
itself and the membranous 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 insensible parts, as much as
inspissated mucus or any other secreted mat-
ter  in the  body;  whereas the membrana me-
dullaris being vascular, though it possesses but
                      I 
66
Osteology.
 an obscure degree of feeling in a sound  state,
 is not perfectly insensible.
   The marrow was formerly  supposed to be
 intended  for  the  nourishment and  renewal of
 the bones; hut this doctrine is now pretty ge-
 nerally 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 purposes in the animal cecono-
 my;  but  their particular 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 pro-
 fessedly on the bones, describes the canals by
 which the  marrow is conveyed  through every
 part of their substance, and divides 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  similarity 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
passages do actually exist.
   The synovial glands are small bodies,* sup-
posed to be of a  glandular structure, and ex-
ceedingly vascular, secreting a fluid of a clear
mucilaginous nature, which serves to lubricate
the joints.   They are  placed in small cavities

  * It is now much doubted, however, whether the appear-
 ances in the joints, which are usually called glands, are any thing
more than assemblages of fat. 
Osteology.               67
in the articulations,  so as to be capable of be-
ing gently compressed by the  motion of the
joint, which  expresses their  juice in propor-
tion to the degree of friction.  When the sy-
novia is wanting,  or is of too thick a consist-
ence, the joint becomes stiff  and incapable of
flexion or extension.  This is what is termed
anchilosis.
   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 ei-
ther round or bursal.  The round ligaments
are white, tendinous, and inelastic.  They are
strong and flexible,  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 ligaments,  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 Burse mucosa, a few
were known to former anatomists, but by much
the greater number have been  since discover-
ed by Dr. Monro,* who observes,  that they
are to  be met with in the extremities  of the
body only; that many of them  are placed  en-
tirely on the inner  sides  of  the  tendons, be-
tween these  and the bones.  Many others co-
ver not only  the inner, but the  outer sides of
* See Descripion of the Burs* Mucosa, kc. 
68
Osteology.
the tendons, or are interposed between the ten-
dons  and external parts, as well as between
those and the bones.
   Some  are situated between the tendons and
external  parts only  or chiefly, some between
contiguous 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 ten-
dons  are  contiguous, and afterwards separate
from each other, we generally find a common
bursa divided into branches,  with which  it
communicates ; and a few bursae of contigu-
ous tendons communicate with each other.—
Some in  healthy children, communicate with
the cavities of the joints ; and in  many old
people he has seen such communications form-
ed by use or worn by friction, independent of
disease.
   Their proper membrane is thin and trans-
parent,  but very dense,  and capable of con-
fining air or any other fluid.  It is joined to the
neighbouring parts by the common cellular sub-
stance.   Between the bursa and the hard sub-
stance of bone, a thin layer  of  cartilage  or
of tough membrane is very generally interpos-
ed.   To the cellular substance on the outside
of the bursa, the  adipose substance  is con-
nected;  except where the  bursa covers a ten-
don,  cartilage, or bone, much exposed to pres-
sure or  friction.
   In  several  places a mass  of  fat,  covered
with the continuation of the membrane of the 
Osteology.
69
bursa, projects  into  its  cavity.  The edges
of this are divided into fringes.
  The inner side of the membrane is  smooth,
and  is extremely  slippery from the liquor se-
creted in it.
  The structure of the bursae bears a strong
resemblance  to  the capsular ligaments of the
joints.  1. The inner layer of the ligament,
like  that of the bursae, is thin and  dense.  2.
It is connected to the external ligaments by
the common  cellular substance.  3. Between
it and the bones,  layers of  cartilage, or the
articular cartilages, are interposed.  4. At the
sides of the joints, where it  is not subjected
to violent pressure and  friction,  the  adipose
substance is  connected with the cellular mem-
brane.   5. Within the cavities of  the joints
we   observe  masses of fat projecting,  covered
with similar blood-vessels,  and with similar
fimbriae 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 bursa behind the ligament which  ties
the  patella to the tibia.   7. The liquor which
lubricates the bursae has the same colour, con-
sistence, and properties 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 bursae constantly  communi-
cate  with the cavities of the joints, in others
they generally do so  ; from which we may in-
fer a sameness of  structure.
  When we examine the fimbriae common to
the   fatty  bodies of the joints and bursa?,  and 
70
Osteology.
   which have been supposed to be the ducts of
   glands  lodged within the masses of fat, we
   are not able to discover any glandular appear-
   ance within them.   And  although we observe
   many vessels dispersed upon the membranes
   of the fatty bodies and fimbriae ;  and that we
   cannot doubt that these fimbriae consist of ducts
   which contain a lubricating  liquor, and can
   even press such a liquor from them; yet  their
   cavities and orifices  are  so minute, that  they
   are  not  discoverable  even by the  assistance
   of magnifying-glasses.  These fimbriae appear,
   therefore,  to  be  ducts like those of the ure-
   thra, which  prepare a  mucilaginous  liquor,
   without  the assistance of any knotty or  glan-
   dular organ.
     Upon the  whole,  the synovia seems  to be
   furnished by invisible exhalent arteries by the
   ducts of the fimbriae,  and by  oil exuding from
   the adipose follicles by passages not yet disco-
   vered.
     The word skeleton, which by its  etymology
   implies simply a dry preparation,  is usually
   applied to  an assemblage of all the bones of
   an animal  united together in  their natural or-
   der.  It is said to be a natural skeleton, when
   the bones are connected together by their own
   proper  ligaments;  and an artificial one, when
   they are  joined  by  any  other substance, as
   wire, 8*c.
     The  skeleton  is  generally divided into the
:s  head, trunk,  and extremities.  The first divi-
"% sion includes the  bones of the cranium and
   face.  The bones  of the trunk are the spine,
   ribs, sternum, and bones of the pelvis. 
Osteology.
71
   The upper extremity on each side consists
of the two bones of the shoulder, viz. the sca-
pula and clavicle ; the  bone of the arm, or os
humeri;  the bones of the fore-arm,  and those
of the hand.
   The lower  extremity  on each side  of the
trunk consists of the thigh-bone 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.*   Its greatest diameter is from the
forehead to the occiput;  its upper part is call-
ed 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   tem-
ples ; its  posterior, or hind-part,  the occiput;
and its inferior part the basis.
   The bones of the head may be  divided into
those of the cranium and face.

  * The bones of the foetus  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 management of
children when very young. Vesalius, who has remarked the dif-
ference in people of different nations, observes, for instance, that
the head of a Turk is conical, from the early use of the turban ;
whilst that of an Englishman is flattened by the chin-stay. Some
of the  latest  physiologists suppose, with good reason, that this
difference is chiefly owing  to certain natural causes with which
we are as yet unacquainted. 
7 2               Osteology.
      1. ito;z£'s of the Cranium and Face*

   There are eight bones of the cranium, viz.
the coronal bone, or os frontis; the two pari-
etal  bones, or ossa bregmatis;  the  os  occipi-
tis;  the two temporal  bones;   the sphenoid
bone; and the os ethmoides, or  cribriforme.
   Of these,  only  the os occipitis and  ossa
bregmatis are considered as proper to the cra-
nium ; the rest being common both to the cra-
nium 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 spon-
gy substance called diplb'e.
   In this,  as  in all the 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 convex, its concave side  being turned to-
wards  the brain.  This  bone,  in the  places
where it is united to the temporal bones, is
very thin,  and has  there no diploe.  It  is like-
wise 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 instrument,   is sometimes
productive of immediate death. In these cases,
the  sword  passing  through the  weak part of
the bone,  penetrates  the brain,  and divides
the nerves at their origin;  or perhaps opens 
Osteology.
73
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
easily 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
supporting the upper end of the bones of the
nose.  The four others  are  called angular or
orbitar  processes.   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 angu-
lar  processes.   Between these a ridge is ex-
tended in form of an  arch, and on this the eye-
brows are placed.  It is called the orbitar or
superciliary ridge, and in some measure covers
and defends the globe of the eye.  There is a
hole in this for the passage of the frontal ves-
sels  and nerves.   This  arch is  interrupted
near the nose by a small pit, in which the ten-
don  of the  musculus obliquus  major  of the
eye is fixed.  From the under part of each su-
perciliary ridge a thin plate runs a considera-
ble way backwards, and has  the name of  orbi-
tar ; 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 the bone, which is fill-
ed up by the cribriform part  of the os ethmoi-
des.
                     K 
74               Osteology.

  On examining the inner surface of this bone
at its  under and  middle part,  we observe an
elevation  in form of a ridge, which has been
called the spinous process ; it ascends for some
way, dividing the bone into two considerable
fossae,  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  continued to the upper and
back part of the bone.  It has the falx fixed to
it, and part of the longitudinal  sinus lodged in
it.  Besides  the  two fossae, there are many
depressions, which appear like  digital impres-
sions,  and owe their formation to the promi-
nent circumvolutions of the brain.
  In the foetus, the forehead is composed  of
two distinct bones ;  so that in them the sagit-
tal  suture reaches from the os occipitis to the
nose.  This bone is almost every where com-
posed of two tables  and a  diploe. These two
tables  separating from  each other under the
eyes, form two cavities, 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 mu-
cus is secreted,  which is  constantly  passing
through two small holes into the nostrils, which
it serves to moisten.
  The os frontis is joined by  suture to  many
of the bones of the  head, viz.  to the parietal,
maxillary, and temporal bones ; to the os eth-
moides;  os sphenoides; os unguis ; and ossa 
Osteology.
75
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 circumfer-
ence, except at its lower part.   It will be ea-
sily conceived,  that  these  bones which  com-
pose the superior and lateral parts of the cra-
nium,  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 du-
ra mater;  and at their upper edge the  groove
for the superior longitudinal sinus.
   The ossa parietalia are joined to each other
by the sagittal  suture ;  to the os sphenoides
and ossa temporum  by the squamous suture ;
to the os  occipitis by the lambdoidal suture,*
so called from  its resemblance to the  Greek
letter lambda ;  and to the os frontis by the co-
ronal suture.
   In  the foetus, the  parietal bones are sepa-
rated from the middle of the divided os frontis
by a portion of the  cranium then unossified.
   The  occipital bone forms the posterior and
inferior  parts of the  skull; it approaches near-
ly to  the shape of a lozenge, and is indented
throughout three  parts  of its circumference.

  * The lambdoidal suture is sometimes very irregular, being
composed of many small sutures, which surround so many lit-
tle bones called ossa triquetra, though perhaps improperly, as
they are not always triangular. 
76
Osteology.
  There is a considerable hole in the inferior
portion of this bone,  called the foramen mag-
num,  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 si-
nuses ;  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 foramen magnum, are
two processes, called the condyles,  one on
each side; they are of an oval figure, 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 attach-
ment  to several 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 fossae
are formed  by the cross, two above  and two
below.  In the former are  placed  the posterior
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 
Osteology.
77
this bone^; it serves for the reception of the
medulla oblongata.
   The os occipitis is of greater strength and
thickness, than  either of the other bones of
the  head, though irregularly  so;  at its inferi-
or  part, where it is thinnest, it is covered by
a great number of muscles.
   This bone, from its  situation, being more
liable  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 exposed to danger.
   It is joined to  the parietal  bones by  the
lambdoidal suture, and to the ossa temporum,
by the additamentum of the temporal suture.
It is likewise connected  to the  os sphenoides
by the cuneiform process.  It is by means of
the os occipitis that the head is united to the
trunk,  the two  condyles  of this  bone  being
connected to  the superior 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 hard-
ness.  This last  is shaped like a pyramid.
   Each  of these divisions affords processes
and cavities: externally  there are three pro-
cesses ;  one   anterior,  called the  zygomatic
process ;  one  posterior,  called the mastoid or
mamillary process, from its resemblance to a
nipple ; and one  inferior, called  the styloid pro-
cess, because it is shaped like a stiletto, or dag-
ger. 
78
Osteology.
   The cavities are,  1. The meatus auditorius
externus.  2.  A  large fossa which serves for
the articulation of the lower jaw ; it is before
the meatus auditorius, and immediately under
the zygomatic process.  3. The  stylo-mastoid
hole,  so  called from its situation between the
styloid and mastoid processes; it is likewise
styled the aquaeduct 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 begin-
ning of the internal jugular vein is lodged. An-
terior 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 ter-
minates at the end of the os petrosum.—At this
part of each temppral 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 fos-
sae ; one  superior and anterior ;  the  other in-
ferior and posterior: the  latter  of these com-
poses part of  the fossa, in which the  cerebel-
lum 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  ob-
serve the  meatus  auditorius internus,  into
which enters  the double nerve of the  seventh
pair.  On the under side of this process, part
of a hole appears,  which  is  common to  the 
Osteology.
79
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 treat-
ing of the organs of hearing.
  The ossa temporum are joined to the ossa
malarum, 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.
  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 nari-
um.  The upper  part of each  wing forms a
share  of the  temple.  The  fore  part of this
belongs  to  the orbit; 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  remarka-
ble  processes  are the ptergoid or aliform, one
on each side of the body  of the bone, and at
no great distance from it.   Each of these pro-
cesses is divided into two wings,  and of these
the  exterior one is the widest.  The other ter-
minates in a hook-like process. 
80
Osteology.
  The  internal surface of this bone affords
three fossae.  Two of these are formed by the
wings of the  bone,  and  make  a part of the
lesser fossae 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 anteriorly process-
es called the clinoid processes.
  There are twelve  holes in this bone, viz. six
on  each side.  The first  is the  passage of th|
optic 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  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 mem-
brane ;  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 max-
illaria,  ossa malarum, ossa  palati,  and vo-
mer. 
Osteology.
81
  This bone  makes  part of the basis of the
skull, assists in forming the orbits, and affords
attachment to  several muscles.
  The  os ethmoides  is situated at  the fore
part of the  basis of the cranium, and is of a
very irregular figure.  From the great number
of holes with which  it is pierced, it is  some-
times called os  cribriforme or  sieve-like bone.
  It 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  ol-
factory nerve.  From  the middle 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 cris-
ta  galli,  from  its supposed resemblance  to
a cock's comb.  To  this  process  the falx  of
the dura  mater is attached.  The exterior pro-
cess, which has the same common basis as the
crista 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 inclined to one side.
   The lateral parts of this bone are compos-
ed  of a cellular substance ; and these cells are
so  very 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. 
82
Osteology,
  The different cells  of this bone, which are
numerous, and which are  every where  lined
with the pituitary membrane, evidently  serve
to enlarge 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 themselves 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 serosi-
ty  which they  supposed  was  discharged
through it in a common cold.—All  the  holes
of 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.  Mat-
ter is  indeed sometimes discharged 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  discharge
themselves externally. 
Osteology.
83
   Before we leave the bones of the head, we
wish to make some general observations on its
structure and figure.—As the  cranium  might
have been composed of  a single bone,  the ar-
ticulation of its several  bones being absolute-
ly without  motion,  it may be asked perhaps,
Why  such a multiplicity of  bones,  and  so
great  number of  sutures? Many  advantages
may possibly arise from  this plurality of bones
and sutures,  which may not yet have been
observed.   We are able, however, to point
out many useful ends, which could only be ac-
complished by this peculiarity of  structure.—
In this, as in all the other works of nature, the
great wisdom of the Creator is evinced, and can-
not fail to excite our admiration and gratitude.
   The cranium, by being divided into sever-
al bones, grows much faster and with greater
facility,  than if it was composed of one piece
only.  In  the  foetus, the  bones,  as we have
before observed,  are  perfectly distinct from
each other.  The  ossification begins  in  the
middle of each bone, and proceeds gradually
to the  circumference.  Hence the ossification,
and of course the increase of the head, is car-
ried on  from  an infinite  number  of points at
the same time, and the bones consequently ap-
proach each other in the  same proportion.  To
illustrate this doctrine more clearly, if it can
want further illustration, suppose it necessa-
ry for  the parietal  bones which compose  the
upper  part of the  head,  to extend their ossifi-
cation, and form  the  fore  part of the head
likewise.—Is it not  evident,  that this  process 
84
Osteology.
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 foetus,  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 ma-
ter, are evidently  of great utility in  prevent-
ing 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 be-
comes  fractured.   The fissure,  which  in  a
head composed of only one  bone, would  be
liable to extend itself through the whole of it,
is checked, and sometimes perhaps 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  ef-
fect,  and in young subjects  their utility in
this respest must be still more obvious.
   The  spherical shape  of the  head seems like-
wise to  render it more capable  of resisting ex-
ternal violence than any other  shape would do.
In a  vault, the  parts mutually  support and
strengthen each other, and this happens in the
cranium. 
Osteology.
85
        2.  Proper Bones of the  Face.

  The face, which consists of a great number
of bones, is commonly divided into the upper
and  lower jaws.  The upper jaw consists of
thirteen  bones, exclusive of the teeth.   Of
these,  six are placed on each side of the max-
illa superior, and  one  in  the  middle.
  The bones, which are in pairs, are the os-
sa malarum, ossa maxillaria, ossa nasi,  ossa
unguis, ossa palati, and ossa spongiosa inferi-
ora.   The single bone is the vomer.
  These 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 ex-
terior and a little convex ; a second superior
and  concave,  forming the inferior part and
sides of the orbit; and a  third posterior,  irre-
gular,  and hollowed for  the lodgment  of the
lower part of the temporal muscle,
  The angles of each bone form four process-
es, two of which may be called orbitar process-
es ; of these the upper one is joined by suture
to the os frontis, and  that below to the maxil-
lary  bone.   The third is connected with  the
os sphenoides by means of the transverse su-
ture  ; and the fourth is joined to the  zygoma-
tic process of the  temporal  bone, with  which
it forms the zygoma.
  These bones, which are of a  very irregular,
figure, are so  called  because  they  form  the
most considerable portion of the upper jaw. 
86
Osteology.
 They  are  two in number,  and generally re-
 main distinct through life.
    Of  the  many processes which are  to be
 seen on  these bones, and which  are connect-
 ed  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. An-
 other forms a kind of circular sweep at the in-
 ferior part of the bone,  in which are the alve-
 oli  or  sockets for the teeth:  this is called the
 alveolar process.   A third process  is united to
 the os  malae on  each side.  Between this and
 the nasal process there  is a thin plate, which
 forms a  share of the orbit,  and  lies  over a
 passage for the superior maxillary  vessels and
 nerves.—The  alveolar process has posterior-
 ly  a considerable  tuberosity on  its  internal
 surface, called the maxillary  tuberosity.
   Behind the alveolar process we  observe two
 horizontal  lamellae,  which  uniting  together,
 form a part of the roof  of the mouth,  and di-
 vide it from the nose.  The hollowness of the
 roof of the mouth is owing to this partition's
 being seated somewhat higher than the alveo-
 lar process.—At the fore part of the horizon-
 tal  lamellae there  is a hole called foramen inci-
 sivum,  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
l^asal process, which with the os unguis  and 
Osteology,
87
os spongiosum inferius, forms a passage for
the lachrymal duct.
  Where these two bones are united to each
other,  they  project somewhat upwards  and
forwards, leaving between them a furrow, in-
to which the lower portion of the septum na-
si is admitted^
  Each of these bones  being hollow, a consi-
derable sinufc is formed under its orbitar part.
This cavity,  which is  usually  named after
Highmore, though it was described by Fallopi-
us  and others before  his time, is lined with
the  pituitary membrane.  It is  intended for
the same purposes as 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.  Externally they are somewhat  convex,
and internally 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 superiora, posteriorly  and in-
teriorly to the septum  narium, and  below to
the  cartilages, that compose the rest  of the
nostrils.
   These  little transparent bones  owe their
name to their supposed resemblance to a fin-
ger-nail.  Sometimes they are called ossa la-
chrymalia,  from their concurring with the na- 
88
Osteology.
sal 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 of these bones is connected  with the
os frontis, os ethmoides, and os maxillare su-
perius.
   These bones which are situated 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 internal surface.   This spine  appears to
be a continuation of that of the superior  max-
illary bones,   and  helps to  form the septum
narium.
   These bones are joined to  the ossa maxilla-
ria superiora, os  ethmoides,  os  sphenoides,
and  vomer.
   This bone derives its name from its resem-
blance  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 be- 
                  Osteology.  #             89

coming narrower and shallower, receives some
part of the nasal lamella ethmoidea; the rest
serves to  support  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 vomer  is united to the os sphenoides,
os ethmoides,  ossa maxillaria superiora, and
ossa palati.   It forms part of the septum nari-
um,  by dividing the back part of the nose into
two nostrils.
   The parts which are usually described by
this name, do not seem to deserve  to be dis-
tinguished 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  lamellae 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, covering
the opening  of the lachrymal duct  into the
nose.
   These  bones are covered with the pituitary
membrane ; and, besides their connection with
the ethmoid  bone, are joined to the ossa max-
illaria superiora,  ossa palati, and ossa unguis.
   The maxilla inferior, or  lower jaw,  which
in its shape resembles  a horse-shoe, consists
of two distinct  bones in the foetus; but these
unite together  soon after birth, so as to form
                     M 
90
Osteology,
only one bone.   The upper edge of this bone,
like the os maxillare superius, has an alveolar
process,  furnished with sockets  for the teeth.
  On each side  the posterior part of the bone
rises almost perpendicularly into two process-
es.  The  highest of these, called  the coronoid
process,  is pointed .-and thin, and  serves for
the insertion of the temporal muscle.   The
other,  or condyloid process,  as it is called, is
shorter and thicker, and ends  in  an oblong
rounded head, which is received into a fossa
of the temporal bone,  and is  formed for a
moveable articulation with the cranium. This
joint is  furnished with  a moveable cartilage.
At the bottom of each  coronoid process, on
its  inner part, we observe a foramen extend-
ing under the roots of all the teeth, and ter-
minating at the  outer surface  of the bone  near
the chin.  Each of these canals transmits an
artery, 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
cavity 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 condyles  alternately backwards  and
forwards from the cavity to the eminence, and
vice versa, as in grinding the  teeth.  The car-
tilages,  by adapting themselves to the differ-
ent inequalities  in these several motions of the 
Osteology.
91
jaw, serve to secure the articulation, and  to
prevent any injuries from friction.
  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 struc-
ture, formed for  the purposes of mastication
and the  articulation of the voice.   It will be
necessary to consider their composition and fi-
gure,  their number 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
appears  above  the gums.  The root is fixed
into the socket,  and the  neck is  the  middle
part between the  two.
  The teeth  are composed of two substances,
viz. enamel and  bone.  The  enamel,  or  the
vitreous  or  cortical part of the tooth,  is  a
white and very hard and compact substance
peculiar  to the teeth, and appears fibrous o*r 
92               Osteology.
striated when broken. This substance is thick*
est on the grinding surface, and becoming gra-
dually thinner,  terminates insensibly at the
neck of the tooth.   Ruysch * affirmed, that he
could  trace the arteries into the hardest part
of the teeth; Liewenhoeckf suspected the fibres
of the  enamel to  be so  many vessels;  and
Monro % says,  he  has frequently injected 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 be-
ing 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 pe-
netrate 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 invested by a perios-
teum,  and  that the swellings 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 substance,

  * Thefadr 10. no. 27.
  f Arcan. Natur continuat. Epiftbl.
  % Anat. of the Human Bone's.
  § Hunter on the Teeth. 
Osteology.
93
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 becom-
ing 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 sock-
ets, where  we find it  adhering to the gums.
This membrane, 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 sensibility.   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.*  The  incisores are  the four
teeth  in the  fore  part  of  each jaw.   They
have each  of them two  surfaces ; one anterior

   * Mr. Hunter has thought proper to vary this division. He
retains the old name of incisores  to the four  fore teeth, but he
distinguishes the canine teeth by  the name of the cuspidati. The
two teeth ••which are next to these,  and which have been usu-
ally ranked with the molares, he calls  the bicuspides; and he
gives the name ofgrinders only to the three last teeth on each
side. 
94
Osteology.
 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 being 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.*
   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 furnished 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 se-
 parated into two points, and each of these points
 has  sometimes been  described as  a distinct
 fang.

  * Mr. Hunter remarks of these teeth,  that we may trace in
 them a similiarity in shape, situation, and use, from the most
 imperfectly carnivorous animal, which we believe  to be the hu-
man species, to the lion, which is the most perfectly carnivo-
rous. 
Osteology.
95
   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 pro-
priety 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  cutting  the  gum till after the age of
twenty, and  sometimes  not  till  much later in
life,   is called dens sapientie.
   There  is in  the structure and arrangement
of all these teeth an art which cannot be suf-
ficiently 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  muscles,  but  in elevation
chiefly from the temporalis and masseter; and
that  the aliment constitutes  the object of re-
sistance.  It will appear, then, that the  mola-
res,  by being placed nearest  the  centre of mo-
tion,  are calculated to press with a  much
greater force than the other teeth, independent
of their grinding powers which  they  possess
by 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. 
96               Osteology.
   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 denti-
tion,  however, in  consequence  of irritation
from the  teeth,  frequently take place in the
fourth or fifth month.—About the twentieth
or twenty-fourth  month,  the canini and two
molares make their appearance.
   The  dangerous  symptoms that  sometimes
accompany dentition,  are owing to the  pres-
sure  of the teeth on the gum,  which they ir-
ritate so  as to excite pain and inflammation.
This irritation 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  num-
ber of teeth which  may chance to seek a pas-
sage at the same  time.   Were they all to ap-
pear  at once, children  would  fall  victims to
the  pain  and excessive irritation;  but Nature
has  so  very wisely disposed  them, that they
usually appear one  after the  other,  with  some
distance of time between each.  The first in-
cisor 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. 
Osteology.
97
  These  20 teeth,  viz. eight incisores, four
canini, and eight molares, are called tempora-
ry or milk teeth, because they are all shed be-
tween 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 dis-
appear, as the under ones increase in size, till
at length  the temporary,  or upper teeth, hav-
ing no longer any support, consequently fall
out.
  To these 20 teeth, which succeed the tem-
porary 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 the face is rounder and flatter
in children than in adults.
  With regard to the formation of the teeth,
we may observe, that in a foetus of four months,
the alveolar process appears only as a shallow
longitudinal groove,  divided by minute ridges
into  a number of intermediate depressions ; in
each of which we find a small  pulpy substance
surrounded by a vascular  membrane.   This
pulp 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 incrusted with the enamel.   How
                     N 
98
Osteology.
the latter is formed and  deposited, we are not
yet able to determine.
   The rudiments of some of the  adult teeth
begin to be formed at a very early  period, for
the  pulp of one of the incisores may general-
ly be  perceived  in a foetus 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 sapientie,  usually  between
the 20th and 30th year.
   The teeth, like other bones, are liable to be
affected by  disease.   Their removal is like-
wise the natural consequences of old  age; for
as we  advance  in life,  the alveoli fill up,
and the teeth, especially the incisores, fall out.
When this happens, the chin projects forward,
and the face is much shortened.


            4. Of the Os Hyoides.*


   The os hyoides, which is placed at the root
of the tongue,  was so called by the ancients
on  account of its  supposed resemblance  to
the Greek letter  v.

   * This bone is very seldom preserved with the skeleton, and
cannot be included among the bones of the head, or any other
division of the skeleton  Thomas Bartholin has perhaps very
properly described it among parts contained in the mouth ; but
the generality of anatomical writers have placed it, as it is here,
after the bones of the face. 
Osteology.
99
  It will be  necessary to distinguish in it, its
body, horns, and appendices.
  The  body, which  is the middle and broad-
est  part of the bone,  is so placed that it may
be  easily  felt at the  fore  part of the throat.
Anteriorly it is irregularly convex,  and its in-
ner surface is unequally concave.  Its cornua,
or horns,  which  are  flat and a little bent,  be-
ing much  longer than the body part, may be
described  as  forming the sides of the «. The
appendices, or little horns, as they  are called
by M.  Windslow, and some other writers,  are
two processes which rise  up from the articu-
lations of  the cornua with the body, and are
usually connected with the  styloid process  on
each side by  means of a ligament.
  The  uses  of  this bone  are to support the
tongue, and afford attachment to a great num-
ber of  muscles;  some of  which  perform the
motions of the  tongue,  while others act  on
the larynx and fauces.


    Sect.   III.  Of the Bo7ies 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  vertebra, forming a long  bo-
ny column, in figure  not much unlike the  let-
ter/.   This  column,  which extends from  the 
100
Osteology.
head  to  the  lower part of the body, may be
said to consist of two irregular  and unequal
pyramids, united 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 py-
ramid are  called true vertebra,  in  contradis-
tinction to those of  the lowermost pyramid,
which,  from  their being immoveable  in the
adult, are s\y\e& f dse vertebra.   It is upon
the bones  of the spine that the body turns ;
and it is  to  this circumstance they owe  their
name, which  is  derived from  the  Latin verb
vertere, to turn jMmsk. 2Mc«li«?ill C«ll«~tv
   The  true  vertebrae are divided  into three
classes  of cervical, dorsal  and lumbar verte-
brae.—The false vertebrae consist of the os sa-
crum and os coccygis.
   In  each vertebra, as in other bones, it will
be necessary to remark the  body of the bone,
its processes,  and cavities.
   The  body,  which  is  convex before,   and
concave  behind, where it  assists  in  forming
the cavity 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 process.  On  each side of this are two
others, which,  from their  situation with re-
spect to  the spine, are called  transverse pro-
cesses.   The four others are styled oblique or
articular processes.  They  are  much smaller
than  the spinous or transverse ones.  Two of 
Osteology.
101
them are placed on the  upper, and two on the
lower part of each vertebra, rising from near
the basis  of each transverse process.  They
have gotten the name of oblique processes, 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 infe-
rior 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.
   In each vertebra, between its body and  its
processes, we find a hole  large enough to ad-
mit a finger.  These holes or foramina, corre-
spond 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 ver-
tebra. Each of these notches meeting with a
similar opening  in the vertebra above or be-
low  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 toge-
 ther by means of a  substance, which in young
 subjects  appears to be of a ligamentous,  but
 in adults  more of a cartilaginous nature. This
 intervertebral substance,  which forms a kind 
102
Osteology.
of partition between the  several vertebrae, is
thicker  and more flexible between the lumbar
vertebrae than in the other parts of the spine, the
most considerable motions of  the trunk being
performed  on those vertebrae.  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 elasticity seems to be the
reason why people who  have been long stand-
ing,  or have carried a considerable  weight,
are found to be shorter than when they  have
been long in bed.   In the two first  instances
the intervertebral cartilages  (as  they are usu-
ally  called)  are  evidently  more exposed  to
compression  than when we are  in bed in an
horizontal  posture.
  In  advanced  life these cartilages  become
shrivelled,  and of course lose much of their
elasticity.  This may serve to account for the
decrease in stature and the stooping forward
which are  usually to  be observed in old peo-
ple.
  Besides  the connection of the several verte-
brae by means of this intervertebral substance,
there  are likewise many strong ligaments, both
external  and internal, which  unite  the bones
of the spine to each other.   Their union is al-
so strengthened by a variety of strong muscles
that cover  and surround the spine.
  The bones of the spine are found to dimi-
nish in  density, and to  be less  firm  in  their
texture in proportion as  they increase in bujk;
so that  the lowermost vertebrae, though the 
Osteology.
103
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 flexi-
bility and suppleness,  seems to require  light-
ness as one of its essential properties.
   In  very young children, each vertebra con-
sists of three bony pieces united by cartilages
which afterwards ossify.
   There  are  seven vertebrae  of  the neck—
they  are of a firmer  texture  than the  other
bones of the  spine. Their transverse process-
es  are forked  for  the  lodgment of muscles,
and at the  bottom of  each we observe a fora-
men,  through which  pass the cervical artery
and vein.   The first and second of these ver-
tebrae  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  occipital
bone with which it is articulated.  This verte-
bra, 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 articu-
lated  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 occipital bone.  By this connection  the
head  is allowed to move forwards and back-
wards, but has very little motion in any other
direction. 
104
Osteology.
   The second vertebra has gotten the name of
dentata,  from its having, at its upper and an-
terior  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  pro-
cess is of a cylindrical shape,  somewhat  flat-
tened, however, anteriorly and posteriorly.  At
its fore-part where it is  received by the atlas,
we may observe  a  smooth, convex, articulat-
ing surface.  It is  by means  of this articula-
tion that the head performs its  rotatory motion,
the  atlas in that case moving  upon this odon-
toid process as upon a pivot.   But when this
motion  is in  any considerable degree, or,  in
other words, when  the head moves much ei-
ther to the right or left,  all the cervical verte-
brae seem to assist,  otherwise the spinal  mar-
row would be in danger of being divided trans-
versely by the first vertebra.
   The  spinous  process of each of the cervi-
cal vertebrae is shorter, and their articular pro-
cesses more  oblique,  than in the other  bones
of the spine.
   These 12 vertebrae 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 body of each vertebrae;  which uniting with
similar depressions  in the vertebrae 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 
Osteology.
105
(excepting the two last) we find an articulating
surface for receiving the tuberosity of the ribs.
  These five vertebrae  differ only from those
of the back in their being larger,  and in hav-
ing their spinous  processes  at a  greater dis-
tance from  each other.   The most  consider-
able motions of the  trunk are made on these
vertebras; and these motions could not be  per-
formed with so much ease, were the process-
es placed nearer to each other.
  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 infe-
rior portion being bent  a little forwards.   Its
superior part has two oblique processes which
are articulated with the  last of the lumbar ver-
tebrae ; and  it  has  likewise  commonly three
small spinous processes, which gradually be-
come  shorter, so that the lowermost is not so
long as the second, nor the second as the up-
permost.   Its transverse processes are formed
into  one oblong process, which becomes  gra-
dually smaller as it descends.  Its concave or
anterior side is usually  smooth, but its poste-
rior  convex side  has many prominences  (the
most remarkable of which are the  spinous pro-
cesses just  now mentioned,) which are filled
up and covered with the muscular  and tendi-
nous 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
                     O 
106
Osteology.
 lodged in a triangular  cavity, that becomes
 smaller  as it descends, and  at length termi-
 nates obliquely 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, being secured at its back part only
 by a very strong membrane, so that a  wound
 at this part must be extremely dangerous.
   The os sacrum is united laterally to the os-
 sa innominata or hip-bones, and below to the
 coccyx.
   The coccyx, which, like the os sacrum, is
 in young people made up  of three or four dis-
 tinct 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 en-
 abled to sit with ease.
   This bone is nearly of a triangular shape,
, being broadest  at  its  upper  part, and  from
 thence growing narrower to its apex,'where it
 is not bigger than  the little finger.
   It has got its name from  its  supposed re-
 semblance  to  a cuckow's beak.    It differs
 greatly from the vertebrae, being commonly
 without any processes, and having no cavity
 for  the  spinal  marrow,  or foramina for the
 transmission of nerves.
   The spine,  of which we have now  finished
 the  anatomical  description, is destined for ma-
 ny  great and  important  uses.  The  medulla
 spinalis is lodged in its bony canal secure from 
Osteology.
107
external injury.   It serves as a defence to the
abdominal and thoracic viscera,  and at the
same time supports the  head,  and gives a ge-
neral firmness to  the whole trunk.
   We have before compared it to the letter^
and its different turns will be found to render
it  not very unlike the figure of that letter.—
In the neck we see it projecting somewhat for-
ward 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. Af-
ter this, in the loins, it again projects forwards
in a  direction with the centre of gravity, by
which means we are easily 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 forming the pel-
vis,  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
easily fractured than it is now: and by confin-
ing the trunk to  a  stiff situation,  a variety of
motions would have been  altogether prevent-
ed, which are now performed with ease by the
great number of bones of which it is compos-
ed.
   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 be- 
108              Osteology.
comes stiff with the  assistance of its muscles,
and  accommodates itself to the load, as if it
was  composed only of one bone— In stooping
likewise, or in turning to either side, the spine
turns itself in  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 a number of bones,
and  intended  for  such  a variety of  motion,
there must be a greater  danger of dislocation
than  fracture  ; but we shall find, that  this is
very wisely guarded against in every direction
by  the processes  belonging to each vertebra,
and by the ligaments, cartilages, he. by which
these bones are connected with each other.


       2. Of  the Bones of the Thorax.


  The thorax,  or chest, is  composed of ma-
ny bones, viz. the sternum which is placed at
its  anterior part,  twelve ribs  on  each  side
which make up its lateral parts, and the dor-
sal vertebrae which constitute its posterior part.
These last have been already described.
  The sternum is the long bone  which  ex-
tends  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 ster-
num in the adult  state is found to consist on- 
Osteology.
109
ly of three pieces, and sometimes becomes one
bone.   It is however generally described  as
being composed of three parts—one superior,
which is broad, 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 cartilage, 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  articulated to the sternum are call-
ed  true ribs, and the five lower ones that are
not immediately attached to that bone are call-
ed false ribs.
   On the inferior and interior  surface of each
rib, we  observe  a sinuosity for the lodgment
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 vertebrae and
sternum.   Every rib (or at least  the greater
number of  them) has at its posterior part two
processes ;  one at its extremity called the head
of the rib,  by  means of which it is articulated 
110
Osteology.
with the body of two vertebrae;  and another,
called its tuberosity, by which it is articulated
with  the transverse process of the lowest of
these two vertebrae.   The first rib is not arti-
culated by its extremity to two vertebrae, be-
ing simply  attached  to the upper part of the
first vertebra of the back.   The seven superi-
or or true ribs are articulated anteriorly with
the sternum by  their cartilages ;  but the false
ribs are supported in  a  different  manner—the
eighth,  which is the first of these ribs,  being
attached by  its cartilage 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 ver-
tebra, and not with a transverse process ; and
anteriorly,  their cartilage is loose, not  being
attached to  the cartilages  of the other ribs;
and this seems to  be, because the most  consi-
derable motions of the  trunk are  not perform-
ed on the lumbar vertebrae  alone, but likewise
on the two last vertebrae 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  vertebrae,
and with the transverse processes, the  moti-
on of the two last vertebrae, and consequently
of the whole trunk, would have been impeded.
  The ribs help to form the cavity of the tho-
rax ; they afford attachment to different mus-
cles ;  they are useful in respiration; and they
serve  as a security to the heart and lungs. 
Osteology.
ill
       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 pro-
perly belong.
  In children, each os innominatum is com-
posed of three distinct bones; but as we ad-
vance in  life the intermediate cartilages gradu-
ally ossify, and  the  marks of the original se-
paration  disappear, so that they become  one
irregular bone ;  still however continuing to re-
tain  the  names of ilium,  ischium, and pubis,
by which their  divisions were  originally dis-
tinguished, and to  be  described as  three dif-
ferent  bones by  the generality of anatomists.
The os ilium forms the upper and most consi-
derable  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 cartila-
ginous substance, and is united to the os pu-
bis before 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 commonly known by the name of the
haunch.   This  crista  rises up  like an arch;
being turned somewhat outwards, so as to re-
semble the wings of a phaeton.
   Externally this bone is unequally prominent
and  hollowed for the lodgment of muscles; in-
ternally  we  find it  smooth and concave.  At 
112
Osteology.
its lower part there is a considerable  ridge on
its  inner  surface.  This  ridge  extends from
the os sacrum,  and corresponds with  a similar
prominence both on that  bone and the  ischi-
um ; forms with the inner part of the ossa pu-
bis what in midwifery 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 process-
es.   From the anterior  spinous process, the
sartorius  and tensor vaginae femoris muscles
have  their  origin;  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 low-
er part from the os sacrum to the sharp-point-
ed process of the ischium.  This hole affords
a passage to the great sciatic nerve, and to the
posterior  crural  vessels under  the pyriform
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 consider-
able portion of the acetabulum, and  sends a
sharp-pointed process backwards,  called the
spine  of the ischium.  To this process the  li- 
Osteology.
113
gament 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 supports us
when we  sit, is large and irregular,  affording
origin to several muscles.  From this tubero-
sity  we find the bone becoming thinner and
narrower.  This part, which has the name of
ramus  or branch,  passes  forwards  and up-
wards, and concurs with the ramus of the os
pubis,  to form  a large hole called the foramen
magnum ischii, or thyroideum, as it  is some-
times 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  attachment 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
cartilage, which forms what is called the sym-
physis pubis.
   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  sym-
                     P 
114
Osteology.
 physis, and the ramus  is a thin process which
 unites with the ramus of the ischium, to form
 the foramen thyroideum.
   The three bones we have described as com-
 posing each os innominatum, all assist in form-
 ing the acetabulum, in  which the head of the
 os femoris is received.
   This  cavity is every where  lined  with a
 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 improper-
 ly 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  lodged 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 midwifery.
   It is worthy of observation, that in  women
 the os sacrum is usually shorter, broader, and
 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
upper extremity and the lower. 
Osteology.              115
       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
clavicula and the scapula.
  The former,  which is so named from its re-
semblance to the key in use amongst the an-
cients, is a little curved at both its extremities
like an italic f.   It is likewise called jugulum,
or collar-bone,  from its situation.  It is about
the size of the little finger, but longer, and be-
ing 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  extremi-
ties.  The body is rather flattened than round-
ed.   The anterior  extremity is formed  into
a slightly convex head, which is nearly of a tri-
angular shape.   The  inferior  surface of the
head  is articulated  with the sternum.  The
posterior extremity, which is flatter and broad-
er than the  other, is connected to a  process
of the scapula, called  acromion.   Both 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 
116
Osteology.
brought too much forwards, or carried too far
backwards.   It affords  origin to several mus-
cles, and helps to cover and protect the sub-
clavian vessels, which derive their name from
their situation under this bone.
  The  scapula,  or  shoulder-blade, which is
nearly 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 un-
equal thickness,  and, like  all other broad, flat
bones, is somewhat cellular.  Exteriorly it is
convex, and interiorly  concave, to  accommo-
date itself to the convexity of the ribs.   We
observe in this bone three unequal sides, which
are thicker  and stronger than the body  of the
bone, and are therefore  termed its costa.  The
largest  of the three, called also the basis, is
turned towards the vertebrae.  Another, 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.   Externally the
bone  is  elevated into  a considerable  spine,
which rising small at the basis of the scapula,
becomes gradually higher  and broader,  and
divides  the outer  surface of the bone into  two
fossae.  The superior of these, which is  the
smallest,  serves  to lodge  the  supra spinatus
muscle ; and the  inferior 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 
Osteology.
117
infra  spinati muscles.   The scapula has like-
wise 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 up-
wards.  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 ful-
crum ; 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 de-
fence to the trunk.

            2. Bones of the Arm.

  The arm is commonly divided into two parts,
which are articulated to each other at the el-
bow.  The upper part retains the name of arm,
properly so called, and the  lower part is usu-
ally called the fore-arm.
  The arm is composed of  a single bone call-
ed os humeri.  This bone,  which is almost of
a cylindrical shape, may be divided into its bo-
dy 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 mus- 
118
Osteology.
cle of the arm ; and on each side of the groove,
at the upper end of the bone, there is a tuber-
cle to which the spinata muscles are fixed.
   The  lower extremity has several processes
and cavities.   The principal processes  are its
two condyles, one exterior and the  other inte-
rior, and of these the last is the largest.  Be-
tween these two we observe two lateral  protu-
berances, which, together with a middle cavi-
ty, form as it were a kind of pully upon which
the motions of the fore-arm are chiefly per-
formed.  At each side of the condyles, as well
exteriorly as interiorly, there is  another emi-
nence which gives origin to several muscles of
the hand and fingers.  Posteriorly and superi-
orly, speaking with respect to the  condyles, we
observe a deep fossa which receives  a  consi-
derable process of the ulna ; and anteriorly and
opposite to  this fossa,  we observe  another,
which is much less and  receives another pro-
cess of the same bone.
   The  body of the  bone has at its upper 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  capsu-
lar ligament; that is  sometimes torn  in luxa-
tion, and becomes an obstacle to the  easy  re-
duction of  the  bone.   Its lower  extremity is
articulated  with the bones of the  fore-arm. 
Osteology.
119
  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 small-
er as it descends to the wrist.  At its upper
part it has two processes and two cavities.  Of
the two processes, the largest,  which  is situ-
ated posteriorly,  and  called the olecranon, is
admitted into the posterior fossa of  the os hu-
meri.  The other process is placed anteriorly,
and is called the coronoid process.  In bending
the arm it enters into the anterior 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 be-
comes straight, and will  not permit the fore-
arm to be bent backwards.    The ligaments
likewise oppose this motion.
   Between the two processes we have  describ-
ed,  there is  a considerable  cavity called  the
sygmoid  cavity, divided into two  fossae by a
small  eminence,  which passes from one pro-
cess to the other;  it is by means of this cavity
and the two processes, that the ulna is articu-
lated with the os humeri by  ginglimus.
   At the bottom of the coronoid process interi-
orly, 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 
12(5
Osteology.
ulna  is articulated above to  the os humeri—
both  above and below to the radius, and to
the wrist  at its lower extremity.   All these ar-
ticulations are secured by means of ligaments.
The chief use of this  bone seems to be to sup-
port 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
somewhat larger than the ulna, but not quite
so long as that bone.   Its upper part is cylin-
drical, hollowed superiorly to receive the out-
er condyle of the os  humeri.  Laterally it is
admitted into  the little sygmoid cavity  of the
ulna, and the cylindrical part of the bone turns
in this cavity in the motions of pronation  and
supination.*  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 weaker below than
above ; so that they serve to supply each other's
deficiencies  in both those parts.
   On the external side  of this bone, we ob-
serve a small  cavity which is destined  to re-
ceive the lower end of the ulna; and its low-
er extremity is formed into a large  cavity, by
means of which it is articulated with the bones

  * The motions of pronation and supination may be easily
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 towards
the table, the hand will be then in a state of supination. 
Osteology.
121
of the wrist,  and on this account it is some-
times 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 affords
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 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 par-
ticular name.   The  names  he  adopted  are
founded on the figure of the  bones,  and  are
now pretty generally received, except the first,
which instead of ».ti,x.(<ac (the name given to it
by Lyserus, on account of its sinus  that ad-
mits a part of .the os  magnum),  has by later
writers  been named Scaphoides or Naviculars
This, which is the outermost 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 lu-
nare, and below  to the trapezium and  trape-
                     Q 
122
Osteology.
zoides.  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 cuneiforme, 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
articulated with  the ulna,  and anteriorly with
the os unciforme.
   These three bones form an oblong articulat-
ing 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 se-
cond  row correspond  with  the bones  of the
thumb  and fingers;  the  first, second,  and
fourth,  are from  their shapes named trapezi-
um, trapezoides, and unciforme ; the third, from
its being the  largest bone of  the carpus, is styl-
ed 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 ex- 
Osteology.
123
pansions, called the external  and internal an-
nular ligaments of the wrist.   The former ex-
tends in an oblique direction from the os pisi-
forme to the styloid process 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 unciforme, to the os sca-
phoides and trapezium.   These annular liga-
ments 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, and internally somewhat con-
cave, where they form  the palm of the hand.
They are hollow and of a cylindrical shape.
   At each  extremity they are a little hollow-
ed for their articulation ;  superiorly with the
bones of the carpus, and  inferiorly  with the
first phalanx of the fingers, in the same man-
ner 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 call-
ed 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. 
124
Osteology.
  It will be easily understood that this multi-
plicity of bones in the hand (for there  are  27
in each  hand) is  essential to the different mo-
tions we wish to perform.   If each finger was
composed only of one  bone instead  of three,
it would be impossible for us to grasp any
thing.

      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  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 cylindri-
cal  shape,  is convex before  and  concave be-
hind, where it serves to lodge several muscles.
  Throughout two-thirds of its length we ob-
serve a ridge called linea aspera,  which  origi-
nates from the trochanters, and after running
for  some way downwards,  divides into two
branches, that terminate 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 like-
wise two considerable  processes: the  head,
which  forms the greater portion of a sphere
unequally  divided,  is turned inwards,  and re-
ceived into the great cotyloid cavity  of the  os 
Osteology.
125
innominatum.  At this part of the bone there is a
little fossa to be observed, to  which the round
ligament is  attached, and which we have  al-
ready described as tending to secure the head
of this  bone in the great  acetabulum.   The
neck is almost horizontal, considered with re-
spect 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 at-
tachment 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  co-
tyloid cavity of the os innominatum,  and sur-
rounds 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 interme-
diate smooth  cavity, by  means of  which it is
articulated with the leg by ginglimus.
   All round the under end of the bone  there
is an irregular surface where the capsular  li-
gament of the joint has its origin,  and where
blood-vessels  go into the substance of  the
bone.
   Between the condyles there is a cavity pos-
teriorly, 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. 
126
Osteology.
   At the side of each condyle externally, there
is a  tuberosity,  from whence the lateral liga-
ments originate, which are extended down to
the tibia.
   A ligament likewise arises from each con-
dyle posteriorly.   One  of  these  ligaments
passes from the right to the left, and the other
from the left to  the  right, so that  they  inter-
sect each other,  and for that reason are called
the  cross ligaments.
   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
differently 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 downwards.
   It is thinner at its edge than in its middle
part; at  its  fore-part it is smooth  and some-
what convex;  its posterior surface, which  is
more unequal, affords an elevation in the  mid-
dle which is  admitted between the two  con-
dyles of  the os femoris.
   This bone is retained in its proper situation
by a strong ligament which every where  sur- 
Osteology.
127
rounds it, and adheres both to the tibia and os
femoris; it is likewise  firmly connected with
the tibia by means  of a strong tendinous liga-
ment of an inch in breadth,  and upwards of
two  inches in length,  which adheres to the
lower part of the patella, and to the tubero-
sity at the upper end of the tibia. On account
of this connection,  it is  very properly consi-
dered as an appendage  to  the tibia, which  it
follows in all its motions, so as 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 movea-
ble,  being capable of sliding from above down-
wards and from below upwards.  This mobi-
lity is essential 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 knee  from
external injury; it  likewise tends  to increase
the power of the extensor muscles  of the leg,
by removing 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
tibia; the other is  much  smaller,  and  named
fibula.
   The tibia,  which is  so  called from  its re-
semblance  to the musical pipe of the ancients, 
128
Osteology.
has three surfaces,  and is  not very unlike a
triangular 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 ex-
tremity 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 be-
tween the two condyles ; so that this articula-
tion affords  a specimen of the complete gin-
glimus.  Under the external edge of the up-
per end of this  bone  is a circular flat surface,
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 transverse cavity, by which it
is  articulated with the uppermost bone  of the
foot.   It has likewise another cavity at its low-
er end and outer side, which is somewhat ob-
long, 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 extremi-
ty 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. 
                  Osteology,              129

   Its lower extremity is stretched out into a
 coronoid process, which is flattened at its  in-
 side, and is convex  externally, forming what
 is called the malleolus externus or outer ankle.
 This is rather lower than the malleolus inter-
 nus 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, os calcis, os naviculare, os cu-
 boides, 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 se-
 veral  surfaces to be considered; its  upper,
 and somewhat posterior part, which is smooth
 and convex,  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 articulated with the os calcis, and  its  an-
 terior surface is  received by the  os naviculare.
 All these articulations are secured  by means
of ligaments.
                     R 
130              Osteology.
  The os calcis, or calcaneum, which is of a
very irregular figure, is the largest bone of the
foot.   Behind, it is formed into a considerable
tuberosity called the heel;  without this tube-
rosity, 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
observe a considerable sinuosity, which affords
a passage to the tendon  of a  muscle:  and to
the posterior part of the os calcis, a strong
tendinous cord called tendo achillis* is attach-
ed, which is formed by  the tendons of seve-
ral muscles united 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 ar-
ticulated with the cuneiform bones, and late-
rally 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 cu-
neiform bone and the os naviculare.
} Each  of the  ossa cuneiformia, which  are
three in number, resembles a wedge, and from
this similitude  their name is  derived.   They
  * This tendon is sometimes ruptured by jumping, dancing,
or other violent efforts. 
Osteology.
131
are placed next to the metatarsus by the sides
of each other, and  are  usually  distinguished
into os cuneiforme externum, medium or mini-
mum, and internum or maximum.  The supe-
rior surface of these bones, from their wedge-
like shape, is broader than that  which is be-
low, where they help to form the sole  of the
foot;  posteriorly they are united to the os na-
viculare, and anteriorly they support the three
first metatarsal bones.
   When these seven bones composing the tar-
sus are viewed together in the skeleton,  they
appear convex above, where they help to form
the upper part of the foot; and concave under-
neath, 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 capsular  and two  lateral liga-
ments ; each of  the latter is covered by an an-
nular ligament  of  considerable breadth  and
thickness,  which serves to bind down the ten-
dons  of the foot,  and at the  same time to
strengthen the articulation.
   The os cuneiforme externum  is joined late-
rally  to the os cuboides.
   These bones complete our account of the tar-
sus.  Though what we have said  of this part
of the osteology has been very simple and con-
cise,  yet many readers may not  clearly under-
stand it: but if they will be pleased to view
these bones  in  their proper situation in the 
132              Osteology.

skeleton, all  that we have said of them  will
be easily understood.
  The metatarsus 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 includ-
ed 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 re-
semble each other in  size.
  These bones are articulated by one extremi-
ty with the cuneiform bones and the os cuboi-
des,  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 fingers, yet they appear to be
perfectly fitted for the purposes they  are de-
signed for.  In walking, the toes  bring  the
centre  of gravity perpendicular to the advanc-
ed foot; and  as the soles of the feet are natu-
rally concave, we can at pleasure increase this
concavity,  and form  a kind of vault, which
adjusts itself to the different inequalities that
occur to us in walking; and which, without
this  mode of arrangement,  would  incommode
us exceedingly, especially when bare-footed. 
Osteology,
133
       4. Of the Ossa Sesamoidea.


  Besides the  bones we have already de-
scribed, 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  supposed  general resemblance to the
seeds of the sesamum, are called  ossa sesa-
moidea.  They are commonly 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 condyles of  the thigh-
bone, under the  os cuboides of the tarsus, and
in other parts of the body.  Their size and num-
ber seem constantly to be increased 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 por-
tions of ligaments or tendons.
   The upper surface of these bones is usual-
ly convex,  and adherent to the tendon that co-
vers  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 muscles.   In the great toe and
thumb they are  likewise useful, by forming a
groove for the flexor tendons. 
134              Osteology.
  EXPLANATION OF THE PLATES

           OF OSTEOLOGY.


               Plate.  XIX.

Fig. 1.   A Front-view  of the Male  Skele-
                   ton.
  A, The os frontis. B,  The os parietale. C,
The coronal suture.  D, The squamous part
of the  temporal bones.  E, The squamous su-
ture.  F, The zygoma.   G, The mastoid pro-
cess.  H, The temporal process of the sphe-
noid bone.  I, The orbit.   K, The os malae.
L, The os maxillare superius.  M, Its nasal
process.   N, The ossa  nasi.  O, The os un-
guis.  P,  The maxilla inferior.  Q,  The teeth
which are sixteen in number in each jaw.  R,
The seven cervical vertebrae, with their inter-
mediate cartilages.  S,  Their transverse pro-
cesses.   T,  The  twelve dorsal vertebrae, with
their intermediate cartilages.   U,  The five
lumbar  vertebrae.  V, Their transverse pro-
cesses. W, The upper part  of the os  sacrum.
X, Its  lateral parts.  The  holes seen on its
fore part  are the  passages  of the undermost
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
processes,  b,  The  brim of  the pelvis,  c 
fc


 
 
Osteology,              133
The  ischiatic niche,   d,  The os ischium,  e,
Its tuberosity,   f, Its spinous process,  g, Its
crus.  h, The foramen thyroideum.  i,  The
os  pubis,   k, The symphysis pubis.  1,  The
crus pubis,   m, The acetabulum,  n,  The se-
venth or last true rib.  o, The twelfth or last
false  rib.   p,  The upper end of the sternum.
q, The middle piece,  r, The under end, or
cartilage ensiformis.   s, The clavicle,   t, The
internal surface  of the scapula,   u, Its acro-
mion,  v, Its coracoid process,  w, Its cervix.
x, The glenoid cavity,   y, The os humeri, z,
Its head which is connected to the glenoid ca-
vity.   1,  Its external tubercle.  2, Its' inter-
nal tubercle.   3. The groove for lodging the
long  head of the biceps  muscle  of the  arm.
4, The internal  condyle.  5, The external
condyle.  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; cor. pos-
ed of os naviculare,  os lunare,  os cuneifor-
me, os pisiforme,  os trapezium, os trapezoi-
des, os magnum, os unciforme.  19, The five
bones of the metacarpus.  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 minor.  27,  The
internal condyle.  28, The external condyle
29, The rotula.  30, The tibia.   31, Its head-
32, Its tubercle.  33,  Its spine. 34,  The  mal-
leolus internus.  35, The  fibula.  36, Its head.
37, The  malleolus externus.   The tarsus is 
136              Osteology.
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.   4^, 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  temporal muscle.   C, The superciliary
ridge.    D, The  superciliary hole through
which the frontal vessels and  nerves pass. E
E, The orbitar processes.   F, The middle of
the transverse suture.  G, The upper part of
the orbit.  H, The foramen opticum.  I, The
foramen lacerum.  K, The inferior orbitar fis-
sure.  L, The os unguis.   M, The ossa na-
si.   N, The  os maxillare superius. O, Its na-
sal  process.   P, The external orbitar  hole
through which the superior maxillary vessels
and  nerves pass.  Q, The os malae.   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 spongi-
osum superius.   V, The os spongiosum infe-
rius.   W, The edge  of the alveoli, or spongy
sockets, for the  teeth-  X,  The maxilla infe-
rior.  Y, The passage for the inferior maxil-
lary vessels and nerves- 
Osteology*              137
     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 for-
wards, the temporal process of the sphenoid
bone.  G, The zygomatic process of the tem-
poral bone. H, The zygomatic suture. I, The
mastoid process of the temporal bone. K, The
meatus  auditorius externus.   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 superior maxilla-
ry bone.  Q, Its  nasal  process.  R, The two
dentes incisores.   S, The dens caninus.  T,
The two  small molares.  U, The three large
molares.  V,  The os malae.  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.  B B, The ossa parieta-
lia.   C, The  sagittal suture,  D, The parie-
tal  hple, through which a small vein runs to
the  superior longitudinal sinus.  E, The lamb-
doid suture.  F  F, Ossa  triquetra.  G, The
os occipitis.   H,  The squamous part of the
temporal bone.  I, The mastoid process.   K,
                    S 
138
Osteology.
The zygoma.  L, The os malae.  M, The tem-
poral part of the sphenoid bone.   N, The su-
perior maxillary bone and teeth.

Fig. 5.  The external Surface of the Os Fron-
                    tis.

  A, The convex part.   B,   Part of the tem-
poral fossa.  C, The external angular process.
D,  The internal angular process.   E, The na-
sal  process.  F, The superciliary  arch.  G,
The superciliary hole.   H, The orbitar plate.

Fig. 6.  The Interior Surface of the Os Fron-
                    tis.
  A A,  The serrated  edge  which assists to
form the coronal suture.   B,  The external an-
gular  process.  C,  The internal angular pro-
cess.  D, The  nasal process.  E,  1 he orbi-
tar  plate.  F, The cells which correspond with
those of  the ethmoid bone.   G, The passage
from the frontal sinus.  H, The opening which
receives  the cribriform  plate of the ethmoid
bone.   I, The  cavity 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 XX.

   Fig.  1. A Back-view of the Skeleton.
  A A,  The ossa  parietalia.  B,  The sagit-
tal  suture.  C,  The lambdoid suture.  D,The  • 
 
 
Osteology.
139
occipital bone.   E, The squamous  suture. F,
The mastoid  process of the temporal bone.
G,  The os malae.  H, The palate-plates of the
superior maxillary bones.  I, The  maxilla in-
ferior.   K, The teeth of both jaws.  L, The
seven  cervical  vertebrae.  M, Their  spinous
processes.  N, Their transverse  and oblique
processes.  O, The last of the twelve dorsal
vertebrae.  P, The fifth or last lumbar vertebra.
Q,,  The transverse processes.  R, The obli-
que processes.  S,  The spinous processes.  T,
The upper part of the os sacrum.  U, The
posterior  holes which transmit  small blood-
vessels and nerves.   V,  The under part of
the os  sacrum  which is covered by a mem-
brane.   W, The os coccygis.  X, The os ili-
um.  Y, Its  spine or crest.  Z, The ischia-
tic niche,   a, The os  ischium,  b, Its tubero-
sity,  c, Its spine, d, The os pubis,  e, The
foramen hydroideum.   f,  The seventh or last
true rib.  g,  The twelfth or last false rib. h,
The clavicle,   i, The scapula,   k, Its spine.
1, Its acromion,   m,  Its cervix,  n, Its supe-
rior costa.  o, Its posterior costa*   p, Its infe-
rior costa.   q, The os humeri,   r, The radi-
us.   S} The  ulna, t, Its oleclarnon.   u, All
the bones of the carpus,  excepting the os pi-
siforme,  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 
140              Osteology.
trochanter minor. 3, The lineaaspera.  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
                Parietale.
  A, The convex smooth surface-  B, The pari-
etal 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  coronal suture.   C. The inferior edge
for the squamous suture-  D,  The posterior
edge for the  lambdoid suture.  E, A depres-
sion made  by  the  lateral  sinus-   F F, The
prints of the arteries of the  dura mater.

Fig. 4. The External Surface  of  the Left Os
                Temporum.
   A, The squamous part- B, The mastoid pro-
cess.   C, The  zygomatic  process.  D, The
styloid process.  E, The petrosal process.  F.
The meatus auditorius externus.  G, The gle-
noid 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. 
Osteology.
141
K, The foramen mastoideum through which
a vein goes to the  lateral sinus-

Fig. 5- The Internal Surface of the Left Os
               Temporum.
  A,  The  squamous  part; the upper edge of
which assists in forming the squamous suture.
B, The mastoid process. C, The  styloid pro-
cess.  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 foramen mastoideum.

Fig- 6. The External Surface of the Osse-
  ous  Circle, which  terminates the meatus
  auditorius 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. 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- 
142
Osteology.
Fig. 9. The Malleus, with its Head, Handle,
           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  Crura.

Fig- 13- An Internal View of the Labyrinth
                of  the  Ear.
  A, The  hollow part of the cochlea, which
forms a share of the meatus  auditorius inter-
nus.  B, The vestibulum.  C C C, The semi-
circular canals.

Fig. J4- An External View of the Labyrinth-
  A, The semicircular canals. B, The fenes-
tra ovalis which  leads into the vestibulum. C,
The fenestra  rotunda which opens into the
cochlea. D, The different turns of the cochlea.

Fig. 15« The Internal Surface of the Os Sphe-
                 noides.
  A A, The temporal processes-  B B, The
pterygoid processes. C  C, The  spinous pro-
cesses.  D D, The  anterior clinoid processes.
E, The posterior clinoid process-  F, The an-
terior process 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 rotun- 
Osteology.
142
dum.   M, The foramen ovale.   N, The fora-
men spinale.

Fig. 16.  The  External  Surface  of  the  Os
               Sphenoides.
  A A, The temporal processes.  B  B, The
pterygoid processes.   C C,  The spinous pro-
cesses.  D,  The processus azygos.   E, The
small  triangular processes  which grow from
the body of the bone.  F F, The orifices of
the sphenoidal sinuses.   G, The  foramen la-
cerum.  H, The foramen rotundum.   I, The
foramen ovale.  K, The foramen pterygoide-
um.

Fig. 17. The External View of the Os Eth-
                 moides.
   A,  The nasal lamella.   B B, The grooves
between the nasal lamella and ossa spongiosa
superiora.  C C, The ossa spongiosa  superio-
ra.  D D, 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 ol-
factory nerves.  C  C, Some of the ethmoidal
cells.   D, The right os  planum.  E E, The
sphenoidal cornua-

Fig.  19- The right Sphenoidal Cornu.

Fig. 20. The  left Sphenoidal Cornu. 
144
Osteology.
Fig. 21. The External Surface of the Os Oc-
                  cipitis-
  A,  The  upper part of the bone.  B, The
superior arched ridge-  C,  The inferior arch-
ed ridge.  Under the arches are prints  made
by the muscles of the neck.   D D,  The two
condyloid processes which articulate the head
with the spine.   E, The cuneiform process.
F, The foramen  magnum  through which the
spinal  marrow passes.  G G,  The  posterior
condyloid foramina which transmit veins into
the lateral sinuses.  H H, The foramina lin-
gualia for  the passage  of the nine pair of
nerves.

Fig. 22. The Internal Surface of the Os Oc-
                 cipitis.
  A A, The two sides which assist to form
the lambdoid suture.  B, The point  of  the
cuneiform process,  where  it joins the  sphe-
noid  bone.   C C, The prints made by  the
posterior lobes of the brain-  D D, Prints
made by the lobes of the cerebellum. E, The
cruciform ridge for the attachment of the pro-
cesses of the  dura  mater.   F,  The course of
the superior longitudinal  sinuses-   G G,  The
course  of  the two  lateral  sinuses.  H,  The
foramen magnum. II, The  posterior condy-
loid foramina. 
Osteology.
145
              Plate  XXL


    Fig. 1» A Side-view of the Skeleton,

  A A, The ossa parietalia.  B, The sagittal
suture.  C, The os occipitis. D D, The lamb-
doid suture. E, The squamous part of the tem-
poral bone.  F, The mastoid process.  G, The
meatus  auditorius externus.  H, The os fron-
tis.  I,  The os malae.   K, The os maxillare
superius.   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
processes.   T, Openings between the verte-
brae for the passage of the spinal nerves.  U,
The under end of  the os sacrum.  V, The
os coccygis.  W, The os ilium.  X, The an-
terior 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  ischium,  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 bones of 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-
                     T 
146
Osteology.
 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 diploe.   B  B, The  orbitar plates of the
 frontal bone.  C, 1 he crista galli, with cribri-
 form plate of the ethmoidal bone on  each  side
 of it, through  which  the first pair  of nerves
 pass.  D, The cuneiform process of the occipi-
 tal bone.  E,  The  cruciform  ridge.  F,  The
 foramen  magnum for the passage of the spi-
 nal marrow.  G, The  zygoma,  made by the
 joining  of the  zygomatic processes of the os
 temporum and os malae.  H, The pars squa-
 mosa of  the os temporum.  I,  The pars mam-
 millaris.   K, The pars petrosa.   L,  The tem-
 poral  process of the sphenoid  bone.  M M,
 The anterior clinoid processes.   N,  The  pos.
 terior clinoid process.   O, The sella turcica.
 P, The  foramen opticum, for the passage of
 the optic nerve and ocular artery of the left
 side.  Q, The foramen lacerum, for the third,
 fourth, sixth, and first of the fifth pair of nerves
 and ocular vein.  R, The foramen rotundum,
for the second of the fifth pair.  S, The  fora-
men ovale, for the third of the fifth  pair. T,
The foramen spinale, for the principal artery
of the  dura mater.  U, The entry of the au- 
 
 
Osteology.
147
ditory 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
molares. D, The three large molares. E, The
foramen incisivum,  which  gives passage to
small blood-vessels and nerves. F, The palate-
plates of the ossa maxillaria and palati, joined
by the longitudinal  and transverse palate su-
tures.   G, The  foramen palatinur/i posterius,
for the  palatine vessels and nerves-   H, The
os maxillare superius of the right side. 1, The
os  malae.  K, The  zygomatic  process of the
temporal bone.  L, 'I he posterior extremity of
the ossa spongiosa.   M, The  posterior  extre-
mity of the vomer,  which forms the back-part
of the septum nasi.  N, The pterygoid process
of the right side of the sphenoid bone. O O, The
foramina ovalia.  PP, The foramina spinalia.
Q, Q, The passages of the internal carotid ar-
teries.  R, A hole between the point of each pars
petrosa and cuneiform process of the occipital
bone, which is filled up with a ligamentous sub-
stance 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 mag-
num. W, The inferior orbitar fissure. X, The
glenoid cavity, for the articulation of the low-
er jaw.  Y, The squamous part of the temporal 
148              Osteology.
bone.   Z, The mastoid process, at the inner
side of which is a fossa for the posterior belly
of the digastric  muscle,   a, The styloid pro-
cess,  b,  1 he meatus auditorius externus.  c,
The left condyle  of the occipital bone,  d, The
perpendicular  occipital spine,   e e, The infe-
rior horizontal ridge of the occipital bone,  ff,
The superior horizontal ridge, which is oppo-
site to the crucial ridge where the longitudinal
sinu> divides to form the lateral sinuses, ggg,
The lambdoid suture, h, The left squamous su-
ture,  i,  The parietal bone-

Fig. 4.  The  anterior  surface  of the  Ossa
                   Nasi.
  A, The upper part, which joins the os fron-
tis.  B,  The under end, which joins the car-
tilage of the nose.  C, The inner edge, where
they join each  other.

Fig. 5. The  posterior surface of  the  Ossa
                   Nasi.
  A A,  Their cavity, which forms part of the
arch of the nose.  B B,  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 Max-
      illare Superius of the left side.
  A,  The nasal  process.   B, The orbitar
plate.  C, The unequal  surface  which joins
the os  malae.  D,  The  external  orbitar hole.
E, The opening into the nostril.  F, The pa- 
Osteology,
149
late-plate.   G, The maxillary tuberosity.   H,
Part of the  os palati.  I, The two dentes inci-
sores.   K,  The dens caninus.   L, The two
small  dentes  molares.   M, The three large
dentes molares.

Fig. 7. The internal surface of  the Os Max-
     illare Superius and Os  Palati.
   A, The nasal process.  B B, Eminences for
the connection  of the os spongiosum inferius.
D, The under end of the lachrymal  groove.
E, The antrum maxillare. F, The nasal spine,
between which and B is the cavity of the nos-
tril.  G, The  palate-plate.   H,  The  orbitar
part of the  os palati.  I, The nasal plate.  K,
The suture  which unites the maxillary and pa-
late 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  irre-
gular, where it covers  part of the  ethmoidal
cells. 
150
Osteology.
Fig. 10. The external surface of the left Os
                  Malje.
  A, The superior orbitar process.  B, The
inferior orbitar  process.  C, The malar pro-
cess.   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
                  Mal^.
  A, The superior orbitar process.  B, The
inferior orbitar  process.   C, The malar pro-
cess.   D, The  zygomatic process.  E, The
internal orbitar plate or process.

Fig. 12. The external surface of the right Os
           Spongiosum  Inferius.
  A, The anterior part.  B,  The  hook-like
process for covering part of the antrum maxil-
lare.   C,  A small process which covers part
of the under  end of the  lachrymal groove.
D,  The inferior 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
palate bones.

Fig. 14. The posterior  and external surface
          of the right Os  Palati.
  A, The orbitar process.  B, The nasal la-
mella.   C, The pterygoid process. D, The
palate process. 
Osteology.
151
 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.   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
 lamella 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 pos-
 terior part which receives  the processus azy-
 gos of the sphenoid 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
 molares.
 Fig. 18.  The different classes of the Teeth.

  1, 2,  Afore and back view of the two ante-
rior dentes incisores of the lower jaw.   3,  4. 
152
Osteology.
Similar teeth of4 the upper jaw.   5,  6, A fore
and back view of  the  dentes  canini.  7, 8,
The anterior dentes molares. 9, 10, 11, The
posterior dentes molares.  12,  13,  14,  15, 16,
Unusual appearances in the shape and size of
the teeth.

Fig, 19. The external surface of the Os Hy
                   oides.
  A,  The body.   B B,  The cornua.   C C,
The appendices.


              Plate  XXII.


Fig. 1. A Posterior  View  of  the  Sternum
   and Clavicles,  with the ligament connect-
   ing the clavicles to each other.

   a, The posterior  surface of  the  sternum.
b b, The broken ends of  the clavicles, c c c c,
The tubercles near the extremity of each cla-
vicle,  d, The ligament  connecting the  cla-
vicles.

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 cos-   i
ta.  e,  Cervix,   f, Glenoid cavity,  covered
with  cartilage for  the  arm-bone,  g g, The
capsular  ligament  of the joint-  h, Coracoid 
 
 
Osteology.              153
process,  i,  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 process,   m, A ligament com-
ing out single from the acromion, and dividing
into two, which are fixed to  the coracoid pro-
cess-
Fig. 3.   The Joint of the Elbow of the Left
         Arm, with the Ligaments.

   a, The os humeri,  b, Its internal condyle.
c  c, The two prominent parts of its trochlea
appearing through the capsular ligament,  d,
The ulna,   e, The radius,   f,  The part of the
ligament 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 sca-
phoid bone of the carpus,   d, The os lunare.
e, The  os cuneiforme.  f,  The os  pisiforme.
g, Trapezium,  h,  Trapezoides.   i, Capita-
turn,  k,  Unciforme.  1,  The four metacar-
pal bones of the  fingers,   m,  The  first pha-
lanx,  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
figure ;  the  same letters pointing out the same
bones, though in a different view.
                     U 
154
Osteology,
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,  b b,
The parts of the extremity  of the  tibia, co-
vered with cartilage, which appear within the
semilunar cartilages,  c c, The semilunar  car-
tilages,   d,  The  two parts of what is called
the cross ligament.

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 se*-
milunar  cartilage,  g,  An oblique  ligament.
h, A larger perpendicular ligament,   i, A li-
gament  connecting the femur and fibula.

Fig. 8-  The  Anterior  View   of the  Joint of
             the Right Knee.
  b,  The internal condyle-    c, Its  external
condyle,  d, The part of the  os femoris, on
which the patella moves-  e, A perpendicu-
lar ligament,  f f, The two parts of the  cru-
cial ligaments,   g g, The edges  of the  two
moveable semilunar cartilages,  h, The tibia.
i, The strong ligament of the patella,  k, The
back  part  of it where  the fat has been  dis-
sected away.  1,  The external depression,   m,
The internal one.  n,  The cut tibia. 
Osteology.
155
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
prominence  on its outside,   c,  The  hollow
for  the tendons, nerves, and blood-vessels,  d,
The anterior 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 internum ; k,—Medium ;
1,—Externum,  m, The metatarsal bones of
the four lesser toes,  n, The first—o,  The
second—p,  The third phalanx of the four les-
ser 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. 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 pol-
licis and digitorum  longi opened,  d,  The
strong  cartilaginous ligament supporting the
head of the astragalus,   e, h, Two ligaments
which  unite  into  one,  and  are  fixed to the 
156
Osteology.
metatarsal bone  of the  great toe.   f, A liga-
ment from the knob  of the  os calcis 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 figamentum rotundum  con-
necting it to  the acetabulum,   c, The capsu-
lar ligament of the joint with  its arteries in-
jected,   d, The numerous vessels of the  mu-
cilaginous 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.  b  b, Its  cornua.   c, The appendix
of  the  right side,  d,  A  ligament  sent out
from the appendix  of the left side, to the sty-
loid process  of the  temporal bone,  e, The
union of the base  with the left cornu.  f f,
The posterior sides of (g) the thyroid  carti-
lage,  h h, Its  superior  cornua.  i i, Its in-
ferior cornua.  k,  The  cricoid cartilage.  11,
The arytenoid cartilages,   m, The entry into
the  lungs, named  glottis,  n, The epiglottis.
o o, The  superior cartilages of the trachea.
p, Its ligamentous back part.
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  liga-
 mentous substance in which they are formed. 
Of the Integuments, &c.       157
Part II.  OF THE SOFT PARTS IN GE-
                NERAL ;


Of the Common Integuments, with their appen-
         dages ;  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 dis-
tinctly,  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 impossible to convey a just
idea of any  one of them, without being in some
measure obliged to say something of others;
and on this  account 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 in-
 teguments,  and after them the muscles will be
 described;  we then -propose to  enter into an
 examination of the several viscera and their
 different functions.  In describing the brain. 
158       Of the Integuments, &c.

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 intro-
duced in their proper places.
   The body is divided into three great cavities.
Of these the uppermost is formed by the bones
of the cranium, and incloses the brain and cere-
bellum.
   The second is composed of the vertebrae of
the back, the sternum, and true ribs, with the
additional 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  vertebrae, the os  sacrum, the os-
sa innominata, and the false ribs,  to which we
may  add the peritonaeum,  and  a variety of
muscles.  This cavity 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 adi-
posa—The  hair and nails, as well as the se-
baceous  glands, may be  considered as appen-
dages to the  skin. 
Of the Integuments, csft.       159
           Sect.  I. Of the Skin.


            1. Of the ScART-skin.

  The epidermis,   cuticula, or  scarf-skin, is
a fine, transparent, and insensible pellicle, des-
titute of nerves  and blood-vessels,  which in-
vests the  body, and every where covers the
true skin.  This scarf-skin, Which seems  to
be very simple,  appears, when examined with
a microscope, to be composed  of several la-
minae or scales  which are  increased by pres-
sure, 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 mi-
nute 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 the body, which gradually hardens
when it comes into contact with the air.  They
were perhaps 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 appearing to be renewed on all
parts of the surface at the same  time; where-
as other parts which have been injured,  are
found to direct their growth from their  circum-
ference only towards their centre.  But a demon-
strative proof  that  the  epidermis is not a fluid 
160       Of the Integuments, &fc.

hardened by means of the external air, is that
the foetus in utero is found to have this cover-
ing.   Lieuwenhocck supposed its formation to
be owing to  the expansion of the extremities
of the excretory vessels which are found eve-
ry where  upon the surface of the true  skin.
Ruysch attributed  its origin  to  the  nervous
papillae of the skin; and Heister thinks it pro-
bable, that it  may  be owing both  to the  pa-
pillae  and the excretory vessels.   The  cele-
brated Morgagni, on the other hand, contends,*
that it is nothing more than the surface of the
cutis, hardened and rendered insensible by the
liquor amnii in vitero, 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  num-
ber of pores  or little holes,  which  afford a
passage to the hairs, sweat, and insensible per-
spiration,  and likewise to warm  water,  mer-
cury, and whatever  else  is capable  of being
taken in by the absorbents of the skin.   The
lines  which we observe on the epidermis be-
long to the true skin.  The cuticle adjusts it-
self 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 muco-
sum,  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
        * Adversar. Anat. u. Animadver. 2. 
           Of the Integuments, &c.       161

nothing more than a mucous substance which
may be dissolved by macerating, it in water,
while  the cuticle and cutis preserve their tex-
ture.
   The colour of the  body is found to depend
on the colour of this rete mucosum ; for in ne-
groes 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 the Cutis, or True Skin.

   The cutis is  composed of  fibres  closely
compacted together, as we may observe in lea-
ther,  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 sur-
face, innumerable papillae,  which  appear  like
very minute granulations, and seem to be  cal-
culated 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.
                     X 
162       Of the Integuments, &c.

  These  papillae  are  supposed by many ana-
tomical writers to be continuations of the pul-
py substance of nerves, whose coats have ter-
minated in  the cellular texture of the  skin.
The  great  sensibility of  these  papillae evi-
dently proves them to be exceedingly nervous;
but surely the  nervous fibrellae of the skin are
of themselves scarcely equal to the formation
of these papillae, and it seems to be more pro-
bable that they are formed like the rest of the
cutis.
  These  papillae 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 for-
mer 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,
within the substance of the skin,  with certain
glands or follicles, which discharge  a fat and
oily humour that serves  to lubricate and soft-
en the  skin.   When  the  fluid  they  secrete
has acquired a certain degree of thickness, it
approaches  to  the colour and  consistence of
suet; and from this appearance they have de-
rived their  name of  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 de- 
           Of the Integuments, &c.       163

scribed as  small spherical bodies placed in all
parts of the skin,  in much greater abundance
than those just now mentioned, and named mi-
liary, from their supposed resemblance to mil-
let-seed.   Steno,  who first  described these
glands, and Malpighi,  Ruysch, Verheyen,
Windslow, and others, who have adopted his
opinions on this subject, speak of them as  hav-
ing excretory ducts, that open  on the  surface
of the cuticle, and distil the  sweat and  mat-
ter of insensible perspiration ; and  yet,  not-
withstanding the positive manner in which these
pretended glands have been spoken of, we are
now sufficiently convinced that their existence
is altogether 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 everywhere dis-
persed through the skin.  These exhaling ves-
sels are easily demonstrated in the  dead  sub-
ject, by throwing 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 
164       Of the  Integuments, &c.

the cuticle,  and transmitting this fluid ; but in
this he was  mistaken.
   When the perspiration is by any means in-
creased,  and several drops that  were insensi-
ble when separate, are united together and con-
densed by  the  external air, they form  upon
the skin small, but visible, drops called sweat.*
This particularly happens after much exercise,
or whatever occasions an increased determin-
ation of fluids  to  the  surface of the body;  a
greater quantity 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
insensible perspiration and  sweat  are to be
considered as one and the same excretion, dif-
fering only in  degree;  or  whether they are
two  distinct excretions  derived from different
sources.   In  support  of the latter opinion,  it
has  been alleged,  that  the  insensible  perspi-
ration is agreeable to nature,  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 emuncto-
ry  through which the redundant water, and

  * Lieuwenhoeck asserts that one drop of sweat is formed by
the conflux of fifteen drops of perspirable vapour. 
           Of the Integuments, &c.        165

sometimes  the other more  saline parts of the
blood,  are  carried off. But  the insensible per-
spiration 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 exhaled from the human body by this
insensible  perspiration  is  very  considerable.
Sanctorius* an Italian physician, who indefati-
gably passed a great many years in a series of sta-
tical 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 aliment 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, urine, saliva,
&c.   But  in countries  where   the  degree  of
cold is greater  than in Italy,  the quantity 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 observ-

   * The insensible perspiration  is sometimes distinguished by
the name of  this physician, who was born in the territories of
Venice, and was afterwards a professor in the university of Pa-
dua.  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 insensible 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 li-
quid aliment increased or diminished it.  From these experi-
ments he formed a system, which he published at Venice in 1614,
in the form of aphorisms,  under  the  title of " Ars dc Medicina
Statica." 
 166       Of the Integuments, £jfc.

ed  to  vary  according to the season  of  the
year, and according  to  the constitution,  age,
sex, diseases,  diet, exercise, passions, &C. of
different people.
  From what has been said on this subject, it
will be easily conceived, that this  evacuation
cannot be either much increased or diminish-
ed in quantity  without affecting the health.
  The perspirable matter and the sweat are in
some  measure  analogous to the urine, as  ap-
pears from their taste and saline nature.* And
it is worthy of  observation, that  when either
of these secretions is  increased in quantity,
the other is diminished ;  so that they who per-
spire the least, usually pass the greatest quan-
tity 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
papillae of the skin: Ludwig, on the other hand,
maintained, that they were composed of  the
extremities of blood-vessels and  nerves; both
these opinions are now deservedly rejected.
  They seem  to  possess many properties in
common with the cuticle; like it they are nei-
ther vascular nor sensible,  and when the cuti-

  * Minute chrystals have been observed to  shoot upon the
clothes of men who work in glass-houses. Haller Elem. Phys. 
           Of the  Integuments, &c,        167

cle is separated from the true skin by macera-
tion or other means, the nails come aw< y with
it.
   They  appear to  be composed of  different
layers, of unequal size, applied  one over  the
other.   Each layer seems to be formed of lon-
gitudinal fibres.
   In each nail we may distinguish three  parts,
viz. the root, the  body or middle, and the ex-
tremity.  The root is of a soft, thm, and  white
substance, terminating in the form of a  cres-
cent ; the epidermis adheres very  strongly to
this part; the body of the nail is broader, red-
der, and thicker,  and  the extremity is of still
greater firmness.
   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
injury.

               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.*  Some

  * Malpighi, and  after him the celebrated Ruysch, supposed
the hairs to be continuations of nerves, being of opinion that
they originated from the papillae of the skin, which  they consi-
dered 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 rejected this doctrine, and con-
sider the hairs as particular bodie-, not arising from the papillae
(for in the parts  where  the papilla: abound  most there  are n0
hairs,) but from bulbs or capsules, which are peculiar to them. 
 168       Of the  Integuments, &c.

 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
 below by a regular propulsion from their root,
 where they receive their 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 consist of two  membranes,
 between which there  is a certain quantity of
 moisture.  Within the bulb  the hair separates
 into three  or four  fibrillae; 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 temperament of
 body.*
   Their general use in the body does not seem
 to be absolutely determined; but hairs  in par-
 ticular 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 the Cellular Membrane and Fat.

  The  cellular membrane is found  to  invest
 the most minute fibres we  are able to trace; so
that by  modern physiologists, it is  very pro-

  *  The hairs differ likewise  from  each other,  and may not be
improperly divided into two classes  ; one of which may include
the hair of the  head, chin, pubes, and axillse; and the other, the
softer hairs, which  are to be observed  almost every where on
the surface of die body. 
           Of the Integuments, &c.       169

perly considered as the universal connecting
medium 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 commu-
nication ;  for in the emphysema all its  cells are
filled with air,  and in  the  anasarca  they are
universally distended with water. Besides these
proofs of communication from disease, a fa-
miliar  instance  of  it may be observed  among
butchers, who usually puncture this membrane,
and by inflating it with air add to the good ap-
pearance of their meat.
   The cells of this  membrane  serve  as re-
servoirs to the  oily part of the blood or  Fat,
which seems to be deposited in  them, either
by transudation  through the coats of the ar-
teries,  that ramify  through these cells, or by
particular vessels, continued from the ends of
arteries.  These cells  are not of a glandular
structure,  as Malpighi  and others after  him
have supposed.   The fat is absorbed and car-
ried  back into the  system by the lymphatics.
The great waste of it in many diseases,  par-
ticularly in the  consumption,  is a  sufficient
proof that such  an absorption takes place.
   The fulness  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 graminivo-
rous animals, it  is found to be of  a firmer  con-
sistence than in  man.
                     Y 
170           Of the Muscles.
  The fat is not confined  to  the  skin alone,
being met  with every where in the interstices
of muscles, in the omentum,  about the kid-
neys, at  the basis of the heart, in the orbits,

  The chief uses  of the  fat.  seem to be  to
afford  moisture to all the parts with which it
is connected;  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,  suscepti-
ble of contraction and relaxation ; the motions
of which in a natural and healthy state, are
subject to the will, and for this  reason they
are  called  voluntary  muscles.  But besides
these, there are other parts of the  body that
owe their  power of contraction to  their  mus-
cular fibres ; thus  the heart is of a  muscular
texture,  forming what is called a hollow  mus-
cle ; and the urinary  bladder, stomach, intes-
tines,  &c. are enabled  to  act upon their con-
tents,  merely because they are provided with
muscular fibres.  These are called involuntary
muscles, because their motions are not depen-
dent on  the will.  The muscles of respiration,
being in  some measure influenced by the wiu\
are said  to have a mixed motion. 
Of the Muscles.           171
  The names by which the voluntary muscles
are distinguished, are founded on their size,
figure,  situation, use, or  the  arrangement of
their fibres, or their origin and insertion. But
besides these particular distinctions, there are
certain  general ones that require to be noticed.
  Thus,  if the fibres of a muscle are placed
parallel to each other in  a straight direction,
they form what are styled a rectilinear muscle ;
if the fibres cross and intersect each other, they
constitute 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 re-
spect to the tendon.
  Muscles that act in opposition to each other,
are called antagonista; thus every extensor
muscle has a flexor for its antagonist, and vice
versa.  Muscles that  concur in the  same  ac-
tion are styled congeheres.
  The  muscles being attached to the  bones,
the latter may  be considered as levers that  are
moved  in different directions  by  the contrac-
tion of those organs.
   The  end of a muscle which adheres to  the
most fixed part is  usually  called the  origin,
and 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,
sensible and irritable, edAXed fleshy fibres;  the
other of a firmer texture,  of a white  glisten-
ing  colour, insensible,  without irritability or
the power of contracting, and named tendinous 
172          Of the Muscles.
fibres. They are occasionally intermixed ; but
the fleshy fibres generally prevail in the belly
or middle part of a muscle, and the tendi-
nous ones in the extremities.   If these tendi-
nous  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 surface, the extremity
of the muscle is styled aponeurosis.
   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 muscles, and even  several mus-
cles,  covered by  a fascia of the same kind,
that affords origin to many of their fibres, dip-
ping  down between them, adhering to the
ridges of 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 thigh.
   Each  muscle  is inclosed by a thin covering
of cellular  membrane, which has been some-
times improperly considered as peculiar to the
muscles, and described under the name of pro-
pria  membrana musculosa.   This cellular co-
vering  dips down into  the  substance of the
muscle,  connecting and  surrounding the  most
minute fibres we  are able to demonstrate, and
affording a support to their vessels and nerves.
   Lieuwenhoeck fancied he had discovered, by 
Of the Muscles,           173
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 fasci-
culi 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 ani-
mals, is owing to an  infinite number of blood-
vessels that are dispersed through their sub-
stance.   When we macerate the fibres of  a
muscle in water, it becomes of a white colour
like all other parts of the  body divested of
their  blood.  The  blood-vessels  are accompa-
nied by nerves, and they are both distributed in
such  abundance to these parts, that in endea-
vouring to trace the course of the blood-ves-
sels in a muscle, it would appear to be formed
altogether by their ramifications ; and  in an
attempt to  follow  the branches of its nerves,
they  would be found to be  equal in  propor-
tion.
   If  a  muscle  is  pricked or irritated,  it im-
mediately contracts.  This is called its irrita-
ble principle ; and this irritability is to be con-
sidered 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. 
174           Of the Muscles.
This  power, which  disposes the muscles to
contract when stimulated,  independent of the
will, is supposed to- be inherent in them ;  and
is  therefore named vis insita.   This property
is not to be confounded with elasticity, which
the membranes and  other parts  of the body
possess in a greater or less degree in common
with  the  muscles;  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 re-
laxes again.  We may likewise produce such
a  contraction, by  irritating the nerve leading
to a muscle, although the nerve itself  is not
affected.
   This principle  is  found to  be  greater in
small than in large,  and in young than in  old,
animals.
   In the voluntary muscles these effects of con-
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 nervea,  was  the doctrine taught  by Doctor
Haller in  his Elem.  Phys. but is  at present
called in question by several, particularly Doc-
tor Monro, we think it necessary  to give a few
objections,  as  stated  in his  Observations on
the Nervous System: 
Of the Muscles.           175
  " The  chief experiment  (says the Doctor)
which  seems  to  have led Dr.  Haller to this
opinion, is the well known one, that the heart
and other muscles, alter being detached from
the brain, continue  to  act  spontaneously, or
by stimuli may be roused into action for a con-
siderable  length  of time ; and when it cannot
be alleged, 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 ener-
gy  can be put  in motion,  must perhaps  be
granted:  But has Dr. Haller given a better
explanation of the manner  in  which his sup-
posed vis insita becomes 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 hew  power,  instead of relieving,  would
add to our perplexity.
  "  We  should  then have admitted, that two
causes  of a different  nature were  capable of
producing 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 weak-
en the  credibility of it.  For instance, if in  a
sound animal the vis nervea alone produces
the contraction  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 
176           Of the Muscles.

that the nerves are the internuntii; and so ad-
mit two wise agents employed in every the most
simple action ? But instead of  speculating far-
ther, let us learn the effect of experiments,
and endeavour from these to draw plain conclu-
sions.
  "  1.  When I poured a solution of opium in
water under the skin of the leg of a frog, the
muscles, to the surface of which it was appli-
ed,  were  very soon deprived  of the power of
contraction.  In like manner, when I poured
this  solution  into the  cavity of the heart, by
opening the vena cava, the heart was almost
instantly deprived of its power of motion, whe-
ther the experiment was performed on it fixed
in its place, or cut out of  the  body.
  u  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 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 minutes the  most distant muscles of the
limbs  were extremely weakened.   Yet this
weakness was not owing to the want of circu-
lation, 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
sympathy  of  the brain,  and  of  the  nervous 
              Of the Muscles.           177

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 nee-
dle,  the muscle  in which  it terminates con-
tracts violently, exactly in the same manner as
when the  irritation is applied to the fibres of
the muscle.  But when the hot iron,  or nee-
dle,  is confined to the nerve,  Dr. Haller him-
self  must have  admitted, that the vis  nervea,
and  not the vis insita, 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 irri-
tation is applied to the muscle as when it is ap-
plied to the trunk of the  nerve, the impelling
power  of  the  mind seeming to  be  equally
wanting in both cases ?
  "  Secondly,  If it appears that irritation ap-
plied to the trunk  of a  nerve excites the vis
nervea, why should we doubt  that it can equal-
ly well excite it when applied to the  small and
very sensible branches  and terminations of the
nerve in the muscle ?
  "  As, therefore,  it appears that the suppos-
ed  vis  insita is destroyed or excited by  the
same means as the vis nervea; nay, that when,
by the  application of opium to the heart of  a
frog, after the  aorta is cut and the circulation
interrupted, we have destroyed the vis insita,
the vis  nervea is so much  extinguished, that
the animal cannot act with the distant  muscles
                     Z 
178           Of the Muscles.
of the limb;  and  that these afterward  grow
very  torpid, or lose  mucii 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 mus-
cle."
   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 perpe-
tual,  like this latter property.  After long con-
tinued or violent exercise, for example, the vo-
luntary muscles become painful,  and at length
incapable of further actipn ;  whereas the heart
and other involuntary muscles, the motions of
which depend solely on the vis insita, continue
through life in a constant state of action,  with-
out any inconvenience or waste of this inherent
principle.
  The action of the vis nervosa on the volun-
tary  muscles, constitutes what is  called mus-
cular  motion ; a subject that has given rise to
a variety of hypotheses,  many of them  inge-
nious, but  none of them satisfactory.
  Borelli and some others have undertaken to
explain the cause  of contraction,  by suppos-
ing that every muscular fibre forms as it were '
a chain of very minute bladders, while the
nerves which are distributed through the  mus-
cle, bring with them  a supply of  animal spi-
rits, which  at our will fill these bladders, and
by increasing their diameter in width, shorten
them, and  of course the whole fibre. 
              Of the Muscles.           179

  Borelli  supposes these bladders to be of a
rhomboidal  shape;  Bernoulli  on the other
hand contends that they are oval.  Our coun-
tryman, Cowper, fancied  he had filled them
with mercury ; the cause  of this mistake  was
probably  owing  to the mercury's insinuating
itself into some of the lymphatic vessels.  The
late  ingenious Mr. Elliot undertook to account
for the phenomena of muscular motion on prin-
ciples very different from  those just now men-
tioned.   He  supposed that a dephlogisticated
state of the blood is  requisite for muscular ac-
tion, and that a communication of phlogiston to
the blood is  a necessary effect of such action.
   We know that the muscular fibre is shorten-
ed,  and  that the muscle  itself swells when in
action ; but how these phenomena are produc-
ed,  we are unable to determine.  We likewise
know that the nerves are  essential to muscu-
lar  motion;  for  upon dividing or making a li-
gature round the nerve  leading to a muscle,
the  latter becomes incapable of motion.  A li-
gature  made on  the artery of a muscle  pro-
duces a  similar  effect; a proof this, that  a re-
gular supply of blood is also equally necessa-
ry to muscular  motion.   The  cause of palsy
is usually not  to be sought for in the muscle
affected,  but in the nerve leading to that  mus-
cle, or in that part of the brain or spinal mar-
row from which the nerve derives its origin. 
180           Of the Muscles.
          Of the particular Muscles.

  As the enumeration and description of the
particular muscles  must  be dry and unenter-
taining  to the generality of readers, yet can-
not be  altogether  omitted  in  a  work  of this
nature,  it appeared eligible to throw this part
of the subject into the form of a table ;  in
which the name, origin, insertion, and princi-
pal use  of each  muscle, will be found describ-
ed in few words, and occasionally its etymolo,
gy when it is of Greek derivation or difficult
to be understood. 
   A  TABLE of the  MUSCLES,  arranged according to  their Situation.



[N. B. This table does  not  include all  the muscles of the  body; thofe belonging  to the eyes,  internal car, intestinum
  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) are in pairs, mention is
  here made only of the muscles of one side.]
Muscles   situated
   unJtr the integu-
   m n s of the cra-
   miun   •   -
-  i
Name.
Occipito frontalis.
2. Corrugator super-
  cihi.
      Origin.


From the transverse
  ridge of the os oc-
  cipitis.
From above the join-
  ing of the os fron-
  tis, os nasi, and os
  maxillare.
     Insertion.


Into the  skin of the
  eye-brows.
Into the inner part
  of  the   occipito-
  frontalis.
Use.
To pull  the  skin of
  the  head   back-
  wards, and to raise
  the eye-brows and
  skin of  the  fore-
  head.
To  draw  the  eye-
  brows towards each
  other, and to wrin-
  kle the forehead. 
                          Name.
------------of the
 eye-lids            I. Orbicularis palpe-
                      brarum.

                    2. Levator palpebral
                      superioris.
-------—-of the
 external ear         i.  Attollens auricu-
                      1a.m.
                                  r:
                    2. Anterior auriculx.
                     3. Retrahentes ( *) au-
                       riculx.

Musclbs of the car-
  tilages of the ear   i. Tragicus.
       Origin.

From   around  the
  edge of the orbit.

From the bottom of
  the orbit, near the
  optic foramen.

From  the  tendon of
  the  occipito  fron-
  talis  near  the os
  temporis.
From  near the back
  part of the zygoma.

From  the  outer and
  back part of  the
  root of the mastoid
  process.
From  the  outer and
  middle part of the
  concha,  near  the
  tragus.
Insertion,
Use,
Into the nasal pre-  To shut the eye.
  cess   of  the  os
  maxillare.
Into the  cartilage of  To open the eye,
  the upper  eye-lid.


Into the upper part  To raise the ear.
  of the ear.
09
to
Into an eminence be-
  hind the helix.

Into the convex part
  of the  concha.
To raise  this  emi-
   nence, and to pull
   it forwards.
To stretch  the con-
   cha,  and pull  the
   ear backwards.
Into the upper part  To depress  the  con-
  of the tragus'.          cha,  and pull the
                        point of the tragus
                        a little outwardi,

to
* These *re three small ilcndcr muscles.  The inferior one i» sometime* wanting 
-ofthenose,
       Name.

i. Antitragicus.
3. Transversus-auri-
  culae.
4. Helicis major.
Heli
icis minor,
1.  Compressor
  naris.
(*)
       Origin.

From the root of the
   inner  part of the
   helix.
From the upper part
   of the concha.
From theupper, ante-
  rior, and acute part
  of the he'ix.
Frcm the  lower and
  fore part of the he-
  lix.
From the  outer part
  of the root of the
  ala nasi.
Insertion.
Use.
Into the upper part  To dilate the mouth
  of the anti-tragus.    of the concha.
Into  the  inner part
  of the helix.
Into the cartilage of
  the helix,  a  little
  above the tragus.
Into the helix, near
  the  fissure  in  its
  cartilage.
Into the  naval pro-
  cess of the os max-
  illare, and anterior
  extremity of the os
  nasi.
To stretchthe conclia
   and  scapha,  and
   likewise to pull the
   parts it is connect-
   ed  with  towards
   each other.
To depress the upper
   part of the helix.

To  ccntract  the fis-
   sure.

To straighten the nos-
   trils, and likewise
   to  conugate  the
   skin of the nose.

Co
  * The nose is affected by fibres of the occipito frontalis, and by several muscles of the face \ but this pair, the compressores, is  the    qq
only one that is proper to it.                                                                                          C3 
                          Name.
.----------of the
 mouth and lips,    i. Levator labii supe-
                     riors, alasque nasi.
2.  Levator   anguli
  oris.
3. Zygomaticus ma-
  jor.
4. Zygomaticus mi-
  nor.

c. Buccinator.
       Origin.

From the  outer part
  of the orbitar pro-
  cess of the os max-
  illare and from the
  nasal process  of
  that b me, where it
  joins the os frontis.
From the  os  maxil-
  lare superius, be-
  tween  the  orbitar
  foramen and  the
  first dens molaris.
From the  os  malas
  near the zygoma-
  tic suture.
Immediately  above
  the origin of  the
  zyg. major.
From the alveoli of
  the dentes molares
  in the upper  and
  lower jaws.
      Insertion.

Into the upper lip and
  alaof theno'-.e.
Into the orbicularis
  oris at the angle of
  the mouth.
Into the angle of the
  mouth.
Into the angle of the
  mouth.

Into the angle of the
  mouth.
        Use.

To draw  the  upper
   lip and  skin of the
   nose upwards and
   outwards.
To raise the corner
  of the mouth.
To raise the angle of
   the  mouth,  and
   make  the  cheek
   prominent,  as in
   laughing.
To raise the angle of
   the mouth oblique-
   ly outwards.
To contract the mouth
   and draw the angle
   of  it outwards and
   backwards. 
&

    Name.

Depressor labii su-
per i oris,   alacque
nasi.
Depressor
oris.
anguli
8. Depressor labii in-
  ferioris.
 Levator labii infe-
rioris.
       Origin.

From  the os maxill.
  super, immediately
  above the gums of
  the dentes incisores.
At the side of  the
   chin from the low-
   er edge of the max-
   illa inferior.
From  the  lower and
   anterior  part  of
   the  maxilla  inferi-
   or.
From near the gums
   of the incisores and
   caninusof the max-
   illa  inferior.
      Insertion.

Into the root of the
  ala nasi and upper
  lip.

Into the angle of the
  mouth.
Into the under lip.
Into  the  under lip
  and  skin  of  the
  chin.
        Use.

To draw the ala nasi
  and upperlip down-
  wards.

To draw the  corner
  of the mouth down-
  wards.

To draw  the under
  lip  downwards and
  somewhat outwards

To raise  the under
  lip  and skin of the
  chin.

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jo.  Orbicularis
  ris.  (*)
O-
To shut the mouth by
constraining the lips.
  (*) This muscle is in a great measure, if not wholly, formed by the buccinator, tygomatici, depressores, Mid other muscles that
move the hps.  Its fibres surround the mouth like a ring.
CO 
fyfuscLEs of the low-
  er jaw,   -   -  -
       Name.

i.  Temporalis,
2. Masseter.(f)
       Origin.

From part of the os
  bregmatis and os
  frontis;  squamous
  part of the os tem-
  poris ; back part of
  the  os make, and
  the  temporal  pro-
  cess of the os sphe-
  noides. (*)
From  the malar pro-
  cess of the os max-
  illare, and the low-
  er edges of  the os
  malae.  and  of the
   zygomatic process
  of the os temporis.
Insertion.
Use.
Intothe coronoid pro-,  To move  the  lower
  cess  of the  lower    jaw upwards.
  jaw.
coronoid  process,
and that part of the
j aw which supports
that and the con-
dyloid process.
to move the jaw a
little forwards and
backwards.
c*
3
Into the basis of the  To raise and likewise    ^
  (♦)  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, con-
verging and forming a strong middle tendon.
  (t) So called from its use in chewing, its derivation being from n*TtT*tt**: manduc», " H eat." 
       Name.

3.  Pterygoideus in-
  ternus.
,  Pterygoideus  ex-
 ternus.
--------situated at
 the fore part of the
 neck.
1 .Latissimuscolli. (f)
      Origin.

From  the inner sur-
  face  of the outer
  wing of the ptery-
  goid process of the
  os sphenoides, and
  from the process of
  the  os palati  that
  helps  to  form the
  pterygoid  fossa.
From the external ala
  of  the  pterygoid
  process,   a small
  part ofthe adjacent
  os maxillare, and a
  ridge in the ten po-
  ral process  of the
  os sphenoides.
From   the  cellular
 membrane covering
       Insertion.

Into the  lower  jaw
  on  its  inner  side
  and near its angle.
         Use.

To raise  the  lower
  jdv-  and  *mw it a
  little to one  side.
Into the fore part of  To move the jaw for-    ££
the  condyl id pro
cess « f the  lower
jaw,  and  likewise
of the capsular li-
gament.
Into  the  side of the
  chin  and intejm-
wards and to the
opposite side ; , * )
and at  the  same
time to prevent the
ligament  of  the
joint  fr"m  being
pinched.
To draw the cheeks
   and skin of the face
  (*) This happens when the muscle acts singly. When both act, the jaw is brought horizontally forwards.
  (+) 'Ihisbioad and thin muscular expansion, which i* situated immediately under the common unc; ur.ents, 15 by Winslow named
mucuhu cutaneus.  Galen gave it  the name of ^«r„^» ^t.s (Flatysma-myoides J ;  the etymology of wh.ch is from •fc-T..^ dUatati,,
and mvs,  musculus, and n&*s> forma.
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Co.
CO 
Name.
Z. Mastoideus (*).
Muscles fituated be-
  tween  the  trunk
  and the os hyoides.
,Omo-hyoideus(f).
    Origin.

the  pectoral, del-
toid, and trapezius
muscles.
From the upper part
  of the sternum  and
  from the upper and
  fore  part  of  the
  clavicle.
From the upper costa
  of the scapula near
  its niche; from part
  of a ligament that
  extends across this
  niche, and  some-
   Insertion.

ments of the cheek.
Into the mastoid pro-
  cess,  and  as far
  back as the lamb-
  doidal suture.
Into the basis of the
  os hyoides.
        Use.

   downwards;  and
   when the mouth is
   shut, to  draw  ;ill
   that part of the skin
   to which it is con-
   nected  below the
   lowerjawupwards.
To move the head to
   one  side, or when
   both muscles ;ct,to
   bend it forwards.
To draw the os hyoi-
   des  in  an oblique
   direction   down-
   wards.
CO
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  (•)  This, on account of its two origins, is by Albinus described as two distinct muscles, which he names stemo-mastoideus and deido-
mastoideus.
  (■p  This muscle does not always arise from the coracoid process, it seems to have been improperly named coraco-byoiJes by .Louglaa
and Albinus. Winslow calls it omo-hyoideus, on account of its general origin from the scapula. 
Name.
t. Sterno-hyoideus.
3. Hyo-thyroideus.
4. Sterno-thyroideus.
5. Crico-thyroideus.
Origin.
Insertion.
Use.
  times by a few fi-
  bres, from the co-
  racoid process.
From the cartilage of
  the first rib, the in-
  ner and upper part
  of the sternum, and
  a small part of the
  clavicle.
From part of the ba-
  sis and horn of the
  os hyoides.

From  between the
  cartilages  of the
  1st and 2d ribs at
  the upper and in-
  ner  part  of the
  sternum.
From  the  anterior
  part and side of the
  cricoid cartilage.
Into the basis of the
  os hyoides.
Into a rough oblique
  line at the side of
  the thyroid carti-
  lage.
Immediately  under
  the    hyo-thyroi-
  deus.
Into the lower part
  and  inferior  horn
  of the thyroid car-
  tilage.
To draw the os hyoi-
   des downwards.
To raise the thyroid
  cartilage, or de-
  press the os hyoi-
  des.
To pull the thyroid
  cartilage   down-
  wards.
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.
i. Diagiasticus (*.)
3.Stylo-hyoideus(f).
Mylo-hyoideus
(§)  Genohyoide-
us.
Origin,
From a fossa at the
  root of the mastoid
  process, and  like-
  wise  from  the  os
  hyoides.
From the basis of the
  styloid process.

From  the inside  of
  the lower jaw, be-
  tween the last dens
  molaris  and  the
  chin.
From  the inside  of
  the chin.
Insertion,
Into the  lower and
  anterior  part  of
  the chin.
Into the side and fore
  part of the os hy-
  oides near its base.
Into the  basis of the
  os hyoides.
Into the base of the
  os hyoides.
        Use,


To draw the lower
  jaw downwards.
To draw the os hyoi-
   des  obliquely  up
   wards.
To move the os hyoi-
   des to either side,
   forwards  or  up-
   wards.

To move the os hy-
   oides forwards or
   upwards.
o
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6*
  (*\  From S.c v»™ fUveHterJ because it has two fleshy bellies with a*middle tendon.  This tendon passes through the stylo-hyoideus.
  (t'  In some subjects we meet with another muscle, which from its having nearly the same origin, insertion, and use as this, has been

Da7*eds?name°d from iu arising near the dentes molares 0«m.J and its being inserted into the os hyoides.
  (4 i  From y*»"3"> mtntum, the " chin-' 
      Name.

5. Genio glossus.


6. Hyo-glosbUs(*).


7. Lingualis.


8. Stylo-glossus.
6
■tgt
Insertion.
From  •}■■-:  inside of  Into the tongue and
  th-.- cnin.              basis of the os hy-
                        oides.
From  the horn, ba-  Into the tongue late-
  sis,  and appendix     rally.
  of the os hyoides
Laterally  from the  Into the extremity of
  root of the tongue.     the tongue.
9. Stylo-pharyngxus.
From the styl- 'id pro-
  cess,  and  some-
  times also from a
  ligament that  ex-
  tends from'thence
  to the angle of the
  lowr jaw.
From the  basis of the
  styloid  process.
to. Circumflexus-pa-  From near the bony
  lati.                  part of the Eusta-
                       chian  tube,  and
Into the  side of the
  tongue from the
  rout to near its tip.
Into the  side of the
  pharynx and pos-
  terior  part of the
  thyroid cartilage.
Into  the semilunar
  edge ->f the  os pa-
  lati and the velum
        Use.

To move the t^r-cn;*
   in  various  direc-
   tions
To draw the tongue
   downward and in-
   v ards.
To shorten the tongue
   and draw it back-
   wards.
To move  the tongue
   backwards and to
   one side.
To raise the thyroid
   cartilage and pha-
   r\nx, and likewise
   to dilate the latter.
To dilate and draw
   the velum oblique-
   ly downwards.
(*) From *'t*it torhu, and >x«.e«», lingua, " the tongue." 
Name.
Qrigin.
Insertion.
Us,
pendulum
palati
n. Levator palati.
Muscles    situated
  about the  fauces,   i.  Pil-ito-pharyn-
                         gseus.
Into the velum pen-  To pull  the velum
  dulum palati.         backwards.
Into the  upper and
  posterior part of the
  thyroid cartilage.
                                              from the  spinous
                                              process of the  os
                                              sphenoides.
                                            From  the  membra-
                                              nous  part of the
                                              Eustachian   tube,
                                              and  the extremity
                                              of the os petrosum.
                                            From  the lower and
                                              anterior part of the
                                              cartilaginous extre-
                                              mity of the Eusta-
                                              chian tube  f);the
                                              tendinous  expan-
                                              fion of the circum-
                                              flexus palati;  and
                                              the velum pendu-
                                              lum palati near the
                                              ba is and back part
                                              of the uvula.

   (*) This muscle in its course forms a round tendon, which, after crossing ovei a kind of hook formed by the inner  plate of the
pterygoid process of the sphenoid bone, expands into a tendinous membrane.
   i ) Tht two fibres that arise from the  Eustachian tube are described as a distinct muscle by Albinus, under the name of salpingo-
.fbaryngeus. They serve to dilate the mouth »f the tube.
To raise the pharynx
  and thyroid carti-
  lage, or to pull the
  velum  and  uvula
  backwards    and
  downwards. 
Name.                Origin.               Insertion.                Use.
Muscles at the back
  part of the pharynx.
to
2. Constrictor isthmi
  faucium.
3. Azygos uvulae.
 Constrictor  pha-i
ryngis superior.
2. Constrictor pharynx
  gis medius (J).
From near the basis
  of the tongue late-
  rally.

From the end of the
  suture that unites
  the ossa palati.
From  the  cuneiform
  process- of the  oc-
  cipital  bone;   the
  pterygoid  process
  6f the os sphenoi-
  des, and from each
  jaw  near the  last
  dens molaris (f).
From  the  horn  arid
  appendix of the os
To raise  the  tongue
  anddrawthe velum
  towards it  (* )
Into  the velum pen-
   dulum palati, near
   the basis and fore
   part of the uvula.
Into the extremity of  To shorten the uvu-
   the uvula.             la,  and  bring it
                         forwards and  up-
                         wards.

Into  the middle  of  To move the pharynx
   the pharynx.           upwards  and for-
                         wards, and to com-
                         press its upperpart.
Into  the  middle of  To draw the os hyoi-
  the processus cunei-     des and  pharynx
  (*) This muscle, and the palato-pharyngasus, likewise serve to close the passage into the fauces, and to carry the food into the pha-
rynx.
   t  The three  orders of fibres here mentioned, with a few others derived from the tongue, have given occasion to Douglas to de-
scribe them as four distinct muscles, under the names of uphalo-pharyngaus, mylo-pbaryngeus, ptery-pbaryngaus, and glosso-pbaryngaus.
  f\) Douglas makes two muscles of this the hyo-pharyngaus and syndesmo-pharyngaus.
3
 3.
 
Name.
                   j .Constrictor pharyfi-
                      gis inferior (*).
        about  the
glottis  -    -   -  I.  Crico arytacnoide-
                      us lateralis.

                    2.  Crico-arytaenoide-
                      us posticus.

                    3. Arytaenoideus ob-
                      liquis.

                    4. Arytaenoideus
                      transversus.

                    5.   Thyreoarytaenoi-
                      deus.
{•) Th« cri(
      Origin.
  hyoides, and from
  the  ligament that
  unites it with the
  thyroid cartilage.

From the cricoid and
  thyroid  cartilages.

From  the side of the
  cricoid cartilage.

 From the cricoid car-
   tilage posteriorly.

 From the basis of one
   of  the   arytaenoid
   cartilages
 From one of the ary-
   taenoid   cartilages
   laterally.
 From  the  posterior
   and under part of
   the  thyroid carti-
   lage.
iryngxus and thyro-pharyn,
      Insertion.
  formis of the occi-
  pital  bone,  about
  its  middle and be-
  fore the great  fo-
  ramen.
Into  the middle  of
  the pharynx.

Into the basis of the
  arytaenoid    carti-
  lage  laterally.
 lnt  the  basis of he
   arytaenoidcartilage
   posteriorly
 Near the extremity of
   the  other  arytae-
   noid cartilage.
 Into the other arytae-
   n. id cartilage late-
   rally.
 Into  the  arytaenoid
   cartilage.


jseui of Douglas.
     Use.
upwards,  and  to
compress the latter.
To compress part of
   the pharynx.

To open the glottis.


To open the glottis.


To draw the parts it
   is  connected  w ith
   towards each other.
 To shut the glotts.


 To draw the  arytae-
   noid cartilage ror-
   wards. 
Muscles at the fore
   part  of the  neck,
   close to the verte-
   brae
       Name.

(5.  Arytacno-epiglot-
  tideus.

7.  Thyreo-epiglotti-
  deus.
 Rectus capitis in-
ternus major.
2.  Rectus  capitis in-
  ternus minor.
3. Rectus capitis  la
  teralis-.
      Origin.

From the upper part
  of  the  ;rytaenoid
  cart'lage laterally.
Fn-m the thyroid car-
  tilage.
      Insertion.

Into the side of the
  epiglottis.

Into the side of the
  epiglottis.
From the anterior ex-
  tremities  of   the
  transverse  proces-
  ses of the five 1 w-
  ermost cervical ver-
  tebrae.
From  the  anterior
  and upper  p^rt of
  the  first  cervical
  vertebra
From  the  anterior
  and Upper  p rt of
Into the fore  part of
  the cuneiform pro-
  cess of the os occi-
  pitis.


Near the basis of the
  condyloid  process
  of tire os occipitis.

Into  the  os  occipi-
  tis,  opposite to the
        Use.

To move the epiglot-
   tis outwards.

To pull  the epiglot-
   tis obliquely down-
   wards (*.)
To bend  the  head
  forwards.
To assist the last  de-
   scribed muscle.
To move the head to
   one side.
SP-
SS


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(•) When either this ©r the preceding muicle acts with its fellow, the epiglottis is drawn directly downwards up»n the glottu
 
       Name.                Origin.                Insertion.                Use.            £

                         the transverse pro-    stylo mastoid fora-
                         cess of the first cer-    men.
                         vical vertebra.
4, Longus colli.       Within  the  thorax,  In'o the  second  cer-  To pull the neck  to
                         laterally from the^- yicalvertebra ante-     one side (*).
                         bodies of the three    riorly.
                         uppermost  dorsal                                                ^O
                         vertebrae; from the                                                ^
                         basis and fore part                                                *£,
                         of the  transverse                                                ^
                         processesoffhefirst                                                ^
                         and second dorsal                                                ^
                         vertebrae,  and  of                                                co
                         the  last   cervical                                                ^«
                         vertebra; and last-                                                '?
                         ly, from the ante-
                         rior extremities of
                         the transverse pro-
                         cesses of the 6thj
                         5th,  4th,  and  3d
                         cervical vertebrae.
(») When both muscles act, the neck is drawn directly forwards. 
-------at  the fore
 part of  the abdo-
 men   -
Name.
i. Obliquus externus.
2. Obliquus internus.
Qri° m.
From theloweredges
   of the  eight infe-
   rior ribs, near their
   cartilages.
From the spinous pro-
   cess  of  the  three
   lowermost lumbar
   vertebrae, the back
   part of the os sa-
Inscrtion.
Use.
Into  the  linea  alba
  (* ),cssapubis(f),
  and  spine  cf  the
  ilium \x).
                        To compress and fup-
                          port   the  viscera,
                          assistin evacuating
                          the faeces and urine,
                          draw down the ribs,
                          and bend the trunk
                          forwards,  or  ob-
                          liquely to one bide.
Into the cartilages cf  To assist the obliquus
  all the  false  ribs,    externus.
  linea alba (§), and
  fore  part  of  the
  pubis.
  (*) The linea alba is that tendinous expansion which reaches from the cartilago ensiformis to the os pubis.   It is formed by the inter-
lacement of the tendinous fibres of the oblique and transverse muscles, and on this account some anatomists have considered these as
three digastric muscles.
  (t) A little above the pubis the tendinous fibres of this muscle separate from each other, so as to form an opening called the ring of
the obliquus externus, and commonly, though improperly, the ring of the abdominal muscles, there being no such aperture either in the
transversalis or obliquus internus.  This ring in the male subject affords a passage to the  spermatic vessels,  and in the  female to  the
round ligament of the uterus.
  (\) 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  l>y some Fallopius's, and by others Faupart's ligament.  The blood-vessels pass under  it to the thigh.
 ' ($) The tendon formed by the upper part of this muscle in its way to the linea alba is divided into two layers.   The posterior layer
runs ondcr, ;uid the anterior one over, the rectus muscle1. 
Name;
3. Transversalis.
Origin.
Insertion.
Use.
Into  the linea  alba  To compress the ab-
  and cartilago ensi-    dominaLviscera.
  formis.
4. Rectus abdominis.
  crum, the spine of
  the ilium, and back
  part of F-illopius's
  ligament (*).
From  the  cartilages
  of the seven inferi-
  or ribs;  the trans-
  verse  processes of
  the last dorsal, and
  four upper lumbar
  vertebra?; the inner
  part of Fallopius's
  ligament and  the
  spine of the ilium.
From the upper edge  Into the cartilages of  To compress the fore
of the  pubis  and
the symphysis pu-
bis.
part of  the  abdo-
men, and to bend
the trunk forwards.
                                                                       the  5 th,  fith. and
                                                                       7 th   ri s, and  the
                                                                       ed./.e of  the  carti-
                                                                       lago ensiformis(f)
  (*)  From this part it detaches some fibres which extend downwards upon the spermatic chord,  and form what is described as the
cremaster muscle.
   t)  The fibres of the rectus are generally divided by three tendinou. intersections.  The two upper thirds of this muscle passing be-
tween the tendinous layers of the obliquus internus, are inclosed as  it were in a sheath ;  but at its  lower part we find it immediately
contiguous to the peritonasum, the inferior portion of the tendon of the transversalis passing orcr the rectus, and adhering to the anus-
rior layer of the obliquus interna*.
OB
$ 
       Name.

5. Pyramidalis (*).
Must lis at the fore
  part of the thorax.
1. Pectoralis Major.
2. Subclaviust.
      Origin.

From  the  anterior
  and upper part of
  the pubis.
From  the cartilagi-
  nous ends of  the
  5th  and 6th ribs ;
  the  sternum,  and
  anterior part of the
  clavicle.
From  the  cartilage
  of the first rib.
      Insertion.

Into the  linea  alba
  and inner  edge of
  the  rectus,  com-
  monly  about two
  inches  above  die
  pubis.

Into the upper and in-
  ner part of the os
  humeri (f).
Into the under
  face  of  the
  vicle.
sur-
cla-
        Use.

To afflft  the  lower
  portion of the rec-
  tus.
To draw the arm for-
   wards, or oblique-
   ly forwards.
To move  the  clavi-
   cle forwards  arid
   downwards, and to
   as isr in raising the
   first rib.
3
 S-
Co


Co
(•) This muscle is sometimes wanting.                                                 ,
(t) The fibres of this muscle pass towards the axilla in a folding manner, and with those of the latissunus dorsi form the arm-pit.
 
Muscles  that  con-
  cur in forming the
  thorax,
     Name.

 Pectoralis minor
(*).
4. Serratus Magnus.
1. Diaphragma  (f).
2. LeVatores  consta*
   rum.
. Intercostales exter-
 ni,
. Intercostales inter-
 terni (J).
       Origin.

From the upper edges
   of the 3 d, 4th, and
   5 th ribs.

From the eight supe-
   rior ribs.
From the transverse
  processes of the last
  cervical  and  the
  eleven  upper dor-
  sal vertebrae.
From the lower edge
  of each upper rib.
      Insertion.

Intothe coracoid pro-
  cess  of  the  sca-
  pula.

Into the basis of the
  scapula.
         Use.

To move  the scapu-
   la  forwards  and
   downwards,  or to
   elevate the ribs.
To bring the scarula
   forwards.
O
o
Into the upper side of  To move the ribs up-
  each  rib,  near its    wards   and   out-
  tuberosity.            wards.
Into the superioredge  To elevate the ribs.
  of each lower rib.
  (*) This and some other muscles derive their name of serratus, from their arising by a number of tendinous or fleshy digitations, re-
sembling the teeth of a saw  (serra.J
  (t) For a description of the diaphragm, see Part IV. Sect. IV.
  (i) The origin, insertion,  and us* of the internal intercostales, are similar to those of the external.  The reader, however, will b«
pleased to observe, that the ibtercostales 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 interni j and the latter, on the contrary, ess-
tend only from the sternum to the angles of each rifc.
3 
Name.
part
and trunk,
—at the back
of  the  neck
5.Sterno-costales(*).
Trapezius (f), or
cucullaris.
n
       Origin.

From the cartilagoen-
   tiformis, and low-
   er and middle part
   of the sternum.
From the middle of
   the  os  occipitis,
   and the spinous pro
   cesses  cf the  two
   inferior   cervical,
   and of all  the dor-
   sal, vertebrae (%).
       Insertion.

Into the cartilages of
  the   2d,  3d,  4th,
  5th, and 6th ribs.
Into   the  posterior
  half of the clavicle,
  part of  the  acro-
  mion, and the spine
  of the  scapula.
         Use.

To depress the cari^
   lages of the ribs.
To move the scapula.
  The fibres of the external mufrtes run obliquely forwards; thofe of the internal obliquely backwards.  This difference in the direc-
tion of thdr ^        Galen to fuppofe that they  were intended for different ufes ; that the external  intercoftals, for inftance
Tveo elevate and tL internal ones todepress the ribs.  Fallopius seems to have been the first who ^^^^%^
of7his doctrine, which has since been revived by Boyle, and more lately still by Hamberger, whose theoretical arguments on this sub-

^^""ot^^                                    each side.   Vesalius, and after him Douglasand Albiiuis,<:on-
sider them as forming a single muscle, which, on account of its shape, they name triangularu.  Verheyen, Winslow, and Haller, more
^Lr;^. bTthem as so many separate muscles, which, on account of their origin and insertion, they name firno-coftale,.
P  (Pt  Inamedi oyRioLnurfron, ?,«*, on account of its quadrilateral fliape.  Columbus and others gave it the name of Allans,

^^^^Si^^W, united with thofe of its fellow in the aapc of the neck, form what is  called  the ligament 
Name.
z. Rhomboideus (*).
3. Latissimus dorsi.
4. Serratus
  posticus.
inferior
       Origin.

From the fpinous pro-
  ceffes of the three
  lowermoftcervical,
  and of all the dor-
  fal vertebras.
From  part  of  the
  spine of the os ili-
  um,  the   spinous
  processes of the os
  sacrum and lumbar
  vertebrae, and of six
  or eight of the dor-
  sal  vertebrae; also
  from the four infe*
  rior false ribs neap
  their cartilages.
From the spinous pro-
  cesses of the two
  lowermost  dorsal,
  and of three of the
  lumbar vertebras.
      Insertion.

Into the basis of the
  scapula..
Into the os humeri,
  at the inner edge
  of the groove  for
  lodging  the long
  head of the biceps
  muscle.
Into the lower edges
  of the three or four
  lowermostribsnear
  their cartilages.
        Use.

To move the scapula
  upwards and back-
  wards.
To draw the  os hu-
   meri  downwards
   and backwar ds,and
   to roll  it upon its
   axis.
to
O
to
To draw the ribs out-
  wards,downwards,
  and backwards.
e*
Co
  (*) This muscle consists of two distinct portions, which are described as separate muscksby Albinus, under the names of rbomboMcus
minor and rhomboideus my or. 
       Name,

5. Levator scapulae.
6. Serratus superior
  posticus.
7. Splenius (*);
      Origin.

From the transverse
  processes  of  the
  four    uppermost
  vertebrae colli.
From the lower part
  of the ligamentum
  colli,  the  spinous
  process of the low-
  ermost    cervical
  vertebra,  and  of
  the   two  superior
  dorfal vertebras.
 From  the  spinous
  processes   of the
  four or five upper-
   most vertebrae of
   the back,  and of
   the lowermost cer-
   vical vertebral
Insertion.
Use.
Into the upper angle  To move the scapula
  of the scapula.        forwards  and up-
                        wards.

Into the 2d,  3d, and  To  expand  the tho-
  4th ribs.              rax.
Into  the transverse
  processes   of  the
  two first  cervical
  vertebrx,  the  up-
  per and back part
  of the mastoid pro-
  cess, and a ridge
  on the os occipitis.
To move  the
  backwards.
head
a-
Co


Co
  (*) According to some writers, this muscle has gotten its name from itsmemblanee to the spleen; others derive it hcmjpimum
•jplint.
o
C/J 
Name.                 Origin.             Insertion,                 Use.
8. Complexus (*).
9.  Trachelo-mastoi-
  deus (f).
10. Rectus capitis po-
  fticus major.

11 •  Rectus capitis po-
  sticus minor.
12. Obliquus superior
  capitis.
 From the transverse
   processes of thefour
   or five  uppermost
   dorsal,  and of the
   six lowermost cer-
   vical vertebrae.

 From the transverse
   processes of the first
   dorsal    vertehra,
   and four or  five of
   the lowermost, cer-
   vical vertebrae.
 From thespinouspro-
   cess of  the second
  cervical vertebra.
From the  first verte-
  bra of the neck.
From the  transverse
  process Of the first
  cervical  vertebra.
 Into the os occipitis






 Into the mastoid pro-
   cess.




 Into the os occipitis.


Into the os occipitis.

Into the os occipitis.
To draw  the head
  backwards.
To draw  the head
  ba<-kwa;ds.
To extend the head
   and draw it back-
   wards.
To assist  the  rectus
   major.
To draw  the  head.
   backwards.
(•> So named on account of its complicated stricture.
(f) So named from its origin from the neck (Tp»<ajii».ois) and its insertion into the mastoid process. 
Name.
Origin.
Insertion.                 Use.
J3. Obliquus inferior
  capitis.
14.   Sacro.lumbalis
15. Longissimus dor-
  si (tj.
From the spinous pro-
   cess of the  second
   cervical vertebra.
From  the back part
  of the os  sacrum,
  spine of the  ilium,
  spinous  processes
  and  roots  of the
  transverse  proces-
  ses of the vertebrae
  of the loins.
The same as that of
  the sacro-lumbalis.
Into  the  transverse
  process of the frst
  cervical vertebra.
Into the  lower  edge
  of each rib.
Into  the  transverse
processes
f  the
dorsal vertebrae.
To draw the face to-
   wards  the  shoul-
   der,  and to move
   the  first  vertebra
   upon the second.
To  draw  the   ribs
   down-vards, move
   the  boly upon  its
   axis, assist in erect-
   ing  the trunk, and
   turn the neck back
   wards,  or  to one
   side.
To stretch  the verte-
   brae  ot  the  back,
   and keep the  ti unit
   erect.

   (•) Several thin fasciculi of fleshy fibres arise from the lower ribs, and terminate in the inner side of this muscle. Steno namc3 them
musculi ad sacro-lumbalem accejforii.  The sacro-lumO.., s likewise sends off a fleshy s'ip from its upper part, which by Douglas and Albinus
is describe  as a distinct muscle, under the name of urvicalis descendens. Morgc-c:  has very properly considered it as a part of the sacro-
lumbalis-                                                                                              .     , .
    f  At the  u per part of this muscle a broad thin L>yer of fleshy fibres  is found crowng, and intimately adhering to it.  This portion,
which is descrih:'■' by Albinus, under the name of transversalis .ervtcis,  m. )  \  ) pr« :  ' .y be considered as an appendage to the long.'ssi
mus dorsi.  It arises from the transverse processes of the five or six superior dorsal  verteur^, and is inserted into the transverse processes of
O 
        Name,

16. Spinalis dorsi.
17. Semi-fpinalis dor-
  si.
18.  Multifidus  Spi-
  nae (*).
       Origin.

From  the   spinous
  processes of the up-
  permost   lumbar
  and     lowermost
  dorsal vertebrae.
From the transverse
  processes  of  the
  7th,  8th, 9th, and
  ioth  vertebrae  of
  the back.

From the os sacrum,
  ilium,  oblique and
  transverse proces-
  ses of the lumbar
  vertebrae,    trans-
  verse processes of
Insertion.	Use.	to o
Into the spinous pro-	To extend the verte-	
cesses of the nine	bra;.	
superiordorsal ver-		
tebrae.		
Into the spinous pro-	To extend the fpine	
cesses of the four	obliquely back-	
uppermost dorsal,	wards.	Ǥ
and lowermost of		
the cervical verte-		<*». &-
brae.		rt>
Into the spinous pro-	To extend the back	b*
cesses of the lum-	and draw it back-	gt
bar, dorsal, and six	wards, or to one	5
of the cervical ver-	side.	
tebrae.		Co
the six inferior cervical vertebrae.  By means of this appendage the longissimus dorsi may serve to move the neck to one side, or oblique-
ly backwards.
    *) Anatomists in general have unnecessarily multiplied the muscles of the spine.  Albinus has the merit of having introduced greater
simplicity into this part of myology.  Under the name of multifidus spina, he has very properly included those portions of muscular flesh
intermixed with tendinous fibres, situated close to the back part of th* spine, and which are described by Douglas under the names of
transversales colli, dorsi, \Sf lumborum. 
Name.
Origin.
Insertion.
Use.
lo. Semi-spinalis col-
  li.
20. Scalenus  (*).
21. Inter-spinalis (f ).
  the   dorsal,  and
  four of the cervical
  vertebrae.
From the transverse
  processes of the five
  or six  uppermost
  dorsal vertebrae.

From  the  transverse
  processes  of  the
  five inferior  cervi-
  cal vertebrae.
From the  upper part
  of each of the fpi-
  nous processes  of
  the six inferior cer-
  vical vertebrae.
Into the spinous pro-
  cesses  of the  2d,
  3d,  4th, 5th,  and
  6th   cervical  ver-
  tebras.
Into  the upper  and
  outer part of  the
  first   and  second
  ribs.
Into the under part of
  each of the spinous
  processes   of  the
  vertebrae above.
To stretch the  neck
  obliquely    back-
  wards.
To  move  the  neck
  forwards, or to one
  side.

To draw the spinous
  processes towards
  each other.
3
 «*•.
 »-
  (*) The ancients gave it this name from its resemblance to an irregular triangle (<m«M'«s).  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 ex-
tremities  The middle is in part covered by the posterior portion, which is the longest and thinnest of the three.
   f) In the generality of anatomical books we find these muscles divided into inter-spinalis cervicis, dorsi, and lumberttm, but WC do not find
any such muscles either in.the loins or back.          '
to
o 
$
Muscles within the
  cavity of the abdo-
  men,,  on the ante-
  rior   and  h'ltcr.;]
  parts  of the spine,
       Name.

22. Inter-transversa-
  les (*).
i. Psoas parvus (f).
3. Psoas magnus.
       Origin.

From the upper part
   of each of the trans-
   verse  processes  of
   the vertebrae.
From  the sides  and
  transverse  proces-
  ses  of the upper-
  most lumbar verte-
  bra, and sometimes
  of  the lowermost
  dorsal vertebra.
From the bodies and
  transverse  proces-
  ses of the  last  dor-
  sal,   and   all the
  lumbar vertebrae.
Insertion.
Use,
Into the under part of To  draw the trans-
  each of the trans-    verse processes to-
  verse processes  of    wards each other.
  the vertebras above.
Into the brim  of the
  pelvis, at the junc-
  tion of the os pubis
  with the ilium.
Into the os femoris, a
  little below the tro-
  chanter minor.
To bend the loins for-
   wards.
To bend  the
   lorwards.
thigh
  (*> These muscles are to be found only in the neck and loins ; which have been described, as the inter-trans-vir sales dorsi being rather

^VThtTnd^herilowing pair of muscle, derive their name of psoa, from*-, lumbus, on account of their situation at the anterior part-
of the loins. 
Name.
&rigin.
u
3. Iliacus internus.    From  the  inner  lip,
                        hollow  part,  and
                        edge  of  the  os
                        ilium.
4. Quadratus lumbo-  From  the  posterior
   rum  (*).             part of the spine
                        of the ilium.
5. Coccygseus.
From  the  posterior
  and inner edge of
  the  spine of  the
  ischium.
      Insertion.

In common with the
  psoas magnus.


Into  the   transverse
  processes  of  the
  four    uppermost
  lumbar   vertebrae,
  the  inferior  edge
  of the last rib, and
  the side of the low-
  ermost dorsal  ver-
  tebra.
Into  the lower  part
  of the os sacrum,
  and  almost  the
  whole length of the
  os coccygis  late-
  rally.
         Use,

To assist  the psoas
   magnus.
To support the spine,
  or to draw it to one
  side.
To draw  the os coc-
   cygis forwards and
   inwards (f).

  (*) So called from its shape, which is that of an irregular square.                        ....   ,1     _._» Ar .t,.
  (V Some of the fibres of this muscle ace united with those of the levator ani, fo that it assists in closing the lower part ot we
pelvis.
to
o 
n  ..on the scapu-
 la and tipper part
 of the osJiumeri,
Name.
i. Deltoidcs (*).
2, Supra-spinatus..


3. lnfra-spinatus.


4. Teres minor (f).

5, Teres major.
6. Subscapularis.
Origin.
From   the  clavicle,
  processus  acromi-
  on,  and  spine of
  the scapula.
From the basis, spine,
  and upper costa of
  the scapula.
From  the  base  and
  spine of the scapu-
  la.
From the inferior co-
  sta of the scapula.
From   the   inferior
  angle, and inferior
  costa of the scapu-
  la.

From the basis, supe*
  rior and inferior co-
  sta of the scapula*
Insertion.
Into the anterior and
   middle part of the
   os humeri.

Into a large tubero-
   sity at the head of
   the os humeri.
Into the  upper and
   middle part of the
   tuberosity.
Into the lower part of
   the tuberosity.
Into the ridge at the
   inner  side of the
   groove formed for
   the long head of
   the biceps.
Into the upper part of
   a small  tuberosity
   at the  head of the
   os humeri.
Use.
To raise the arm-
To raise the arm.
To roll the os humeri
   outwards.

To assist  the  infra
   spinatus.
To assist in the rota-
   tory motion of the
   arm.
To roll the  arm in-
  wards.
-(*) Sto named from its supposed resemblance to the Greek a reversed.
l.\ ) This and the following pair are called tores, from their being; of a long and round shape. 
Muscles on the os
  humeri,  -   -   -
   Name,

 Coraco-brachia-
lis (*).
r. Biceps flexor cubi-
  ti.
     Insertion.

Into the middle and
  inner side of  the
  os humeri.

Into the tuberosity at
  the upper end  of
  the radius.
                 Origin.

             From   the  coracoid
                process of the sca-
                pula.

             By two heads, one
                from the coracoid
                process,  and  the
                other, or long head,
                from the upper and
                outer edge of the
                glenoid  cavity  of
                the scapula.
             From the os humerij
                below, and at each
                side  of the tendon
                of the deltoides.
             By three  heads; the
                first, from the infe-
                rior  costa  of the
                scapula;  the  se-
                cond, from the up*-
                per and outer part

(*) This mustle affords a passage to the mttsculo-cutaneiBui nerve.
        Use.

To roll the arm for-
  wards and upwards.
Tobend the fore-arm.
* Brachialis internus.
 Triceps  extensor
cubiti.
Into a small tubero-
  sity at the fore part
  of the coronoid pro-
  cess of the ulna.
Into  the upper and
  outer part of the
  olecranon.
To assist  in bending
  U\e fore-arm.
To extend the fore-
  arm.
fc> 
Name.
on  the  fore-
arm,     -     -    i. Supinator longus.
2. Extensor carpi ra-
  dialis longus.
3. Extensor carpi ra-
  dialis brevis.
4. Extensor  digito
  rum communis.
         Origin.

  of the os  humeri;
  and the third, from
  the back  part  of
  that bone.

From the outer ridge
  and anterior sur-
  face of the  os hu-
  meri, a little above
  its outer condyle.
Immediately  below
  the  origin  of the
  supinator longus.

From the outer and
  lower part  of the
  outer  condyle  of
  the os humeri, and
  the upper part  of
  the radius.
From the  outer con-
  dyle of the os hu-
  meri.
Insertion.
Use,
to
13
Into the  radius near
  its styloid process.
Into the upper  part
  of the metacarpal
  bone  of the fore-
  finger.
Into the upper part
  of the metacarpal
  bone of the middle
  finger.
To assist  in  turning
  the palm  <^f  the
  hand  upwards.
To extend the wrist.
To assist the extensor
  longus.
Into the back part of To extend the fingers
  all the '^ones of the
  fore finger.
•3 
Name.                 Origin.                Insertion.                Use.
nans.
7. Anconaeus (*).
5. Extensor  minimi  From the outer con.
  digiti.                 dyle of the os hu-
                         meri.
6. Extensor carpi ul-  From the outer con-
                         dyle of the os hu-
                         meri.
                       From the outer con-
                         dyle of the os hu-
                         meri.
8. Flexor carpi ulna-  From the  inner con-
   ris.                   dyle of the os hu-
                         meri, and a .terior
                         edge of the olecra-
                         non (f).
                       From the inner con-
                          dyle of the os  hu-
                          meri.
9. Palmaris longus.
Into the b^nes of the  To ext nd the  little
  little finger.           finger.

Into the  metacarpal  To assist in extending
  bone of  the little     the wrist.
  finger.
Into the  outer edge  To  extend  the  fore
  of the ulna.           arm.

Into the os pisiforme.  To assist in bending
                         the hand.
Into the internall an-  To bend the hand.
  nular   ligament,
  and   aponeurosis
  p ilmaris \%).
3
a*
  (*) So called from »y«»v, cubitus.
  (+) Betwe n t te two origins of this muscle we find the ulrtor-nerve going to the fore arm.
  , i  The a  oneurosis palm .ris is a tendinous membrane that , xtoids  over the palm of the hand.  Some  anatomists have supposed it
to be a production of the tendo,, of this iruscle, but without sufii --M grounds; for in seme subjects we find  the palmaris longus inserted
whoiiy -.to the annular lij/animt, sr is ^o be perfectly distinct from this aponeurosis; and it now and then happens, that no palmaris
longus u to be found,  whertas this expansion is never deficient.
03 
       Nam*.

yOt Flexor £arpi ra,
  dialis.

11.  Pronator  radii
  teres.
12. Flexor  sublimis
  perforatus (*).
13. Supinator  radii
  brevis.
       Origin.

From the inner con-
  dyle of the  os hu-
  meri.
From the outer con-
  dyle of the os hu-
  meri, and coronoid
  process of the ulna.
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.
From the outer con-
  dyle of the os hu-
  meri, and posterior
  surface and outer
  edge of the ulna.
       Insertion.

Into the metacarpal
  bone of  the fore
  finger.
Into the anterior and
  convex edge  of the
  radius   near  its
  middle.
Into the second bone
  pf each finger.
Into the anterior, in-
  ner, and upper part
  of the radius.
        Use.           &

To bend the hand.
To roll the  hand in-
  wards.


To bend the  second   Qr
  joint of the finger.
To roll  thp  radius
  outwards.
I
  (•) This muscle is named perforator, en account of the four tendons in which it terminates, being perforated bf those of another
muscle, the perferans. 
       Name.

14. Abductor
  cis longus.
15.  Extenfor
  pollicis.
16.  Extensor
  pollicis.

17.  Indicator.
0i
tgt
polli-  From the middle and
         back  part of the
         ulna,  interofleous
         ligament, and ra-
         dius.
minor  From the back  part
         of the ulna, and in-
         terofleous li gament
         and radius.
major  From the back of the
         ulna and interofTe-
         ous ligament.
       From  the middle  of
         the ulna.
18. Flexor profundus
  perforans.
19.   Fleicor
  pollicis*
longus
From the upper and
  fore  part  of the
  ulna, and interos-
  seous ligament.
From the upper and
  fore part  of the
  radius*
      Insertion.

By two tendons into
  the os trapezium,
  and first  bone of
  the thumb.

Into the convex part
  of the second bone
  of the thumb.

Into  the  third  and
  last bone of the
  thumb.
Into  the metacarpal
  bone of the  fore-
  finger.
Into  the fore part of
   the last  bone of
   each of the fingers.
       Use.

To stretch the  first
  bone of the thumb
  outwards.
To extend the second
  bone of the thumb
  obliquely     out-
  wards.
To stretch the thumb
  obliquely    back-
  wards.
To extend the fore-
   finger.

To bend the last joint
   of the fingers.
Into the last joint of  To bend the last joint
  the thumb.           of the.thumb..
a-
c-r

60
to
09 
       Name,

20.  Pronator
  quadratus.
             Origin,

radii  From  the  inner and
         lower part of the
         ulna.
      Insertion.

Into the radius, op-
  posite to its origin.
MuscLEsonthehand,  1. Lumbricales (*).   From the tendons of Into  the  tendons of
                                              the perforans.
2. Abductor  bravis  From the  fore  part
  pollicis.               of the intern d an-
                        nular ligament, os
                        scaphoides, and one
                        of the tendons of
                        the abductor  lon-
                        gus pollicis.
3. Opponens pollicis.  From the inner and
                        antei ior part of the
                        internal annular li-
                        gament,  and from
                        the os scaphoides.
the extensor  digi-
torum communis.
Into the outer side of
  the 2d bone of the
  thumb,  near  its
  root.
        Use.

To roll the radius in-
   wards,     nd   of
   course to assist in
   the  pronation  of
   the hand.
To bend the first, and
   to exiend  the  two
   last  joints of  the
   fingers (f).
To move the thumb
  from the lingers.
Into the first bone of  To move the thumb
  the thumb.           inwards,  and  to
                        turn it upon  its
                        axis.
   (") So named from their being shaped somewhat like the lumbricus or earth-worm.
   (■|-  Fallopius whs the first who remarked the two opposite uses of this muscle.  Their extending power is owing to their connection
with the extensor communis.
to
«S 
Name.
Origin.
Insertion.
Use.
rt
4. Flexor brevis  pol*
  licis.
5. Abductor pollicis.


6. Abductor indices.




7. Palmaris brevis.
8. Abductor  minimi
  digiti.

9. Flexor parvus mi-
  nimi digiti.
From the os trapezdi-
  des, internal annu-
  lar  ligament,  os
  magnum, and os
  unciforme
From the metacarpal
  bone of the middle
  finger.
From  the inner side
  of the first bone of
  the  thumb,   and
  from the os  trape-
  zium.
From the internal an-
  nular ligament, and
  aponeurosis    pal-
  maris.
From the internal an-
  nular ligament and
  os pisiforme.
From the os uncifor-
  me and internal an-
  nular ligament.
Into the  ossa  sesa-
  moidea and second
  bone of the thumb.
Into the basis of the
  second bone of the
  thumb.
Into the first  bone of
  the fore finger pos-
  teriorly.
Into the os pisiforme,
  and the skin cover-
  ing  the abductor
  minimi digiti.
Into the  side  of the
  first bone  of the
  little finger.
Into the first bone of
  the little finger.
To bend the second
  joint of the thumb.
To move the thumb
   towards  the  fin-
   gers.
To move the fore fin-
   ger  towards  the
   thumb.
To contract the palm
  of the hand.
To draw  the little
   finger  from   the
   rest.
To bend the little fin-
  ger.
$

fcO 
Name.
Origin.
Insertion.
Use.
Muscles at the back
  part of the  pelvis,
  and upper part of
  the thigh,   -
10. Abductor meta-
  carpi minimi digiti.

n. Interossei interni.
i2.Interossei externi.
i. Glutaeus (f) max-
  imus.
From the os uncifor-
  me and internal an-
  nular ligament.
Situated, between the
  metacarpal bones.
Situated between the
  metacarpal  bones
  on the back of the
  hand.
From the spine of the
  ilium, posterior sa-
  cro-ischiatic  liga-
Into the metacarpal
  bone  of the little
  finger.
Into the roots of the
  fingers.


Into the roots of the
  fingers.
To move that bone
  towards the rest.

To extend the fingers
  and move them to-
  wards  the  thumb

To extend  the  fin-
  gers ;  but the  first
  draws  the  middle
  finger inwards, the
  second draws it out-
  wards,  and  the
  third draws thering
   finger inwards.
Into the upper part  To extend the thigh
  of the linea as per a    and  draw  it  out-
  of the os femoxis.      wards.
  (*) The third interosseus internus (for there are four of the externi and three cf the interni) differs from the rest in drawing the
middle finger from the thumb.
  (f) From >-».»">, nates. 
Name.
Origin.
Insertion.
Use.
2. Glutaeus medius.
3. Glutaeus minimus.
4. Pyriformis (*).
5. Gemini  (f).
  ments,  os sacrum,
  and os  coccygis.
From  the spine  and
  superior surface of
  the ilium.
From the outer  sur-
  face of the  ilium
  and the border of
  its great niche.
From  the   anterior
  part of the os sa-
  crum.
By  two portions, one
  from the outer sur-
  face of  the spine
  of  the   ischium;
  the other  from the
Into  the  outer  and
  back part  of the
  great trochanter of
  the os femoris.

Into  the  upper  and
  anterior part of the
  great trochanter.

Into a cavity at the
  root  of  the  tro-
  chanter major.
Into the  same cavity
  as the pyriformis.
To draw  the  thigh
  outwards and a lit-
  tle backwards, and
  when it is bended,
  to roll it.
To assist the former.
To roll the thigh out-
  wards.

To roll the thigh out-
  wards, and likewise
  to confine the ten-
  don of the obtura-
  tor internus, when

  (*) So named from its pear-like shape.
  (t) The two portions of this muscle having been described as two distinct muscles by some anatomists, have occasioned it to be named
gimini.  The tendon of the obturator internus runs between these two portions.
r-* 
Name.
on  the   thigh
(t).
6. Obturator internus.
7. Quadratus (*) fe-
   moris.
1. Biceps  flexor cm-
       Origin,

  tuberosity  of  the
  ischium and poste-
  rior sacro-ischiatic
  ligament.
From   the  superior
  half of  the  inner
  border of  the fo-
  ramen thyroideum.
From the  tuberosity
  of the ischium.
By two heads; one
  from the tuberosity
  of   the   ischium,
Insertion.	Use. the latter is in ac-tion.	to O
Into the same cavity with the former.	To roll the thigh out-wards.	
Into a ridge between the trochanter ma-jor and trochanter	To move the thigh outwards.	Co <■> e\* 06
minor. Into the upper, and	To bend the leg.	
back part of the fi-
bula (t).
  f*\ This muscle is not of the square shape its name would seem to indicate.         ..,.,.         1  i.   •   u
  r+ The muscles of the lee and thigh are covered by a broad tendinous membrane called fasaa lata  that surrounds them in the man-
ner of a sheath.   It is sent off from the tendons of the glut*, and other muscles, and dipping down between the muscles it covers ad-
here, to the linea aspera, and spreading over the joint of the knee,  gradually ^appears on the leg.  It M thickest on the inside of the
thigh.                                          .
  {\) The tendon »f this muscle forms the outer hamstring. 
Name.
Origin.
Insertion,
Use.
2. Semitendinosus.
3.  Semi-membrano-
  sus (*).

4. Tensor vaginae fe-
  moris.
5. Sartorius.
6. Rectus.
   the other from the
   linea  aspera near
   the insertion of the
   glutaeus maximus.
From  the tuberosity
   of the ischium.

From  the tuberosity
   of the ischium.

From   the  superior
   and  anterior spi-
   nous process of the
   ilium
From  the  superior
   and anterior spi-
   nous process of the
   ilium.
By two tendons ; one
   from the anterior
   and  inferior spi-
Into  the  upper  and
  inner  part of the
  tibia.
Into  the  upper  and
  back part of  the
  •head of the tibia.
Into the inner side of
  the  fascia   lata,
  which  covers  the
  outside of thethigh.
Into the upper and in-  To bend  the leg in-
  ner part of the ti-    wards (f).
  bia.
To bend and draw the
  leg inwards.

To bend the leg.
To stretch the fascia.
Into the  upper and
  fore-part of the pa-
  tella.
To extend the leg.
s.
CO

?5
(•) So named on account of its origin, which is by a broad flat tendon three inches long.
(t) Spigelius was the firft who gave this the name of sartorius, or the taylor'e muscle, from, its use in crossing the legs,
N3
b3 
Name.
Origin.
Insertion.
Use.
7. Gracilis.


8. Vastus   externus
   (*)•



9. Vastus internus.
  nous process of the
  ilium ;  the  other
  from the posterior
  edge  of the coty-
  loid cavity.
From  the  fore-part
  of the ischium and
  pubis.
From the anterior and
  lower part  of the
  great   trochanter,
  and the outer edge
  of the linea aspera.
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 in-
  ner part of the ti-
  bia.
To the upper and out-
  er part  of the pa-
  tella.
Into  the  upper  and
  inner part of the
  patella.
To bend the leg.


To extend \h.z leg.




To extend the leg.
  (*) The vastus externus, vastus internus, and crurseus, are so intimately connected with each other, that some anatomists have been in
iuced to consider them as a triceps, or single muscle with three heads. 
        Name.

10. Cruraeus (*).


11. Pectinalis.
12. Abductor longus
  femoris (f).

13. Abductor brevis
  femoris.

14- Abductor mag-
  nus femoris.
       Origin.

From the  outer .and
  anterior part of the
  lesser trochanter.
From  the  anterior
  edge of the os pu-
  bis, or pectinis,  as
  it  is   sometimes
  called.
From the upper and
  fore part of the  os
  pubis.
From the  fore  part
  of the ramus of the
  os pubis.
From the  lower and
  fore part of the ra-
  mus of the os pu-
  bis.
Insertion.
Use.
Into the  upper part  To extend the leg.
  of the patella.

Into  the upper and  To  draw the  thigh
  fore part of the li-     inwards, upwards,
  nea aspera.            and to roll it a lit-
                         tle outwards.

Near  the  middle and"
  back part of the li-
  nea aspera.
Into  the inner  and
  upper  part of the
  linea aspera.
Into the whole length
  of the linea aspera.
 To  draw  the thigh
    inwards, upwards,
I"   and to roll it a lit-
    tle outwards.
   (*) Under the crursus we sometimes meet with two small muscles, to which Albinus has given the name of sub-erartti.  They ter-
minate on each side of the patella, and prevent the capsular ligament from being pinched.  When they are  wanting, which is very often
the case, some of the fibres of the crnrsus are found adhering to the capsula,
  (f) 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. 
Musclbs on the leg,
       Nam*,

ij. Obturator exter-
  nus,
i.Gastrocnemius (*)
  externus.
2. Gastrocnemius (f)
  internus.
       Origin.

From part of the ob-
  turator  ligament,
  and the inner half
  of  the  circumfe-
  rence  of the fora-
  men thyroideum.
By two  heads ;  one
  from the inner con-
  dyle,  the   other
  from the outer con-
  dyle of  the  os fe-
  moris.
By two heads;  one
  from the back part
  of the head of the
  fibula, the  other
  from the upper and
  back  part  of the
   tibia.
      Insertion.

Into the os  femoris
  near  the   root  of
  the great  trochan-
  ter.
By a great round •■en-
  don,  common  to
  this and the follow-
  ing muscle.
By a  large tendon
   (the tendo achillis)
   common to this and
   the former muscle,
   into  the lower and
   back part of the os
   calcis.
        Use,

To move the  thigh
  outwards in an ob-
  lique direction,and
  likewise  to  bend
  and  draw  it  in-
  wards.
To extend the foot.
To extend the foot.
to
5s-
Co
(*) r*rpo*»>tjui'*, sura, " the calf of the leg."
(|) This muscle is by some anatomists named soltus, on account of its being shaped like the sole-fish. 
m
**
       Name.

3. Plantaris (*)■
4. Popliteus (\),
5. Flexor longus digi-
  torum pedis {%).
        Origin.

From the upper and
  posterior  part  of
  the  outer condyle
  of the os femoris.
From the  outer con-
  dyle  of the thigh*

From the  upper and
  inner part  of the
  tibia.
       Insertion.

Into the inside of the
  back part of the os
  calcis;
the  upper  and
   part  of the
Into
  inner
  tibia.
By  four    tendons,
  which,  after  pas-
  sing  through  the
  perforations     in
  those of the flexor
  digitorum  brevis,
  are  inserted  into
  the last bone of all
  the toes except the
  great toet
         Use.

To assist  in  extend-
   ing the  foot.
To assist in bending
   the leg and rolling
   it inwards.
To bend the last joint
   of the toe.

R
Co
<->
  (») this muscle has gotten the dame of plantaris, from its feeing 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.
  (+) So called on account of its situation at the ham (poples).                              t                          .
  (|) This muscle, about the middle of the foot, Unites with a fleshy mass, which, from its having first been described by Sylvius, is
fsually called massa ta'rnea JacoBX Sylvii.
to
to 
Name.
6. Flexor longus pol-
  licis pedis.


7. Tibialis posticus.
8. Peroneus longus.
9. Peroneus brevis.
Origin.
Insertion.
Use.
From the back part,
  and a little below
  the head of the fi-
  bula.
From the back part
  and outer edge of
  the tihia, and like-
  wise from  the in-
  terosseous    liga-
  ment and adjacent
  part of the  fibula.
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.
 From the outer and
  fore part of the fi-
  bula.
Into the last bone of To  bend  tire great
  the great toe.          toe.
Into the  inner  and
  upper part of the
  os naviculare and
  side  of the os cu-
  neiforme medium.
To move the foot in-
   wards.
Into the  metatarsal  To move the foot out-
  bone  of the  great     wards.
  toe.
Into the  metatarsal
  bone  of the little
  toe.
To assist the last de-
   scribed  muScle.. 
Name.
10.  Extensor longus-
  digitorum pedis.
n. Peroneus tertius.
12. Tibialis antrcas.
                     13. Extensorproprius
                       pollicis pedis.

Muscles onthefootr 1. Extensor brevis di-
                       gitorum pedis.
Origin.
Insertion.
Use.
From the upper, out-
  er, and  fore  part
  of the tibia, inter-
  osseous  ligament,
  and inner edge of
  the fibula.
From  the  fore-part
  of the lower  half
  of the fibula,  and
  from the  interos-
  seous ligament.
From the  upper and
  fore part of the  ti-
  bia.
From  the upper and
  fore part of the ti-
  bia.
From  the  upper and
  anterior part of the
  os calcis.
By four tendons into
  the first joint of the
   smaller toes.
Into the  metatarsal
  bone  of the little
  toe.
Into  the  os  cunei-
  forme internum.

Into the convex sur-
  face of the bones of
  the great toe.
By four tendons ; one
  of which joins the
  tendon  of  the ex-
  ternus longus polli-
  cis, and the  other
  three the  tendons
  of the extensor di-
  gitorum longus.
To extend the toes.





To ihe bend the foot.




To bend the foot.


To extend  the  great
   toe.

To extend  the toes. 
Name.
Origin,
Insertion.
Use.
to
to
00
t. Flexor brevis d»gi-
  torum pedis.
3. Abductor pollicis
  pedis.

4. Abductor minimi
  digiti,
5, Lumbricales pedis.
From the lower part
  of the os calcis.
From  the inner and
  lower part of the
  os calcis.
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.
From the tendons of
  the  flexor longus
  digitorum pedis.
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.
Into the first joint of
   the great toe.

Into the outer side
   of the first joint of
   the little toe.
Into the tendinous ex-
  pansion at the up-
  per part of the toes.
To bend the second
  joint of the toes.
To move  the  great
  toe from the other
  toes.
To draw the little toe
  outwards.
To draw the toes iar
  wards.

09 
Name.               Origin.               Insertion.
6. Flexor brevis pol-
  licis pedis.
7.  Abductor  pollicis
  pedis.
3. Transversalis  pe-
  dis.
9. Flexor brevis mi-
  nimi digiti pedis.

10.  Interossei  pedis
  interni (*).
.--------■------exter-
  ni (f).
From the inferior and
  anterior part of the
  os calcis, and also
  from  the  inferior
  part of the os  ca-
  neiformeexternum.
From near the  roots
  of  the metatarsal
  bones   of  the  2d,
  3d, and 4th toes.
From the outer and
  under  part of the
  anterior end of the
  metatarsal bone of
  the little toe.
From the basis of the
  metatarsal bone of
  the little toe.
Situated between the
  metatarsal bones.
By two tendons  into
  the  first joint  of
  the great toe.
Into the outer os se-
  samoideum, orfirst
  joint of the great
  toe.
Into the  inner os se-
  samoideum,   and
  anterior end of the
  metatarsal bone of
  the great toe.
Into the first joint of
  the little toe.
To bend the first joint
   of the great toe.
To draw the great toe
   nearer  to the rest,
   and a1 so tobend it.

To contract the foot.
To bend  the  little
   toe.
   (*) The intercssei'interni are three in number; their use is to draw the smaller
   ft) The interossei externi are four in number j the first serves to move the fore
wards.  All the interossei assist in extending the toes.
toes towards the great toe.
toe towards the great toe; the rest move the toes out- 
230
Of the Muscles.
EXPLANATION  of PLATES XXIII. and
                   XXIV.


             Plate  XXIII.


  Fig.  l. 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,  Attol-
lens aurem.  D,  The ear.   E, Anterior  au-
ris.  F F,  Orbicularis palpebrarum.  G, Le-
vator labii superioris alaeque  nasi.  H,  Leva-
tor  anguli oris.  I, Zygomaticus minor.  K,
Zygomaticus  major.  L, Masseter.   M, Or-
bicularis oris.   N,  Depressor labii inferioris.
O,  Depressor  anguli  oris.   P,  Buccinator.
QQ,, Platysma myoides.  RR, Sterno-cleido-
mastoidaeus.   S,  Part  of  the trapezius.  T,
Part of the scaleni.
  Superior Extremity—U, Deltoides. V,
Pectoralis'major-   W, Part of the  latissimus
dorsi.   X X,  Biceps flexor cubiti.  Y Y, Part
of the brachialis externus.   Z Z,  The begin-
ning of the tendinous aponeurosis (from the
biceps), which is spread over the muscles of 
 
r*
if- 
Of the Muscles.          231
 the fore-arm.  a a, Its strong tendon inserted
 into the tubercle of the radius,   b b, Part of
 the  brachialis internus-  c,  Pronator radii te-
 res,  d, Flexor carpi 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,  Abductor pol-
 licis.  1,  Flexor pollicis longus.  m m, The
 tendons of  the flexor  sublimis perforatus,
 profundus perforans,   and lumbricales—The
 sheaths are  entire  in  the right hand,—in the
 left  cut open to show  the tendons  of the flex-
 or profundus perforating the sublimis.
   Muscles  not referred to—in  the left supe-
 rior extremity—n, Pectoralis minor,  seu ser-
 ratus  anticus minor,   o,  The two  heads of
 (x x) the biceps,  p, Coraco-brachialis.   q q,
 The long head'of the  triceps extensor cubiti.
 rr, Teres  major.   ((,  Subscapulars.  11, Ex-
 tensores radiales.  u,   Supinator brevis-   v,
 The cut extremity of the pronator teres,   w,
 Flexor  sublimis perforatus.  x,  Part of the
 flexor  profundus,   y,  Flexor pollicis longus.
 z, Part of the flexor pollicis brevis-  4, Ab-
 ductor  minimi  digiti.   5, The  four lumbri-
 cales-
   Trunk-—6, Serrated extremities of the ser-
ratus anticus major*   7 1, Obliquus externus
abdominis.   8 8, The linea alba-   9, The um-
bilicus.   10,  Pyramidalis.  11 11,  The sper-
matic cord.   On the left side it is covered by 
232
Of the Muscles.
the cremaster.  12 12, Rectus abdominis.  13,
Obliquus internus-   14 14, he.   Intercostal
muscles.
   Inferior Extremities—a a,  The  graci.
lis.  b b,  Parts of the triceps,  c c, Pectialis.
dd, Psoas magnus-   e e, Iliacus internus. yj
Part of the glutaeus  medius-  g, Part of the
glutaeus  minimus,  h,  Cut  extremity  of the
rectus cruris,   ii, Vastus externus, k, Ten-
don of the rectus cruris.   / /, Vastus internus.
*  Sartorius muscle.   **  Fleshy origin of the
tensor vaginae faemoris or membranosus.  Its
tendinous  aponeurosis covers (i) the  vastus
externus in the right side,   m m, Patella, n n,
Ligament  or  tendon from it to  the  tibia, o,
Rectus  cruris,  p, Cruraeus.  q q, The tibia.
r r,  Part of the Gemellus or gastrocnemius ex-
ternus.*  fff, Part  of the soleus or gastroc-
nemius internus.  t, Tibialis anticus.  u, Ti-
bialis posticus,  v v, Peronaei muscles,  ww,
Extensor longus  digitorum pedis,  x x,  Ex-
tensor longus pollicis pedis-  y, Abductor pol-
licis pedis.

Fig-  2- The Muscles, Glands, he.  of the
   Left  Side of the  face and neck,  after the
   common Teguments and Platysma myoides
   have been taken off.
   a, The frontal muscle,   b, Temporalis and
temporal artery,   c,  Orbicularis palpebrarum.
d,  Levator labii  superioris alaeque nasi,  e,
Levator anguli oris,    f, Zygomaticus.   g, De-
pressor labii inferioris.  h,  Depressor  anguli 
 
 
Of the Muscles.           233
oris,   i, Birccinator.  k, Masseter.   11, Paro-
tid gland-  m, Its duct-   n, Sterno-cleido-mas-
toidseus.  o,  Part of the  trapezius,   p, Sterno-
hyoidaeus.  q,  Sterno-thyroidaeus.   r,  Omo-
hyoidaeus.  f,  Levator scapulas-  11, Scaleni.
u, Part of the splenius.

Fig.  3. The  Muscles  of the Face and Neck
  in  view after the exterior  ones  are taken
  away.
  a a, Corrugator supercilii.   b, Temporalis-
c, Tendon of  the levator palpebral  superioris-
d, Tendon of  the orbicularis palpebrarum,  e,
Masseter-  f,  Buccinator,  g,  Levator anguli
oris,   h,  Depressor labii superioris  alaeque na-
si,   i, Orbicularis oris-  k, Depressor anguli
oris.   1,  Muscles of the os hyoides.  m, Ster-
no-cleido-mastoidseus.

Fig.  4- Some  of the Muscles of the Os Hy*
        oides and Submaxillary Gland.
   a,  Part of the masseter muscle-   b,  Poste-
rior  head of  the  digrastic.   c,  Its anterior
head,  dd,  Sterno-hyoidaeus-  e,  Omo-hyoi-
daeus.  f, Stylo-hyoidaeus.   g,  Submaxillary
gland in  situ.

  Fig. 5. The Submaxillary Gland and Duct.
  a,  Musculus mylo-nyoidaeus.  b, Hyo-glos-
sus.   c, Submaxillary gland extra situ,  d, Its
duct.

             Plate  XXIV.
  Fig. 1. The  Muscles  immediately under
the common teguments  on the posterior part
                    G  g 
234
Of the Muscles.
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.—A A, Occipito-frontalis.   BT Attol-
lens a-urem.  C, Part of the orbicularis palpe-
brarum.  D, Masseter.   E, Pterygoidaeus in-
ternus.
  Trunk.—Right side.  FFF, Trapezius sen
cucullaris.  G G G G, Latissimus dorsi.  H,
Part of the obliquus externus  abdominis.
  Trunk,—Left  side..   I,  Splenius.  Kr Part
pf the complexus.  L,  Levator scapulae.  M,
Rhomboides.   N  N, Serratus  posticus inferi-
or.   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.  Sy  Part of the obliquus in-
ternus  abdominis.
  Superior  Extremity.—Right  side.  T,
Deltoides.  U, Triceps  extensor cubiti.  V,
Supinator  longus.  W  W, Extensores carpi
radialis lon-gior and brevior.   X X,  Extensor
carpi ulnaris.   Y  Y, Extensor  digitorum com-
munis.   Z, Abductor indicia   12 3, Exten-
sores pollicis.
  Superior Extremity.—Left side,  a, Su-
pra  spinatus.   b, Infra-spinatus.  c, Teres
minor,   d,  Teres major,  e, Triceps extensor
cubiti.  f f, Extensores carpi radiales.  g, Su-
pinator brevis.   h,  Indicator.   12 3, Exten-
sores pollicis.  i,  Abductor minimi digiti.   k,
Interossei.
  Inferior Extremity.—Right side.  1, Glu-
taeus maximus.  m,  Part of the Glutaeus me- 
Of the Muscles.           235
dius.   n,  Tensor vaginae femoris.  o, Graci-
lis,  p p,  Abductor femoris magnus.  q, Part
of the  vastus internus.  r, Semimembrano-
sus,   s, Semitendinosus-   t, Long head of the
biceps flexor cruris,  u u, Gastrocnemius ex-
ternus seu gemellus,  v, Tendo Achillis.  w,
Soleus seu  gastrocnemius internus.   x x, Pe-
ronaeus longus and brevis.  y, Tendons of the
flexor longus  digitorum pedis;—and  under
them * flexor brevis digitorum pedis-   z, Ab
ductor minimi digiti pedis.
   Inferior Extremity.—Left  side,  m, n,
o, p,  q, r, s,  t, v,  w w,  x x, y,  z, Point the
same parts  as in  the  right side,  a,  Pyrifor-
mis.   b b, Gemini,  c c,  Obturator internus.
d, Quadratus femoris.  e, Coccygaeus. f The
short head  of the  biceps flexor  cruris-  gg,
Plantaris.   h,  Poplitaeus.  i,  Flexor longus
pollicis pedis.

Fig.  2. The Palm of the Eeft 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, Ten-
dons of the  flexor sublimis perforatus, pro-
fundus perforans  and  lumbricales.   d, Ab-
ductor pollicis.  e e, Flexor pollicis longus-
f, Flexor  pollicis brevis. g, Palmaris brevis-
h, Abductor  minimi digiti.  i,  Ligamentum
carpiannulare.  k,  A probe put under the ten-
dons of the flexor digitorum sublimis; which
are perforated by  1, the  flexor digitorum pro-
fundus,   m m m m, Lumbricales.  n, Abduc-
tor pollicis. 
236           Of the Abdomen.
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 peronaeus brevis.  g, Tendons of the flex-
or digitorum  longus, with the nonus Vesalii.
h  h, The whole  of the  flexor digitorum bre-
vis.

       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,  c c, Sphincter ani.   d, Anus.
e,  Levator ani.   f f, Erector penis,  g g, Ac-
celerator urinae-  h, Corpus cavernosura ure-
thra?.

       Fig. 5. Muscles of the Penis.
   a a, b,  d, e e,  f f, h, point  the  same as in
fig. 4.  c, Sphincter ani.  gg,  Transversalis
penis.
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 sto-
mach,  and more properly scrobiculus cordis, to
the lower part of the trunk- 
             Of the  Abdomen.          237

  It is  distinguished into three divisions call-
ed regions; of these  the upper one, which is
called the epigastric region, begins immediate-
ly under  the sternum,  and extends to within
two  fingers breadth of the navel,  where the
middle or umbilical region begins, and reaches
to the  same  distance below the  navel.  The
third, which is called the hypogastric, includes
the rest of the abdomen, as far as the os pu-
bis.
   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 call-
ed epigastrium, and its two sides hypochondria.
The middle part of the next region is the um-
bilical 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  hypogastrium, and its sides are call-
ed inguina or groins.  The back part of the
abdomen  bears  the name of lumbar region-
   These  are the divisions of the lower belly,
which are necessary to be  held in remem-
brance, as they frequently occur in surgical
and anatomical writing.  We will  now proceed
to examine the contents of the abdomen; and
after having pointed out the names and  ar-
rangement of the  several viscera contained in
it, describe each of them separately-
   After  having   removed the  skin, adipose
membrane, and  abdominal muscles, we disco-
ver  the peritonaeum  or membrane  that  enve-
lopes all the  viscera of the lower belly-   This
being opened, the first part that presents itself 
238           Of the Abdomen.
is the omentum or  cawi, floating on the sur-
face of the intestines, which are likewise seen
every where loose and  moist, and making a
great number of circumvolutions through the
whole cavity of the abdomen.   The stomach
is placed in the  epigastrium, and under the
stomach is the pancreas.  The liver fills the
right hypochondrium,  and the spleen is situ-
ated in the left.   The  kidneys  are seen about
the middle of the lumbar region, and the uri-
nary bladder and parts of generation are seat-
ed in the lower division of the belly-

        Sect. I.   Of the Peritonaeum.

   The  peritonaeum is  a strong simple mem-
brane, by  which all the viscera of the abdo-
men are surrounded,  and in  some measure
supported.  Many anatomical writers, particu-
larly Winslow, have described it as being com-
posed of two distinct membranous laminae; but
their description seems to be erroneous. What
perhaps appeared to be a second lamina, being
found to be simply a cellular coat, which sends
off productions  to  the  blood-vessels passing
out of the abdominal cavity.   The aorta and
vena cava likewise derive a covering from the
same membrane,  which seems to be a part of
the cellular  membrane we have already de-
scribed.
  The peritonaeum, 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 ex- 
Of the Abdomen.          239
haling from its inner surface, and is returned
again into the circulation by the absorbents.
  This  moisture not only contributes to  the
softness of the  peritonaeum, but prevents the
attrition, and other ill effects which would
otherwise probably be occasioned, by the  mo-
tion 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 consti-
tutes  an ascites or  dropsy of the belly;  and
when by any means the exhalation is discon-
tinued, the peritonaeum thickens, becomes  dis-
eased, and the  viscera are sometimes  found
adhering to each other.
  The  peritonaeum is not a  very  vascular
membrane.   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
abdominal muscles.

        Sect. II.   Of the Omentum.

  The omentum,  epiploon, or cawl, is a dou-
ble membrane, produced from the peritonaeum.
It is  interlarded with fat, and adheres to the
stomach, 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 pelvis, 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; 
246           Of the Abdomen.
but at present we distinguish three  omenta,
viz. omentum magnum colico gastricnm, omen-
tum parvum hepatico gastricum, and omentum
colicum.   They all agree  in  being formed of
two very delicate  laminae,  separated by a thin
layer of cellular membrane.
   The omentum magnum  colico gastricum, of
which we have already spoken, derives its ar-
teries from the splenic and hepatic.  Its veins
terminate in the vena portae.  Its nerves, which
are very few, come from the  splenic  and he-
patic  plexus.
   The  omentum  parvum  hepatico gastricum,
abounds less  with fat than the great epiploon.
It begins at the upper part of the duodenum,
extends along the lesser curvature of the sto-
mach as far as the oesophagus, 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 describ-
ed by  Winslow,  through which the whole
pouch may easily be distended with air.* The
vessels  of the omentum parvum are  derived
chiefly  from the  coronary stomachic arteries
and veins.
   The  omentum  colicum  begins  at the fore
part of the ccecum and right side of the colon.
It appears as a  hollow conical  appendage to
these intestines, and usually terminates at the
back of the omentum magnum.   It seems to

  * This membranous bag, though exceedingly thin and trans-
parent,  is found capable of supporting mercury, thrown into ;t
by the same channel. 
Of the Abdomen.          241
be nothing more than a membranous coat  of
the cdecum and colon, assuming a conical shape
when distended with air.
   The uses of the omentum are not yet satis-
factorily 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 supposed, 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 muscu-
lar bag, in shape not unlike a bag-pipe,  lying
across the upper part of the abdomen, and in-
clining rather more to the left than  the  right
side.
   It has two orifices, one  of which receives
the end of the oesophagus,  and is called the
 cardia, and sometimes the left and upper ori-
fice of the stomach ; though its situation is not
much higher than the other,  which  is  styled
the right and inferior orifice,  and more  com-
 monly  the pylorus; both these openings are
 more elevated than the body of the stomach.
   The aliment passes down the oesophagus in-
to the stomach through the cardia, and after
 having  undergone  the  necessary  digestion,
 passes out at the  pylorus  where the intesti-
nal canal  commences.
   The stomach is composed of four tunics or
 coats, which are so intimately connected toge-
                    H h 
242            Of the Abdomen.
 ther that it requires no little dexterity in the
 anatomist to demonstrate  them.   The exterior
 one  is membranous, being derived from the
 peritonaeum.—The second is  a muscular tu-
 nic,  composed 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  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
 observed every  where  in the cavity of this
 viscus,  and more particularly  about the pylo-
 rus ;  where they seem to  impede the too has-
 ty exclusion of the aliment, making a conside-
 rable plait,  called valvula 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 li-
 quor has been supposed to be  secreted by cer-
 tain minute glands* seated in  the nervous tu-
 nic,  whose  excretory ducts  open on the sur-
 face  of the  villous coat.
   The arteries of the stomach called the gas-
 tric  arteries are  principally  derived from the
 cseliac;  some  of its  veins pass to the splenic,
 and others to the vena  portae;  and  its nerves
 are chiefly from the eighth pair or par vagum.

  * 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 satisfactorily demon-
strated in the human stomach ; and  the gastric juice is now more
generally believed to be derived from the exhalent arteries of the
stomach. 
Of the Abdomen.          243
  The account given of the tunics of the sto-
mach may be applied to the whole alimentary
canal; for both the oesophagus and intestines
are, like this viscus, composed of four coats.
  Before  we describe the  course of the ali-
ment and the  uses of the  stomach, it will be
necessary to speak of other parts  which assist
in the process of digestion.

       Sect. IV.   Of the  Oesophagus.

  The oesophagus  or gullet is a  membra-
nous and  muscular canal,  extending from the
bottom of the mouth to  the upper orifice of
the  stomach.—Its upper part where the ali-
ment is received is shaped somewhat  like a
funnel, and is  called the pharynx.
  From hence it  runs down close to the bo-
dies of the vertebrae as far as the diaphragm,
in which there is an opening through which ix
passes, and then  terminates  in  the  stomach
about the eleventh or twelfth vertebra  of the
back.
  The  oesophagus is plentifully supplied with
arteries from the  external  carotid, bronchial,
and  superior  intercostal arteries.; its  veins
empty themselves into the  vena azygos,  inter-
nal jugular, and mammary veins, he.
  Its  nerves  are  derived  chiefly from the
eighth pair-
  We likewise meet with a mucus in the oeso-
phagus, which every where lubricates  its in-
ner  surface, and tends to assist in deglutition.
—This mucus seems to be secreted by very
minute glands, like the  mucus in other parts
of the alimentary  canal. 
244           Of the Abdomen.
        Sect.  V.  Of the Intestines.

  The  intestines form a canal,  which is usu-
ally  six times  longer than the body to which
it  belongs.   This canal extends from the py-
lorus, 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
circumvolutions, 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 distin-
guished by different names.
   The  intestines are first distinguished into
two parts, one of which  begins  at the  sto-
mach, and is called the thin or small intestines^
from the  small size of the canal,  when  com-
pared 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 its subdivisions.—
The small intestines being distinguished into
duodenum,  jejunum, and ilium, and the larger
portion into caecum,  colon, and rectum.
   The small intestines fill the middle and fore
parts of the belly, while the large intestines
fill 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 pylo- 
Of the Abdomen.           245
rus and terminates in the jejunum, which  is a
part of the canal observed to be  usually more
empty than t;.e otiier intestines.—This appear-
ance 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 duode-
num and jejunum,  and has received its name
from  its   numerous  circumvolutions.   The
large  circumvolution of the ilium covers  the
first of the large intestines called the cajcum,*
which seems properly to belong to the colon,
being a kind of pouch ofabovufour fingers in
width, and nearly of the same length, having
exteriorly  a  little  appendix,  called appendix
cceci.
   The caecum 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 in-
testines.
   This intestine ascends by the  right kidney
to which it is attached,  passes under the hol-
low 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 sa-
crum, where, from its straight course, the ca-
nal begins to take the name of rectum.
   There are three ligamentous  bands  extend-
ing  through  the  whole  length  of the colon,

  * Anatomists have differed with respect to this division of the
intestines.—The method here followed is now generally adopted ;
but there are authors who allow the name of cacum only to the
little appendix, which has likewise been called the venniform ap-
pendix, from its resemblance to a worm in size and length. 
246           Of the Abdomen.
which, by being  shorter than  its two inner
coats, serve  to increase the plaits on  the in-
ner 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 call-
ed, because they  elevate the anus after dejec-
tion.   When these by palsy, or any other dis-
ease lose the power of contracting,  the  anus
prolapses; and  when the sphincter is affected
by similar causes, the faeces are voided invo-
luntarily.
   It has been already observed, that  the in-
testinal 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 valvules conniven-
ies.
   Some authors have considered  these plaits
as  tending to retard the motion of the faeces,
in order  to  afford more time  for  the  separa-
tion of the chyle; but  there are  others who
attribute to them a  different use: they con-
tend, that these valves, by being naturally in-
clined downwards,  cannot  impede the  descent
of the faeces, but that  they are intended to pre-
vent their return  upwards.
   They are probably destined for both  these
uses; for  although these folds incline  to their
lower side, yet the inequalities they occasion 
                Of the Abdomen.            247

in the  canal are sufficient  to retard, in some
measure,  the progressive motion of the faeces,
and to  afford a greater  surface for  the absorp-
tion of chyle, and their natural  position seems
to oppose itself to the return of the aliment.
   Besides these valvule 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 join-
ed to the  colon.   This valve  permits the  ali-
mentary 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.*
   Of the little vermiform appendix of the cae-
cum, it will  be sufficient to say,  that its uses
have 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 follicles.f  This  mucus  pro-
motes the descent of the  alimentary pulp,  and
in some measure defends the  inner surface of

  * This  is  not  invariably the case,  for the contents of a gly-
ster have been found not only to reach the  small intestines, but
to be voided at the mouth.  Such instances, however, are not
common.
  f Some writers have distinguished  these glands into miliary,
lenticular,  &c.—Brunner and Peyer were  the  first anatomists
who described the  glands of the intestines, and their descrip-
tions were chiefly taken from animals,  these glandular appear-
ances not seeming to have been hitherto satisfactorily pointed out
in the human subject.—It is now pretty generally believed, that
the mucus which every where lubricates tire alimentary canal, is
exhaled from the minute ends  of arteries; and that these ex-
tremities first open into a hollow vesicle, from whence the depo-
sited juice of several branches flows out  through one commo.t
orifice. 
248
Of the Abdomen.
the intestines from the irritation  to  which it
would,  perhaps, otherwise be continually  ex-
posed from tiie  aliment;  and which,  when in
a  certain degree,  excites  a painful  disorder
cahed  colic, a name  given to the disease,  be-
cause us most usual seat is in  the intestinum
colon.
   The intestines are likewise frequently dis-
tended with air, and this distention sometimes
occasions pain, and constitutes the  flatulent
colic.
   The arteries of the  intestines are  continu-
ations  of the  mesenteric  arteries,  which  are
derived in two considerable branches  from  the
aorta.—The redundant blood is carried back
into the vena portarum.
   In  the rectum the veins are called  hemor-
rhoidal, and are there  distinguished into inter-
nal 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 hemorrhoids takes place.
In this disease they  are  sometimes ruptured;
and the discharge  of blood  which  consequent-
ly follows,  has probably  occasioned them to be
called hemorrhoidal veins.
   The nerves  of the intestines  are derived
from the eighth pair.

        Sect. VI.    Of the Mesentery.

   The name of the mesentery  implies its sim-
ulation amidst  the intestines.   It is  in fact a 
Of the Abdomen,            249
part  of the  peritonaeum, being a  reduplica-
tion * of that membrane  from each  side of the
lumbar vertebrae, to which it is firmly attach-
ed,  so that it  is formed  of two laminae,  con-
nected to each  other by cellular membrane.
   The intestines,  in their different circumvo-
lutions,  form  a  great number of arches,  and
the  mesentery 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 accom-
panies the small intestines is the  mesentery,
properly so called ; but those parts of it which
are  attached to the colon and rectum are  dis-
tinguished by  the names  of meso-colon and me-
so-rectum.
   There are many conglobate  glands dispers-
ed  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 intestines.
                       I i

   *  He who  only  reads of the  reduplication of membranes,
will perhaps not easily  understand how the peritf nxum and
pleura  are reflected over the viscera in their several cavities ;
for one of these serves the same purposes in the thorax that
the other does in the abdomen. This disposition, for the dis-
covery of which we are indebted  to modern anatomists, con-
stitutes a curious part of anatomical knowledge : but the stu-
dent, unaided  by experience, and  assisted only by what the li-
mits of this work would permit us  to say on the occasion, would
probably imbibe only confused ideas of the matter ; and  it v-ill
perfectly answer the present purpose, if he considers the me-
sentery  as a membrane attached bv one of its sides to the lum-
bar vertebrae, and by the other to  the intestines. 
250          Of the Abdomen.

  This membrane, by its attachment  to  the
vertebrae, serves to keep the intestines in their
natural situation.  The idea usually formed of
the colic  called miserere, is  perfectly errone-
ous ;  it being  impossible  that the  intestines
can be  twisted,  as many suppose they  are, in
that disease, their attachment to the  mesente-
ry  effectually preventing such an accident—
but a disarrangement  sometimes takes place
in the intestinal canal itself, which is produc-
tive of disagreeable and  sometimes fatal con-
sequences.—This is by an  introsusception 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  mo-
tion of the  intestines (by  which is meant the
progressive motion of the faeces  downwards)
is inverted, and what is called  the iliac passion
takes place.  The same effects may  be occa-
sioned: by a descent  of the intestine,,  or of the
omentum either with it or by  itself,  and thus
constituting what is  called an hernial rupture;
a term by which in general is meant the falling
down or protrusion of any part  of the intes-
tine or omentum, which ought naturally to be
contained within the cavity of  the belly.
   To convey an idea of the manner in which
such a descent takes place, it will be necessa-
ry to  observe, that the  lower edge of the  ten-
don of the  musculus  obliquus externus, is
stretched  from the fore-part  of the  os ilium
or haunch-bone of the os pubis, and  consti-
tutes what is called PouparVs  or Fallopius's li- 
               Of the Abdomen.           251

 gament, forming an opening, through which
 pass the great crural  artery and  vein.  Near
 the  os  pubis the same tendinous fibres are se-
 parated 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.  In consequence
 of violent efforts, or perhaps of natural causes,
 the  intestines  are  found sometimes  to pass
 through these openings; but the peritonaeum
 which incloses them when  in their natural ca-
 vity, still continues to surround them even in
 their descent.  This membrane  does not be-
 come torn  or  lacerated  by  the violence, as
 might be easily imagined; but its dilatibility
 enables it to pass out  with the viscus,  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 ;*
 and  scrotal, if in the  scrotum.   Different names
 are likewise given to  the hernia as the con-
 tents of the sac  differ, whether of omentum
 only or intestine, or both:—but  these defini-
 tions 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

  * The hernia congenita will be considered with the male or-
gans of generation, with which it is intimately connected. 
252           Of the Abdomen.

like  a dog's tongue, with  its point stretched
out towards the spleen, and its other end  ex-
tending towards the duodenum.  It is about
eight fingers breadth in length, two  or three
in width, and  one in thickness.
   This viscus, which is of a yellowish colour,
somewhat  inclined  to  red,  is covered with a
membrane  which it derives from the peritonae-
um.   Its arteries, which are rather numerous
than large, are derived chiefly from the sple-
nic and hepatic, and its veins  pass into  the
veins of the same  name.—Its nerves are  de-
rived from the intercostal.
   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 pro-
perties, does  not seem to differ from the sali-
va.  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 common excretory duct (first
discovered by Virtsungus in  1642),  which
runs through  the middle of the gland,  and is
now usually  called ductus pancreaticus Virt-
sungi.   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 being of a
mild and insipid nature, serves to dilute  the
alimentary pulp, and  to incorporate it more
easily with the bile. 
              Of the Abdomen.           253


         Sect. VIII.   Of the Liver.

   The liver is a viscus  of considerable size,
and  of a reddish  colour;  convex  superiorly
and  anteriorly where  it is  placed under the
ribs  and diaphragm, and of an unequal  sur-
face  posteriorly.  It is  chiefly situated in the
right hypochondrium, and under the false ribs;
but it likewise extends into  the  epigastric re-
gion, where it borders upon the stomach.   It
is covered by a production of the peritonaeum,
which serves to attach it by three of its redu-
plications to the false ribs.  These reduplica-
tions are called ligaments, though  very differ-
ent in their  texture from what are called by
the same name in other parts of the body. The
umbilical cord, too,  which in the foetus is per-
vious,  gradually becomes a  simple ligament
after birth ; and, by passing to  the liver, serves
likewise to secure it in its situation.
   At the posterior part of this organ where
the umbilical vessels enter, it is found divid-
ed 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 winch go to the
liver pass in  at the fissure we have mention-
ed ; and  the production of the  peritoneum,
which invests the liver, was described by Glis-
son,  an English anatomist, as accompanying
them in their passage, and surrounding them
like a  glove ;  hence this production has been
commonly  known by the name of capsula  of
Glisson: but it appears to be chiefly a continu- 
 254           Of the Abdomen.

 ation of the cellular membrane  which covers
 the vena portae 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
 hepatic artery and the  vena portae.  This is
 contrary to the mode of  circulation  in  other
 parts, where veins only serve  to carry off  the
 redundant blood : but in this viscus the hepa-
 tic artery, which is derived from the caeliac, is
 principally  destined for  its nourishment; and
 tfee vena portae,  which is formed by the union
 of the veins from most  of the abdominal vis-
 cera, furnishes the blood from which the bile
 is chiefly to be separated; so that these two
 series of  vessels serve very distinct purposes.
 The vena portae, as it is ramified 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 arteries, while
 as  the latter it prepares  it  for secretion.
   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
 manner of  which  mention will  be made in
 another place, is conveyed out of this organ
 by very minute excretory  ducts,  called poribi-
 liarii; these uniting together like the excreto-
ry ducts in the pancreas, gradually form larger
 ones, which at length terminate in a  considera-
 ble canal  called ductus hepaticus. 
Of the Abdomen.           25 5s.
       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 peritonaeum.   The
 interior, or villous coat, is supplied with a mu-
 cus that defends it from the acrimony of the
 bile.   These two coverings are intimately con-
 nected by means of cellular membrane, which
 from its firm glistening appearance  has  gene-
 rally been spoken of as a muscular tunic.
   The gall-bladder is supplied  with bloods
 vessels  from  the hepatic arteries.   These
 branches are called  the  cystic  arteries,  and
 the cystic veins carry 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 described as the excretory duct  of the  li-
 ver; and forming one common canal, takes the
 name of ductus  coledochus communis, through
 which both the cystic and hepatic bile  are dis^
 charged into the duodenum.  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  cecono-
my serves two  useful purposes;—to promote
the discharge of bile and to prevent its return. 
256          Of the  Abdomen.

  The bile may be defined to be a natural li-
quid soap, somewhat unctuous and bitter, and
of a yellowish colour, which easily mixes with
water, oil, and vinous spirits, and is  capable
of dissolving resinous substances.  From some
late experiments  made by M. Cadet,* it  ap-
pears to be formed of an animal  oil, combined
with the alkaline base of sea-salt, a salt of the
nature of milk,  and a  calcareous earth which
is slightly ferruginous.
   Its definition  seems  sufficiently to point  out
the uses for which it is intended^   It blends
the alimentary mass,  by dividing  and attenu-
ating it; corrects the  too  great disposition to
acescency,  which the aliment acquires in  the
stomach; and finally,  by its  acrimony, tends
to  excite the peristaltic motion of the  intes-
 tines.
    After what has been said, it will be  conceiv-
 ed 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-bladder.   These two biles, however,
 do not essentially differ from each other.  The
 hepatic bile indeed 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

   * Mem. de 1* Acad, des Sciences, 1767.
   f The ancients, who were not acquainted with the real use
 of the liver, considered the bile as an excrementilious and use-
 less fluid. 
               Of the  Abdomen.           257

has occasioned no  little controversy ampngst
anatomical writers.  There are some who con-
tend, 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 ves-
sels, 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 hepaticystic ducts;
but it is certain that no such ducts exist.—In
obstructions of the cystic duct, the gall-blad-
der has been found shrivelled and empty: so
that we may consider the gall-bladder as a reser-
voir of hepatic bile ; and that  it is an establish-
ed fact that the whole of the bile contained in
the gall-bladder is derived from the liver; that
it passes from the  hepatic to  the  cystic duct,
and from that to the gall-bladder.   The differ-
ence in the colour, consistence,  and taste of
the bile,  is merely the consequence of stagna-
tion  and absorption.  When the stomach is
distended with aliment, this  reservoir under-
goes a certain 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 affected, and at such times dis-
charges itself of its contents.
  Sometimes the  bile  concretes in the gall-
bladder,  so  as to form what are  called gall-
                    Kk 
258           Of the Abdomen.
 stones.*   When these  concretions pass  into
 the cystic duct, they  sometimes occasion ex-
 quisite pain, by distending the  canal  in  their
 way to the duodenum; and by  lodging in the
 ductus choledochus communis,  and  obstruct-
 ing 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 colour, and about five  or  six fingers
 breadth in length, and three in width,  situated
 in the left hypochondrium, between the  sto-
 mach  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 caeliac, supplies this viscus with blood,  and
 a vein of the same name  carries it back into
 the  vena portae.
   Its  nerves  are  derived from  a  particular
 plexus called the  splenic,  which is formed by
 branches of the intercostal nerve, and by  the
 eighth 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

  * These concretions sometimes remain in the gall-bladder
 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  complained of the
jaundice, nor  of any disorder which he could attribute to that
 cause. Med.  Trans. Vol. ii. 
              Of the Abdomen.           259

wrote professedly on the bones, determined its
use to be that of secreting the  synovia;  and
the late Mr. Hewson imagined, that it concur-
red 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 pre-
paration of the  bile.   This is the opinion of
the  generality of modern physiologists;  and
the great quantity  of blood with  which it is
supplied, together with the course of its veins
into the vena portae, seem to  render  this no-
tion probable.

Sect. XI. Of the  Glandule Renale-s, Kidneys,
                and Ureters.

   The glandulae renales, which were  by the
ancients supposed to secrete the atra bilis, and
by them  named  capsula atrabilares,  are  two
flat bodies of an irregular figure, one on each
side between the kidney and the aorta.
   In the foetus they  are as large as the kidneys:
but they do not increase afterwards in propor-
tion to those parts; and in adults and old peo-
ple  they are generally found shrivelled, and
much wasted.  They  have their  arteries and
veins.   Their arteries usually arise from the
splenic or the emulgent, and sometimes from
the aorta; and their veins go to the neighbour-
ing veins, or to the vena cava.  Their nerves
are branches of the intercostal. 
260           Of the Abdomen.
   The  use of these parts is not yet perfectly
known.  In the foetus  the  secretion of urine
must be in a very small quantity,  and a part
of the blood may perhaps then pass through
these channels, 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 verte-
brae.  Each 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 as-
cendens.   They  are surrounded  by  a good
deal of fat, and receive a coat from the peri-
tonaeum ; and when  this is  removed,  a very
fine  membrane  is  found investing their sub-
stance and the vessels which ramify through
them.
   Each kidney has a considerable  artery and
vein,  which are called the emulgent.  The ar-
tery  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.*  The outer part is glan-
dular or cortical,  beyond this is the vascular
  * The kidneys in the foetus are distinctly lobulated ; but in
the adult they become perfectly firm, smooth, and regular. 
Of the Abdomen.           261
or tubular substance, and the inner part is pa-
pillary or membranous.
   It is in the cortical part of the kidney  that
the secretion is carried on; the urine being
here received from the  minute extremities of
the capillary arteries, is conveyed out of this
cortical substance by an infinite number of ve-
ry small cylindrical canals  or excretory  ves-
sels, which  constitute the tubular part.  These
tubes, as  they  approach the inner substance
of the kidney gradually unite together;  and
thus forming larger  canals, at  length  termi-
nate in ten or twelve little protuberances  call-
ed papilla, the orifices of which may be seen
without the assistance of glasses.   These pa-
pillae  open  into a  small  cavity  or reservoir
called the pelvis of the  kidney, and formed by
a distinct membranous  bag which  embraces
the papillae.  From this pelvis the  urine is
conveyed 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
common  writing-pen.  They are  somewhat
curved  in their  course  from the kidneys,  like
the letter/, and at length terminate in the  pos-
terior and almost inferior part of the bladder,
at some distance from each other.  They  pass
into the bladder in  the  same manner as the
ductus choledochus communis passes into the
intestinum duodenum, not by a direct passage,
but by an  oblique course between the  two
coats;  so that the discharge of  urine into the
bladder is promoted, whilst  its  return is pre- 
262           Of the Abdomen.

vented.  Nor does this mode of structure pre-
vent the passage of fluids only from the blad-
der into the ureters,  but likewise air:—for  air
thrown into the bladder inflates it, and it con-
tinues to be distended if a ligature is passed
round its neck; which seems to prove suffici-
ently 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,
situated in  the pelvis, between the  os pubis
and intestinum rectum in men, and  between
the os pubis and uterus in  women.  Its up-
per and widest part is usually called  the bot-
tom, its narrow part the neck of the bladder;
the former only is covered by the peritonaeum.
  The bladder is formed  of three coats, con-
nected together by  means  of cellular mem-
brane.  The external or peritonaeal, 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 bladder, but not so
as to form a distinct muscle, or sphincter, as
the generality of anatomists have hitherto sup-
posed.
  The inner coat, though much smoother, has
been said to resemble the  villous tunic of the
intestines, and like  that  is  provided with a
mucus, which defends it against the acrimony
of the urine. 
               Of the Abdomen.           263

   It will  be easily  conceived from what has
 been said, that the kidneys are two glandular
 bodies, through which a saline and excremen-
 titious 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 ac-
 cumulated, so that the bladder is distended in
 a certain degree, it excites in us a certain sen-
 sation, which brings  on as it were a voluntary
 contraction of the bladder to promote its  dis-
 charge.—But this contraction is  not  effected
 by the muscular fibres of the bladder alone:
 for all the abdominal muscles contract in obe-
 dience to  our will, and press downwards all
 the viscera of the lower belly ; and these pow-
 ers being united, at length overcome the re-
 sistance  of the fibres surrounding  the neck of
 the bladder,  which dilates and affords a  pas-
 sage to the urine through the urethra.
   The frequency of  this evacuation depends
 on  the quantity of urine secreted; on the de-
 gree of acrimony it possesses; on the size of
 the bladder,  and on its degree of sensibility.
   The urine varies  much in its colour  and
 contents.  These varieties depend, on age, sex,
 climate, diet, and other circumstances.  In in-
 fants it is generally a clear watery fluid, with-
 out smell or  taste.  As we advance in life, it
 acquires  more colour and smell,  and becomes
 more impregnated with salts.  In old people
 it becomes still more  acrid and fetid.
  In a healthy state it is nearly of a straw co-
lour,—After  being kept for some time, it  de- 
264           Of the Abdomen.
posites  a tartarous  matter,  which is found
to be composed chiefly of earth and salt, and
soon incrusts the sides of the vessel in which
it is contained.  While this  separation is tak-
ing place,  appearances like  minute fibres  or
threads of a whitish  colour may be  seen in the
middle of the urine, and an oily scum observ-
ed floating on its surface.  So  that the most
common appearances of the urine  are suffici-
ent to  ascertain that it is  a watery substance,
impregnated with earthy,  saline, and oily par-
ticles.
  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  parti-
cles  contained in it: so that an increased pro-
portion of those parts will constantly give the
urine a higher colour, and add to  the quanti-
ty of sediment.
  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  like-
wise occasioned by  the different state of the
urinary vessels, by  which we mean the  chan-
nels  through  which it is separated from the
blood, and conveyed through the  pelvis into
the ureters.  The causes of  calculous concre-
tions in the urinary passages, are to be looked
for in the natural constitution of the  body,
mode of life,  he.
  It having  been observed,  that after drink-
ing any light wine or Spa water, it very soon 
               Of the Abdomen.          26 5

 passed off by urine, it has been supposed by
 some, that the urine is not altogether  convey-
 ed to the bladder by  the  ordinary  course  of
 circulation, but that there must certainly exist
 some other shorter means of communication,
 perhaps by certain  vessels between the sto-
 mach 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  ligature round the
 emulgent arteries, and then sew up the  abdo-
 men, and give him even the  most diuretic li-
 quor to drink, the stomach  and other  chan-
 nels 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
 ligature is thrown round  the two ureters. This
 experiment 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 eva-
 cuation of urine: but  the discharge seems to
 be merely the effect of the stimulus they  occa-
 sion ;  by which the bladder and urinary parts
 are solicited to a more copious 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 is kept
 up, will  continue :  nor will this appear won-
 derful, if we consider the great capacity of the
vessels that go to the kidneys ; the constant sup-
ply of  fresh blood that is essential to health ;
and the rapidity  with  which it  is incessantly
                   L 1 
266           Of the  Abdomen.
circulated through the heart to all parts of the
body.

         Sect. XIII. Of Digestion.

  We are now  proceeding to speak of diges-
tion, 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 under-
goes for the formation of chyle :—these chan-
ges 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 con-
tinued over  the whole  inner  surface  of the
mouth, like a fine  and delicate membrane.—
Besides 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 secured in their sockets.   A simi-
lar  substance covers the  roof of the mouth,
and forms what is  called the velum pendulum
palati,  which is fixed to  the extremity of the
arch formed by the ossa maxillaria and ossa  pa-
lati, and terminates in a soft, small, and coni-
cal body, named uvula ; which appears, as it
were, suspended from the middle  of the arch
over the basis of the tongue. 
              Of the Abdomen.           267

  The  velum pendulum  palati performs the
office of a valve  between the cavity of the
mouth and  the pharynx, being moved by  se-
veral muscles.*
  The  tongue  is composed of several mus-
clesf which enable it to perform  a variety  of
motions for  the articulation  of the  voice ;  for
the purposes of mastication; and  for convey-
ing the aliment into the  pharynx.  Its upper
part is covered with papillae, which constitute
the organ of  taste,  and are easily to  be dis-
tinguished;  it is covered  by the  same mem-
brane  that lines the inside of the  mouth, an<J
which makes  at its inferior part towards its ba-
sis  a reduplication called frtenum.
  Posteriorly, under the velum palati, and  at
the basis of the tongue, is the pharynx : which
is the  beginning of the oesophagus, stretched
out every way,  so as to resemble the  top of a
funnel, 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 oesophagus.
  The pharynx is constantly moistened by a
fluid, secreted by two considerable glands call-
ed the tonsils, one on  each side of the velum
palati.  These glands, from their supposed re-

  *  These are the  circumflexus palati,  levator palati mollis,  pa-
lato-pharyngceus, constrictor isthmi fauciu.m and azygos uvulae.
See pages 191, 192, 193.
  f  These are, the genio-glossus,  hyo-glossus, lingualis, and
stylo-glossus.  Seepage 191. 
26&            Of the Abdomen.

semblance to almonds, have likewise been call-
ed amygdalus.
  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
cars.   They are two  in number,  one on each
side under the os malae:  and they are of the
conglomerate  kind;   being  formed  of  many
Smaller glands, each of which sends out a very
small excretory 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 in-
troduced.—Besides these, the maxillary glands,
which are placed near the inner surface of the
angle of the lower jaw on each side ;  the sub-
lingual glands, which are situated at the root
of the  tongue ;  the glands of the palate, which
are seated in  the velum  palati;  and those of
the cheeks, lips, he.  together with many other
less considerable ones,—pour the saliva into
the mouth  through  their  several excretory
ducts.
  The saliva, like all  the other humors  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 parti-
cles.
  The uses of the saliva seem to be to moisten
and  lubricate  the  mouth, and to assist in re- 
              Of the  Abdomen.           269

during 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  neces-
sarily occasion a continual waste and dissipa-
tion  of  its several parts.  A great quantity is
every day thrown off  by the insensible perspi-
ration and other discharges ; and were not these
losses constantly recruited by a fresh supply of
chyle, the body would soon effect  its own dis-
solution.  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
attention may not he  diverted from the  neces-
sary 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 in the stomach, which
induces us to wish for solid food; and which
likewise serves to point out the proper quan-
tity, and time for taking it.   In describing the
stomach, mention was made of the gastric juice,
as every where lubricating its inner coat.  This
humor  mixes itself with the aliment in the sto-
mach, and helps to prepare it for its passage
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 re-
quired to assist in the process of digestion, and
to afford that  moisture to the body, of which
there is such  a constant dissipation.—Thirst
induces us to  take  this  necessary supply of 
270
Of the Abdomen.
drink ; and the seat of this sensation is in the
tongue,  fauces, and oesophagus, 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 acrimonious by any natural
causes, never fails particularly to affect  these
parts, and  the whole alimentary 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 dis-
sipated.
   It has been observed,  that the aliment un-
dergoes  some preparation in the mouth before
it passes into the stomach ;  and this prepara-
tion is the effect of mastication.   In treating of
the upper and lower jaws, mention was made of
the number and arrangement of the teeth.   The
upper jaw was described as being immoveable ;
but the lower jaw was spoken of as being capable
of elevation 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 between the teeth till it  is perfectly divid-
ed, and  reduced  to  the  consistence  of  pulp.
The incisores  and  canini divide it  first into
smaller pieces, but it is between the surfaces of
the dentes  molares 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 
              Of the  Abdomen.           271

muscles that move the lower jaw, pour out.their
saliva: 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 oesophagus, 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
aliment, whether solid or liquidr may pass  into
them, whilst the pharynx alone is dilated to re-
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 oesophagus—in the act of swal-
lowing ; therefore, if the larynx (for so the up-
per part of the trachea is  called) is  not closed,
the aliment will pass into  it in its way to the
oesophagus.  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 oesopha-
gus presses down this cartilage, which then co-
vers the glottis or opening of the larynx ;  and
at the same time the velum palati being capable
of some degree of motion, is drawn  backwards
by its muscles, and closes  the openings into the
nose and the Eustachian tubes.—This,  howe-
ver, is not all.  The larynx, which  being com-
posed of cartilaginous rings, cannot fail in its
ordinary state to compress the membranous ca-
nal of the oesophagus, is  in the act of degluti-
tion carried forwards and  upwards by muscles 
27,2           Of the Abdomen,
destined for that purpose ;  and consequently
drawing the fore-part of the pharynx with  it,
that opening is fully dilated.   When the ali-
ment has reached the pharynx, its descent is
promoted by its own proper weight, and by the
muscular fibres of the oesophagus, which con-
tinue to contract from above downwards, until
the aliment has reached the stomach.    That
these fibres have no inconsiderable share in de-
glutition,   any  person  may  experience,  by
swallowing with his head downwards, when the
descent of the aliment cannot possibly  be  ef-
fected 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
introduced into the trachea, it  never fails  to
produce a violent cough, and sometimes the
most alarming symptoms.   This  is liable  to
happen when we laugh or speak in the act  of
deglutition : the food is then said to have passed
the wrong way.   And indeed this is not im-
properly expressed: for death would soon fol-
low, if  the quantity of aliment introduced into
the trachea should be sufficient to obstruct the
respiration only during  a very short time ;  or
if the irritating particles of food  should not
soon  be thrown up again  by means of the
cough, which in these  cases very seasonably
increases  in proportion to the degree of irrita-
tion.
   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 
              Of the Abdomen.          273

aliment would return through  the  nose, as is
sometimes 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  disease  or  any other  causes
have not this part perfect,  swallow with diffi-
culty.
   The  aliment, after having been  sufficiently
divided by the action of the teeth, and attenu-
ated by the saliva, is received into the stomach,
where it  is destined to undergo a more consi-
derable 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 membranous bag, surrounded by the abdo-
minal viscera, and with  a certain degree of na-
tural heat, the aliment undergoes a constant
agitation by means of the abdominal muscles
and of the diaphragm, and  likewise by a cer-
tain 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 pas-
sage 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,
                   M m 
274 '
Of the Abdomen.
be  in  some  degree digested *.   Animals,  or
parts of animals, possessed of the living prin-
ciple,  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 it-
self formed  for the digestion of its contents;
the process of  digestion appearing to be conti-
nued after death.   This is confirmed by what
happens in the  stomachs of fishes :   they fre-
quently  swallow,   without  mastication,  fish
which are larger than the digesting parts of their
stomach can contain; and in  such  cases,  that
part which is taken into the stomach is more


   * The Abbe Spallanzani, who has lately written upon di-
gestion, finds, from a variety of experiments, made upon quadru-
peds, birds, and fishes, that digestion goes on for some time after
death,  though far less considerable than in living animals ; but
heat is necessary in many animals, or at least promotes  it in a
much greater degree. He found also, that when the stomach
was cut out of the body, it had somewhat of the power of  diges-
tion, 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,
©r much eroded after death.  There was often a  little erosion,
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 excoriation ; and the injury in all
of them was at the inferior part, or great curvature.  The coats
of the stomach suffer less after 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 
               Of the Abdomen.           275

or  less  dissolved, while that part  which re-
mains  in the  oesophagus 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 secreted in the goats  of the  sto-
mach,  which is poured into  its cavity,  and
there animalizes the food, or assimilates it to
the nature of blood.
   From  some late experiments by M. Sage, *
it appears, that inflammable air has the proper-
ty of destroying and dissolving the animal  tex-
ture : and as we swallow with the  substances
which serve us for food  a great quantity of at-
mospherical  air, M.  Sage thinks it possible,
that dephlogisticated, which is its principle,
may be  converted in the stomach into inflam-
mable  air, or  may modify into inflammable air
a  portion  of the oily  substance  which is
the principle of aliments.  In this case, would
not the inflammable air (he asks), by dissolv-
ing  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 converted into a greyish pulp, which is usu-
ally called chymus,  a word of Greek etymolo-
gy, signifying juice, and some  few milky or
chylous  particles begin  to appear.—But  the

   *  Hist,  de l'Academie royale  des Sciences, &c. ppur 1784*
mem. 15. 
276           Of the Abdomen.
term of its residence in this bag is proportion-
ed to the nature of the aliment, and to the state
of the stomach and its juices.  The thinner and
more perfectly digested parts of the  food pass
by a little at a time into the duodenum, through
the pylorus, the fibres of which relax to afford
it a passage;  and the grosser and less digested
particles remain in the  stomach, till they ac»
quire a sufficient fluidity to pass into the intes-
tines, where the nature  of the chymus  is per-
fectly 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 ali^
mentary pulp, which they  still farther attenu-
ate and dissolve, and into which they seem  to
infuse new properties.
  Two matters very different from each otheu
in their nature  and destination,  are  the  result
of this combination.—One of these, which is
composed  of the liquid  parts  of the aliment,
and of some  of its  more  solid particles, ex-
tremely divided and  mixed with the  juices we
have described, constitutes a very mild, sweet,
and whitish fluid, resembling milk,  and distin-
guished by the name of chyle.  This fluid is ab-
sorbed by the lacteal veins, which convey it in-
to the circulation, where, by being assimilated
into the nature of blood, it affords that  supply
of nutrition, which the continual waste  of the
body is found to require.—The other is the re-
mains of the  alimentary mass deprived of all
its  nutritious   particles, and  containing only
such  parts as  were rejected by  the  absorbing
mouths of the lacteals.    This grosser part, 
                  Of the Abdomen.           277

    called the faces, passes on through the course
    of the  intestines, to  be voided  at the anus,
    as will be explained hereafter; for this process
•    in the ceconomy 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  attended to.
      It has been already observed, that the intes-
    tinal canal is five or six times as long as the bo-
    dy, 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 another extending itself upwards.   It  was
    noticed likewise, that the inner coat of the in-
    testines, by being more capacious than their ex-
    terior tunics, formed a multitude of plates plac-
    ed at a certain distance from each other,  and
    called valvule  conniventes.  Now this disposi-
    tion will be found  to afford a farther proof of
    that divine wisdom, which the anatomist  and
    physiologist cannot fail to discover in all their
    pursuits.—For if the intestinal canal was much
    shorter than it naturally is; if instead of the
    present circumvolutions it passed in a  direct
    course from the stomach ;  and if its inner  sur-
    face was smooth and destitute of valves ; the
    aliment would consequently pass with great ra-
    pidity to the anus, and sufficient time would be
    wanting to assimilate the chyle, and for the ne-
    cessary 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 circumvolutions of 
278
Of the Abdomen.
the  intestines,  the inequality of their internal
surface,  and the course of the aliment through
them, all concur  to perfect  the separation of
the chyle from the faeces,  and to affbrd the ne-
cessary nourishment to the body.

Sect.  XIV.   Of the Course of the Chyle, and
           of the LympJiatic 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 Asellius in  1622, * pass obliquely through
the  coats of the  intestine,  and  running along
the  mesentery, unite as they advance, and form
larger branches, all of which pass  through the
mesenteric  or conglobate glands, which are ve-
ry numerous in the human subject.    As they

   * 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 con-
sidered them as serving to convey the chyle from the intestines to
the liver ; for before the discovery of the thoracic duel,  the use
of the liver was universally supposed to be that of converting the
chyle into blood.  But the discovery of the thoracic duct by Pec-
quet, not long after, corrected this error.  Pecquet very candidly
confesses, that this discovery accidentally arose from his observ-
ing 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 sus-
pected to be chyle, and afterwards traced to its source from the
thoracic duct:  this duct had been seen near an hundred years be-
fore  in a horse by Eustachius, who speaks of it as a vein of  a
particular structure, but without knowing any thing of its termi-
nation or use. 
               Of the  Abdomen.          279

run  between the intestines and these glands,
they are styled vena lactee primi generis: but
after leaving these glands, they are found to be
less numerous, and being increased in size, are
then called  vene lactee secundi generis, which
go to deposite 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
vertebrae, being covered by the pleura.   Some-
times it is found divided into two branches ; but
they usually unite again into one canal, which
opens into the left subclavian vein, afterhaving
run a little way in  an oblique  course between
its coats.   The subclavian vein communicates
with the vena cava, which passes  to the right
auricle oi" the heart.
  The lower part of this duct being usually larg-
er than any other  part of it, has been named
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 considera-
ble in proportion  to the size of the duct, than it
usually is in the human subject, where it is not
commonly  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
* Hewsnn's Exn. Inq.  Part II. 
280
Of the Abdomen.
any other quadruped that is killed two or three
hours after feeding upon milk, for then they
appear filled 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 of-
fice  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 applied to that of the other.
   The lymphatic  veins*  are minute  pellucid
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

  * The arteries in their course through the body becoming gra-
dually too minute to admit the red  globules of the blood, have
then been styled capillary or lymphatic arteries.  The vessels which
are here described as constituting the lymphatic  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 having been attributed to the red veins.  But
we know that the lymphatic veins are not continuations of the lym-
phatic 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 likewise
as absorbents :—but it seems to have been clearly proved, that the
red veins do absorb nowhere but in the cavernous  cells of the
penis, the erection of which is occasioned by a distention of those
cells with arterial blood. 
               Of the Abdomen,           281

chyli, which may be  considered as the great
trunk  of the lymphatic system.  The lacteals
open into it near the same place ; and the lym-
phatics, 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 termi-
nate in the left  subclavian vein.   The lympha-
tics from the right side of the neck, thorax, and
right arm, he.  terminate in the right subclavi-
an vein.
  As the lymphatics  commonly lie close to the
large blood-vessels,  a ligature  passed round
the crural artery in a  living animal,  by includ-
ing the lymphatics, will  occasion a  distention
of these vessels below the ligature, so as to de-
monstrate them with ease ;  and a ligature pass-
ed round the thoracic duct, instantly after kill-
ing an animal, will, by stopping the course of its
contents into the subclavian  vein, distend not
only ihe lacteals, but also the lymphatics in the
abdomen and lower extremities, with their na-
tural fluids. *
  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 very strong; and their great power of  con-
traction, after undergoing  considerable disten-
tion, together with the irritability with which
Baron Haller found them to be enduedf, seems
                   N n

   * In the dead body they may be easily demonstrated by open-
ing 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 then be punctured, and
mercury introduced into it through a blow-pipe.
  f  Sur le movement du sang Ex. 295, 298. 
282           Of the  Abdomen.

to render it probable,  that, like the blood-ves-
sels, 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
inflammation of which  they  are susceptible;
and  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 prevent 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 observed, that the  lymphatics  pass
through similar glands in their way to the tho-
racic duct.  These glands are all of a conglo-
bate 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 surface*
and cavities in all parts  of the body as  absorb-
ents.   This is a fact now universally allowed;
but how the fluids they absorb are poured into
those cavities,  is a subject of controversy.  The
contents of the  abdomen, for  instance,  were
described as being constantly  moistened by a
very thin watery fluid.  The same thing takes
place in the pericardium, pleura, and all the 
              Of the Abdomen.          283

other cavities of the body, and this watery flu-
id is the lymph.  But whether it is exhaled into
those cavities through the minute ends of arte-
ries, or transuded through their coats, are the
points in dispute.  We cannot here be permit-
ted to relate  the many ingenious arguments
that have been advanced in  favour of each of
these opinions ; nor is it  perhaps of  conse-
quence to our present purpose to enter into the
dispute.   It will be sufficient if the reader can
form  an idea of what the lymph is, and of the
manner in which it is absorbed.
  The lymph, from its transparency and want
of colour, would seem to be nothing but wa-
ter; and hence the first discoverers of these
vessels styled them ductus aquosi: but experi-
ments prove, that the lymph of an healthy ani-
mal coagulates by being exposed to the air,
or a certain degree of heat, and likewise by be-
ing suffered to rest.; seeming to  agree  in this
property with,that partof the blood  called the
coagulable lymph.—This property 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, l>y its gela-
tinous 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,hy
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 ba-
son of water, is enabled to attract the water into
it to a certain height; but it is probable that they 
284          Of the Abdomen.

likewise possess a living power, which assists
in performing this office.   In  the human body
the lymph, or the chyle, is  probably 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, whether
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
towards the thoracic duct; these vessels have
probably a muscular coat,  which may serve to
press the fluid forwards from one pair of valves
to another ; and as the large lymphatic vessels
and the thoracic duct  are  placed close  to  the
large arteries,  which have a considerable pul-
sation, it is reasonable to  suppose,  that they
derive some advantages from this situation.


 Sect. XV.    Of the  Generative Organs;  of
               Conception,  he.

           J. 1.  The Male  Organs.

   The male organs of generation have been
usually divided  into the parts which serve to
prepare 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 expelling  parts,  which are  the  different
offices of the testes, the vesicula seminales, and
the penis ; and this is the Order in which  we
propose to describe them. 
Of the Abdomen.           285
   The testes are two glandular bodies, serving
to secrete the semen  from  the blood.   They
are originally formed  and lodged within the ca-
vity 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.*   By this disposition
they  are very wisely  protected from the inju-
ries to which  they would be liable  to be  ex-
posed, from the different positions of the child
at the time  of parturition.
   The  testicles in  this  state  are loosely at-
tached to the  psoae  muscles, by means  of the
peritonaeum by  which they  are  covered; and
they  are  at this time of life  connected in  a
very particular manner to  the parietes  of the
abdomen,  and  likewise  to  the  scrotum,  by
means of a substance which Mr. Hunter calls
the ligament or gubernaculum testis,  because  it
connects the  testis with the  scrotum, and di-
rects its course in  its  descent.   This guber-

  * It sometimes happens in  dissecting  ruptures,  that the intes-
tine is found in the same sac, and  in contact with the testis.
This appearance was at  first  attributed  to a supposed laceration
of the  peritonaeum ; but later observations, by pointing out the
situation of the testicles in the foetus,  have led  to prove, that
the testis, as it  descends into the scrotum, carries with it a por-
tion or elongation  of the peritonaeum, 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 communica-
tion between this sac and the cavity of the abdomen, is usually
soon cut off; but in some subjects it continues open during life;
and when an hernia or descent of the intestine takes place in such
a subject, it does not  push down a portion  of the peritonaeum
before it, as it must otherwise necessarily do, but  passes at once
through this opening, and comes in contact with the .naked tes-
ticle, constituting that particular species of rupture called hernia
congenita. 
 286          Of the Abdomen.

 naculum is of a pyramidal form, with its bul-
 bous head fixed to the  lower end of the testis
 and epididymis, and loses its  lower and slen-
 der extremity in the cellular membrane  of the
 scrotum.   It is difficult  to ascertain what the
 structure and composition of this gubernacu-
 lum is, but it is certainly vascular and fibrous;
 and, from certain circumstances, it would seem
 to be in part composed of the  cremaster mus-
 cle, running 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 common hernial  sac.  We have
 already observed, that  during its residence in
 the cavity of the abdomen it is  attached  to the
 peritonaeum, which descends with it;  so that
 when the sac is completed in the scrotum, the
 testicle is at first attached only to the posterior
 part of it, while the fore  part of it lies loose,
 and for  some time  affords a  communication
 with  the  abdomen.  The  spermatic chord,
 which is made up of the spermatic 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 perito-
 naeum-   But the fore part of the peritoneal
 sac, which is at first loose and  not attacfied to
 the testicle, closes  after a certain time, and
becomes united to the posterior part, and thus
 perfectly surrounds the testicle as it were in
 a purse.
  The testicles of the foetus differ only in their
 size and situation from those of the adult.  In 
Of the Abdomen.           287
their passage from the abdomen they descend
through the abdominal rings into the scrotum,
where they are supported and defended by va-
rious integuments.
   What the  immediate  cause  of this descent
is,  has not yet been satisfactorily determined.
It has been  ascribed to the effects of respira-
tion,  but  the testicles  have sometimes  been
found in the  scrotum  before  the  child  has
breathed;  and  it does not seem to  be occasi-
oned 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 ab-
domen 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 ex-
ternally divided into two equal parts by a pro-
minent  line called raphe.
   In the inner part  of  the scrotum we meet
with a cellular  coat called dartos,*  which by
its  duplicature divides the scrotum into two
equal parts,  and forms  what is called septum
scroti,  which corresponds  with  the raphe.
The collapsion which is  so  often observed to
take place  in the scrotum of the healthy  sub-
ject, when excited by cold or by the stimulus
of venery,  seems to be very properly attribute

  * The dartos has usually been considered as a muscle,  and h
described as such both by Douglas and Winslow.  But 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 merelv as a  cellular coat. 
288           Of the Abdomen.
ed to the contractile motion  of the skin, and
not to any muscular fibres, as is the case in
dogs and some other quadrupeds.
  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 securely lodged and  separated from each
other.   These coats are the  cremaster,  the
tunica vaginalis,  and  the  tunica albuginea.
The first of  these  is  composed of muscular
fibres, and  is to be considered only as a par-
tial covering  of the testis; for it surrounds
only the  spermatic chord, and terminates upon
the upper and external parts of the tunica va-
ginalis testis,  serving to  draw up and suspend
the testicle.*   The tunica vaginalis testis has
already been  described as being a thin  pro-
duction of the  peritonaeum,  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 glistening appearance, which immediate-
ly invests the body of the testis and the epidi-
dymus;  serving in some measure to connect
them to  each other, but  without  extending
itself at all to the spermatic chord.  This tu-
nica albuginea serves  to confine the growth
of the testis  and  epididymus  within certain
limits, and  by giving  them a  due  degree  of
firmness, enables them  to perform their pro-
per functions.

  * 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 insen-
sibly lost upon the tunica vaginalis of the testicle.  It 9erves to
suspend and draw up the testicle. 
              Of the Abdomen.           289

  Having removed this last tunic, we disco-
ver the substance of the testicle itself, which
appears to be made up  of an infinite  number
of very elastic filaments, which may  be best
distinguished after  macerating  the testicle in
water.  Each testicle is made up of the  sper-
matic artery and vein, and the  excretory ves-
sels or tubuli seminiferi.  There  are  likewise
a great number of absorbent vessels, and some
branches of nerves  to be met with in the tes-
ticles.
  The spermatic arteries  arise one  on  each
side from the aorta, generally  about an inch
below the  emulgents.   The right spermatic
vein commonly passes into the vena cava; but
the left  spermatic  vein usually empties itself
into the emulgent  on that side; and  it is sup-
posed to take  this  course  into the emulgent,
that it may avoid passing over the aorta, which
it would be obliged 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 tubuli  seminiferi are seen running in
short waves from  the  tunica albuginea  to the
axis of the testicle ;  and are divided  into dis-
tinct portions by certain thin membranous pro-
ductions, which originate from the tunica  al-
buginea.   They at length unite, and  by  an
infinite number of convolutions form  a sort of
                    Oo 
29U            Of the  Abdomen.
appendix to the testis called epididymis,* which
is a vascular body  of an oblong shape,  situate
upon the superior part of each testicle.  These
tubuli  of the epididymis at length form an ex-
cretory  duct  called  vas  deferens, which  as-
cends  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
deposite its semen in  the vesiculae  seminales,
which  are two soft bodies of a white and con-
voluted  appearance   externally,  situated  ob-
liquely  between   the  rectum  and  the  lower
part of  the bladder,  and uniting together at
the lower extremity.    From these reservoirs,f


   *  The testicles were named didymi by the  ancients,  and the
name of  this part was given to it on account of its situation upon
the testicle.
   ■f  That the bags  called vesicula seminales are reservoirs of se-
men, is a circumstance which has been by anatomists universal-
ly believed. Mr. J. Hunter, however, from several circumstan-
ces, has been induced to think this opinion erroneous.
   He has examined these  vesiculae in people who have died sud-
denly, and he found their  contents to be different in their proper-
ties from the semen.  In those who had lost one of the testicles,
or the use  of one of them,  by disease, both  the vesiculae  were
full, and their contents similar.  And in a lusus  nature, where
there was no communication between the vasa deferentia and ve-
siculae, nor between the vesiculae 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  testi-
cle and in the epididymis, and that the vesiculae 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 secret-
ed, and  kept there till  it is used; but that it  is secreted at the
time, in consequence of certain affections of the mind stimulat-
ing the testicles to this action.
   He corroborates his observations by the appearance on dissec-
tion in other animals;  and  here he finds, That the shape and 
Of the Abdomen.             291
which  are plentifully supplied  with blood-ves-
sels and nerves,  the  semen is occasionally  dis-
charged through  two  short  passages, which
open into  the  urethra close to a little eminence
called  verumontanum.


contents  of the vesiculae 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  vesiculae:  That the contents of the vesiculae 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 ob-
serves 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
fairly drawn: That the bags called vesiculx seminales are not se-
minal 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 vesiculae
do not contain the semen, he has not been able to ascertain their
particular use.  He thinks, however,  we may be allowed  upon
the whole to conclude, that they are,  together with other parts,
subservient to the purposes of generation.
  Although the author has treated this subject very ably, and
made many ingenious observations, some things may be object-
ed to what he has advanced ; of which the following  are a few i
That those animals who have bags called  vesiculae seminales per-
form 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 communication between the vasa
deferentia and vesiculae ; and in animals  where the  author has
observed no communication between the vasa deferentia and ve-
siculae, there may be a communication by vessels not yet disco-
vered, and which may be compared  to the hepato-cystk ducts
in fowls and fishes : That the fluid in the end of the va$a defe-
rentia and the vesiculae seminales are similar, according to the
author's  own observation.:  That the  vesiculae  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
reservoir for the semen.
  With respect to  the circumstance of the bulb of the urethra
answering tire purpose of a reservoir,  the  author has mentioned
no facts which tend to establish this  opinion.  See Observations
on certain Parts of the Animal  Occonomy. 
292           Of the  Abdomen.
  Near this eminence we meet with the pros-
tate, which is situated at the neck of the blad-
der, and is described as being of a  glandular
structure.  It is shaped somewhat like a heart
with its  small end foremost, and  invests the
origin of the urethra.   Internally it appears to
be of a firm substance, and composed of seve-
ral  follicles,  secreting  a  whitish viscid  fluid,
that is discharged by ten or twelve excretory
ducts into the urethra,  on each  side of the
openings of the vesiculae 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  vesiculae seminales
of the dead subject, it probably owes its white-
ness and viscidity to this liquor of the  pros-
tate.
  The penis, which is  to  be considered as
the vehicle  or active organ of procreation, is
composed of two columns,  the corpora caver-
nosa, and corpus  spongiosum.  The  corpora
cavernosa, which  constitute the greatest part
of the penis,  may be described as two cylin-
drical  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 capable  of considerable
distention; and being united laterally  to each
other,  occasion  by this  union a space above
and another below.  The uppermost 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 separat- 
Of the Abdomen.           293
ed  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 diminish-
ing gradually in size, are  attached,  one  on
each  side, by means of the ligamentum sus-
pensorium penis to  the ramus  ischii, and to
the inferior portion of the os pubis.
  The  corpus  spongiosum penis, or corpus
spongiosum urethrae, as it is  styled  by some
autnors, begins  as  soon as the urethra has
passed the prostate,  with a thick origin almost
like a heart,  first under the urethra, and af-
terwards  above it,  becoming gradually thin-
ner, and surrounding the whole canal of the
urethra, till it terminates in a considerable ex-
pansion, and  constitutes  what  is  called the
glans penis, which is exceedingly vascular, and
covered with  papillae  like the  tongue.  The
cuticle which lines the inner surface of the ure-
thra,  is continued over the glans in the same
manner as it is spread over the lips.
  The penis  is invested by the  common inte-
guments, 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 prepuce  is tied down to  the under part
of the glans by a small ligament catted franum,
which is in fact only a continuation of the cu-
ticle and cutis.  There are  many simple seba-
ceous   follicles   called  glandula  odorifera,
placed  round  the basis of the glans ;  and the
fluid they secrete serves to preserve the exqui- 
294            Of the Abdomen.
site sensibility of this part of the penis,  and to
prevent the ill effects of attrition from the pre-
puce.
   The urethra  may be defined to be a mem-
branous  canal,  passing  from  the bladder
through the whole extent of the penis,   Seve-
ral very small openings,  called lacuna, com-
municate with this canal,  through which a mu-
cus is discharged into, it; and besides these,
there are two glands, first described by Cow-
per, as secreting  a fluid  for  lubricating  the
urethra, and called Cowper's glatids ;* and
Littref 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  observed is occasionally discharged into
it  from the  vesiculae  seminales.   The  direc-
tion of this  canal being first  under and then
before the pubis, occasions a winding  in its
course from the bladder to the  penis not unlike
the turns of the letter S.
   The penis  has  three pair of muscles,  the
erectores,  acceleratores,  and transversales.
They push the blood from the crura to the fore
part of the corpora cavernosa.   The first origi-
nate from the tuberosity of the ischium, and
terminate in the corpora cavernosa.   The ac-
celeratores arise from  the sphincter,  and by

  * Both Hefster and Morgagni observe,  that they have some-
times not been able to find these glands: so that they do not
seem to exist in all subjects.
  f Memoires de 1' Acad. Royale des Sciences, 1700. 
Of the Abdomen.           295
their insertion serve to compress the bulbous
part of the urethra; and the transversales are
destined to afford a passage to the semen, by
dilating the canal of the urethra.
   The arteries of the penis are chiefly deriv-
ed from the internal iliacs.   Some of them are
supposed to  terminate by pabulous  orifices
within the corpora cavernosa and corpus spon-
giosum ; and others terminate in veins, which
at last make up the vena  magna dorsi penis,
and  other smaller  veins, which are in general
distributed in like  order with the arteries.
   Its nerves  are large  and numerous.  They
arise 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 explain-
ed,  how it is enabled to attain  that degree of
firmness and distention  which is essential to
the great work of generation.
   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 directions.   Now, the blood is
constantly passing into its  cells through the
small branches of the arteries which open into
them, and is  from  thence as constantly return-
ed by the veins, so long as the corpora caver-
nosa and corpus spongiosum 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, ejaculatores  seminis, le- 
296            Of the  Abdomen.
vatores ani, he. are induced to contract, the
veins undergo  a certain  degree of compres-
sion,  and the passage of the blood  through
them is  so much  impeded, that it collects 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 for-
cibly drawn up against the os pubis, the vena
magna itself is  at length compressed, and the
penis becomes fully  distended.   But as the
causes  which first occasioned this distention
subside, the penis gradually returns to its state
of relaxation.

     J. 2.  Female Organs of Generation.

   Anatomical writers visually divide the fe-
male organs of generation into external and in-
ternal.   In the first division they include the
mons veneris, labia pudendi, perinaum, clito-
ris,  nympha, and caruncula 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 inter-
nally composed of adipose membranes,  which
makes  it soft and prominent:  it  divides into
two parts called labia pudendi, which descend-
ing towards the rectum, from which they are
divided by the perinaeum, form  what is called
the fourchette.  The perinaeum  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. 
              Of the  Abdomen.          297

  The labia pudendi  being separated, we ob-
serve a sulcus called fossa magna;  in the up-
per part of which is placed the clitoris, a small
round spongy  body, in  some measure resem-
bling the  male  penis,  but  impervious,  com-
posed of two  corpora  cavernosa, arising  from
the tuberosities  of the  ossa ischii; furnished
with two pair  of muscles, the erectores clito-
ridis, and the sphincter  or constrictor ostii va-
ginae ; and terminating  in a glans,  which is
covered with  its prepuce.  From  the lower
part, on each side of the fossa, pass the nym-
phae, two membranous and spongy folds which
seem destined for useful purposes in parturi-
tion, by tending to enlarge the volume of the
vagina as the child's head passes through it.
Between these, about die middle of the fossa
magna,  we perceive the  orifice of the vagina or
os externum,  closed  by folds  and wrinkles;
and about half an inch  above  this,  and about
an inch below the clitoris, appears the meatus
urinarius or orifice of the urethra, much short-
er, though somewhat larger,  than in   men,
with a little  prominence at its lower  edge,
which  facilitates  the  introduction of the ca-
theter.
  The os externum is  surrounded internally
by several membranous  folds called caruncula
myrtiformes, 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 appear-
ance ; sometimes, however,  it has been found
perfectly closed.
                     pP 
298           Of the Abdomen.

  The vagina, situated between the urethra
and the rectum, is a membranous cavity, sur-
rounded  especially at its external  extremity
with a spongy and vascular substance,  which
is  covered by the sphincter ostii vaginx.   It
terminates in  the  uterus, about half an inch
above  the os tincae, and is wider  and shorter
in women who have had children  than  in vir-
gins.
   All these parts are plentifully supplied with
blood-vessels and nerves.   Around the nym-
phae 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 mucus, which defends it against
the acrimony of the  urine.
   The uterus is a  hollow  viscus, situated in
the hypogastric region, between  the rectum
and bladder.  It is destined to receive the first
rudiments of the  foetus, and to assist in the
developement of all its parts, till it arrives at
a state of perfection, and is fitted to enter into
the world, at  the  time appointed by the wise
Author of nature.
   The uterus, in its unimpregnated state, re-
sembles  a pear in shape, somewhat flattened,
with its fundus or bottom part turned towards
the abdomen, and its cervix or neck surround-
ed by the vagina.   The entrance  into  its ca-
vity forms a  little  protuberance,  which has
been compared to the mouth of a tench, and
is therefore called os tinea.
   The substance  of the uterus, which is of a
considerable  thickness, appears  to be com- 
Of the Abdomen.          299
posed of muscular and small ligamentous fi-
bres,  small  branches  of  nerves,  some  lym-
phatics, and with arteries and veins innumera-
ble.   Its nerves are chiefly derived from the
intercostal, and its arteries and veins from the
hypogastric  and  spermatic.  The  membrane
which lines its cervix, is a continuation of the
inner membrane of the vagina;  but the outer
surface of the body of the uterus  is covered
with the peritonaeum, which  is reflected over
it, and descends from thence to the  intestinum
rectum.  This duplicature of the peritonaeum,
by passing off from the sides of the uterus to
the sides  of the  pelvis,  is there firmly con-
nected, 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
within the fore-part of the ligamenta lata, de-
scend through  the  abdominal rings, and ter-
minate in  the  substance of the mons veneris.
The substance of these ligaments is vascular,
and although 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 pregnancy they admit of consider-
able distention, and after parturition return
nearly to  their original state with  surprising
quickness.
  On each  side  of the inner surface of the
uterus, in the angle near  the fundus,  a small
orifice is to be discovered, which is the begin-
ning of one of the tubae Fallopianse.  Each of 
300
Of the Abdomen.
these tubes, which are two in number, passing
through the substance of the uterus, is extend-
ed along the broad ligaments, till it reaches the
edge of  the  pelvis, from  whence it reflects
back; and turning 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 fimbria, or morsus diaboli.   Each tuba
Fallopiana is usually about three or four inches
long.  Their cavities  are at first very small,
but  become  gradually larger,  like a trumpet,
as they approach the fimbriae.
   Near the  fimbriae 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 covered by a production of the peritonaeum,
and hangs loose in  the pelvis.   They are of a
flat and angular form, and  appear to be com-
posed  of a white  and cellular substance, in
which we  are able  to discover  several  minute
vesicles filled with  a coagulable lymph, of an
uncertain number,  commonly exceeding  12 in
each ovary.   In the  female  of riper  years,
these vesicles become exceedingly turgid, and
a kind of yellow coagulum is gradually formed
within one of them, which increases for a cer-
tain time.  In conception, 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 yellow colour,  and is therefore
called corpus luteum; and it is observable, that 
Of the Abdomen.            301
the number of these  scars  or fissures in the
ovarium, constantly corresponds with the num-
ber of foetuses excluded by the mother.


            q. 3. Of Conception.

   Man,  being ever curious and  inquisitive,
has naturally been led to inquire 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 mi-
nute recesses, the philosopher soon finds him-
self bewildered, and his imagination often sup-
plies that which he so eagerly wishes to disco-
ver, 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 considered the male semen
as alone capable of forming the foetus, and be-
lieved that the female only afforded it a lodging
in the womb, and supplied it with nourishment
after it  was perfectly  formed.  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 foetus
as being formed by the  mixture  of the semi-
nal liquor of both sexes,  by a certain arrange-
ment of its several particles in  the uterus.
But in the 16th century, vesicles or eggs were
discovered in the ovaria or female testicles ;
the foetus had been  found sometimes in the ab-
domen, and sometimes in the Fallopian tubes ; 
 302          Of the Abdomen.

 and the two former opinions were exploded  in
 favour of a new doctrine.   The ovaria were
 compared to a bunch of grapes, being suppos-
 ed to consist of vesicles,  each of which had a
 stalk ; so that it might be disengaged without
 hurting  the rest, or spilling the liquor it con-
 tained.   Each vesicle was said to include a lit-
 tle animal, almost complete in all its parts ; and
 the vapour of the male semen being conveyed
 to the ovarium, was supposed to produce  a fer-
 mentation in  the vesicle, which approached
 the nearest to  maturity;  and thus 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 mo-
 ther and the foetus.
    This opinion, with all its absurdities, con-
 tinued to be almost  universally adopted till the
 close  of the same  century,  when  Lieuwen-
 hoeck, 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 explod-
 ed.  According to this theory the male semen
passing into the tubae Fallopianae, one of the
animalcula penetrates into the substance of the
ovarium, and enters into one of its vesicles or
ova.  This impregnated ovum is then squeez- 
              Of the  Abdomen.           303

ed from its husk, through the coats of the ova-
rium, and being seized by the fimbriae, is con-
ducted through the lube to the uterus, where
it is nourished till it arrives at a state of per-
fection.  In this system there is much ingenu-
ity ; but there are certain circumstances sup-
posed to take place, which have been hitherto
inexplicable.  A celebrated modern writer, M.
Buffon, endeavours to restore,  in  some mea-
sure, the most ancient opinion, by allowing the
female semen a share in this  office ; asserting,
that animalcula or organic particles  are to be
discovered in the seminal liquor 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  evidently  mista-
ken ; and  the  opinion  now most  generally
adopted is, that an impregnation of the ovum,
by the influence of the male semen, is essential
to conception.*   That the ovum is  to be im-
pregnated, there can be no doubt;  but as the
manner in which such an impregnation is sup-
posed to take place, and the means by which the
ovum afterwards gets into the Fallopian tube,
and from thence into the uterus, are still found-
ed chiefly  on hypothesis, we will not attempt
to extend farther the investigation  of a sub-
ject concerning which so little can be advanc-
ed with certainty.

  * The learned Abbe Spallan/.ani has thrown much  light on
this curious subject, and has proved by a variety of experiments,
that the animalcule exists entire in the female ovum and that the
male seed is only necessary to vivify and pit it in motion.—His
experiments and observations  are worthy the attentive perusal of
every physiologist. 
,304           Of the Abdomen,
         \. 4.  Of the Foetus in Utero.

   Opportunities of dissecting the  human
gravid uterus occurring but seldom, the state
of the embryo* 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 ascertain-
ed.
   About the third or fourth week the eye may
discover the first lineaments of the foetus ; but
these  lineaments are as  yet  very imperfect,
it  being only  about  the  size of a house-fly.
Two little vessels appear in an almost transpa-
rent jelly ; the largest  of which is destined to
become the head of the foetus,  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 does not as 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 dis-
cover 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 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 /ictus. 
              Of the Abdomen.          305

the trunk, both above and below,  we see four
minute protuberances, which are the rudiments
of the arms and legs.   At the end of eight
weeks the body of the foetus is upwards of an
inch in length, and both the hands and feet are
to be distinguished.   The upper extremities
are found to increase faster than the lower ones,
and the  separation of the fingers is accomplish-
ed sooner than that of the  toes.
   At this period the human form may be de-
cisively  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 foetus
measures 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 fifteen inches ; and  at the end  of the ninth
month, or full time, from eighteen to twenty-
two inches.   But as we have not  an opportu-
nity of examining the same foetus 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  foetus 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
                   Qq 
306            Of the  Abdomen.
seems likely, that the posture of some of these
parts is varied in the latter months of pregnan-
cy, so as to cause those painful twitches which
its mother usually feels from time to time.   In
natural  cases, its head is  probably  placed to-
wards the os tincse from the time of conception
to that of its birth; though formerly it was con-
sidered as being placed towards the fundus ute-
ri till about the eighth or  ninth month,  when
the  head,  by becoming  specifically  heavier
than the  other parts of the body, was supposed
to be turned downwards.
  The capacity of the uterus increases in pro-
portion to the growth of the foetus, but with-
out becoming thinner in its substance, as might
naturally be  expected.   The nourishment of
the foetus, during all this time,  seems to be de-
rived from  the placenta, which appears  to be
originally formed by that part of  the ovum
which is next the fundus uteri.   The remain-
ing part  of the  ovum  is  covered by a mem-
brane called spongy  chorion \* within which is
another called true chorion, which includes  a
third termed amnios ;f this contains a watery

  * Tit. Hunter has described this as a lamella from the inner
surface of the uterus.   In the latter months of pregnancy it be-
comes gradually thinner and more connected with the chorion :
he has named it membrana caduca, or decidua, as it is cast off with
the placenta. Signior Scarpa, with more probability, considers
it as being composed of an inspissated coagulable lymph.
  f In some quadrupeds, the urine appears to be conveyed from
the bladder  through a canal called urachus to the allantois, which
is a reservoir, resembling a long and blind gut, situated between
the chorion  and amnios. The human foetus  seems to have no
such reservoir,  though fome writers have supposed that  it does
exist.  From the top of the bladder a few longitudinal fibres are
extended to the umbilical chord ; and these fibres have been con-
sidered as the urachus, though without having been ever found
pervious. 
Of the  Abdomen.           307
fluid  which is the liquor amnii,*  in which the
foetus floats till the time of its birth.   On the
side next the foetus, the placenta is covered by
the amnios and true chorion; on the side next
the mother it has a production continued from
the spongy chorion.   The amnios and chorion
are remarkably thin  and  transparent,  having
no  blood-vessels  entering into their composi-
tion.   The spongy chorion is opake and vas-
cular.
  In  the first months of pregnancy,  the involu-
cra bear  a large proportion  to their contents ;
but this  proportion is afterwards reversed,  as
the foetus increases in bulk.
  The placenta, which is  the medium through
which the blood is conveyed from the  mother
to  the  foetus, and the manner in  which this
conveyance takes place,  deserve next  to  be
considered.
   The placenta  is a broad, flat,  and  spongy
substance,  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  ramifications of the umbilical  arteries
and vein, and partly of the extremities of the
uterine  vessels.   The  arteries of  the  uterus
discharge their contents into the  substance of

   * The liquor amnii coagulates like the lymph.  It has been
supposed to pass into the oesophagus,  and to afford nourishment
to the foetus; but this does  not feem probable.  Children  have
come into the world without an oesophagus or any communica-
tion between the stomach and the mouth ; but there has been no
well attested instance of a child's having been born without a pla-
centa ; and it does not seem likely,  that  any of the fluid can be
absorbed through the pores of the skin, the skin in the foetus be-
ing  every where covered with a great quantity of mucus. 
 308           Of the Abdomen.

 this cake ; and the veins of the  placenta, re-
 ceiving  the blood either by a direct communi-
 cation of vessels, or by absorption, at length
 form the umbilical  vein,  which  passes on to
 the sinus of the vena portse, and  from  thence
 to the vena cava, by means of the  canalis veno-
 sus, a  communication that is  closed  in  the
 adult.  But the circulation of the blood through
 the heart is not conducted  in the foetus as  in
 the adult: in the latter, the  blood is  carried
 from the right auricle of the heart through 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, how-
 ever, is  supplied in the foetus by the immedi-
 ate communication between the right and left
 auricle, 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,  gra-
 dually closes after birth.
  The blood is returned again from the foetus
 through  two arteries  called the  umbilical arte-
 ries, 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  um-
bilical  chord.   These  arteries, after ramifying
through  the  substance  of the  placenta,  dis-
charge their blood into the veins of the uterus; 
 
\\.\T  <>\l Y
X
he,  t
v V^/O^
u  +
^^
l'|..lr\\\
t^j lr
,/>«+, PM,,(. 
              Of the  Abdomen.          309

in the same manner as the uterine arteries dis-
charged their blood into  the branches of the
umbilical vein.   So that the blood is constant-
ly passing in at one side  of the placenta and
out at the other; but in what particular man-
ner it gets through the placenta is a point not
yet  determined.
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 windpipe.  2 2,
The internal jugular veins.   3 3, 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.   12 12, The anterior edge of the
diaphragm.   13 13, The two  great lobes of
the liver.  14, The ligamentum rotundum. 15,
The gall-bladder.   16,  The  stomach.   17 17,
The jejunum and  ilium.  18, The spleen. 
310           Of the  Abdomen.
Fig. 2. Shows the Organs subservient of the
  Chylopoietic Viscera,—with  those of Urine
  and Generation.

  1  1, 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.   6 6, The
kidneys.    7, The aorta descendens.   8, Ve-
na cava ascendens.  9 9, The  renal veins co-
vering the arteries.   10,  A  probe under the
spermatic vessels and a bit of the inferior me-
senteric  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.

   A A,  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, Ductus communis cho-
ledochus.  G,  Venaportarum.  H, Arteria hep-
atica. I I, The stomach. K K, Venae and arte-
riae gastro-epiploicae, dextrae h  sinistra.  L L,
Venae & arteriae coronariae ventriculi.   M, The
spleen.   N N,  Mesocolon,  with its  vessels.
OOO,  Intestinum colon.    P, One of the li-
gaments  of the colon, which is a bundle of
longitudinal muscular fibres.   Q.QQ.Q, Jeju- 
Of the Abdomen.           511
num and ilium.   R R,  Sigmoid flexure of the
colon with the ligament continued, and over S,
The rectum intestinum.   T T, Levatores ani.
U, Sphincter ani.  V, The place  to which the
prostate  gland is connected.   W,  The anus.


Fig. 4.  Shows  the  Heart of a Foetus  at the
  full  time,  with the Right Auricle  cut open
  to show the Foramen Ovale, or passage be-
  tween both Auricles.

  a, The right ventricle,   b, The  left ventri-
cle,    c c, 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,  with the  membrane  or valve
which covers the left side,   f, Vena cava in-
ferior passing through g,  A portion of the dia-
phragm.


Fig.  5.  Shows the Heart and Large  Vessels
          of a Foetus at the full time.

  a, The left ventricle,   b,  The right ventri-
cle,   c,  A part of the right auricle.   d,  Left
auricle,   e e, The right branch of the  pulmo-
nary artery,   f, Arteria pulmonalis.   g g, The
left  branch  of  the pulmonary artery,  with a
number  of its largest branches dissected from
the lungs,  h,  The canalis arteriosus,  i, The
arch of the aorta,  kk, The aorta descendens.
1, The left subclavian artery,   m, The left ca-
rotid artery,   n, The right carotid artery,  o,
The  right subclavian artery,   p,  The origin 
312          Of the Abdomen,
of the right carotid arid right subclavian arteries
in one common trunk,   q,  The vena cava su-
perior or descendens.   r,  The right common
subclavian vein.    s, The  left  common  sub-
clavian vein.
  N. B.   All the parts described in this figure
are to be found in the adult, except the cana-
lis arteriosus.
            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.
E, E, F, Branches of the  crural artery.  G,
The musculus gastrocnemius.   IT, The tibia.
I,  The tendon of the musculus tibialis anticus.
On the  out-lines, a, A lymphatic vessel be-
longing to the  top of the foot,  b, Its first di-
vision into branches.   c, c, c,  Other divisions
of the same lymphatic  vessel.    d,  A  small
lymphatic gland.  e, The lymphatic vessels
which lie between the skin and the muscles  of
the thigh,  f,  f, Two lymphat^ 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 with-
out communicating with them ; and, bending
towards the inside of the groin at (i), opens
into the lymphatic gland (k).   1,1,  Lympha-
tic glands  in the groin,  which are common to
the lymphatic  vessels of the genitals and those 
\ 
V 
Of the Abdomen,
313
of the lower extremity.    m, n,  A plexus of
lymphatic vessels passing on the inside of the
iliac artery.


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.  F F, The
two cut surfaces of the triceps  muscle, which
was divided to show the lymphatic vessels that
pass through its perforation along with the cru-
ral artery.  G, The edge of the musculus gra-
cilis. H, The gastrocnemius and  soleus, much
shrunk by being dried, and by the soleus be-
ing separated from  the tibia to expose the ves-
sels.   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  posterior tibial artery,  a,
A lymphatic vessel accompanying the posterior
tibial artery,  b,  The same vessel crossing the
artery,   c, A small lymphatic gland,  through
which this deep-seated lymphatic vessel passes.
d, The lymphatic vessel passing under a small
part of the soleus, which is left attached to the
bone, the rest being removed.   e, The lym-
phatic vessel crossing the  popliteal artery,  f,
g, h, Lymphatic glands in the ham,  through
                    R r 
314            Of the Abdomen.
which  the lymphatic vessel passes,  i, The
lymphatic vessel passing with the crural  ar-
tery, through  the  perforation of the triceps
muscle,   k, The lymphatic vessel, after it has
passed the perforation of the triceps, dividing
into branches  which embrace the artery  (1).
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 superficial lym-
phatic  vessels,   n,  A part of the superficial
lymphatic vessel appearing on the brim of the
pelvis.


Fig. 3. Exhibits the  Trunk of  the  Human
   Subject,  prepared to  show  the Lymphatic
   Vessels and the  Ductus Thoracicus.

   A, The neck. B B, The two jugular veins.
C,  The vena cava superior.  D D D I>, The
subclavian  veins.   E, The  beginning of  the
aorta,  pulled to the left side by means of a li-
gature, in order to show the thoracic duct be-
hind it.   F, The branches  arising from  the
curvature of the aorta.  G G, The two caro-
tid arteries. H H,  The first ribs.  I I, The
trachea.  K K, The spine.  L L,  The vena
azygos.   M M, The descending aorta.  N,
Ttie coeliac artery,  dividing into three branch-
es.  O,  The superior mesenteric artery.   P,
The right  crus diaphragmatis.   Q Q, The
two kidneys.  R,  The right emulgent artery.
S S, The external iliac  arteries,  g d, The
musculi psoae.  T, The internal  iliac  artery. 
Of the Abdomen.           315
<U, The cavity of the pelvis.  X X, The spine
of the os ilium.  Y Y, The groins,  a,  A lym-
phatic gland in the groin,  into which lympha-
tic vessels from the lower  extremity are seen
to enter,   b b, The lymphatic  vessels of  the
lower extremities passing  under Poupart's li-
gament,  c c, A plexus  of the lymphatic ves-
sels 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
pelvis,  and received the  lymphatic vessels  be-
longing to the viscera contained in that  cavity,
next  ascends, and  passes  behind the iliac ar-
tery to (g).  f,  Some lymphatic vessels of the
left side passing over the upper part of the os
sacrum, to meet those of the right side, g, The
right psoas, with a large plexus of lymphatics
lying on its inside,   h h, The plexus lying, on
each side of the spine.   Hi,  Spaces occupied
by the lymphatic glands,   k, The  trunk of  the
lacteals, lying on the under side of  the supe-
rior mesenteric artery.   /,  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 thoracic duct beginning from the large
lymphatics,  n, The duct passing under  the
lower part of the crus diaphragmatis, and un-
der the right emulgent artery,  o, The thora-
cic duct penetrating the thorax,  p, Some lym-
phatic vessels joining that duct in the thorax-
q, The thoracic duct passing under the  curva-
ture of the aorta to get to the left subclavian 
316            Of the  Abdomen.
vein.   The aorta being drawn  aside to show
the duct,  r, A plexus of lymphatic vessels
passing upon the trachea from  the thyroid
gland to the thoracic duct.
           Plate  XXVII.

Fig. 1.  Represents the Under and Posterior
      Side of the Bladder of Urine, he.

  a, The bladder,  b b, The insertion of the
ureters,  c c, The vasa deferentia,  which con-
vey the semen from the testicles to d d,  The
vesiculae seminales,—and pass through e, The
prostate  gland, to discharge themselves into
f, The beginning of the urethra.


  Fig. 2. A transverse Section of the Penis.

  g g, Corpora cavernosa  penis,  h, Corpus
cavernosum urethrae.  i, Urethra,  k, Septum
penis.   1 1, The septum between  the  corpus
cavernosum urethrae and that of the penis.


 Fig. 3.  A longitudinal Section of the Penis.

  m m, The corpora cavernosa penis, divided
by o,  The septum  penis,  n, The  corpus ca-
vernosum glandis, which is the continuation of
that of the urethra. 
VA'a'

X
X/
fr* 
 
Of the Abdomen.           3i7
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
into the cavity of the uterus;—but the other
end is open within the pelvis, and surrounded
by  c c, The fimbriae,  d d, The ovaria.  e, The
os  internum  uteri,  or mouth of the  womb.
f f, The  ligamenta  rotunda,  which  passes
without the belly,  and is fixed to the labia pu-
dendi.   g g,  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
(1,) The praeputium.   m m, The labia puden-
di.   n n, The nymphae.


Fig. 5.   Shews the Spermatic  Ducts  of the
        Testicle filled with Mercury.

  A, The vas deferens.  B, Its  beginning,
which forms  the posterior  part of the epididy-
mis.  B, The middle of  the epididymis,  com-
posed of serpentine ducts.  D, The head or
anterior  part  of  the epididymis unravelled.
e e e e, The whole  ducts which compose the
head of the epididymis unravelled,  f f, The
vasa deferentia.   g g, Rete testis,  h h, Some
rectilineal ducts which send  off the vasa defe-
rentia.   i i,  The  substance of the testicle. 
318            Of the  Thorax.
Fig. 6.  The right Testicle  entire,  and the
       Epididymis filled with Mercury.

  A, The beginning of the vas deferens.   B,
The  vas  deferens  ascending  towards  the
abdomen. C, The posterior part of the epididy-
mis, named globus minor.  D, The  sperma-
tic  vessels inclosed in cellular substance.   E,
The  body of the epididymis.  F, Its head,
named globus  major'  G, Its  beginning  from
the  testicle.  H,  The body  of the testicle,
inclosed in the tunica albuginea.
PART  IV. OF THE THORAX.
    THE  thorax,  or  chest, is that cavity of
     the trunk which extends from the clavi-
cles, 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 trachea
and oesophagus.—This cavity-is formed by the
ribs and vertebras 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 up by muscular fibres, which
from their situation are called intercostal mus-
cles. 
Qf the Thorax.             319
          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 veinsevery where accompany the arteries
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
approach the nipple, form  the tubuli lactiferi,
which are usually more than a dozen in num-
ber, and open at its apex, but have little or no
communication,  as has been supposed, at the
root of the nipple.  These ducts, in their course
from the glands, are surrounded by a ligamen-
tary elastic substance, which  terminates with
them  in the nipple.  Both this substance, and
the ducts which it contains, are capable of consi-
derable extension and contraction ; but in their
natural state are moderately corrugated, so as to
prevent an involuntary flow of milk, unless the
distending force be very  great from the accu-
mulation of too great a quantity. 
 320            Of the Thorax.

   The whole  substance of the nipple is very
 spongy and elastic : its external surface is un-
 even, 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 very thin ; and the nervous papillae 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
 secretion  begins  to take place soon after de-
 livery, and continues to flow for many months
 in very large quantities, if the woman suckles
 her child.
   The  operation  of suction depends  on  the
 principles  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 gene-
 rality of physiologists have supposed that, like
 the chyle,  it frequently retains the properties
 of the  aliment  and medicines taken into the
 stomach ; 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 lined
by a membrane of a firm texture called pleura.
It is composed of two distinct portions or bags,
             * Journ. de Med. 1781. 
Of the Thorax.            321
which, by being applied to each other laterally,
form a septum called mediastinum ; which di-
vides the cavity into two parts, and is attached
posteriorly  to  the vertebrae  of the back, and
anteriorly to the sternum. But the two laminae
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 lodgment to the heart; and at the upper part
of the cavity, they receive between them the
thymus.
   The pleura  is  plentifully supplied  with
arteries and veins from  the  internal mammary
and  the intercostals.   Its nerves,  which  are
very inconsiderable, are derived chiefly from
the dorsal and intercostal nerves.
   The surface of the pleura, like that of the pe-
ritonaeum and other membranes lining cavities,
is constantly bedewed with a serous  moisture*
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 com-
pressing  each other when we lie on  one side;
and consequently contributes to the freedom of
respiration, which  is  disturbed  by  the  least
pressure on the lungs.   If the point of a sword
penetrates between the ribs into the cavity of
the thorax, the lungs on that side cease to per-
form their  office ; because  the  air  being ad-
                      S s

  * When this fluid is exhaled in too great a quantity, or U
not properly carried off, it accumulates and  constitutes the hy-
drops pectoris. 
322
Of the Thorax.
 mitted through the wound,  prevents the dila-
 tation of that lobe ; while the other lobe, which
 is separatedfromitby the mediastinum, remains
 unhurt,  and continues 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
 excretory duct not having yet been discovered.
 It is  of an oblong figure, and is larger in the
 foetus and in young  children than in adults,
 being sometimes nearly  effaced in very old
 subjects.   It is  placed in  the  upper part of
 the thorax,  between  the  two  laminae 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 abdomen,  by a  fleshy  and  mem-
 branous  substance called  the diaphragm or
 midriff.  The greatest part of it is composed
 of muscular  fibres; and  on this account sys-
 tematic  writers usually place it very properly
 among the muscles.  Its  middle part is tendi-
 nous, and it is covered by  the pleura above,
 and by the peritonaeum below.  It seems to
have  been improperly named septum transver-
sum, as it does not make a plane transverse di- 
Of the  Thorax.            323
vision of the two cavities, but forms a kind of
vault, the fore-part of which is attached 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
vertebrae lumborum, where  it may be  said to
be divided into two  portions or crura.*
  The principal  arteries of the diaphragm are
derived from the aorta, and  its veins pass into
the vena cava.   Its nerves  are chiefly derived
from the cervical pairs.  It affords a passage
to the vena cava through its tendinous part,
and to the oesophagus through its fleshy portion.
Xhe aorta passes down behind  it between its
crura.
   The diaphragm not only serves to divide
the thorax from  the abdomen, but by its mus-
cular  structure is  rendered one  of the chief
agents in respiration.  When  its fibres con-
tract, its  convex side, which is turned towards
the thorax, becomes gradually flat, and by in-
creasing the cavity of the breast, affords room
for a complete dilatation of the lungs, by means
of  the  air  which is  then drawn  into them
by the act of inspiration.   The fibres of the di-
aphragm then relax; and as it resumes its for-
mer state, the cavity of the thorax becomes  gra-
dually diminished,  and the air is driven out
again from the lungs by a motion contrary to the
former one, called exspiration.

  * Anatomical writers have usually described the diaphragm
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
vertebras. 
324           Of the Thorax.

  It is in some measure, by means of the dia-
phragm, that we void the faeces at the anus, and
empty the urinary bladder.   Besides these offi-
ces,  the acts of coughing,  sneezing, speaking,
laughing, gaping,  and sighing, could not take
place without its  assistance ; and the  gentle
pressure which all the  abdominal viscera re-
ceive from its constant and regular motion, can-
not fail to assist in the performance of the se-
veral 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 described.   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  shaped  like a buck-
ler ;  and the other  cricoides 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 po- 
                Of the  Thorax.            325

mum 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
motion 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 produces no sound.
   These cartilages  are moistened by  a mucus
which  seems to be secreted by minute glands
situated near them.   The  upper  part of the
trachea is covered anteriorly and laterally by a
considerable body,  which is supposed to be of
a  glandular structure,  and  from its  situation
near  the thyroid 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  aspera  arteria,  and  extends  from
thence as far down as the third or fourth verte-
bra of the  back,  where  it divides into  two
branches  which are the  right and left  bron-
chial tube.   Each of these  bronchi* ramifies

  * The right  bronchial tube is usually found to be somewhat
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, obferves  that  the left bronchial tube  is closely
connected by the a uta ;  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.  Mcmoins de I' A:ad:mu
Roy ale des Sciences, 1769. 
326           Of the  Thorax.
through the substance of that lobe of the lungs
to which  it  is  distributed, by  an  infinite
number of branches, which are formed of car-
tilages 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
gradually less and  less in their diameter, the
lower ones are  in some  measure received into
those above them, when the lungs, after being
inflated,  gradually  collapse by the  air being
pushed out from them in exspiration.  As the
branches of the bronchi become more  minute,
their cartilages  become more and more  angular
and membranous, till at length they are found
to be perfectly membranous, and at last become
invisible.
  The  trachea is  furnished with fleshy or
muscular 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
fibres, 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
ramifications, are furnished with a great num-
ber 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 respir-
ing ; and its membranous part, by being capable 
Of the Thorax.            327
of contraction and dilatation, enables us to re-
ceive and expel the air in a greater or less quan-
tity, and with more or less velocity, as may be
required in singing or  in declamation.  This
membranous structure  of the trachea poste-
riorly,  seems likewise to assist in the  descent
of the food, by preventing that impediment to
its passage down the oesophagus,  which might
be expected if the cartilages  were complete
rings.
  The  trachea  receives its arteries from the
carotid  and subclavian  arteries, and its veins
pass into the jugulars.   Its nerves arise from
the recurrent 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
texture, and are divided into two  lobes, which
are separated from each  other  by the  me-
diastinum,   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
minute, 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. 
328           Of the Thorax.
  The lungs seem to possess but little sensibili-
ty.   Their nerves, which are small and few in
number, 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 reas-
cends at the back part of the trachea, to which
it furnishes branches in its ascent,  as  well as
to the oesophagus, 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 arterise bron-
chiales, and the pulmonary artery.
  The  arteriae bronchiales begin usually by
two branches;  one of which  commonly arises
fr<. m the right intercostal,  and the other from
the trunk of the aorta:  but  sometimes there
are three of these arteries, and in  some sub-
jects only one.   The use of these arteries is  to
serve for  the nourishment 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 bron-
chial 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 de-
stined 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
pulmonary artery receives the blood from the
right ventricle of the heart, and dividing into 
              Of the  Thorax.           329

two branches, accompanies the bronchi every
where,  by its ramifications through the lungs;
and the blood is afterwards conveyed back by
the pulmonary vein, which gradually forming
a considerable 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 proportion of time  through all tfye
other parts of the body.


         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
alternate contraction and dilatation of the tho-
rax,  by first inspiring air  into the lungs,  and
then expelling it from them in  exspiration.
   It will perhaps  be easy to  distinguish  and
point out the several  phenomena of respira-
tion ;  but to explain their physical cause  will
be attended with  difficulty,  for it will natural-
ly be  inquired,  how the lungs, when  emptied
of the air, and contracted by  exspiration, be-
come  again inflated, they  themselves  being
perfectly passive ? How the ribs are  elevated
in opposition to  their own  natural situation  ?
and why the diaphragm  is contracted  down-
wards towards the abdomen ?  Were we to as-
sert that the  air, by forcing its  way  into the
cavity of the lungs, dilated them,  and  conse-
quently elevated  the ribs, and pressed down
                    T t 
330
Of the Thorax.
the diaphragm, we should  speak erroneously.
What induces  the  first  inspiration, it is not
easy to ascertain ; but after an animal has once
respired, it would seem likely that the blood,
after exspiration, finding its passage through
the lungs  obstructed,  becomes a  stimulus,
which induces the intercostal muscles and the
diaphragm to contract, and enlarge the cavity
of the thorax,  in  consequence  perhaps  of a
certain nervous influence,  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 pul-
monary vessels being equally distended, the
blood flows through them with ease.  But as
the stimulus which first occasioned this dilata-
tion ceases to operate, the muscles  gradually
contract, the diaphragm rises upwards again,
and diminishes  the  cavity of the chest; the
ribs return to  their former state ; and as the
air passes out in exspiration, the lungs gradu-
ally 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 begins again to be distend-
ed, the stimulus is renewed, and  the same
process is repeated, and continues  to be re-
peated,  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 
Of the Thorax.            331
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
stimulus to inspiration.  In drowning, the cir-
culation seems to be stopped upon this  prin-
ciple ;  and in  hanging, the pressure made  on
the  jugular 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 respira-
tion.  It was at  length discovered in part  by
the  illustrious  Dr. Priestley.  He found that
the  air exspired by  animals  was phlogistica-
ted ; and that the air was fitter for respiration,
or for  supporting animal life, in  proportion as
it was freer from the phlogistic  principle.  It
had long been observed, that the blood in pas-
sing through the lungs acquired  a  more florid
colour.  He  therefore  suspected, that it was
owing to its having imparted phlogiston to the
air: and he  satisfied himself of the truth of
this idea, by experiments, which showed, that
the crassamentum of  extravasated blood,  phlo-
gisticated air  in  proportion as it lost its dark
colour.  He  farther  found, that blood  thus
reddened had a  strong attraction for phlogis-
ton ; insomuch that it was capable of taking it
from phlogisticated air,  thereby becoming of
a darker colour.  From hence it appeared that
the blood,  in its  circulation through the  arte-
rial  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. Craw* 
332           Of the Thorax.
ford and Mr. Elliot.   It had been shown by
professors Black and Irvine, that different bo-
dies have different  capacities for  containing
fire.  For example,  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 tem-
peratures.   The  inquiries of  Dr.  Crawford
and Mr. Elliot tend to prove, that the capaci-
ties of bodies for containing fire are diminish-
ed by the addition of phlogiston, and  increas-
ed by its separation:  the capacity  of calx of
antimony,   for  example, being greater  than
that of the  antimony itself.  Common air con-
tains a  great quantity  of fire ; combustible bo-
dies very little.  In combustion, a double elec-
tive attraction takes place ;  the phlogiston 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 increas-
ed so much as that of the former is diminish-
ed, only part of the extricated  fire will be ab-
sorbed by  the body.   The remainder there-
fore  will raise the  temperature of the  com-
pound ; and hence we  may account for the heat
attending combustion.   As the use of respira-
tion  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 
Of the Thorax.           333
through the body, imbibes phlogiston, and of
course gives out its fire ; part only of which is
absorbed by the parts furnishing the phlogis-
ton,  the remainder, as in combustion, becom-
ing 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 render-
ed, by combination with phlogiston, less fit for
respiration.*
  In ascending very high mountains, respira-
tion is found to  become short and  frequent,
and  sometimes to be  attended with a spitting
of blood.   These symptoms  seem to  be  occa-
sioned by the air  being too  rare  and thin to
dilate  the  lungs sufficiently; and the blood
gradually accumulating in the pulmonary ves-
sels, sometimes bursts through their coats, and
is brought up by coughing.   This has likewise
been accounted for in a different way,  by sup-
posing that the air contained 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-
pump, are seen to swell as  the outer air be-
comes  exhausted.   But Dr.  Darwin of Litch-
  * See Crawford's Experiments and Observations on Animal
Heat, and Elliot's Philosophical Observations. 
334           Of the Thorax.
field 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 spitting of blood, which  has
sometimes taken place in ascending high moun-
tains, 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  many  times
greater  than  on the  summit of the  highest
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 hautboy, to an organ,  he. 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 dilating like  bellows during the time of
inspiration; and as the air is driven out from
them in exspiration, it finds  its passage strait-
ened  by the cartilages of the larynx, against
which it  strikes.   As these cartilages are more
or less elastic, they occasion in their turn more
or less vibration in the air, and  thus produce 
              Of the  Thorax.           335

the sound  of the  voice; the variation in the
sound and  tone of which depends on the state
of the glottis, which, when straitened, pro-
duces 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 string, as
well as a  wind, instrument; so that what art
has hitherto   been unable  to construct, and
what both  the fathers  Mersenne and Kircher
so much wished 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  hori-
zontally across it, which are capable of consi-
derable vibration,  so as to produce sound, in
the same  manner  as  it  is  produced by the
strings of  a  violin  or  a  harpsichord: 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 regu-
late  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 distention or  relaxation  of  these strings,
the sound being more or less acute in propor-
tion as they  are more or less  stretched  out.
Another  writer on this subject supposes,  that
the organ  of voice is a double  instrument,
which produces in unison two sounds of a dif-
ferent nature; one by means of the  air, and
the other by  means of the chords of the glot- 
336           Of the Thorax!.
tis.  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
satisfactorily  ascertained:  we  may observe,
however, that the sound produced by the glottis
is  not articulated.   To effect this, it is  requir-
ed to pass through the mouth, where it is dif-
ferently modified by the action of the tongue,
which  is  either pushed against  the teeth, or
upwards towards ihe palate ; detaining it in its
passage, or permitting it to flow freely, by con-
tracting-or dilating the mouth.


          Sect. IX.   Of Dejection.

   By dejection we mean the act of voiding the
faeces 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 require a knowledge of respiration to  be
perfectly understood.
   The intestines were described as having a
peristaltic motion, by  which  the  faeces  were
gradually  advancing towards the anus.   Now,
whenever the faeces are accumulated  in the
intestinum rectum  in a sufficient  quantity to
become troublesome,  either by their weight or
acrimony, they excite  a  certain  uneasiness
which  induces us  to go to stool.—To effect
this, we begin by making a considerable  in-
spiration ; in  consequence  of which the dia-
phragm is carried downwards towards the low-
er belly;  the  abdominal muscles  are  at the 
               Of the  Thorax.           337

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 faeces  pass  out  at  the anus;
which is afterwards drawn up by its longitu-
dinal fibres, which are called levatores ani, and
then by  means of  its  sphincter  is again con-
tracted : but it sometimes happens,  as in  dy-
senteries for instance, that the faeces are very
liquid, and have  considerable acrimony; and
then the irritation they occasion is more fre-
quent, so as to promote their discharge with-
out any pressure  from the diaphragm or  ab-
dominal muscles ; and sometimes involuntari-
ly,  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 medias-
tinum, recede one from the other, so as to af-
ford a lodgment to a firm membranous sac, in
which  the heart is  securely lodged; this sac,
which is the pericardium, appears to  be com-
posed of two  tunics, united to each other by
cellular membrane.—The outer coat, which
is thick,  and in some places  of tendinous com-
plexion,  is a production of the  mediastinum  ;
the inner coat, which is extremely thin, is re-
flected over the auricles and ventricles of the
heart, in the  same  manner as the tunica con-
                    U u 
338           Of the Thorax.
junctiva, 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;
arid 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 contain it loosely. As its  cavity does not
extend to  the sternum, the  lungs cover it in
inspiration ; and  as  it every where invests the
heart,  it effectually  secures it from  being in-
jured by lymph,  pus, or  any other fluid, ex-
travasated into the cavities of the thorax.
   The heart is  a hollow muscle of a conical
shape,  situated transversely between the two
laminae of the mediastinum, at the lower  part
of the  thorax ; having its basis turned towards
the right side, and  its point or apex towards
the left,—Its lower  surface is somewhat flat-
tened towards the diaphragm.  Its basis, from
which the great  vessels originate, is covered
with fat, and it has  two hollow and  fleshy ap-
pendages,  called  auricles.—Round these seve-
ral openings, the heart seems to be of a firm
ligamentous texture, from  which all its fibres
seem to originate ;   and as they advance from 
Of the Thorax.           339
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 per-
haps, with respect to their situation,  it would
be more  proper  to distinguish them  into the
anterior and posterior ventricles.
   The heart  is exteriorly covered  by a very
fine membrane ;  and its structure is perfectly
muscular or  fleshy,  being composed of fibres
which are described as passing in different di-
rections ;  some  as being  extended longitudi-
nally 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.*
—Within the two ventricles we  observe  seve-
ral furrows;  and there are likewise tendinous
strings, which arise from fleshy columna in the
two cavities,  and are attached to the valves  of
th6>^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  membranous
production, which is attached all round to the
borders of their several orifices, from whence
hanging loosely down they appear to be divid-
ed into two or three distinct  portions.  But  as

  * 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. 
340
Of the Thorax.
their uses in the arteries and veins are differ-
ent, so are they  differently disposed.  Those
of the arteries are intended to give way to the
passage of the blood into  them from the ven-
tricles, but to oppose its  return:  and, on the
contrary,  the valves of the veins are construct-
ed  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 ar-
tery 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  toge-
ther, 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 valvula semilunares.  The com-
munication between the two  great veins and
the ventricles is  by means  of the two appen-
dages or auricles into which the blood  is dis-
charged ;  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  valvula tri-
cuspides ;  but in the left ventricle we common-
ly observe only two, and these are the valvula
mitrales.  The  membranes which form these
valves in each cavity are attached so as to pro-
ject somewhat  forward; and  both the  tricus-
pides and the mitrales  are connected with the
tendinous strings, which   were  described   as
arising from the fleshy columna.   By the con- 
Of the Thorax.           341
traction of either ventricle, the blood is driv-
en into the artery which  communicates v.ith
that  ventricle;  and  these tendinous  strings
being gradually relaxed as the sides of the ca-
vity  are brought  nearer  to  each  other,  the
valves naturally close the opening into the au-
ricle, 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 ventricle, from
whence, by another contraction,  it  is again
thrown into the artery, as will be described
hereafter.  The right ventricle is not  quite so
long, though  somewhat larger, than  the left;
but  the  latter has  more  substance than  the
other: and this seems to  be, because it is in-
tended to transmit  the  blood to the most  dis-
tant  parts of the body, whereas the right ven-
tricle distributes it  only to the lungs.
   The heart receives its nerves from the  par
vagum  and  the intercostals.  The  arteries
which serve for its nourishment  are two in
number, and arise from the aorta.   They sur-
round in some measure  the basis of the heart,
and  from  this course are called the  coronary
arteries.   From these arteries the  blood is re-
turned by  veins of the same name into the au-
ricles, and even into the ventricles.
   The  muscular bags called the  auricles are
situated at the basis of the heart,  at the sides
of each other;  and, corresponding with  the
two  ventricles, are like those two cavities  dis- 
342             Of the  Thorax.
tinguished  into right and left.  These sacs,
which are interiorly unequal, have externally
a jagged appendix;  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 ven-
tricles  into the pulmonary artery  and the aor-
ta,  and then as relaxing itself and receiving a
fresh supply from two large  veins, which 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 sub-
divided into  an infinite number of branches and
ramifications,  which extend through the whole
substance of the lungs ; and from these branch-
es the blood is returned by  the veins, which,
contrary to  the  course of the arteries, begin
by very minute canals,  and  gradually  become
larger,  forming at  length four  large trunks
called pulmonary 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 
Of the Thorax.            343
an  inch in diameter; it  soon sends  off two
branches,  the coronaries,  which  go to be dis-
tributed to the  heart and its auricles.   After
this,  at  or about the third or fourth  vertebra
of the  back,  it makes  a  considerable curva-
ture ; from this curvature * arise three arte-
ries; one of Which soon divides into two branch-
es.   The  first two are  the  left subclavian
and the left  carotid, and the  third is a com-
mon  trunk to the right subclavian and right
carotid  ; though sometimes  both the carotids
arise distinctly from the aorta.
  The  two carotids ascend within the subcla-
vian,  along  the sides of  the trachea; and
when they have reached the larynx,  divide
into two principal branches, the internal and
external carotid.  The first of these runs a lit-
tle way backwards in a bending direction ; and
having  reached the under part of the ear, pass-
es  through the canal into  the os petrosum,
and entering  into the cavity of the cranium, is
distributed to the brain  and the membranes
which envelope it,  and likewise 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.

  *  Anatomists usually call the upper part of this curvature
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 curva-
ture. 
344            Of the Thorax.
   Each  subclavian is likewise divided  into  a
great number of branches.   It sends off the
vertebral  artery,  which passes  through  the
openings we see at the bottom of the transverse
processes of the vertebrae of the neck,  and in
its course sends off many ramifications to the
neighbouring parts.  Some of its branches are
distributed to the  spinal marrow, and after  a
considerable  inflection it enters into the crani-
um,  and is distributed to the brain.  The sub-
clavian likewise sends off branches to the mus-
cles  of the neck and scapula ;  and the medias-
tinum, thymus,  pericardium, diaphragm, the
breasts, and  the  muscles 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;  as the mammary, the
phrenic, the intercostal, he.  But notwithstand-
ing the great number of branches which have
been described as arising from the subclavian,
it  is  still  a considerable artery when it reach-
es the axilla, where it drops  its former name,
which alludes to its  passage under the clavi-
cle,  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 brachi-
alis, 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  two branch-
es.  This division however is different in dif-
ferent subjects ; for in some it takes place high-
er up and in others lower  down.   When  it
happens to divide above  the joint,  it may be 
               Of the Thorax,           345

considered as a happy disposition in case  of an
accident by bleeding; for supposing the artery
to be unfortunately punctured by the lancet,
and that the haemorrhage could only be  stop-
ped by making a ligature  on the vessel, one
branch  would remain unhurt, through which
the blood would pass uninterrupted to the fore-
arm and hand.   One of the two 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 sur-
face of the  radius,  and  is easily  felt at the
wrist, where it is only covered by the common
integuments.  Both these branches commonly
unite  in the  palm of the hand, and form an ar-
terial  arch from whence branches are detached
to the fingers.
   The aorta, after having given off at its cur-
vature the carotids and subclavians which con-
vey blood to  all the upper parts of the body,
descends upon the bocjies of the vertebrae a lit-
tle 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 bifurcation, it sends
off several arteries in the  following order:  1.
One or  two little arteries, first demonstrated
by Ruysch as going to the  bronchi, and called
arteria bronchinales Ruyschii.   2. The arteriae
oesophageae.   These are commonly three or
four in  number.  They  arise from  the  fore-
part of the aorta, and are distributed chiefly to
the oesophagus.   3.  The  inferior intercostal
arteries, which are distributed between the
ribs in the same manner as the arteries of the
                     X  x 
346           Of the  Thorax.

three or four superior  ribs are, which are  de-
rived 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, spleen, liver, and -gall-
bladder.  5. The coeliac,  which sends off  the
coronary-stomachic, the splenic, and the  hepa-
tic artery.   6. The superior mesenteric artery,
which is distributed to the mesentery and small
intestines,   7. The emulgents, which go to  the
kidneys.   8.  The  arteries,  which are distri-
buted to the glandulae renales.   9. The sper-
matic.   10. The inferior mesenteric artery,
which ramifies through the lower portion of the
mesentery and the large intestines.—A branch
of this artery which goes to the rectum is call*
ed the internal hamorrhoidal.  11. The lum-
bar arteries, and a  very  small branch called
the sacra, which are distributed  to the  mus-
cles  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
forked branches  called the iliacs.   Each of
these soon  divides into two branches; one of
which is called the  internal iliac,  or hypogas-
tric artery, and is distributed  upon the contents
of the pelvis and upon the muscles on its out-
er side.   One branch, called pudenda commu-
nis,  sends small ramifications to the end of
the rectum under the name of hamorrhoidales
externa,  and is afterwards  distributed  upon
the penis.   The other  branch, the external ili- 
             Of the  Thorax.            347

ac,  after having given off the circumflex artery
of the os ilium and  the epigastric, which is
distributed to the recti-muscles, passes out of
the abdomen under Poupart's ligament,  and
takes  the name of crural artery.  It descends
on the inner part of  the thigh close to the os
femoris,  sending  off branches to  the muscles,
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 di-
vides  into two branches, and these arteries all
go to  be  distributed 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 conti-
nued  from the ultimate  branches of arteries ;
and  uniting together as  they approach the
heart, at length form the large trunks,  the ve-
na 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 ascen-
dens .-, and these two eavas uniting together as
they approach 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  suffi-
cient to remark, that in  general every artery is
accompanied by its vein, and that both are dis-
tinguished by the same name.  But, like many 
548            Of the Thorax.
other general rules, this too has its  excep-
tions.*   The veins for instance, which  accom-
pany the external and internal carotid,  are not
called the carotid veins, but the external and in-
ternal jugular.—In the  thorax, there is a vein
distinguished by a proper name, and this is the
azygos, or vena sine pari.    This vein, which
is a pretty considerable one, runs along by the
right side of the  vertebrae of the back, and  is
chiefly destined 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 abdo-
men we meet with a vein, which is still a more
remarkable  one,  and this is the vena porta,
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 com-
pose one great trunk, which  goes  to  ramify
through the liver;  and after having deposited
the bile, its  ramifications  unite and bring back
into the vena cava,  not  only the  blood which
the vena portae 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 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 re-
moved from the source and cause  of  its mo-

  *  Tn the extremities, some of the deep-seated veins, and all
the superficial  ones, take a course different from that of the
arteries. 
Of the Thorax.            349
tion, which are in the heart, than it was when
in the arteries ;  so that its course is consequent-
ly less rapid, and enough of it could not pos-
sibly be brought back to the heart in the mo-
ment  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 conti-
nuance of life  and health would consequently
be destroyed,  if the capacity of the veins did
not exceed that of the arteries, in the same pro-
portion that the rapidity 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 inone 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 in-
to one of the trunks and returning through the
other, we shall be enabled to conceive how the
blood 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 eve-
ry trunk seems to contain less  blood than the
many branches do into  which that trunk sepa-
rates  ; and each of these  branches probably 
350           Of the Thorax.
 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
 muscles,  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 form-
 ed 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 as-
 cendens, we meet with only one valve, which
 is near its origin.
  The arteries are composed of several tunics.
 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
the arteries; but as they do not seem to be ir-
ritable, we cannot with propriety suppose them
to have a muscular tunic.  We are  aware of
Dr. Verschuir's* experiments to prove  that
the jugular  and some other  veins possess  a
* De Arteriarum et Venarum vi irritabili, 4to. 
Of the Thorax.           351
 certain degree of  irritability; but it is  cer-
 tain, that his experiments, repeated by others,
 have produced 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 mi-
 nute 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 circulates 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
 becomes relaxed to receive more blood from
 the auricles; so that the cause of the contrac-
 tion 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 effects
 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
 constant  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  occasioned by the  motion of the  dia-
phragm, and by the regurgitation of the blood
in the cavas. 
3 52           Of the Thorax.
   Sect. XII.   Of the Action  of the Heart,
            Auricles, 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 ar-
teries, are distinguished by the  names of systole
and diastole.   When the heart is in a state of
contraction or systole, the arteries are at that
instant  distended with  blood, and in  their
diastole ; and 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 returned back to the heart.
While the heart, however, 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  auricles contract, and
drive the blood into the ventricles ; so that the
auricles have an alternate systole  and diastole
as  well as the  heart.
   Although both the ventricles  of the heart
contract at  the same time,  yet the blood pass-
es  from one  to the other.   In  the same mo-
ment,  for  instance,  that  the left  ventricle
drives  the blood into the aorta, the right ven-
tricle  impels  it  into  the  pulmonary  artery, 
               Of the Thorax.            353

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  ail
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 quantity  and heat,  or other properties,* 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 prin-
ciple  of irritability,  in a much greater degree
than any other muscle of the body.  The pulse
is quicker in young than in old subjects,  be-
cause  the former are cat. par. more irritable
than the latter.   Upon the same principle we
may explain, why the pulse is constantly quick-
er in weak than in robust persons.
                  Y y

  * Dr. Harvey long ago suggested, that the blood is possessed
of a living principle ; and Mr. J. Hunter has lately endeavoured
to revive this doctrine : in support of which he has adduced many
ingenious arguments.  The subject is a curious one, and deferves
to be prosecuted as an inquiry which cannot but be interesting
to physiologists. 
354           Of the Thorax*
      Sect.  XIII.  Of  the Circulation.

  After   what  has been observed  of the
structure  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 demonstrate the circulation  of the
blood, which has long since been established
as a medical  truth.-  This circulation may be
defined to be a perpetual motion of the  blood,
in consequence of the action 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-
duced 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
considerably  between   the  ligature  and the
heart; whereas if we tie up a vein, it only be-
comes filled between  the extremity and the
ligature, and this is what we every day observe
in bleeding.   The  ligature we pass round the
arm on these occasions, compresses the super-
ficial veins;  and  the return of the   blood
through them being impeded, they become dis-
tended.   When the ligature is too loose, the
veins are not sufficiently  compressed, and the
blood continues its  progress towards the heart;
and, on the contrary, when it is made too tight,
the  arteries  themselves become compressed ; 
               Of the  Thorax.           355

and the flow of the blood through them being
impeded, the veins cannot be distended-
   Another phaenomenon,  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 con-
tinues to flow from the wounded vessel till the
equilibrium is  destroyed which is essential to
life.   This truth was not unknown to the an-
cients ;  and it  seems  strange that  it  did not
lead, them to a knowledge of the circulation, as
it sufficiently proves, that all the other vessels
must  communicate with that which is opened.
Galen,  who lived more  than 1500 years ago,
drew  this  conclusion  from it; and if we far-
ther observe, that he describes (after Erasis-
tratus, who flourished  about 450 years before
him)  the several valves  of the  heart, and de-
termines their disposition and uses, it will ap-
pear wonderful, that  a  period  of  near  2Q00
years should afterwards elapse  before the true
course of the  blood was ascertained.   This
discovery,  for  which we are indebted to the
immortal Harvey, has thrown new lights on
physiology and the doctrine of diseases, and
constitutes  one of the  most important 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 
356            Of the Thorax.

of a red colour ;* but when suffered to rest, it
Soon coagulaies, and divides into  two  parts,
which are distinguished by the  names of cras-
samentum and serum.    The crassamentum is
the red coagulum, and the  serum is the  water
in which it floats.   Each of these may be again
separated into two others;  for the  crassamen-
tum, by  being repeatedly washed in warm wa-
ter, gives out all its red globules, and  what
remains  appears to be composed of the coagu-
lable 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 limpid 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 great-
er  proportion  to the  serum  than  in a weak
one ;$ and the same difference is found to take
place in  diseases.J

  * The blood, as it flows through the arteries,  is observed to
be more florid than it is in the veins ; and this redness is acquir-
ed in its passage through the lungs.  Vid. feet. vii.
  f It may not be improper to observe, that till of late the coa-
gulable lymph has been confounded  with the serum of the^ blood,
which  contains  a substance that is likewise coagulable, 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.
  $ When the blood separates into strum and crassamentum, 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 
Of the  Thorax.            357
          Sect. XV.   Of Nutrition.

   The variety of functions which we have de-
scribed as being incessantly performed by the
living 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, he. are excluded
by stool.  But  the solid,  as well as the  fluid
parts of the body,  require a constant renewal
of nutritious particles.   They  are exposed to
the attrition of the fluids  which are circulated
through them;  and the contraction and relax-
ation they  repeat  so  many thousand times in
every day,  would necessarily occasion a disso-
lution 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

theory which ascribes the cause of inflammation to lentor and ob-
structions. But from the late Mr. Hewson's experiments it ap-
pears, that when the action of the arteries is increased, the blood,
instead of being more viscid, is, on the contrary, more fluid than
in the ordinary state, previous to inflammation ;  and that in con-
sequence of this, the coagulable lymph suffers the red globules,
which are the heaviest part of the blood, to fall down to the bot-
tom before it coagulates ; so that the crassamentum is  divided
into two parts: one of which is found to consist of the coagula-
ble lymph alone (in this case termed the buff) ;  and the other,
partly of this and partly of the red globules. 
358
Of the Thorax.
of 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
deposited by the arteries by exsudation through
their pores into the tela celluloa; 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,  he. are
sometimes  reduced again  by disease to a gela-
tinous state;  we  may, with some degree of
probability, consider the coagulable lymph as
the source of nutrition.
   If the supply of nourishment  exceeds the
degree of waste, the body increases; and  this
happens in infancy and in youth : for  at those
periods,  but more particularly  the former one,
the fluids bear a large proportion to the solids ;
and the fibres being soft and yielding,  are pro-
portionably more capable of extension and in-
crease.   But when the supply of nutrition only
equals the waste,  we neither increase nor de-
crease ; 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 firmness  and rigidity, do not permit
a farther increase of the body.   But as we ap-
proach to old age,  rigidity begins to be in ex-
cess, and the fluids * bear a much less propor-

  * As the fluids become less in proportion to the solids, their
acrimony is found  to increase ; and this may perhaps compen-
sate for the want of fluidity in the  blood by diminishing its co-
hesion. 
               Of the  Thorax.           359

tion to the solids than before.  The dissipation
of the body is greater than the supply of nour-
ishment ;  many of the  smaller vessels  become
gradually impervious ;* and the  fibres losing
their moisture and their elasticity, appear flac-
cid  and wrinkled.  The lilies and the roses dis-
appear, 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 im-
paired.


  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 seems more proper to distinguish three
kinds of glands, viz. the mucous,  conglobate,
and conglomerate.
  The mucous glands,  or follicles,  as they are
most  commonly called, are  small cylindrical

  *  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 capacity of the ve-
nous system exceeds that of the arteries and the lymphatic sys-
tem  almost disappear:-. 
360           Of the  Thorax,
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 together in  one common covering, and
opening into one common sinus.  These folli-
cles  are the vessels that secrete and pour out
mucus in the mouth,  oesophagus,  stomach,  in-
testines,  and other parts of the body.
  The conglobate  glands  are peculiar to  the
lymphatic system.  Every lymphatic vein pass-
es through a gland of this kind in its way to
the thoracic duct.  They  are met with in dif-
ferent 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  great-
er bulk than the conglobate, and seem to be an
assemblage of many smaller glands.  Of this
kind are  the liver, kidneys, he.  Some of them,
as the pancreas, parotids, he. have a granu-
lated appearance.   All these  conglomerate
glands are plentifully supplied with blood-ves-
sels ; but their nerves are in general very mi-
nute, and few in number.   Each  little granu-
lated portion  furnishes a small tube, which
unites with other  similar 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, 
              Of the Thorax.           361

its adherents.  One of these systems was ad-
vanced by Malpighi, who supposed that an ar-
tery entering into a gland  ramifies very mi-
nutely through its whole substance ;  and that
its branches ultimately terminate in a vesicu-
lar cavity or follicle,  from whence the secreted
fluid passes out  through the excretory duct.
This doctrine at first met with few opponents ;
but the celebrated Ruysch, who first  attempt-
ed minute injections with wax, afterwards dis-
puted the existence of these follicles,  and as-
serted, that every gland appears to be a con-
tinued series of vessels,  which after being re-
peatedly convoluted in their  course  through
its substance, at length terminate  in  the ex-
cretory duct.  Anatomists are still divided be-
tween 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
hypothetical.  In such an inquiry it is natural
to ask, how one gland  constantly separates a
particular  humour,  while another gland se-
cretes 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 particu-
lar 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 par-
ticular property.  So  that, according to this
system,  the blood,  as it circulates through the
                     Zz 
362
Of the Thorax.
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 confined in a place expos-
ed to  the  circulation, without  being carried
away  by the  torrent of blood,  every part of
which would be equally affected ; and this sys-
tem  of fermentation has long  been rejected as
vague and chimerical.   But as the cause of se-
cretion continued to be looked for in the fluids,
the former system was succeeded by another,
in which recourse was had to the analogy of
the humours.  It was observed, that  if paper
is moistened with water, and oil and water are
afterwards poured upon it, that the water only
will be permitted to pass  through it; but that,
on the other hand, if the  paper has been pre-
viously 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 furnish-
ed with a humour analogous to that which it is
afterwards destined to separate from the blood;
and that in consequence of this disposition, the
secretory vessels of the liver,  for instance,  will
only admit the bilious particles of the blood,
while all the  other humours will be excluded.
This system is an ingenious one, but the dif-
ficulties with which it abounds are  unanswer-
able ; for oil and water are immiscible ; where-
as the blood, as it is  circulated through the
body, appears  to  be an homogeneous fluid. 
Of the Thorax.            363
Every oil will pass through a paper moistened
only with one kind of oil;  and wine, or spirits
miAed 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 agree-
ing in that of  being perfectly miscible  with
each  other, will  all easily pass through the
same nitre.—But these  are not all the objec-
tions  to this system.  The humours which are
supposed to be placed in the secretory vessels
for the determination of similar particles of the
blood, must  be originally separated without
any analogous fluid;  and  that which happens
once, may as easily happen always.  Again,
it sometimes happens from a vicious disposi-
tion,  that humours are filtered through glands
which are  naturally not intended to afford
them a passage, and when this once has hap-
pened, 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 particular figure  of the secretory 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 differ-
ence  of diameter  in the orifices of the differ-
ent secretory vessels.  To this doctrine ob-
jections have likewise been raised; and it has
been argued, that the vessels of the liver, for
instance, would,  upon this principle,  aiiord a 
364
Of the Thorax.
passage not  only to the bile, but  to  all the
other humours ofless consistence with it.  In
reply to this objection, it has  been supposed,
that secondary 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
remote 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, he.

  Muscles, he.—Superior Extremity.—a,
Masseter.  b, Complexus.  c,  Digastricus. d,
Os  hyoides.  e,  Thyroid  gland,  f, Levator
scapulae,  g, Cucullaris.   h h," The clavicles
cut.   i, The deltoid  muscle,   k. Biceps flexor
cubiti cut.  . 1, Caraco-brachialis.   m, Triceps
extensor cubiti.   n, The heads of the pronator
teres, flexor carpi radialis, and flexor digito-
rum sublimis,  cut.   o, The flexor carpi ulna-
ris, cut at its extremity,   p, Flexor  digitorum
profundus,  q, Supinator  radii longus, cut at
its extremity,   r, Ligamentum carpi transver-
sale.   s, Extensores carpi radiales.   t, Latis-
simus dorsi.  u, Anterior  edge of the serratus
anticus major,  v v, The  inferior part of the
diaphragm,  w w, Its anterior edge  cut.   x x,
The kidneys,   y, Transversus abdominis,   z,
Os ilium. 
/ 
 
Of the Thorax.           365
   Inferior Extremity.—a,  Psoas magnus,
 b, Iliacus internus.  c, The fleshy origin of the
 tensor vaginae femoris.  d d, The ossa pubis
 cut from each other,   e, Musculus pectineus
 cut from its origin.  /, Short head of the tri-
 ceps abductor femoris cut.   g, The great head
 of the triceps,  h, The long head cut. i, Vas^
 tus internus.   k,  Vastus externus.   /, Crure-
 us.  m,  Gemellus,  n, Soleus.  o, Tibia.  py
 Peronaeus  longus.  q, Peronaeus  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.   G, The carotis externa.  H,
 Arteria  facialis,  which sends off the  coronary
 arteries of the lips.  I, Arteria temporalis pro-
 funda.   K, Aorta descendens.   L  L, The
 iliac arteries,—which  send off  M M, The fe-
 moral  or crural  arteries.  N.  B. The  other
 arteries  in  this figure have the same distri-
 bution as  the veins  of the same  name:—
 And generally, in the anatomical plates,  the
 description  to  be found on  the one side, points
 out the same  parts in the other.   1, The fron-
 tal vein.   2, The facial vein.   3, Vena tem-
poralis  profunda.   4, Vena occipitalis.   5,
Vena jugularis externa.   6, Vena  jugularis
interna,  covering  the  arteria carotis commu-
nis.   7.  The vascular arch on the palm of the
hand, which  is formed by,  8, The radial ar-
tery and vein, and,  9, The ulnar artery and 
366       Of the Brain and Nerves.

vein.   10  10, Cephalic vein.  11, Basilic vein,
that on the right side  cut.  12, Median vein.
13, The humeral  vein, which,  with  the  me-
dian,  covers the humeral artery.   14 14, The
external  thoracic  or  mammary  arteries  and
veins.   15, The axillary  vein,  covering  the
artery.  16 16,  The subclavian veins, which,
with (6 6) 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 ar-
tery,   21, The upper part of the vena saphena
major.  22, The femoral vein.  23 23, The
iliac veins. 24 24, Vena cava inferior.  25 25,
The renal veins covering the arteries.   26 26,
The diaphragmatic veins.
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
inclosing the brain, and defending it from ex-
ternal injury: but they are not its  only pro-
tection ; for when  we make an horizontal sec-
tion through these bones, we  find this mass 
Of the Brain and Nerves,        367
every wheyre surrounded by two membranes,*
the  dura  and pia mater.—The first of these
lines the  interior surface  of the cranium,  to
which it every where  adheres  strongly,! but
more  particularly at the  sutures, and at the
many foramina  through  which  vessels pass
between it  and the pericranium.  The  dura
mater t  is perfectly smooth and inelastic, and
its  inner surface is constantly bedewed with a
fine  pellucid fluid,  which every where  sepa-
rates 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 pro-
cess, from its  resemblance  to   a  scythe.   It
arises from the  spine  of the os frontis, near
the  crista 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

  * The Greeks called these membranes meninges ; but the Ara-
bians, supposing them to be the source of all the other mem-
branes of the body, afterwards gave them the names of dura and
pia mater ;  by which they are now usually distinguished.
  •j- In young subjects this adhesion is greater than in adults;
but even then, in the healthy subject, it is no where easily sepa-
rable, without breaking through some of the minute vessels by
means of which it is attached to the bone.
  £ This membrane is commonly described as consisting of two
laminae ; of which the external one is supposed to perform the of-
fice of periosteum internum to  the cranium, while the internal
one forms the folds and processes of the dura mater.  In the  na-
tural state, however, no such separation is apparent ; like other
membranes, we may indeed divide it, not into two only,  but
many laminae; but this division is artificial,  and depends on  the
dexterity of the anatomist. 
 568      Of the Brain and Nerves.

 suture, it divides  into two broad wings or ex-
 pansions called the transverse or lateral process-
 es, which prevents the lobes of the cerebrum
 from pressing on the  cerebellum.  Besides
 these there is a fourth, which is situated under
 the transverse processes, and being continued
 to the spine of the occiput, divides the cere-
 bellum into two lobes.
   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
 channels, situated behind these  several  pro-
 cesses.
   These canals or sinuses communicate  with
 each other, and empty themselves into  the in-
 ternal jugular veins, which convey the blood
 into the vena cava.   They are in fact triangu-
 lar veins, running through the substance of the
 dura mater, and,  like the processes, are dis-
 tinguished  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 supposed 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  enu-
 merate 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 inferior longitudinal sinus, the
superior a#d  inferior petrous sinuses, the ca- 
          Of the Brain and Nerves.      369

vernous  sinuses, the circular sinus, and  the
anterior and posterior occipital sinuses.
  These sinuses or veins,  by being conveyed
through  a thick dense membrane, firmly sus-
pended,  as the dura mater is, within the cra-
nium, are less  liable  to rupture ; at the same
time they 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
chorda  Willisii, from  their having been first
noticed by Willis) stretched across their cavi-
ties ; 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
membrane than the dura mater; being exceed-
ingly delicate, transparent, and vascular. It in-
vests every part of the brain, and sends off an
infinite number  of elongations, which  insinu-
ate  themselves  between the convolutions, and
even into the substance of the brain.  This
membrane is composed of two laminae ; of which
the exterior one is named tunica arachnoidea,
from its thinness, which is equal to that of a
spider's web.  These two laminae are intimate-
ly 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 uni-
                    3 A 
370       Of the Brain and Nerves.

formly over the surface of the brain, but with-
out entering into its furrows as the inner layer
does ;  the latter being found to insinuate itself
between the  convolutions, and  even  into the
interior cavities of the brain.  The blood-ves-
sels of the  brain are distributed through it in
their way to that organ, and  are therefore di-
vided  into very minute ramifications, before
they penetrate the substance of the brain.
  There are several parts included under the
general 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 infe-
rior and posterior part of the head, is the cere-
bellum ; and a  third, which  derives its origin
from both these, is the medulla oblongata.
  The cerebrum is  a medullary mass of a mo-
derate 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 distinguished into an interior, a mid-
dle, and a posterior lobe.  The first of these is
lodged on the orbital processes of the os fron-
tis : the middle lobes lie on the middle fossae of
the basis of the cranium,  and the  posterior
lobes are placed on the transverse septum of
the os occipitis, immediately over the cerebel-
lum, from which they are separated by the la-
teral processes of the dura mater.  These two
portions afford  no  distinguishing  mark of se-
paration ; and on this account Haller, and many
other modern anatomists,  omit the distinction 
          Of the Brain and Nerves.       371

 ei middle lobe, and speak only of the anterior
 and posterior lobes of the bra:n.
   The cerebrum appears to be composed of
 two distinct substances.   Of these,  the exte-
 rior 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 call-
 ed medulla or substantia alba.
   After having removed the falx,  and separat-
 ed the  two hemispheres from  each other, we
 perceive a white convex body, the corpus  cal-
 losum,  which is a portion of the medullary
 substance, uniting the  two  hemispheres  to
 each other,  and not invested by the cortex.
 By making an horizontal incision in the brain,
 on a level with this corpus callosum, we  dis-
 cover two oblong cavities,  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 separated laterally by a
 very fine medullary  partition,  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 corpus
 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 me-
 dullary substance, named commissiira anterior
 cerebri.   These crura diverging from one ano-
 ther, are  lost at the  outer side of the lower
and fore-part  of the third  ventricle.   Posteri-
orly  the fornix is formed into two other crura, 
372       Of the Brain and Nerves.

which unite with two medullary 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 covered by a medul-
lary lamina, called corpus fimbriatum.
   Neither the edges of the fornix, nor its pos-
terior crura, can be well distinguished, till we
have removed the plexus choroides.  This is
a production of the pia  mater,  which is spread
over the  lateral ventricles.   Its  loose edges
are collected,  so as to  appear  like a vascular
band on each  side.
   When we have  removed this plexus, we dis-
cover several  other protuberances included in
the lateral ventricles.   These are the corpora
striata,  the thalami nervorum opticorum,  the
tubercula  quadrumgemina,  and  the  pineal
gland.
   The  corpora striata  are two curved oblong
eminences, 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 substances of the brain. The thala-
mi nervorum opticorum, 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  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 
          Of the Brain and Nerves.      378

united,  and at their convex part  seem to be-
come one body.
  Anteriorly,  in the space between the thala-
mi, we observe an orifice by which the lateral
ventricles  communicate,  and  another leads
down from this, under the different appella-
tions oi foramen commune anterius, vulva iter
ad infundibulum, but more properly iter ad ter-
tium  ventriculum;  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 medul-
lary band, which connects the thalami to each
other, and is  called  commissiira posterior  ce-
rebri.
   Behind the thalami  and commissura poste-
rior,  we observe  a small, soft,  greyish, and
oval body, about the size of a pea.  This is
the glandula pinealis ;  it is described by Galen
under the name of conarion, and has been ren-
dered famous by Descartes,  who supposed it
to be the seat of the  soul.  Galen seems for-
merly to  have entertained the same opinion.
Some modern writers have, with as little rea-
son,  imagined  that  the  soul  is placed in the
corpus callosum.
   The  pineal gland rests upon four remarka-
ble eminences,  disposed in pairs,  and seated
immediately below it.  These tubercles, which
by the  ancients were  called testes and  nates,
have, since the time of Winslow,  been more
commonly named tubercula quadrugemina. 
374       Of the Brain and Nerves.

   Under the  thalami we  observe another ca-
vity,  the third ventricle, which terminates ai>
tenorly in a small medullary canal,  the infun-
dibulum, that leads to the glandula  pituitaria.
   It has  been doubted, whether the iufundi-
bulum is really hollow ;> but some late experi-
ments on this part of the brain * by  Professor
Murray  of Upsal, clearly prove it to be a me-
dullary canal, surrounded by both  laminae of
the pia mater.  After freezing the brain, this
channel   was  found filled with ice;  and  de
Haen tells f us,  he  found it dilated,  and filled
with  a calcareous matter.!
   The soft spongy body in which the infundi-
bulum terminates, was by  the  ancients  sup-
posed to be of a glandular structure, and des-
tined to  filter the serosity of the brain.   Spi-
gelius pretended to  have discovered its excre-
tory duct, but  it seems  certain that no such
duct exists.   It  is of an  oblong shape, com-
posed, as it were, of two  lobes.   In ruminant
animals it is much larger than in man.
   From  the posterior part of the third ventri-
cle, 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 ano-
ther cavity of the brain,  placed between the
cerebellum and medulla oblongata, and called
the fourth ventricle.

  * Disp. de Infundibulo Cerebri.
  f Ratio Med. torn. vi. p. 27*1.
  j: The under part of it,  however, appears to be impervious;
at least no injection that can be depended on has been made to
pass from it into the glandula pituitaria without laceration of
parts. 
          Of the Brain and Nerves,       375

  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
appears 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,
composed of medullary and cortical substan-
ces, covered by  the  pia mater \ and  which,
from its being divided  into numerous furrows?
resembling the  rings  of the  earth-worm, is
named processus  vermiformis.  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 to each other, and nearly in  a transverse
direction.  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 vita.  These ramifi-
cations unite to form  a medullary trunk; the
middle,  anterior,  and most considerable part
of which forms two processes,  the crura cere-
belli, which unite with the crura cerebri, to
form the  medulla oblongata. The last furnish-
es two other processes, which lose themselves 
376       Of tiie Brain and Nerves.

under the nates,  and thus unite  the lobes of
the cerebellum to the posterior part of the ce-
rebrum.   Under the nates we observe a trans-
verse  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 mater,  which
the  generality of  anatomists  have (though
seemingly  without reason)  considered  as  a
valve  formed  for closing the communication
between the fourth ventricle and the aquaeduc-
tus 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 union of two considerable medullary
processes of the cerebrum, called crura cerebri,
with two other smaller ones from the cerebel-
lum,  which were just  now spoken  of under
the name of crura cerebelli.
   The crura cerebri arise from the middle and
lower part of each hemisphere.   They are se-
parated from each other at their origin,  but are
united below,  where they terminate in a mid-
dle protuberance, the pons Varolii, so called,
because  Varolius  compared it  to a  bridge.
This  name, however, can convey  no idea of its
real  appearance.   It is, in fact, nothing more
than  a medullary protuberance, nearly of a se-
mi-spherical shape, which unites the crura ce-
rebri to those  of  the cerebellum. 
          Of the  Brain and Nerves.       377

   Between the crura cerebri, and near the an-
terior edge of the pons Varolii, are two tuber-
cles, composed  externally of medullary, and
internally of cineritious, substance, to  which
Eustachius first  gave the name  of eminentia
mamillares.
   Along  the middle  of the posterior surface
of the medulla oblongata, where  it  forms the
anterior part of the fourth ventricle, we observe
a kind of furrow  which runs downwards and
terminates in a point.  About an inch above
the lower extremity of this fissure, several me-
dullary filaments are to be seen running to-
wards  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 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 emi-
nences, which were  described by  Eustachi-
us, but received  no particular appellation till
the time  of Vieussens,  who  gave  them the
names  of corpora olivaria and corpora pyramir
dalia.   The  former are the outermost, being
placed one on each side.  They are nearly of
an oval shape, and are composed of medulla,
with streaks  of cortical substance.   Between
these are  the corpora pyramidalia, 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 ca-
                     3  B 
378       Of the  Brain and Nerves,

nal,  from the great  foramen of the occipital
bone to the bottom of the last lumbar vertebra,
is a continuation 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 only by means of cellular mem-
brane ; but between the several vertebrae, 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 large veins.
These  are two in number, and are seen run-
ning 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 verte-
bral, intercostal, and sacral veins.
   The pia  mater is connected with the dura
mater  by means  of a thin transparent  sub-
stance  which from  its indentations  between
the spinal nerves has  obtained the name of
ligamentum denticulatum.  It is somewhat firm-
er than the tunica arachnoidea, but in other  re-
spects resembles  that membrane.    Its use is
to support the spinal 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 v^er- 
         Of the Brain and Nerves.       379

tebra,  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, resem-
bling 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 in the  same direc-
tion.   The  upper ones are  thinner  than the
rest, 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 low-
ermost nerves  exhibit an  appearance that  is
called  cauda equina, from its resemblance to a
horse's tail.
  The arteries that ramify through the differ-
ent parts of the brain, are derived from the
internal carotid and from the vertebral arteries.
The medulla spinalis is supplied  by the ante-
rior and posterior spinal arteries,  and likewise
receives branches,  from the cervical,  the infe-
rior and superior intercostal, the lumbar, and
the sacral arteries.
         Sect.  II.   Of the Nerves.

  The nerves are medullary chords,  differing
from each  other in  size,  colour, and consist-
ence,  and  deriving  their  origin from the me-
dulla oblongata and  medulla spinalis.    There
are 39, and sometimes 40, pair of these nerves; 
 380       Of the Brain and Nerves.

nine*  of which originate  from  the medulla
oblongata, and 30 or 31 from the medulla spi-
nalis.  They  appear to be perfectly inelastic,
and likewise to  possess no irritability.   If we
irritate muscular fibres, they immediately con-
tract ; but nothing of this sort happens  if we
irritate a nerve.   They carry with them a co-
vering from the pia mater; but derive no  tu-
nic from the dura  mater, as hath  been gene-
rally, though erroneously, supposed, ever since
the time of Galen,f the outer covering of the
nerves being in fact nothing more than the cel-
lular membrane.  This covering is very thick
where  the nerve is exposed to  the  action of
muscles ;  but where it  runs through a bony ca-
nal, or is secure from pressure, the cellular
tunic is extremely thin, or altogether wanting.
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:  l.
The  nervi olfactorii, distributed through  the
pituitary  membrane, which constitutes the or-
gan of smell.   2. The optici, which  go  to the

  * It has been usual to describe the ten pair of nerves as aris-
ing from the medulla  oblongata ; but  as the tenth pair arise in
the fame manner as the other spinal nerves,  Santorini,  Heister,
Haller, and others, seem  very  properly to have classed  them
among the nerves of the spine.
  -j- 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 foramina that
afford a passage to the nerves out of the cranium, and vertebral
eanal, or is soon lost in the cellular substance. 
           Of the Brain and Nerves.       381

eyes, where  they  receive  the impressions of
visible objects.  3. The oculorum motores, so
called because they are distributed to the mus-
cles of the eye.   4. The pathetici, distributed
to the superior oblique  muscles of the eye, the
motion of which is expressive of certain passions
of the soul.   5.  The nerves of this pair soon
divide into three principal branches,  and each
of these  has a different name.   Its  upper di-
vision is  the ophthalmicus, which is distribut-
ed to various parts of the eyes, eye-lids,  fore-
head,  nose, and integuments of the face. The
second is  called the  maxillaris superior,  and
the third maxillaris inferior ; both which names
allude to their distribution.   6.  The abducto-
res ; 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,*  which are distribut-
ed  through the  organs of hearing.    8. The
par vagum, which derives  its name  from the
great number of parts to which it gives branch-
es both in the thorax  and  abdomen.   9. The
linguales, or hypo-glossi, which are distribut-
ed to the tongue,  and appear to contribute both
to the organ of taste and to the  motions of the
tongue.f

  * This pair, soon after its entrance into the meatus auditorius
internus, separates into two branches. One of these is of a very
soft and pulpy  consistence, it is called the portio mollis of the se-
venth 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 portio dura, and is distribut-
ed to the external ear and other p.irts of the neck and face.
  •j Heister has summed up  the ufes of these nine pair of
nerves in the two following Latin verses: 
382       Of the Brain  arid  Nerves.
   It has already  been  observed, that the spi-
nal  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
commonly distinguished into the cervical, dorsal,
lumbar, and sacral nerves.   The cervical, which
pass out from between  the several  vertebrae
of the neck are eight*  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  posterior, surface of the  medulla.
These fasciculi  are  separated  by the ligamen-
tum denticulatum; after which  we find them
contiguous to one another.   They then perfo-
rate the dura  mater, and unite to  form  a con-
siderable  knot or ganglion.   Each  of these

    " Ol/aciens, cernens, oculosque movens, patiensque,
     " Gastans, abducens, audiensque, vagansque, loquensque.v
   *  Besides these, there is another  pair called accessorii, which
arises from the medulla spinalis at its beginning; and ascending
through 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 j  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
ancients considered them as branches of the eighth pair,  distri-
buted to muscles of the scapula : Willis likewise considered them
as appendages to that pair, and on that account named them ac-
cessorii.  They are sometimes called the spinal pair ; but as this
latter name is applicable to all the nerves of the spine indiscrimi-
nately, it seems better to adopt that given by Willis. 
          Of the Brain and Nerves.      383

 ganglions sends off two branches ; one ante-
 rior, and the other posterior.   The  anterior
 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 vari-
 ous parts of the body.   They  occur in  the
 nerves of the medulla oblongata,  as well as in
 those of the spine.  They are not the effects
 of disease,  but are to be met with in the same
 parts of the same  nerves, both  in  the foetus
 and adult.  They are commonly of an oblong
 shape, and of a greyish colour, somewhat in-
 clined to red,  which is perhaps owing to their
 being  extremely vascular.  Internally we  are
 able to distinguish  something like an intermix-
 ture of the nervous filaments.
   Some  writers  have considered them as so
 many little brains ;  Lancisi fancied he had dis-
 covered muscular fibres in them, but they are
 certainly  not  of an irritable nature.   A late
 writer, Dr.  Johnstone,*  imagines they are in-
 tended to deprive us of the  power of the will
 over certain parts, as the heart,  for instance:
 but if this hypothesis were  well  founded,  we
 should meet with them only in the nerves lead-
ing to involuntary muscles ; whereas it is cer-
tain, that the  voluntary  muscles receive their
nerves through  ganglions.    Doctor  Monro,
from observing the accurate intermixture of the
* Essay on the Use of the Ganglio-s of the Nerves. 
384        Of the  Brain and Nerves.

minute nerves which compose them, considers
them as new sources of nervous energy.f
   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
considerable  enough to be  distinguished  by
particular names, as the semilunar plexus; the
pulmonary plexus; the hepatic, the cardiac, he.
   It would be foreign to the purpose of this
work, to  follow the nerves  through all their
distributions ; 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
universal connection and correspondence with
all the other nerves of the body.  Authors are
not  perfectly agreed about the origin  of the
intercostal ; but it may perhaps not  improperly
be described, 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 vertebra?, and receives branches
from almost  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
f Observations on the Nervous System. 
          Of the Brain and  Nerves.      385

those cavities, and forms several plexuses with
the branches of the eigiith pair or parvagum.
   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  determine.  The
inquiry has been a constant source of hypothesis
in ail 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 conveyed   to  the   sensorium commune.
Others have supposed  it to  be a canal, which
afterwards separates into more minute channels;
or,  perhaps, as being an assemblage of many
very small and distinct  tubes, connected  to
each other,  and  thus  forming a  cylindrical
chord.  They  who contend for  their being
solid bodies, are  of opinion,  that feeling  is
occasioned by  vibration: so that, for instance
according  to  this system,  by  pricking  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 con-
nection,  and the situation  of  the nerves,  are
 so many proofs that vibration has no share in
the cause of feeling.
                      3 C 
386      Of the Brain and Nerves.

  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 spi-
nal  marrow,  from whence  it passes through
the  medullary 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 support*



  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
  origin and large portions of all the Nerves.

  AA,  The  anterior lobes of the cerebrum.
BB, The lateral lobes of the cerebrum.  CC,
The two lobes of the cerebellum.  D, Tuber
annulare.  E,  The passage from the third
ventricle to  the infundibulum.   F,  The  me-
dulla oblongata, which sends off the  medulla
spinalis through the spine.  G G, That part
of the os occipitis which is placed above (H H)
the transverse  processes of the first cervical
vertebra.   I I, he.  The seven cervical verte- 
Ci-
£
S 
 
         Of the  Brain and  Nerves.      387

bras, with their intermediate cartilages.   K K,
he.  The  twelve dorsal vertebrae, with their
intermediate cartilages.  L  L,  he. The five
lumbar vertebrae, with  their  intermediate car-
tilages.  M, The os sacrum.  N, The os coe-
cygis.

   Nerves.— 1 1, The first pair of nerves, nam-
ed olfactory, which go to the nose.  2 2, The
second pair, named optic, which goes to form
the  tunica retina of the eye.  3 3, The third
pair, named motor oculi; it supplies  most of
the  muscles of the eye-ball.   4 4, The fourth
pair, named pathetic,—which is wholly spent
upon the musculus trochlearis of the eye. 5 5,
The 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 superior maxillary, sup-
plies the teeth  of the upper jaw, and some of
the  muscles of the  lips.—The third named in-
ferior  maxillary, is spent upon the muscles
and teeth of the lower jaw, tongue, and mus-
cles of the lips.   6 6, The sixth pair,  which,
after sending off the beginning of the intercos-
tal or great sympathetic, is spent upon the ab-
ductor  oculi.  7 7, The seventh pair, named
auditory,   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 re-
flected branch from the second of the fifth.;
and within the tympanum, by a branch from
the third of the fifth named  chorda tympani.*— 
388       Of the Brain and Nerves.

Vid. fig. 3. near B. 8 8, he. The eighth  pair,
named par vagum,—which accompanies  the
intercostal, and is spent upon  the  tongue,  la-
rynx, pharynx, lungs,  and abdominal viscera.
9 9, The ninth pair, which are spent upon the
tongue.   10  10, he. 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 the  sternocleido-mastoi-
daeus and  trapezius muscles.  12 12, The first
cervical nerves;—13 13,  The second cervical
nerves ;—both spent upon the muscles that  lie
on the neck,  and teguments of the neck and
head.  14 14, The third cervical nerves, which,
after  sending off  (15  15,  he.)  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, se-
venth cervicals,  and first dorsal nerves ; which
supply the muscles and  teguments of the su-
perior  extremity.  17 17,  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.   18
18, The five  lumbar  pairs of nerves, which
supply  the lumbar and  abdominal  muscles,
and some  of the  teguments and muscles of the
inferior extremity.  19 19, The sacro-sciatic,
or posterior crural nerve,  formed by the two
inferior lumbar,  and three superior of the os 
          Of the Brain and Nerves.      389

sacrum.   This large nerve supplies the great-
est part of the muscles and teguments of the
inferior extremity.  20, The stomachic plexus,
formed by the eighth pair.  21 21, Branches
of the solar or caehac plexus,  formed by the
eighth pair and intercostals, which supply the
stomach and   chylopoietic  viscera.   22 22,
Branches of the  superior and inferior mesen-
teric plexuses, formed by the eighth pair and
intercostals, which supply the chylopoietic vis-
cera,  with  part  of the organs  of  urine and
generation.  23 23,  Nerves which accompany
the spermatic  cord.  24 24, The hypogastric
plexus, which supplies the  organs  of urine
and generation within the pelvis.


Fig. 2, 3, 4, 5.   Shows different Views of the
   Inferior part of the  Brain, cut perpendicu-
   larly through the Middle,—with the Origin
   and large Portions of all the Nerves which
   pass out through the Bones of the Cranium,
   —and the three first Cervicals.

   A,  The anterior lobe.  B, The lateral lobe
of the cerebrum.   C, One of the lobes of the
cerebellum.   D, Tuber annulare.  E, Corpus
pyramidale, in the middle of the  medulla ob-
longata.   F,  The corpus olivare, in the side
of the medulla  oblongata.  G, The medulla ob-
longata.  H, The medulla spinalis.

   Nerves.— 1 2 3 4 5 6 7 8 and 9, Pairs of
nerves.  10 10,  Nervus  accessorius,  which
comes from—11, 12, and IS, The three first
cervical nerves. 
390    Of the Senses and their Organs.
PART VI.   OF THE SENSES  AND
          THEIR  ORGANS.
  IN treating of the senses, we mean to con-
    fine 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  impressions to the  sensorium.
Each of these organs being of a peculiar struc-
ture, is  susceptible only of particular impres-
sions, which will be pointed  out as we pro-
ceed to describe each of them separately.


             Sect. I.  Of Touch.

  The sense of touch maybe defined  to  be the
faculty of distinguishing  certain properties of
bodies by the feel.  In a general acceptation,
this definition might perhaps  not  improperly
be extended to every part of the  body possess-
ed  of sensibility,*  but it  is  commonly con-

  *  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 in this place,
that many parts which were formerly supposed 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  Senses and their Organs.    391

fined  to  the nervous  papillae of  the cutis, or
true  skin,  which,  with its appendages, and
their  several  uses,  have   been  already de-
scribed.
   rI he exterior  properties of bodies,  such as
their  solidity,  moisture,  inequality,  smooth-
ness,  dryness, or fluidity,  and likewise their
degree of heat, seem all to  be capable of mak-
ing different impressions on the  papillae, and
consequently of exciting different ideas in the
sensorium commune.   But the organ of touch,
like all the other senses,  is not  equally deli-
cate  in every part  of the  body,  or in every
subject; being in some much more exquisite
than it is in others.
           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 papillae, which, on
account  of  their difference in size and shape,


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, pericardium,  dura and pia mater, periosteum, Sec. j
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 of nerves.   Upon
this principle it is, that the  skin, muscles, stomach, intestines,
urinary bladder, ureters, uterus, vatina peni:, tongue, and re-
tina, are extremely sensible, while the lung* and  glands haw-
only an obscure degree of feeling. 
 392   Of the Senses and their  Organs.

 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
 follicles.  Those of the second class are some-
 what 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 lingua mediana,
 running along the middle  of  the tongue, and
 dividing it as it were into two portions.  To-
 wards the basis of the tongue, we meet with
 a  little  cavity, named by Morgagni foramen
 ccecum,  which seems to be nothing more than
 a common termination of some of the excretory
 ducts of  mucous  glands  situated within  the
 substance of the tongue.
   We have already observed, that this organ
is  every where covered by the cuticle, which,
 by forming a reduplication, called the franum,
 at its under  part,  serves  to  prevent  the  too
 great motion of the  tongue, and  to fix it in its
 situation.   But,  besides this  attachment, the
 tongue is  connected 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
jugulars.  Its nerves arise from the fifth, eighth,
 and  ninth pair. 
       Of the  Senses and their Organs.    393

  The variety of tastes seems to be occasioned
by the different impressions made on the papil-
lae by the food.   The different state of the pa*
pUlae with respect to their moisture, their figure,
or their covering, seems to produce a consider-
able difference in the taste, not only in  differ-
ent 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 having
their  papillae*  very  large and long, have the
faculty of distinguishing flavours with infinite
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 in-
ternal parts.   The situation and figure of the
former of these do not seem to require a defini-
tion.   It is composed of bones and cartilages,
covered by muscular fibres and by the common
integuments.   The  bones make up  the  upper
portion,  and the cartilages the lower one. The
septum narium,  like the nose, is  likewise in
part bony, and in part cartilaginous.  These
bones and their connections were described in
the osteology.
                     3 i)

  * Malpighi's description of the papillae, which has been copied
by many anatomical writers, seems to have been taken chiefly
from the tongues o^ -Heep. 
 394   Of the  Senses and their Organs.

   The internal part  of the nose, besides the
 ossa spongiosa,  has  six cavities or  sinuses,
 the maxillary,  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 be-
 hind the velum palati.
   All these several parts, which are included
 in the internal division of the nose, viz. the in-
 ner surface of the nostrils, the lamellae of the
 ossa spongiosa, and the sinuses, are lined by
 a thick and very  vascular membrane, which,
 though not unknown to the ancients, was first
 well described by 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 perfectly 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 moist-
 ened by a mucous secretion;  the finer parts of
 which are carried off by the air we breathe,
 and the  remainder, by being retained in the
 sinuses,  acquires  considerable  consistence.
 The manner in which this mucus is secreted
has not yet been satisfactorily 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
* De Catarrho, lib. iii. 
        Of the Senses and their Organs.   395

  over every part of it, and it likewise receives
  branches from the fifth pair.
    After what has  been said of the pituitary
  membrane, it will not be difficult to conceive
  how the air we draw in at the nostrils, being
  impregnated  with the  effluvia of bodies,  ex-
  cites in us that kind of sensation we call smell'
  ing.  As these effluvia, from their being ex-
  ceedingly light and volatile, cannot be  capable
  in a small  quantity of making any  great im-
  pression on the extremities of  the olfactory
  nerves,  it was necessary to give considerable
  extent to the  pituitary membrane, that by this
  means a greater number of odoriferous parti-
  cles 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  nos-
  trils ; and at  the same time, by  means of the
  muscles of the nose, the nostrils 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  sub-
  ject it seems  to be more perfect the-less  it is
  vitiated  by a variety of smells.   It is not al-
  ways in the same state of perfection, being na-
  turally affected by every change of the pitui-
  tary membrane, and of the lymph with whicrj
1  that membrane is moistened. 
396    Of tiie Senses and their Organs.


           Sect., IV.   Of Hearing.

   Before  we undertake to  explain the man-
ner in which we are enabled to receive the im-
pressions of sound,  it will be necessary to de-
scribe the ear,  which is the organ of hearing.
It is commonly distinguished into external and
internal.  The former  of these divisions in-
cludes all that  we are able to discover without
dissection,  and the meatus  auditorius, as far
as the tympanum -r and the latter, all the other
parts of the ear.
   The external ear is  a cartilaginous funnel,
covered by the common integuments, and at-
tached, by means of its  ligaments and muscles,
to the temporal bone.   Although capable only
of a very obscure motion, it is found  to have
several muscles.  Different parts of it are  dis-
tinguished  by  several  names;  all its cartila-
ginous part is called ala or wing, to distin-
guish it from the soft and pendent part below,
called the lobe.   Its outer circle  or border is
called helix, and the semicircle  within this,
antihelix.   The moveable cartilage placed im-
mediately before the meatus auditorius, which
it may  be  made to close exactly, is named
tragus;  and an eminence opposite to this at
the extremity of the antihelix,  is  called anti-
tragus.  The concha is a considerable cavity
formed by the  extremities of the helix and an-
tihelix.  The meatus auditorius, which at its
opening is  cartilaginous, is lined with a very
thin membrane, which  is a continuation of the
cuticle from the surface of the ear. 
       Of the Senses and their Organs.   397

  In this canal we  find a yellow wax, which
is secreted by a number of minute glands  or
follicles, each of which has an excretory duct.
This secretion, which is at first of an oily con-
sistence, defends the membrane of the tym-
panum from the injuries of the air ; and by its
bitterness,  prevents minute insects from enter-
ing into the ear.  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 very1
thin transparent membrane,  the membrana
tympani, which is set in a bony circle like the
head of a drum.  In the last century Rivinus,
professor at Liepsic, 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 cer-
tainly does not exist.  Whenever there is any
opening in the membrana tympani, it may be
considered  as  accidental.   Under the  mem-
brana tympani runs a branch of the fifth pair
of nerves,  called chorda tympani;  and beyond
this membrane is the cavity of the tympanum,
which is about seven or eight lines wide, and
half so many 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 anteri-
or  and  almost superior part of the tympanum. 
398    Of the Senses and their Organs.

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  membrane that covers the
inside of the mouth.   The real use of this ca-
nal does not seem to have been hitherto satis-
factorily 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 process;
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.  Besides  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
handle.  The latter is attached to the  mem-
brana  tympani, and the head of the  bone is
articulated 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 widely separated from each  other, is 
       Of the Senses and their Organs.    399

distinguished into its body and  its legs.  One
of its legs is placed at the entry of the canal
which leads  to the mastoid  process; and the
other, which is somewhat longer,  is articulat-
ed with the stapes, or rather with  the os orbi-
culare,  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 orbicu-
lare.   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 eminence formed by the os petro-
sum,  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 sta-
pedeus and tensor tympani.   The first of these,
which is the smallest in the  body, arises from
a little cavern in the posterior and upper part
of the cavity of the tympanum;  and its tendon,
after passing through a hole in the same  ca-
vern, is inserted at  the back part of the head
of the stapes.   This muscle, by  drawing the
stapes obliquely upwards, assists in stretch-
ing the membrana tympani.
  The tensor tympani,* or internus mallei, as
it is  called  by  some writers,  arises from the
cartilaginous extremity of the Eustachian tube,
and is inserted into the back part of the handle

  * Some anatomists describe three muscles of the malleus; but
only this one seems to deserve the  name of muscle; what are
called the externus and obliquus mallei,  seeming to be ligaments
rather than muscles. 
400   Of the Senses and their Organs,

of the malleus, which it serves to pull inwards,
and of course helps to stretch the membrana
tympani.
   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  fenestra?.   It is com-
posed of three parts; and these are the vesti-
bulum,  the semicircular  canals, and the coch-
lea.
   The vestibulum is an irregular cavity, much
smaller than the tympanum, situated nearly in
the centre of the os petrosum, between the
tympanum, the cochlea,  and the semicircular
canals.   It is open on the side of the tympa-
num by means of the fenestra ovalis, and com-
municates with the  upper portion of the coch-
lea by an oblong  foramen, which is under the
fenestra ovalis, from which it is separated only
by a very thin partition.
   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 ho-
rizontal.  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.
   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 lamina or septum, which is in  part bony 
      Of the Senses and their Organs.   401

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  vestibulum, and the other is covered
by the membrane that closes the  fenestra ro-
tunda.  The bony lamella which separates the
two canals is exceedingly thin, and fills about
two-thirds of the diameter of the  canal.  The
rest of the septum is composed of a most deli-
cate membrane,  which  lines the  whole inner
surface of the cochlea, and seems  to form this
division in the same manner as the two mem-
branous bags of the pleura, by being applied
to each other, form the  mediastinum.
  Every part of the labyrinth is furnished with
a very delicate  periosteum,  and filled  with a
watery fluid, secreted as in other cavities.  This
fluid  transmits  to the nerves the vibrations it
receives from the membrane closing the fenes-
tra rotunda, and from the basis of the stapes,
where it  rests on the fenestrum ovale.  When
this fluid is collected  in too great a quantity,
or is compressed by the stapes, it  is supposed
to escape through two minute canals or aque-
ducts, lately described by Dr. Cotunni,* an in-
genious  physician  at Naples.  One of these
aqueducts  opens into  the bottom of the ves-
tibulum,  and the other into  the cochlea, near
the fenestra rotunda.  They both pass through
the os petrosum, and communicate with the ca-
vity of the cranium where the fluid that passes
through them is absorbed; and they are lined

                     3 E

   * De aquseductibus Auris Humans Interna, 8vo, 1760, 
402    Of the  Senses and their Organs.

by a membrane which is supposed to be a pro-
duction of the dura mater.
  The artei>s of the external ear come from
the temporal and other branches of the exter-
nal carotid, and its veins pass into the jugular.
The internal ear  receives branches of arteries
from  the  basilary and carotids, and its veins
empty themselves into the sinuses of the dura
mater, and into the internal jugular.
  The portio mollis of the seventh pair is dis-
tributed through  the cochlea, the vestibulum,
and  the  semi-cireular  canals ;  and the portio
dura sends off a branch to the tympanum, and
other branches to the external  ear and parts
near k.
  The sense of hearing, in producing  which
all the parts we have described assist, is occa-
sioned by a certain modulation of the air col-
lected by the funnel-like shape of the external
ear, and conveyed through the meatus audito-
rius  to the membrana tympani.  That  sound
is propagated by means of the air, is  very ea-
sily proved by ringing a bell under the receiv-
er of an  air-pump; the sound it affords being
found to diminish gradually as the air becomes
exhausted, till  at  length it ceases to be heard
at all.  Sound moves through the air with in-
finite 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.
  That the air  vibrating on the membrana
tympani communicates its vibration to the dif-
ferent parts of the labyrinth,  and by means  of 
      Of the Sefises and  their Organs.    403

the fluid contained in this cavity affects the au-
ditory nerve so as to produce sound, seems to
be  very probable ;  but the situation, the  mi-
nuteness,  and the  variety of the parts  which
compose the ear,  do not permit much to be ad-
vanced with certainty concerning their mode of
action.
   Some of these  parts seem to constitute  the
immediate organ of hearing, and these  are all
the parts of the vestibulum;; but there ate others
which seem intended for the perfection of this
sense, without being absolutely essential to it.
It has happened, far instance, that the mem-
brana tympani, and the little bones of the ear,
have been destroyed by disease, without de-
priving .the patient  of the sense of hearing..*
   .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 fre-
quent 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  fiave  a relation to  the organ of
hearing.
   Every body has, in consequence of particu-
lar sounds,  occasionally  felt that disagreeable
sensation  which  is  usually  called setting  the
teeth on edge: and the cause of this sensation

  * This observation has led to a supposition, that a perforation
of this membrane may in some cases of deafness be useful; and
Mr. Cheselden relates, that, some years ago, a 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. 
404   Of the Senses and their Organs.

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 tym-
pani by these very acute sounds.  Upon the
same principle we may explain the strong idea
of sound which  a person has  who holds  a vi-
brating  string between his  teeth.
   The  humming which is sometimes perceiv-
ed in the ear, without any exterior cause, may
be occasioned either by an increased action of
the arteries in  the ears, or by convulsive con-
tractions  of the muscles of the  malleus and
stapes,  affecting the auditory  nerve in such a
manner as to produce  the idea of sound.   An
ingenious philosophical writer* has lately dis-
covered that there are sounds liable  to be ex-
cited 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 palpebral, which are com-

  * Elliot's Philosophical Observations on the Senses of Vision
and Hearing, 8vo. 
      Of the Senses and their  Organs.   405

posed  of  muscular fibres covered by the com-
mon integuments, and lined by a very fine and
smooth membrane,  which  is from thence ex-
tended 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 cilia serve to protect the eye  from  in-
sects and  minute bodies floating in the air, and
likewise to moderate the action of the rays of
light in their passage to  the retina.  At  the
roots of these hairs  there are sebaceous folli-
cles, first noticed by Meibomius, which dis-
charge 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 serv-
ing to protect the eyes, but they are probably
intended more for ornament than utility.*
   The orbits in which the eyes are placed, are
furnished with a good deal of fat,  which  af-
fords a soft bed on which the eye performs  its
several motions.   The  inner angle of each  or-
bit,  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.

  * It is observable, that the eye-brows are peculiar to the hu-
man species. 
406    Of the Senses and their Organs.

   The little reddish body which we observe
in the great angle of the eye-lids, and which is
called caruncula lachrymalis,  is supposed to be
of a glandular structure, and,, like the follicles
of the eye-lids, to secrete an oily humour.  But
its structure and use do not seem to have been
hitherto accurately determined.   The surface
of the  eye  is constantly  moistened by a very
fine limpid fluid called the tears, which is chief-
ly,  and perhaps wholly,  derived from a large
gland of the  conglomerate kind, situated in a
small depression of the os frontis near the out-
er angle of the eye.  Its excretory ducts pierce
the tunica conjunctiva  just above the cartila-
ginous borders of the upper eye-lids.  When
the tears were supposed to be secreted by the
caruncule, this gland Wats  called glandula inno-
minata; but now that its structure and uses
are ascertained, it very  properly has the name
of glandula lachrymalis.    The tears poured
out by the ducts of this  gland are,  in a natur-
al and healthy stated incessantly spread over the
surface of the eye,  to keep it clear  and trans-
parent, by  means of the eye-lids, and as con-
stantly pass out at the opposite corner of the
eye or inner angle, through two minute  orifi-
ces, the puncta lachrymalia ;* being determined
into these little openings by a reduplication of
the tunica conjunctiva, shaped  like a crescent
the two points of which  answer  to  the puncta.

  * It sometimes happens, that this very pellucid fluid, which
moistens the eye,  being poured out through the excretory ducts
of the lachrymal gland faster than it can be carried off through
the puncta, trickles down the cheek, and is then strictly and pro-
perly called tears. 
      Of the  Senses and their Organs.    407

This reduplication is named membrana, or val-
vula semilunaris.   Each of these puncta is the
beginning of a small excretory tube,  through
which the tears pass  into a little pouch or re-
servoir,  the sacculus lachrymalis, which lies
in an excavation formed partly by the nasal
process of the os  maxillare superius, and part-
ly 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.*
   The motions of the  eye are performed by
six muscles ; four of which  are  straight and
two oblique.   The straight  muscles  are  dis-
tinguished  by the names  of elevator, depres-
sor,  adductor,  and  abductor,  from their se-
veral 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 or-
bit, 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 obli-
quus superior, does not,  like the other four mus-
cles we have  described, arise from the bottom
of the orbit, but from  the edge of the  fora-
men that transmits the  optic nerve, which se-
parates the origin  of this muscle  from that of

  ,* "When the ductus ad nares  becomes obstructed in  conse-
quence of disease, the tears are no longer able to pass into the nos-
trils ; the sacculus lachrymalis becomes distended ; and inflam-
mation, and sometimes  ulceration taking place, constitute the
disease called fistula lachrymal; r. 
 408   Of the Senses and  their Organs.

the others.   From this beginning it passes in
a straight line towards a very small cartilagin-
ous ring, the  situation 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 upper 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
lachrymalis ; and is inserted somewhat  poste-
riorly 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, hu-
mours, and component parts,  is  nearly of a
spherical figure.   Of its tunics,  the conjuncti-
va has been already described as a partial co-
vering, 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 all the other  parts with which it  is sur-
rounded, are removed, are the sclerotica, cor-
nea, choroides, and retina. 
       Of the  Senses and their Organs.    409

   The sclerotica, which is the exterior coat,
is every where white and opaque*  and is join-
ed at its anterior edge to another, which has
more convexity  than  any  other  part of the
globe, and being exceedingly transparent  is
called cornea.*   These two parts are perfectly
different in their structure; so that some ana-
tomists 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 num-
ber of laminae united by cellular membrane.
By macerating them in boiling water, they do
not separate from each other, as some writers
have  asserted; but the  cornea  soon softens,
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
opinion ; 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 choroides  is so  called because it is fur-
nished with a great number of vessels.   It has
likewise been named uvea*, on account of its re-
semblance to a grape.  Many modern anatomi-
cal writers have considered it as a production
of the pia mater.  This was likewise the opinion
                    3 F

  * Some writers, who have given the name of cornea to all this
outer coat, have named what is here and most commonly called
sclerotica, cornea opaca ; and its anterior and transparent portion,
eomea lucida. 
410    Of the Senses and their Organs.

of the ancients;  but the strength and thickness
of the choroides, when  compared with the deli-
cate 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 laminae ; 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
unable to demonstrate  any such structure, al-
though 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  ciliare9
though it is not of a ligamentous nature.
  They who suppose the choroides  to be com-
posed of two laminae, 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 distin-
guish through the cornea; but this part is of a
very different structure from the choroides;
so that some late writers have perhaps not im-
properly considered the iris as a distinct mem-
brane.  It derives its name from the variety of
its colours, and  is perforated in the middle.—
This perforation, which is called the pupil or
sight of the eye, is closed in the foetus by a very
thin vascular membrane.  This membrana pu-
pillaris commonly disappears about the seventh
month. 
        Of the Senses and their Organs.    411

   On the under side of the iris we observe ma-
ny minute fibres, called ciliary processes, which
pass in radii or parallel lines from the circum-
ference to  the centre.   The  contraction and
dilatation of the pupil  are supposed to depend
on the action of these  processes.  Some have
considered  them as muscular,  but  they  are
not of an  irritable nature: others have sup-
posed  them to  be filaments  of nerves;  but
their real structure has never yet been clearly
ascertained.
   Besides  these  ciliary  processes, anatomists
usually 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 accurate and distinct  vision; but  the man-
ner in which it is secreted has not been deter-
mined.
   Immediately under the tunica choroides we
find the third and inner coat, called the retina,
which seems to be merely an expansion of the
pulpy substance  of the optic nerve, extending
to the border of the crystalline humour-
   The greatest part of  the globe of the eye,
within these several tunics, is filled by a very
transparent and gelatinous humour of conside-
rable  consistence,  which, from its  supposed
resemblance to fused glass, is called the vitre-
ous humour.  It is  invested by a very fine and
delicate  membrane, called tunica vitrea, and
sometimes  arachnoides.—It is supposed to be
composed  of  two laminae; one of which dips
into  its  substance, and  by dividing  the   hu- 
412   Of the Senses and their Organs\

mour  into  cells adds  to its firmness.   The
fore-part of the vitreous humour is  a  little
hollowed, to receive  a very white and trans*
parent substance  of a firm  texture, and of  a
lenticular and somewhat convex shape, named
the crystalline humour.   It  is  included  in  a
capsula,  which seems  to be  formed by a sepa-
ration of the two laminae 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 crystalline  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 occasioned this portion
of the eye to be  distinguished 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;  and  the
other, which is the space between the iris and
the cornea, is called  the anterior chamber of
the eye.*   Both these spaces are completely
filled with the aqueous humour.f

   * We are aware that some anatomists, particularly Lieutaud,
are of opinion, that the iris is every where in close contact  widi
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 cf the iris and the two chambers of the  eye are here
described in the usual way.
   f When the crystalline becomes opaque, so as to  prevent the
passage of the rays of light to the retina, it constitutes what  is
called a cataract; and the operation of couching consists in re-
moving the diseased crystalline from its bed in the vitreous hu-
mour.  In this operation the cornea is perforated, and the aque-
ous 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; 
       Of the Senses mid their Organs.   4,13

 ; The  eye receives its  arteries from the in-
ternal  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 ap-
pear on the  inner surface of the  iris, where
they are seen to  make very minute convolu-
tions, which are sufficiently remarkable to be
distinguished by the name of circuius arteriosus^
though  perhaps improperly, as they are chief-
ly branches of veins.
  The optic nerve passes  in at the posterior
part of the eye, in a considerable trunk, to be
expanded for the  purposes of vision, of which
it is now  universally supposed to be the im-
mediate seat.  But Messrs. Mariotte and Mery
contended, 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  retina,  as in the camera obscura, the ob-
ject is painted in an inverted position; and it
is only  by  habit that we are enabled to judge
of its true situation,  and  likewise of its  dis-
tance and magnitude.  To a young gentleman
who was born blind, and who was couched by
Mr. Cheselden,  every object (as he expressed
himself) seemed  to touch his eyes as what he 
>414   Of the Senses and their Organs.

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
retina, the cornea is required to have such a
degree of convexity, that the rays of light may
be collected  at a certain point, so as to termi-
nate  exactly  on the retina.—If the  cornea is
too prominent, 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 suf-
ficiently convex, the rays will not  be perfectly
united when  they reach the back part of  the
eye; and this happens to long-sighted people
or presbi, being found constantly to take place
as we approach to old  age,  when the eye gra-
dually flattens.*  These defects are to be sup-
plied by means of glasses.   He who has  too
prominent an eye, will find his vision improv-
ed by means  of a  concave glass; and  upon
the same principles,   a  convex glass will be
found useful to a person whose eye is  natu^
rally too flat.

   * Upon this principle, they  who in their youth are near sight-
ed may expect to see better as they advance in life, as their eyes
gradually become more flat. 
 
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Of the Senses and their Organs.    415
   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 punc-
ta lachrymalia,  from which the two lachry-
mal  canals  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
            Humours of the Eye.

  a a a a, The tunica sclerotica cut in four
angles,  and  turned back,  b b b b, The tunica
choroides  adhering to the inside of the sclero-
tica, and  the ciliary  vessels are  seen passing
over—c c, The retina which covers the vitre-
ous  humour.   d  d,  The  ciliary  processes,
which  were  continued from the choroid coat.
e e,  The iris,   f,  The pupil.


Fig. 3.   Shows the  Optic Nerves, and Mus-
              cles of the Eye.

  a a, The two optic nerves before they meet.
b? The two  optic  nerves conjoined,  c, The 
415    Of the Senses and their Organs.

right optic nerve,  d, Musculus attollens pal-
pebral superioris.  e, Attollens oculi.   f, Ab-
ductor,   g g, Obliquus superior, or  trochle-
aris.  h, Adductor,  i,  The eye-ball.


Fig. 4.  Shows the Eye-ball with its Muscles.

  a, The optic nerve,   b, Musculus  trochle-
aris.  c, Part of the os frontis, to which the
trochlea or pully is fixed, through which,—d,
The tendons of the trochlearis passes,   e, At-
tollens oculi.  f,  Adductor oculi.   g,  Abduc-
tor  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, Attollens.
E, Levator palpebral superioris.   F, Depres-
sor oculi.  G, Adductor.  H, Obliquus  superi-
or,  with  its pully.   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, Trans-
verse spinous process  of the sphenoid bone.
P, The carotid artery, denuded where it pass-
es through the bones.   Q,, The carotid artery
within the cranium.   R,  The ocular artery. 
        Of the Senses and their Organs.    417

   Nerves.—a a, The optic  nerve,  b, The
third pair.—c, Its joining with a branch of the
first branch of the fifth pair, to form 1,—The
lenticular ganglion, which sends off the ciliary
nerves, d. e e, 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.    1,
The  lenticular  ganglion.  m,   The  second
branch of the fifth pair, named  superior max-
illary,   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 abductor 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.

   A A,  The cut edges of the upper part of
the cranium.   B, The two tables and interme-
diate diploe.  B B, The two  hemispheres of
the cerebrum.    C C, The  incisure made  by
the falx.   D, Part of the tentorium cerebello
super expansum.   E, Part of the falx, which
is fixed to the crista galli.
3 G 
418    Of the Senses and their, Organs.

Fig. 7. Represents  the  parts of the External
  Ear, with the Parotid Gland and its Duct.

  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.   i i, The  parotid
gland,   k,  A lymphatic gland, which is often
found before  the tragus.  1,  The duct of the
parotid gland,   m, Its opening into the mouth.


Fig. 8.  A view of the posterior part of the
  external ear, meatus auditorius, tympanum,
  with the 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,  The Eustachian tube,  g,
Its mouth from the fauces.

Fig.  9.  Represents the anterior part  of the
   right external ear, the  cavity of the tympa-
   num—its small bones, cochlea, and semicir-
   cular canals.

   a,  The malleus,   b,  Incus wit^ its lan£ leg,
resting upon  the stapes,   c, Membrana tym-
pani.  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 por-
tio mollis of the seventh pair of nerves. 
       Of the Senses and their Organs,   419

Fig. 10. Shows the muscles which compose
    the fleshy substance of the Tongue.

  a a, The tip of the tongue, with some of the
papillae minimae.   b, The root of the tongue.
c, Part  of the membrane of the tongue, which
covered the epiglottis.   d d,  Part of the mus-
culus hyo-glossus.  e, The lingualis.  f, Ge-
nio-glossus.  g g,  Part of the stylo-glossus.
THE  END. 
 
 
 
Med,. Hist.
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