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SYSTEM OF  ANATOMY
FOR THE USE OF
STUDENTS OF MEDICINE.
BY CASPAR WISTAR, M. D.

   PROFESSOR OF ANATOMY
           IN THE
   UNIVERSITY OF PENNSYLVANIA.
VOLUME II.  /§
                PHILADELPHIA:
PUBLISHED BY THOMASj^OBSON AND SON, AT THE STONE HOUSE,
            No. 41/SOUTH SECOND STREET.
                 William Fry, Printer.
                      1817.
X 

District of Pennsylvania, to wit:
 :"•• *•• *t   BE IT REMEMBERED, That on the twelfth day of November,
 ; SEAL.; jn tne forty.secon(i year of the independence of the United States
 ••••••••*• Qf America, A. D.  1817, Thomas Dobson and Son, of the said dis-
trict, have deposited in this office the title of a book, the right -whereof they
claim as proprietors, in the words following, to wit:

"A System of Anatomy for the use of Students of Medicine. By Caspar Wis-
  "tar, M. D. Professor  of Anatomy in the  University of Pennsylvania.
  " Volume II."

  In conformity to the act of the congress of the United States, intituled, "An
act for the encouragement  of learning, by securing the copies of maps, charts
and books, to the authors  and proprietors of such copies, during  the times
therein mentioned."—And  also to the act, entitled, " An act supplementary
to an act, entitled "An act  for the encouragement of learning, by securing the
copies of maps, charts, and books, to the authors and proprietors of such copies
during the times therein mentioned," and extending  the  benefits thereof t«
the arts of designing, engraving, and etching historical and other prints."
                                          D.CALDWELL,
                                   Clerk of the district of Pennsylvania. 
CONTENTS OF VOL. II.
                     PART  VI.
       OF THE NOSE—THE MOUTH—AND THE THROAT.

                    CHAPTER I.
                      Of the Nose.

                     SECTION I.
 UF the External Nose    .....   2

                     SECTION II.
 Of the Cavities of the Nose      -                        4

                   CHAPTER II.
            Of the Mouth and the Salivary Glands.
 Of the Mouth      ------   14
      Salivary Glands  -----      24

                   CHAPTER  III.
                     Of the  Throat.

                     SECTION  I.
 Of the Isthmus of the Fauces      -      -      -      -   29

                     SECTION II.
 Of the Larynx   ------      31
      Thyroid Gland      -----   36

                    SECTION III.
 Of the Pharynx  ------      37
                              t
                    PART VII.
                   OF THE THORAX.

                   CHAPTER I.
            Of the general Cavity of the Thorax.
                    SECTION I.
Of the Form of the Cavity of the Thorax    -      -          44 
IV
CONTENTS.
Page
                      SECTION II.
Of the Arrangement of the Pleurae                          45
Preparation of the Thorax   -      -     -      -      -   47

                     CHAPTER II.
Of the Heart and the Pericardium, and the Great Vessels  connected
                      with the Heart.

                       SECTION I.
Of the Pericardium      -----      49

                      SECTION II.
Of the Heart -------   50

                      SECTION  III.
Of the Aorta, the Pulmonary Artery and Vein, and the Venae
  Cavae at their commencement                            59

                     CHAPTER III.
                 Of the Trachea and Lungs.

                       SECTION I.
Of the Trachea     -      -      -     -      -      -   61
The Black Glands on the Branchiae      ...      64

                      SECTION II.
Of the Lungs       -      -      -     -      -      -   64
Thorax of the Foetus     .....      67
Physiological Observations, 8cc.      -     -      -         70


                      PART VIII.
                    OF THE ABDOMEN.

                      CHAPTER I.
A general view of the Abdomen and Pelvis, and their Contents; with
                an Account of the Peritoneum.

                       SECTION I.
Construction of the Abdomen    -      .      .      .      81
Contents of the Abdomen   -      -      .       .      -   86

                      SECTION II.
Of the Peritoneum       ...                   au 
              CONTENTS.                     V
                                             Page
             CHAPTER II.
Of the (Esofitiagusythe Stomach, and the Intestines.
SECTION I.
Gastric Liquor
93
(5f the Oesophagus  -

                      SECTION II.
Of the Stomach  ------      95
100
110
111
113
                     SECTION III.
Of the Intestines        -----     103
                                                      108
Division of the Intestines
The Small Intestines    -
The Duodenum     -
Jejunum and Ileon      -
The Mesentery     -
Of the Great Intestines -      -      -      -      -      lls
The Cxcum and Colon      -      -      -      -      -  116
The Rectum......l2°
The Omentum        -       -      -      -      "      122

                     CHAPTER III.
            Of the Liver, the Pancreas, and the Sfileen.

                       SECTION I.
 Of the Liver        -      -      -       -      -       -  125

                      SECTION II.
 Of the Pancreas        -      -      -      -      *     ,39

                      SECTION III.
 Of the Spleen.....-  141

                     CHAPTER IV.
         Of the Urinary Organs, and the Glandula Renales.

                        SECTION I:
 Of the Glandulae Renales       -      -       -      -    150

                       SECTION  II.
 Of the Kidneys and Ureters     -      -       -      -     152

                      SECTION III.
 Of the Urinary Bladder  -     -      -      -       -     157 
vi                    CONTENTS.

                     CHAPTER V.
              Of the Male Organs of Generation.
Page
                        SECTION I.
  Qf the Testicles and their Appendages      -      -      -   166

                       SECTION II.
  Of the Vesiculae Seminales and the Prostate Gland      -      176

                       SECTION III.
  Of the Penis......179

                      CHAPTER VI.
              Of the Female Organs of Generation.

                       SECTION I.
 Of the External Parts of Generation        -      -      -  192
                       SECTION II.
 Of the Vagina   -      -      -      -       -      -     195

                      SECTION III.
 Of the Uterus, the Ovaries, and their appendages      -     197
                      SECTION IV.
 Of the Bladder and Urethra  -----  205

                       PART IX.
                   OP THE BLOODVESSELS.

                      CHAPTER I.
   Of the General Structure and Arrangement of the Bloodvessels.

                       SECTION I.
 Of the Arteries   -      -      -      .      .       -217

                      SECTION II.
 Of the Veins        ------  224

                      CHAPTER II.
     A Particular Account of the Distribution of the Arteries.

                       SECTION I.
 Of the Aorta, or the Great Trunk of the Arterial System      227

                      SECTION II.
Of the Branches which go off from the Arch of the Aorta     229
The Carotid Arteries       -                            230
The Subclavian Arteries       ....     247 
CONTENTS.
vii
                                                        Page
                       SECTION III.
Of the Branches which go off between the Arch and the Great
  Bifurcation of the Aorta   -                           "
Bronchial Arteries
Oesophageal Arteries       -      *                         '
Inferior Intercostals     -
™   -  *                                -               2fi5
Phrenic Arteries           -
Coeliac Artery    -                                          *
Superior Mesenteric Artery -
                                                        270
Inferior Mesenteric Artery      -
Emulgent or Renal Arteries        -      -
Capsular and Adipose Arteries   -      -                    *■
Spermatic Arteries  -                                      1 '
Lumbar Arteries        -
Middle Sacral Artery
                       SECTION IV.
Of the Arteries which originate at and below the Great Bifur-
  cation of the Aorta    -
The Primitive Iliac Arteries        -       -      -      -   lb.
Internal Iliac Arteries   -                                 2'4
External Iliac Arteries     -----  279
Femoral Artery         -      -      -      -      -     280
Arteries of the Leg  -       -       -       -      -      -  283

                      CHAPTER III.
            Of the particular Distribution of the Veins.
                        SECTION I.
Of the Superior,  or Descending  Vena Cava, and the Veins
   which communicate with it     -
Vena Azygos        -
Internal Jugular Veins
External Jugular Veins     -----  297
Subclavian Vein  ------     298
                        SECTION II.
 Of the Inferior Vena Cava, and the Veins connected with it   300
 Hepatic Veins......30i
 VenaPortarum     -      -      -      *      -      -  302
 Emulgent or Renal Veins       -             -       "     3°
 Spermatic Veins    -      -      -      -
 Lumbar Veins    -      -      -  .    -      -       -      304
 Middle Sacral Vein  -      -      -      -      -      -   lb.
 Primitive Iliac Veins     -                                 lb'
292
295
ib. 
viii
CONTENTS.
                                                        Page
  Internal Iliac Veins  ------  304
  External Iliac    -                          -            305
  Femoral Vein       ...-.-  306
  Instances of Peculiar Arrangement of the Veins  -      -     307
  Of the Pulmonary Artery and Veins        ...  308


                        PART X.
                      OF THE NERVES.
 Nerves of the Brain  ------  314/
 Of the Cervical Nerves  -----     334
 Nerves of the Diaphragm    -----  33$
 Brachial Plexus   ------     337
 Nerves of the Arm   ------  338
 The Dorsal Nerves     -----     342
 Of the Lumbar Nerves     -----  343
 The Sacral Nerves      -----      346
 Sciatic Plexus      -.____   347
 Great  Sciatic Nerve     .....      345
 Great  Sympathetic Nerve      -    -      -      -       -   351
 Nerves of the Heart     -                                353
 Nerves of the Abdominal Viscera   -                       35g

                        PART XI.
                OF THE ABSORBENT VESSELS.

                      CHAPTER I.
 Of the Absorbents of the Lower Extremities—the Abdomen and the
                         Thorax.

                       SECTION I.
 The Absorbents of the Lower Extremities       -      .     366

                      SECTION II.
 The Absorbents of the Abdomen and Thorax      -      -  371

                     CHAPTER II.
 Of the Absorbents  of the Head and Neck, of the  Ufifier Extremities,
          and the Ufifier Part of the Trunk of the Body.

                      SECTION I.
Of the  Absorbents of the Head and Neck        -      -     2q2

                      SECTION II.
Of the Absorbents of the Arm, and the Upper Part of the Trunk 383 
SYSTEM OF ANATOMY.

            PART  VI.
OP  THE nose: the mouth:  and the  throat.
                    CHAPTER I.

                    OF  THE NOSE.
THE prominent part of the face, to which the word nose
is exclusively applied in ordinary language, is the anterior
covering of two cavities which contain the organ of smell-
ing.^
  These cavities are formed principally by the upper max-
illary and palate bones; and, therefore, to acquire a com-
plete idea of them, it is necessary to study these bones, as
well as the os ethmoides, the vomer, and the ossa spongi-
osa inferiora, which are likewise concerned in their forma-
tion.
  In addition to the description of these bones, in the ac-
count of the bones of the head, it will be useful to study
the description  of the cavities of the nose which follows
it. See vol. I, page 53.
  After  thus acquiring a knowledge of the bony structure,
the student will be prepared for a description of the softer
parts.
  Vol.  II.                  A 
«9
                    SECTION I.

                Of the External Nose.
  THE superior part of the nose is formed by the ossa
nasi, and the nasal processes of the upper maxillary bones,
which have been already described; (see vol. I, pages 34
—36.) but the inferior part, which is composed principally
of cartilages, is much more complex in its structure.
  The orifice, formed by the upper maxillary and nasal
bones, is divided by a cartilaginous plate, which is the an-
terior and inferior part of the septum, or partition between
the  two cavities of the nose. The anterior edge of this
plate projects beyond the orifice in the bones,  and  conti-
nues in the direction  of the suture between the ossa nasi.
This edge forms an angle with the lower edge of the same
cartilage, which continues from it, in  a horizontal  direc-
tion, until  it reaches  the lower  part of the orifice of the
nose, at the junction  of the palatine processes  of the up-
per maxillary bones;  where a bony prominence is formed,
to which it is firmly united.  The upper part of the ante-
rior edge of this cartilage, which is in contact with the
ossa nasi, is flat, and  is continued into two lateral portions
that are extended  from it, one  on each  side, and form
a part of the nose: these lateral portions are sometimes
spoken of as distinct  cartilages;  but they are really con-
tinuations of the middle portion or septum.
  Below the lower edge of these lateral portions are situ-
ated the cartilages which form the orifices of the nose, or
the nostrils. Of these, there is one of considerable size,
and several small fragments, on each side of the septum.
Each of the larger cartilages forms a  portion  of an oval
ring, which is placed obliquely on the  side of the septum:
so that the extremity of the oval points downward and 
                     Of the Nose.                    3
forward, while the middle part of the oval is directed up-
wards and backwards. The sides of this cartilage are flat,
and unequal in breadth. The narrowest side is internal,
and projects lower down than the cartilaginous septum; so
that it is applied to its fellow of the other nostril. The ex-
ternal side is broader, and continues  backward and  up-
ward to a considerable distance.
   The upper and posterior part of this oval ring is defi-
cient; but the remainder of the nostril consists of several
small pieces of cartilage, which are fixed in a ligamentous
membrane that is connected by each of its extremities to
the oval cartilage, and thus completes the orifice.
   The anterior parts of the oval cartilages form the point
of the  nose; and the ligamentous portions,  the alae or
lateral parts of the nostrils.
   When the external integuments and muscles are  remo-
ved from the lower portion of the nose, so that the internal
membrane and  these cartilages only remain, the  inter-
nal membrane will be found attached to the whole bony
margin of each orifice, and to each  side of the whole ante-
rior edge of the middle cartilage, which projects beyond
the bones, so that it would close up these openings of the
nose, if it were not for the orifices formed by the oval
cartilages and the ligament above described; but being
attached to one edge only of these cartilages, the  orifice
formed by them is complete.
   The  internal portions of the oval cartilages being situ-
ated without the septum, and applied to each other, they
form the external edge of the partition between the nos-
trils, or the columna nasi; which  is very moveable upon
the edge of the middle cartilage.
   The orifices of the nostrils, thus constructed, are dilated
by that portion of the muscle, called Levator Labii Supe-
rioris Alaque Nasi, which is inserted into the alae nasi.
   They are drawn down by the depressor labii superioris 
4             Of the Cavities of the Nose.
alaeque nasi. They are pressed against the septum and the
nose by the muscle called Compressor 'Naris,  which has
however an opposite effect when  its upper  extremity is
drawn upwards  by those fibres of the occipito-frontalis,
which descend upon the nose, and arc in contact with it.
  The end of the nose is also occasionally drawn down,
by some muscular fibres which descend  from  it, on the
septum of the nose, to the orbicularis oris: they are con-
sidered as a portion of this muscle by many anatomists,
but were described by  Albinus as a separate muscle, and
called  Nasalis Labii Superioris.
  When inspiration takes place with great force, the alae
nasi would be pressed against the septum if they were not
drawn out and  dilated by some  of the muscles above
mentioned.
                    SECTION II.

              Of the Cavities of the Nose.
  TO the  description  of the  osseous parts of the nasal
cavities in vol. I, page  53, it ought now to be added that
the vacuity in the anterior part of the  osseous septum is
filled up by a cartilaginous plate,  connected with the na-
sal lamella of the ethmoid bone above, and with the vo-
mer below. This plate sends off those lateral portions al-
ready described, which form the cartilaginous part of the
bridge of the nose.
  It should also be observed  that at  the back parts of
these cavities are two orifices called the Posterior Nare$
which are formed by the palate bones, the vomer, and the
body of the sphenoidal bone, and  are  somewhat oval in
figure. 
Schneiderian Membrane.
5
  The nasal cavities, thus constructed, are lined by a pe-
culiar membrane, which is called pituitary from its secre-
tion of mucus, or Schneiderian after an anatomist who de-
scribed it with accuracy.*
  This membrane is very thick and strong, and abounds
with so many bloodvessels, that in the living subject it is
of a red colour.  It adheres to the bones and septum of the
nose like the periosteum, but separates from them more
easily.  The surface  which adheres to the bones has some
resemblance to periosteum; while the other surface is soft,
spongy, and rather villous.  Bichat seems  to have consi-
dered this membrane as formed of two laminae, viz: peri-
osteum, and the proper mucous membrane; but he  adds,
that it is  almost impossible to separate them.
  It has  been supposed that many  distinct glandular bo-
dies were to be seen in the structure of this membrane by
examining the surface next  to the bones;f  but this opi-
nion is adopted  by very few of the anatomists of the
present day. The texture of the membrane appears to be
uniform; and on its  surface are a great number of follicles
of various sizes, from which flows the mucus of the nose.
  These follicles appear like pits, made by pushing a pin
obliquely into a surface which retains the form of the im-
pression. They can be seen very distinctly with a common
magnifying glass when the membrane is immersed in wa-
ter, both  on the septum and on the opposite surface. They
are scattered over the membrane without  order or regu-
larity, except that in a few places they occur so as  to form
lines of various lengths, from half an inch to an inch. The
largest of them  are in the lower parts of the cavities.
  It may be presumed that the secretion of mucus is ef-

  * Conrad Schneider, a German professor, in a  large  work, " De
Catarrhis," published about 1660.
  t See Winslow, section X. No. 337. 
6                 Olfactory Nerves.
fected here by vessels which are mere continuations of ar-
teries spread upon a surface analogous to the exhalents,
and not convoluted in  circumscribed masses, as in the
case of ordinary glands.
  The arteries of this membrane are derived from various
sources: the most important of them is the nasal branch
of the  internal maxillary, which  passes  into the  nose
through the spheno-palatine  foramen, and is therefore
called the  Spheno-palatine Artery.  It divides into several
twigs, which are spent  upon the different parts of the sur-
face of the nasal  cavities. Two  of them are generally
found on the septum of the nose: .one, which is small,
passes forwards near the middle; the other, which is much
larger,  is near the lower part of it.
  Two small  arteries  called  the  anterior and posterior
ethmoidal, which are branches of the ophthalmic, enter the
nose by foramina of the cribriform plate of the ethmoidal
bone. These arteries pass from the orbit  to the cavity of
the cranium, and then through the cribriform plate to the
nose. In addition to these, there are some small arteries
derived from the infra orbital,  the alveolar and the  pala-
tine, which extend to the Schneiderian membrane; but they
are not of much  importance.
  The veins of  the nose correspond  with the arteries.
Those which accompany the ethmoidal arteries open into
the ocular vein of the orbit, which terminates in the ca-
vernous sinuses of the  head. The other veins ultimately
terminate in the  external jugulars.
   The nerves of the nose form an important part of the
structure: they are  derived from several sources; but the
most important branches are those of the olfactory.
   The olfactory nerves form oblong bulbs, which lie on
each side of the  crista  galli, on the depressed portions of
the cribriform plate of the ethmoid bone, within the dura
mater.  These bulbs are  of a soft consistence, and resem- 
                  Olfactory Nerves,                 7

ble the cortical part of  the brain mixed with streaks of
medullary matter. They send off numerous filaments,
which pass through the foramina of the ethmoid bone, and
receive a coat from the dura mater as they pass through it.
  These filaments are  so arranged  that they form two
rows, one running near to the septum, and the other to
the surface of the cellular part of the ethmoid bone, and
the os turbinatum: and  in addition to these are some in-
termediate filaments.
  When the  Schneiderian membrane is peeled from the
bones to which it is attached, these nervous filaments are
seen passing from the foramina of the ethmoid bone to
the attached surfaces: one row  passing  upon that which
covered the septum, and the other to that of the opposite
side; while the intermediate filaments take an anterior di-
rection, but unite to the membrane as soon as they come
in contact with it.
  All of these can be traced downwards on the aforesaid
surfaces of the membrane  for a considerable distance,
when they gradually sink into  the substance of the mem-
brane, and most probably terminate on the internal vil-
lous surface;  but  they have  not been traced to their ulti-
mate termination. They ramify so that the branches form
very acute angles with  each other. On the  septum the
different branches are arranged so as to form brushes,
which lie in  contact with  each other. On the opposite
sides, the different ramifications unite so as to  form a
plexus.
   Dr. Soemmering published  last  year some very ele- '
gant engravings of the nose, representing one of  his dis-
sections,  which   appears to have been  uncommonly mi-
nute and successful.* These represent the ramifications
as becoming  more expanded and delicate in the progress

   * They are intitled, Icones organorum humanorum olfactus. 
 8    Spheno-palatine and other Nerves of the Nose.
 towards their  terminations,  and as  observing a tortuous
 course, with very short meandering flexures.
   It is to be observed that the ramifications of the olfac-
 tory nerve, thus arranged, do not extend to the bottom of
 the cavity. On the external side, they are not traced lower
 than the lower edge of the ethmoid, or of the superior
 spongy bone:  and on the septum, they do not extend to
 the bottom, although they are lower than on the opposite
 side. On the parts of the membrane not occupied by  the
 branches of the olfactory nerve, several other nerves can
 be traced. The nasal twig of the ophthalmic branch of the
 fifth pair, after passing from the orbit into the  cavity of
 the cranium, proceeds to the nasal cavity on each side by
 a foramen of the cribriform plate; and after sending off
 some fibrillae,  descends upon the anterior part of the sep-
 tum to the point of the nose. The spheno-palatine nerve,
 which is derived from the second branch of the  fifth pair,
 and enters the nose by  the  spheno-palatine  foramen, is
 spread upon the lower part of the septum and of the oppo-
 site side of the nose also, and transmits a branch through
 a canal in the foramen incisivum to the mouth. Several
 small branches also pass to the nose from the palatine and
 other nerves; but those already  mentioned are  the most
important.
   A question  has been  proposed, whether the  olfactory
nerve is exclusively concerned in the function of smelling,
or whether the other nerves above mentioned are also con-
cerned in it. It seems  probable that this function is  ex-
clusively performed by the olfactory nerve,  and that the
other nerves are  like  the ophthalmic branch of the fifth
pair, with respect to the optic nerve. In proof of  this, it is
asserted that the  sense of smelling has  entirely ceased in
some cases, where the sensibility to  mechanical  irritation
of every kind has remained  unchanged. If the  olfactory
nerve alone is  concerned in the  function  of smelling, it 
        Extent of the Schneiderian Membrane.       9

follows, that this function must be confined to the upper
parts of the nasal cavities; but it ought to be remembered,
that the structure of the Schneiderian  membrane, in the
lower parts  of these cavities,  appears exactly like that
which is above.
  The  surface of the  nasal cavities  and their septum,
when covered with the Schneiderian membrane, corres-
ponds with the osseous surface formerly described.  The
membrane covers the bones and cartilage of the septum,
so as to make one  uniform regular surface. From  the
upper part of the septum,  it is continued to  the under
side of the cribriform plate of the ethmoid, and lines it;
the filaments of the olfactory nerve  passing through the
foramina of that bone into the fibrous surface of the mem-
brane. It is  continued from  the septum, and from the
cribriform plate,  to the internal  surface of the external
nose, and lines it. It is also continued backwards to the
anterior surface of the body of the sphenoidal bone; and,
passing through the foramina or openings of the sphe-
 noidal  cells, it lines these cavities completely;  but in
 these, as  well as the other  cavities, its structure appears
 somewhat changed: it becomes thinner and less vascular.
   At the above mentioned foramina,  in some subjects, it
 forms a plait or fold, which diminishes the aperture con-
 siderably.
    From the upper  surface of the nasal cavities, the mem-
 brane is continued  downwards over the  surface opposite
 to the septum.  On the upper flat surfaces of the cellular
 portions  of the  ethmoid, it forms a smooth uniform, sur-
 face.  After passing over the first turbinated bone, or that
 called after Morgagni, it is reflected into the groove, or
 upper meatus, immediately within  and under  it:  the fold
 formed by  the membrane, as it is reflected into the mea-
 tus, is rather larger than the  bone; and the edge of  ths
 fold therefore extends lower down than the edge qf  the
    Vol. II.              B 
10    Distribution of the Schneiderian Membrane.
bone, and partly covers the meatus like a flap, consisting
only of the doubled membrane. This fold generally con-
tinues backwards as far as the spheno-maxillary foramen,
which it closes; the periosteum, exterior to the foramen,
passing through it,  and blending  itself with the fibrous
surface of the Schneiderian membrane within. Here the
spheno-palatine nerves  and arteries join the membrane.
Below this meatus, it extends over the middle  (formerly
called the upper) turbinated bone,  and is reflected or fold-
ed inwards on the under side of this bone, and continued
into the middle  meatus below it.  In the middle meatus,
which is partly covered by the last mentioned turbinated
bone, there are  two foramina: one communicating with
the maxillary sinus; and the other  with the anterior cells
of the ethmoid and the frontal sinuses. The aperture into
the maxillary sinuses is much less in the recent head, in
which the Schneiderian membrane lines the nose, than it
is in the bare bones.  A portion  of the aperture in the
bones is closed  by the Schneiderian membrane, which is
extended over it: the remainder of the aperture is unclos-
ed;  and through this foramen, the  membrane is reflected
so as to line the whole cavity. As a portion of the fora-
men is covered  by the membrane,  and this portion as well
as the other parts of the cavity is lined by the membrane,
it is obvious that at the place where the membrane is ex-
tended over the foramen in the bone, it must be doubled;
or,  in other words, a part of the aperture of the maxillary
sinus is closed by a fold of the Schneiderian membrane.
  This aperture varies in size in different subjects, and is
often  equal in diameter to a common quill.  It is situated
in the middle meatus, and is covered by the middle turbi-
nated bone: immediately above it, is a prominence of the
cellular structure of the ethmoid bone, which has a curved
or semicircular figure. Near this prominence, in the same 
   Eustachian Tube.-Observations respecting the Nose. 11

meatus, a groove terminates, which leads from the anterior
ethmoid cells and the frontal sinuses.
   From the middle meatus, the membrane proceeds over
the inferior turbinated bone, and is reflected round and
under it into the lower meatus. It  appears  rather  larger
than the bone which  it covers; and therefore the lower
edge of the bone does not extend so low as the lower edge
of the membrane, which of course is like a fold  or plait.
The membrane then continues and lines the lower meatus:
here it appears less full than it is in the turbinated bone.
In this meatus, near to its anterior end,  is the lower orifice
of the lachrymal duct: this is simply lined by the Schnei-
derian membrane, which is continued  into it, and forms
no plaits or folds that affect the orifice.

            Orifice of the Eustachian  Tube.
   Immediately behind each of the nasal cavities, on the
external side,  is the orifice of the Eustachian Tube. It has
an oval form,  and is large enough to admit a very large
quill. Its position is oblique; the upper extremity being
anterior to the other parts of the aperture,  and on a line
with the middle meatus,  while the center is  behind the
inferior turbinated bone. The lower part  of the oval is
deficient. This tube is formed posteriorly by a cartilagi-
nous plate. It is lined by the membrane continued from
the nose.

    The cavities of the nose answer a twofold purpose in the ani-
      mal economy:  they afford a  surface for the expansion
      of the olfactory nerves; and a passage for the external
      air to the windpipe, in respiration.
    The function of smelling appears to be dependent, to a
      certain  degree, upon respiration. It has been asserted
      that unless the air passes in a stream through the nose,
      as in respiration, the perception of odour does not take
      place; that in persons who breathe through  wounds and 
12          Use of the Sinuses of the Nos&.

      apertures  in the  windpipe, the function of smelling id
      not performed. It is rather in confirmation of this pro-
      position, that most persons, when they wish to have an
      accurate perception of any odour, draw in air rapidly
      through the nose.
    Although the ultimate termination of the olfactory  nerve
      cannot be demonstrated like those of the optic and au-
      ditory nerves, it is probable, from the appearance of the
      fibres, while they are distinguishable, that they are fi-
      nally arranged  with great delicacy. It is  certain that
      the  impressions from whence we derive the perception's
      of many odours must be very slight; as some odorous
      bodies will impregnate the air of a large chamber, for a
      great length of time, without losing any sensible weight.
    With respect to delicacy of structure and  sensibility, it is
      probable that the nose holds a middle rank  between the
      eye  or ear, and  the tongue:  and on this  account the
      mucus is necessary as a covering and  defence of its
      surface.
   It has  been ascertained, by the investigations of chemists,
      that this mucus  contains  the same ingredients as the
     tears already described, viz: animal  mucus and water;
     with muriate of soda, and soda uncombined; phosphate
     of lime, and phosphate of soda.
   The animal mucus, which is  a most important ingredient
     in the composition, resembles the mucilage  formed by
     some of the vegetable gums in several particulars; an'd
     differs from them in others.
   The mucus of the nose, if it remain there long after it /is
     secreted, becomes much more viscid in consistence, and
     changes from  a whitish colour  to one which partakes
     more or less of the yellow. It is probable that an inci-
     pient putrefaction  may occasion these changes in it.
   The use of the frontal, maxillary and other  sinuses, com-
     municating with the nose, has been the subject of some
     inquiry.  As there  can be no stream of air through them
      and  as the membrane lining them is neither so thick'
      ViUous nor flexible as that lining the nose,it may be cot
      eluded, a prion, that they are not concerned in the funs- 
       Use of the Sinuses of the Nose.          13

 tion of smelling. This opinion  is strengthened by the
 fact, that very young  children, in whom these sinuses
 scarcely exist, enjoy the sense of smelling in perfection.
 The following fact is also in support of it. The celebrated
 Dessault attended a patient, in whom one  of  the frontal
 sinuses was laid open by the destruction of the  bone
 which covered it anteriorly. This  patient was  able to
 breathe a short time through the sinus when the mouth
 and nose were closed: At the request of Dessault he
 breathed  in this manner when a cup  of some aromatic
 liquor was held near the opening of the  sinus: and had
 not the least perception of odour. This  experiment was
 repeated several times.
Many physiologists believe that these sinuses have an ef*
  feet in modulating  the voice. 
14
                    CHAPTER II.

                   OF THE MOUTH.

THE general cavity of the mouth is  formed anteriorly
and laterally by the connexion of the lips and checks to
the upper and lower jaws; so that the teeth and the alveo-
li of both jaws may be  considered as within the cavity.
Above, it is bounded principally by  the palatine process-
es of the upper maxillary and palate bones, and the soft
palate, which continues backward from them in the same
direction. Below, the cavity is completed by several mus-
cles, which proceed from almost the whole internal cir-
cumference  of the lower jaw, and,  by their connexions
with each other, with the tongue and the os hyoides, form
a floor or bottom to it. The tongue is particularly connect-
ed to this surface, and may be considered as resting upon
and supported by it.
  To acquire an idea of the parietes of this cavity, after
studying the upper and lower maxillary bones, the orbi-
cularis oris and the muscles connected with it, especially
the buccinator, ought to be examined; and also the digas-
tricus, the  mylo-hyoideus,  genio-hyoideus, and  genio-
hyoglossus.  By this it will appear that the lips and cheeks,
and the basis or floor of the mouth,  are formed in a great
measure by  muscles. Upon the internal surface  of these
muscles, a portion of cellular and adipose substance is ar-
ranged, as well as glandular bodies of different sizes; and
to these is attached the membrane which lines the inside
of the mouth.
   This membrane passes from the skin of the face to the
lips, and the inside of the mouth; and, although it is really
a continuation of the skin,  there is  so great a change of 
           Internal Surface of the Mouth.          15
structure, that it ought  to be considered  as  a different
membrane. At the orifice of the lips it is extremely thin,
and so vascular that it produces the fine florid colour which
appears there in  health. It is covered by a cuticle, called
by some anatomists, Epithelium, which  has a proportion-
ate degree of delicacy, and can be separated like the cu-
ticle in  other  parts. When  this cuticle is separated, the
lips and  the membrane of the mouth,  appear  to be co-
vered with very fine villi, which are particularly apparent
in some preparations of the lips after  injection and ma-
ceration.*
   Under this membrane  are many small glandular bodies
of a roundish form, whose excretory ducts pass through it
to the inner surface of the mouth, for the  purpose of lubri-
fying it with their secretion, which is mingled with the
saliva.
   The membrane, which lines the inside of the lips and
cheeks, is somewhat different from that which forms the
surface of the  orifice of the mouth: it is  not so florid; the
bloodvessels in its texture are larger and  not so numerous.
This change, however, takes place very gradually, in the
progress of the membrane, from the orifice of the lips to
the back part of  the cheeks. Glandular bodies, like those
of the lips, are situated immediately exterior to this mem-
brane of the cheeks, between it and  the muscles:  their
ducts open on its surface. These glands are called Buc-
cales.
   This lining membrane is continued from the internal
surface of the lips and cheeks  to the alveolar portions of
the upper and lower jaws, which  are  in the cavity of the
mouth, and covers them, adhering firmly to the perios-
teum.
   The teeth appear to have passed through apertures in

   * Ruysch had a  fine preparation  ef this structure. See Thesau*
rus VII. Tab. III. Fig. 5. 
 16       Gums.—Surface of the Hard Palate.
 this membrane, and are surrounded by it closely at their
 respective necks.
   The portion of membrane, which thus invests the jaws,
 constitutes the gums; which have now acquired a texture
 very different from that of the  membrane,  from which
 they were continued. They are extremely firm and dense,
 and very vascular. It is probable that their ultimate struc-
 ture is not perfectly understood.
   In the disease called scurvy, they tumify and lose the
 firmness of their texture: they acquire a livid colour, and
 are much disposed to  hemorrhage.
   From the alveoli of the upper jaw, the lining membrane
 is continued upon the palatine processes of the upper max.
 illary and palate bones, or the roof of  the mouth.
   This membrane of the palate is not quite  so firm as
 that of the gums, and  is also less florid: it adheres firmly
to the periosteum,  and thus is closely  fixed to the bones.
 There is generally  a ridge on its surface, immediately un-
 der the  suture between the two  upper maxillary bones;
 and some transverse ridges are also to be seen upon it.
 On the  internal surface of this membrane are small glan-
 dular bodies, whose ducts open on the surface of the pa-
 late.
   It is asserted, that this membrane has a limited  degree
 of that sensibility which is essential to the function of tast-
 ing; and, that if certain  sapid substances are carefully
 applied to it,  their  respective  tastes will be perceived,  al-
 though they have not been in  contact with the tongue.
   The  membrane is  continued  from the bones above
 mentioned to the soft palate,  or  velum pendulum palati,
 which is situated immediately behind them. This soft pa-
 late may be considered as a continuation of the partition
 between the nose and mouth: it is attached to the posterior
 edge of the palatine processes of the ossa palati,  and to
 the pterygoid processes of the sphenoidal bone.  Its in- 
Soft Palate.—Uvula.
17
terior structure is muscular. The upper surface is cover-
ed by the membrane of the nose, the lower surface by
the membrane which lines the mouth.
  The muscles, which contribute to the  composition of
this structure, are the circumflexus and the levatores palati
above, and the constrictores isthmi  faucium and palato-
pharyngei below. (See Vol. I.  page 178—179.) Thus
composed, the soft palate constitutes the back part of the
partition  between  the  nose and mouth.  When  viewed
from before, with the  mcuth open, it presents towards
the tongue an arched surface, which continues downwards
on each side until it comes nearly  in contact with  the
edges of that organ. On each of the lateral parts of this
arch, are two pillars, or rather  prominent ridges, which
project into the mouth.  These ridges are at some distance
from each other below, and approach much nearer above,
so that they include a triangular space.  They are called
the lateral half arches of the palate. Each of them is form-
ed by a plait or fold of the  skin, and contains one of  the
two last  mentioned muscles: the  anterior, the constric-
tor isthmi faucium; the posterior, the palato-pharyngeus.
These muscles, of course, draw the  palate down toward
the tongue when they contract.
   From the center of the arch, near  its posterior edge, is
suspended the uvula, a  conical body, which varies in
length from less than half an inch to rather more than  one
inch. It  is connected by its basis  to the  palate;  but its
apex is loose and pendulous. This body is covered by the
lining membrane of the mouth. It  contains many small
glands, and a muscle also, the azygos uvulae, which  ari-
ses from the posterior edge of the ossa palati, at the su-
ture which connects them to  each other, and, passing
posteriorly upon the soft palate, extends  from the basis
to the apex of the uvula, into which it is inserted. By the
the action of this muscle, the length of the uvula can be
   Vol. II.                C 
18                   The Tongue.
very much diminished; and when its  contraction ceases,
that body is elongated.
  The pendulous part of the uvula can also be moved, in
Certain cases, to either side.
  It is commonly supposed, that the principal use of this
little organ is to modulate the voice;  but there are good
reasons for believing, that it has another  object. It was
remarked by Fallopius, (and the observation has been con-
firmed by many surgeons since his time) that the uvula
may be removed completely without occasioning any alter-
ation of the voice, or any difficulty in deglutition, if the
soft palate be left entire.
  The soft palate is so flexible, that it yields to the actions
of the levatores palati, which draw it up so as to close the
posterior nares completely.
  It also yields to the circumflexi or tensores, which stretch
it so as to do away its arched appearance.
  It is therefore very properly called the Palatum Molle.
It is also frequently called the Velum Pendulum palati,
from the position which it assumes.

                     The Tongue,
  Which is a very important part of this structure, is re-
tained in its position and connected with the parts adjoin-
ing it, by the following arrangements.
  The os hyoides, which, as its name imports, resembles
the Greek letter u, or half an oval, is situated rather below
the angles of the lower jaw, in  the middle of the upper
part of the neck. It is retained in its position  by the ster-
no-hyoidei muscles, which connect it to the upper part
of the sternum; by the coraco-hyoidei, which pass to it
obliquely from  the scapula; by  the thyro-hyoidei, which
pass to it directly upward from the  thyroid cartilage: all
of which connect it to parts below.  To these should be
added the stylo-hyoidei,  which pass  to it obliquely from 
               Structure of the Tongue.             19

 behind and rather from above; the mylo-hyoidei, which
 come rather anteriorly from the lateral parts of the lower
 jaw; and the genio-hyoidei, which arise  from a situation
 directly  anterior and  superior,  the  chin.  When  these
 muscles are at rest, the situation of the  os hyoides is, as
 above described, below the angles of the lower jaw: when
 those, in one particular direction, act while the others are
 passive, the bone may  be moved upwards or downwards,
 backwards or  forwards, or to either side. This bone may
 be considered as the basis of the tongue; for the posterior
 extremity of that organ is attached to it; and of course
 the movements of the  bone  must have an immediate ef-
 fect upon those of the tongue.
   The tongue is a flat  body of an oval figure, but subject
 to considerable changes of form.
   The posterior extremity, connected to the  os hyoides,
 is commonly called its basis; the anterior extremity, which
 when the tongue is quiescent, is rather more acute,  is
 called its apex.
   The lower surface of the tongue is connected with a
 number  of muscles, which are continued into its sub-
 stance. This  connexion  is such, that the edges of the
 tongue are perfectly free and unconnected; and so is the
 anterior extremity for a  considerable  distance from the
 apex towards the base.
   The substance of the  tongue consists principally  of
 muscular fibres intermixed with a delicate adipose sub-
 stance. It is connected to the os hyoides by the hyoglos-
 sus muscle and also by some  other muscular fibres, as
 well as by a dense membranous substance, which appears
 to perform the part of a ligament. This connexion is also
 strengthened by the continuance of the integuments from
 the tongue to the epiglottis cartilage,  to  be hereafter de-
scribed; for that cartilage is attached by ligaments to the
os hyoides. 
 20             Structure of the Tongue.

   The tongue is thin at its commencement at the os hy-
 oides; but it soon increases in  thickness. The muscular
 fibres in its composition have been considered as intrinsic,
 or belonging wholly to its internal structure; and extrinsic,
 or existing in part outside of this structure. The linguales
 muscles are intrinsicr (Vol I, page 175.) they  are situa-
 ted near the under surface of the tongue, one on each side,
 separated from each other by the genio-giossi muscle, and
 extending from the basis of the tongue to its apex. These
 muscles can be easily  traced as  above  described; but
 there are also many fibres in the structure of the tongue,
 which seem to  pass in every direction, and of course are
 different from those of the linguales  muscles.  To these
 two sets of fibres are owing many of the immensely varied
 motions of the different parts of the tongue.
   In  addition to these, are the  extrinsic  muscles, which
 originate from the neighbouring  parts, and are inserted
 and continued into the substance of the tongue.
   Among the most important of these muscles, are those
 which proceed from the chin,  or the  genio-hyoglossi.
 They are in contact with each other; their  fibres  radiate
 from  a central point  on  the inside of the chin, and are
 inserted into the middle of the lower surface of the tongue:
 the insertion commencing  at a short distance  from its
 apex, and continuing to its base.
   As the genio-hyo-glossi  muscles have a considerable
 degree of thickness,  they add  much  to  the bulk of the
 tongue in the middle of the posterior parts of it.
   The hvo-glossi and the stylo-gloss!, being continued
 into the posterior and lateral parts, contribute also to the
 bulk of these parts.
   The tongue,  thus composed and connected, lies, when
 at rest, on the mylo-hyoidei muscles; and the space be-
 tween it and  these muscles is  divided into two  lateral
parts  by the above described genio-glossi. In the space 
                PapilU of the Tongue.              21

above mentioned, is a small salivary gland, of an irregular
oval form; the greatest diameter of which extends  from
before backwards; and its edges present outwards and in-
wards. It has several excretory ducts, the orifices of which
form a line on each side of  the  tongue.  This gland is
very prominent under the tongue; and when the tongue
is raised it is particularly  conspicuous:  it is called  the
Sublingual.
   The lining membrane of the  mouth  continues  from
the inside of the alveoli of the lower jaw, which it covers,
over the sublingual glands to the  lower surface of the
tongue.  In this situation it is  remarkably thin; but, as it
proceeds to the upper surface  of the tongue, its texture
changes considerably; and on this surface  it constitutes
the organ of taste.
   The upper surface of the tongue, although it is con-
tinued from the thin membrane above described, is form-
 ed by a rough integument which consists, like the skin,
 of three laminae.  The cuticle is very  thin;  and  under
 it, the rete mucosum* is thicker and softer than in other
 places.
    The true skin here abounds with eminences of various
 sizes  and forms, all of which  are  denominated Papillte.
 The largest of these are situated on the posterior part of
 the tongue,  and are so arranged that they form an angle
 rather acute, with its point backwards.  They are com-
 monly nine  in number:  they resemble an inverted cone;
 or, are  larger at their head  than  their basis.  They are
 situated in pits or depressions, to the bottoms of  which
 they are connected. In  many of them there are follicles,
 or perforations, which have occasioned them to  be re-

    * M. Bichat appears to have had doubts whether the real rete mu-
 cosum existed here. He says that he could only perceive  a decus-
 sation of vessels in the intervals of the papillae, which, as he supposes,
 occasioned the florid colour of the tongue. 
 22               Papilla of the Tongue.

 garded as glands.  They are called Papilla:  Maxima, or
 Capitata.
   The papilla?, next in size, are denominated fungiform
 by some anatomists,  and Media or Semilenticulares by
 others. They are  nearly cylindrical in form, with their
 upper extremities regularly rounded. They arc scattered
 over the upper surface of the tongue, in almost every part
 of it, at irregular distances from each other.
   The third  class  are called conoidal or villous.  They are
 very numerous, and occupy the greatest part of the sur-
 face of the tongue. Although  they are called conoidal,
 there is a great difference  in their form;  many of them
 being irregularly angular and serrated, as well as conical.
   Soemmering and other  German anatomists consider
 the smallest papillae as a fourth class, which they call  the
filiform: these lie between the others.
   It is probable  that these papillae are essential parts of
 the organ of taste;  and their structure is of course an in-
 teresting  object of inquiry.
   The nerves of the tongue have been traced to the papil-
 lae, and have  been  compared by  some anatomists  to  the
 stalk of the apple, while the papillae resembled the fruit;
 but their ultimate  termination  does not appear  to have
 been ascertained.*
   Soemmering has lately published some elegant engraved
 copies of drawings of these papillae, when they were mag-
 nified twenty-five  times;  from  which  it  appears that a
 very large number of vessels, particularly of arteries, ex-

   * In the explanation of the plates, referred to in the following sen-
 tence, Soemmering observes, that when the fibrillae of the lingual
 nerve of the fifth pair are traced to the papillae of the second class,
-they  swell out into a conical  form; and these nervous cones are in
 such close contact with each other, that the point of the finest nee-
 dle could not be insinuated into the  papillae  without touching a
 nerve. 
Bloodvessels of the Tongue.           23
ist in them.  These vessels are arranged in a serpentine
direction, and are prominent on the surface; but they ap.
pear doubled, and the most prominent part is the doubled
end. This arrangement of vessels  is perceptible  on the
sides of the tongue, as well as on the papillae.
  Behind the large  papillae  is a foramen,  first described
by Morgagni, and called by him Foramen Cacum.  It is
the orifice of a cavity which is not deep; the  excretory
ducts of several mucous glands open into it.
  On the upper surface of the tongue, a groove is often
to be seen, which is called the linea mediana, and divides
it into two equal  lateral  parts. Below, the lining mem-
brane of the mouth, as it is continued from the lower jaw
to the tongue, forms a  plait,  which acts as a  ligament,
and is called the franum lingua. It is attached to the mid-
dle of the tongue, at some distance behind the apex.
  The tongue is well supplied with bloodvessels,  which
are derived from the lingual branch of the external carotid
on each side.  This artery passes from the external carotid,
upwards, inwards, and forwards, to the body of the tongue.
In this course it sends off several small arteries to the con-
tiguous parts, and one, which is spent about the epiglottis
and the adjoining parts, called the Dorsalis Lingua. About
the anterior edge of the hyo-glossus muscle, it divides into
two  large branches:  one of  which, called the Sublingual,
passes under the tongue  between the genio-glossus and
the sublingual gland, and extends  near to the symphysis
of the upper jaw;  sending branches  to the sublingual
gland, to the  muscles under the tongue, to the skin, and
the lower lip. The other is in the substance of the tongue,
on the under side near the surface, and extends to the apex.
  The veins  of this organ are not so regular as the arte-
ries: they communicate  with the  external jugular; and
some of them are always very conspicuous under the
tongue: these are  called ranular. 
24              The Salivary Glands.
  It is to be observed, that the vessels on each side have
but little connexion with each other; for those of one side
may be injected while the others continue empty.
  The tongue is also well supplied with nerves, and de-
rives them from three different sources on each side, viz.:
from the fifth, the eighth, and ninth pairs of the  head.
  The lingual portion of the third branch of the fifth pair,
passing under the tongue, enters its substance about the
middle, and forms many minute branches, which pass to
the papillae of the fore part of the tongue.
  The  glosso-pharyngeal portion  of the  eighth  pair,
sending off several  branches in its  course, passes  to the
tongue  near  its  basis, and  divides into   many  small
branches, which arc  spent upon the sides and middle of
the root of the tongue, and also upon  the large  papillae.
  The ninth pair of  nerves  are principally appropriated
to the tongue. They pass on each side to the most  fleshy
part of it, and after sending one branch to thevmylo-hyoi-
deus, and another to communicate with the lingual branch
of the fifth pair, they are spent principally  upon the ge-
nio-glossi, and linguales muscles.
  The  tongue answers  a threefold purpose. It  is the
principal organ of taste.  It is  a very important  agent in
the articulation of words; and it assists in those operations
upon our food, which are performed in the  mouth.

                The Salivary Glands.
   The salivary glands have such an intimate connexion
with the mouth that they may be  described with it.*
  There are three principal glands on each side: the  Paro-
tid, the Submaxillary and the Sublingual. They  are of a
whitish or pale flesh-colour,  and are composed of  many
small united masses or lobuli, each of which sends a small

  * For a general account of glands, see the appendix to this volume. 
          Parotid and Submaxillary Glands.        25

excretory duct to join similar ducts from the other lobuli,
and thereby form the great duct of the gland.
  The Parotid is much larger than the other glands. It
occupies a large portion of the vacuity between the mas-
toid process and the posterior parts  of the lower jaw. It
extends from the ear and the mastoid process over a por-
tion of the masseter muscle,  and from the zygoma to the
basis of the lower jaw.  Its name  is supposed to be de-
rived from two Greek words which  signify contiguity to
the ear. It is of a firm consistence.  It receives branches
from the external carotid artery and from its facial branch.
   From the anterior edge of this gland, rather  above the
middle, the great duct proceeds anteriorly across the mas-
seter muscle; and, after it has passed over it, bends inward
through the adipose matter of the cheek to the buccinator
muscle,  which  it perforates obliquely and opens on the
inside of the cheek opposite to the interval between the
second and third molar teeth of the upper jaw.  The aper-
ture of the duct is rather less than the general diameter of
it, and this circumstance has the effect of a valve. When
the duct leaves the parotid, several small glandular bodies
are often attached to it, and  their  ducts  communicate
with it. The main duct is sometimes called after Steno,
who first described it.
   When the mouth is opened wide, as in gaping, there
is often a jet of saliva from it into the mouth.
   The parotid gland furnishes the  largest proportion of
saliva.
   It covers  the nerve  called  Portio Dura, after it has
emerged from the foramen stylo-mastoideum.
   The second  gland is called the Submaxillary. It is
much  smaller than the parotid, and  rather round  in form.
It is situated immediately within  the  angle of the lower
jaw, between it, on the outside, and the tendon of the di- (
gastric muscle and the ninth pair of nerves internally. Its
Vol II.                  D 
26            Sublingual Gland.—Saliva.

posterior extremity is connected by cellular membrane to
the parotid gland; its anterior portion lies  over a part of
the mylo-hyoideus muscle; and from it  proceeds the ex-
cretory duct, which is of considerable length, and passes
betwen the mylo-hyoideus and the genio-glossus muscles
along the under and inner edge of the sublingual gland.
In this course the duct is sometimes  surrounded with
small glandular bodies, which  seem to be  appendices of
the sublingual gland.  It terminates under the tongue, on
the side of the fraenum linguae, by a small orifice which
sometimes forms a papilla.
  The orifice is often smaller  than the duct;  in conse-
quence of which, obstruction frequently occurs here, and
produces the disease called ranula.
  The sublingual gland, which has already been mention-
ed,  lies so that, when the tongue is turned up, it can be
seen protruding into  the cavity of the mouth, and co-
vered by the lining  membrane, which  seems to keep it
fixed in its place. It lies upon the mylo-hyoideus, by the
side of the genio-hyoideus; and is rather oval in form and
flat. Its greatest length is from before backwards; its po-
sition is rather oblique, one edge being  placed  obliquely
inwards* and upwards, and the other outwards and down-
wards. It has many short excretory ducts, which open by
orifices arranged in a line on  each side: they are discover-
ed  with  difficulty,  on account of their small  size, and
sometimes amount to eighteen or  twenty in  number. In
some few instances, this gland sends off  a single  duct,
which communicates with the duct  of  the submaxillary
gland.
  The salivary fluid  secreted  by  these glands  is inodo-
rous, insipid, and limpid, like water; but much  more vis-
cid, and of greater specific gravity. Water constitutes at
least four fifths of its bulk; and animal mucus one half of
its  solid contents.  It  also contains some albumen, and 
                  Motions of the Tongue.                2 7

several saline substances: as the muriate of soda, and the
phosphates of lime, of soda, and of ammonia.
   It is probable  that this fluid possesses a solvent power
with respect to the articles of food.
   There are small glandular bodies, situated between the
masseter and buccinator muscles, opposite to the last mo-
lar tooth of the upper jaw, whose nature is not well under-
stood:  they  are called Glandula Molares.

     The motions  of the tongue are very intelligible to a per-
       son who has a preparation of the lower jaw before him,
       with  the tongue in its natural situation, and the mus-
       cles, which influence  it, properly dissected.  Its  compli-
       cated movements will appear the necessary result of the
       action of those muscles upon it, and the os hyoides; and
       also upon the larynx, with which the  os hyoides is con-
       nected.  The muscular fibres of the tongue itself are also
       to be  taken into this  view, as they act a very important
        part.
     Although the tongue  appears very necessary, in a me-
        chanical point of view, to the articulation of many words,
        yet there are cases where it has been entirely deficient,
        in which  the parties, thus  affected,  have been able to
        speak very well in general, as well as to distinguish dif-
        ferent tastes.*
     The tongue  is  also a very delicate  organ of touch. We
        can perceive the form of the teeth, and the state of the
        surface of  the mouth, more accurately by the applica-
        tion of the tongue than of the fingers.

   • There is a very interesting paper on this subject, in the Memoirs
 of the Academy of Sciences for the year 1718, by Jussieu;, in which
 he describes  the case of a  female, fifteen  years old, examined by
 himself, who was born without a  tongue. In this paper he refers to
 another case, described by Rolland, a surgeon of Saumur, of a boy
 nine years old, whose tongue was destroyed by gangrene. In each
 of these cases the subject was able to articulate very well, with the
 exception of a few  letters: and also enjoyed the sense of taste. 
28             Observations on the Tongue.
Of the three nerves which go to the tongue, it is generally
  supposed that the lingual portion of the third branch of
  the fifth pair is most immediately concerned in the func-
  tion of tasting, as it passes to the front part of the sur-
  face of the tongue.  The glosso-pharyngeal are probably
  concerned  in the same function on the posterior part,
  while the ninth pair of nerves seems  principally  spent
  upon the muscular parts of the organ.
It is obvious that the  tongue is most copiously supplied
  with nerves. This probably accounts for the great faci-
  lity of its motions, and the power of continuing them. 
29
                   CHAPTER III.
                   OF THE THROAT.

TO avoid circumlocution, the word throat is used as a
general term to comprehend the structure which occurs
behind the nose and mouth,  and above the oesophagus
and trachea. This structure consists,
  1st, Of the parts immediately behind the mouth, which
constitute the Isthmus of the Fauces:
  2d, Of the parts, which form the  orifice of the wind-
pipe, or the Larynx;—and
  3d, Of the muscular bag, which forms the cavity be-
hind the nose and mouth that terminates in the oesophagus,
or the Pharynx.
                    SECTION I.

             Of the Isthmus of the Fauces.
  In the back part of the mouth, on each side, are to be
seen the two ridges or half arches, passing from the soft
palate to the root of the tongue,  mentioned in page 17,
and  said to be formed by plaits of the skin  containing
muscular fibres.  The anterior plait, which contains the
muscle called Constrictor Isthmi Faucium, passes directly
from the side of the root of the tongue to the palate, and
terminates near the commencement of the uvula.  The
posterior plait runs from the palate obliquely downwards
and backwards, as it contains the palato-pharyngeus mus-
cle, which passes from  the  palate to the upper and pos-
terior part of the thyroid cartilage. 
30               Tonsils.—Epiglottis.
  In the triangular space between these ridges is situated
a glandular  body, called the  Tonsil or Amygdala. This
gland has an oval form, its longest diameter extending
from above downwards. Its surface is rather convex, its
natural colour is a pale red. On its surface are  the large
orifices of many cells of considerable size,  which exist
throughout  the  gland.  These  cells often communicate
with each other, so  that a probe can be passed  in at one
orifice and out at the other.
  Into these cells open  many mucous ducts, which  dis-
charge the mucus of the throat, for the purpose of lubri-
cating the surface,  and  facilitating the transmission of
food.
  The epiglottis, or fifth cartilage of the larynx, is situa-
ted at the root of the tongue, in the middle, between the
tonsils.  The part which is in sight is partly oval in form,
and  of  a whitish colour.  Its position, as  respects the
tongue, is nearly perpendicular, and its anterior surface
rather convex.
  The membrane continued from the  tongue over the
epiglottis is so  arranged that it forms a plait, which ex-
tends from the middle of the root of the tongue along the
middle of the anterior surface  of the epiglottis, from its
base upwards.
   On each  side of  this plait, or fraenum,  at the junction
 of the surfaces of the tongue and of the epiglottis, there
 is often a depression,  in which small  portions of  food
 sometimes  remain; and a small fraenum, similar to that
 above described, is sometimes seen on the outside of each
 of these cavities.
   The epiglottis is situated immediately before the open-
 ing into the larynx.
   The above described parts  can be well ascertained in
 the living subject,  by a person who has a general know-
 ledge of the structure.  Thus,  looking into the mouth, 
                   Of the Larynx.                 31
with the tongue depressed,  the uvula and soft palate are
in full view above, and the epiglottis is very perceptible
below; while the two ridges or lateral half-arches can be
seen on each side, with the tonsil between them.
                    SECTION II.

                   Of the Larynx.
  IN this structure are five cartilages, upon which  its
form and strength depends, viz: the Cricoid, the Thyroid,
the two Arytenoid, and the Epiglottis. These cartilages
are articulated to each other, and are supplied with mus-
cles by which certain limited motions are effected.
  The basis of the structure is a cartilaginous ring, called
the cricoid cartilage, which may be considered as the com-
mencement of the  windpipe.
  It may be described as an irregular section of a tube:
its lower edge, connected with the windpipe, being nearly
horizontal when the body is erect; and  the upper edge
very oblique, sloping  from before, backwards  and  up-
wards: in  consequence of this, it has but little depth be-
fore, but is eight or nine lines deep behind.
  The Thyroid cartilage is a  single plate, bent in such
manner that it forms an acute angle  with two similar
broad surfaces on each side of it.  It is so applied to the
cricoid cartilage, that the lower edge of the  angular part
is at a small distance  above the front part  of that car-
tilage,  and  connected  to it by ligamentous membrane:
while its broad sides are applied to it laterally, and thus
partially inclose it.
  The upper, edge of the ajigular part of the thyroid car-
tilage forms a notch; and the natural position of the carti- 
32        Arytenoid Cartilages  and Ligaments:
lage is such, that this part is very prominent in the neck:
it is called the Pomum Adami.
  Both the upper and lower edges of the thyroid cartilage
terminate posteriorly in processes, which are called Cor-
nua. The two uppermost are longest: they are joined by
ligaments to the extremities of the os hyoides. The lower
and shorter  processes  are fixed  to the cricoid cartilage.
The thyroid cartilage,  therefore, partly  rests upon the
cricoid cartilage below, and is attached to the os hyoides
above. It is influenced by the muscles which act upon the
os hyoides, and also by  some muscles which are inserted
into itself. It is moved obliquely downwards and forwards,
in a slight degree, upon the cricoid cartilage by a small
muscle, the  crico-thyroideus, which arises from that car-
tilage and is inserted into it.
  The Arytenoid cartilages are two small bodies of a tri-
angular pyramidal form, but slightly curved backwards.
They are placed upon the upper and posterior edge of the
cricoid cartilage, near to each other; and their upper ends,
taken together, resemble the mouth of a pitcher or ewer;
from which  circumstance their name is  derived. Their
bases are broad; and on their lower surfaces is  a cavity,
which corresponds with the convex edge of the  cricoid
cartilage,  to  which they are applied.  At these  places, a
regular  moveable articulation is formed,  by a capsular
ligament between each of these cartilages and the thyroid;
in consequence of which they can be inclined backward or
forward, inward or outward.
  From the anterior part of each of these cartilages, near
the  base, a tendinous cord passes forward, in a direction
which is horizontal when the body is erect, to tlve internal
surface of the angle of the thyroid.  These ligaments are
not  perfectly parallel to each other; for they are nearer be-
fore than behind.  The aperture between them is from two
to five lines  wide when the muscles are not in action; and 
                      Epiglottis.                    33

 this aperture is the orifice of the windpipe: for the exte.
 rior space, between these ligaments and the circumference
 of the cricoid, is closed  up by membrane and muscle. At
 a small distance  above  these ligaments are two  others,
 which also pass from the arytenoid to the  thyroid carti-
 lages. They are not so tendinous and distinct as the first
 mentioned, and cannot be drawn so  tense by the muscles
 of the  arytenoid cartilages.  They are also situated at a
 greater distance  from each  other, and thus form  a large
 aperture.
   On the external side of the upper  extremity  of each of
 the arytenoid  cartilages,  and nearly in contact with it, is a
 small cartilaginous  body, not so large as a grain of wheat,
 and nearly oval in form.  These are connected  firmly to
 the arytenoid  cartilages,  and are called their appendices.
 Being in the margin of the aperture of the larynx,  they
 have an effect upon its form.
   The  arytenoid cartilages  are  the posterior parts of the
 larynx: the Epiglottis, which has already been mentioned,
 is the anterior. When this cartilage is divested of its mem-
 brane, it is oval in its upper extremity,  and  rather angular
 below, terminating  in a long narrow  process which is like
 the stalk of a leaf. It is firmly attached  to the internal surface
 of the angular part  of the thyroid by this lower process;
 and, being placed in a perpendicular position, one of its
 broad  surfaces is anterior towards  the tongue, and the
 other posterior, towards  the opening of the windpipe.
   It is attached to the os hyoides by dense cellular texture
 or ligament, and to the tongue by those plaits of the mem-
 brane of the mouth, which have been  already described.
   It is elastic,  but more flexible than  the other cartilages;
 being somewhat different in  its  structure.  Its surface  is
 perforated by the  orifices of many mucous ducts.
   1 here is a small space between the  lower part of this
cartilage which is posterior, and the upper part of the thy-
roid and the ligament passing from  it to the os hyoides,
   Vol. II.               E 
34
Rima Glottidis.—Glottis.
 which are anterior. In this is a substance, which appears
 to consist of glandular and of adipose matter. It is suppo-
 sed that some of the orifices on the lower part of the epi-
 glottis communicate with this substance.
   In the erect position of the body, the epiglottis is situa-
 ted rather higher up than the arytenoid cartilages, and at
 the distance of ten or twelve lines from them.
  The membrane which covers the epiglottis, is extended
 from each side of it to the arytenoid cartilages; and being
 continued into the cavity of the larynx, as well as upon the
 general surface of the throat, it  is necessarily doubled:
 this doubling forms the lateral margins of the orifice of the
 cavity  of the larynx. In these folds of the membrane are
 seen very delicate muscular fibres, called the Aryteno-epi-
 glottidei.
  The membrane continues  down the cavity of the la-
 rynx, and, covering the upper ligaments, penetrates into
 the vacuity between them and the lower ligaments, so as
to form a cavity  on each side of the larynx, opening be-
tween the two ligaments, which is called  the Ventricle of
 Morgagni. The shape of these cavites is oblong. Its great-
 est length extends from behind forward,  on each side of
the opening into the windpipe formed by the two  lower
 or principal ligaments; so that when the larynx  is re-
 moved from the subject, upon looking into it from above
 you perceive three apertures: one in the  middle, formed
 by the two lower ligaments; and one on each  side of it,
 between the lower and upper ligament, which is the ori-
 fice of the ventricle of Morgagni.
  The aperture between the two lower ligaments is called
 the Rima Glottidis, or Chink of the Glottis; the upper aper-
 ture, formed by the fold of the membrane extending from
 the epiglottis to  the arytenoid cartilages, may  be termed
 Glottis.
  If the windpipe is divided near the larynx, and the la-
 rynx inverted, so that the rima glottidis may be examined 
Arteries and Nerves of the Larynx.        35
from below, the structure  appears still more simple; it
resembles a septum fixed abruptly in the windpipe, with
an aperture in it of the figure of the rima glottidis.
  The anterior surface of the two arytenoid cartilages is
concave. This concavity is occupied in each by a glandu-
lar substance, which  lies between the  cartilage and the
lining membrane; and extends itself horizontally, covered
by the upper ligament of the glottis. The nature of these
bodies is not  perfectly understood; but they are supposed
to secrete mucus.
  The membrane, which  lines the cavity of the glottis,
being continued from the mouth and throat, resembles the
membranes which invest  those  parts. In  some  places,
where it is in close contact  with the cartilages, it appears
united with the perichondrium,  and acquires more firm-
ness and density.
  The general motions of the larynx are very intelligible
to those who  are acquainted with the muscles which are
connected with the thyroid cartilage, and which move the
os hyoides. They  take  place particularly in  deglutition,
and in some modifications of the voice; and also in vomit-
ing-
  The motions of the particular cartilages on each other
can also be well understood, by attending to the origin and
insertion of  the various small  muscles connected with
them. The most important of these muscles are the crico-
arytenoidei postici and laterales,  the thyreo-arytenoidei,
the arytenoidei obliqui, and the arytenoideus transversus.
The effects of  their actions appear to be the dilating or
contracting the rima ciottidis,  and relaxing or extending
the ligamcnts which form it.
  The arteries of the larynx are derived from two sources,
viz: the superior thyroid, or laryngeal  branch of the ex-
ternal carotid; and the thyroid branch of the subclavian.
  The nerves of the larynx also come to it in two very dif-
ferent directions on each side. It receives  two branches 
36                The Thyroid Gland.

from the par vagum: one which leaves that nerve high up
in the neck, and is called the Superior Laryngeal branch;
and  another which  proceeds from it after it has  passed
into  the cavity of the thorax, and is called from its direc-
tion  the Recurrent.

    The extreme  irritability  of the glottis is  unequivocally
      demonstrated  by  the  cough which is  excited  when a
      drop of water, or any other mild liquid, or a crumb of
      bread enters it. Notwithstanding this, a flexible  tube,
      or catheter, has several times been  passed into  the
      windpipe through the rima glottidis, and been endured
      by the patient a considerable time.
     The cough, which occurs  when these parts  are irritated,
      does not appear to arise exclusively from the irritation
      of  the membrane within the glottis;  for, if  it  were
      so,  mucilaginous  substances, when  swallowed  slowly,
      could  not suspend it.  Their  effect in relieving cough
      is universally  known;  and as they are  only applied to
      the surface exterior to the glottis, it is  evident  that the
      irritation of this surface must also produce coughing.
    Several  curious  experiments have been  made  to deter-
      mine  the effect of dividing the  different nerves which
      go to  the larynx; by which it appears that the recurrent
      branches supply parts  which are essentially necessary
      to the  formation  of the voice, whilst the  laryngeal
      branches supply parts which merely influence its modula-
      tion, or tone. See Mr.  Haighton's Essay on  this  subject:
      Memoirs of the Medical Society of London, Vol. III.

                  The Thyroid Gland
  May be described here, although a part  of it is situated
below the larynx.
  This body consists of two lobes, which are  united at
their lower extremities by a portion which extends across
the anterior part of the windpipe.  Each  lobe generally
rises upwards and backwards from  the second  cartilagi-
nous ring of the windpipe over the  cricoid cartilage and
a portion of the thyroid. It lies behind the sterno-hyoidei 
Of the Pharynx.                 37
and sterno-thyroidei muscles. It is of a reddish brown
colour, and appears to  consist of a granulous substance;
but its ultimate structure is not  understood. It is plenti-
fully supplied with blood,  and receives two  arteries on
each side: one from the laryngeal branch of the external
carotid:  and the  other from  the thyroid  branch of the
subclavian. .
   Notwithstanding this large supply of blood, there is no
proof that it performs any secretion; for although several
respectable anatomists have supposed that they discover-
ed excretory ducts passing to the windpipe,  larynx, or
tongue,  it is  now generally agreed that such  excretory
ducts are not to  be found. Several instances have  how-
ever occurred, in which air has been forced, by violent
straining, from the windpipe  into the substance of this
gland.
                    SECTION III.

                  Of the Pharynx.
  THE pharynx is a large muscular bag,  which forms
the great cavity behind the nose and mouth that termi-
nates in the oesophagus.
  It has been  compared to a funnel,  of which the oeso-
phagus is the pipe;  but  it differs from a funnel in  this
respect, that it is incomplete in front, at the part occu-
pied by the nose and mouth and larynx.
  It is connected above, to the cuneiform process of the
occipital bone, to the pterygoid processes of the sphenoi
dal, and to both the upper and lower  maxillary bones.  It
is in contact with the cervical vertebrae behind; and, op-
posite to the  cricoid  cartilage, it terminates in the  oeso-
phagus. 
38
Structure of the Pharynx.
    If the pharynx and oesophagus be  carefully dissected
 and  detached from  the vertebrae,  preserving the  con-
 nexion  of the pharynx with the head; and the head then
 be separated from the body, by dividing the articulation
 of the atlas and the os occipitis, and cutting through the
 soft parts below the larynx;  the resemblance to a funnel
 will be very obvious.
   In this situation,  if an  incision be  made from above
 downwards through  the whole extent of the posterior
 part of  the  pharynx, the  communication of  the nose,
 mouth, and windpipe, with this cavity, will be  seen from
 behind at one view.
   The openings into the nose,  or the posterior  nares, ap-
 pear uppermost.  Their figure  is irregularly oval or ob-
 long: they are separated from each  other by a thin parti-
 tion, the vomer.   Immediately behind, on  the external
 side of each of these orifices, is the Eustachian tube.
   The soft palate will appear extending from  the lower
 boundary of the posterior nares, obliquely backward and
 downwards, so as nearly to close the passage into the
 month. The uvula hangs from it; and, on each side of the
 uvula,  the edge of the palate is regularly concave.
   Below the palate, in the isthmus of the fauces, are the
 ridges or half-arches,  and the tonsils between them. The
 half-arch  which presents first,   in this view,  runs  ob-
 liquely downward and backward, and not parallel to the
 other.
   Close to the root of the  tongue is the epiglottis erect;
 and, immediately adjoining it, is an aperture large enough
 to admit  the end of a middle-sized finger. This aperture
is widest  at the extremity next to the epiglottis, and rather
narrower at the other  extremity: it is the glottis or open-
ing of the windpipe.  When the larynx is elevated, the
epiglottis can be readily depressed so as to cover it com-
pletely.
  The extremities of the arytenoid  cartilages, and their 
Structure of the Pharynx.            39
appendices, may be recognised at the posterior edge of
the glottis. At a short distance below this edge, the oeso-
phagus begins.
   The Pharynx is composed of the membrane continued
from the nose and  mouth internally, and of a stratum  of
muscular fibres  externally.  The internal membrane is
very soft and flexible,  and perforated  by many mucife-
rous ducts.  The surface which it forms is rather rough,
owing to the  mucous glands which it covers. It has a red
colour, but not so  deep as that of some other parts. It is
connected to the muscular stratum  by a loose  cellular
membrane.
   The muscular coat consists of three different portions,
which are considered as so many distinct muscles.
   The fibres of each of these  muscles  originate on each
side, and run in an oblique direction to meet in the mid-
dle, thus forming  the  posterior external surface of the
dissected pharynx.
   The fibres of the upper muscle originate from the cu-
neiform process  of the  occipital bone, from the pterygoid
processes of the os sphenoides, and from the upper and
lower jaws,  near the last  dentes molares, on each  side.
They unite in a middle line in the back of the pharynx.
   The fibres of the middle muscle originate principally
from the lateral parts of the os hyoides,  and from the lip-a-
ments which connect that bone to the  thyroid cartilage.
The superior fibres run  obliquely  upwards, so  as to
cover a part of the first mentioned muscle, and terminate
in the cuneiform process of the occipital bone; while the
other fibres unite with  those of the opposite side in the
middle line.
   The fibres of the lower muscles arise from the thyroid
and the cricoid cartilages, and terminate also in the mid-
dle line. Those  which are superior, running obliquely
upwards; the inferior, nearly in a transverse direction. 
40            Structure of the  Pharynx.
  It is obvious, from the origin and  insertion of these
fibres, that the pharynx must have the power of contract-
ing its dimensions in every respect; and, particularly, that
its diameter may be  lessened at any place;  and that the
whole may be drawn upwards. 
SYSTEM OF  ANATOMY.
PART VII.
                 OP THE THORAX.


BEFORE the thorax is described, it will be in order to
consider the
                    Mamma;
  Or those glandular bodies, situated on the anterior part
of it, which, in females, are destined to the secretion of
milk.
  These glands lie between the skin and the pectoral mus-
cles, and are attached to the surfaces of those muscles by
cellular membrane.
  They are of a circular form; and consist of a whitish
firm substance, divisible into small masses or lobes, which
are composed of smaller portions or lobuli. Between these
glandular portions a great deal of adipose matter is so dif-
fused, that it constitutes a considerable part of the bulk of
the mammae.
  The gland however,  varies greatly in thickness in the
same person at different periods of life.
  The mammas become much enlarged about the age of
puberty.  They are also very large during pregnancy and
  Vol. II.               F 
42
Mamma.
 lactation; but after the period of childbearing, they dimi-
 nish considerably.  Thty are supplied with blood by the
 external and internal  mammary arteries, the branches of
 which enter them irregularly in several different places.
   The veins correspond with the arteries.
   From the  small  glandular portions  that compose  the
 mamma, fine excretory tubes arise, which unite together
 and form the great lactiferous ducts of the gland.  These
 ducts  proceed  in a radiated manner from the circumfer-
 ence to the center,  and terminate on the surface of the
 nipple.
   They are commonly about fifteen in number, and vary
 considerably in size:  the largest of them being more than
 one sixth of an inch in diameter.
   They can be very readily injected by the orifices of the
 nipple, from a  pipe filled  with  mercury, in subjects who
 have died during lactation or pregnancy; but they are very
 small in subjects of a different description.
   It has  been  asserted, by respectable anatomists, that
 these ducts communicate freely with each other; but they
 do not appear to  do so: each duct seems to be connected
 with its proper branches only.
   Haller appears to have  entertained the remarkable sen-
 timent, that  some of the ducts originated  in the adipose
 matter about the gland, as well as in the glandular sub-
 stance.*
   The papilla,  or nipple, in which these ducts terminate,
 is in the center of the mamma: it consists of a firm elastic
^ubstance, and  is nearly cylindrical in form. It is rendered
 tumid by irritation, and by certain  emotions.
   The lactiferous ducts  terminate  upon  its extremity.
 When it is elongated, they can freely discharge their con-
 tents;  but when it contracts, this discharge is impeded.
   The skin immediately around the nipple is of a bright

        * Elementa Physiologiae Tom. 7, Pars 11. pag: 7. 
Mamma.
4,3
red colour in virgins of mature age.  In pregnant women
it  is sometimes almost black; and in women who have
borne children it is often brownish. It abounds with seba-
ceous glands, which form small eminences on its surface.
   This gland exists in males,  although it is very small.
In  boys, soon after birth,  it has often been known to
tumify and  become very painful, in consequence of the
secretion and accumulation of a  whitish fluid, which can
be discharged by pressure.  It also sometimes swells and
is painful, in males at the age of puberty.
   There have been some instances in which it has secre-
ted milk in adult males; and a few instances also in which
it has been affected with cancer, in the same sex.
   The mamma is plentifully supplied with absorbent ves-
sels, which pass from it to the  lymphatic glands in the
axilla.
   Its nerves are principally derived from the  great plexus
formed by the nerves of the arm. 
44
                    CHAPTER I.

        OF THE GENERAL CAVITY OF THE THORAX.

                    SECTION I.

       Of the form of the Cavity of the Thorax.

THE osseous  structure of the thorax is described  in
vol. I. page 83.  The cavity is completed by the intercostal
muscles, which close the vacuities between the ribs; and
by the diaphr gm, which fills up the whole space included
within its lower margin.
  If we except  the apertures of the diaphragm, which are
completely occupied by the aorta, the vena cava, and the
oesophagus, &c. the only outlet of this  cavity is above: it is
formed by the upper ribs, the first dorsal vertebra, and the
sternum. The figure of this aperture is between  that of
the circle and the oval; but it is made irregular by the ver-
tebra, and by the upper edge of the sternum.
   When the superior extremities  and the muscles appro-
priated to them  are removed, the  external figure of the
thorax is conical; but  the  cavity formed  by it is consi-
derably influenced by the spine, which protrudes into it;
while the ribs, as they proceed from the spine, curve back-
wards, and thus increase its prominency in the  cavity.
   The diaphr igm has a great effect upon the figure of the
cavity of the thorax.  It protrudes  into it from below, with
a convexity of such form that  it has been compared to an
inverted bowl;  so that, although it arises from the lower
margin of the thorax, the central parts of it are nearly as
high as the fourth rib. 
Pleura.
45
  The position of the diaphragm is also oblique. The an-
terior portion of its margin, being connected to the seventh
and eighth ribs, is much higher than the posterior portion,
which  is attached to the eleventh and twelfth.
  In consequence of the figure and position of the dia-
phragm, the form of the cavity of the thorax resembles
that of the hoof of the ox when its posterior part  is pre-
sented  forwards.
                     SECTION II.

          Of the arrangement of the Pleura.
   THE thorax contains the two lungs and heart, as well
as several very important parts of smaller size.
   The lungs occupy the greatest part of the cavity; and to
each of them is appropriated a complete sac, called Pleura,
which is so arranged that it covers the surface of the lungs,
and is continued from it to the contiguous surface of the
thorax, which it lines. After covering the lung, it is ex-
tended from it to the  spine posteriorly,  and the sternum
anteriorly:  so that in tracing the pleura in a circular  di-
rection, if you  begin  at the sternum, it proceeds on the
inside of the ribs to the spine;  at the spine it leaves the
surface of the thorax, and proceeds directly forwards
towards the sternum.  In its course from the spine to  the
sternum, it soon meets with the great branch of the wind-
pipe and  the bloodvessels, which go to the lung: it con-
tinues on these vessels and round the lung until it arrives
at the anterior side of the vessels, when it again proceeds
forwards until it arrives at the sternum.  Each  sac being
arranged in the same way, there is a part of each extended
from the spine to the  sternum.  These  two laminae forni
the great vertical septum of the thorax, called Mediasti-
num.  They are situated at some distance from each other; 
46
Mediastinum.
 and the  heart, with  its investing membrane or pericar.
 dium, is placed  between them.
   The pericardium is also a complete  sac or bladder,
 which, after covering perfectly the surface of the heart, is
 extended from it so as to form a sac, which lies loose about
 it,  and appears to contain it.  This loose portion adheres
 to  those parts of the  laminae of the mediastinum with
 which it is contiguous; and thus three chambers are form-
 ed within the cavity of the thorax: one for each lung, and
 one for the heart.
   The two  laminae of  the pleura, which constitute the
 mediastinum, are at different distances from each other, in
 different places.  At the upper  part of the thorax, they ap-
 proach each other from the internal edges of the first ribs;
 and, as these include a space which is nearly  circular, the
 vacuity between these laminae  is necessarily of that form,
 at its commencement above.
   Here therefore is a space between them above,  which
 is occupied  by the great transverse vein  that carries the
 blood of the left subclavian and the left internal jugular
 to the  superior cava;  by the trachea; by the oesophagus;
and by the subclavian and carotid arteries,  as  they rise
 from the curve of the aorta. This space  is bounded  below
 by the above mentioned curve of the aorta.
  The heart and pericardium are so placed that there is a
 small distance between them  and the sternum: in this
 space the two laminae of the mediastinum are  very near to
each other;  and  cellular substance  intervenes  between
them.  This portion of the mediastinum is called the An-
 terior Mediastinum.
  Posteriorly, the heart and pericardium are  also at a
small distance  from the spine; and here the laminae of the
mediastinum are at a greater  distance  from  each  other,
and form a long  narrow cavity which  extends down the
thorax in front of the vertebrae:  this is called the Poste-
rior Mediastinum. It contains a considerable portion  of 
              Preparation of the Thorax.            4?

the aorta as it descends from its curve, the oesophagus,
the thoracic  duct, and the vena azygos.  The aorta is in
contact with the left lamina, and can often be seen through
it when the left lung is lifted up.
   The oesophagus, is in contact with the  right lamina: in
its progress downwards, it inclines to the left side and is
advanced before the aorta.
   The vena azygos appears posterior to the oesophagus:
it proceeds upwards until it is as high as the right branch
of the windpipe: here it bends forward, round that branch,
and opens into the superior cava, before  that vein opens
into the right auricle.
   The thoracic  duct proceeds upwards from below, lying
in the spine between the" aorta and the vena azygos, until
the beginning of the curve of the aorta, when it inclines
to the left, proceeding towards the place of its termination.

     The formation of the mediastinum, and  the arrangement
       of the pleura, as well as  the  connexion of these mem-
     - branes with the parts contained in the thorax, may be
       studied advantageously,  after the subject has been pre-
       pared in the manner now to be described.
     Take away, from each side, the five ribs which are situated
       between the  first and last true ribs, by separating their
       cartilages  from the sternum, and their heads from the
       spine; so that the great cavities of the thorax may be laid
       open.
     The precise course of the mediastinum is thus rendered ob-
       vious; and the sternum may now be divided with a saw
       throughout its  whole  length in  the same direction; so
       that the division of the bone may correspond with the
       space between the laminae of the mediastinum.
     Separate the portions of the  sternum cautiously, so  as to
       avoid  lacerating the laminae of the mediastinum;  and
       keep them separate, while the trachea  is dissected from
       the neck into the cavity of the thorax; the great trans-
       verse  v£in and  the descending  cava are dissected to
       the pericardium; and the left carotid artery, with  the
       right subclavian and carotid, are dissected to  the curve 
48             Preparation of the Thorax.
  of the aorta, taking care not to destroy the laminae of the
  mediastinum.
After this preparation the upper space between the laminae
  of the mediastinum can be examined; and the relative
  situation of the trachea and the great vessels in it can be
  understood. The anterior mediastinum can also be  stu-
  died: the root of each lung, or its  connexion with the
  mediastinum,  may be seen perfectly; and the precise si-
  tuation of the lung, in its proper cavity, may bewell con-
  ceived.
After this,  while the portions of the sternum are separated,
  the pericardium may be opened,  and the heart brought
  into view: the attachment of the pericardium to the  me-
  diastinum, and to the  diaphragm, may be seen with ad-
  vantage in this situation. The portions  of the sternum
  may  now be detached  from the ribs, with which they re-
  main connected; and further dissection may be perform-
  ed to examine the posterior mediastinum and its contents,
  and the parts which constitute the roots of the lungs. 
49
                    CHAPTER II.

  OF THE HEART AND THE  PERICARDIUM, AND THE GREAT
         VESSELS CONNECTED WITH THE HEART.

                    SECTION II.

                 Of the Pericardium.

THE heart  is inclosed  by a  membranous sac, which,
upon  a  superficial view, seems only connected with  its
great vessels; but which, in fact, adheres closely to the
whole of its surface.  From this surface it is extended to
those  vessels; from which it proceeds, after the manner of
the reflected membranes, and forms an inclosure that lies
loosely about the heart. If it  were dissected  from the
heart, without  laceration or wounding, it would be an
entire sac.
  The pericardium, thus arranged, is placed between the
two laminae of  the mediastinum, and adheres firmly to
them  where  they are contiguous to it: it also adheres
firmly to the diaphragm  below, and thus preserves the
heart  in its proper position.
  The figure of the pericardium, when it is distended, is
somewhat conical; the base being on  the diaphragm. The
cavity formed by it is larger than the heart after death,
but it is probable that the heart nearly fills it during life;
for, when this organ is distended by injection, it often oc-
cupies the whole cavity of the pericardium.
  The pericardium is composed of two laminae, the inter-
nal  of which covers the heart, as has been already descri-
bed; while the external merely extends over the loose por-
tion of the other, and blends itself with the mediastinum,
where that membrane invents the great vessels.
  Vol. II.                G 
50
Of the Heart.
  The internal surface of the pericardium is very smooth
and polished; and in the living subject is constantly moist-
ened with a fluid, which  is probably effused from the ex-
halent vessels on its surface.
  The quantity of  this fluid does not  commonly exceed
two drams; but in cases of disease it sometimes amounts
to many ounces.* It is naturally transparent, but slightly
tinged with red in children, and yellow in old persons. It
is often slightly tinged with red in persons who have died
by violence.
                     SECTION II.

                     Of the Heart.
   THE great organ of the circulation consists of muscu-
lar fibres, which are so arranged that they give  it a coni-
cal form, and compose four distinct cavities within it.
   Two  of these cavities,  which are  called Auricles, re-
ceive the contents of the veins; the other two communi-
cate with the arteries, and are called Ventricles.
   The auricles form  the basis of the cone; the ventricles
the body and apex.
   The structure of  the  auricles is much  less  firm than
that  of the ventricles, and consists of a smaller proportion
of muscular fibres. They appear  like appendages  of the
heart, while the ventricles  compose the body of the vis-
cus.
   The  ventricles  arc very thick,  and are  composed of
muscular fibres closely compacted.
   The figure  of the heart  is not regularly conical;  for

  * The pericardium  has been  so distended, by effusion in dropsy
that it has formed a tumour, protruding on the neck from under the
sternum. This tumour had a strong pulsating motion. It disappear-
ed completely when the other hydropic symptoms were relieved. 
               Connexions of the Heart.             51-

a portion of it, extending from the apex to the base,  is
flattened; and in its natural position, this flat part of the
surface is downwards.
  It is placed obliquely in the body; so that its base pre-
sents backward and to the right,  and its apex forward
and to the  left.
  Notwithstanding this obliquity, the terms right and left
are applied to the different sides of the heart, and to the
different auricles  and  ventricles;  although  they might,
with equal propriety, be called anterior and posterior.
  The two great veins, called  Vena Cava, which  bring
the  blood  from every part of the  body,  open into the
right auricle  from above  and below; the right auricle
opens into the right ventricle; and from this ventricle
arises the  artery denominated  Pulmonary, which passes
to  the lungs.
   The Pulmonary  veins,  which  bring back  the  blood
 from  the  lungs,  open into the left  auricle: this auricle
 opens into the left ventricle; and from this ventricle pro-
 ceeds the  Aorta,  or great artery, which carries blood to
 every part of the  body.
   The heart is preserved in its position, 1st, by the venae
 cavse, which are connected to  all the parts to which they
 are contiguous in their course; 2d, by the vessels  which
 pass between it and the  lungs, which  are retained in a
 particular  position by  the mediastinum; 3d, by the aorta,
 which is attached to the mediastinum in its course down-
 wards, «fter making its great curve; and 4th, by the pe-
 ricardium, which is attached to the great vessels and to
 the mediastinum. By these different modes the basis of
 the heart  is fixed, while its  body and apex are perfectly
 free from  attachment,  and only contiguous to the peri-
 cardium.
    The external surface of the heart, being formed by the
 pericardium, is very smooth:  under this  surface a large
 quantity of fat is often found. 
 52                Right Auricle'.

    The two auricles are contiguous to each  other at the
 base, and are separated by a partition which is common
 to both.
    The Right Auricle originates from  the junction of the
 two vena? cavae. These veins are united at some distance
 behind the right ventricle,* and are dilated anteriorly into
 a  sac or pouch, which is called the Sinus, and extends to
 the right ventricle, to which it is united.
   The upper part of this pouch, or sinus, forms a point
 with indented edges, which  is detached from the ventri-
 cle, and lies loose  on  the  right side  of  the  aorta.  This
 point  has some resemblance  to the  ear of a dog, from
 from which circumstance the whole cavity has been called
 auricle; but by many persons the cavity is considered ab
 consisting of two portions: the Auricle, strictly speaking;
 and the Sinus Venosus, above described:  they however
 form but one cavity.
   This portion of the heart, or Right Auricle, is of an
 irregular  oblong figure. In  its  posterior  surface, it is
 indented; for the  direction  of the  two  cavse,  at  their
junction,  is not precisely the  same;  but  they form  an
 angle, which causes  this indentation.  The anterior por-
 tion of the auricle, or that which appears like a pouch be-
 tween the ventricle and the veins, is different  in its struc-
 ture from the posterior part,  which is strictly a portion of
 the veins.  It consists  simply of muscular fibres which
 are arranged in fasciculi that cover the whole internal sur-
 face: this is also the case with the point, or that part which
 is  strictly called auricle.
   These  fasciculi  are denominated Musculi Pectinati,
 from their resemblance to the teeth of a comb.
   That part  of  the internal surface, which is formed by

  * In this description the heart is supposed to be in its natural po-'
 sition. 
                   Right Ventricle.                 53

the septum, is smooth; and  the whole is covered  by a
delicate membrane.
  On the surface of the septum, below the middle, is an
oval depression, which has a thick edge or margin: this
is called the Fossa  Ovalis. In the foetal heart, it was the
Foramen Ovale, or  aperture which forms the communi-
cation between the two auricles.
   Near this fossa is  a large semilunar  plait,  or valve,
with its points and concave edge uppermost, and convex
edge  downwards. It was described by Eustachius,  and,
therefore, is called the Valve of Eustachius.
   Anterior to  this valve, and near the union of  the auri-
cle and  ventricle, is the orifice of the proper vein of the
heart, or the  coronary vein. This  orifice is covered by
another semilunar valve, which  is sometimes reticulated.
   The aperture, which forms the communication between
the right auricle and right ventricle, is about an inch in
diameter. From its whole  margin arises a valvular ring,
or  duplicature of the membrane lining the surface: this
circular valve is divided into  three angular  portions,
which are  called Valvula Tricuspides. From their mar-
gins proceed a great number of fine tendinous threads,
which are connected to a number of distinct portions of
muscular substance, which arise from the ventricle.
   The  right Ventricle, when examined separate from the
other parts of the heart, is rather triangular in its figure.
It is composed entirely of muscular fibres  closely com-
pacted; and is much  thicker than the auricle,  although
not so thick as the  other ventricle. Its internal surface  is
composed of bundles  or columns of fleshy fibres, which
are of various thickness and length.  Some of  these co-
lumns  arise from the  ventricle, and  are  connected with
the tendinous  threads, which are attached to the margin
of the tricuspid valves: the direction of them is from the
apex of the heart towards the base. Others of the columns
arise from  one part of the surface of the ventricle, and  • 
54                 Right Ventricle.
are inserted into another part. A third species are attach-
ed to the ventricle  throughout their whole length, form-
ing ridges or eminences on it. The columns  of the two
last described species are very numerous. They present
an elegant reticulated surface when the ventricle is laid
open, and appear also to  occupy a considerable portion
of the cavity of the heart, which some of them run across
in every  direction  near  the apex.  They  are all  covered
by a membrane continued from the auricle  and the tri-
cuspid valves; but this membrane appears more  delicate
and transparent in the ventricle than it is in the auricle.
  A portion of the internal surface of the ventricle, which
is to the left, is much smoother and less fasciculated than
the rest:  it leads to the  orifice of the pulmonary artery,
which arises from it near the basis of the  ventricle. This
artery is very conspicuous, externally, at the  basis of the
heart.
  It is very evident, upon the first inspection of the heart,
that the valvular tricuspides will permit the blood to flow
from the auricle to the ventricle; but must rise and close
the orifice, and thereby prevent its passage  back again,
when the  ventricle contracts.
  The use of the tendinous threads, which  connect the
valves  to the  fleshy columns, is  also very evident:  the
valve is supported by this  connexion, and  prevented from
yielding to the pressure and opening a passage into  the
auricle. The blood, therefore,  upon the contraction of
the ventricle,  is necessarily  forced  into  the  pulmonary
artery; the passage to which is now perfectly free.  Into
this artery the membrane  lining the ventricle seems con-
tinued;  but immediately within the  orifice of the artery
it is formed into three semicircular folds, each of which
adheres to the surface of the artery by its circumference,
while the edge constituting its  diameter  is loose. In the
middle of this loose edge, is a small firm  tubercle, called 
                    Left Auricle.                   55

Corpusculum Arantii* which adds to the strength of the
valve.  Each of these valves, by its  connexion with the
arterv, forms a sac or pocket, the orifice of  which opens
forward towards the course of the artery, and the bottom
of it presents towards the ventricle. Blood will, therefore,
pass from the ventricle in the artery, and along it, with-
out filling these sacs;  and on the contrary, in this course,
will compress them and keep them  empty. If it  moves
in the artery  towards the heart, it will  necessarily fill
these sacs,  and press the semicircular portions from the
sides of the artery against  each other: by this  means a
partition, or septum,  consisting of three portions, will be
formed between  the  artery and the  heart, which will al-
ways exist  when the artery compresses (or acts upon)
its contents. It  is demonstrable, by injecting  wax  into
the artery, in  a retrograde direction, that these valves do
not form aflat septum, but one which is convex towards
the heart, and concave towards the artery;  and that this
convexity  is  composed of three distinct parts, each of
which is convex. At the place where these valves are
fixed, the artery bulges out when  distended by a retro-
grade injection. The  enlargements thus produced are
called the  Sinuses of Valsalva, after the anatomist who
 first described them. The valves are called Semilunar;
 and, although they are formed by a very thin membrane,
 they are very strong.
   The Left  Auricle is situated on the left side of the
 basis of the heart. It originates from the junction of the
 four pulmonary veins; two of which come from  each
 side of the  thorax, and appear to form a large part of it.
 It is nearly of a cubic form; but has also an angular por-
 tion, which constitutes the proper auricle,  that proceeds
 from the upper and  left  part of the cavity, and is situ-
 ated on the left side of the pulmonary artery.

   • After Arantius, a professor at Bologna, who first described it. 
56
Left Ventricle.
   This  auricle is lined  by a  strong membrane,  from
 which the valves between it and the ventrirL <>ri^tnate:
 but it has no fleshy columns or musculi pectinati, except
 in the angular process properly called auricle.
   These valves, and the  orifice communicating with the
 ventricle, resemble  those which  have been  already de-
 scribed between the right auricle and ventricle; but with
 this difference,  that  the valvular ring is divided into  two
 portions only, instead of  three, which are called Valvula
 Mitrales. The tendinous threads, which are connected to
 the muscular columns, are also  attached to these  valves,
 as in  the case of the right auricle.
   These valves admit the passage of blood from the au-
 ricle into the ventricle, but completely prevent its return
 when the ventricle contracts. One of them is so situated
 that it covers the mouth  of the aorta while  the blood is
 flowing into  the ventricle, and  leaves that orifice open
 when the ventricle contracts, and the  passage to the au-
 ricle is closed.
   The Left Ventricle is situated posteriorly,  and to  the
 left of the Right Ventricle: its figure is different, for it is
 rather conical, and it is also longer.
  The internal surface of this ventricle resembles  that of
 the right ventricle; but the columnae carneae are stronger
 and larger.
  On the right side  of this ventricle is the mouth of the
 aorta. The surface of the ventricle  near this opening is
 smooth.
  The cavity of this ventricle is supposed to be smaller
 than that of the right: but the amount of the difference has
 not been accurately ascertained.
  This ventricle must have  much more force than  the
 right, as its parietes are so  much thicker. Their thickness
 often exceeds half an inch.
  The difference  in the strength of  the two ventricles
 probably corresponds with the difference between the  ex-
tent of the pulmonary artery and the aorta. 
Muscular Fibres of the Heart.
57
  The thickness of the  septum  between  the  ventricles
is thicker than the sides or parietes of the right ventricle,
and less thick than those of the left.
  The muscular fibres  of the heart are generally less
florid than those of  the voluntary muscles: they are also
more closely compacted together.  The direction of many
of them is oblique or spiral; but this general arrangement
is very intricate: it is such, however, that the cavities  of
the heart are lessened, and probably completely obliterat-
ed, by the contraction of these fibres.*
  The external surface of the  heart is covered by that
portion of the pericardium which adheres to it. Adipose
matter is often deposited between this membrane and the
muscular surface; being distributed irregularly in various
places.
  This membrane is continued from the  surface  of the
ventricles over that of the auricles. When it is dissected
off from the place of their junction, these surfaces appear
very distinct from  each other.
  The proper bloodvessels of the heart appear to  be ar-
ranged in conformity to the general laws  of the circula-
tion, and are very conspicuous on the surface.  There are
two arteries which arise from the aorta immediately after
it leaves the heart, so that their orifices are covered by two
of the semilunar valves.  One of  these passes from the
aorta between the pulmonary artery and the right auricle,
and continues in a circular course in the groove between
the right auricle and the right ventricle, and sends off its
principal branches to the right side of the heart.
  The other  artery of the  heart passes between the pul-
monary artery and the  left auricle. It divides into two
branches: one, which is anterior, passes to a groove  on
the surface, corresponding to the septum between the two

  * Mr. Home has given a precise description of the muscular fibres
of the heart in his Croonian Lecture.  London Philosophical Transac-
tions for 1795,part l.page 215.
  Vol. II.               H 
>8               Coronary Vessels, &c.

 ventricles, and continues on it to the  apex of  the heart,
 sending off branches in its course; another, which is pos-
 terior and circumflex,  passes between the left auricle and
 ventricle.
   The great vein of the heart opens  into  the under side of
 the right auricle, as has been already mentioned: the main
 trunk of this vein passes for some distance between the
 lett auricle and ventricle.*
   From  the course of these different  vessels round the
 basis of the ventricles of the  heart, they are  generally
 called  Coronary Vessels:  the arteries  are denominated,
 from their position, Right and Left Coronary.
   The nerves of the heart come from the cardiac plexus,
 which is composed of threads derived from the intercostal
 or great  sympathetic nerves, and the nerves of the eighth
 pair.

   * It was asserted by Vieussens at an early period, in the last centu-
 ry, and soon afterwards by Tliebesius, a German Professor, that there
 were  a number of small orifices in the texture of the heart, which
 opened into the different cavities on both sides of it.
   This assertion of a fact so difficult to reconcile with the general
 principles of the circulation, was received with great hesitation: and
 although it was confirmed by some very respectable anatomists of the
 last century, it was denied by others. Some of the anatomists of the
 present day have denied the existence of these orifices, and  some
 others have neglected them entirely.
   The subject has lately been.brought forward in the  London Philo-
 sophical Transactions for  1798, Part I, by a very respectable anato-
 mist, Mr. Abernethy, who states that he has  often passed a coarse
 \v;.xcn injection from the proper arteries and  veins of the heart into
 all the cavities of that organ, and particularly  into the Left Ventricle.
 Bui it was only in subjects with diseased lungs that this was/iraclica'
 ble.
   The existence of this communication between the coronary vessels
 and the great cavities of the heart seems therefore to be proved. The
 easy demonstration in such subjects is ingeniously referred by  Mr.
 Abernethy. to the obstruction of the circulation in the lungs: and he
 regards the communication as a provision enabling the coronary ves-
 sels to unload themselves, when the coronary vein Cannot discharge
 freely into the right auricle. 
The Great Vessels.
59
                    SECTION IIL

Of the Aorta,  the Pulmonary Artery and Veins, and the
          Vena Cava; at their commencement.
   THE  two great arteries, which arise from  the heart,
commence abruptly,  and appear to be extremely different
in their composition and structure from the heart.
   They are composed of a substance, which has a whitish
colour and very dense texture, and is very elastic as well as
firm and strong.
   When the pericardium is removed, these arteries ap-
pear to proceed together from  the upper part of the basis
of the heart: the pulmonary artery being placed to the left
of the aorta with the  left auricle on the left side of it, and
the right auricle on the right side of the aorta. The pul-
monary artery arises from the most anterior, and left part
of the basis of the right ventricle, and proceeds obliquely
backwards and upwards; inclining gradually to  the  left
side for about  eighteen or twenty lines;  when  it divides
into  two  branches which pass to the two lungs.
   The aorta arises from the left  ventricle, under the origin
of the pulmonary artery, and immediately proceeds to the
right, covered by that vessel, until it mounts up between
it  and the right auricle: it then forms a great  curve, or
arch, which turns backward and to the left, to a considera-
ble distance beyond the pulmonary artery. In this course,
it crosses the right branch of the pulmonary artery;  and,
turning down in the angle between it and the left* branch,
takes a position on the left side of the spine.
   The course  of this  artery, from its  commencement at
the ventricle, to the end of the  great curve or arch, is ex-
tremely varied.
   The uppermost part of the  curve is in  the bottom of
the chamber formed  by the separation of the laminae of
the mediastinum when they join the first rib on each side. 
60   Pulmonary Artery and Veins and Vena Cava.

  From this  part of the curve three  large branches go
off, viz: one,  which soon divides  into the carotid and the
subclavian arteries of the right side; a second, somewhat
smaller, which is the left carotid; and a third, which is the
left subclavian artery.
  When the  heart and its great vessels are viewed from
behind, (after they have all been filled with injection; and
the pericardium,  mediastinum, and windpipe have been
removed,) the aorta appears first,  descending behind the
other vessels; the pulmonary artery then appears, dividing
so as to form an obtuse angle with its two great branches,
each of which divides  again before it enters the lung to
which  it is destined.
  Under the  main trunk of the pulmonary artery is the
left auricle: its posterior surface is  nearly of a square form,
and each of the pulmonary veins proceeds from one of its
angles. These veins ramify in the substance of the lungs,
at a very short distance from the  auricle: the two upper-
most of them are situated rather anterior to the branches
of the  pulmonary artery.
   In this posterior view, the  pulmonary vessels of the
right side cover a great part of  the right  auricle,  as it is
anterior to them. The lower portion of the auricle, with
the termination of the inferior  cava, is to be seen below
them.  Above them,  the superior cava  appears; and in
that part of  it,  which is immediately above the right
branch of the pulmonary artery, is the orifice of the vena
azjgos.
   In its natural situation in the thorax, the superior cava
is connected by cellular membrane to the right lamina of
the mediastinum, and supported by it. At a small distance
below the upper edge of the sternum, it receives the trunk
formed by the  left subclavian  and internal jugular vein
which passes obliquely across the sternum below its inner
edge,  in the upper space  between  the laminae of the medi-
astinum. 
61
                   CHAPTER III.

           OF THE TRACHEA AND THE LUNGS.

ALTHOUGH the principal part  of the windpipe  is
situated in the neck above the cavity of the thorax, it is
so intimately connected with the lungs, that it is necessary
to describe them together.


                     SECTION I.

                   Of the Trachea.
  Trachea is the technical name for the windpipe,  or
tube which passes from the larynx to the lungs.
  This tube begins at the lower edge of the cricoid car-
tilage, and passes down the neck in  front of the cesopha*
gus as low as the third dorsal vertebra,  when it divides
into two branches called Bronchia, one of which goes to
the right and the other to the left  lung and ramifies very
minutely in them.
  There is in its structure a number of flat cartilaginous
rings placed at small distances from  each other, the edges
of which are connected by membrane  so that they  com-
pose a tube.
  These cartilaginous rings are not complete, for they do
not form more than three fourths or four fifths of a circle;
but their ends are connected by a membrane which forms
the posterior part of the tube.
   They are not alike  in their size or form; some of them
are rendered broader than others,  by the union of two or
three rings with each other, as the uppermost. The lower-
most also is broad,  and has a form which is accommodated 
62
Structure of the Trachea.
to the bifurcation  of the tube. Their number varies, in
different persons, from fifteen to twenty.
   These rings may be considered as forming a part of the
first proper coat of the trachea; which is composed of
them, and of an elastic membrane  that occupies all the
interstice between them; so that the  cartilages may be re-
garded as fixed in this membrane.
   A  similar arrangement of  rings exists in the great
branches of the bronchiae;  but  after  they ramify in the
lungs, the cartilages are no longer in the  form of rings:
they are irregular in their figures, and are  so arranged in
the membrane that they keep the tube completely open.
These portions of cartilage do not  continue throughout
the Whole extent of  the ramifications;  for they  become
smaller, and finally disappear, while the membranous tube
continues without them, ramifying minutely, and proba-
bly forming the air cells of the  lungs.
   This membrane is very elastic:  the lungs are very elastic
also; and it is probable that their elasticity is derived from
this membrane.
   On the inside of this coat  of the trachea is an arrange-
ment of muscular fibres, which may be called a muscular
coat. It is best seen by peeling off or removing the inter-
nal coat to be next described.
   On the membranous part of the trachea,  where the car-
tilaginous  rings are  deficient,  these muscular fibres run
evidently in a transverse direction: in the spaces between
the cartilages their direction is  longitudinal.  There is
some reason to doubt whether these longitudinal fibres are
confined altogether to the spaces between the cartilaginous
rings, and attached only to their edges, because there  is a
fleshy substance on the internal surface of the rings, which
appears to be continued from  the spaces  between them.
   The internal  coat of  the trachea is a thin and delicate
membrane, perforated with an immense number  of small
foramina, which arc the orifices of mucous ducts. 
Black Glands of the Bronchia.          63
  On the surface of this membrane there is an appearance
of longitudinal fibres which are not distributed uniformly
over it, but run in fasciculi in some places, and appear to
be deficient in others. These fasciculi are  particularly
conspicuous in the  ramifications of the bronchiae in the
lungs.
  On the posterior membranous portion  of the trachea,
where the cartilages are deficient, a considerable number
of small glandular bodies  are placed, which are supposed
to communicate with the  mucous ducts that open on the
internal  surface. If these bodies  are  removed from the
external surface of this portion, and the muscular fibres
are also removed from the internal, a very  thin membrane
only  remains,  which is very different from that which is
left between the rings,  when the fleshy substance is re-
moved from that situation.
  The reason  of the deficiency in the rings, at this poste-
rior part, is not very obvious. It continues  in the bronchiae
until the form of their cartilages is changed in the lungs:
if it were only  to accommodate the oesophagus, during ihe
passage of food, there would be no occasion for its exten-
sion  to the bronchiae.
  At the bifurcation of the trachea, and on the bronchiae,
are  a number of black coloured bodies, which  resemble
the lymphatic glands in form and texture.  They continue
on the ramifications of the bronchiae some distance into
the substance of the lungs. Their number is often very
considerable; and they vary in size from three or four
lines  in  diameter to  eighteen or twenty.  As lymphatic
vessels have been traced  to and from  them during their
course to the thoracic duct, they are considered as lym-
phatic glands. 
64
Root of the Lungs.
                     SECTION II.

                     Of the Lungs.
   THERE are two of these organs: each of which occu-
 pies one of the great cavities of the thorax
   When placed together,  in their natural position, they
 resemble the hoof of the ox, with its back part forward;
 but they are at such a distance from each other, and of
 such a figure, that they allow the mediastinum and heart
 to intervene; and they cover every part of the heart ante-
 riorly, except a small portion at the apex.
   Each  lung fills completely the cavity in which it is
 placed, and every part  of  its external  surface is in con-
 tact with some part of the  internal surface of the cavity;
 but when in a natural and healthy stare, it is not con-
 nected with any part except the laminae of the medias-
 tinum. One great branch of the trachea and of the pul-
 monary artery pass from the mediastinum to each lung,
 and enter it at a  place which  is rather nearer to the
 upper rib than to the diaphragm, and much  nearer to
 the spine than the sternum: at this place also the pulmo-
 nary veins return from the  lung to the heart.
  These vessels are inclosed in a membrane, which is
 continued over them from the mediastinum, and  ex-
 tended from them to the lung. Thus covered, they con-
 stitute what has been called the Root of the Lung.
  When their covering, derived from the mediastinum,
 is removed, the situation of these vessels appears to be
 such that the bronchiae are  posterior, the  branches of the
 pulmonary artery are  rather above and before, and the
 veins below and before them.
  Each of these vessels ramifies before it enters into the
substance of the lungs: the  bronchiae  and the branches of
the  pulmonary artery send each a large branch downward 
                 Colour of the Lungs.               65

to the  inferior part of the lungs, from which  the lower
pulmonary veins pass in a direction nearly horizontal. In
general, each of the smaller ramifications of the bronchiae
in the lungs is attended by an artery and a vein.
  Each lung is divided, by very deep fissures, into por-
tions which are called Lobes. The right lung is composed
of three of these lobes, and the left lung of two.
   The lungs are covered, as has been  already stated,
with the reflected portion  of the pleura continued from
the mediastinum,  which  is very  delicate,  and almost
transparent. They have,  therefore, a  very smooth sur-
face, which is kept  moist by exudation from the arteries
of the membrane.
   The Colour of the Lungs is different in different sub-
jects. In children they are  of a light red colour; in adults
they are often o£a light grey; owing to the deposition of
a black pigment in the substance  immediately under the
membranes which  form  their external surface.  Their
colour is often formed by a mixture of red and black. In
this case they are more loaded with blood, and the ves-
sels of the internal membranes being distended with it,
the red colour is derived  from them.
   The black pigment sometimes  appears in round spots
of three  or four lines in  diameter: under the external
membrane it is often in much  smaller  portions,  and
sometimes is arranged in  lines  in the interstices  of the
lobuli,  to  be hereafter mentioned. It is also diffused in
small quantities throughout the substance of the lungs.
   The source of this substance, and the use of it, are
unknown.
   The lungs are of a soft spongy texture;  and, in ani-
mals that  have breathed,  they have always a considera-
ble quantity of air in them.
  They consist of  cells,  which  communicate with the
branches  of the  trachea that ramify  through them in
every part.  These  cells  are  extremely small, and the
  Vol. II.                I 
 66            Structure of the Lungs.

 membranes which compose them are so thin  and deli-
 cate that if they are all filled  by an injection of wax,
 thrown  into the trachea, the whole cellular part  of the
 lung will appear like a mass of wax. If a corroded pre-
 paration be made of a lung injected in this manner with
 force, the wax will appear like a concretion.
   These effects of injection prove that the membranes
 of which the  cells  are  formed are  very thin; and,  of
 course,  that their volume is very small when  compared
 with the capacity of the cells.
   In those corroded preparations, in which the ramifica-
 tions of the bronchiae are detached from the wax  of the
 cells, these ramifications become extremely small indeed.
   If the lungs  of the human subject, or of animals  of
 similar construction, be examined when they are inflated,
 their cellular structure will be very obvious,  although,
 their cells are so small that they  cannot commonly be
distinguished by the naked eye. Each  of the extreme ra-
 mifications of the  bronchiae appears to be surrounded by
 a portion of this cellular substance, which is  gradually
 distended when air is blown into the ramification.
   This  cellular substance is formed into small portions
 of various angular figures, which are denominated Lo-
 buli: these  can be  separated to  a considerable  extent
 from each other.  They are covered by the proper coat
 of the lungs,  which is  extremely delicate, and  closely
 connected to  the  general covering  derived  from  the
 pleura.  Between  the lobuli, when they are in contact
 with each other,  there is a portion of common cellular
 substance,  which  is easily distinguished through the
 membrane  covering  the  lungs.  This  is  very  distinct
 from  the cellular  structure which communicates with
 the ramifications of the bronchia?, and contains air; for it
 has no  communication with the  air,  unless  the  proper
 coat of the  lungs be ruptured. If a pipe be introduced
 by a puncture of the external coat of  the lungs, and this 
The Tlwrax of the Foetus.
67
. interstitial  cellular  membrane be  inflated, it  will com-
 press the lobuli. This cellular membrane is always free
 from adipose  matter: it may be easily examined in the
 lungs of the bullock.
   Upon the membranes which compose the air cells, the
 pulmonary artery and vein ramify most minutely; and it
 seems to have been proved within the last thirty years,
 by the united labours of chemists and physiologists, that
 the great object of respiration is to effect a chemical pro.
 cess  between the atmospheric air, when taken into the
 air cells, and the blood which circulates in these  vessels.
   In addition to the bloodvessels which thus pass through
 the substance  of the lungs, there are several smaller ar-
 teries, denominated Bronchial, which arise  either from
 the upper intercostal, or from the aorta  itself:  they pass
 upon the bronchiae,  and are distributed to the  substance
 of the lungs. The veins which correspond with these ar-
 teries terminate ultimately in the vena azygos.
   The nerves  of the lungs are small in proportion to the
 bulk of  these organs. They are derived principally from
 the par vagum and  the intercostal nerves.
   The elasticity of the air cells of the lungs and of the
 ramifications of the; {bronchiae which lead to them, ap-
 pears by their rapid  contraction after distention,  and by
 the force with which they expel the air which is used to
 inflate them when taken out of the thorax.

               The Thorax of the Foetus.
   In  the  cavity between the laminae of the mediastinum,
 where they approach each other from the first ribs, is situ-
 ated a substance which is denominated the

                    Thymus Gland.
   This substance gradually diminishes after birth,  so that
in the adult  it is often not to be found: and when it exists
it is changed in its texture, being much firmer, as well as
greatly diminished. 
68            The  Thorax of the Foetus.
  In the foetus it is of a pale red colour; and during in- r
fancy it has a yellowish tinge. It generally  extends from
the thyroid gland, or a little below it, to the pericardium.
From its  superior portion two lateral processes are ex-
tended upwards: below, it is formed into two lobes, which
lie on the pericardium.
  If an incision be made into its  substance, a fluid can be
pressed out, which has  a  whitish colour, and coagulates
upon the  addition of alcohol.
  Although it is called a gland, no excretory duct has
ever been found  connected with  it.
  The bloodvessels of this body are derived from  the
tlivroid branches of the  subclavians, from the   internal
mammaries, and the vessels of the pericardium and medi-
astinum.

                   The Heart,
   And the great  arteries which proceed  from  it, have
some very interesting peculiarities in the foetus.
   In the septum between the two auricles, is a foramen
of sufficient size to  permit the  passage of a large quill,
which inclines to the oval form, with its longest diameter
vertical when  the body is erect. Oi*.the left side of  the
septum, a valve, formed by the lining membranes, is con-
nected to this foramen; and allows a free passage  to a fluid
moving from the right auricle to the left, but prevents the
passage of a fluid from the left to the right. This structure
is evidently calculated to  allow some of the blood which
flows into the right auricle  from  the two  venae  cavae to
pass into the left auricle of the heart,  instead of going in-
to the right ventricle.  As the contents of the left auricle
pass into the left ventricle, and from thence into the aorta,
it is obvious that the blood, which passes  from  the right
auricle into the left through this foramen, must  be trans-
mitted from the system of the vena cava to the system of
the aorta without going through the lungs, as it  must ne- 
              The Thorax of the Foetus.            69

cessarily do in subjects who do not enjoy the foetal struc-
ture.

       '  The Pulmonary Artery and the Aorta
  Have a communication in the foetus, which is very ana-
logous to the communication between the auricles of the
heart.
  From  the pulmonary artery, where it  divides into the
two great branches, another large branch continues, in the
direction of the main trunk, until it joins the aorta; with
which it communicates at a small distance below the ori-
gin of the left subclavian artery. In the young subject that
has never respired, it appears as if the pulmonary artery
was continued into the aorta, and sent off in its course, a
branch on each side, much smaller than itself, to each lung.
In subjects that have lived a few days, these branches to
the lungs are much larger; and then the main pulmonary
artery appears to have divided into three branches: one to
each lung, and one to the aorta; but that which continues
to the aorta is larger than either of the others.
   In the course of time, however, this branch of the aorta
is contracted, so that no fluid passes through it;  and it has
the appearance of a ligament, in which state it remains.
   The course of  the blood from the  right  ventricle,
through the pulmonary artery, to the aorta below its curve,
is more direct than that from the left ventricle to the same
spot, through the aorta at its commencement. The column
of blood in the aorta below its curve  is evidently propel-
led by the force of both ventricles: and this circumstance,
although it seems  to proceed merely from the state of the
foetal lungs, is particularly calculated for the very exten-
sive circulation which the foetus carries  on, by means of
the umbilical  arteries and vein in the  placenta. 
70
General Observations.
                 The Lungs of the Foetus
   Differ  greatly from those  of the adult. They appear
 solid, as if they were composed of the  parenchymatous
 substance which constitutes the matter of glands, rather
 than the light spongy substance of the lungs of adults.
 They differ also in colour from the lungs of older subjects,
 being of a dull red.
   They have greater specific gravity than  water; but if
 air be once inspired, so much of it remains in them that
 they ever afterwards float in that fluid.

     The nature of the process  of respiration,  and its effects
       upon the animal economy,  particularly upon the action
       of the  heart,  appear to be much  better understood at
       this time than  they were before the  discovery of the
       composition of the atmosphere, by  Dr. Priestley and
       by Mr. Scheele. The  publications  upon this  subject,
       which  have appeared since that period, viz. 1774, are
       therefore much more interesting to the student of me-
       dicine  than those which preceded them. Two of these
       publications ought  to be  particularly  noticed by him:
       viz. an essay, by Dr. Edward Goodwyn, intitled " The
       Connexion of life with respiration;" and—the " Phy-
       siological Researches of M. Bichat upon Life and Death.
       Part Second."*
     Th» general doctrines  respecting the oxygenation or de-
       carbonation of  the blood,  and the  absolute necessity
       that it  should  take place to a  certain  degree  in order

  * The student will derive much information  respecting  the pub-
lications on this subject, prior to 1804, from Dr. Bostock's Essay  on
Respiration.—Since the publication of that essay several interesting
papers on respiration have appeared, viz: Two memoirs by the late
Abbe Spalanzani;—" An Inquiry into the Changes induced on At-
mospheric Air by the Germination of Seeds, &c." by Ellis;__two very
important communications by Messrs. Allen and Pepys in the Trans-
actions of the  Royal Society of London for  1808 and  1809;—and
" Further Inquiries into the changes induced on Atmospheric Air."
Also  by Ellis. 
Cases of Malformation.
71
      to Jn-eserve life,  are confirmed  by a  number of cases
      of malformation of the heart or the great vessels, in
      which  the  structure was such that a considerable por-
      tion of venous blood passed from the right side of the
      heart to the aorta, without  going through the lungs.
      In  these different cases, notwithstanding the structure
      was somewhat varied,  the  symptoms produced were
      very much alike; differing in the respective patients in
      degree only, and not in kind.
        The symptoms indicating this structure are blue colour
      of the face, (such as generally accompanies suffocation)
      extending  more or  less over the whole  body, and par-
      ticularly apparent under the nails of the  fingers  and
      toes; anxiety about the region of the  heart; palpitation;
      laborious  respiration; sensations of great debility, &c:
      all  of which are greatly aggravated  by muscular exer-
      tion. These  effects have generally appeared to be pro-
      portioned to the quantity of venous blood admitted into
      the aortic system.*
         When  these appearances  take place  immediately
      after birth, it is probable that they depend entirely upon
      malformation of the heart or great  vessels; but when
      they commence at a subsequent period,  they are com-
      monly the effect of  a diseased  alteration  in the  lungs.
      They sometimes occur near the termination of fatal
      cases of pneumonia or catarrh;  but  a  different  cause,
      which has  not  latterly been suspected,  appears to have
      produced them in the following case related by  Dr.
      Marcet, in the  first volume of the Edinburgh Medical
      and Physical Journal.
         The  blue colour occurred  in a young woman twenty-
      one years of age, in whom  it had  never  been observed

  ' Cases of this  kind are related in several of the periodical  pub*
lications on medical subjects. Two of  them were described by the
late Dr. William Hunter in the  sixth volume of Medical Observa-
tions and  Inquiries,  by a Society of  Physicians in London; one
(quoted  by Dr. Goodwyn) is in the Observationes Anatoniicae of
Sandifort; and another, by Dr. J.  S. Dorsey, has lately been publish-
ed in the first number of the New England Journal of Medioine and
Surgery. 
    Adhesion of the Lungs to the Thorax.

 before. It came on during an affection of the breast, and
 was attended with great prostration of strength and dif-
.ficulty of breathing; as well as  cough, axle ma  of the
 hands and feet, and  several other symptoms.   About
 seven weeks after the commencement of these symp-
 toms  she died; when it was ascertained by dissection,
 that  there  was  no unnatural communication  whatever
 between  the  cavities of the heart,  and that  its valves
 were  all in a perfect and natural state.  The lungs were
 free from tubercles, or any other  appearance of disease*
 Their substance seemed more compact than  usual, espe-
 cially the left lung,  although it did  not sink  in  water;
 but they adhered every where to the inner surface of the
 thorax, to the diaphragm, and to the pleura covering the
pericardium.—This case is the more  remarkable, be-
 cause numberless instances  have  occurred  in  which
 very  large portions of the external surface of the lungs
 have  been found upon dissection to adhere to  the inter-
 nal surface  of the thorax without the occurrence of
 such symptoms during life.
may be inferred, from a statement published by M. Du-
puytren in a late volume of the Proceedings of the Na-
tional Institute of France,  that the oxygenation  or de-
carbonation of the blood is much affected, in respiration,
by an  influence  exercised  by the nerves which are ap-
propriated  to the lungs. From his account it appears,
that although the complete division of the eighth pair
of nerves produces death after some time; yet, in the
horse whose  nerves  are thus divided,  life continues,
and respiration goes on, from half  an hour  to ten hours;
but his arterial blood is in a state  of great disoxygena-
tion or carbonation, during this time___This fact is more
remarkable, because  venous blood, contained in a blad-
der exposed  to  the open air, will become oxygenated
or decarbonated.
  It is also asserted in another Memoir, read to the Na-
tional Institute by Dr. J. M. Provencal, that animals in
whom the eighth pair of nerves has been divided, do not 
    Effects of Venous Blood on the Heart.        73

consume so much oxygen, or produce so much carbonic
acid,  by a considerable  degree,  as  they did before the
division of these nerves; and that their temperature is
considerably. reduced.*
    The fact, that venous blood occasions death when it is ad-
      mitted into the left ventricle of the heart, and the aorta,
      is truly important.  Dr. Goodwin explained  it by sug-
      gesting that  this blood was not sufficiently stimulating
      to produce  the necessary excitement of the  heart; but
      on this occasion one of his friends proposed to him the
      following question:  Why does  venous blood affect the
      left side of the heart in this injurious manner, when it
      appears to exert no noxious  effects whatever  on the
      right side of that  organ?  His reply may be seen in a
      note at  the 82d page of his Essay, in the  first edition.
      Bichat  has  offered a solution  which  completely  re-
      solves this difficulty, viz. u The effect of venous blood
      upon the heart is produced by the presence of this blood
      in the proper, or coronary, arteries of that  organ, and
      not in its great cavities." For the animation of the heart,
      like that of  the other parts of the body, depends upon
      the state of the blood in the arteries which penetrate its
      texture.f  And while  the  heart  acts, the  blood of  the
      coronary arteries will  be the same with that of the left
      ventricle. See Bichat's Researches, P. II. art. 6, §2.
    The French Anatomists appear to entertain some peculiar
      opinions respecting the course of the* bluod in the foetus,
      which have a particular relation to the subject last men-
      tioned. Winslow, who paid great attention to the valve
      of Eustachius in the  right auricle of the heart, was of
      opinion, that this valve was calculated for  some impor-
      tant purpose  in the foetal economy4  Although his hy-

  * These Memoirs  are republished in  the Eclectic Repertory of
Philadelphia for April and October 1811.
  t It is  probable that the contents of the great cavities of the heart
have no  more effect upon its animation than the contents of the sto-
mach  and bowels have upon the animation of  those organs.
  \ See Memoirs of the Academy of Sciences for 1717 and 1725.
   Vol. II.                 K 
         Sentiments of Sabatier, &c.

pothesis  respecting its particular use has not  been re-
tained by his countrymen, many of them have adopted   i
his general sentiment; and among others Sabatier. That
learned anatomist believed that this  valve, in the foetal
state, serves to direct the blood of the inferior cava, after
its arrival in the right auricle, through the foramen ovale   ]
into the left auricle; while the blood  of the upper cava
passes directly into the right ventricle. His opinion seems   j
to be supported to a certain degree,                       •
   1. By the direction in which the two columns of blood
enter the auricle from the two vense cavse.
   2.  By the position of the Eustachian valve.
   3.  By the foramen ovale, when its valve is  complete;
 as the passage  through it, from the  right to the left, is
 at that time oblique, and from below  upwards.
   The theory of  Sabatier appears to be this: The  unv  j
 bilical vein brings from the placenta  blood which has a
 quality essential to the animation of the foetus.  If there
 were no particular provision  to the  contrary, a large
 portion of this blood, after passing  from the umbilical  $
 vein  by the inferior cava into the right auricle of the
 heart, would proceed by the right ventricle, through the
 pulmonary artery and arterial canal, into the aorta, below
 the origins of  the carotid and subclavian arteries;  and
 consequently none of it would pass to the head and upper
 extremities, but  a considerable part would return again
 by the umbilical arteries to the placenta, without circulat-
 ing through the body: while on the other hand, the blood
 which  passed by the carotid and subclavian arteries to
 the head and upper extremities, returning from them to
 the heart by the superior cava, might pass from the right
  auricle to the left auricle and ventricle and the aorta, and
  so to the head and upper extremities again, without pass-
  ing through the placenta.'. But by means  of this valve, the
  blood of the  lower cava, and  of Course  of the  umbilical
  vein, is directed to the left auricle and ventricle and the
  aorta, by which a considerable portion of it will necessa-
  rily pass to the  head  and upper extremities:  while the
  blood  which* returns from these  parts  by the supe-
  rior cava,  must consequently pass  from the  right au- 
            respecting the Foetal Circulation.           75

      ricle into the right ventricle and pulmonary artery; from
      whence  a large portion  of it will proceed  through the
      arterial canal into the aorta beyond the carotids and sub-
      calvians, and of this portion a considerable part will go
      to the placenta by the umbilical arteries. Sabatier com-
      pares the course  of the blood in the foetus to  the course
      of a fluid in a tube which has the form of the numeral
      character 8.*—If this doctrine  be true, the progress of
      the  blood in the  foetus and placenta is very  analogous to
      that of the double circulation of  the adult; the charaq|gr 8
      answering equally well in the description of  either sub-
      ject.
        According to Sabatier, the blood of the placenta takes
      this peculiar course through the heart, in order that some
      of it may be carried to the  head and upper extremities.
      But an additional reason may  be suggested, which ap-
      pears to be of great  importance;  viz.  the  supplying of
      the coronary or proper vessels of the heart  with some of
      the same blood.
        The heart of the adult, as has been before stated, cann
      not act without its proper  or coronary arteries are sup-
      plied with arterial  blood.  The heart  of the foetus per-
      forms  a  more extensive circulation than  that  of the
      adult, and therefore is probably in greater need of such
      blood. But unless the blood of the placenta passes through
      the foramen  ovale into the left  auricle and ventricle, and
      so to the aorta, it cannot enter the coronary arteries which
        riginate at the commencement of the aorta; for the blood
      which flows from the right side of the  heart through the
      arterial  canal, passes into  the aorta at so great a  dis-
      tance from the orifices  of the  coronary arteries, that it
      certainly cannot enter them.
        The whqle of  this doctrine seems to be supported by
      a fact, very familiar to accoucheurs, viz. the occurrence
      of  death in the foetus whenever the  circulation through
      the umbilical cord is suspended tluring fifteen or  twenty
      minutes: for  as  the  placenta imparts to the foetal blood

  * See  Sabatier's Paper on this subject in the Memoirs of the Aca-
demy of Sciences, for 1774.                            * 
Unusual Cases of Malformation.
a quality essential to  life, some arrangement seems ne-
cessary to provide for the  equal distribution of the
blood which  comis from this organ,  and especially for
carrying the requisite proportion of it to the substance
of the heart.
Life has existed for some time with a structure very dif-
  ferent indeed from that which is natural. In the series
  of elegant engravings relating to morbid anatomy, pub-
  lished by Dr. Baillie, is the representation of a heart,   j
  in which the vense cavae opened into the right auricle,
  and  the  pulmonary  veins  into  the left auricle,  in the   i
  usual manner; but the  aorta arose entirely  from the
  right ventricle, and the  pulmonary artery as completely
  from the left.—The  canalis arteriosus, however, passed
  from the pulmonary artery to the aorta, and the fora- jj
  men ovale existed. In  this case it is evident  that the
  pulmonary artery must  have carried  back to  the lungs
  tne  arterial blood which  came from them by the pulmo*  1
  nary veins, with a small  quantity of venous blood  that
  passed into the left auricle  through the foramen  ovale;  1
  and that  the aorta must have returned, to the body, the
  venous blood which  just before had been brought from   \
  it by the venae cavae, with  a small addition  of arterial
  blood that passed through  the  ductus  arteriosus. Yet,
  with this structure, the  child lived two  months after its
  birth.
    A case, which  had a strong resemblance to the fore-
  going, occurred lately in Philadelphia, and was examin-
  ed by the author of this  work. The venae cavae terminat-
  ed regularly in the  right  auricle, and the pulmonary   !
  veins in the same regular  manner in the left; but the
  pulmonary artery arose from the left ventricle, and the
  aorta from the right. There was  no communication be-   \
  tween these vessels by a canalis arteriosus; but a large   ,
  opening existed in the septum between the auricles.
    It is very evident, that in this case also the pulmonary
  artery must have returned to the lungs the arterial blood
  as it came from them, and the aorta must have carried   '■
  back to the general system the venous blood brought to 
Foramen Ovale,
77
the heart by the cavae; excepting only those portions  of
the arterial  and venous blood which must have flowed
reciprocally from  one auricle  into the other,  and thus
changed their respective situations.
   The subject was about two years and a half  old. The
heart was nearly double the natural size, and the fora-
men, or opening  in the septum between  the  auricles,
was eight or nine lines in diameter. The pulmonary ar-
tery was larger in proportion than the aorta or the heart.
   With  this organization  the child  lived to  the age
above specified. His  countenance was generally rather
livid; and this colour was always much increased by the
least  irregularity  of respiration. His nails were always
livid. He sometimes appeared placid,  but more fre-
quently in distress. He never Walked, and  seldom, if
ever, stood on his feet. When sitting on the  floor,  he
would sometimes push himself about the room; but this
muscular exertion always greatly affected  his respira-
ration. He attained the size common to children of his
age, and had  generally a  great  appetite.  For  some
weeks before death his legs and feet were swelled.
   It is  probable that the  protraction of life depended
upon the mixture  of the blood in the two auricles; and
that they really were to be considered as one cavity, in
this case.
There seems reason to believe, that in adults of the com-
  mon structure, there is no passage of blood from one
  auricle to the other, when the foramen ovale  has re-
  mained  open; because in several persons in whom it
  was found by dissection to have  remained open, there
  were no  appearances during life that indicated the pre-
  sence of  disoxygenated blood in the aortic system. It is
  pre bable, that the small size of the foramen ovale, the
  valvular  structure which generally exists there,  and the
  complete occupation of the left auricle  by the  blood
  flowing from the pulmonary veins, prevent  the passage
  of blood from the right auricle to the left, in such per-
  sons; whereas, in the case in question, the opening be-
  tween the auricles was  very large indeed, and there was
  no appearance of a valve about  it. 
78      On the Source of the Motion of the Heart.
  Although it be admitted, that in adults with the fora-
men ovale pervious,  there is no transmission of blood
from the right to the left auricle; there is every reason
to believe that this transmission goes on steadily in the
foetus.  To  the arguments, derived from the structure
and the  nature  of the  case, i< may be added, that the
pulmonary veins, in the foetal state, carry to the left au-
ricle a  quantity  of blood, not sufficient to fill it; while
the venae cavae  carry to the right auricle not only the
whole blood of the body, but of the umbilical cord and
placenta: some of which must flow into  the unfilled left
auricle, when the right auricle becomes fully distended.
     The question how far the functions of the heart and lungs
       are dependent upon the brain is  very important, and
       has often  been agitated with  great zeal. In favour  of
       the opinion that the motions of the heart are  inde-
       pendent of the brain, may be stated the numerous cases
       in which the  brain  has been deficient in  children, who
       have notwithstanding lived the full period of utero ges-
       tation, and even a short time after birth, and have ar-
       rived at their full size, with every  appearance of perfect
       vigour and action in the heart. In support  of the doc-
       trine, that  the action of the  heart is immediately de-
       pendent upon the brain,  it may be observed,  that no
       organ of the body appears to  be so much influenced by
       passions and other mental affections as the heart. These
       contradictory facts have occasioned this  question to be
       considered as undecided, if not  incapable  of solution;
       although Cruikshank and Bichat* have stated  circum-
       stances very favourable to the opinion that the  motions
       of the heart are independent of the brain.

  * See Cruikshank's Experiments  on the Nerves and Spinal Mar-
row of living animals; London Philosophical  Transactions for 1795.
The eighth experiment has a particular relation  to this subject.
  Bichat's Researches, part 2, article 9.
  The Abbe Fontana has considered this subject in his Treatise  on
the Venom of the Viper, vol. ii. page 194, English translation; and
also in some of his other works. 
   Humboldt and others on Legallois7 Paper.      79

    This question seems now to  be settled by the experi-
  ments of Dr.  Legallois, a physician of Paris, which
  prove, that in  animals who have suffered decapitation,
  the action  of the heart does not  cease as an immediate
  consequence of the removal of the head; but its cessa-
  tion is an  indirect effect, induced by the suspension of
  respiration. That respiration is immediately affected by
  decapitation, and depends  upon the  influence of the
  brain transmitted through  the  eighth pair of nerves.
  That the action of the heart will continue a long  time
  after decapitation, if  inflation of the lungs,  or  artificial
  respiration, be performed; but, on the contrary, if the
  spinal marrow be destroyed, the action of the heart
  ceases irrecoverably.
    The inference from  these experiments seems very
  conclusive, that the Spinal Marrow, and not the  brain, is
  the source of the motions of the heart.
    It appears also by  some of the experiments,  that the
  power of motion in the trunk of the body is derived from
  the spinal  marrow; and that when this organ is  partially
  destroyed, the parts  which receive nerves from the de-
   stroyed  portion soon  cease  to  live.  By particular man-
  agement of the spinal marrow, one part of the body can
  be preserved alive for some time after the other  parts are
  dead.
These experiments of Dr.  Legallois commenced  in  1806
% or 1807, and were communicated to the Imperial Insti*-
  tute of France in  1811. The  committee of that body
  to whom they were  referred, viz.  Messrs.  Humboldt,
  Halle and Percy, reported that the experiments had been
  repeated before them, at three different meetings of se-
  veral hours each;  and that to allow themselves  sufficient
  time for reflection, they suffered an interval of a week
  to take place between the meetings.  The committee be-
  lieve these experiments  to have proved,
    1st. That the principle upon which all the  movements
  of inspiration depend, has its seat about that part of the
  medulli oblongata from \?hich the nerves of the eighth
  pair arise.
    2d. That the principle  which animates each part of the 
80    Brodie on the Source of the Motion of the Heart.

      trunk of the body is seated in that portion of the spinal
      marrow from  which the nerves of the part arise.
         3d. That the source  of the life and  strength  of the
      heart is also in  the spinal marrow;  not in  any distinct
      portion, but in the whole of it.
         4th. That the great sympathetic nerve, is to be consi-
      dered  as originating in the spinal marrow, and that the
      particular character of this nerve is to place each of the
      parts to  which it is distributed under the immediate in-
      fluence of the  whole nervous power.
    The interesting memoir of Dr. Legallois is confirmed to a
      certain degree by a communication of B. C  Brodie to
      the Royal Society of London in 1810, in  which are  de-
      tailed many very interesting experiments which induced
      the author to conclude,—
         That the influence of the brain is not  directly  neces-
      sary to the action of the heart; and
         That when the brain is injured or removed, the ac-
      tion of the heart ceases, only because respiration is un-
      der its influence; and if under these circumstauces res-
      piration is artificially produced, the circulation will still
      continue.
    These various experiments apply particularly to the cases
      in which the brain  is  deficient. The effects  of mental
      agitations on the heart are likewise reconcileable  to the
      theory which  arises out of them.  But  they  throw no
      light on the question why the motions  of the heart are
      so perfectly free from the influence  of  the will: and al-
      though they seem to prove  incontestably that the mo-
      tion of the heart is independent of  the brain, it ought
      to be remembered that in certain diseased states of the
      brain, where that organ appears to be compressed, the
      action of  the heart is often very irregular, and its con-
      tractions less frequent than usual. 
SYSTEM  OF  ANATOMY.

          PART VIII.
               OF THE ABDOMEN.


THE lowermost of the two great cavities of the trunk
of the body is called Abdomen. The pelvis may be consi-
dered as a chamber of this cavity, although its structure is
very different.

                   CHAPTER I.
  A  GENERAL VIEW OF THE ABDOMEN AND PELVIS AND THEIR
    CONTENT8, WITH AN ACCOUNT OF THE PERITONEUM.

                   SECTION I.

                  Of the Abdomen.
  THIS great cavity occupies more than half of the space
inclosed by the ribs, and all the interior of the trunk of the
body below the thorax.
  It is formed by the diaphragm, supported by the lower
ribs; by a portion of the spine;  by the various muscles
which occur between the lower margin of the thorax and
the upper margin of the ossa innominata; and by the ossa
innominata, which contribute, for the purpose, the costs of
the ossa ilea, as well as the pelvis..
   Vol. II.              L 
82           Construction of the Abdomen.

  The general figure of this cavity partakes of the figure
of the lower part of the trunk of the body; with these ex-
ceptions, that the diaphragm makes it arched  or vaulted
above, that the spine and psoas muscles, &c. are rather
prominent on the posterior surface, and  that the lower
part corresponds  with the costse of the ossa ilea and  with
the pelvis.
  To acquire a precise idea of this cavity, it is necessary
first to study the  bones concerned in its structure, in  their
natural situation  in the skeleton;  and then  the muscles,
which form so large a  part of it.
  The arrangement of the tendons of some of these mus-
cles, with a view to complete  the cavity, is particularly
interesting;  as that of the external oblique when it forms
the crural arch.* The  ligaments of the pelvis and the le-
vatores ani muscles, as they also contribute to the forma-
tion of the cavity, and have an influence upon its figure,
should likewise  be attended to.
  In  the walls of the cavity, thus constructed, there are
man) foramina by which the viscera and other contained
parts  communicate externally;  but few of them  pass di-
rectly into the cavity; for like the thorax, there are no va-
cuities in it exterior to the contained organs.
  Three of these foramina are  in the diaphragm.  One for
the transmission  of  the aorta, another for the vena cava,
and a third for the oesophagus. Below, there is an aperture
at each of the crural arches, for the  transmission of the
great femoral vessels;  in each  of the ligamentous mem-
branes, which close the foramen thyroideum, for the obtu-
rator  vessels and  nerve; and at  the sacro sciatic notches,
for nerves and bloodvessels.
  There are also two apertures at the  bottom of the pel-
vis, for the orifice of the rectum and of the urethra. In the
tendons of the external oblique muscles are two orifices,

  * See the account of this tendon, vol. i. in the  description  of the
li Obliquus Decendens Lxternus." 
            Construction of the Abdomen.           83

covered by the integuments, for the spermatic cords; and,
in the foetal state, one for the umbilical cord.
   The apertures in the  tendons,  and under their edges,
for the transmission of the spermatic cords, and the blood-
vessels, &c. are not to be considered as simple perfora-
 tions made abruptly; but the edges of these foramina are
 formed by tendinous membranes turned inwards and con-
 tinued so'as to compose a cylindrical tube, which becomes
 gradually so thin that it  cannot be readily distinguished
 from the cellular membrane with which it is connected.*
 The bloodvessels, &c. pass along this tube before they go
 through the apertures.
   It is evident from  the construction of this cavity that
 it is essentially different from the thorax.  It has no power
 of spontaneous dilatation whatever:  it yields passively to
 the distension of the stomach and intestines, during deglu-
 tition, and when air is extricated  from the aliment, &c;
 but it is  particularly calculated for compressing its con-
 tents by the contraction of the muscles which compose it.
 The diminution of its capacity,  which is thus  effected,
 not only takes place to a  great degree, but occasionally
 with great force. The diaphragm and the abdominal mus-
 cles may be considered in some  measure as antagonists
 of each other.  When the diaphragm descends, if the ab-
 dominal  muscles  are passive, they are  distended by the
 contents of the abdomen, which are forcibly pressed from
 above; but if the abdominal muscles act at the same time,
 an effort to diminish the  cavity in  every direction  takes
  place, and the contained parts are compressed with more
  or less force  according to the exertion made. This will
  be very evident upon examining  the situation of the dia-
  phragm and of the abdominal muscles.  When their force

    * The student of anatomy, when engaged with  this subject, will
  be gratified by the examination of Mr. Astley Cooper's plates rela-
  ting to hernias. 
84             Contents of the Abdomen.

is considered it will also be very obvious that the various
outlets of the cavity are constructed most advantageously;
otherwise hernia or protrusion of its.contents would be a
daily occurrence.
  The abdomen contains, 1st. The Stomach and the whole
Intestinal Tube, consisting of the small and the great in-
testines.
  2d. The Assisting Chylopoietic Viscera,—the Liver, the
Pancreas and the Spleen.
  3d.  The Urinary Organs,—the Kidneys, the Ureters,
and the Bladder. To which should be added the Glandu-
lar Renales.
  4th. The Organs of Generation  in  part: those of the
female sex  being  almost  wholly included in the pelvis;
and those of the male being situated  partly within  and
partly without it.
  5th. The  Peritoneum and  its various processes. The
Mesentery, Omentum, &c.
  6th. A portion of the Aorta, and almost the whole of the
Inferior Cava, and their great ramifications; with such of
their branches as are  appropriated to the  Viscera of the
Abdomen and Pelvis.
  7th. Those portions  of the Par Vagum  and Intercostal
Nerves which are appropriated to the cavity; and portions
of some of the nerves destined to the lower extremities.
  8th. The lower part of the Thoracic Duct, or the Great
Trunk of the Absorbent System, with the  large branches
that compose it, and the glands connected  with them; and
also those absorbent  vessels called  Lacteals, and their
glands.
  As the cavity of the abdomen has no natural divisions,
anatomists have divided it by imaginary lines into various
regions, with a view to precision in their accounts of the
situation of the different contained parts.  Thus,
  They have, very generally, agreed to apply two trans-
verse lines to form three great divisions; viz. the  Upper, 
               Regions of the Abdomen.             85

Middle and Lower: and they have also agreed that each of
these divisions shall be subdivided into three regions.
  The three regions of the uppermost division are defined
with some precision. Those on each side, which are called
the Right and  Left  Hypochondriac regions,  occupy the
spaces immediately within the lower ribs and their carti-
lages; while the middle space, included within the margins
of these cartilages, and a line drawn from the lower edge of
the thorax on one side to that on  the other, is denomina-
ted the Epigastric region.
   The boundaries of the regions  below are less precisely
defined.
   Many anatomists have  fixed the two  transverse lines
above mentioned at an arbitrary distance above and below
the umbilicus: some choosing for this purpose two inches,
and others a hand's breadth. As these distances will occu-
py different proportions of the cavity in persons of differ-
ent stature, other anatomists, with a view to avoid this
inconvenience, have proposed to  connect these  lines with
certain fixed points of the skeleton.
   It is of importance that the boundaries of these  regions
should be fixed, and therefore the proposition of Sabatier
may be adopted; viz.  To draw the upper transverse line
from  the most inferior part of the lower nvirgin of the
 thorax, on one side, to the corresponding part on the oppo-
site side; and the lower transverse  line from  the upper-
 most part of the spine of one ileum to the  same part of the
 other. These lines will mark the three great divisions. If
 then  two parallel lines  are drawn directly upwards, one
 from each of the superior anterior spinous processes of the
 ileum until it touches the  lower margin of the thorax,
 they will divide each of the two lower  divisions of the
 abdomen into three  regions.  The  center of the middle
 division is the umbilical, and on each side of it is the right
 and left lumbar region. The middle of the lower division 
 86         Situation of the Viscera, fc?c. in the

 is the  hypogastric; and on each side of  it the right and
 left iliac region.
   It is true, that the three middle regions of the abdomen
\vill be made very small by the vicinity of the transverse
 lines to each other; but the advantages derived from a
 principle which is similar in its application to all subjects
 fully compensates this inconvenience.
   There are  therefore  nine of these regions: viz. The
 Epigastric  and the two Hypochondriac: the  Umbilical,
 and the two Lumbar: the Hypogastric, and the two Iliac
 regions.* And it should be added, that  the space imme-
 diately around the end  of the sternum is sometimes caU
 led  the  Scrobiculus Cordis;  and the space  immediately
 within the os pubis, the Regio Pubis.
   These different regions  are  generally occupied in the
 following manner. The liver fills nearly the whole of the
 right hypochondriac region, and extends through the up-
 per part of the epigastric region into the left  hypochon-
 driac. The stomach occupies the principal part of the epi-
 gastric region, and a considerable portion of the left hy.
 pochondriac. The spleen is also situated  in the left hypo-
 chondriac region.  That portion of  the  intestinal  tube,
 which is composed of  the small intestines, is generally
 found in tile umbilical, the hypogastric, and the iliac  re-
 gions; and when the bladder is empty, in the pelvis. But
 the duodenum, or first of the small intestines,  which pro-
 ceeds immediately from the  stomach,  is situated in  the
 epigastric and  umbilical  regions.  The  great intestine
 commences in or near  the right iliac region, and ascends
 through the right lumbar to the right hypochondriac re-
 gion.  It then crosses the abdomen,  passing through  the
 lower part of the epigastric, or upper part of the umbilical

   * It is to be observed that the  lateral regions of  the middle and
 lower  divisions of the abdomen are named differently by different
 writers. 
                Cavity of the Abdomen.              87

to the left lumbar region; from this it continues into the
leit iliac region, and curves in such manner that it finally
arrives at the middle of the upper part of the os sacrum,
when it descends into the pelvis, and, partaking  of the
curvature of the last mentioned bone,  continues  to the
termination of the os coccygis.
   In  the  back  part of the epigastric region,  and  very
low down in it, is situated the pancreas. The kidneys lie
in the most posterior parts of the lumbar  regions, and
from  each of them is continued a tube or duct,  called
Ureter,  that passes into the pelvis  to convey the urine to
the bladder. This viscus, in males, is in contact with the
last portion of the great intestine called the Rectum, and
with it  occupies almost all of the cavity of the pelvis;
while in  females,  the  uterus and its appendages  are
situated between  this intestine and the bladder.
   In the posterior part of the abdomen, in contact with
the spine, is the aorta.  This great  bloodvessel  passes
from  the  thorax  between the crura  of the diaphragm,
and continues down the spine until it approaches towards
the pelvis, when it divides into two great branches called
the Iliac Arteries. Each  of these great branches divides
again, on the side of the pelvis, into  two; viz.  the Ex-
ternal Uiac, which  passes under the  crural arch  to the
thigh, and the Internal Iliac,  or Hypogastric, which  de-
scends into the cavity of the pelvis.
   Soon  after the arrival  of the aorta in the abdomen it
gives off two large branches. The first, which is  called
the Coeliac, is distributed to the liver, the stomach, and
the spleen:  the second,  called the Superior Mesenteric,
is spent upon the intestines. Lower down, in the abdo-
men,  it also sends  off-a small branch for the intestines,
called the Inferior Mesenteric. Besides these vessels for
the chylopoietic  viscera, jthe aorta  sends of  a  large
branch,  called Emulgent,  to each kidney.
  .The inferior,  or  ascending vena cava,  is situated on 
88
The Peritoneum.
 the right of the aorta, in front of the spine. It is formed
 below by the union of the iliac veins, and in its progress
 upwards it receives the  emulgent. veins, which corres-
 pond to  the arteries of the kidneys; but  it receives in
 its course no veins which correspond  directly with the
 coeliac and mesenteric  arteries. The smaller veins, that
 answer to  the branches of these arteries, unite and form
 one  large  vein, which  goes to the liver, and  is called
 (from the  part of that viscus  at  which it  enters) Vena
 Portarum. From the liver three large veins pass into the
 vena  cava, and deposit there the blood of the vena por-
 tarum, after it has furnished materials for the secretion
 of bile.  The vena cava, in its passage upwards, is in
 close contact with the posterior thick edge of the liver:
 it  often  passes along a  deep groove in this edge, and
 sometimes it is completely surrounded by the liver in its
course. The veins of the liver enter the vena cava at this
place, and of course they are not to be seen without dis-
section.  Immediately  after leaving the liver the vena
cava passes through an aperture in the tendinous  center
of the diaphragm to unite itself to the right auricle of the
heart.
                     SECTION II.

                  Of the Peritoneum.
  THE  abdomen, thus constructed and occupied,  is
lined by a thin firm membrane called Peritoneum, which
is extremely smooth  on its  internal surface, and is inti-
mately connected with the  cellular  substance exterior to
it. This membrane adheres closely to the anterior, lateral,
and superior portions of the surface of the abdomen; and
is  extended from  the posterior surface  so as  to  cover, 
The Peritoneum.                 89
more or less completely, the viscera of the cavity. Those
viscera which are in close contact with the posterior sur-
face of the abdomen, as some  portions of the large in-
testine, are covered only on their anterior surfaces, and
are fixed in their precise situations by the  peritoneum;
which extends from them to the contiguous surface of
the cavity, and adheres where  it is in contact, so as to
produce this effect.
   Other viscera,  which are not in  close  contact, but
moveable to a distance from the posterior surface of the
abdomen, are covered by this membrane, which is extend-
ed to them from the surface; and this extended portion
forms an important part of the connexion  between the
viscus and the cavity in which it lies. This connecting
part is called Mesentery, when it thus passes to, the small
intestines; Mesocolon, when  it goes to the colon, one of
the larger intestines;  and Ligament, when it passes to
some of the other viscera.
   The peritoneum is a complete but empty sac, which
is fixed in the abdomen anterior to  the viscera.  The an-
terior portion of this sac forms  the lining  to the ante-
rior and lateral parts of the  surface of the abdomen; the
posterior portion covers the viscera, and forms the mer
sentery, mesocolon, and ligaments above described.
   It necessarily follows that the mesentery and the other
similar processes are mere plaits or folds of the sac, which
invests the viscera;  and that they must consist of two la-
minae: and as the bloodvessels, nerves, and absorbents,
are all  posterior to the peritoneum, they naturally pass
between these laminae of the mesentery.
   Some of the viscera are much more completely invest-
ed with the peritoneum than others. The stomach, liver,
and spleen, are almost  completely surrounded by it; and
it is said to  form a coat for each of these viscera. That
portion of the smaller intestinal tube, which is called je*
junum and ileum, and the transverse portion of the large
   Vol. II.              M 
90
The Peritoneum.
intestine, called the arch of the colon, are invested by it
in the same way. But a considerable portion of the duo-
denum and the pancreas is behind  it. The later.il portions
of the colon are in  close contact  with the posterior sur-
face of the abdomen, and the peritoneum only covers that
portion  of their surfaces which looks  anteriorly towards
the cavity of the abdomen, and is not in contact with its
posterior surface.
   The  urinary organs are not much connected with the
peritoneum. The kidneys appear exterior to it, and be-
hind it:  the  bladder of urine is below it,  and has but a
partial covering from it, on its upper portion.
   The  peritoneum, which  covers the stomach, is  ex-
tended from the great curvature  of that organ so as to
form a  large membrane, which descends like an apron
before the intestines. This process of peritoneum is com-
posed of two laminae, so thin and delicate as to resemble
cellular membrane,  which,  after  extending  downwards
to the lower part of the abdomen, are turned backwards
and upwards, and  proceed  in that direction until they
arrive at the colon, which they inclose, and then continue
to the  back of the abdomen, forming the  mesocolon.
The part of this  process which is between the stomach
and the colon, is called Epiploon, or Omentum.
   This extension of a membrane,  from the  surface  of a
cavity which it lines to the external surface of a viscusin
that cavity, is called, by some anatomists, "reflection;"
and the technical term reflected membrane is therefore ap-
plied to a membrane distributed like the peritoneum.
   It must be evident that this distribution of the perito-
neum is very complex, and that it is not easy to form an
accurate conception of it from description, but it can be
readily  understood by demonstration;  therefore no fur-
ther account of its  arrangement  will now be attempted,
 but each of its processes will be  considered with the or-
 gans to which they are particularly subservient. 
The Peritoneum.                 9\
  That portion of the peritoneum which lines the abdo-
men and covers the viscera is thin and delicate, but very
firm.  It yields to distention, as in pregnancy, ascites, &c;
and again recovers its dimensions. It was formerly thought
to be composed of two lamina;, but this cannot be proved.
The internal surface of this membrane  is very smooth,
and  highly polished; and from it exudes a liquor which
is well calculated for lubrication, and barely sufficient to
keep the surface moist during health; but sometimes it is
very abundant, and occasions the aforesaid disease—as-
cites. This fluid appears to exude from the surface of the
peritoneum when it is compressed in a living animal, or
in one  recently dead. It is probably effused from  the ex-
tremities of arteries, for an effusion takes place when water
is injected into these vessels.
  The peritoneum abounds with absorbent vessels, and
therefore possesses the power of absorption to  a great de-
gree. This power may be inferred, not only from the spon-
taneous  removal of the fluid  of ascites, but if milk and
water be introduced into the abdomen of a living animal,
through  a puncture, it will  also disappear.
  The bloodvessels of the peritoneum are derived from
those which supply the neighbouring parts.  Nerves have
not yet been traced into it, and it has little or no sensi-
bility.
  This membrane supports the viscera of the abdomen in
their proper situations; and also forms a surface for them,
and for the cavity which contains them, so smooth and lu-
bricated, that  no injury can arise from their friction.
   The cellular substance,  by which the peritoneum is
connected to the contiguous parts, is very different in dif-
ferent  places.  It is very short indeed between this mem-
brane  and the  stomach and intestines, and also between it
and the tendinous center of the diaphragm. Between the
peritoneum and the muscles generally, it is much longer. 
92
The Peritoneum.
When it covers the kidneys and the psoas muscles it is
very lax and yielding. About the kidneys a large quan-
tity of adeps very commonly collects in it. On the psoas
muscle it yields with but little resistance to the passage of
pus, or any other effused fluid, as in the case of the psoas
abscess. 
93
                    CHAPTER II.

 OF THE OESOPHAGUS, THE STOMACH, AND THE INTESTINES.

                    SECTION I.

                 Of the (Esophagus.

THE CEsophagus is a muscular tube which passes from
the pharynx to the stomach, and is so intimately connected
with the stomach, that it will be advantageous to the stu-
dent to attend to its structure immediately before he en-
gages in the examination of that important organ.
  The pharynx has been lately described* as composed of
a varied stratum of muscular fibres, lined by a membrane
which is continued from the internal surface of the nose
and mouth. From the pharynx  the oesophagus passes
downwards between the trachea and the vertebrae. After
the bifurcation of the trachea, it proceeds in contact with
the spine, between the laminae of the mediastinum, to the
diaphragm, which it passes  through, and then terminates
in the stomach.
  The oesophagus is a flexible tube, which, when distend-
ed, is nearly cylindrical. It consists of a muscular coat
externally,  and an internal tunic evidently continued from
that of the  pharynx.  These coats are connected by a cel-
lular substance called the Nervous Coat, which is remark-
ably loose,  and allows them to move considerably upon
each other.  The muscular coat, which is very distinguish-
able from that of the pharynx, consists of two substantial
strata of fibres; the exterior of which is nearly longitudi-
nal in its direction, and the anterior circular or transverse.
•See page 37. 
94
The CEsophagus.
   The internal coat of the oesophagus, resembling that of
the fauces, is soft and spongy. It is  covered with a very
delicate cuticle, which Haller supposed to be too tender
to confine the matter of variolous pustules, as he had never
found these extending into the oesophagus. It is very vascu-
lar, and abounds with the orifices of mucous follicles, from
which is constantly poured out the mucus that is spread
over this surface. When the oesophagus  is not distended,
many longitudinal plaits are found in this membrane by
the contraction of the circular or transverse fibres exterior
to it. These plaits are calculated to admit readily of the
distention which is requisite in deglutition. This tunic is
continued from the lining membrane of the pharynx above,
and terminates below in the villous coat of the stomach;
from which, however, it is  very different.
   The bloodvessels of the  oesophagus come from those
which are in the vicinity. The nerves are derived  from
the eighth pair.  The lymphatic vessels are very abundant.
   In the neck, the oesophagus inclines rather to the left of
the middle line. As it proceeds down the back between
the laminae of the  mediastinum, it  preserves the same
course to the fourth dorsal vertebra,  when it assumes the
middle portion and proceeds downwards, with the  aorta
to its left, and the pericardium before it. About the ninth
dorsal vertebra  it inclines again rather to the left, and
somewhat forward, to arrive  at the aperture in the dia.
phragm through which it passes.
   Throughout this course it is connected by cellular mem'
brane to the contiguous parts;  and this investiture of cel-
lular membrane has been called its External Coat.
 .  While the oesophagus is  in the posterior mediastinum,
it is in contact with several small absorbent glands, espe-
ciaUy when it first assumes  a situation to the right of the
aorta. These glands were formerly believed to be parti-
larly connected with this tube, but they are now consi-
dered as belonging to the absorbent system. They are
sometimes greatly enlarged. 
Form of the Stomach.
95
                     SECTION II.

                   Of the Stomach.
  THIS most important  organ, which occasionally ex-
erts a  powerful  influence  upon  every part of the body,
appears very simple in its  structure.
  It is a large sac, which  is so thin when much inflated,
th.it at first view it seems  membranous, but upon exami-
tion is found to be composed of several laminae or coats,
each of a different structure. It is of considerable length,
but incurvated.  It is much larger at one extremity than
the other, and changes so gradually in this respect, that
it would appear conical if it were straight. It is not, how-
ever,  strictly conical,  unless it  is greatly distended; for
when moderately distended, a transverse section is rather
oval than  circular.  It is therefore considered as having
two broad sides or surfaces,  and two edges, which are
the curvatures.  It has been compared by the anatomists
of different nations  to the wind sac of the musical  in-
strument called the bag-pipe.*  The orifice in which  the
oesophagus terminates is at a small distance from its largest
extremity, and is called Cardia.  The orifice which com-
municates with the intestines is at  the termination of its
small incurvated extremity, and is called the Pylorus.
   The two ends of the stomach being thus very different
in size, are denominated the great and small extremities.
The two curved portions of the  surface are also called the
great and small curvatures. The two flat portions of the
surface, or the broadsides, are called the anterior and pos-
terior surfaces.
   The situation of the stomach  in the abdomen is nearly

  • The student ought not to attempt to acquire an idea of the form
of the  stomach without demonstration, for a view of one moment
will be more serviceable than a long description. 
96            Position of the Stomach.

transverse: it lies principally in the  left  hypochondriac
and the epigastric regions, immediately below  the liver.
The great extremity of the stomach is in the left hypo.
chondriac region, and the lesser extremity in the epigas-
trie region, under the  left lobe of the liver. The upper
orifice, or Cardia, is nearly opposite to the  body of the
last dorsal vertebra; and, owing to the curved form of the
stomach,  the other orifice, or  Pylorus,  is situated at a
small distance to the right of that bone, and rather lower
and more forward than the cardia: both orifices being in
the epigastric region.  The position of the stomach is ob-
lique in two respects;  it inclines in a small degree from
above downwards, from the left to the right; and it also
inclines downwards and forwards, from  behind. Its two
orifices are situated  obliquely with respect to each other;
for, if the stomach, when placed with its small curvature
upwards,  were divided into two equal parts by a vertical
plane passing lengthways through it, they would be found
on different sides of the plane.
  As the  oesophagus terminates in the stomach immedi-
ately after it has passed through an aperture of the dia-
phragm, it is evident that the stomach must be somewhat
fixed at that place;  but it is more moveable at its other
orifice;  for the extremity of the duodenum, into which it
is continued, is moveable.
  The stomach  is  connected to  the  concave  surface of
the liver by the reflexion or continuation of the peritone-
um, which forms the lesser omentum. This membrane,
after extending  over each surface of the stomach, con-
tinues from its great curve in the form of the large omen-
tum, and connects it to different parts,  especially to the
colon. There are likewise folds of the peritoneum, as it
passes from the diaphragm  and from the spleen to the
stomach, which  appear like ligaments.
  Notwithstanding these various connections,  the sto-
mach undergoes considerable  changes  in  its  position. 
External Coat of the Stomach.           97
When it is nearly empty,  and the intestines  are in the
same  situation, its broad surfaces are presented forwards
and backwards; but when  it is distended, these surfaces
are presented obliquely upwards and downwards, and the
great  curvature forwards.  When its anterior surface is
presented upwards, its orifices are considerably influenced
in their direction, and the oesophagus forms an angle with
the plane of the stomach.
   The stomach is composed of four dissimilar laminae,
which may be  demonstrated by a simple process of dis-
section.
   There is first a coat  or  external covering continued
from  the peritoneum: within this, and connected to it by
delicate cellular substance, is a coat or stratum of mus-
cular  fibres: contiguous to these fibres,  internally, is  a
layer  of dense cellular substance, called a nervous coat;
and last is the internal coat  of the stomach, called villous,
or fungous, from the structure of its surface.
   The external or first coat of the  stomach, as has been
already stated, is  continued from the concave  surface of
the liver to the lesser curve of the  stomach  in two deli-
cate laminae, which separate when they approach the sto-
mach, and  pass down, one on each side  of it, adhering
firmly to it in their course: at the opposite  curve of the
stomach  they again  unite to form  the great omentum.
The stomach is therefore closely invested by the perito-
neum on every part of its surface except two strips, one
at the lesser and the  other at the greater curvature, These
strips or uncovered  places are formed by the separation
of the laminae above mentioned, which includes a trian-
gular  space bounded by the stomach and  these two la-
minae. In these triangular  spaces,  at each curvature of
the stomach, are situated  the  bloodvessels which  run
along the stomach in those directions, and also the glands
which belong to the absorbent vessels of  this viscus.
Tjie peculiar arrangement of  the laminae, at this place is
  Vol. II.                N 
98   Muscular and Nervous Coats of the Stomach.

particularly calculated to permit the dilatation of the sto-
mach.  When it is dilated the laminae are in close contact
with its surface, and the bloodvessels being  in the angle
formed by the adhesion of the two laminae to each other,
are so likewise: when it contracts,  the  bloodvessels ap-
pear to recede from it, and the laminae are then applied to
each other.
   Where the peritoneum thus forms a coat to the sto-
mach,  it is  stronger and thicker than it is between the
liver and stomach.  In a recent subject  it is very smooth
and moist, but so thin  that the muscular fibres, bloodves-
sels, &c. appear  through it. If it  is carefully dissected
from the muscular coat, it appears somewhat flocculent
on that surface which adhered to the muscular fibres. It
seems  to be most abundantly furnished with serous ves-
sels; but it has been asserted by Mascagni and Soemmer-
ing, that a large proportion  of its texture consists of ab-
sorbent vessels. The cellular substance which connects
this to the muscular coat appears no way different from
ordinary cellular  membrane.
   The Muscular  Coat of the stomach has been described
very differently by respectable anatomists; some consider-
ing it as forming three strata of fibres, and others but two.
If the stomach and a portion of the oesophagus attached to
it be moderately distended with air, and the external coat
carefully dissected away, many  longitudinal fibres  will
appear on every part of it, that evidently proceed  from the
 oesophagus: these fibres are particularly numerous and
 strong on the  lesser curvature of the stomach. Beside the
longitudinal fibres there are many that have a circular di-
rection, and these are particularly numerous towards the
 small extremity;  but it has been doubted  whether there
 are any fibres in the muscular coat of the stomach that go
 directly round it. The whole surface of the stomach, when
 the peritoneal coat is removed, appears at first view to be
 uniformly covered by muscular fibres; but upon close ex- 
Internal Coat of the Stomach.          99
amination there are interstices perceived, which are occu-
pied with firm cellular membrane.
   In contact with  the internal  surface of the muscular
coat is the cellular stratum, which has been  called the
Nervous Coat of the stomach. It  is dense and firm, of a
whitish colour, resembling condensed cellular membrane.
It was considered as different from ordinary cellular
membrane; but if  air be insinuated into its texture, by
blowing between the muscular and villous coats, while it
connects them to each other,  it exhibits the proper  ap-
pearance of cellular substance. It however adds greatly to
the general strength of the stomach, and the vessels which
terminate in the villous coat ramify in it.
   The internal coat of the stomach in the dead subject is
commonly of a whitish colour, with a tinge of red.  It is
named villous, from its supposed resemblance to the sur-
face of velvet. It has also been called fungous, because the
processes analogous to the villi are extremely short, and
its surface has a granulated appearance; differing in these
respects from the internal surface of the intestines.  It is
continued from the lining membrane of the oesophagus,
but  is very different  in  its structure. Many  very small
vessels seem to enter into its texture, which are derived
from branches that  ramify in the nervous  coat. It is sup-
posed by several anatomists of  the highest authority, to
have a cuticle or epithelium; and it said that such a
membrane has  been separated by disease. It ought how-
ever, to be remembered, that the structure of the villous
coat of the stomach  and intestines, is essentially different
from the structure of the cuticle.
   The internal coat  of the stomach is generally found co-
vered, or spread over, with mucus, which can be readily
scraped oft".  This mucus is certainly effused upon it by
secreting organs, and it has been supposed  that there were
small glandular bodies exterior to the villous coat,  which
furnished this secretion; but the existence of such bodies 
100
Gastric Liquor.
is very doubtful, as many skilful anatomists have not met
with any appearance that could be taken for glands, except
in a very few instances,  which  Would ndt be the case if
those appearances had been natural. Pores,  perhaps the
orifices of mucous follicles, and also of exhalent vessels,
are very numerous; but  no proper glandular masses  are
attached to them.  Glands, as have been already said, are
found in the triangular spaces between the laminae of the
peritoneum  at the great and small curvatures of the sto-
mach, but these evidently belong to the absorbent system.
Besides the mucus above mentioned, a large quantity of a
different liquor, the proper Gastric Juice, or fluid of  the
stomach, is  effused from its surface. It has been supposed
that this fluid is furnished  by the  small glandular bodies
believed to  exist between the coats of this organ; but,  ad-
mitting the  existence of these glands, they are not  suffi-
ciently  numerous to produce so much  of it as is found,
and it is therefore probable  that this fluid is discharged
from the orifices of exhalent vessels in the  internal surface.
   Much information  respecting the  gastric  liquor  has
been  obtained within a few years past by the researches
of physiologists, and they are generally agreed  that it is
the principal agent in the  effects produced  by the sto-
mach upon  alimentary substances.*

  * On this subject the student may consult with advantage,
  M. Reaumur. In the Memoirs of the Academy of Sciences for
1752.
  John Hunter. London Philosophical Transactions for  1772; and
also his observations on the Animal Economy, 1786.
  Dr.  Edward  Stevens. Inaugural Thesis de Alimentorum Con-
coctione. Edinburgh, 1777.
  The Abbe Spalanzani. Dissertations relative to Natural History, &c.
The first volume of the English translation contains the author's
dissertations on digestion, and also the first paper of Mr. Hunter,
and the Thesis of Dr. Stevens, as well as an account of the experi-
ments of Mr. Gosse of Geneva.
  In addition  to these, there are  several interesting essays in the 
The Pylorus.
101
  As the muscular coat of the stomach frequently varies
its dimensions, the villous and nervous coats, which have
ho such power of contraction, cannot exactly fit it. They
therefore  generally  appear  larger, and  of course are
thrown into folds or  rugae. These folds are commonly in
a longitudinal direction; but at  the Orifices of the  sto-
mach they are arranged in a radiated manner, and some-
times they are  observed in a transverse direction. They
depend upon the contraction  of  the muscular fibres, and
disappear entirely when the stomach is laid  open and
spread out.
  At the lower orifice is a circular fold, which is  perma-
nent, and constitutes the valve  denominated Pylorus. It
appears like a circular septum with a large foramen in its
center, or like a flat ring. The  villous and nervous coats
of the stomach contribute to  this, merely by forming the
circular fold or ruga;  and within this fold  is a  ring of
muscular fibres,  evidently connected with the  circular
fibres of the muscular coat of the stomach, the diameter
of which at this place is not  larger than that of an intes-
tine: the fibres of this ring seem a part of  the muscular
coat projecting into  the cavity of the stomach and duo-
denum.  If a portion of the  lesser extremity of the sto-
mach and the adjoining part of the duodenum be  detach-
ed, and  laid open by  a longitudinal  incision, and  then
spread out  upon a board, the internal coat can be very
easily dissected from the muscular, and the pylorus will
then  appear like a ridge or narrow bundle  of  muscular
fibres, which runs across the extended muscular mem-
brane. It is evident  that when the parts are replaced so
as to form a cylinder,  this narrow faciculus will form  a
ring in it. Thus arranged, the circular fibres can readily
close the lower orifice of the stomach.

French, German, and Italian languages, a compilation of which  is
to be found in Johnson's " History of the progress and present state
of Animal Chemistry."  See Vol. I. page 180. 
 102     Lymphatics and Nerves of the Stomach.

   The pylorus separates the stomach from the intestine
 duodenum; and this separation is marked exteriorly by a
 small  circular  depression,  which  corresponds  exactly
 with the situation of the pylorus.
   The arteries of the stomach are derived  from the
 Cozliac,  the first branch which the aorta sends off to the
 viscera of the abdomen.  This great  artery, immediately
 after it leaves the  aorta, is divided into  three branches,
 which are distributed to  the stomach,  the liver, and the
 spleen, and are called the Superior Coronary or Gastric,
 the Hepatic, and the Splenic. Besides the first mentioned
 branch,  which is   distributed  principally to  the neigh-
 bourhood  of the cardia and  to the lesser curvature, the
 stomach receives a considerable branch from the hepatic,
 which passes along the right portion of its great  curva-
 ture, and has been called the right gastroepiploic, and
 another from the spleen, which passes along the left por-
 tion of the great curvature, and has  been called  the left
 gastro-epiploic. In addition to these branches, the  splenic
 artery, before it enters the spleen, sends off several small
 arteries to the great extremity of the  stomach, which are
 called  vasa brevia.
   These vasa brevia generally arise from the main trunk
 of the  splenic artery, but sometimes from its branches.
   The veins which receive the blood from these arteries
 have similar names, and  pursue  corresponding courses
 backwards; but they terminate in the vena portarum.
   The absorbent vessels of the stomach are very numer-
 ous and large:  they pass to the glands which are  on the
 two  curvatures, and from thence to the thoracic duct.  It
 is an important fact relative  to the history of digestion,
 that there are good reasons  for doubting whether chyle
 commonly passes  through them, notwithstanding their
 number and size.*

  * Sabatier, however, in one subject  observed white lines on the
stomach, which he suspected to be lacteals.  See, his account of the
absorbents of the stomach. 
              The Intestines in general.           103

  The nerves of the  stomach are derived  principally
from  the two  great branches  of  the  par vagum, which
accompany the oesophagus  and are mostly spent upon
this  organ. It also receives  branches from several plex-
uses, which are derived from the  splanchnic portions of
the intercostal nerves.
                    SECTION  III.

                  Of the Intestines.
  THE  intestines form a continued canal from the py-
lorus to the anus, which  is generally six times the length
of the subject to which  they belong. Although the  diffe-
rent parts of this  tube  appear  somewhat different from
each  other,  they agree  in their general  structure. The
coats or laminae of which they are composed are much
like those  of the  stomach, but the peritoneum which
forms their external  coat  does not approach them in the
same manner; nor is it  continued  in the  form of omen-
tum from the whole tube, there being only a certain por.
tion of intestine, viz. the  colon, from which such a pro-
cess of peritoneum is continued.
  The Muscular Coat, like that of the  stomach, consists
of  two strata, the exterior of which is composed of lon-
gitudinal fibres, which adhere to the external coat,  and
do  not appear very strong. The other stratum, consist-
ing of circular  or transverse  fibres, is stronger, as the
fibres are more  numerous. It is observable that they ad-
here to  the longitudinal fibres: and they seldom if ever
form complete circles.
   The cellular  substance immediately within  the mus-
cular fibres resembles the nervous coat  of the stomach
in  its firmness  and  density. It is likewise so arranged 
104         Villous Coat of the Intestines.

as to form  many circular ridges on its internal  surface,
which support to a certain degree the permanent circu-
lar plaits of the internal coat, called valvulae conniventes.
   The inner surface of the internal coat has been com-
monly compared to that of velvet, and the coat is there-
fore called villous; but there is certainly a considerable
difference between these surfaces; for if a portion of the
small intestine be  inverted, and  then  suspended in per-
fectly transparent water, in a clear  glass, and examined
with a strong light, it  will appear like the external sur-
face of the skin of a peach, on which the down  or hair-
like processes are  not so close as those on velvet.  On
this surface, between the villi, there are many orifices of
mucous  follicles and of exhaling vessels.*  Exterior to
the villous  coat, many very small glandular bodies are
sometimes found, which are called after their describers
Glandulae Brunneri and Peyeri.
   The internal coat of the upper portion of the intestinal
tube is arranged  so as  to form a great number of trans-
verse  or circular folds or plaits, called Vahula Connu
ventes, which do not  generally extend round the intes-
tine,  but are segments of circles; they are so near each
other that their internal edges, which are very moveable,
may be laid upon  the  folds next to them, like  tiles or
shingles. It is  evident  that this arrangement of the in-
ternal coat  must add greatly to its length.  This coat is
extremely vascular, so  that in the dead subject it can be
uniformly coloured by a successful injection.  The minute
structure of  it has been the  subject  of very  diligent
inquiry.  There can be no doubt but that an immense

  * It appears clearly, from the account of Lieberkuhn, that the ori-
fices or terminations of the arteries on the intestines, are distinct from
the follicles; for he forced injection from the arteries  into the cavity
of the intestines, and found the follicles still filled with mucus. He
then urged the injecUon further, and filled the follicles, or forced
the mucus out of them. 
Lieberkuhn on the Villous Coat.
105
number of exhaling and of absorbent vessels open upon
it; but there  are many different opinions respecting the
termination of one set of vessels and the commencement
of the other.
   A very  interesting account  of the Villous Coat  was
published  in 1744,  by Lieberkuhn, who was consider.
ed by his cotemporaries as a most expert practical ana-
tomic, and was  also very  skilful in microscopical ex-
aminations, for which  he was particularly calculated, as
his natural powers  of vision were uncommonly strong.
In his essiy  he refers to his preparations, which were at
Berlin, and which appear to have excited great surprise
in the  minds of  the  members  of the   Academy of
Sciences of Prussia, at a time when  one of the first an-
atomists of Europe, the celebrated Meckel, was of their
 number.
   According to  this account, the internal surface of the
 small intestines  abound with villi, and with the orifices
 of follicles.  These villi are  about the fifth part  of a line
 in breadth. In each of them is a cavity filled with a soft
 spongy substance, which has one or more  orifices com-
 municating with the intestines, and from which also pro-
 ceeds  a lacteal vessel.  On  the  membrane which forms
 this  cavity, bloodvessels are most minutely  ramified.
 This cavity he  calls  an ampullula, and supposes  it to
 constitute the principal  part of the villus.  By injecting
 the arteries of the  intestine, he was able to pass a fluid
 through the ampullula into the cavity of the gut; he kept
 a stream of air in this way passing through  the ampullula
 until it was nearly dry and stiff, and then laid it open with
 a fine  instrument. From the appearances which then pre-
  sented, he inferred that the cavity of the ampullula was
  occupied with a spongy or cellular substance. Around
  each villus he found a number of mucous follicles, which
  often  were filled with  a tenacious mucus: and distinct
  from  these must be  the exhalent orifices, which dis-
    Vol. II.                O 
106         Hewson and others on the Villi.
charged a fluid injected by the arteries without passing
through the mucous follicles.
  Lieberkuhn died early, and left but one essay on this
subject, which was  originally published in Holland, in
1744, but has been republished by the Academy of Ber-
lin, in their Memoirs; and also by Mr. John Sheldon, of
London.
  This account of Lieberkuhn appears to have been ad-
mitted by Haller; but it has been rigidly scrutinized by
some of the anatomists of London, who were particularly
interested with the subject; as they had paid great atten-
tion to the absorbent system, and were very successful in
the investigation of it.
  The late Mr. Hewson, whose opinion is entitled to the
greatest respect, rejected the idea of the ampullula, and be-
lieved that the villi are composed of networks of lacteals,
as well as arteries and veins; although  he added  that
u this  is the only circumstance  concerning these  parts
in which he should differ from this very acute observer."*
  Mr.  Sheldon agrees with Lieberkuhn: but Mr. Cruik-
shanks asserts, that,  " in some hundred villi, he has seen
the lacteals originate by radiated branches, whose orifices
were distinct, on the surface  of the villus." The villus
being transparent, when the intestine was  immersed in
water,  these branches,  filled with chyle, could be seen
passing into  the lacteal. Mr. Cruikshanks therefore sup-
poses that Lieberkuhn was mistaken, and that the spongy
cavity, or ampullula,  was the common cellular membrane,
connecting together all the arteries, veins, nerves, and
lacteals.
   It seems probable, from Mr.  Cruikshanks' statement,
that Dr. William Hunter held the same opinion with him-
self. And there is also reason to believe that Monro the

    * See Hewson's Experimental  Inquiries, vol. 2, page 171. 
Fyfe and others on the Villi.
1P7
second, who studied  anatomy at Berlin,  held a different
opinion from Lieberkuhn.
   Mr. Fyfe, who has been much employed in the inves-
tigation of the absorbent system, and must be perfectly
acquainted with the preparations of  Monro, asserts that
each lacteal takes its rise upon one of the villi by numer-
ous short radiated branches, and each branch is furnished
with an orifice for imbibing chyle.
   Several of the late French writers adopt the opinion of
Lieberkuhn; but his countryman Soemmering  gives  a
different account of the subject. He says, that, besides the
bloodvessels, each villus consists of a fine network of ab-
sorbent vessels, whose orifices may be distinctly recog-
nized; and that from six to ten of these orifices are some-
times discovered.
   Mascagni, who has published the most extensive work
upon  the  absorbent system that  has yet appeared, sup-
poses Lieberkuhn to have been mistaken, and confirms the
description of Hewson: but he also agrees with Hewson
in his opinion of the general accuracy of Lieberkuhn.
   Notwithstanding their differences respecting the origin
of the lacteals, all these observers have agreed,  that the
orifices which communicate with the lacteals are on the
villi; and that these villi  contain also very fine  ramifica-
tions  of bloodvessels. They have also agreed,  that  the
surface of the intestine in  the intervals of the villi seems
occupied with the orifices of ducts  or of  exhalent  ves-
sels.*

 • On this subject the student will consult, with advantage, Hewson's
Experimental Inquiries, vol. 2d; Sheldon's history of the Absorbent
System, part 1st; Cruikshanks on the Anatomy of the Absorbing Ves-
sels; and the Historia Vasorum Lymphaticorum Corporis Humanij
of Mascagni. 
108
              Division of the Intestines.  •
  Although there is a considerable degree of uniformity
in the structure of  the intestinal canal, different parts of
it are very distinguishable from each other by their exte-
rior appearance, by their size, their investments, and their
position.
  The  first division  is into two great portions, which
are very different from each other in their diameter and
length, as well as their situation:  the first portion being
much smaller in diameter, and near four times the length
of the other.
  These  portion* are  therefore known by the names of
Great and Small Intestines, and the line of separation be-
tween them is very strongly marked; for they do not gra-
dually change into each other,  but  the alteration in size
and in exterior appearance is very abrupt,  and their  com-
munication  is not perfectly direct. A considerable portion
of the Great Intestine is fixed  immoveably in the abdo-
men, while a  large part of the Small Intestine is very
moveable.
   Each of these  great portions of  the intestinal tube is
subdivided into three parts. Thus, in the Small Intestine,
there is a piece at  the  commencement called Duodenum,
a great  part of which has no coat from the peritoneum,
and  is immoveably fixed  in  one situation; while all the
remainder of the smail intestine has a uniform covering
from the peritoneum, and is very  moveable.  This last
piece, notwithstanding its exterior  uniformity, is  consi-
dered as  forming  two  parts. The uppermost  two fifths
form one part, which is called Jejunum; and the remain-
der is called Ileon. The Great Intestine commences in
the lower part of the  right side of the abdomen, and
after proceeding up that side crosses over to the left, along
which it descends to the lower part again, when by a pe-
culiar flexure it proceeds  to the center of the posterior 
        Commencement of the Small Intestines.     109

margin of the pelvis, from which it passes down to the
anus. A short portion of this intestine, which is above its
junction with the ileon, is called  Cacum; the part which
proceeds from this, round the abdomen, is called Colon;
and the portion which is in the pelvis is called Rectum.


                Of the Small Intestines.
   Previous to the description of the small intestines, it is
necessary to observe, that the Mesocolon, or process of the
peritoneum connected to the transverse portion of the co-
lon,  forms a kind of moveable and incomplete septum,
which divides  the  abdomen into an  upper and lower
apartment. Above this septum are the stomach, with the
commencement of the duodenum, the liver, and the spleen;
below it, that portion of the small intestine which is called
jejunum and ileon, makes its appearance.  The portion  of
the intestine which passes from the stomach to the jeju-
num, and is called Duodenum, is so much involved by the
mesocolon, that the greatest part of it cannot be seen with-
out  dissecting the mesocolon from  its connection with the
back of the abdomen.  For the duodenum proceeds  back-
wards from the pylorus, and passing down behind the pe-
ritoneum, enters a vacant space between the two laminae
 of the mesocolon; it proceeds for some distance in this
 space, and then emerges on the lower side of the meso-
 colon. Here the duodenum  terminates, and the small in-
 testine then is invested by the peritoneum in such manner
 as to form mesentery, which continues  with it throughout
 its whole course to the great intestine. This portion of the
 intestine, although  very uniform  in its exterior appear-
 ance, as has been observed  before, is  divided into Jeju-
 num and Ileon: the Jejunum being the upper portion, which
 begins at the mesocolon; and the Ileon the lower portion,
 which opens into the great intestine. 
110           Situation of the Duodenum.
                  Of the Duodenum.
   The length of this  intestine is equal to the breadth of
twelve fingers, and hence its name.  It is very different
from the rest of the small intestine, not only as respects its
position, and investment by the peritoneum; but on ac-
count of its connexion with the liver and pancreas, by  ,
means of their excretory ducts, which open into it. From
this connexion with these  glands, probably, all the pecu-
liarities of its position  are to be deduced.
   When the stomach  is in its natural situation, the pylo-
rus is at some distance  from  the back of the  abdomen.
The duodenum proceeds backwards from this point, and
passes near the neck of the gall-bladder,  being here con-
nected with the small omentum; it then curves downwards,
and descends before the right kidney, sometimes as low as
the lower part of it; then it curves again, and passes over
to the left: after it has arrived at the left side of the spine, at
the second or third lumbar vertebra, it projects forwards
and downwards to form the jejunum. The only portion
of this intestine which is moveable, is that  which is in sight
as it proceeds immediately from  the duodenum, being
about an inch and a half, or two inches in length. The re-
mainder is connected to the back of the abdomen,  and lies
between the two laminae of the mesocolon. In its progress
it passes before the aorta and the vena cava, but the princi-
pal branch of the vena portarum is before it.
   The duodenum  is larger in diameter  than  any other
part of the  small intestines, and has a stronger muscular
coat. Its general situation admits of great  dilatation, and it
has been called  a  second stomach. Its  internal coat is
strictly villous, in the anatomical sense of the word; and
its folds, the valvulae conniventes, begin at a small distance
from the pylorus.  The orifices of many mucous ducts are
to be seen on its surface. It is supposed that some of these
are the terminations of ducts from  the glands of Brunner, 
Jejunum and Ileon.
Ill
which sometimes appear in the villous coat, or very close
to it exteriorly; being small flat bodies, with a depression
in the center, and a foramen in the depression.  They are
sometimes very numerous at the upper extremity of this
intestine, and diminish gradually towards the other extre-
mity.
   The  biliary  and  pancreatic ducts open posteriorly
into the duodenum, rather above  the middle of it.  The
orifice of  these ducts is generally  surrounded by a small
tubercle, which is oblong, somewhat rounded at one ex-
tremity, and pointed  at the other.  Sometimes this orifice
is in a plait,  like one of the valvulae conniventes. Most
commonly the two ducts unite before they perforate the
coat, so as to form but one orifice; and sometimes they
open separately, but  always very near to each other.
   Absorbent vessels, which contain chyle, are found  on
the duodenum.


                The  Jejunum and Ileon
   Are situated in  the abdomen very differently from the
duodenum.  When the cavity is opened, and the omentum
raised, they are in  full  view; and every portion of them,
except the two extremities and the parts  near them, can
readily be moved. This freedom of motion is owing to the
manner in which they are invested by the  peritoneum; or
in the technical language of anatomy, to the length of their
mesentery. They agree in their structure with the general
description of the small intestines, but their muscular coat
is rather weaker than that of the duodenum.  The valvulae
conniventes are very  numerous and large in the upper part
of the tube, or the jejunum; and  gradually diminish in
number, until they finally disappear, in the lower part of
the ileon.  The villous coat is in perfection  in the jejunum,
the villi being more  conspicuous  here than in any other
part of the  intestinal tube. There are frequently found, 
112     Distinction between Jejunum and Ileon.
exterior  to this  coat, but  intimately connected with it,
many small glandular bodies of a roundish form,  which
are often clustered  together  at that  part of the intestine
which corresponds with the interstice of the laminae of the
mesentery. They are called Peyer's glands, after the anato-
mist who first described them; and  are supposed,  like
the glands of Brunner,  to secrete mucus.  If a portion of
the jejunum be inverted, and moderately distended with
air, these bodies appear very  distinctly in it, dispersed at
small distances from each other.  In the ileon they appear
in small clusters, which often have  the  appearance of
disease.
   No natural line of separation for distinguishing the je-
junum and ileon from each other, is to be found; but these
names are still retained; and therefore a rule laid down by
Winslovv is generally adopted, viz. to name the first two
fifths of the tube jejunum, and the remainder ileon. There
are, however,  some important differences  between these
portions of the intestine.
   In the jejunum, the valvulae  conniventes are so nume-
rous, that they lie in contact with each other, as shingles on
the roof of a house;  in  the ileon they gradually diminish
in number, and  finally disappear. In the jejunum the villi
are much stronger than they  are in the  ileon.
   It is very difficult to  acquire a precise  idea of the ar-
rangement of this part of the  intestinal tube, while it is in
the abdomen, especially if it be much distended; but if it
be separated at  each extremity from  the intestine  with
which it is connected, and the mesentery cut off from the
back of the abdomen, and the whole then spread out upon
a flat surface, it will appear, as has been already said, that
the intestine is arranged so as to form a semicircle or large
curve; the concavity of which is opposite to the back of
the  abdomen, while  the convexity presents forward. It
will also appear, when  thus placed upon a table, that the
intestine, while connected with the mesentery, is laid into 
Construction of the Mesentery.         113
many folds. It has been supposed, that the middle portion
of the mesentery, and the intestine connected with it, is
generally in the umbilical region; and the two portions on
the sides of it are in the iliac regions:  but their situation
in the abdomen varies  considerably  at different  times.
When the viscera of the pelvis are empty, a large portion
of the small intestine is in the pelvis; but when those vis-
cera are filled, the intestine is in the general cavity of the
abdomen.


                   The Mesentery
   Is a process of the peritoneum, which is formed in the
manner of a plait or fold, and of course consists of two la-
minae. These laminae proceed from the back  part of the
abdomen, and are so near to each other, that they compose
one substantial process;  having cellular and adipose  sub-
stance, bloodvessels and neives, with absorbent or lacteal
vessels and their glands, between them.
   The form  of this process,  when  it is separated from
the back, and the intestines are detached from it, is some-
what semicircular:  that portion of its margin  or edge
which corresponds to the diameter of the semicircle, is
connected to the back of the abdomen, and called the root
of the mesentery; the edge, which is the circumference of
the semicircle, is connected with the intestine. The edge
connected with  the  back of the abdomen is commonly
about five or six  inches in length: the semicircular edgey
instead  of extending fifteen or eighteen inches, the ordi-
nary proportion, is attached to a portion of intestine some-
times twenty-four feet in length. The mesentery on ac-
count of this great  difference between its diameter and
circumference, has been compared to the ruffle of a shirt-
sleeve;  its roots being taken for the plaited edge of the
ruffle, and the circumference for its loose edge.  But the
comparison is not precisely accurate; for the mesentery is
   Vol. II.               P 
114            Root of the Mesentery.
not plaited at its root, but perfectly smooth, and free from
every kind of fold. It begins to enlarge towards its cir-
cumference,  and enlarges to that degree, that it falls into
plaits or folds: precisely such as would exist in a semicir-
cular piece of membrane about six inches in diameter, if
a number of simple incisions, of about an inch  and a half
in length, were made in a radiated direction from its cir-
cumference,  and if portions  like a sextant or quadrant
were taken from a circular membrane  three  inches  in
diameter, and united by their edges to these incisions, so
that their circumference might be continuous with the
circumference of  the large  semicircular piece.  In this
case, the portions like quadrants or sextants would as-
sume a folded position  like the edge of the mesentery,
while the middle of the semicircular piece would preserve
its regular form without folds; as is the case with  the me-
sentery at some distance within its circumferejjqp. By
many additions of this kind, the circujsnference «f a mem*
brane, which was originally a semicircle <of five or six
inches, may be extended so as to exceed greatly that of
the mesentery.  It seems of course/impossible to  form an
accurate model of the  mesentery with  a single  piece of
membrane or paper; but it may be easily made with clay,
or any ductile substance. A model of this kind must ne-
cessarily be folded after the manner of the mesentery; and
its circumference, like the mesentery, would appear as if
formed of portions of the circumference of smaller circles
united to each other.*
  The root of the mesentery commences with the jeju-
num on the lower  side of the mesocolon, at  the left of the
spine, and extends downwards near to the right  iliac re-
gion; crossing the spine  obliquely. When it is  examined

  * A model, upon the plan first mentioned, was invented by Dr. J.
G. Shippen. It  has been proposed, I believe by M. Gavard, to make
one with a single piece  of buckskin, of a semicircular form, by
stretching it at  the circumference. 
          Appearance of the Cacum and Colon.     115
in its natural situation, the peritoneum is found continued
from the back of the abdomen to the intestine; it then sur-
rounds the intestine, and continues from it to the back of
the abdomen again. There must therefore be two laminae
of peritoneum  in  the  mesentery,  and there must be a
small portion of intestine answering to the interstice be-
tween these  laminae, which is not covered by the perito-
neum.  The  bloodvessels, and absorbents'or lacteals, pass
most commodiously to  the intestines between these la-
minae; for they  are  connected  with large trunks that lie
on or near the spine, and the root of the mesentery com-
mences there.
   The glands  connected with the  lacteals or absorbents
are very conspicuous in the mesentery, and are commonly
called  mesenteric  glands. They are  of different sizes,
from more than half an inch to one or two lines in diame-
ter.  Th«y are  very numerous, and scattered irregularly,
but are seldom observed very near to the intestine. They
ar# often enlarged in consequence  of disease,  especially
in children*
   The nerves of the small intestines, which are derived
principally from the superior mesenteric plexus, are also
to be found  here.
   The adipose matter between the laminae of the mesen-
tery is very often in a  large quantity, but varies in pro-
portion to the general quantity of adeps in the  subject.
           OF THE GREAT INTESTINES.

                The Cacum and Colon
  Are very different from the small intestines in many re-
spects. They are much larger in diameter.  Their exter-
nal  surface is marked by three longitudinal  bands of a
light colour, which extend the greatest part of their length, 
116             Position of the Cacum.
and are placed nearly at equal distances from each other.
The spaces between these bands are marked by tranverse
indentations, which pass from one band to the other at
short but unequal  distances.  At these indentations the
coats of the intestine  are pressed inwards, as  if a fine
thread had  been drawn round it externally, while the
spaces between them are full and tumid, and on this ac-
count are called cells.
   The great intestine, with these appearances, begins, as
has been already observed, in the right iliac region, by a
rounded end which rests on the fossa or concave surface
formed by the costa of the ileum;  from this it is continued
upwards in  the right lumbar region, anterior to the kid-
ney, until it arrives near the liver, when it forms a curve,
and  passes directly across the abdomen to the left side.
In this course it approaches so near to the under side of
the liver, that it is often in contact with it, and  with the
gall-bladder, which, after death, tinges it with  a yellow
colour. On the left side it passes down the lumbar region,
before the kidney, to the left iliac  region; here it'is curved
so as to resemble the Roman letter S, inverted; this  curve
generally carries it to the right side of the spine, and then
brings it back to the center of the sacrum. Here the in-
testine  dianges its course, and  passing into the pelvis,
continues downward, in contact with the sacrum and coc-
cygis, and partaking of the curvature of those bones, until
it terminates at the anus, where  it is connected  with the
 sphincter and levator ani muscles.
   About two inches from the commencement of the great
 intestine the ileon opens into it laterally; and all that por-
 tion which is between its commencement and the insertion
 of the ileon is termed Cacum, or the blind intestine: that
 part of the great  tube,  which is included in its course
 from the insertion of the ileon to the posterior part of the
 brim of the pelvis, is called Colon; and the remainder,  or 
                Structure of the Colon.            117

the part which is contained in the pelvis, is termed Rec-
tum.
   The Cacum is nearly as wide  as it is long; it is fixed
in the right iliac fossa by the peritoneum, which invests
it so that the great body of the intestine projects from the
surface  of the fossa covered by the peritoneum;  but a
portion  is in close contact with the surface, and connect-
ed to it  by cellular membrane.  Its external surface, co-
vered by the peritoneum, is marked by two of the bands
or stripes before mentioned, which proceed on it length-
ways. These bands are in full  view, but the third band
is generally on  that part of the  intestine which rests on
the iliac fossa, and is therefore out of sight.  At the round-
ed extremity of the caecum, situated anteriorly and inter-
nally, is  a small process  resembling an earth-worm in
form and size: this is  therefore  called Appendicula Ver-
miformis. It is hollow, and communicates with the cavity
of the caecum at the place of junction; and like the caecum,
has its other extremity closed up. It is composed of the
same number of coats and has  the same structure as the
great intestine: its length varies  from two to four  inches.
   The  longitudinal bands above mentioned commence at
the junction of this appendix with the caecum, and conti-
nue throughout the extent of the colon.  They appear to
be formed by some of the longitudinal fibres of the  mus-
cular coat, which are arranged close to each other. These
fibres seem to be shorter than the coats of trie intestine,
and the interior coats adhere firmly to them. Thus are
 produced the indentations and cells; for if the bands are
 divided transversely, the indentations disappear, and the
 surface of the intestine becomes uniform.  One of these
 bands is covered by the mesocolon.
   The circular or transverse fibres of  the  muscular coat
 of the cacum and colon are very delicate, and not numer-
 ous.
   The internal coat  differs  materially  from  that of the 
 118               Valve of the Colon.

 small intestines, although at first view they seem to resem-
 ble each other; for if a portion of the ileon and of the
 colon be inverted and suspended in water, no villi can be
 seen with the naked eye on the internal coat of the colon,
 while those of the ileon are very visible.  The  glands ex-
 terior to this coat  are larger than those on  the small in-
 testines.
   Instead  of valvulae conniventes,  are the  ridges made
 by the indentations or depressions above described, which
 separate the  incomplete cells from each other.  These
 ridges  differ'essentially from the valvulae conniventes,
 because all the coats  of  the  intestine are  concerned in
 their  formation, whereas the valvulae  conniventes  are
 formed by the villous coat only; they also project into the
 cavity of the intestine, while the valvulae are laid on  its
 surface. They pass only from one longitudinal band to
 another, and, in consequence of this, the cells are small,
 and the position of each band is very evident  when the
 intestine is laid open.
   The communication of the ileon with the great intestine
 has been already stuted to be on the left  side of it, about
two inches from its commencement.  The aperture  is so
 constructed, that it is considered as a valve, and is called
the Valve of Bauhin,  or of Tulpius, after the anatomists
who have described it.  The appearance of the aperture is
 as follows:  If the caecum, with a small portion of the ileon
 and of the colon, be separated from  the other intestines,
 and kept in an inflated state until  it be so dry  as to pre-
 serve its form when opened, and then if the caecum and
 colon be laid open opposite to the aperture  of the ileon,
a large,  transverse ridge, resembling some of the ridges or
folds just described, will be seen projecting into the cavity
of the intestine. In the internal edge of this  fold is a  long
slit or opening, which forms the communication between
the two intestines. It  is obvious that the  form of this ibid
must be that of a crescent; and that its two  surfaces with 
          Structure of the Valve of the Colon.       119

the slit between them, must have the appearance of two
lips,  which would readily permit a fluid or  substance of
soft  consistence to pass from the ileon  into the  great in-
testines, but must impede, if not prevent, its passage back;
especially if the large intestines  were distended, as  then
the lips would be pressed against each other.
  When the peritoneal coat is dissected from each of the
intestines at their place of junction, and this structure is
then examined from without, it  appears as if a transverse
or half circular indentation had been formed by the villous
coat of the great intestine, and that the internal coat of the
extremity of the ileon  was  pressed into this indentation,
and  united to the internal coat of the great intestine which
formed it; while there  was a slit, both in the indentation
and in the end of the ileon, which formed a communica-
tion between the cavity of the great intestine and  the ileon.
The longitudinal fibres of both intestines, as well as  their
external coats, seemed to be united, so as to form a com-
mon cover for them; while the circular  fibres were blend-
ed in the two portions of the indentation which form the
lips of the orifice.
   This orifice is, of course, transverse with respect to the
intestine. It has been observed,  that there was a difference
in the thickness and strength of the two  lips or valves; that
the  lower valve was the strongest, and appeared to  have
the  largest proportion  of muscular fibres in its  composi-
tion. At the extremities of the orifice, and near each end
 of the fold  or  ridge, are  tendinous fibres, which give
 strength to the  structure; they  are called the Retinacula
 of Morgagni, as they  were first described by  that ana-
 tomist.
   There is great reason  for believing that this valve can-
 not prevent the retrograde motion of the contents of the
 intestines in all cases;  for in some instances of hernia and
 of colic, matter perfectly stercoraceous has been vomited,
 and the probable inference  from such a state of the eject- 
120
Position of the Rectum*
ed matter is, that this matter has been in the large intes-
tines. It is also said, that suppositories and enemata have
been discharged by vomiting.
  On the right and left sides of the abdomen, the colon is
in close contact with the posterior surface of the cavity.
The peritoneum, which covers this surface, extends over
the intestine also, and thus retail s it in its position. The
great arch of the  colon, which  is loose  and moves far
from the back  of  the abdomen, is invested by the two
laminae of the omentum,  which,  after  surrounding it,
unite again and form  mesocolon. Connected with the
exterior surface of the colon are many  processes, com-
posed of adipose membrane, varying in length from half
an inch to an inch and a half: these appear to  be of the na-
ture of the omentum, and are therefore generally deno-
minated Appendices Epiploica.

                     The Rectum.
   After forming the sigmoid flexure, the colon  termi-
nates; and the  rectum begins opposite to the lower sur-
face of the last lumbar vertebra, and nearly in  contact
with it: from this it proceeds downwards, forming a curve
like the sacrum, until it terminates at the anus, where it
is invested with the  muscles called the sphincter and le-
vator ani. It is called rectum, because in this course it
is supposed not to incline to either side; but it is often
found on one side of the middle line.*
   This intestine being in contact with the posterior sur-
face of the pelvis, is covered, on its anterior surface only,
by the peritoneum which lines the posterior surface of the
pelvis; and it is fixed in this situation by the peritoneum,
as the colon is on  the right and left sides of the abdomen,
but more loosely;  and therefore  the term Mesorectum has

   • Morgagni and Haller supposed it to be commonly on the left of
the middle line: Sabatier on the right. 
Structure of the Rectum.
121
sometimes been applied to that portion of the peritoneum
which is analogous to the mesentery and mesocolon. The
peritoneum does not extend to the end of the rectum;  for
it is reflected at the lower part of the pelvis from the rec-
tum to the bladder, or uterus, and does not line the bot-
tom of the pelvis; so that the lower part of this intestine,
as  well as of the other viscera of the pelvis, is below  the
peritoneum, and not  connected with it.
   The muscular coat of the rectum is much thicker and
stronger than that of any  other  intestine. The strata of
longitudinal and circular fibres which compose it are very
distinct from each other.  The longitudinal fibres are most
numerous, and terminate at the insertion of the fibres of
the levator ani muscle.  The  lower  circular fibres are in-
timately  connected with the sphincter ani.
   The internal coat is very vascular, but the villous struc-
ture is not apparent. Mucous follicles are  also very  nu-
merous;  and there are likewise some distinct glandular
bodies exterior  to this coat,  which vary in size in  dif-
ferent subjects.
   The quantity of mucus discharged from the rectum in
certain cases of disease, is sometimes  very great. The in-
ternal coat, in consequence of the contraction of the cir-
cular fibres exterior  to it, sometimes forms longitudinal
folds,  which have been  called its  columns;  these often
disappear when the  intestine is opened lengthways and
spread out. By the contraction of the  longitudinal fibres,
the internal coat is often thrown into folds or doublings,
that must assume a transverse or circular direction: they
occasionally pass down through the sphincter, and form
the prolapsus ani. The rectum is most plentifully suppli-
ed  with  bloodvessels, to be described hereafter;  and it
may be observed, that, on  the lower part of the internal
coat, the veins arc particularly numerous.
   The internal coat of the rectum terminates  abruptly
just within the anus, and is united to  a production of  the
  Vol.  II.               Q 
122      Absorbents and Nerves of the Intestines.

skin, which, like the covering of the lips, is very delicate
and vascular, and has an epithelium, or very thin cuticle,
spread over it.  The levator and sphincter ani muscles,
with which the termination of the rectum is invested,
are described in the first volume.
   The Absorbents of the Intestines are commonly deno-
minated Lacteals.  They originate on the internal surfaces
of these viscera, as has been already described. After
passing through the lymphatic glands, which are so nu-
merous on the mesentery,  they generally unite and form
one of the great trunks which compose the thoracic duct.
It is asserted,  that some of the absorbent vessels of the
lower intestines unite to the lymphatics of the loins.
   The Nerves of the Intestines are  principally derived
from the intercostals, or great sympathetics. From each
of these nerves, while they are in the thorax, an impor-
tant branch, called the ramus splanchnicus, arises.  These
splanchnic branches pass through the diaphragm, and are
the  chief  contributors to the ganglions  and  plexuses
formed in the abdomen.  A  plexus derived from this
source surrounds  the  superior mesenteric  artery, and
another the inferior mesenteric; and from these proceed
 the nerves of the intestines.


                     The  Omentum
   Requires a separate  description, although  several cir-
 cumstances  connected with its structure have been  al-
 ready noticed.  It often varies in its position; but when it
 is rendered  firm  by a quantity of adipose  matter, it is
 spread over  the intestines like an apron, extending from
 the lower edge, or great curvature of the stomach, towards
 the bottom of the abdomen.
   As has been already said, it is an extension of the  pe-
 ritoneum, in two laminae, from the concave surface of the
 liver to the lesser curvature of  the stomach;  and these 
      Origin and Arrangement of the Omentum.     123
laminae, after surrounding the stomach,  come in contact
with each other near  its great curvature. From this por-
tion of the stomach, from the commencement of the duo-
denum, and also from the spleen, the Omentum, composed
of two laminae, descends over the colon and the small in-
testines more or less low  into the abdomen;  it is then
folded backwards and upwards, and is continued until it
meets the great arch of the colon: here the  laminae  again
separate and inclose that portion of the  intestine, on the
posterior side of which they again approach each other,
and form a membrane like  the mesentery, of two laminae,
which passes from  the concave or posterior surface of the
colon to the back of the abdomen, where it is  continued
into the membrane which  lines that surface.  This last
portion is the Mesocolon: the portion between  the liver
and stomach is called the  Omentum of  Winslow, or the
lesser omentum; and the great portion  between the sto-
mach and  colon is called  the Great Omentum, or  the
omentum gastro colicum.  There is also a process  of pe-
ritoneum continued from that portion of the colon  which
is on the right side of the abdomen, and from the caecum,
which extends to some distance; it is formed of two la-
 minae,  that compose a cavity of an angular form. This
 has been called the Omentum Colicum.
   The great and small omentum, with a portion of the
 peritoneum on the back  of the abdomen, form  a sac,
 which incloses a distinct cavity in the abdomen.  The an-
 terior part of  this sac is composed  of  two laminae, and
 between these laminae are  the stomach and the great arch
 of the  colon.  This cavity, formed  by  the two omenta,
 communicates with the general cavity of the abdomen by
 a foramen  of  a  semicircular form,  which is behind the
 great cord of the vessels that go to the  liver.
   The omentum is  so delicate in structure, that, when
 free from fat, it is v?ry liable to laceration merely by ad-
 hering to the fingers, if they are dry. Winslow therefore 
 124   Varieties in the Appearance of the Omentum.
 advised that some unctuous substance  should be rubbed
 on the hands, before they were applied to it.
   The appearance of the great omentum is very different
 in different persons.  In the emaciated, it appears like a
 delicate transparent membrane; in the corpulent, it is like
 a broad mass  of  adeps, which sometimes is very thick.
 When it is thus loaded with adeps, it is most commonly
 spread over the small intestines: when  it is free from fat,
v it is often  compressed together, so as to form  a small
 mass near the arch of the colon, on the left side.
   The principal bloodvessels of the omentum are derived
 from those of the stomach, and are called gastro epiploic
 arteries and veins.
   The use of this membrane in the  animal economy has
 not been ascertained with  certainty. It  seems probable
 that one of its principal objects is to protect the small
 intestines,  and lessen the friction consequent upon their
 motion; but it has been supposed to answer several other
 important  purposes.*

   • See Halleri Elementa Physiologiae, vol. VI. pag: 381.
   Gavard. Traite de Splanchnologie, page 350.
   Dr. James Rush's Inquiry into the use of the Omentum. 
125
                   CHAPTER III.

     OF THE LIVER, THE PANCREAS, AND THE SPLEEN


                     SECTION I.

                    Of the Liver.

THIS largest viscus of the abdomen, when in a healthy
condition, is of a reddish brown colour. If it is taken out of
the subjf ct, and  laid on a flat surface, it is flat, but in the
abdomen it is convex and concave.
   It is situated in the right hypochondriac region, which it
occupies entirely; and extends through the upper portion
of the epigastric into the left hy pochondi iac region. Being
placed immediately under  the  diaphragm, and in close
contact with it,  as well as with the  inner  surface of the
right hypochondriac region, it partakes of their form, and
is convex above and concave  below. When thus situated,
it is of an irregular figure, between the circle and the oval,
but it is broader at the right extremity than at the left, and
very irregular in thickness.  The edge or margin which
is in contact with the posterior part of the right hypochon-
driac region, is very thick. It gradually becomes thinner
towards the left,  and also towards the front;  so that the
right margin, and a large portion of the posterior margin,
is very thick, while the  left and the anterior margin is
thin.
   The upper convex surface of the liver, when in its na-
tural situation,  is smooth:  the lower concave surface is
marked by several grooves  or fissures and eminences.
One of these, called the Umbilical or  the great fissure, 
126        Lobes and Fissures of the Liver.
commences at a notch in the anterior edge of the liver, to
the left of the middle, and continues to the posterior edge.
At the commencement of this fissure the umbilical liga-
ment enters; and at the termination, or near it, the vena
cava is situated. Opposite to this fissure, on the upper or
convex surface, is a ligament passing from the diaphragm
to the liver, which is called the falciform.  The fissure and
the ligament divide the liver into its two great lobes, the
Right and Left.
   Another great fissure, called the transverse or principal,
commences in the right lobe and extends to the left, cross-
ing the first mentioned fissure at right angles, and extend-
ing a very short distance beyond it.  It is very deep, and
rather nearer to the posterior than the anterior edge of the
liver. In this fissure, near to its right extremity, the great
vein,  called  vena portarum,  and the hepatic  artery enter,
and the excretory duct of the liver, commonly called the
hepatic duct, comes out. About the middle of the fissure
are two prominences, one on each side; these were called
the portae, or gates of the liver, and hence the  great vein
was called vena portarum. This vein has two very large
rectangular branches, which constitute what is called  the
sinus of the vena portarum, and they occupy  the principal
extent of the fissure.
   The liver is in close contact with the vena  cava behind;
and there  is either a  groove  in it for the passage of the
vein,  or this great  vessel is completely inclosed by it.
There is also an excavation on the lower surface of  the
liver, which is occupied by a portion of the  gall bladder.
   Besides the  great lobes above mentioned, there  are
also two or three prominent parts on the concave surface,
which are  denominated lobes. One of these, called Lobulus
Spigelii, is oblong, with two sides, and an angle continued
along its whole length,  which extends from the transverse
fissure to  the posterior margin of the liver.  It is situated 
Ligaments of the Liver.
127
between the posterior part of the transverse fissure, or
ductus venosus, and the vena cava.
  The anterior extremity of this lobe, which forms  one
of the margins of the transverse fissure, is somewhat bi-
furcated, and  has been called  lobulus  caudatus. The
largest portion of the bifurcated  end forms a process
like a papilla.
  Between the umbilical fissure and the depression for
the gall bladder is a protuberant space, which varies from
an inch and a quarter to two inches in breadth. This has
also been called a lobe, Lobulus Quartus or Anonymus.
  The peritoneum is extended from the surface  of the
abdomen to the surface of the  liver, in such manner as
to cover it, and to form ligaments,  which  have a great
effect in retaining it in  its proper situation. The whole
posterior edge of the liver is in contact with the back of
the abdomen.  The peritoneum  above the liver is reflect-
ed  to the upper surface of it, and the peritoneum below
it to the lower surface; so that two laminae of the  perito-
neum pass from the lower part of the diaphragm at the
back of the abdomen to the posterior edge of the liver.
These processes  of the  peritoneum are considered as
forming two ligaments, which are called the right and left
lateral ligaments. A portion of the posterior surface of
the liver, uncovered by the peritoneum, is  often in  con-
tact with a portion of the tendon of the diaphragm, also
 uncovered by peritoneum: around this place  of contact,
 the peritoneum is extended from the diaphragm to the
 liver,  and thus forms what has been called the coronary
 ligament of the liver.
    The peritoneum of the right side of the diaphragm,
 and of the abdominal muscles, as far down as the umbi-
 licus, is extended to the liver,  and joins it on the  con-
 vex  surface immediately opposite to the umbilical fis-
 sure.  The peritoneum from the left side of these  parts
 does the same; and as these reflections of the peritoneum 
128         Mode of supporting the liver.

are continued from so  low a part as the umbilicus, they
are extended not only to the convex surface of the liver,
but also to the great notch, and  along the umbilical
fissure.
   From the umbilicus proceeds a round cord-like liga-
ment, which in the foetal state was a vein, that passes to
the great fissure of the liver, and along it.  The process
of the peritoneum above mentioned is so connected with
this cord, that it incloses it in its  lower edge,  and the
whole is  called the falciform ligament  of the liver. The
cord,  when named  separately,  is  the umbilical or the
round ligament; and the membrane  or laminae of the pe-
ritoneum forms the suspensory ligament. Besides  these,
tht peritoneum on the lower side  of the liver is so ar-
ranged, that it not only extends to  the stomach, but to
the duodenum and the colon.
   By these  ligaments the position  of the liver must be
fixed to a great degree; and there is one additional con-
nection, which must have a  great effect in retaining it in
its proper situation. The vena cava  receives  two or three
great veins from the liver, at the place where it is in con-
tact with the posterior edge of that viscus; these veins of
course pass  directly from the substance of the liver into
the cava,  and connect it to that vessel. As the cava is
supported by  the heart, and also by  the diaphragm, it
must afford a considerable support to the liver.
   When the stomach and intestines are distended, they
must also contribute in a considerable degree to the sup-
port of the liver.
   The liver has a strong tendency, when we are  erect,
to change its situation; and some considerable support is
necessary  to counteract this tendency.  It would move to
the right,  when we lie on the right side, if it were  not in
contact with the ribs; and it  inclines to the left, for want
of such support, when we lie on the left side.
   It has been computed, that the liver descends about two 
     Acini of the IJver. Proper Coat of the Liver.  129

inches, when the position  of the subject is changed from
the horizontal to the erect. As it is  in contact with  the
diaphragm, it  is obvious that it must be influenced by the
motions of that muscle, and that it  must descend when
the diaphragm contracts.
   The liver is composed of a  substance which has some
firmness of consistence, although it is yielding; and is also
somewhat brittle or friable.* When  cut into, the sections
of many tubes, or vessels of different diameters, appear on
the cut surface. When the texture  of this substance is
more closely examined, it appears somewhat granulated,
or composed of very small bodies, which were called acini
by the anatomists who first described them. The whole
substance is  inclosed by the  peritoneum,  which is  ex-
tended to it  from the  surface  of the  abdomen in  the
manner that  has been already described. It has also  a
proper coat or capsule; and on the posterior edge, where
the laminae  of the lateral ligaments pass from  the dia-
phragm to the liver,  at some  distance from each other,
a portion of the liver, covered by this coat and by cellular
substance, is  in contact with  the diaphragm. The same
thing occurs likewise at the coronary ligament, f
   The liver holds the first place among the  glands of the
body for size,  but it is still more remarkable for some
other circumstances in its economy. In addition to an ar-
tery, which passes to it as arteries  do to other glands,
there is a large vein which also enters it as an artery; and
after  ramifying throughout the liver, communicates, as
does the artery, with  other veins, which carry the blood
from this gland  into the vena cava and the general circu-

   * It has been fractured in the living body by external violence.
   t Many anatomists deny the existence of this coat; but if one of the
laminae of the ligaments be carefully peeled off from the surface of a
liver which is slightly affected by putrefaction, it will be apparent,
although very thin. It was described by M. Laennec, in Le Journal
ilc "Medctine for 1803.
   Vol, II.                R 
 130      Vessels of the Liver. Hepatic Artery:

 lation. There are therefore three species of bloodvessels
 in the liver; and with  these  are found the vessels which
 carry out of the gland the fluid secreted by it, or the bile.
   The artery of the liver is denominated the Hepatic Ar-
 tery.  The vein which goes to the liver is called the Vena
 Portarum, from the place at which it enters. The veins
 which carry to the vena cava the blood brought to the li-
 ver by the hepatic artery and the. vena portarum, are called
 the Hepatic Veins; and  the*duct through  which the bile
 flows  out of the liver, is called the Hepatic Duct.  Three
 of these vessels, the Hepatic Artery, the Vena Portarum,
 and the Hepatic Duct, enter  the liver at die great fissure,
 at the spot where the prominences exist called the  portae;
 hence the name vena portarum was applied to the  vein.
   These  vessels ramify in  the  manner  presently to  be
 described; and it is ascertained by minute anatomical in-
 vestigation, that the liver is  entirely composed of the ra-
 mifications of these vessels and of the hepatic veins, with
 absorbent vesselsand nerves, which are connected together
 by cellular membrane.
   It has been already observed, that the first great branch
 sent off by the aorta in the abdomen, the Cceliac, divides
 into three branches, which go respectively to the stomach,
 the liver, and the spleen.
   The Hepatic is generally the largest of these branches.
 In its progress towards the liver it sends off  an artery to
the stomach, called the gastrica dextra. At the great fis-
 sure it divides into two branches: the right branch,  which
 supplies the right lobe of the liver, is of course the largest.
 This branch sends off one to the gall bladder, which is call-
ed the cystic artery; and also some  smaller  branches: it
passes under the hepatic duct, and ramifies  through the
 great  lobe of the liver. The left branch  is distributed
through the left lobe of the viscus. It  can  be proved by
 injection, that the hepatic artery communicates not  only
 with the hepatic veins, but with the  biliary duct, and the 
Vena Portarum.
131
 vena portarum also. It has been disputed whether the size
 of this artery is greater  than would be requisite  for the
 nourishment and animation of the liver.
    The Vena Portarum, the  great peculiarity of the liver,
 originates from all the chylopoietic viscera except the li-
 ver, and  is of course formed  by the union of the veins
 which  correspond  to all the  branches of the cceliac  and
 mesenteric arteries, as they are distributed to the stomach
 and intestines, the spleen, the pancreas, and the omentum.
 The veins from  the  intestines generally  form two great
 trunks, which are denominated the greater and lesser me-
 sentric veins.  The great mesentric  vein is situated to
 the right, and rather before the mesenteric artery. After
 it has approached  the origin  of the artery it  separates
 from it, and passes behind  the  pancreas: at this  place,
 nearly in  front of the spine, it is joined by the great vein
 of the  spleen, which forms almost a right angle with it,
 and these constitute the great trunk of the  vena portarum.
 The lesser mesenteric vein, which corresponds to the in-
 ferior mesenteric artery, and brings blood from the pelvis
 and from  the left part of the colon, becomes finally  a large
 vessel, and commonly unites with the splenic about an inch
 and a half before its junction with the superior mesenteric
 vein.  The vena portarum, thus formed, proceeds towards
 the liver,  inclining to the right,  and is generally about
 three inches in length:  in its course it sometimes receives
 small veins, which  in other cases pass to its splenic and
 mesenteric branches. When it has  arrived at the great
 transverse  sinus  of the  liver,  it  divides  into two large
 branches,  each of which forms nearly a right angle with
 it.  Their size is so great, that, when distended  with in-
jection, they appear like an independent vessel, into which
 the vena portarum  enters; and on this account they are
 called the  great Sinus of the vena portarum. They do not
adhere firmly to the glandular substance of the liver,  but
are united to it by cellular membrane. The right branch 
132          Hepatic Duct. Hepatic Veins.

is the widest and shortest.  It generally divides into three
branches; an anterior, a posterior, and a lateral branch;
which ramify minutely, and extend themselves in the right
lobe.  The left branch is much longer, and continues to the
extent of the great fissure. Near its termination it is join-
ed by the  umbilical ligament, which  has been  already
mentioned.  This branch is  generally in contact with a
branch of the hepatic artery and of the hepatic duct; and
ramifies, like the right branch, into the contiguous parts
of the liver.
  The Hepatic or excretory duct originates, by very small
vessels, from the acini or corpuscles of which the liver is
composed,  and  into  wfiich the minute ramifications of
the vena portarum and  hepatic artery extend. They ac-
company these  vessels,  increasing as they increase,  al-
though the  fluid they contain moves in an opposite direc-
tion;  and two large branches  which they ultimately form
are situated at the  portae  of the  liver, in contact with
the great branches  of the vena portarum and the hepatic
artery.
   These three vessels are in contact with each other be-
fore they enter the liver. The biliary duct is anterior, the
vena portarum  posterior, and the artery  to the left of
them. They are accompanied by nerves and  lymphatic
vessels, and are surrounded  by a considerable quantity
of cellular substance, and thus arranged are partially co-
vered with peritoneum.  The cellular substance  which
invests them continues with  them into  the liver,  and is
more particularly connected with the vena portarum. It
is called Glisson's Capsule, and was  supposed  to have
some contractile power, which assisted the circulation of
the vena portarum; but that idea is now altogether aban.
doned. The hepatic veins, which receive the blood of
the hepatic artery and the vena portarum, open into  the
anterior part of the vena cava, where it is in contact with
the  liver.  Generally  there are three of these veins, but 
          Nerves of the Liver. Lymphatics.        13S

sometimes there are only two; in which case one of them
is formed by two others, which unite immediately before
they open into the vena cava. It is to be observed,  that
the various  branches of these  veins do not accompany
those branches of the vena portarum or hepatic artery to
which they correspond,  but form very large angles with
them. This is probably owing merely to their termina-
tion in a part  so distant from that in which the artery
and the vena portarum  originate; but it is very different
from what occurs in  other glands.
   The Nerves of the Liver are derived from the  semilu-
nar ganglions of the splanchnic nerves. From these many
nerves proceed, which form a network denominated the
solar plexus. From this plexus many threads an' sent off,
which form a network  that is divided into the right .tnd
left hepatic plexus. These plexuses surround uV hepatic
artery and the  vena portarum, and  accompany them in
their ramifications throughout the liver, beii.g inclosed by
Glisson's capsule. They receive some threads from tiie
stomachic plexus, formed by the  par v^am. Although
the number of nervous fibres  is very considerable, their
bulk, compared with that of the liver, is very small.
   The Lymphatics of the Liver art extremely n imerous;
and those in that portion of the peritoneum which invests
the liver may  easily be rendered  conspicuous:  for by
pressure the injected fluid can be forced from the trunks
and large branches into the small ramifications, in oppo-
sition to the valves.  When all  the surface is injected in
this manner, it  has the colour  of the substance injected;
as is the case with parts which are very vascular, when
when the bloodvessels  are injected.
   The deep-seated  lymphatics are also  very  numerous
in the liver, and communicate freely with the superficial.
   The  superficial lymphatics which are on the upper
surface,  proceed through the diaphragm into the thorax
in their  course  to the  thoracic  duct. Those which are 
 134        Glandular Substance of the Liver.

 deep seated emerge from the liver at the portae, where
 the great vessels enter, and unite with the thoracic duct in
 the abdomen,  after passing through several glands. The
 lymphatics of the lower surface  unite with  the deep-
 seated.
   The glandular or  parenchymatous substance of the
 liver is of a reddish brown  colour, and moderately firm
 consistence. When it is cut into, the cut surface exhibits
 the sections of the branches of the different bloodvessels
 above-mentioned, and of the excrfrtoi^ ducts. These ves-
 sels are often distinguishable from' each other. The sec-
 tion of the biliary duct appears the, thickest; that of the
 artery next; the vena portarum is next in order; and, last
 of all, the venae hepaticae.          *
   The branches of the vena portarum are surrounded by
 cellular substance,  or Glisson's capsule; and therefore
 adhere less to the substance of the liver than the branches
 of the hepatic veins.  The sections of the hepatic ducts
 have  often bile in them,  and are  therefore termed pori
 biliarii. The branches of the artery are also very distin-
 guishable.
   When the internal substance of the liver is brought into
view, and examined accurately, it appears to  be formed
of small bodies, or acini, which are distinguishable from
each other.  If  the liver happens to be torn or lacerated,
the lacerated surfaces  are rough and irregular, owing to
the separation of these acini from each other.
   It is asserted by several microscopical observers, that a
minute  branch of each  of the aforesaid vessels can  be
traced into each of the acini. It is also declared, that if
each of these vessels be injected separately with mercury,
oil of turpentine coloured, or a saturated aqueous solution
of gutta gamba, there is no part of the glandular mass as
large as a grain of mustard seed in which these vessels
will not be found.
   Several anatomists of the first character have likewise 
Peculiarity of the Liver.            135
declared, that a fluid properly injected  into one of these
vessels, will  occasionally pass into all of them. Thus an
injection will not only pass from the vena portarum to the
biliary duct, but to the  hepatic artery and veins also.  It
will likewise pass, in a retrograde  course, from the biliary
ducts to the  vena portarum, and to the hepatic artery and
the hepatic veins; or from  any one of the four orders of
vessels into the three others.
   The great peculiarity of the liver is, that venous blood,
instead of arterial, is brought t$  it for the purpose of se-
cretion. Thus, the great vein of the chylopoietic viscera,
instead of passing to the  cava,  enters the liver by the
transverse fissure, and takes on the office of an artery; its
coats,  on this account, being much thicker and stronger
than those of the hepatic veins.*
   The Biliary or Hepatic Duct  is formed of very mi-
nute vessels, which originate in the acini above described;
these unite together like veins until they form considera-
ble branches, which finally compose the great ramifications
of the biliary duct.  This duct is very strong and firm, and
on  its  internal surface are the orifices of  many mucous
follicles or ducts.  It passes  from  the  transverse fissure
of the  liver,  with the hepatic artery, as before described,
and, at the distance of an inch and  a half or two inches
from the fissure,, it unites  with a duct from the gall blad-
der, which is called the  Cystic Duct. This duct is nearly
equal in length to the hepatic, and after running almost
parallel to it, at length unites so as to form an acute angle
with it. The cystic duct is smaller than the hepatic, and
they unite much like two branches of an artery.

  * A case is related by Mr. Abernethy, in the London Philosophical
Transactions, in which the vena portarum terminated in the vena cava
below the liver, without communicating with it. The hepatic artery
was the only vessel which carried blood to the organ, and was un-
usually large; the liver being nearly of the natural size. Some bilfc
v,r;is in the gajl  bladder, but it was less acrid than usual 
136
Gall Bladder.
    The Gall Bladder, from which the cystic duct arises, has
 the shape of  a pear, with a very long neck, curved in a
 way to be hereafter described. It is situated in a superficial
 pit or cavity in the concave surface of the right lobe of the
 liver; and its  fundus, or basis, often  projects a small dis-
 tance beyond the anterior edge of the viscus.  Its position
 is such, that  it extends from before backwards, and in-
 clines rather  to the left; of course, therefore, when  the
 subject lies on his back, the bottom of the bladder is the
 uppermost part of it; when he lies on the left side, it is
 also higher than the neck; and  when he lies on the right
 side, it is the lowermost.
   The gall bladder consists of  an internal coat,  and one
 that is cellular or nervous, and has somewhat of a fibrous
 appearance. This coat  connects the  gall bladder  to the
 surface of the pit or cavity in which it lies. The perito-
 neal coat of the liver is extended from the surface  of the
 viscus  over that part of the surface of  the gall bladder
 which is not in contact with it.
   The internal coat has a peculiar structure, with a faint
 resemblance to that of the villous membrane.  It is  so ar-
 ranged as to  form very fine  folds, which have various
 directions: in  some places they make a network; in others,
 as the neck of the bladder, they are longitudinal. Many
 mucous follicles exist on its internal surface.
   The neck of the gall bladder is suddenly bent down or
 curved upon itself, and twisted, so that it resembles the
 neck of the swan, when the head of that bird is applied to
 one side of its breast.
   A branch of the hepatic artery,  which leaves it before
 it enters the liver, is appropriated to the gall bladder, and
 is  therefore denominated the cystic artery.  The  veins
 corresponding  to this artery empty themselves into the vena
portarum.* The  lymphatic vessels are united  to  those
  * It has been justly observed by John Bell, that the veins would
 not terminate thus, if bile were secreted by the gall bladder. 
       Ductus Communis Choledockus. The Bile.    137

which are  found on  the lower  surface of the liver, and
the nerves are derived from the  hepatic plexus.
  The gall bladder appears to be merely a reservoir, into
which bile passes through its duct in a retrograde direc-
tion.  If air be blown  through the hepatic duct from the
liver, it will pass to the gall bladder almost as freely as it
passes to the duodenum.
  The biliary duct from the liver, after receiving the duct
from  the gall bladder, takes the name of Ductus  Com-
munis Chotedochus. It is wider than either of the other
duets, and near three inches in length.  It passes down
before the vena portarum, and on the right of the hepatic
artery, to  the posterior surface  of the right extremity of
the pancreas. It passes  through a small  portion of that
gland, and  then perforates the muscular coat of the duo
denum; after  which it proceeds from half an inch  to an
inch between this coat and the villous, and opens into the
cavity of the intestine. The orifice forms a tubercle which
extends lengthways of the intestine, and is rounded above
and pointed  below, with a slit  in it. While this duct is
in contact with  the  pancreas,  a  duct from  that gland
generally opens into it, so that the biliary and  pancreatic
fluids enter the duodenum by the same orifice;  but some-
times the pancreatic duct opens into the duodenum by a
distinct orifice, very near to that of the biliary duct.

    The Bile, or fluid secreted  by  the liver, appears to answer
      a two-fold purpose in the animal economy.  It produces
      a chemical effect upon the  alimentary mixture which
      passes from the  stomach through the intestines; and it
      increases the  peristaltic motion of  those  important
      organs.
        By an inverted action of the duodenum, some of this
      fluid is frequently carried upwards into the stomach: it
      then  often produces only slight derangement of the
      functions and sensations connected with that viscus; but
      sometimes  violent vertigo, and even convulsions,  seem
  Vol. IT.               S 
138                      The Bile.
to have arisen merely from the presence of a large quanti-
ty of bile in the stomach; for they have gone off com-
pletely upon the discharge of bile by vomiting.
   Notwithstanding these effects of bile in certain cases,
in which a great deal of it exists in the stomach,  it is
often carried into the mass of  blood in large quantities,
and appears to be mixed with  the  serum, and to circu-
late through the body, without producing any very sen-
sible  effect: thus many persons who  are  deeply tinged
by  bile in their blood, experience but few effects  that
can be imputed to the mixture of it with the circulating
fluids; and neither the brain nor the heart appear to be
much influenced by the circumstance.
   Bile is miscible with water and with alcohol, and  also
with  oily substances; and it often assumes a green co-
lour, when mixed with  acids.  The colour of the alvine
discharges is derived from the bile, and they are there-
fore sometimes very green, when  the acetous fermen-
tation takes place  in the contents of the stomach and
bowels.
   It  is asserted  by some chemists,  that ten  parts in
ele\en  of  the human bile consist of water;  that albu-
minous matter composes about one  forty-sixth part of
it; and  that there is nearly  an equal  quantity of resin-
ous  matter in it. There is  also a small quantity  (one
part  in 244) of uncombined soda dissolved in it, and a
smaller  quantity of neutral  salts, consisting of soda
combined  with the phosphoric, sulphuric and  muriatic
acids.  In addition to these  there  is a very small quan-
tity of phosphate  of lime and of oxide of iron, and some
yellow insoluble matter.
   The bile in the  Gall Bladder is generally more  vis-
cid than that which is found in the Hepatic Duct. 
The Pancreas.
139
                    SECTION II.

                   Of the Pancreas.
  THE pancreas is a glandular body, which has a strong
resemblance to the salivary glands in several particulars.
It is nearly six inches in length, and  is irregularly oblong
in its form,  one extremity being much larger than  the
other. Its large extremity is in contact with the duodenum,
and it extends from this intestine in a transverse direc-
tion to the spleen, to which it is connected by the omen-
tum and  by bloodvessels.  Ii is not invested by the peri-
toneum, but is situated in the space which exists between
the two lamina; of the mesocolon, as they proceed from
the back  of the abdomen, before they come  in contact
with each other. It  is anterior to the aorta and vena cava,
and to the mesenteric vein, or main  branch of the vena
portarum; being connected to these parts by cellular mem-
brane.  At the right extremity, which  is connected with
the duodenum, is a process of the gland that extends
downwards  in close contact with the  intestine. This is
called the head of the pancreas, or the lesser pancreas.
  The position of the pancreas is such, that one of its sur-
faces looks forwards and  rather  upwards, and the other
backwards and downwards; one edge is of course poste-
rior and superior, and the other  anterior and inferior. The
posterior of these edges is much thicker than the other,
and has a groove or excavation  which is occupied by the
splenic bloodvessels.
  This gland differs from  the other  large glands of  the
abdomen, inasmuch as it has not a  large artery particu-
larly appropriited to it;  but instead  of this,  it receives
branches from the contiguous arteries.
  The arterial blood of this gland is partly supplied by
the splenic artery,  which,  in its  course from  the main 
14 J
Pancreatic Duct.
trunk of the coeliac to the spleen, while it is in the groove
at the edge of the pancreas, sends off into the gland one
considerable branch called the great pancreatic,  and a
number of small  branches, which  go off in  succession.
In addition to  these, the pancreas  receives vessels from
one of the branches of the hepatic  artery, before it sends
off its great ramifications, as well as small twigs from se-
veral  other contiguous arteries.  The veins  correspond
with the arteries,  but ultimately are discharged into the
vena portarum.
  The pancreas resembles  the salivary glands in colour,
and also in texture; for  it is of a dull white colour with a
tinge of red, and it appears to consist of small bodies  of a
granulated form,  which are so arranged as  to compose
small masses or lobes that are united to each other by cel-
lular membrane. Each of these granulated bodies receives
one or more small arterial twigs, and from it proceeds not
only a vein but a small excretory duct, which uniting with
similar  ducts from the  adjoining granulated  portions or
acini, forms a larger duct in each lobe or mass; these open
into the great duct of the gland, which proceeds through
it lengthwise from the  left extremity, in which it com-
mences,  to the  right.
  This  duct is situated in  the  body of the gland, which
must  be dissected to bring it into  view. It is  thin and
transparent, like the ducts of the  salivary glands, and is
rather larger in diameter than a crow's quill. In its  pro-
gress towards the right extremity of the gland it gradually
enlarges, and commonly receives a branch from the  part
called the lesser pancreas. It most  commonly unites with
the biliary duct before it opens into the duodenum: some-
times these ducts open separately, but very near to each
other. They penetrate  the coats  of the intestine rather
obliquely, and between  four and five inches from the py-
lorus. This canal is sometimes  called  Ductus Wirsun^i,
after an anatomist who published a plate of it. 
Size of the Spleen.               141
  The  pancreas  has an irregular  surface, and no coat
which covers it uniformly. It is invested by cellular mem-
brane,  which also connects  its different lobes to each
other. Absorbent vessels and nerves are traced into it.
  The portion called the lesser pancreas adheres to the
duodenum, and when  it is enlarged by disease, the pas-
sage of aliment through that intestine is much impeded,
and sometimes completely obstructed.*
  It is now generally believed that the fluid secreted  by
the pancreas  is similar to that which is produced by the
salivary glands.
                     SECTION III.

                    Of the Spleen.
   THE Spleen is a flat body of a blueish colour, and an
irregular oblong form, with thick edges, which are indent-
ed in some places.
  It is various,  in  different  subjects, both in size and
form.  Its most  common size is between  four and five
inches in length, and about three or four inches in breadth;
but it has often been found of more than four times this
size; and  it has also been  seen not much longer than*an
inch.  Its ordinary weight is between six and nine ounces;
but it has  varied in different subjects from eleven  pounds
to one ounce. It is supposed,  by many physiologists, that
it frequently  varies in size in  the same individual.
   It is situated  in the left hypochondriac region,  in con-

  • In several cases where examination after death evinced that the
pancreas had become enlarged and indurated, particularly at the right
extremity, the principal symptoms were jaundice; great uneasiness
after taking food; vomiting some time after eating, bnt not immediately;
extreme acidity of the matter rejected. 
142          Enlargement of the Spleen.

tact with the diaphragm, below the eighth rib. The posi-
tion of the spleen is somewhat oblique,—one extremity
being directed  downwards and rather forwards, and the
other upwards and backwards; but when the stomach is
distended, the lower end of it is pushed  forward by the
great extremity of that viscus.
  In general it is so deeply seated in the left hypochon-
driac region, that it is out  of view  when the subject is
opened in the ordinary way: but  in some cases of enlarg-
ment, after the intermitting fever, it has extended  down-
wards, nearly as low as the pelvis; and  towards the right
side, beyond the umbilicus.
  The external surface of the spleen is convex, in confor-
mity to the surface of the diaphragm, with which it is in
contact. The internal surface of  the spleen is irregularly
concave, having a longitudinal  fissure which  divides it
into two portions.
  The spleen is invested by the peritoneum, one process
of which is often extended from the diaphragm, above
and behind it, in the form of ligament. Another process
of the same membrane is extended  to it from the great
extremity of  the stomach.  The peritoneum  is also con-
tinued from the spleen in the form of omentum.
  Within this peritoneal covering is the proper coat of
the spleen, which is so closely connected to it, that many
anatomists have considered them as one membrane: they
are, however, very distinct at the great fissure, but the
external coat is extremely thin.
  The proper coat of the spleen is not very thick; it is
dense and firm, and somewhat elastic, but not much so. It
is partly transparent.
  The spleen has a large artery,  which is one of the three
great branches of the cceliac. This vessel runs in an undu-
lating manner in a groove in the upper edge of the pan-
creas, and in this course sends off many small branches
 to supply that gland. The splenic artery, before it arrives 
Vessels of the Spleen.              143
at the spleen, divides into five or six branches, which are
also undulating in their progress, and penetrate into the
body of the viscus at the above-mentioned fissure. These
branches are distributed to every part of the viscus, and
ramify minutely.
   From these branches, or from the main trunk before it
ramifies, three or four smaller branches proceed to the left
extremity of the stomach. They are called vasa brevia or
arterias breves.
   The arteries which enter  the spleen  are accompanied
by veins that emerge from it,  and unite to form a great
trunk. This trunk observes a course corresponding to that
of the splenic artery, and receives veins from the stomach
and pancreas, which correspond with the arterial branches
sent to those organs. The splenic vein is one of the prin-
cipal branches of the vena portarum.
   The splenic artery is  very large  in proportion to  the
viscus to which it is sent, and the vein is unusually large
in proportion to the artery.  The vein is also very tender
and delicate in its structure.
   The absorbent vessels of the spleen are  very numer-
ous. It has been asserted, that when those of the external
coat  of the  spleen are injected,  they  are  sufficient  to
form a fine network on it.  The absorbents of the deep-
seated parts unite to the superficial  at  the fissure where
the  bloodvessels enter. They terminate in the thoracic
duct, after passing through  several lymphatic glands.
   The nerves of the spleen are derived from the solar
 plexus:  they form  a plexus round  the vessels, and  ac-
 company them through the  viscus.
   The spleen consists of  a  substance which  is  much
 softer than that  of any other  viscus  of the abdomen.
 This substance is made up  either wholly or in great part
of the ramifications of the splenic artery and vein, which
are  demonstrated by injections to be  very  minute  and
numerous in this body. There  are also many fine white 
 144     Malpighi on the Structure of the Spleen.

 cords,  like threads, which pass from the internal surface
 of the  inner coat  of the spleen into its soft substance, in
 which  some  of them ramify. These cords connect  the
 substance of the spleen pretty firmly to its coat,  and they
 seem to have the effect of rendering the exterior part of
 the  substance more firm and dense than  the  internal.
 They are particularly conspicuous if the  spleen be im-
 mersed in water, and the coat pulled off while it is in that
 situation.
   The  spleen has a strong resemblance to the glandular
 organs,  but has no excretory duct, and its particular
 function is not very obvious:  for these reasons the struc-
 ture of this organ is a subject of very interesting inquiry.
   Malpighi, who  took the lead in researches of this na-
 ture, before injections of the bloodvessels  with wax were
 in use,  after investigating  the structure  of the spleen by
 long maceration, by boiling, by inflation, by the injection
 of ink  or coloured fluids,  and by examination with mi-
 croscopes, declared that its  structure was cellular; that
 the cells communicated more freely with  the veins than
the arteries; and that they might be considered as appen-
dices of the veins. He also asserted, that a large number
of white bodies or vesicles were to be found in those
cells, and throughout the whole substance of the spleen,
which were in bunches like grapes, and preserved  their
whitish colour although the  vessels around  them  were
injected with a coloured fluid. This  description  of  Mal-
pighi appears to have been admitted by some of  the very
respectable anatomists who were cotemporary with him;
but it was most zealously  opposed by Ruysch, who ex-
hibited  the spleen  so  completely injected with wax, that
it appeared to be composed entirely  of vessels.*

  * Two plates, taken from drawings of these preparations, are pub-
lished in  Ruysch's works. One is attached to Epistola Problematica
Quarta, in the second volume; and the other to Thesaurus Septimus,
in the third volume. 
             De La Sone on the Spleen.           145
  Ruyscn appears to have paid great attention to this
subject, and to have made  many  preparations  of the
spleen. From these he derived the opinion, that the sub-
stance of this organ was entirely composed of arteries,
veins,  absorbent vessels and  nerves; and  that if it were
properly injected before it was dissected, no other struc-
ture would be found.  He stated, that the minute  ramifi-
cations of the bloodvessels appeared to have acquired a
peculiar quality, and were so  soft and delicate, that their
texture was destroyed by the least friction; and that by
the slightest degree of putrefaction they appeared to be
reduced to a fluid state. He also denied the existence of
cells, or of the whitish bodies described by Malpighi.
  The question thus at issue between these great masters
of their art, was very carefully examined  by M.  De La
Sone,  a French physician, whose observations are pub-
lished  in the Memoirs of the Academy of Sciences for
1754.  After repeating the processes  of  each of these
anatomists,  and instituting some others in addition, he
adopted the opinion that there was in the texture of the
spleen a pulpy  substance which was not a mere coagu-
lum, but which, however, could not be injected.
  He  derived his opinion from this fact among  others.
After macerating the spleen a considerable time, and in-
jecting water into the vessels  until it returned colourless,
he injected ink, and confined it some time in the vessels
by tying them:  he then allowed  the ink to flow  out of the
vessels, and made various sections of the  spleen, but no
ink appeared in the pulpy substance, although it was
visible in many small vessels  which ramified in that sub-
stance. He observes that  this could not have been the
case, if the pulpy substance had been composed entirely
of vessels, as was supposed by Ruysch.
  He also examined the spleen  after it had been injected
with wax, according to the manner  of Ruysch,  and be-
lieved  not only that the pulpy matter remained uninject-
  Vol. II.               T 
146 Haller and the French Anatomists on the Spleen.
ed, but that Ruysch himself,  in his own preparations,
removed this  substance,  supposing it to  exist for the
mere purpose  of connecting the vessels to each other.
   To see the bloodvessels in the same state of distention
in which they  were during life, he tied the splenic ves-
sels in a living animal,  and removed the spleen with the
ligatures on the vessels.  In this situation  he  boiled it,
and then examined the appearance of the vessels and the
pulpy  substance. From these, as well as his other obser-
vations, he decided, that the  pulpy substance did not
consist entirely of vessels, but was an additional and dif-
ferent  structure.
   He also  suggested, that as the brain and the muscular
fibres  were so covered by bloodvessels  in the injected
preparations of Ruysch,  that  they appeared to be  com-
posed  entirely of vessels, when  in fact  they  consisted
of a different  substance,  so  the pulpy substance of the
spleen was covered  or obscured  by the  bloodvessels
which  passed  through it, without constituting its whole
substance.
   He  confirms the account of Malpighi  respecting the
Whitish Vesicles or Follicles; and  states,  that in a ma-
jority of cases they are not to be  discovered  without  a
particular preparation; but that they are generally  made
obvious by long  maceration of the spleen in  water. In
his opinion they are the most essential part of the organ.
   Notwithstanding these  investigations  of  M. De  La
Sone, the question respecting the structure of the spleen
remains not completely decided even to this day.
   Haller, who was perfectly well acquainted with the sub-
ject, inclined  to  the  opinion of Ruysch; while Sabatier
adopted completely the opinion of De La Sone.
   It appears from the statement of Gavard, that Desault
did not admit the existence of the transparent bodies; al-
though he believed that the pulpy substance of the spleen 
British Anatomists on the Spleen.
147
consisted of cells which resembled those of the cavernous
bodies of the penis.
  Boyer, whose descriptions of the animal structure ap-
pear to have been formed with scrupulous  exactitude,
admits the  existence of transparent bodies;  sometimes so
small as to  be scarcely visible, and sometimes as large as
the head of a pin. He observes, that the best method of
examining  them is to place a very thin slice of the spleen
between the eye and a strong light, when the  transpa-
rency of these bodies occasions the slice of the spleen to
appear as if perforated.
   As to the general structure of the pulpy  substance, he
avows himself unable to decide respecting  it;  but ob-
serves, that upon examining the cut surface of the spleen,
you perceive black liquid blood flow from the vessel-*;  if
you then, scrape this surface, you  may express easily a
species of sanies different from that which flows from the
vessels, which, after exposure, becomes red,  and resem-
bles coagulated blood:  whether this is contained in the
capillary vessels, or in the cavities  of  this organ, he ac-
knowledges himself unable to determine.
   Notwithstanding the sentiments of these French gen-
tlemen, many of the British Anatomists, who are entitled
to  great attention on account of their skill in minute in-
jections, have adopted the ideas of Ruysch. Among these
 are to be mentioned the late Dr. F. Nicholls, and many
 of the anatomists of London, as well as the second Pro-
 fessor Monro, of  Edinburgh. There are, however, two
 remarkable exceptions to this account of the British Ana-
 tomists. The late Mr. Falconar, who wrote a dissertation
 on the situation and structure of the spleen, which con-
 tains the sentiments of the late truly respectable Mr. Hew-
 son,* after stating diat the organ was extremely vascular,
 so that when injected it appeared like a mere  congeries of
* See Experimental Inquiries, vqJ, III. 
148             Questions relating to the
vessels, makes this unequivocal assertion,—that there are
innumerable cells dispersed  throughout the whole sub-
stance of it, which are so small that they are only to be
discovered by the aid of a microscope; and are to be seen
after steeping a  thin piece of spleen, the bloodvessels of
which have been minutely injected, in clear water during
a day, and changing the water frequently. He also adds,
that the ultimate branches of the arteries and veins form
a beautiful network on each  cell; and that these cells are
sufficiently distinguished from the  irregular interstices of
die cellular  substance, by their round figure  and their
great regularity.
   Mr. Everard  Home, in his papers on the  structure and
uses of the spleen, confirms the account of the vesicles in
this organ; and  adds, that these vesicles are occasionally
seen in a distended and in a contracted state. That when
distended they are twice as large as when contracted, and
are distinguishable by the naked eye; whereas, when con-
tracted, they require a magnifying glass to be distinctly
seen. These observations appear to have been made upon
quadrupeds.*
   Professor Soemmering appears to unite in the general
sentiment of the British anatomists, that the spleen is sim-
ply vascular. He says, that the tuberculi which sometimes
appear in it, when examined with a magnifying glass, ap-
pear to be composed entirely of vessels.
   There are therefore  two questions not perfectly decid-
ed respecting the spleen.
   First. Whether its general structure is simply vascular,
or whether there is any other structure, either cellular or
more substantial, which composes  its general bulk.
   Second. Whether the  small transparent vesicles, ori-
ginally described by Malpighi, are to be  regarded as es-
sential parts of the structure  of the spleen.

      •See the London Philosophical Transactions for 1808. 
Structure of the Spleen.            149
  With  respect to  the  first question,  the  injections of
Ruysch,  and of the  British Anatomists in general,  and
even of Mr. Hewson, as well as of Haller and Soemmer-
ing, seem to afford positive facts in opposition to those of
a negative kind adduced by M. De La  Sone, and render
it highly probable that the general structure is simply
vascular.
  But the second question  stands on different grounds.
The existence of small transparent vesicles,  although de-
nied by Ruysch, and neglected by the British Anatomists
in general, was asserted as a positive fact by Malpighi and
De La Sone; and their assertions have  been confirmed,
not only  by most of the French Anatomists, but also by
Hewson  and Home among the British.
  The sentiments of physiologists respecting  the func-
tions of tj^e  spleen,  are  more discordant than  those of
anatomists respecting its structure; although the subject
has been considered by many authors of great ingenuity.*

        *See M. Lieutaud. Elementa Physiologic
         Hewson's Experimental Inquires, vol. III.
         Dr. Rush. Medical Museum, vol. III.
         Haller. Elementa Physiologic, torn.  vi. pag. 414. 
150
                    CHAPTER IV.

  OF THE URINARY ORGANS, AND THE GLANDULE RENALES.

THE urinary organs consist of the Kidneys, which are
situated in the lumbar regions; of the Bladder, which is in
the pelvis; of the Ureters, which are flexible tubes or ca-
nals that pass from the kidneys to the bladder; and of the
Urethra, or  tube through which the urine is discharged
from the bladder.
   These organs have but little connexion with the peri-
toneum.  The kidneys are behind it;  and a considerable
quantity of cellular membrane is placed between-them and
it. The ureters are also behind it; and but a part ©f the
bladder is invested with it.
   The  Glandula Renales are described with the urinary
organs, on account of their contiguity to the kidneys; and
to avoid a derangement of  the natural order of descrip-
tion they are considered first.
   The urethra pertains to the organs of generation as well
as to the urinary organs, and can be  described most ad-
vantageously with them.
                     SECTION I.

               Of the Glandula Renales.
  THESE are two small bodies,  situated on the psoas
muscle, one on each side of the spine, behind the peri-
toneum and above the kidney, being in contact with its
upper  and anterior edge. They  have an  irregular  se- 
Glandula Renales.              151
milunar figure with three sides, one of which is accom-
modated to the convexity of the kidney. Their colour is
commonly a dull yellow.
   The appearance and texture of these bodies have some
resemblance to those of glands, and hence their  name;
but they have no excretory duct.
   When they are laid open by an incision, a cavity often
appears,  which is somewhat  triangular, and from   the
lower part of it a small thin ridge arises.*
   A small quantity of fluid is generally found in it, which
has a very dark colour in adults, is yellowish in  young
subjects, and  red in infants.
   These bodies have not a single artery appropriated to
them, as the spleen has, but receive small branches from
several contiguous sources; viz. from the arteries  of the
diaphragm, from the cceliac artery or the aorta, and from
the arteries of the kidneys. There is generally one prin-
cipal vein, as  well as some that are smaller, belonging to
each of these  bodies: the large vein on the right side ge-
nerally opens  into the vena cava, and  on the left into the
left emulgent vein.
   These bodies were first described by  Eustachius, and
have been  regarded with attention by many anatomists
since that  period. They exist in a  great number  of ani-
mals; but their nature and functions are  altogether un-
known.

   * The cavity  in these bodies has sometimes been sought for in
 vain. Haller found it in sixteen cases out of nineteen. 
152
                    SECTION II.

             Of the Kidneys and Ureters.
  THE kidneys are two glandular bodies which secrete
the urine. They are of a dull red colour, and their from
has a strong resemblance to that of the bean which bears
their name.  They have a peculiar texture, which is uni-
form, and not granulated or composed of acini; and they
are covered by a thin delicate tunic, which has no con-
nection with the peritoneum.
  They are  situated in the lumbar regions of the abdo-
men, one on each side of the spine. They are  opposite to
the two last dorsal and the two first lumbar vertebrae.
They rest principally upon the psoas and the quadratus
lumborum muscles, and their position  is  oblique;  the
concave edge presenting inwards and forwards, the .con-
vex edge backwards, and the upper extremity approach-
ing nearer to the spine than the lower.
  The Right Kidney is situated  rather  lower than  the
left:  it is below  the posterior part of the right  lobe of the
liver, and behind the duodenum and the colon. The Left
Kidney is below the spleen,  and behind the descending
portion of the colon? Each  of the kidneys is below and
very near to one of the glandular renales.
  They are  surrounded with a large quantity  of lax adi-
pose membrane, which in corpulent persons forms a very
large mass of adeps  around them; while in the emaciated
they are surrounded with a membrane almost free from
fat. Each kidney has two broad  sides,  two extremities,
and two edges. The side or surface which is posterior,
when the kidney is in its  natural situation, is rather
broader than the other. The upper extremity, or portion,
is also broader and  larger than  the lower.  The edge
which is posterior and  external is regularly convex;  the 
The Kidneys,                 153
anterior edge is concave; but the concave edge, or mar-
gin,  is not very regular. In the middle it is  largely in-
dented; in this  indentation is a deep fissure, which sepa-
rates  the two broad surfaces or sides of the gland from
each  other; and here the breadth of the posterior surface
is evidently greater than the anterior.
   Each of the kidneys receives  a large  artery,  which
proceeds immediately from the aorta, nearly  in a rectan-
gular direction. A vein, which opens into the vena cava,
accompanies  the artery. It is obvious, from the situation
of the kidneys with respect to the great vessels, that the
artery on the right side must be longer than that  on the
left,  and that  the reverse of this must be the case with
the veins: the veins  arc also anterior to the  arteries. At
the great fissure these vessels divide into several branch*
es, which enter the kidney at that place.  The branches
of the vein are before and above;  those of the artery are
below, and in  the middle. Surrounded more or less by
the tranches  of those vessels, is a membranous sac, the
breadth of which extends from above  downwards. This
sac terminates in a tube that proceeds from the  lower
part of the fissure down to the bladder. The sac is deno»
min.ited the pelvis of the kidney, and the tube a ureten
each of these parts will soon be  more particularly de-
scribed.
   The substance of the kidney, as has  been already said,
is uniform in its texture, and of a reddish brown colour.
 When it is divided by an incision made lengthways, and
 from its convex to its concave edge, there appears to be
 a small difference in the different parts of it, The exte-
 rior part, which is called cortical, is rather more pale in
 colour and softer  in consistence than the internal part, It
 varies in thickness, so that some writers have described
 it as equal to  two lines, and others to one  third  of the
 kidney. In a  majority of subjects it will be found be.
 tween the two statements.
   Vol.. II                V 
154                 The Kidneys.
  The interior part is called medullary, or tubular, and
appears to be composed of very fine tubes. These tubes
are so  arranged, that a number of papillae  or  cones are
formed by their convergence, and project into the fissure
of the kidney. These papillae have been supposed to con-
sist of a substance different from either of the two above
mentioned, but they appear to be formed merely by the
tubular part.
  The  arteries, accompanied  by corresponding veins,
and by nerves and absorbent vessels,  after ramifying in
the fissure of the kidney, proceed into its substance, and
continue their aborescent ramifications until they have
arrived very near the exterior surface.  They are  so  uni-
formly distributed to the different parts of the organ, that
when the bloodvessels are injected with wax, and the
substance of the kidney is removed  from the injected
matter, as is the case in corroded preparations, the injec-
tion exhibits accurately the form of the kidney.
  The large branches of the bloodvessels occupy the va-
cuities  between the papillae in the fissure of the kidney.
When they penetrate the substance of the kidney,  they
are inclosed by* sheaths which are derived from the coat
of the gland, and are  surrounded by membrane, which
frequently contains adeps.
  There are  commonly ten or twelve papillfe  in the fis-
sure of each kidney, but there are sometimes more and
sometimes less than this  number. These papillae  are sur-
rounded by a membranous sac of a corresponding form;
the papilla being a cone, and the sac resembling the upper
part of a funnel. The  sac  is therefore called an  infundi-
bulum, or calyx.  Sometimes there are  two  papilla; in
each  infundibulum,  and then- the form of the sac is not
so regular. The infundibulum adheres to the base of the
papilla, but lies loose about the other parts of  it. Each
infundibulum communicates, at its apex, with the pelvis
of the kidney. 
      Cortical and Tubular Portions of the Kidney.   155

  The Pelvis, as has been already mentioned, is a mem-
branous sac which terminates in the ureter, exterior to the
kidney. This sac generally divides itself,  in the fissure of
the kidney, into three large irregular  branches,  each of
which very soon terminates in three or four of the infun-
dibula above described. That portion of the sac which
terminates in the ureter, is exterior to the kidney.
  When the interior parts of the  kidney are exposed  to
view, by the section above  mentioned, after the  arteries
and veins have been minutely injected,  the cortical part
will be found  to  consist  almost entirely of  the  minute
ramifications of these vessels.  Among  them  are  some
small bodies, which  are dispersed  through the substance,
like berries on a bush: these are asserted also to be com-
posed of vessels.
  The tubular part certainly proceeds from this vascular
cortical substance:   for Ruysch, and  after him  several
other injectors,  have filled these  tubes  with injection
thrown into the arteries.
  The tubuli of  which this part  is composed, seem  to
arise  obscurely from the cortical part. They soon assume
somewhat of a radiated direction, and are finally arranged
so as  to form the papillae or cones  above described.
  On these papillae or cones some of them can be traced,
uniting with each other, to form larger tubes, which ter-
minate  on the  surfaces of the papillae,  in orifices large
enough to be seen distinctly.  From these orifices  urine
may be forced out, by compressing the papillae. On this
account the tubes have been called tubuli uriniferi.
  In  the foetal state the kidney is formed  of a number  of
distinct lobuli, each of which consists of a  papilla with the
cortical  matter  connected to  its base. Soon after birth
these  lobuli coalesce; and  in two or three years the sub-
stance of the kidney appears uniform, as above described.
In some animals this  lobulated structure continues during
life: in them, and also in the foetus, each lobe appears like 
 156   Nerves and Lymphatics.  Coat of the Kidney*

a distinct organ. Although in the adult kidney this struc-
ture has disappeared, the papillae and the tubular part con-
nected with them are somewhat detached from each other,
In a manner corresponding to their original arrangement.
   The Nerves of the Kidneys originate from the semilunar
ganglion, formerly mentioned. They form a plexus round
the bloodvessels, and  go with them into the gland.
   The kidneys have internal and external absorbent ves-
sels, although the external vessels are very  small. These
absorbents pass through glands in  the lumbar region to
the thoracic duct.
   The proper coat of the kidney is said, by some anato-
mists, to consist of two laminae; but this cannot be shown
in common cases. It appears simple in its structure, and
Very flexible. It is but slightly connected to the glandular
substance which it incloses,  and may be easily peded off.
It is  reflected inwards at the fissure of the kidney, and
can be traced inwardly to some distance, forming sheaths
for the vessels.  In this internal situation it is very thin.


                     The Ureters.
   The pelvis of the kidney  terminates  exteriorly in the
Ureter, which is  a membranous cylindrical tube,  rather
flattened, and between  three and five lines in diameter,
With some variations  in this respect.
   The Ureters descend from the pelvis of the kidney so
&s to  pass  obliquely  across the psoas  muscle and  the
 great  iliac  vessels.  They  are behind the peritoneum,
 but in contact with  it. They approach the pelvis near
 the junction of the os ileum with the sacrum, and thence
 descend forwards .and  inwards, surrounded  with  loose
 Cellular membrane* to the lower part of the bladder, into
 Which they are inserted at its external and  posterior part*
 They first penetrate obliquely the muscular coat, and then
 proceed between die muscular aud  internal coats, from 
               Structure of the Ureters.            157

half an inch to an inch, in an oblique direction,, from with*
out inwards and forwards,  when they terminate by small
orifices in the internal coat, each of which is at an equal
distance (rather more than an inch) from the orifice of the
urethra, thus forming a triangle with it.
   The ureters are said to have three coats. The exterior
appears to "be derived from the cellular substance: within
it is another, which has been regarded very differently by
different anatomists; some considering it as merely mem-
branous, and others as  muscular.  If the ureter be laid
open, and the internal coat peeled off, the muscular struc-
ture of this coat is often very perceptible.
   The internal coat is called villous, or mucous, and is
continued from the internal coat of the bladder. Over this
coat mucus is  constantly spread, which defends it from
the acrimony of the urine. It is very difficult to separate
the two last mentioned  coats from each other.
   The ureters receive bloodvessels and nerves from those
of the neighbouring parts.  Their internal coat is very vas-
cular, and is also very sensible of irritation. The passage
of a small  urinary calculus can be traced  from the pelvis
of the kidney to the bladder, by the exquisite  pain and
the spasmodic affections which it often excites.
                    SECTION III.

               Of the Urinary Bladder,
  THE urinary bladder is a large sac, of a muscular and
membranous structure, which occupies the anterior part
of the cavity of the pelvis, immediately within  the ossa
pubis.                         "*•*•
  The size of the bladder is in a continued state of varia*
tion, according to the quantity of  urine secreted. When 
158            Situation of the Bladder.
moderately distended, it is of an irregular oval form, but
rather more  flat  at  its lower extremity than above. It
varies in form according to the different circumstances of
the pelvis to which it has been subjected.
   It is fixed firmly and immoveably to the pelvis, imme-
diately within the symphysis pubis; so that it is always to
be found there of a larger or smaller size. It is sometimes
completely empty, and occupies no more space than the
thickness of its coats requires. When moderately distend-
ed, it occupies a considerable portion of the pelvis: when
distention increases, it presses the parts posterior  to it
against the sacrum, and extends itself above the brim of
the pelvis into the general cavity, rising not  only to the
umbilicus, but in some cases to  the epigastric region.
   In males the relative situation of the bladder and rec-
tum is such, that the upper and middle part of the rectum
is behind the bladder; but the tower  part of the rectum,
following the curve of the os sacrum and coccygis, is be-
low the posterior part of the bladder.
   In females the vagina and uterus are situated between
the bladder and rectum; so that the connexion of these
last mentioned parts  is very different in the two sexes.
   The peritoneum is reflected at the anterior part of the
brim of the pelvis from the abdominal muscles, which it
lines, to the upper part of the bladder, which is generally
contiguous to the brim of the pelvis.  It continues  over to
the posterior side of the bladder, and passes down  upon it
some distance towards the lower part; but before it has
arrived at the bottom, it is reflected towards the sacrum.
   In males it extends from the bladder to the rectum, and
in females to the  vagina and uterus;  so that there is a
considerable  portion of the Jower part of  the  bladder
which is not invested by the peritoneum. It also  follows
that when the bladder is extended into the abdomen, and
rises above the brim of the pelvis, that part of it which
presents anteriorly, and is  in  contact with the abdorninal 
Muscular Coat of the Bladder.          159
muscles, is without a Covering of peritoneum, being be-
low it.
  The bladder is composed of a coat consisting of mus-
cular fibres, of a stratum of cellular substance immediately
within this, and of an internal lining membrane, which has
been called villous*, but, as there are no villi preceptibie
on it, may be more properly denominated mucous.
  It should be observed, that, in addition to these coats,
the bladder has a peculiar investment of the peritoneum,
as has been already described; and also of the common
cellular membrane, which is placed between it and every
part to which it is contiguous.
  The Muscular Coat of the Bladder  consists of fibres
which are not  spread over it of a uniform thickness, but
are thin in some places, and in others are collected in fas-
ciculi. They run in every direction: some appear longitu-
dinal, others circular, and some oblique;  and  there are
interstices between them which  are occupied by cellular
membrane.  The longitudinal fibres originate  from the
lower part of the bladder; and as this is the fixed part of
that viscus, it  is the place from  which these fibres must
necessarily act. These fibres are generally exterior.  There
is no arrangement of muscular fibres to which the term of
sphincter can properly be applied; but many anatomists
have thought that the fibres near the neck of the bladder,
by their separate contraction, n\ight prevent the escape of
urine:  this sentiment, however,  is contrary to that of se-
veral very respectable writers.
  The direction of the fibres, taken collectively, is such,
that, when they all contract, the cavity of the bladder is
completely obliterated.
  The cellular substance between the muscular and inter-
nal coats is dense.  It yields in a remarkable manner ta
distention, and recovers its original dimensions very easi-
ly.  From its analogy to  a similar  coat in the intestines,
it is called the  Nervous Coat. 
  160         Internal Coat of the Bladder.

   The Internal Coat of the bladder is of a light colour in
 the  dead subject, when it has been free from disease.  It
 has been called villous improperly; for the villous struc-
 ture is not apparent upon its turface. Being continued
 from  the  integuments of the body  which are extended
 along the urethra, it has been inferred, that the surface of
 this coat was formed by the epidermis; and some respect-
 able authors have supposed that they had seen  cases  in
 which portions of the epidermis of the bladder had sepa-
 rated and been discharged; but these appearances are very
 equivocal, and it is by no means certain that an epidermis
 exists there.*
   The fasciculi of fibres of the muscular coat occasion
 this  coat to appear very irregular, but these irregularities
 correspond exactly with the arrangement of the fibres of
 the muscular coat.
   When the internal coat is separated by dissection from
 the muscular, its surface is very smooth and uniform. In
 the recent subject, when no disease has previously existed,
 it is always spread over with mucus of a light  colour, but
 nearly transparent, which can  be easily scraped off. This
 mucus is spread upon  the surface so uniformly, that  it
 must be derived from sources which are  situated upon >
 every part  of  the surface; but these sources are not very
 obvious. On the membrane  of the  nose the orifices of
 many mucous ducts  are very visible, but such orifices are
 not to be seen on this surface. Haller mentions that he  has
 seen mucous glands near the neck of the  bladder;  and  it
 is stated by  the pupils  of Desault, that, in one of  his
 courses, he pointed  out a  number of these glands, in a
 subject who had been afflicted with a catarrhal affection
of the bladder.

  * In the fauces and the follicles of the tonsils an effusion of coagu.
lable matter, in consequence of inflammation, often forms crusts, that
may be mistaken for sloughs of the integuments, although those inte-
guments remain entire. 
Mucus of the Bladder.             161
   Notwithstanding that the sources of this mucus are ob-
scure, the quantity of it is sometimes immense.  In some
cases, where the secretion is increased bv the irritation of
a calculus in the bladder, the urine is rendered somewhat
viscid and white coloured by the mucus mixed with it;
which, after tge  urine has  been allowed to remain for
some time, subsides in such  quantities as demonstrates
that many ounces must be secreted in  the course of the
twenty-four hours. The same circumstances occur, with-
out the irritation  of calculus, in the disease called catar-
rhus vesicae.*
   It is probable that, in healthy persons, a great deal of
it passes off unperceived, being dissolved or diffused in the
urine. From the quantity and the regular diffusion of this
mucus on the surface of the bladder, there is the greatest
reason for believing that  it is effused frgm every part of
the surface; and it  is a question that has not b;.en decided,
whether it is discharged  from glandular ducts too small
to  be perceived, or from  the  exhalent  extremities of the
bloodvessels. It is probable that the use of it is to defend
the internal coat of the bladder from  the acrimony of the
urine.
   The symptoms  of a stone in the bladder, as well as of
several other diseases, evince that this coat is endued with
a great degree of sensibility.
   It is evident that  the  essential parts in  the general
structure of  the bladder  are the muscular coat and the
internal coat last described: but in addition to the account
of them, there are  some other important circumstances to
be  noted in  the description of this  organ. It has been
already stated, that the form of the bladder was an irregu-
lar oval,  although  it  was somewhat  varied  in different

  * In some cases this mucus soon  becomes putrid, and during the
putrefactive process deposits a substance which appears to be calca-
reous.
  Vol.  IL                X 
 162           Orifice of the Urethra,

 persons. The oval form is not much altered at the part
 called the neck of the bladder, where the urethra passes
 off from it.  The orifice of the urethra is situated ante-
 riorly at the lowermost part of the bladder.  On the low-
 er surface of the  urethra, at its commencement, and  on
 the bottom of the bladder,  immediately connected \<  ith
 the urethra, is situated the Prostate Gland,  (to be here-
 af er described with ihe organs of generation,) uhieh ^ a
firm body, that adheres strongly both to the bladder ai d
 urethra.  This circumstance  gives particular firmness and
 solidity to that part of the bladder. It has also  bi. en ob-
 served, that the  bladder is attached firmly to  the  ossa
 pubis, at its neck, about the origin of the urethra  E  ch
 of these circumstances have an effect upon  the  orifice of
 the urethra; and when the bladder is opened, and this ori-
 fice is examined  from within, it appears to  be kept open
 by  the connexion of the bladder with the  prostate, and
has been very jus'ly compared to the opening of the neck
of a bottle  into the great cavity of that vessel.*
   The orifices of the two ureters are at equal  distances
from  the orifice  of the urethra, and form with  it the an-
 gles of a triangle. That  part of the internal surface of
 the bladder which is within this triangular space, is  more
 smooth than the remainder of the same surface,  probably
 in consequence  of the  adhesion  of  the bladder to  the
 prostate, and to other parts exterior to it.
   That part of the bottom of the bladder which is imme-
 diately behind the triangular space, is rather lower than

  * The late Mr. Lieutaud, and after him the French anatomists of
 the present day, have described a small tubercle at the lower and
 posterior part of the orifice of the urethra, which resembles ihe uvu-
 la in form. It has not been noticed here; and M. Boyer states,  that
 it is often scarcely preceptible. He, however, makes a remark which
 is very worthy of attention, viz. that it is very subject  to enlarge-
 ment in old people, foiming a tumor  which impedes the discharge
 of urine. Sabatier has also made the Fame observation 
         Ligaments and Vessels of the Bladder.      163

this space; and but a small portion of cellular membrane
exists between it and  the  rectum in  males,  and the va-
gina in females.
   The upper part  of  the bladder is  connected with the
umbilicus by means of a ligament, which passes between
the peritoneum and the abdominal muscles. This liga-
ment  consists  of  three cords. One of these,  which  is
in the middle,  arises from  the  coats of the bladder, and
was,  in the foetus, the duct  called urachus; the other
two, which are connected to the bladder principally by
cellular membrane, were originally the umbilical arte-
ries.* The middle cord is of a light colour and fibrous
structure; it is thickest at the bladder, and gradually di-
minishes as it approaches the umbilicus. In a few in-
stances it has  been found to be hollow. In its progress
to the umbilicus it becomes more or less blended with
the linea alba, or the tendons of the abdominal muscles.
The other cords are generally solid. After passing from
the umbilicus to the bladder, they continue on the sides
of that viscus, and finally terminate at the hypogastric or
internal iliac artery.
   In the very  young subject these cords are  invested by
distinct processes of  the peritoneum, but their position
is exterior to the peritoneum.
   As the bladder is situated very near most of the large
ramifications of the hypogastric  artery in the  pelvis,  it
receives  branches from several of them; viz.  from the
umbilical arteries before they terminate; from the pudic;
from  the obturators, &c.  These branches ramify in the
cellular membrane exterior to the muscular coat, and
also in the cellular substance between the  muscular and
internal coats.  It has been  conjectured,  that their termi-
nations in exhalents on the surface of  the bladder are re-
markably numerous.

  * See the accounts of these parts in the description of the Abdo-
men of the Foetus. 
164
General Observations.
   The veins correspond with the  arteries, but they arc
very numerous on the lower and lateral parts of the blad-
der, and by uniting with the veins  of the rectum form a
remarkable plexus.
   The Lymphatic  Vessels  of this  organ do  not appear
more numerous  thun those of other parts.  They pass on
each side the bladder in the course of  its bloodvessels,
and unite with  the larger  lymphatics,  and the glands
which lie upon the great bloodvessels on the sides of the
pelvis.
   The Nerves of the bladder are derived  both from the
intercostal nerve and from the nerves  of the medulla spi-
nalis, which pass off  through  the sacrum; and therefore
the bladder is more affected than the viscera of the abdo-
men, by injuries *of the medulla spinalis.

    The action of  the muscular fibres of the  bladder in expelling
      urine, and the effect of those fibres which are situated near the
      orifice of the urethra in retaining  it, can be considered with
      more advantage after the structure of  the urethra  and the
      muscles connected with that canal  have been described.
        It has been stated, that the  internal coat  of the bladder is
      very sensible; but it may be added, that in consequence of dis-
      ease about the neck of the bladder, the natural sensibility ap-
      pears most inordinately increased.  When the intensity of pain
      which accompanies these complaints, the frequent recurrence
      of paroxysms, and their duration,  are taken into view, there
       seems reason to believe that none  of the painful affections of
       the human race exceed  those which  arise from certain  dis-
       eases of the bladder. Happily these diseases  are not very
       common.
        The function of the kidneys is to secrete urine, and that of
       the bladder to retain it until the proper time for evacuation.
        The urine may be regarded as an excrementitious fluid,
       which contains many substances in solution that are constant-
       ly found in  it, and  many others that are  occasionally in it,
       which are taken as aliment or medicine, and pass to the blad-
       der with little, if any, change. The odour of the rose leaf, the
       colour of rhubarb, &c. are occasionally perceived in urine.
        The substances constantly found in urine  are numerous. 
General Observations.
165
The chemical account of the subject is so long, that it cannot
be detailed here; but  the student ought to make himself ac-
quainted with it, and he will read with great advantage John-
son's History of Animal Chemistry,  vol. 2d, page 363; and
also Thompson's Elements of Chemistry, page 333.
» 
166
                   CHAPTER V.

         OF THE MALE ORGANS OF GENERATION.

THESE organs consist, 1st, of,the Testicles,  and their
appendages.
  2d. Of certain parts denominated the Vasicula Semi*
nales and the Prostate Gland, which  are situated near
the commencement of the urethra, and are subservient to
the purposes of generation.
  3d. Of the Penis,
                     SECTION 1.

         Of the Testicles and their appendages.
  THE Testicles are two bodies of a flattened oval form.
Each of them h is a protuberance on its upper and poste-
rior part called  Epididymis, and  is connected to  parts
within the cavity of the abdomen by a thick cord, which
proceeds to it through the abdominal ring.  Each testicle
also appears to be contaiiied in a sac, which is suspended
by this cord and covered by the common integuments.
  That portion of  the common integuments which forms
the external covering of the testicles, is denominated

                  .».
                  1  The Scrotum.
  The skin of the  scrotum, although it is very often in a
state of corrugation,  has the same structure with that on
other parts of the  body, except that it is rather thinner 
Structure of the Scrotum.           167
and more delicate. The superior delicacy of this portion
of the skio is evinced by the great irritation produced by
the application of stimulating substances, and the desqua-
mation of the  cuticle, which seems to be the effect of ir-
ritation. There are many sebaceous follicles in this portion
of skin; and after puberty there are often a few long hairs
growing out of it, the bulbs of which are often very con-
spicuous. There is  a small raised line in the middle of
this skin, which commences at the root of the penis, and
proceeds backwards, dividing it into two equal parts: this
line is denominated  Raphe.
   The corrugation which so often takes place in the skin
of the scrotum, appears to be occasioned by the contrac-
tion of certain fibres, which are  in the cellular substance
immediately within it. This cellular substance appears to
be attached in:a particular way to the skin; and it also in-
vents each testicle in such a manner,  that  when they are
withdrawn a cavity is left in it. It has long been observed,
that no adipose matter ie found in  this cellular substance;
but it is often distended with water in hydropic diseases.
As the  contraction  and corrugation of the scrotum has
been imputed to this substance, it has been examined with
particular attention by anatomists, and very different sen-
timents have been entertained respecting it  While some
dissectors  have  asserted  that muscular fibres  could  be
seen in it, which they have denominated the Dartos Mus-
cle; others have said that this substAce was simply cellu-
lar, and withort any  muscular fibres.  This difference of
sentiment  may  possibly have arisen from the different
conditions of  this part in different subjects; for in some
cases there are appearances which seem to justify the as-
sertion that muscular fibres exist irr^is structure.
   After the testicles are removed,-so'as to leave the cel-
lular substance connected with the skin, if the scrotum be
inverted, and  this substance  examined in a strong light,
many fibres will appear superadded to the common cellu- 
168         Action of the Dartos Muscle.
lar* structure;  and sometimes their colour can be distin-
guished  to be red.  It is not asserted that this will be
uniformly the  case; but certainly it has often been ob-
served in this way.
   The existence of an organ which possesses the power
of contraction, within the skin of the scrotum and con-
nected to  it, is evinced by the  corrugation which takes
place when the scrotum is suddenly  exposed  to cold,
after  having been very warm. This corrugation  occurs
in a very sudden  and rapid manner, in some cases, in
which the  wounded  scrotum is  thus  exposed for the
purpose of dressing: for  example, upon removing an
emollient  poultice from  this part some  days after the
operation for the cure of hydrops testis, by incision;  if
the air of the chamber be cool,  a motion of the scrotum
will  take  place, almost equal to the peristaltic  move-
ments of the intestines.
  The Arteries of the  scrotum are derived from two
sources. One or two small  arteries, which arise from the
femoral artery,  between Poupart's ligament and the ori-
gin of the  profunda, are spent upon it.  These are called
the external pudic arteries.  It also receives some small
branches from  the  internal pudic artery.
  The Nerves of the scrotum are principally  derived
from the lumbar nerves.

                 The Spermatic Cord.
  The cord which proceeds to the testicle through the
abdominal  ring, appears at first  view  like a bundle of
muscular fibres;  but it consists of  an artery and veins,
with many lymphatic vessels and nerves,  and also the
excretory duct of  the testicle,  connected to  each other
by cellular substance, and  covered by an  expansion  of
muscular fibres which are  derived from the lower edge
of the interna*! oblique muscle of the abdomen, and con- 
   Cremaster Muscle.  Bloodvessels of the Testicle.   169

tinue from it to  the upper part  of  the testicle. These
fibres constitute the Cremaster Muscle.
  The artery above  mentioned is called the Spermatic.
It commonly arises from the front  of  the aorta,  very
near its fellow, at a small  distance below the emulgents:
and  is not much  larger than a crow's quill. It proceeds
downwards behind the peritoneum and before the psoas
muscle and ureter. While it is in contact with the psoas
muscle, it joins the  ramifications of the vein.  It after-
wards meets  the vas deferens,  and proceeds through the
abdominal ring to 4he  back part  of  the testis. Before it
arrives at the testis it' divides into several branches,  two
of which generally go to the epididymis, and  the others
penetrate the  tunica albuginea on the upper and back of
the testicle, and ramify very minutely on the fine membra-
nous partitions which exist in that body.
  In addition to the  spermatic artery, there  is a small
twig from the umbilical branch of the hypogastric, which
passes to the spermatic cord along the vas deferens.
  The branches of the spermatic vein are much larger
than those  of the artery:  several of them proceed from
the testicle so as to correspond with the arterial branches;
and in addition to these  there are many smaller, which
also  arise from the testicle  and  epididymis.  In their
course up the cord they ramify, and again unite, so as to
form a considerable plexus, which is called the Corpus
Pampiniforme, and constitutes a considerable part of the
volume of the spermatic cord.
  As they proceed upwards they unite into  a  few larger
veins; and  finally, on  the  psoas  muscle, they generally
form one trunk, which continues upwards so as to unite
with the vena cava qn the right  side and the  emulgent
vein  on the left.
  Sometimes, but not  often, there are several spermatic
veins on each side.
  The Lymphatic Vessels of the testicle are very numer-
  Vol. II.                Y 
170   Lymphatics and Nerves of the Spermatic Cord.

ous, considering the size of the organ. Six or eight, and
sometimes more, large trunks have been injected, run-
ning upon the cord, and continuing to the glands on the
back part of the abdomen.
  The Nerves of the testicle  are  derived  from those
which supply the viscera of the abdomen, and are to be
found in  the cord although they can scarcely be traced
to the testicle. A small  plexus, called the spermatic,  is
formed by fibres from  the renal plexus and from the
sympathetic nerve.  These fibres accompany the  sper-
matic vessels, and in all  probability enter  the  body  of
the testis and the epididymis.  The spfcrmatic cord and
cremaster  muscle receive filaments  from  the  second
lumbar nerve.
  In  addition to these vessels,  the Vas Defet&ns, which
is much  firmer than either of them, is always to be dis-
guished in the back part of the cord.
  They are all covered in front and on the sides by the
cremaster  muscle,  which passes  with  them from the
lower margin of the internal  oblique, through the abdo-
minal ring, and continues to the uriper  part of the ex-
ternal coat of the testicle,  which is a sac apparently  con-
taining that organ, and upon this sac it is spread out and
terminates.

                 The Tunica Vaginalis.
   The External Coat of the testicle, which is commonly
called the  Tunica Vaginalis-, is a complete sac which  in-
closes the  testicle as the pericardium  incloses the heart.
It covers the  body of the testicle and  epididymis, and
adheres  closely to them.  It is  then reflected from  them
so as to  form a loose sac, which ap'pears to contain them.
The  cavity of  the tunica vaginalis commonly extends
above the  body of the testis up the cord, and is oval or
pyriform.  This sac. is so  reflected from  the body of  the 
Coats of the Testicle.              271
testicle,  that  there is a place on  the  upper and  back
part of that body  at  which the bloodvessels enter it,
without penetrating the sac.
   It resembles the peritoneum and other serous mem-
branes in  texture, and is therefore  thin and delicate.  It
always contains a quantity of moisture, sufficient to lu-
bricate the surface which it forms.
   When the tunica vaginalis is laid open, the testicle ap-
pears as if it were contained in the posterior part of its
cavity.
   The testicles, as has been already stated, are of a flat-
tened oval form.;Their position is somewhat oblique, so
that their  upper extremities look  upwards and forwards,
their lower extremities downwards and backwards, and
their edges present forwards and  backwards.
   The body of the testicle is very firm, in  consequence
of its inclosure in a very firm coat called  Tunica Albugi-
nea. Upon the upper and posterior part of  it is the pro-
tuberant substance, called Epididymis, which is less firm,
being exterior to the tunica albuginea. The bloodvessels
of the testicle  pass into it on the  posterior edge, at some
distance below the upper end.

                The Tunica Albuginea,
   In which the body of the testicle is completely inclose
ed, is firm and dense;  and upon  this coat its particular
form depends. It is  of a whitish colour, and has a smooth
external surface.  It is thick as well as strong.  The epi-
didymis is  exterior to it. It is  only perforated by the
bloodvessels,  lymphatics and nerves, and  by the vasa
efferentia,  which carry out the secretion of  the testis.
One portion of the tunica  vaginajis adheres very closely
to it, and the other appears to contain it. The  portion
which adheres to it is with difficulty  separated, but it  is
a distinct  membrane. 
172    Form and Connections of the Epididymis.
                   The Epididymis
  Differs in colour from the testicle, being more or less
reddish. It commences at the upper and anterior extre-
mity of the testicle, and passes down the posterior edge
to the lower end.
  At the  commencement  the  epididymis is somewhat
rounded in form, and  its upper part, or head, has been
called the globus major:  as it descends it lessens, and
about the  middle of the testicle it is flattish.
  It is firmly attached to the body of the testicle, at the
upper end, where the vasa efferentia pass to it; and it is
also attached to it  below; but at the middle it appears
nearly detached from it. It ha^s therefore been compared
to an arch resting with its two extremities on the back  of
the testis; it is, however, in contact with it at its middle;
but about the middle it only adheres by one  of its edges
to the body of the testis, and generally by its internal
edge. It has a coat which is  less  firm than  the  tunica
albuginea of the testicle, described on the last page. The
tunica vaginalis of the  testicle is so reflected as to cover a
great part of the epididymis which is not in contact with
the testicle, and also those surfaces of the epididymis and
testis which are in contact with each other and do not ad-
here.

               The Body of the Testicle.
   When the tnnica albuginea  is  cut  through, and the
substance of the testicle examined, it appears to consist
of  a soft pulpy substance  of a yellowish brown colour,
which is  divided into separate portions by very delicate
septa, attached to the internal  surface of the  tunica albu-
ginea at the posterior part of the testicle.  After macera-
tion, by using  a fine needle to detach them from the cel-
lular substance, these threads may be drawn  out to a
great length. In some animals they are larger than in the 
     Tubuli, Septa and Bloodvessels of the Testicle.  173

human species; in them, it is said, they are evidently hol-
low, and that very small bloodvessels appear in their coats.
When mercury is injected into the vas deferens, or excre-
tory duct of the testis, in a retrograde course, it  can be
perceived in these ducts in the human subject.
   These delicate septa, or partitions, are  united to the in-
ternal surface of the tunica albuginea at the posterior part
of the testicle,  at  which place there is a  body called
 Corpus Hxghmorianum, which has been regarded very dif-
ferently by different anatomists. It is a long  whitish sub-
stance, which extends lengthwise on the  posterior part
of the testis;  and was  supposed by  Haller  to  resemble
one of the salivary ducts. It is now, however,  generally
agreed to be of a cellular structure, and to contain and
 support the ducts which  pass from the  substance of the
 testicle to the epididymis.
   The bloodvessels  pass jnto  the body of the  testicle
 upon these septa, and are continued from them to the fila-
 ments or tubes of which  the body of the testicle consists.
 As in some  animals bloodvessels are  distinguished on
 these tubes, there  is the  greatest reason to believe that a
 direct communication subsists between them, without the
 intervention of any other structure, no other structure hav-
 ing been discovered: but at the same time it ought to be
 observed, that these  tubes  have  not yet been injected
 from the bloodvessels.  Some ingenious anatomists have
 injected the artery going to the testicle so successfully,
 that the injection has passed from it into  the veins coming
 out of the testicle;  but it is not now said by any of them,
 that they have filled the tubes in this manner.
    Mercury will pass into these vessels  from the excre-
 tory duct of the testicle; and by means of an injection in
 that way, the structure of the testicle can be unravelled.
    This structure is as follows:  The cavity formed by the
 tunica albuginea is divided into a number of apartments by
 the very thin septa, or partitions, above  mentioned. From 
 174    Structure of the Testicle and Epididymis.

 the filamentary or tubular matter which fills each of these
 chambers, proceeds a number of small tubes or vessels,
 which observe a straight course; they are therefore called
 Vasa Recta. These vasa recta unite with each other and
 form a network  on the back of the testis, within the tu.
 nica  albuginea,  which is called Rete Testis. From this
 network other vessels, from twelve to eighteen in number,
 denominated Vasa Efferentia> proceed through the albugi-
 nea to the epididymis. These vessels are convoluted in
 such a manner as to form bundles of a conical form, which
 are called Com  Vasculosi. The number  of these corres-
 ponds with the number of the vasa efferentia,  and they
 compose about one third  of  the epididymis,  viz. all  the
 upper part of it. The single tubes which form each of.
 these cones, successively  unite into one  duct,  which is
 convoluted so as to form  all  the remainder of the epidi-
dymis. The lower part of the epididymis is turned up-
wards on the back  of  the testicle, the tube gradually  en-
larges and is less  convoluted, an^finally becomes straight:
it then takes the  name of Vas Deferens, and continues on
the back of the testicle to the spermatic cord.*
  A small solitary  vessel or  duct, has been observed by
 Haller, Monro, and several other anatomists,  to  proceed
from the upper  part  of the epididymis: sometimes it
                              T
  * De Graff appears to have been the first anatomist who made
 much progress in the successful investigation of the structure of the
 testicle; and Haller  ought  to be mentioned next to him, on account
 of the plate exhibiting this structure, and the explanation of it, which
 he published in the  Philosophical Transactions of London, for 1749.
 This plate has been republished by the second Monro, in the Lite-
 rary and Physical Essays  of Edinburgh, and also in  his Inaugural
 Thesis. Haller has  likewise republished it in his Opera Minora. It
 represents  not only the vasa efferentia and the cones  formed by
 their convolutions, but also the rete testis and the vasa recta. Haller
 could inject no further than this; but Monro and Hunter soon after
 succeeded so as to fill a considerable portion of the body of the tes-
 ticle with mercury,  injected by the vas deferens. 
Course of the Vas "Deferens.
175
unites to the epididymis  below,  and sometimes it  pro-
ceeds upwards.  The nature of this vessel has  not been
ascertained with certainty.

                  The Vas Deferens
   Is a very firm tube about two lines in diameter, which
is not perfectly cylindrical exteriorly, although the cavity
formed by it is so.  This cavity is so small in diameter,
that it  will only admit a  fine bristle. The coats  of the
duct have, of course, a considerable thickness. The in-
ternal  coat forms a soft surface, analogous to that of the
mucous membranes: the external is firm, and its texture
resembles that of cartilage. Owing to the small size of
the cavity, the internal coat has not been separated from
the external.
   It passes upward^ in the posterior part of the spermatic
cord, and continues  with it through the abdominal ring,
under  and exterior  to the peritoneum;  soon after this it
leaves the cord and dips down into the cavity of the pel-
vis, forming  a curve on the side of the bladder, and pro-
ceeding  backwards, downwards  and  inwards. In this
course it crosses the ureter, and passes between  it and the
bladder. On the lower part of the bladder the two vasa
deferentia approach each other so gradually, that they ap-
pear to be nearly parallel.  They proceed forward  be-
tween  the vesicular seminales, which are two bodies irre-
gularly convoluted, that are placed in a  converging posi-
tion with respect to each  other, and communicate  with
the vasa deferentia. The vasa deferentia finally terminate
almost in contact with each other in the posterior part of
the prostate gland, where they  perforate the urethra. At
the distance  of  about  two inches and a half from their
termination they enlarge in diameter,  and become some-
what convoluted. At the posterior margin of the prostate
they come in contact with the anterior extremities of the 
176       Structure of the Vesicula Seminales.

vesiculae seminales, and unite with them. After this union
they diminish in size, and become conical; and passing
a short distance  through the substance of the  prostate,
during which they approach each  other  more  rapidly,
they penetrate the  urethra, so  as to open in it on each
side  of a small tubercle,  called the Caput Gallinagtnis,
soon to be described.
                     SECTION II.

   Of the Vesicula Seminales and the Prostate Gland.
  THE  Vesicula Seminales are two bodies of a whitish
colour, and irregular form, being broad and flat at their
posterior extremities, and  terminating  in a point  at the
other. Their surfaces are so convoluted,  that they have
been compared to those of the brain. They are situated
between  the  rectum and bladder, and are connected to
each by cellular membrane.
  When the vesiculae  seminales are laid  open by an in-
cision, they appear to consist  of cells of  a  considerable
size, irregularly arranged;  but when they are carefully
examined exteriorly, and the cellular  membrane about
them is detached and divided, they appear to be formed
by a tube of rather more than  two lines diameter, and se-
veral inches in  length, which terminates, like the caecum,
in a  closed extremity. From this.tube proceed from ten to
fifteen short branches, which are closed in the  same man-
ner.  All  these tubes are convoluted so as to assume the
form of the  vesiculae seminales above described; and they
are fixed in this convoluted state by cellular membrane,
which firmly connects their different parts to each other.
It is obvious, that tubes thus convoluted, when  cut  into,
will  exhibit the appearance of cells, as in the present in-
stance. 
Function of the Vesicula Seminales,       177
  This convoluted tube, composing the vesiculae semi-
nales, terminates in a very short duct, which is nearly of
the same  diameter with the vas deferens, and this duct
joi-s the vas deferens so as to form an acute angle.
   From the union of the vesiculae seminales with the vas
deferens on each side,  a canal,  which  seems to be  the
continuation of the vas deferens, proceeds through part of
the prostate  to  the  urethra, which it perforates. These
canals  are from  eight to twelve lines in length; they are
conical in form, their largest extremity being equal to
the vas deferens at that part.
   If air or any other fluid be injected through the vas de-
ferens  into the urethra, it will pass at the same time into
the vesiculae seminales, and distend them. It has been ob-
served, that a fluid passes  in this manner much  more
readily from the vasa deferentia into the vesiculae semi-
nales, than it does from these last mentioned organs into
the duct.
   These organs were  generally regarded as reservoirs of
semen, and analogous to the gall bladder in  their func-
tions, until the late Mr. J. HunteY published his opinion
that they were not intended to contain semen, but to se-
crete a peculiar  mucus subservient to the purposes of ge-
neration.
   He states the f.lldWing facts in support of his opinion.
   A fluid, very  different from semen, is found after death
in the  vesiculae  seminales.
   In persons  who have lost one testicle, a considerable
time before  death, the vesiculae seminales  on each side
are equally distended with this peculiar fluid.
   The sensation arising from redundance of the secretion
of the  testes, is referred to the testes, and not to the vesi-
culae seminales.
   In some animals,  there is no connection between the
vasa deferentia and the vesiculae seminales.
   Vol. JI.                Z 
178.
Prostate Gland.
   See Observations on certain parts of the Animal Eco-
nomy, by John Hunter.


                 The Prostate Gland
   Is situated on the under and posterior part of the neck
of the bladder, so as  to surround the lower side of the
urethra.  Its form has some resemblance to that of the
chesnut,  but it has a  notch on the basis like that of the
figure of the heart on playing cards, and it is much larger
than the chesnut of this part of America. The basis of this
body  is  posterior, and its apex  anterior;  its position is
oblique, between the rectum and the symphisis pubis. On
the upper surface is the groove occupied by the urethra;
below there is in some cases a small furrow, which, in
addition to the notch above, gives to the gland an appear-
ance of being divided  into two lobes.
   It adheres to the urethra and neck of the bladder. Its
consistence is very firm and dense, resembling the indu-
ration of scirrhus rather more than the ordinary texture
of glands.
   This gland receives small branches from the neighbour-
ing bloodvessels, and  has  no artery of considerable size
exclusively appropriated to it.
   As it lies in close contact with the urethra, the ducts
which pass between it and the urethra are not to be seen
separate from these bodies; but ducts can be seen in the
substance of the gland, which perforate the urethra, and
open on  the sides of the caput gallinaginis to the number
of five or six on each  side. By pressure a small  quantity
of a whitish fluid can be forced from these orifices, which
is rather  viscid, and coagulable in alcohol.
   The particular use  of this fluid is not known. 
Penis.                     179
                    SECTION IH

                    Of the Penis.
   THE penis, when detached from the bladder, and the
 bones, to which it is connected, and divested of the skin
 which covers it,  is an oblong body, which is rounded  at
 one extremity and bifurcated at the other.
   It is composed of three parts, viz. two oblong bodies,
 called Corpora Cavernosa, which, at  their commence-
 ment, form the bifurcated portions, and then unite to com-
 pose  the body cAhe organ; and a third part, of a spongy
 texture, which is connected to these bodies where they
 unite to each other, on the under  side, and continues at-
 tached to them during the whole extent of their union,
 terminating in an expanded  head  which covers the ante-
 rior extremities of  the corpora cavernosa. The urethra
 passes from the neck of the bladder, on the under side of
 the penis, to its anterior extremity, invested by this third
 body, which is therefore called Corpus Spongiosum Ure-
 thra.
   The two  bifurcated  extremities are attached each  of
 them to one of the crura of  the pubis and ischium; and
 they unite to form the body  of the penis immediately an-
 terior to the symphisis pubis, to which the lower part of it
 is also attached; so that the penis is firmly connected to the
 middle of the anterior part of the pelvis. The urethra
 proceeds from the neck of the bladder, between the crura
 of the ischium and  pubis and  the crura of the penis,  to
join the body of the penis at  its commencement, and near
 this place its connection with the corpus spongiosum be-
gins; so that there is a small portion of the urethra between
the neck of the bladder and the commencement  of the
corpus spongiosum, which is not  covered by the corpus 
180           Corpora Cavernosa Penis.

spongiosum.  This is called the membranous part of the
urethra.
  The penis, therefore, consists of two oblong bodies of
a cellular structure, which originate separately, but unite
together to form it; and of the urethra, which joins these
bodies immediately after their union, and is invested by a
spongy covering, which by its expansion forms the ante-
rior extremity not only of  the urethra  but of the whole
penis. These three bodies,  thus arranged and connected,
are covered by cellular membrane and skin in a manner
to be hereafter described.


               The  Corpora Cavernosa,
  Which compose the body of the penis, are two irre-
gular cylinders,  that are formed by a thick dense elastic
membrane, of  a  whitish   ligamentous  appearance and
great firmness.  They are  filled  with  a substance of  a
cellular structure, which  is occasionally distended with
blood.  The crura of these cylindrical bodies,  which are
attached to the crura of the ischium and pubis, are small
and  pointed at the commencement, and  are  united to
the periosteum  of the bones. In their progress upwards
they enlarge, and at the symphisis  of the  pubis they
unite so as to form one  oblong  body,  which retains the
appearance of a union of two cylinders applied to each
other lengthways; for above there is a superficial groove
passing in that direction,  which is occupied by a large
vein: and below there is a much deeper groove, in which
the urethra is placed. Between these grooves is a septum
which divides one side of  the  penis from the  other.  It
appears to proceed  from  the  strong membrane which
forms  the penis, and is composed of bundles of fibres,
which pass from  one  groove  of the penis to the other,
with many intervals between them, through which blood
or injection passes very freely.  Sometimes these bundles 
            Cells of the Corpora Cavernosa.        181

of fibres, with their intervals, are so  regularly arranged,
thai  tht y have  been compared to the teeth of a comb.
This septum extends from the union of the two crura to
their termination.
   Each of these cylinders is penetrated by the  main
branch  of  the pudic artery, which is  about equal in size
to a crow's quill. These arteries enter the corpora caver-
nosa near th»:ir union, and  continue through their whole
extent,  sending off branches in their  course: the tumes-
cence and erection of the penis is unquestionably pro-
duced by the blood which flows through these vessels into
 the penis.
   The  interior structure of the penis, when examined in
 the recent subject, is of a soft spongy nature, and seems
 stained with blood. If any fluid be injected through  the
 arteries this substance appears cellular, and may be com-
 pletely distended by  it.  When  air is  injected,  and the
 structure  becomes dry, the penis may be laid open; the
 cellular structure then appears as if formed by a number
 of laminae and of filaments, which proceed from one part
 of the internal surface of the penis to another, and form
 irregular cells. It has been compared to the lattice-work in
 the interior of bones; and it  is suggested by M. Roux,
 that the fibres of which the structure  consists resemble
 those of the strong elastic coat of the  penis.* If these cells
 are filled  with coloured wax, injected by the artery, and
 the animal substance is then destroyed  by  placing the
 preparation in a  corroding liquor, the wax which remains
  shows that the  membranes  forming the cells  are  very
  thin.
    These cells communicate  freely with each other;  and
  therefore, if a pipe be passed through the strong coat of
  the penis, the whole of them can be filled from it by the
 ordinary process of injection.
• The late J. Hunter thought they were muscular. 
 182          Corpus Spongiosum. Bulb.


                     The Urethra
  Is a membranous canal, which extends from the neck
of the bladder to the orifice at the extremity of the penis;
and  for a very great part of its length is invested by a
spongy structure, called the corpus spongiosum urcthrae.
It proceeds from the neck of the bladder  along a groove
in the upper part of the prostate; from the  prostate it con-
tinues between the crura of the penis until their junction:
it then occupies the great groove formed  by the corpora
cavernosa on the lower  side of the penis, and continues
to the orifice above mentioned.  At a small distance from
the  prostate gland the spongy substance which invests it
commences, and continues to its termination. After this
spongy substance has arrived at the termination of the
corpora cavernosa, it expands and forms a body of a par-
ticular figure which covers the extremities of the corpora
cavernosa, and is denominated the Glans Penis.
  The Corpus Spongiosum begins at the distance of eight
or ten lines from the anterior part  of the prostate.  It is
much larger at its commencement than at any other part
except the glans, and this enlarged part is called the Bulb.
It surrounds the whole  of the urethra, and with the ex-
ception of the bulb and the glans penis,  is  of a cylindrical
figure. It is formed by a membrane which has some re-
semblance to the coat of the penis, but is much thinner,
and by a peculiar spongy substance, which occupies the
space between the internal surface of this  membrane and
the  external  surface of the canal  of the  urethra. The
membrane and the spongy substance,  form a coat to the
urethra, which, with the exception of the enlargement be-
fore mentioned, is about two lines thick. It is situated in
the  groove on the  lower side of the penis,  and its coat
adheres firmly to the coat of the penis.
  The Bulb, or first enlargement of the corpus spongio-
sum, is oblong, and rather oval in form; it is marked by a 
         Structure of the Corpus Spongiosum.      183

longitudinal depression in the middle, which is very su-
perficial. It consists entirely of the spongy substance above
mentioned.
  The Glans Penis is also composed of the same spongy
substance,  but the coat which covers it is more thin and
delicate than that of the other parts of the urethra.  The
lower surface of the glans is fitted to the extremities of
the corpora cavernosa, but it is broader than the corpora
cavernosa,  and therefore projects over them on the upper
and lateral  parts of the surface of the penis. The edge of
the piominent part is regularly rounded, and is denomi-
nated the Corona Glandis.
  Several small arteries pass to this spongy structure. The
pudic artery, as it passes on each side to the corpora ca-
vernosa, sends a branch to the bulb of the urethra.  The
same vessel in  the substance  of the penis, also sends
branches to the urethra:  and the  artery on the back of the
penis terminates in small branches, which penetrate the
substance of the glans.
   By these vessels  blood is carried to the spongy sub-
stance of the urethra, which is occasionally distended in
the same manner that the  cavernous bodies of the penis
are distended during the erection of that organ.  But the
cellular structure of this organ is not so  unequivocal as
that of the penis; for if it ,be injected with coloured wax,
and corroded  in  the usual manner,  the injected matter
will exhibit an appearance which has the strongest resem-
blance to a convoluted vessel, like the vas deferens in the
epididymis.


              The Canal of the Urethra,
   Which conveys  the urine from the bladder, is a very
important part of the urinary organs. It consists of a vas-
cular membrane with a smooth surface, which is perfo-
rated by the orifices of many mucous follicles, some of 
184         Internal Surface of the Urethra.
which are of considerable size. It is extremely sensible,
and has so much power of contraction, that some persons
have supposed muscular fibres to exist in its structure.
  It  is differently circumstanced in different parts  of its
course. While surrounded with the prostate it adheres
firmly to that body,  seeming to be supported by it; and
here its diameter is larger  than it is farther forward. On
the lower or posterior side of this portion of the urethra,
is an oblong eminence, called Verumontanum, or Caput
Gallinaginis, which commences at the orifice of the ure-
thra,  and continues  throughout the  whole  portion that
is surrounded by the prostate  gland, terminating at the
point of that body. The posterior extremity of this tu-
bercle begins abruptly, and soons  becomes thick and
large; anteriorly it gradually diminishes  to a line, which
is sometimes  preceptible for a considerable distance  in
the  urethra,  in  a straight forward direction.  In the
upper edge  or top of this body is a groove, which is pro-
duced by a  mucous follicle; on the lateral surfaces, ante-
rior to the middle, are the orifices of the common  ducts
of the vesiculae seminales and  vasa deferentia (see page
176,  7,) which  are  sufficiently large to receive a thick
bristle.  Near these,  on each side, are five or six smaller
orifices of the excretory ducts of the prostate gland. At
a small distance before the caput gallinaginis are the open-
ings of two ducts, one on  each  side, that lead to small
glandular bodies called Cowper's glands,  which are  situa-
ted on each side of the urethra below the bulb, but are
covered by the accelerator  urinae muscle.
  The diameter of the urethra lessens after  it leaves the
prostate.  That portion of the canal which is between
this gland and the bulb,  without investment, and there-
fore called the membranous part, is the smallest in dia-
meter.
  After it is invested with the spongy substance it has a
small enlargement, and then  continues nearly of one 
Mucous Ducts of the Urethra.          185
size  until it arrives near the glans penis, when it again
enlarges and alters its form, being no longer cylindrical
but flattened. Its broad surfaces have now a lateral aspect.
  From the bulb of the corpus spongiosum to this last
enlargement, the appearance  of the inner surface of the
urethra is uniform.  The membrane is thin and delicate,
and in a healthy subject, who has been free from disease
of these parts, is of a whitish colour; but bloodvessels are
very perceptible in it. When it is relaxed, it appears to
be thrown into  longitudinal wrinkles; but it admits of
considerable  extension,  being somewhat elastic: when
extended, its surface appears smooth, as if it were cover-
ed with an epithelium.  Throughout the whole  extent of
this part of the  urethra, are the orifices of a great many
mucous ducts or sinuses, which pass obliquely back-
wards from the surface. Many of these  are so small that
they cannot be penetrated by a bristle,  or probe of that
size;  but some are larger. It has  not  been observed that
any  glandular body  immediately surrounds them,  al-
though they secrete the mucus with which  the  urethra
is lubricated.  On the lower side  of the urethra, near the
commencement of the glans  penis, there is  one or more
of them, so large that their orifices sometimes  admit the
point of a small bougie.
   These  organs,  when inflamed,  secrete the puriform
discharge which takes  place in gonorrhoea.  In a natural
state they produce the mucus which is  constantly spread
over the surface of the urethra, to defend it from the acri-
mony of the urine, and which passes away with that fluid
 un perceived.
   The surface of the urethra is endued with great sensi-
bility, and is therefore liable to great  irritation  from con-
tact with any rough  body or any acrid substance.  Irri-
tation, thus excited, induces a state of contraction, which
is particularly remarkable, as no muscular fibres are to
be seen in its structure. When a bougie has been passed
   Vol. II.              2 A 
186        Contractile Power of the Urethra.
into the urethra for a considerable distance, if it cannot
proceed the whole way, it sometimes happens  that the
instrument will be discharged  by a steady uniform  mo-
tion, which seems to proceed  from a progressive con-
traction of the  urethra, beginning very low down.  At
particular times,  after the urethra has been much irritat-
ed, it will not receive a bougie, although at other times
a bougie  of equal size may be passed to  the bladder
without opposition. This cannot depend upon that elas-
ticity which was noticed before.
  Upon the two crura of the penis, or the beginning of the
corpora cavernosa, are fixed the muscles called Erectores
Penis, which are described in the first volume.* These
muscles cover the crura of the  penis from their origin to
their junction, and not  only compress them, but also in-
fluence the motion of the penis when  it is distended.
  The  bulb of the urethra  is covered by a muscular coat,
called  the Accelerator Urina,* which has  the  effect of
driving forwards any fluid  contained in the cavity pf the
urethra, and also of giving the same direction to the blood
in  that part  of the corpus spongiosum. 1 here is  also
the Transversus Perinei on each  side, that passes  trans-
versely  from the tuberosity of the ischium to the bulb of
the  urethra. Finally  the lower part of the sphincter  ani
muscle, which is nearly eliptical  in form,  is inserted by
its anterior point into the muscular covering of  the bulb
of the urethra. Upon removing  the  integuments,  these
muscles are in view; and the course of the urethra from
the  bladder is concealed,  particularly  by the anterior
point  of the sphincter ani.  When the sphincter ani is dis-
sected away from its anterior connections,  and the cel-
lular and  adipose substance, which  is sometimes very
abundant,  is also removed, the  lower  surface of  the

  *  See description of " Muscles about the Male Organs of Gene-
ration," Vol. I. Part II. Chap. II. 
In tegu m ents of the Penis.          187
membranous part  of the urethra may be brought into
view, as it proceeds from the prostate gland to the bulb
of the corpus spongiosum.*
   When the accelerator urinse is removed from the bulb
of the urethra, there will appear two bodies, which have
some resemblance to flattened peas. They lie one on each
side of the urethra, and communicate with its cavity by
means of a duct, which is from one third to half an inch
in length. These are Cowper's glands.
   The  penis is connected to the symphysis  pubis by a
ligamentous substance, which proceeds from the back or
upper surface of the organ to the anterior part  of  the
symphysis,  and connects these parts firmly to each other.
   Thus constructed, of the  corpora cavernosa and  the
urethra with its corpus spongiosum, and attached  to  the
pelvis as above mentioned, the penis is invested with its
integuments in the following manner.


               Integuments of the Penis.
   The  glans penis, the structure of which has been al-
ready desciibed, is covered by a continuation of the skin,
which appears altered in its texture so as to resemble in
some respects the skin of the lips, and in like manner is
covered by a delicate production of cuticle.
   Around the corona of the glans, especially on its upper
ptrt,  there  are whitish tubercles, which are of different
sizes  in different persons, but  always very small.. The
skin adheres firmly to the whole extent of the corona of
the glans,  and is very delicate in its  structure as it con-

  * The  natural situation of the membranous part of  the urethra,
and of the prostate gland, as well as their relative position with
respect to the sphincter ani, rectum, Sec. can be best studied by a la-
teral view of the contents of the pelvis; which is to be  obtained by
removing carefully one of the ossa innominata, and dissecting the
parts which were inclosed by it. 
 188                The Prepuce.

 tinues from the glans upon the body of the penis; but it
 gradually changes, so as to  assume the appearance and
 structure of common  skin, and continues in this  state
 over the penis.  The adhesion of the skin to the ligament-
 ous coat of the corpora cavernosa also  becomes more
 loose, owing to the quantity and texture of the cellular
 substance which connects them.  The  skin thus connect-
 ed to the penis, has commonly more length than that or-
 gan, even in its extended state. In consequence  of this
 greater length, and of its adhering firmly around the co-
 rona glandis, it necessarily forms a circular fold or plait,
 which varies in size according to  the length of the skin.
 This fold is  generally situated at the commencement of
the firm attachment of  the skin to the  body of the penis,
 or around the glans; but it may be formed any where
 upon the body of the penis by artificial management.
  This  duplicature, or fold of the skin, when it takes
 place so as to cover the glans, is called the Prepuce; and
 the skin which  is very tender and delicate for some dis-
 tance from the  glans, forms that surface of the prepuce
 which is in  contact with the glans when it covers that
 body.
  There is also a small fold of the skin, which is longi-
 tudinal in its direction, that commences  at the orifice of
 the urethra,  and extends backwards,  on the lower sur-  ■
 face of  the penis.  It is unvarying  in its  position, and is
 called the Frenum.
   It is a general observation, that adepts is not found in
 the cellular substance which  connects  the  skin to the
 body of the penis; but this cellular substance is distended
 with water in some hydropic cases.
   From the skin immediately below the  glans, and from
 small follicles on each  side of the frenum, is secreted an
 unctuous fluid, which, when allowed to continue, be-
 comes inspissated,  and acquires  a caseous  consistence
 and colour, as well as a peculiar odour.  It  sometimes 
        Bloodvessels and Absorbents of the Penis.   189

also acquires an acrimony which produces inflammation
of the surface with which it is in contact,  as well as the
copious secretion of a puriform fluid.
   The distribution of the pudic artery in the penis, has
already been mentioned; and a further account of its ori-
gin  and progress to its  destination, will be found in the
general account of the arteries. Sometimes small branches
of the external pudic  arteries, which  originate from the
femoral, are extended to the penis; and it has been as-
serted, that branches  of  the middle haemorrhoidal artery
have also been found there, but this  does not often occur.
   The Veins of the penis are  of two kinds: those which
originate in the  corpora  cavernosa,  accompany the  cor-
responding  branches of  the pudic artery, but  communi-
cate more or less with the plexus of veins on the lower
and  lateral part of the bladder.  These is also a great vein
which occupies the groove on the back of the penis, be-
tween the corpora  cavernosa, that appears particularly
appropriated to the corpus spongiosum urethras; for  it
originates in the glans penis, and receives branches from
the urethra as it proceeds backwards. There are often two
of these veins, one in the groove and the other more su-
perficial: they generally unite near the  root of the penis.
The common trunk then passes between the body of the
penis and the symphysis pubis, and terminates in a plexus
of veins at the neck of the bladder, which is connected to
the plexus above mentioned on the lower and lateral parts
of the same viscus.
  The Absorbent Vessels  of the penis take two different
directions on each side.  Those which  arise from the in-
teguments generally, unite so as to  form a few trunks on
the back of the penis, which divide near the root of the
organ, and  proceed to the glands  of  the groin.  Those
which originate from the interior parts of the  penis, ac-
company the bloodvessels,  and terminate in the  plexus
of lymphatics in the pelvis. 
190         Nerves.—General Observations.
   It ought to be noted, that the superficial lymphatics
generally enter the upper inguinal glands.
   The Nerves of the penis are principally derived from
the lower sacral  nerves, which unite in the plexus that
forms  the great ischiatic. From these nerves a branch on
each side originates, which passes, like the pudic artery,
between the sacro-sciatic ligaments. In this course it di-
vides into two branches, one of which passes below to the
muscles of the penis and urethra, and to the contiguous
parts;  and some of its branches seem finally to terminate
in the  dartos:  the  other branch proceeds along the crura
of the  pubis and ischium, and passing between the sym-
physis pubis and the  body of the  penis, arrives at the
upper  surface or dorsum of the penis, along which it con.
tinues  on the outside of the arteries to the glans, in which
it terminates. In this course it sends off several branches,
some of which terminate in the integuments of the penis.

    After an examination of the relative situation of the mus-
       cits and bloodvessels of the male organs of generation*
       there appears reason to doubt, whether the erection of
       the penis can be referred to pressure upon the veins
       which return from that organ.—Albinus has written on
       this subject. See Academicarum Annotationum, lib. ii.
       caput xviii. Haller has also considered it, and stated the
       opinions of  several anatomists, in his Elementa Phy-
       siologiae, torn. vii. page 555.
    The manner in which the urine is confined in the bladder
       does  not appear to be  clearly  understood. The con-
       nexion 'of the neck of the bladder  with the  prostate,
       and the appearance of the contiguous parts of  the blad-
       der, do  not  render it mfobable that these parts act like
       a sphincter.  The late J.  Hunter, who paid great atten-
       tion to the functions of these  organs, was  very decid-
       ed in his opinion that the contraction of the urethra pro-
       duced the effect of a sphincter of the bladder. He has
       published some very ingenious observations respecting
       the manner in which urine is discharged from  the blad- 
General Observations.              191
  der, in his Treatise on the Venereal Disease, part  III.
  chapter IX.
Mr.  Hunter also long since  asserted, that  the  vascular
  convoluted appearance of the corpus spongiosum urethrae
  was more distinct in the horse than the man. In the  fifth
  volume of the Lecons d'Anatomie Comparee of Cuvier,
  the very learned and ingenious author  confirms the de-
  claration of Hunter, respecting the vascular  convolu-
  tions of the corpus spongiosum of the horse. He states,
  that the corpora cavernosa of the penis of the elephant
  appear to be filled in a great degree with the ramifica-
  tions of veins,  which communicate with each  other by
  such large and frequent anastomoses, that they#have a
  cellular appearance.  A similar structure exists  in the
  horse,  camel, bullock, deer, Sec. and in them all these
  communicating branches can be distinguished from those
  which  extend the  whole length of the penis.
The corpus spongiosum urethrae, according to M. Cuvier,
  is constructed in a similar manner. From these facts he
  is induced to  believe that  this structure pervades the
  whole  class of mammalia. 
192
                    CHAPTER VI.

        OF THE FEMALE ORGANS OF GENERATION.

 I HE female organs of generation consist of the Uterus
and  Ovaries, with their appendages; and of the  Vagina,
with  the structure which surrounds its external orifice.
The uterus is situated in the pelvis, between the bladder
and rectum; and the ovaries are on each side of it.  The
vagina is a very large membranous  canal,  which passes
from the uretus downwards and forwards, also between
the bladder and rectum, and opens externally.
   Connected with the orifice of the vagina are several bo-
dies, which are called the external parts of generation,.
in order to distinguish them from the uterus and ovaries,
and their appendages, and also from the canal of the vagi-
na; which  are called the internal parts.
   The bladder  of urine lies above and in contact  with the
vagina:  the urethra  is also intimately connected with it.
The  description of the  bladder and urethra is therefore
placed at the end of this chapter.
                    SECTION I.

        Of the External Parts of Generation.
  The adipose membrane,  immediately anterior to the
symphysis pubis, and on each side of it, form a conside-
rable prominence in females, which,  at the age of puber-
ty, is covered with hair, as in males.   This prominence
is denominated the Mons Veneris. 
Labia Externa.—Clitoris.          193
  The exterior orifice commences immediately below
this. On each side  of this orifice  is a prominence  con-
tinued from the mons veneris, which is largest above, and
gradually diminishes as it  descends.  These prominences
have some hair  upon  them.  They are  called the Labia
Externa. Their junction below is denominated the Four-
chette. The space between the place of their junction and
the anus  is rather more than an inch in extent, and is de-
nominated the Perineum.
   As the skin which forms the labia is  continued inter-
nally, it becomes more thin and soft, and is covered by a
more delicate cuticle. It is also more or less florid, and
secretes a peculiar mucus.
  In the  upper angle, formed by the labia externa, is the
upper extremity  and glans of the clitoris.
  The Clitoris is a body which has a very strong resem-
blance to the penis, but there is no urethra attached to it.
It has two crura  of considerable length,  which originate,
like those of the penis, from the crura  of the  pubis and
ischium, and unite at the symphysis of the pubis so  as to
form a body,  which is not much more  than an inch in
length, and is broad in proportion.  The extremity of this
prgan,  called the Glans of the  Clitoris, forms a small
tubercle, which  is covered above and on the  sides by a
small plait or fold of the skin, denominated the Prepuce.
These parts  are lubricated by a secretion similar to that
which is  observed round the glans penis.  .
  The crura of the  clitoris have muscles similar to the
erectores penis.  The interior structure of the  Clitoris is
very similar to that of the corpora cavernosa of the penis,
or the corpus spongiosum of the urethra. It appears con-
structed for  a similar distention, and is  endued with the
same sensibility  as the penis.  The two  lateral parts are
also separated from each other by a septum, resembling
that of the penis.  It is united to the symphysis pubis by
a ligament.    *
  Vol. II.               2 B 
194              Nympha.—Hymen.

  The Prepuce of the clitoris has a semicircular form:
below its extremities two folds or plaits commence, one
on each side, which are situated  obliquely with respect
to each  other,  so as to form  an  angle. These folds are
denominated the Nympha.
  The Nympha  extend from the clitoris downwards
nearly as far iis the middle of the orifice of the vagina.
They are situated within the external  labia, and  are
formed by the skin after it has become more delicate in
its texture.  Their surface  however is often  somewhat
corrugated.  There are many  bloodvessels in their inter-
nal structure,  and  it is supposed they are occasionally
somewhat tumid. They are flat, and their exterior edge
is convex; so that they are narrow at their extremities,
and broad in the middle.  Their breadth is very variable,
and in some instances is great. In a majority of cases it is
equal to one fourth of their length. Their colour in young
subjects is of a bright red;  in women advanced in years
and who have  had many children, they  are of a brown
red,  and sometimes of a dark colour.
   The use of these parts is not very evident. They have
been supposed to regulate the course of the urine as it
flows from the urethra, but their effect in this respect is
not  great.  They have also been supposed to favour the
necessary enlargement of the parts in parturition.
   The orifice of the urethra is situated about an inch and
one  quarter further inward than the clitoris.  It is often
rather less than the diameter of the urethra, and is some-
what protuberant. The orifices of mucous ducts are to be
perceived around k.
   The orifice of the urethra is at the commencement of
the canal of the vagina.  Immediately within this orifice
is situated the membrane denominated Hymen.
   The Hymen is an incomplete  septum, made by a fold
or duplicature of the membrane  which forms the surface
contiguous to it.  Sometimes it is circular, with an aper- 
The Vagina.
195
ture in the center.  Sometimes it has a resemblance to the
crescent, the aperture being at the upper part of it.  The
hymen has frequently been found without  a perforation,
and has therefore prevented the  discharge  of the men-
strual evacuation. It is generally ruptured in the first in-
tercourse of the sexes; and some small  tubercles, which
are found on the surface of the vagina near the spot where
it was situated, are supposed to be the remains  of it.
These tubercles are called Caruncula Myrtiformes.
                    SECTION II.

                   Of the Vagina.
   THE canal of the vagina, commencing at the hymen
and the orifice of the urethra, is rather more narrow at
its beginning than it is further inward.  From this place it
extends backwards and upwards, and partakes in a small
degree of the curve of the rectum: while the  bladder,
which is above it, and rests upon it,  increases the curva-
ture of the anterior part. It is much larger in women who
have had children than in those who  have not.
   The membrane which lines the vagina resembles, to a
certain degree,  the  membranes which secrete mucus in
different parts of the body. Its surface appears to consist
of very small papilla;; and at the anterior extremity of the
vagina it forms a great number of rugae, which are ar-
ranged in a  transverse direction, both on the part  of the
vagina connected to the bladder, and on that which is
connected to the rectum, while the lateral parts of the va-
gina are smooth. These rugae are most prominent  in the
middle; so that a raised line appears to pass through them
at right angles.  This line extends from without inwards.
The rugae on the part next to the bladder are the strongest. 
196     Corpora Cavernosa.—Sphincter Vagina.

  This arrangement of the surface of the vagina does not
extend beyond the external half of the canal:  on  the  in-
ternal half part, or that nearest the uterus, the surface is
smooth.
  The rugse are considerably diminished in women who
have had children.
  Throughout this surface are to be seen, in  some cases
with the naked  eye, the orifices of mucous follicles or
ducts, which occasionally discharge considerable quanti-
ties of mucus.
  Exterior to this lining membrane of the  vagina is a
dense  cellular structure, which has not yet been com-
pletely investigated:  it is of a lightish colour,  and  has
some resemblance to the texture of the body of  the ute-
rus. It is very vascular, and  appears  to be of a fibrous
structure.  It may be very much distended, and seems
to have a contractile power.
   At the anterior extremity of the vagina, on each  side
of it, there is, superadded to  this,  a cellular or  vascular
substance, from eight lines to an inch in breadth; which,
when cut into, resembles the corpora  cavernosa, or the
corpus spongiosum of the penis. These bodies com-
mence near the body of the clitoris, and extend down-
wards on each side of the vagina.  They have been called
 Plexus Reteformis,  and Corpora Cavernosa  Vagina, and
 are  supposed to be occasionally distended  with blood,
 like the clitoris and penis.
   These corpora cavernosa are covered by  muscular fi-
 bres, which pass over them on each side from the sphinc-
 ter ani to the body of the clitoris; to each of which organs
 they are attached. These fibres constitute the sphincter
 vaginae muscle, and contract the diameter of the vagina
 at the place where they are situated.
   The transversus perinei  muscles also exist in the fe-
 male. They pass from the tuberosities of the ischia, and
 are inserted into a dense whitish substance in the perine- 
Unimpregnated Uterus.             197
um, to which the anterior extremity of the sphincter ani
is likewise attached.
  The vagina is in  contact with the  rectum behind; the
bladder lies upon it and anterior to it.  A small portion of
peritoneum, to be reflected to the  rectum, is continued
from the uterus upon the posterior part of it. The lateral
portions of it are invested with cellular substance.  The
anterior extremity of the uterus,  which is called the Os
Tincae, projects into it from above.
                    SECTION III.

    Of the Uterus, the Ovaries and their Appendages.

                     The Uterus
   HAS been compared to a pear with a long neck. There
 is of course a considerable  difference between the body
 and neck; the first being twice as broad as the last. Each
 of these parts is somewhat flattened.
   In subjects of mature age, who have never been preg-
 nant, the whole of the uterus is about two inches  and a
 half in length, and more than  one inch and a half in breadth
 at the broadest part of the body: it is also near an inch in
 thickness.
   It  is  generally  larger than this in women  who have
 lately had children.
   The uterus is situated in the pelvis between the  blad-
 der and  rectum, and  is inclosed in a duplicature or fold of
 the peritoneum, which forms a loose septum that extends
 from one side of the pelvis to the other, and divides it
 into an  anterior and posterior chamber.  The posterior
 surface of this septum is opposed to the rectum, and the
anterior  to the bladder.  The two portions  of this septum. 
198           Ligaments of the Uterus.
which are between the uterus and the lateral parts of the
pelvis, are called the Broad Ligaments.
  On the posterior surface, the Ovaries are situated on
each side of the uterus, being inclosed by a process of the
ligament or septum. Above them, in the  upper edge  of
the septum, are the Fallopian Tubes, which are ducts that
commence at the upper part of the uterus on  each  side,
and proceed in a lateral direction for some distance, when
they  form an angle and incline downwards to the ovaries.
These ducts are  inclosed between the two laminae of the
septum for the greater part of their length.
  The peritoneum, which forms the  septum,  is reflected
from it, posteriorly, to the rectum and the posterior sur-
face of the pelvis, and anteriorly, to the bladder. In  its
progress, in each direction, it forms small plaits or  folds;
two of which extend from the uterus to the rectum pos-
teriorly, and two more  to the bladder anteriorly:  these
are called the Anterior and Posterior Ligaments of the
Uterus.
  The other ligaments, which proceed more immediately
from the uterus, are called the Round Ligaments. These
arise from each side of the uterus, at a small distance be-
fore and below the origins of the fallopian tubes,  and pro-
ceed in an oblique course to the abdominal rings. These
ligaments are also invested by the peritoneum.  They pass
through the rings and soon terminate.
   In the body of the uterus is a cavity which approaches
to the  triangular form; and from which a canal proceeds
through its neck.  This cavity is so small that  its sides
are almost in contact, and the canal  is in  proportion; so
that  this organ is very thick in proportion to its bulk.
   The substance of which the uterus consists is very firm
and dense: it is of a whitish colour, with a slight tinge of
red. There are many bloodvessels,  with nerves and  ab-
sorbent vessels,  in  its texture.  The nature and structure
of this substance has not yet been precisely  ascertained. 
Structure and Cavity of the Uterus.       199
It appears very different  indeed from muscle;  but the
uterus occasionally contracts, with great force, during la-
bour.  It is not rendered thin by its enlargement during
pregnancy, and the bloodvessels in its texture are greatly
enlarged at that time.
   Exteriorly, the uterus is covered by the peritoneum, as
has  already been mentioned. Internally it is lined with a
delicate membrane that has some resemblance to those
which secrete  mucus,  and  is generally of a whitish co-
lour, abounding with small orifices that can be seen with
a magnifying glass.  This membrane is so intimately con-
nected to the substance of the uterus that some anatomists
have supposed it was merely the internal surface of that
substance, but this opinion  is now generally abandoned.
It is supposed that the colour of this membrane is more
florid about the period of menstruation.
   The cavity of the uterus, as has been observed before,
 is triangular in form.  When the  organ is  in its natural
 position, the upper side of this triangle is transverse with
 respect to the body, and the other sides pass downwards
 and inwards. In each of the upper angles are  the orifices
 of the fallopian tubes, which are of such size  as to admit
 a hog's bristle.
   The two lower lines of the triangle are slightly curved
 outwards at their upper extremities; so that the upper an-
  gles  of the triangle project outwards, and the orifices of
  the fallopian tubes are nearer to the external surface than
  they  otherwise would be.
    The lower angle of the cavity of the uterus is occupied
  by the orifice of the canal, which passes through the neck
  of  the organ; this orifice is from three to four lines in di-
  ameter.  The canal is about an inch in length, and is rather
  wider in the middle than at either end. On  the anterior
  and posterior portions of its surface are many small ridges
  which have an arborescent arrangement, one large ridge
  passing internally from the commencement of the canal, 
200       Structure of the Fallopian Tubes.

from which a number of other ridges go off in a transverse
direction. These ridges extend  nearly the whole length
of the canal.  In the grooves,  between the ridges, are the
orifices of many mucous ducts. There are also on this
surface a number of transparent bodies of  a round form,
equal in bulk to a middle sized grain of sand; the nature
and use of which  is unknown.  They have  been called
Ovula Nabothi, after a physiologist, who published some
speculations respecting their use, about the  commence.
ment of the last century.
   The canal of the neck of the uterus is  very different
from other ducts, for it seems to  be a part of the cavity
to which it leads, and when the cavity of  the uterus be-
comes enlarged in  the progress of pregnancy, this canal
is gradually converted into a part of that cavity.
   The lower extremity of the neck of the uterus is  irre-
gularly convex and tumid. The orifice of the canal in it is
oval, and so situated diat it divides the convex surface of
the neck into  two  portions, which are called  the Lips. . k]
The anterior or upper portion is thicker than the other.
   This extremity of the uterus protrudes into the vagina,
and is commonly called Os Tinea. As the anterior  por-
tion or lip is  larger and more tumid than  the  posterior,
the vagina extends further  beyond the os tincae on the
posterior part than on the anterior.


                The Fallopian Tubes
   Are two canals,  from four to five  inches in length,
which  proceed between the  laminae  of the broad  liga-
ments, from the upper angles of the uterus, in a trans-
verse direction, to  some distance from the uterus, when
they form an angle, and take  a direction downwards to-
wards the ovaries.
   They are formed, for a considerable part  of their extent,
by a substance which resembles that of which the uretus 
Situation of the Ovaries.           201
consists, and are lined by a membrane continued from the
internal membrane of the uterus. Their extremities ap-
pear to be composed of membrane, which is rendered flo-
rid by the bloodvessels in its texture. At the commence-
ment their diameters are extremely small; but they en-
large in their progress. This enlargement  is gradual for
the first half, and afterwards sudden; the enlarged part is
more membranous than the small part, and has a bright
red colour. The large extremity is loose in the cavity of
the pelvis, and is not  invested by the laminae of the broad
ligaments. Near the termination the diameter is often
contracted; after which the membrane which forms the
tube  expands into an open mouth, the margin of which
consists of fringed processes: this margin is also oblique,
as respects the axis of the tube; and the different fringed
processes  are not all  of the same length; but the longest
are in the middle, and the other regularly diminish on each
side of them: these processes constitute the Fimbria of
the fallopian tubes.
   The internal surface of the  large extremities of these
tubes is extremely vascular; and there are  some longitu-
dinal fibres of a red colour to be seen on it.

               The  Round Ligaments,
   Which have already been mentioned, are cords  of a
fibrous structure, with many bloodvessels in them.  They
arise from the  uterus below the origin of the fallopian
tubes, and proceed under the anterior lamina of the broad
ligament to the abdominal rings, through which they pass;
and then the  fibres and vessels  art  expanded upon the
contiguous cellular substance.

                    The Ovaries
   Are two bodies of a flattened oval form; one of which
is situated on each  side of the uterus on the posterior sur-
   Vol. II.               2C 
202   Structure of the Ovaries. Corpora Lutea.

face of the broad ligament, and invested completely by a
process of the posterior lamina,  which forms a coat, and
also a ligament for it.  The size of this organ varies in dif-
ferent subjects, btit  in a majority of those who are about
the age of maturity it is between ten  and twelve  lines in
length. It is connected to the uterus by a small ligament,
or bundle of fibres of the same structure with the round
ligaments, which is  not more than two lines in diameter,
and is included between the  laminae of the broad liga-
ment.
   The process of the broad ligament forms an external
coat to the ovary; within this is the proper coat of the or-
gan, which is a firm membrane. This  membrane is so
firmly connected to the substance of  the ovary which it
incloses,  that it cannot be easily separated from it. The
ovary is  of a whitish colour and soft texture,  and  has
many bloodvessels.  In virgins of mature age it co? fans
from ten to twenty  vesicles, formed  of a delicate .    v
brane, filled with a transparent coagulable fluid. k
of these vesicles are situated so near to the surface o.   .
ovary that they are prominent on its  surface; others  are
near the center. They are very different in size; the largest
being between two  and three lines in diameter, and others
not more than one third of that size.
   In women  who have had children,  or in whom concep-
tion has taken place, some of these vesicles are removed;
and in their place a cicatrix is found.
   It has been ascertained, that during the sexual inter-
course with males,  one of these vesicles, which was pro-
tuberant  on the surface, is often ruptured, and a cavity is
found. A cicatrix is soon formed,  where the membrane
was ruptured; and  in the place occupied by the vesicle
there is a yellow substance denominated Corpus Luteum.
This corpus luteum generally continues until the middle
of pregnancy: it often remains during that state, and for 
Arteries of the Uterus.             203
some time after delivery, but it gradually vanishes.  The
cicatrization continues during life.
   In many cases these  cicatrices correspond  with the
number of conceptions which have taken place; but they
often exceed the  number of conceptions,  and they have
been found in cases where conception has not been known
to have taken place.
   In very old subjects, where conception has never taken
place, the vesicles are either entirely removed, or small
dense tubercles only remain in their place.

                     The Arteries
   Of the uterus are derived  from  two very different
sources; viz. from the spermatic and from the hypogas-
tric arteries.
   The spermatic arteries, instead of passing directly down
to the abdominal ring, proceed between the laminae of the
broad ligament, and send branches to the ovaries, which
may sometimes be traced to the vesicles. They also send
branches to the fallopian tubes and to the uterus. Those
which are on the opposite sides*of the uterus anastomose
with each other,  and also with the branches of the hypo-
gastric arteries. There are also branches of these arteries
in the round ligaments, which  accompany them to their
termination outside of the abdominal ring.
   The principal arteries of the uterus are those derived
from the hypogastric, which sends to each side of it a
considerable branch, called  the Uterine.  This vessel
leaves the hypogastric very near the origin of the internal
pudic, and proceeds to the cervix of the uterus: it passes
between  the lamina? of the broad ligaments, and sends
branches to  the edge of the uterus,  which penetrate its
texture. The branches which  are  in the texture of the
uterus are very small indeed, in young subjects.  In wo-
men who have had children they are considerably larger; 
204       Veins of the Uterus. Lymphatics.

but during pregnancy they gradually enlarge  with the
growth of the uterus, and become very considerable.
These arteries observe a serpentine and peculiarly tor-
tuous course.  Those on the opposite  sides anastomose
with each other.

                      The Veins
   Of the uterus,  like the arteries, form spermatic and
uterine trunks. The Spermatic Vein is much larger than
the artery. It ramifies as in males, and forms a very
large plexus, which constitutes the corpus pampiniforme.
Many of the veins which form this  body, originate near
the ovary: a considerable number also come from the fal-
lopian tubes and the uterus. The spermatic  vein and its
branches are greatly enlarged indeed during pregnancy;
and it is said that they are enlarged the same way during
the menstrual discharge.
   The most important veins of the uterus are the branches
of the Uterine  Veins. They are extremely numerous, and
form a plexus  on the side of the uterus; from which two '  *
or more uterine veins proceed in the course of the artery,
and join the hypogastric. These veins also a^e greatly en-
larged during pregnancy.


               The Lymphatic Vessels
   Of the uterus, and its appendages, are very numerous.
In the unimpregnated state  they  are small; but, during
pregnancy, they increase greatly. They proceed  from the
uterus in very  different directions. Some that accompany
the round  ligaments go to  the lymphatic glands of the
groin.  Others  which take the course  of the uterine blood-
vessels pass to glands in the pelvis, and a third set follow
the spermatic arteries and veins to the glands on the loins. 
Bladder and Urethra.
205
                    The Nerves
  Of the ovaries are derived from the renal plexus, and
those of the uterus and vagina from  the  hypogastric
plexus, or the lower portions of the sympathetic, and the
third and fourth sacral nerves.
                    SECTION III.

             Of the Bladder and Urethra.

  The situation of the Bladder, as respects the symphy-
sis pubis, is nearly  alike in both sexes; but that part of
it which  is immediately behind the insertion of the ure-
ters is rather lower in males than in females.  The bottom
of the bladder rests upon  the upper part of the vagina, a
thin stratum of cellular substance  only intervening:  when
that  viscus is distended it forms a tumor, which  com-
presses the vagina.
  The ureters are inserted, and the urethra commences
in the same part of the bladder, in both sexes.
  The length of the  Urethra is  between  one and two
inches. When the body is in a direct position, it is nearly
horizontal; but it is slightly curved, with its  convexity
downwards. It is immediately above the vagina, and it
passes below the body of the  clitoris.  The external ori-
fice of it  is rather more than an inch within the glans or
head of the clitoris. This orifice is somewhat prominent
in the vagina.
  In  the internal or lining membrane of the urethra there
are many orifices of mucous follicles, and also longitudi-
nal wrinkles, as in the urethra  of males. The diameter of
the female urethra and its orifice in the bladder are greater
than they are  in the male.  For this  reason it has betn 
206
Gradual Change in the Gravid Uterus.
supposed, that  women are less liable to calculus of the
bladder than men.*
   The urethra is intimately connected with the external
coat of the vagina, and between them there is a spongy
cellular   substance which makes the rough surface of the
vagina prominent; so that the urethra has been supposed,
although erroneously, to be invested with the prostate.
It is capable of great artificial dilatation.

Of the Changes induced in the Uterus in the progress of
                     Pregnancy.
   The alteration which takes place in the size of the ute-
rus during pregnancy is truly great. About the conclu-
sion of  that period, instead of the small body above de-
scribed,  which is  almost  solid, the uterus forms an im.
mense sac, which extends from  the termination of the
vagina in the pelvis, into the epigastric region;, and from
one  side of the abdomen to the other;, preserving, how-
ever, an ovoid  figure.                           >f
   This change is so gradual at first, thai*the uterus doeij  ,
not extend beyond the cavity of the pefvis before the third
month,  although at the end of the  seventh month it is very
near the epigastric* region.     *      ,
   For the first six months the body of the uterus appears
principally concerned in the enlargement:  after "this the
cervix begins to change, a.$d is gradually altered, so as to
compose a portion of the sac, rather of less thickness than
the rest of the uterus; the mouth being ultimately an aper-
ture in a part which is much thinner than  the other por-
tions of the organ.      *
   The change which takes place in the texture of some
of the appendages of the uterus is very important.
   The  Broad Ligaments, which seem particularly calcu-
lated to favor the extension of the uterus,  are necessarily
   * It has however been asserted that they are also less liable te
  alculi in the kidneys. 
General Observations.
207
 altered by the change in the size of that organ, but not en-
 tirely  done away. The portion of peritoneum of which
 they are  formed must be very much enlarged with the
 growth of the uterus, as  it continues to cover it.  The
 Round Ligaments are much elongated; and they observe
 a more straight course to the abdominal ring. The Fallo-
 pian Tubes are enlarged; and instead of passing off late-
 rally from  the uterus, they now proceed downwards by
 the side of it. The Ovaries appear rather larger and more
 spongy: their relative situation is necessarily lower.
    The change in the Uterus itself is particularly  interest-
 ing. The great increase of its size is not  attended with
 any considerable diminution  of thickness  in  its  sub-
 stance; nor are the arteries much less convoluted than be-
 fore pregnancy, as might have been expected. They are
 greatly" enlarged in diameter, and the orifices of the exha-
 lent vessels on the internal surface of the uterus are much
 'more perceptible.  ,
[  ' The veins are much more  enlarged than the arteries,
'^nd in some places appear more than  half an  inch in dia-
 meter. They are not regularly cylindrical, but rather flat.
 They anastomose so as ton form an irregilar net  work.
    The uterus appears rr)uch more fityous  and muscular
 in the gravid than in the unimpregnated state. The con-
 tractile power of the gravid uterus is not <jnly proved by
 the expulsion of its contents,  but $sq by  veYy vigorous
 contractions, which are occasionally qbseryed by accou-
 cheurs.
                           •       »         •
     Although the general  effect*- which Result from the par-
       ticular conditions of the uterus in pregnane^, menstru-
       ation, &c. evince that the  influence of this organ upon
       the whole system is  very great, yet it seems probable
       that  the sexual peculiarities of females are especially
       dependent upon the ovaria.
          This sentiment is confirmed by an  account of a wo-
       man in whom the ovaria were deficient, whick is pub- 
208     Peculiarity of the Female Hottentots.
       lished in the  London Philosophical Transactions for
       1805, by Mr. C. Pears. The subject lived to the age of
       twenty-nine years. She ceased to grow after the age of
       ten years, and therefore  was not  more  than four feet
       six inches in height:  her breadth across the hips was
       but nine inches,  although the breadth of the shoulders
       was fourteen. Her breasts and nipples  never enlarged
       more than they  are in the  male  subject. There was
       no hair on the pubes, nor  were there any indications of
       puberty in mind  or body.  She  never menstruated. At
       the age  of twenty-nine she died of a complaint in the
       breast, attended  with  convulsions: The uterus  and os
       tincae were found not increased beyond their usual size
       during  infancy.  The  cavity of the uterus  was of the
       common  shape, but its coats were membranous. The
       Fallopian Tubes  were  pervious. " The  Ovaria were so
       indistinct that they rather showed the rudiments which
       ought to have formed them, than any part of the natural
       structure."
    Another case,  which confirms the  aforesaid sentiment,
       is related in one  of the French periodical publications.
         It has been long known  that a race of savages near the
       Cape of Good Hope were distinguished from the gene-
       rality of their species by a peculiarity about the puden-
       dum. An account of this structure has been given with
       some precision by  Messrs.  Peron and  Lesueur, in a
       paper which was read to the National Institute of France.
       It is  a flap or apron, four inches  in length, which is
       united to the external labia near their upper angle, and
       hangs down before the clitoris and the  external orifice
       of the parts of generation. It is divided below into two
       lobes, which cover the orifice.  It is formed by a soft
       distensible skin,  free from hair, which is  occasionally
       corrugated like  the scrotum, and  is rather more florid
       than the ordinary cutis.*

  * This paper has not yet been  published by the Institute, but it is
referred to by M. Cuvier in his Le$ons d'Anatomie Comparee,
vol. v. page 124.—Messrs. Peron and Lesueur were naturalists who
accompanied captain Baudin in bis voyage of discovery. 
Peculiarities in the Abdomen of the Foetus.
209
             The Abdomen of the Foetus.
   The difference between the foetus and the adult, in the
cavity of the abdomen,  is very conspicuous at the first
view.
   The  Liver in the foetus is so large that it occupies a
very considerable part of the abdomen. Its left lobe, which
is larger in proportion than the right, extends far into the
left hypochondriac region.
   The  Bladder of urine, when filled, extends from the
cavity of the pelvis a considerable distance towards the
umbilicus; so that the greatest part of it is in the cavity
of the abdomen. A ligament of a  conical figure extends
from the center of the upper part  of  the  bladder to the
umbilicus; with  an artery on each side of it, which is soon
to be described.  This ligament, which is in the situation
of the urachusof the foetus of quadrupeds,  is hollow, and
thus  frequently  forms a canal, which has a  very small
diameter, that communicates with the bladder by an aper-
ture still smaller, and continues a short distance from die
bladder towards  the umbilicus. In a  few rare instances
this canal has extended to the umbilicus, so that urine has
been discharged  through it, but the ligament is commonly
solid there.
   The  Stomach appears to be more curved in tire foetus
than in  the adult.
   The Great Intestine does not extend sufficiently far, be-
yond the insertion of the ileon, toforrri*the caecum com-
pletely.
   The  Glandula Renales are much larger in  proportion
in the foetus than in the  adult. The colour of the fluid
they contain is more florid.
   The  Kidneys are lobulated.
   The  Testicles in the foetus are found above the pelvis,
in the lumbar region,  behind the  peritoneum, until two
   Vol. II.              2  D 
210      Descent of the Testicle in the Foetus.
 months before birth. Thus situated, their bloodvessels and
 nerves proceed from sources which are near them; but the
 vas deferens,  being  connected to the  vesicular seminales
 by one extremity, is necessarily in a very different situa-
 tion from what it is  in the adult: it proceeds from the tes-
 ticle downwards to the neck of the bladder.—While each
 testicle is in this situation, it  is  connected with a sub-
 stance or ligament,  called  Gubernaculum, of a conical or
 pyramidical form, attached  to its lower end, and extends
 from it to the abdominal ring. This substance is vas-
 cular, and of a fibrous texture: its large extremity ad.
 hcres  to  the  testicle,  its lower and  small  extremity
 passes  through the abdominal ring, and appears to ter-
 minate in  the cellular substance exterior to  that  open-
 ing, like the  round ligament in females.  The Guber-
 naculum, as well as the testicle,  is behind the peritoneum;
 and the peritoneum adheres to each of them more  firmly
 than it  does to any  of the  surrounding parts.  It  seems
 that, by the contraction of the Gubernaculum, the testicle
 is moved down from its  original situation to the abdo-
 minal  ring,  and through the  abdominal ring into the
 serotum.  The peritoneum, which adheres firmly  to the
 gubernaculum and  testicle, and  is loosely connected to
. the other parts, yields to this operation; and when the tes-
 ticle has arrived near the abdominal ring, a portion of the
 peritoneum is protruded a little  way before it into the
 scrotum; forming a cavity like the finger of a glove. The
 testicle passes down behind this process of the peritoneum,
 and is covered by it as it was in the abdomen. Although
 it appears  protruded into  the cavity,  it  is exterior to it,
 and behind  it; and  the  vessels, &c. which belong to the
 testicle are also exterior to  it.
    The cavity formed  in the scrotum, by this process  of
 the peritoneum, necessarily communicates with the cavity
 of the abdomen at its formation; but  very  soon after the
 testicle has descended into the scrotum, the upper  part of 
Umbilical Vessels.                211
this cavity is closed up, while the lower part of the pro-
cess continues  unchanged,  and  constitutes the Tunica
Vaginalis Testis. In some instances the  upper part of this
process does not close up, and the communication  with
the cavity of the abdomen continues. The descent of the
intestine into the cavity thus circumstanced,  constitutes
that species of hernia which is denominated Congenital.*
   The most important peculiarities in  the abdomen of
the foetus are those connected with  the  circulation of the
blood.
   The internal iliac or hypogastric arteries are larger than
the external iliacs.  Their main trunks are  continued on
each side of the bladder to its fundus; and proceed from
it, with the ligament,  to the  umbilicus; when they pas6
out of the abdomen to  go along the  umbilical cord to the
placenta. These  arteries are now denominated the Umbili-
cal,  and are very considerable in  size.  After birth,  as
there is no circulation in them, they soon begin to change:
the cavity of them is  gradually obliterated, and they are
converted into ligaments.  They are exterior  to the peri-
toneum, and contained in a duplicature of it.
   A vein also called the Umbilical,  which is much larger

  * These interesting circumstances respecting the original situa-
tion of  the testicle, and its descent into the scrotum, were disco-
vered and elucidated by Mailer, Hunter, Pott, Camper, and several
other very respectable anatomists and surgeons. There is however
a difference of opinion, between some of them, as to the time when
the testicle leaves the abdomen.  Haller thought the testicles were
seldom  in the scrotum at birth. Hunter and Camper found them so
generally.
  It has been suggested that there are some national peculiarities in
this respect; that amongst  the Hungarians, for example, the testi-
cles  often remain above the abdominal ring until near the age of
puberty.
  The student will find.an interesting description of the situation of
the testis, and its descent, in the foetus, in the " Observations on
certain parts of the  Animal Economy." by John Hunter. 
212                Ductus Venosus.
 in diameter than both of the arteries,  returns from the
 placenta along the cord,  and enters the cavity of the ab-
 domen at the umbilicus. It proceeds  thence,  exterior to
 the peritoneum, but in a duplicature of it called the Fal-
 ciform  Ligament, to the liver, and enters that viscus at
 the great fissure; along which it passes  to the left branch
 of the sinus of the vena portarum, into which it opens and
 discharges the blood  which flows through it from the
 placenta. It opens on the  anterior side of the  branch of the
 vena portarum, and from the posterior side of the branch,
 opposite to this opening, proceeds a duct or canal, which
 opens into the left hepatic vein near its junction with the
 vena cava. This communicating vessel is called the Due-
 tus,  or  Canalis Venosus;  to  distinguish it from the  duct
 which passes from the pulmonary artery to the aorta, and
 is called Ductus, or Canalis Arteriosus. This venous  duct
 carries some of the blood of the umbilical vein directly to
 the vena cava; but it is  much smaller than  the umbilical
 vein, and of course a considerable quantity of the blood
 which passes through the umbilical vein must pass through
 the liver, by the  vena portarum,  before it can enter the
 cava.
   In some foetal subjects, if a probe of sufficient length be
 introduced within the umbilical vein and pushed forwards,
 it will pass to  the heart without much difficulty or oppo-
 sition, as if it proceeded along one continued tube, al-
 though  it really passes from the umbilical  vein across the
 branch of the vena portarum, and then through the ductus
 venosus, and through a portion  of the  left  hepatic vein,
 into  the inferior ve .a cava.
   If the umbilical vein be injected with a  composition,
 which will be firm when  cool, it appears to terminate in a
rounded end, which is situated in  the  transverse  fissure
of the liver: the sinus of  the vena portarum,  into  which
this  vein enters,  appears like two  branches going off,
one lrom each side of it,  and the ductus venosus like 
       Object of the Circulation in the Placenta.     213
 a  branch continuing in the direction of the main trunk
 of the umbilical vein.
   The umbilical vein, in its progress through the fissure
 of the liver, before it arrives at the sinus of the vena por-
 tarum, sends off a considerable  number of branches to
 each of the lobes of that organ, but more to the left than
 to the right lobe.
   After birth,  when blood ceases to flow through the um-
 bilical vein, it is gradually converted into a ligament;  and
 the  venous duct is also converted into a ligament  in the
 same manner.  The vena portarum, which before appeared
 very small, when compared with the umbilical vein, now
 brings all the blood which fills its great sjnus, and increases
 considerably in size.
   It has been ascertained  by anatomical  investigation,
 that the umbilical arteries above mentioned, after ramify-
 ing minutely  in the  placenta,  communicate with the mi-
 nute branches  of the umbilical vein; and it is probable that
 the whole blood carried to the placenta by these arteries,
i returns by the umbilical vein to the foetus.
   It is clearly proved by die effects of pressure on the
 umbilical cord, in cases of delivery by the feet, as well as
 by other similar circumstances, that this circulation  civi-
 not be suspended for any length of time without destroy-
 ing  the life of the foetus.  From these circumstances, and
 from the florid colour which the blood acquires by circu-
 lating in the placenta, it seems probable that the object of
 the  circulation through that organ is somewhat analogous
 to the object of the pulmonary  circulation  through the
 lungs of adults.*

   * During the first four months of pregnancy a very small vesicle,
 which does not exceed the size of a pea, is found between the chorion
 and the amnios, near the insertion of the umbilical cord into the pla-
 centa. It is connected to the fcetus by an artery and a vein, which
 pass from the abdomen through  the  umbilicus,  and proceeding
 along the cord to the placenta, continue from it to the vesicle. The 
 214      Object of the Circulation in the Placenta.

 artery arises from the mesenteric, and the vein is united to the me*
 senteric branch of the vena portarum. It is probable that these ves-
 sels commonly exist no longer than the vesicle,  viz. about four
 months; but they have  been seen by Haller and Chaussier  at th«
 termination  of  pregnancy.  They are  called Omfihalo  Mesenteric
 vessels. The vesicle is denominated the Umbilical Vesicle.
  This  inexplicable structure  is delineated in  Hunter's Anatomy
 of the Gravid Uterus, plate xxxiii. figures v. and vi.; in the Aca-
demical Annotations of Albinus,  first book, plate  i. figure xii.;
and also in the  Icones Embryonum Humanoriyn  of Soemmering,
figure ii. 
SYSTEM OF  ANATOMY.
PART  IX.
             OF THE  BLOODVESSELS.

THE  Bloodvessels are flexible  tubes, of  a peculiar
texture, through which blood passes from the heart to
the different parts of the body,  and returns again from
these parts to the heart. They are to be found, in varying
proportions, in almost every part of the body, and seem
to enter into its texture.
   The tubes, which carry blood from the heart, are more
substantial and more elastic than those through which it
returns  to  the heart.  They are  generally found  empty
after death; and, therefore,  were called Arteries by the
ancient anatomists, who supposed that  they  carried air,
and not blood.
   The  tubes which return  the  blood  to the heart are
denominated  Vjeins. They  are less substantial and less
elastic than arteries, and are generally full of blood in the
dead subject.
   There are two great arteries, from which all the other
arterial vessels of the  body are 'derived. They are very
justly compared to the trunks of trees, and  the smaller
vessels  to their branches. One of these great arteries, 
216          The Bloodvessels in general.
called the Aorta, carries blood to every part of the body.
The other  great vessel,  called the Pulmonary Artery,
carries blood exclusively to the lungs.
  The veins which  correspond to the branches  of the
Aorta, unite to each other, so as to form two great trunks
that proceed to the heart. One of  these trunks, coming
from the superior parts of the body, is called tho Superior,
or Descending Vena Cava. The other, which  comes from
the lower parts of the body,  is called the  Inferior, or
Ascending Vena Cava.
  The veins which  correspond with the branches of the
Pulmonary Artery, and return to the heart the blood of
the lungs, are four in number: two of  them proceeding
from each lung. They are called Pulmonary Veins.
  In many of the veins there  are valves, which prevent
the blood they contain from  moving towards the surface
and extremities of the body, but allow it to pass towards
the heart without impediment.
  From the construction of the cavities of the heart, and
the position of the valves which are in them; as well as the
situation  of the valves at the commencement  of the great
arteries, and the above mentioned valves of the veins, it is
evident, that when the blood circulates, it must move from
the heart, through the aorta and its branches, to the differ-
ent parts  of the body, and return from these parts through
the venae cava;  to the heart;  that, when deposited  in the
heart by the venae cavae, it must proceed through the pul-
monary artery to the lungs, and  return from the lungs
through  the pulmonary veins  to  the heart,  in  order to
pass again from that  organ into the aorta.
  It is also certain,  that the  blood is  forced from the
heart into the arteries, by the contraction of the muscular
fibres of which the heart is composed; and that the blood-
vessels likewise perform a part  in the circulation,  they
propelling the blood which is thus thrown into them: but
their action appears to depend  upon causes of a complex
nature. 
217
                    CHAPTER I.

 OF THE GENERAL STRUCTURE AND ARRANGEMENT OF THE
                    BLOODVESSELS.

                     SECTION I.

                   Of the Arteries.

THE arteries are so much concerned in the important
function Of the circulation of the blood, that every cir-
cumstance connected  with them is very interesting.
  They are composed of coats or tunics, which are very
elastic and strong, and which are also very thick. In con-
sequence of the  firmness  of  their  coats, they continue
open, after their contents are discharged, like hard tubes.
They submit to  great dilatation, and  elongation, when
fluids are  forced  into them, and return to their  former
dimensions when the distending cause is withdrawn. This
elasticity is particularly subservient to the  circulation of
the blood. It  admits  the  artery to distend  readily, and
receive the blood which is thrown into it by the contrac-
tion of the heart.  It also produces the contraction of the
artery; which  takes place  as  soon  as  the action of the
heart  ceases; and this contraction of the artery necessarily
forces the blood forward,  as the valves at  its orifice pre-
vent it from returning to the heart.
  The motion of the artery, which is so easily perceived
by the touch, and in  many instances also by the eye, is
completely explained  by the discharge of blood into the
artery from the heart,  and by the elasticity of the vessel,
by which it reacts upon the blood. In some cases it is not
  Vol. II.                2 E 
                                               \
218            Structure of the Arteries.

simply the diameter of the artery which is enlarged, but
a portion of the vessel is elongated; and this elongation,
by producing a curvature of it, renders its motion more
visible.
  In the aorta, and probably in its large branches, Elastic
city seems to be the principal cause of the continuance of
the motion which is originally given  to the blood by the
heart. But there are many circumstances connected with
the smaller vessels, which evince that they exert a power
which is very different indeed from elasticity. Thus the
application of local stimulants or rubefacients,  and of
heat,  is followed by an increase of motion in the arteries
of the parts  to which they are applied.  Neither  of these
causes could  produce their effect by the influence of
elasticity: but the effect   of these  and other  similar
causes is uniformly  produced; and a power  of inde-
pendent  motion,  or Irritability, is thus proved to  exist
in these  vessels,  and  seems essentially necessary to the
circulation of the blood.


             The Structure of the Arteries
   Is, therefore, a subject of importance, and has  received.
a considerable degree of attention from anatomists.
   They  are composed of a dense elastic  substance, of
a whitish colour. Their external  surface is rough, and
intimately connected with the cellular  membrane, which
every where surrounds it  in varying  quantities. Inter-
nally, they are lined with a thin membrane, which is very
smooth and flexible, and is also very  elastic.  The  sub-
stance which composes the artery, and is situated between
the cellular investment and the internal membrane, con-
sists of fibres, which  are nearly, though not completely,
circular, but so arranged as to constitute a cylinder* These
fibres may be separated from  each other so as to  form
lamina;,  which have been considered as different coats of 
              Structure of the Arteries.            219
the arteries; but there is no arrangement of them which
composes regular distinct strata. The coats of arteries
may, therefore,  be separated into a greater or smaller
number of laminas,  according to the thickness of these
laminae.
   The fibres which  compose these laminae appear to be
united to each other in a way which  readily allows  of
their separation, at the  same  time that they form a firm
texture. Although arteries thus appear essentially different
from muscles in their  hardness and their elasticity,  as
well as in their general texture,  they are considered, by
a  great majority of anatomists, as partaking more or less
of a  muscular structure.
   In the human subject their structure is very difficult of
demonstration, and great differences exist in the accounts
which are given of it, even by anatomists, who agree in the
general sentiment that the arteries are muscular.
   Thus Haller believed that  muscular  fibres were most
abundant in  the large arteries, while J. Hunter  thought
the reverse.
   Hunter appears to have investigated this subject  with
great attention, and supposed  the muscular substance, in
the composition of arteries, to be interior,  and the elastic
matter exterior; that in  large  arteries this muscular sub-
stance is very small  in  quantity, and gradually increases
in proportion as the artery diminishes in size. He however
observes, that he never could discover the direction of the
muscular fibres. *
   When the great talents of Mr. Hunter, as an anatomist,
are considered, this circumstance cannot fail to  excite a
belief that the existence of these fibres is not certain: and
if to this be added the  fact,  that even  the red coloured
substance of the arteries is elastic, and in that respect dif-
ferent from muscular substance, the reasons for doubt-
ing must be increased.

  * Treatise on the Blood, &c. Vol. I. p. 113. Bradford's edition. 
220  Question respecting the muscularity of Arteries,

   Bichat appears to have entertained  very strong doubts
on the subject;  but he  stands  almost alone; for a large
number  both of  the preceding and  cotemporary anato-
mists, seem to have adopted the sentiment, that the arte-
ries  have a muscular structure.
   The student of anatomy can very  easily examine this -
subject himself, by separating the coats of arteries into dif-
ferent laminae; and by viewing the edges of the transverse
and  longitudinal sections  of those vessels. While thus
engaged with this question, he will read with great advan-
tage what has been written upon it by Mr. Hunter, in his
Treatise on the Blood,  &c. See chapter second, section 3,
Bichat ought also  to be read upon this subject, which he
has discusstd in his Anatomie Generale—System Vascu-
lare a Sang Rouge, article Troisieme, he. and also in his
Traite des Membranes, article Sixieme.
   The belief of the irritability of arteries does not, how-
ever, rest upon the appearance of their fibres.
   1. It is asserted by very respectable authors-,* that they
have been  made to contract by  the application of mecha-
nical and of chemical irritation, and  also of the electric
and galvanic power.
   2. A   partial or  local action of arteries  is  often  pro-
duced by the local application of heat and rubefacients, as
has been already observed.
   3. Arterial  action  is often suspended in a  particular
part by the application of cold. It has also been observed
that the arteries have for a short time ceased  to pulsate
in  cases of extreme  contusion  and laceration of  the
limbs, f

   * See Soemmering on the structure of the Human Body, Vol. IV.
German edition. Dr  Jones on the Process employed by nature for
suppressing Hemorrhage,  &c.
   t This local suspension of arterial motion by cold, &c, applied
locally, is very difficult to explain;  as the action of the heart and the
elasticity of the arteries appear sufficient to account for the pulsation
of the large arteries. 
       Proofs-of the Irritability of the Arteries.     221

  4. When arteries are divided transversely  in living
animals, they often contract so as to close completely the
orifice made by the division.
  5. In a horse bled to death, it was ascertained by Mr.
Hunter,  that the  transverse  diameter of  the  arteries
was diminished to a degree that could not  be explained
by  their elasticity. He  also found that,  after death,  the
arteries, especially those of the smaller size, are generally
in a state of contraction, which is greater than can be
explained by  their elasticity: for if they are distended
mechanically, they do not  contract again to their former
size, but continue of  a larger diameter than they were
before the distention; although their elasticity may act so
as to restore a very considerable degree of the contraction
observed at death.
   The contraction, which is  thus done  away by disten-
tion, Mr. Hunter  supposed  to have been produced by
muscular fibres: for, if it had been dependent on  elastici-
ty, it must have reappeared  when the distending power
was withdrawn.
  It therefore seems  certain, that the arteries  have  a
power of contraction  different from that which depends
upon elasticity: but whether this depends upon muscular
fibres  superadded to  them,  or upon an irritable quality
in the  ordinary elastic fibres of bloodvessels, is a question
which is not perhaps completely decided.
   The motion of the blood in the arteries appears to
depend,
   1st, Upon  the impulse  given to it by the  action of
the heart.
   2dly, Upon the elasticity of the arteries, in consequence
of which they first give way to  the blood impelled  into
them,  and then react upon  it; and
   3dly, Upon the power of contraction in the arteries, or
their irritability.
   In the larger  arteries the blood seems to move as  it 
 222      General Observations on the Arteries.

 would through an inanimate elastic tube, in Gonsequencc
 of the impulse given by the heart, and kept up by the
 arteries themselves. In the smaller vessels it seems pro-
 bable that the  motion of the blood depends in a consi-
 derable degree  upon the contraction which arises from
 their irritability.
   The obvious effect of the elasticity of the arteries is to
 resist distention and elongation, and to contract the artery
 to its natural  state, when the  distending or elongating
 cause ceases to act. But it must also resist the contraction
 induced by  the muscular fibres, and restore the artery to
 its natural size when the muscular fibres cease to act after
 contracting it, as has been observed by Mr.  Hunter.
   It seems probable that all the fibres of which the artery
 consists  are nearly but not completely circular;  for it
 is not certain that  there are any longitudinal fibres in the
 structure of an artery.
   The internal coat of these vessels is very smooth, but
 extremely dense and firm; and seems to  be rendered
 moist  and flexible by an  exudation on  its surface. It
adheres very closely to the contiguous fibres of the coat
 exterior to it,  but may be  very readily peeled off from
 them.  It is of a whitish colour, and,  like the  fibrous
 structure  of the artery, is very elastic. Like that sub-
 stance also it is easily torn or broken, and, when ligatures
 have been applied to arteries, it has been often observed
 that the fibrous structure and the internal coat have been
 separated, while this external cellular coat has remained
 e/itire.
   The arteries are supplied with their  proper blood-
 vessels and lymphatics. It is to be observed, that the
 bloodvessels are not derived from the artery on  which
 they run, but from the contiguous vessels.
   These vessels have nerves also, which are rather small
 in size,  when compared  with those  which go to  other
 parts. 
         General Observations on the Arteries.      223

  Arteries appear to have a cylindrical form, for no di-
minution  of diameter is observable  in those portions of
them which send off no  ramifications.
  When  an  artery  ramifies, the area of  the different
branches  exceeds  considerably that  of the  main trunk.
Upon  this principle the  aorta  and its  branches have
been compared to  a  cone, the basis of which is formed
by the branches, and the apex of the trunk.
  The transverse section of an artery is circular.
  There are no valves in the arteries, except those of the
orifices of the aorta and the pulmonary artery, at the heart.
The valves of the pulmonary artery have  been described
in the 53d page of this volume, and those  of  the aorta
have an  exact  resemblance to  them,  but are rather
larger.
  The course of the arteries throughout  the body is  ob-
viously calculated to prevent their exposure  to pressure,
or to great extension  from the flexure of the articulations
by which they pass.  With this view they sometimes pro-
ceed in a  winding  direction; and  when  they pass over
parts which are  subject to  great distention  or enlarge-
ment, as the cheeks,  they often  meander; and, therefore,
their length may be  increased by straightening,  without
stretching them.
  Their course appears  sometimes to have been calcula-
ted to  lessen the force  of the blood, as is the case with
the  Internal Carotid  and the Vertebral arteries.
  In the trunk of the body the branches  of arteries gen-
erally form obtuse  angles  with  the trunks from which
they proceed.  In the limbs these angles are acute.
  The communication  of arteries with each  other is
termed Anastomosis. In some  instances,  two  branches
which  proceed in  a course  nearly similar,  unite with
an acute  angle, and form  one  common trunk.  Some-
times,  a  transverse  branch  runs  from one to the other,
so as to form a right angle with each.  In  other cases, 
224       General Observations on the Veins.

the two anastamosing branches form an arch, or portion
of a circle, from which many branches go off.
   By successive  ramifications, arteries gradually dimi-
nish  in size, until they are finally extremely small.
   The smallest arteries do not carry red  blood,  their
diameters being  smaller than those of the red  particles
of that fluid: the serous or aqueous part of the blood can,
therefore, only pass through them.
   Many of the arteries which carry red blood, and of the
last  mentioned serous arteries terminate in veins, which
are, in some respects, a continuation of the tube reflected
backwards.
   They likewise terminate in exhalent vessels, which open
upon the external surface, and upon the various internal
surfaces of the body.  The secretory vessels of glands are
likewise the termination of many atteries.
                    SECTION II.

                    Of the Veins.
  THESE  tubes, which return to the  heart the blood
carried from it by the arteries, are more numerous than
the arteries, and often are larger in diameter.
  They generally accompany the arteries, and very often
two veins are found with one artery.
  In addition  to these last mentioned veins, which may
be called deep-seated, there are many subcutaneous veins
which appear on almost every part of the surface of the
body.
  The capacity of all the veins is therefore much greater
than that of all the arteries.
  Those subcutaneous  veins, which are of considerable 
Coats of Veins.
225
size, communicate very freely with each  other, and also
with the deep-seated veins.
  The  trunks  of the veins,  in  those  places  where no
branches  go off,  are generally  cylindrical.  There  are
however some exceptions, in which these vessels are irre-
gularly  dilated, as sometimes  happens in the case of the
internal jugular vein. It is, however, not easy to determine
from the appearance of veins injected after death, respect-
ing their situation during life, as their  coats are very
yielding; and it is very probable that they are, therefore,
preternaturally dilated by the injection.
  Veins, directly or  indirectly, originate from the termi-
nation of arteries: but they do not pulsate as the arteries
do, because the  impulse given to the blood by the heart
is very  much diminished  in  consequence  of the great
diminution of the size of  the vessels  through which  the
blood has passed.
  In  some  cases, however,  when  blood flows from an
opened  vein; the extent of its  projection is alternately
increased and diminished, in quick succession, as if it were
influenced by the pulsation of the heart.
  The  Coats of Veins differ considerably from those of
Arteries,—for they are thinner, and  so much  less firm,
that veins, unlike arteries, collapse when they are empty.
  They consist of a  dense elastic substance, the fibres of
which are much less distinct than  those of arteries,  but
some of them are to be seen in  a longitudinal direction.
These fibres can be made to contract by local irritation;
for  if a vein be laid bare in  a living animal, and then
punctured,  it will  often contract so as to diminish its
diameter very considerably, although no blood  shall have
escaped from the punctures.
  Next to the elastic substance is the internal coat, which
is smooth and polished. It is separated from the substance
exterior to it with difficulty, although it may be taken from
it very easily in the  vena cava.
  Vol. II.                2 F 
226
Colour of the Blood in the Veins.
   This internal coat is more distendible than the internal
coat of arteries, and is not, like the latter, disposed to os-
sification. It is frequently so arranged as to form valves,
which are plaits or folds, of a semilunar form, that project
from the surfaces into the cavities of these vessels.
   Two of these valves are generally placed opposite to
each other; and, when raised up, .hey form a septum
in the cylindrical cavity of the vessel. The septum, thus
composed, is concave  towards the heart.
   The valves have a great effect in preventing the contents
of the veins from  moving in a retrograde  course: they,
therefore, necessarily modify the effects of lateral pressure,
in such a manner, that it propels  the blood forward,  or
to the heart.
   These valves are generally found  in the veins of the
muscular parts  of  the body,  especially in those of the
extremities. They are  not found in those veins which are
in the cavities of the body, nor in the  internal jugulars.—
They are placed at unequal  distances from each other.
   The coats of the veins are somewhat transparent; and,
therefore, those veins  which  are subcutaneous have  a
bluish aspect, which is derived from the  colour of the
blood they contain.
   The colour of the blood in  the veins is  different from
that in the arteries,  being of a  darker  red.
   The situation and arrangement of  the large trunks  of
veins is much alike in different  subjects; but the branches,
especially those which are subcutaneous, are very variable
in their situations. 
227
                     CHAPTER II

   A PARTICULAR ACCOUNT OF THE DISTRIBUTION OF THK
                       ARTERIES.

                      SECTION I.

                   Of the AORTA,

      Or the Great Trunk of the  Arterial System.

 WHEN the heart is in  its natural position, the  right
 ventricle is nearly anterior to the left; and, therefore, the
 AORTA, where it originates from the left ventricle, is
 behind the pulmonary artery, and covered by it. Its first
 direction is  so oblique towards the right side of the body,
 that it crosses the pulmonary artery  behind, and appears
 on the right side of it. It has scarcely assumed this posi-
 tion before its course alters, for it then proceeds obliquely
 backwards,  and to the left;  so as to form a large curve
 or arch, which extends to  the left  of  the spine.
   The  position of  this curve or arch is so oblique, with
 respect to the bod}-, that the cord or  diameter of it, if it
 were extended anteriorly and posteriorly, would strike the
 cartilage of the  second or  third right rib about the mid-
 dle of its length, and the lejt rib near the head. In conse-
 quence of this position of the curve, the AORTA crosses
 over the right branch of the  pulmonary artery, and the
 left branch of the windpipe: and assumes a situation, in
 front, and to  the left of the third dorsal vertebra:  from
 this situation it proceeds downwards; in front, but rather
on the left side of the spine, and in contact with that co-
lumn. 
228   Situation of the Aorta in the Thorax and Abdomen.

  The AORTA, as well as the Pulmonary Artery, for a
small distance  from the heart, is invested by the  peri-
cardium;  and,  when that sac is opened, appears to be
contained in it.
  After  crossing  the  right  branch of  the  Pulmonary
Artery, a  ligament is inserted into it, which proceeds
from the main trunk of  the pulmonary artery at its divi-
sion:  this  ligament  was the  Canalis  Arteriosus in the
foetus.
  As the AORTA proceeds down the spine, it is situa-
ted between the two laminae  of the mediastinum, and in
contact with  the left lamina,  through which it may be
seen. It descends between the crura of the diaphragm, in
a vacuity which is sufficiently large to admit of its pas-
sage without pressure from the surrounding parts, and is
still in contact with the  anterior surface of the spine, but
rather to the  left of the middle of it. It continues this
course along the spine until it arrives at the cartilaginous
substance between the fourth and fifth lumbar vertebrae,
when it  divides into two great branches of  equal size,
which form an acute angle with each other. These are de-
nominated the  COMMON,  or  PRIMITIVE  ILIAC
Arteries.
   From the AORTA in this course are sent off the ar-
teries which are distributed to all the parts  of the  body
for their nourishment and animation.
   From the curve proceed t'he great branches which sup-
 ply the heart, the head, the upper extremities, and part
 of the thorax. Between the curve and the great primitive
 iliac arteries, the AORTA sends off those branches which
 supply the viscera contained in the cavities of the thorax
 and abdomen,* and part of the trunk of the body. The
 great ILIAC branches  of the AORTA are divided  into

   * It ought to be observed here, that the viscera in the lower part
 of the pelvis receive some branches from the internal iliac arteries. 
    Origin of the Subclavian and Carotid Arteries.  229

smaller  arteries, which supply  the whole  of the lower
extremities and some of the viscera of the  pelvis.
                    SECTION II.

   Of the Branches which go off from the arch of the

                     AORTA.
  THE proper arteries of the heart, denominated coro-
nary arteries, proceed from the AORTA so near to
the heart that their orifices are covered by the semilunar
valves, when those valves are pressed against the sides of
the artery. These  arteries have been described in the
account of the heart.—See p. 57.
   The arteries of the head and  of the upper extremities
proceed from the upper part of the curve in the following
manner.
   A large trunk, called  ARTERIA INNOMINATA,
goes off  first. This is more than sixteen lines in length,
when it divides into two branches: one of which supplies
the right side of the head, and is denominated the RIGHT
CAROTID: the other proceeds to the right arm, and from
its course under the clavicle, is called, at first, the RIGHT
SUBCLAVIAN.  Almost in contact widi the first trunk,
another artery goes off, which proceeds to the left side of
the head, and is called the LEFT  CAROTID.  Very-
near  to  this, arises the third artery, which proceeds  to
the left arm, and is denominated the LEFT  SUBCLA-
VIAN.  From these great branches originate the  blood-
vessels,  which are spent upon the  head  and neck and
the upper extremities.
   As these arteries arise from the curve of the AORTA,
they  are situated  obliquely with respect to  each other. 
 230    Situation of the Common Carotid Arteries.

 The ARTERIA INNOMINATA is not  only  to  the
 right, but it is also anterior to the  two others: and  the
 LEFT SUBCLAVIAN is posterior,  as well as to  the
 left of the  LEFT CAROTID and the ARTERIA IN-
 NOMINATA.


           THE CAROTID ARTERIES.
   The  two carotid arteries above mentioned have been
 denominated COMMON CAROTIDS, to distinguish
 them from their first ramifications,  which are called IN-
 TERNAL and EXTERNAL CAROTIDS.


           THE COMMON CAROTIDS
 Proceed towards the head on each side of the trachea: at
 first they diverge, but they soon become nearly parallel
 to each other, and continue so until they have ascended
 as high as the upper edge of the thyroid cartilage, when
 they divide into the INTERNAL and EXTERNAL
 CAROTIDS.
   These arteries are at first  very near each other, and
 rather in front of the trachea; they gradually diverge aad
 pass backwards and outwards  on the  sides of it, and of
 the oesophagus,  until they have arrived at the larynx.  In
 the lower part of the neck they are covered by the sterno
 mastoidei,  the sterno hyoidei,  and thyroidei, as well  as
 by the platysma myoidei muscles. Above, their situation
 is more superficial;  and  they are immediately under the
 platysma myoides.
  On the inside, they are very near the trachea and la-
 rynx,  and the oesophagus; on the outside, and rather ante-
 rior to them, are the internal jugular  veins; and  behind,
 on each side, are two important nerves  called the inter-
 costal and the par vagum. These bloodvessels and nerves
are surrounded  by absorbent vessels. 
External Carotid Artery.
231
  The COMMON CAROTID ARTERIES send off
no branches from their origin to their bifurcation; and
they appear to  preserve the same  diameter  throughout
their whole extent. In some few instances the right caro-
tid has been found larger than the left. The external and
internal branches into which they divide, are nearly equal
in the adult; but it is supposed that the internal is the largest
during infancy. The relative position of these branches
is also different at the commencement from  what it is
afterwards. The INTERNAL CAROTID forms a curve
which projects outwardly,  so  as to be exterior  to  the
EXTERNAL CAROTID, while this  last proceeds up-
wards, and rather backwards.


     THE EXTERNAL  CAROTID ARTERY
May  be considered as extending  from its commence-
ment, which is on a line with the superior  margin of the
thyroid cartilage, to the neck of the condyle of the lower
jaw, or near it.
  At first it is  superficial;  but  as it proceeds  upwards it
becomes deep-seated; and passing under the digastric and
stylo hyoidei muscles, and the ninth pair of nerves, is co-
vered by the Parotid Gland. After this, it again becomes
superficial; for the temporal artery, which may be regard-
ed as the  continuation  of  the  external carotid, passes
over the zygomatic process of the temporal bone.
  As the external carotid supplies  with blood the upper
part of the  neck and throat, the exterior of the head and
face, and the inside of the  mouth and nose; its branches
must necessarily be numerous,  and must pass in very va-
rious directions.
  Thus, soon after its commencement, it sends off, in an
anterior direction, three large branches; viz. to the upper
part of the  neck, to the parts within the  lower jaw, and to
the  cheeks and lips. These are denominated,  the supe- 
232    External Carotid and its Branches.

rior thyroid, the sublincual, and the facial. It
then sends off to the back of the head one which is called
the occipital; and, as it proceeds upwards near the con-
dyle of the lower jaw, another which passes internally, be-
hind the jaw, to the deep-seated  parts in  that direction.
After this, it forms the temporal artery, which supplies
the forehead and central parts of the cranium. Besides
these larger  branches, the external carotid sends off two
which are smaller; one from near the origin of the sublin-
gual artery,  which is spent principally upon the pharynx
and fauces,  and is called  the inferior pharyngeal:
and another, while it is involved with the  parotid gland,
which goes to the ear; and is therefore called posterior
auris.
  These arteries are distributed in the following manner.


        1. The Superior thyroid branch
Comes off very near the root of the external carotid, and
sometimes from the common trunk; it runs obliquely
downwards and forwards,  in a  meandering course, to the
thyroid gland, where it is spent.  During  this course it
sends off  one branch to the parts contiguous to the os
hyoides; another to the neighbourhood of the larynx: and
a third branch, which may be termed Laryngeal,  that
passes with  a small nerve  derived from the laryngeal
branch of the par vagum, either between the  os hyoides
and thyroid  cartilage, or the  thyroid and cricoid carti-
lages, to the interior muscles of the larynx;  and finally
returns again to terminate externally.
  While in  the thyroid  gland  this artery anastomoses
with the inferior thyroid,  and  also with its fellow on the
opposite side. 
Branches of the External Carotid.       233
      2. The lingual, or sublingual branch,
 Goes off above the last mentioned artery, and very near
 it;  but in a very different direction, for it runs  upwards
 and forwards, to the tongue. In this  course it crosses
 obliquely the os hyoides, and is commonly  within the
 hyoglossus muscle. It gives  off  branches to the middle
 constrictors of the pharynx, and to the muscles contigu-
 ous to the tongue.  It also sends off a branch which  pene-
 trates to the back of the tongue,  which is called, from its
 situation, Dorsalis Lingua. At the anterior margin  of the
 hyoglossus  muscle it divides into two branches,  one of
 which passes to the  sublingual  gland and the adjacent
 parts, and  is thence called  Sublingual; while the  other
 branch, the Ranina, passes by the side of the genio glos-
 sus muscle to the apex of the tongue.


      3. The facial or  external maxillary,
 Runs obliquely upwards and forwards under the  ninth
 pair of nerves, the  stylo hyoideus muscle and the tendon
 of the digastric, across the lower jaw and  cheek, towards
 the inner corner of the eye,  in a serpentine course. Be-
 fore it crosses the jaw it sends off several branches, viz:
 to the pharynx, the tonsils, the  inferior maxillary gland
 and the  parts contiguous to it.  It also sends a branch
 towards the chin, which  passes between  the mylo-hyoi-
 deus, the anterior belly of the digastric, and the margin
 of the lower jaw: and some of its branches  continue to
 the muscles of the under lip. This branch is called the
 Submental.
  This  artery then passes round the basis or inferior
edge of the lower jaw, very near the anterior margin of
the masseter muscle, and is so superficial that its pulsa-
tions can be readily perceived. After this turn, its course
  Vol. II.              2 G 
334-       Branches of the External Carotid.
is  obliquely upwards, and forwards.  Near the basis of
the jaw it sends off a  branch to the masseter, which
anastomoses with small  branches from the temporal;  and
another which passes superficially to  the under lip  and
contiguous parts of the cheeks. This last is called the
Inferior Labial.
   After the artery has passed  as high as  the teeth in the
lower jaw, it divides into two branches; which go,  one
to the under, and the other to  the upper lip: that to the
upper lip is largest. These branches are called Coronary.
   The Coronary Artery of the lower lip passes under the
muscles called Depressor Anguli  Oris, and  Orbicularis
Oris, into the substance of the lip, and anastomoses with
its fellow of the  opposite side.
   The  Coronary Artery of the upper lip  passes under
the zygomaticus major  and the orbicularis, and very near
the  margin of the  upper lip  internally.  It also anasto-
moses freely with its fellow on the  opposite side. These
anastomoses  are frequently so  considerable that  the ar-
teries on one side can be well filled by injecting those of
the  other. The  coronary branches, as well as  the  main
trunk  of the facial artery, observe a serpentine  or tor-
tuous course; in consequence  of which they admit of the
motions of the cheeks and  lips, which they  would greatly
impede if they were straight.
   From the upper coronary artery a branch continues in
the  direction  of the main  trunk  of the facial artery, by
the  side of the nose, which extends upwards, sending off
small branches in its course, and finally terminates about
the  internal angle of the eye and the forehead.


           4. The inferior  pharyngeal
 Is a very small  artery;  it arises posteriorly from the ex-
 ternal carotid,  opposite to the origin  of the sublingual,
 and passes upwards to  the basis  of the  cranium. In this 
Branches of the External Carotid.        235
course it sends several branches to the pharynx,  and to
the deep seated parts immediately contiguous.
   It also sends branches to the first ganglion of the inter-
costal  nerve, to the par vagum, and  to the lymphatic
glands of the neck; and finally it enters the  cavity of the
cranium by the posterior foramen lacerum.
   In some cases it also sends a smail branch through
the anterior foramen lacerum.


             5. The occipital artery
Arises from the posterior side of the external carotid,
nearly  opposite to  the facial, but sometimes higher up;
it  ascends obliquely, and passes to the back part  of the
cranium, between the transverse process of the atlas and
the mastoid process of the temporal bone.
   In this course it passes  over the internal jugular vein
and the eighth pair of nerves, and under  the posterior
part of the digastric muscle; it lies very near to the  base
of the  mastoid process,  and under the muscles which are
inserted into it. After emerging from  these muscles, it
runs superficially upon the occiput, dividing  into branches
which  extend to those of the temporal  artery.
   The occipital artery sends off branches  to the
muscles which are contiguous  to it, and to  the glands of
the neck.
   It also gives off the  following branches: One called
the Meningeal, which  passes through the posterior fora-
men lacerum  to the under and back  part   of the dura
mater:  one to the exterior parts of the ear: another which
passes  downwards, and is spent upon the complexus,
trachelo mastoideus, and other muscles of the neck: and
several smaller arteries.
   The artery next  to be described, is sometimes sent off
by the  occipital artery. 
236      Branches of the External Carotid.


 6. The posterior  auricular, or stylo mastoid
                      artery,
When it arises from the external carotid, comes off pos-
teriorly from the artery,  where it is involved with  the
parotid gland, and passes backwards between the meatus
auditorius externus and the mastoid process. It then as-
cends, in a  curved direction, and terminates behind the
ear.
   In this course it sends off  small branches to  the paro-
tid gland, and to the digastric  and sterno mastoid muscles.
Sometimes a distinct branch, which is particularly visi-
ble in children, passes through an aperture  in the meatus
auditorius externus, and is spent on its internal surface.
   It also sends off a branch which enters into  the Stylo
Mastoid Foramen, and supplies small vessels to  the mem-
brana tympani and the lining  membrane  of the cavity of
the tympanum; to the mastoid cells; to the  muscle of the
Stapes, and  to  the  external semicircular canal.  One of
these vessels anastomoses, in  the upper and posterior part
of the cavity of the tympanum, with a small twig derived
from  the artery of  the dura  mater. When it has arrived
behind  the  ear,  the  Posterior  Auricular Artery  termi-
nates upon the external ear and the parts contiguous to it.


      7. The internal maxillary artery*
Arises from the external carotid under the parotid gland,
at a little distance below the  neck of the condyloid pro-

  * The general situation of this artery, and the distribution of se-
veral of its most important branches, cannot be understood without
a knowledge of the bones through which they pass. The student of
surgery will therefore derive benefit from a re-exan.ination of these
bones, and of the zygomatic fossa, &c. when he studies this artery.
(See Vol. I. page 61.)—He ought to be well acquainted with this 
            The Internal Maxillary Artery.        237

cess of the lower jaw, and extends to the bottom of the
zygomatic fossa; varying its direction in  its course. It
is rather larger than the temporal.
  a. It first sends off one or two small branches to the
ear, and a twig which penetrates into  the  cavity of the
tympanum by the glenoid fissure.
   b. It  also sends off a small  artery called the  Lesser
Meningeal, which passes  upwards,  and  after  giving
branches to the external pterygoid and the  muscles of
the  palate,  passes through the  foramen  ovale,  and is
spent upon the dura mater about the sella turcica.
   c. It  then  sends off one of its largest  branches, the
Great or Middle Artery of the Dura Mater, which passes
in a straight direction to the foramen spinale, by which
it enters into the cavity of the cranium.
   This  artery ramifies  largely on  the  dura mater, and
makes those arborescent impressions which  are so visible
 in  the parietal bone. It generally divides into two  great
 branches: the anterior, which is the largest, passes  over
 the anterior and inferior angle  of the parietal bone: the
 posterior branch  soon divides  into many  ramifications,
 which are extended laterally and posteriorly.
   It furnishes the twig which  passes  to the ear by the
 hiatus  of Fallopius,  and  anastomoses with the  small
 branches of the stylo mastoid artery.
   It also supplies some other small vessels which pass to
 the cavity of the tympanum by small foramina  near the
 junction of the  squamous and petrous portions of the
 temporal bone.
    d. The next branch sent off  by the internal maxillary
 leaves it about an inch from its origin, and is called the
 Inferior Maxillary.  It passes between the  internal ptery-

 subject, if he should undertake the management  of necrosis of the
 jaw bones; or of those fungous tumours, which sometimes originate
 in the antrum maxillare; as well as of several other complaints. 
238        The Internal Maxillary Artery.
goid muscle and the bone, and after giving small branches
to the contiguous muscles, enters the canal in the lower
jaw, in company with the nerve.  This canal has a very
free  communication with the cellular structure  of  the
jaw, and the artery in its progress along it sends branches
to the  respective teeth and the  bone. At the anterior
maxillary foramen, this artery sends off a considerable
branch, which passes  out and anastomoses  with the ves-
sels  on the chin, while another branch passes forward
and  supplies the  canine and incisor teeth and the bone
contiguous to them.
   Sometimes the inferior maxillary artery divides into
two  branches before  it has  arrived at this foramen.  In
this case, one of  the arteries passes out of the foramen,
while the other continues to the symphysis.
   e.  Two branches  pass  off to  the temporal muscle,
which originate at a small distance from each other: one
of them passes upwards on the tendon of the temporal
muscle; the other arises near the tuberosity of the upper
maxillary bone: they are  called the exterior  deep, and
the interior deep  temporal artery. They are both spent
upon the temporal muscle; but the interior branch sends
a small twig into  the orbit of the eye.
   i. There are some  small  branches which pass to  the
Pterygoid  Muscles  and to  the Masseter, which arise
either from the internal maxillary artery, or from the an-
terior deep temporal. They are generally small, and often
irregular.
   g. An artery, particularly appropriated  to the  cheek,
perforates the buccinator muscle from within outwards,
and generally terminates on the buccinator, the zygoma-
ticus major and the muscles of the lips. This Artery oj
the Cheek is very irregular in its origin, sometimes aris-
ing from the internal maxillary,  sometimes  from  the
deep  temporal, and sometimes from the suborbitary,  or
from the alveolar  artery, to  be immediately described. 
           The Internal Maxillary Artery.        239

  h. The Alveolar Artery, or the  Artery of the Upper
Jaw,  arises generally from  the  internal  maxillary,  but
sometimes from one of  its branches. It winds round the
tuberosity of the upper  jaw,  and sends branches to the
buccinator muscle, to the bone and the gums, to the an-
trum  highmorianum,  and some of the molar teeth:  and
also to the teeth generally, by means of a canal which is
analogous to that of the  Lower jaw.
   i. The Infra-orbitar  Artery arises from  the internal
maxillary in the  zygomatic  fossa, and soon enters the
infra  orbitary canal, through which it passes to the face,
and emerges below the orbit of the eye,  supplying the
muscles in the vicinity,  and anastomosing with the small
ramifications ef the two last described arteries, and also
of the facial artery and the ophthalmic.
   This artery in its  course sends  off small twigs to the
periosteum,  the adipose  membrane, and  the muscles
in  the inferior-part  of  the orbit, and also to the  great
maxillary sinus or antrum highmorianum, and to the ca-
nine and incisor teeth.
   j. The Palato Maxillary, or Superior Palatine Artery,
arises also in the zygomatic fossa,  and,  descending  be-
hind  the upper maxillary bone, enters the posterior pala-
tine canal. It generally forms two branches, the largest
of which advances  forward, supplying the palate and
gums, and finally sends a twig through the foramen in-
 cisivum to the nose, while  the  posterior branch, which
 is much smaller, supplies the velum pendulum palati.
    K. The Pterygo Palatine, or Superior Pharyngeal, is
 a small  vessel, which  sometimes arises  from the artery
 next to be mentioned.  It is spent upon the upper part of
 the pharynx, and a branch passes through the pterygo
 palatine foramen, which is  spent upon  the arch of the
 palate and the  contiguous parts.
    l. The internal  maxillary at length terminates
 in the  Spheno-Palatine, or  Large Nasal Artery,  which 
 240               Temporal Artery.

 passes through the spheno-palatine foramen to the back
 part of the nose. This artery sometimes separates into
 two branches before it enters the foramen; sometimes it
 enters singly, and divides into two branches soon after;
 one of them is spread upon the  septum, and the other
 upon the external side of the nose; each of these branches
 ramifies very minutely upon the Schneiderian membrane
 and its process in the different sinuses, and also in the
 ethmoidal cejls.


             8. The temporal  artery
 Is considered as the  continuation  of the  external carotid,
 because it preserves the direction  of  the main trunk, al-
 though the internal maxillary is larger.
   After parting with the internal maxillary it projects out-
 wards; and parsing between the Meatus Auditorius Ex-
 ternus  and  the condyle of the lower jaw, continues up-
 wards, behind the root of the zygomatic process of the
temporal bone, to the aponeurosis of the temporal muscle:
 on  the outside of which, immediately under the integu-
 ments, it divides  into two  large  branches denominated
anterior and posterior.
  Before this division the temporal artery sends off seve-
 ral branches of very different sizes.
  One, which  is considerable  in size,  and called  the
 Transverse Facial Branch, advances forwards across the
neck of the condyle of the  lower  jaw, and giving small
branches to the masseter, runs parallel to the parotid duct,
and below it. This branch is spent upon  the muscles  of
the face, and  anastomoses with the other vessels of that
part.
  The temporal gives off small branches to the parotid
gland and to  the articulation of the jaw. From the last
mentioned  branch  small  twigs pass to  the ear,  one  of 
          Temporal Artery. Internal Carotid.      211

which enters the cavity of the tympanum by the glenoid
fissure.
   While  this artery is on a  line with  the  zygoma, it
sends off a branch called the middle temporal artery, which
penetrates the aponeurosis of the temporal  muscle, and
ramifies under it upon the muscle in an anterior direc-
tion.
   The two great branches of the temporal artery are dis-
tributed in the following manner. The Anterior passes up
in a serpentine direction on the anterior part of the tem-
ple, and supplies the front side of the head, and the upper
part of the forehead.
   The Posterior extends upwards and  backwards, and
supplies the scalp on  the  lateral and  middle part of the
cranium,  and also the bone.
   Ramifications from each of these branches anastomose
on the upper part of the cranium  with those of its fellow
of the opposite side. The  anterior branch also anastomo-
ses on the forehead with the facial and ophthalmic artery;
and the posterior branch with the occipital artery on the
back part of the head.


     THE INTERNAL CAROTID  ARTERY
   Is sometimes called the Artery of the Brain, as it is
almost entirely appropriated to that viscus.
   From its origin to the commencement of its ramifica-
tions the course of this bloodvessel is peculiarly tortuous.
In consequence of which, the  force of the blood in it is
greatly diminished before  it arrives at the brain.
  An  instance of  this curvature  occurs immediately
after its separation from the external carotid, when it pro-
trudes outwards so much as to be exterior to that vessel;
after this,  it ascends to the carotid canal, and in its course
is in contact, or very  near the par vagum and intercos-
tal nerves.
  Vol. II.              2 H 
242       Curvatures of the Internal Carotid,

  The carotid canal in the os petrosum is  by no means
straight; it forms a semicircular curve, forwards and in-
wards; and its upper portion, which is nearly horizontal,
opens obliquely against the body of the sphenoidal bone
at a small distance from it.  Therefore,  after the artery
has passed  through the canal, it must turn upwards  to
get fairly into the cavity of the cranium; and of course,
its direction while in the canal, forms almost a right angle
with its direction  before it enters, and  after it emerges
from it.
  In  consequence of this curvature,  much of the mo-
mentum of  the blood must be impressed upon the cra-
nium.
  After the artery has arrived at the  end of the carotid
canal, and has turned upwards to get within the cavity of
the cranium, it bends forwards, and  passes nearly in a
horizontal direction, through the cavernous sinus on the
side of the sella turcica, to the anterior clinoid process;
here it again forms a considerable curve, which is directly
upwards, and then it perforates the dura mater.
  These curvatures must also deprive the blood of the
carotid of a portion of the momentum which it has re-
tained after  leaving the bone.
  The object of these various flexures of the internal ca-
rotid appears to be analogous  to that of the Rete Mir a-
bile in certain quadrupeds, which is formed by the divi-
sion  of this artery into many small branches, that reunite
again, without producing any other effect than the dimi-
nution of the momentum of the blood.
  During its course from the place of bifurcation to its
entrance into the carotid canal, the internal carotid arte-
ry very rarely sends off any  branches. In  the  canal  it
gives off a small twig which enters the cavity of the tym-
panum; and sometimes  a second which unites with the
Pterygoid branch of the internal maxillary.
  As it goes by the sella turcica, it passes through the 
Ophthalmic Artery.              243 "
cavernous sinuses, and gives off two branches which are
called the Posterior and Anterior arteries of the Caver-
nous Sinus or Receptacle.
  The posterior branch goes to that part of the dura ma-
ter which is connected with the posterior clinoid process,
and the cuneiform process of the occipital bone.  It like-
wise gives branches  to several of the nerves which  are
contiguous, and to the pituitary gland.
  The anterior artery also gives branches  to  the  conti-
guous nerves, to the dura mater, and the pituitary gland.
  When the internal carotid turns upwards at the  anterior
clinoid process,  it sends off the


               ophthalmic artery,
Which passes under the optic nerve through the foramen
opticum into the orbit of the eye, and is about two lines
in diameter.
  Although this artery enters the orbit under the optic
nerve, it soon takes a position on  the outside of it;  but
afterwards gradually  proceeds to  the inner side of  the
orbit, crossing over this nerve in an oblique direction,  and
finally passes out of the orbit near the internal angle. In
this spiral course it sends off numerous branches, viz.
  a.  To those parts which are auxiliary to the eye.
  b.  To the ball of the eye.
  c.  To the cavity of the nose, through small foramina
in the ethmoid bone, and
  d.  To the forehead and external side of the nose.
  These branches generally  go off in the following  order-
  The Lachrymal artery arises  soon after the ophthal-
mic arrives within the orbit, and passes above the abduc-
tor muscle to the lachrymal  gland,  where it terminates,
sending off many small branches in  its course.
  The Central artery  of the retina also leaves the ophthal-
mic soon after its arrival in the orbit: it is a small  vessel 
244      Branches of the Ophthalmic Artery.

which penetrates into the center of the optic nerve, and
passing with it into the eye  is spread upon the internal
surface of the retina. Here it appears to terminate in the
adult; but in the foetus it is continued through the vitreous
humour to the capsule of the crystalline lens.
   While  the ophthalmic is passing over the optic nerve
the branches  which enter the  ball of the eye leave it.
Their number varies,  but they form three classes, viz.
The Long  Ciliary, the Short Ciliary,  and the Anterior
Ciliary arteries. (See description of the eye, vol. i. p. 341.)
The supra  orbitary and muscular branches leave it also
near the same  places.
   The  Supra Orbitary Branch often gives off several
muscular twigs: but it passes out of the orbit through the
supra  orbitar  foramen, and  generally divides into two
branches,  one of which is spent upon the periosteum, and
the other  upon the skin and muscles of the forehead.
   There are sometimes two muscular branches, a Superior
and an Inferior. The superior branch is often deficient:
when  it exists it supplies the levator palpebras, the levator
oculi, obliquus superior,  &c;  but these parts are often
supplied by the  branches above  mentioned. The supra
orbitar ^o  frequently gives off branches to the muscles that
it  has been called the Superior Muscular Branch.  The
inferior muscular branch is more constant.  It commonly
supplies the rectus inferior, the adductor, and the inferior
oblique muscles, and also the lachrymal sac, and the low-
er eyelid,  &c.
   When the artery is on the  inside of the nerve  it sends
off the two branches to the cavity  of the nose, viz. The
Ethmoidal Arteries; and also, branches to the eyelids.
   The Posterior Ethmoidal branch is first. It passes be-
tween the levator and  adductor muscles, and above the
obliquus superior; and penetrates the cavity of the crani-
um by the posterior orbitary  foramen:  after giving some
twigs to the dura mater, it passes to the posterior cells 
          Branches of the Ophthalmic Artery.     245

of the ethmoid  by the foramina of the cribriform  plate
of that bone, and sends a small branch to the Schneide-
rian membrane on the back part of the septum of the nose.
  The Anterior Ethmoidal artery arises from the ophthal-
mic  nearly opposite  to  the  anterior  orbitary foramen,
through which  it passes:  and after entering the cranium
is distributed like the other through some of the foramina
of the cribriform plate to the anterior cells of the ethmoid
bone, and to the anterior part of the Schneiderian mem-
brane on the septum of the nose, to  which  it sends a
considerable branch.
   In its course it sends twigs to the frontal sinuses, and
to the dura mater and its falciform process.
   The arteries of the Palpebra are called Superior and
Inferior; they leave the ophthalmic near the loop or  pully
of the superior oblique  muscle. The  inferior comes off
first; it sends branches to the ligaments of the tarsus, the
caruncula lachrymalis, and the parts connected with  the
cartilage of the under eyelid, and  unites with the lachry-
mal artery near the  external canthus, forming an arch
called the Inferior Tarsal Arch.
   The Superior Artery  supplies the superior part of the
orbicularis muscle, the ligament and caruncula also: and
it likewise unites with a  twig of the lachrymal, and forms
the superior tarsal arch.
   Soon  after sending off the palpebral branches,  the
Ophthalmic Artery arrives at  the internal canthus, and
then finally divides into  two  branches, the nasal and the
frontal.
   The Nasal Branch passes above the superior part of
the lachrymal  sac and the ligament of the eyelid to the
nose; after sending a twig to the frontal muscle and the
lachrymal sac,  it  passes down the side  of the nose and
anastomoses with the facial artery.
   The Frontal Artery is not so large as the nasal; it gene-
rally divides into three parts. A superciliary branch which 
 246 Internal Carotid. Middle Artery of the Brain.

 is principally  spent  upon  the eyebrows;  a superficial
 branch which is spent upon the forehead; and a branch
 which is distributed to the pericranium.
   The INTERNAL CAROTID, soon after parting with
 the ophthalmic, sends off, in a posterior direction, a branch
 to join one from the vertebral artery. From its destination
 this vessel is called the arteria  communicans.
   After this it sends off another branch, which is so large
 that it may be considered as a continuation of the main
 trunk: this is called the middle artery of the brain,
 or the arteria sylviana.  It runs outwards nearly in
 the direction of the fossa Sylvii, which separates the an-
terior from the middle lobes of the cerebrum. In its course
 it divides  and subdivides into  numerous branches which
are spread upon  the Pia Mater,  and finally enter  the
surface of the brain in a very  minute state.
   The internal carotid then terminates in a branch which
is smaller  than the last mentioned, and from its situation
is called the anterior artery of the brain, or ar-
 teria callosa.  This vessel first inclines towards its
fellow on the opposite side, and after approaching within
half an inch of it,  forms another curve, and runs forward
to the anterior part of the brain, dividing itself gradually
into branches which pass in several directions.
   When these anterior arteries are nearest to each  other,
a small Transverse branch, which passes at right angles,
connects them together. This branch completes the ante-
rior part of the Circle of Willis. It crosses  immediately
before the sella turcica and pituitary gland, and sends off
branches which pass  to the  third ventricle, to the fornix
and septum lucidum, and also  to the pia mater.
   The anterior arteries of the brain also send off
branches to the optic and olfactory nerves;  to the opposite
surfaces of the two hemispheres on each side of the falx;
to their inferior surfaces, and to the  corpus callosum.
   They have likewise some branches which anastomose 
         Right and Left Subclavian Arteries.       247

with those of the middle artery of the brain, and of the
vertebral artery.


            The SUBCLAVIAN Arteries.
   The RIGHT SUBCLAVIAN may be considered as
the  continuation  of  the  arteria  innominata.  This  last
mentioned artery, after leaving the  aorta, forms a curve
or  arch, which extends obliquely  backwards  and out-
wards, over the first rib to the axilla, crossing the trachea
in its course. At the distance of an inch and a quarter, or
an inch and a half from its origin, it sends off the right
carotid, and then, assuming the name of Right Subclavian,
continues in the above stated direction.
   The cord of the curve of this artery, and the cord  of
the curve of the aorta, are not in the same direction, but
form an angle with each other.
   The position of the LEFT SUBCLAVIAN is some-
what different from that of the right. Its origin is poste-
rior, and, therefore, the direction of the cord of its curve is
more immediately lateral. The curve or arch is also smal-
ler. The situation of the two subclavians as  relative to
 the* contiguous parts, is, therefore, somewhat different;
 but each of them proceeds between the anterior and  the
 middle scaleni muscles,  and when they have  arrived at
 these muscles, their  respective positions are very similar.
    The anterior and middle scaleni muscles arise from the
 transverse processes  of several  of the cervical vertebrae,
 and are inserted into the first rib, one before the other, so
 as to leave a considerable space between them. The sub-
 clavian arteries pass  through this space, and before they
 arrive at it, but when they are very near the above men-
 tioned muscles,  they  send off several  very  important
 branches in various directions,  viz.  to the cavity of the
 cranium, to the  parietes of the thorax, to  the thyroid
 gland, and  to the lower part of the neck. 
248      Course and Distribution of the Inferior
  They proceed near to the scaleni muscles before they
send off any branches; and it is to be observed,  that the
subclavian veins which  correspond  with  these  arteries,
are  anterior to them,  for they pass before  the scaleni
muscles, and not between them.


         The  internal mammary  Artery
Goes downwards, from the lower and anterior part of the
subclavian, along the inner side of the  anterior  scalenus
muscle. It proceeds, exterior to the pleura, across the car-
tilages of the true ribs, and near their middle; and, con-
tinuing between the cartilages and the diaphragm, exterior
to the  peritoneum, terminates on the rectus abdominis
muscle, in  branches which anastomose with those of the
epigastric artery.  In this course it gives branches to al-
most all the parts to which it is contiguous, viz. to the
muscles and glands at the lower part of the neck; to the
thymus gland; to the parts in the intercostal spaces; to the
sternum; to the mediastinum  and  pericardium; to the
diaphragm  and to the muscles of the abdomen.
  From some  of its ramifications upon the parts between
the ribs, small branches go off to the mamma,  and thereby
give a name to the  artery. There is also a small vessel
which is sent off by the mammary arterv, or by one of its
upper branches, which accompanies the phrenic nerve to
the diaphragm.


           The inferior thyroid Artery
Arises from the upper  side of the subclavian nearly op-
posite to the origin of  the internal mammary. It passes
upwards and inwards, between the carotid artery and  the
spine, to the thyroid gland: then it anastomoses with the 
          Thyroid and the Vertebral Arteries.       249

branches of the superior  thyroid on the same side, and
With those of its fellow on the opposite side.
  This vessel sometimes sends off  large branches to the
muscles at the lower part  of the neck.


               The vertebral Artery
Arises from the upper and  posterior part of the subclavian.
It goes upwards and backwards between the muscles which
lie on  the front of the spine, and passing under the trans-
verse process of  the sixth or seventh  cervical  vertebra,
enters into the canal formed  in the  transverse processes
of the vertebrae.  In this course, as it proceeds from the
third to the second cervical vertebra, it inclines outwards
laterally, and, in its passage from the transverse process
of the second to that of the first vertebra, it forms a con-
siderable curve, the convexity of which has a lateral and
external aspect. After passing  the  transverse  process of
the Atlas, it is turned suddenly backwards, in a groove,
and finally passes through the great  occipital foramen into
the cavity of the  cranium.  It then proceeds upon the cu-
neiform process of the occipital bone, under the Medulla
 Oblongata, and joins its fellow so as  to form an acute angle
with it near the union  of  the medulla oblongata with the
pons Varolii. From each  of the vertebral' arteries, before
their union, there generally goes off a small branch called
the Posterior Meningeal, which is spent upon the posterior
part of the dura mater.
   The trunk formed by the union of the vertebral arteries
is called


                The BASILAR Artery.
It extends forward near to the anterior  part of the pons
Varolii, where it bifurcates; but previously sends off se-
veral  branches  on each side. The  first pair go  off in a
   Vol. 11.              2  I 
250                Basilar Artery.

lateral direction, soon after its commencement,  near the
back part of the pons Varolii, and are spent upon the me-
dulla oblongata, the pons Varolii, and the other contigu-
ous parts, and also upon the fourth ventricle and the Plex-
us Choroides of that cavity. They are called the Posterior
or Inferior Arteries of the Cerebellum.
   Two other lateral branches, which are called the Su-
perior Arteries of the Cerebellum, go off from the basilar
artery, near its anterior extremity.  These are principally
spent upon  the crura of the cerebellum  and  cerebrum;
upon the cerebellum itself, and the contiguous parts.
   Soon after sending off the  last mentioned arteries, the
basilar artery divides  into  two  branches,  which also
take a lateral direction, and are of considerable size. In
their course outward, these  branches  are curved  with
their convexity forward.  About ten or twelve  lines from
its commencement, each of them sends off a branch called
the arteria communicans, which passes directly for-
ward, and communicates with the internal carotid, thus
forming the  arrangement, which is  called  the Circle of
fVillis.* After  sending off these arteries, they continue
their lateral direction, and  are distributed principally to
the posterior parts of the cerebrum. These terminating
branches of The  basilar artery are called the Poste-
rior Arteries of the Cerebrum.

  * The arteria communicans is also considered a's a branch of the
Internal Carotid. The arrangement here alluded  to is very remark-
able. As the branches which pass off laterally from the single trunk
of the Basilar Artery unite to the Internal Carotids* and  the Internal
Carotids are united to each other, there is an uninterrupted,  conti-
nuation of artery, which incloses a portion of space of a determined
form; but this form resembles an oblong square more than a circle.
By this connexion blood will pass from any one of the four arteries
•f the brain to all the others. 
Arteries of the loiver part of the Neck.      251
         The superior  intercostal Artery
Arises from the upper part of the Subclavian, after the
Vertebral and Thyroid arteries, and very near them. It de-
scends by the side of the spine across the first and second
ribs, near their heads, and exterior to the great intercostal
nerve. It generally  forms two branches,  which are ap-
propriated to the muscles, &c, in the first and second
intercostal spaces, and sometimes a small branch is con-
tinued to the  third intercostal space. From each of these
branches a small vessel proceeds backwards, and is spent
upon the contiguous muscles,  &c, on the back  of the
thorax. The intercostal artery also sends a branch
upwards to the deep seated parts of the neck.
  In addition to the arteries above mentioned, there are
several others of considerable size, which originate either
directly or  indirectly from the SUBCLAVIAN, and are
spent upon the lower portion of the neck, and the conti-
guous parts.  These arteries are very different in different
subjects, especially as to their origin. Two of them, which
have been called the anterior and posterior cervi-
CALs.are generally distributed to the muscles and other
parts which lie on the lower portion of the neck anteriorly
and posteriorly.
  A third, which passes  transversely on the lower part of
the neck, is called the superior scapular.
  In some cases the two cervical ARTERiEsarisefrom
the subclavian, after the  mammary and the thyroid, in a
common trunk, which   soon  divides. Very  frequently
they go off from the Inferior Thyroid. Sometimes one of
them goes  off from the Inferior Thyroid, and  the other
from one of the branches  of the Subclavian.*

  * Haller paid great attention to the arterial  system, and made
many dissections, with a view to engravings of it, which he publish-,
ed with descriptions, in folio fasciculi.
                                                The» 
252       Branches that go off in the Axilla.

  The Superior  Scapular most  commonly  arises with
some other  arterv,  and  very often from the  Inferior
Thyroid. It runs transversely outwards, within and above
the clavicle, and  passing through the notch in the upper
costa ofthe scapula, divides into  branches which are dis-
tributed to the parts on the dorsum  of that bone.
 < The SUBCLAVIAN ARTERY, in its progress from
the aorta to the axilla, forms an arch or curve,  over the
first  rib, as has  been  already observed.  The anterior
scalenus muscle  is before it, and the great nerves of the
upper extremity are above it.  After passing  between the
scaleni it descends upon the first and second rib into the
axilla. The  nerves  which were  above,  descend with it:
at first they are necessarily exterior to it, but they  form a
plexus which the artery  enters  into, so as  to  be partly
surrounded  by them. This course  of  the artery is ob-
liquely under the clavicle, and  behind the pectoral muscle.
In the axilla, the vessel and nerves which surround  it are
placed  between  the tendons  of the pectoralis and the
latissimus dorsi muscles. Here the artery takes the name
of AXILLARY, and sends off several important branches.
   The principal branches that go off from the axillary
artery are distributed
   1st. Anteriorly, to the pectoral muscle, and the  parts
on the anterior surface of the  thorax.
   2d. Posteriorly, to the muscles which are on the sca-
pula and contiguous to it; and
   3d. To the parts which are  near the upper  extremity of
the os humeri.

  These fasciculi have been collected,  and, with some other engrav-
ings, form a  large volume,  entitled  ICONES  ANATOMICAL,
which is truly valuable.
  There are some very interesting observations on this work of Hal-
ler's, and also on these arteries, in a DESCRIPTION OF THE
ARTERIES, by Dr. Barclay of Edinburgh, which I have read with
advantage, as well as a  work on the muscles by the same author. 
Branches that go off in the Axilla.
253
                 Anterior Branches.
  The arteries which go to the pectoral muscle, &c, are
very various in different subjects, both as to their number,
origin, and size.
  They  have also been  called  by  different names,  as
THORACICiE, MAMMARliE EXTERNA, &.C.
  There are almost always three of them, and very often
more; one of them, which is called by several authors the
Acromialis, proceeds towards the end of the clavicle, and
generally passes out at the interval between the deltoid
and the pectoral muscle, sending various branches to the
contiguous parts; the largest of its branches often passing
in the direction of the interstice between those muscles.
   Another  of these arteries, which is called  Superior
 Thoracic, is generally  very small: it often is  a branch
 of the above mentioned Acromialis.
   There is very often to be found here an artery called
 the Inferior Thoracic, or the External Mammary, which
 is  of considerable length,  although its diameter is  not
 very great.  This artery originates  near the two last  men-
 tioned, and sometimes from the Acromialis.  It often ex-
 tends downwards as low as the sixth rib, and send branch-
 es to the anterior part of the thorax, to the mamma,  and
 the other contiguous parts. Many of the small branches
 of this artery anastomose very freely with those of the in-
 ternal mammary.
    There are always small arterial branches in  the axilla,
 which ramify upon the glands and adipose matter always
 existing there.  They often arise by one common trunk,
 which is called the Axillary Thoracic.


                   Posterior Branch.
    One large artery is commonly sent to the muscles on
 the scapula, which is called the sc apul ar, the common 
254      Branches that gd off in the Axilla.

scapular, or the internal scapular. It commonly
passes off from the axillary  after the  thoracic arteries,
and supplies the muscles on both surfaces of the scapula.
This large  vessel passes downwards a short distance in
the direction of the inferior costa of the scapula, and soon
sends off a branch that winds  round to the dorsum of the
bone, to be distributed to the infra spinatus and the con-
tiguous  muscles, which is called the Dorsalis Scapula.
The main trunk then inclines to  the subscapularis mus-
cle, and generally  divides into two  branches, which are
distributed to the  subscapularis,  teres major, latissimus
dorsi, &c.
  Sometimes the  scapular  artery divides  into two
branches before it sends off  the dorsal. In this case  the
last mentioned artery goes off from one of those branches.


            Branches near the Os Humeri.
  The arteries which are near the body of the os humeri
at its  upper end, are generally two in number, and deno-
minated the Anterior and Posterior Circumfiexa. Some-
times they arise separately, and sometimes in a common
trunk from the AXILLARY artery. Frequently one of
them  arises from the scapular.
  The Anterior  Circumflex   passes between the  united
heads of the biceps and coraco  brachialis muscles and
the body of the os humeri, at a small distance below its
head. It sends branches to  the capsular ligament,  the pe-
riosteum of the os humeri, the membranes of the groove
for the long head of the biceps, the upper portions of the
biceps and coraco brachialis,  and some contiguous mus-
cles.
  The Posterior Circumflex  proceeds between the sub-
scapularis and teres major muscles, and continues  be-
tween the os humeri and the head of the triceps and the 
           Situation of the Humeral Artery.        25S

 deltoides. It is distributed to the musdes and parts about
 the joint, especially the deltoides.
   These arteries surround the os humeri, and the  small
 branches anastomose with each other. The Posterior Cir-
 cumflex is much larger than the Anterior.
   The great artery of the arm proceeds from the  axilla
 to the elbow; and, during this course, is generally deno-
 minated


              The  HUMERAL Artery.*
 Its direction is influenced by the position  of  the os hu-
 meri.  When the arm hangs down, with the palm of the
 hand  presenting forward, this  direction is  somewhat
 spiral. The situation of the artery is on the inside of the
 biceps muscle,  and between that muscle and  the triceps
 extensor. It also continues very near and  on  the inside
 of the tendon of the biceps, and under the Aponeurosis
 which proceeds from that tendon. In consequence of the
 spiral  or oblique course of the artery, its direction would
 be from the inside of the tendon of the biceps to the ra-
 dial side of the fore arm,  but soon after it passes across
 the joint of the elbow, it divides into two branches: one
 which preserves, for some distance, the direction of the
 Mam  Trunk, is called the radial artery:  the other,
 which  inclines  obliquely  downwards and  towards the
 ulna, is the  common  trunk  of the  ulnar and in-
 terosseal arteries.
   During this course, the HUMERAL artery sends off
 several branches to  the muscles and other parts on the
 os humeri. The largest of them is denominated the  Pro-
funda Humeri, or  Spiralis. This artery very often arises
 as high as the insertion of the latissimus dorsi, and pass-
 ing  between the heads of the  triceps extensor muscle,
* It is also called Brachial Artery by several writers. 
 256        Branches of the Humeral Artery.
proceeds downwards  under that muscle,  in a spiral di-
rection, towards the external or radial  condyle. It sends
several branches to  the triceps and the contiguous mus-
cles, and  one considerable branch, which  is generally
called  the Profunda Minor, to  the  parts  contiguous to
the internal condyle. The ramifications of these branches
near the  condyle  frequently anastomose  with  small
branches of the radial  and ulnar arteries.*
  A small  branch frequently arises from the humeral
artery, at a short distance from the Profunda Humeri,
which  sends a ramification to the medullary foramen of
the os  humeri.  This vessel is, therefore, denominated
Arteria Nutritia.
  There aie very often several anastomoses between the
branches of the  HUMERAL artery, which originate
above the elbow, and certain branches of the radial
and  ulnar arteries,  which are called from their  direc-
tion  recurrents. Among these arteries there is generally
one of considerable size, which proceeds across the elbow
joint near  the internal  condyle.  Sometimes this  is the
ulnar recurrent, which goes up to  anastomose with the
branches of the profunda;  but more  frequently it  is a
separate branch of the HUMERAL artery, which goes
off a little above the elbow, and passes across the articu-
lation, near the internal condyle, to anastomose  with the
branches of the ulnar artery. This artery is denominated
 the Anastomotica.
   There are often other  branches sent off  by the HU-
 MERAL artery; but they are commonly small, and very
 irregular.
   The two great ramifications of the HUMERAL artery
 on the  fore arm have very different directions. The ra-

  * The Profunda sometimes originates from the scapular, or one
 of the circumflex. The profunda minor sometimes has a distinct
 and separate origin, lower down than the other. 
     Course ana Ramifications of the Radial Artery. 257

dial artery preserving the course  of the main  trunk,
while the common trunk of the ulnar and interos-
seal projects from it in a direction downwards and to-
wards the ulna, passing under the pronator teres,  &c.


                The radial Artery,
Passing  over the  pronator teres  muscle, proceeds be-
tween the supinator radii longus and the flexor carpi ra-
dialis, very near to the lower end  of the radius, without
changing its  direction  materially,  being deep  seated
above  and superficial below;  it then alters its course,
and, passing under the tendons of the extensoi s of the
thumb, to the back part of the radius, it continues be-
tween  the metacarpal bones  of the thumb  and of the
index finger, when it  divides into three branches.
   In this course it gives off but few branches. The first
is the Radial Recurrent, which passes upwards and to-
wards the external condyle, and frequently anastomoses
with the ramifications of the profunda humeri.
   The branches which it sends off between the origin of
the recurrent  and the lower end of the radius are gene-
rally very small, and distributed to the parts immediately
contiguous to the  artery. Before it  turns under the ten-
dons of the  extensors of the thumb, it sends a branch
over the wrist towards the  root of the  thumb, from
vvliich  proceeds a branch to anastomose with the volar
branch  of the ulnar;  and another, not so large, which is
frequently continued  on the radial or external side of the
thumb, very near to its extremity. While  the  radial ar-
tery is under the aforesaid tendons, it sends off small
branches to the back of the wrist and back of the hand,
and often to the back of the thumb. Those which are
distributed to the wrist and back of the hand, generally
anastomose with  the small branches of the ulnar and
interosseal arteries.
Vol. II.             2  K 
 258  Origin of the Ulnar and Interosseal Arteries.

   The three branches  into which  the  radial  artery
 divides between the metacarpal bones of the thumb and
 index are, 1st. a branch to the external side of the index;
 2dly, a branch to the thumb, that sometimes divides into
 two which pass up on the anterior or volar surface, and
 sometimes continues, without much diminution, on the
 internal  side of the thumb, near to the end of the last
phalanx;  and, 3dly, a branch,  called Palmaris Profunda,
which dips down into  the palm  of the hand, and, pro-
ceeding in contact with the metacarpal bones, under the
flexor tendons, &c, forms an  arch which extends across
the hand, and often terminates by anastomosis with ano-
ther arch, soon to be described, which is formed by the
ulnar artery.
  This flexure, which is denominated Arcus Profundus,
sends off branches of a very small size, which are distri-
buted to  the bones, ligaments, muscles, &c, contiguous
to it.


 The common trunk of the ulnar and interosseal
                      Arteries
Passes under  several of the  muscles which originate
from the internal condyle,  and  between the flexor sub-
limis and the flexor profundus. Before the Ulnar Recur-
rent goes off from this vessel, the interosseal artery
 often leaves it. This recurrent artery passes  upwards be-
 tween the muscles of the internal condyle, and distributes
 branches among them. It then passes up in the groove
 behind the internal condyle,  and anastomoses with the
 branches of the Anastomotica or  Profunda Humeri.
  The ulnar and interosseal arteries separate from each
 other at the  distance of fifteen or twenty lines from the
 origin of the radial  artery, very near the commence-
 ment of the interosseal ligament. 
Interosseal and Ulnar Arteries.         259
              The interosseal Artery,
 In a majority of cases arises in a single branch from the
 common trunk of the ulnar and interosseal. When it does
 so, the single branch soon sends off the Posterior  Inter-
 osseal artery, which perforates the interosseous ligament,
 and passes down on its posterior surface, while the main
 branch continues on the anterior surface of the ligament,
 and is denominated the Anterior Interosseal Artery.  In
 some  cases the main branch proceeds on the  anterior
 surface as low as  the upper edge  of the pronator qua-
 dratus muscle,  before it sends off  the posterior branch.
 Sometimes the anterior and posterior interosseals arise
 separately.  In this  case the posterior soon perforates the
 ligament.
   The Anterior Interosseal passes  down almost in con-
 tact with the ligament, and gives  branches to the con-
 tiguous parts in its course. It generally perforates the in-
 teroseous ligament near the wrist, and sends off many
 small branches to the back of the wrist and hand, which
 anastomose  with the small branches of the radial and
 the posterior interosseal arteries.
   The Posterior Interosseal soon gives off a recurrent or
 anastomosing branch, and then proceeds downwards to-
 wards  the wrist, sending branches in  its  course to the
 extensor muscles and tendons.
   This vessel sometimes divides into two branches.


                 The ulnar Artery.
   The ulnar artery proceeds among the muscles ob-
liquely downwards, and is not superficial until it has ar-
rived within three  or four inches of the carpus: it then
continues towards  the hand,  sending off very  small
branches in its progress. It passes over the annular liga- 
260       Course of the Ulnar Artery, and

ment at the wrist, and winds round the pisiform bone:
here it is supported by a delicate ligament, which seems
to lie upon it: from this it passes upon the palm of the
hand, under the aponeurosis palmaris,  and over the ten-
dons of the flexors of the fingers. When thus situated, it
forms, in perhaps a majority of subjects, an arch or bow,
called arcus sublimis, which extends across the palm
of the hand, from the ulnar towards the radial edge, and,
after sending branches to  the fingers, &c, from its con-
vex side, terminates near the root of the thumb, by an-
astomosis with that important branch of the radial  ar-
tery, which passes up on the inside of the thumb. The
arcus sublimis almost always sends  off small branches
to the integuments,  &c, on the palm of the hand. It
often sends off, near the root of the metacarpal bone of
the little finger,  a branch  which passes between the
flexor  tendons and the metacarpal bones,  and anasto-
moses with the Arcus Profundus. It then generally sends
off a branch to the inner or ulnar side of the little finger;
and afterwards three branches in succession, which pass
from its  convex side towards the  angles formed by  the
fingers. These are called


                 The Digital Arteries.
When they have arrived near  to the heads of  the first
phalanges of the fingers, each  of these arteries divides
into two branches, one  of which passes along the side of
one of the fingers to its extremity, and the other on the
opposite side  of the next finger:  and in this way they
pass on the sides of all the  fingers, except  the inside of
the little finger and the outside of the index.
   These branches of the digital arteries are called Digito
Radial and Digito Ulnar  arteries, according to  the sides
of  the fingers on which they are placed. They are situa-
ted on the angle, if it may be so termed, which is formed 
     Its Ramifications on the Hand and the Fingers. 261

by  the anterior and lateral surfaces of each  finger.  In
their course from the basis to  the extremity of the finger,
they send off very small transverse  branches, which an-
astomose with each other, especially near the other. Some
transverse  branches  are observable on the posterior as
well as the anterior surfaces. Near the extremity of  each
finger, beyond the insertion of the flexor tendon, the ex-
tremities of  these arteries  ramify  minutely. Some of
these small branches go to the skin, and others anasto-
mose with their fellows of the opposite  side.  Some also
go to the back of the fingers.*

  * The distribution  of the radial and ulnar arteries in the hand, is
very different in different subjects.
  Upon examining a large number of injected preparations in Phi-
ladelphia,  it was found that, is a very small majority of them, the
ulnar artery formed an arcus sublimis, whose branches extended as
far as the ulnar side of the index, and sometimes beyond it.
  That, in near a third of the preparations,  the ulnar artery ramified
without forming an arcus, and supplied  only two of the  digital
branches, viz. the first two on the ulnar side. In such cases the radial
artery generally made up the deficiency of the ulnar, but in a few in-
stances the interosseal was  extended on the palm of the hand, and
 supplied the radial side of the middle finger and the corresponding
 side of the index.
   In a few instances also the ulnar artery was still more deficient,
and the radial was proportionally extended. 
262
Bronchial Artery,
                    SECTION III.

   Of the Branches which go  off between the arch and
          the great bifurcation of the AORTA.

                       PART I.
             In the Cavity of the Thorax.
   THE aorta sends branches  to the Lungs, to the oeso-
phagus, and to the parietes of the thorax.

              The bronchial Arteries
Are the vessels which go from the aorta to the ramifica-
tions of the trachea, and the substance of the lungs. They
are not large, and are very irregular as to number and ori-
gin.
  In a majority of cases the right lung is supplied, in
part, by a branch from the first aortic intercostal of that
side; while the left lung  receives two or three branches
from the aorta directly.  In  some  cases a  large  vessel
arises from the aorta, which divides into two branches,
one of which goes to each lung.
  The bronchial arteries frequently send small branch-
es to the posterior mediastinum, the pericardium, &c.
  Injections have shown, that there is a direct communi-
cation between these vessels  and the  branches of the
pulmonary artery.

              The Oesophageal Arteries
Are very small vessels, which generally arise from the
aorta, but  sometimes are branches of the bronchials or
intercostals that  are spent upon the oesophagus. They
oocur in succession,  and sometimes are live  or  six in 
                  Intercostal Arteries,              263

 number.  They also send twigs to the  contiguous parts,
 and the lowermost often descend to the stomach.

                The Inferior Intercostals
 Are the arteries which proceed directly from  the aorta
 to the parietes of the thorax. Their name is derived from
 their position between the ribs. They are ramified on the
 intercostal muscles and ribs, and on the pleura and some
 of the contiguous parts.  They are called Inferior or
 Aortic Intercostals, to distinguish them from the superior
 intercostals, which are derived from the subclavian artery.
 Their number varies from ten to eight, according as the
 superior intercostals are more or less numerous.
   They originate in pairs on the posterior surface of the
 aorta. The uppermost  of them pass  obliquely upwards,
 and the  lowermost nearly in a horizontal  direction, to
 the lower edges  of those ribs to which they are appro-
 priated. They meet the rio near its tubercle, or place of
 junction with the  transverse process of the vertebra, and
 then proceed  forward, between the internal and external
 intercostal muscles,  in  a superficial but  large groove,
 which is generally to be found on the interior margin of
 the lower surface of the rib.* There is necessarily a differ-
 ence in the length of the right and left intercostals, owing
 to the position of the aorta, which is rather on the left of
 the spine. In consequence of this circumstance,  the oeso-
 phagus is anterior to, and also in contact  with  those of
 the right side.
   They generally  send off an  important branch,  called
 the Dorsal,  which arises near their origin,  and,  passing
 backwards,  sends ramifications to the  muscles  of the
 back. From this dorsal branch also proceeds a  ramifica-
tion, which enters  the spinal cavity, and is spent upon its
membrane and upon the medulla spinalis.
* See Vol. T. page 83. 
264
General Account of the
  After the intercostals, in their progress forward,
have passed beyond the middle of the  ribs, they send off
a branch, which generally proceeds very near to the upper
side of the lower rib. The main trunk generally leaves
the lower edge of the rib when it has arrived within one
third of the length of the bone from  its anterior extre-
mity. It then generally  divides into  several branches,
some of which are spent  upon the pleura, and others on
the intercostal and the contiguous muscles.
  According to the situation of the different intercostals,
some of their ramifications communicate  with those of
the internal and external  mammaries, of the phrenic, the
lumbar, or the epigastric  arteries.
                     PART II.

            In the Cavity of the Abdomen.
  The AORTA  passes into the cavity of the abdomen
between the crura of the diaphragm, as has been already
mentioned. In its course from the  crura to its great bi-
furcation, it sends off one pair of small  arteries, called
Phrenic,  to the diaphragm. Three single arteries,  the
CCELIAC, the  SUPERIOR, and  the INFERIOR
mesenteric,  to  the viscera of the  abdomen. A pair of
large arteries, the EMULGENTS, to the kidneys, with
several that are very small to their appendages;  as  the
Spcrmatics, Capsular, the Ureteric, and the  Adipose. In
addition to these, there is one pair  of small  arteries that
go to the testicles, or to the ovaria and the  uterus, and
four or five pair, called lumbar arteries, that go off
laterally, like the intercostals, to the parietes of the abdo-
men,  and to the muscles, &c, on  the back, which are
contiguous to them. 
Arteries of the Abdomen.
265
               The phrenic Arteries
  Are ramified on the concave surface of the diaphragm,
and are almost always two in number; they are denomi-
nated right and left from their position. They commonly
originate separately from the aorta, but sometimes they
arise in a  common trunk which  soon divides. In some
instances they are derived from the coeliac. In a few cases
the aorta furnishes one, and the cceliac the other. Each of
the phrenic arteries commonly crosses the  crus  of the
diaphragm on its respective side, and proceeding laterally,
in a circular direction,  often ramifies  so as to form an
internal  and external branch. Each of them generally
sends branches to the cardia or oesophagus, to the glandulas
renales,  and other contiguous parts.


                The CCELIAC  Artery
Is the first great branch  given  off by  the  aorta in the
abdomen, and is distributed almost entirely to the sto-
mach, the liver, and the spleen. It projects from the ante-
rior part of the aorta so as to form a right angle with it,
and is of course nearly horizontal when the body is erect.
  The main trunk of this great artery is so remarkably
short, that it has been compared to the stump of a tree:
for at the distance of half an inch from its origin, it ge;
nerally divides into three branches, which pass  to the
stomach, the liver, and the spleen, and are, therefore, de-
nominated the gastric or coronary, the HEPATIC
and the SP LENIC arteries.
  The first  mentioned branch may be called
Vol. II.
2L 
26G
Distribution of
   The superior coronary or gastric arterv,
To distinguish it from other branches, soon to be describ-
ed. It is commonly in the center of the three great rami-
fications of the cceliac, and is also the smallest of them. It
proceeds from its origin to the upper orifice of the stomach
or cardia, and continues thence along the lesser curvature
of that viscus, until it approaches near to the pylorus. In
this course it sends branches to the oesophagus, which
frequently inosculate with the oesophageal arteries. It also
furnishes branches to the cardia, which partially surround
it; and on this account,  the  artery has been  called Co-
ronary.  Some of these last mentioned branches are often
continued on the  great extremity of the stomach,  and
anastomose with those ramifications of the splenic artery,
called Vasa Brevia.
   It continues on the lesser curvature between the laminar
of the small omentum, and sends off successively branch-
es which pass between the peritoneal and muscular coats,
and are distributed to the anterior  and posterior surfaces
of the stomach, communicating with the branches of the
inferior gastric arteries, soon to be described.*


               The HEPATIC Artery
Proceeds  from the great ramification of the cceliac to the
transverse fissure of the liver called the Porta, in which
it generally divides into two  branches.  In this course it
very frequently sends off an artery to the pylorus, which
ramifies  about the small extremity of the stomach, and
often inosculates with some of the branches of the supe-
rior coronary. This branch is called the Pylorica,  and
sometimes it arises from the artery next to be mentioned.

   tThis artery sometimes sends a branch to the liver. When this
is* the case, it is always very large. 
the Coeliac Artery.              267
          The GASTRICA INFERIOR DEXTRA,
Which also generally originates from the main trunk
of the hepatic, but sometimes from one of its branches. It
is an artery of considerable size, which proceeds along the
great curvature of the stomach, from the pylorus towards
the great  extremity, between the laminae of the anterior
portion of the  omentum,  and distributes its ramifications
to both sides of the stomach, and also to the  Omentum. In
its  progress  from the hepatic artery to the stomach, it
sends off branches to the  Duodenum, and to the right end
of the Pancreas.
  The two  great branches  into which the HEPATIC
artery  divides are denominated  right and left, from
the lobes of the viscus,  to which they are respectively
appropriated.  The right  branch is  the largest. Before it
penetrates the  substance of the liver, it sends off a branch
to the gall bladder, called the Cystic Artery.
  The branches of the hepatic artery ramify very minutely
in the liver, as  has been seated in the account of that organ.
  The last great branch of the coeliac is

               The SPLENIC Artery,
Which is generally supposed to be larger than the hepatic
in adults,  although it is less in children. It proceeds in a
transverse direction  from its origin to  the spleen: its
course is  not straight, but meandering or serpentine. It
is situated behind and above the pancreas, and passes
along the groove in the upper  edge  of that viscus. In its
progress,  it sends off many small branches, and one that
is of considerable  size, to the Pancreas. It also sends
one  branch  to the  left extremity of the stomach, which
arises commonly from the main trunk, but sometimes
from the  ramifications, which are soon to be mentioned.
This branch, which is called 
268           Distribution of the Splenic
        The gastrica  inferior sinistra,
Is sometimes, but  not often, very large: Its course is
from left to right. It is situated between the lamina* of the
anterior portion  of  the omentum. It sends some small
branches to the  omentum, and others which are larger
and more numerous, to both  sides of the stomach. Some
of these last mentioned anastomose with the ramifications
of the gastrica dextra, which come from the hepatic.
   When the  SPLENIC artery approaches near to the
spleen, it divides into four, five, or six  branches, each of
which penetrates into that viscus by a  distinct foramen,
and then ramifies in the manner described in the account
of the structure of the spleen.*
   Either from the splenic artery, or from these ramifica-
tions, four or five branches pass to the large extremity of
the stomach, and ramify  there, communicating  with the
vessels already described.—These arteries have received
great attention from physiologists, and are denominated
Vasa Brevia.


        The  SUPERIOR MESENTERIC,
Which is the second great branch given off in the abdo-
men by the  aorta, is not very different in size from  the
cceliac, and  originates about half an inch below it. It is
distributed to the small intestines;  to that portion of the
great intestine, which  is situated on the right side of the
abdomen; and to  the arch of the  colon. From its origin
it proceeds downwards, under the pancreas, and over the
lower portion  of  the duodenum, to the commencement
of the mesentery. When it has arrived between the la-

  * It frequently happens that the splenic artery divides only into
two or three branches, and they subdivide so as to form five or six,
which penetrate the spleen. 
         and the Superior Mesenteric Arteries.     269

minae of that membrane, it descends in a direction which
corresponds with that of the root of the mesentery,* and
forms a gentle curve, with its convexity directed towards
the intestines.  It necessarily diminishes as it  descends,
and generally terminates by anastomosing with one of its
own branches.—This great  artery sends off some very
small ramifications to  the pancreas and the duodenum,
while it is in  their vicinity. It also sends two or  three
branches to the transverse part of the colon, to the right
portion of the colon, to the beginning of the great  intes-
tine, and  the  contiguous portion  of the  ileon. These
branches are commonly termed the colica media, co-
lica dextra, and ileo colica. From the convex side
of the curve, the SUPERIOR MESENTERIC sends off
the important  branches which pass between the lamina
of the mesentery, and supply the Small Intestines. These
branches are numerous,  and  many of their ramifications
anastomose with each other so as to form arches. From
these arches go off other  branches,  which anastomose
again with some of similar origin; and this process  is re-
peated successively several times,  so that a net-work of
bloodvessels seems to be formed on the mesentery. From
the mesentery the small ramifications are continued in
great numbers to the intestines. Some  of them anasto-
mose with each  other on the  coats of the intestine; but
an immense number of minute arteries are continued to
the villous coat, so that, when they are successfully in-
jected, the surface  of  that coat appears uniformly co-
loured by the injection.!

  * See Vol. II. page  114.
  t See the account of the termination of these arteries, at page 104
of this volume. 
270
Distribution of the Inferior Mesenteric.
     The INFERIOR MESENTERIC Artery
Does not go off from the aorta next in order after the
superior mesenteric,  but succeeds it immediately on the
intestines, and continues the arterial ramifications to the
left portion  of the colon, to which the branches of the
superior mesenteric do not extend.
  This artery arises between the origin  of  the emul-
gents,  and the great  bifurcation  of the aorta,  and pro-
ceeds downwards, inclining to the left,  but keeping near
to the aorta. There are generally three branches distri-
buted to  the left portion of the colon,  which  arise from
this  artery,  either separately, or  by a common  trunk
which  soon  divides.  It frequently happens, that one of
these arteries arises  separately, and two by a common
trunk.  These are called the left colic arteries;  and
are  also  sometimes  denominated, from  their position,
superior,  middle, and  inferior.  The superior
generally anastomoses with  that branch of the superior
mesenteric, which is  called  colica media,  and forms
a remarkable  arch,  called the Great  Mesoeolic Arch.
The ramifications of  the other branches frequently anas-
tomose with each other, and are finally spent  upon the
left portion of the colon.
  The main trunk,  diminished by  sending   off  these
branches,  but still of considerable size,  runs downwards
on  the posterior part of the  intestine rectum, between
that intestine and  the  sacrum, where  it  often divides
into two branches, which  continue near to  the termina-
tion of the rectum. From them proceed many ramifica-
tions that are spent upon the rectum.  Some of these ra-
mifications anastomose  with each other, and others with
the ramifications of the haemorrhoidal artery, soon to be
mentioned. 
       Arteries of the Kidneys and Renal Glands.    271


       the EMULGENT or  RENAL Arteries
Are the large vessels which pass from the aorta to the
kidneys. They  arise between  the  superior and inferior
mesenteries,  one on each  side; and proceed in a  direc-
tion which is nearly rectangular to the aorta. The right
emulgent artery is necessarily longer than the left, and it
generally passes behind  the vena  cava. When they ap-
proach near  the concave edges  of  the  kidneys, each
emulgent commonly divides into three or four branches,
which pass into the fissure  of  that organ,  and ramify in
the manner described in the  account of it. Sometimes
two arteries  proceed from the aorta to the kidney: but
this is not a frequent occurrence.


                The Capsular Arteries
Are the small  vessels which  pass to  the glandulae re-
nales.  There are almost  always several of them appro-
priated to  each gland.   They  often arise  on each side
from the coeliac  artery, the aorta, and the emulgent.


                 The Adipose Arteries
Supply the adipose substance surrounding the kidneys.—
There are several of them on each side, and, like the last
mentioned  arteries,  they are very small, and arise from
several sources as well as the aorta.
  The testicles and ovaria arc supplied by  the


                 Spermatic Arteries,
Which are  very remarkable  for their great length and
small diameter.  In a majority of cases these vessels arise
from  the anterior surface of the aorta, a Iktle below the 
272
Spermatic Arteries.
 emulgents:  but it often happens that the left spermatic
 arises from  the emulgent on that side.  They also some-
 times arise from other neighbouring arteries. It has been
 observed when they arise from the aorta, that the origin
 of one of them is generally higher than  that of the other.
   They  pass  downwards, so as to  form an acute angle
 with the  aorta, and  proceed behind  the peritoneum, and
 before the [  soas muscle and ureter.  While this artery is
 in contact with the psoas muscle, it meets with the rami-
 fications  of the spermatic vein, and, in its progress to the
 abdominal  ring,  also joins the spermatic cord.  In this
 course it sends off some very small twigs to the conti-
 guous parts,  and others  that anastomose  with  similar
 ramifications from the mesenteric, epigastric, &c. Before
 it arrives at  the testicle, it divides  into several branches,
 two  of which generally  go to the epididymis, and the
 others penetrate  the  upper and back part of the tunica
 albuginea.


         The Spermatic Arteries in the Female,
 Instead of passing to the abdominal ring, proceed between
the laminae of the broad ligaments, and  send branches to
the ovaria,  which, in some cases, may  be traced to the
 vesicles.  They also send branches to the  fallopian tubes
 and uterus, and to the round ligaments.  Those which are
 on the opposite sides of the uterus, anastomose with each
 other and with the branches of the hypogastric arteries.
  The lumbar regions are supplied  with arteries, which
originate, like the intercostals, from  the posterior part of
the aorta  between the thorax and pelvis. There are four
or five of these vessels on each side, and  they are deno-
minated 
  Arteries above and at the bifurcation of the Aorta. 273


               The Lumbar Arteries:
They pass between the spine and the psoas muscles, and
send branches to the spinal cavity, to the muscles of the
lumbar regions, and the abdominal muscles. They anasto-
mose with the internal mammary, the epigastric, the cir-
cumflex of the ileum, &c.
  A small artery passes off singly from the posterior part
of the aorta at its bifurcation, which  is called


             The Middle Sacral Artery.
It proceeds down the middle of the sacrum to the os
coccygis, and sends off lateral branches, which are spent
upon the contiguous parts, and inosculate with the arterias
sacrae laterales.
                   SECTION IV.

Of the Arteries which originate at and below the Great
              Bifurcation of the Aorta.

            The PRIMITIVE ILIACS
Form an acute angle with each  other.  They proceed
downwards behind the peritoneum, very near the margin
of the pelvis, without sending off any  branch of impor-
tance. At the junction of the sacrum with the ossa ilea,
they divide into  two great branches: the INTERNAL
ILIAC, or HYPOGASTRIC, which  descends into the
pelvis; and the EXTERNAL ILIAC,  which  passes
under the crural arch to the lower extremity.
   Vol. II.              2  M 
 274     General Account of the Internal Iliac.


   The INTERNAL ILIAC, or HYPOGASTRIC,
 Is distributed, in part, to the viscera of the pelvis and the
 organs of generation, and also to the large  muscles ex-
 terior to the  pelvis: it is, therefore, very  large, although
'not quite equal to the EXTERNAL ILIAC.
   It has already been mentioned, that  in the foetal state,
 this vessel appeared to continue in a curved direction
 from its origin to the lower part of the side of the bladder,
 and from thence to the umbilicus, under the denomination
 of the  Umbilical Artery. From the convex side of  this
 curve  the different branches of the internal iliac go off. In
 the  foetal state they are very small in proportion to the
 umbilical artery; but as the artery becomes ligamentous,
 these branches increase in size.
   In the adult, the arrangement of these vessels is very
 different. The  INTERNAL ILIAC generally divides
 into two great branches: the  gluteal, which passes
 through the  sacro sciatic notch, and ramifies  on the ex-
 terior and upper part of the os ileum; and  the ischiatic,
 which passes downwards on the outside of the  tuberosity
 of the ischium.
   The first of these large ramifications passes  out of the
 pelvis above the pyriform muscle, and the last of them
 below it. Several smaller arteries arise from these branches
 near their origin, or from the main trunk of the internal
 iliac, which  are distributed to the different  parts of the
 pelvis; and one important branch of the ischiatic, called
 the pudic,  proceeds downward on the inside of the tu-
 berosity of the ischium.
   The first  of the smaller branches which the internal
 iliac commonly sends off, is called  the 
        Smaller Brandies of the Internal Iliac.      275


                   Ileo Lumbalis:
It sometimes arises from the gluteal  artery, and  some-
times from the main trunk of the internal iliac. It  passes
outwards under the psoas muscle,  and suddenly divides
into two branches. One of them proceeds upwards, and
is distributed in the lumbar region, while the other rami-
fies on the iliacus internus muscle, and is spent  on the
contiguous parts.
  There are also two  or three small arteries called


              Arteria Sacra Laterales,
Which sometimes arise singly, and  sometimes in com-
mon, from the great trunk. They also occasionally origi-
nate from the gluteal artery. These vessels enter  the an-
terior foramina of the os sacrum, to be distributed on the
cauda equina and  the membranes which invest it. Some
of  their ramifications anastomose with branches of the
sacra media and other contiguous  arteries,.
   On the anterior  side of the internal iliac, near the origin
of  the  above mentioned  vessels,  a ligament which was
 originally the umbilical artery,  goes off to the side of
 the bladder, and continues from thence to the umbilicus.
 Sometimes it continues pervious for a short distance, and
 then  small branches pass from it to the bladder.
   In the female it also sends small branches to the uterus
 and vagina.
   In addition to these Vesical Arteries derived from the
 umbilicals, there  are other  branches distributed to the
 bladder, which arise very differently, in different subjects,
 from branches which are soon to be described, as the hae-
 morrhoidal,  pudic, &c.
    From the anterior side of the internal iliac, or from one
 of its great branches, an artery often arises which passes 
276     Smaller Branches of the Internal Iliac.

out of the  pelvis through the aperture in the margin of
the ligamentous  membrane  which  closes  the  foramen
thyroideum of the os innominatum; this is called the


                  Obturator Artery.
This  vessel, while it is in the  pelvis, often sends  small
branches to the bladder and  its appendages, and to the
obturator interims muscle. After it passes out of the pelvis,
it  frequently divides into branches; some  of which are
spent on  the obturator externus,  and the contiguous
muscles, and others go  to  the hip  joint. The origin of
this artery  is variable. Most commonly it arises from the
internal iliac, but often from the ischiatic, and sometimes
from the gluteal.  In  some instances it originates in a way
that  is  particularly  interesting  when the  operation for
crural hernia is to be performed, viz. from the epigastric
artery, soon to be described: for in this case the obturator
artery sometimes nearly surrounds the neck of the hernial
sac*
  A small  artery passes  from the  internal iliac or one of
its branches, to the rectum, which is called the


                 Middle  Hamorrhoidal,
From  its  situation between the branches which are sent
to that  intestine  from  the inferior mesenteric, and those
which go to it from  the pudic.  This artery is spent upon
that part of the rectum, which is above and in contact
with the sphincter. It sends branches to the prostate and
vesiculae seminales in males, and the vagina and bladder
in females.
   In females there is a peculiar artery,

  * See Astley Cooper's great work on Hernia, Vol. I.
  There is reason to believe that this position of the artery occurs
more frequently than has been supposed. 
        Larger Branches of the Internal Iliac.     277


                    The  Uterine,
Which  originates either from the internal iliac, near the
origin of the ischiatic, or from one of it's branches. It
passes between  the laminae of the  broad ligaments to the
cervix  uteri, and  penetrates the  texture of that organ.
The size of this vessel varies with the varying size of the
uterus.


     The gluteal or posterior iliac Artery,
One of  the two great branches of the internal iliac, pro-
ceeds exteriorly through the sciatic notch above the pyri-
form muscle, very near the edge of the bone. On the out-
side of the ilium it generally divides into two branches,
one of which ramifies between  the gluteus medius and
minimus, and the other between the medius and maximus.
It is principally spent upon these muscles, and sends
branches to the contiguous parts.


               The ischiatic Artery,
The other great branch of the internal iliac, passes through
the sciatic notch below the pyriform muscle, and proceeds
downwards, between the great trochanter of the os femoris
and  the tuberosity of the ischium, under  the gluteus
maximus muscle. Soon after its origin, it commonly sends
off a considerable branch, the Arteria Pudica, which also
passes downwards:  it then continues its course as above
mentioned, and its principal branches are distributed to
the gluteus maximus and the muscles of the upper and
back part of the thigh, while its smaller branches go to
the os  sacrum and coccyx, and  the contiguous small
muscles. 
278                 Pudic Artery.
               The pudica interna,
As has been just mentioned,  is often  a  branch of the
ischiatic artery, but  sometimes originates  immediately
from the internal iliac. It proceeds downwards and in-
wards,  diverging from the ischiatic, and passing between
the two sacro sciatic  ligaments to the interior side of the
tuberosity of the ischium,  whence  it continues  on the
inside of the crus of the os ischium and pubis until it
approaches the symphysis, when it generally divides into
three branches,  which are spent upon the organs of gene-
ration,  from which circumstance the name of  this artery
is derived.
   One or more branches from it also  pass to the lower
part of the rectum and sphincter  ani, and are called the
Lower Hamorrhoidal Arteries.
   In its course  it sends off many small branches to the
contiguous parts; one of which, called the Perineal, leaves
it near  the transvcrsus perinei muscle, and  passes between
that muscle and  the  skin, and between the bulb of the
urethra and the  crus of the penis, to the scrotum.
   When the pudic  has arrived near the bulb of the
urethra it sends a branch into it, which is continued into
the corpus spongiosum urethrae, and ramifies there mi-
nutely.
   At the symphysis  of the pubis, it sends off a second
branch, which passes to the back of each crus, and, pro-
ceeding along it, parallel to its fellow, terminates in the
glans penis: in this course it sends branches to the elastic
coat, to the integuments, and to the  prepuce. This vessel
is called the Arteria Dorsalis.
   The main trunk of the pudic artery then penetrates the
corpus cavernosum, and proceeds through it in a straight
direction.  Its  ramifications  appear to  be  distributed
through the internal structure of the corpus cavernosum, 
   External Iliac. Branches of the External Iliac.  279

and some of them extend through the septum to the other
side, while others pass to the corpus spongiosum urethrae.


             The EXTERNAL ILIAC,
The great artery of the lower extremity, appears  soon
after birth, like  a continuation of the primitive iliac, and
proceeds along  the brim of the pelvis  behind the  peri-7
toneum, to Poupart's ligament or the crural arch, under
which it passes.
   The psoas muscle is at first in contact with it on the
outside, and the internal iliac vein on  the inside.  As it
passes under Poupart's ligament, it is immediately  ante-
rior to the psoas and iliacus internus muscles where they
are united, and  the crural nerve is exterior to it. Before
it arrives at the lower edge of Poupart's ligament, it  sends
 off


                The Epigastric Artery,
Which  arises on  its internal side, and proceeds down-
wards and inwards about half an inch,  then it turns up-
wards and inwards,  and continues in that  direction for
 a small distance, after which its course  is less oblique. It
 passes between  the peritoneum and the abdominal  mus-
 cles, behind the spermatic cord, and the round ligament
 in females.
   It generally changes its oblique direction after passing
about two inches, and then proceeds in contact with the
 rectus, and very near its external edge. Its ramifications
 are expended upon  the anterior parietes of the abdomen;
 and, after it has arrived as high as the umbilicus, it com-
 monly divides into branches, which often inosculate with
 the ramifications of the internal mammary.*

   * Several respectable surgeons have  been taught by experience,
 that when the abdomen is distended by ascites, the position of the 
280     General Account of the Femoral Artery.

  An artery, which is  rather smaller than the epigastric,
arises nearly opposite to it, but  rather lower, from the
external side of the external iliac. It is called


        The  Circumflex Artery of the Os Ilium,
And proceeds upwards and outwards to the upper margin
of the os ilium, along which it continues very near to the
spine. It is distributed principally to the abdominal mus-
cles, to the iliacus internus and the  psoas, and the parts
contiguous.
  The artery of the lower extremity, after passing under
Poupart's ligament, takes the name  of


                FEMORAL Artery,
And proceeds downwards in a direction  so spiral, that
although it is in front at the upper part of the thigh, it is
completely behind at the lower part. It sends branches to
the muscles of the thigh, as the aorta does to the viscera
of the abdomen, viz. by a few large vessels which extend
and ramify to a great distance among them.
  The situation of the adductor muscles, and their attach-
ment to the os femoris, is such, that  the  artery in this
course must  necessarily perforate their common tendon,
which it does at the distance of one third of the length of
the bone from its lower end.  The aperture in this tendon
corresponds  precisely  with the  general  course  of  the
artery; and before the artery enters this perforation,  it
is on the internal side of the bone; after it has passed the
perforation, it is on the posterior side of it. After passing
through the  tendon of  the adductors, it is denominated

epigastric artery is so much altered, that  it will sometimes be found
in the middle of the oblique line, which extends from the umbilicus
to the superior anterior spine of the ileum. 
 Profunda and Circumflex branches of the Femoral. 281

The Popliteal Artery, and it retains this name until it
divides.
  It then proceeds downwards, being very near the bone,
and between the tendons of the flexors of the leg, covered
by the great nerve of the lower extremity, and very often
also by the  vein.  After crossing  the articulation of the
knee, when it  is between the heads of the gastroc nemii
muscles, at  the  lower edge of the popliteus muscle, it
divides into  the anterior tibial and the common trunk of
the peroneal and posterior tibial arteries.
  The FEMORAL artery, soon after emerging from
Poupart's ligament, sends off very small branches to the
inguinal glands, and other contiguous parts. It also sends
off the


                  External Pudics,
Which are two or three small arteries that are generally
spent upon the Scrotum in males and the Labia Pudendi
in females.
  About two inches below Poupart's ligament, the great
branch which has been called the muscular artery of the
thigh, leaves it. This vessel is commonly denominated


               ARTERIA PROFUNDA.
It arises from the back part of the trunk of the femoral,
and passes downwards and backwards, in a way that has
been compared to the separation of the internal iliac from
the external.  Very soon after its origin, it sends  off two
branches,  which proceed, one on the internal, and  the
other on the external side of the thigh, and are called the
circumflexa  interna  and externa. It then passes down-
wards  behind  the  trunk of the  femoral, and sometimes
  Vol. II.              2 N 
 282  Branches of the Profunda and the Femoral.

 very near it, on the adductor muscles, and finally divides
 into branches, which are called the Perforating.


              The External Circumflex
 Sometimes arises from the femoral, but most commonly
 is a branch of the  profunda, as above stated. It passes
 under the rectus and tensor vaginae femoris towards the
 great trochanter, and generally divides into two branches,
 one of which continues in the-transverse direction, and
 sends branches to the upper and back part of the  thigh,
 and the parts contiguous to the joint; while the other de-
 scends in the course of the rectus  femoris muscle, and
 some of hs ramifications extend near to the outside of the
 knee.


               The Internal Circumflex
 Is often smaller  than the other.  It  generally passes be-
 tween the psoas and the pectineus muscles, and continues
 round the thigh towards the lesser trochanter. Its ramifi-
 cations are expended on the upper portions of the adduc-
 tor muscles and the muscular parts contiguous  to the
 lesser trochanter. It also sends branches to the articulation.


              The Perforating Arteries
 Are two or three ramifications of the  profunda,  which
 pass through the adductor  muscles, and  are expended
 upon the flexor muscles on the back of the thigh. Some
of the terminating branches of the profunda itself are also
called perforating arteries.
  The next branch of importance which is sent off by the
FEMORAL artery, leaves it before it enters the aperture
in the tendon of the adductors, and is called 
Branches about the Ham.
283
               The Anastomotic Artery.
 This vessel soon  inclines  downwards.  Its ramifications
 extend into the vastus internus muscle; some of them
 follow the tendon of the adductors, and ramify about the
 internal condyle.
   Several  small branches go off  from the great artery
 soon after it passes through the tendon of the adductors,.
 which are distributed to the contiguous muscles. Some
 of them are also called


                 Perforating Arteries.
 Among them is the principal medullary artery of the o$
 femoris.
   In the ham, the  great vessel there called


                   POPLITEAL,
 generally sends off several small branches.  Two of them
 go off on the inside, one above and the  other below the
 knee; and two on the outside in the same manner. They
 are named, from their situation, The Superior and Infe-
 rior  Internal, and  The Superior and Inferior External
 Articulary Arteries.
   The Superior Internal artery perforates  the tendon of
 the adductors above the internal condyle, and ramifies
 minutely on the inner side of the joint.
   The Superior Externalartery passes through the lower
 portion of the biceps above the  external condyle, and ra-
 mifies minutely on the outer side of the joint. Its superior
 ramifications  anastomose with  those of the descending
 branch of the external circumflex, while its inferior rami-
 fications communicate with  those of the corresponding
artery below. 
284
Arteries of the Leg.
  The two inferior arteries  originate nearly opposite to
the middle of the joint, and pass downwards.
  The Inferior Internal artery passes under the internal
head of the gastroc nemius muscle, on the posterior and
internal side of the  head of  the  tibia. Its ramifications
communicate  with  those of the  corresponding artery
above and of the tibialis antica. Below they also extend
to the interior  of the joint.
  The Inferior External artery passes under the external
head of the gastroc nemius and the plantaris muscle, and
continues under the external lateral, and the capsular liga-
ment.  It is distributed on the external and inferior part
of the articulation, and  sends also some branches to the
interior of the  joint.
  There is frequently an azygous vessel, called the Middle
Articular artery, which arises from the back of the popli-
teal, and  is distributed to the posterior parts of the arti-
culation.
  The POPLITEAL  artery, after this, sends off a  few
small branches to the heads of the muscles of the leg, and
among them one of considerable  length, to each of the
heads  of the gastroc  nemii. At the under edge of the
popliteus muscle, it sends off horizontally a large branch
which passes directly forward between the tibia and fibula,
above the commencement of the interosseous  ligament.
After this it continues to descend,  nearly in the same di-
rection, under the soleus muscle, behind the tibia;  but
before it has  proceeded further than twelve or fifteen
lines, it  sends off a branch which forms an acute angle
with  it,  and approaches near the fibula, along which it
descends.
   The branch sent off anteriorly, is called the  anterior
 tibial  artery.
   The main trunk, which continues downwards, is called
 the posterior tibial artery; 
Anterior Artery of the Leg.
285
  And the branch which descends near the fibula is called
the Peroneal or Fibular artery.


           The  anterior tibial Artery,
After its  arrival on the anterior part of the leg, passes
down close to  the interosseous ligament, with the tibialis
anticus muscle on the inside, and the extensor communis
on  the outside, in the first part of its course; and after-
wards, with the extensor pollicis pedis on the outside of
it.  It gradually inclines internally as it descends, so that
a little above  the ankle it  is upon the  front part of the
tibia. It proceeds thence with the tendons of the extensor
digitorum pedis, under the annular ligament, to the upper
surface of the  foot, on which it continues to the interstice
of the first and second metatarsal bones, where it descends
to anastomose in the way presently to be mentioned.
  In  this course it  sends off, soon after it has arrived at
its anterior situation, a recurrent branch, which is distri-
buted to the heads of the muscles and the ligaments of
the articulation, and which anastomoses with the branches
of the inferior articular arteries. It also sends off, on each
side, many arterial twigs to  the contiguous muscles, and
very frequently  one branch of considerable size, which
passes down near the fibula.
  When it has arrived near the end of the tibia, it sends
a branch on each side, called the Internal and External
Malleolar. On the top of the foot, among several  smaller
arteries, it sends off a branch under  the extensor  brevis
digitorum pedis, which passes  outwards and forwards,
and supplies the muscles, &c, on the upper part of the
foot.  This vessel is called Arteria Tarsea.  There is also
another branch, called Metatarsea, which generally arises
about the middle of the foot, and passes  obliquely out-
ward and forward, supplying the contiguous parts.
  The anterior  tibial  artery, having arrived at the 
 286     Posterior Tibial and Peroneal Arteries.

 space between the metatarsal bones of the first and second
 toes, bends down  to the sole of the foot, but previously
 sends off a branch which passes near the external edge of
 the metatarsal bone of the great toe, and divides into two
 branches, one of which goes to the outside of the great
 toe, and the other  to the opposite side of the toe next to
 it.


           The posterior tibial Artery,
After sending off the anterior tibial, parts with the Pero-
neal or Fibular, as has been already stated, and then con-
tinues on the back of the tibia, behind the internal ankle,
fc) the sole of the foot.


            The Peroneal or  Fibular Artery
Is not commonly  so  large as  either of the two other
arteries of the  leg, nor is it so constant. It passes down
very near the internal  edge of the fibula. It is in contact,
for some distance,  with  the tibialis  posticus muscle, and
is anterior to the soleus and the flexor pollicis longus; it
sends branches to the contiguous muscles.  After it has
passed along two  thirds of the length of  the  fibula, it
frequently, but not always, divides into an anterior and
a posterior branch.
   The anterior peroneal soon perforates the interosseous
ligament, and passing down some distance on its anterior
surface, continues  to the ankle and upper surface of the
foot. It gives ramifications to all the contiguous parts in
its progress, and anastomoses with some of the small ra-
mifications of the tibialis antica.
   The posterior peroneal branch is the continuation of the
main trunk.  It passes behind  the external malleolus, and
ramifies upon the external side  of the foot.
   The posterior tibial artery passes down, inclining 
Arteries of the Foot.
287
rather  obliquely  inwards, between the gastroc nemius
internus, which is posterior to k, and the tibialis posticus
and flexor digitorum, which are anterior to it. Upon the
leg it gives off many small branches, one of which, termed
the Arteria Nutritia Tibia, comes off high up,* and, after
ramifying as it descends, sends a branch to the medullary
foramen of the tibia.
   At the lower part of the leg the posterior tibial is
situated rather superficially between the  tendo Achillis
and the tibia. It proceeds thence behind the internal ankle
in a deep situation, covered by an annular ligament, and
passes between the abductor muscle of the great toe and
the bones of the tarsus. It then divides into two branches
—the internal and the external plantar arteries.


              The Internal Plantar Artery
Is commonly  much  smaller than  the other ramification.
It passes in the direction of the internal edge of the foot,
but at some distance from it, and  often lies between the
aponeurosis plantaris and the abductor pollicis.  It fre-
quently terminates by anastomosing with  one of the arte-
ries of  the great toe, and in its course sends off several
branches to the contiguous parts on each  side of it.


             The External Plantar Artery
Is the continuation of the main trunk. It proceeds out-
wards and forwards between  the short flexor of the toes
and the flexor accessorius; and continues afterwards be-
tween the  first of these muscles and the abductor of the
little toe. At the  metatarsal bone of the little toe it begins
to curve,  and continues  its curvature across  the other
metatarsal bones to the interstice between the great toe
• This artery sometimes comes off from the popliteal. 
288
Arteries of the Foot.
 and the one next to it, passing between the tendons of the
 long extensor and the metatarsal bones. At  the interstice
 above mentioned, it anastomoses with the tibialis antica.
 The curvature, thus formed, is called the Arcus Plantaris.
   In this course, the External Plantar sends off several
 branches to the heel and the parts of the foot, especially
 on the external side; the deep seated parts of the foot be-
 ing supplied from the curve.
   Digital branches go off  from the  curve, as they do in
 the hand, from the curve  of  the  ulnar. There is  first a
 small branch to the outside of the little toe; and then three
 regular branches, which pass to the junction of the roots
of the four small  toes,  and  divide, like the digital arteries
 of the hand, so as to send a  branch to the side of each toe.
 These digital arteries  pass between the muscle  called
 Transversalis Pedis and the metatarsal bones. Near the
heads  of these bones, each of them generally sends off
two arteries  that pass upwards  between the  interossei
muscles and the bones, and anastomose with the ramifica-
tions from the top of the foot.
  The External Plantar, soon after  sending off the third
digital artery, anastomoses with  the  anterior tibial, and
then continues to the junction of the root of the great toe
with the one next to it, when it divides into two branches,
which go to the opposite sides of those toes.  In its course
it also sends a branch to the internal side of the great toe. 
A     TABLE
To face page 297-1
EXHIBITING  THE DISTRUJUTION OF  THE BRANCHES  OF THE  AORTA.
) coaoxARi Arteries
which are spent upon the substance of the Heart.
  The COMMON TRUNK
Of the Right Subclavian and
   Right Common Carotid.
At the Curvature,  <
The carotids are appropriated
  the head. They proceed
  the side  of the trachea,  and <
  divide at the upper edge of
  the thyroid cartilage, into
The EXTERNAL CAROTID,
  which is principally uppropri-  j
  ated to the exterior of the  i
  head, and the  upper parts of
  the neck.   It gives off
The INTERNAL  CAROTID,
  which is Appropriated to the
                      J The Tongue.   Sublingual  Gland.   The Pha


The Facial

„.,  , r  .   „.        ,  C The Pharynx and contiguous parts.
1 l.e Inferior Pharyngeal  JThe ^J „f the Cratllum.

The Occipital      -      The posterior part of the Cranium externally.
„  „           .  .    C The cavity of the Tympanum.
The Posterior Auricular  J pwt8 com'igllous to t|ie external Ear.

                      ("The  Superior and Inferior Maxillary bones.
                      ) The  Fauces.  The  Pterygoid muscles.  The
The Internal Maxillary   -i Pukte   Tll€ Dura Matcr.  The Interiorof the


                      c The anterior and lateral parts of the Cranium,
                      £  externally.
The Temporal
The Ophthalmic Artery, to the Eye and its appendages.

The  An
7%e LEFT SUBCLAVIAN.
Each of the Subclavians is the first portion of the great artery of the
  Upper Extremity of its respective side.
It gives off*
The snoTtrniiLar
The Oesophageal
The mm
The Phremt Arteries  ■
CCELIAC ARTERY
SUPERIOR MESENTERIC
Capsular Arteries -
EMULGENTS
Spermatic* -
                  f" Anterior portion of
The  Internal  Mam-}   parietes of the T
  miry, to the      £   ny   -
                  rCerel
The Vertebral to the J   tcr
                      :rcbellum.  The pos-
                       rior portion of the
                      ,.orebrum.
The Inferior Thyroid $ Thyroid  Gland    Tra-
      t0 the        I   <!*■■  (Esophagus.
The  Superior Inter- S S'
v of the Intercostal
The Cervical,
i the
5M^.^"";.
The Sca|
To the Trachea and substance of the Lungs.
To the OZsophagm
           rM„.ti.:„ftl1rNcek.
iidarv  tolhesDu  »n the tlorsum of
           C  Ih*: Scapul:.
  The AXILLARY
Is the next portion of
  the artery  of the
  upper extremity. It
  gives off
The Thoracic and the External
  Mammary arteries.
To the Pectoral and other mus-
  cles on the anterior part of the
  thorax and shoulders.

    The Scapulary Arterj'i
To the muscles about the sca-
  pula and  the posterior part of
     The Circumflcxac,
To the parts about the upperend
 'of the Os Humeri.
 The Profunda Humeri
         and
   Profunda Inferior,
 To muscles on the Os
        Humeri.

The  Anastamotica to an-
 astomose with an artery
 from below, and to the
 muscles.

At the Elbow it gives off
The ncwaoisxAj;
 The curai

which send off
  Branches to the  muscles in it

1  A recurrent branch.
  A branch to the thumb.
  To the rulial side of the index.
  To the arcus profundus.
The arcus sublimis in the palm of
  the hand, which sends t>F the
  digital arteries to the side* of
  the fingers.
N B.  The ImeroMtal and ihe Dinar
 come off from Uw Humeral, br a cam-
           n of the lower intercostal spaces.
To the diaphragm.
To the stomach, liver, and spleen.
Almost all the small intestines, and part of the great.
Glandule Renales.
The Kidneys.
The Testicles.  The Ovaries.
The left portion of the Colon, and the Rectum.
Muscles on the loins and the abdomen.  The spine and the spinal canty .
Which is spent upon the Sacrum, Coccyx,and Rectum.
At the great Bifurca- <
  The PRIMITIVE ILIACS,
One of which is divided on each
  side of the Pelvis into
Tke Itio Lumbar artery t
  The  EXTERNAL ILIAC,
The first portion of the great
  artery « the lower extremity, t
  which passes under Poupart's
  ligament to the thigh, but pre*
  viously Mods off
  TThc Sacrum, internally and  ex
to<  ternally.
  (The Cauda Equina.

  f The Bladder.
to< The Uterus.
  (The Rectum.

  r The Muscles on the upper and
to< interior part of the thigh.
  (The llipjoint, &c.

  r The Muscles on the lateral and
to <  posterior parts of the Ossa In-
  CTIie M»
,o \  and t
  C  thigh
the posterior part <
(Which is often give
   by the Ischiatic.)
i offCThe Organs of Generation
  The CiratmJUxa I&i,
A small artery, which ■>
  spent upon  the iliacus
  abdominal muscles and
  the psoas.

    The Epigastric,
Which is spent upon the
  muscles,  and integu-
  ments of the anterior
  part of the abdomen.
  The FEMORAL

The  second portion
  of the great artery
  of the lower extre-
  mity begins at Pou-
  part's ligament. It
 The External Pudic
To the exterior parts of
  the Organs of Geue-


    The Profunda,
And its  branches, the
  two circumflex*, to
  the muscle* on the
  thigh.
  The POPLITEAL,
The third  portion of the
  great artery, lies on the
  back of the thigh.
It sends  off the articular
  arteries, which anasto-
  mose with each other,
  and supply the contigu-

It divides into
   The A.tTxaion tibial,
Which proceeds down the an-
  terior part of the leg to the '
  top of the foot, from which
  it descends to the  sole.  It
  sends off
      Thei
Which is near the fibula on the
  posterior side of the interos-
  seal ligament.  It is  spent
  upon
   i and the internal ankle
lo'the sole of the foot, where
it 'divides.  It sends off
A  recurrent  branch  to anasto-
  mose  with  branches  from

Branches to the anterior muscles
  of the leg.
Tarsal and metatarsal branches
  to the upper part of the foot.
The muscles on the outside of

The ankle and the outside of the
Branches to the muscles.
The  medullary  artery of the
  tibia.
The internal and the  external
  plantar arteries, to the parts
  on the sole of the foot and the
  toes.

N B The Potterior Tibial and the Pe-
  roneal came off frwn Um PapUtcal by 
 
289
                    CHAPTER III.


     OF THE PARTICULAR DISTRIBUTION OF THE VEINS.

ANATOMISTS of great respectability have very dif-
ferent sentiments respecting the best method of describing
the veins.  Some of them, in order to  follow the course of
the circulation, commence with the small veins, and pro-
ceed to the,large trunks which are formed by their union.
Others begin with the great veins that empty  into  the
heart, and  proceed from them to the small ramifications
of the venous system, in a  direction the reverse of  the
circulation.
   As the last method is the easiest for the student of
anatomy, it will be adopted here; but it must always be
kept in mind, that the blood flows from the small veins
into the larger, and not from the latter  into the former,
as the mode of description seems to  imply.
   The great trunk of the venous system differs consi-
derably from that of the arterial with respect to its con-
nexion with the heart; for it communicates with that organ
in such a manner that, when  viewed  from before, it  ap-
pears like  two vessels; one opening  into the  upper,  and
the other into the lower part of the right auricle. When
viewed from behind, it appears like a  continued tube,
three fourths of which are deficient anteriorly; and to the
margin of this deficiency the right sinus or pouch of the
heart is connected.
   In some preparations of the heart, where all the great
vessels connected with it are much distended by the in-
jection, and the pulmonary vessels are injected  first; the
right  auricle is so much pressed upon  from behind, by
   Vol. II.             2  O 
290
Feins of the Heart.
the vessels which go to the right lung, that the direction
of the superior and inferior portions  of the vena cava,
which thus communicate with it, is altered.  Each of them
is turned  obliquely forwards, so that  it forms an angle
with the other. This occasions them to appear more like
distinct vessels than they otherwise would do.
  The above mentioned  portions of the great  veins are
denominated the Superior or Descending, and the Inferior
or Ascending Vena Cava; as if they were perfectly distinct
and unconnected  with each other.


                The coronary Veins,
Which are exclusively appropriated to the heart, may be
considered here,  as they  are not included in the general
arrangement of the veins.
  The great vein of the heart begins at the lower part of
the right auricle,  very near to the septum, which divides
the two auricles.  It soon  proceeds to the left, in a circular
direction, surrounded with  adipose matter, in the  deep
groove  which exists between the left auricle and the left
ventricle.  It continues  between the  auricle  and  ven-
tricle, until it is immediately  over the septum,  which
divides the two ventricles.  Here its direction changes,
and it proceeds to the apex of the  heart, where its small
ramifications anastomose  with others soon to be described.
In its course rota nd thebasis of the left ventricle, it sends off
several branches, one of which is considerable, that pro-
ceed  from the basis towards the apex of the heart,  rami-
fying on the surface of the left ventricle.
   A  second vein, much less than the first, appears to pro-
ceed  from the great vessel at its commencement,* and
continues on the  lower flat surface  of  the heart, between
the two ventricles, to the apex, accompanied by a branch
* It often opens into the auricle by a separate orifice. 
      Superior Vena Cava and its Great Branches.  291

of the right  coronary artery. This  has been called the
Middle vein of the heart.
  In addition to these there are several veins which begm
at the- right auricle, and extend on the surface of the right
ventricle towards the apex of the heart.  These have been
called the Anterior Veins.
                     SECTION I.

   Of the SUPERIOR or DESCENDING  VENA
    CAVA, and the Veins which communicate with it.
   THIS great vessel proceeds upwards from the superior
 and posterior part of the right sinus or pouch of the heart;*
 and a portion of it is so involved by the pericardium, that
 it seems to be  included in that sac, as the heart is in diis
 situation. It is  somewhat  anterior as well as to the risrht
 of the aorta. It  continues above the pericardium, adhering
 to the right lamina of the mediastinum, and rather inclining
 forward.  When it is as high  as the lower margin of the
 upper rib, it sends off a very large branch, which conveys
 the venous blood of the left arm and the left  side of the
 head and neck. This large vein, which is very important,
 both on account of its size and its situation, proceeds in a
 transverse direction within the sternum, almost in contact
 with and but little below  the upper and  internal margin
 of that bone. Immediately behind or within the origin of
the left sterno-mastoid muscle, it divides into the left sub-
clavian, which preserves a transverse course, and the left
internal jugular, which proceeds to the cavity of the
cranium by the foramen, lacerum.

   *Sec the description of the  heart, in page 50, of this volume. 
292          ,      Vena Azygos.

  After sending off this transverse branch to the left, the
great vein continues upwards and behind the right sterno-
mastoid muscle, and there sends off, nearly at right angles,
the right subclavian vein. After it  has parted  with this
vein, it takes the name of Internal Jugular, and continues
to the right foramen lacerum, in the basis of the cranium.
—The superior vena cava is, therefore, principally formed
by the union of the subclavians and internal jugulars from
each side of the  body.
  Immediately after the superior cava rises above  the
pericardium, before it divides as above stated, it sends off,
from its posterior part, a large vein which is single, and
therefore called


                    VENA  AZYGOS.
  This vessel projects backward above the right pulmo-
nary artery and right branch of the trachea, and then curves
downwards behind them. It  proceeds  down the spine to
the right of the aorta and at a small  distance from it, into
the abdomen, between the crura of the diaphragm, and
sometimes between some of the portions of that muscle,
which are attached to the dorsal vertebrae. In the abdomen
it often anastomoses either with the lumbar veins or the
vena cava.
   The  azygos frequently sends  off several small veins
from its curvature to the contiguous parts, and also the
right Bronchial Vein, which passes along the ramifications
of  the  trachea  into the substance of  the lungs.* In its
course downwards it gives off branches to the oesophagus,
some of which are considerable.
   The Inferior  Intercostal Veins originate directly or in-
directly from  the azygos. In some cases there is no Su-
perior Intercostal on the right side; and then the two or

   * This bronchial vein sometimes arises from the superior cava. 
Inferior Intercostal Veins*           293
three uppermost of the right intercostals are also derived
from the azygos; and often originate from it by a common
trunk, which soon divides.
   Most  commonly the ten inferior intercostals  on the
right side proceed directly from the azygos, and  accom-
pany the intercostal  arteries.  Their  posterior branches
pass into the vertebral cavity, and communicate with the
veins which are there.
   About the sixth or seventh  rib, the  vena  azygos fre-
quently sends off a branch to the left which descends on
the left side of the vertebrae, and sends off those Lejt in-
tercostal  veins which are  below its  origin. It passes
through  the diaphragm with the aorta, or to the left of it,
and anastomoses either with the azygos itself, or in a way
which is analogous to the anastomosis of that vessel.
   The vena azygos may be regarded as the great trunk
of the  veins of the parietes of the thorax,  which are thus
collected, because they could not with convenience pass
singly to the vena cava, as the  arteries do to  the aorta.
   Soon  after  sending off the vena azygos, the Superior
 Cava sends off the great transverse branch above mention-
ed. From this it continues upwards but a short distance,
when it divides, behind the right sterno mastoid muscle,
into the right subclavian and right internal jugular.
   The branches of the superior  cava,  which thus inter-
vene between the great trunk and the subdivisions behind
the sterno-mastoid muscles, are often called the Subclavian
Veins; but they do not appear to be accurately named.
For,  1st, they are not situated under the clavicle, and,
2dly, they are the common trunks of the subclavians and
internal jugulars united.
   There  is a difference in  the places where  some of the
smaller veins originate on each side. The internal mam-
mary and the  inferior thyroid, on the right side, arise
from the superior  cava,  or from the subclavian at its
origin. On the left side they arise from the subclavian. 
294
Superior Intercostal Veins.
         The superior  intercostal Veins
 Are somewhat different on the two  sides.  That  on the
 right is often the smallest and the least extensive. It com-
 monly originates from the posterior and inferior part of
 the subclavian opposite to the origin of the vertebral, and
 is generally distributed to the first and second intercostal
 spaces, but rarely to the third.
  The Left Intercostal frequently originates near the left
 internal mammary, and sometimes in  common with it. It
 descends behind the aorta, on the  left of the spine,  and
 commonly  sends off the six  upper intercostal  veins,, of
 which the two or three superior pass upwards from a part
 of the vein which is opposite to the third dorsal vertebra.
 Its extent is very different in different subjects. In some
instances it passes so  low as to supply the seventh or
eighth intercostal space. This vein  also gives off the Left
Bronchial Vein, which  sends branches to the oesophagus
and bronchial glands.


               The vertebral  Veins
 Arise from the subclavians, but sometimes they proceed
differently in different Subjects: the right passing behind,
and the left before, the subclavian artery of its respective
 side. Each  of them, however, becomes contiguous to its
corresponding artery. When it has  arrived at the place in
the transverse processes, where the artery enters the ver-
tebral canal, it sends off an external branch, which passes
up,  before  and nearly in contact with, those processes,
and gives ramifications to the contiguous muscles, and
also to  the cavity  of the  spine. These last mentioned
ramifications enter by the lateral apertures between the
transverse processes, and anastomose  with the veins and
sinuses of the cavity. The branch often finally terminates 
Vertebral Veins.
295
 in the lateral sinus of the dura mater, by passing through
 the foramen  near the  mastoid process of the temporal
 bone. The Main Trunk of the vertebral vein generally
 sends off another external branch to the muscles near the
 basis of the neck, and  afterwards  enters the canal with
 the vertebral artery. While in this canal, it generally sends
 off two branches through each of the lateral apertures be-
 tween the vertebrae. One of these  branches passes back-
 wards to the muscles of the neck; and the other proceeds
 into  the great  spinal cavity, and communicates with the
 venous sinuses.
    When it has arrived at the atlas, the vertebral vein
 sends branches to the contiguous muscles of the neck. It
 also  frequently sends a branch through the posterior con-
 dyloid foramen of the occipital bone to the lateral  sinus.
    It is evident, from these circumstances, that the verte-
 bral  vein carries a portion of blood from the sinuses of
 the brain and  of the spinal marrow, as well as from the
 muscles of the neck, into the subclavian veins.
    The veins of the head are  frequently very  different in
 different subjects.


            The INTERNAL JUGULAR,
, Already  mentioned, is  often almost exclusively  appro-
 priated to the  cavity of the cranium: and all the exterior
 veins of the head are ramifications of one or more smaller
 vessels, which pass up superficially on the neck, and are
 denominated External Jugulars. In some instances almost
 all the exterior veins of the head are united to the internal
 jugular  at  the upper part of the  neck, and it of course
 conveys  the blood of the exterior as well as of the interior
 parts of the head. Frequently these veins are  divided be-
 tween the  internal and external  jugulars, but they are
 divided very differently in different subjects.
    The Internal Jugular, however, almost always  passes 
296             The Internal Jugular.
»  in the same direction from the inside of the origin of the
  sterno-mastoid muscle to the posterior foramen lacerum
  of the cranium. It is deeply seated on the external side of
  the common carotid artery, and under the sterno-mastoid
  muscle. Between  the upper margin of the thyroid car-
  tilage and the angle of the lower jaw, it often sends off
  branches which are very different in  different subjects,
  but commonly pass to the anterior parts of the neck and
  face: above these  it generally sends another  to commu-
  nicate with  the external  jugular.  One of the branches
  which often go off from the internal, jugular is that which
  corresponds with the superior thyroid or laryngeal artery.
  This  vein,  which  has sometimes been called the Gut-
  tural, sends many ramifications to the thyroid gland. The
  Ranular veins,  which are  so conspicuous  under  the
  tongue, arc also  derived from U; and  it likewise sends
  branches to the larynx and pharynx.
     Before the internal jugular enters the foramen lacerum,
  it suffers a partial dilatation, which is generally larger on
  one side than the other.*  This  dilatation occupies the
  fossa at the foramen lacerum.  After passing through the
  aforesaid foramen, the internal jugular terminates in the
  lateral sinuses of the  dura  mater, f These and the other
  sinuses within the cavity of the cranium are important
  portions of the venous system, which  are interposed be-
  tween the smaller  branches spread upon the pia  mater

     * When the veins of the nerk are injected it very often appears
  that a considerable portion of the internal jugular is much larger on
  one side than the other, as if it were affected  with varicose disten-
  tion.
     It also often appears that the general arrangement of the exterior
  vein is different on the two sides of the head and neck.
     fit  is averted that the internal coat, or lining membrane of the
  internal jugulars, is continued into the lateral sinuses, and extends
  throughout all the sinuses of the dura mater; so that the blood, during
  its passage through the sinuses, does not come in contact with any
  membrane different from that of the veins. 
                The External Jugular.            297

and the great trunks of the neck. They are described in
the account of the brain,  (Vol.  I. p. 308). Into these
sinuses the very numerous veins of the pia  mater open,
proceeding to the sinuses in a  direction the reverse of
that in which the blood flows in those  channels.
   These veins are divided very minutely on the pia mater
before they enter the substance of the brain.
   Into one of these sinuses, denominated the Cavernous,
the ophthalmic vein discharges  its contents.  This vein
proceeds from the anterior part of the  sinus into the orbit
of the eye through the sphenoid fissure.* Its ramifications
correspond generally with those of the  ophthalmic arteryf
and some of them pass  out of the orbit to anastomose
with the branches of the  facial vein.
   The superficial veins of the neck are variously arranged
in different persons. There is often one considerable vein,


           The EXTERNAL JUGULAR,
Which is sent off by the subclavian, very near its union
with the internal jugular; but sometimes it goes off from
that vein much nearer the shoulder. There are sometimes
two external jugulars,  an anterior and a posterior, nearly
of equal size. More frequently  one of them is  much
smaller than the other. In a majority of cases, the princi-
pal externaljugulargoesoff near the junction of the internal
jugular and subclavian, as above stated, and proceeds up-
wards towards the angle of the lower jaw, passing between
the platysma  myoides and the sterno-mastoid muscle. It
often  sends off, at  the basis of  the neck,  one or  more
branches to the contiguous muscles,  and then proceeds
upwards. Near the angle of the jaw,  it often communi-

  • See the account of this fissure in Vol. I, p. 53.
  fThe Vasa Vorticosaof the choroides are one of the exceptions fo
this. See Vol. I. p. 342.
  Vol. II.              2  P 
298  General Account of the Great Vein of the Arm,

cates with the internal jugular: it then continues upwards,
covered with the parotid gland, near the temporal artery,
and finally divides into superficial and deep-seated tem-
poral branches.
  The External Jugular, near the angle of the jaw, often
sends off the facial vein, which crosses  the  basis of the
lower jaw, near the facial artery, and distributes branches
to the  side of the face and to the forehead.  It also very
often sends  off, near this  place, the  internal maxillary
vein, which  generally ramifies in such a manner that its
branches correspond  with those of the internal maxillary
artery. Veins  which correspond to some of the other
branches of the external carotid artery, the lingual, occi-
pital, &c, are often sent off near this place by the external
jugular.  They take the names of the arteries to which
they correspond, and commonly accompany them.


              The SUBCLAVIAN Vein,
Although it originates differently on the two sides of the
neck, is  situated  alike on  each of  them. After parting
with the  internal jugular, it proceeds over the  first rib,
under the clavicle, and does not pass between the scaleni
muscles, as  is the case with the arteries, but  before the
anterior muscle. It soon joins the great artery of the arm,
and  proceeds  before or below  it  to the axilla. In this
situation it gives off branches  to the contiguous parts,
which  correspond with those given off by the artery. In
this Course it also often gives off a large branch, called the


                     cephalic,
Which soon becomes superficial,  and  proceeds down-
wards  between the margins of the deltoid and  pectoral
muscles: it continues superficial  on the  external side of
the  biceps  muscle,  sending off  many subcutaneous 
     General Account of the Great Vein of the Arm. 299

 branches. Near the external condyle of the os humeri, it
 generally sends off a branch towards the middle of the an-
 terior  part of the fore arm, which  is called the Median
 Cephalic, and also some other superficial branches. It then
 continues over the radius, and  inclining  to the back of
 the  fore arm, until it  arrives at the  back of the  hand,
 where it divides into branches, some of which go to the
 thumb.
   In the axilla, the great vein, there called


               The AXILLARY Vein,
 Generally divides into two or three branches. One, which
 is commonly the largest, and appears like the continuation
 of the  main trunk, is called


                The basilic Vein.
 This vessel passes down, deeply seated, to the  bend of
 the elbow. It becomes superficial near the internal condyle,
 and divides into several branches. One of these generally
 proceeds  to join the  median branch of the cephalic, and
 from the union of the two branches is formed  the median
 vein, which passes down near the middle of the anterior
 part of the fore arm. This vein generally sends off a branch
 which proceeds internally, and anastomoses with the deep-
 seated  veins of the fore-arm.
  There are frequently two other branches of the basi-
 lic  vein.  One, which is small, passes down on the  ulnar
side of the anterior part of the fore-arm, but does not ex-
tend to the wrist. The other passes down on the ulna, and
gradually proceeds to the back of the hand, when it  di-
vides into several branches, one of which is generally ap-
propriated to the little finger.
  The AXILLARY veir, after the basilic leaves it,
sometimes divides into two branches, and sometimes con- 
300      Situation of the Inferior Vena Cava.

tinues undivided.  In either case it accompanies the hu-
meral artery, and  takes  the name of HUMERAL Vein
or Veins. It sends off branches which correspond to those
of the artery, and continues to the bend of the elbow:
here it is so divided, that two of its ramifications accom-
pany each of the  three arteries of the fore-arm. These
ramifications sometimes communicate with  each other
by anastomosing branches near the elbow, and they com-
municate also with the superficial veins.

    The superficial  veins of the arm are so different in different
      subjects, that a general description  will rarely apply ac-
      curately to an individual case. It may, however, be ob-
      served, that a Cephalic vein will generally be found, which
      very frequently arises from the subclavian instead of the
      axillary, and commonly continues to the hand on the ra-
      dial side of the arm. The superficial veins,  on the ulnar
      side of the fore-arm, very frequently are branches  of a
      large vein which accompanies the humeral artery to the
      elbow, viz., the basilic; but the median vein, formed by
      .branches of the cephalic and basilic veins, is very often
      not to be found,
                     SECTION II.

   Of the INFERIOR  VENA CAVA, and the Veins
              which are connected with it.
   THIS  great vessel exceeds the  Superior Cava in di-
ameter. It proceeds from the lower part of the right auricle,
and very soon perforates the diaphragm, at a small distance
in front of the spine, and rather to the right of the center.
As the pericardium adheres to the diaphragm at this place,
the vessel appears to  leave it abruptly.  Immediately after
leaving the diaphragm,  it proceeds along a groove in the
posterior edge of the liver, formed by  the great lobe and 
         Situation of the Inferior Vena Cava.      301

the lobulus Spigelii.* After leaving the liver, it continues
downwards, inclining backward and to the left, and is soon
in contact with the aorta,  which is on the left of it. It ac-
companies the aorta  to its great bifurcation, and divides
in the same manner.  It  sends off,  during this course,
branches to the Diaphragm, Liver, Right Renal Gland,
the Kidneys, and the Testicles; and also the Lumbar and
Middle Sacral veins.


              The Inferior Phrenic Veins
Are thus denominated to distinguish them  from other
veins, which are derived from the internal mammary, &c.
They generally accompany the phrenic arteries, and are
distributed in the same manner.


                The HEPATIC Veins
Pass off from the vena  cava, nearly at right angles, into
the substance of the  liver, while it is in the groove of that
viscus, and  before it has  proceeded more  than eight  or
ten lines from the heart.
   They arise from the anterior part of the vena cava, and
are generally three in number.  Sometimes there are two
only, but then one of them divides  immediately after it
enters the substance  of the gland.
   The distribution of these vessels in the liver has  been
detailed in the account of that organ, and, therefore, need
not be stated here; but the veins which unite  to form the
vena portarum, and the trunk of that great vein also, be-
fore it is connected with the liver, may be  regarded as a
portion of the regular venous system, and  ought now to
be considered.
* Sometimes it is completely surrounded by the liver. 
302
Superior Mesenteric Vein.
             The VENA PORTARUM
Passes downwards from the great sinus of the liver behind
the pancreas, and inclining to the left. In this course it
sends branches to the gall bladder, the stomach and pylo-
rus, and the duodenum. At the upper and posterior edge
of the  pancreas, it sends off a very  large branch to the
spleen, which often passes, with slight meanders, along a
groove in the pancreas.


                 The SPLENIC Vein
Often sends off the inferior mesenteric vein, which
proceeds downwards between the aorta and the left por-
tion of the colon. It also sends off some of the coronary
veins and the left gastro epiploic vein to the  stomach;
many small branches to the pancreas; and, finally, either
from the main trunk or its branches before they enter the
spleen, the venae breves, which pass to the great extremity
of the stomach.  Before it enters the spleen, it forms several
ramifications, which  accompany  the branches  of the
splenic artery.
  After sending off the splenic, the Vena Portarum takes
the name of


      The SUPERIOR MESENTERIC Vein;
WThich is larger than the splenic, and passes from behind
the pancreas, before the transverse portion of the duodenum,
into the  mesentery; where it accompanies the superior
mesenteric artery.
  It is evident  that the  above described  portion of the
vena portarum  simply performs the functions of  a great
vein; but when  it takes on the arrangements for entering
the liver, it no longer acts like a vein, but an artery. 
Emulgent Veins.               303
  The lower portion of the  trunk of this vein and its
ramifications  is denominated Vena Porta Ventralis. The
part which ramifies in the liver, Vena Porta Hepatica.


                 The Capsular Veins
Are small vessels,  one on each side. That on the right
passes from the vena cava  to the right glandula renalis.
That  on the left arises from the left emulgent vein.


        The EMULGENT, or RENAL, Veins
Are very large vessels; and, like the arteries, go off nearly
at right angles, one to each kidney.
  The right emulgent vein is not so long as the left, and
it is rather anterior to its corresponding artery. The left
emulgent, in  its course to the kidney, crosses the aorta,
and is anterior to it.
  These veins pass  to  the sinus of each kidney, and
ramify before.they enter it. The ramifications follow those
of the arteries.


                 The Spermatic Veins
Arise one on each side: the right from  the  vena cava,
and the left from the emulgent vein. They proceed down-
wards behind the peritoneum, and on the psoas muscle
generally divide into many branches, which communicate
with each other as they progress downwards, and form
a plexus  denominated  Corpus  Pampiniforme.  These
branches proceed  in  the spermatic cord  to the  back of
the  testis. The principal part enters the body of that gland;
but some of the branches go to the epididymis. In females
the  spermatic vein, like the artery, passes to  the ovary,
the  uterus and its appendages, &c. 
304       Internal Iliac and its Ramifications.


                 The Lumbar Veins
Correspond to the arteries of the same name. They arise
from the posterior and lateral parts of the inferior cava,
and those on the left side pass under the aorta.


               The Middle Sacral Vein
Resembles the artery of the same name in its origin and
distribution.
  The INFERIOR VENA  CAVA  accompanies the
aorta to the  space between the fourth and fifth lumbar
vertebra, and there it also divides into the two


           PRIMITIVE ILIAC VEINS.
The left vein crosses behind the artery  of the right side,
and rather behind the left primitive iliac artery, which it
accompanies until they are  opposite to the junction of the
sacrum and ilium, when it  divides again, like the artery,
into the internal and external iliac veins.


 The INTERNAL ILIAC or HYPOGASTRIC Vein
Descends  into the pelvis behind the artery, which it ac-
companies. Its ramifications correspond in general with
those of the artery, and, therefore, need not be particu-
larly described.


               The ven£ vesicales
Have such  peculiarities  that their ramifications  require
particular attention. They arise from the hypogastric, very
near the origin of the obturator, and are large as well as
numerous.
  They are somewhat different in the two sexes.  In men 
Ramifications of the External Iliac.      305
they form a remarkable plexus on the lateral and inferior
portions of the bladder, and on the vesiculae seminales.
This plexus extends more or less to the prostate: from it
a number of veins proceed to  the  symphysis of the os
pubis, which communicate in their course with the pudic
vein. From thence arises the great vein of the penis, which
proceeds* in the groove  between the corpora cavernosa,
and terminates in the glans penis. This vein often divides,
near the root of the penis, into two: one of which is in the
groove, and the other more superficial.*
   In  females, the  venae vesicales  form  a considerable
plexus on each side of the bladder and vagina. Many veins
pass from these to the upper portions of the bladder and
the  contiguous parts, and form plexuses. The clitoris has
a dorsal vein like the penis, and it originates in a manner
analogous to the dorsal vein of the  male.


           The EXTERNAL ILIAC Vein.
 The great trunk  of the veins of the lower extremity pro-
 ceeds on the inside of the artery, under the crural arch or
 Poupart's ligament. Before it passes from under the arch,
 it sends off two branches which answer to the circumflex
 artery of the ilium and to the epigastric artery.


                 The Circumflex Vein
 Arises from the external side of the iliac vein, and passes
 towards the anterior end of the spine of the ilium. It di-
 vides  into branches which accompany those of the artery
 of the same name.

   * The pudic veins accompany the arteries of that name. They com-
 municate with the plexus, as above mentioned, and continue into the
 penis.
    Vol. II.              2 Q 
306               Veins of the Leg.
                 The Epigastric Vein
Arises from the external  iliac, and accompanies the  epi-
gastric artery.—After passing a small distance inward
and downward, it turns up on the inside of the abdominal
muscles. In the first part of its course it sends off some
small branches to the spermatic cord.
  After passing beyond Poupart's ligament, the name of
the great vessel is changed from external iliac to


                FEMORAL VEIN.
It proceeds downwards at first on the inside of the femo-
ral artery, but gradually changes its relative situation, so
that in the thigh and in the ham it is behind or on the out-
side  of that vessel.
  At a short distance below  Poupart's ligament, after
giving off some small branches to the external organs of
generation, and to the glands of the groin, it sends off on
the internal side of  the thigh a very large vein which is
called the


                  SAPHENA MAJOR.
This vein immediately becomes superficial, and passes
down on the internal side of the thjgh, somewhat ante-
riorly; giving off  some small branches to the contiguous
parts, soon after it originates; and many superficial veins
afterwards. It continues along the inside of the knee and
leg to the internal  ankle, the anterior part of which it
passes over. It then proceeds along the internal part of the
upper surface of the foot to the middle, when  it curves
towards  the external edge, and joins  the lesser saphena.
On the leg and foot  it also sends off many branches, which
anastomose with each other, and with those of the afore-
said  vein. 
    Instances of peculiar arrangement of the Veins.  307

  The femoral vein, after parting with  the saphena,
soon sends off the vena profunda, and the circumflexae
also, when they do not arise from the profunda.  These
veins are generally larger than the arteries to which they
correspond, and their branches are more numerous; but
they observe  the same course.
  The great vein accompanies the artery down the thigh
and through the perforation in the biceps; but it changes
its relative position, so that it is placed  behind or  on the
exterior side of the artery at the lower  part of the thigh.
It is very often behind it in the ham, where, like the artery,
it takes the name of POPLITEAL. In the ham it sends
off another superficial vein, which seems very analogous
to the basilar vein of the arm. This is called


           The Lesser or External Saphena.
It proceeds from the ham over the external head of the
gastroc nemius, and down the outside of the leg, sending
off many branches in its course. It passes behind the ex-
ternal ankle and near the exterior edge  of the upper sur-
face of the foot, about the middle of which it inclines to-
wards the great saphena, and forms with  it the anastomosis
already mentioned.
  The popliteal vein, after passing across the articulation,
ramifies like  the artery, but sends two veins, which ac-
company each of the three arteries of the leg.
  In a few instances some of the larger veins have been
found to be arranged in a manner very different from that
which is commonly observed.
  One case of this kind has already been mentioned in the
account of the liver, * where the Vena Portarum terminated
* See note to p. 135, of this volume. 
308              Pulmonary Vessels.
in the Vena Cava, below the liver, without entering into
it.
  Another very remarkable instance of peculiar arrange-
ment is to be seen in a preparation now in the University
of Pennsylvania, in which  the Inferior  Cava, instead of
opening into the lower  part of the  right auricle, passes
behind it, in the tract of the Vena Azygos, and opens into
the  Superior Cava, in the place where the  Vena Azygos
usually communicates with that vessel, receiving the In-
tercostal Veins in its course.
  In this preparation, the Hepatic Veins communicate
directly with the right auricle, at its lower part; the middle
and left hepatic veins forming one trunk before they enter,
and the right vein  passing in singly.


       Of the PULMONARY Artery and Veins.
  Those portions  of the pulmonary  artery and veins
which are distinct  from the lungs may be described very
briefly.
  It has been already observed,* that the pulmonary
artery arises from the  left and most anterior part of the
basis of the right ventricle, and proceeds thence obliquely
backwards, inclining gradually to the left side for about
eighteen or twenty lines,  when it  divides into  two
branches, which pass to the two lungs. This course places
it under the  curve  of the aorta: for that great vessel passes
over the right branch  of the pulmonary artery, and the
right side of the main trunk of it, in such a manner that
it proceeds  downwards between the  two  branches and
behind the angle formed by their bifurcation. From this
place of bifurcation a short ligament proceeds to the lower
part of the curve of the aorta, which is almost in contact
with it. This ligament was originally the canal that formed
* See page 59 of this volume,. 
Pulmonary Vessels.
309
the communication between the pulmonary artery and the
aorta of the fcetus.* Each of the great branches of the
pulmonary artery takes a direction backwards, and to its
respective side. It soons joins the corresponding branch
of the trachea and the two pulmonary  veins, being ante-
rior to the branch of the trachea, and above the pulmonary
veins. It is also invested, in common with them, by that
portion of the pleura which forms the  mediastinum, and
thuN enters into the composition of the root of the lungs.
   The pulmonary veins are four in number—two on
each side. In conformity to the mode of description which
we have adopted, it may be said that they arise from the
sides of the Left Auricle, and proceed nearly in a trans-
verse direction, two of them to each lung; where they ac-
company the branches of  the artery and of the trachea,
being invested by the mediastinum in common with these
branches. It has been observed, that they differ from veins
in general, by preserving a diameter nearly similar to that
of the arteries which they accompany.
* See page 68. 
SYSTEM OF ANATOMY.

            PART X.
                 OF THE NERVES.

THE nerves are those whitish cords which pass from
the brain and spinal marrow to the various parts of the
body.
  A general account of their origin is contained in  the
description of the basis of the brain and of the spinal
marrow,* which  may be considered as introductory to
the present subject.
   The nerves, in general, appear to be bundles or fasci-
culi of small cords, each of which is composed of a series
of fibres that are still smaller. These fibres consist of me-
dullary matter, which is derived from the brain and spinal
marrow, and is inclosed in a membranous sheath that ap-
pears to arise from the pia mater.  The  smaller the fibre,
the more delicate is the membrane which invests it.
   As the nerves proceed from the brain and spinal mar-
row, through the foramina of the cranium and the spine,
they are inclosed in a sheath formed by the dura mater;
but when they arrive at the exterior extremity of the fo-
ramina in those bones, this coat, derived from the dura
mater, appears to separate into two laminae.  The exterior
lamina combines with the periosteum, and the interior
•See volume I. page S21. 
General Structure of the Nerves.        311
continues to invest  the nerve, but seems to change im-
mediately into cellular substance; so that the exterior coat
of the nerves may be regarded as composed of cellular
membrane, which is continued  from the sheath  derived
from the dura mater.
   It has been supposed that the membrane which forms
the sheaths for the medullary fibrils, of which the nerves
are composed, is of a peculiar nature; but it appears to be
derived from the  pia  mater, investing the brain and the
spinal marrow. It is very vascular.*
   The ramification of a nerve is simply the separation of
some fibres from the general fasciculus. The branch com-
monly forms an acute angle with the main trunk.
   The course of these branches, from their origin to their
termination, is generally as straight as possible.
   When  the nervous cords are examined  in  an animal
recently dead, there  is  an  appearance of white lines ar-
ranged in a transverse  or spiral direction. The cause of
this appearance is not well understood.
   In various parts of the body networks are formed by
the combination  of different nerves,  or the branches of
nerves. In those instances the branches of one nerve unite
with those of another, and. form new branches. These new
branches  again divide, and their ramifications unite with
other new ramifications to form other  new trunks. These
new trunks divide again, and form new combinations in
the same way.
   The trunks last formed proceed to the different parts of

   * Several authors  have written professedly on the structure of the
nerves, viz. Monro, in his " Observations on the Structure and Func-
tions of the Nervous System."—Bichat, " Anatomie Generale."—
Fontana, " Treatise on the Foison of the Viper."—Reil, " Exercita-
tiones Anatomies."—Scarpa, " Annotatipnes Academicae."—Pro-
chaska, " De Structura Nervorum."
   I regret  that it has not been in my power to procure Reil,  Pro-
chaska, or Scarpa. 
312
Plexuses.—Ganglions.
the body, as other  nerves  do which arise immediately
from the brain.
  These combinations are denominated Plexuses. There
are several of them  in the  cavities of the abdomen and
thorax, formed by the ramifications of the par vagum aixl
the sympathetic nerves.  The four lower cervical and the
first dorsal nerve  form a very remarkable plexus of this
kind, which extends from  the side of  the  neck to the
axilla, and  forms the nerves of the arm.  The  lumbar
nerves form a similar plexus,  although not so complex,
from which  the crural nerve arises. The anterior nerves
of the sacrum also  unite for the formation of the  great
sciatic nerve.
  It appears to be clearly  ascertained,  that the  great
object of this peculiar arrangement is the combination of
nervous fibres  from many  different sources,  in  each of
the  nerves, which are distributed to any organ. Thus, the
smaller nerves of  the arm that are distributed  to the dif-
ferent parts, are not to be regarded simply as branches
of any one of the five nerves which are appropriated to
the upper extremity, but as composed of fibres which are
derived from each of them.
  Many of the nerves are enlarged in particular places,
so as to form small circumscribed tumours, which are
denominated Ganglions.
  These Ganglions are generally of a reddish colour. By
very dextrous management, they can be shown to consist
of a texture  of fibres.  The larger cords, which compose
the nerve, seem suddenly to be  resolved into the  small
fibresf of which they  consist.  These small fibres, after
proceeding separately a greater or lesser distance, accord-
ing to the size of the ganglion, and changing their  relative
situation, are again combined in cords which recompose
the nerve.
  These fibres appear to be surrounded by a fine cellular
substance, which  is vascular, moist and soft. It is assert. 
                Structure of Ganglions.             313

 ed that, in fat subjects, an oily substance, resembling fat;
 and  in hydropic subjects, a serous  fluid has been found
 in this texture.
   Ganglions are often  connected with  but one. nerve,
 which seems to enter at one extremity and go  out at the
 other. But they frequently receive additional branches
 from  other nerves, and  send off additional  branches  to
 parts  different from those to which their principal nerves
 are directed.  When  connected  with but one nerve, they
 have been called simple ganglions: when  they receive and
 give off additional branches, they are  denominated com-
 pound ganglions.—It does not appear that there is any im-
 portant difference in their structure in these cases.
   The simple ganglions occur in the nerves of the spinal
 marrow—the posterior  fasciculus of  the nerves having
 always formed a ganglion before it is joined by the ante-
 rior fasciculus. The  sympathetic nerve, throughout its
 whole extent, forms compound ganglions.
   The use of this particular structure does not appear to
 be perfectly known. It seems, however,  certain, that the
 different fibres—(of which the nerves forming ganglions
 are composed)—are blended together and arranged in  a
 manner different  from that in which they were arranged
 before the nerve entered  the ganglion.
   It  ought to be  observed, that the  combination x>f
 nervous fibrillar, so as to bring together those fibrils which
 originally belonged to different cords, seems to have been
 kept in view throughout the whole arrangement of the ner-
 vous system. It is not only in the plexus and the  ganglion
 that this appears, but also  in some of the larger nerves; for
 in them, the fibres which form the cords that compose the
nerve,  instead of running parallel to each  other, along the
whole  extent of the nerve, form a species of plexus in
their course; separating from the fibres with which they
   Vol. II.                2 R 
314             Reproduction of Nerves.

were originally combined, and uniting with the fibres of
other cords; as in other cases of plexus.*
  There have been doubts respecting the possibility of a
reproduction of the substance of the nerves when it has
been destroyed; but it appears to have been clearly proved
by the experiments of Mr. Haighton, that a reproduction
does really take  place.f
  Nine pair of nerves proceed  from the brain through
the foramina of the cranium. They are called Nerves of
the Brain, or Cerebral Nerves. One pair pass off between
the cranium and the spine, which are called Sub  Occipital.
Twenty-nine or thirty pair pass  through the foramina of
the spine: they are denominated Cervical, Dorsal, Lumbar
and Sacral, from the bones with which they are respec-
tively connected. There are seven pair of Cervical nerves,
twelve  Dorsal,  five Lumbar, and five or six Sacral—
amounting, with the nerves of the brain, to thirty-nine or
forty pair.

            NERVES OF THE BRAIN.
   The nerves which go off from  the bram and medulla
 oblongata are named numerically, according to the order
 in  which they occur; beginning with the anterior. They
 also have other names, which generally are expressive of
 the functions of the different parts to which they are dis-
 tributed.
    Those which go to the nose are anterior to all the others,
 and are therefore denominated

    * See Monro's Observations on the Structure and Functions of the
 Nervous System. Plate xviii.
    fSee London Philosophical Transactions, for  1795rPart I. 
Olfactory Nerves.
315
   THE FIRST PAIR, OR THE OLFACTORY NERVES.
They arise by tliree delicate white fibres from the under
and posterior part of the anterior lobes of the brain, being
derived from the Corpora Striata. They proceed forward
to the depression on the cribriform  plate of the ethmoid
bone, on each side of the crista galli. The upper surface
occopies a small sulcus formed  by the convolutions of
the lower surface of the brain, and, therefore, has a lon-
gitudinal ridge on  it.  The  lower surface is flat. Their
texture is like that of the medullary part of the brain.
   On each  side of  the  crista galli  each  of them forms
a pulpy enlargement of a brownish colour, which is called
the bulb, and has been considered  as a ganglion.
   From this bulb many fine and delicate cords go off,
which proceed through the dura mater and the foramina
of the cribriform plate to the Schneiderian membrane.—-
These ramifications  of the olfactory nerve seem to receive
a coat from the dura mater, as they are much  more  firm
after  they  have passed  through  it.  They appear to be
arranged in two rows as they proceed from the ethmoid
bone—one running  near to the septum, and the other to
the opposite surface of the ethmoid bone.*


    THE SECOND PAIR, OR  THE OPTIC  NERVES,
Originate from the  Thalami Nervorum Opticorum, and
appear on the external and lower surface of the brain, on
each side of the sella turcica.
   Each of them seems like a cord of medullary matter,
inclosed in a coat derived from the  pia mater, and has
not the fasciculated  appearance of the other nerves.  The
medullary matter, however, appears to be divided by

                 •See Vol. II. Page 6. 
316        Second and Third Pair of Nerves.
processes  that pass through  it,  which are derived from
the coat of the nerve.
  They proceed obliquely forward  and inward, on each
side of the sella turcica,  in contact  with the brownish
cineritious substance, in which the infundibulum and the
corpora albicantia  of Willis are  situated.* Anterior to
this substance they come in contact with each other, and
again separate, in such a wayr,  that it is  an undecided
question  whether they  decussate each other, or whether
each forms an angle, and  is in contact with the other at
the angle.
  From this place  of contact, each nerve  proceeds to its
respective foramen opticum,  where it receives a coat from
the dura mater, which extends with it to the eye, as has
been described  in theaccount of  that organ.


            THE THIRD PAIR OF  NERVES
Are sometimes called Motores Oculorum, in consequence
of their distribution to  several muscles of the eye. They
arise at the inside of the crura cerebri, and make their ap-
pearance on the basis of the brain, at the anterior part of
the pons Varolii.
  They originate by numerous threads, which soon unite
so as to form a cord that passes  through the dura mater,
on each side of the posterior clinoid process, and continues
through the cavernous sinus, and the foramen lacerum, to
the orbit of the  eye.
  Before  this nerve  enters the orbit it generally divides
into two branches, which are situated one above the other.
The Uppermost Branchis spent principally upon the rectus
superior muscle of the eye, but sends a twig to the levator
palpebrae. The Inferior Branch is distributed to two of the
recti muscles, viz. the  internus and the inferior, and also
* See Vol. I. p. 323. 
            Fourth and Fifth Pair of Nerves.       317

 to the inferior  oblique.  It likewise sends a  twig to a
 small ganglion  in  the orbit, called the  Lenticular  or
 Ophthalmic Ganglion,* from which proceed the fine nerv-
 ous fibres that perforate the sclerotica coat.f


             THE FOURTH PAIR  OF NERVES
 Are called the Pathetic, in consequence of the expression
 of the countenance produced by the action of the muscle
 on which they are spent. They arise from the side of the
 valve of the brain, below and behind the Tubercula Qua-
 drigemina,J and are so small that they appear like sewing
 thread. They proceed round the crura of the cerebrum,
 and appear on the surface between the pons Varolii and
 the middle lobes of the  brain. They proceed  along the
 edge of the tentorium which they perforate, and passing
 through the upper part of the cavernous sinus, enter the
 orbit by the foramina  lacera. They are exclusively appro-
 priated to the Superior Oblique or Trochlearis muscle.


            THE  FIFTH  PAIR OF NERVES
 Are called  Trigemina, because each nerve divides  into
 three great branches.
   These  nerves arise  from  the crura of the cerebellum
 where they unite to  the pons Varolii, by distinct fibres,
 which are connected so as to form a cord or nerve, that is
 larger than any other nerve of the brain. In many subjects
 this cord  seems partially divided into  two portions, the
 anterior of which is  much smaller than the posterior, and
 appears softer at its origin.

  * This ganglion, which is considered as the  smallest in the body,
lies on the outside of the optic nerve, near its entrance into the orbit,
and is generally surrounded by soft adipose matter
  t See Volume I. page 342.
  | Ibid. Page 324. 
318
First Branch of the Fifth Pair.
   It passes into a short canal formed by the dura mater,
near the anterior extremity of the petrous portion of the
temporal bone, at a small distance below the edge of the
tentorium.  It is perfectly loose and free from adhesion to
the surface of this canal; but it soon passes out of it under
the dura mater,  and then adheres to that membrane.
After leaving  the  canal it expands like a fan, but still
consists of fine fibres  which have some firmness.  It is
said that there  are seventy or eighty of these fibres in the
expansion, but they appear to be more numerous. Round
the circumference of the expansion  is a substance  of a
brownish colour, into which the fibres enter. This is the
Semilunar Ganglion, or the Glangion of Gasser, and from
it the three nerves go off.
   These nerves pass  off from  the convex side of the
Ganglion, and are denominated the Ophthalmic, the Su-
perior Maxillary,  aud the Inferior Maxillary.


               The Ophthalmic Nerve
Passes into  the orbit of the eye through  the  foramen
lacerum: it there divides into several branches, which are
called, from their distribution, the Frontal  or Supra-
Orbitar, the Nasal and  the Lachrymal.
   The Frontal or Supra-Orbitar branch proceeds forward
in the upper part of the orbit, exterior to the membrane
which lines it, and divides into two ramifications. One of
these is small,  and passes out of the orbit near the pulley
of the superior oblique, to be spent upon the  orbicularis
muscle and the contiguous parts.
   The other ramification passes through the Supra-Orbi-
tary Foramen,  or through the notch, which is in  the place
of that foramen, and divides into a number of twigs, some
of which pass  transversely towards the  side of the  head,
and communicate with  twigs from the portio dura.  Most
of the others extend upwards on the head. Some are dis- 
Second Branch of the Fifth Pair.        319
tributed to the anterior part of the occipito frontalis mus-
cle, and the integuments of the forehead; others are spent
upon the upper portion of the scalp. Some of the extreme
parts of  these ramifications also communicate  with the
portio dura.
   The Nasal Branch proceeds obliquely forward towards
the inner side of the orbit, and sends a twig in its course
to the lenticular ganglion. It also sends off some small
twigs, to join- the ciliary nerves which go from the gang-
lion. On the  inside of the orbit a branch leaves it, which
proceeds through the Foramen Orbitare Internum Anterius
to the cavity of the cranium, and passes a small distance
upon the cribriform plate of the ethmoid bone, under the
dura  mater,  to a fissure in the said  plate near the crista
galli, through which it proceeds  into the  cavity  of the
nose. Here it divides into twigs, some of which pass on
the septum near  its anterior edge, and terminate on the
integuments at the  end  of  the  nose,  while  others pass
down on the inferior turbinated bone.
   After  parting with the ramification to  the nose, the
remainder  of the nasal branch continues to the  internal
canthus of the eye, and sends twigs to the lachrymal sac,
the caruncula lachrymalis, the eye-lids,  and the exterior
surface of the upper part  of the nose.
   The Lachrymal  Branch  proceeds obliquely  forward
arid outwards, towards the lachrymal gland. In its course
it sends off  a  twig which  passes  through  the  spheno
maxillary fissure, and communicates with a twig of the
upper maxillary nerve, and one or more twigs  that pass to
foramina in the molar bone. The main  branch passes to
the lachrymal gland, and some twigs continue beyond it
to the contiguous parts.


            The Superior Maxillary Nerve.
   The second branch  of the fifth pair is examined with
great difficulty  on account of its peculiar situation. It 
 320       Second Branch of the Fifth Pair: or

 proceeds from the stmilunar ganglion, and passes through
 the  foramen rotundum of the  sphenoid  bone  into the
 upper part of the zygomatic fossa.  In  this situation it
 sends a twig to the orbit by the spheno maxillary fissure,
 and a branch, called the Infra Orbitar, which appears like
 the main nerve, as it preserves a similar direction, to the
 infra orbitar canal. At the same place it sends downwards
 two branches which unite together almost immediately
 after their origin, and, as soon as they have united, enlarge
 into  a ganglion.* This  glangion is  called the Spheno'
 Palatine. It is rather of a  triangular figure, and lies very
 near the spheno-palatine foramen. It gives off a posterior
 branch, which passes through the  pterygoid  foramen to
 the cavity of the cranium: some branches which proceed
 through the spheno-palatine foramen to the nose, and are
 called the Spheno-Palatine or Lateral Nasal Nerves: and
 an inferior  branch, that proceeds  through the posterior
 palatine canal, and is called the Palatine Nerve.
  The small  branch, which was first mentioned, as going
 to the orbit by the spheno maxillary fissure, divides into
 two ramifications. One of them unites with a twig of the
 lachrymal branch above mentioned, and passes out of the
 orbit, through a foramen in the  molar bone, to the face;
 where it is  distributed. The other  passes also through a
 foramen of  the molar bone, into the temporal  fossa,  and,
 after  uniting with twigs  from  the Inferior  Maxillary
 Nerve, proceeds backwards and perforates the aponeurosis
 of the temporal muscle, to terminate  on the integuments
 of the temporal region.
  Before the Infra Orbitar branch enters the canal of that
name,  it sends  off  two twigs,  called  Posterior Dental
Nerves, which pass downwards   on the tuberosity of the
 upper maxillary bone, and enter into small canals in that
bone,  that  are situated behind  the Antrum  Maxillare.

  * Sometimes a single branch passes downwards instead of two; but
it forms a ganglion in the same place. 
Superior Maxillary Nerve.           321
They subdivide into fine twigs that proceed forward to the
alveoli of three or four of the last molar teeth; and pene-
trate each of the roots by a cavity at its extremity. Twigs
also proceed from these nerves to the posterior part of the
gums and the buccinator muscle.
   After the posterior dental nerves have left it, the Infra
Orbitar nerve proceeds forwards in the canal of that name;
and near the extremity of it, gives off the anterior dental
nerve, which  accompanies it for some  distance, and then
proceeds downwards in a canal in  the bone anterior to
the antrum maxillare.  In its course this nerve divides
into many fibres, which pass to the  roots of the incisor,
canine,  and small molar teeth,  each in its proper canal.
These  dental branches sometimes  pass  in  the  antrum
maxillare between  the  lining  membrane  and the bones.
The Infra Orbitar nerve passes  out  of the foramen upon
the cheek, and divides into several branches of considera-
ble size, which are distributed on the face from the side of
the nose to the back of the cheek, and also upon the under
eye-lid and the upper lip.
   The  Pterygoid  Nerve,  or  posterior  branch, passes
backwards, from the ganglion to a canal in the base of the
pterygoid process of the Os Sphenoides, and proceeds
through it.  After leaving this canal, it passes through a
substance almost as firm as cartilage, which closes the an-
terior foramen lacerum, at the basis  of the cranium; and
divides into two branches. The smallest of them, called
the Vidian Nerve,  proceeds with a small artery to the
small foramen, or Hiatus Fallopii, on the  anterior side of
the petrous portion of the temporal  bone, and continues,
through a  small  canal, to join  the  Portio  Dura of the
seventh pair  in the larger canal, called  the Aqueduct of
Fallopius, at the first turn in that canal.* The other branch

   * The late Mr. John Hunter believed that  this nerve parts from
the portio  dura at the lower end of the aqueduct, and  is the corda
tympani.
   Vol. II.               2 S 
322           Superior Maxillary Nerve.
of the pterygoid ner-'e  proceeds to the  Foramen Caro-
ticum, and passes through it, with a twig  of the  sixth
pair, to join the first cervical ganglion of the Intercostal
Nerve.
   The Spheno-Palatine, or lateral Nasal Nerves, consist
of several branches which pass from the spheno-palatine
ganglion, through  the spheno-palatine foramen, into the
nose. Some of them are distributed to  that part of the
pituitary membrane, which is above the upper meatus,
and  others  to  the part which is  immediately below it.
Some of the branches which thus enter the nose are spread
upon tjie septum: one among them extends upon it, down-
wards and forwards, to the anterior part of the palatine
process of the upper maxillary bone, where it enters into
the foramen incisivum,  and terminates in a  papilla in the
roof the mouth.*
   The Palatine Branch proceeds, through the canal form-
ed by the upper maxillary and palate  bones, to the roof
of the mouth and the soft palate. Soon after its origin, it
sends off a twig which proceeds down a small canal  that
is behind it.  It also sends off, as it proceeds downwards,
several twigs to that part of the  membrane of the nose
which covers the inferior  turbinated bone.  When it ar-
rives at the roof of the mouth,  it divides into several
branches which run forwards, and are distributed  to the
membrane which lines the roof of the mouth. Some of its
branches pass to the soft palate, the uvula, and the tonsils;
small filaments pass into the back part of the upper jaw.

   * The curious distribution of this nerve appears to have  been
known to the late John Hunter, and also to Cotunnius; but it is mi-
nutely described by Scarpa, and is delineated by Soemmering in his
plate of the nose—See " Observations on certain parts of the Animal
Economy," by J. Hunter, page 219,—and also Scarpa " De Organo
Olfactus." In this last are some interesting observations relative to
the ducts of Steno. 
Third Branch of the Fifth Pair.         323
 The Inferior Maxillary Nerve, or the Third Branch of
                   the Fifth Pair,
Passes through  the foramen ovale into the zygomatic
fossa, and divides into two branches, one of which sends
ramifications to  many of the contiguous muscles, as the
Temporal, the Masseter, the Buccinator, the Pterygoid;
and also to the anterior part of the ear and the side of the
head. The other branch  passes  between the pterygoid
muscles, and divides into two ramifications, one of which
proceeds to the tongue, and is called the Lingual or Gus-
tatory, while the other passes into the canal of the lower
jaw.
  The Lingual  Nerve proceeds between  the  pterygoid
muscles, and in its course is joined by the chorda tym-
pani. It continues forward between the maxillary gland
and the lining membrane of the mouth; and passes near
the excretory duct of that gland, above the mylo-hyoideus
and the sublingual gland, to the under side of the tongue,
near the point: it then divides into a number of branches
which enter into that body between the genio-hyoideus
and lingualis muscles.—This nerve has been supposed to
be particularly concerned in the function of taste, because
many of its branches continue to the upper surface of the
tongue, especially near the  point.  In  its course it has a
communication with the ninth pair of nerves, and it sends
twigs to the membrane of the mouth and gums, and the
contiguous parts.
  After parting with the lingual nerve, the inferior max-
illary continues to the upper and  posterior orifice of the
canal in the lower jaw. Before it enters this canal it sends
a branch to the sub-maxillary gland, and to the muscles
under the jaw. It then enters the canal,  attended by blood-
vessels, and proceeds  along it  to the  anterior maxillary
foramen, on the side of the chin, through which it passes 
324      Sixth and Seventh Pair of Nerves.
out. In this course it sends twigs to the sockets of the
teeth, and generally supplies all the large and one of the
small grinders. Before it leaves the jaw it sends a branch
forwards, which supplies the remaining teeth on the side
to which it belongs. After passing out, through the. ante-
rior foramen, it is spent upon the muscles and integuments
of the front of the cheek, the chin, and the  under lip.«

            THE  SIXTH PAIR OF NERVES
Are called Motores Externi. They  arise from the com-
mencement of the medulla oblongata, and  proceed for-
ward under the pons Varolii. They  proceed through the
dura mater on the inside of the fifth pair, and appear to
pass through the cavernous  sinuses, but  are inclosed in
sheaths of cellular membrane while  they  are in  those
sinuses. When in this situation they are near the carotid
arteries, and each nerve sends off one or more very fine
twigs, which being joined  by a twig from the  pterygoid
branch of the fifth  pair, accompany  the carotid artery
through the  carotid canal, and then unite themselves to
the upper extremity of the upper cervical ganglion of the
intercostal nerve.
   The sixth pair afterwards pass into the orbit of the eye,
each through the foramen  lacerum of its respective side,
and is spent upon the Rectus Externus or Abductor mus-
cle of the eye.

          THE SEVENTH .PAIR  OF NERVES
Comprises two distinct oor^ds which have  very different
destinations; and have, therefore,  been considered as dif-
ferent nerves, by several anatomists. One of these cords
is appropriated to the interior of the ear, and is  the proper
Auditory Nerve. The other  is principally spent upon the
face, and, therefore, has  been called the  Facial.  They
have, however, more frequently been denominated the
Seventh Pair, and distinguished from each other, in con- 
    Composition of the Seventh Pair.—Portio Dura. 325

sequence  of a great difference  in  their texture,  by the
appellations of Portio Dura and Portio Mollis.
  These two cords  pass off nearly in contact with each
other, from the side of the upper part of the Medulla Ob-
longata, where it is in contact with the pons Varolii; but
the Portio Mollis can be traced to the fourth ventricle,
while the  Portio Dura is seen to arise from the union of
the pons Varolii with the medulla oblongata and the crura
Cerebelli. The  Portia Dura, at its origin, is on the inside
of the Portio  Mollis.—Between these cords are one or
more small fibres, called Portio Media, which seem to
originate very near them, and finally unite with the Portio
Dura.
   Each of the seventh  pair of  nerves, thus composed,
proceeds  from its origin, to the Meatus Auditorius In-
ternus of the temporal bone; and the Portio Mollis divides
into fasciculi, which proceed to the different parts of the
organ of hearing, in the manner described in the account
of the ear.*
   The Portia Dura enters an orifice at the upper and
anterior part of the end or bottom  of the Meatus Audito-
rius Internus.  This orifice is the commencement of a
canal, which has been called the Aqueduct of Fallopius,
and proceeds from the  Meatus Auditorius Internus to the
external foramen,  between the mastoid and stiloid pro-
cesses at the basis of the cranium.  This canal first curves
backwards and outwards, near to the upper  surface of the
petrou.s bone,  then forms  an acute  angle,  and proceeds
(backwards, and downwards)  to the stilo-mastoid fora-
men, passing very near the cavity of the tympanum in its
course.
   The Portio Dura, as it passes into the canal from the
meatus internus, seems to receive an investment from the
dura mater. It fills up the canal, but does not appear to be

                 * See Volume I, page 880. 
 326        Chorda Tympani.—Pes Anserinus.

 compressed. Near  the angle it is joined by the twig of
 the Vidian nerve, which  proceeds from  the pterygoid
 branch of the fifth pair, and enters the 'petrous  bone by the
 small foramen innominatum on its anterior surface. In its
 course through the canal it sends off some very small
 twigs to the muscles  and appurtenances  of the  small
 bones of the ear, and  to  the  ir\astoid cells; and,  when
 it has arrived almost at the end of the canal,  it sends off,
 in a retrograde direction,  a small  branch which proceeds
 into the cavity of the tympanum, (entering it by a foramen
 at the base of the pyramid,) and crosses the upper part of
 it, near  the membrana  tympani,  between  the long pro-
 cesses of the Malleus and  Incus. This twig is the Chorda
 Tympani: it proceeds from the cavity,  by a fissure on the
 outside of the Eustachian tube, to join the lingual branch
 of the fifth pair, as has been already mentioned.*
  The Portio Dura, after passing out of  the  Foramen
 Stylo-Mastdideum, is situated  behind  and within the pa-
 rotid gland. Here it gives small twigs to the back of the
 ear and head, and  to the digastric  and stylo-hyoideus
 muscles. It perforates  the gland  after sending filaments
 to it, and then divides into branches which are arranged
in such a manner that they  constitute what has been called
 the Pes Anserinus.
  To describe the  various branches in this expansion
 would be  more laborious than useful.  Some  of them
 are spread upon the temple and  the  upper  part of the
 side of the head, and unite with the supra-orbitar branches
 of the ophthalmic nerve. Some pass above and below the
 eye, and are distributed to  the  orbicularis muscle, and
 communicate with nervous twigs  that pass through fora-

  * The lateJohn Hunter believed that the chorda tympani is mere-
 ly a continuation of the twig of the pterygoid branch which joins the
 portio  dura above—See Observations on certain parts of the  Ani-
 mal Economy, page 220. 
       Composition oft^e Eighth Pair of Nerves.   327

mina in the malar bone, &c.  Some large branches pass
transversely. They cross the masseter muscle, and divide
into ramifications which are spent upon the cheek and the
side of the nose and lips, and communicate with the small
branches of the superior maxillary nerve.
   A large number of branches pass downwards. Many of
them incline forwards, and are spent on  the soft parts
about  the under jaw; while others proceed below the jaw
to the superficial muscles and integuments of the upper
part of the neck, communicating with the branches of the
contiguous nerves.*


            THE  EIGHTH PAIR OF  NERVES
Are very frequently denominated the  Par  Vagum, on
account of their very extensive distribution.
   They arise from those portions of the medulla oblon-
gata which are denominated the Corpora Olivaria. Each
nerve consists of a cord, which is anterior, and called the
 Glosso-Pharyngeal; and of a considerable number of small
filaments, which  arise  separately,  but  unite and form
another cord,  the  proper Par Vagum.  Associated with
these  is a third cord, called, the Spinal, or Accessory Nerve
 of Willis, which originates in the great canal  of the spine,
 and,  passing up  into the cavity of the cranium, goes out
 of it  with these nerves through the foramen  lacerum.
   The two first mentioned nerves proceed from their
 origin to the posterior foramen lacerum,  and  pass through
 it with the Internal Jugular vein,—being separated from
 the vein by a small process of bone.  They are also separa-

   * A most minute and laborious description of the nerves of the face
 was published by the  celebrated Meckle, in the seventh  volume of
 Memoirs of the Royal Academy of Sciences of Serlin, for the year
 1751,  accompanied with ? plate, exhibiting the side of the head, of
 three times the natural size.  This is republished in the Collection
 Academiquc: Partie Etrangere.—Tom. viii. 
328    Glosso-Pharyngeal Nerve.— Par Vagum.

ted from each other by a small process of the dura mater.
In the foramen they are very close to each  other; but soon
after they have passed through it, thay separate and pro-
ceed towards their different destinations.
  The  Glosso-Pharyngeal proceeds towards the tongue,
between the stylo-pharyngeus and the stylo-glossus mus-
cles, following the course of the last mentioned muscle to
the posterior part of the tongue.  At the commencement
of its course it receives a twig from the Portio Dura and
one also from the Par Vagum. It soon gives off a branch
which passes down  on the inside of the common carotid
to the lower part of the neck, where it joins some twigs
of the intercostal to form the cardiac nerves. AfteltVards
it sends off several twigs to the muscles of the pharynx
and  its internal membrane, and  also  some twigs whieh
unite with others fron»the upper cervical ganglion pf the
Sympathetic, and form a network that lies over the anterior
branches of the external carotid.  The Glosso-Pharyngeal
finally enters the tongue,  at the termination of the hyo-
glossus  muscle; and after sending branches to the lingu-
alis, and the various  muscles inserted into the tongue,
terminates in small ramifications that are spent upon the
sides and middle of the root of the tongue, and upon the
large papilla;.


                  THE PAR VAGUM
Are slightly enlarged after passing through the foramen
lacerum. As they descend, they adhere  to the superior
ganglion of the intercostal, and also to the ninth pair.
They proceed behind  and on the outside of the carotid,
and are contained^ the same sheath of cellular membrane
which  incloses that artery and the internal jugular  vein.
Each of these nerves, soon after it  leaves the cranium,
gives a twig to the glosso-priaryngeal; that soon after
it sends off a branch called the Pharyngeal, which unites 
     Superior Laryngeal Branch of the Par Vagum. 329

to one from the accessory nerve, and  to one or  more
from the glosso-pharyngeal, and proceeds to  the  middle
constrictor of the jjfoarynx, when it expands into ramifica-
tions that form a plexus from which proceed a number of
small twigs that go to the larynx, and some that pass down
on the common carotid artery.
   It then sends off, downward and forward, the Superior
Laryngml nerve, which continues in that direction behind
the carotid artery, and divides into an external and inter-
nal branch.
   The 'Internal Branch, which is  the  largest, proceeds
between the os hyoides and the thyroid  cartilage; and
divides into numerous ramifications which are distributed
to the arytenoid muscles and to the membrane which lines
the larynx and  covers the epiglottis. It is said, that fine
twigs  can be traced into the forarmina, "which are to  be
seen in the cartilage of the epiglottis;—-some ramifications
can be traced to the pharynx;—others communicate with
the branches of the recurrent nerve.
   The External  Branch sends twigs to the  pharynx, to
the lower and inner  part cf the larynx, and to the thyroid
gland.
   In  its course downwards, the great nerve  sometimes
sends off a twig,  which unites with one from the ninth
pair that passes to the sterno-hyoidei and sterno-thyroidei
muscles.
   It uniformly  sends off one  or more twigs, which pass
into the thorax and combine with small branches from
the sympathetic or intercostal nerve, to form the Cardiac
Plexus, which sends nerves to the heart.
   After entering  the thorax, the right  trunk of the Par
Vagum passes before the subclavian artery;  and the  left
trunk before the arch of the aorta* and  immediately after
passing these arteries, eaph of the "nerves divides into an
anterior and posterior branch.—The anterior is the con-
tinuation of the Par Vagum;  the posterior is a nerve of
   Vol. II.               2 T 
 330     Recurrent Branch of the Par Vagum.

 the Larynx; which, form its retrograde course, is called
 the Recurrent Nerve.
   On the left side the Recurrent Nerve winds backwards
 round the aorta, and on the right side round the subclavian
 artery, and proceeds upwards, deeply seated, on the side
 of the trachea, to the   Larynx. Soon  after its origin it
 sends filaments to a ganglion of the sympathetic, to the
 cardiac plexus, and to a pulmonary  plexus soon  to be
 mentioned.  In its course upwards it sends twigs  to the
 trachea and the oesophagus. It proceeds behind the thyroid
 gland, and sends twigs to that organ. At the lower part of
 the larynx it sends of a branch which communicates with
 branches of the superior laryngeal nerve.  It also divides
 into branches which are spread upon the posterior crico-
 arytenoid, and the arytenoid muscles;  and also upon the
 lateral crico-arytenoid  and  the thyro-arytenoid muscles,
 as well as upon the  membrane which lines the back part
 of the larynx and the contiguous surface of the pharynx.
  There is a difference in the arrangement of the recur-
 rents on the different sides, in consequence of one winding
 round the aorta,  while the other winds round the subcla-
 vian artery.
  After sending off the recurrents, each  trunk of the
 Par Vagum  proceeds behind the ramifications of  the
 trachea;  but previously detaches some  small branches,
 which are joined by twigs from the intercostal and from
the recurrent, and form a plexus upon the anterior part of
 the vessels going to the lungs. This Anterior Plexus, after
sending off some minute branches to the cardiac nerves
and  the pericardium, transmits  its branches, with  the
bronchiae and the bloodvessels, into the substance of the
 lungs.
  Some  of the  branches which  proceed  from  the par
 vagum, pass  down  on the posterior part  of the trachea,
 and  enter into the  membrane which  forms it, and the 
          Par Vagum.—Pulmonary Plexuses.      331

mucous glands which are upon it;  and some pass to the
CEsophagus.
   When the parjpgum is behind the great vessels of the
lungs, a number of branches go off transversely, and are
also joined by some fibres from the sympathetic.  These
form  the Posterior Pulmonary Plexus; the ramifications
from  which proceed into the substance of the lungs, and
are principally spent upon the ramifications of the bron-
chia;. It has been said,* that the small twigs, into which
they divide, very  generally penetrate into the small rami-
fications of the bronchiae, and are spent upon their internal
membrane.
   Soon after  sending off the  nerves of the pulmonary
plexus, the Par  Vagum proceed downwards  upon the
oesophagus; the left nerve being situated anteriorly, and
the right posteriorly. Each of these nerves forms a plexus
so as  nearly to surround the oesophagus, as  they descend
on it; but  the network is thickest on the posterior side.
They pass through the diaphragm with  the oesophagus,
and unite again so as to form considerable trunks.
   The Anterior,  which is  the  smallest,  proceeds along
the lesser curvature of the stomach to the pylorus. Some
of its fibres are  spread  upon  the  anterior side of the
stomach and the lesser omentum. Others of them extend
to the left hepatic, and also to the solar plexus.
   The Posterior  trunk sends branches to  surround the
cardiac orifice of the 6tomach. Many branches are spread
upon the under side of the great curvature of the stomach.
Some of them pass in the course of the coronary  artery
to the coeliac, and unite to the hepatic and splenic plexuses;
and one trunk, which  is thiqk although short, proceeds
to the solar plexus.

  • See Buisson, in the continuation of the Descriptive Anatomy of
Bichat. 
332   Different Functions of the Laryngeal, fcfc.


            The Accessory Nerve of Willis,
Which has been mentioned as associated with the eighth
pair of nerves, within  the  cranium, has  a very  peculiar
origin.
   It arises by small filaments, which come off from the
spinal marrow, between the anterior and posterior fasciculi
of the cervical nerves, and proceeds upwards to the great
occipital foramen, between these fasciculi. It commences
sometimes at  the sixth or seventh cervical vertebra, and
sometimes about the fourth. It enters the cavity of the
cranium  through the foramen magnum, and proceeds up-
wards  and outwards, so as to join the eighth pair of nerves^
at some distance from  its origin, and in this course"k re-
ceives filaments from the medulla oblongata.
  After approaching very near to the eighth pair of nerves,
it accompanies it to the foramen lacerum, and passes out
in its own separate sheath. It then leaves the eighth pair
and descends  towards  the  shoulder, proceeding through
the sterno-mastoid muscle. Soon after it emerges from the
cranium, it sends a  ramification to the pharyngeal branch
of the Par Vagum, and another to the Par Vagum itself.
After ^passing through the upper and  back part of the
sterno-mastoid muscle, it  terminates in the trapezius.  It
adheres to the ninth pair of nerves as it passes by it, and
sends a twig to the sub-occipital and some of the cervical
nerves. It also gives ramifications to the sterno-mastoid
muscle as it passes through it.

    It  has already been stated that the Laryngeal and Recur-
      rent Nerves appear to answer different purposes in their
      distribution to the  Larynx.—When both of the recurrent
      nerves are divided in a living animal, the voice seems to
      be lost. When the laryngeal nerves only are divided, the
      strength of the voice remains, but it  is flatter. The re-
      current nerves, therefore, seem essential to the  formation 
Ninth Pair of Nerves.
333
      of the voice. The laryngeal nerves are necessary to its
      modulation.
        The history of the investigation of this subject is con-
          tained in Mr. Haighton's paper in the third volume
          of Memoirs of the Medical Society of London.


            THE NINTH PAIR OF NERVES.
  Each  of these nerves arises from  the  groove in the
medulla oblongata,  between the corpora pyramidalia and
the corpora olivaria. Three or four  fasciculi, of distinct
filaments, unite  to form it. Thus composed, it proceeds
to the anterior condyloid foramen of the occipital bone,
and passes through the dura mater. It seems firmly united,
by the cellular membrane, to the eighth pair, and to the first
ganglion of the sympathetic, soon after it passes from the
occipital bone. It is either connected to the sub-occipital
nerve by a small ramification, or it joins a branch which
proceeds from the sub-occipital to the cervical, and bends
round the transverse process of the atlas. It passes be-
tween the internal carotid artery and the internal jugular
vein, and crosses the  external carotid at the origin of the
occipital artery. At this place it generally sends down-
wards a large branch which is called the Descendens Noni.
Passing forwards, it is  on the outside of the posterior
portion of the digastric  muscle, and  inclines downwards;
but near the tendon of the muscle it turns upwards, and
proceeds on the inside of the mylo-hyoideus, where it di-
vides into ramifications, which, at the anterior edge of the
hyo-glossus muscle, begin to  enter in the substance of
the tongue, between the genio-glossus and the lingualis
muscles.
  Some of the branches of this nerve unite with those of
the lingual branch of the fifth pair. Others are distributed
to almost all the muscles connected  with the tongue.
  The branch called Descendens Noni passes down in the 
  334    Sub-Occipital, or Tenth Pair of Nerves.

  course of the common carotid artery, and sends branches
  in its progress to the upper portions of the coraco-hyoidei
  and sterno-thyroidei muscles; it unites with ramifications
  of various sizes from the first, second and third cervical
  nerves, which form a bow under the sterno-mastoid mus-
  cle, from which ramifications go to the lower portions of
  the sterno-hyoidei and thyroidei  muscles  and of  the
  coraco-hyoidei.


          OF THE CERVICAL NERVES.
   The tenth or last pair of the head, commonly called
 the  Sub occipital, may be arranged with  tfrese nerves,
 because they arise, like them, from the medulla spinalis,
 and are distributed to the nerves on the neck.


             The sub-occipital Nerves
 Arise on each  side of the spinal marrow, nearly opposite
 to the interval between the great foramen of the os occi-
 pitis and the atlas.
  Each of these nerves consists of an anterior and pos-
 terior fasciculus,  or bundle of fibres, which pass  out-
 wards immediately under the vertebral arteries, and form
 a ganglion, from  which proceeds an anterior and a  pos-
 terior branch.
  The anterior branch is united to the second cervical
 nerve below, and  to the ninth nerve, or the hypoglossal,
 above. It  also sends filaments to the  upper ganglion of
 the great sympathetic nerve.
  The posterior  branch is  spent upon  the Recti,  the
 Obliqui, and some other muscles of the head.
  The proper  Cervical Nerves consist of Seven Pair; of
which  the first six go  off between the vertebrae of the
neck, and  the  seventh between the last of the neck and
the first of the back. 
First and Second Cervical Nerves.        335
            The first cervical Nerve
Passes out between the atlas and the Vertebra Dentata.
It originates from two fasciculi, which are connected to
each other at a ganglion, and then separate into an ante-
rior and a posterior branch.*
  The anterior branch is connected by filaments with the
accessory nerve, with the ninth pair of the head, and with
the upper ganglion of the sympathetic. It is also connect-
ed  with the second  cervical  nerve;  and  sends  some
branches to the muscles on the  anterior part of the spine.
  The  posterior branch,  after  communicating  with the
posterior  branches  of the  sub-occipital  and the second
nerves of the neck, perforates the complex us muscle, and
ascending upon the back of the head, is distributed with
the occipital artery.


            THE SECOND CERVICAL NERVE
Sends off, from its Anterior Branch, a  twig which de-
scends to the lower cervical ganglion of the sympathetic,
and a considerable ramification  to the third cervical nerve.
It also sends off some twigs to the sterno-mastoid muscle,
and others to join the accessory nerve. Some  of its small
ramifications pass down upon the external jugular vein,
and others unite with the descending branch of the ninth
pair of the head. A small branch is also concerned in the
formation of the phrenic nerve.  Two larger branches of
this nerve wind round the posterior edge of  the sterno-
mastoid, and are spread under the integuments of the an-
terior, lateral and posterior parts of the neck and  lower
parts of the head;  they  have a communication  with the
portio dura of the seventh pair.y—The posterior branch
  * This arrangement is common to the nerves of the spine. The
ganglion is formed by the posterior  fasciculus.
  t These superficial branches have sometimes  been described as 
 336       Third Cervical, and Phrenic Nerves.

 of this  nerve is spent upon the extensor muscles of the
 head and neck.


            THE THIRD CERVICAL NERVE
 Sends down, from its Anterior Branch, the principal trunk
 of the phrenic nerve. It also sends twigs to the fourth
 cervical, to the lower cervical ganglion of the intercostal,
 and  to the descending  branch of the ninth of the head.
 Some of its branches unite with twigs of the accessory
 nerve, and others are spent upon the muscles and integu-
 ments of the shoulder and lower part of the neck. A small
 Posterior Branch is spent upon the muscles of the back
 of the neck.


         THE NERVES OF THE DIAPHRAGM
 Are  generally denominated  the  Phrenic.  The  principal
 root of each of them is commonly  derived from the third
 cervical  nerve, but frequently the second and the fourth
 cervical  nerves contribute to their formation; and they
 are sometimes joined by a  twig which is derived from
 the ninth pair.
  Each nerve proceeds down the neck, between the rectus
 capitis major and the scalenus anticus, and continues along
 the fore part of the scalenus anticus; it descends into the
 thorax within the anterior end of  the  first rib, between
the subclavian vein and the artery. It sometimes receives
a twig from the fifth cervical nerve, and a twig passes be-
tween it and  the great sympathetic.  After entering the
thorax, they descend, attached to the mediastinum, before
the root of the lungs. In consequence of the projection of
the point of the heart  to the left, the course of the left is
a little different from  that of the right; that of the right

coming from a plexus; but they often arise directly from the Second
Cervical nerve. 
     Remaining Cervical Nerves.—Brachial Plexus. 337

proceeding in a more perpendicular direction. Whf-nthey
arrive at the diaphragm, they divide  into many ramifica-
tions,  which have a radiated arrangement, and terminate
on the fibres of that muscle, both  on the upper and lower
surface.  Some fibres  from  each nerve are  continued
downward, and communicate in the abdomen with fibres
from the intercostal.


THE FOURTH, FIFTH, SIXTH, AND SEVENTH CERVICAL
                       NERVES,
May be comprised in one description. They pass off suc-
cessively  from the Medulla Spinalis, between the ver-
tebra;, like the other nerves.  Their Posterior Branches
are generally distributed to the back of the  neck, and are
very small. Their  Anterior Branches are principally ap-
propriated to the upper extremities, and are large. They
generally  send  each a  small  twig to  the lower cervical
ganglion of the intercostal nerve, and a few small branches
to some of the contiguous muscles.  They are arranged
and combined so as to  form the network, now to  be de-
scribed, which is called the Brachial or Axillary Plexus;
and, in the formation of this plexus, they are joined  by
the first dorsal nerve.

            The BRACHIAL PLEXUS
Extends from the lower part of the side of the  neck, into
the arm-pit. It commences in the following manner. The
fourth  and fifth cervical nerves proceed downwards, and,
after uniting to each other  about an inch and a half below
their egress from the spine, they  separate  again, almost
immediately, into two branches.
  The sixth cervical nerve, after passing downwards, di-
vides also into  two branches, one of which unites with
  Vol. II.               2U 
338      Construction of the Brachial Plexus.

the uppermost branch that proceeds from the union of the
fourth and  fifth, and the other with the lowermost, and
they all proceed downwards.
  The seventh cervical is joined by the first dorsal, which
proceeds upwards, and unites with it at a short distance
from the spine. The cord produced  by their junction soon
unites with one of the cords above described. As these
different cords proceed downwards, they divide, and their
branches again  unite.  The axillary artery, which  passes
in the  same direction, is  surrounded  by them.  In this
manner the axillary plexus is often formed.
  The muscles about the shoulder, both before and be-
hind, are supplied by the axillary plexus. Thus, it sends
branches to the Subscapularis, Teres Major, and Latissi-
mus Dorsi, behind; and to the Pectoralis Major and Minor,
and the Mamma, before. It also sends off a branch called
the Scapularis,  which commonly arises from the upper
part  of the plexus, and proceeds through the notch in the
upper costa of the scapula, to the supra and infra spinatus,
teres minor, &.c.


                  Nerves of the Arm.
   All  the  great nerves of the arm are derived from the
axillary plexus. There are six of them, which are denomi-
nated The Musculo Cutanetis; The Median;* The Cubital,
or Ulnar; The Internal Cutaneus;  The Radial or Muscu-
lar Spiral; and the Circumfiex or  Articular.
   The MUSCULO CUTANEUS, Or PERFORATING NERVE,
passes obliquely  through  the upper part of the coraco
brachialis muscle. Before it enters the muscle, it sends
a branch to it.  After leaving the muscle, it passes down
the arm between the biceps and the brachialis internus, to
which it also gives branches. It proceeds to the  outside
* Sometimes called Radial. 
        Musculo Cutaneus and Median Nerves.      339

of the biceps, and continues under the median cephalic
vein to the anterior  and external part of the fore arm;
along which it passes,  under the integuments. On the
lower part of the fore arm it divides into many branches,
which extend to the root of the thumb and the back of
the hand, and terminate in the integuments.
   The  median  nerve, which is one of the largest of
the arm, often proceeds from the axillary plexus next to
the musculo cutaneus; it passes down the arm, very near
the humeral artery, within the edge of the biceps flexor
muscle, and, during ihis course, gives off no branches of
any importance. After passing the bend of the elbow,  it
proceeds, under the  aponeurosis of  the biceps,  between
the brachialis internus  and  the pronator teres, and con-
tinues down near the middle of the fore arm, between the
flexor sublimis and the flexor profundus. At the elbow it
sends branches to several muscles on the anterior  side of
the  fore arm,  and to  the integuments.  Among these
branches is one,  called the  Interosseal  Nerve,  which
passes down on the anterior  surface of the interosseal
ligament, with the artery of that name. This nerve sends
branches, in its course,  to the long flexor of the thumb
and the deep flexor of the fingers. When  it arrives at the
pronator quadratus, it sends branches to that muscle, and,
passing between it and  the interosseous ligament, per-
forates the ligament, and  soon terminates on the posterior
side of  the wrist and hand.
  As the median nerve proceeds downwards, it be-
comes more superficial; and continuing among the ten-
dons of the flexors of the fingers, it gives off a branch
which is principally spent upon the integuments of the
palm of the  hand. This  great nerve  passes with the ten-
dons under the annular ligament; and immediately after,
while it is covered by the Aponeurosis Palmaris, and by
that portion  of the artery which is called Arcus Sublimis,
it divides into branches, which separate from each other 
340            Cubital or Ulnar Nerve.
at acute angles, and subdivide so as to send a ramification
to each side of the thumb, of the index, and of the middle
finger; and to the radial side of the ring finger.
  The cubital or ulnar nerve is also of conside-
rable size. It passes down on the inside of the triceps ex-
tensor muscle, to the great groove formed  by the olecra-
non process and the internal  condyle of the os humeri;
and in this course it often sends a branch  to the triceps,
and some smaller twigs to the upper part of the fore arm.
From the groove it proceeds on the anterior part of the
fore arm, between  the flexor carpi ulnaris  and the flexor
sublimis, to the wrist. At a small distance above the wrist
it sends off a branch, called the Dorsalis, which passes be-
tween the flexor ulnaris and the ulna, to the back of the fore
arm and wrist,  where, after sending ramifications to the
integuments and contiguous parts, it divides into branch-
es which pass to the little finger and the finger next to it.
Those branches send  off, in  their course, many twigs
which pass to the skin and cellular substance.
  The ulnar nerve then  proceeds with the artery, over
the annular ligament, on the  radial side of the os pisiforme,
and divides into two branches; one of which is superficial,
and the other deep-seated.
  The Superficial divides into two principal branches, an
external and an internal. The external passes under the
aponeurosis palmaris; and, after sending a branch to com-
bine with one from the median, and some twigs to the
contiguous muscles, it subdivides into two branches, one
of which goes to the ulnar side of the ring  finger and the
opposite side of the little finger. The other branch sends
off  some twigs to the muscles, and proceeds along the
ulnar  side of the little finger.
  The  Deep-seated palmar branch of the ulnar nerve,
passes between the muscles of the little finger, under the
tendons of  the  flexors, and accompanies the deep-seated
arterial arch in the palm of the hand, giving branches to
the interossei, and other contiguous muscles. 
           Radial, or Muscular Spiral Nerve.      341

   The radial  or  muscular spiral nerve is one of
 the largest nerves of the arm. It passes from the axillary
 plexus downward, backward and outward, under the tri-
 ceps  muscle, to the external side of the os humeri.  In
 this course it gives  off several branches to the different
 portions of the triceps. It also frequently gives off a large
 branch, which passes downwards on the outside of the
 olecranon, to the back of the fore arm,  and continues to
 the back of  the hand, furnishing  many branches which
 terminate in the integuments. It then proceeds downwards •
 between the  supinator radii  longus and the  brachialis in-
 ternus. Immediately after passing the articulation of the
 elbow,  it divides  into two branches denominated the Su-
 perficial and  the Profound. The Superficial soon joins the
 radial artery, and proceeds downwards, sending branches
 to the contiguous muscles. In its course about the middle
 of the arm, it crosses the tendon of the supinator longus,
 and proceeds between it and the tendon of the extensor
 carpi  radialis longior;  it soon  after divides into  two
 branches, which are  principally distributed to the thumb
 and forefinger, and also to the integuments.
   The  Profoundbranch proceeds to the  back of the  fore
 arm under the radial  extensor, and continues to the back
 of the wrist and hand. Into this course it divides into two
 branches, which are distributed to the contiguous muscles
 and tendons,  and  the integuments.
  The internal cutaneus nerve is the smallest of the
 nerves which  proceed from  the axillary plexus. It de-
 scends in the course  of the basiiic vein, and very near it.
 Above  the elbow it divides into an Internal Branch,
 which proceeds over  the Basilic Vein,  and separates into
 branches that pass down on the side of  the fore arm;
and an  External Branch that passes under the Median
 Basilic  Vein,  and continues  down on the anterior  part
of the fore arm.
  The  articular  or  circumflex nerve  proceeds 
342
The Dorsal Nerves.
 backwards from the plexus, between the teres major and
 minor, and passes nearly round the body of the os humeri,
 at a small distance below its head. It is distributed to the
 contiguous muscles and to the articulation; but its  princi-
 pal branches  terminate in the deltoid muscle.


             THE DORSAL NERVES
 Proceed from the cavity of the spine between the  dorsal
'vertebra;.  They are  sometimes  called  Intercostals,  be-
 cause they pass between the ribs, like the bloodvessels of
 that name. There are twelve pair of them, and they  are
 named numerically, beginning from above.
   These nerves proceed from the medulla spinalis by two
 fasciculi of fibres—one from each of its lateral portions,
 —the posterior fasciculus is  the largest.  After passing
 through the lateral foramen and the dura mater, a ganglion
 is formed by the posterior fasciculus: the  anterior fascicu-
 lus unites to this ganglion  at its external extremity; and
 one nerve  is formed, which  almost immediately divides
 into an  anterior and a posterior branch, of which the  an-
 terior is  the largest.
   The posterior branch proceeds backwards,  and  is dis-
 tributed to the muscles of the back.  The anterior  branch
 passes towards the angle of the rib, in contact with  the
 pleura.  Soon after its  origin, this anterior branch sends
 off two  ramifications which unite to the intercostal nerve,
 at the ganglion; it then proceeds forwards with the blood-
 vessels, between the internal and external intercostal mus-
 cles, in  the groove near the  lower  margin of  the ribs;
 and terminates on the anterior part of the thorax. In its
 course it sends branches, not only to the  intercostal mus-
 cles and pleura, but to the  other muscles and the integu-
 ments of the  thorax.
   Some of the dorsal nerves differ from  the others, as to
 the ramifications which they send off. 
        General Account of the Lumbar Nerves.    343

  The First Nerve, of this order, joins the lower cervical
nerves in the axillary plexus; but it sends off the ramifi-
cations to the sympathetic; and also a branch, which passes
under the first rib, like the other dorsal  nerves.
   The  Second Nerve, sends off a branch, which passes
through the  external intercostal muscle into the axilla,
and combines there with  a branch of the cutaneous nerve,
being distributed  to the internal and  posterior part of the
arm.
   The  third dorsal nerve also sends off a branch, which
is distributed to the axilla and the back part of the arm.
   These branches of the second  and third dorsal nerves,
are called intercosto-humeral nerves.
   The lower dorsal nerves supply the muscles and integu-
ments of the abdomen.


              Of the LUMBAR Nerves.
   There are five  pair of these nerves.  The first of them
passes off between the first and second of the lumbar ver-
tebra;, and the others succeed regularly; so that the last
pair is situated between  the last lumbar  vertebra and the
sacrum.
   The first lumbar nerves arise from the  medulla spinalis,
before it forms the cauda equina;  the other  four pair are
formed by the cauda  equina.
   They commence  by  anterior  and posterior  fasciculi,
which are united at  a  ganglion.  From  this ganglion,
anterior and posterior branches  go off, which  are  very
different in size,  the anterior being the largest.
   The posterior  branches are distributed to the muscles
of the back.  The anterior send branches to the ganglions
of the  sympathetic  nerve, and also communicate  with
each other to form the Lumbar Plexus,  which is situated
on the lateral parts of the bodies of the Lumbar Vertebra;, 
344      Lumbar Nerves.—Lumbar Plexus.

before their transverse processes, and supplies nerves  to
the muscles of the thigh.


            THE FIRST LUMBAR NERVE
Is connected, by its anterior branch, to the last dorsal and
the second lumbar.  From the same branch,  ramifications
go off to the Quadratus Lumborum, and obliquely across
that muscle,  to the lower part of the abdominal muscles
near the spine of the ileum.


            THE  SECOND LUMBAR NERVE
Sends off a muscular branch downwards and outwards:  it
also sends off the small branch, called the External Sper-
matic, which passes down in such a direction, that it per-
forates the transversalis and the obliquus internus muscles,
near their lower margin, at a  small distance from the
superior anterior spine  of the  ileum, and then proceeds
within  the lower edge  of the  tendon  of the external
oblique to the abdominal ring, through  which it passes.
In the  male it is distributed to the spermatic cord and
scrotum,  and in the female, to  the labia pudendi.  In the
female it also sends a branch to the uterus.*  The Second
Lumbar, after  sending off these branches, passes  down-
wards,  and  joins  the  Third lumbar  nerve. From this
union of the second and third nerves, a branch called the
Cutaneus Medius, which will be soon described, proceeds
downwards.
   After sending off this branch, the  united trunk of the
second and  third joins the Fourth; and from this union
are sent off the   Obturator Nerve,  which passes through
the aperture in  the membrane  that closes the foramen
thyroideum;  the  Crural Nerve, which passes under Pou-

  * The external  spermatic often comes off from the first lumbar
nerve. 
            Obturator Nerve.— Crural Nerve.        345

  part's ligament;  and a  third branch that proceeds  down-
  wards, and joins the Fifth lumbar nerve. The Fifth lum-
  bar nerve, with this accession from above, descends into
  the pelvis, and unites with the sacral nerves.
     This arrangement of the lumbar nerves  constitutes the
  Lumbar Plexus,  which, has been  already  stated, fur-
  nishes three nerves to  the lo ver extremity, viz. tiie Cu-
  taneus Medius, the Obturator, and the Crural Nerve.
     The Cutaneus Medius which arises from the union of
^"',thc second and third nerves, as has been already observed,
  proceeds downwards, and frequently adheres to the crural
  nerve, for a short distance,  near  Poupart's ligament, but
  soon leaves it, and  descends on  the  inside of the thigh,
  supplying the integuments as low as the knee.


                 THE  OBTURATOR  NERVE
   Descends into the pelvis, and passes out of it at the upper
   part of the foramen thyroideum;  proceeding  downwards
   in an internal direction,  to be distributed  on the inside of
   the  thigh.
     This nerve is generally  accompanied by the obturator
   artery and vein; the  artery  being above, and  the vein
   below it. When  it has arrived  at  the foramen  ovale or
   thyroideum,  it sends off a  branch to the  internal and ex-
   ternal obturator muscles, and, after passing these muscles,
   divides  into two  branches  which are distributed to the
  muscles on  the inside  of the thighs,  the adductors, the
   pectineus, the gracilis, &c.


                   THE CRURAL NERVE
   Is situated at first behind, and then on the outside of the
   psoas muscle.  It passes under Poupart's ligament with
   the great femoral vessels,  being on the outside of the
   artery.
     Vol. II.               2 X 
 346         Crural Nerve.—Sacral Nerves.

   It is distributed to the integuments,  and also to the
 muscles, which are situated on the  anterior and internal
 parts of the thigh. Some of  its  ramifications go off before
 it  passes under Poupart's ligament.  Several of  them are
 spent upon the integuments, and are therefore denomina-
 ted Cutaneous.—They  are  distinguished  by the  terms
 Cutaneus Anterior,  Cutaneus Internus, &.c, according to
 their situations.
   The deep-seated  branches are the  largest. They are
 principally spent upon the  muscles  on the anterior and
 the internal side of the thigh, viz. the four extensors, the
 adductors, the pectineus, the  sartorius,  and the gracilis.
 Among these nerves  there is one, called  the  Saphenus,
 which has a different destination. It accompanies  the great
 artery of the thigh  to the place  where  it perforates the
 Adductors: it there  separates from the artery,  and passes
 over  the  tendon of  the Adductors,  under the  sartorius
 muscle; thence it continues,  with the great saphena vein,
 on  the  inside  of  the leg,  to the internal ankle;  sending
 branches to the integuments  in its course. It terminates in
 skin and cellular substance on the  upper and internal sur-
 face of the foot.


                The SACRAL Nerves
 Are composed of those cords of the cauda equina, which
 remain after the formation of the lumbar nerves. They are
 frequently  stated to  consist  of five or six pair, four of
 which pass through  the foramina  of the sacrum, and the
fifth between  the sacrum and  the os coccygis.* The cords
of which they are respectively composed arise by anterior
and posterior fasciculi. When they  have arrived opposite
to the foramina of the sacrum, through  which  they are to
pass, a ganglion is formed, at which they unite,  and then

  • The  sixth pair,  when they exist, proceed in a groove in the os
 roccygis. 
            Sciatic Plexus.—Pudic Nerve.         347

divide into anterior and posterior branches.*  The upper-
most of the  anterior branches are large, and pass through
the anterior  foramina of the  sacrum.  The posterior are
small,  and go through the posterior foramina.
   The Posterior Branches are generally spent upon the
muscles which lie on the  sacrum, and posterior parts of
the pelvis, externally.
   The anterior branches of the three first nerves send ra-
mifications to the sympathetic. They unite to each other,
and are joined by the last lumbar nerve,  and  by a branch
of the fourth sacral,  in  the formation  of the great sciatic
nerve. This union constitutes the sciatic plexus.
   The anterior  branch of  the  fourth  nerve  transmits
branches  to the sympathetic: it  also sometimes sends a
branch to the united nerves above, or the sciatic plexus.
It sends branches to the hypogastric plexus, and to the
contiguous muscles.
   The fifth  and sixth pairs, which are very small, termi-
nate also  in the contiguous  muscles and in the integu-
ments.
   From the sciatic plexus, or the nerves which com-
pose it, several smaller  branches go off.  There are gene-
rally two which pass off backwards through  the ischiatic
notch, and  are denominated  Gluteal,  as they are distri-
buted  to the glutei muscles. From the lowermost of these
a branch descends on the thigh.
   The Pudic Nerve, which is appropriated to the organs
of generation, also passes off from this plexus, and ap-
pears to consist of fibres which are derived from each of
the nerves that compose it. It proceeds between the sacro-
sciatic ligaments, and divides into two  branches—an in-
ferior  and a superior.  The  inferior passes between the
erector penis and the accelerator urinse. muscles, and is

  •The ganglions of the fourth and fifth nerves are extremely small
and not so near the foramina as those of the others. 
 348       Course of the Great Sciatic Nerve,

 distributed to those  muscles,  to  the^ulb of the urethra
 and the interior of that canal, to the scrotum and dartos.
   The superior proceeds along the os pubis to  the sym-
 physis, and passes between the bone and the body of the
 penis to  the dorsum. A considerable branch accompanies
 the artery on the  dorsum, and terminates, by many rami-
 fications,  on the glans penis; after sending branches in its
 course to the integuments generally, and to the prepuce.
   In females,  the Inferior Pudic  Nerve  proceeds along
 the external labia pudendi  to  the  mons veneris, sending
 off many ramifications in its course.
   The Superior Pudic Nerve proceeds, as in males, along
the branch of the pubis to the superior surface  of the
 clitoris, and terminates principally upon the extremity of
 that organ.
   The sacral  nerves unite  in the sciatic  plexus to form
 the great nerve of the lower extremity, which is next to
 be described.


           The GREAT  SCIATIC Nerve
 Proceeds from the pelvis through the  ischiatic notch,  be-
 tween  the pyramidalis and the  superior gemellus muscle:
 it then passes down to the back part of the thigh, between   -
 the tuberosity of  the ischium and the  great trochanter of
 the os femoris and continues  downwards, inclining from
 within outwards,  to the ham, where it is situated between
 the tendons of the semi-tendinosus and semi membranosus
on the internal side, and the tendon of the biceps  on the
external.  In this course it sends off branches to  the mus-
cles on the posterior part of the thigh.
   As the great nerve passes down the thigh, it sends off
obliquely, downwards and outwards, a large branch which
is called the Fibular, that passes across  the head  of the
fibula to  the external and anterior  part of the leg. The
place where  this  branch separates from  the  main nerve 
Distribution of the Fibular Nerve.       349
is different in different  subjects. It continues in contact
with  it for  some  distance, connected only by cellular
membrane.


         THE FIBULAR OR PERONEAL NERVE
Proceeds downwards on the inside  of the tendon of the
biceps, and crosses obliquely to the outside of the external
head of the gastroc nemius: it then passes inwards between
the  long  peroneus  muscle  and the fibula; and  descend-
ing between the muscles on the front of the leg, divides
into two  branches, one of  which inclines to the exterior
bide of the leg, and the other preserves an internal situa-
tion. In its course from  the great sciatic nerve to the
fibula, it sends off some superficial ramifications.  The two
branches  into  which it divides, after passing  over the
fibula, continue downwards. The Internal, after supplying
the muscles on the anterior part of the leg,  passes under
the annular ligament like the anterior tibial artery; and on
the upper part of the foot, divides into two ramifications,
one of which proceeds forwards near the internal edge of
the  foot, and  the other near  the  external;  they divide
again, and are distributed to the parts on the upper surface
of the foot, one of their ramuli descending with the con-
tinuation of the anterior  tibial artery to  the sole of the
foot.
   The External Branch of the fibular nerve,  as it pro-
ceeds downwards, supplies ramifications to the contiguous
muscles, and, passing through  the fascia on the outside of
the  leg,  continues between it  and the skin towards the
foot.  In this course it generally divides into two branches
which are spent upon the upper surface of the foot.
   The GREAT  SCIATIC  Nerve, after the fibular
nerve leaves it, continues down the thigh,  between the
tendons of  the flexors, behind the great bloodvessels, and
of course exterior to them. 
350       Distribution of the Tibial Nerve.

   In the ham, this great nerve takes the name of POPLI-
TEAL, and proceeds across the articulation of the knee,
between the heads  of the gastroc nemii, to the posterior
side of  the tibia: here it passes through the upper portion
of the soleus  or gastroc nemius internus,  and  continues
between it and the long flexor of the toes, near the Pos-
rior Tibial Artery;  descending with  that artery  to  the
hollow of the os calcis. In this situation it has the name of


             POSTERIOR  TIBIAL NERVE.
   At the commencement of this course, a small distance
below the internal condyle of the os femoris, it sends off a
branch of considerable size called the Communicans Tibia,
or  Saphena  Externa,  which  passes  down behind  the
gastroc  nemii, and gradually inclines externally, so that
it is situated on the external edge of the  tendo Achillis,
soon after the commencement  of that tendon,  and pro-
ceeds behind the external ankle, near the outer side of the
foot, to  the smaller toes; distributing branches to the con-
tiguous  parts. In its course on the back of the leg, it sends
off a branch which unites with one of the superficial rami-
fications of the fibular nerve, and descends to  the outer
part of the foot.
   The tibial Nerve, in  its course downwards,  sends
branches to the contiguous muscles; and a few twigs which
form a species of network on the artery. In the hollow of
the os calcis it sends off a superficial branch to the integu-
ments of the sole of the foot, which proceeds on the out-
side of the aponeurosis plantaris: it there also divides into
branches, which are denominated the Internal and Exter-
nal Plantar Nerves.
   The Internal Plantar Nerve proceeds forwards, along
side of  the tendon of the long flexor muscle of  the great
toe, giving off small  branches  in its course. About the
middle  of the foot it divides into  four branches,  one of 
       Commencement of the Sympathetic Nerve.    351

which proceeds to the inside of the great toe; and a second
to the angle formed by the great toe and the toe next to it,
where it divides  and sends a branch to the  opposite sides
of those toes: the other two branches are distributed in a
similar manner,  to  the  succeeding toes.  These  digital
brandies arc connected with each other by small ramifica-
tions.
   The External Plantar Nerve proceeds with the external
plantar artery towards the  external side of the foot,  be-
tween the short flexor of the toes and the flexor accessorius.
Near the external edge  of the foot,  about the  posterior
end of the metacarpal bones, it divides into three branches.
One proceeds to  the outside of the little toe; another passes
to the angle between the fourth toe and the little toe, and
divides into  branches which are distributed to the  cor-
responding sides of these toes. The  third branch proceeds
more deeply in  the  foot, from the  external towards  the
internal edge  of it, and is spent upon the deep-seated
contiguous muscles.


THE GREAT SYMPATHETIC OR  INTERCOSTAL NERVE
Commences in the cranium with those small ramifications
of the pterygoid branch of the upper maxillary nerve, and
of the sixth pair,  which accompany the  carotid artery
through the canal in the  petrous  portion of the temporal
bone.  These  small  nerves form a  network which  sur-
rounds  the artery  in  the^canal, and gives rise  to  the
incipient  sympathetic, a small cord  which passes down
close to  the nerves of the eighth  and ninth pair of the
neck. Opposite to the second cervical vertebra, this nerve
is swelled or dilated, so as to form a body of a light red
colour, which is more than an inch  in length, and has the
form of  two  cones  united to each other at their bases.
This is the Superior  Cervical Ganglion of the Sympathetic
Nerve,  and from it the nerve  descends, behind the  Par 
 352       First Ganglion, and other Cervical

 Vagum,  on the front part  of the neck. This ganglion re-
 ceives twigs from the first, second, third and fourth pairs
 of cervical nerves, and also from the  eighth and ninth
 nerves of the head. It sends off several twigs, which pass
 behind the  carbtid artery, at its bifurcation, an:! are joined
 by twigs of the Portio Dura and the Glosso-Pharyngeal
 nerves. From these united  twigs  proceed very small ra-
 mifications, which accompany several branches of the  ex-
 ternal  carotid artery,  and some of them pass down with
 the Common  Carotid.
   This superior ganglion also furnishes small twigs which
 accompany the  Glosso- Pharyngeal to the tongue and pha-
 rynx.  Sometimes a twig from it passes  on the  back part
 of the thyroid  gland to communicate with the recurrent
 nerve. From this ganglion go off some small branches,
 which, uniting with others from  the superior laryngeal
 nerves, form the  superior  or superficial cardiac  nerve,
 which will be soon described.
   The trunk of the Sympathetic Nerve descends, on the
 front of the neck, from  this ganglion, as has been already
 stated. In its  course it receives  very small twigs from
 the fourth and fifth  cervical nerves, and sends some very
 small twigs which  appear to go to the oesophagus, and
 some which unite to the  laryngeal nerve and  go  to  the
thyroid gland.  Some twigs, which are larger, proceed
from it into the thorax, and go to the cardiac plexus here-
 after to be described.
  Opposite to  the  interval  between  the  fifth  and  sixth
cervical vertebra; it forms  another ganglion, of an irregu-
lar shape, much smaller than the first.  This ganglion, in
different  subjects,  differs  in size  as well as  in several
other respects.  Sometimes it is  entirely wanting,  and
sometimes  it is  doubled.  It is  denominated the Middle
 CerOical, or Thyroid Ganglion.—When the fourth, fifth,
 and sixth cervical nerves do not send ramifications to  the 
       Ganglions and Branches of the Sympathetic.   353

 sympathetic nerve  above,  this ganglion  receives tvvies
 from them.                                         &
   The Middle Cervical, or Thyroid Ganglion, sends many
 ramifications downwards. Some of them enter the thorax
 and contribute to  the formation of the Cardiac Plexus;
 others accompany the inferior  thyroid  artery^ and,  with
 twigs from the recurrent nerve, form a plexus which  ex-
 tends  towards the  thyroid gland.  Some proceed  down-
 wards before, and  others behind,  the  subclavian artery,
 to the next ganglion;  and among them is generally  one
 which may be regarded as the trunk of the Sympathetic.
   This third Ganglion is denominated the Inferior  Cervi-
 cal, or the First Thoracic.  It is almost constantly found
 m the same situation, viz. between the transverse process
 of the last cervical vertebra and the head of the  first rib
 and is partly covered by the  origin of the vertebral artery.
 It is generally larger than the middle ganglion. It receives
 branches from the sixth and  seventh cervical,  and the two
 first dorsal nerves. Ramifications  pass  from it to the par
 vagum and recurrent nerve, and also to the  cardiac and
 pulmonary plexus.
  From  this ganglion  the  Sympathetic Nerve proceeds
downwards on the  side of the spine, as will be described
hereafter.
               The Nerves of the Heart,
 Being derived  from branches which have already been
 mentioned, are now to be described.
   They arise  principally from an  arrangement of nerves
 denominated the  Cardiac Plexus, or Plexuses, which id
 situated about the curve of the aorta, and extends, on the
 posterior side  of it, from the root of the arteria innomi-
 nata to the bifurcation  of  the  pulmonary  artery. This
plexus is composed of nerves which are principally form-
ed by the union  of small ramifications that are  derived
  Vol. II.              2 Y 
354         Branches of the Sympathetic.
from the three above mentioned ganglions of the  Sympa-
thetic Nerve, and the nerve itself; and also from the Par
Vagum and some of its branches.
  These nerves are denominated the Cardiac. They de-
scend on their respective sides of the neck, but are some-
what different on the different sides. On the right side three
nerves have  been described as  particularly entitled to this
name, and on the lejt side but two.
  The first on the right side is denominated Superior or
Superficial Cardiac Nerve. It generally  arises by several
fine threads, which unite into one delicate cord that passes
down by the side of the common carotid. When it has
arrived on  a line with the middle  ganglion, it sends  a
twig to the thyroid plexus, and another that communicates
with a twig from the par vagum, which continues down-
wards on  the carotid  artery. After  passing  beyond the
ganglion, it  divides into  several branches, which unite
themselves to branches of the recurrent nerve that are
going to the middle ganglion.
  The second, which is denominated the Middle Cardiac,
the Great Cardiac, or the Deep Cardiac, is the largest  of
the three. It arises from the Middle Cervical or Thyroid
Ganglion, by five  or six fine fibrils, which  finally form
one, that passes  before and across the subclavian; and at
that place, as well as lower down, it receives twigs from
the par vagum:  below this, it is joined by a considerable
twig  from  the  recurrent, and terminates in the Cardiac
Plexus, to which it contributes largely.
   The third cardiac nerve of the right  side  is called the
Inferior or  the Small Cardiac Nerve. It originates from
the third, or lower cervical ganglion, by many fibrils which
unite into a smaller number that form a plexus. It crosses
behind the subclavian, and proceeds  on the outside of the
Arteria Innominata to the curve of the aorta; continuing
between it and the  pulmonary  artery,  to the anterior co- 
Branches of the Sympathetic.         355
ronary plexus. In this course  it  receives several  fibres
from the recurrent and the par vagum.
  On the left side the first cardiac nerve arises  from the
upper ganglion. The second derives its origin  from the
two lower ganglions.
  The left superior or superficial cardiac nerve arises like
the right,  by many distinct fibres,  and proceeds down-
wards in the  same way.  It descends between the carotid
and the subclavian, and  when it has arrived at  the place
where  they originate  from the aorta,  it divides into  a
great number of small ramifications. Some pass before
the aorta, either to join the branches of the inferior cardiac,
or to unite with the cardiac branches of the left nerve of
the par vagum. The others proceed behind the aorta, and
enter into the common cardiac plexus.
  The second cardiac nerve of the left side may be  called
the Great Left Cardiac,  and has a double origin as  above
mentioned. The principal branch in its composition arises
from the lowest cervical  ganglion, and passes behind the
transverse  portion of the subclavian artery. Where the
inferior thyroid  arises from the  subclavian, this branch
receives  a considerable  number of ramifications,  which
arise from  the upper ganglion,  and are  interwoven with
each other before they unite  to it*  It passes behind the
curve  of the  aorta, and  terminates  in  the great cardiac
plexus, which it particularly contributes to form. Here it
is joined by many fibres  from the par vagum.


                 The Cardiac Plexus
Is situated principally  behind the curve of the aorta, at a
small distance above the heart.  It commences as high as
the origin of the Arteria Innominata, and extends down-
wards to the bifurcation of the pulmonary artery.
  As hat been already mentioned, it is  principally com-
posed of branches from  the middle  cardiac nerve  of the 
 356   Plexus formed by the Nerves of the Heart.

 ri£ht side, and the inferior cardiac nerve of the left; but it
 receives branches from  the superior  cardiac of the left,
 and sometimes of the right  side.  Some  fibres of the
 inferior cardiac of the right are also united to it.
   Many branches proceed from this plexus.
   A small number pass upon the aorta, and  seem to enter
 into its texture.*
   Some of them also combine with  the ramifications of
 the Par  Vagum in the anterior pulmonary plexus.
   The majority proceed to the basis of the heart,  near
 the  origin of the pulmonary artery and  the aorta, and
 constitute the proper nerves of that organ. They accom-
 pany the coronary arteries,  and are so  arranged around
 them that, by some anatomists, they have  been said  to
 form plexuses, which have been denominated Coronary.
   The sympathetic nerve, as has been  stated above,
 proceeds from  the ganglion,  called the Lower  Cervical,
 or the First Thoracic, before the neck of the first  rib.  It
 continues to descend, in the same direction, along the
 spine, exterior  to the pleura, to the inferior part of the
 thorax. Near the head of each rib it forms a ganglion,
 which unites with the intercostal nerve behind it, by ,two
 branches, and thus forms  an indirect communication  with
 the medulla spinalis.
   From several of the  uppermost of these ganglions, small
 twigs  proceed to the  pulmonary plexus, and also to the
 great trunk of the aorta, below the curve, forming a spe-
 cies of network, or plexus, upon it.
   From  the  ganglions near  the  heads of  the  fifth and
 sixth ribs, and  from  four or five  of the ganglions which
 succeed them, small nerves arise, w Inch  proceed  down-
 wards  on the sides of the bodies of the vertebrae, and unite
 into one trunk that is denominated  the Splanchnic Nerve,
 because it is distributed to the viscera of the abdomen.—
 This nerve proceeds behind the crus of the diaphragm, on

  * It has heen asserted,  that some of the anatomists of Paris have
traced these nerves on the aorta, to a great distance from the heart. 
     Sympathetic Nerve, and its Splanchic Branches. 357

 its respective side, into the abdomen. A second and smaller
 nerve,  of the same destination, called the Lesser Splanch-
 nic Nerve,  arises  lower down, from two or three of the
 lowermost  dorsal  ganglions,  and  penetrates  separately
 into the cavity of  the abdomen: it then generally divides
 into  two branches, one of  which unites to the  great
 splanchnic  nerve,  and  the other proceeds to the  renal
 plexus, soon to be described.
   As soon as the great splanchnic  nerve has entered the
 abdomen, it divides into many branches, which commonly
 form small ganglions on each side of the cceliac, but above
 it. These ganglions are generally contiguous; but some-
 times they are at a small distance from each  other, and
 united by nerves. They are, however, commonly spoken of
 as one, and called the semilunar ganglion. They are
 of irregular forms,   and  very different  from each other in
 size, as well as form.  Those formed by  the splanchnic
 nerve on one side are sometimes different from those on
 the other.
   From this assemblage of ganglions proceed many small
 nerves, which are woven together so as to form a network
 denominated the solar plexus.
   T.his plexus is  situated  anterior to the spine and the
 crura of the diaphragm; behind the stomach, and above
 the pancreas; and is extended upon the coeliac and superior
 mesenteric  arteries. Some ramifications from the par va-
 gum and the phrenic also join it.
   The  lower part of the solar plexus, which surrounds
 more immediately the coeliac artery, is termed the  Cceliac
 Plexus. From it networks of nerves extend upon the great
 branches of the artery to the organs which they go to.
   They  extend  to the stomach  (although it is  supplied
 by the par vagum) along the superior  coronary or gastric
 branch of the hepatic; and the fibres in their composition
being spread upon  the coats of the stomach,  unite  with 
358       Arrangement of the Nerves of the

the branches of the par vagum, which  are also  spread
upon them.
   A similar network, denominated  the Hepatic Plexus,
extends upon the Hepatic Artery, and from it to the Vena
Portarum; and accompanies  those  vessels into the sub-
stance of  the liver. It also sends branches to the  biliary
duct  and gall  bladder; to the stomach by the arteria gas-
trica  dextra; and to the omentum.
   The Splenic Artery is invested by a similar but smaller
arrangement of nerves, denominated the Splenic Plexus.
In its course to the spleen, this plexus sends some  nerves
to the pancreas;  and also to the stomach  and omentum,
with the left gastric artery.
   The  superior mesenteric  artery  is surrounded by a
network,  which extends to  it  directly from  the sojar
plexus, and is the largest of all which proceed  from that
plexus.  The Mesenteric Plexus at first nearly surrounds
the artery, and proceeds with it  between the laminae of
the mesentery. In this  course it sends branches, with  the
arteria colica dextra, to the transverse portion of the colon.
Between the lamina; of the mesentery, it  sends ramifica-
tions with all the branches  of the artery,  to the small in-
testines  generally; to the  coecum, and the right portion of
the colon; as well as to the mesenteric glands.
   From  the lower part of the solar  plexus  a network
proceeds, on the front of the aorta, to the  inferior mesen-
teric artery, and  surrounds it.  Nerves from this  plexus
accompany the artery to the left portion of the colon and
the rectum. Some  of their ramifications combine with
those of the hypogastric plexus.
   The Emulgent Artery is  attended  by nerves,  which
are arranged like a network on its anterior and posterior
surfaces, and are  denominated the Renal Plexus. They
are derived from the solar plexus, and frequently contain
small ganglions.  They  proceed  with  the artery  to  the 
Abdominal Viscera.
359
fissure of the kidney, and are distributed with its different
ramifications, in the substance of the organ.
   Some branches pass from them to  the renal gland with
 the capsular artery.
   Before the renal  plexus arrives at the kidney, it  sends
off, from its inferior part, some few fibres, which, after
joining some others from  one  of the lumbar nerves,  ac-
company the spermatic arteries, and are, therefore,  called
the Spermatic Plexus.  In the male,  these fibres proceed
through the abdominal ring, and many of them go  to the
testis, but  they  are  followed  with great  difficulty,  on
account of their small size.
   In the female, they go to the ovary and the fallopian tube.
   From the great  plexuses above, a  small network con-
tinues downwards  on the  aorta, receiving fibres from the
intercostals  on each side;  at the great bifurcation  of the
 aorta it divides, and is joined on each  side by many rami-
 fications from the third  dorsal  nerves, which thus form a
 plexus of considerable  extent, that  sends nerves to the
 bladder, rectum, and vesiculae seminales in males; and to
 the uterus and  vagina, as well  as the bladder and rectum,
 in females.* This is called the  Hypogastric Plexus.
   The plexuses above  mentioned are  derived  from  the
 splanchnic nerve, which came  off from the Sympathetic
 in the thorax.
   The sympathetic nerve, after giving off the lesser
 splanchnic, is diminished  in size,  and approaches nearer
 to the bodies of the vertebrae.  It passes through  the crura
 of the diaphragm,  and then proceeds forwards and down-
 wards upon the spine,  between the  tendinous  crura of
 the diaphragm and psoas  muscle;  near the vena cava on
 the right side, and  the aorta on the left. In  this course, it

   * Although the testicle receives nerves which are derived from the
 Sympathetic, the penis and other external parts of the organs of ge-
 neration do not: the nerves which accompany the pudic artery being
 derived from those which unite to form the great Sciatic. 
360     Termination of the Sympathetic Nerve.

generally receives one or two small cords from the anterior
branch of each of the lumbar nerves: these cords proceed
downwards and forwards, between the bodies of the ver-
tebra; and the psoas muscle,  and a ganglion is generally
formed at the place where they join the nerve.
  In its descent on the lumbar vertebrae, the Sympathetic
sends off several nerves that unite to the network which
descends on  the aorta from the plexus  above.  After
passing over  the lumbar  vertebrae,  it descends into the
pelvis, close to the sacrum,  on the inner side of the great
foramina: here it also forms ganglions, and communicates
with the sacral nerves, and likewise with the hypogastric
plexus. It terminates on the os coccygis, where its minute
fibres join those of the opposite side. 
SYSTEM  OF ANATOMY.

            PART XI.
           Ot THE ABSORBENT  VESSELS.

 PHE absorbent vessels are small transparent tubes, of a
 delicate structure, which exist in considerable numbers in
 almost every part of the body.
   These  tubes  originate upon the surfaces  of all the
 cavities of the body; and of the cellular membrane, in all
 the various parts into which it penetrates; upon the inter-
 nal surface of the stomach and the intestines; and probably
 upon the skin.
   Those which  originate in the Lower Extremities  and
 the Cavity of the Abdomen, unite and form a large trunk
 called the thoracic duct, which  proceeds through the
 thorax,  and terminates in the left Subclavian Vein, at its
junction with the Internal Jugular. Those  of the Left
 Upper Extremity, the Left Side of the Head, and the con-
 tiguous parts, form a trunk which terminates in the same
place. While the remaining absorbents, or those of the
Right Upper Extremity, and the Right Side of the Head,
fcfc. also form a trunk, which terminates in the correspond-
ing part of the Right Subclavian Vein.
  The absorbent vessels of the middle size, which arise
from the union  of the small vessels,  and  unite  to form
the  larger;  in their  progress to these large vessels, pass
  Vol. IT.              2 Z 
562       Structure of the Absorbent Vessels.
 through  certain bodies which have  been  denominated
 Conglobate Glands, and may be considered as appendages
 of the absorbent system.
   The absorbent vessels are composed of two coats, which
 are thin, but dense and firm, and also elastic. The coals of
 the thoracic duct may be separated from each  other. The
 internal surface of the exterior coat is fibrous. The inter-
 nal coat is a delicate  but  strong  membrane.—There is
 great reason  to  believe that the above mentioned  fibres
 are muscular, or at least irritable: for the absorbent ves-
 sels have been observed, by Haller,  to  contract upon the
 application of strong sulphuric acid.  They have also been
 observed to propel their contents with  considerable rapi-
 dity, by their own contraction, independent of pressure, or
 of motion communicated by any other body.
  Bloodvessels are sometimes observable in the coats of
 the larger absorbents, in injected subjects.  The vascularity
 of these tubes may also be inferred from the inflammation
 which frequently takes place in them.
  Nerves have not been traced into their texture; but the
 absorbents seem  to  be painful when they are inflamed,
 and, therefore,  it is probable  that  they are supplied with
 nerves.
  The absorbent vessels are very generally supplied with
 valves, which are much more numerous in some of them
 than in  others;  and are different in their number, in the
 same vessels,  in different subjects.
  Very frequently there are several  valves in  the course
 of an inch: sometimes a valve will not appear in  the
 course of several inches. In the Thoracic Duct, the num-
 ber of valves is very different in different subjects. These
 valves are folds or plaits of the internal membrane, and
are  of a semi-circular form. There are commonly two of
them  together,  originating  from  opposite  sides of  the
vessel.
  The absorbents are generally somewhat dilated on  the 
Commencement of the Absorbents.        363
side of the valve which* is next to their termination, and
this occasions  their knotted  appearance  when  they are
injected. The object of this valvular structure seems to be
the prevention of retrograde motion of the  contained fluid,
in wnsequence of lateral pressure.
   Where the different trunks of the absorbents open into
the veins, there are one or two valves to  prevent the re-
gurgitation of the blood into them.
   The  valves  of course  prevent the injection  of the
branches  of these vessels from  their  trunks.—In some
animals the valves have  sometimes  been  ruptured, or
forced back; and the absorbents have been injected in a
retrograde direction.  There are but two or three  instances
upon record where this has been practicable in the Human
Subject.
  In consequence of the impracticability of injecting the
small brandies  from  the  larger, the absorbent  vessels
cannot, generally, be  demonstrated  at  their commence-
ment,  or origin. It  is, however, to  be  observed, that
the lacteals, or Absorbents of the Intestines, appear
no way  different from other  absorbents; and  they have
been  seen distended  with chyle, from  their commence-
ment, in  certain subjects who had died suddenly. Their
origins  have been described very differently by different
observers.
   Mr. Cruikshank describes them as originating on the
surfaces  of the villi, by a number of very small radiated
branches with open orifices;  which branches soon unite
to form a trunk.
   Lieberkuhn believed them to commence in the form of
an ampullula.—See page  105 of this volume.
   The second  Monro also believes that the absorbents
begin by very small tubes, with open orifices,  in several
species offish.*

 * See his work on the Structure and Physiology of Fishes, p. 34. 
364               Conglobate Glands.
  It is stated by Dr.  Soemmering, upon the authority of
Haase, a German anatomist, that when mercury is forced
backwards in the absorbent vessels of the foot  and the
heart,  it has sometimes escaped on the surfaces of those
parts.  The probable inference from  these  facts is,  that
those vessels originate  by open  orifices  on the  surfaces
of the heart and foot.
   The bodies connected with the absorbent vessels, which
are called Conglobate Glands, are generally of a roundish,
or  irregular oval form,  and  somewhat flattened. They
are of various sizes, from two lines in diameter to more
than twelve. Their colour is frequently whitish, but some-
times it is slightly inclined to red. They are invested  with
a covering of cellular membrane, which appears like a
membranous coat;  and they are connected to the contigu-
ous parts by a loose cellular substance. When the absorb-
ent vessels connected with these bodies  approach near to
them, they divide into a number of ramifications, most
 of which enter  into  the substance of  the gland,  while
 some of them run  over it.  On the opposite side of the
 gland a  number of branches go  out,  which unite  and
 form trunks similar to  those which  entered  the gland.
 The vessels which  enter the  gland are  called Vasa Infe-
 rentia, and those which go out of it Vasa efferentia.
    These vessels are generally  much  convoluted in the
  substance  of the glands, so that those bodies sometimes
  appear  like  a mere convolution  of absorbent vessels.
  There  has been much diversity of sentiment respecting
  the structure of these organs.*
    The absorbent  vessels,  in the different parts of the

    * Mr. Abernethy states, that the mesenteric gland of the Whale
  consists of large spherical bags, into which a number of the lacteals
  open. Numerous bloodvessels are  ramified on the surfaces of these
  cysts; and injection passes from them into the cyst. He also found
  cells in the glands of the absorbent vessels, in the groin and the
  axilla of the hor«e—See Philosophical Transactions, for 1796, Part I. 
         Fluid Contained in the Absorbents.         365

body, generally contain fluids resembling those which are
found  in  those parts.  Mr.  Hewson  opened  the large
absorbents in many living animals of different kinds, and
found  that they contained a  transparent fluid, which co-
agulated when exposed to the air.
   The arrangement of these  vessels resembles that of the
veins  in several respects. Many of them are superficial;
but there are also deep-seated absorbents^which accom-
pany the bloodvessels. 
366
                    CHAPTER I.

  OF THE ABSORBENTS OF THE LOWER EXTREMITIES, THE
              ABDOMEN, AND THE THORAX.


UNDER this head are arranged the ramifications of  all
the vessels which unite to form the Thoracic Duct.


                     SECTION I.

      Of the Absorbents of the Lower Extremities.

   These'absorbents,  like the veins, are superficial and
deep-seated. The Superficial lie in the cellular membrane,
very near the skin; and form an irregular network which
extends over the whole limb. They are, however, most
numerous on the internal side.
   The Deep-seated accompany the arteries like the veins,
and there are two at least to each artery.

              The Superficial Absorbents
Have been injected from the toes so as to form a network,
which occupies the upper surface of the foot. They have
also been injected in  a similar manner on the sole. Those
on the  upper  surface of the  foot  generally proceed  up-
ward on the anterior and inner side  of the  leg;  but some
of them pass on the external side of it.  Those on the sole
are continued on the back of the  leg, but communicate
very frequently with the anterior  vessels. Some of the
absorbents from the  outside of the foot and leg enter into
 some of the popliteal glands, soon to be described; but they 
        Absorbents of the Lower Extremity.       367

are not numerous; and the principal.number continues up
to the glands of the groin. The absorbents which originate
on the surface of the thigh, as well as  those which pass
over  it from below, incline gradually along the  anterior
and posterior surface, to the internal side of it; on which
they proceed,  in  great  numbers, and  very near to each
other, to the inguinal glands.  Superficial absorbents pro-
ceed  also from the  buttock and lower  part of the back,
from  the lower part of the abdomen, the perineum, and
the exterior of the genital organs, to these glands.


              The Deep-seated Absorbents
Are named from the arteries they accompany.


            The Anterior Tibial Absorbents.
   The anterior tibial artery is  generally attended by one
which comes with it from the sole,  and  by  another which
commences on the upper  surface  of the foot. The first
mentioned absorbent continues  with the artery. The last,
often  passes  through an aperture in the interosseal  liga-
ment,  about  one  third  of the distance  from the ankle to
the knee, and accompanies the fibular artery, while the an-
terior tibial artery is joined by other absorbents about the
same  place. In some instances a small absorbent gland oc-
curs in this course, at a short distance below the knee.

            The Posterior Tibial Absorbents
Have  been injected from the under side  of the toes.  They
accompany the ramifications on the sole of the foot; and
after uniting,  continue  with the main trunk up  the leg,
where  they enter into the popliteal glands.
  The Peroneal Absorbents arise also from the sole of the
foot, and its external side. They accompany the peroneal 
368     Absorbents of the Lower Extremity.

artery, and terminate in the  popliteal  glands, which re-
ceive also the absorbents from the knee and ham.
   From these glands four or five absorbent vessels proceed,
which accompany the great bloodvessels of the lower ex-
tremity; and, proceeding with them  through the aperture
in the tendon  of the adductors, continue upwards until
they enter some of the glands of the groin.
   The glands of the ham and groin, which are so inti-
mately connected with the absorbents of the lower extre-
mity, are very different from each other.
   The Popliteal  Glands,  or  those  of the Ham, are but
three or  four  in number, and very small in size.  They
are generally deep-seated, and very near the artery.
   The Inguinal Glands vary in number,  from  eight to
twelve or more. They are superficial  and deep-seated.
The superficial communicate principally with the superfi-
cial absorbents. The lowermost of them are at  some dis-
tance  below Poupart's  ligament, and the uppermost are
rather above  it.  They are exterior  to the  fascia of the
thigh. Their number is generally six or  eight,  while that
of the deep-seated is but three or four.
   The superficial absorbents  from below, approach very
near to  each other,  and enter these glands.  They are
commonly  distributed among three  or four of the lower-
most; but some of them pass by these, and proceed to
one that is  higher up; and sometimes there are  absorbent
vessels which pass to the abdomen without  entering into
any of the glands of the groin.
   The deep-seated absorbents pass  into the deep-seated
glands, which, as has been already observed, are but few,
and lie very near the artery under the fascia of the thigh.
The two sets of glands  are  connected to each other by
many absorbent  vessels  that pass  between them.  The
vessels which  finally  go  out of these  glands are con-
siderably less  in number than those which enter into
them. They proceed under Poupart's ligament, and, in 
         Inguinal and External lliae Glands.      369

some instances,  a large proportion  of them pass through
three glands which lie  below this ligament, and are often
so arranged, that they lie on each side of the great femoral
vessels, and above them. One very frequently is found on
the inside of the femoral .vein, in the vacuity between it
and the internal  part of the ligament.  All the absorbents
of the  lower extremity,  however, do  not  enter  these
glands. Some pass along with the great vessels and enter
other glands near the  margin of the pelvis.  Some also
descend a short distance into  the pelvis, and unite with
vessels that are passing from the pelvis to the plexus and
the glands that surround the external iliac.
   The  absorbents  which proceed  from the glands last
mentioned, joined to those  which pass under Poupart's
ligament, without entering these glands;  and some which
come from the pelvis;  form a large plexus, which almost
surrounds the external iliac vessels, and contains  many
glands.
   These External Iliac Glands vary in  their number from
six to ten or twelve.  They lie on the side of the pelvis, in
the course of the external iliac vessels, and some of them
are of considerable size. These  glands  and the plexus of
absorbents, extend  in the track of the iliac vessels, to the
first lumbar vertebra.  In  this  course they are joined by '
the plexus which comes from  the  pelvis; and soon after
they arrive at the Lumbar Glands, which form a very large
assemblage, that extends from the bifurcation of the aorta
to the crura of the diaphragm.
   These glands lie  irregularly,  on the aorta and the vena
cava, and  the lumbar vertebrae.  Most  if not all the  ab-
sorbents above  mentioned pass  through some of  them;
and from the union  of these absorbents, some of the great
branches,  which unite to form the thoracic duct,  are
derived.
   In  this  course from the  thigh to the lumbar glands,
these absorbent vessels are joined by several others. The
  Vol. II.               3 A 
370         Absorbents of the Testicles, &te.
Superficial Absorbents of  the  scrotum  commonly enter
into the upper inguinal glands, and thus unite to the great
body of absorbents.
  The Absorbents of the Testicles originate in the body,
and the coats  of  the  testicle, and in the epididymis; and
are remarkably large and numerous.  They proceed along
the spermatic cord,  through the abdominal  ring, to the
lumbar glands.  These vessels are remarkable for the little
communication they have with each other.
  The Deep  seated Absorbents  of the  Scrotum accompa-
ny  the  absorbents of, the  testicle to the lumbar glands;
but those  which are superficial  enter the upper inguinal
glands.
  The Absorbents of the Penis are also deep-seated and
superficial. The deep-seated arise from the body of the
penis,  and accompany the  internal pudic artery into the
pelvis.  The superficial absorbents arise from the prepuce,
and pass along  the dorsum of the penis. There are fre-
quency several  trunks which receive branches  from the
lower surface of the penis in their course. At the root of
the penis they generally separate to the right and left, and
pass to the glands on the respective sides.
  In females, the absorbents of the interior of the clitoris
accompany the  internal  pudic artery. Some,  which arise
about the  vagina,  pass through  the  abdominal  ring with
the round ligament; and others proceed  to  the inguinal
glands. 
        Absorbents of the Pelvis and the Kidneys.    371


                      SECTION II.

     Of the Absorbents of the Abdomen and Thorax.
   The Absorbents of the lower portions of the parietes of
the Abdomen and the Pelvis unite into trunks that follow
the epigastric, and the circumflex  iliac, as well as the lum-
bar and sacral arteries, &c. They proceed to some of the
glands  which are in the  groin; or  in  the  external iliac,
the hypogastric, or some of the contiguous plexuses.
   The Absorbents of the Womb are extremely numerous;
and, in the gravid state, are very  large. Those which are
on the neck and anterior part of the uterus, join the hypo-
gastric  plexus. Those which are on the posterior part of
the body, accompany the spermatic vessels.
   The Absorbents of the bladder pass to small glands on
its lateral and inferior  parts, and  finally join the hypo-
gastric plexus.
   The Absorbents of the Rectum are of considerable size.
They pass through glands that lie upon that intestine,  and
unite with the lumbar plexus.
   The Absorbents of the Kidney are superficial and deep-
seated.  They are very numerous, but, in a healthy state
of the parts, are  discovered  with difficulty. Cruikshank
describes  them as they appeared, filled with blood,  in con-
sequence  of pressing  upon  the  kidney when  its veins
were full of blood. Mascagni did  not inject the superficial
vessels with mercury; but describes them as they appear-
ed when filled with colourless size, after he had injected
the bloodvessels of the organ with the coloured fluid.—
The deep-seated  absorbents pass out of the fissure of the
kidney with the bloodvessels, and unite with the  superfi-
cial;  they proceed to the lumbar plexus,  and pass into
different glands.
  Absorbent vessels can  be  proved to proceed  from the 
372    Lacteals, or Absorbents of the Intestines.

pelvis of the kidney, and the ureters, by artifices analogous
to those above mentioned.
   The Glandula Renales are also supplied with absorbents,
which  are  numerous  in  proportion  to  the  size  of the
organs. They commonly join those of the kidney.


           The Absorbents of the Intestines
Have generally been called LACTEALS, from the white
colour of the chyle which they contain: but there seems
no reason  for believing that  they are different in their
structure and nature from the  absorbents in other parts of
the body.  A  small number  of them appear  as  if  they
formed a part of the structure of  the  intestines, and ori-
ginated  from their external surface, as they do in other
parts of the abdomen;  while  the  principal part of them
are appropriated to the absorption of the contents of the
cavity of the intestines.
  The first mentioned  absorbents run between the mus-
cular and peritoneal coats, and proceed for so me distance
lengthways on  the intestine,   while the  others proceed
for  some distance within the  muscular coat, with the ar-
teries;  and after  passing  through it, continue between
the lamina?  of the mesentery.
  Branches of  these different absorbents are frequently
united  in  one  trunk;  so as  to  prove  that  there  is no
essential difference between them.
  The absorbents  which come from the internal surface of
the intestines commence in the villi.  The manner in which
they originate has  been the subject  of considerable in-
quiry, as has been stated in the account of the intestines.*
  The lacteals  or absorbents of  the  intestines  are very
numerous.  They pass  between the laminae of the mesen-
tery, to glands which are also seated between those laminae.
* See page 105. 
        Lacteals, or Absorbents of the Intestines.    373

The number of these glands is very considerable,* and
they are various in  size—some being very minute, and
others eight or ten lines in diameter. They are generally
placed at  a small distance from each other, and are most
numerous in that part  of the mesentery which is nearest
to the spine. They are  almost always at some distance
from the intestines. They appear to be precisely like the
absorbent glands, in other places.
   These absorbent vessels, in their course frequently divide
into branches;  which sometimes go to the same gland,
sometimes to different glands,  and sometimes unite with
other absorbent vessels. As they proceed, they frequently
enlarge  in size.  When they have arrived near the spine,
they frequently  form three or four trunks, and sometimes
one or  two;  which proceed in  the course of the superior
mesenteric artery, until they have arrived near to the aorta.
Here they either pass  into the thoracic duct, or descend
and join the trunks from the inferior  extremities, to form
the thoracic duct. The absorbents of the great intestines are
not equal, in  size to those of the small; but they  are nu-
merous. They  enter into glands, which,are very near, and
in some places, in contact with  the intestine; and are com-
monly  very small  in size. The vessels which arise  from
the  caecum, and the right portion, as well as the arch of
the colon, unite with those of  the  small intestines; while
the vessels from the left side of the colon, and the rectum,
proceed to the lumbar glands.
   The  absorbents of the intestines are frequently injected
with mercury;  but the injection does not proceed to their
termination with so much facility as it does in other  ves-
sels of  the  same kind.  They  have,  however,  very often
been seen in animals, who were killed for the purpose after
eating milk; and in several human subjects who died sud-
denly during digestion.—The  description of the origin of
* They have been estimated between 130 and 150. 
374
Absorbents of the Stomach.
 the lacteals,  quoted in page  106, from Mr. Cruikshank,
 was taken from a subject of this kind, of which an account
 is given in his work on the absorbing vessels, p. 59.
   It is worthy of note, that in several instances, in which
 the lacteals were  thus found distended with chyle, the
 glands in the mesentery were also uniformly white.


             The Absorbents of the Stomach
 Are of considerable size, and form three divisions. The ves-
 sels of the first set appear upon  both sides of the stomach,
 and pass through a few glands on the small curvature, near
 the omentum minus.  From  these glands they proceed to
 others, which are larger,  and which also receive some of
 the deep-seated absorbents of the liver.  The vessels from
 these glands pass to the thoracic duct, near the origin of the
casliac artery. The second arise also on both sides of the
 stomach, and pass  to the left extremity  of  the great cur-
 vature to  unite  with  the absorbents of that  side of the
great omentum. They then  proceed  with the lymphatics
of the spleen and pancreas, to the thoracic duct. The last
set pass off from the right  extremity of the great curva-
ture, and unite also with absorbents from the right portion
of the omentum. They proceed near the pylorus, and go
to the thoracic duct,  with some  of the deep-seated  ab-
sorbents of the liver.
   Although the absorbents of the stomach are deep-seated,
as well as superficial, it is a general sentiment,  that  they
do not contain chyle  in the human subject; notwithstand-
ing chyle has been found in the absorbents on the stomach
of dogs, and some other animals. It ought, however, to be
remembered, that  Sabatier has, in some instances,  seen
white lines on the stomach,  which  he supposed to be
lacteals. 
Absorbents of the Liver.
375
              The Absorbents of the Liver
Are especially interesting, because  they have been more
completely injected than those of any other viscus. They
are deep-seated and superficial. The  superficial it has been
already observed admit of injection in a retrograde direc-
tion, and, therefore, can be exhibited most minutely  ra-
mified. They communicate  freely with  each other,  and
also with  the  deep-seated vessels, by  their small ramifi-
cations; so that the whole gland has been injected from one
large vessel.
   The gland is so large, that the absorbents of the supe-
rior and inferior surfaces proceed from it in different direc-
tions.
   A large absorbent is generally found  on the suspen-
sory ligament. This is formed  by the union of a great
many branches that arise both on the right and left lobes,
but principally on the  right. It often passes through the
diaphragm at an interstice which is anterior to the xiphoid
cartilage,  and then proceeds through glands on  the anterior
part of the pericardium.
   Several absorbents proceed to the lateral ligaments on
each side, and then pass  through the diaphragm.  Some
of these branches return again into the abdomen, and the
others  generally run forwards in the course of the ribs,
and join those which passed up from the suspensory liga-
ment. The trunk, or trunks, formed by these* vessels, either
pass up between the laminae of the mediastinum, and ter-
minate  in the upper part of the thoracic  duct;  or they
accompany the internal mammary arteries, and terminate
on  the left side  in  the thoracic duct, and on the right in
the trunk of the absorbents of that side.
   The Absorbents on the concave side of the Liver are as
numerous as those on the convex side, they are also very 
376      Absorbents of the Liver and Spleen.
abundant on the surface of the gall bladder. The greatest
part of them join the deep-seated vessels.
  The Deep-seated Absorbents proceed in considerable
numbers from the  interior of the liver through the portae.
They accompany the biliary ducts and  the great  blood-
vessels of the  organ;  and,  after passing-through  several
glands, near the vena portarum,  terminate  in the thoracic
duct,  near the commencement of the superior mesenteric
artery.
  Mascagni states, that the absorbents of the liver  will be
distended, by injecting warm water into the biliary ducts,
or the vena portarum.
  He also  observes, that in those preparations  in which
the superficial vessels are completely injected, in the re-
trograde direction, the peritoneal coat of the liver appears
to be composed entirely of absorbent vessels; and to be
connected  to  the  membrane within, by many  filaments
which are also absorbent  vessels.


              The Absorbents of the Spleen
Are composed of superficial and deep-seated vessels;  but
they differ greatly from those of the liver, in this respect,
that the  superficial vessels are  remarkably small  in the
human subject.
  Mascagni however asserts, that when the bloodvessels
of the spleen are injected with size, coloured with ver-
milion, these absorbents will be filled with colourless size.
  In the spleen of the calf the superficial  absorbents are
remarkably large.
  In the human subject  the superficial absorbents of the
spleen proceed from the  convex to  the concave surface,
and there communicate with the deep-seated absorbents,
which proceed from  the interior of the organ with the
bloodvessels.
  These Deep-seated Absorbents are very numerous, and 
       Absorbents of the Pancreas. Thoracic Duct.   377

 also large. They accompany the splenic  artery; and in
 their course pass through many glands, some of which
 are said to be  of a dark  colour. The glands lie on the
 splenic artery, at a short distance from each other.  The
 absorbents of the spleen  receive  the absorbents of the
 pancreas in their course;  tliey unite with  the absorbents
 of the  stomach and the lower surface of the  liver,  and
 pass with them to the thoracic duct.
   Little has been  latterly said  by practical anatomists
 respecting


            The Absorbents of the Pancreas.
 Mr. Cruikshank once injected them in the retrograde di-
 rection; he found that they came out of the lobes of the
 pancreas in  short branches  like the bloodvessels, and
 passed  at right angles into the absorbents of the spleen, as
 they accompanied the artery in the groove of the pancreas.


             THE  THORACIC DUCT,
 Or common trunk of the absorbent system,  is formed
 by the union of those absorbent vessels which are collec-
 ted on the lumbar vertebrae.
   These vessels, as it  has been already  observed, are
 derived from various sources, viz.
   The Lower Extremities; the lower part of the Trunk of
 the Body; the Organs of Generation; the Intestines, with
 the other Viscera of  the abdomen  and pelvis, except a
part of the liver. Their number is proportioned to the ex-
twit of their  origin: for, with the numerous glands ap-
propriated to them,  they form  the  largest  absorbent
plexus in the body, and are spread over a considerable
portion of the aorta and  the vena cava.
  The manner in which these vessels unite to form the
  Vol.  II.                3 B 
 378      Commencement of the Thoracic Duct.

 thoracic duct, is very different in different subjects; but in
 a majority of cases it originates immediately from three
 vessels, two of which are the trunks of the absorbents of
 the lower extremities, and the other is the common trunk
 of the lacteals and the other absorbents of the intestines.
   These vessels  generally unite on the second or third
 lumbar vertebras; and, in some instances, the trunk which
 they form dilates  considerably,  soon after its commence-
 ment; in consequence of which it was  formerly called the
 RECEPTACLE of the CHYLE.  At first it "lies behind
 the aorta, but it soon  inclines to the right  of it, so as to
 be behind the right crus of the diaphragm. In the thorax,
 it appears on the front of the spine, between the aorta and
 the vena azygos, and continues  between these  vessels
 until it has arrived at  the fourth or third dorsal vertebra.
 It then inclines to the  left, and proceeds  in that direction
 until it emerges from the thorax, and has arisen above the
 left pleura, when  it continues to ascend behind the inter-
 nal jugular, nearly as high as the sixth cervical vertebra: it
 then turns downward  and forward, and,  after descending
from six to ten lines,  terminates in  the  back part of the
angle formed by  the  union of the  left  internal  jugular
with the left subclavian vein.  Sometimes, after rising out
of the thorax, it divides into two  branches, which unite
 before they terminate. Sometimes it divides, and one of
 the branches terminates at the  above mentioned angle, and
the other in the subclavian vein, to the left  of it.
  The orifice of the thoracic  duct has two  valves, which
 effectually prevent the passage  of blood into it from the
 vena cava.
  There are sometimes slight  flexures in the course of
the duct; but it generally inclines to  the left, in the upper
 part of  the thorax, as above mentioned;  and is then so
near the left lamina of the mediastinum, that, if it be filled
with coloured injection, it can be seen through that mem- 
Absorbents of the Lungs.           379
brane, when the left lung is raised up and pressed to the
right.
  The duct sometimes varies considerably in its diameter
in different parts of its course. About  the middle of the
thorax it has often been found very small. In these cases
it generally enlarges in its progress upwards, and is often
about  three lines in diameter,  in its upper part. Many
anatomists have observed it to divide and to unite again,
about the middle of the thorax.


               Absorbents of the Lungs.
  The absorbents of the lungs are very numerous, and,
like those of other viscera, are superficial and deep-seated.
  The large superficial vessels run in the interstices be-
tween the lobuli,  and therefore form angular figures of
considerable size. In successful injections, the vacancies
within these figures are filled up with small vessels, and
the whole surface appears minutely injected.
  Mascagni observes, that the superficial vessels are very-
visible when any fluid has been effused into the cavity of
the thorax; or when warm water is injected, either into the
bloodvessels of the  lungs,  or  the  ramifications  of the
trachea.  Cruikshank demonstrated them by inflating the
lungs  of a still born child;  in which case the air passes
rapidly into them.
  The deep-seated absorbents accompany the bloodvessels
and the ramifications of the bronchiae.  They pass to the
dark coloured glands, which are situated on the trachea at
its bifurcation;  and  on those portions of  the bronchiae
which are exterior to  the  lungs. The injection of the
absorbents, which pass to and from  these glands, seems
to prove that they  are  of the same  nature  with the ab-
sorbent glands  in general; notwithstanding their  colour.
They are numerous, and they vary in  size; from a diameter
of two lines, to  that of eight or ten. 
   380           Absorbents of the Lungs.

     From these glands, some of the absorbents of the left lung
■,  pass into the thoracic duct, while it is in the thorax, behind
   the bifurcation of the  trachea; others proceed  upwards
   and enter into it  near its termination; while those of the
   right lung terminate in the common trunk of the absorb-
   ents of the right  side. 
381
                    CHAPTER II.

   OF THE ABSORBENTS OF THE HEAD AND NECK; OP THE!
       UPPER EXTREMITIES, AND THE UPPER PART OF
               THE TRUNK OF THE BODY.

THE absorbents from the various parts of the head pass
through glands,  which are situated on the neck,  or the
lower part of the head.  Those on the head are the least
numerous, and also  the  least in size.  Some of  them,
which  are generally  small, lie about  the parotid gland.
Several of them, which are also small, are on the occiput,
below and behind the mastoid process. Sometimes there
are two or three on the cheek, near the basis of the lower
jaw, about the anterior edge of the masseter muscle. Be-
low the lower jaw, in contact with the submaxillary gland
and anterior to  it, there  are always a number of these
glands, which are generally small, but often swelled during
infancy.
   The Glands on the Neck are the most numerous. Many
of them  are within the sterno-mastoid muscle, and ac-
company  the internal jugular vein and the carotid artery
down to  the first rib. Many also  lie in the triangular
space between the sterno-mastoid muscle, the trapezius,
and the clavicle;  therefore it has been truly said that the
glands of the neck are more numerous than those  of any
other part, except the  mesentery.  They are frequently
called  Glandula Concatenata. It has already been men-
tioned  that the various absorbents, which are connected
with these glands, unite on each side into a trunk, which
on the  left passes into the thoracic duct, and on the right
into the common trunk of the absorbents of that side. 
3 82       Absorbents of the Head and Neck.
                     SECTION I.

        Of the Absorbents of the Head and Neck.
   There is the greatest reason to believe than the brain
and its appendages are supplied with absorbents like the
other parts. Some of these vessels have been discovered
in the cavity of the cranium; but very little precise infor-
mation has as  yet been obtained, respecting the extent,
or arrangement of the absorbent system, in this part of
the body.
   The absorbents on the exterior of the head are as nu-
merous as in other parts of the  body.  On the occiput they
pass down, inclining towards  the ear, and continue be-
hind it to the  side of the neck; behind the ear they pass
through several glands. From the middle or temporal
region of the  cranium, they pass with the carotid artery
before the ear, and  enter some small glands that lie on
the parotid; from  which they continue to the neck.
  They are on every part of the face, and unite, so that
their  principal trunks, which  are very  numerous,  pass
over the basis of the lower jaw, near the facial artery.
They enter into glands, which are also very numerous,
immediately under  the jaw,  or which  are sometimes
to be found on the cheek, at the anterior edge of the
masseter muscle. All the absorbents  of the exterior part
of the head pass to  the glands on the side of the neck,
already described.
  Those from the interior  of the nose  accompany the
ramifications of the internal maxillary artery, and  pro-
ceed to  glands behind the angle of  the lower  jaw; into
which glands also enter the absorbents of the tongue and
inner parts of the  mouth.
  The absorbents of  the thyroid gland, on the left side,
pass down to the thoracic duct; those on the right, unite 
Absorbents of the Hand and Arm.        383
to the trunk of the absorbents on that side, near its ter-
mination. It has been remarked that they can be readily
injected, by thrusting the pipe into the substance of the
gland.
                    SECTION II.

  Of the Absorbents of the Arm and Upper Part of the
                        Trunk.
  The absorbents of the arm are  superficial and deep-
seated, like those of the lower extremity.
  The superficial absorbents have been injected on the
anterior  and posterior surfaces of the  fingers  and the
thumb, near their sides.  On the back of the hand they
are very numerous,  and increase  considerably in  their
progress up the fore arm. As they proceed upwards, they
incline towards the anterior surface of the fore arm;  so
that by the time they have arrived at the elbow, almost all
of them  are  on the anterior surface. The absorbents  on
the anterior part of the hand are not so numerous as those
on the back.  Sometimes there are digital branches from
the fingers, and an arcus in the palm; but this bow is not
formed by one large  absorbent, analogous to the ulnar
artery. On the contrary, its two extremities are continued
over the  wrist, and pass on the fore arm like the absor-
bents.
  At the elbow, some of them  often pass into one or two
small glands, which are very superficial;  but the whole of
the absorbents, somewhat reduced in number, as some of
them unite together, pass along with the bloodvessels into
the hollow of the arm pit; where they enter  the  axillan
glands. There are  generally one  or more vessels which
pass in the course of the cephalic  vein, between the pec- 
384   Absorbents of the Upper Part of the Trunk.

toral and the deltoid muscle, and enter into some of the
glands under the clavicle.
  There are almost always several glands in and near the
axilla. Some of them are very near the great bloodvessels;
sometimes  one or more of them are much lower; some-
times they  are to be found under  the pectoral muscle.
They are commonly not so large as those  of the groin,
and are surrounded with fat.
  The deep-seated absorbents  originate  also at the fin-
gers, and soon accompany the branches of the arteries.
Those which attend the radial  artery, originate on tho*
back of the hand, and also in  the palm, where  they are
associated with the arcus profundus. They go up with the
radial artery to the elbow, and sometimes pass through
a small gland about the middle of the fore arm.
  Those which attend the ulnar artery, commence under
the aponeurosis palmaris, and  go with the artery to the
elbow; at the bend of the elbow they are generally joined
by one or more, which accompany the interosseal artery;
there they unite, so as to form several trunks which pass
up to the axilla with the humeral artery. They sometimes
pass  through  one  or two  glands, which  are  near the
elbow; and  they receive in their  course, deep-seated
branches from the muscles on the humerus.
  The absorbents from the anterior and external part of
the thorax,  and the upper part of the abdomen, also pro-
ceed to the axilla, and enter into the glands there;  those
which are deep-seated, joining  the deep-seated vessels.
The absorbents ofNthe mammae  pass to the same glands;
and when they are affected with the  virus of cancer, can
often be perceived, in their course, in the living subject.
  The absorbents of the uppermost half of the back, and
those of the back of the neck, go likewise to the axilla.
  The absorbent vessels,  collected from  these various
sources,  proceed from  the  exterior to the  innermost
glands, but  with a considerable  diminution  of their num- 
          Facts relating to Cutaneous Absorption.     335

 ber; they accompany the subclavian vein, and are reduc-
 ed to one or two trunks, that generally unite before their
 termination. On the left side, the absorbents of the head
 and neck generally open into the thoracic  duct, as has
 been already  observed; and those of  the left arm  also
 open into the  thoracic duct, or into  the subclavian  vein
 very near it. On the right side the absorbents from each
 of these parts empty  into  the common trunk, which
 often is  formed by the union of large vessels, from  four
 sources; viz. the Head, the Thyroid gland, the right Arm,
 and the right cavity of the Thorax, &c. The diameter of the
 trunk is very considerable; but it is  often not more than
 half an inch in length. It generally opens into  the right
 subclavian vein,  at the place where it unites to the right
 internal jugular.

     Two respectable physiologists of Europe (M. Seguin, of
       Paris, and the late Dr. Currie,of Liverpool) have doubted
       whether absorption takes place on the external surface of
       the skin.*—This question has been examined in a very
       interesting manner by several graduates of the university
       of Pennsylvania, who chose it for the subject of their in-
       augural theses; viz. Drs. Rousseau, Klapp, Daingerfield,
       Mussey,  and J. Bradner Stewart.
    _ The  three first of these gentlemen state, that when spirit of
       turpentine, and several other substances which are com-
       monly supposed to be absorbed by the skin, were applied
       to  it in a  way which  prevented their  volatile parts from
       entering the lungs by respiration, no absorption took place.
       But when they inspired air impregnated with exhalations

  * I believe that M. Seguin's Memoir on this  subject was read to
the Academy of Sciences a short time before the meetings of that
body were  suspended. It was published  by M. Fourcroy, in La Me-
dicine Eclairee par les Sciences Physiques, vol. iii.—An extract from
M. Fourcroy'a publication may be seen in the 19th chapter of the first
volume of Dr. Currie's " Medical Reports on the Effects of Water,"
Sec, in which is also contained,  a statement of the  Doctor's own expe-
riments and reflections.
  Vol. II.               3 C 
j86   Experiments of K. Boerhaave and J.  Hunter.

       from these substances, they perceived satisfactory proofs
       that the exhalations entered the system. From these facts
       they inferred that when those articles entered the body
       by-absorption, they were taken in by the lungs, and not
       by the external surface.
     On the other hand, the two gentlemen last mentioned, state
       that after immersing themselves in a bath consisting of
       a decoction of rhubarb, of madder, or of turmeric, their
       urine became  tinged with these substances. They also
       assert that the colouring matter of these different articles
       is not volatile; and, therefore, could not have entered the
       lungs during the experiments.*
     The statemept in page 364, from  Dr. Soemmering, that
       when mercury  is injected  backwards in the  absorbent
       vessels which  originate  on  the foot, it  will sometimes
       appear in small globules on the skin  of  the foot, has an
       important connexion with  this subject.f
    About the middle of the last century, it was generally be-
      lieved by anatomists, that absorption was performed by
      the veins. This doctrine seemed to be established by the
      experiments of Kaaw Boerhaave, which are related, with
      many other interesting statements, in his work entitled
      " Perspiratio Dicta Hippocrati," &c, published  at Ley-
      den, in  1738. In these  experiments it appeared to the
      author, that when the stomach of a dog was emptied of
      its contents, and filled  with warm water, immediately
      after  death, the water passed into the minute ramifica-

  *The  Thesis of Dr. Rousseau was published in 1800. Those of
Drs. Klapp and Daingerfield in 1805. Dr. Mussey published in the
Third Supplement to the Medical and Physical Journal of Dr. Barton,
in 1809. Dr. Stewart published in 1810—Additional observations by
Drs. Klapp, Rousseau and Smith, are published in the  Philadelphia
Medical  Museum, Vol. I. new series.
  t Since the publication of the first volume, the author has enjoyed
the advantage of consulting a translation, in manuscript, of some parts
of the German edition of Dr.  Soemmcring's valuable work on the
Structure of the Hturran Body, 
Experiments of Magendie and Delile.      387
        tions of the veins of the stomach, and from them to the
        vena portarum,  and  ultimately to  the heart, in  large
        quantities.
     This account appears to be disproved by some experiments
        of the late John Hunter, made about twenty years after,
        and published in the  Medical Commentaries  of  Dr.
        William Hunter, Part I.——Mr. Hunter's experiments
        have been considered as establishing the fact, that absorp-
        tion (in the  intestines at  least) is performed exclusively
        by the lacteals, or proper absorbent vessels, and not at all
        by the veins.  Kaaw Boerhaave is  of course supposed to
        have been mistaken; and Mascagni, who has repeated
        his experiment, refers the appearance  of wajter in the
        veins to transudation, through the coats of the intestines,
        which he has observed to take place to a great degree.
     In the  year 1809, a memoir was presented to the national
        institute of France by Messrs. Magendie and Delile,
        which  contains an account of some experiments that have
        an important relation to the above mentioned subject.*
        —The authors  being  greatly surprised at the rapidity
        with which the poison of Java, &c. appeared to enter the
        sanguiferous system, instituted a series of experiments
        to determine  whether these  substances  proceeded to
        that system by the circuitous route of  the  absorbent
        vessels, or by the shorter course of the veins. Two of
        their experiments are especially interesting. They made
        an incision  through the parietes of the abdomen  of a
        living  dog, who had eaten a large quantity of meat some
        hours before (that his lacteals might be visible from their
       distention with chyle), and, drawing out a portion of the
       small intestine, they applied  two  ligatures to it, at the
       distance of five inches  from each other. The portion of
       intestine between these ligatures was then separated by
        incision from the rest of the intestinal tube, and all the
       lacteals, bloodvessels, &c. which passed to and from it,
       were divided,  except one artery and  a vein. A consider-

  • The title of the paper is a " Memoir on the Organs of Absorption
in Mammiferous Animals." A translation of it  was published in the
Medical and Philosophical Register of New  York, and  in several
other periodical works. 
388      Experiments of Magendie and Delile.

      able length of this artery and  vein were detached from
      all  the surrounding  parts, so that the authors supposed
      these vessels to form  the only connexion between  the
      portion of the intestine  and the rest of the body. Into
      the cavity  of the intestine, which was  thus  circum-
      stanced, they introduced a small quantity of the poison,
      and, to their astonishment, it  produced its fatal effects
      in the same manner it would  have done if it had been
      introduced into  the  intestine  while all its connexions
      with the body were entire. This experiment, they assert,
      was repeated several times, without  any difference in
      the result.
    After several other experiments, they finally separated the
      thigh from the body  of  a living dog in such a manner
      that the crural artery and vein were left undivided. A
      quill was then introduced into the artery, and two liga-
      tures were applied  to fix it round the quill. The artery
      was then divided between the ligatures. The vein was
      managed in the same manner.  There  was, therefore, no
      communication between the limb and the body, except
      by the blood which  passed  through the divided vessels
      and the quills. The  poison was then introduced under
      the  skin of the foot, and soon occasioned the death of the
      animal:  its  deleterious  effects  commencing about four
      minutes after its  application to  the foot. This experiment
      appears to prove decidedly that the  blood  is the vehicle
      by  which poison, when applied to  the extremities, is
      carried to the body;  although  it may not determine  the
      question whether this poison was taken up by the absor-
      bents or by the veins.
    Some  other experiments made by the authors gave results,
      which are very difficult indeed  to explain.  They wished
      to know if  the blood of an animal thus contaminated,
      would produce similar effects upon another animal; and,
      with a view  to  ascertain this point, they insinuated a
      small piece of wood, covered with  the poison, into the
      thick part of the  left side of the nose of a dog. Three mi-
      nuses after the introduction of the poison, they transfused
      blood from  the jugular vein of  the same side, into one of
      the  veins of another dog.  About one  minute  after the 
Report of the Committee of the Institute.     389
      commencement of the transfusion, the effects of the poison
      began in the dog to which it was applied, and continued
      until his death.  Transfusion into the veins of the other
      dog went on during the whole time, and he received a
      large quantity of blood from the dying dog, without pro-
      ducing any effect.—They varied this experiment in the
      following manner.  The thigh of a dog  was separated
      from the body; the artery and  the vein were arranged
      as in the former experiment; and poison was introduced
      into the foot. Three minutes after the introduction o£ the
      poison, the blood of the crural vein was passed into the
      jugular vein of another animal, and transfusion was con-
      tinued five minutes without producing any effect upon the
      animal receiving the blood: it was then stopped, and the
      crural vein was so arranged that the blood flowed from
      it into the animal to which it belonged.  This animal very
      soon exhibited symptoms of the operation of the poison.*
     From these very interesting experiments the authors infer
      that "foreign matters do not always proceed through the
      Lymphatic or Absorbent Vessels, when they enter into the
      Sanguiferous system."
     This memoir was referred  by the Institute to four of its
      members, who are particularly distinguished by their pro-
      found knowledge of anatomy and physiology. These gen-
      tlemen, after stating their belief that the functions of the
      lymphatic or absorbent system have been completely as-
      certained by the experiments and observations of Hunter,
      Cruikshank,   Mascagni, &c, say  further, that, in their
      opinion, the  above mentioned inference ought to be a
      little modified, and that facts are not sufficiently nume-
      rous, or applicable to the  point in question, to justify the
      inference that foreign matters  do not always proceed
      through  the Lymphatic or Absorbent  Vessels, when they
      enter the Sanguiferous system.  But they also add, that,
      as the author is still engaged in a series of experiments

  * An account of these experiments was published by M. Magendie
in a pamphlet. A statement of  them is also contained in the report
made to the Institute by the committee to whom  the memoir was
referred, which  is published in the Journal de Physique, for March
IS 13. In that statement this last mentioned experiment is omitted. 
390           Of the Absorbent System.
on the subject, they will suspend their judgment res-
pecting the inferences to be deduced from the present
statement.
The most extensive account of the absorbent system is con-
  tained in the " Historia et Ichnographia Vasorum Lym-
  phaticorum Corporis Humani"  of Mascagni.—"The
  Anatomy of the  Absorbing Vessels of the Human  Body,
  by W. Cruikshank;"—and "The Description  of the
  Lymphatic  System,  by  Wm. Hewson,"  (the second
  volume of his Experimental Inquiries)—are also very
  interesting publications. 
SYSTEM OF ANATOMY.
APPENDIX. 
 
APPENDIX.
                   OF THE BLOOD.

 I HE blood of a healthy person  indicates a tendency to
 coagulate very soon after it is discharged from the vessels
 which naturally contain  it, although it is perfectly fluid
 in those vessels.
   If it remains at rest, after it is drawn from the vessels,
 it soon  coagulates into  a solid mass, of  a soft texture.
 From this solid mass a fluid is soon observed to issue,
 which first appears in very small drops on almost every
 part of the surface. These drops quickly increase and run
 together, and in a short time the fluid surrounds the solid
 mass, and exceeds it in quantity.
   The solid  part  wr^ich thus  appears upon the sponta-
 neous separation of the blood, is denominated  Crassa-
 mentum or Cruor: the fluid part is called Serum.
   The substance  which contains the  red colour of the
 blood remains with the Crassamentum. The Serum, when
 it separates without agitation, is free from the red colour.
   The  colouring  matter  may  be separated completely
from the Crassamentum by washing it with water.
  The blood, therefore, consists of three parts, viz. the
Serum; the Substance which coagulates spontaneously; and
the Colouring Matter.
  Vol. II.             3 D 
o^l           Appendix.—Of the Blood.
                     THE SERUM
Has a considerable degree of consistence, although it is
much thinner than blood. In its perfectly natural state, it
is almost transparent, and appears to be very lightly ting-
ed with a greenish yellow colour; but it  is very often im-
pregnated with a portion of bile, which is probably carri-
ed to the bloodvessels by the absorbents. It contains a large
quantity of albumen, or matter like the white of  an egg.
If heated  to 140°  of Fahrenheit, it becomes opake; and
when the heat is increased to 156 or 160, it is firmly co-
agulated.  It  is also coagulated by alcohol, by  mineral
acids, and  by rennet.*  It is proved by  chemists, that it
contains a small quantity  of pure  soda. It therefore
changes several of the blue colours of vegetables green.
It is also found to contain a similar quantity of the mu-
riate and the phosphate of soda, and the phosphate of lime.
These saline  substances  were discovered  by  diluting
serum with water, and exposing the mixture to heat,  by
which the albumen  was coagulated into flocculse: these
flocculae were separated by  filtration:  the liquor was then
diminished by evaporation, and  the salts obtained from it
by crystallization.
  Serum likewise contains a portion of sulphur combined
with ammonia.
  When it is exposed to a coagulating heat, a small por-
tion of it remains fluid.
  This fluid portion has been supposed  to contain a con-
siderable quantity  of gelatine; but it is contended by Mr.
Brande,f  that Gelatine does not exist in the serum of the

  'See  Hewson, Vol. I. p. 139.—I  suspect that some  particular
management is necessary in the use of rennet.
  t  In his Researches on the Blood, communicated to the  Royal So-
ciety of London in 1812, and republished in the Eclectic Repertory
for April 1813. 
Appendix.—Of the Blood.
395
 Ldood, and that this portion consists of albumen combined
 with a proportion of alkali.
   It is also asserted by  Dr. Bostock,* one of the latest
 writers on the subject, that the serosity of the blood (the
 term applied to the last mentioned fluid) contains no ge-
 latine; but that, with a minute quantity of albumen, it
 consists of a large portion of an animal matter, which is
 different either from gelatine or  albumen, being unlike
 either of them in its chemical qualities.


                 THE  CRASSAMENTUM
 Is rendered very different in its  appearance, by the dif-
 ferent circumstances in which it may coagulate.
   When the blood remains at rest immediately after it is
 drawn, the crassamentum which forms in it is a concrete
 substance, without the smallest appearance of fibre in its
 composition. If the blood is stirred with a rough stick,
 while it is flowing from an animal, a large portion of it
 will concrete upon the stick in a fibrous form, so as to
 resemble  a mass of entangled thread, some  of the red
 colouring matter still adhering to it.
   The crassamentum, in either of these forms, may be
•washed perfectly white; the red colouring matter passing
 Completely away with the water. In this state  it appearsf
 to have all the chemical  properties of  the fibrous matter
 of muscular flesh.  It also resembles the gluten of vegeta-
 bles, being soft and elastic.  The name fibrin  is now
 generally  applied to it.
   If fibrin is washed and dried, its weight is very small
 indeed when compared with that of the blood from which

   * See his Observations on the Serum of the Blood, in the Medico-
 Chirurgical Transactions, Vol. II, republished in the Eclectic Re-
 pertory, for October 1812.
   t By the  experiments of Mr. Charles Hatchett, published in the
 London Philosophical Transactions for  1800. 
 396           Appendix.—Of the Blood.
 it has been obtained. It is, therefore, probable that a con-
 siderable proportion of the bulk of the crassamentum, fs
 it forms spontaneously, depends  upon the serum  which
 exists in  it, and can be washed away.
   The spontaneous coagulation of the blood, which ap-
 pears to depend principally upon the Fibrin, may be pre-
 vented by the addition of several foreign substances to the
 blood, when it is drawn. It is subject to great variations
 that  depend upon the  state  of the  body at  the time of
 bleeding; and in some conditions, it does not take place
 at all.*
   In a  majority of dead subjects the blood is found more
 or less  coagulated in the veins; but in some subjects it is
 found without coagulation. It is asserted that it does not
 coagulate in subjects who have died suddenly, in conse-
 quence of anger, lightning, or a blow on the stomach.


              THE COLOURING MATTER.
   When  the bloodvessels in the transparent  parts  of
 certain  living animals  arc examined  with  magnifying
 glasses, it appears that the red colour of the blood is owing
 to bodies of a globular form,  which are diffused through
 a transparent fluid. The appearance of these bodies has.
 been examined, with great attention, by many physiolo-
 gists,  since the publication  of Leuwenhoeck,  in  the
 London Philosophical Transactions, f

  * See an Inquiry into the Properties of the Blood, by the late Wm.
Hewson: and Experiments by his son, T. T. Hewson, in the Eclectic
Repertory,  Jan. 181 I.—See also a Treatise  on the Blood, &c. by the
late J. Hunter.
  t Among the most distinguished of  these observers were Father
de la Torre, Haller, Hewson, Fontana, Spalanzani, J. Hunter, Cavallo.
  Some  short accounts of Leuwenhoeck's original observations on
the blood are to be found in  the Philosophical Transactions of Lon-
don, for 166i, in the fasciculi which are numbered 102 and  106. A
more full description is contained in Boerhaave's Academical Lee- 
                Appendix.—Of the Blood.            397

   Several of these gentlemen have described the appear-
 ance of the blood very differently;  but Haller, Spalanzani
 and J.  Hunter agree that the  figure of the red particles is
 globular.* Hunter observes further, that the red globules
 do not  run into each other as two globules of oil would do
 when divided by water; and he believes that they cannot
 unite. At the same time they seem not to have the pro-
 perties of a solid: for when circulating in the vessels, they
 assume elliptical forms, adapting themselves to the size of
 the vessels.  They also excite no  sensation  of solidity
 when touched.
   They appear to be more heavy than the other parts  of
 the crassamentum: for  in  healthy blood the lower part  of
 the mass contains more of the colouring matter than the
 upper part; and in the blood of persons who labour under
 acute local inflammation,  they  often  subside completely
 from the upper part;  and thus occasion what is called, by
 Mr. Hewson, the infiammatory crust, or size.
   It has  been observed by Mr.  Hewson, and also by Mr.
 Hunter, that the globules do not retain their form in every
 fluid. They are said to be dissolved very quickly in water,
 and then they form a  fine clear red. Several of the neutral

 tures on the Theory of Physic. See the section on the nature of the
 blood.
  The glasses of Father de la Torre were transmitted from Naples to
 the Royal Society of London in 1765. They were accompanied by a
 letter from Sir F. H. E. Stiles, to which are subjoined some observa-
 tions by the Rev. Father himself. The letter and the observations are
 published in the 55th volume of the transactions of that society.
  In the year 1798, Tiberius  Cavallo published an Essay on the
 Medicinal  Properties of Factitious Air, with an appendix on the
 Nature of the Blood; in which  is contained a further account of the
 glasses of De la Torre.
  * I believe that this is also the opinion of Fontana.—In J. Hunter's
 work on  the Blood there are some interesting observations on micro-
scopical deceptions. See the note, commencing in page 39, Bradford's
edition. 
398            Appendix.—Of the Blood.
  salts, when dissolved in water, prevent the solution of the
  globules.  Mr Hunter informs us, that the vitriolic acid,
  when greatly diluted,  does not  dissolve them, &c.  The
  muriatic acid, when three times as strong as vinegar,
  destroys their colour  without dissolving them, although
  when more diluted, it dissolves them.
    The colour of the blood has, for a long time, been sup-
  posed to depend upon Iron.  About the middle of the last
  century, Vincentius Menghini published in the Transac-
  tions of the Academy of Sciences of Bologna, an account
  of experiments which  contributed to establish this senti-
  ment. In this account he  stated, that, after washing the
 colouring matter from the  crassamentum, he had sepa-
 rated it from the water by boiling; in which case it either
 rose to the surface of the water, or subsided, and  left the
 water clear. After drying, with a gentle heat, some of the
 colouring  matter thus separated,  and  then  repeatedly
 washing it, he found  that it contained  a considerable
 quantity of iron, which was attracted by  the magwet.
   After exposing a large quantity of the colouring matter
 to  an intense  heat, he found in it a small piece of iron, of
 a spherical form, but  hollow; and a powder which was
 attracted by the magnet, but appeared more like  rust of
 iron than iron  filings.
   He believes the seat of this iron to be in the colouring
 matter of the blood,  as  neither the serum  nor  fibrina
 appeared to contain it.—According to his calculation, the
 blood of a healthy man contains more than two ounces of
 iron,.
  This doctrine  of Menghini has been  very generally
admitted; and several chemists of the first character, viz.
Bucquet, Fourcroy, Vauquelin,  he. have made experi-
ments to ascertain the substances with  which the  iron in
the blood is combined.
  But within a few years,  doubts have been  expressed 
             Appendix.—Of the Blood.             399

on this subject by several physiologists, and especially bv
Dr.  Wells, and Mr. Brande.
  The first of these gentlemen, in his " Observations and
Experiments on the Colour of the Blood," published in the
London Philosophical Transactions for 1797, states three
reasons for rejecting the opinion that the colour of the
blood is deriyed from iron.
   1. The colour of blood is destroyed by a heat less than
that of boiling  water: whereas no colour arising from a
metal is destroyed by exposing its subject, in a close ves-
sel,  to such a heat.
   2. If the colour from a metal,  in any substance, be
destroyed by any alkali, it may be  restored by the imme-
diate addition of an acid; and the like will happen by the
addition of a proper quantity  of an alkali, if the colour
has  been destroyed  by an acid.  The colour of blood, on
the  contrary, when once destroyed, can never be brought
back, either by an acid or an alkali.
   3. If iron  be the cause of the red colour of blood,  it
must exist there in a saline state;  since  the red matter
is soluble in water.  The substances, therefore, which de-
tect the smallest quantity of iron  in such a state, ought
likewise to demonstrate its presence in blood;  but upon
adding Prussian alkali, and an infusion of galls, to a very
saturated solution of the red matter, he could not observe
"in the former case the slightest blue precipitate; or in
the  latter that the  mixture  had acquired the  least blue
or purple tint."
   Mr.  Brande,  in a paper entitled " Chemical Researches
on the Blood." &c. communicated to  the Royal Society of
London in 1812, relates many experiments which were
made  on the colouring  matter of that fluid, with acids,
alkalies, astringents, &c. &c.  From these  experiments
he also infers, that the colouring matter of the blood Is
perfectly independent of iron.
   In support of this inference, he adds, that the Armenian 
 400       Appendix.—Structure of Glands.

 dyers, in the preparation of their finest and most durable
 red colours, use blood in addition to madder, in order to
 insure the permanency of these colours. As the compounds
 of iron convert the colour of madder to grey and black,
 the production of a  bright  colour, by the addition of
 blood to  madder, he  regards as a proof, that iron  is not
 the colouring matter of blood.
   Many estimates have  been made of  the  quantity of
 blood in the human body; but some of the best informed
 plvysiologists have regarded them as fallacious.


              STRUCTURE  OF GLANDS.
   Any original structure that discharges from the blood-
 vessels  a fluid  different from those which they naturally
 contain, may be considered as glandular. The function or
 process by which such fluids are derived from the blood-
 vessels is called secretion.
   A structure of this kind seems to exist in very different
 situations: for it  is distinctly circumscribed in many of
 those bodies commonly denominated glands, which  are
 of a very precise form; and it  is also diffused  on  some
 very  extensive  surfaces. The gastric liquor, a most im-
 portant  secretion, is  probably discharged from vessels
 which open, like exhalents, on the internal surface of the
 stomach; and not from any circumscribed bodies, which
 are generally denominated glands.
   The name of gland is  theoretically applied to several
 bodies which cannot be proved to secrete any fluid*what-
 ever; and also to those bodies connected with the- absor-
 bent vessels, which are called the Lymphatic Glands; but
 it is most commonly appropriated to those organs which
 discharge a fluid different from the blood.
  The structure  by  which mudus is secreted  in some
places, appears  to  be  very simple. Thus in the Schnei-
derian membrane and the urethra, there are small ducts 
            Appendix.—Structure of Glands.        401
from four to six lines in length, and equal in diameter to
a bristle, which appear to be formed of the membrane or»
which they open. From these ducts mucus issues to cover
the surfaces of these membranes. In many instances there
is no substance  resembling that  of  the circumscribed
glandular bodies,  connected with these ducts;  but the
secreted fluid  seems to be discharged  into the ducts from
the  small vessels on  their surfaces.—The ducts of  this
nature in the urethra are denominated Lacuna.
   In some other parts of the body, the cavities  into which
mucus is discharged are somewhat different, both in form
and size, from  those above mentioned,  and  are called
Follicles. These  cavities  are  surrounded  with  more or
less of a pulpy vascular substance, which has been con-
sidered as glandular, and essential to  the mucous secre-
tion.
   The circumscribed bodies, which are commonly called
glands,  differ  in  their internal appearance and  texture,
from the other parts of animals. The substance of which
they consist differs very much  in the different glands; and
thus renders the liver, kidneys, salivary glands, mammas,
&c, very different from each other. Some glands, as the
salivary, &c, are composed of several series of lobuli that
successively diminish. The smallest of these are denomi-
nated Acini. Each of them is connected by a small artery
and vein, to the large bloodvessels of the gland;  and also
sends a branch to join the excretory  duct.  These Acini
are therefore connected to each other, by the bloodvessels
and  excretory duct of the gland, and also by the cellular
membrane, which covers them externally, and occasions
them to adhere to each other where they are in  contact.
In  consequence of  this  structure, these glands have  a
granulated appearance.
  The* liver, when inqpseg with a sharp  instrument, ap-
pears differently; but when broken into pieces, it seems
  Vol.  II.              3 E 
402       Appendix.—Structure of Glands.

to consist of small acini. Some other glands, as the Pros-
tate, appear to be uniform in their texture, and have none
of this granulated appearance.
   The structure of glands has  long  been an interest-
ing object  of anatomical  inquiry, and was investigated
with great  assiduity by those  eminent anatomists,  Mal-
pighi and Ruysch.
   Malpighi,  as was  formerly observed,  used  ink and
other coloured fluids in his injections.  He was also very
skilful in the  use of microscopes, and took great pains in
macerating and preparing the subjects of his inquiries.
Ruysch,  on the other hand, used a  ceraceous injection,
and was  most eminently successful  in filling very small
vessels with  it.  Malpighi believed that  there were fol-
licles or  cavities in glandular  bodies, which existed be-
tween the extremities of the arteries and the commence-
ment of the excretory ducts of those bodies, and that in
these cavities the secreted fluids underwent  a change.—
Ruysch contended,  that the arteries  of glands were con-
tinued into excretory ducts without the intervention of any
cavity or follicle; that the small  bodies, which had been
supposed to contain follicles or  criptas, were formed by
convolutions  of vessels, and that the change of the fluid,
or the process of secretion, is produced  by the  minute
ramifications  of the  artery.
   A very interesting account of this subject is contained
in two celebrated letters, which passed between Boer-
haave and Ruysch in the year 1721, and are published at
the end of the fourth volume of the works of Ruysch.
   The opinion of Ruysch has been most generally adopt-
ed by anatomists, and has derived support and confirma-
tion from several anatomists since his time.—The late
Mr. Hewson  declared his conviction that the small glo-
bular bodies  which are scattered through the kidneys,
and were supposed  to  be follicles or criptae, are merely
convoluted arteries.  He also asserted, that the acini which 
            Appendix.—Structure of Glands.       403

appeared in the mammae as large as the heads  of pins,
when  the excretory ducts of that gland were  injected
with vermilion and painters' size, proved to be the mi-
nute ramifications  of the excretory duct, which  divided
very suddenly into branches so  small, that they could
not  readily be seen by the naked eye.*
   Notwithstanding these  reasons for supposing that the
excretory ducts of glands were derived simply from the
arteries  of those  bodies, it is said that  the  late  Dr. W.
Hunter  used  to declare his belief,  that there was a part
in glands which was not  injected,  in  his  preparations;
and to say further, that he believed  his preparations were
injected as minutely as those of Ruysch.
   All  of these opinions have been strenuously contro-
verted by the Italian anatomist, Mascagni, who  believes
that the arteries terminate only in veins;  and of course
that they neither  form exhalent vessels, nor communi-
cate with the excretory ducts of glands. His idea of the
structure of glands is different from those either  of Mal-
pighi or  of Ruysch. He supposes that glands contain a
great number of  minute cells; that the arteries, veins,
and absorbent vessels are spread upon the surfaces  of
these cells,  in great numbers, and very irregularly. From
these cells  very  small  canals originate, which unite  to
form the small branches of the excretory ducts. Accord-
ing to his idea, the secreted fluid  is discharged through
pores or  orifices of the bloodvessels, into the cells, and
proceeds from them, through the canals, into the branches
of the excretory ducts. Absorbent vessels,  in great num-
bers, originate from these cells.
  In his great  work on  the absorbent system, when
treating  on the termination  of arteries and the com-
mencement of veins, (Part I. Section 2.) he asserts, that
if the  kidneys are successfully injected with size, co-

          • See Experimental Inquiries, vol ii. p. 178. 
404        Appendix.—Structure of Glands.

loured with vermilion, and then  laid open by a scctiou
with a razor,  it will  be found that the  size without the
colour has passed into cells, which  are very numerous;
that the arteries and  veins are ramified most minutely on
the surfaces  of these cells, and that the tubuli uriniferi,
as well as the absorbent vessels, originate from them.
   He supposed that a considerable portion of the fluid
thus  passing off from the  bloodvessels,  is  commonly
taken up by  the absorbent vessels of the kidneys: for in
two  cases in which  he found the absorbent vesstls  ob-
structed, a diabetes  existed, which he considered as the
effect of the inactivity of the absorbents. He asserts,  that
in the liver,  pancreas, mammas,  and  also  in  the sali-
vary and lachrymal glands, the minute arteries and veins
are also  distributed  upon the surfaces of cells; and  that
very  small  canals arise  from  these  cells,  and unite to
form the small branches of the excretory ducts.
   This great anatomist  appears to have been much oc-
cupied with  microscopical observations, and has gone
largely into the discussion of this subject.*

     It must, however, be acknowledged, that  no  information
       which has as yet been obtained respecting the structure
       of glands, enables us  to explain their wonderful effect
       upon the fluids which  pass through them. It remains
       yet to  be ascertained why one structure forms saliva and
       another bile; or why so much apparatus should be neces-
       sary for the secretion of milk, when  adipose matter ap-
       pears to be  produced by the mere membrane in which it
       is contained.

   *Tbe late Dr. W. Hunter, in his Medical Commentaries, (p. 40,)
 avowed his belief, that  the fluids, which appear occasionally in the
 various cavities of the body, transude through the coats of the blood-
 vessels. Mr Hewson (Experimental Inquiries, Vol. II. Chap. 7.)
 suggested several reasons for dissenting from this opinion; but Mas-
 cagni has endeavoured  to support it—See a long note to the above
 mentioned section of his work, page 74. 
           Appendix.—Structure of Glands.         405

    Dr. Berzelius,  professor of chemistry at Stockholm, in a
      late work on animal chemistry, asserts, that if all the
      nerves going to a secretory organ are divided, secretion
      will cease, notwithstanding the  continued circulation of
      the blood. From this, he thinks, that secretions depend
      upon the influence of nerves, although he cannot explain
      their effect.
    Mr. Home, after relating some experiments upon blood
      and serum, made  with the Voltaic Battery, proposes the
      following questions, among others:  Whether a weaker
      power of electricity than any which  can be kept  up by
      art, may be capable of separating from the blood the dif-
      ferent parts of which it is composed; and forming new
      combinations of the parts  so separated?—Whether the
      structure of the nerves may enable them to possess a low
      electrical power, which can be employed for that purpose?
       &c.
           See  the  London Philosophical Transactions, for
              1809, Part II.*

  •Mr. Wollaston has also published a small paper on this subject,
in the Philosophical Magazine, Vol. 33. 
 
           GLOSSARY,





               EXHIBITING






The Derivation of certain Anatomical Terms. 
 
GLOSSARY/
EXHIBITING THE DERIVATION OF CERTAIN ANATOMICAL
                        TERMS
                            A.
ACETABULUM. The  cavity which receives the head of the
  thigh-bone; from acetum vinegar: so called, because it repre-
  sents the acetabulum or saucer of the ancients, in which vine-
  gar was held for the use of the table.
Acini. From acinus a grape.
Acromion. A process of the  scapula; from «*pe« extremity, and
  «ft»i the shoulder.
Anastomo&is. The  communication of vessels with one another;
  from «vx through, and ropx mouth.
Anatomy. The dissection of  the human body; from «»*, and ti^vo
  to dissect.
Anconeus. A muscle; so called from etyxai the elbow.
Aorta. Aayrjj; from *ng air, and mpa to keep.
A/ioneuro&is. A tendinous expansion; from «to, and Kvpev a nerve;
   from an  erroneous  supposition of the ancients, that  it was
   formed by an expansion of nerve.
A/io/ihysis.  A process of a bone; from ecT»j)va> to proceed from.
   A synonyme of process.
Arachnoides. A net-like membrane; from «/>«#vu a spider, andteJej
   likeness.
Artery. From «*g air, and mpo to keep; because the ancients sup-
  posed that air only was contained in them.
Arthrodia. A species of connexion of bones; from «p0p« to articu-
   late.
Arytxnoidts. The name of two cartilages of the larynx; also ap-
   plied to some muscles of the larynx; from  apvTxm* a funnel,
   and ulot a shape.

                        * By Dr. Hooper.
   Vol. II                   3 F 
410                      Glossary.

Astragalus. A bone of the tarsus; so called from its resemblance
  to a die used in ancient games, from aroxyxXos a cockal or die.
Atlas. The first vertebra of the neck; so called, because it sustains
  the head: from the fable of Atlas being supposed  to have sup-
  ported the world; or from «ta*» to  sustain, because it sustains
  the head.
Azygos. A term applied  to parts without a fellow, from « priv. and
  £tya« a yoke, because it has no fellow.

                              B.
Bursa. A bag; from flvprx: generally applied to the bursae muscosae.

                              C.
Cancelli.  Lattice  work; generally applied to the rccticular substance
  in bones.
Cardia. The superior  opening of the stomach; from xxfiix the
  heart.
Carotid. The name of some arteries of the neck and  head;  from
  *«r'oi) to cause  to  sleep;  for, iP* tied with a ligature, the animal
  was said to be  affected with coma.
Carjius. K^pxojj the wrist.
Clavicula. The clavicle or collar-bone,  a diminutive of clavis a key;
  so called from its resemblance to an ancient key.
Clinoid. Four processes of the sella  turcica of the ethmoid  bone
  are so called, from *A«»« a bed, and  hmj likeness;  from  their
  supposed resemblance 10 a couch.
Clitoris. 'A part  of the female pudenda, enclosed by the labia ma-
  jora; from *.Xuu to enclose or hide.
Colon. The first  of the  large intestines; from x.uX»v, quasi xo/Aar,
  from xojAos hollow.
Coracoid. From xoga|a crow, and t;2oe resemblance; shaped likethe
  beak of a crow.
Coronary. From  corona a crown. The vessels  of the heart, sto-
  mach,  &c. are so called because they surround the parts in the
  manner of a crown.
Cotyloid. From ttarvXn the name of an old measure, and e* J«? resem-
  blance; resembling the kotule.
Cranium. The skull; x.fxno*, quasi **p«n«», from  x.xpx the head.
Cremaster. A muscle so called; from x^t^xu to suspend, because it
  suspends the testicle.
Cribriform. From cribrum a sieve, it being perforated like a sieve. 
Glossary.                     411
Cricoid. Annular, round like a ring; from xg<K»$ a ring, and «.?<,<
  likeness.
Cuboides. A bone of the foot; from *t»£«s a cube, and «/3oj likeness;
  because it resembles a cube.
Cuneiform. Some bones are so  called; from  cuneus a wedge, and
  forma likeness; being shaped like a wedge.

                              D.
Deltoid. A muscle resembling the Greek letter A; from A4 and {j3as
  resemblance.
Diaphragm. The muscle which separates the thorax from the ab-
  domen; from itx^xT% to divide.
Diarthrosis. A moveable connexion of bones; from 3<«gdgaA> to arti-
  culate.
Digastric. From hi twice, and yx?*£ a belly;  having two bellies.
Di/iloe. The spongy substance between the two tables of the skull;
  from "hmXou to double.
Duodenum. The first portion of the small intestines; so called be-
  cause the ancients supposed that it did not exceed the breadth of
  twelve  fingers; from duodcnus, consisting of twelve.
Dura Mater. The outermost membrane of the brain;  called dura,
  because it is much  harder than the other membranes, and mater,
  from the idea of the ancients  that it was the  source of all the
  other membranes.

                              E.
Embryo. The child in the womb is so called before the fifth month,
   after which it is termed fee! us; from tftfyvai to bud forth.
Enarthrosis. An articulation of bones; from ti in, and «g^«» a joint
   or articulation.
Enteric. Belonging to the intestines; from emgor an entrail or in-
  testine.
Epidermis. The scarf or outermost skin; from tm upon, and h%fnf
  the skin.
Epididymis. The small oblong body which lies above the testicles;
  from rri upon, and 2;5y«o« a testicle.
Epigastric. The superior part of the  abdomen; from ivt upon,, and
  y«s-«g the stomach.
Epiglottis. A cartilage of  the larynx so called; from nrt upon, and
  yXtirlig the aperture of the larynx,being situated upon the glottis.
Epiphysis. A portion of bone growing upon another bone, but sepa-
  rated from it by a cartilage: from ixt upon, and Qva to grow. 
412                    Glossary.
Epiploon. The membranous viscus of the abdomen, which covers
  the intestines, and hangs to the bottom of the stomach; from «jtc
  wA«» to swim  upon.
Ethmoid. From  efyto? a sieve, and «3ej resemblance; being perforated
  like a sieve.

                             F.
Fascia. An expansion, enclosing other parts, like a band; ivomfas-
  cis a bundle.
Falciform. Shaped like a scythe; fromfaLv a scythe.
Fasciculus. A little bundle, dim. of fascia a bundle.
Fauces. The plural of/awx,the top of the throat.

                             G.
Ganglion. Tx[yXui,  a knot in the course of a nerve.
Gastrocnemius. The muscle which forms the thick of the leg; from
  y«?«5 a belly,  and Kv^n the leg.
GcnTo. Names compounded with this word belong to muscles which
  are attached to the  chin, as genio-glossus—genio-hyoideus, &c;
  from yimo* the chin.
Ginglymui. An articulation; from yjfyAv^os a hinge.
Glenoid cavity. From  yA^, a cavity, and ui»s resemblance.
Glosso. Names  compounded  with this word  belong to muscles
  which are  attached to the tongue; as glosso-pharyngeus__glosso-
  staphilinus, Sec;  from yxua-ra the tongue.
Glottis. Ihe  superior  opening of the larynx at the bottom of the
  tongue; from yXu-flx the tongue.
Gluteus. The name of a muscle; from yA«T«« the buttocks.
Ga/nphosis. roppuTts, a species of immovable connexion of bones;
  bom yoptpof a nail,  because one bone is  fixed in another bone
  like a nail  in a board.

                             H.
Helix. The outward circle of the ear; from uxw to turn about.
Hepar. The  liver 'h^, an abdominal viscus.
Hyaloid. From Uxo* glass, and s*3«5 likeness; the capsule of the vi-
  treous humour of the eye is  so called, from its transparent and
  glassy appearance.
Hymen. The membrane situated at  the entrance of the virgin va-
  gina; from 'rpnt Hymen, the god of marriage.
Hyoides. A bone of the tongue, so called from its resemblance  to
  the Greek v, from v, and ud»( resemblance. 
                           Glossary.                     413

 Hypochondrtum. That part of the body which>lies under the carti-
   lages of the spurious ribs; from lire under, and x»vdg«$ a cartilage.
 Hypogastric. The lower region of the fore part of the abdomen;
   from viro under, and y«?jgg the stomach.

                                I.
 Ileon. A portion of the small intestines;  from ttXtu to turn; being
   always convoluted.
 Ischium. The part of the os innominatum upon which we sit; from
   iv-fcva to sustain.
                                L.
 Lacuna. The excretory duct of the glands of the urethra and vagi-
    na; from lacus a channel.
  Lambdoidal suture. So called because it is shaped like the letter a,
    from A, and ttHos resemblance.
  Larynx. The superior'part of the windpipe; A«gt/y| the larynx.

                                M.
  Masseter. A muscle of the face, which assists in the action of chew-
    ing; pxc-traoftxt to chew.
  Mastoid. From ftxm a breast, and e/Se? likeness; shaped like a nip.
    pie or breast.
  Mediastinum. The production of the pleura, which divides the tho-
    rax intotwo cavities; from medium the middle,quad in medio stare.
  Mesentery.  The membranes  to which the  intestines are attached;
    from fitirof the middle, and tvrt^»» an intestine, because it is in the
    middle of the intestines.
  Mesocolon. That part of the mesentery in the  middle  of the colon;
    from jttee-ef the middle, and  xoA«» the colon.
r  Metacarpus. That part of the hand between the carpus and fingers;
     from fcfrx after, anil xxpx-os the wrist.
  Metatarsus. That part of the foot between the  tarsus and toes; from
    ftET« after, and rx^a-og the tarsus.
  Mylo. Namcscompounded with this word belong to muscles which
    are attached near the grinders,  as mylo-hyoideus, Sec; from pvX*
     a grinder tooth.

   Odontoid. Tooth-like; from o3*« a tooth, and s<3«? resemblance.
  CEsophagus. The canal leading from the  pharynx to  the  stomach;
     from on*  to carry, and Qxyu to  eat; be-cause it carries the food
     into the stomach. 
414
Glossary.
 Olecranon. The elbow^ or head of the ulna; from uXtin the cubit, and
   Kg«wthe head.
 Omentum. An abdominal viscus; so called from omen a guess; be-
   cause the soothsayers prophesied from the inspection of this part.
 Omo. Names compounded with this word belong to muscles which
   are attached to the  scapula, as omo-hyoideus, Sec, from apos the
   shoulder.
 Omoplata. The scapula or shoulder blade; from  apog the shoulder,
   and irXxtvg broad.
 Osteology. The doctrine of the bones; from ofeon a bone, and Aey«s
   a discourse.

                              P.
 Pancreas. A viscus of the abdomen;  so called from its fleshy  con-
   sistence; from tx* all, and xgias flesh.
 Parenchyma. The substance of some  of  the*  viscera was so called,
   from  5r*£iyxt/« to pour through.
 Parotid Gland; from irx^x near, and ovs the ear;  because it is situ-
   ated near the ear.
 Pelvis. A  bony cavity shaped like a bason; from wtXvt a bason.
 Pericardium. The membrane which surrounds the heart; from nip
   around, and xa$tx the heart.
 Pericranium. The membrane which covers the bones of the skull;
   from  5T£§< around, and x^xuov the cranium or head.
 Periosteum. The membrane which surrounds the bones; from jrep
   around, and a«-eov a bone.
 Peristaltic motion of the intestines; from 5reg»«-«AA«, to  contract.
 Peritoneum. The membrane lining the abdomen, and covering its
   viscera; from jre^nuvu to extend around.
 Phalanx. The bones of the fingers and toes are  called phalanxes,
   from their regular situation, like a <p«A*yg, or arrangement of
   soldiers.
 Pharynx.  A membranous bag at the end of the mouth; «?«» <pfgs«r,
   because it conveys the food into the stomach.
 Phrenic or diaphragmatic nerve.  *gm? the diaphragm; from £p»v the
   mind; because the ancients supposed it to be the seat of the mind.
 Pia Mater. The innermost membrane of the brain, so called because
   it embraces the brain as a careful mother folds her child.
Pleura.  The membrane lining the thorax; irXtv^x the  side.
 Plexus. A  kind of net-work of vessels or nerves; from plecto to
   weave together. 
Glossary.                     415
Psoas. A muscle so called; from -^ex the loin, being situated in the
  loins.
Pterygoid process. From *\tey% a pen or wing, and uhs likeness; so
  called from its likeness to a pen or wing.
Pylorus. The lower  orifice of the  stomach, which opens into the
  intestines; from wuAe» to guard an entrance, because it guards as
  it were  the entrance of the bowels.

                              R.
Raphe. A suture; from fxifta to sew.
Renes. The  kidneys, «!» tk p£<v, because through them the urine
  flows.
Retina. The net-like expansion of the optic  nerve,  on  the inner
  surface of the eye; from rete a net.
Rhomboides. A muscle so called from its shape; from popZot a geo-
  metrical figure, whose sides are  equal but not right-angled, and
  e*Se«a likeness.
Rotiila. The knee-pan; a dim. of rota a wheel, from its shape.

                              S.
Sacrum. A bone so called; from  sacer sacred, because it was once
  offered  in sacrifices.
Salvatella. A vein of the foot, so called because it was thought that
  opening it preserved health, and  cured melancholy; from salvo
  to preserve.
Sanguis. The blood; xno rv rxetv yvix,because it preserves the body.
Sartorius.  A muscle so called, because tailors cross their legs with
  it; from sartor  a tailor.
Scapha. The  depression  of  the  outer ear before  the  anti-helix;
  from o-xxtpn a little boat or skiff".
Scaphoides.  A bone of the carpus, so called from its resemblance to
  a skiff; from orxxQn a skiff, and «3«s  likeness.
Sclerotic. A term applied to the outermost or hardest membrane of
  the eye;  from a-xXti^oa to make hard.
Sesamoid bones. From a-no-xut, a grain, and wSas likeness; from their
  resemblance to the semen sesami.
Sigmoid. Parts are so called from  their resemblance to the letter 2;
  from 2, the letter  Sigma, and «<3««  likeness.
Sphenoid. From <np»»awedge,and «<**«« likeness; shaped like a wedge.
Sphincter. The name of several muscles whose office  is to shut up
  the aperture around which theyare placed; from <r<p<yy« to shut up.
Splanchnic. From rirXxy;c<>o, an entrail. 
 416                     Glossary.

 Symphysis. A connexion of bones; from rvpfw to grow together.
 Synarthrosis. A connexion of bones; from avt with, and xeifo* a joint.
 Synchondrosis.  A species of union of bones by means of cartilage;
   from <rvi with, and £«»*?pe? a cartilage.
 SynneurDsis.  A  species of connexion of bones by means of mem-
   brane; from o-t»» with, and ttv^n a nerve; because membranes,
   ligaments, and  tendons,  were by  the ancients  considered as
   nerves.
 Syssarcosis. A species of connexion of bones by means of muscle;
   from o-unwith, and &*& flesh.
 Systole. The contractile motion of the heart and arteries; from <rw
   tiAA* to contract.
                              T.
 Tendon. From ruw to extend.
 Thorax. ©4/g«|. The breast or chest.
 Thyroid. From 0«gse? a shield,and e«Sa?  likeness; shaped like a shield.
 Trachea. The windpipe, so called from its roughness; from r^x^vt
   rough.
 Trochanter. A process of the thigh-bone, so called from rge^aj a
   wheel.
                              U.
 Ulna. A name for the cubit; from uXevy, the cubit.
 Ureter. The canal which conveys the urine from the  kidney to the
   bladder; from wg«» urine.
 Urethra. The passage through  which the  urine passes from the
   bladder; from »§»» the urine.
 Uvea. The posterior lamina of the iris,  so called because in many
   animals it is of the colour of  unripe grapes; from uva an unripe
   grape.
 Uvula. The conicle substance  which hangs down from the middle
   of the soft palate: so called from its resemblance to a grape. A
   dim. of uva a grape.
                              V.
 Valves. From valvx folding doorS.
 Vertebrx. The bones of the spine are so called;  from verto to turn.

                              X.
Xiphoid. So called from the  resemblance to a sword; from {<?« a
   sword, and e/3e« likeness.
                              Z.
Zygoma. The cavity under the zygomatic process of the temporal
   bones; from t^yog a yoke. 
INDEX.
A.
Abdomen.....
Abernethy, Mr. statement by him in the London Phi-
                 losophical Transactions
               case of termination of the vena porta-
               rum in the vena cava below the liver
               description by,  of  the  menseteric
                 gland of the whale
Absorbent vessels       -
               of the lower extremities
               of the head and  neck
               of the abdomen and thorax  -
               of the arm and upper part of the trunk
Acetabulum     -
Accessory nerve of Willis   -      -      -      -
Acini of the liver       -
Adhesion of the lungs to the thorax -      -      -
Adipose artery   -
        membrane   -      -      -      -      -
Adjustment of the center of gravity
Alphabetical arrangement of the muscles
Alveolar artery  -      -       -      -
Anastomotic artery  -      -      -      -      -
Andre, M. St.
Animal motion, question respecting -
Aorta    ------
    table  of  the, exhibiting the distribution of its
      branches      -      -      -      -      -
Appearance of the caecum and colon
Appendix of the diaphragm -      -      -      -
Aqueducts of the ear    -      - .     -
Aqueous humour    -
   Vol. II.                 3G
Vol.1.
Page
98
387
395
235
398
160
202
381
357
Vol.11.
 Page
   81
 58

135

364
361
366
382
371
383

332
129
 72
271
239
283
229
288
115 
418
INDEX.
                                                   Vol. I. Vol.11.
                                                   Page   Page
Arbor vitas      -       -       -      -             321
Arm, bones of the    -       -      -       -       -   109
     nerves of the       -                                    338
Arrangement of the jejunum and ileon      -       -           111
Arteries, general account of their distribution    -              227
Articulations, general account of    -                 263
Astragalus      -       -       -      -       -      142
          articulation of the        -       -       -   284
Auditory nerve  -----      380
Auricular artery     -----           236
Axillary artery   -       -       -      -       -              252
         vein.....           299
Azygos, vena    -----              292

                           B.
Baillie, Dr.......                 76
Ball of the eye   -----      337
Barclay, Dr. ------           252
Basilar artery    -----              249
Basilic vein   ------           299
Basis of the cranium                                  59
           brain     -       -      -       -       -   321
Baynham, Dr. of Virginia, his method of injecting the
  rete mucosum -----      394
Bell, C.      -       -       -      -       -       -   359
Bell, John, observation of       ...              136
Berlin, royal academy of sciences of -       -       -   400
Berzelius, professor of chemistry at Stockholm, his
  experiment on secretion       -                            405
Bichat, M. opinion embraced by, respecting the ex-
             tent of the retina     -       -       -   351
           of the pores of the cuticle    -       -      401
           doubts of, the existence of the rete muco-
             sum in the tongue   -                         21
           his solution of a problem    -       -               73
           doubts  of,  respecting the muscularity  of
             arteries       ....           220
           on the structure of arteries   -       -              220
Biliary duct ----..           135
Biliary and pancreatic ducts, orifices of  -       -              111
Bile -------           137
Bladder, gall    -----              135 
INDEX.
419
Bladder, urinary -Blood - - . . . colouring matter of the Bloodvessels in general - . of the tongue ... of the abdomen	-	Vol.T. Page	Vol. U. Page 157 394 396 215 23 86
Boerhaave, K, experiments of Bones, structure of	-	1	386
formation of -	.	5	
terms used in the description of -Bostock, Dr. -	-	6	70
his assertion respecting the blood Boyer, M. -Brachial plexus of nerves	-		394 162 337
construction of the -	-		338
Brande, Mr. on the serum of the blood - '	-		394
his chemical researches respecting the blood -			399
Brain, basis of -	-	321	
commissures of	-	317	
, middle artery of -	-		246
nerves of	-	321	
British anatomists on the spleen -	-		147
Brodie on the source of motion in the heart -	-		80
Bronchiae, black glands on	-		63
Bronchial artery - - - -Bucquet, M. Buisson, M. -			262 398 331
Bursa? mucosa? - - - -	265	,292	
C.			
Caecum -	-		115
position of Camper -Canals, semicircular -	-	378	126 211
Capsular arteries -veins - - - -	*		271 303
Cardiac plexus -	-		355
Carlysle, Dr. -Carotid arteries -	.	155	229
Carpus - - - - -Cauda equina -	-	119 32*	
 
420
INDEX.
		Vol. 1.	Vol.11.
		Page	Page
Cavallo, Tiberius -			397
Cavities of the nose - - - -	-	53	
Cavity of the cranium - - - -		^ 56	
tympanum	-	366	
Cellular membrane - - - -		384	
Cerebellum - - -	-	320	
Cerebrum -		310	
Cephalic vein -	-		298
Change of colour in negroes, instance of-		395	
Changes of the rete mucosum in white persons	-	396	
Change of position in the stomach			96
Choctaw Indians, custom of -	-	62	
Chorda Tympani - - - - -		373	
Choroid coat - - - - -	-	341	
Ciliary ligament - - - - -		343	
processes - - - -	-	348	
Circulation in the placenta, object of the			213
Circumflex artery of the os ilium	-		280
vein - - - - -			305
Clavicle _...--	-	102	
Coat of the liver - - - - -			129
Cochlea - - - - -	-	376	
Colon, structure of			117
valve of the - - - -	-		118
Cooper, Mr. Astley -			83
Cornea -	-	339	
Coronary veins -	-		290
Corpora albicantia of Willis -		S23	
Corpora cavernosa - - - -	■		180
qells of the ...			181
lutea - - - -	-		202
Corpus spongiosum - - - -			182
structure of	-		183
Corpuscula Arantii -			55
Cr-ssamentum -	-		395
Cremaster muscle -			169
Cricoid cartilage -	-		31
Cruikshank, Mr. Win. his opinion respecting the ves-			
sels between the rete mucosum	ind		
cutis ...	392	, 394	
his experiments favourable to the idea			
of the motions of the heart being	in-		
dependent of the brain	-		78
 
INDEX.
421
                                                  Vol. I.  Vol.11.
                                                   Page    Page
Cruikshank, Mr. Wm. his ideas relative to the origin
               of the lacteals   -      -      -         106,363
             his description of the appearance of the
               absorbents of the kidney     -      -    '      371
             His  injection of  the absorbents of the
               pancreas         ...             377
             his demonstration of those of the lungs           379
Crural nerve        -                                      345
Crystalline lens   -----     355
Cubital nerves       -      -       -       -      -          334
Currie, Dr. (of Liverpool)       -                           385
Cuticle      ---...  398
Cuticle, pores of  -      -       -       -       -     399
        peculiar permeability  of     -       -      -  401
        separation of the -  •    -       -       -     403
        chemical qualities of the     -                404
Cuvier, M. his opinion respecting the vascular  con-
            volutions  of the  corpus spongiosum  of
            the horse      -       -       -      -          191

                              D.
Daingerfield, Dr.  his experiments       -      -             385
Delile,  M. his memoir on the organs of absorption  in
           mammiferous animals    ...          387
Dcsault, M. his ideas  respecting the  structure of the
           spleen        -                                   145
        his experiment respecting the frontal sinus             13
Diaphragm  ------  202
           nerves of the  -       -       -       -             336
Digital  arteries      -      -        -       -       -          26°
Dorsal nerves    -----             342
Dorsey, Dr. John  S.  -      -        -       -       -           7I
Duct, thoracic    -----             377
      hepatic       -      -        -       -       -          '32
      cystic      -----             13a
Ductus  venosus      -      -        -       -       -          212
Duodenum       -----             302
Dupuytren,  M. inference  from  his  statement in a
               volume of the  proceedings of the Na-
               tional Institute, respecting the nerves
               of the lungs -        -       -       -
Dura mater      ...      -       -     205
72 
422
INDEX.
Vol.l.	Vol. 11.
Page	Pago
- 361	
370	
-	70
274	
-	271
	303
- 398	
	166
-	279
	306
.	30
368	
-	281
	279
-	305
51	
. 331	
337	
- 352	
353	
                              E.
Ear  ------
   bones of the   -       -      -       -
Ellis on respiration   -      -       -      -
Elbow, articulation of the
Emulgent arteries   -
          veins   -       -      -       -
Epidermis   -       -      -       -      -
Epididymis      -
Epigastric artery    -      -  -     -
          vein   -
Epiglottis    -       -      -       -      -
Eustachian tube   -       -      -       -
External pudic arteries      -
External iliac arteries    -      -   *   -
         iliac veins  -      -       -      -
Eye, description of the orbit of the
     parts auxiliary  to the  -
     ball of the   -       -      -       -
     humours of the        -
     dissection of the     -
     effect of the solution of nitrate of silver on  the
        hyaloid coat of the   -       -      -       -  360

                               F.
Face      ------       32
Facial  artery         -      -       -      -       -          215
Fauces, isthmus of the  .  -       -       -       -               29
Fallopian tubes, structure of the     -                         200
Falconer, Mr. on the spleen      -                            147
Falx......307
Femoral artery   -----              280
         vein        -----          306
Foetus, head  of   -       -       -       -       -       63
        thorax of           -       -       -           65
        trunk of -       -       -      -       -      101
        extremities of       -       -       -        -   152
Fibula    -      -       -       -      -              136
Fimbriae     ------          201
Fingers  ------      129
        articulation  of the   -       .       -        -   277
Foot      ------      ui 
INDEX.
42S
                                                  ▼oil.  VoI.IL
 Fontana, Abbe      -      .      .                Page    Pagc
                .u                       "      "          7«
             on the structure of the nerves     -      150
             on the colour of the blood     -      -         39fi
 Foramen caecum  -      -       _      .      .      22
         lacerum    -      -      .      .      -   60
         ovale    -      -       -      -      .      55
         thyroideum       -      -      .      -   98
 Forearm  -      -      -       _      .      _      113
         interosseous ligament of the       -      -  286
 Fornix   -      -              .      .      .315
 Fossa ovalis        _      -      .      _      -   74
 Fourcroy, M.                                             ,.5
 French anatomists,  their peculiar opinions  respect-
   ing the course of the blood in the foetus   -                 73
 Fyfe, Mr. on the villi    -                                 ,07

                              G.
 Gall, Dr.     -      -      .      .      .      -  326
 Ganglions       -      -       .      .      .            -jo
 Gastric liquor       -                                     l00
 Gavard, M. proposition of        -      -      .            U4
 Generation, female organs of       -                       192
            male organs of       ...            155
 Glands, inguinal     -       -       -      -      -         35s
 Glands on the bronchiae  -                                  63
       of the mesentery     -      -       -      .         115
       of the neck       ....             332
 Glandulae Buccales  -                                       15
          Brunneri      -                                  104
          Peyeri     -                                      104
          Molares       -       -      -'      -             246
         Renales    -                                      150
 Gluteal artery   -----             277
 Goodwin, Dr. his explanation of the effects of venous
             blood on the heart     - »     -       -           73
Graff" De, his successful investigation of the testicle            174
Grew, Dr.       -                                  400

                             H.
Haighton, Mr. a dissection of the ear recorded by   -   383
              essay of  -                                   3t»
Haller, M. on muscular fibres       -       -       -   155
           remarkable sentiment  of                          42 
424
INDEX.
                                                  Vol. I.
                                                   Page
Haller, M. inclined to the opinion of Ruysch on the
             spleen        -       -       -       -
         a cavity in the glandulae renales frequently
            found by   -
         his publication in the  Philosophical Trans-
             actions of London      -       -       -
         on the testicles of the foetus
         his great attention to the arterial system
         his observations on the absorbent vessels
Hand......119
Hatchet, Mr. Charles    .      -       -      -
Heart, description of the    -
Hepatic artery   -      -      -       -      -
       veins       -
Hewson, Mr. William, on the  villi
                 his opinion  respecting the spleen
                 on serum -       -       -       -
                 on the crassamentum  -
                 on the colour of the blood
                 on the structure of glands
Hewson, Dr. T. T. his experiments on the blood
Home, Mr. Croonian lecture of -
           his assertion  respecting the membrana
              tympani     -
           confirmation of the account of the vesicles
              in the spleen     -
           his questions relative to the blood
Hottentots, female, peculiarity of the
Humboldt, M. on the experiments of Legallois
Humeral artery  -     .  -
Hungarians, peculiarity of the      ...
Hunter, Dr. William     -              -       -     387
             opinion of, on the villi -
             his opinion respecting  the  structure of
               glands   -      -       -       -
             belief respecting a part in glands not in-
               jected in his preparations
             his ideas of fluids which appear in vari-
               ous cavities of the body  -
Hunter, Mr. John    -       -      -      -       .
           his opinion respecting the vascular struc-
             ture of the corpus spongiosum urethrae
160
-  368
Vol.11.
 Page

  146

  151

  174
  211
  251
  362

  395
   50
  266
  301
  106
  147
  394
  396
  397
  402
  396
   148
   405
   208
    79
   255
   211
    71
    106

    403

    403

    404
100,177

    191 
INDEX.
425
                                                   Vol.1. Vol.11.

Hunter, Mr/John, fact established by experiments of         ^
           on the structure of arteries      -       -          219
           on the colour of the blood    -       -            397
Hypogastric artery  -
            vein  -
                            I—J.
Iliac arteries     -
     veins  -
L.	
Labia externa ....	-
Labyrinth -	374
contents of the ...	- 379
functions of the different parts of	383
Laennec, M. -	-
Lachrymal gland - - - -	334
sac . . .	- 335
Vol. II. 3H	
274
304
273
                                                            304
 Injected preparations, examination of           -             261
 Instances of peculiar arrangement of veins  -      -          307
 Intercostal arteries       -                                   263
          veins     -                                       2g2
 Interosseal artery        -                                   259
 Internal basis of the cranium        -       -      -   56
 Intestines        -                                          103
         division of -       -      -       .      .          108
 Iris      -               -              -      -     344
 Ischiatic artery      -       -      .      -      .          277
 Jejunum and ileon       -       -       -      -             111
 Jones, Dr.   ------          220
 Jugular veins, internal    -                                   395
              external     -                                397
 Jussieu, M. account by,  of a female born without a
   tongue        -----             27

                              K.
 Kidneys     ...              .      .          152
        cortical and tubular portions of the      -             155
        nerves, lymphatics, and coat of the  -      -          156
        absorbents of the         ...            371
Klapp, Dr.   -----      -         385
Knee, articulation of the -       -       -      -     280
193
129 
426                      INDEX.
Vol.1.  Vol. II.
 Page    Page
         372
          SI
Lacteals  -      -      -      -
Larynx      -
Legallois, M. experiments of, on the source of the
               motion of the heart -       -       -
Lieberkuhn, M.  -
Lieutaud, M.
t-                            ...      286
Ligaments       -
Liver        -
     absorbents of the  -
                                                           273
                                                           304
                                                           343
                                                           344
                                                            64
                                                            66
106
162

125
Lumbar arteries     -
        veins    -      -      -      -
        nerves      -
        plexus   -      -      -      -
Lungs,      -
      structure of
      absorbents of -
Lymphatics in the spermatic cord       -                     *69
           of the uterus    -       -       -       -           204

                             M.
Magendie, M. experiments of, on the  organs of ab-
                sorption in mammiferous animals             3&7
Malformation, cases of       -
Malpighi, M. on the structure of the spleen     -             144
             on the structure of glands    -      -          402
Mammary artery
Marcet, Dr.
Mascagni, M. on the villi
             on the absorbents of the kidney      -          371
             assertion of, in his  great work on the
                absorbent  system      -       -             403
              his ideas respecting the structuije  of
                glands     .       -      -      -
 Mastoid cells    -      -       -      -     ■  -     369
 Maxilla inferior     -       -      -      ♦      -    42
 Maxillary arteries       "       "      "       ",            236
          nerves    -                                      319
 Meatus Auditorius Externus    -      -       -      364
                   Internus        -      -       -   379
 Meckle> Professor, his opinion  respecting the outlets
                    of perspiration      -       -      4C0
                  on the nerves of the face        -          327
218
 71
107
403 
INDEX.
427
Mediastinum     -
Median nerve  *--.-.
       vein      -----
Meibomus, glands of        -
Membrane, adipose      -
            Schneiderian    -
                       extent of
                       distribution of
Membrana tympani      ....
                  observations on the
Menghini, Vincentius, his experiments tending to es-
  tablishment the opinion, that the colour of the blood
  depends upon iron     -       -      -      .
Mesentery   ------
          construction  of
          root of                         -       -
Mesenteric  artery       -
           vein     -      -      .      .       .
Metacarpus      -       -       •      -      -
Metatarsus   ------
Middle,haemorrhoidal vein
       sacral vein   -      -      -      -       -
Monro, Dr. on the Bursae Mucosae
            on the iris       -
Monro, Dr. opinion of, respecting  the  extent of the
             retina  -      -      -      -       -
           his opinion respecting the villi
           observation of, on the epididymis
Morgagni, M. ventricle of
Motion, muscular, phenomena of   -
        of the skeleton   -      -      -       -
Mouth      ------
       internal surface of the    -      -       -
Mucus of the nose   -
       of the bladder     -
Mussey, Dr.        -
Muscles, alphabetical arrangement of
Vol. I.	Vol. 11.
Page	Page
	45
	339
	299
334	
395	
5	
9	
10	
367	
373	
110
111
113
124
148
265
346

351
158
159
598
270
302
276
304
106
174
 J4
 14
 15
 12
161
385
255
N.
Nails   -
Neck, arteries of the
      absorbents of the
405
251
383 
425
INDEX.
Neck, muscles of the
Nerves, general account of
Nichols, Dr. F.   -
Nose
     cavities of the
     nerves of
     sinuses of   -
Vol. I.
 Page
 210
53
Vol. II
 Page

  319
  147
    1
    4
    6
   12
                             O.
Obturator artery                -
Occipital artery     -
Oesophagus      -
Olfactory nerve     -
Omentum, origin and arrangement of
          varieties in  the appearance of
Ophthalmic artery
           nerve   -
Ovaries   -
Os frontis    -
Ossa parietalia   -
Ossatemporum
Os occipitis      ...
Os ethmoides       -
Os sphenoides   -       -       -
Ossa maxillaria superiora
Ossa nasi -      -
Ossa unguis -      -       -      -
Ossa malarum   -
Ossa palati         -
Ossa spongiosa  -
Os hyoides
Os sacrum
Os coccygis
Os ilium -      -       -       -
Os ischium    -
Os pubis
Os humeri  -      -       -      -
Os femoris
Os calcis    .      -       -      -
Os naviculare
Os cuboides
Os cuneiforrae
    14
    16
    18
    21
33,409
    27
-   32
    36
-   37
    37
-   38
    41
-   50
    79
-   81
    94
-   95
    97
-  109
   131
-  143
   145
-  145
   146
276
235
 93
315
123
124
243
318
201 
INDEX.
       429
Vol.I.  Vol. II
 Page   Page
139
140
140
 21
328
 25
                               P.
 Palpebrae        -                                  332
 Pancreas    ----._
 Pancreatic duct  -
 Pancreas enlarged, symptoms of    -
 Papillae of the tongue    -
 Par Vagum  ----._
 Parotid gland    -----
 Patella      -      -       -       .       _       -   139
 Pears, Mr. C. account by, of a woman in whom the
     ovaria were deficient        ...             208
 Peculiarity of the liver       -                               l35
 Pelvis    ------       93
      ligaments of the        -       -       -       .   289
      absorbents of the   -       -       -       .             371
 Perforating arteries -                                      282
 Pericardium     -                                          49
 Peritoneum  --.---.           88
 Periosteum      -                                    2
 Peroneal artery     -       -       -       -       .          286
         nerve   -----             349
 Pharyngeal artery,  inferior   -                               234
 Pharynx, structure  of the        ...              38
 Phrenic artery      -                                      265
         vein     ---..             301
 Physick, Dr. his opinion respecting incisions of the
     cornea  ------   340
 Pia mater        -----      306
 Pineal gland        -       -       -       -       -   318
 Pleura, arrangement of the       -       -       -              45
 Plexuses of nerves   -       -       -       -       -          312
 Plexus choroides        -       -       -       -      316
 Pomum Adami      -----           32
 Popliteal artery   -----             283
 Pores of the cutis vera       -       -       -       -   391
 Portarum vena   -       -       -      -      -             131
 Portio Dura  ------          325
Posterior iliac artery     -      .      -      -             277
Poupart's ligament, method of preparing it for  exa-
           mination        -       -       -       -   192
Priestley, Dr.     -----              70
Primitive iliac arteries      -       -              -          27:> 
430
INDEX.
                                                   Vol.1.  Vol.U.
                                                   Page   Page
Primitive iliac veins      -                                   304
Provencal, Dr. J. M.        -                                 72
Pudic artery     -----             278
Pulmonary arteries and veins       ...        60,308
          plexus        ....             332
Puncta Lachrymalis         ...      -  353
Pylorus  ------             101

                             Q-
Questions, respecting perspiration   -                400
the structure of the spleen		148
Questions of Mr. Home - - ,	■	405
R. Radial artery - -		257
nerve -	-	341
Radius ------	116	
Reticular membrane -	- 387	
Reaumur, M.		100
Rectum, position and structure of -	-	120
Renal arteries - - - - -		271
Reproduction of nerves -	-	314
Rete mucosum - - - - -	393	
Retina -	- 350	
Ribs......	83	
Ridley, circular sinus of - - -	- 309	
Rima glottidis - - - - -		34
Rivinus, professor, erroneous opinion of	- 368	
Rolland, M. - - - - -		27
Rousseau, Dr. -	-	385"
Rush, Dr. James -		124
Ruysch, M. -	- 343	
preparation of		15
on the structure of the spleen	.	144
his opinion oh the structure of glands		402
                              S.
Sabatier, M. idea of, respecting the bloodvessels and
              the colour of muscles    -      -      156
            theory of, relative to  the foetal  circula-
              tion  -----            74
            observation of, on the stomach     -              102 
                           INDEX.                       4G1

                                                   Vol.1.  Vol. II.
                                                   Page   Page
Sabatier, M. supposition of> respecting the rectum   •          119
Sacral artery        -      -      -      . -       -          224
Saliva    ---.--              26
Salivary glands      -----           2*
Scapula  ------      104
        articulation of      -      -       -       -   271
Sciatic  nerve     -----             348
        plexus       -----          347
Serum       ------          394
Scheele, Mr.     -----              70
Schneider, Dr. Conrad      *■                                 5
Sheldon, Mr. John       ...       -             106
Shippen, Dr. J. G.   -      -       -      •       -         114
Sims, Dr.        -----      374
Skin, vicarious affections of the      -                407
Sone, De La, opinion of, on the spleen   -                    146
Soemmering, interesting discovery of      -       -  351
             idea of, respecting the papillae of the
                tongue   -       -       -      -             22
              opinion of, on the villi -      -       -         107
              statement  of, respecting injections  of
                absorbent vessels        -      -            364
 Smelling, function of        ...      -          11
 Spallanzani, Abbe       _       -       -      -             70
                 dissertation of            -      -         10°
 Spheno-Palatine artery   -       -       -      -            239
 Spleen, general account of   -
        absorbents of
 Spinal  marrow      .       -       -                327
               arteries of the    -                    329
               veins of the  -                        333
 Spermatic arteries       .       -       -
           veins      -
 Splenic artery     -
 Stewart, Dr. J. Bradner
 Stiles,  Sir F. H. E.
Stomach, general view of the
          absorbents of   -
 Structure of ganglions
          of glands
 Subclavian arteries   -
            veins
 271
 303
 267
 385
,397
  95
 374
 307
 400
 247
 302 
432                     INDEX.
                                                 Vol.1.  Vol. It.
                                                 Page   Page
Superior mesenteric artery  -                               268
                  vein       -      -      -             302
Superior vena cava  -      -      -      -      -          **9'
Sympathetic nerve      -                                  351

                            T.
Tears       -     -      ...      -      -  335
Teeth   ------      45
Temporal artery    -----          240
Thebesius, a German Professor, assertion of    -              $8
Thigh......130
Thoracic duct   -----             377
Thorax      ------           41
Throat......              29
Thymus gland     -----           67
Thyroid artery, superior        -                           232
             inferior     -      .      -      -          248
Tongue   ------              18
Torre, Father de la -      -      -      -      -          397
Trachea  ------              62
Tunica Arachnoidea -      -      -      -      -  305
Tunica Conjunctiva     -                          333
Tunica Sclerotica    -----  338
Tunica Choroides       -      -      -       -     341
Tunica Hyaloidea    -----  353
               fluid in the           -       -     354
Tympanum, cavity of the   -      -      -      -  366
          foramina and protuberances of the   -     369

                             U.
Umbilical vessels   -             -      -      -          211
Ulna......114
UUiar artery        -----          259
      nerve      -----             340
Urine       ------          164
Uterine artery   -----             277
Uterus       ------           197
Valve of Eustachius     -                                   53
       Vieussens   -      -      -       -      -  321
Valvulae Tricuspides    -                                   53 
INDEX.
433
                                                 Vol.1.  Vol II.
                                                  Page    Page
Valvolae Mitrales        -                                    56
        Semilunares       -      -      -      N-           55
Vas Deferens    -                                         175
Vauquelin, M.                                              398
Vena azygos     -----             292
Vena cava, superior         -      -      -       -          291
           inferior      -                                  300
Vena Galeni        -       -      -      -       -   319
Vena portarum   -----             3q2
Venae vesicales     -----          304
Ventricles of the brain   -       -       -       -      313
Veins, particular distribution of                             289
Veins of the heart       -       -       -       -             290
Vertebrae, connexion of, with the head      -       -   266
           articulation of, with each other       -      267
Vertebrae, true      -       -       -       -       -    66
Vertebrae, false  -----       79
Vertebral artery    -----          249
           vein   -----             306
Vesalius, M. his method of examining the brain       317
 Vesication, causes of        -       -      -      -  402
 Vestibule       -----      376
 Vidius, professor, reputeddiscoverer of the pterygoid
            foramen -       -       -       -       -    31
 Vieussens, assertion of   -                                    58
 Vitreous humour   -       -       -      -      -  353

                              XV.
 Wells, Dr.                                                 3"
                                                            405
                                                             73
Wollaston, Mr.      -
Winslow         -
Wilson, James, Esq.        -       -       ■       -  197
Willis, accessory nerve of
Wrist, articulation of        -                        275
332
Vol. II.
3 I 
ERRATA.
                                 VOLUME L.
Fagc 70....8th line from below, for cervical read vertebral.
    178....1st line, for palati read palate.
    191....7th line, for their facia read thin facia.
    214.. ..10th from below, (or frst vertebra of the neck read vertebra of the neck.
    267...l4th line, for bones of the condyles read bases of the condyles.
    323...10th line, for Pons Variolii read Pons Varolii.
    345....5th line, (orplain read plane.
    340, 354, 355,  356, for lamen read lamina—for lamina read laminte.
    375 ...3d line from below, (or solid read hard.
    384....4th line, for these  read  tliem.
    394....10th line from below, for as injection read as an injection.
    407.... (title) for vicarious connexion read vicarious affections of the skin,

                                 VOLUME n
Page 94....19th line, for found read formed. 
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ANATOMICAL  PLATES
FROM
THE   ENCYCLOPEDIA.
  EXPLANATION OF THE  PLATES OF OSTEOLOGY.

                        Plate XIX.
         Fig. 1. A Front-view of the Male Skeleton.
  A, The os frontis. B, The os parietale. C, The coronal suture.
D, The squamous part of the  temporal bones. E, The squamous
suture.  F, The  zygoma.  G, The mastoid process. H, The tempo-
ral process of the sphenoid bone. I, The orbit. K, The os nialae.
L, The os maxillare superius. M, Its nasal process.  N, The ossa
nasi. O, The os unguis.  P, The  maxilla inferior. Q, The teeth,
which are sixteen in number in  each jaw. R, The seven cervical
vertebrae, with their intermediate cartilages. S, Their transverse
processes. T, The twelve dorsal  vertebra;, with their intermediate
cartilages.  U, The  five   lumbar vertebrae. V, Their transverse
processes. W, The upper part  of  the os sacrum. X, Its lateral
parts. The holes seen on its fore part are the passages of the un-
dermost 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,  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 seventh 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 car-
tilage ensilormis. s, The clavicle, t, The internal surface  of the
scapula,  u, Its  acromion, v, Its coracoid process,  w, Its cervix.
x, The  glenoid cavitv. y, The os humeri, z, Its head, which is
connected to the glenoid  cavity.  1, Its external tubercle. 2, Its in-
ternal tubercle.  3, The groove for lodging the long head  of the
biceps  muscle  of the arm. 4, The internal 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, n,
                             A 
2           Explanation of the Plates of Osteology.
18, The carpus; composed of os naviculare, os lunare, os cunei-
form e, os pisiforme, os trapezium, os trapezoides, os magnum, os
unciforme.  19, The  five bones of the metacarpus- *0, 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 trochan-
ter 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. 3 , Its spine. 34, The malleolus internus  35, The
fibula. 36, Its  head. 37, The  malleolus externus.  The tarsus is
composed of, 38, The  astragalus; 39. The os calcis;  40, The os
naviculare; 41, Three ossa cuneiformia, and the os cuboides, which
is not seen in this figure. 42, The five bones of ihe  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  supeiciliary
ridge. D, The superciliary hole through which the frontal vessels
and nerves pass  EE,  The orbitar  processes F, The middle of
the transverse suture.  Ci, The upper part ol the orbit. H, The fo-
ramen opticum.  I, The foramen lacerum.  K, The inferior orbitar
fissure.  L, The os unguis. M, The ossa nasi. N, The os maxillare
superius. O, Its nasal  process.  P, The external orbiiar 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 spongiosum superius.  V, The os spongiosum
inferius. W, The edge of the alveoli, or  spongy sockets for  the
teeth. X, The maxilla inferior. Y, The passage for the inferior
maxillary vessels and nerves.

              Fig. 3. A Side-view of the Skull
  A, The os frontis.  B, The coronal suture. C, The  os parietale.
D, An arched ridge which gives origin  to the temporal muscle.
E, The squamous suture. F, The squamous part of the temporal
bone: and farther forwards, the temporal  process of the spheroid
bone. G, The  zygomatic process of the  temporal  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. (), The right
os nasi.  P, the  superior maxillary bone.  Q, Its  nasal process.
R, The two dentes incisores  S, The  dens caninus.  T,  The  two
small molares  U, The three large mnlares. 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 tem-
poral bone.

       Fig. 4. The posterior and right side of the Skull.
  A,The os  frontis. BB,  The ossa  parietalia. C, The sagittal
suture. D, The parietal hole, through which a small vein runs to 
 
 
Explanation of the Plates of Osteology.
3
the superior longitudinal sinus. E, The lambdoid suture. FF, Ossa
triquetra  G, The os occipitis. H, The squamous part of the tem-
poral bone. I, The mastoid process. K, Ihe zygoma. L, The os
mala.  M, The temporal part of the sphenoid bone. N, The supe-
rior maxillary bone and teeth.     ,

        Fig.  5. The  External Surface of the Os Frontis.
  A, The convex part. B, Part of the temporal fossa. C, The ex-
ternal angular process. D, The internal angular process.  E, The
nasal process. F, The superciliary arch.  G, The superciliary hole.
H, The orbitar plate.

        Fig  6.  The Internal Surface of the Os Frontis.
   AA, The serrated edge which assists to form the coronal suture.
B, The external angular process. C, The internal  angular pro-
cess. D, The nasal  process. E, The orbitar  plate. F,The cells
which correspond  with those of the ethmoid bone.  G, The passage
from the frontal sinus. II, The opening  which receives  the cri-
briform 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.
   AA, The ossa parietalia. B, The sagittal suture.  C, The lamb-
 doid suture. D, The 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 inferior. 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 oblique  processes.  S, The spinous process. 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 membrane.  W, The os coccygis.  a, the
 os "ilium. Y, Its spine or crest. Z, The "chiatic niche, a, The os
 ischium, b,  Its  tuberosity,  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. ., The scapula, k, I  •
 spine  1, Its acromion,  m, Its cervix, n, Its superior costa. o. Its
 posterior costa. p, Its inferior costa. q, The,  o.  humeri  r. The
 radius, s, The  ulna, t,  Its olecranon, u, All the bones of thcar-
 nus excepting  the os pisiforme, which is seen in Plate XI A. tig. i.
 TThefiie  iSnes ofPthe  metacarpus, w, The two bones of the
 thumb x, The three bones of each of the fingers, y, The two se-
  am" d bones at  the  root of the left thumb, z, The: os femor s^
  l! The trochanter major. 2, The trochanter minor. 3  The luiea
     iZ  a Thl internal condyle. 5, The external condyle.  6 6, The
 aspera. 4, The internal cormyie   ,            mallcoius internus.
 similunar cartilages.  7, Ine tmia. o,  *»* 
4          Explanation of the Plates of Osteology.
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 parietal 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 forma-
tion of the coronal suture. C, The inferior edge for the squamous
suture. D, The posterior edge for the lambdoid suture. E, A de-
pression made by the lateral sinus. FF, 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 process. C,  The zy-
gomatic process. D, The styloid process.  E, The petrosal  process.
F, The meatus auditorius externus. G, The glenoid cavity for the
articulation of the lower jaw  H, The foramen stylo-mastoideum
for the  portio dura of the seventh pair of nerves. I, Passages for
blood-vessels into the bone.  K, The 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 form-
ing the squamous suture. B, ihe mastoid process.  C, The styloid
process. D, The pars petrosa. E, The entry of the seventh pair,
or auditory nerve F, The fossa, which lodges a part of the lateral
sinus. G, The foramen mastoideum.

Fio. 6. The External Surface of the Osseous Circle, which  ter-
           minates 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 de-
lineated 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 matteua. B> The incus. C, The os orbiculare. D, The
stapes.

Fie. 9. The Malleus, with its Head,  Handle, and  Small Pro.-
                          cesses. 
          Explanation of the Plates of Osteology.          5

tio. 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 anduorius internus. B, The  vestibulum.  CCC, The semi-
circular canals.

        Fig. 14. An External View of the Labyrinth.
  A, The semicircular canals. B,  The fenestra ovalis which leads
into the vesiibulum. C, The fenestra rotunda  which opens  into
the cochlea. D, The different turns  of the cochlea.

     Fig. 15. The Internal Surface of the 06 Sphenoides.
  AA, The  temporal  processes  BB, The pterygoid processes.
CC, The spinous processes. DD,  The anterior clinoid processes.
E, The posterior clinoid process.  F, The anterior process  which
joins the ethmoid bone. G, The sella turcica for lodging the glan-
dula pituitaria. H, The foramen opticum  K, The foramen lace-
rum. L, The foramen rotundum.  M, The foramen ovale. N, The
foramen spinale.

     Fig. 16. The External Surface of the Os Sphenoides.
  AA, The  temporal  processes.  BB, The pterygoid processes.
CC, The spinous processes. D, The processus azygos. 1.,  The
small triangular processes which grow from the body of the bone.
FF, The orifices of the sphenoidal sinuses. G, The foramen lace-
rum H, The foramen  rotundum. I, The foramen ovale. K, The
foramen pterygoideum.

      Fig. 17. The External View of the Os Ethmoides.
  A, The nasal lamella. BB, The grooves between the nasal la-
mella and ossa spongiosa superiora CC, The  ossa spongiosa supe-
riora. DD, The sphenoidal cornua.  See Fig.  16. E.

       Fig. 18. The Internal View of the Os Ethmoides.
  A, The crista galli. B, The cribriform plate, with the different
passages of the olfactory nerves. CC, Some of the ethmoidal cells.
D. The right os  planum. EE, The sphenoidal cornua.

           Fig.  19. The right Sphenoidal Cornu.

           Fig. 20. The left Sphenoidal Cornu.

     Fig. 21. The External Surface of the Os Occipitis.
  A, The upper part of the bone.  B, The superior arched  ridge.
C. The inferior arched ridge. Under the arches are prints made 
6          Explanation of the Plates of Osteology.
by the muscles of the  neck. DD, The two condyloid  processes
which articulate the head with the spine. E, The cuneilorm pro-
cess. F. The foramen magnum through which  the spinal marrow
passes. GG, The posterior condyloid  foramina which transmit
veins into the lateral sinuses. HH, The foramina lingualia for the
passage of the nine pair of nerves.

      Fig. 22. The internal Surface of the Os Occipitis.
  AA, the two sides which assist to form the  lambdoul suture.
B> The point of the cuneiform process, where it joins the sphenoid
bone. CC, The prints made by the posterior lobes  of  the brain.
DO, Prints made by the h)bes of the cerebellum. E, The  cruci-
form ridge for the attachment of the processes of ihe dura mater.
F, The course  of  the  superior longitudinal  sinuses.   GG,  The
course «>f the two lateral sinuses. H, The  foramen magnum. 11,
The posterior condyloid toramina.

                        Plate XXI.
            Fig  1. A  Side-View of the Skeleton.
  AA, The ossa parietalia. B, The sagittal  suiure.  C, The os
occipitis. DD, The lambdoid suture.  E,  The  squamous part of
the temporal bone.  F, The mastoid process. G, Ihe meatus au-
ditorius externus.  H, The os frontis. I, The os malae. K, The
os maxillare superius. L, The  maxilla inferior. M, l'he teeth of
both jaws.  N, The seventh, or last cervical vertebra. O, The spi-
nous processes. P, Their transverse and oblique processes. Q, The
twelfth or last dorsal vertebra. R, The  fifth, or last  lumbar verte-
bra. 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  ante-
rior spinous processes.  Y, The posterior spinous processes. Z, Is-
chiatic niche, a, The right os ilium,  b, The ossa pubis,  c, The tu-
berosity 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 me-
tacarpal 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 ex ernal condyle,  s, The  rotula. t,  The tibia,  u, The
fibula v, The malleolus externus. w, The astragalus,  x, The os
calcis. y, The os  naviculare. z, The  three ossa cuneiformia.  1,
The os cuboides 2, The  five metatarsal bones  3, The two bones
of the great toe. 4, The three bones of each ol 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. BB, The
 orbitar plates of the frontal bone. C, The  crista galli, with cribri-
 form plate of the ethmoidal bones on each  side of it, through
 which the first pair of nerves pass. D, The cuneiform process  of
 the occipital bone. E, The cruciform ridge. F, The foramen mag-
 num for the passage of the spinal  marrow. G, The  zygoma, made 
»/
tf&
 
 
           Explanation of the Plates of Osteology.           7

by the joining of the  zygomatic processes of the os temporum
and os malae. H, The pars squamosa of the os temporum. I, The
P^s mammillaris. K. Ihe  pars petrosa. L, The temporal pro.
cess of ihe sphenoid bone. MM, The anterior clinoid processes
r*, the posterior  clinoid  process. O, The sella turcica. P,  The
loramen opticum, for the passage of the optic nerve  and ocular
anery of the left  sule. Q, The foramen lacerum, for the third,
w?S* SrXlh' and fi'St of lhe fif,h l>air of  nerres antl oc"l*r vein
K, I he foramen rotundum, for the second  of the fifth  pair. S, The
foramen ovale, for the thud of he fifth pair. T, I he foramen spi-
nalc-, tor the principal artery of the dura mater  U, The  entry of
the ai.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 twodentes incisorts of the right side. B, The  dens ca-
ninus. C, The  two small  molares  D, The three large molares.
E, I he 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  sutures.
G, The foramen palatinum posterius, for the palatine vessels and
nerves.  H, The os maxillare  superius of the right side  I, The os
n alae. K, The zygomatic process of the temporal bone. L, The
posterior extremity of the  ossa spongiosa. M, The posterior  ex-
tremity of the vomer, which  forms  the  back part of the septum
nasi.  N, The pterygoid  process of the right side of the  -phenoid
bone. OO,  The foramina ovalia. PP, The foramina spinalia. QQ,
The passages of the internal carotid arteries.  R, A hole  between
the point of each pars petrosa and cuneiform process  of  the occi-
pital bone, which is filled up  with  a ligamentous substance in  the
recent subject.  S, The passage of  the left lateral  sinus.  T, The
posterior condyloid foramen of the left side. U, The foramen mas-
toideum.  V, The foramen magnum. W, The  inferior orbitar fis-
sure. X, The glenoid cavity,  for the articulation of the lower jaw.
Y, The  squamous part of the  temporal bone. Z, The mastoid pro-
cess, at the inner side of which is a fossa for the posterior belly of
the digastric muscle, a, The  styloid process b, The meatus audi-
torius externus.  c, The  left condyle of the occipital bone, d, The
perpendicular occipital spine,  ee, The inferior horizontal  ridge of
the occipital bone  f f. The superior horizontal ridge, which is
opposite to the crucial  ridge  where the  longitudinal sinus divides
to form the  lateral  sinuses,  ggg. The lambdoid suture, h, The
left squamous suture, i, The  parietal bone.

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

        Fig. 5.  The posterior surface of the Ossa Nasi.
   A A, Their cavity, which forms part of  the  arch of the nose 
8          Explanation of the Plates of Osteology.
BB, Their ridge or spine, which projects a little to be fixed to the
fore part of the septum narium.

Fig. 6. The external surface of the Os Maxillare 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 h'>le.
E, The opening  into  the  nostril.  F,  The  palate-plate. G, The
maxillary tuberosity. H,  part of  the os palati. I, The two dentes
incisores'. K, The dens caninus.  L, The two small dentes molares.
M, The three large dentes molares.

Fig. 7. The internal surface of the Os Maxillare  Superius
                       and Os Palati.
  A, The  nasal process. BB, Eminences for the connection of
the os spongiosum inferius. D, The under end of the  lachrymal
groove. E, The antrum maxillare. F, The nasal spine, between
which and  B is the cavity of the nostril.  G, The  palate plate. H,
The orbitar part of the os palati  I, The  nasal plate. K, The su-
ture which unites the  maxillary and palate bones. L, The ptery-
goid process of the  palate bone.

     Fig.  8. The external surface of the right Os Unguis.
  A, The orbitar part. B, The lachrymal part. C, The ridge be-
tween 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  this is irregular, where  it covers part of the ethmoidal
cells.
      Fig. 10. The external surface of the  left Os Malje.
  A, The  superior  orbitar  process. B, The inferior orbitar  pro-
cess. C, The malar process. D, The zygomatic process.  E,  Ihe
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  pro-
cess. C, The malar process. D, The zygomatic process.  E,  The
internal orbitar plate or process.

Fig. 12. The external surface of the right Os Spongiosum Infe-
                            rius.
   A, The   anterior part. B, The  hook-like  process for covering
part of the antrum maxillare.  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 Spongiosum  Inferius.
   A, The anterior extremity. B, The  upper edge which joins the
superior maxillary  and palate bones. 
I I 
 
           Explanation of the Plates of Osteology.          9

Fig. 14.  The posterior and external surface of the right Os Pa-
                           lati.
  A, The orbitar process. B, The nasal lamella. C, The pterygoid
process.  D, The palate process.

Fig. 15.  The interior and external  surface of the right Os Pa-
                           lati.
  A, The orbitar process. B, An opening  through which the la-
teral 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 posterior part which receives  the processus
azygos 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 denscaninus. K, The two small
molares. L, The three large molares.

          Fig. 18. The different classes of the Teeth.
  1, 2, A fore and back view of the two anterior  dentes  incisores
of the lower jaw. 3, 4, Similar teeth of the upper jaw. 5, 6, A fore
and back view of the dentes  canini. 7, 8, The anterior dentes mo-
lares. 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 Hyoides.
  A,  The body.  BB, The cornua.   CC,  The appendices.

                       Plate  XXII.

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

  a, The posterior surface of the sternum,  bb, The broken ends
of the clavicles,   cccc, The tubercles near the extremity of each
clavicle,  d, The ligament connecting the  clavicles.

Fig. 2. A Fore-view of the Left Scapula, and of  a half oi  the
               Clavicle,  with their Ligaments.
  a, The spine of the scapula,  b, The  acromion,   c, The infe-
                             B 
10         Explanation of the Plates of Osteology*
 rior angle,  d, Inferior costa.  e, Cervix,  f, Glenoid cavity, co-
 vered with  cartilage for the arm-bone,  gg, The capsular liga-
 ment of the joint,  h,  Coracoid process,  i,  The broken end of
 the clavicle,  k, Its extremity joined to the acromion.   1, A liga-
 ment coming out single from the acromion to the coracoid process.
 m, A ligament coming out single from the acromion, and dividing
 into two, which are fixed to the coracoid process.

 Fig. 3.  The Joint of the elbow of the left arm,  with the  Liga-
                           ments.
   a, The os humeri,  b, Its  internal condyle,  cc, The two pro-
 minent parts of its trochlea appearing through the capsular liga-
 ment,  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 scaphoid bone of the car-
 pus, d, The os lunare.  e,  The os cuneiforme.  f, The os pisi-
 forme.   g, Trapezium,  h, Trapezoides.  i,  Capitatum.  k, Un-
 ciforme.   1,  The four metacarpal bones of  the fingers,  m,  The
 first phalanx,   n, The  second  phalanx,  o, The third phalanx.
 p, The metacarpal bone of the thumb,  q, The first joint,  r, The
 second joint.

  Fig. 5. The Posterior View of the Bones of the Left Hand.
   The explication  of Fig. 4.  serves for this figure; the same let-
 ters pointing out the same bones, though in a  different view.

 Fig. 6. The Upper Extremity of the Tibia,  with the Semilunar
    Cartilages of the Joint of the Knee, and some Ligaments.
  a, The strong ligament which connects the rotula to the tubercle
 of the tibia,  bb, The parts of the extremity of the tibia, covered
with cartilage, which appear within the semilunar cartilages,  cc,
The semilunar cartilages,  d, The two parts of what is called the
cross ligament.

  Fig. 7. The Posterior View of the Joint of the Right Knee.
  a, The os femoris cut.  b,  Its internal condyle  c, Its external
condyle,   d, The  back-part of the tibia,  e, The superior extre-
mity of the fibula,   f, The edge of the internal semilunar  carti-
lage,  g, An oblique ligament,  h, A larger perpendicular liga-
ment,  i, A ligament connecting the femur and fibula.

  Fig. 8. The Anterior View of the Joint of the Right Knee.
  b, The internal  condyle,  c, Its external condyle,   d, The pari
of the os femoris, on which the patella moves,  e, A perpendicular
ligament,  f f,  The two parts of the crucial ligaments,   gg,  The
edges of the two   moveable  sejnilunar cartilages,  h,  The tibia.
i,  The  strong  ligament of the patella,   k, The  back part of it 
Explanation of the Plates of Osteology.         11
 where the fat has been dissected away.  1, The external depres-
 sion,  m, The internal one.  n, The cut tibia.

 Fig. 9. A View of the inferior part of the Bones of  the Right
                            Foot.
  a, The great knob of the os calcis.   b, A prominence on its out-
 side,  c,  The hollow for the tendons,  nerves, and blood-vessels.
 d, The anterior extremity of the os calcis.   e, Part of the astraga-
 lus,   f, Its head covered with cartilage,  g, The internal promi-
 nence of the os naviculare.   h, The os cuboides.  i, The os cunei-
 forme  internum; k,—Medium; 1,—Externum.   m,  The  meta-
 tarsal bones of the four lesser toes,  n, The first—o, The second—
 p, The third phalanx of the four lesser toes,   q,  The metatarsal
 bones of the great toe.   r, Its first—s, Its second joint.

 Fig. 10.  The Inferior Surface of the two large Sesamoid Bones,
              at the first Joint of the Great Toe.

  Fig. 11. The  Superior View of the Bones of the Right Foot.
  a, b, as in Fig. 9. c, The superior head of the astragalus, d, &c.
 as in Fig. 9.

 Fig. 12.  The View of the Sole of the Foot,  with its  Ligaments.
  a, The great knob of the os calcis.  b, The hollow  for the ten-
 dons, nerves, and blood-vessels, c, The sheaths of the fiexores pol-
 licis and digitorum longi opened, d, The strong cartilaginous lig-
 ament supporting  the head of the astragalus,  e, h, Two liga-
 ments which unite into one, and are fixed to the metatarsal bone
 of the great toe.  f, A ligament from  the knob of  the  os calcis to
 the metatarsal bone of the little toe.  g, A strong triangular liga-
 ment, 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 lig-
 amentum rotundum connecting it to the acetabulum, c, The cap-
 sular ligament of the joint with its  arteries injected,   d, The nu-
 merous vessels of the mucilaginous gland injected.

 Fig. 14.  The Back-view of the Cartilages of  the Larynx, with
                       the Os Hyoides.
  a,  The posterior part of the base of the os hyoides.  bb, Its cor-
 nua.  c,  The appendix of the right side, d, A ligament sent out
 from the appendix of the left side, to the styloid process of the tem-
 poral bone, e, The union of the base with the left cornu. t f, The
 posterior sides of (g) the thyroid cartilage,  hh, Its superior cor-
 nua.  ii, Its inferior cornua.  k, The cricoid cartilage. 11, The
 arytenoid cartilages,  m, The entry into the lungs,  named glottis.
n, The epiglottis,  oo, The superior cartilages of the trachea,  p,
 Its ligamentous back-part. 
12       Explanation oj tne nates of the Muscles.

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 ligamentous substance  in
which they are formed.
    EXPLANATION OF PLATES XXIII. and XXIV.

                      PLATE XXIII.

  Fig. 1. The Muscles  immediately under the common tegu-
ments 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 occipitofrontalis.  C,
Attolens aurem  L), The ear. E, Anterior auris. FF, Orbicularis
palpebrarum. G, Levator labii superioris alaeque nasi. H, Leva-
tor anguli oris.   I, Zygomaticus minor.  K, Zygomaticus major.
L, Masseter.  M, Orbicularis oris.  N, Depressor labii inferioris.
O, Depressor anguli oris. P,  Buccinator. QQ, Platysma myoides.
RR. Sterno-cleido-mastoidxus.  S, Part of the trapezius.  T, Part
of the scaleni.
  Superior Extremity—U, Deltoides.  V, Pectoralis major.
W, Part of the latissimus dorsi. XX, Biceps flexor cubiti.  YY,
Part of the brachialis externus.  ZZ, The beginning of the tendi-
nous aponeurosis (from the  biceps),  which  is spread over the
muscles of the fore-arm. aa, Its strong tendon inserted into the tu-
bercle of the radius, bb, Part of the brachialis internus. c, Prona-
tor radii teres, d, Flexor carpi radialis. e, Part of the flexor carpi
ulnaris.  f, Pal maris longus. g, Aponeurosis palmaris. 3, Palmaris
brevis. 1, Ligamentum carpi annulare.  2 2, Abductor minimi di-
giti  h, Supinator radii longus.  i, The tendons of the thumb,  k,
Abductor pollicis. 1,  Flexor pollicis longus.  mm, The tendons of
the flexor sublimis perforatus,  profundus perforans,  and  lumbri-
cales.—The  sheaths are entire in the  right hand,—in the left cut
open to show the tendons of the flexor profundus perforating the
sublimis.
  Muscles  not  referred to—in the left superior extremity.—n,
Pectoralis minor, seu serratus anticus minor, o, The two heads of
(xx) the biceps,  p, Coraco-brachialis.  qq, The long head of the
triceps extensor cubiti. rr, Teres major, ss, Subscapularis.  tt,
Extensores radiales.  u, Spinator 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, Abductor minimi digiti.  5, The four lumbri-
cales. 
 
 
Explanation of the PI tes of the Muscles.        13
   Trunk.—6. Serrated extremities of the serratus anticus major.
 7 7, Obliquus externus abdominis.  8 8,  The linea alba.  9,  The
 umbilicus  10. Pyramidalis.  1111, The spermatic cord. On the
 left side it is covered b\ the cremaster.  12  12, Rectus abdominis.
 13, Obliquus  internus.  14 14, 8tc. Intercostal muscles.
   Inferior Extremities—qo, The gracialis. b b, Parts of the
 triceps,  cc, Pectialis.  dd. Psoas magnus.  ee, Iliacus internus.  /,
 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 membranosusi
 Its tendinous aponeurosis covers (i) the vastus externus on the right
 side  mm. Patella,  nn,  Ligament or tendon  from it to the tibia. 0,
 Rectus cruris. /;, Crurasus. 9 g, The tibia, rr, Part of the Gemellus.
 or gastrocnemius externus. sss, Part of the  soleus or gastrocnemi-
 us internus. t, Tibialis  anticus. u, Tibialis  posticus, vv, Peronaei
 muscles,   wvt, Extensor longus digitorum  pedis,   xx, Extensor
 longus pollicis pedis, y, Abductor pollicis pedis.

 Fig. 2. The Muscles, Glands,  &c. 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 alaequi nasi!
'e, Levator anguli oris,  f, Zygomaticus. g, Depressor labii inferi-
 oris.   h, Depressor anguli oris,  i, Buccinator,  k, Masseter.  II,
 Parotid gland, m, Its duct, n, Sterno-cleido-mastoidaeus. o, Part
 of the trapezius,  p, Sterno-hyoidaeus.  q, Sterno-thyroidaeus.  r,
 Omo-hyoidaeus.   f,  Levator scapulae,  tt,  Scaleni.  u, Part of the
 splenius.

 Fig. 3. The Muscles of the Face and Neck in view after the ex-
                  terior ones are taken away.
   aa, Corrugator supercilii.  b, Temporalis, c, Tendon of the le-
 vator palpebrae superioris.  d, Tendon of the orbicularis palpebra-
 rum,  e,  Masseter.  f, Buccinator,  g, Levator anguli  oris, h, De-
 pressor labii superioris alaeque nasi, i, Orbicularis oris, k, Depres-
 sor anguli oris.   1, Muscles of the os hyoides.   m, Sterno-cleido-
 mastoidxus.

 Fig. 4. Some of the Muscles of the Os Hyoides and Submax-
                         illary Gland.
   a,  Part of the masseter muscle, b, Posterior head of the digas-
 tric,  c, Its anterior head, dd, Sterno-hyoidaeus. e, Omo-hyoidaeus.
 f,  Stylo-hyoidaeus. g, Submaxillary gland in situ.

           Fig. 5.. The  Submaxillary Gland and Duct.
   a,  Musculus mylo-hyoidaeus. b, Hyo-glossus. c, Submaxillary
 gland extra situ.  d} Its  duct. 
14        Explanation of the Plates of the Muscles.
                       Plate XXIV.

  Fig. 1. The  Muscles immediately  under the common tegu-
ments on the posterior 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.
  Head.—AA, Occipito-frontalis. B, Attollens aurem.  C, Part
of the orbicularis palpebrarum. D, Masseter. E, Pterygoidaeus in-
ternus.
  Trunk.—Right side.  FFF, Trapezius seu cucularis GGGG,
Latissimus dorsi. H, Part of the obliquuis externus abdominis.
  Trunk___Left side.  I, Splenius. K, Part of the complexus. L,
Levator scapulae. M, Rhomboides. NN, Seratus posticus inferior.
O, Part of the longissimus dorsi.  P, Part of the sacro-lumbalis.
Q, Part of the semi-spinalis dorsi. R, Part of the serratus anticus
major. S, Part of the obliquus internus abdominis.
  Superior Extremity.—Right side.  T, Deltoides  U, Triceps
extensor cubiti.   V, Supinator longus.   WW, Exten&ores carpi
radialis longior and brevior.  XX, Extensor carpi  ulnaris.  YY,
Extensor digitorum communis.   Z, Abductor indicia.  I 2 3,  Ex-
tensores pollicis.
  Superior Extremity.—Leftside, a, Supra Spinatus. b, Infra-
spinatus,  c,  Teres minor,  d, Teres major, e, Triceps extensor
cubiti. ff, Extensores carpi radiales.  g, Supinator brevis.  h, Indi-
cater. 1 2 3,  Extensores pollicis. i,  Abductor minimi digiti. k,
Interossei.
  Inferior Extremity.—Right side.  1, Glutaeus maximus. m,
Part of the Glutaeus medius. n, Tensor vaginae femoris. o, Graci-
lis,  pp, Abductor femoris magnus. q, Part of the vastus internus.
r, Semimembranosus,  s, Semitendinosus.  t, Long head of the bi-
ceps flexor cruris,  uu, Gastrocnemius externus seu gemellus, v,
Tendo Achillis. w, Soleus seu gastrocnemius internus, xx, Pero-
naeus 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, fifi, q, r, s, t, v, w iv,
x x, y, z, Point the same parts as in the right side,  c, Pyriformis.
b b, Gemini,  c c, Obturator internus.  d, Quadratus femoris. e,  Coc
cygaeus. /, The short head of the biceps flexor cruris,  g g, Plan-
taris. h, Poplitaeus. i, Flexor longus pollicis pedis.

Fig. 2. The Palm of the Left Hand after the common Teguments
       are removed, to show the Muscles of the Fingers.
  a, Tendon of the flexor carpi  radialis.   b, Tendon of the flexor
carpi ulnaris.   c, Tendons of the  flexor sublimis perforatus,  pro-
fundus perforans and lumbricales.  d, Abductor pollicis.  ee, Flexor
pollicis longus.  f, Flexor pollicis brevis.  g, Palmaris brevis. h,
Abductor minimi digiti. i, Ligamentum carpi-annulare. k, A probe
put  under the  tendons of the flexor digitorum sublimis;  which
are performed  by  1,  the flexor digitorum profundus,  mmmm,
Lumbricales. n, Abductor pollicis. 
 
 
 
^
r   ^
 
Explanation of the nates of the Muscles.
15
Fig. 3. A fore-view of the foot and Tendons of the Flexores Di-
                          gitorum.
  a, Cut extremity of the tendo Achillis. b, Upper part of the as-
tragalus,  c, Os calcis. d, Tendon of the tibialis anticus. e, Tendon
of the extensor pollicis longus. f, Tendon of the peronaeus brevis.
g, I endons of the flexor digitorum longus, with the nonus Vesalii.
hh, The whole of the flexor digitorum brevis.

                Fig. 4. Muscles of the Anus.
  aa, An out line of the buttocks,  and  upper part of the thighs.
b, The testes contained in the scrotum, cc, Sphincter ani. d, Anus.
e, Levator ani. ff, Erector penis,  gg, Accelerator urinae. h, Cor-
pus cavernosum urethae.

                Fig. 5. Muscles of the Penis.
  aa, b, d, ee, f f, h, point the same as in fig. 4. c, Sphincter ani.
gg, Transversalis penis.
 EXPLANATION of PLATES XXV. XXVI. and XXVII.

                       Plate XXV.

Fig. 1. Shows the Contents of the Thorax and Abdomen Incitu.
  1. Top of the trachea, or wind-pipe.  2 2, The internal jugular
veins.  3 3, The subclavian 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.

Fig. 2. Shows the Organs subservient  to the Chylopoietic Vis-
          cera,—with those of Urine and Generation.
  11, The under side  of the two great lobes of the liver,  a, Lo-
bulus spigelii. 2, The ligamentum rotundum. 3, The gall-bladder.
4, The pancreas. 5, The spleen. 6 6, The kidneys. 7, The aorta
descendens.  8, Vena cava ascendens. 9 9, The renal veins cover-
ing the arteries. 10, A probe under the spermatic vessels and a bit
of the inferior mesenteric artery, and over the ureters. 1111, The
ureters.  12 12, The iliac arteries and veins.   13, The rectum in-
testinum.  14, The  bladder of urine.

Fig. 3. Shows the  Chylopoietic Viscera,  and Organs subservient
             to them, taken out of the Body  entire. 
16        Explanation of tne Mates of the Muscles.
  AA, The under side of the two great iobes of the liver. B, Lig-
amentum rotundum.  C. The gall-bladder.  D, Ductus cyvticus.
E, Ductus hepaticus.  F, Ductus communis choledochus. (t, Ve-
na portarum. H, Arteria hepatica.  II, The stomach. KK,  Vtnae
and arteriae gastro-epiploic^, dextrae and sinistrae.  LL, Venae and
arleriae coronariae ventriculi, M, The spleen. NN, Mesocolon, with
its vessels. OOO, Intestinum colon P, One of the ligaments of the
colon, which is  a bundle of longitudinal muscular fibres  QQQQ,
Jejunum and ilium   RR, Sigmoid flexure of the colon wi' ■> the
ligament continued, and  over  S,  The  rectum intestinum.  TT,
Levators ani. U, Sphincter ani. V, The place to which the pros-
trate 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
  between both Auricles.
  a, The right ventricle,  b, The left ventricle,  cc, The outer side
of the right auricle  stretched out.  dd, 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
inferior passing through g, A portion of the diaphragm.

Fig. 5. Shows the Heart and Large Vessels of a Fcetus at the full
                           time.
  a, The left ventricle,   b, The right ventricle,  c, A part of the
right auricle, d, Left auricle,  ee,  The right branch of the pulmo-
nary artery, f,  Arteria  pulmonalis.  gg, 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 carotid  artery,  n, The right carotid artery, o, The right sub-
clavian artery,   p,  The origin of  the right carotid and right sub-
clavian arteries in one common trunk, q, The vena cava superior
or descendens.  r, The right common subclavian vein, s, The left
common subclavian vein.
  N. B. All the parts  described in  this figure are to be found in
the adult, except the canalis arteriosus.

                        Plate XXVI.

Fig. 1.  Exhibits the  more superficial Lymphatic Vessels of the
                      Lower Extremity.
   A, The spine of  the os ilium   B,  Ihe  os pubis.  C, The iliac
artery.  D,  The knee.  E, E, F,  Branches of the  crural artery.
G,  The musculus gastrocnemius.  H, The tibia.  I, The tendon
of  ihe musculus tibialis anticus.  On the  outlines,  a,  A  lym-
phatic vessel belonging to the  top of the foot,  b, Its first division
into branches, c, c,c, Other divisions of t  e same l.mphatic ves-
sel, d, A small lymphatic gland   e, Tne lymphatic vessels which
lie between the skin and the muscles of the thigh, f f, Two lympha- 
 
 
          Explanation of the flates of the Muscles.        17

tic glands at tlie upper part of the thigh below the groin. ^, Other
glands,   h,  A lymphatic vessel which passes by the side of those
glands without communicating with ihem; and,  bending towards
the im-ide of the groin  at (i), opens into the lymphatic gland (k).
11, Lymphatic glands in the groin, which are common to the lym-
phatic vessels  of the genitals  und those 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 Extremity, dissected
  so as to show the  deeper-seated Lymphatic Vessels  which ac-
  company the Arteries.
  A, The os pubis.  B, The tuberosity of the ischium.  C, That
part of the os ilium which was articulated with the os sacrum. D,
The extremity of  the iliac  artery appearing above the groin.  E,
The knee.  FF, The two cut surfaces of the triceps muscle, which
was divided to show the lymphatic vessels that pass through its
perforation along with  the crural artery. G, The edge of the mus-
culus gracilis.  H, The gastrocnemius and soleus, much shrunk
by being dried, and  by the soleus being separated from the tibia
to expose the  vessels.  I, The heel.  K, The sole  of the foot. L,
The superficial lymphatic vessels passing over the knee, to get to
the thigh. On the out-lines; M, The 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 which the lymphatic vessel passes.
i,  The  lymphatic vessel passing with the crural artery,  through
the perforation of the  triceps muscle,   k,  The lymphatic vessel,
after  it has passed  the perforation of the triceps, dividing into
branches which embrace the artery (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 lymphatic 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.  BB,  The two jugular veins.  C,  The vena cava
Buperior. DDDD, The subclavian veins. E, The beginning of the
aorta, pulled to the left side by means of  a ligature, in order to
show the thoracic duct behind it.  F, The branches arising from
the curvature  of the aorta.   GG, The  two carotid  arteries.  HH,
The first rii.s   II, The trachea.   KK, The  spine.   LL, The vena
azygos.  MM,  The descending aorta  N, The coeliac artery, divi-
ding into three branches. O, The superior mesenteric artery. P,
The right crus diaphragmatis.   QQ, The two kidneys.  R, The 
 18        Explanatisn of the Plates of the Muscles.

 right emulgent artery.  SS, The external iliac arteries,  g d, The
 musculi psoae. T, The internal iliac artery.  U, The cavity of the
 pelvis.  XX, The spine of the os ilium. YY, The groins, a, A lym-
 phatic gland  in the groin,  into which lymphatic vessels from the
 lower extremity are seen to enter,  b b,  The  lymphatic vessels of
 the  lower extremities passing under poupart's ligament,   cc, A
 plexus of the lymphatic vessels lying on each side of the pelvis.
 d, The psdas muscle with lymphatic vessels lying upon its inside.
 e, A plexus of lymphatics, which having passed over the brim of
 the pelvis at  (c), having entered the cavity of the pelvis, and re-
 ceived the lymphatic vessels belonging to the viscera contained in
 that cavity, next ascends,  and passes behind the iliac,artery  to (§■).
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,  hh,
 The plexus lying on each  side of the spine,  i i i, Spaces occupied
 by the lymphatic glands, k, The trunk of the  lacteals, lying on the
 under side of the superior  mesenteric artery. I, 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
 under the right emulgent  artery, o, The thoracic duct penetrating
 the thorax,  fn Some lymphatic vessels  joining that duct  in the
 thorax, g, The thoracic duct passing under  the curvature  of the
 aorta to get to the left subclavian vein. The aorta being drawn aside
 to show the duct,  r, A plexus of lymphatic vessels passing upon
 the trachea from the thyroid gland to the thoracic duct.

                       PLATE XXVII.

 Fig. 1. Represents the Under and Posterior Side of the Bladder
                        of Urine, Sec.
   a, The bladder,  bb, The insertion of  the ureters, cc, The vasa
 deferentia, which convey the semen from the testicles to  dd, The
 vesicula seminales,—and pass through e, The prostrate gland, to
 discharge themselves into  f, The beginning  of the urethra.

           Fig. 2.  A transverse Section of the Penis.
   gg, Corpora cavernosa penis, h, Corpus cavernosum urethrae.
 i, Urethra, k, Septum penis. 11, The septum between the corpus
 cavernosum urethrae and that of the penis.

          Fig. 3.  A Longitudinal Section of the Penis.
   mm, The corpora cavernosa penis, divided by o, The septum
 penis,  n, The corpus cavernosum glandis, which is the continua-
 tion of that of the urethra.                    «

     Fig. 4.  Represents the Female Organs of Generation.
   a, That side of  the uterus which is next the os sacrum.  1, Its 
;■-■:$} 
 
 
 
          Explanation of ihe Plates of the Muscles.       \$

fundus.  2, Its cervix,  b b, The fallopian or uterine tubes, which
open  into the cavity of  the uterus;—but the other end  i3  open
within the pelvis, and surrounded by cc, The fimbriae,  dd, 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 pudendi. gg, The cut edges of the ligamenta lata, which
connects the uterus to the pelvis, h,  The inside of the vagina,  i,
The orifice of the urethra, k, The clitoris surrounded by (1), The
prxputium. mm, The labia pudendi.  nn, The nymphae.

Fig. 5. Shows the Spermatic Ducts of the Testicle filled with Mer-
                            cury.
  A, The vas deferens.  B, Its beginning, which forms the poste-
rior  part of the  epididymis.  C, The  middle of the epididymis,
composed 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 deferentia.  i i. The substance of the  testicle.

Fig. 6. The right Testicle entire, and the Epididymis filled with
                          Mercury.
   A, The beginning of  the vas deferens. B, The vas deferens as-
cending towards the abdomen C, The posterior part of the epidi-
dymis, named globus minor.  D, The spermatic 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.
          EXPLANATION of PLATE  XXVIII.

  This plate  represents the Heart in situ,  all the large Arteries
and Veins, with some of the Muscles, &c.
  Muscles, &c.—Superior Eextremity—a, Masseter. b,Corn-
plexus.  C, Digastricus. d, Os hyoides.  e, Thyroid gland, f, Le-
vator scapulae, g, Cucullaris.  h h, The clavicles cut. i, The deltoid
muscle, k, Biceps flexor cubiti cut.  1, Coraco-brachialis. m, Tri-
ceps extensor cubiti.  n, The heads of  the pronator teres, flexor
carpi radiales, and flexor digitorum sublimis,  cut. o, The flexor
carpi-ulnaris, cut  at its extremity, p,  Flexor digitorum profundus.
q, Supinator  radii longus, cut at its  extremity,   r, Ligamentum
carpi transversale. s, Extensores carpi radiales. t, Latissimus dor-
si. u, Anterior edge of the serratus anticus major, vv, The infe-
rior part of the diaphragm, w w, Its  anterior edge cut.  xx, The
kidneys, y, Transversus abdominis, z, Os ilium.
  Inferior. Extremity.—o, Psoas magnus. b, Iliacus internus. 
20        Explanation of the Plates of the Muscles.

c, The fleshy origin of the tensor vagina iemoris.  dd, The ossa
pubis cut Irom each other,  e, Musculus pectineus cut from its
origin, f, Short head of the triceps abductor femoris cut. g-, The
great head of the triceps,  h, The long head cut. z, Vastus internus.
k, Vastus externus. I, Crureus.  m, Gemellus, n, Soleus. o, Tibia.
p, Peronaeus longus. 9, Peionaeus brevis  r, Fibula.
   Heart and Blood-vessels.—A,  The heart, with the coronary
artery and veins.  B, The right auricle of the heart. C,  The aorta
ascendens.  D, The left subclavian  artery.  E, The left carotid ar-
tery.  F,  The common trunk which sends off the right subclavian
and right carotid arteries. G, The carotis  externa.  H, Arteria fa-
cialis, which sends off the coronary arteries of the lips.  I, Arteria
temporalis profunda. K, Aorta descendens.  LL, The iliac arteries,
—which   sends off  MM,  The  femoral or crural arteries.  JV. B.
The other arteries in this figure  have the same distribution 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 frontal vein. 2, The facial vein. 3, Vena
temporalis profunda. 4, Vena occipitalis. 5, Vena jugularis exter-
na. 6, Vena jugularis interna, covering the arteria carotis commu-
nis.  7, The vascular arch on the palm of the  hand, which is form-
ed by, 8,  The radial artery and vein, and, 9,  The ulnar artery und
vein.  10  10, Cephalic vein.  11, Basilic vein, that on the right side
cut.  12, Median vein. 13, The humeral veinj 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 jugu-
lars, 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.  2oJ*The vena profunda femoris, covering the
artery.  21, The upper part of the vena saphena major.  22,  The
femoral vein.  23 2:3,  The iliac veins.  24\24, Vena cava inferior.
25 25, The renal veins covering the arteries. 26 26, The diaphrag-
matic veins.
           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.
  A A, 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 infun-
dibulum.  F, The medulla oblongata, which sends off the medulla
spinalis through the spine. GG, That part of the os occipitis which
is placed above (HH) the transverse processes of the first cervical 
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Explanation of the Plates of the Muscles.       21
vertebra.  II, &c. The seven cervical vertebrae, with their inter-
mediate cartilages.  KK, &c. The twelve dorsal  vertebrae, with
their intermediate cartilages. LL, &c. The five lumbar vertebrae,
with their intermediate cartilages   M, The os sacrum.  N, The
os coccygis.
   Nerves—.1 1, The first pair of nerves,  named 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 occulij 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 ofithalmic, goes  to  the orbit,
supplies the lachrymal gland, and sends branches out to the fore-
head and nose.—The second, named superior maxillary, supplies
the teeth of the upper jaw, and  some of the muscles of the lips.__
The third, named inferior maxillary, is  spent  upon the muscles
and teeth  of the lower jaw, tongue, and muscles of the lips.  6 6,
The sixth pair,  which, after sending off the beginning of the inter-
costal  or  great sympathetic, is spent  upon  the  abductor 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 reflected branch from  the second of the fifth; and within
the tympanum,  by  a branch from the third of the  fifth, named
chorda tympani.—Vid.  fig. 3. near B.  8 8,  kc. The eighth pair,
named par vagum,—which  accompanies the intercostal, and is
spent upon the tongue, larynx, pharynx, lungs, and abdominal vis-
cera.   9 9, The ninth pair, which  are spent  upon the tongue.   10
10, &c. The intercostal, or great sympathetic, which is seen from
the sixth pair to the bottom of the pelvis on each side of the spine,
and joining with all the nerves of the spine;—in its progress sup-
plying the heart, and, with the par vagum, the contents of the ab-
domen aud pelvis.   11  II, The accessorius, which is spent upon
the sternocleido-mastoidaeus  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, Sec.) the phrenic nerves to the diaphragm, supply the
muscles and teguments that lie  on the side of the  neck and rbp of
the shoulder.   16 16,  The brachial plexus, formed by the fourth,
fifth, sixth, seventh  cervicals, and first dorsal nerves; which sup-
ply the muscles and teguments  of the superior 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 1,8, The five  lumbar pairs of nerves,
■which supply the lumber and abdominal muscles, and some of the
teguments and muscles of the inferior extremity.  19 19, The sa-
cro-sciatic, or posterior crural nerve, formed by the two inferior
lumbar, and three  superior of  the os sacrum.. This large nerve
supplies the greatest part of the muscles and teguments of the in • 
22       Explanation of the Plates of the Muscles.
ferior extremity. 20, The stomachic plexus, formed by the eighth
pair.  21 21, Branches of the solar or caliac plexus, formed by
the eighth pair and intercostals,  which supply the stomach and
chylopoietic viscera.  22 22, Branches of the superior and inferior
mesenteric plexuses, formed by the eighth pair and intercostals,
which supply the chylopoietic viscera,  with part of the organs of
urine and generation.  23 23, Nerves which accompany the sper-
matic cord.  24 24, The hypogastric plexus, which supplies the
organs of urine and generation within the pelvis.

Fig. 2, 3, 4, 5. Show different Views of  the  Inferior part of the
  Brain, cut perpendicularly through the Middle,—with the Origin
  and large Portions of all the Nerves which pass ou' 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 oblongata.  F,
The corpus olivare, in the side  of the medulla oblongata. G, The
medulla oblongata.  H,  The medulla spinalis.
  Nerves.—1 2 3 4 5 6 7 8 and 9, Pairs of nerves.  10 10, Ner-
vus accessorius, which comes from—11, 12, and 13, The three first
cervical nerves.
            EXPLANATION of PLATE XXX.

  Figure 1. Shows the Lachrymal Canals, after the Common
Teguments and Bones have been cut away.
  a^ The lachrymal gland,  b, The two puncta lachrymalia, from
■which the two lachrymal canals proceed to c, The lachrymal sac.
d, The  large lachrymal duct,  e, Its  opening into the nose,  f,
The carunca 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 sclerotica, and the ciliary vessels are seen passing over—c c,
The retina which covers the vitreous 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 Muscles of the Eye.
  a, a, The two  optic nerves before they meet,   b, The two op-
tic nerves conjoined, c, The right optic nerve,  d,  Musculus at-
tollens palpebrae  superioris.  e, Attollens oculi.   f, Abductor, gg,
Obliquus  superior, or trochlearis.  h, Abductor,  i, The  eve-
ball. 
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          Explanation of the Plates of the Muscles.       23

         Fig. 4.  Shows the Eye-ball with its Muscles.
  a, The  optic nerve,   b,  Musculus trochlearis.  c, Part of the
os frontis, to which the trochlea or pully is fixed, through which,
—d, The tendons of the trochlear^ pass,   e, Attollens oculi.  f,
Adductor oculi.  g, Abductor oculi.  h,  Obliquus  inferior,  i,
Part of the superior maxillary bone to which it is fixed,   k,  The
eye-ball.

  Fig. 5. Represents the Nerves and Muscles of  the Right Eye,
after part of the Bones  of the orbit  have  been cut away.
  A,  The eye-ball.   B.  The lachrymal  gland.   C, Musculus4
abductor oculi.  D, Attolhns.  E, Levator  palpebrae superioris.
F, Depressor oculi.  G, Adductor.  H, Obliquus superior,  with
its pully.  I,  its insertion  into the sclerotic coat.  K, Part pf the
obliquus inferior.   L, The anterior part  of the os frontis cut.  M,
The crista galli of  the ethmoid bone.   N, The posterior part of
the  sphenoid bone.  O, Transverse  spinous process of the sphe-
noid bone.  P, The carotid artery, denuded where it passes through
the bones.  Q, The carotid artery  within the  cranium.   R,  The
ocular artery.

  Nerves.—a a, The  optic  nerve.—b, The third  pair, c, Its
joining with a branch of the first branch of the fifth pafr, to form
I,—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 opthalmic.   h,  The frontal    ich
of it.  i, Its ciliary branches,  along with which the nasal twig is
sent to the nose,  k, Its branch to the lachrymal gland.   I,  The
lenticular ganglion,  m, The  second branch pf ^he fifth pair, na-
med superior maxillary,   n,  The third branch of the fifth  pair,
named inferior maxillary,  o, The sixth pair of nerves,—which
sends  off p, The  beginning of the great  sympathetic,  q,  The re-
mainder 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.
   AA, The  cut edges of the upper part of the cranium.  B,  The
two tables and intermediate diploe.  BB,  The  two hemispheres
of the cerebrum.  CC, 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.

Fig. 7. Represents the parts of the External Ear,  with the Paro-
          y         tid 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  lym-
phatic gland, which is  often found before the tragus.  1, The duct
of the parotid gland,  m,  Its opening into the mouth* 
24       Explanation of the Plates of the Muscles.
        Fig. 8. A view of the posterior part of the external ear, meatus
      auditorius, tympanum,  with its small bones and Eustachian tube,
      of the right side.
        a,  The back part of  the meatus, with the small cerumir ius
      glands,  b,  The incus,  c, Malleus, d, The chorda tympani.  e,
      Membrana  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 tympanum—its small bones, cochlea, and semi-
      circular  canals.
        a,  The malleus,  b, Incus,  with  its long leg, resting upon the
      stapes,  c, Membrana tympani.  d, e,  The Eustachian tube, co-
      vered by part of—f f, The musculus circumflexus palati.   1, 2, 3,
      The  three semicircular canals.   4,  The vestibule.  5,  The coch-
      lea.   6,  The portio mollis of the seventh pair of nerves.

      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 musculus hyo-glos-
      sus.  e,  The lingualis.  f, Genio-glossus.  g g, Part of the stylo-
      glossus. 
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