NATIONAL LIBRARY OF MEDICINE
             Washington
Founded 1836
U. S. Department of Health, Education, and Welfare
Public Health Service 
 
 
A
SYSTEM  OF  ANATOMY
FOR THE USE OF
STUDENTS OF MEDICINE.
BY CASPAR WISTAR, M. I?.

   PROFESSOR OF ANATOMY
           IN THE
   UNIVERSITY OF PENNSYLVANIA.
VOLUME II.
J9<n>
          PHILADELPHIA:
PUBLISHED BY THOMAS DOBSON AT THE STONE HOIJSE,
        No. 41, SOUTH SECOND STREET.
            William Fry, Printer.
                1814.
J**l 
District of Pennsylvania, to wit:
 • .*******•**   BE IT REMEMBERED,  That on  the  twenty-third
 • SEAL, J day of February, in the thirty-eighth year of the Inde-
 •*««**••••* pendence of the United States of America, A. D. 1814,
Thomas Dobson, of the said district, hath deposited in this office the
title of a book, the right whereof he claims as proprietor, in the words
following, to wit:
    " A 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."
  In conformity to the act of the congress of the United States, intitu-
led, " 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 encourage-
ment 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 to the arts of designingi
engraving, and etching historical and other prints."
                                      D. CALDWELL,
                           Clerk of the District of Pennsylvania"; 
CONTENTS OF VOL. 11.
                   PART VI.
   OF THE NOSE—THE MOUTH—AND THE THROAT,

                   CHAPTER I.
                    Of the JYose.

                    SECTION I.
                                               P»p:
Of the External Nose....."J
                    SECTION II.
Of the Cavities of the Nose.....5

                  CHAPTER II.
          Of the Mouth and the Salivary Glands.
Of the Mouth,.......U
Of the Salivary Glands.....25
                  CHAPTER III.
                   Of the Throat.
                    SECTION I.
Of the Isthmus of the Fauces     -    -          -    29
                    SECTION It
Of the Larynx      -     -      -             -     31
Of the Thyroid Gland......37
                    SECTION III.
Of the Pharynx   -   -    ^    -   -    -•    -i     38 
iv
CONTENTS,
                                                  Page
                    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
                     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 con-
                 nected with the Heart.

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

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

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

                   CHAPTER III.
               Of the Trachea and Lungs.

                     SECTION I.
Of the Trachea.......62
The  Black Glands on the Bronchiae                    64

                     SECTION II.
Of the Lungs    -.....-65
Thorax of the Foetus     ......    69
Physiological Observations, &c.     -    -     -    -    7J

                   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      -    -     -     -    83
Contents of the Abdomen    ...     .     _     86
                     SECTION II.
Of the Peritoneum     ---...     9 \ 
CONTENTS.
V
                                                   Tage
                    CHAPTER II.
     Of the OLsofihagus, the Stomach, and the Intestines.

                     SECTION I.
Of the CEsophagus       -      -     -          -     95
                     SECTION II.
Of the Stomach      -       -      -      -     -     97
Of the Gastric Liquor      -                        103
                     SECTION III.
Of the Intestines     -     -     -      -      -     106
Division of the Intestines     -     -    -    -    -     111
The Small Intestines     -     -    -      -     -     112
The Duodenum     -     -     -      -      -      113
Jejunum and Ileon     -    -    -    -    -    -     114
The Mesentery      -       -      -     -     -     116
Of the Great Intestines       -      -      -      -     119
The Caecum and Colon       -      -     -      -     120
The Rectum       -      -      -      -      -     124
The Omentum       -      -      -      -       -     126

                    CHAPTER III.
        Of the Liver, the Pancreas, and the Sfileen.
                      SECTION I.
Ofthe Liver     -                             -     129
                     SECTION II.
Ofthe Pancreas      -      -      -     ...     144

                     SECTION III.
Of the Spleen      -      -      -      -      -     146

                    CHAPTER IV.
      Ofthe Urinary Organs, and the Glandules Renales.
                      SECTION I.
Of the Glandulae Renales     -     -     -  .    .     15-5
                      SECTION II.
Ofthe  Kidneys and Ureters       -       -      -     158

                     SECTION III.
Of the Urinary Bladder     -     -       -      .     164

                    CHAPTER V.
             Of the Male Organs of Generation.
                      SECTION I.
Ofthe Testicles and their Appendages     -           173 
vi                   CONTENTS.
                                                   Page
                     SECTION II.
Of the Vesiculae Seminales and the Prostate Gland   -   183
                     SECTION III.
Of the Penis      -      -      -      -      -.     ™6

                   CHAPTER VI.
           Ofthe Female Organs of Generation.

                     SECTION I.
Of the External Parts of Generation       -      -     200

                     SECTION II.
Ofthe Vagina      .....    203
                     SECTION III.
Of the Uterus, the Ovaries, and their Appendages    -   205

                     SECTION IV.
Of the Bladder and Urethra       -       -      -      216
                    PART IX.
               OF THE BLOODVESSELS.
                    CHAPTER I.
Of the General Structure and arrangement ofthe Bloodvessels.
                      SECTION I.
Of the Arteries      .....     337

                     SECTION II.
Of the Veins       -      -      -      -       -     235

                    CHAPTER II.
  A Particular Account ofthe Distribution ofthe Arteries.
                      SECTION I.
Ofthe Aorta, or the Great Trunk ofthe Arterial System 238
                     SECTION II.
Of the Branches which go off from the Arch of the Aorta 240
The Carotid Arteries     -     -      -     .     -    241
The Subclavian Arteries    .....    258

                     SECTION IIL
Ofthe Branches which go off between the Arch and the
  Great Bifurcation of the Aorta    -                  274
Bronchial Arteries     -                   .     m     •« -.
GEsophageal Arteries     -----_    ,£,</
Inferior Intercostals    -                            ^fk 
CONTENTS.
vii
                                                     Page
Phrenic Arteries.......277
Coeliac Artery     -    -    -     -     -    - ,   -    ibid.
Superior Mesenteric Artery    ....     280
Inferior Mesenteric Artery.....282
Emulgent or Renal Arteries.....283
Capsular and Adipose Arteries     ....    ibid.
Spermatic Arteries     ....     .          284
Lumbar Arteries    -------    285
Middle Sacral Artery    ------   ibid.
                      SECTION IV.
Of the Arteries which originate at and below the Great
   Bifurcation of the Aorta    -----     285
The Primitive  Iliac Arteries    -     -     -     -    ibid,
Internal Iliac Arteries.....•■■    286'
External Iliac Arteries......291
Femoral Artery    -    --    -    -    -    -292
Arteries of the Leg......295

                     CHAPTER  III.
          Of the particular Distribution of the Veins.
                       SECTION  I.
Ofthe Superior, or Descending Vena Cava, and the Veins
   which communicate with it     -         -    -     30*3
Vena Azygos     ...    -     ...     304
Internal Jugular Veins......307
External Jugular Veins     -----     309
Subclavian Vein     -......310
                        SECTION II.
Ofthe Inferior Vena Cava, and the Veins connected with
   it.........313
Hepatic Veins    -     --    ---.314
Vena Portarum-   ---_--.     ibid.
Ei-mil&ent or Renal Veins.....315
Spermatic Veins    -    -    -     -    -    -    -316
Lumbar Veins.....-.          ibid.
MIudi<- Sacral  Vein    -_----     ibid.
Primitive Iliac Veins    ------    ibid.
Internal Iliac Veins    ...     ...     317
External Iliac     ...     -                    318
Femoral Vein     ...     -     ...     ibid..
Instances of Peculiar  Arrangement of the Veins    -     320
 Ofthe Pulmonary Arlery aud Veins       -      -     S2J 
viii
CONTENTS.
Uage
                     PART
                   OF THE NE
Nerves of the Brain
Of the Cervical Nerves
Nerves of the Diaphragm
Brachial Plexus
Nerves of the Arm
The Dorsal Nerves
Ofthe Lumbar  Nerves
The Sacral Nerves
Sciatic Plexus
Great Sciatic Nerve
Great Sympathetic Nerve
Nerves of the Heart
Nerves of the Abdominal Viscera


                    PART  XI.
            OF THE ABSORBENT VESSELS

                    CHAPTER I.
                       •s
Ofthe Absorbents of the Lower Extremities—the Abdomen and
                     the  Thorax.
                      SECTION I.
The Absorbents of the Lower Extremities       -      382
                     SECTION II.
The Absorbents of the Abdomen and Thorax     -     387

                   CHAPTER II.
Of the Absorbents ofthe Head and Neck, of the Ufifier Extre-
    mities, and the Ufifier Part ofthe Trunk of the Body.

                     SECTION I.
Ofthe Absorbents  of the Head and Neck    -     -    397
                     SECTION II.
Of the Absorbents of the Arm, and Upper Part of the
  Trunk-      -       -       -      -      -      398
■v.
.VES.
                    328
                    349
                    351
                    352
                    353
                    357
                    359
                    362
                    363
                    364
                    367
                    369
                    374 
       SYSTEM OF ANATOMY.

                   PART VI.

OF  THE NOSE: THE MOUTH: AND THE THROAT.
                   CHAPTER  I.
                   OF THE NOSE.

 1 HE prominent part ofthe 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 56.
  After thus acquiring a knowledge of the bony structure,
the student will be prepared for a description of the softer
parts.
  Vol. II.               A 
2
                     SECTION I.
               Of the External Nose.
   THE  superior part of the nose is formed by the ossa
nasi, and the nasal processes ofthe upper maxillary bones,
which have been already described; (see vol. I, pages 34—
37.) 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 cavitie-s 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 direction,
until it reaches the lower part of the orifice of the nose, at
the junction of the palatine processes of the upper maxilla-
ry bones; where a bony prominence is formed, to which it
is  firmly united. The  upper  part of the anterior edge of
this cartilage, which is in contact with the ossa nasi, is flat,
and is continued into two lateral portions that are extend-
ed 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 continuations 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 
                     Of the Nose.                    3
ring, which is placed obliquely on the side of the septum:
so that the extremity of the oval points downward and for-
ward, 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  alse  or
lateral parts of  the nostrils.
   When the  external integuments and  muscles are remo-
ved from the lower portion ofthe 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 car-
tilages and the ligament above described; but being attach-
ed to one edge only of these cartilages,  the orifice formed
by them is complete.
   The internal portions ofthe 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 movable upon
the edge of the middle cartilage. 
4,            Motions ofthe Apertures, &rc.
   The orifices of the nostrils, thus constructed, are dilated
by thai portion of the muscle, called Levator Labii Superi-
ors Alitque Nasi, which  is inserted into the alae nasi.
They are drawn down by the depressor labii superioris
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 are 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 considered as
a portion of this muscle by many anatomists,  but were
described by Albinus as a separate muscle, and called Na-
salis 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 men-
tioned. 
5
                     SECTION II.
             Ofthe  Cavities ofthe Nose.
   TO the description ofthe osseous parts of the nasal cavi-
 ties in vol. I, page 56, 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 nasal lamella
 of the ethmoid bone above, and  with  the vomer below.
 This plate sends off those lateral portions already descri-
 bed, 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 Nares, which
 are formed  by the palate bones, the vomer, and the body
 of the sphenoidal bone, and are somewhat oval in figure.
   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 ofthe
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 mucus membrane; but he adds,
that it is almost impossible to separate them.
   It has  been supposed  that many  distinct glandular bo-
  * Conrad Schneider, a German professor, in a large work, " De Ca-
Urrhis," published about 1660. 
6              Schneiderian Membrane.
dies were to be seen in the structure of this membrane by
examining the surface next to the bones;* but this opinion
is  adopted  by very few of the anatomists of the present
day. The texture ofthe membrane appears to be uniform;
and on its surface are a great number of follicles of various
sizes, from which flows the mucus ofthe 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-
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 surface of
the nasal cavities. Two of them are generally found on
the septum  of the nose: one, which is small, passes for-
wards near the middle; the other, which is  much larger,
is  near the lower part of it.
   Two small arteries called  the anterior and posterior eth-
moidal, which are branches of the  ophthalmic, enter  the
              ' See Winslow, section X. No. 337. 
                  Olfactory Nerves.                 7
nose by foramina of the cribriform of the ethmoidal bone.
These arteries pass from the orbit to the cavity of the cra-
nium, 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  palatine 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-
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 intermediate
 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 
 8     Spheno-palatine and other Nerves ofthe Nose.
 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 membrane,
 and most probably terminate on the internal villous sur-
 face;  but  they  have not been traced to their ultimate ter-
 mination.  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 differ-
 ent ramifications unite so as to form a plexus.
   Dr. Soemmering published last year, some very  elegant
 engravings ofthe nose, representing one of his dissections,
 which appears to have been uncommonly minute and suc-
 cessful.* These represent the ramifications as becoming
more expanded and delicate in the progress 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
    *  They are intitled, Icones organorum humanorum olfactus 
         Extent ofthe' Schneiderian Membrane.        9^
some fibrillae, descends upon the anterior part of the sep-
tum to the point ofthe 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 exclu-
sively 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 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 exacdy like that which is above.
  The surface of the nasal cavities and their  septum, when
covered with  the  Schneiderian  membrane, corresponds
with the osseous surface formerly described. The mem-
brane 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 ofthe ethmoid, and lines it; the filaments
ofthe olfactory nerve passing through the foramina of that
bone  into the fibrous surface of the membrane.  It is con-
  Vol. II.                 B 
10     Distribution ofthe Schneiderian Membrane

tinued 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 fora-
mina  or openings of the sphenoidal cells, it lines these
cavities completely; but in these, as well as the other cavi-
ties, 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 the
fold therefore extends  lower  down  than the edge ofthe
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 
           on the Internal Surface ofthe Nose.         I \
 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, ia which
 the Schneiderian membrane lines the nose, than it is in the
 bare bones. A portion of the aperture in the bones is clo-
 sed by the Schneiderian membrane, which is extended over
 it: the remainder ofthe aperture is unclosed; and through
 this  foramen, the membrane is reflected so as to line the
 whole cavity. As a portion of the foramen is cove'red 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 extended over the fo-
 ramen in the bone, it must be doubled; or, in other words,
 a part of the aperture ofthe 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 ofthe ethmoid bone, which has a  curved
 or semicircular figure.  Near this prominence, in the same
 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. 
12  Eustachian Tube___Observations respecting the Nose.

            Orifice ofthe 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
      animal economy:  they afford a surface for the expan-
      sion ofthe olfactory nerves; and a passage for the exter-
      nal 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 apertures in the windpipe, the function of smelling
      is not performed. It is rather  in confirmation of this
      proposition, 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
       finally arranged with great  delicacy. It is certain  that
       the impressions from whence we derive the perceptions
       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 
         Use ofthe Sinuses ofthe Nose.           13
  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  ofthe vegetable gums in several particulars; and
  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 par-
  takes  more or less of the yellow. It is probable that aa
  incipient 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,
  villous nor flexible as that lining the nose, it may be con-
  cluded, 5 priori, that they are not concerned in the func-
  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  perfec-
  tion.  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
  effect 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 cheeks to the
upper and lower jaws; so that the teeth and the alveoli of
both jaws may be considered as within the cavity. Above,
it is  bounded principally by the palatine processes of the
upper maxillary  and palate bones, and the soft palate,
which continues backward from them in the same direc-
tion. Below, the cavity is completed by several muscles,
which proceed from almost the whole internal circumfer-
ence 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 connected to this
surface, and may be considered  as resting upon and sup-
ported by it.
  To acquire an idea of the parietes of this cavity, after
studying the upper and lower maxillary bones, the orbicu-
laris oris and the muscles connected with it, especially the
buccinator, ought to be examined; and also the digastricus,
the mylo-hyoideus, genio-hyoideus, and genio-hyoglossus.
By this it will appear that the lips and cheeks, and the ba-
sis or floor of the mouth, are formed in a great measure by
muscles.  Upon the internal surface of these muscles, a por-
tion  of cellular and adipose substance is arranged, as well
as glandular bodies of different sizes; and to these is at-
tached the membrane which lines  the inside ofthe mouth.
  This membrane passes from the skin of the face to the
lips,  and the inside ofthe mouth;  and, although it is really 
             Internal Surface ofthe Mouth,           15
a continuation of the  skin, there is so great a change of
structure, that it ought to be considered as a different mem-
brane. At the orifice of the lips it is extremely thin, and so
vascular that it produces the fine florid colour which ap-
pears there in health. It is covered by a cuticle, called by
some anatomists,  Epithelium, which has a proportionate
degree of delicacy, and can be separated like the cuticle in
other parts. When this cuticle is separated, the lips and the
membrane of the  mouth, appear to be covered with very
fine villi, which are particularly apparent in some prepara-
tions ofthe lips after injection and maceration.*
  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 ofthe 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 periosteum.

  * Ruysch had a fine preparation of this structure. See Thesaurus VII
Tab. Ill Fig-. 5. 
 16       Gums—Surface ofthe Hard Palate.
 The teeth appear to have passed through apertures in this
 membrane, and are surrounded by it closely at their res-
 pective 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 structure
 is not perfectly undertsood.            •***■
   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 ofthe 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 glandular bo-
dies, whose ducts open on the surface  of the palate.
  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 appli-
ed to it, their  respective tastes will be perceived, although
they have not been in contact with the tongue.
  The membrane is continued  from the bones  above men-
tioned to the soft palate, or velum pendulum palati, which
is situated immediately behind them. This soft palate may
be considered as a continuation of the partition between
the nose and fnouth: it is attached to the posterior edge of 
                  Soft Palate—Uvula.               17
the palatine processes ofthe ossa palati, and to the ptery-
goid processes of the sphenoidal bone. Its interior struc-
ture is muscular. The upper  surface is covered 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-pha-
ryngei below.  (See Vol. I. page 187—188.) Thus com-
posed, the soft palate constitutes the back part ofthe par-
tition between the nose and mouth. When viewed from
before, with the mouth open, it presents towards the tongue
an arched surface, which continues downward 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 in-
clude a triangular space.  They are called the lateral half
arches of the palate. Each of them is formed by a plait or
fold of the skin, and contains one of the two last mention-
ed muscles: the anterior, the constrictor 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 arises from
the posterior edge of the ossa palati, at the suture  which
  Vol. II.                C 
18                     Tongue.
connects them to each other, and, passing posteriorly across
the soft palate, extends from the basis to the  apex of the
uvula, into which it is inserted. By the action of this mus-
cle, the  length of the uvula can be 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
litde 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 ofthe 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
qf 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 », 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 sterno-
hyoidei muscles, which connect it to the upper part of the 
               Connexions ofthe Tongue.            19
sternum; by the coraco-hyoidei, which pass to it obliquely
from the scapula; by the thyro-hyoidei, which pass to it di-
rectly upward from the thyroid cartilage: all of which con-
nect it to parts below. To these should be added the stylo-
hyoidei, wiiich pass to it obliquely from behind and rather
from above; the mylo-hyoidei,  which come rather ante-
riorly from the lateral parts of the lower jaw; and the ge-
nio-hyoidei, which arise from a situation directly anterior
and  superior, the chin. When these muscles are a- rest,
the situation of the os hyoides is, as above described, below
the angles ofthe 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
ofthe tongue;  for the posterior extremity of  that organ is
attached to it; and of course the movements  of the bone
must have an immediate effect upon those ofthe 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 substance.
This connexion is such, that the edges of the tongue are
perfectly free and unconnected; and so is the anterior ex-
tremity for a considerable distance from  the apex towards
the base.
  The substance of the tongue consists principally of mus-
cular fibres intermixed with a delicate adipose  substance.
It is  connected to the os hyoides by the hyoglossus mus-
cle and also by some other muscular  fibres, as well as by 
20            Structure ofthe Tongue.
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 described; for that
cartilage is attached by ligaments to the os hyoides.
   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 intrinsic: (Vol. I, page 184.) they are situa-
ted near the under surface of the tongue, one on each side,
separated from each other by the genio-glossi muscles, 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 in-
sertion 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
totague in the middle ofthe  posterior parts of it. 
             Upper Svrfaoe of the Tongue.            21
   The hyo-glossi and the stylo-glossi, being continued into
the posterior and lateral parts, co&tribvfte 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 between
it and these muscles is  divided into two  lateral  parts by
the above described genio^glossi.  In the space above men-
tioned, is-a small salivary gland, of an irregular oval form;
the greatest diameter of which extends from before back-
wards; and its edges present outwards and inwards. It has
-several excretory 4ucts, the orifices of which form a line
on each side of the tongue. This gland is very prominent
jinder the tongue; and when the tongue is raised it is par-
ticularly 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 con-
siderably; and on this surface it constitutes the organ of
taste.
   The upper surface of the tongue, although it is continued
from  the thin membrane above described, is formed 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 PapilUe.
The  largest of these are situated on the  posterior part of

  * M. Bichat appears to have had doubts whether the real rete muco-
sum existed here. He says that he could only perceive a decussation of
vessels in the intervals ofthe papillae, which, as he supposes, occasioned
the florid colour ofthe tonjfue 
  22              Papillae of the Tongue.
  the tongue, and are so arranged that they form an angle
  rather acute, with its points backwards.  They  are com-
  monly nine in number:  they resemble an inverted cone;
  or, are larger at their head than their basis. They are situ-
 ated in pits or depressions, to the bottoms of which they
 are connected.  In many of them there are follicles, or per-
 forations, which  have occasioned them to be regarded as
 glands.  They are called Papillae Maxima', or Capitatce.
   The papillae, 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 are  scattere\i
 over the upper surface ofthe 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 surface
 of the tongue.  Although they are called conoidal, there is
 a great difference  in their form; many of them being irre-
 gularly 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.*

  * In the explanation of the plates, referred to in the following sen-
 tence, Soemmering observes, that when the fibrillx ofthe lingual nerve
 ofthe fifth pair are traced to the papillae ofthe second class, they swell 
              Bloodvessels of the Tongue.            23
  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, exist in
them.. These vessels are  arranged in a serpentine direc-
tion, and are  prominent  on the surface; but they appear
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 membrane
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 fraenum lingua:. It is attached  to the middle 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

out into a conical form; and these nervous cones are in such close con-
tact with each other, that the point of the finest needle could not be
insinuated into the papillae without touching a nerve- 
24             Nerves of the Tongue.
sublingual gland, and extends near to the symphysis of the
under 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.
  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 glossopharyngeal portion of the eighth pair, send-
ing off several branches in its course, passes to the tongue
near its basis, and divides into many small branches, which
are 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 the mylo-hyoideus,
and another to communicate with the lingual branch of the
fifth  pair, they are spent principally upon the genio-glossi,
and linguales muscles.
  The tongue answers a threefold purpose.  It is the  prin-
cipal 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. 
Parotid Gland.                 25
                 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
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 derived
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 exterior 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

  * For a general account of glands, see the appendix to this  volume.
  Vol. II.                 D 
2%      Submaxillary and Sublingual Glands.
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 digastric
muscle and the  ninth pair of nerves internally. Its poste-
rior 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 excretory
duct, which is of considerable length, and passes  between
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 glan-
dular bodies, which seem to be  appendices of the sublin-
gual 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 covered 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 
            Saliva.—Motions of the Tongue.         27
 greatest length is from before backwards;  its position is
 rather oblique, one edge being placed obliquely  inwards
 and upwards, and the other outwards and downwards. It
 has many short excretory ducts^ which open by orifices
 arranged  in a line on each side:  they are discovered 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 com-
 municates 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
 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 Glandulx  Molares.

    The motions of the  tongue are very intelligible to a per-
      son who has a preparation ofthe lower jaw before him,
      with the tongue  in its natural situation, and the mus-
      cles, which influence it, properly dissected. Its com-
      plicated  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
      connected. The muscular fibres ofthe tongue itself are
      also to be taken into this view, as they act a very im-
      portant part.
    Although the tongue  appears very necessary, in a me- 
28            Observations on the Tongue.
       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 distin-
       guish different 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.
     Of the three nerves which go to the tongue, it is gene-
       rally supposed that the lingual  portion  of the third
       branch of the fifth pair is most immediately concerned
       in the function of tasting, as it passes to the front part
       of the surface of the tongue. The glosso-pharyngeal
       are probably concerned  in the same function  on  the
       posterior part, while the ninth pair of nerves seems prin-
       cipally 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.

  * There is a very interesting paper on this subject, in the Memoirs
of the Academy of  Sciences  for the year 1718, by Jutsieu; in which
he describes the case of a female, fifteen years old, examined  by him-
self, who was born without a tongue. In this  paper he refers to ano-
ther  case, described  by Holland, 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
rjf a few letters; and also enjoyed the sense of taste. 
29
                  CHAPTER III.
                  OF THfe THROAT.
 lO avoid circumlocution, the word throat is used as1 a
general term to comprehend the structure  which occurs
behind the nose and mouth, and above the oesophagus and
trachea. This structure consists,
  1st, Ofthe parts immediately behind the  mouth, which
constitute the Isthmus of the Fauces:
  2d, Of the parts, which form the orifice ofthe windpipe,
or the Larynx;-—and
  3d, Of the muscular bag, which forms the cavity behind
the nose and mouth that terminates in the  oesophagus, or
the Pharynx.


                    SECTION I.
           Ofthe Isthmus ofthe 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 muscu-
lar  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 termi-
nates near the commencement of the uvula.  The posterior
plait runs obliquely downwards and backwards, as it con-
tains the palato-pharyngeus muscle,  which passes from the
palate to the upper and posterior part of the thyroid car-
tilage. 
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  mucus  ducts, which dis-
charge the mucus of the throat, for the purpose of lubrica-
ting the surface, and  facilitating the  transmission of solid
food.
   The epiglottis, or fifth cartilage of the larynx, is situated'
at the root of the tongue, in the middle, between the ton-
sils. The part which is in sight is nearly 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 epi-
glottis is so arranged that it forms a plait, which extends
from the middle of the root of the tongue along the middle
of the  anterior surface of the epiglottis, from its base up-
wards.
   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 some-
times remain; and a small fraenum, similar to that above
described, is often  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 knowledge 
            Cricoid and Thyroid Cartilages.          31
of the structure.  Thus, looking into the mouth, 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.
                   Ofthe 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 upwards:
in consequence of this, it has but little depth before, but
is eight or nine lines deep behind.
   The Thyroid cartilage is a single plate, bent in such man-
ner 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 cartilage, 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 angular part of the thyroid car-
tilage  forms a notch; and the natural position of the carti-
lage is such, that this part is very prominent in the neck: it
is called the Pomum Adami. 
 32       Arytenoid Cartilages and Ligaments.
   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  movable  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 the 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 si
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
membrane, it is oval in its upper extremity, and rather an-
gular below, terminating in a long narrow process 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  i?
perforated by the orifices of many mucus ducts.
  Vol. II.                 E 
 34             Ventricles of Morgagni.
   There 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,
 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 larynx,
 and, covering the upper ligaments, penetrates into the va-
 cuity between them and the lower ligaments, so as to form
 a cavity on each side of the larynx, opening between the
 two ligaments, which is called the Ventricle of Morgagni.
 The shape of these cavities is oblong. Its greatest length
 extends from behind forward, on each side of -{he opening
 into the windpipe formed by the two lower  or  principal
ligaments; so that when the larynx is removed  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 orifice of the ven-
tricle of Morgagni. 
Rima Glottidis.—Glottis.
35
  The aperture between the twd 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
from  below, the  structure appears still more  simple: it
resembles a septum fixed abruptly in the windpipe, with
an aperture in  it ofthe 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, tfhich 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 firmness
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- 
36  Arteries and Nerves of Larynx.-General Observations.
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 glottidis, and relaxing or  extending
the ligaments 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
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 
                    Thyroid Gland.                 37
      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 mo-
      dulation, 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 ofthe windpipe over the cricoid cartilage and a
portion of the thyroid. It lies behind the sterno-hyoidei
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 ofthe sub-
clavian.
   Notwithstanding this large supply of blood, there is no
proof that it performs any secretion; for although several
respectable anatomists have supposed that they discovered
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 however occurred,
in which air has been forced by  violent straining from the
windpipe into the substance of this gland. 
38
                    SECTION III.
                  Of the Pharynx.
   THE pharynx is a large muscular bag, which forms the
great cavity behind the nose and mouth that terminates in
the oesophagus.
   It has been compared to a funnel, of which the oesopha-
gus is the pipe; but it differs from a funnel in this respect,
that it is  incomplete in front, at the part occupied by the
nose and mouth and larynx.
   It is  connected above, to the cuneiform process of the
occipital bone, to the pterygoid processes ofthe sphenoidal,
and to both the upper and lower maxillary bones.  It is in
contact with the cervical vertebrae behind; and, opposite to
the cricoid cartilage, it terminates in the oesophagus.
   If the pharynx and oesophagus be carefully dissected and
detached from the vertebrae, preserving the connexion 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 ob-
vious.
   In this situation, if  an incision be made from above
downwards through the whole  extent of the posterior part
ofthe pharynx, the communication ofthe nose, mouth, and
windpipe, with this cavity, will  be seen at one view.
   The openings into the nose, or  the posterior nares, ap-
pear uppermost. Their figure is irregularly oval or oblong:
they are separated from each other by a thin partition, the
vomer.  Immediately behind, on the external side of each
of these orifices, is the Eustachian tube. 
              Structure ofthe Pharynx.            39
  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
mouth.  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 obliquely
downward and backward, and not parallel to the other.
  Close to the root ofthe 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
appendices, may be recognised at the posterior edge of the
glottis.  At a short distance  below this edge, the oesopha-
gus 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-
rout 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. 
40            Structure ofthe Pharynx.
   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
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 liga-
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 muscle arise from the thyroid
and the  cricoid cartilages, and terminate also in the mid-
dle line. Those which are superior, running obliquely up-
wards; the inferior, nearly in a transverse direction.
   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.
                OF 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 ofthe bulk of
the mammae.
  Vol. II.                F 
42                   Mamma.
   The gland however, varies  greatly in thickness in the
stome person at different periods of life.
   The mamma? become much enlarged about the  age of
puberty.  They are also very large during pregnancy and
lactation;  but after the period of childbearing, they dimi-
nish considerably. They 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 circumfe-
rence 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
         * Elementa Physiologise Tom. 7,  Pars 11. pag: 7. 
Mamma.
43
substance, 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
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  sebaceous
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 fro-m the great plexus
formed by the nerves ofthe arm. 
44
                   CHAPTER I.
       OF THE GENERAL CAVITY OF THE THORAX.

                    SECTION I.
     Of the form cfthe Cavity of the Thorax.
 I H E osseous structure of the thorax is described in
vol. I, page 88. Thecavity is completed by the intercostal
muscles, which close the vacuities between the ribs;  and
by the diaphragm, 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 considerably
influenced by the spine, which protrudes into it; while the
ribs, as they proceed from the spine, curve  backwards,
and thus increase its prominency in the cavity.
  The diaphragm has a great effect upon the figure ofthe
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 ofthe cavity of the thorax resembles
that of  the hoof of the ox when its posterior part is pre-
sented forwards.

                    SECTION II.
         Ofthe 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 ofthe 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
direction, 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
windpipe and the bloodvessels,  which go to the lung:
it continues  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 form the great vertical septum of the thorax,
called Mediastinum. They are situated at  some distance 
 46                 Mediastinum.
 from each other;  and the heart, with its investing mem
 brane or pericardium, 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 ofthe 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 
              Preparation ofthe Thorax.            47
in front of the vertebrae: this is called the Posterior Medi-
astinum. It contains a considerable portion of 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 ofthe  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 sepa-
       rating 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
       obvious; and the sternum may now be divided  with  a
       saw throughout its whole length in the same direction;
       so that the division ofthe bone may correspond with the
       space between the laminae of the mediastinum. 
48             Preparation of the Thorax.

    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  vein 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
      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
      studied: the root of each lung, or its connexion with
      the mediastinum, may be seen perfectly; and the pre-
      cise situation of the lung, in its proper cavity, may be
      well conceived.
    After this, while the portions of the  sternum are separa-
      ted, the pericardium may be opened, and  the heart
      brought into view:  the attachment of the pericardium
      to the mediastinum, and to the diaphragm, may be seen
      with advantage in  this situation.  The portions of the
      sternum may now be detached from the ribs, with which
      they remain  connected; and further dissection may be
      performed 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 I.
                Ofthe Pericardium.
 I HE heart is inclosed by a membranous sac, which, up-
on 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 lamina: the inter-
nal of which  covers the heart, as has been already descri-
bed; while the external merely extends over the loose por-
   Vol. II.               G 
 50                   'The Heart.
 tion of the other, and blends itself with the mediastinum,
 where that membrane invests the great vessels.
   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.
                   Ofthe Heart.
  THE great organ of the circulation consists of muscular
fibres,  which are so arranged that they give  it a conical
form, and compose four distinct cavities within it.
  Two of these cavities, which are called Auricles, receive
the contents of the veins; the other two communicate 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
ofthe ventricles, and  consists of a smaller  proportion of
muscular fibres.  They appear like appendages ofthe heart,
while the ventricles compose the body of the viscus.

  * The pericardium has been so distended, by effusion m dropsy, that it
 has formed a tumor, protruding on the neck from  under the sternum
 This tumor had a strong pulsating motion. It disappeared completely
 when the other hydropic symptoms were i\ iicved. 
               Connexions of the Heart.             51
  The ventricles are very thick,  and are composed of
muscular fibres closely compacted.
  The figure of  the  heart is not regularly  conical; for
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 proceeds 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 ca-
vae, 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 at-
tached to  the mediastinum in its course downwards, after
making its great curve; and 4th, by the pericardium, which
is attached to the great vessels and to the mediastinum. By
these different modes the basis of the heart is fixed, while 
 52                  Right Auricle.
 its body and apex are perfectly free from attachment, and
 only contiguous to the pericardium.
   The external surface of the heart, being formed by the
 pericardium, is very smooth: under this surface a large
 quantity of fat  is bften found.
   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 venae cava*;. 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 ventricle,
 and lies loose on the right side of the aorta.  This  point
 has some resemblance to the ear of a dog, from which cir-
 cumstance the whole cavity has been called auricle; but by
 many persons the cavity is considered as consisting of two
 portions: the Auricle, strictly speaking; and the Sinus Ve-
 nosus, 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 cavae, at  their
junction, is not precisely the  same; but  they form  an
 angle,  which causes  this  indentation. The  anterior por-
tion ofthe 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 surface:
  - In  this description  the heart is supposed  to be in its natural
position. 
                   Right Ventricle.                 53
this is also the case with the point, or that part which is
strictly called auricle.
  These fasciculi are denominated Musculi Pectinati,fvom
their resemblance to the teeth of a  comb.
  That part of the  internal surface, which is formed by
the septum,  is smooth; and the whole is covered by a de-
licate 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 communica-
tion 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 auricle
and ventricle, is the orifice of the proper vein ofthe 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 margins pro-
ceed 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 
54                Right Ventricle.
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 columns
arise from the ventricle, and are connected with the ten-
dinous threads, which are attached to the margins 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 are in-
serted into another part. A third species are attached to
the ventricle  throughout their whole  length, forming
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 ofthe heart, which some of them run across in every
direction near the apex. They are all covered by a mem-
brane continued from the auricle and the tricuspid valves;
but this membrane appears more delicate and transparent
in the ventricle than it is in the auricle.
  A portion ofthe 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 valvulae 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 
                   Right Ventricle.                 55
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 continued;
but immediately within the orifice of the artery it is formed
into three semicircular folds, each of which adheres to the
surface ofthe 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 Corpusculum
Arantii,* which adds to the strength of the valve.  Each
of these valves, by its connexion with the artery, forms a
sac or pocket, the orifice  of which opens forward towards
the course of the artery,  and the bottom of it presents to-
wards the ventricle.  Blood will, therefore, pass from  the
ventricle into the artery,  and along it, without filling these
sacs;  and on the contrary, in this course, will compress
them and keep them empty. If it moves in  the arterv
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  be-
tween the artery and the heart, which will always exist
when the artery compresses (or acts upon) its contents. It
is demonstrable, by injecting wax into the artery, in a re-
trograde direction, that  these valves do  not  form a flat
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 retrograde injection. The  en-

  * After Arantius, a professor at Bologna, who first described it. 
 56                  Left Auricle.
 largements thus produced are called the Sinuses of Val-
 salva, after the anatomist who first described them. The
 valves are called Semilunar; and, although they are form-
 ed by a very thin membrane, they  are very strong.
   The Left Auricle is situated on the left side ofthe 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 portion,
 which constitutes the proper auricle, that proceeds from
 the upper and left part of the cavity, and is situated on the
 left side of the pulmonary artery.
   This auricle is lined by a strong membrane, from which
 the valves between  it and the ventricle originate:  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 describ-
 ed between the  right auricle and ventricle;  but with this
 difference, that the valvular ring is divided into two porr
 tions  only, instead of three, which are called Valvules
 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
 auricle into the  ventricle, but completely prevent its  re-
 turn 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
 auricle is closed.
   The Left Ventricle is  situated posteriorly, and to the 
              Muscular Fibres ofthe Heart.           57
 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.
   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 obliterated,
 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
  * 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 1, page 215.
  Vol. II.                H 
58               Coronary Vessels, &?c.
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 ofthe 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
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
left auricle and ventricle.*

  ♦ II was asserted by Vieussens at an early period, in the last century,
and soon afterwards by  Thebesius, a German professor, that there
were a number of small vessels in the texture of the heart, which open-
ed into the different cavities on both sides of it.
This 
                     The Great Vessels.                 59

   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.


                      SECTION III.

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.

  This assertion of a fact so difficult to reconcile with the general prin-
ciples of the circulation, was received with great hesitation: and al-
though 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 veins, and some others have
neglected them entirely.
  Thejsubject has lately been brought forward in the London Philoso-
phical Transactions for  1798, Part I, by a very respectable anatomist,
Mr. Abernethy, who states that he has often passed a coarse waxen
injection  from the proper arteries and veins of the heart into all the
cavities of that organ, and particularly into the Left Ventricle. But it -was
only in subjects -with diseased lungs that this seas practicable.
  The existence of this, communication between the coronary vessels
and the great cavities ofthe 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  provisiwn enabling the coronary ves-
sels to unload themselves, when the coronary vein cannot discharge
freely into the right auricle. 
 60                     Aorta.
   They are composed of a substance, which has a whitish
 color 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-
 monar)r 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 art-fry, 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 lamina of  the
mediastinum when they join the first rib on each side.
  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^ some-
 what  smaller, which is the left carotid; and a third, which
 is the left subclavian artery. 
     Pulmonary Artery and Veins and Vena Cava.    61
  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 vessel; 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
azygos.
   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 veins
which passes obliquely across the  sternum below its inner
edge, in the upper space between the laminae of the medi-
astinum. 
62
                  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.

                  Ofthe 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 oesophagus
 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 compose
 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 
              Structure ofthe Trachea.             63
to the bifurcation of the tube. Their number varies, in dif-
ferent 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 tuhe 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
probably 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 ofthe 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. 
64          Black Glands on the Bronchia.
   The internal coat of the trachea is a thin and delicate
membrane, perforated with an immense number of small
foramina, which are the orifices of mucous ducts.
   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 bronchia":
until the form of their cartilages is changed in  the lungs:
if it were only to accommodate the oesophagus, during the
passage of food, there would be  no occasion for its exten-
sion to the bronchiae.                  i
   At the bifurcation of the trachea, and on the bronchiae,
are a number of black colored bodies, which resemble
the lymphatic glands in form and texture. They continue
on the ramifications ofthe bronchiae some distance into the
substance of the lungs. Their number is often very consi-
derable;  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 
                  Root ofthe Lungs*.               65
to the thofacic duct, they are considered  as lymphatic
glands.

                    SECTION H.
                   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 contact
with some part of the internal surface of the cavity; but
when in a natural  and healthy state,  it is not connected
with any part except the laminae ofthe mediastinum. One
great branch of the trachea and of the  pulmonary 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 pulmonary veins return from the lung
to the heart.
  These vessels are inclosed in a membrane, which is con-
tinued over them  from the mediastinum, and extended
from them to the lung. Thus covered, they constitute what
has been called the Root ofthe 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 pul-
monary artery are rather above and before, and the veini
below and before them.
  Vox.. II.                I 
66               Color ofthe Lungs.
  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
to the inferior part of the lungs, from which the lower pul-
monary 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 trans-
parent.  They have, therefore, a  very  smooth surface,
which is kept moist by exudation from the arteries of the
membrane.
  The Color of the Lungs is different in different  subjects.
In children they are of a light red color; in adults they are
often of a light gray;  owing to the deposition of a black
pigment in the substance  immediately under the mem-
branes which form  their external surface. Their color is
often formed by a mixture of red and black. In this case
they are more loaded with blood, and the  vessels of the
internal membranes being distended with it, the  red color
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 some-
times 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  arc
unknown. 
                Structure ofthe Lungs.             67
  The lungs are of a soft spongy texture; and, in animals
that have breathed, they have always a considerable quan-
tity 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
membranes which compose them are  so thin and delicate
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 preparation be
made of a lung injected in this manner with force, the
■H»ax 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 dis-
tended when air is blown into the ramification.
  This cellular substance is formed into small portions of
various angular figures,  which are denominated Lobuli:
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 
68             Structure of the Lungs.
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 interstitial cellular membrane be inflated,
it will  compress  the lobuli. This cellular membrane  if
always free from adipose matter: it may be easily examin-
ed 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 labors of chemists and physiologists, that the
great object of respiration is to effect a chemical  process
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
tht- lungs. The veins which correspond with these arteries
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 ofthe air cells of thelungs and ofthe  rami-
fications of the bronchiae which lead to them., appears 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. 
69
             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.
   In the foetus it is of a pale red color; and during infan-
cy 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 color,  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 thy-
roid branches ofthe subclavians,from the internal mamilla-
ries, and the vessels of the pericardium and mediastinum.
                      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. On 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 
 70             The Thorax ofthe Fatus.
 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 into 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 transmitted
 from the system of the vena cava to the system of the
 aorta without going through the lungs, as  it must neces-
 sarily do in subjects who do not enjoy the foetal structure.
          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 ofthe 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 
                  General Observations.               71
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 ofthe
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.
                 The Lungs ofthe Fatus
   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 color 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."*

  * The student will derive much information respecting the publica-
tions on this subject, prior to 1804, from Dr. Bostock's Essay on Res-
piration.—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 Atmospheric 
 72               Cases of Malformation.
     The 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
       to preserve 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 color
       ofthe 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 ofthe heart; palpitation;
       laborious respiration;  sensations of great debility, Etc.:
       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 up-
       on 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.

Air by the Germination of Seeds, &c." by Ellis;—two very important
Communications by Messrs. Allen and  Pepys in the Transactions of
the Royal Society of London for 1808 and 1809;—and " Further Inqui-
ries into the Changes induced on Atmospheric Air." Also by Ellis.
  f Cases of this kind are related in several ofthe periodical publica-
tions on medical subjects.  Two of them were described by the late Dr. 
    Adhesion ofthe Lungs to the Thorax.        73

Marcet, in the first volume of the Edinburgh Medical
and Physical Journal.
  The blue color occurred in a young woman twenty-
one years of age, in whom it had never been observed
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, oedema 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 fierfect and natural state. The lungs were
free from tubercles, or any other appearance of disease.
Their substance seemed more comfiact 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 diafihragm, and to the pleura covering the
pericardium.—This case is the more  remarkable, be-
cause  numberless instances  have occurred in which
very large portions ofthe external surface ofthe lungs
have been found upon dissection to adhere to the inter-
nal surface of the thorax  without  the occurrence  of
such symptoms during life.
    It may be inferred, from a statement published by M. Du-
       puytrcn in a late volume ofthe Proceedings ofthe Na-
       tional  Institute of France, that the  oxygenation or de-
       carbonation ofthe  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,

William Hunter in the sixth volume of Medical Observations and In-
quiries, by a Society of Physicians in London; one (quoted by Dr. Good-
wyn) is in the Observationes Anatomicae of Sandifort; and another, by
Dr. J. S. Dorsey, has lately  been published in the first number of the
New England Journal of Medicine and Surgery.
  Vol. II.                 K 
74        Effects of Venous Blood on the Heart.
      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
      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  ofthe 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. « 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

  * These Memoirs are republished in the Eclectic Repertory of Phila-
delphia for April and October 1811. 
               Sentiments ofSabatier, &?c.             75

      the state of the blood in the arteries which penetrate its
      texture.*  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 blood 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 oeconomy.f Although his hy-
      pothesis respecting its particular use has not been re-
      tained by his countrymen, many of them have adopted
      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 fora-
      men ovale into the left auricle; while  the blood of the up-
      per  cava passes directly  into the right ventricle.  His
      opinion seems to be supported to a certain degree,
         1. By the direction in which the two columns of blood
      enter the auricle from the two venae cavae.
         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 um-
      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

  • It is  probable  that the contents of the great cavities of the heart
have no more effect upon its animation than the contents ofthe stomach
and bowels have upon the animation of those organs.
  f See Memoirs ofthe Academy of Sciences for 171/ and 1725. 
76               Sentiments of Sabatier
      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 arte-
      ries;  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 circulating  through the body: while
      on the other hand, the blood  which passed by  the ca-
      rotid  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 passing
      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 ne-
      cessarily pass  to the  head  and  upper  extremities:
      While the blood  which returns from these parts by the
      superior cava, must consequently pass from the right au-
      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-
      clavian, 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 nume-
      ral 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 cha-
       racter 8 answering equally well in the description of
       either subject.
         According to Sabatier, the  blood of the  placenta
       takes this peculiar course through the heart,inorderthat

  * See Sabatier's Paper on this subject in the Memoirs ofthe Acade-
 demy of Sciences, for 1774. 
        respecting the Fatal Circulation.          77
  some of it may be carried to the head and upper ex-
  tremities. But an additional reason may be suggested,
  which appears to be of great importance; viz. the sup-
  plying of  the  coronary or proper vessels of the heart
  with some ofthe same  blood.
    Tne heart of the  adult, as has been before stated,
  cannot act  without  its  proper or  coronary  arteries
  are supplied with arterial blood. The heart of the foetus
  perforins 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
  originate  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 distance from the orifices of the coronary arte-
  ries, that it certainly cannot enter ihem.
    The whole of this doctrine seems to be supported by
  a fact, veryfamiliar to accoucheurs, viz. the occurrence
  of death in the foetus whenever the circulation through
  the umbilical cord is suspended during fifteen or twenty
  minutes: for as the placenta imparts to the foetal blood
  a quality essential to life, some arrangement seems ne-
  cessary to provide for the equal distribution of the
  blood which comes 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,
  in which the venae cavae  opened into the right auricle,
  and  the pulmonary veins into the  left auricle, in the
  usual manner; but the aorta arose entirely from the
  right ventricle, and the pulmonary artery as completely 
78         Unusual Cases of Malformation.
      from the left.—The canalis arteriosus, however, passed
      from the pulmonary artery to the aorta, and the fora-
      men ovale existed. In this  case it is evident that the
      pulmonary artery must have carried back to the lungs
      the arterial  blood which came from them by the pul-
      monary veins, with a small  quantity of venous blood
      that passed  into the left auricle through the foramen
      ovale; 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 addi-
      tion 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 forego-
      ing, occurred lately in Philadelphia, and was examined
      by the author of this work. The venae cavae terminated
      regularly  in the right auricle, and the pulmonary veins
      in the same  regular manner in the left; but the pulmo-
      nary artery arose  from the left ventricle, and the aorta
      from the right. There wasno communication between these
      vessels by a canalis arteriosus; but a large opening exist-
      ed 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
      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 
              Foramen Ovale.                  79
livid; and this color  was always much increased by
the least irregularity of respiration.  His nails were
always livid.  He sometimes appeared placid, but more
frequently 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 res-
piration. 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 presence of disoxygenated blood in the aortic sys-
  tem.  It is probable, that the small size of the foramen
  ovale, the valvular  structure  which  generally  exists
  there, and the complete occupation ofthe left auricle by
  the blood flowing from the pulmonary veins, prevent
  the passage of blood from the right auricle to the left, in
  such persons; whereas, in the case in question, the open-
  ing between the  auricles was very large indeed, and
  there was no appearance of a valve about it.
    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, it may be added, that  the
  pulmonary veins,  in the foetal state, carry to  the  left 
80   Legallois on the Source ofthe Motion ofthe Heart.
      auricle 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 favor ofthe
       opinion that the motions of the heart are independent
       of the brain, may be stated the numerous cases in which
       the  brain has been deficient in children, who have not-
       withstanding lived the full period of utero gestation,
       and  even a short time after birth, and have arrived at
       their full size, with  every appearance of perfect vigor
       and  action in  the heart.  In support of the doctrine, that
       the  action of the heart is immediately dependent upon
       the  brain, it may be observed, that no organ ofthe 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 un-
       decided, if not incapable of solution;  although Cruik-
       shank and  Bichat* have  stated circumstances very fa-
       vorable to the opinion that the motions of the heart are
       independent of the brain.
         This question seems now to be settled by the ex-
       periments of Dr. Legallois, a physician of Paris, which
       prove, that in  animals who  have suffered decapita-
       tion, the action of the  heart  does not cease as an im-
       mediate consequence of  the removal of the head; but
                                                          >
  * See Cruikshank's Experiments on the Nerves and Spinal Marrow
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 co-sidered  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 Legallois' Paper.     81

    its cessation is an indirect effect, induced by the sus-
    pension of respiration. That respiration is immediately
    affected by decapitation, and depends upon the influ*-
    ence of the brain transmitted through the eighth pair
    of nerves. That the action ofthe heart will continue a
    longtime after decapitation, if inflation ofthe lungs, or
    artificial respiration, be performed; but, on the contra-
    ry, 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 destroyed portion soon cease to live.  By particular
    management 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 several hours each; and that to allow themselves suf-
    ficient time for reflection, they suffered an interval of a
    week to  take  place between the meetings. The com-
    mittee believe 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
    medulla oblongata from which the nerves of the eighth
    pair arise.
Vol. II.                L 
82    Brodie on the Source of the Motion of the Heart.
        2d. That the principle which animates each part of the
      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 immedi-
      ate influence 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
      detailed many very interesting experiments which in-
      duced 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 circumstances 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 reconcilable 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
      although they seem to prove incontestibly 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
   CONTENTS, WITH AN ACCOUNT OF THE PERITONEUM.

                   SECTION I.
                 Ofthe 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 
 84           Construction ofthe Abdomen.
 innominata, which contribute, for the purpose, the costae of
 the ossa ilea, as well as the pelvis.
   The general figure of this cavity partakes ofthe 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 costae 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
 many 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-

        * See the account of this tendon, vol. i. page 197. 
             Construction ofthe Abdomen.           85
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,
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 transrfiission ofthe 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 distention 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 contents 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 muscles may be
considered in some measure as antagonists of each other.
When the diaphragm descends, if the abdominal muscles
are passive, they are distended by  the contents of the ab-

  * The student of anatomy, when engaged with this subject, will be
gratified by the examination of Mr. Astley Cooper's plates relating to
hernix. 
 86             Contents ofthe Abdomen.
 domen, which are forcibly pressed from above;  but if the
 abdominal muscles act at the same time, an effort to dimi-
 nish the cavity in every direction takes place, and the con-
 tained parts are compressed with more or less force ac«
 cording  to the exertion made. This will be very evident
 upon examining the situation of the diaphragm and of the
 abdominal muscles. When their force 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-
 lae 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 ofthe
 Inferior Cava, and their great ramifications; with such of
 their branches as are appropriated to the Viscera ofthe
 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 ofthe Thoracic Duct, or the Great
Trunk of the Absorbent System,  with the large branches 
               Regions ofthe Abdomen.            87
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,
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 spa-
ces immediately within the lower ribs and their cartilages;
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 denominated
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 margin  of the
thorax, on one side, to the corresponding part on the oppo- 
 88        Situation ofthe Viscera, &?c. in the
 site side; and the lower transverse line from the upper-
 most part of the spine of one ileum to the same part ofthe
 other. These lines will mark the three great divisions. If
 then two parallel  lines are drawn directly  upwards, one
 from each ofthe superior anterior spinous processes ofthe
 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
 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
 will 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 cal-
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 ofthe epi-

  * 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 ofthe Abdomen.             89
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 the 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
to the left lumbar region;  from this it continues  into the
left 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 blad-
der.  This viscus, in males, is in contact  with the  last por-
tion ofthe  great intestine  called the Rectum, and with it
occupies almost  all of the cavity of the pelvis; while in fe-
males, 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 con-
tinues down the  spine until it approaches towards the pel-
   Vol. II.                M 
 90        Great Bloodvessels in the Abdomen.
 vis,  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 External Iliac,
 which passes under the crural arch to the  thigh, and the
 Internal Iliac,  or Hypogastric, which descends 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
 Caliac, 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 abdomen,
it also sends off a small branch for the intestines,  called
the Inferior Mesenteric.  Besides these vessels for the
chylopoietic viscera, the aorta sends off a large branch,
called Emulgent, to each kidney.
  The inferior, or ascending vena cava, is  situated on 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 correspond  to the
arteries of the kidneys; but it receives in its course no
veins which  correspond directly with the coeliac and me-
senteric 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 portarum, after it has furnished ma-
 terials for the secretion of bile. The vena cava, in its pas-
 sage 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 
                   The Peritoneum.                91
without dissection. 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 auri-
cle of the heart.


                    SECTION II.
                 Ofthe Peritoneum.
   THE abdomen, thus constructed and occupied, is lined
by a thin firm membrane called Peritoneum, which  is ex-
tremely smooth on its internal surface, and is intimately
connected with the cellular substance exterior to it. This
membrane adheres closely to the anterior, lateral, and su-
perior  portions of the surface of the abdomen; and is ex-
tended from the posterior surface so as to cover, more or
less completely, the  viscera of the cavity.  Those viscera
which  are  in  close contact  with  the posterior surface of
the abdomen, as some portions of the  large intestine, 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 mova-
ble to a distance from the posterior surface of the  abdo-
men, are covered by this membrane, which is  extended 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; Me-
socolon, when  it goes to the colon, one of the  larger intes-
tines; and Ligament, when it passes to some of the other
viscera. 
92                The Peritoneum.
   The peritoneum is a complete but empty sac, which is
fixed in the abdomen anterior to the viscera.  The anterior
portion of this sac forms the  lining to the anterior and
lateral parts of the surface of the abdomen; the posterior
portion covers the viscera, and forms the mesentery, me-
socolon, 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
laminae: and as the bloodvessels, nerves, and absorbents,
are all posterior to the peritoneum, they naturally pass be-
tween these laminae of the mesentery.
   Some of the viscera are much more completely invested
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 portiop
of the smaller intestinal  tube,  which  is  called jejunuip
and ileum, and the transverse portion of the large intes-
tine, called the arch of the colon, are invested by it in the
same way.  But a  considerable portion of  the duodenum
and the pancreas is behind it. The lateral  portions of the
colon are in close  contact with the posterior surface of the
abdomen, and the  peritoneum only covers that portip-p, 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 hps but a
partial covering from it, on its upper portion.
   The peritoneum, which covers the stomach, is extended
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 composed of 
                   The Peritoneum.                93
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 co-
lon, which they inclose,  and then continue to the back of
the abdomen, forming the  mesocolon. The part  of this
process which is bttween  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 viscus in
that cavity, is called, by some anatomists, " reflection;"
and the technical term refected membrane is therefore ap-
plied to a membrane distributed like the perito*oeun>
   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.
   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  compqsed  of two laminae, 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-—ascites.
This fluid appears to exude from the surface ofthe peri-
toneum when it is compressed in a living  animal, or in
one recently dead. It is probably effused from the extre- 
94                The Peritoneum.
mities 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 neighboring 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.  When it covers the kidneys and the psoas mus-
cles it is very lax and yielding. About the kidneys a large
quantity of adeps very commonly  collects in it. On the
psoas muscle it yields with but little resistance to the pas-
sage of pus, or any other effused fluid, as in the case of
the psoas abscess. 
95
                   CHAPTER II.
OF THE OESOPHAGUS, THE STOMACH, AND THE INTESTINES.


                    SECTION I.

                 Ofthe (Esophagus.

 1 HE (Esophagus 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
* See page 38. 
 96                The Oesophagus.
 strata of fibres; the exterior of which is nearly longitudi-
 nal in its direction, and the interior circular or transverse.
   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 ofthe 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. 
                 Form of the Stomach,.               97
   While the oesophagus is in the posterior mediastinum,
 it is in contact with several small absorbent glands, espe-
 cially when it first assumes a situation to the right of the
 aorta. These  glands were formerly believed to be particu-
 larly connected with this tube, but they are now considered
 as belonging  to the absorbent system. They are sometimes
 greatly enlarged.

                     SECTION II.
                   Ofthe Stomach.
   THIS most important organ, which occasionally exerts
 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,
 that at first view it seems membranous, but upon  exami-
 nation 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  anato-
 mists of different nations  to the wind sac of the musical
 instrument called the bag-pipe.* The  orifice in which the
 esophagus terminates is at a small distance from its largest

   * The student ought not to attempt to acquire an idea ofthe form of
 the stomach without demonstration, for a view of one moment will be
 more serviceable than a long description.
   Vol. II.                N 
 98            Position of the Stomach.
 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
 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 hypochon-
 driac region, and the  lesser  extremity  in  the epigastric
 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 for-
 ward than the cardia: both  orifices being in the epigastric
 region.  The position of the  stomach is oblique in two res-
 pects; 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 di-
 vided 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 movable at its othe"r 
         Changes in the Position ofthe Stomach.       99
orifice; for the extremity of the duodenum, into which it
is continued, is movable.
  The stomach is connected to the concave surface of the
liver by the  reflexion or continuation of the  peritoneum,
which forms the lesser omentum.  This membrane, after
extending over each surface of the stomach, continues
from  its great curve in the form of the large omentum,
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 stomach
undergoes considerable changes in its position. 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 curva-
ture forwards. When its anterior surface  is presented up-
wards,  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 muscu-
lar 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 
100         External Coat ofthe Stomach.
the liver to the lesser curve of the stomach in two delicate
laminae, which separate  when they approach the  stomach,
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 peritoneum  on every
part of its surface except two strips, one at the lesser and
the other at the greater  curvature. These strips  or unco-
vered places are formed by the separation of the laminae
above mentioned, which includes a triangular space bound-
ed by the stomach and these two laminae.  In these trian-
gular spaces, at each curvature ofthe stomach, are situated
the bloodvessels which run along the stomach in  those di-
rections, and also the glands which belong to the absorbent
vessels of this viscus. The peculiar arrangement of the la-
minae at this place is particularly calculated to permit the
dilatation of the stomach. 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 la-
mina? to  each other, are so likewise: when it contracts,
the bloodvessels appear  to recede  from it, and the laminae
are then applied to each  other.
  Where the peritoneum thus forms a coat to the stomach,
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, bloodvessels, &c. ap-
pear through  it.  If it is  carefully dissected from  the mus-
cular coat, it appears somewhat flocculent on that surface
which adhered to the muscular  fibres. It seems to be most
abundantly furnished with serous vessels; but it  has been
asserted  by Mascagni and Soemmering, that a large pro-
portion of its texture consists of  absorbent vessels. The
cellular  substance which connects this  to  the muscular 
      Muscular and Nervous Coats of the Stomach.   101
coat appears no way different from ordinary cellular mem-
brane.
   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. Besides 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-
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 color, 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 color, with  a tinge of red.  It is 
 1*02         Internal Coat ofthe Stomach.
 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 is 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 off. 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
 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  not 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 
                     Gastric Liquor.                 103
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 stomach
upon alimentary substances.*
  As the muscular coat of the stomach frequently varies
its dimensions, the villous and nervous coats, which have
no 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 stomach
they  are arranged in a  radiated manner, and sometimes
they  are observed in a transverse direction. They depend

  *  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 Concoc-
tione. Edinburgh, 1777.
  The Abbe Spalanzani. Dissertations relative to Natural History, &c.
The first volume ofthe English translation contains the author's disser-
tations on digestion, and also  the first paper  of Mr. Hunter, and the
Thesis of Dr. Stevens, as well as an account ofthe experiments of Mr.
Gosse of Geneva.
  In  addition to these there are several interesting  essays in  the
French, German and Italian languages, a compilation of which is to be
found in Johnson's " History of the progress and present state of Ani-
mal  Chemistry." See Vol. I. page 180. 
104                 The Pylorus.
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 intestine:
the fibres of this ring seem a part 01 the muscular coat pro-
jecting into the cavity of the stomach and duodenum. If a
portion of the lesser extremity of the stomach and the
adjoining part of  the  duodenum  be  detached, 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  membrane. It is evident
that when the parts are replaced so as to  form a cylinder,
this narrow fasciculus will form a ring in it. Thus ar-
ranged, the  circular fibres can readily close the lower ori-
fice 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 ofthe stomach are derived from the Caliac,
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 
          Lymphatics and Nerves ofthe Stomach.    105
are called the Superior Coronary or Gastric, the Hepatic,
and the Splenic. Besides the first mentioned branch, which
is distributed principally to the neighborhood of the car-
dia and to the  lesser curvature, the  stomach receives a
considerable branch from the hepatic, which passes along
the right portion of its great curvature, and has been called
the right gastro-epiploic, and  another from the  spleen,
which passes along the left portion 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 extre-
mity ofthe 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 com-
monly passes through them, notwithstanding their number
and size.*
   The nerves of the stomach are derived principally from
the two great branches of the par vagum, which accom-
pany the oesophagus and are mostly spent upon this organ.
It also receives branches from several plexuses, which are
derived from the  splanchnic portions of the intercostal
nerves.

  • Sabatier, however, in one subject observed white lines  on the sto-
mach, which he suspected to be lacteals. See his account ofthe absgr-
bents ofthe stomach.
  Vol. II.                 O 
106            The Intestines in general.
                    SECTION III.
                  Of the Intestines.
  THE intestines form a continued canal from the pylorus
to the anus, which is generally six times the length ofthe
subject to which they belong. Although the different parts
of this tube appear somewhat different  from each other,
they agree in their general structure. The coats or laminx
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 omentum from the whole  tube,
there being only a certain portion of intestine, viz. the
colon, from which such  a process of peritoneum is con-
tinued.
  The Muscular Coat, like that of the stomach, consists of
two strata, the exterior of which is composed of longitu-
dinal fibres, which adhere to the external coat, and do not
appear very strong. The other stratum, consisting of cir-
cular or transverse fibres, is stronger, as the fibres are more
numerous. It is observable that they adhere to the longi-
tudinal fibres: and they seldom if ever form  complete
circles.
  The cellular substance immediately within the muscular
fibres resembles the nervous  coat of the stomach in  its
firmness and density. It  is likewise so arranged as to form
many circular ridges on its internal surface, which support
to a certain degree the permanent circular plaits of the  in-
ternal 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 
              Villous Coat ofthe Intestines.          107
difference between these surfaces; for if a portion of the
small intestine be inverted, and then suspended in perfectly
transparent water, in  a clear glass, and examined with a
strong light, it will appear like the external surface 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, be-
tween 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 Valvula Conni-
ventes, which do not generally extend round the intestine,
but are segments of circles; they  are so near each other
that their internal edges, which are very movable, may be
laid upon the folds next to them, like tiles or shingles. It
is evident that this arrangement of the internal coat must
add greatly to its length. This coat is extremely vascular,
so that in the dead subject it  can be uniformly colored 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 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.

  • 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 injection further, and filled the follicles, or forced the mucus
-jut of them. 
108        Lieberkuhn on the Villous Coat.
   A very interesting account of the Villous Coat was pub-
lished in 1744, by Lieberkuhn, who was considered by his
cotemporaries as a most expert practical anatomist, and
was also very skilful in microscopical  examinations, for
which he was particularly calculated, as his natural powers
of vision were uncommonly strong. In this essay he refers
to his preparations, which were at Berlin, and which ap-
pear to  have excited great surprise in  the minds of the
members of the Academy of Sciences of Prussia, at a time
when one ofthe first anatomists 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 ca-
vity 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 ampul-
lula 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 presented, 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 discharged a fluid injected by the
arteries without passing through  the mucus follicles.
    Lieberkuhn died early, and left but one essay  on this 
            Hewson and others on the Villi.         109
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 "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. Cruikshank 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 
 110         Fyfe and others on the Villi.
 second, who studied anatomy at  Berlin, held a different
 opinion from Lieberkuhn.
   Mr. Fyfe, who has been much employed in the investi-
 gation of the absorbent system, and must be perfectly ac-
 quainted 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 ofthe subject. He says, that, besides the
 bloodvessels, each villus consists of a fine net-work 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, supposes
 Lieberkuhn to have been mistaken, and confirms the des-
 cription 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 vessels.*

  * 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 Humani, of
 Mascagni 
Ill
               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 then-
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 portions 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 perfecUy direct. A considerable portion
of the Great Intestine is fixed immovably in the abdomen,
while a large part of the Small Intestine is very movable.
   Each of these great portions of the intestinal tube is
subdivided into three parts.  Thus, in the Small Intestine,
there is apiece at the commencement called Duodenum,
a great part of which has  no coat from the  peritoneum,
and is immovably fixed in one situation; while all the re-
mainder of the  small intestine has a  uniform covering
from the  peritoneum, and  is very  movable.  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 
 112    Commencemcn t of the Small Intestines.
 which it descends to  the lower part again, when by a pe-
 culiar flexure it proceeds to the center of the  posterior
 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  Co-
lon;  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 movable and incomplete septum, which
divides the abdomen into an upper and lower apartment.
Above this septum are the stomach, with the commence-
ment of the duodenum, the liver, and  the spleen;  below
it, that portion of the small  intestine which is called jeju-
num and ileon, makes its appearance. The portion of the,
intestine which passes from the stomach to the jejunum,
and is called Duodenum, is  so much involved by the me-
socolon, that the greatest part of it cannot be seen without
dissecting the mesocolon from its connection with the back \
of the abdomen. For the duodenum proceeds backwards
from the pylorus, and passing down behind the peritoneum,
enters a vacant space between the two laminae of the me-
socolon; it  proceeds for some distance in this space, and
then emerges on the lower side ofthe mesocolon.  Here the
duodenum terminates, and the  small intestine then is in-
vested by the peritoneum in such manner as to form me-
sentery, which  continues with it  throughout its whole
course to the great intestine. This portion of the intestine,
although very uniform in its exterior appearance, as  has 
              Situation of the Duodenum.           113
been observed before, is divided into Jejunum and Ileon:
the Jejunum being the upper portion, whrch begins  at
the mesocolon; and the  Ileon the lower portion, which
opens into the great intestine.

                  Ofthe 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 movable, 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
  Vol.  II.                P 
 114  Orifices ofthe Biliary and Pancreatic Ducts.
 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,
 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 
          Distinction between Jejunum and Ileon.     115
 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,
 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
 Winslow 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 numer-
 ous, 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. 
116      Arrangement of Jejunum and 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 connecte4 with the mesentery, is laid into
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 ofthe pelvis are empty, a large portion
ofthe 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 nerves, 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 
            Construction ofthe Mesentery.         117
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 edge,
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 root  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
not plaited at its root, but perfectly smooth, and free from
every kind of fold. It begins to enlarge towards its circum-
ference, and enlarges to that degree, that it falls into plaits
or folds; precisely such as would exist in a semicircular
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 circumference. By
many additions of this kind, the circumference of a mem-
brane, which was  originally a  semicircle of  five or six 
 118            Root ofthe Mesentery.
 inches, may be extended so as to exceed greatly that of the
 mesentery. It seems of course impossible to form an accu-
 rate model of the mesentery with a single piece of mem-
 brane or paper; but it may be easilv made with clay, or any
 ductile substance. A model of this kind must necessarily be
 folded  after the manner of the  mesentery; and  its circum-
 ference, 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 ofthe mesocolon, at the left ofthe
 spine, and extends  downwards near to the  right iliac re-
 gion; crossing the spine obliquely.  When it is examined
 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, pasa
 most commodiously to the intestines between these laminae;
for they are connected with large trunks that lie  on or near
the spine,  and the root of the mesentery commences 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  diameter.
They are  very  numerous, and  scattered irregularly, but

  * A model, upon the plan first mentiqned, 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 if
 it the circumference 
          Appearance ofthe Cacum and Colon.       119
are seldom observed very near to the intestine. They are
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
respects. 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,
and are placed nearly at  equal distances from each other.
The spaces between these bands are marked by transverse
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 
 120             Position ofthe Cacum.
 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 color.
 On the left side  it passes down in the lumbar region, be-
 fore 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 intestine changes its course,  and passing  into the pel-
 vis, continues downward, in contact  with the sacrum and
 coccygis, 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
the part which  is  contained  in the  pelvis, is termed
Rectum.
  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 sur-
 face of the fossa covered  by the peritoneum; but a portion
is in close contact with the surface, and connected to it by
cellular membrane.  Its external  surface, covered  by the
peritoneum, is marked by two of the bands or stripes be-
fore mentioned, which proceed on it lengthways. 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 rounded extremitv of the 
                 Structure ofthe Colon.            121
caecum, situated anteriorly and internally, is  a small pro-
cess resembling an earth-worm in form and  size: this is
therefore  called Appendicula Vermiformis. It is hollow,
and communicates with the cavity of the caecum at the
place of junction; and, like the caecum, has its other extre-
mity 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 the  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 ofthe muscular coat of
the Cacum and Colon  are very delicate, and not numerous.
  The internal coat  differs  materially from that of the
small intestines, although at first view they  seem to re-
semble 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,
  Vol.. II.                 Q 
 122               Valve ofthe Colon.
 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 ofthe ileon with the great intestine
has been already stated 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 fold
must be that of a crescent; and that its two surfaces, with
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 ofthe
intestines at their  place of junction, and this structure is 
           Structure ofthe Valve ofthe Colon.       123
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  Mor-
gagni, as they were first described by that anatomist.
   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 ejected
matter is, that this  matter has been in the large  intestines.
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 
 124            Position of the kectum.
the intestine also, and thus retains it in its position. The
great arch ofthe 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, composed of adipose mem-
brane, varying in length from half an inch to an inch and
a half: these appear to be of the nature of the omenrura,
and are  therefore generally denominated Appendices Epi-
ploica.

                     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 in-
vested with the muscles called the sphincter and levator
ani. It is called rectum, because  in this course it is sup-
posed not to incline to either side; but it is often found on
one side ofthe 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
sometimes  been applied to that portion ofthe peritoneum
which is analogous to the mesentery and mesocolon.
The peritoneum does not extend  to the end of the rec-
tum;  for it is reflected at the lower part of the pelvis from

  * Morgr.gni and Haller supposed it to be commonly on the left ofthe
.middle line: Sabatier on the right. 
               Structure ofthe Rectum.            125
the rectum to the bladder, or uterus, and does not line the
bottom of the pelvis; so that the lower part of this intes-
tine, 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 inti-
mately connected with the sphincter ani.
   The internal coat is very vascular, but the villous struc-
ture is not apparent. Mucous follicles are also very numer-
ous; and there are likewise some distinct glandular bodies
exterior  to this coat, which  vary in size in different sub-
jects.
   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 circu-
lar fibres exterior to  it, sometimes forms longitudinal
folds, which have been called its columns; these often dis-
appear when the intestine is opened lengthways and spread
out.  By the contraction of the longitudinal fibres, the in-
ternal coat is  often thrown  into folds or doublings, that
must assume a transverse or circular direction: they occa-
sionally pass down through the sphincter, and form the pro-
lapsus ani. The  rectum  is most plentifully supplied with
bloodvessels,  to be described hereafter; and it may be ob-
served, that, on  the lower part of the internal coat, the
veins are particularly numerous.
   The internal coat ofthe rectum terminates abruptly just
within the anus,  and is united to a production of the skin,
which, like the covering of the lips, is  very delicate and 
 126    Absorbents and Nerves ofthe Intestines.
 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 at page 206, vol. I.
   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 pass-
 ing through the lymphatic glands,  which are so numerous
 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 ofthe Intestines are principally derived from
 the intercostals, or great sympathetics. From each of these
 nerves, while they are in the thorax, an important 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  nerve6 of the in-
 testines.

                     The Omentum
  Requires a separate description,  although several cir-
cumstances connected with its structure have been already
 noticed. It  often varies in its position; but when it is ren-
dered 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 bot-
 tom of the  abdomen.
  As has been already said, it is an extension of the peri-
toneum, in  two laminae, from the concave surface of the 
       Origin and Arrangement of the Omentum.    127
liver to the lesser curvature of the stomach; and these la-
minae, after surrounding  the stomach, come in contact
with each other near its great curvature. From this portion
of the stomach,  from  the commencement of the duode-
num, 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 por-
tion  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 stomach and
colon is called the Great Omentum, or the omentum gastro
colicum. There is also a process of peritoneum 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 laminae, 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 anterior
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, communi-
cates with the general  cavity of the abdomen by a foramen 
 128   Varieties in the Appearance ofthe Omentum.
 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 very liable to laceration merely by ad-
 hering to the fingers, if they are  dry. Winslow therefore
 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 corpulrnt, 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,
 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 Physiologic, vol. VI. pag: 381.
  Gavard. Traite de Splanchnologie, page 350.
  Dr. James Rush's Inquiry into the use ofthe Omentum. 
129
                  CHAPTER III.
     (fP THE LIVER, THE PANCREAS, AND THE SPLEEN


                    SECTION I,

                   Ofthe Liver.
 I HIS largest viscus of the abdomen, when in a healthy
condition, is of a reddish brown color. If it is taken out of
the subject, 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 it extends through the upper portion
of the epigastric into the left hypochondriac 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  th$
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, com*
   Vol. II.                R 
130        Lobes and Fissures ofthe Lher.
mences 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 ligament
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 li-
gament 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, k oblong, with two sides, and an angle continued 
                Ligaments of the Liver.            131
along its whole length, which extends from the transverse
fissure to the posterior margin of the liver. It is situated
between  the posterior part of the transverse fissure, or
ductus venosu9, 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 §>uartus 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 abdo-
men. The peritoneum above the liver is reflected to  the
upper  surface of it, and the peritoneum below it to  the
lower surface; so that two laminae of the peritoneum pass
from the lower part of the diaphragm at the  back of  the
abdomen to the posterior edge of the liver. These processes
ofthe 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 contact  with a portion of  the
tendon of the diaphragm, also uncovered by  pertoneum:
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 ofthe liver.
  The peritoneum of the right side of the diaphragm, and
of the abdominal muscles, as far down  as the umbilicus,
is extended to the liver, and joins  it on the  convex sur- 
 132         Mode of supporting the Liver.
 face immediately opposite to the  umbilical fissure.  The
 peritoneum from the left side  of these parts does the
 same; and as these reflections of the peritoneum are  con-
 tinued from so low a part as the  umbilicus, they are ex-
 tended  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 peritoneum forms the
 suspensory ligament. Besides these, the peritoneum on the
 lower side of the liver is so arranged, that it not only ex-
 tends 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 connec-
 tion, 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  sup-
 ported 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 ne-
cessary to counteract this tendency. It would move to the. 
      Acini ofthe Liver.  Proper Co'at ofthe Liver.  133
light, when we lie on the right side, if it were not in con«
tact 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
inches, when the position of the subject is  changed from
the horizontal to the erect. As it  is  in contact with the
dinphragm, 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

  • It has been fractured in the living body by external violence.
  \ 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, al-
though very thin. It was described by M. Laennec,  in Le Journal de
Medecine for 1803. 
 134      Vessels ofthe Liver. Hepatic Artery.
 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-
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  the great fissure,
at the spot where the prominences exist  called the porta;
bence 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 vessels and nerves, which are connected  toge-
ther by cellular membrane.
   It has  been already observed,  that the first great branch
sent off by the  aorta in the abdomen, the Caliac, 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 
                    Vena Portarum.               135
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 called
the cystic artery; and also some smaller branches: it passes
under the hepatic duct, and ramifies through the greatlobe
ofthe 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
also. It has been disputed whether the size of this artery
is greater than would be requisite for the nourishment and
animation ofthe 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-
senteric veins. The  great mesenteric  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 thtse 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 
 136                Hepatic Duct.
 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 s?ze  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
 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 which 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. 
          Hepatic Veins.  Nerves of the Liver.      137
  These three vessels are in contact with each other before
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 covered 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 as-
sisted the circulation of the vena portarum; but that idea
is now altogether abandoned. The hepatic veins, which
receive  the blood of  the hepatic artery and the vena por-
tarum, 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  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 he-
patic artery  to  which  they  correspond,  but  form very
large angles with them.  This is probably owing merely to
their termination 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  are sent off,
which form a network that is divided into the right and
left hepatic plexus. These plexuses surround  the hepatic
artery and the vena portarum, and accompany them in their
ramifications throughout the liver, being inclosed by Glrs*-
   Vol. II.               S 
138  Lymphatics. Glandular Substance ofthe Liver.
son's capsule.  They receive some threads from the sto-
machic plexus, formed by the par vagum. Although the
number of nervous fibres is very considerable, their bulk,
compared with that ofthe liver, is very small.
  The Lymphatics of the Liver are extremely numerous;
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 opposi-
tion to the valves. When all the surface is injected in this
manner, it has the color of the substance injected; as is the
case with  parts which are very vascular, when the  blood-
vessels 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 sur-
face, proceed through the diaphragm into the thorax in
their course to the thoracic duct.  Those which are deep
seated emerge from the liver at the portae, where the great
vessels enter, and unite with the thoracic duct in the abdo-
men, after passing through several glands. The lymphatics
ofthe lower surface unite with the deep-seated.
  The glandular or parenchymatous substance ofthe liver
is of a reddish brown color, and moderately firm consis-
tence.  When  it is cut  into, the cut surface exhibits the
sections  of the  branches  of  the  different bloodvessels
above-mentioned, and of the excretory ducts.  These ves-
sels are often distinguishable from each other. The section
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 ad- 
                Peculiarity ofthe Liver.            139
here 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 distinguishable.
   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 colored, 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
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 to 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 
 140              Gall Bladder and Duct.
 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.
   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

  * A c.-se 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 bile was
 "•-t the gall bladder, but it was less acrid than usual. 
                      Gall Bladder.                 141
also higher than the neck; and when he  lies on the righl
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 peritoneal
coat ofthe liver is extended from the surface ofthe 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 corres-
ponding to this artery empty themselves into the vena por-
tarum* The lymphatic vessels are united to those 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.

  • It has been justly observed by John Bell, that the veins would not
terminate thus, if bile were secreted by the gali bladder. 
 142     Ductus Communis Choledechus. The Bile.
   The biliary duct from the liver, after receiving the duct
 from the gall bladder, takes the name of Ductus Communis
 Choledochus. It is wider than either of the other ducts, and
near three inches in length. It passes clown before the vena
 portarum, and on the right of the hepatic artery, to the pos-
 terior surface of the right extremity of the pancreas.  It
passes through a small portion of that gland, and then per-
forates the muscular coat of the duodenum; 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
die 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,
s.o that the biliary and pancreatic fluids enter  the  duode-
num by the  same orifice; but sometimes  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
      to  have  arisen merely from the presence of a. large
      quantity of bile in the stomach; for they have gone off
      completely upon the  discharge of bile by vomiting.
        Notwithstanding these effects of bile in certain cases. 
                  The Bile.                   143
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-
lor, when mixed with acids. The color 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
eleven 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. 
144
The Pancreas:
                    SECTION II.
                  Ofthe 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 m contact with the duodenum, and
it extends from this intestine in a transverse direction to
the spleen, to which it is connected  by the omentum and
by bloodvessels. It is not invested by the peritoneum, but
is situated in the space which exists between the two  la-
minae 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 mesen-
teric vein, or main branch ofthe vena portarum; being con-
nected to these parts by cellular membrane. 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 appropriated to it; but instead of this, it receives
branches from the contiguous aperies., 
                   Pancreatic Duct.               145
  The arterial blood of this gland is partly supplied by the
splenic artery, which, in its course from the main trunk of
the cceliac to the spleen, while it  is in the  groove at the
edge of the pancreas, sends off into the gland one consi-
derable branch called the great  pancreatic, and  a num-
ber of small branches, which go off in succession.  In ad-
dition 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 color, and
also in texture; for it is of a dull  white color with a tinge
of red, and it appears to consist of small bodies of a gra-
nulated form, which are so arranged as to compose small
masses or lobes that are united to  each other by cellular
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-
  Vol. II.                 T 
 146               Size ofthe Spleen.
 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 Wirsungi,
 after an anatomist who published a plate of it.
   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.
                    Ofthe Spleen.
   THE Spleen is a flat  body of a blueish color, and au
 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

  * 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, but not immediately; extreme.
acidity of t/ie  matter rejected 
               Enlargement of the Spleen.           147
 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-
 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 open-
ed in the ordinary way: but in some cases of enlargement,
 after the intermitting fever, it has extended downwards,
 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 continued 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 ana-
 tomists have considered them as one  membrane: they are,
 however, very distinct at the great fissure, but the exter-
 nal coat is extremely thin. 
148             Vessels of the Spleen.
  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 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
arteriae 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
ofthe 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 
         Malpighi on the Structure of the Spleen.     149
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 accom-
pany them through the viscus.
  The spleen consists of a substance which is much softer
than that of any other viscus of the  abdomen.  This sub-
stance is made up either wholly or  in great part of the
ramifications of the splenic artery and vein, which are de-
monstrated by injections to be very minute and numerous
in this body. There are also many fine white cords, like
threads, which pass from the internal surface ofthe 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 immersed 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 func-
tion is not very obvious: for these reasons the structure
of this organ is a subject of very interesting inquiry.
  Malpighi, who took the lead in researches of this nature,
before  injections of the bloodvessels with wax  were in
Hrse, after  investigating the structure of the spleen by
long maceration, by boiling, by inflation, by the injection
of ink or colored fluids, and by examination with micro-
scopes, 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 appendices
of the  veins. He  also asserted, that a large number of
white bodies or  vesicles were to be found in those  cells. 
 150      Ruysch on the Structure ofthe Spleen.
 and throughout the whole substance of the spleen, which
 were  in bunches like grapes, and preserved their whitish
 color although the vessels around them were injected with
 a colored fluid. This description of Malpighi appears to
 have been admitted by some of the very respectable ana-
 tomists who were cotemporary with him; but it was most
 zealously opposed by Ruysch, who exhibited the spleen
 so completely injected with wax, that it appeared to be
^composed entirely of vessels.*
   Ruysch 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 ramifica-
 tions  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  publish-
ed 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

  * 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.           151
opinion that there was in the texture of the spleen a pulpy
substance which was not a mere coagulum, but which,
however, could not be injected.
   He derived his opinion from this fact  among  others.
After macerating the spleen a considerable time, and inject-
ing water into the vessels until it returned colorless, he in-
jected ink, and confined it some time in the vessels by tying
them:  he then allowed the ink to flow out of the ves-
sels, 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 substance. 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-
ed, but that Ruysch himself, in his own preparations, re-
moved 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 vessels in
a living animal, and removed the spleen with the ligatures
on the vessels. In this situation he boiled it, and then ex-
amined the appearance of the vessels and the pulpy sub-
stance.  From these, as well as his other observations, he
decided, that the pulpy substance did not consist entirely
of vessels, but was an additional and different structure.
   He also suggested, that as the brain and the muscular
fibres were so covered by bloodvessels in the injected pre-
parations of  Ruysch, that they appeared to be composed
entirely of vessels, when in fact  they consisted of a differ- 
 152 Haller and the French Anatomists on the Spleen.
 ent 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 majority
 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
 subject, 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;
 although he believed that  the  pulpy substance of  the
 spleen 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 transparency
 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 vessels; if 
            British Anatomists on the Spleen.        153
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 resembles
coagulated blood: whether this  is  contained in the capil-
lary vessels, or  in  the cavities of this organ, he acknow-
ledges 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 Professor
Monro, of Edinburgh. There are, however, two remark-
able exceptions to this account of the  British Anatomists.
The late Mr. Falconar, who wrote a dissertation on the
situation  and structure of  the spleen,  which contains
the sentiments  of  the late  truly respectable  Mr.  Hew-
son,* after stating that the organ was extremely vascular,
so that when injected it appeared like a mere congeries of
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
the cellular substance, by their round  figure and their
great regularity.

             • See Experimental Inquiries, vol. Ill,
   Vpl. II.                U 
 154            Questions relating to the
   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.
   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 vessicles, although de-
• See the London Philosophical Transactions for 1808. 
                Structure of the Spleen.            155
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 Hew-
son and Home among the British.
   The sentiments  of  physiologists respecting the func-
tions of the 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 Inquiries, vol. III.
         Dr. Rush. Medical Museum, vol. HI.
         Haller. Elementa Physiologic, torn. vi. pag. 414. 
15ti
                  CHAPTER VI.

OF THE URINARY ORGANS, AND THE GLANDULJE RENALES.

THE urinary organs consist of the Kidneys,  which are
sjtuated in the lumbar regions; ofthe 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  connection 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 of 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 advan-
tageously with them.

                     SECTION I.
              Ofthe 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-
milunar figure with three  sides, one of  which  is accom- 
Glandula Renales.
157
modated to the convexity of the kidney. Their color 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 color in adults, is yellowish in young sub-
jects, 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 princi-
pal 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 animals;
but their nature and functions are altogether unknown.

  • The cavity in these bodies has sometimes been sought for in vain
 Haller found it in sixteen cases out of nineteen, 
158
                    SECTION II.
            Of the Kidneys and Ureters.
   THE kidneys are two glandular bodies  which secrete
the urine. They are of a dull red  color, and their form
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 connec-
tion with the peritoneum.
   They are situated jn 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  lumbo-
rum muscles, and their position is oblique; the concave
edge presenting  inwards and forwards, the convex edge
backwards, and the  upper extremity approaching  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 glandulae  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 broad- 
                     The Kidneys.                 159
er and larger than the lower. The edge which is posterior
and external is regularly convex; the anterior edge is con-
cave; but the concave edge, or margin, is not very regu-
lar. In the middle it is  largely indented; in  this indenta-
tion is a deep fissure, which separates  the two broad sur-
faces 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 pro-
ceeds immediately from the aorta, nearly in a rectangular
direction. A vein, which opens into the vena cava, accom-
panies 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 are also anterior  to  the  arteries. At the great
fissure these vessels divide into several branches, 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 branches 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 denominated the  pelvis of the
kidney, and the tube a ureter: each of these  parts will
saon be  more particularly described.
   The substance of the kidney, as has been already said,
is uniform in its texture, and of  a reddish brown color.
 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 exterior
part, which is called cortical, is rather more pale in color
and softer in consistence than the  internal part.  It varies 
 160                 The Kidneys.
 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 between the two
 statements.
   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 papilla? 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 con-
 tinue their arborescent ramifications until they have arriv-
 ed very near the exterior surface. They are so uniformly
 distributed to the different parts of the organ, that when
 the bloodvessels are injected  with wax, and the substance
 ofthe kidney is removed from the injected matter, as is the
 case in corroded preparations, the injection exhibits accu-
 rately 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 ofthe
 gland, and are surrounded by membrane, which frequently
 contains adeps.
  There are commonly ten or twelve papillae in the  fissure
 of each kidney, but there are sometimes more and  some-
 times less than this number. These papillae are surrounded
by a membranous sac of a corresponding form; the  papil-
la being a cone, and the sac resembling the upper part of 
      Gortical and Tubular Portions ofthe Kidney.   161
a funnel.  The sac is therefore called an infundibulum, or
calyx. Sometimes there are two  papillae in each infundi-
bulum, 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 com-
municates, at its apex, with the pelvis ofthe kidney.
   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 ramifica-
tions 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 composed 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 termi-
nate on the surfaces of the papillae, in orifices large enough
to be seen  distinctly.  From these orifices urine  may be
  Vol. II.                X 
162  Nerves and Lymphatics. Codt of the Kidney.
forced out, by compressing the papillse. 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 fcetus, each lobe appears like
a distinct organ. Although in the adult kidney this struc-
ture has disappeared, the papilla? and the tubular part con-
nected with them are somewhat detached from each other,
in a manner corresponding to their original arrangement.
  The Nerves ofthe 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 peeled  off.
It is reflected inwards at the fissure ofthe 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 
          Course and Structure of the Ureters.       163
flatteued, and  between three and five lines in  diameter,
with some variations in this respect.
  The Ureters descend from the pelvis of the  kidney so
as 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 jts external and posterior part.
They first penetrate obliquely the muscular coat, and then
proceed between the muscular and internal coats, from
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 neighboring parts. Their internal coat is very vas-
cular, and is also very sensible of irritation. The passage 
164            Situation of the Bladder.
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 Ipladder 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 ofthe bladder is in a continued state of varia-
tion,  according to the quantity of urine secreted. When
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 immovably 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 lower part of  the rectum. 
             Muscular Coat ofthe Bladder.         165
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 connection of these
last mentioned parts is very different in the two sexes.
   The peritoneum is reflected at th  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 lower 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 abdominal
muscles, is without  a covering of peritoneum, being be-
low it.
  The bladder is composed of a coat consisting of  mus-
eular 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 perceptible
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 
166          Internal Coat of the Bladder.
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, might 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 to
distention, and recovers  its original  dimensions  very
easily.  From  its analogy to a similar  coat in the  intes-
tines, it is called the Nervous Coat.
   The Internal Coat of the bladder is of a light  color 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 surface.  '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 
                 Mucus of the Bladder.             167
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 cor-
respond 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 color, 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.
   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 by the irritation of
a calculus in the bladder, the urine is  rendered somewhat
viscid and white colored by the  mucus mixed with  it;
which, after  the 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

   • 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. 
 168             Orifice ofthe Urethra.
 twenty-four hours. The same circumstances occur, with-
 out the  irritation of calculus, in the disease called ca-
 tarrh us vesicae.*
   It  is probable that,  in healthy persons, a great deal
 of it  passes  off  unperceived,  being dissolved or  dif-
 fused 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 from
 every part of the surface; and it is a question that has not
 been  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 irregular oval,
although it was somewhat varied in different 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 ori-
 fice of the urethra is situated anteriorly  at the lowermost
part of the bladder. On the lower surface of the urethra,
at its commencement, and on the bottom of the bladder,
 immediately connected  with the urethra, is  situated the
 Prostate Gland, (to be hereafter described with the organs

  * In some cases tb'i3 mucus soon becomes putrid, and during the pu-
 trefactive process deposits a substance which appears to be calcareous. 
                  Neck ofthe Bladder.              169
of generation,) which is  a very firm body, that adheres
strongly both to the bladder and  urethra. This circum-
stance gives  particular firmness and  solidity to that part
of the bladder. It has also been observed, that the bladder
is attached firmly to the ossa pubis, at its neck, about the
origin ofthe  urethra. Each of these circumstances have an
effect upon the orifice of the urethra; and when the blad-
der is opened, and this orifice is examined from  within, it
appears to be kept open by the connection of the bladder
with the prostate, and has been very  justly 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  ofthe bottom ofthe bladder which is imme-
diately behind the triangular space, is rather lower  than
this space; and but a small portion of cellular membrane
exists between it and the rectum in males, and the vagina
in females.
   The upper part of the bladder is  connected with the
umbilicus by means of a ligament, which passes between

  • The late Mr. Lieutaud, and after him the French anatomists ofthe
present day, have described a small  tubercle at the lower and poste-
rior part of the orifice of the urethra, which  resembles the uvula  in
form. It has not been noticed here; and M. Boyer states, thut it is often
scarcely perceptible. He, however, makes  a remark which is very wor-
thy of attention, viz  that it is very subject to enlargement in ..hi peo-
ple, forming a  tumor which impedes the discharge of urine. Sabatier
has also made the same observation.
   Vol. II.                 Y 
170     Ligaments and Vessels of the Bladder.
the peritoneum and the abdominal muscles. This ligament
consists of three cords. One of these, which is in the mid-
dle, 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 arteries.* The middle cord
is of a light  color and fibrous structure; it is thickest at
the bladder, and gradually diminishes as it approaches
the umbilicus. In a few instances 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 con-
 tinue 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 re-
 ceives branches from several of them; viz. from the umbi-
lical 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 terminations in
 exhalents on the  surface of the  bladder are remarkably
numerous.
   The  veins  correspond with the arteries, but they are
 very numerous on the lower and lateral parts of the blad-

   • See the accounts of these parts in the description ofthe Abdomen
ofthe Foetus. 
                   General Observations.               171

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 than  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 abdomen,
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 ad-
      vantage after the structure of the urethra and the muscles con-
      nected 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 diseases
      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 constantly
      found in it, and many others that are occasionally in it, which
      are taken as aliment or medicine, and pass to the  bladder with
     little, if any, change. The odor ofthe rose leaf, the color of rhu-
     barb, &c. are occasionally perceived in urine. 
General Observations.
  The substances constantly found in urine are numerous. The
chemical account of the subject is so long, that it cannot be de-
tailed here; but the student ought to make himself acquainted
with it,  and he will read with great advantage, Johnson's His-
tory of \nimal  Chemistry, vol. 2d, page 363; and also Thomp-
son's Elements of Chemistry, page 333. 
173
                   CHAPTER  V.

        OF THE MALE ORGANS OF GENERATION.

 J HESE 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  I.
       Ofthe Testicles and their appendages.
  THE Testicles are two bodies of a flattened oval form.
Each of them has 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 contained 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

                     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 and
more delicate. The superior delicacy of this portion of the 
 174           Structure ofthe Scrotum.
 skin is evinced by the great irritation  produced by the
 application of stimulating substances, and the desquama-
 tion of the cuticle, which seems to be the effect of irrita-
 tion. 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 pro-
 ceeds 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 invests
 each testicle in such  a manner, that when they are with-
 drawn a cavity is left in it. It has long been observed, that
 no adipose matter is 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 substance was simply cellu-
 lar, and without 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 in this structure.
   After the testicles are removed, so as to leave the cel-
lular substance connected with the skin, if the scrotum be 
              Action ofthe Dartos Muscle.         175
inverted, and this substance examined in a strong light,
many fibres will appear superadded to the common cellu-
lar structure; and sometimes  their color  can  be distin-
guished to be red. It is  not  asserted that this will  be
uniformly the case; but certainly it has often been observe
ed in this way.
   The existence of an organ  which possesses the power
of contraction, within the skin of the scrotum and connect-
ed to it, is evinced by the corrugation which takes place
when the scrotum is suddenly  exposed to cold, after hav-
ing 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 poul-
tice from this part some days after the operation for the
cure of hydrops testis, by  incision; if the air ofthe cham-
ber be cool, a motion of the scrotum  will take place, almost
equal to the peristaltic movements 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 origin
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 ex-
cretory duct of the testicle, connected to each other  by 
 176 Cremaster Muscle. Bloodvessels ofthe Testicle.
 cellular substance, and covered by an expansion of mus-
 cular fibres which are derived from the lower edge of the
 internal  oblique  muscle of the  abdomen, and continue
 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 afterwards
 meets the vas deferens, and proceeds through the abdomi-
 nal ring to the 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 membranous parti-
 tions 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 ofthe spermatic vein are much larger than
 those of the artery: several of them proceed from the tes-
ticle 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 consi-
derable 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 
     Lymphatics and Nerves in the Spermatic Cord.   1 77
form one trunk,  which continues  upwards so as to unite
with the vena cava on 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-
ous, considering the size of  the organ. Six or eight, and
sometimes more, large trunks have been injected, running
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  tes-
ticle.  A small plexus, called the spermatic, is formed by
fibres from  the  renal plexus and  from the sympathetic
nerve. These fibres accompany the spermatic vessels, and
in all probability enter the body of the testis and the epi-
didymis. The spermatic cord and cremaster muscle re-
ceive  filaments from the second lumbar nerve.
   In  addition to these vessels, the Vas Deferens, which
is much firmer than either of them, is always to be distin-
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 abdominal ring,
and continues to the upper part of the external coat of
the testicle, which is a sac apparently containing that or-
gan, and upon this sac it is spread  out and terminates.

                 The Tunica Vaginalis.
  The External Coat of the testicle, which is commonly call-
ed the Tunica Vaginalis, is a complete sac which incloses
the testicle as the pericardium incloses the heart. It covers
  Vol. II.                 Z 
178              Coats ofthe Testicle.
the body ofthe testicle and epididymis, and adheres close-
ly to them. It is then reflected from them so as to form a
loose sac, which  appears 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  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 lubri-
cate  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 Albuginea.
Upon the upper and posterior part  of it is  the protube-
rant  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 ofthe testicle  is completely inclosed,
is firm and dense; and upon  this coat its particular  form
depends. It is of a whitish color, and has a smooth exter-
nal surface. It is thick as well as strong.  The epididymis 
        Form and Connections ofthe Epididymis.     179
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 vaginalis 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.

                   The Epididymis
   Differs in color 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 de-
tached from it. It has 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 epi-
didymis 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 adhere. 
180   Tubuli, Septa and Bloodvessels ofthe Testicle.

               The Body of the Testicle.
   When the tunica  albuginea is  cut through,  and the
substance of the testicle examined, it  appears  to con-
sist  of a soft  pulpy  substance  of a yellowish brown
color,  which is divided into  separate portions by  very
delicate  septa, attached to the internal surface of the
tunica albuginea at the posterior part ofthe testicle. After
maceration, by using a fine needle to detach them from the
cellular substance, these threads may be  drawn out to a
great length. In some animals they are larger than in the
human species; in them,  it is said, thev 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 Highmorianum, 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 into  the  body of the testicle
upon these septa, and are continued from tnem 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 di-
rect communication subsists between them, without the in- 
         Structure ofthe Testicle and Epididymis.    181
tervention 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 vet 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
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 Coni  Vaaculosi. 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, and finally becomes straight: 
 182         Diameter of the Vas Deferens.
 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
 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 upwards in the posterior part of the spermatic
 cord, and  continues  with it through the abdominal ring,

  * De Graff appears to have been the first anatomist who made much
 progress in the successful investigation ofthe structure ofthe 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 Literary and Physical
Essays of Edinburgh, and also in his Inaugural Thesis. Haller has like-
wise 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 testicle with mercury, injected by the vas
deferens. 
             Course of the Vas Deferens.          188
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 appear to
be nearly parallel. They proceed forward between the ve-
siculse seminales, which are two bodies irregularly con-
voluted,  that are placed in a converging position  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 termi-
nation  they enlarge in  diameter, and become somewhat
convoluted. At the posterior margin of  the prostate they
come in  contact with the anterior extremities of the vesi-
culae 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 Gallinaginis, soon to be
described.


                    SECTION II.
 Of the Vesicula Seminales and the Prostate Gland.
   THE  Vesicula Seminales are two bodies of a whitish
color, 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 
 184      Structure ofthe Vesicula Seminales.
 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 vesiculse 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.
   This convoluted  tube, composing the vesiculse semi-
 nales, terminates in a very short duct, which is nearly of
 the  same diameter with the  vas deferens, and this duct
joins 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- 
           Function of the Vesicula Seminales.       185
served, that a fluid passes in this  manner  much nore
readily from the vasa d-ferentia into the vesiculae -cmi-
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. Hunter 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 following 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.
   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 aptx anterior; its position is
oblique, between the rectum and the symphisis pubis. Qn
   Vol. II.                 2 A 
186            Prostate Gland. Penis.
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 schirrus rather more than the  ordinary texture
of glands.
   This gland receives small branches from the neighbor-
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.

                    SECTION III.
                    Ofthe  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 commencement,
form the bifurcated portions, and then unite to compose
the body of the organ; and a third  part, of a spongy tex-
ture, which is connected to these bodies where they unite
 to each other, on the under side, and continues attached to 
               Corpora Cavernosa Penis.           187
them during the whole extent of their union, terminating
in an expanded head which covers the anterior extremi-
ties 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 Urethra.
   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
ofthe 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
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- 
 188      Structure ofthe Corpora Cavernosa.
 gular cvlinders, 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 paced. 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
 of fibres, with their intervals, are so regularly arranged,
 that  they 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 their union, and continue through their whole
 extent, sending off branches in their  course: the tume-
scence and er. ction  of the penis  is unquestionably pro-
duct  d by the  blood which flows through these vessels into
the penis. 
             Cells ofthe Corpora Cavernosa.         189
   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 colored wax, injected by the artery, and the
animal substance is then destroyed by placing the  prepa-
ration 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;  »nd
therefore, if a pipe be  passed through the strong coat of
thi  penis, the whole of  them can be filled  from it  by the
ordinary process of injection.

                     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 invest-
ed  by a spongy structure, called the  corpus  spongiosum
urethra. It proceeds from the  neck  of the  bladder along
a  groove in  the upper part of the  prostate;  from  the
prostate it  continues between the crura of the penis until
their junction: it then occupies the great groove formed by

        * The late J. Hunter thought they were muscular. 
190     Corpus Spongiosum. Bulb. Glans Penis.
the corpora cavernosa on the lower side of the penis, and
continues to the orifice above mentioned. At a small dis-
tance from the prostate gland the spongy substance which
invests it commences, and  continues to its termination.
After this spongy substance has arrived at the termina-
tion of  the corpora  cavernosa, it expands and forms a
body of a particular  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 ofthe 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
longitudinal depression in the middle,  which  ts very su-
perficial. It consists entirely ofthe 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 
          Structure ofthe Corpus Spongiosum.      191
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 prominent 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 colored 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 ofthe 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
which are of considerable size. It  is extremely sensible, 
 192        Internal Surface ofthe Urethra.
 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  soon  becomes thick and
 large; anteriorly it gradually diminishes to a line, which
 is sometimes perceptible for a considerable distance  in
 the  urethra, in  a  straight  forward  direction.  In  the
 upper edge or top of this body is a grove,  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 183,
4), 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 dis-
tance before the caput gallinaginis are the openings of two
 ducts, one on each side, that lead  to small glandular bo-
 dies called Cowper's glands, which are situated 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
prostaie.  That portion  of the canal which is  between
this giand  and the bulb, without investment, and there-
fore called the membranous part,  is the smallest in dia-
meter. 
             Mucous Ducts of the Urethra.         193
   After it is invested with the spongy substance it has a
small enlargement, and then continues nearly of one size
until it arrives near the glans penis, when it again enlarges
and alters its form, being no longer cylindrical but flatten-
ed. 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 color; but bloodvessels are
very perceptible in it. When it is relaxed, it appears to be
thrown into longitudinal wrinkles; but it admits of consi-
derable extension, being somewhat elastic: when extend-
ed, its  surface appears smooth, as if it were covered 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 backwards 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, although 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 dis-
charge 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
unperceived.
   The surface of the urethra is endued with great sensi-
bility, and is therefore  liable to great irritation from con
   Vol. II.                2 B 
194       Contractile Power ofthe Urethra.
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 into
the urethra for a considerable distance, if it cannot  pro-
ceed the whole way, it sometimes  happens that the instru-
ment will be discharged by a steady  uniform motion,
which seems to proceed from  a  progressive contraction
of the urethra, beginning very low down.  At particular
times, after the urethra has been much irritated, 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 elasticity which  was no-
ticed before.
   Upon the two crura of the penis, or the beginning of
the corpora cavernosa, are fixed the muscles called Erec-
tores Penis, which are described Vol. I. page 204. 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, (described in the page next
to the one above mentioned) which has the effect of driving
forwards any fluid contained in the cavity of the urethra,
and also of giving the same direction to the blood in that
part of the corpus spongiosum. There is also the Trans-
versa Perinei on each side, that passes transversely from
the tuberosity of the ischium to the bulb of the  urethra.
Finally the lower part of the sphincter ani muscle, which
is nearly elliptical 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 
                Integuments ofthe Penis.            195
concealed,  particularly  by  the  anterior  point of  the
sphincter ani. When the sphincter ani is dissected away
from its anterior connections, and the cellular and adipose
substance, which is sometimes very abundant, is also re-
moved, the lower surface of the  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  ca-
vity 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 li-
gamentous 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 described, 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.
  • The natural situation of the membranous part of the urethra, and
ofthe prostate gland, as well as their relative position with respect to
the sphincter ani, rectum, &c.  can be best studied by a lateral view of
the contents ofthe pelvis; which is to be obtained by removing care-
fully one ofthe ossa innominata, and dissecting the parts which were
inclosed by it 
196                 The Prepuce.
  Around the corona of the glans, especially on its upper
part, 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 continues from the glans
upon the body ofthe 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  ligamentous 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
connected  to the penis, has commonly more length than
that organ, even in its extended state. In consequence of
this greater length, and of its adhering firmly around the
corona 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 ofthe 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 distance 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 longitu-
dinal in its direction, that commences at the orifice of the
urethra, and extends backwards, on the lower surface of
the  penis.  It is unvarying in its position, and  is called
the Frenum.
    It  is a  general observation, that adeps is not found in
the cellular substance which connects the skin to the bodv 
        Bloodvessels and Absorbents ofthe Penis.    197
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, becomes
inspissated, and  acquires a caseous consistence and color,
as well as a peculiar odor.  It sometimes 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 assert-
ed, that branches of the middle hemorrhoidal 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 communicate
more or less with the  plexus of veins on the  lower and
lateral  parts of the bladder. There 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 urethra;  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 
 198         Nerves.—General Observations.
 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 inte-
 guments 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 ori-
 ginate from the interior parts of the penis, accompany the
 bloodvessels, and terminate in the plexus of lymphatics in
 the pelvis.
   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-
      cles and bloodvessels  ofthe 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. 
General Observations.
199
  taput xviii. Haller has also considered it, and stated the
  opinions of several anatomists; in his Elementa Physi-
  ologiae, torn. vii. page 555.
The manner in which the urine is confined in the blad-
  der 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  probable that these parts act like
  a sphincter. The late J. Hunter, who paid great atten-
  tion to the functions of these organs, was  very decided
  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 respect-
  ing the manner in which urine  is discharged from the
  bladder, in  his  Treatise  on the Venereal Disease,
  part III. chapter IX.
Mr. Hunter also long since asserted, that the  vascular con-
  voluted 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 declaration of Hunter, respecting the vascular con-
  volutions 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
  ramifications 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, &c. and in them all
  these communicating branches can be distinguished
  from  those which extend the whole length ofthe penis.
The corpus  spongiosum urethrae, according to M. Cu-
  vier,  is constructed in a similar manner. From these
  facts  he is induced to believe  that this  structure per-
  vades the whole class of mammalia. 
200
                  CHAPTER VI.

       OF THE FEMALE ORGANS OF GENERATION
THE 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  uterus 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.

       Ofthe External Parts of Generation.
   THE  adipose  membrane, immediately anterior to  the
symphysis pubis,  and on each side of it, forms  a conside-
rable prominence  in females, which, at the age of puberty,
is covered with hair, as in males.  This prominence is  de-
nominated the Mons Veneris. 
                Labia Externa.—Clitoris.           201
   The exterior orifice commences  immediately below
 this. On each side of this orifice is a prominence continued
 from the mons veneris, which is largest above, and gradu-
 ally diminishes as it descends.  These prominences have
 Some hair upon them. They are  called the Labia Externa.
 Their junction below is denominated the Fourchette. The
 space between the place of their junction and the anus is
 rather more than an inch in extent, and is denominated
 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 re-
 semblance 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  cura 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 propor-
tion. The extremity of this organ,  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 ofthe eorpora cavernosa of the.penis,
or the corpus spongiosum ofthe  urethra.  It appears con-
structed  for a similar distention, and is indued with the
   Vol. II.                2 C 
202        Nympha.—Orifice of Urethra.
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.
  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 denomina-
ted the Nympha.
  The Nympha extend from the clitoris downwards near-
ly as far as 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  internal 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 in-
stances 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 it. 
                  Hymen.—Vagina.              203
  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 ofthe membrane, which forms the surface con-
tiguous to it. Sometimes it is circular, with an aperture 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  menstrual
evacuation. It is generally ruptured in the first intercourse
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 tu-
bercles are called Caruncula Myrtiformes.


                   SECTION II.
                  Ofthe Vagina.
  THE canal of the vagina, commencing at the hymen and
the orifice of the urethra, is rather more narrow at its be-
ginning than it is further inward.  From  this place it ev
tends  backwards and  upwards, and partakes  in a small
degree of the  curve  of the rectum: while the bladder,
whieh 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 papillae; and at the anterior extremity of the
vagina it forms a great number of rugae, which are arran- 
204    Corpora Cavernosa.—Sphincter Vagina.
ged in a transverse direction, both on the part ofthe vagina
connected to the bladder, and on that which is connected
to the rectum, while the lateral parts of the vagina 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 ru-
gae on the part next to the bladder are the strongest.
   This arrangement of the surface of the vagina does not
extend beyond the external half of the canal: on the inter-
nal half part, or that nearest the uterus, the surface is
smooth.
   The rugae are considerably diminished m 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 completely
investigated:  it is of a lightish colour, and has some re-
semblance to the texture of the body of the uterus. It is
very vascular, and appears to  be of a fibrous structure. It
may be very much distended, and seems to have a con-
tractile  power*
   At the anterior extremity of the vagina, on each side of
it, ;there is, superadded to this, a  cellular or vascular sub-
stance,  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 commence near
the body of the clitoris, and  extend downwards on each
side of the vagina. They have been called Plexus Rete-
formis, and Corpora Cavernosa Vagina, and are supposed
to be occasionally distended with blood, like the clitoris
and penis. 
                Unimpregnated Uterus.            205
  These corpora cavernosa are covered by muscular fibres,
which pass over them on each side from the sphincter 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-
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.
  Ofthe 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 bodv
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. 
206           Ligaments ofthe Uterus.
   It is generally larger than this  in women who have
lately had children.
   The uterus is situated in the pelvis between the bladder
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, 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 ofthe uterus, being inclosed by  a process ofthe
ligament or septum. Above them, in the upper edge of the
septum, are the Fallopian Tubes, which are ducts that com-
mence 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
surface  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 rec-
tum posteriorly, and two more to the bladder anteriorly:
these are  called the Anterior and Posterior Ligaments of
the Uterus.
   Two 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 
          Structure and Cavity ofthe Uterus.       207
ligaments are also invested by the peritoneum. They pass
through the rings and soon terminate.
   In the body of the uterus is *. cavity which approaches
to the triangular form;  and from which a canal proceeds
"ihrough its neck. This cavity ••- 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.
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
connected to the substance of the uterus that some anato-
mists have supposed it  was merely the internal surface of
that substance, but this  opinion is now generally aban-
doned. 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 po-
sition, 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 
208        Cavity ofthe Neck ofthe Uterus.
of the fallopian tubes, which are of such sire  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
angles 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,
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 commencement
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 becomes
enlarged in the progress of pregnancy, this canal is gradu-
ally 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 that it divides the convex surface of 
           Structure ofthe Fallopian Tjubes.        209
the neck into two portions, which are called the Lips.  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 tjneae on the pos-
terior 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 ligaments, from
the upper angles ofthe uterus, in a transverse direction, to
some distance from the uterus, when they form an angle,
and take a direction downwards towards the ovaries.
   They are formed, for a considerable part of their extent,
by a substance which resembles that of which the uterus
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 color. 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 re-
spects the axis of the tube; and the different fringed pro-
cesses are not all of the same length; but the  longest are
in the middle, and the others  regularly diminish on each
   Vol. II.               2  D 
210     Situation and Structure ofthe Ovaries.
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 color 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 ofthe broad
ligament to the abdominal rings, through which they pass;
and then their fibres and vessels are 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-
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, but 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 ligament.
   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 
         Corpora, Lutea.  Arteries of the Uterus.     211
 many bloodvessels.  In virgins of mature age it contains
 from ten to twenty vesicles, formed of a delicate mem-
 brane, filled with a transparent  coagulable fluid.  Some
 of these vesicles are situated so near to the surface of the
 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
 some time after delivery, but it gradually vanishes. The
 cicatrization continues during life.
  In many cases these cicatrices correspond with the num-
 ber 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 hypogastric
arteries. 
 212              Veins of the Uterus.
   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 ofthe hypogas-
 tric arteries. There are also branches of these arteries in the
 round ligaments, which accompany them to their termina-
 tion 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 laminae 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;
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 
         Lymphatics and Nerves ofthe Uterus.      213
branches are  greatly enlarged indeed during pregnancy;
and it is said that they are enlarged in 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 ofthe uterus; from which two
or more uterine veins proceed in the course of the artery,
and join the hypogastric. These veins also are 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.

                     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.

            Ofthe 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
ureters is rather lower in males than in females. The bot- 
214
Urethra.—Gravid Uterus.
torn ofthe 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 tumour, which
compresses 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 the erect position, it is nearly
horizontal; but is slightly curved, with its convexity down-
wards.  It is immediately above the vagina, and it passes
below the body of the clitoris. The external orifice 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 longitudinal
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 been
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 a  prostate. It
is capable  of great artificial dilatation.

 Ofthe Changes induced in the Uterus in the progress of
                     Pregnancy.
   The alteration which takes place in the size ofthe ute-
rus during pregnancy is truly great.  About the conclusion

  * It has however been asserted that they are also less liable to cal-
culi in tlie kidneys. 
         Gradual Change in the Gravid Uterus.     215
of that period, instead ofthe small body above described,
which is almost solid, the uterus forms an immense sac,
which extends from the termination of the vagina in the
pelvis, into the epigastric region; and from one side ofthe
abdomen to the other; preserving, however, an ovoid figure.
  This change is so gradual at first, that the  uterus does
not extend beyond the cavity of the pelvis 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, and 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
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 substance; 
216
General Observations.
 nor are the arteries much less convoluted than before preg-
 nancy, as might have been expected.  They  are  greatly
 enlarged in diameter, and the orifices of the exhalent ves-
 sels on the internal  surface of the  uterus are much more
 perceptible.
   The veins are much more enlarged  than the arteries,
 and in some places  appear more than half an inch in dia-
 meter. They are not regularly cylindrical, but rather flat.
 They anastomose so as to form an  irregular net work.
   The uterus appears  much  more fibrous and muscular
in the gravid than in the unimpregnated state.  The con-
tractile power of the gravid uterus  is not only proved by
the expulsion of its contents, but also by very vigorous con-
tractions, which are occasionally observed by accoucheurs.

    Although the general effects which result from the par-
      ticular conditions of the uterus in pregnancy, 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, which is pub-
      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
     po hair on the pubes, nor were  there any indications of
     puberty in mind or body.  She never mensiruated. At
     the age of twenty-nine she died of  a complaint in the
     breast, attended with convulsions.  The uterus and oc 
          Peculiarity ofthe Female Hottentots.       217

      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 ofthe 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
      t6 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 distensi-
      ble skin, free  from hair, which  is occasionally corru-
      gated like the scrotum, and  is rather more florid than
      the ordinary cutis.*

               The Abdomen ofthe Fatus.
   The difference between the fcetus and the adult, in the
cavity of the abdomen, is very conspicuous at the first
view.

  * This paper has not yet  been published by the Institute, but it is
.eferred to by M. Cuvier in  his Lecons d'Anatomie Comparee, vol. v.
page 124.—Messrs Peron and Lesueur were naturalists who accom-
panied captain Baudin in his voyage  of discovery.
   Vol. II.                    2  E 
218   Peculiarities in the Abdomen ofthe Fatus.
  The Liver in the fcetus 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 urachus of the fcetus 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 the
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 the foetus
than in the  adult.
  The Great Intestine does not extend sufficiently far, be-
yond the insertion of the ileon, to form the caecum com-
pletely.
  The Glandula Renales are much larger in proportion in
the fcetus than  in  the adult.  The color of the fluid they
contain is more florid.
  The Kidneys are lobulated.
  The Testicles in the fcetus are  found above the pelvis,
in the lumbar region, behind the peritoneum,  until two
months before birth.  Thus situated, their bloodvessels and
nerves proceed from sources which are near them; but the 
          Descent ofthe Testicle in the Fatus.      219
vas deferens, being connected to the vesiculae seminales by
one extremity, is necessarily in a very different situation
from what it is in the adult: it proceeds from the testicle
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-
heres  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
scrotum.  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 testicle
has arrived near the abdominal ring, a portion of the pe-
ritoneum is  protruded a little way before it into the scro-
tum; forming a cavity like the finger of a glove.  The tes-
ticle 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 testi-
cle are also exterior to it.
   The cavity formed in the scrotum, by this  process of the
peritoneum, necessarily communicates with the  cavity of 
220
Umbilical Vessels.
the  abdomen  at  its formation;  but very soon after the
testicle has descended into the scrotum, the upper part of
tb is cavity is closed up, while the lower part ofthe process
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 fcetus 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 pass
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 con-

  * These interesting circumstances respecting the original situation
of the testicle, and its descent into the scrotum, were discovered and
elucidated by  Haller, 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  testicles
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 fatus, in the "  Observations on cer-
tain parts of the Animal Economy," hy John Hunter 
Ductus Venosus.
221
verted into ligaments. They are exterior to the peritoneum,
and contained in a duplicature of it.
  A  vein also called the Umbilical, which is much larger
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 Duc-
tus, or Canalis  Venosus; to distinguish it from the duct
which pksses from the pulmonary artery to the aorta, and
is called Ductus, or Canalis Arteriosus. This venous duct
carries some ofthe blood ofthe 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, although
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 vena cava. 
 222     Object ofthe Circulation in the Placenta.
   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 from each side of it, and the ductus venosus like
 a  branch continuing in the direction of the main trunk
 ofthe 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 sinus, 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 minute
branches of the umbilical vein; and it is probable that the
whole blood carried to the placenta by these arteries, re-
turns by  the umbilical vein to the  foetus.
   It is clearly proved by the effects of pressure on the
umbilical cord, in cases of delivery by the feet, as well as by
other similar circumstances, that this circulation cannot be
suspended for any length of time  without destroying the
life of the fcetus. From these circumstances, and  from the
florid color which the blood acquires by circulating in the 
         Object of the Circulation in the Placenta.     223

placenta, it seems probable that the object of the circula-
tion  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 artery arises
from  the mesenteric, and the vein is united to the mesenteric branch
ofthe vena portarum. It is probable that these vessels commonly exist
no longer than the vesicle, viz. about four months; but they have been
seen  by Haller and  Chaussier at the termination of pregnancy. They
are called Omphalo Mesenteric vessels.  The vesicle is denominated the
Umbilical Vesicle.
  This inexplicable structure is delineated in Hunter's Anatomy ofthe
Gravid Uterus, plate xxxiii. figures v. and vi.; in the Academical Anno-
tations of Albinus, first book, plate i. figure xii.; and also in the Icones
Embryonum Humanorum of Soemmering, figure ii. 
       SYSTEM OF ANATOMY.


                  PART IX.


             OF THE BLOODVESSELS.

 1 HE 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 ofthe 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  Veins. 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 
              The Bloodvessels in general.          225
vessels to their branches.  One  of  these great arteries,
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 the 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 cavae 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.
  Vol. II.               2 F 
226          The Bloodvessels in general.
   It is also certain, that  the blood is forced from the
heart into the arteries, by the coniraction  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 vvhich is thus thrown into them: but
their action appears to depend upon causes of a complex
nature. 
227
                   CHAPTER I.

 OP THE GENERAL STRUCTURE AND ARRANGEMENT OF .
                 THE BLOODVESSELS.

                     SECTION I.

                   Ofthe Arteries.

 JL HE 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 
228           Structure ofthe Arteries.
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
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, Elasti-
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 ofthe 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, vvhich
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 
               Structure of the Arteries.           229
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
laminae, which  have been considered as different coats of
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 lamina?, 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 graduallv increases
in proportion as the artery diminishes in size. He however 
230  Question respecting the muscularity of Arteries.
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 ofthe arteries is elastic, and in that respect differ-
ent from muscular substance,  the  reasons for doubting
must be increased.
   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 discussed in his AnatomieGenerate—System Vasculaire
a  Sang Rouge,  article  Troisieme, &c.  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,! ^^ *hey
have been made to contract by  the application of mecha-

  * Treatise on the Blood, &c. Vol I. p 113. Bradford's edition.
   | See Soemmering on the Structure of the Huidsji  Body, Vol. IV.
German edition.  Dr. Jones on the Process employed  by Nature for
suppressing Haemorrhage, &c. 
        Proofs ofthe Irritability ofthe Arteries.    231
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
  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 ofthe 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.

   •j- 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 pulsi-.tion
ofthe large arteries.                    ^ 
 232     Proofs ofthe Irritability ofthe Arteries.
   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 ofthe 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
 would through an inanimate elastic tube,  in  consequence
 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. 
          General Observations on the Arteries.      233
   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
entire.
   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.
   Arteries appear to  have a  cylindrical form,  for no
diminution 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 by the trunk.
   The transverse section of an artery is circular.
   There are no valves in the arteries, except those of the
orifices ofthe aorta and the pulmonary artery, at the heart.
The valves of the pulmonary artery have been described in
the 35th page of this volume, and those of the aorta have
an exact resemblance to them, but are rather larger.
   Vol. II.                2 G 
234      General Observations on the Arteries.
  The course  of the  arteries throughout  the  body is
obviously 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 enlargement,
as the  cheeks, they often meander; and, therefore, their
length may be increased by straightening, without stretch-
ing them.
  Their course appears sometimes to have been calculated
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
generally 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. Sometimes,
a transverse  branch runs from one  to  the  other, so as
to form a right angle with each.  In other cases, the two
anastomosing branches form  an  arch,  or portion of a
circle, from which many branches go off.
  By successive ramifications, arteries gradually diminish
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 ofthe 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. 
           General Observations on the Veins.       235
   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 arteries.


                    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
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 
236         Coats of Veins.  Valves of Veins.
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.
   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, they form a septum
in the cylindrical cavity of the vessel. The septum, thus
composed, is concave towards the heart. 
            Colour ofthe Blood in the Veins.        237
  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 ofthe 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. 
238
                   CHAPTER II.

  A PARTICULAR ACCOUNT OF THE DISTRIBUTION OF THE
                      ARTERIES.

                     SECTION I.

                 Of the AORTA,
    Or the Great Trunk of the Arterial System.

 W HEN the heart is in its natural position, the right ven-
tricle 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 position
before its course alters, for it then proceeds obliquely back-
wards, 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 body, 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 middle
of its length, and the left rib near the head.  In consequence
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 column. 
 Situation ofthe Aorta in the Thorax and Abdomen. 239
  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 division:
this ligament was the Canalis Arteriosus in the foetus.
  As the  AORTA proceeds down the spine, it is situated
between the two laminae of the mediastinum, and in con-
tact 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 passage 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, vvhich form an acute
angle with each other. These are denominated the COM-
MON, or PRIMITIVE ILIAC Arteries.
  From the AORTA in this course are sent off the arteries
which are distributed to all the parts of the body for their
nourishment and animation.
  From the curve proceed the 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 o!
the pelvis receive some branches from the internal iliac arteries. 
240  Origin ofthe Subclavian and Carotid Arteries.
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  ofthe
                     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. 58.
   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 with 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. 
      Situation ofthe Common Carotid Arteries.    241
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 1N-
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 ofthe thyroid cartilage, when they divide
into the INTERNAL and EXTERNAL CAROTIDS.
  These arteries are at first very near each other, and
rather in front  ofthe trachea; they gradually diverge and
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 mas-
toidei, 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.
  Vol. II.             2 H 
 242            General Account of the
   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 deepseated; 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 regarded
 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; tiz.  to the upper 
External Carotid and its Branches.      243
part of the neck, to the parts within the lower jaw, and to
the cheeks and lips. These are denominated, the superior
thyroid, the sublingual, and the facial. It then sends
off to  the back of the head one which is called the occipi-
tal;  and, as it proceeds upwards near the condyle of the
lower jaw, another which passes internally, behind the jaw,
to the deepseated parts in that direction. After this, it forms
the temporal artery, which supplies the forehead and cen-
tral parts ofthe cranium. Besides these larger branches, the
external carotid sends off two which are smaller; one from
near the origin of the sublingual 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 there-
fore called posterior auris.
   These arteries are distributed in the following manner.

          l.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 cartilages,
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 oppo-
site side. 
244
Branches ofthe External Carotid.
       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 up-
 wards 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 contiguous
 to the tongue. It also sends off a branch which penetrates
 to the back ofthe tongue, which is called, from its situation,
 Dorsalis Lingua. At the anterior margin ofthe 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 glossus 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.  Before  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-hyoideus, the an-
 terior 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 ofthe mas-
 seter  muscle, and is so superficial that its pulsations can
 be readily perceived. After this turn, its course is obliquely 
           Branches of the External Carotid.       245
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 anastomoses
freely with its fellow on the opposite side. These anasto-
moses  are  frequently so considerable that the arteries 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 tortuous 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 ofthe eye and the forehead.

            4. The inferior  pharyngeal
Is a very  small artery; it arises  posteriorly from  the
external carotid, opposite to the  origin of the sublingual, 
 246      Branches ofthe External Carotid.
 and passes upwards to the basis of the cranium.  In this
 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 small 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
ofthe digastric muscle; it lies very near to the base ofthe
mastoid process, and under the muscles which are inserted
into it. After emerging from these muscles, it runs super-
ficially upon the occiput, dividing into branches which ex-
tend to those of the temporal artery.
   The occipital artery sends off branches to  the
muscles which are  contiguous to it, and to  the glands
ofthe neck.
  It also gives off the following branches:  One called the
Meningeal, which passes  through the  posterior foramen
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. 
           Branches ofthe External Carotid.        247
  The artery next to be described, is sometimes sent off
by the occipital artery.

   6. The posterior auricular, or stylo mastoid
                       ARTERY,
When it arises  from  the external carotid, comes off
posteriorly 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 ascends, in a curved direction, and terminates behind
the ear.
  In this course it sends off small branches to  the parotid
gland,  and to the digastric and sterno  mastoid muscles.
Sometimes a distinct branch, which is particularly visible
in children, passes through an aperture in the  meatus au-
ditorius 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 ofthe dura mater. When it has arrived behind
the ear,  the Posterior Auricular Artery terminates  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 ofthe condyloid process

  *  The general situation of this artery, and the distribution of several
of its most important branches, cannot be understood without a know-
ledge of the bones through which they pass. The student of surgery 
248        The Internal Maxillary Artery.
of the lower jaw, and extends to  the bottom of the  zy-
gomatic  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 Me-
ningeal, 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 hia-
tus 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

will therefore derive benefit from a re-examination of these bones, and
ofthe zygomatic fossa, &c. when he  studies this artery.  (See Vol. I.
page 64.)—He ought  to be well acquainted with this subject, if he
should undertake the management of necrosis of the jaw bones; or of
those fungous tumours, vvhich sometimes originate in the antrum
maxillare; as well as of several other complaints. 
             The Internal Afyxiifary AtHfy*        249
junction of the squamous and petfons  portions of the
temporal peine.
   p.  The  next branch sent off by the internal maxillary
leaves it about an inch from its origin, and is called the
Inferior Maxillary. Jt passes between th.e internal ptery-
goid  muscle and the hone-* aqd 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 pf the j^w, ^nd
the artery  in its progress along it spnds  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  vessels on the chin,
•jvhile another  branch passes forward and supplies the ca-
pine 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
$ase, 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, whicfy
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 tem-
poral muscle;  but the interior  br-ancji send? a small twig
 into  the orbit pf the eye,
   f. 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 anterior
 £eep temporal. They are g?flSrally -small,  and, tftf&n, irre-
 gular.
   Vol. II,               8 \ 
250        The Internal Maxillary Artery:
  G. An artery, particularly  appropriated to the cheek,
perforates the buccinator muscle from within outwards,
and generally terminates on the buccinator, the zygomati-
cs major and the muscles of the lips.  This Artery ofthe
Cheek is very irregular  in its origin,  sometimes arising
from the  internal maxillary,  sometimes  from the  deep
temporal,  and sometimes from the suborbitary, or  from
the alveolar artery, to be immediately described.
  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 ofthe 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 of 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 pe-
riosteum,  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 canine and
incisor teeth.
  j. The Palato Maxillary, or Superior Palatine Artery,
arises also in the zygomatic fossa, and, descending behind
the upper  maxillary bone, enters the posterior palatine ca-
nal. It generally forms two branches, the largest of which
advances  forward, supplying the palate and gums, and 
     Its Termination in the Nose. Temporal Artery.  251
finally sends a twig through the foramen incisivum 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 pala-
tine 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 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 ex-
ternal side of the  nose; each of  these branches ramifies
very minutely upon the Schneiderian membrane and its
processes in the different sinuses, and also in the ethmoidal
cells,

              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 passing 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
interior and posterior. 
252      Temporal Artery. Internal Carotid.
   Before this division the temporal artery sends off seve-
ral branches of very different sizes.
   One, which is considerable in size, and called the Transs
verse Facial Branch, advances forwards across the neck of
the condyle of the lower jaw, and giving small branches tb
the masseter, runs parallel to the parotid duct, ahd belotf
it. This branch is spent upon the muscles ofthe face, and
anastomoses ^rith the other vessels of that part.
   The temporal gives off small branches to the parotid
gland and to the articulation df the  jaW.  From the last
mentioned branch small twijgs j>aas to the ear, one of which
enters the cavity of the tympanum  by the glenoid fissure.
   While this artery is on a line with the zygoma, it sends
oiiFa branch called the middle temporal artery, which pene-
trates the aponeurosis of the temporal muscle, ahd rami-
fies under it upon the muscle in an anterior direction.
   The two great branches oJF 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;
ftnd 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. 
           Curvatures ofthe Internal Carotid.       253
   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
itfe separation from the external carotid, when it protrudes
outwards so much as to be exterior to that vessel; after
this, it ascends to the carotid canal, and in its course is in
Gontact, or very near the par vagum and intercostal nerves.
   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 di-
rection 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 momen-
tum of the blood must be impressed  upon the cranium.
   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 retain-
ed after leaving the bone.
   The object of these various flexures ofthe internal caro-
tid appears to be  analogous  to that  of  the Rete Mirabile
in certain quadrupeds, which is formed by the division of 
254              Ophthalmic Artery:
this artery  into many small branches, that reunite again,
without producing any other effect than the diminution of
the momentum of the blood.
   During its course from  the place of bifurcation to its
entrance into the carotid canal, the internal carotid artery
very rarely sends off any branches. In the canal it gives
off a small twig which enters the cavity of the tympanum;
and sometimes a second  which unites with the Pterygoid
branch of the internal maxillary.
   As  it goes by  the sella  tardea,  it passes through the
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 ofthe dura mater
which is connected with  the posterior clinoid process, and
the cuneiform process of the occipital bone.  It likewise
giv;s  branches to several of the nerves which are  con-
tiguous, and to the pituitary gland.
   The anterior artery also gives branches to the contigu-
ous 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. 
             Distribution of its Branches.         255
  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 ophthalmic
arrives within the orbit, and passes above the abductor
muscle to the lachrymal gland, where  it terminates, send-
ing 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
which  penetrates into the center of the optic nerve, and
passing with it into the eye is spread upon the internal sur-
face of the retina. Here  it appears to terminate in  the
adult; but in the foetus ;t 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 ofthe eye, vol. i. p. 353.)
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 palpebral, the levator
oculi, obliquus  superior,  &c; but these parts  are often 
 256       Branches, of the Ophthalmic Artery.
 supplied by the  branches above mentioned. The supra
 orbitar so 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 lower
 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
 of the ethmoid by the foramina of the  cribriform plate
 of that bone, and  sends a small branch to the Schneiderian
 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 ofthe Palpebra are called Superior and In-
ferior; 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 carun-
 cula lachrymalis, and the parts connected with the cartilage 
     Internal Carotid. Middle Artery of the Brain. 257
of the under eyelid, and unites with the lachrymal artery
near the external canthus, forming an arch called the Infe-
rior 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 lachry-
mal sac, it passes down the side of the nose and anastomo-
ses  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
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 anterior
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.
  Vol. II.               2 K 
258           Position ofthe Right and
   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 arteria
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
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. 
                Left Subclavian arteries.           259
  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 ofthe LEFT SUBCLAVIAN™ somewhat
different from  that ofthe right. Its origin is posterior, and,
therefore, the direction of the cord of its curve is  more
immediately lateral. The curve or arch is also smaller. The
situation of the two subclavians  as  relative to the con-
tiguous 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 ofthe cervical vertebrae, and
are inserted into the first rib, one before the other,  so as
to leave a considerable space between them. The subclavian
arteries pass through this space, and  before they arrive at
it,  but  when  they are very near the  above mentioned
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.
  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- 
260    Course and Distribution of the Inferior
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 almost
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 artery, 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
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 
           Thyroid and the Vertebral Arteries.       261
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 consi-
derable curve, the convexity of which has a lateral and
external aspect. After passing the transverse processes 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
cuneiform process ofthe 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
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 contiguous
parts,  and also upon the fourth ventricle and the Plexus
Choroides of that cavity. They are called the Posterior or
Inferior Arteries ofthe 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. 
252          Superior Intercostal Artery.
  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 call-
ed the arteria communicans, which passes directly for-
ward, and communicates with the internal carotid, thus
forming the arrangement, which is called the Circle  of
Willis.* After sending  off these arteries, they continue
their lateral direction, and are distributed principally to
the posterior parts of the  cerebrum. These terminating
branches ofthe basilar artery are called the Posterior
Arteries ofthe Cerebrum.

          The superior intercostal Artery
Arises  from the upper  part of the Subclavian, after the
Vertebral and Thyroidarteries, 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

  *  The arteria communicans is also considered as a branch of the
Internal Carotid. The arrangement here alluded to is very remarkable.
As the branches which pass off laterally from the single trunk ofthe
Basilar Artery unite to the Internal Carotids,  and the Internal  Carotids
are  united to each other, there is  an uninterrupted continuation 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 con-
nexion blood will pass from any one of the  four arteries of the brain
to all the others. 
          Arteries of the lower part of the Neck.      263
upon the contiguous  muscles, &c,  on the back  of the
thorax. The intercostal artery  also sends a branch
upwards to the deep seated parts ofthe 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 arteries arise from
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.*
  The Superior Scapular most cwmmonly arises  with
some  other artery, and  very  often from  the  Inferior
Thyroid. It runs transversely outwards, within and above

  * Haller paid great attention to the arterial system, and made many
dissections, with a view to engraving's of it, which he published with
descriptions, in folio fasciculi.
  These fasciculi have been collected, and, with some other engrav-
ings, form a large volume, entitled ICONES ANATOMICAE, 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. 
264       Branches that go off in the Axilla.
the clavicle, and passing through the notch in the upper
costa of the 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 scapula
and contiguous to it; and
  3d. To the parts which are near the upper extremity of
the os humeri.

                  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
THORACIC.E, MAMMARL* EXTERNA, &C. 
           Branches that go off in the Axilla.       265
  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 mentioned,
and  sometimes from  the Acromialis.  It often extends
downwards as low as the  sixth rib, and sends branches to
the anterior  part of the thorax,  to the mamma, and  the
Other contiguous parts. Many  ofthe small branches of this
artery  anastomose very freely with those of the internal
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 scapular, the common
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
  Vol. II.                2  L 
266       Branches that go off in the Axilla.
the bone, to be distributed  to the  infra spinatus  and
the contiguous muscles, which  is  called the Dorsalis
Scapula. The main trunk then inclines to the subscapularis
muscle, 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 Circumflexa.  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
muscles.
  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
deltoides.  It is distributed to the muscles 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. 
            Situation of the Humeral Artery.        26-*7
   The great artery of the arm proceeds from the axilla to
 the elbow; and,during this course, is generally denominated

               The HUMERAL Artery.*
 Its direction is influenced by the position ofthe os humeri.
 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 radial side of the
 fore arm, but soon after it passes across the joint ofthe el-
 bow, it divides into two branches: one which preserves, for
 some distance, the direction ofthe Main  Trunk, is called
 the  radial artery:  the other, which  inclines obliquely
 downwards and towards  the ulna, is the common trunk
 ofthe ulnar and interosseal 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 passing
 between the heads ofthe triceps extensor muscle, proceeds
 downwards under  that muscle, in a spiral direction, to-
 wards the external or radial condyle.  It  sends  several
 branches to the triceps and  the contiguous muscles, and
 one considerable branch, which  is generally  called the
 Profunda Minor, to the parts contiguous to the internal
* It is also called Brachial Artery by several writers. 
268       Branches ofthe Humeral Artery.
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 are 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 verv
irregular.
  The two great ramifications of the HUMERAL artery
on  the fore arm  have very different directions.  The
radial  artery preserving the course of the main trunk
while the common trunk ofthe ulnar and interosseal

  * 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 and Ramifications ofthe Radial Artery. 269
projects from it in a direction downwards and towards
the ulna, passing under the pronator teres, &c.

                 The radial Artery,
Passing over the pronator teres muscle, proceeds between
the supinator radii  longus and the flexor carpi radialis,
very near to the lower end ofthe radius, without changing
its direction materially, being deep seated above and su-
perficial below; it then alters its course, and, passing under
the tendons of the  extensors of the thumb,  to the back
part of the radius, it continues between the metacarpal
bones ofthe thumb and ofthe 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 ofthe 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 which
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  artery 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.
   The  three branches into which the  radial  arterv 
270  Origin ofthe Ulnar and Interosseal Arteries.
divides between the  metacarpal bones of the thumb and
index are, 1st. a branch to the external side ofthe index;
2dly, a branch to the thumb, that sometimes divides into two
which pass up on the anterior or volar surface, and some-
times 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, proceeding
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 another
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 ofthe ulnar and interosseal
                      Arteries-
Passes under several of the muscles which originate from
the internal condyle, and between the flexor sublimis and
the flexor profundus.  Before the  Ulnar Recurrent goes off
from this vessel, the interosseal  artery often leaves
it. This  recurrent artery  passes upwards between 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 ofthe radial artery, very near the commencement
of the interosseal ligament. 
Interosseal and Ulnar Arteries.        271
              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 Inte-
rosseal 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 contact
with the ligament, and gives branches  to the contiguous
parts in its course.  It generally perforates the interosseous
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 interos-
seal 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 ULNARartery proceeds among the muscles obliquely
downwards, and is not superficial until it has arrived within
three or four inches ofthe carpus: it then continues towards
the hand, sending off very small branches in its progress. 
 272        Course of the Ulnar Artery, and
 It passes over the annular ligament 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 palma-
 ris, and over  the  tendons 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 to-
 wards the radial edge, and, after sending branches to the
 fingers, &c, from its convex side, terminates near the root
 of the thumb, by anastomosis with that important branch
 of the radial artery, 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 me-
 tacarpal  bone of the little finger, a branch  which passes
 between  the flexor tendons and the metacarpal bones, and
 anastomoses with the Arcus Profundus. It then generally
 sends off a branch to the inner or radial 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 
     Its Ramifications on the Hand and the Fingers. 27$
 of the fingers on which they are placed* They are situa-
 ted on the angle, if it may be so termed, which is formed
 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 anas*
 tomose with each other, especially near  the joints.  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  anas-
 tomose  with their fellows  of the  opposite  side. Some
 also go to the back of the fingers.*

  ** The distribution ofthe radial and ulnar arteries in the hand, is verty
 different in different subjects.
  Upon examining a large number of injected preparations in Phila-
 delphia, it was found that, in a very small majority of them, the ulnar
 arteiy formed an  arcus sublimis, whose branches extended as far as
 the ulnar side ofthe 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 ofthe digital branches,
 viz. the first two on the ulnar side. In such cases the radial artery ge»
Tierally made up the deficiency of the ulnar, but In a  few instances th*
 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 stili more deficient, and
 the radial was proportionally  extended.
  , Voir. If.               2 M 
274             Bronchial Artery.
                    SECTION III.

  Ofthe Branches which go off between the arch and
        the great bifurcation ofthe AORTA.

                       PART I.
              In the Cavity ofthe 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 ramifi-
 cations of the trachea,  and  the substance of the lungs.
 They are  not large, and are very irregular as  to number
 and origin.
   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 branches
 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 
Intercostal Arteries.
275
intercostals that are spent upon  the  oesophagus. They
occur in succession, and sometimes are five or  six in
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 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 rib  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
* See Vol. I. page 89. 
276            General Account of the
backwards,  sends  ramifications  to  the muscles of tht
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.
  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 ofthe 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
Spermatics,  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 
               Arteries ofJhe Abdomen-           277
laterally, like the intercostals, to the parietes of the abdo-
men, and to the  muscles, &c, on  the back, which are
contiguous to them,

                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 coeliac 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 an external branch. Each of them generally
sends branches to the cardia or oesophagus, to the glandulae
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 stomach,
the liver, and the spleen. It projects from the anterior
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, i%
generally divides into three branches, which  pass to the
stomach, the liver, and  the spleen, and are, therefore,
denominated the gastric or coronary, the HEPATIC
and the SPLENIC arteries.
   The first mentioned branch may be called 
278
Distribution of
     The SUPERIOR coronary or GASTRIC artery,
To distinguish it from other branches, soon to be describ-
ed. It is commonly in the center of the  three great rami-
fications ofthe coeliac, and is also the smallest of them. It
proceeds from its origin to the upper orifice ofthe 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 laminae
of the small omentum,'and sends off successively branches
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 coeliac 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 superior

  * This artery sometimes sends a branch to the liver.  When this is
the case, it is always very large. 
                  the Caliac Artery*  ■            279
coronary. This branch is called the Pylorica, and some-
times it arises from the artery next to be mentioned.

           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 ofthe 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 stated 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 
 280          Distribution ofthe Splenic
 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

           The gastrica inferior sinistra,
 Is sometimes, but not often, very large: Its course is
 from left to right. It is situated between the laminae 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
 ofthe 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 abdomen
 by the aorta, is not very different in size from  the coeliac,
 and originates about half an inch below it. It is distributed
 to the small intestines;  to that portion of  the great intes-

  * 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*     281
tine, -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 por-
tion of the duodenum, to the  commencement of the me-
sentery.  When it has  arrived between  the  laminae of
that membrane, it descends  in  a  direction which cor-
responds 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 send3 two or three branches to
the transverse part of the  colon,  to the right portion of
the colon, to the beginning of the  great intestine,  and  the
contiguous portion of the ileon. These branches are com-
monly termed the colica media, colica dextra, and
ileo colica.  From  the convex side of  the curve,  the
SUPERIOR MESENTERIC sends off the  important
branches which pass between the laminae ofthe mesentery,
and supply the Small Intestines. These branches are numer-
ous, 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 repeated 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 intes-
tines. Some of them anastomose with each other on the
coats of the intestine; but an immense number of minute

                 * See Vol. II. page 11.
   Vol. II.             2 N 
 282     Distribution ofthe Inferior Mesenteric.
 arteries  are  continued  to the villous coat, so that, when
 they are successfully injected, the surface of that coat ap-
 pears uniformly coloured by the injection.*

        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 emulgents,
 and  the great bifurcation of the  aorta, and proceeds
 downwards, inclining to the left, but keeping near to the
 aorta.  There  are generally three branches distributed 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 Mesocolic Arch.  The ramifications of the other
branches frequently anastomose 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

  * See the account of the termination of these arteries, at page 107
of this volume. 
       Arteries ofthe Kidneys and Renal Glands.    283
that intestine and the sacrum, where it often divides into
two branches, which continue near to the termination ofthe
rectum.  From them proceed many ramifications that are
spent upon the rectum. Some of these ramifications anas-
tomose with each other, and others with the ramifications
of the hsemorrhoidal  artery, soon to be mentioned.

       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 direction
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 approach near
the concave edges of the kidneys, each emulgent com-
monly 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 renales.
There are almost always several of them appropriated 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 are supplied by the 
284
Spermatic Arteries.
                 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 little below the
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 psoas 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 con-
tiguous 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 
  Arteries above and at the bifurcation ofthe Aorta.  285
the aorta between the thorax and pelvis.  There are four
or five  of  these  vessels on  each  side, and they are
denominated

                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
coccvgis, and sends off lateral branches, which are spent
upon the contiguous parts, and inosculate with the arteriae
sacrae laterales.

                   SECTION IV.

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

             The PRIMITIVE ILIACS
Form an acute angle with each other.  They proceed
downwards behind the peritoneum, very near the margin
ofthe pelvis, without sending off any branch of importance.
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. 
286
General Account of the Internal Iliac.
     The EXTERNAL 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 ofthe side ofthe 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 ftetal 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 ofthe os ileum; and the ischiatic,
which passes downwards on the outside of the tuberosity
ofthe ischium.
   The first of these large ramifications passes outof the pel-
vis 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 tuberosity
of the ischium.
   The  first of the smaller branches which the internal
iliac commonly sends off, is called the 
Smaller Branches ofthe Internal Iliac.      287
                    Ileo Lumbalis:
It sometimes arises from the gluteal artery, and sometimes
from  the  main trunk of the internal iliac. It passes out-
wards 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 ramifies
on the iliacus internus muscle, and is spent on the con-
tiguous parts.
  There are also two or three small arteries called

               Arteria Sacra Laterales,
Which sometimes arise singly, and sometimes in common,
from  the  great trunk.  They also occasionally originate
from the gluteal artery. These  vessels enter the  anterior
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. 
 288      Smaller Branches ofthe Internal Iliac.
   From the anterior side o*f the internal iliac, or from one
 of its great branches, an artery often arises which passes
 out of the pelvis through the aperture in the margin of the
 ligamentous membrane which closes the foramen thyroi-
 deum ofthe 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 internus  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 inter-
 nal 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  Hemorrhoidal,
 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

  * See Astley Cooper's great work  on Hernia, Vol. I.
  There is reason to believe that this position ofthe artery occurs more
frequently than has been supposed. 
         Larger Branches ofthe Internal Iliac.     289
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,

                    The Uterine,
Which originates either from the internal iliac, near the
origin ofthe ischiatic, or from one of its 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,,
proceeds exteriorly through the sciatic  notch  above the
pyriform muscle, very near  the edge of the bone.  On
the outside 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 ofthe internal iliac, passes through
the sciatic notch below  the pyriform muscle, and proceeds
downwards, between the great trochanter ofthe 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
   Vol. II.             2 O 
 290                Pudic Artery.
 the os sacrum and coccyx, and the contiguous small
 muscles.
                 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 transversus 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 ofthe urethra
 it sends a branch into it, which is continued into the corpus
spongiosum urethrae, and  ramifies  there minutely.
  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 
      External Mac. Branches of the External Iliac. 291
direction. Its ramifications appear to be distributed through
the internal structure of the corpus cavernosum, 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-
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 out-
side, and the internal iliac vein on the inside. As it passes
under-Poupart's ligament, it is immediately  anterior  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
upwards 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 muscles',
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- 
292     General Account of the Femoral Artery.
monly divides into branches, which often inosculate with
the ramifications of the internal mammary.*
   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 ofthe 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

  * Several respectable surgeons have been taught by experience,
that when the abdomen is distended by ascites, the position of the
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
Qie superior superior spine ofthe ileijim. 
  Profunda and Circumflex branches ofthe Femoral. 293
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
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 
294  Branches ofthe Profunda and the Femoral.
circumflexa interna and externa. It then passes downwards
behind the trunk of the femoral,  and sometimes 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  descends in
the course of the  rectus femoris muscle, and  some of its
ramifications extend near to the outside ofthe 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.           295
                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 os
 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 Inferior
 Internal, and The Superior and Inferior External Articu-
 lary 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 External artery 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. 
296              Arteries ofthe 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 ofthe 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. 
              Anterior Artery ofthe Leg.          297
   The main trunk, which continues downwards, is called
the posterior tibial artery;
   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 ofthe leg, passes down
close to the interosseous ligament, with the tibialis amicus
muscle on  the inside, and the extensor communis on the
outside, in the first part of its course; and afterwards, 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 partof the tibia. It proceeds thence
with the tendons ofthe extensor digitorum pedis, under the
annular ligament, to the upper surface ofthe foot, on which
it continues to the interstice of the first and second meta-
tarsal 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
  Vol. II.              2 P 
298    Posterior Tibial and Peroneal Arteries.
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
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
continues on the back  of  the tibia, behind the  internal
ankle, to 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. 
                  Arteries of the Foot.             299
   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
rather obliquely inwards,  between the  gastroc  nemius
internus, which is posterior to it, 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 ofthe 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 ofthe great toe and the bones
of the tarsus. It then  divides into two branches—the in-
ternal 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

      * This artery sometimes comes off from the popliteal 
300             Arteries ofthe Foot.
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
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 a.>d 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
exhibiting the  distribution of  the  branches of  the  aorta.
which we spent upon the substance of the Heart
  The COMMON TRUNK
Of the Right  Subclavian and
   Right Common Carotid.
At the Curvature,   ■<
the side of the trachea,  and <
divide »t  the upper edge of
the thyroid cartilage, into
The EXTERXAL  CAROTID,
  which is principally appropri-
  nted to the exterior of  the
  head, and the upper parts of
  the neck.   It gives off
The Facial

The Inferior Pharyngeal

The Occipital

The Posterior Auricular


The Internal Maxillary


The Temporal
C The Thyroid Gland.  Tin- Larynx.
\ The parts contiguous to the On llyoidi-s.
CThe Tongue.  Sublingual claml.   The Pha-
i                 rrynx.
CThe side ofthe Face. Chin. Lips. Parts under
f             the Lower Jaw.
CThe Pharynx andcontiguous parts.
I The cavity of the Cranium.
  The posterior part ofthe Cranium externally.
C The cavity ofthe Tympanum.
I Parts contiguous to "the external Ear.
•TThe  Superior and  Inferior Maxillary bones.
J The  Fauces.  The Pterygoid muscles.  The
1 Palate.  The Dura Mater. The Interior of the


c The anterior and lateral part* of the Cranium,
£   externally.
The Ophthalmic Artery, to the Eye and its appendages.
The  Middle Artery of $ The middle, and part of the posterior portion
      the Brain        £   ofthe Cerebrum.
The LEFT SUBCLAVIAN.
Each of the Subclavian! is the first portion ofthe great artery of the
  Upper Extremity of its respective side.
It gives off
Anterior portion ofthe
         of the Tho-
       _he Mammx.
  -rcbellum.  The pos-
Thc Scapular)', to die
  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 Scapulaiy Artery,
To the muscles about tine  sca-
  pula and the posterior part of
  Utc thorax.

      The Circumflex*,
To the parts about the upper end
  'ofthe Os Humeri.
   The HUMERAL.
The third portion gives off
The Profunda Humeri

  Profunda Inferior,
To muscles on the Os
      Humeri.
n-  r
At the Elbow it gives off
 The mm

which send off
  Branches to the muscles in it

'  A recurrent branch.
,  A branch lo the thumb.
  To the rulial side of the index
  To the arcus profundus.
The arcus sublimis in the palm of
  the hand, which sends or" the
  digital arteries to the sides of
  the fingers.
K. II.  The lBW»m»l and  the Dinar
  . bine off from the H-aaMt**l,IV a <«n-
  aOBtrank.
Between the cui
  ture and the great <
  Bifurcation,
The isfmuc
The Phrenic Arteries  -
CtBLIAC ARTERY
SUPERIOR MESEXTERIC
Capsular Arteries  ■
EMULGENTS
Spermatic* -
IirrxBioa vxsxHTtmics
Lumbar Arteries
The MIDDLK BACaiL
At the great Bifurca- <
 The PRIMITIVE 1LIACS,
)nc of which is divided on cacti
 side of the Pelvis into
           it ofthe lower intercostal spaces,
To the diaphragm.
To the stomach, liver, and spleen.
Almost all the small intestines, and part of the great
Glandular He nales.
The Kidneys.
The Testicles.  The Ovaries.
The left portion of ihe Colon, and the Rectum.
        *-....     ,.,   ,. .-----   Thcspi
The  Sacrum,  internally and  ex
    rnally.
    Cauda Equina.

The Bladder.
    Uterus.
    Rectum.

The Muscles on the upper and
  interior part ofthe thigh.
The Hip joint, &c.

     Muscles on the lateral and
  posterior parts of the Ossa lit-
The Muscles, tc. on the upper
  and the posterior part of the
  thigh.
The Organs of Generation.
  The  EXTERNAL ILIAC,
The firat portion of the great
  artery of the lower extremity, t
  which passes under Poupart's
  ligament to the thigh, but pre-
  viously sends off
  The L'ireumftexa Ilii,
A small artery, which is
  spent upon  the iliacus
  internus, and the  con-
  tiguous portions of the
  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
     Artery.
The  second portion
  of the great artery
  of the lower extre-
  mity begin at Pou-
  part's ligament.  It
  sends off
 The External Pudic
To the exterior parts of
  the Organs of Gene-


   The Profunda,
And its  branches,  the
  two circumftexse,  to
  the  muscles  on  the
  thigh.
  Tlit 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 su pply the contigu.
  ous parts.
It divides into
   The AXTXUOR TIBIAL,
Which proceeds down the an-
  terior part ofthe leg to the ■
  top of the foot, from which
  it descends to the sole.  It
  sends off
      The raftoxxAL,
Which is near the fibula on the
  posterior side of the interos-
  seal ligament.  It is spent
   The rosTxaioa tisiax.
Which passes down behind the ^
  tibia and the internal ankle *
  to;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
  ofthe leg.
Tarsal and metatarsal  branches
  to the upper part of the foot.
The muscles on the outside of
  the leg.
The ankle and the outside ofthe
  foot.
Branches to the muscles.
The  medullary  artery of the

The internal and the  external
  plantar arteries, to the parts
M. B. The Fonrrwr Tibial and the IV-
 rooenl enme off from the Popliteal by 
 
301
                   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
 connexion with the  heart; for it communicates with that
 organ in such a manner that, when viewed from before, it
 appears 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 injec-
tion, and the pulmonary vessels are injected first; the right 
 302              Veins ofthe Heart.
 auricle is so much pressed upon from behind, by the vessels
 which go to the right lung, that the direction of the superior
 and inferior portions ofthe vena cava, which thus commu-
 nicate 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 ofthe 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 ventricle,
 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
 round the  basis of the  left ventricle, it sends off several
branches, one  of which is considerable, that proceed from
 the basis towards the apex of the heart, ramifying on the
 surface of the left ventricle.
   A  second vein, much less than  the first,  appears to
 proceed  from the great vessel  at  its commencement,*
* It often opens into the auricle by a separate orifice. 
      Superior Vena Cava and its Great Branches.   303
and continues on the lower flat surface of the heart, be-
tween  the  two ventricles, to the apex, accompanied by a
branch of the right coronary artery. This has been called
the Middle Vein of the heart.
   In addition to these there are several veins which begin
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.

Ofthe SUPERIOR or DESCENDING  VENA
  CAVA, and the Veins which communicate-with it.

   THIS  great vessel proceeds  upwards  from the su-
perior and posterior part of the right  sinus or  pouch of
the heart;* and a portion of it is so involved  by the peri-
cardium,  that it seems to be included in that sac, as the
heart is in this situation. It is somewhat anterior as well as
to the right of the  aorta. It continues above  the peri-
cardium, 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 be-
hind or within the origin  ofthe left sterno-mastoid muscle,
it divides into the left subclavian, which preserves a trans-

   * See the description ofthe  heart, in page 52, of this volume. 
 304                Vena Azygos.
 verse course, and the left internal jugular, which proceeds
 to the cavity of the cranium  by the foramen lacerum.
   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 ofthe 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 pul-
 monary artery and right branch of the trachea, and then
 curves downward 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 vertebra. 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.

   * This bronchial vein sometimes arises from the superior cava. 
                Inferior Intercostal Veins.           305
   The  Inferior Intercostal Veins originate  directly  or
indirectly from the azygos.  In some  cases there is no
Superior Intercostal on  the  right  side;  and then the
tWo or 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 vertebra, and sends off  those Left
intercostal  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 trunk* of the subclavians and
internal jugulars united.
  Vol. II.              2 Q 
306          Superior Intercostal Veins.
  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.

           The superior intercostal Veins
Are somewhat different on  the two sides. That on tHe
right is often the smallest and the least extensive.  It
commonly  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 inter-
costal 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
vertebral canal,  it sends off an external branch, which 
Vertebral Veins..
307
 passes up, before and nearly in contact with, those pro-
 cesses, 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
 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 aper-
 tures between the vertebra. One of these branches passes
 backwards to the muscles of the neck; and the other pro-
 ceeds 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 
308             The Internal Jugular.
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
between the internal and external jugulars, but they are
divided very differently in different subjects.
   The  Internal Jugular, however, almost always passes
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 ofthe thyroid cartilage
and the angle of the  lower jaw, it often sends off branches
which are very different in  different subjects, but com-
monly pass to the anterior  parts of the  neck and  face:
above these it generally  sends another to communicate
with  the external jugular. One of rthe branches which
often go off from  the internal jugular is  that which cor-
responds with  the superior  thyroid or laryngeal artery.
This vein, which has sometimes been called the Guttural,
sends many ramifications to the thyroid gland. The Ranu-
lar veins, which are so conspicuous under the tongue, are
also derived from it; 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

  • When the veins ofthe neck 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 distention.
  It also often appears thai the  general arrangement of the exterior
vein is different on the two sides ofthe head, and neck. 
                 The Internal Jugular.             309
aforesaid foramen, the internal jugular terminates in the
lateral sinuses of the dura mater.*  These  and the other
sinuses within the cavity ofthe cranium are  important por-
tions of the venous system, which are interposed between
the smaller branches spread upon the pia  mater and the
great  trunks  of the neck.  They are described  in the
account of the brain, (Vol. I.  p. 319). Into these sinuses
the very numerous veins of the pia mater open, proceed-
ing 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 ofthe 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.f Its ramifications
correspond generally with those ofthe ophthalmic artery;}
and some of them pass out of the orbit to anastomose with
the branches of the facial vein.
   The superficial veins ofthe 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

  * It is asserted that the internal coat, or lining  membrane of the
internal jugulars, is continued into the lateral sinuses, and extends
ihrougliout all the sinuses ofthe 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.
  f See the account of this fissure in Vol. I. p. 56.  .
  $ The Vasa Vorticosa ofthe choroides are one of  the exceptions to
this. See Vol. I. p. 354. 
310            The External Jugular.
that vein much nearer the shoulder. There are sometime*
two external jugulars,  an anterior and a posterior, nearly
oi t qual size. More frequently one of them is much smaller
than the other.  In a majority of cases, the principal ex-
ternal jugular  goes off near the junction of  the internal
jugular and subclavian, as  above  stated, and proceeds
upwards 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 pro-
ceeds upwards.  Near the angle of the jaw, it often com-
municates  with the  internal jugular:  it then continues
upwards, covered with the parotid gland, near the tem-
poral artery, and finally divides into superficial and deep-
seated temporal 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 
     General Account of the Great Vein of the Arm.  311
muscles, as is the case wi.h  the arteries, but befoie the
anterior muscle. It soon joins the great artery ofthe 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 ofthe
biceps muscle, sending off many subcutaneous blanches.
Near the external condyle of the os humeri, it generally
sends off a branch towards  the middle  of the  anterior
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  ofthe 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 ofthe
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 
 312  General Account ofthe Great Vein ofthe Arm.
 part of the fore arm.  This vein generally sends off  a
 branch which proceeds  internally, and anastomoses with
 the deepseated veins of the forearm.
   There are frequently two other branches of the basilic
 vein. One, which is small, passes down on the ulnar side
 of the anterior part of  the forearm,  but does not extend
 to the wrist.  The other  passes  down on the ulna, and
 gradually proceeds to  the  back of  the  hand, when it
 divides into several branches, one of which is generally
 appropriated to the litde finger.
  The AXILLARY vein, after  the  basilic leaves it,
 sometimes divides into two branches,  and  sometimes
 continues undivided. In either case  it accompanies the
 humeral  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
 accompany each of the three arteries of the fore arm.
 These  ramifications sometimes  communicate with each
other by anastomosing branches near the elbow, and they
communicate also with the superficial  veins.

    The superficial veins of the arm are so different in dif-
      ferent subjects, that a general description will rarely
      apply accurately to an individual case. It may, however,
      be observed, 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 radial side of the arm.  The  superficial
      veins, on  the ulnar side of the forearm, 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. 
          Situation ofthe Inferior Vena Cava.       313


                    SECTION II.

Ofthe INFERIOR VENA CAVA, and the Veins
            which are connected with it.

    THIS  great  vessel exceeds  the  Superior  Cava in
diameter. 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 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 accompanies 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.

      * Sometimes it is completely surrounded by the liver.
   Vol. II.               2 R 
314             Vena Porta Ventralis*
                 The  HEPATIC Veins
 Pass off from the vena cava, nearly at right angles, info
 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.

             The VENA PORTARUM
 Passes downwards from the great sinus ofthe 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, eithet 
       Superior Mesenteric and Emulgent Veins*    315
from the main trunk or its branches before they enter the
spleen, the vena 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;
Which 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.
  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. 
 316    Small Branches ofthe Cava. Iliac Vein&.
    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 downwards
* 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 de-
 nominated Corpus Pampiniforme. These branches proceed
 in the spermatic cord to the back of the testis.  The prin-
 cipal 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, he.

                   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 June- 
          Internal Iliac and its Ramifications.      317
tion 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 venjE 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
they form a remarkable plexus on  the lateral and inferior
portions of the  bladder, and on the vesicula 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 caver-
nosa, 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  vena vesicales form a  considerable
plexus  on each  side of the bladder and vagina. Many
veins pass from these to the upper portions ofthe bladder
and the contiguous parts, and form plexuses. The clitoris

   * The pudic veins accompany the arteries of that name. They com-
municate with the plexus, as above mentioned, and continue into the
penis. 
318      Ramifications of the External Mac.
has a dorsal vein like the  penis, and it originates in a
manner analogous to the dorsal yein of the male.

           The EXTERNAL  ILIAC Vein.
The great trunk of the veins of the lower extremity pro-
ceeds on the inside ofthe 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
divides into branches which accompany those ofthe artery
of the same name.

                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
outside 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 
                   Veins of the Leg.               319
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 thigh, 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.
  The  femoral vein,  after parting  with the saphena,
soon sends off the vena profunda, and the circumflexa
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 ana-
logous 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 
320 Instances of peculiar arrangement of the Veins.
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
surface of the foot, about the middle of which it inclines
towards the great saphena, and forms with it the anasto-
mosis already mentioned.
  The popliteal vein, after passing across the articulation,
ramifies like the artery, but it 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 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.
* See note to p. 140, of this volume. 
Pulmonary Vessels.
321
       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 pro-
 ceeds  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 ofthe aorta, which is almost in contact with it.
 This ligament  was originally  the canal that formed the
 communication between  the  pulmonary artery  and  the
-aorta of the foetus.f Each of  the  great branches of the
 pulmonary artery takes a  direction backwards, and to its
 respective side.  It  soon joins the corresponding branch
 of the trachea and the two pulmonary veins, being anterior
 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
 thus 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

       * See page 60 of this volume.     -j- See Page 70.
  Vol. II.             2 S 
322             Pulmonary Vessels.
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
accompany 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. 
       SYSTEM  OF ANATOMY.


                    PART  X.


                 OF THE NERVES.

 J HE 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 fasciculi
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 appears 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
foramina in those bones, this coat, derived from the dura
• See Volume I. page 33". 
 324        General Structure of the Nerves.
 mater, appears to separate into two lamina. The exterior
 lamina  combines with the periosteum, and  the  interior
 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 cellu-
 lar 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

   * 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 Generate."__.Fon-
 tana, " Treatise on the  Poison of the Viper."—Reil, " Exercitationes
 Anatomies."—Scarpa," Annotationes Academics."—Prochaska, " De
 Structura Nervorum."
  I regret that it has not been in my power to procure Reil, Prochaska,
 or Scarpa. 
                Plexuses.—Ganglions.            325
with other new ramifications to form other new trunks.
These new trunks divide again, and form new combina-
tions in the same way.
  The trunks last formed proceed to the different parts of
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 and
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 appeals  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
different 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 
 326             Structure of Ganglions.
 fibres, 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 fine cellular
 substance, which is vascular, moist and soft.  It is  assert-
 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
 important 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 anterior
 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 of nervous
 fibrillse, so as to bring together those fibrils which originally 
                Reproduction of Nerves.            327
belonged to different cords, seems to have been kept in
view throughout the whole arrangement of the nervous
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 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.

  * See Monro's Observations on the Structure and Functions of the
Nervous System. Plate xviii.
  f See London Philosophical Transactions, for 1795, Part I. 
328
Olfactory Nerves.
            NERVES OF THE BRAIN.
  The nerves which go off from the brain 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
distributed.
  Those which go to the nose are anterior to all the others,
and are therefore denominated

    THE FIRST PAIR, OR THE OLFACTORY NERVES.
They arise by three 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
occupies 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 
           Second and Third Pair of Nerves.        329
 bone—one running near to the septum, and the other to
 the opposite surface ofthe 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 ofthe 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
 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.f Anterior to
 this substance they come in contact with each other, and
 again separate, in such  a way, 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 the account «f 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 ofthe crura cerebri, and make their ap-

       • See Vol. II. Page 7.       f  See Vol. I. p. 334.
  Vol. II.              2 T 
330            Fourth Pair of Nerves.
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 ofthe 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 Branch is spent principally upon the rectus
superior muscle of the eye, but sends a twig to the levator
palpebral. The Inferior Branch is distributed to two of the
recti muscles, viz. the internus and the inferior, and  also
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,:}: 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

  *  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.
  f See Volume I. page 354.
  \ Ibid. Page 336. 
                 Fifth Pair of Nerves.             331
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
thre-  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.
  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 Ganglion ofGasser, 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, and the Inferior Maxillary. 
332
First Branch ofthe Fifth Pair.
                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
ofthe others extend upwards on the head. Some are dis-
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 
           Second Branch ofthe Fifth Pair.        333
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
and 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
proceeds from the semilunar 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 itsends downwards
two branches  which unite  together almost  immediately
after their origin, and, as soon as they have united, enlarge
into a ganglion.*  This ganglion is called  the  Spheno-

 '* Sometimes,a single branch passes downwards instead of two; but
it forms a ganglion in the same place. 
334      Second Branch ofthe Fifth Pair: or
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.
They subdivide into fine twigs that proceed forward to the
alveoli of three or four of the  last molar teeth, and pene-
trate each ofthe 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, vvhich accompanies it for some distance,  and then 
               Superior Maxillary Nerve.          335
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 back-
wards, 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 sub-
stance almost as firm as cartilage, which closes the anterior
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 ofthe seventh pair in
the larger canal, called the Aqueduct of Fallopius, at the
first turn in that canal.* The other branch of the pterygoid
nerve  proceeds to  the  Foramen Caroticum, 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

  • The late Mr. John Hunter believed that this nerve parts from the
portio dura at the lower end ofthe aqueduct, and is the chorda tympani. 
 336        Third Branch ofthe Fifth Pair.
 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 ofthe branches which thus  enter the nose are spread
 upon the 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 Inferior  Maxillary Nerve, or  the Third Branch
                 ofthe  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
  • The curious distribution of this nerve appears to have been known
to the late John Hunter, and also to Cotunnius; but it is minutely
described by Scarpa, and is delineated  by Soemmering in his plate
 of the nose.—See " Observations on certain parts ofthe Animal Eco-
 nomy," by J. Hunter,  page 219,—and also Scarpa  " De Organo  Ol-
factus." In this last are  some interesting obiervations relative  to the
 ducts of Steno. 
     Lingual Branch ofthe Upper Maxillary Nerve. 337
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
maxillary continues to the upper  and  posterior orifice
ofthe canal in the lower jaw. Before it enters this canal it
sends a branch to the sub-maxillary gland, and to the mus-
cles under the jaw.  It then enters the canal,  attended by
bloodvessels, and proceeds along it to the anterior maxil-
lary foramen, on the side of the chin, through which
it passes 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
  Vol.. II.              2 V 
 338       Sixth and Seventh Pair of Nerves.
 branch  forwards, which supplies the remaining teeth on
 the side to which it belongs. After passing out, through
 the anterior  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
 muscle of the eye.

           THE SEVENTH PAIR OF NERVES
 Comprises  two distinct cords 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 
    Composition of the Seventh Pair.—Portio Dura.  339
Seventh Pair, and distinguished from each other, in con-
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 Portio 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 ofthe temporal bone; and the Portio Dura 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 Portio 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
petrous 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.
                v* See Volume I, page 394. 
 340       Chorda Tympani.—Pes Anserinus.
   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
 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  mastoid 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
 ofthe fifth pair, as has been already mentioned.*
   The Portio Dura, after  passing out of the Foramen
Stylo- Mastoideum, 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

  * The late John Hunter believed that the chorda tympani is merely
 a continuation of the twig of the pterygoid branch which joins the
portio dura above.—See Observations on certain parts of the Animal
Economy, page 220. 
        Composition ofthe Eighth Pair of Nerves.    341
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-
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

  *  A most minute and laborious description ofthe nerves of the face
was published by the celebrated Meckle, in the seventh volume of
Memoirs of the Royal Academy  of Sciences of  Berlin, for the year
1751, accompanied with a plate, exhibiting the  side of the head, of three
times the natural size. This is republished  in the Collection Aca-
demique: Partie Etrangere.—Tom. viii. 
342          Glosso-Pharyngeal Nerve.
of Willis, vvhich 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-
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, they 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. Afterwards
it sends off several twigs to the muscles of the pharynx
and  its  internal membrane, and also some twigs which
unite with others  from the upper cervical ganglion of  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 lingualis,
and the various muscles inserted into  the tongue, termi-
nates in small ramifications that are spent upon the sides
and middle of the root of the tongue, and upon the large
papillse. 
    Superior Laryngeal Branch of the Par Vagum. 343
      i
                  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 in 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 glossopharyngeal;  that soon after
it sends off a branch called the Pharyngeal, which unites
to one from  the accessory nerve,  and to  one or more
from the glossopharyngeal, and proceeds to the middle
constrictor of the pharynx, 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
Laryngeal 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  foramina, 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 of the larynx, and to the thyroid
gland. 
344      Recurrent Branch ofthe Par Vagum.
  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, each 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
the Larynx; which, from  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 off 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 vvhich lines the back part of
the larynx and the contiguous surface of the pharynx. 
          Par  Vagum.—Pulmonary  Plexuses.      345
   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 bron-
chia? 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
mucous glands which are upon it; and some pass to the
oesophagus.
  When the par vagum 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-
chiae.  It has been  said,* that the small twigs, into which
they divide, very generally penetrate into the small  rami-
fications of the bronchia?, and are spent upon their internal
membrane.
  Soon after  sending  off the nerves of the  pulmonary
plexus,  the Par Vagum proceed downwards upon the

  *  See Buisson, in the continuation of the Descriptive Anatomy of
Bichat.
  Vol. II.             2 X 
346      Termination of the Par Vagum, fcrc.
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 stomach. 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 thick although short, proceeds to
the solar plexus.

             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
ofthe 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 it receives  filaments from the medulla oblongata. 
       Different Functions ofthe Laryngeal, &c.   347

   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 recurrent nerves, therefore, seem
       essential to the formation of the voice.  The laryngeal
       nerves are necessary to its modulation.
        The history of the investigation  of this  subject is
           contained in Mr. Haighton's paper in the third
           volume of Memoirs  of the Medical Society of
           London. 
348   Ninth Pair of Nerves.—Descendens Noni.

             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 ofthe posterior portion
ofthe 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 divides into
ramifications, which, at the anterior edge of the hyo-glossus
muscle,  begin to enter into 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 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 rami- 
         Sub-Occipital, or Tenth Pair of Nerves.     349
 fications of various sizes from the first, second and third
 cervical nerves, which form a bow under the sterno-mas-
 toid muscle,  from which  ramifications go to the lower
 portions of the sterno-hyoidei and thyroidei muscles and
 ofthe coraco-hyoidei.

           OF THE CERVICAL NERVES.
   The tenth  or last pair of the head, commonly called
 the  Sub-occipital, may be  arranged  with these 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 outwards
 immediately  under  the  vertebral  arteries, and form  a
 ganglion, from which proceeds an anterior and a posterior
 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. 
350
First and Second Cervical Nerves.
              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  anterior
 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 complexus 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 jugu-
lar vein,  and others unite with the descending branch of
the ninth pair of the  head.  A small branch is  also con-
 cerned 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

  * This arrangement is  common to the nerves of the  spine. The
 ganglion is formed by the posterior fasciculus. 
           Third Cervical, and Phrenic Nerves.      351
of. the anterior, 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.*—The posterior
branch 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
ofthe head. Some of its branches unite with twigs of the
accessory nerve,  and others are spent upon the muscles
and  integuments 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 amicus, 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-

   * These superficial branches have sometimes been described as
coming from a plexus; but they often arise directly from the Second
Cervical nerve 
352 Remaining Cervical Nerves.—Brachial Plexus.
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
proceeding in a more perpendicular direction.   When
they arrive  at the diaphragm, they divide into many ra-
mifications which have a radiated arrangement, and  ter-
minate 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
successively from the  Medulla  Spinalis,  between  the
vertebrae, 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
described, 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 ofthe neck, into the
arm-pit. It commences in the following manner. The fourth 
          Construction of the Brachial Plexus.      35$
and fifth cervical nerves proceed downwards, and, after
uniting to each other about an inch and a half below their
ogress  from the spine, they separate again, almost im-
mediately, into two branches.
   The sixth cervical nerve, after passing downwards, di-
vides also into two branches, one of which unites with 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 ofthe 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 Cutaneus; The Median;* The Cubital,

                • Sometimes called Radial.
   Vol. U.                2 Y 
354     Musculo Cutaneus and Median Nerves.
or Ulnar; The Internal Cutaneus; The Radial or Muscu-
lar Spiral; an:, the Circumflex or Articular*
   The MUSCULO CUTANEUS,  Or  PERFORATING NERVE8
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
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 ofthe 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 this 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 ofthe 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, perforates thfc 
Cubital or Ulnar Nerve.            355
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 tendons
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 tendons 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 at acute
angles, and subdivide so as to send a ramification to each
side ofthe thumb, ofthe index,  and of the middle finger;
and to the radial side of the ring finger.
  The cubital or ulnar nerve is also of considerable
size. It passes down on the inside of the triceps extensor
muscle, to the great groove formed by the olecranon
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
between the flexor ulnaris  and the ulna, to the back ofthe
forearm and wrist, where, after sending ramifications to the
integuments and contiguous parts, it divides into branches
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. 
356      Radial, or Muscular Spiral Nerve.
  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.
  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
internus. 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 abont 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. 
        Internal Cutaneus and Articular Nerves.    357
branches, which are principally distributed to the thumb
and forefinger, and also to the integuments.
  The Profound branch proceeds to the back of the fore
arm under the radial extensor, and continues  to the back
of the wrist and hand. In 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 basilic 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 back-
wards 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
vertebrae.  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 
358                Dorsal Nerves.
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 vvhich 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 muscles and
pleura, but to the other muscles and the integuments  of
the thorax.
   Some of the  dorsal nerves differ from the others, as to
the ramifications which they send off.
   The First Nerve, of this  order, joins the lower cervical
nerves in the axillary plexus; but it sends off the ramifica-
tions 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 kncrcosto-humeral nerves. 
/
        General Account ofthe Lumbar Nerves.     359
  i he lower dorsal nerves supply the muscles and  inte-
guments ofthe 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 vertebva and the
sacrum.
  The first lumbar nerves arisefrom 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,
vvhich  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 Vertebrae,
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. 
360      Lumbar Nerves.—Lumbar Plexus.

             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, vvhich passes through
the aperture  in the  membrane that closes  the  foramen
thyroideum; the Crural Nerve, which passes under Pou-
part's ligament; and a third branch that proceeds  down-
wards, and joins the Fifth lumbar nerve. The Fifth lumbar
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,  as has been already stated, fur-

  • The external spermatic often comes off from the first lumbar
nfitve. 
            Obturator Nerve.—Crural Nerve.       361
nishes three nerves to the lower extremity, viz. the Cu-
taneus Medius, the Obturator, and the Crural Nerve.
   The Cutaneus Medius which arises from the union ofthe
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.
   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-
  Vol. II.             2 Z 
 362         Crural Nerve.—Sacral Nerves
 ted Cutaneous.—-They are distinguished by  the terms
 Cutaneus Anterior, Cutaneus Internus, &c, according to
 their situations.
   The  deepseated 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 Saphnus,
which has a different destination. It accompanies the great
artery of the thigh to the place where  it perforates  the
Adductors: it there separates fro n 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 Nrves
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
vvhich y,t-.s through the foramina of the sacrum, and  the
fifth between the sacrum and the os coccvgis.* The cords
of which they are respectively composed  arise bv 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
divide into anterior and posterior  branches.  The upper-
most of the anterior branches are large, and pass through
  • The sixth pair, when they exist, proceed in a groove in the os
 coccvgis.
  f The ganglions of the fourth and fifth nerves  are extremely small,
 and not so near the foramina as those ofthe others. 
             Sciatic Plexus.—Pudic Nerve.        363
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
ramifications to the sympathetic. They unite to each other,
and are joined by the last lumbar nerve, and by a branch
of the fmrth 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 integuments.
  From the sciatic plexus, or the nerves  which com-
pose it, several smaller branches go off. There are generally
£wo which pass off backwards through the ischiatic notch,
and are denominated Gluteal, as they are distributed to
the glutei muscles. From the lowermost of these a branch
descends on the thigh.
  The Pudic Nerve, vvhich is appropriated  to the organs
of generation, also  passes off from this plexus, and ap-
pears to consist of fibres vvhich are derived from each of
the nerves  that  compose it.  It proceeds  between the1
sacro-sciatic ligaments, and divides into two branches—an
inferior and a superior. The  inferior passes between the
erector  penis  and the  accelerator urinae muscles, and is
distributed to those muscles, to the bulb of the urethra and
the interior  of that canal, to the scrotum and dartos.
  The superior proceeds along the os pubis to the sym- 
 364         Course ofthe Sciatic Nerve.
 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 pelvi  through the  ischiatic notch, be-
 tween the pyramidalis and the superior gemellus musclei
 it then passes down to the back part  ofthe 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 ofthe 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 muscles
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
is different  in different subjects. It continues  in contact 
           Distribution ofthe Fibular Nerve.       365
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 ofthe gastroc nemius: it then passes inwards between
the long peroneus muscle and the fibula;  and descend-
ing between the muscles on the fronc of the leg, divides
into two branches, one of which inclines to the exterior
side 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 ofthe 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 ofthe 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. 
366        Distribution ofthe 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 Poste-
rior Tibial Artery;  descending with that artery to the
hollow df 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 ofthe os femoris, it sends off a
branch of considerable size called the Communicans Tibia,
or  Saphena Externa, vvhich  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 ofthe 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 
        Commencement ofthe Sympathetic Nerve.    367
roe,  giving off small branches in its course.  About the
middle of the foot it divides  into four branches, one of
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
branches are 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 ofthe toes and the flexor accessorius.
Near the  external edge of the foot, about the posterior
end ofthe metacarpal bones, it divides into three branches.
One proceeds to the outside ofthe 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 
 368       First Ganglion, and other Cervical
 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
 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 carotid artery, at its bifurcation, and are joined
 by twigs of the Portio Dvra  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. Sometimvs 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,  uriting 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 ofthe 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  tv igs, which are larger, proceed  from it
into the thorax, and go to the  cardiac plexus hereafter to
 be described.
  Opposite to  the interval between  the  fifth  and sixth
 cervical vertebrae it forms another ganglion, of an irregu- 
       Ganglions and Branches ofthe Sympathetic.   369
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
Cervical, or Thyroid Ganglion.—When the fourth, fifth,
and sixth cervical nerves do not send ramifications to the
sympathetic nerve above,  this ganglion receives  twigs
from them.
   The Middle Cervical, or Thyroid Ganglion, sends many
ramifications downwards.  Some of them enter the thorax
and contnbute  to  the formation of the Cardiac Plexus;
others  accompany  the inferior thyroid artery, and, with
twigs from the recurrent nerve, form a plexus vvhich 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-
eal, or  the First Thoracic.  It is almost constantly found
in 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.
   Vol. II.             3 A 
370         Branches ofthe Sympathetic.
   They arise principally from an arrangement of nerves
denominated the Cardiac Plexus, or Plexuses,  which is
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
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 left 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 
              Branches ofthe Sympathetic.         371
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 ofthe
Arteria Innominata to the curve of the aorta; continuing
between it and the pulmonary artery, to the anterior co-
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 ofthe 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 
372    Plexus formed by the Nerves ofthe Heart.
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 has been already  mentioned,  it  is principally com-
posed of branches from the middle cardiac nerve of the
right side, and the inferior cardiac nerve ofthe 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,
  * It has been 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 Splanchnic Branches.  37-3
 which unites with the intercostal nerve behind it, by two
 branches, and thus forms an indirect communication  with
 the medulla spinalis.
   From several ofthe 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, which  proceed down-
 wards on the sides ofthe bodies ofthe 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
 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 ofthe 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, vvhich commonly
 form small ganglions on each  side of the coeliac, 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. 
 374       Arrangement ofthe Nerves ofthe
   This 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 Caliac
 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
 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 solar
 plexus, and is the largest of all which proceed from that
 plexus. The Mesenteric Plexus at first nearly surrounds
 the artery, *nd proceeds with  it between the laminae of
 the mesentery. In this course it sends branches, with the
arteria colica dextra, to the transverse portion ofthe colon. 
                  Abdominal Viscera.              375
Between the laminae of the mesentery,  it sends ramifica-
tions  with all the branches of the artery, to the small
intestines generally; to the coecum, and the right portion
ofthe 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, vvhich are
arranged like a network on its anterior and posterior sur-
faces, 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
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, vvhich, 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 
 376      Termination ofthe Sympathetic Nerve.
 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
 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-
tebrae 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.

  • Although the testicle receives nerves which are derived from the
 Sympathetic, the penis and other external parts ofthe organs of genera-
tion do not: the nerves which accompany the pudic artery being derived
from those which unite to form the great Sciatic. 
       SYSTEM OF ANATOMY.


                   PART  XI.

          OP THE ABSORBENT VESSELS.

J  HE 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 ofthe body; and of the cellular membrane, in all
the various parts into which it penetrates; upon the inter-
nal surface ofthe stomach and the intestines; and probably
upon the skin.
  Those which originate in the Lower Extremities and
the Cavity ofthe 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 ofthe Head,  and the con-
tiguous parts, form a trunk which terminates in the same
place.  While the remaining absorbents, or  those pf the
Right  Upper Extremity, and the Right Side ofthe Head,
&c. 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
  Vol. II.             3 B 
j 78       Structure ofthe Absorbent Vessels.
the larger;  in  their progress to these large vessels, pass
through  certain bodies vvhich 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 coats 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, vvhich 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 
            Commencement ofthe Absorbents.        379
 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
 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 ofthe contained fluid,
 in consequence 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 branches  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. 
380              Conglobate Glands.
  Lieberkuhn believed them to commence in the form of
an ampullula.—See page 108 of this volume.
  The second Monro also  believes that  the absorbents
begin by very small tubes, with open orifices, in several
species of fish.*
  It is stated by Dr. Soemmering, upon the authority of
Iiaase, 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 Inferentia,
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.
   * See his work on the Structure and Physiology of Fishes, p. 34. 
Fluid Contained in the Absorbents.        381
There has  been much  diversity of sentiment respecting
the structure of these organs.*
   The absorbent vessels, in the  different parts of the
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 coa-
gulated 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.

  * 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
ofthe horsa.—See Philosophical Transactions, for 1796, Part I. 
382
                   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.

    Ofthe 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 acccomnany 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 int« 
        Absorbents ofthe Lower Extremity.         383
some ofthe popliteal glands, soon to be described; but they
are not numerous;  and the principal number continues up
to the glands ofthe groin. The absorbents vvhich originate
on the surface of the thigh,  as well as those vvhich 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 
384      Absorbents ofthe Lower Extremity.
artery, and terminate in the popliteal glands, which re-
ceive also the absorbents fr^m 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 ofthe glands ofthe 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  f< ur 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 
           Inguinal and External Iliac Glands.      385
 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
 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 vvhich
 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 tract 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 vena
cava, and the lumbar vertebrae. Most  if not all the  ab-
  Vol. II.              .1 C 
386        Absorbents ofthe Testicles, &c.
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
Superficial Absorbents of the scrotum commonly enter into
the upper inguinal glands, and thus  unite  to the great
body of absorbents.
  The Absorbents ofthe  Testicles originate in the body,
and the coats of the testicle, and in the epididymis; and
are remarkably large and numerous, f hey 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  ofthe Scrotum accompany
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-
quently several trunks vvhich 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 ofthe Pelvis and the Kidneys.
38.7
                    SECTION II.

   Ofthe 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 hv pogastric, or some of the contiguous plexuses.
   The Absorbents of the Womb are  extremely numerous;
and, in the gravid state, are very large. Those vvhich 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 ofthe Bladder pass to small glands on
its  lateral and  inferior parts, and finally join the hypo-
gastric plexus.
   The Absorbents ofthe 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- 
 388    Lacteals, or Absorbents of the Intestines.
 cial; they proceed to the lumbar plexus, and pass into
 different glands.
   Absorbent vessels can be  proved to proceed from the
 pelvis of the kidney, and the ureters, by artifices analogous
 to those above mentioned.
   The Glandula Renales are also supplied with absorbents,
 vvhich  are numerous in proportion to  the  size  of the
 organs. They commonly join those of the kidney.
              The Absorbents  ofthe 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 some 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 laminae 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.*
                    * See page 108. 
         Lacteals, or Absorbents ofthe Intestines.     389
   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 lamina;.
 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 theircourse frequently divide
 into branches; vvhich sometimes go to the same gland, some-
 times 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 fre-
 quently form three or four trunks, and sometimes one or
 two; which proceed in the course ofthe superior mesente-
 ric 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

       * They have been estimated between  130 and 150. 
 390          Absorbents ofthe Stomach.
 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
 the lacteals, quoted  in page 109,  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 ofthe 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
 caeliac artery.  The second  arise also on  both sides ofthe
 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 ofthe 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- 
                Absorbents ofthe Liver.            391
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.

              The Absorbents ofthe 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 ramifica-
tions; so that the  whole gland  has been injected from one
large vessel.
  The gland is so large, that the absorbents ofthe superior
and inferior surfaces proceed from it in different direc-
tions.
  A large absorbent is generally found on the suspen-
sory ligament.  This is  forme.d 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 interior to the xiphoid
cartilage, and then proceeds through glands on the anterior
part ofthe  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  vvhich 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- 
 392       Absorbents ofthe Liver and Spleen.
 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
 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 ofthe 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. 
      Absorbents ofthe Pancreas. Thoracic Duct.   393
  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
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; they 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 ofthe 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 ofthe pancreas.

              THE THORACIC DUCT,
Or common trunk of the absorbent system, is formed by
the union of those  absorbent vessels which are collected
on the lumbar vertebrae.
  These vessels, as it has  been already observed, are
derived from various sources, viz.
  Vol. II.                3 D 
394     Commencement ofthe Thoracic Duct.
   The Lower Extremities; the lower part of the Trunk of
the Body; the Organs of Generation; the  Intestines, with
the other Viscera ofthe abdomen and pelvis, except a part
of the liver.  Their number is proportioned to the extent
of their origin: for, with the numerous glands appropriated
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
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 vertebrae; 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 an-
gle 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 
           Termination ofthe Thoracic Duct.        395
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-
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 o f
the thorax; or when warm water is injected, either into the 
396           Absorbents ofthe Lungs.
bloodvessels of the lungs, or the ramifications  of the
trachea. Cruikshank demonstrated them by inflating the
lungs of a  still born child; in vvhich 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, vvhich 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.
  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 ofthe absorbents
of the right side.
                   CHAPTER II.

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

 1 HE 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, 
                  Glands ofthe Neck.              397
below and behind the mastoid process.  Sometimes there
are two or three on the check, near the basis ofthe 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.

                     SECTION I.
        Of the Absorbents ofthe Head and Neck.
  There is the greatest reason to believe that the brain
and  its appendages are supplied with absorbents like the
other parts.  Some of these vessels have been discovered
in the cavity ofthe 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 nume-
rous as  in other parts of the body. On the occiput they
pass down, inclining towards the ear, and continue be- 
 398       Absorbents ofthe Head and Neck.
 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, vvhich  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
 to the trunk of the absorbents on that side, near its termi-
 nation. It has been remarked that they can be readily in-
jected, by thrusting the pipe into the substance ofthe gland.

                    SECTION II.
   &fthe Absorbents of the Arm and Upper Part ofthe
                       Trunk.
  The absorbents of the arm are superficial  and  deep-
 seated, like those ofthe 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 
           Absorbents of the Hand and Arm.       399
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, vvhich 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 axillary
glands. There are generally one or more vessels vvhich
pass in the course of the cephalic vein, between the pecto-
ral 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 fingers,
and soon accompany the branches of the arteries.  Those i
which attend the radial artery, originate on the 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 ofthe fore arm.
  Those which attend the ulnar artery, commence under 
 400   Absorbents ofthe Upper Part ofthe Trunk.
 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 proceed
 to the axilla, and enter into the glands there; those which
 are deep-seated, joining the deep seated vessels. The ab-
 sorbents of the 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 number; they
 accompany the subclavian vein, and are reduced 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 ca-
vity 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. 
          Facts relating to Cutaneous Absorption.     401
     Two respectable physiologists of Europe (M. Seguin, of
       Paris, and the late Dr. Currie, of Liverpool)  have
       doubted whether absorption takes place on the exter-
       nal surface  of the skin.*—This question has  been
       examined in a very  interesting manner by several
       graduates ofthe university of Pennsylvania, who chose
       it for the subject of their inaugural 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
       commonly 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 ab-
       sorption took place. But  when they inspired air im-
       pregnated with exhalations from these substances, they
       perceived satisfactory proofs that the exhalations en-
       tered 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 exter-
       nal surface.
     On the other hand,  the  two gentlemen last  mentioned,
       state that after immersing themselves in  a bath consist-
       ing 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

  * 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 Medicine
Eclairee par les Sciences Physiques, vol. iii.—An extract from M
Fourcroy-*s  publication may be seen in the 19th chapter of the first
volume of Dr. Currie's " Medical Reports on the Effects of Water,"
&c, in which i*s also contained a statement ofthe Doctor's own expe-
riments and reflections.
  Vol. II.               3  F 
402  Experiments of K. Boerhaave and J. Hunter.
      articles is not volatile; and, therefore, could not have
      entered the lungs during the experiments.*
    The statement in page 380, 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.t
     About  the  middle of the last century, it was generally
       believed  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," 8cc,
       published at Leyden, 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 ramifications 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 experi-
       ments  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 ex-

  * The Thesis of Dr. Rousseau was published  in  1800.  Those o1
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. Soemmering's  valuable work on the
Structure ofthe Human Bod'v. 
           Experiments of Magendie and Delile.      403
       periments have  been  considered  as  establishing the
       fact, that absorption  (in the  intestines  at  least) is
       performed exclusively by the  lacteals, or proper ab-
       sorbent vessels, and not at all by the veins.  Kaaw
       Boerhaave is of course  supposed to have been mis-
       taken; and Mascagni,  who  has repeated  his experi-
       ment,  refers  the appearance of water 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. Magenjlie  and Delile,
       vvhich  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 inte-
       resting. 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 ap-
       plied 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 fromit, were divided,except one

  *  The title ofthe paper is a "Memoir on the Orgaiv*. of Absorption
in Mammiferous Animals." A translation of it was publishi d  in the
Medical and Philosophical Register of New York, and in  several cUkt
periodical works. 
40 1      Experiments of Magendie and Delile.
       artery and a vein.  A considerable 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 ofthe intestine and
       the rest of the body. Into the cavity of the intestine,
       which was thus circumstanced, 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
       ligatures 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 appli-
       cation  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 ques-
       tion v/hether this poison was taken up by the absorbents
       or by the veins.
    Some other experiments  made by  the authors gave re-
       sults, which are very difficult indeed to explain. They
       wished to know if the blood of an animal thus contami-
       nated, would produce similar effects upon another ani- 
           Experiments of Magendie and Delile.      405

       mal; 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  minutes after the introduction of the
       poison, they transfused blood from the jugular vein ofthe
       same side, into one ofthe veins of another dog. About
       one minute  after the commencement of the transfu-
       sion, the effects ofthe poison began in the dog to which
       it was applied, and continued until his death. Transfu-
       sion 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 producing any effect.—
       They varied this  experiment in the following manner.
       The thigh of a dog was separated from the body; the ar-
       tery and the vein were arranged as in the former expe-
       riment; and poison was introduced into the foot. Three
       minutes after the introduction of the poison,  the blood
       of the crural vein was passed into the jugular vein of
       another  animal,  and transfusion was continued  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 ofthe operation ofthe poison.*
    From these very interesting experiments the authors in-
       fer  that "foreign  matters do not always proceed through
       the Lymphatic or Absorbent  Vessels, when they enter into
       the  Sanguiferous system."

  * An  account of  these experiments was published by M. Magendie
mi 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
1811 In that statement this last mentioned experiment is omitted. 
40.6    Report ofthe Committee of the Institute.
    This memoir was referred by the Institute to four of its
      members, who are particularly distinguished  by their
      profound knowledge of anatomy and physiology. These
      gentlemen, after  stating their belief that the func-
      tions of the lymphatic or absorbent system have been
      completely ascertained by  the  experiments  and  ob-
      servations of Hunter, Cruikshank, Mascagni,  &c, say
      further, that, in their opinion, the above mentioned in-
      ference ought  to be a little modified, and that facts are
      not sufficiently numerous, or applicable to the point in
      question, to justify the inference  that foreign matters
      do not always  proceed through the Lymphatic or  Ab-
      sorbent Vessels, when they enter the Sanguiferous system.
      But they also add, that, as the author is still engaged
      in  a series of  experiments  on the subject, they will
      suspend their  judgment respecting the inferences to
      be deduced from the present statement.


    The  most extensive account of the absorbent system is
      contained in the '< Historia et Ichnographia Vasorum
      Lymphaticorum  Corporis Humani"  of  Mascagni.—
      " The Anatomy of the Absorbing Vessels of the Hu-
      man Body, by W. Cruikshank;"—and " The Descrip-
      tion ofthe Lymphatic System, by Wm. Hewson," (the
      second volume  of his Experimental Inquiries)—are also
      very interesting publications. 
SYSTEM OF ANATOMY.
APPENDIX. 
 
APPENDIX.
                  OP  THE BLOOD.


 1 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 which  thus appears upon the spontaneous
separation ofthe blood, is denominated Crassamentum 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 completelv
from the Crassamentum by washing it with water.
  Vol.  II.              3 F 
410           Appendix.—Of the Blood.
   The  blood, therefore, consists of three parts, viz. the
Serum; the Substance xvhich coagulates spontaneously; and
the Colouring Matter.

                      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 carried
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 coagulated.
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 ofthe muriate and the phosphate
of soda, and the phosphate of lime. These saline substan-
ces were discovered by diluting serum with water, and
exposing the  mixture to heat, by which the albumen was
coagulated into flocculae: these flocculae were separated
by filtration:  the liquor was then diminished bf evapora-
tion, 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-

  • See Hewson, Vol.  I. p. 139.—I suspect that some particular ma-
'■igement is necessary in the use of rennet. 
                Appendix___Of the Blood.            411
siderable quantity of gelatine; but it is contended by Mr.
Brande,* that Gelatine does not exist in the serum of the
Wood, and that this portion consists of albumen combined
with a proportion of alkali.
   It is also asserted by Dr.  Bostock,f 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 appears*]:

  * 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.
  t See his Observations on the Serum,of the Blood, in the Medic-a-
Chirurgical Transactions, Vol. II., republished in the Eclectic Reper-
tory, for October 1813.
  + By the experiments of Mr. Charles Hatchett, published in the
London Philosophical Transactions for 1800. 
412            Appendix.—-Of the Blood.
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
it has been obtained.  It is,  therefore, probable  that a
considerable proportion of the bulk of the crassamentum,
as 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  are  examined  with  magnifying
glasses, it  appears that the red  colour  of the blood is
owing to bodies  of a globular form, which are  diffused

  * 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. 1811—See also a  Treatise on the Blood, &c. by the
late J. Hunter. 
                 Appendix—Of the Blood.            413

through  a transparent fluid.  The  appearance  of these
bodies has been examined, with great attention,  by many
physiologists, since the publication of Leuwenhoeck, in the
London Philosophical Transactions.*
   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, f 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.

  * 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 London, for
1664, in the fasciculi which are numbered 102 and 106. A more full
description is contained  in Boerhaave's Academical Lectures on the
Theory of Physic.  See the section on the nature ofthe 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 ofthe transactions of that society.
  In the year 1798, Tiberius Cavallo  published  an Essay on the Me-
dicinal Properties of Factitious Air, with an appendix on the Nature of
the Blood;  in which is contained a further account ofthe glasses of De
la Torre.
  ■f I believe that  this is also the opinion of Fontana.—In  J. Hunter's
work on  the Blood there are some  interesting observations on micros-
copical deceptions. See  the note, commencing in page 39, Bradford's
edition. 
414           Appendix.—Of the Blood.
   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 inflammatory 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
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 sentiment.
In this account he stated, that, after washing the colouring
matter from the crassamentum, he had separated 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 magnet.
  After exposing a large quantity of the colouring matter
to an intense  heat, he found in  it a small piece of iron, of 
               Appendix.—Of the Blood.           415
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, &c. 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 on
this subject by several physiologists, and  especially by
Dr. Wells and Mr.  Brande.
  The first of these gentlemen, in his " Observations and
Experiments on the  Colour ofthe Blood,71 published in the
London Philosophical Transactions for 1797, states three
reasons for rejecting the opinion that the colour of the
blood is derived 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 an 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. 
 416           Appen dix.—Of the Blood.
   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
 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  gray  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
 physiologists have regarded them as fallacious. 
Appendix.—Structure of Glands.
417
                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 absorbent
 vessels, which are called the Lymphatic Glands;  but  it is
 most commonly appropriated to those organs vvhich dis-
 charge a fluid different  from the blood.
   The structure by which mucus is secreted  in some
 places, appears to be very simple. Thus in the Schneiderian
 membrane  and  the urethra, there are small ducts from
four to six  lines in length, and equal  in diameter to a
bristle, which appear to be formed of the membrane on
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
   Vol. II.              3 G 
418        Appendix.—Structure of Glands.
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
considered  as glandular, and  essential  to  the  mucous
secretion.
   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,
mammae,  &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 denominated Acini. Each of them is connect-
ed 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 exter-
nally, 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 incised  with  a sharp  instrument, ap-
pears differently; but when broken into pieces, it seems to
consist of small acini. Some other glands, as the Prostate,
appear to be uniform in their texture, and have none of
this granulated appearance. 
            Appendix.—Structure of Glands.        419
   The structure of glands has long been an interesting
object of anatomical inquiry,  and was investigated  with
great assiduity  by those  eminent anatomists,  Malpighi
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 mace-
rating 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 follicles or cavities in
glandular  bodies, which existed between  the extremities
of the arteries and the commencement of the excretory
ducts of those bodies, and that in these cavities the se-
creted fluids underwent a change.—Ruysch contended,
that the arteries of  glands were continued into excretory
ducts without the  intervention of any cavity or follicle;
that  the small  bodies, which had been supposed to  con-
tain  follicles or criptae, 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 Boerhaave
and  Ruysch in  the year 1721, and  are published at the
end ofthe fourth volume ofthe works of Ruysch.
  The opinion of Ruysch has been most generally adopted
by anatomists, and has derived support and confirmation
from  several anatomists since his time.—The late  Mr.
Hewson declared his conviction  that the small globular
bodies which are scattered through the kidneys, and were
supposed to be follicles or criptse, are merely convoluted 
420        Appendix.—Structure of Glands.
arteries. He also asserted, that the acini which appeared
in the mamma? 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 minute ramifications
of the excretory duct, vvhich  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 controvert-
ed by the Italian anatomist, Mascagni, who believes  that
the  arteries terminate only in veins;  and  of  course  that
they  neither form  exhalent  vessels, nor communicate
with  the  excretory ducts  of glands. His  idea  of the
structure  of glands  is different from those either of
Malpighi 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.
* See Experimental Inquiries, Vol. ii. p. 178. 
            Appendix.—Structure of Glands.         421
   In his great work on the absorbent system, when treat-
ing on the termination of arteries and the commencement
of veins, (Part I. Section 2.) he asserts, that if the kidneys
are successfully injected with size, coloured with vermi-
lion, and then laid open by a section 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 ves-
sels, originate from them.
  He  supposed  that a considerable portion of the fluid
thus passing off frofn the bloodvessels, is commonly taken
up by the absorbent  vessels of the kidneys: for in two
cases in which he found the absorbent vessels obstructed,
a diabetes existed, which he  considered as the effect of
the inactivity of the absorbents. He asserts, that  in the
liver, pancreas,  mamma?, and also in the  salivary 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 occu-
pied with microscopical observations, and has gone largely
into the discussion of this subject.*

  * The late Dr. W. Hunter, in his Medical Commentaries,  (p. 40,)
avowed his belief, that the fluids, which appear occasionally in the vari-
ous cavities ofthe body, transude through the coats ofthe bloodvessels.
Mr. Hewson (Experimental Inquiries, Vol. II. Chap. 7) suggested
several reasons for dissenting from this  opinion; but Mascagni has
rndeavoured to support it.—See a long note to the above mentioned
section of his work, page 74. 
422         Appendix.—Structure pf Glands.
    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
       necessary for the secretion of milk, when adipose matter
       appears to be produced by the mere membrane in which
       it is contained.
    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 de-
       pend  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 separa  ng from the blood
       the different 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.
                          A.

ACETABULUM. The cavity  which receives the  head of
  the thigh-bone; from acetum vinegar: so called, because it
  represents  the  acetabulum or saucer  of  the  ancients,  in
  which vinegar was held for the use ofthe table.
Acini.  From acinus a grape.
Acromion. A  process of the scapula;  from  «*:••«-• extremity,
  and ufia the shoulder.
Anastomosis. The communication of vessels with one another;
  from um through, and rop* a mouth.
Anatomy. The dissection of the human body; from «»-*, and
  rtftt* to dissect.
Anconeus. A muscle; so called from *y*«» the elbow.
Aorta.  Aoprvi; from «»jg air, and ri-giw to  keep.
Aponeurosis. A tendinous expansion; from «*•••. and nvfi a
  nerve;  from an erroneous supposition  of the ancients, that
  it was formed by an expansion of nerve.
Apophysis. A process of a bone; from cmtpvu to proceed from.
  A synonyme of process.
Arachnoides. A net-like membrane; from stftc^n a spider, and
  uhs likeness.
*  By Dr. Hooper. 
 424                 GLOSSARY.
 Artery. From *«•> air, and t-*i-*8« to keep; because the ancients
   supposed that air only was contained in  them.
 Arthrodia. A species of connexion of bones; from upDpav to
   articulate.
 Arytanoides. The name  of two cartilages of the larynx; also
   applied to some muscles ofthe larynx; from xpvTxtta a fun-
   nel, and ttSbf a shape.
 Astragalus. A bone of the tarsus; so  called from  its resem-
   blance to a die used in ancient games, from ct,?rxy«,Xos a
   cockal or die.
Atlas. The first vertebra of the neck; so called, because it sus-
   tains the head: from the  fable of Atlas being supposed to
   have supported the world; or from utXum to sustain, because
   it sustains the head.
Azygos.  A term applied to parts without a fellow, from «
   priv. and £t»y«5 a yoke,  because it has no fellow.

                           B.
Bursa. A bag; from /Svpr*: generally applied  to the bursa?
  muscosae.
                           C.
Cancelli. Lattice  work;  generally applied to the  recticular
  substance in bones.
Cardia. The superior opening ofthe stomach; from x.»ph«, the
  heart.
Carotid. The name  of some arteries  of the neck and  head;
  from x*fow to cause to sleep; for, if tied with a ligature, the
  animal was said to be affected with coma.
Carpus. Kaf7r»s;  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 ofthe sella turcica of the ethmoid bone
  are so called, from **m a bed, and e-^j likeness; from  their
  supposed resemblance  to a couch. 
                      GLOSSARY.                 425
 Clitoris. A part of the female pudenda, enclosed by the labia
   majora; from xXuu to enclose or hide.
 Cdlon. The first ofthe large intestines; from xmtei, quasi xotX**,
   from MiXa hollow.
 Coracoid. From  xt»*\ a crow, and »S«$ resemblance; shaped
   like the beak of a crow.
 Coronary. From  corona a crown. The vessels of the heart,
   stomach, &c. are so called because they surround the parts
   in the manner of a crown.
 Cotyloid. From xtrvXn the name of an old  measure, and  uht
   resemblance; resembling the kotule.
 Cranium. The skull;  xgccm»>, quasi xxgemtr, from ««£« the
   head.
Cremaster.  A muscle so called; from xttftxu to suspend, be-
   cause it suspends the testicle.
Cribriform. From cribrum a sieve, it being perforated like a
   sieve.
Cricoid. Annular, round, like a ring; from  xpx«s a ring,  and
   uSof likeness.
Cuboides. A bone of the foot; from xvZct a cube, and ulee like-
   ness; 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 A,
   and t-3e; resemblance.
Diaphragm. The muscle which separates the thorax from the
   abdomen; from tuxVexrl* to divide.
Diarthrosis. A movable connexion of bones; from  ti»^tt«m to
  articulate.
Digastric. From  Sis twice, and  y«*r«{ a belly; having  two
  bellies.
Diploe. The spongy substance between the two tables of the
   skull; from 3iwA«* to double.
  Vol.  II.                3H 
 426                  GLOSSARY.
 Duodenum. The first portion ofthe small intestines; so called
   because  the ancients supposed that it did not exceed the
   breadth  of twelve fingers; from duodenus, 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 fcetus; from tp&fvo to bud
   forth.
 Enarthrosis. An articulation of bones; from t»in, and  «£■*»•><» a
   joint or articulation.
 Enteric.  Belonging to the intestines; from tweet an entrail or
  intestine.
 Epidermis. The scarf or outermost skin; from  %m upon, and
   hym the skin.
 Epididymis. The small oblong body which lies above the tes-
   ticles;  from t7ct upon, and hhfcts a testicle.
 Epigastric. The superior part ofthe abdomen; from ««•/ upon,
   and yafug the stomach.
 Epiglottis.  A cartilage of the larynx so called;  from tin upon,
   and yXarlis the aperture of the larynx,  being  situated upon
   the glottis.
Epiphysis.  A portion of  bone  growing  upon another bone,
   but separated from it by a cartilage: from e-r< upon, and <pv*
   to grow.
Epiploon. The membranous viscus of the abdomen, which
  covers the intestines, and hangs to the bottom ofthe stomach;
  from mnrMu to swim upon.
Ethmoid. From t9ft»t a sieve, and uhs resemblance; being per-
   forated like a sieve. 
GLOSSARY.                 427
                            F.
 Fascia. An expansion, enclosing  other parts, like  a band;
   from ./-asm a bundle.
 Falciform. Shaped like a scythe; from falx a scythe.
 Fasctc&lus.  A little bundle, dim. offascis a bundle.
 Fauces. The plural of faux, the top of the throat.

                            G.
 Ganglion. r*fyxt*>, a knot in the course of a nerve.
 Gastrocnemius. The muscle which  forms the thick of the leg;
  from yxrne a belly, and xtnftv the  leg.
 Geriio. Names compounded with this word belong to muscles
  which  are attached to the chin, as genio-glossus—genio-
  hyoideus, Sec; from yivuo» the chin.
 Ginglymus.  An articulation; from y.fyAv^o? a hinge.
 Glenoid cavity.  From yXwn a cavity, and  uhs resemblance.
 Glosso. Names compounded with this word belong to muscles
  which are attached to the tongue; as glosso-pharyngeus—
  glosso-staphilinus, &c; from yXarrx the tongue.
 Glottis. The superior opening of the larynx at the bottom of
  the tongue; from yXairl* the tongue.
 Gluteus. The name of a muscle; from yA«r«<- the buttocks.
 Gomphosis.  TeftQuns, a species  of  immovable connexion of
  bones;  from y**.^**** a nail,  because one bone is fixed in
  another bone like a nail in a board.

                           H.
H^lix. The outward circle of the ear; from uXu to turn about.
Hepar. The liver, 'h-ts*** an abdominal viscus.
Hyaloid. From lxXt% glass, and «}«; likeness; the capsule ofthe
  vitreous humour of the eye  is so called, from its transparent
  and glassy appearance.
Hymen. The membrane situated at  the entrance of the virgin
  vagina; from "tfwi Hymen, the god of marriage. 
428                 GLOSSARY.
Hyoides. A bone of the tongue, so called from its resemblance
  to the Greek v; from v, and i«3l»f resemblance.
Hypochondrium. That part of the body which lies under the
  cartilages of the spurious ribs; from vtr« under, and x**t[»i
  a cartilage.
Hypogastric. The lower region ofthe fore part ofthe abdomen;
  from vn under, and y«j->--> the stomach.

                           I.
Ileon. A portion of the  small intestines; from uXw to turn;
  being always convoluted.
Ischium. The part of the os innominatum upon which we sit;
  from irx,vu to sustain.

                           L.
Lacuna. The excretory duct of the glands of the urethra and
  vagina; from lacus a channel.
Lambdoidal  suture.  So called because  it is shaped  like the
  letter x; from x, and uh?  resemblance.
Larynx. The superior part of the windpipe; x*fvy\ the larynx.

                          M.
Masseter. A muscle of the face, which assists in the action of
  chewing} from ftxarxe/ixt  to chew.
Mastoid. From pxret a breast, and ut*f likeness;  shaped like
  a nipple or breast.
Mediastinum. The production ofthe pleura, which divides the
  thorax into two cavities;  from medium the middle, quasi in
  medio stare.
Mesentery. The membranes to which the intestines are attach-
  ed; from ptr»s the middle, and ttrtfer an intestine, because it
  is in the middle of the intestines.
Mesocolon. That part of the mesentery  in the middle of the
  colon; from puree the middle, and xeXtt the colon. 
                       GLOSSARY.                  429
 Metacarpus. That part of the hand between the carpus and
   fingers; from pir* after, and xxpxes the wrist.
 Metatarsus. That part of the foot between the tarsus and toes;
   from furx after, and rxpres the tarsus.
 Mylo. Names compounded  with  this word belong to muscles
   which are attached near the grinders, as mylo-hyoideus, &c;
   from ftVxv a grinder tooth.

                            O.
 Odontoid. Tooth-like; from •!»$  a tooth, and uh( resemblance.
 Esophagus. The canal  leading from the pharynx to the sto-
   mach; from 010 to carry, and <pxyt> to eat; because it carries
   the food into the stomach.
 Olecranon. The elbow, or head of the ulna; from uxm the cu-
   bit, and xpxvoi the head.
 Omentum.  An abdominal viscus;  so called from omen a guess;
   because 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, &c. from
   m/*«t the shoulder.
 Omoplata. The scapula or shoulder-blade; from «/t«$ the shoul-
   der, and v-Xurvf broad.
 Osteology. The doctrine of the bones; from erttr a bone, and
   A«y«t a discourse.

                           P.
Pancreas. A viscus of the abdomen;  so called from its fleshy
   consistence; from -axi all, and xptxg flesh.
Parenchyma. The substance of  some of the viscera was so
   called, from zrxftyxv* to pour through.
Parotid Gland; from wxpx near, and «v; the ear; because it is
   situated near the ear.
Pelvis. A bony cavity shaped like a bason; from mXvs a bason.
Pericardium. The membrane which surrounds the heart;  from
  wtpt around, and xxfttx the heart. 
  430                 GLOSSARY.
  Pericranium. The membrane which covers the bones of the
    skull; from nipt around, and xpxnei the cranium or head.
  Periosteum. The membrane which surrounds the bones; from
    vtpt around, and es-tev a bone.
  Peristaltic  motion of the intestines; from -zrtpirtxxu,  to con-
    tract.
  Peritoneum. The membrane lining the abdomen, and covering
    its viscera; from viptrtna to extend around.
 Phalanx. The bones ofthe fingers and toes are called phalanxes,
   from their regular situation, like a <p*x*y%, or arrangement
   of soldiers.
 Pharynx. A membranous bag at the  end of the mouth; «to t*
   <ptpu», because it conveys the food into the stomach.
 Phrenic or diaphragmatic nerve. <tywis  the diaphragm; from
   tppw the mind, because the ancients  supposed  it to be the
   seat ofthe 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; vXtvpa the side.
 Plexus. A kind of net-work of vessels or nerves; from plecto
   to weave together.
 Psoas. A muscle so called; from $ex the loin, being situated
   in the loins.
 Pterygoid process.  From zrltpv% a pen or  wing, and »}«$ like-
   ness; so called from its likeness to a pen or wing.
 Pylorus. The lower orifice of the stomach, which opens into
   the intestines; from wXov to guard an  entrance, because it
   guards as it were the entrance  of the bowels.

                           R.
Raphe. A suture; from pW7<y to sew.
Renes. The kidneys, xko tk put, because through them the urine
  flows.
Retina. The net-like expansion ofthe optic nerve, on the inner
  surface of the eye; from rete a net. 
GLOSSARY.
431
Rhomboides. A muscle  so  called from its shape;  from pepZeg
   a geometrical figure, whose sides are  equal but not right-
   angled, and 1*9-0; 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; »iro t* rem 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 rxxfn a little boat or skiff.
Scaphoides.  A bone of the  carpus, so called from its resem-
   blance to a skiff; from o~xx<pn a  skiff, and Ǥ*5  likeness.
Sclerotic. A term applied to the outermost or hardest membrane
   ofthe eye; from o-xXnpeu 'o make hard.
Sesamoid bones. From mo-xftt) a grain, and u^og a likeness; from
  their resemblance to the  semen sesami.
Sigmoid. Parts are so called from their  resemblance to the
  letter £; from  S, the letter Sigma, and  u^os likeness.
Sphenoid. From  e-Qn* a wedge, and u$$s likeness; shaped like
  a wedge.
Sphincter.  The name of several muscles whose office is to shut
  up the aperture around which they are placed; from rfp,yy«
  to shut up.
Splanchnic. From o-xXxy%io, an entrail.
Symphysis. A connexion of bones; from  rvptQw to grow to-
  gether.
Synarthrosis. A  connexion of bones; from <?«•# with, and xplp«t
  a joint. 
 432                  GLOSSARY.
 Synchondrosis. A species of union of bones by means of carti-
   lage; from o-»v with, and •^•rSj>«; a cartilage.
 Synneurosis.  A species of connexion of bones by means of
   membrane; from o~vi with, and nvpet a nerve; because mem-
   branes, ligaments, and tendons, were by the ancients con-
   sidered as nerves.
 Syssarcosis. A species of connexion of bones by means of
   muscle; from <rw with, and rxp\ flesh.
 Systole. The contractile motion of the heart and arteries; from
   #-#«aa«- to contract.

                           T.
 Tendon. From rum to extend.
 Thorax. ®»px\. The breast or chest.
 Thyroid. From Svput a shield, and tiles likeness; shaped like a
   shield.
 Trachea. The windpipe, so called from its  roughness;  from
  rp*x,vf rough.
 Trochanter. A process ofthe thigh-bone, so called from rp*x*t
  a wheel.

                           U.
 Ulna.  A name for the cubit; from uXtvn the cubit.
Ureter. The canal vyhich conveys the urine from the kidney to
  the  bladder; from upei urine.
 Urethra. The passage through which the urine passes from
  the  bladder; from gptr the urine.
Uvea.  The posterior lamina of the iris, so called because in
  many animals it is ofthe colour of unripe grapes; from uva
  an unripe grape.
Uvula. The conical 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. 
GLOSSARY.
433
                          V.
Valves. From valva folding doors.
Vertebra. The bones of the spine are so called; from verto to
  turn.
                          X.
Xiphoid. So called from the resemblance to a sword; from %t^
  a sword, and tfl,s likeness.

                          Z.
Zygdma. The cavity under the zygomatic process of the tern-  .
  poral bones; from £**y«? a yoke.
Vol. II.              3 I 
 
INDEX.
                             A.
                                             Vol. I.       Vol. II.
 a                                           Page         Ffcge
Abdomen......          .  .        83
Abernethy, Mr. statement by him in the London
                  Philosophical Transactions        ...     59
                case of termination ofthe vena
                portarum in the vena cava be-
                low the liver   ...          ...    140
              description by, of the mesenteric
                  gland ofthe whale     ;          .... 381
Absorbent vessels.....          ...    377
              of the lower extremities              ...    382
              ofthe head and neck                 ...    126
              of the abdomen and thorax            .  .   .    397
              ofthe arm and upper part of
                  the trunk    ...          ...    398
Acetabulum.......104  .  .   .
Accessory nerve of Willis  ....          ...    346
Acini ofthe liver......          ...    133
Adhesion of the lungs to the thorax   .    .          .  .   .     73
Adipose artery......          ...    283
        membrane.....401  .  .   .
Adjustment ofthe center of gravity        •     307  .  .   .
Alphabetical arrangement of the muscles   .     265  .  .   .
Alveolar artery......          ...    250
Anastomotic artery.....          ...    295
Andre, M.St.......413  ..   .
Animal motion, question respecting             1,68  ..   .
Aorta........          •••    238
      table ofthe, exhibiting the distribution
        of its branches     ....          ...    300 
436
INDEX.
                                             Vol. L          Vol. II.
                                             Page           Page
 Appearance of the caecum and colon  .    .           ...     119
 Appendix ofthe diaphragm      .               210  .  .  .
 Aqueducts of the ear.....395  .  .  .
 Aqueous humour      .....370
 Arbor vitae.......332
 Arm, bones ofthe.....115
      nerves of the.....          ...     353
 Arrangement of the jejunum and ileon     .           ...     116
 Arteries, general account of their distribution          ...     238
 Articulations, general account of .     .    .     273
 Astragalus.......151
           articulation ofthe    .         .      295  .
 Auditory nerve......394
 Auricular artery......                    94*
 Axillary artery......           #         264
        vein......           ...    311
 Azygos, vena......           ...    304


                               B.
Baillie, Dr.        ......                     _~
Ball ofthe eye......349
Barclay, Dr.......           ...    263
Basilar artery......                    2fii
Basilic vein  .......                    311
Basis ofthe cranium.....62  .
           brain     .....     333  ..  .
Baynham, Dr. of Virginia, his method of in.
  jecting the rete mucosum ....     408
Bell, C.      ......     371   .  .'
Bell, John, observation of   ...                        ...
Berlin, royal academy of sciences of   .    .     415
Berzelius, professor of chemistry at Stockholm,
      his experiment on secretion    .    .                    42g
Bichat, M. opinion embraced by, respecting
            the extent of the retina  .     .     364
          ofthe pores ofthe cuticle       .     416  .
          doubts of, the existence of the rete
            mucosum in the tongue  .                         21 
INDEX.
437
                                             Vol. I.         Vol. II.
  .                                            Page           Page
Bichat, M. his solution of a problem   .     .          ...     74
          doubts of, respecting the muscula-
             rity of arteries     ...          ...    230
          on the structure of arteries                 ...    230
Biliary duct.....         .          ...    140
Biliary and pancreatic ducts, orifices of  .   .          .  .  ,    114
Bile........          ...    142
Bladder, gall......                    j4q
         urinary......          ...    164
fllood   •••..,..          ...    409
      colouring matter ofthe    ...          .  :  .    412
Bloodvessels in general      ....          ...    224
            of the tongue  ....          ...      23
            ofthe abdomen     ...          ...     88
Boerhaave, K. experiments of                        ...    402
Bones, structure of             .     .     .       1  .   .  .
       formation of.....       5  .   .  .
       terms used in the description of     .       6  .  .  .
Bostock, Dr.......          ...     .71
          his assertion respecting tb/2 blood          .   .  .     4H
Boyer, M........          ....     169
Brachial plexus of nerves   ....          ...     352
                       construction ofthe           .   .  .     353
Brande, Mr. on the serum ofthe blood                 ...     411
           his chemical researches respect-
              ing the blood     ...          ...     416
Brain, basis of    .....    .     333  .   .  .
      commissures of      ....     329  .   .  .
      middle artery of     ....          ...     257
      nerves  of......333  .   .  .
Irtish anatomists on the spleen  .     .     .          ...    153
Brodie on the source of motion in the heart           ...      82
Bronchiae, black glands on   ...               ...      64
Bronchial artery......          ...    274
Bucquet, M.      ......          ...    415
Buisson, M.      ......          ...     345
Burs* mucosae             .               275.303  .   .  . 
438
INDEX.
			Vol. L			V61. II.
Page Page						
c						
Caecum........ ... 119						
position of .						120
Camper ....						220
Canals, semicircular			392			
Capsular arteries						283
veins						315
Cardiac plexus						372
Carlyle, Dr.			163			
Carotid arteries						240
Carpus ....			125			
Cauda equina			340			
Cavallo, Tiberius						412
Cavities of the nose			56			
Cavity of the cranium .			59			
tympanum			379			
Cellular membrane			398			
Cerebellum			332			
Cerebrum			321			
Cephalic vein						311
Change of colour in negroes, instance of 410						
Changes ofthe rete mucosum in white						
persons.......411						
Change of position in the stomach						
Choctaw Indians, custom of 66						
Chorda Tympani		386 .				
Choroid coat		353				
Ciliary ligament ....		355				
processes		360 .				
Circulation in the placenta, objects of the						222
Circumflex artery of the os ilium						292
vein......						318
Clavicle . . ... . 109 .						
Coat ofthe liver......						138
Cochlea.......390						
Colon, structure of.....						120
valve ofthe.....						122
Cooper, Mr. Astley ""?....						85
Cornea	.		351			
 
INDEX.
439
                                              Vol. I.         Vol. II.
                                              Page           Page
Coronary veins......           ...     302
Corpora albicantia of Willis      .     •          334  .   .  .
Corpora cavernosa     .     .     :     .    .           ...     187
                  cells ofthe    ...           ...     188
         lutea......           ...     211
C#pus spongiosum.....           ...     190
                  structure of                       ...     1S1
Corpsucula Arantii......           ...      55
Crassamentum    ...'...           ...     411
Cremaster muscle.....           ...     176
Cricoid cartilage   .......           ...      51
Cruikshank, Mr. Wm. his opinion respecting
              the vessels between the rete
              mucosum and cutis   .    .   406,409  .  .  .
            his experiments favourable to the
              idea of the motions of the heart
              being independent of the brain          ...     80
            his ideas relative to the origin of
              the lacteals      ...                109, S79
            his description ofthe appearance of
              the absorbents of the kidney            .  .   .    387
            his injection of the absorbents of
              the pancreas       .      .           ...    393
            his demonstration of those of the
              lungs   .....           ...    396
Crural nerve......           ...    361
Crystalline lens......368   .  .   .
Cubital nerves    ......           ...    349
Currie, Dr. (of Liverpool)   ....           ...    401
Cuticle.......413   ..   .
Cuticle, pores of......414   .'  .  .
        peculiar permeability of .              415   ,  .  .
        separation of the    ....     418
        chemical qualities of the      .   .     419   .  .   .
Cuvier, M.  his opinion respecting the vascular
            convolutions ofthe corpus spongi-
            osum of the horse        ._              ...    199 
440
INDEX.
                                             Vol. I.
                                              Puge
                              D.

Daingerfield, Dr. his experiments
Delile, M. his memoir on the organs of absorp-
          tion in mammiferous animals
Desault, M. his ideas respecting the structure
          ofthe spleen    ....
        his experiment respecting the frontal
          sinus   ....     .
Diaphragm.......210
          nerves ofthe    ....
Digital arteries......
Dorsal nerves    ......
Dorsey, Dr. John S......
Duct, thoracic.....
      hepatic......
      cystic......
Ductus venosus   ......
Duodenum       ......
Dupuytren, M. inference from his statement in
            a volume ofthe proceedings of the
            National Institute, respecting the
            nerves ofthe lungs  .
Dura mater       ......3.I5
Vol. II.-
 ***

  401

  403

  152

   13

  351
  272
  357
   73
  393
  136
  140
  221
  313
73
Ear . .... bones ofthe ....	374 . . 383 . .	
Ellis on respiration Elbow, articulation ofthe	284 . .	71
Emulgent arteries		283
veins .... Epidermis ..... Epididymis..... Epigastric artery	413 .. .	315 179 279
vein .... Epiglottis...... Eustachian tube ....	382 . .	318 30
Fxternal pudic arteries		293
 
INDEX.
441
External iliac arteries
         iliac veins
Eye, description ofthe orbit of the
     parts auxiliary to the
     ball ofthe    ....
     humours of the
     dissection of the
     effect ofthe solution of nitrate of silver
       on the hyaloid coat of the
Vol. I.
Page
 54
343
349
365
371

373
F.
Face ....		33
Facial artery ..... Fauces, isthmus of the		
Fallopian tubes, structure ofthe		
Falconer, Mr. on the spleen		
Falx.......		318
Femoral artery		
vein		
Foetus, head of		67
thorax of		69
trunk of		106
extremities of .		160
Fibula	•	145
Fimbriae		
Fingers articulation of the		136 288
Foot . . ...		149
Fontana Abbe . . . . on the structure of the nerves on the colour ofthe blood		158
Foramen caecum lacerum . ovale thyroideum Forearm interosseous ligamen Vol. II. 3	tof the . K	23 63 53 103 120 297
 
442
INDEX.
Fornix
Fossa ovalis     ....
Fourcroy, M.
French anatomists, their peculiar opinions
  respecting the course of the blood in the
  fcetus......-»
Fyfe, Mr. on the villi    ....
Vol.1.	vol. n.
Page	Page
326 .	. .
79 .	.
401
 75
110
G.
Gall, Dr.	338 .	
Ganglions		. . 325
Gastric liquor		. . 103
Gavard, M. proposition of	-	118
Generation, female organs of		. . 200
male organs of		. . 173
Glands inguinal		. . 384
Glands on the bronchiae		. . 64
ofthe mesentery		. . 118
ofthe neck		. . 347
Glandulae Buccales		. . 15
Brunneri		. . 107
Peyeri		. . 107
Molares	.	. . 257
Renales		156
Gluteal artery		289
Goodwin, Dr. his explanation of the effects of		
venous blood on the heart		74
Graff De, his successful investigation of the		
testicle ....		. . 182
Grew, Dr. ....	414 .	
H.
Haighton, Mr. a dissection ofthe ear record-		
ed by	397 . .	
essay of ....	. .	37
Haller, M. on muscular fibres	163 . .	,
remarkable sentiment of	,	42
 
INDEX.
443
                                               Vol. I.         Vol. II.
                                               Page          Page
 Haller, M. inclined to the opinion of Ruysch on
              the spleen     .     .    .               . •.  .    152
            a cavity in the glandula renales fre-
              quently found by                        ...    157
            his publication in the Philosophical
              Transactions of London  .    .           ...    182
            on the testicles of the foetus                 ...    220
            his great  attention to the arterial
             system.....           ...    263
            his observations  on  the absorbent
             vessels.....           ...    378
 Hand........125   ..   .
 Hatchet, Mr. Charles.....           ...   411
 Heart, description of the    ....           ...    50
 Hepatic artery......           ...   278
        veins......           ...   314
 Hewson, Mr. William, on the Villi                   ...   1Q9
                 his opinion respecting the
                   spleen   ....           ...   153
                 on serum  ....           ...   41Q
                 on the crassamentum                ...   412
                 on the colour of the blood            . .  .   414
                 on the structure of glands            .  .   .   420
 Hewson, Dr. T. T. his experiments on the blood       .  .   .   412
 Home, Mr.  Croonian lectura of                 168  .  .   .
           his assertion respecting the mem-
              brana tympani     .         .     381  .  .
           confirmation of the account of the
              vesicles in the spleen   .    .           ...    154
           his questions relative to the blood          .  .   .    422
Hottentots, female, peculiarity of the                   ...    217
Humboldt, M. on the experiments of Legallois         ...     81
Humeral artery......           ...    267
Hungarians, peculiarity of the    ...           ...    226
Hunter, Dr. William.....401  ..   .     73
             opinion of, on the villi   .                ...    109
             his opinion respecting the struc-
              ture  of glands       .      •           ...    420
             belief respecting a part  in glands
              not injected in his preparations            .  .    420 
444
INDEX.
                                             Votl.         Vol. li.
                                              P»ge          Page
Hunter, Dr. William, his idea of fluids which
                   appear in the various cavi-
                   ties of the body   .     .                .421
Hunter, Mr. John      .....                 103,185
            his opinion respecting the vascular
               structure of the corpus spongio-
               sum urethrae ....           ...    199
            fact established by experiments of        ...    403
            on the structure of arteries               ...    229
            on the colour of the blood     .           ...    413
Hypogastric artery.....           ...    286
            vein       ....                ...    317



Iliac arteries......           ...    285
     veins.......           ...    317
Injected preparations, examination of                 ...    273
Instances of peculiar arrangement of veins             .  .  .    320
Intercostal arteries.....           ...    275
           veins        .....           ...    305
Interosseal artery.....           ...    271
Internal basis of the cranium                     59  .  .  .
Intestines    ...'....           .... 106
         division of.....           ...    Ill
Iris     ........356  ..  .
Ischiatic artery......           ...    289
Jejunum and ileon.....           ...    114
Jones, Dr.       .......           ...    230
Jugular veins, internal      ....           ...    307
             external      ....           ...    309
Jussieu, M. account by, of a female born with-
             out a tongue  ....           ...     28

                               K.

Kidneys.......           ...    158
         cortical and tubular portions of the            .   .   .    161
         nerves, lymphatics, and coat ofthe            .   .   .    162
         absorbents ofthe    ....                     337 
INDEX.
445
                                            Vol. I,         Vol. II.
                                             Page          Page
Klapp, Dr........                   401
Knee, articulation of the        ...     291

                              L.
Labia externa.....                        201
Labyrinth.......388  ..  .
          contents of the       .     .    .     393
          functions ofthe different parts of     396  .   .  .
Laennec, M.......          ...    13S
Lachrymal gland     .....346  .   .  .
          sac......347  .   .  .
Lacteals.......          ...    388
Larynx       .......          ...     31
Legallois, M. experiments of, on the source of
              the motion ofthe heart               ...     80
Lieberkuhn, M.......          ...    108
Lieutaud, M.......          ...    169
Ligaments   ......     297  .   .  .
Liver........          ...    129
      absorbents ofthe     ....          ...    391
Lumbar arteries......          ...    285
        veins......          ...    316
        nerves......          ...    359
        plexus......          ...    360
Lungs,.......          ...     65
      structure of.....          ...     67
      absorbents of.....          ...    395
Lymphatics in the spermatic cord                    ...    177
           ofthe uterus   .    .                   ...    213

                             M.

Magendie, M. experiments of,  on the organs of
                  absorption  in mammiferous
                  animals     ...          ...    403
Malformation, cases of     .....          ...     72
Malpighi, M. on the structure ofthe spleen           ...    149
             on the structure of glands              .   .  .    419
Mammary artery      ....                   .    259 
446
INDEX.
	Vol. I.	vor. ir
	Page	Page
		. . 73
Mascagni, M. on the villi ....		. . 110
on the absorbents ofthe kidney		. . 387
assertion of, in his great work		
on the absorbent system		. . 421
his ideas respecting the structure		
of glands ....		. . 420
Mastoid cells......	382 .	
Maxilla inferior .... . .	44 .	
Maxillary arteries.....		. . 244
nerves .....		. . 333
Meatus Auditorius Externus	377 .	
Internus	392 .	
Meckle, Professor, his opinion respecting the		
outlets of perspiration .	415 .	
on the nerves of the face		. . 342
Mediastinum......		
Median nerve......		. . 354
vein......		
Meibomus, glands of.....	346 .	
Membrane, adipose.....	410 .	
Schneiderian ....	5 .	
extent of	0 . .	
distribution of :	10 . .	
Membrana tympani.....	380 . .	
observations on the	387 . .	
Menghini, Vincentius, his experiments tend-		
ing to establish the opinion, that the colour		
ofthe blood depends upon iron		414
Mesentery.......	116 . .	
construction of ... .	117 . .	
root of.....	118 . .	
Mesenteric artery.....		282
vein......		315
Metacarpus ......	131 . .	
Metatarsus.......	156 . .	
Middle haemorrhoidal vein ....		288
sacral vein .....		316
Monro, Dr. on the Bursae Mucosae	275 . .	
on the iris . .	359 .	
 
                           INDEX.                       447
                                             Vol. I.         Vol. II.
                                             Page          Page
Monro, Dr. opinion of, respecting the extent of
             the retina    .    .    .     .      364  .  .  .
          his opinion respecting the villi              ...    109
          observation of, on the epididymis           ...    182
Morgagni, M. ventricle of  ...               ...     34
Motion, muscular, phenomena of     .    .      166  .  .  .
        of the skeleton     ....      167  .  ...
Mouth       .......           ...     14
      internal surface ofthe     ...           ...     15
Mucus of the nose.....           ...     13
       ofthe bladder      .                         ...    168
Mussey, Dr.               ....           ...    401
Muscles, alphabetical arrangement of            265  .  .   .

                              N.

Nails.....,    .     .      419  ..   .
Neck, arteries of the       ....           ...    263
      absorbents of the     ....           ...    397
      muscles ofthe.....219  .  .   .
Nerves, general account of       ...           ...    323
Nichols, Dr. F.......           ...    153
Nose........           ...      1
      cavities ofthe.....       56  .  .  .      5
      nerves of   .    :                             ...      8
      sinuses of       ...                    ...     13

                              0.
Obturator artery  ......           .  .   ,    288
Occipital artery        .....           ...    246
Oesophagus      ......           ...     95
Olfactory nerve.....'           ...    328
Omentum, origin and arrangement of      .           ...    127
          varieties in the appearance of              ...    128
Ophthalmic artery.....           ...    254
           nerve.....           ...    332
Ovaries.......           .  .   .-    210
Os frontis.......       14  .  .   .
Ossa parietalia    ...■••       17 
  448                      INDEX.
                                              Vol. I.         Vol. U.
                                              Page          Page
  Ossa temporum......      18  .   .  •
  Os occipitis  .......      22  .   •  •
  Os ethmoides......24  .   .  •
  Os sphenoides    .    .    .    .  "*  .    r      28  .   .  •
  Ossa maxillaria euperiora   .     .    .    •      34  .   .  ■
  Ossa nasi.......      37  .   .  ■
  Ossa unguis      .    ,    .    .     .     .      38  .   .  .
  Ossa malarum......      39  .   .  •
  Ossa palati.......      40  .   .  .
  Ossa spongiosa......      43  .   .  .
  Os hyoides        ......      52  .   .  .
v Os sacrum.......      84  .   .  .
  Os coccygis       ......      86  .   .  .
  Os ilium.......      99  .  .  .
  Os ischium        .......    100  .   .  .
  Os pubis     .    .    .    .     .    .    .    102   ..  .
  Os humeri        ......115  .  .  .
  Os femoris.......139   .  .  .
  Os calcis.......151  .   .
  Os naviculare......153   .  .  .
  Os cuboides      ......153   .  .  .
  Os cuneiforme......154   .  .  .

                                P.

  Palpebral.......344   .  .  .
  Pancreas     ....        .               ...   144
  Pancreatic duct        .....          ...   145
  Pancreas enlarged, symptoms of      .     .           ...   146
  Papillae of the tongue.....           ...     22
  Far Vagum.......          ...   343
  Parotid gland......          ...     25
  Patella.......          147  .  .  .
  Pears, Mr. C. account by, of a woman in whom
     the ovaria were deficient     ...          ...   216
  Peculiarity of the liver     ....          ...   139
  Pelvis........      98   .  . .
       ligaments ofthe      ....     299   .  .  .
       absorbents of the    ....           ...   387 
INDEX.
449
Perforating arteries
Pericardium
Peritoneum
Periosteum
Peroneal artery
         nerve
Pharyngeal artery, inferior
Pharynx, structure of the
Phrenic artery
        vein
Physick, Dr.  his opinion respecting incisions
   ofthe cornea......
Pia mater
Pineal gland
Pleura, arrangement of the
Plexuses of nerves
Plexus choroides
Pomuin Adami
Popliteal artery
Pores ofthe cutis vera
Portarum vena
Portio Dura
Posterior iliac artery
Poupart's ligament, method of preparing it for
            examination
Priestley, Dr.
Primitive iliac arteries
              veins
Provencal,  Dr. J. M.
Pudic artery
Pulmonary  arteries and veins
           plexus
Puncta Lachrymalis
Pylorus      ....

                               Q.

Questions, respecting perspiration
                the structure of the spleen
Questions of Mr. Home
   Vol. II.
Vol. I.
 Page
352
317
330
327
405
200
347
415
154
422
3 L 
450                       INDEX.
                                              Vol I.         Vol.II.
                                              Page           Page
                               R.

 Radial artery     .....               ...    269
       nerve......          ...    356
 Radius........122  ..   .
 Reticular membrane.....401  .   .   •
 Reaumur, M.......          ...    10S
 Rectum, position and structure of                    ...    124
 Renal arteries......          ...    283
 Reproduction of nerves      ....          ...    327
 Rete mucosum......408  .   .   .
 Retina.......363  ..   .
 Ribs........      88  .   .   .
 Ridley, circular sinus of    ...          320  .   .  .
 Rima glottidis......          ...     35
 Rivinus, professor, erroneous opinion of          381  .   .   .
 Rolland, M.       ......          ...     28
 Rousseau, Dr.......          ...    401
 Rush, Dr. James       .....          ...    128
 Ruysch, M.       ......355  ..   .
           preparation of   ...     .          ...     15
           on  the structure of the spleen  .          .... 150
           his opinion on the structure of
              glands.....          .   .   .    419

                                s.

 Sabatier, M. idea of, respecting the bloodvessels
              and the colour of muscles    .     164  .   ■
^.        theory of,  relative to the foetal
^^f         circulation                             ...     75
           observation of, on the stomach   .          ...    105
           supposition of, respecting the  rectum       .   .   .    124
 Sacral artery         .      .       .       .          ...    235
 Saliva         .                                     ...     27
 Salivary glands       .      .       .                 ...     25
 Scapula                                       110  ..   .
         articulation of                         282  .   .   .
 Sciatic nerve                                                 364
       plexus                                       .          !)p,^ 
INDEX.
451
Serum
Scheele, Mr.
Schneider, Dr Conrad
Sheldon, Mr. John
Shippen, Dr. J. G.    .
Sims, Dr.     ....
Skin, vicarious affection of the
Sone, De l.a, opinion of,on the spleen
Soiimmering, interesting discovery of
              idea of, respecting the papillae of
                the tongue
             opinion of, on the villi
            statement of, respecting injections
               of absorbent vessels
Smelling, function of
Spall an zani, Abbe
                   dissertation of
Spheno-Palatine artery
Spleen, general account of
        absorbents of
Spinal marrow
              arteries ofthe
              veins of the
Spermatic arteries
           veins
Splenic artery
Stewart, Dr. J. Bradner
Stiles, Sir F. H E.
Stomach, general view ofthe
         absorbents of
Structure of ganglions
Structure of glands
Subclavian arteries
           veins
Superior mesenteric artery
                   vein
Superior vena cava
Sympathetic nerve
Vol. I.
 Page
387
422

364
339
341
342 
452
INDEX.
VoUl.
 Page
T.
Tears
Teeth
Temporal artery
Thebesius, a German Professor, assertion of
Thigh
Thoracic duct
Thorax
Throat
Thymus gland
Thyroid artery, superior
              inferior
Tongue
Torre,  Father de la
Trachea
Tunica Arachnoidea
Tunica Conjunctiva
Tunica Sclerotica
Tunica Choroides
Tunica Hyaloidea
                fluid in the
Tympanum, cavity of the
           foramina and protuberances of the
u.
Umbilical vessels
Ulna   .
Ulnar artery
      nerve
Urine
Uterine artery
Uterus
Valve of Eustachius
        Vienssens
Valvulae Tricuspides
333 
INDEX.
453
Valvulae Mitrales	Vol. I. Page
Semilunares	
Vas Deferens . „	
Vauquelin, M. ... Vena azygos . . . . . Vena cava, superior inferior	
Vena Galeni ....	331
Vena portarum Venae vesicales .	
Ventricles of the brain Veins, particular distribution of Veins ofthe heart	324
Vertebrae, connexion of, with the head articulation of, with each other Vertebrae-, true Vertebrae, false	276 277 70 84
Vertebral artery	
vein VesaUus, M. his method of examining the brain ....	327
Vesication, causes of Vestibule . . Vidius, professor, reputed discoverer of the pterygoid foramen Vieussens, assertion of	417 389 33
Vitreous humour	365
w.
Wells, Dr.
Wollaston, Mr.
Winslow
Wilson, James Esq.  .
Willis, accessory nerve of
Wrist, articulation of
 75
206

285 
ERRATA.
                             VOLUME  I
Page 74....1ast line, for cervical read vertebral.
     187...1st line, for palati read palate.
     199....6th from below, for their facia read thinfacia.
     223....4th line, for first vertebra of the neck read vertebra ofthe neck.
     265...         for cucnlearis read cucullaris.
  -   277-.17th line, for bones oftlie condyles read bases ofthe condyles.
     335....1st line, for Pons  Variolii read  Pons Varolii.
     344 ...6th line, for orbicidaris muscle,  (see page 171), in the upper eye-
           lid.-) read orbicularis muscle (see page 171.) in the upper eyelids
     352....10th line, for charged read changed.
     357 ...12th line, for plain read plane.
     2,  10, 352, 366, 367, 369, for lumen read lamina—for lamina read
       lamina.
     389....15th line, for solid read hard.
     398....3d line, for these read them.
     409.. .12th line, for as injection read as an injection.
     422...(title) for vicarious connexion read vicarious affections ofthe skin.

                            VOLUME n.
Page 96....11th line, for found read formed.
     156 ...for  Cluipter VI. read Chapter IV.
     272....14th line, from below, for radial read ulnar.
     339.... 17th line, for Portio  Dura read  Portio MoJis 
 
 
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