TREATISE
   SPECIAL    AND    GENERAL




                ANATOMY.



                                  IS*
              BY WILLIAM  E. HORNER, M. D.


PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA—MEMBER OF THE IMPERIAL
            MEDICO-CHIRURGICAt, ACADEMY OF ST. PETERSBURG—OF THE
                    AMERICAN PHILOSOPHICAL SOCIETY, &C.
Multum adhuc restat operis, multumque restabit, nee ulli nato, post mille saccula

  pmcludituroccasio aliquid ailjiciendi.

                                            SENECA, EPIST,
FIFTH EDITION, REVISED AND IMPROVED.
><ss>«
      PHILADELPHIA:


LEA  &  BLANCHARD,

     SUCCESSORS TO CAREY & CO.
1840. 
HSifct
   \$4o
       v.  a
Eastern District of Pennsylvania, to wit: —
  BE IT REMEMBERED, that, on the seventeenth day  of October, in the
fifty-first year of the Independence of the United  States of America, A.  D.
1826—William E. Horner, of the said district, hath deposited in this office the
title of a book, the right whereof he claims as Author, in the words following,
to wit:—
" A Treatise on Special and General Anatomy.  By William E. Horner, M. D.
  Adjunct Professor of Anatomy in the University of Pennsylvania,  Member of
  the American  Philosophical  Society—Surgeon at the Philadelphia Alms
  House, &e.  ' Multum adhuc restat operis, multumque restabit, nee tilli nato,
  post mille saecula prxcluditur occasio aliquid  adjicrendi.1  Seneca,  Epist.   In
  two volumes.  Vol. II.

  In conformity to the Act of the Congress of the United States, entitled, " An
Act for the  Encouragement of Learning,  by  securing  the Copies of Maps,
Charts, and Books, to the Authors  and Proprietors of such Copies, during the
times therein mentioned"—And also to the Act, entitled  " An Act supplemen-
tary to an Act, entitled, ' An Act for the  Encouragement of Learning, by se-
curing the Copies of Maps, Charts, and Books, to the Authors and Proprietors
of such Copies, during the times therein mentioned,' and extending the bene-
fits thereof to the arts of designing, engraving, and etching Historical and other
Prints."
                                       D. CALDWELL,
                           Clerk of the Eastern  District  of Pennsylvania,
GRIGGS & CO., FIUNTEIIF. 
TREATISE    ON  ANATOMY.
BOOK IV.
                        PART II.

                   Organs of Assimilation.

                     CHAPTER I.

              OF THE ABDOMEN GENERALLY.

   The cavity of the abdomen occupies the space between the
 inferior surface of the diaphragm and the outlet  of the pelvis;
 a  considerable part of it is, therefore, within the periphery of
 the lower ribs above, and of the pelvis below.   It is completely
 separated from the cavity of the thorax by the diaphragm, with
 the exception of the foramina in the latter, for transmitting the
 aorta, the ascending cava, and the oesophagus.  It is bounded,
 below, by the iliaci  interni, the  psoas, and the levatores  ani
 muscles;  on the front and sides by the  five pairs of muscles
 called abdominal;  and behind by the lesser muscle of the dia-
 phragm, the Quadrati Lumborum, the lumbar vertebrae, and
 the sacrum.  The figure of this cavity is, therefore, too irregu-
lar to admit of a  very rigid comparison with any of the com-
mon objects of life; but a little reflection, on the course  of its
parietes, will  make it perfectly  understood.   It should be
borne  in  mind, that the very great projection of the  lumbar
vertebras forms for it a partial vertical septum behind; which,
  Vol. II.—2 
6
ORGANS OF DIGESTION.
in thin subjects, is  almost in contact with the linea  alba in
front, and may be easily distinguished through the parietes of
the abdomen, when the intestines are empty.
   The abdominal cavity varies only, inconsiderably, in its ver-
tical diameter, owing to the resistance of the diaphragm above,
and of the pelvis below; neither does it change behind, owing to
the resistance of the spine, the ribs, and the muscles there.   But
as the introduction of food, the development  of gaseous sub-
stances during digestion, the evolution of the foetus, and many
other conditions, require some provision for its undergoing at}
easy augmentation of volume; the latter occurs principally for-
wards and laterally, by the yielding of the  muscles and by the
extension of their aponeuroses.
   The diaphragm and the abdominal muscles, for the most part,
act alternately; as the former descends in inspiration the latter
relax and £,ive way to the  contents of the abdomen; but in ex-
piration, the abdominal muscles contract, and the diaphragm is
pushed upwards by the viscera.  In  attempts at the expulsion
of fseces, and in parturition, these muscles contracting, and the
diaphragm being  fixed all  at the same  moment,  the cavity of
the abdomen is actually much diminished.
   The viscera  contained in the cavity of the  abdomen are of
three kinds.   One kind is engaged in digestion and assimilation;
another in secretion and excretion of urine; and  the third in
generation. As these viscera are numerous, and it is of great im-
portance to determine with precision their position and relative
situation, anatomists are agreed to divide the cavity of the ab-
domen into several  arbitrary  regions.  This is the more advan-
tageous, as the bony  prominences  bounding the abdomen are
not sufficiently  numerous and distinct, to afford those  obvious
points of relation to the viscera which are furnished in other sec-
tions of the body.   To obtain these  regions, consider a line or
plane as extending across the  abdomen, about two inches  below
the umbilicus, from the superior part of the crista of one ilium,
as it appears through the skin, to the corresponding place of the
other side.   Strike on each side a line perpendicular to the pre-
ceding, by commencing at the lower end of the anterior inferior
spinous process of  the ilium,  and carrying it up  to the dia-
phragm.  Extend a fourth line across the abdomen parallel with
the first, and intersecting the last two where they come upon 
OF THE ABDOMEN.
7
the cartilages of the  false ribs.  It is evident that these  four
lines or planes, two horizontal and two vertical, will, with the
assistance of the parietes of the abdomen, furnish nine regions:
three above; three in  the  middle, and three below.  The cen-
tral region,  above, is  the Epigastric; and on  its sides are the
right  and the left Hypochondriac.   The  central  region in the
middle, surrounding the navel, is the Umbilical; and on its sides
are the right and the left Lumbar.   The central region below,
is the Hypogastric; and on its sides are the right and the left
Iliac.  There are also some subordinate divisions: for example,
the hollow in the epigastric region, around  the  ensiform car-
tilage, is called the pit of .the stomach, or Scrobiculus Cordis;
and for an inch  or two around the  symphysis pubis, is the re-
gion of the pubes, (Regio Pubis.)
   Anatomists differ among themselves about the points of de-
parture and the position of the lines, or rather planes,separating
the regions.  Some fix them at definite distances from the um-
bilicus, and  others resort  to the points of the skeleton.  The
umbilicus is the most fallacious mark, because its elevation va-
ries considerably, according to the state of distention of the ab-
domen, it being comparatively higher when the abdomen  is
tumid than when it is  not.  Neither does it answer to take the
anterior ends of the last ribs as the points for the upper horizon-
tal line to prass through; as they, sometimes, are almost as low
down  as the umbilicus itself.  The  superior anterior spinous
processes are also objectionable as  the points  of  departure for
the vertical lines; as  they  leave too much room for the central
regions of the abdomen, and too little for the lateral: I have,
therefore, after some hesitation, thought proper to substitute the
anterior inferior spinous processes; and, especially, as the posi-
tion of the viscera, as  almost universally described, is more  in
accordance  with this  rule.


        General Situation of the Viscera of the Abdomen.

   When the abdomen is  so opened as to leave its viscera  in
their natural position,  they will be found as follows:—

   1.  The Liver, the largest gland of  the body, is in the right 
 8                   ORGANS OF DIGESTION.

 upper part of the abdomen, immediately below the diaphragm.
 It occupies nearly the whole of the right hypochondriac region;
 the upper half of the  epigastric; and the right superior part  of
 the left hypochondriac.   The anterior extremity of the gall-
 bladder projects beyond its anterior margin.

   2.  The spleen is situated  in the posterior part of the left hy-
 pochondriac  region.

   3.  The stomach, in a moderate condition of distention, occu-
 pies the lower half of the epigastric region, and the right infe-
 rior portion of the left hypochondriac.

   4. The Small Intestine, when moderately distended by flatus,
 occupies the umbilical region, the hypogastric, portions of the
 iliac on each side, and also  the upper part  of the  cavity of the
 pelvis, when the viscera of the latter are empty.

   5.  The Large Intestine traverses the cavity of the abdomen
 in such manner  as  to perform  almost the entire circuit of  it.
 It begins in the right  iliac region by receiving the lower extre-
 mity of the small intestine;  it then ascends through  the right
 lumbar and the right  hypochondriac, passes into the lower part
 of the epigastric, or into the upper of the umbilical, according   ,
 to the state of distention of the stomach; thence it gets into the
 left hypochondriac, being fixed higher up there than in the cor-
 responding region of  the other  side; afterwards it goes down
 into the left lumbar and into the left iliac; thence it passes into
 the pelvis, and, descending in front of the  sacrum, terminates
 in the orifice called anus.

  6.  The  Caul, or Omentum, is a membrane, of various densi-
 ties, in different individuals, and lies in  front  of  the intestines.
 Sometimes  it is found spread over the latter like an apron, but
on other occasions is drawn up into the umbilical region, form-
ing a ridge across it.

  7. The Pancreas lies transversely- in the lower back  part of
the epigastric region.  It extends from Ihe  left hypochondriac 
OF THE ABDOMEN.
9
region to the right side of  the spine, and is placed behind the
stomach, so as to be covered by it.

  8. The Kidneys and the Capsulae Renales, two in number
each, are placed in the posterior part of the lumbar region on
the side of the spine.

  9. The Urinary Bladder and the Rectum, in the male, occupy
the cavity  of the pelvis, and in the female between  them are
placed the  uterus, the ovaries, and the vagina.

  As, in the dissection of the abdominal viscera, the subject is
commonly  placed  on its back, so the preceding description is
made out with  a strict reference to that position.   Some modi-
fication in  the shape of the abdomen, as well as in the situation
of its contents, occurs in standing upright.  The front of the ab-
domen becomes more protuberant, the lumbar vertebras make
a greater  projection forwards.   The pelvis is so adjusted, in
order to bring the acetabula  directly in  the line of support to
the spine, that the convexity  of the sacrum presents almost up-
wards, and the superior  straight looks  forwards  and upwards
towards the navel, so that much of the weight of the viscera is
thrown upon the pubes.   In  this attitude most of the viscera
descend, but more obviously the liver, from its weight, size, and
solidity. Portal has verified this  descent by comparing the
thrusts of poniards into the liver in the erect, with those inflict-
ed  in the  horizontal position.  He also  asserts that the same
may be ascertained  in the  living body by applying the fingers
under the  false ribs, and then directing the person to change
from  the recumbent into the vertical position.  The spleen af-
fords  the same results when it is  slightly enlarged, and the de-
scent of the liver and spleen  will of course ensure that of the
stomach and intestines.  According to Winslow, the  pain and
faintness which are felt after a long abstinence, come  from the
vacuity of  the stomach and intestines, which thereby withdraw
their  support from the liver, and  permit it  to  drag upon the
diaphragm.
  The presence of flatus in  the stomach and  intestinal canal,
seems to be entirely natural  to  them;  for it  is comparatively
rare to. find them  destitute  of it, even  when they contain no 
10                  ORGANS OF DIGESTION.
food or fasces.  The large intestine is, however, more frequent-
ly found  contracted  or empty than  the small.  Owing to  the
flexible character of a considerable portion of the abdominal pa-
rietes, the latter, by their own contraction, as well as by atmo-
spheric pressure, are kept in close contact with the viscera; and
the viscera again, by the same influence, are kept in close con-
tact with one another; so that, notwithstanding the irregularity
of their forms and the fluctuating size of the hollow ones, there
is no unoccupied space in the cavity of the belly.
   Several instances are reported by anatomists, in which a to-
tal transposition of the abdominal  viscera,  has occurred, so that
those which belonged to the right side were placed in the left.*
They are, however, exceedingly rare.  In the entire observation
of my life, amounting to twenty-seven years of anatomical  stu-
dy, and extending itself to many hundred bodies,  I have never
met with one instance of it.
                    CHAPTER II.

OF THE PERITONEUM, AND SEROUS MEMBRANES, GENERALLY.

                SECT. I.—OF THE PERITONEUM.

  The sides of the abdomen  are lined, and its viscera are co-
vered by a membrane called Peritoneum.  As the reflections of
this membrane, by being  thrown over  the periphery of almost
every viscus  of the  abdomen, consequently, assume the same
shape; and as it lines, without exception, the interior surface of
every part of the abdomen, its form is extremely complicated,
and  can only be judged  of accurately after the  study  of the
viscera is completed.  For the  present it will only be  necessa-
ry to give the outline of it, leaving the details to each appropriate
occasion.
* Portal, Halter, Sandifort, &c. 
OF THE PERITONEUM.                   11
  In man, it is a complete sac, having no hole in it;  but in wo-
man, its  cavity communicates externally through the Fallopian
tubes.  It has a double  use:  In consequence of covering  the
viscera, it is so reflected  from them to the sides of the abdomen,
that its processes keep the viscera  in their proper places, and,
therefore, answer as ligaments: again, its internal surface  being
smooth, indeed, highly polished, and continually lubricated by a
thin, albuminous fluid, corresponding with the  synovial  mem-
brane  of the joints, the  motions which the viscera  have upon
each other in exercise, and in the peristaltic action of the bow-
els, are much facilitated.
   The manner in which a double  night-cap is  applied to  the
head,  will afford the easiest conception of the reflections of the
peritoneum.  If there were only one viscus in the belly, and that
of a somewhat regular  outline,  as the spleen,  the comparison
would be rigid, and perfectly appreciable.  One part of the cap
is close to the head, and compares with the peritoneal  coat of
the spleen; the other is loose, and is equivalent to the peritoneum,
where it is in contact with the parietes of the belly.  It is also
evident from this, that none  of the viscera can  be  said  to be
within the cavity of the  peritoneum; that they are all on its out-
side; and that a viscus,  in getting a coat from the peritoneum,
merely makes a protrusion into  its cavity.  Starting with this
simple proposition, it is easy to conceive of a second, a third body,
and so on, deriving an external coat  from a protrusion  into the
 same  sac.   Admitting these bodies to be spheres, the proposition
 is immediately intelligible; and, as a last step from it, the idea is
 not rendered much more complex by substituting any bodies even
 the most irregular  in form, for these spheres.
   Such, then, is the fact in regard to the stomach, intestines,
 &c;  they all, with the  exceptions to be stated, derive an ex-
 ternal coat from the peritoneum.
   The Peritoneum is, for the most part, smoothly spread upon
 the interior surface of  the abdominal muscles.  It adheres to
 them with considerable firmness by means of intervening cellular
 substance: this adhesion, where it closes the posterior opening of
 the umbilicus, is unusually strong.  Below, the uniformity of the
 membrane as it descends from the navel  to the pelvis  is inter-
 rupted by its being reflected over the urachus, and over the re-
 mains of the umbilical artery on each side.   Where the urachus 
12                  ORGANS OF DIGESTION.
is, it forms an oblong prominent ridge, reaching to the upper ex-
tremity of the bladder;  and, as regards each umbilical artery,
the duplicature is of a variable breadth in different individuals;
but always  forms a well marked falciform process, reaching
from near the umbilicus to the lower side of the bladder, and di-
viding the inguinal region into two parts or fossse, one next to
the pubes, and the other near to the  ilium.   In  the undistended
state of the bladder the  peritoneum reaches to the pubes, is re-
flected from the latter to the upper, and then goes over the pos-
terior surface  of  the bladder.  In the male, it  goes from the
posterior lower end of the bladder to the rectum, but, in the fe-
male it does not descend so low there, and passes from the blad-
der to the vagina and uterus, and  afterwards to the rectum.
  In the concavity of the ilium, and in the lumbar region, the
peritoneum is attached by long loose cellular substance, which
permits it  to be stripped off easily, simply by tearing.   In these
several regions it encounters the colon, over  which it is reflected,
and thereby forms the Mesocolon; thence it passes in front of
the kidneys, but separated from them by a thick  layer of cellu-
lar and  adipose matter, and immediately afterward it is thrown
into a long duplicature, extending obliquely across the lumbar
vertebrae from above, downwards, and  to the right side.   This
duplicature includes the small intestine, and is  the  Mesentery.
  In the highest regions of the abdomen, the peritoneum is in the
greater  part of its extent uniformly reflected over  the concave
surface of the diaphragm, and adheres so closely to it, as to re-
quire a cautious and protracted dissection for its entire removal.
As the remains of the umbilical vein of the  foetus are still found,
but in a ligamentous condition, going from  the navel to the un-
der surface of the liver, their existence  gives rise  to  the falci-
form ligament, a broad duplicature of peritoneum, which passes
from the upper half of the linea alba and from the middle line
of the diaphragm to the liver.   Another line of altachment, or
of reflection, of this  membrane to the liver, is found  all alon<*
the posterior margin of the latter.   In the same region, it is also
reflected from  the diaphragm to the spleen  and to the stomach.
Such is the general  account  of the course  of  the  peritoneum.
Each of the duplications has a distinct name, and some  peculi-
arity of organization or of relation, which will require a specific
description and a  frequent allusion to it. 
OF THE OMENTA.                     13
  It is proved, from what has been said, that the peritoneum is
a single and complete sac, and that, with the exception stated of
the Fallopian tubes, there is no  hole in it either for the passing
of blood vessels, nerves, or viscera.   And that it is so folded over
the abdominal viscera, that with patience  and sufficient address,
one might remove it from their surface and extract them, with-
out even laying open its  cavity: an experiment said to have
been successfully accomplished  by Nicholas Massa,* and some
other anatomists.

                  SECT. II. — OF THE OMENTA.

   There are four processes of the peritoneum,  each  of which is
designated under the term Omentum,  Epiploon, or Caul.

   1. The  Omentum  Minus or  Hepatico-Gastricum, extends,
as its name imports, between the liver and the  stomach.   It be-
gins at the transverse fissure of the liver, and  proceeds from it,
from  the right side of the lobulus spigelii, the  front  of which it
conceals, and from the inferior posterior face of the tendinous
centre of the diaphragm; it is attached to the lesser curvature of
the stomach in all the space between the cardiac and the pylo-
ric orifice.  Its right margin reaches from  beyond  the pylorus
to the duodenum, and  includes the  vessels going to the liver,
and the biliary ducts; in consequence of which, this margin is
called the Capsule of Glisson.  The capsule is, however, more
properly the condensed cellular substance within.
   The two lamina? which compose  the omentum  minus  are
thin and transparent,and have but little fat in them; in approach-
inc the stomach they become very distinct from each other, and
receive between them the superior coronary vessels of the sto-
mach.  One lamina then goes before the stomach and the other
behind, in  the form of a  peritoneal covering.  These laminae,
having covered in that way the anterior and the posterior surface
of the stomach, unite again on the greater curvature of the lat-
ter, to form the beginning of the omentum  majus.

   2. The Omentum Majus or Gastro-Colicum, as indicated by its

              * Anal. Liber. Introduct. an. 1539. Portal.
   Vol. II.—3 
14
ORGANS OF DIGESTION.
   name, is connected at one end all along the greater curvature of
   the stomach, and by the other along the transverse part of the
   colon.  As  it commences by two  lamina?, so it is continued
   throughout in the same way.   It is commonly found more or less
   spread on the front surface of the small intestines, but occasion-
   ally it is tucked up in the epigastric region.  When fairly spread
   out, either naturally or artificially, its course will be found as fol-
   lows: It first of all descends from the stomach to the pelvis; it
   then turns upwards, so as to reverse its course, and continues to
   ascend till it reaches the colon.  Its two laminae then separate
   and receive the colon between them, so that, in this  respect, the
<   arrangement is entirely conformable to what happens to the sto-
   mach.  The subsequent continuation  of these laminae is the
   mesocolon, which will be more particularly described.
    As the  omentum majus  consists of  two laminae in its whole
   extent, it is clear that it resembles a flattened bag lined by another
   bag;  so that in its  whole thickness, when held between the fin-
   gers,  there are four  laminas.   It is an irregular  quadrilateral
   membrane, which,  in corpulent subjects, is  interspersed with a
  great deal of fat; but in such as are emaciated, it is wholly des-
  titute of the  latter; and instead of being entire in its parietes is a
  delicate reticulated membrane, so that the rule about the integ-
  rity of the peritoneum  is  not fully accurate as applied to this
  section of it.  On the right side it is  continous with the omen-
  tum colicum, and on the left  with the  omentum gastro-spleni-
  cum.

    3.  The Omentum Colicum may be  considered as a continua-
  tion of the omentum majus along the ascending and a part of
  the transverse colon.   In some rare cases, (for in my own ob-
  servations I have not met with the arrangement,) it's origin is
  continued  downwards to the ccecum, and at its left margin is
  extended along  the transverse colon to the spleen.   Much rnore
  commonly it is, as stated,  simply an  appendage  of the great
  omentum, or its right flank, advancing for a short distance along
  the ascending colon.
    It consists of but two laminae in all, commonly containing fat,
  but  in this respect subject to  the same rule as the omentum
  majus. 
OF THE OMENTA.
15
   4. The Omentum Gastro Splenicum is the* loft flank or mar-
 gin of the omentum  majus, extended from the great end of the
 stomach to the spleen.  It of course consists of but two laminae,
 which contain  between them the  splenic vessels and the vasa
 brevia.

   By looking for the posterior end of the gall-bladder, and then
 passing a finger under the right margin of the hepatico-gastric
 omentum, or in other words, under the capsule of Glisson, where
 it extends from  the liver to the  duodenum,  the finger will be
 found to have insinuated itself behind  the stomach, and, by  be-
 ing directed  downwards, will be thrust into the sac or cavity of
 the great omentum.   In children, where the latter is less reticu-
 lated than in  adults, and consequently more entire, a large blow-
 pipe introduced at the same point will enable one to inflate this
 cavity, and to separate its anterior from its posterior wall. This
 aperture, called  the foramen of Winslow, is the route by which
 the internal or lining lamina of the omentum majus is introduced,
 so as to make this process of peritoneum double throughout  its
 whole  parietes.  Though this fact of duplicity is generally con-
 ceded, no author heretofore, to my knowledge, has pointed out
 satisfactorily the means; and for the suggestion of it, I am  in-
 debted to a learned and zealous member of  the profession, now
 Professor Hodge of the University.  Struck, at an early period
 of his studies, with the difficulty  of tracing a double sac to the
 omentum majus, out of a single  membrane of the peritoneum,
 this suggestion was happily made by him to remove the difficul-
 ties of other explanations.  An  attempt at  a  diagram formed
 upon any other principle I have invariably seen to fail.  If the
 reader has conceived the idea, the inference will be plain, that
 the lining lamina of the omentum majus is continued as a com-
 mon peritoneal covering over the posterior face of the stomach,
and then forms the posterior lamina of the hepatico-gastric omen-
tum.  It  will also be plain that the same lamina, having reached
the colon in  its return, continues afterwards as the upper lamina
of the transverse mesocolon.
  From what has  been said concerning the general qualities of
the peritoneum, it is to be understood that though it enjoys much
power  of gradual extension, nevertheless this quality  is not suf-
ficient  to enable it to endure, without  a special provision, the 
16                  ORGANS OF DIGESTION.

sudden and extensive dilatations to which the stomach and bow-
els are exposed, from the introduction of food and from the evo-
lution of gases during digestion.  Of all the coats of these organs,
it is the least extensible and contractile; its rupture, therefore, is
guarded against  by one invariable rule.  For example: as the
muscular and other coats of the stomach dilate, the peritoneum
is drawn from the omentum minus and majus to cover the sto-
mach; therefore, as the stomach enlarges, the omenta diminish:
and as the  stomach decreases, the omenta, by the restoration
of peritoneum, resume  their primitive  size.   In this way the
uterus, notwithstanding  its great  augmentation in  the progress
of pregnancy, still keeps itself covered by peritoneum, from the
ability of the latter, as mentioned, to slide from one part and to
apply itself to another.  The true intention, then, of the appa-
rently useless length of many processes of the peritoneum, is
explained, by their being a provision for the augmentation of
the hollow viscera of the abdomen, in the discharge of their na-
tural functions.  Adopting this explanation as the  basis of our
observations, we  shall find that according  to the  probable or
even possible augmentation of a viscus, so are its peritoneal at-
tachments.   The stomach, which next  to  the uterus  enlarges
more than any other viscus, gets its subsidiary supply of perito-
neum from the length of  the omentum minus and majus; the
colon, which is next in order, is supplied from the  length of its
mesocolon ; the small intestines, which are next, from the length
of the mesentery.   The latter, however, would be too long for
that simple purpose; but the objection is removed by recollect-
ing that the mesentery  has also to  accommodate numerous
chains of lacteal glands, through which  the chyle must pass in
its elaboration, before it is fit to enter into the general  circula-
tion.  The liver,  being of  a size almost stationary, has  its peri-
toneal attachments proportionally short; and its peritoneal co-
vering, from the shortness of the connecting cellular substance,
is disqualified from sliding.  The  spleen is in the same predica-
ment with the liver, except that its size is not stationary;  but,
in this case, the peritoneum presents a phenomenon entirely re-
markable: it wrinkles  upon the contraction  of the spleen.
   If this mode of reasoning, derived, from  an arrangement of
parts which no one denies, be correct, it follows that physiolo-
gists have erred sadly in the supposed uses of the omentum ma- 
OF THE OMENTA.
17
jus.   That  this organ is, in fact, only subsidiary to the enlarge-
ment of the stomach and colon, so as to prevent the rupture of
their peritoneal coat, and that it is neither intended to keep the
belly warm, as  so learned a naturalist as M. G. Cuvier has sug-
gested,* nor is it a special store-house for the wants of the sys-
tem  during the destitution of other aliment, farther than adipose
matter in other parts of the body is.f   In regard to the first theo-
ry, it does not appear  that the inhabitants of cold  climates are
better furnished with an omentum majus than those of the torrid
zone: that it is  better developed in winter than it is in summer;
that  it is tucked  up in warm weather  to  cool the intestines, or
spread out in cold weather to make them more comfortable.   On
the contrary, it is ascertained that its position is variable at all
seasons; that in the coldest of weather it  is as often found col-
lected in the epigastric region, or to one side of the abdomen, as
it is  in the warmest;  consequently, its  position is the result of
whatever motions may, for the time, have been impressed upon
it by the distention of the stomach, and  by the peristaltic move-
ments of the bowels.   In regard to the theory of Dr. Rush, the
objection is insurmountable, that children, who are equally, if not
more exposed  to starvation and  sickness than adults, never have
fat, except  in  very small  quantities,  in  the  omentum, and  that
only along the course of its vessels.   The fat is, therefore, not to
be viewed as an essential circumstance in the structure of the
omentum, as all  children and many adults have  it only very
sparingly; for  the  omentum being wanted  as a membrane of
reserve to the  stomach and  colon,  the deposite of fat in it, is in
obedience to one of the general laws  of the system, whereby the
cellular substance beneath the serous membranes is disposed to
secrete fat as the individual advances in life; which is exempli-
fied on the heart and in the  pleura.  Another argument is,  that
in  the ruminating animals, where there are  four stomachs, and
from the vegetable nature of their  aliment these stomachs must,
in  the course  of  digestion, be very much distended, the great
omentum is of proportionate magnitude.^
  As occurs in  other parts of the body, also, the fat of the  omen-

 * XXII. Legon D'Anat. Comp.
 + An Inquiry into the Uses of the Omentum, by James Rush, Philad. 1809,'
 i Cuvier, XXII. Le^on, loc. cit
                             3* 
18                  ORGANS OF DIGESTION.
turn accumulates in animals that take but little exercise, while it
is very deficient in such as lead an active life.
  I am induced to believe that the hard knots felt in the abdo-
men of such persons as suffer from abdominal  affections, fre-
quently depend upon the accumulations of the omentum  majus
at particular but variable points.

    SECT. III.--GENERAL ANATOMY OF THE SEROUS MEMBRANES.

  As the peritoneum presents one of the best examples of a nu-
merous class of membranes, called Serous, it will be useful at
this point to inquire into their  general condition and properties.
They are, for  the  most  part,  thin, and strongly resemble com-
pressed cellular membrane; having been, indeed, by some ana-
tomists, considered as such.   They invariably assume the form
of perfect sacs, and as they are found in all parts of the  body,
they are iiept  distinct from each other.  The arachnoid  mem-
brane  of the  brain,  the pericardium, the pleura, the synovial
membranes of the joints, the bursas mucosas of tendons, the peri-
toneum, and the  tunica  vaginalis  testis, belong  to this  class.
They are not all of the same thickness, as some are much more
dense than others; they adhere to neighbouring parts by a la-
mina of cellular substance, which is also of variable thickness
and ductility;  indeed, on some occasions, it is not entirely dis-
tinct, from its  extreme shortness and tenuity.
  As the serous membranes are only displayed over the surface
of the organs which they cover, after  the manner of a double
night-cap drawn over the head; their cavity always remains en-
tire, notwithstanding it is variously modified  by the shape of the
organs protruded into it; and has its parietes in contact,  owing
to external  compression.  They are entirely distinct from the
essential structure of the organs covered, and are displayed over
those of the most dissimilar functions, as, for example, the intes-
tines and the liver.   A sac of this description, then, is of infinite
importance in  establishing between  organs which  border upon
one another a strong partition: and, consequently, in warding off
any  injurious  influence  which their dissimilar  natures  would
otherwise cause them to have  upon each other.  Important or-
gans are, therefore, invariably  thus insulated, so that whether in
a healthy or in a diseased state, their actions are carried on 
ANATOMY OF SEROUS MEMBRANES.
19
within themselves; and not only so, but it is even possible, and,
indeed, is found in morbid dissections, every day, that an organ
may be diseased while  its serous covering is unaffected; or the
reverse.  Thus, we have large suppurations in the liver, while its
peritoneal coat is healthy; large accumulations of  water in the
tunica vaginalis  testis, while  the testicle itself is sound;  in the
thorax, with sound lungs and heart; in the abdomen, with vis-
cera generally sound;  in the joints, without an affection  of the
bones.  Nothing is more common than to see partial adhesions,
the result of inflammation, causing the opposite sides  of these
sacs to adhere, without any  evident constitutional or visceral
derangement; and some of our plans of cure, as in the hydro-
cele, are founded upon this well established fact.
   The serous membranes  are throughout  thin,  transparent,
and white: in some points their tenuity is so extreme that they
seem  to  consist  simply in  a  smooth, polished  surface, spread
over parts; this  is strikingly the case on the interior face of the
dura mater, on the ventricles of the brain, and on the cartilages
of the joints.  The evidence of their extension there, is  conse-
quently derived  principally from induction;  and from morbid
alteration, in  which  they become  thickened.  Their  internal
surface in  a natural  stale, is always  smooth,  highly polished,
shining;  and, being also lubricated  by  its peculiar  unctuous se-
cretion, the opposite  parietes, when  they come into  contact,
glide freely upon  each other;  a  circumstance indispensable to
the free action of the joints, and to the  peristaltic motion  of the
bowels.  Bordeu has  asserted, that these remarkable characters
of the serous membranes depend upon  the compression and the
friction to which they are continually exposed: but to this opi-
nion the  argument of Bichat  is unanswerable, that in their ear-
liest observable period in the fostus  they have the same polish.
   The fluid secreted  from  the  serous membranes resembles,
strongly, the serosity of the blood.   It is poured out continually
by the exhalent orifices, and in a short  time afterwards is taken
up by  the absorbents; so that in a natural state there is seldom
more than sufficient to  lubricate the surface of the membrane.
When the abdomen of an animal recently killed is exposed to the
air, this fluid rises in the form of a vapour.  The several experi-
ments, as the application of heat, mineral acids, and so on, which
prove the abundance of albumen in  the  serum  of the blood, pro- 
20
ORGANS OF DIGESTION.
 duce the same results when applied to the secretion from the se-
 rous membranes.
   The system of serous membranes has been considered by Bi-
 chat, and others, as only a modification of cellular membrane, for
 the^following reasons.   The inflation of air into the cellular tis-
 sue subjacent to them, reduces them to the form of cellular sub-
 stance.   Protracted maceration produces the same effects with
 more certainty and precision.  When cellular membrane is in-
 flated, the parietes of  the.  distended cells resemble strongly the
 finest  parts  of the serous  system, as the arachnoid membrane.
 There is an  identity of functions and of affections, for they are
 both continually  engaged in the great work of exhalation and ab-
 sorption, and suffer in the same way from dropsical effusion, with
 the only difference that the latter  is more amassed  in  the one
 than in the other.   My own experience goes to prove, that drop-
 sy very seldom manifests itself, to  any extent, in the cellular tis-
 sue without also  going to  the serous cavities, and the reverse.
 The serous membranes are also of a uniform texture, like cellular
 substance, and present no appearance of a fibrous  matter.
   The serous membranes are furnished with a great abundance
 of exhalent pores, and  of absorbents, which carry on their func-
 tions with great activity.  They, when healthy, receive only the
 colourless part of the blood, whence the uniform transparency of
 these membranes.  The existence of exhalent pores, is proved
 by strangulating a piece of intestine with a ligature for thirty-six
 or forty-eight hours, when they become evident, by dilating them-
 selves so as to receive red blood.   A fine coloured  injection pro-
 duces the same result; and also moistens, by the escape of its wa-
 tery particles, the surface of the intestine, by a very fine halitus
 or dew.  The intestine of a living animal, if wiped perfectly  dry,
 will, after the same way, soon present another coat of serosity on
 its surface.  The existence of absorbents to a  great extent in
 them, may also be equally well proved, as they very readily re-
 ceive a mercurial injection, which diffuses itself over their whole
 surface, and causes them to have the appearance of being formed
entirely of such vessels.   The readiness with which fluid effused
into their cavities is taken up, is another proof of the same.  Bi-
chat once saw them distended with air in a man  who had be-
come emphysematous from poisoning.  Mascagni has frequently
found them distended with the fluid of dropsical collections, which 
ANATOMY OF SEROUS MEMBRANES.
21
he recognised by its colour.   It happened 1o the same anatomist
to find in two bodies, where there had been an effusion of blood
into the thorax, the absorbents of the lungs gorged with blood.
This faculty of absorption may sometimes be proved to continue
for some hours after death, by keeping an animal in  a warm
bath.   Mascagni asserts, that he has witnessed its continuance
for fifteen, thirty," and even for  forty-eight hours;  it is not im-
probable, however, that  there was some  illusion in these  in-
stances.
   It  is more than probable  that the  serous membranes  are en-
tirely deprived of red blood vessels; the latter unquestionably ex-
ist, in great numbers, on the exterior surface, where they creep
through the cellular  substance, but they may  be removed with
a scalpel without affecting the continuity of these membranes.
Again, where these membranes are free and unconnected on both
surfaces, as in some parts of the tunica arachnoidea, there is no
appearance of red  blood vessels.  In hernial protrusions, where
there is a considerable prolapse of peritoneum, the blood vessels
which are found abundantly about the neck of the sac do not fol-
low the course of  the  protrusion.  Unquestionably some com-
munication exists between  the  arterial system and the serous
membranes, as proved by exhalation  and morbid phenomena,
but the mode is not well ascertained.
   In common hernia and in dropsy, the serous membranes be-
come more thick:  from my dissections I  am inclined to think,
that  this change is not so great as is generally  allowed; for most
frequently, by a careful  removal of the  exterior  cellular sub-
stance, they have been restored to their primitive condition.  In
other cases, as in large umbilical  hernias, they are so much  at-
tenuated as to be found with difficulty.
   The power  of extension  which these membranes  possess,  is
strikingly marked in dropsical effusions, in the development of
tumours, and in pregnancy; but much of this apparent quality
is derived  from their mode of attachment to adjacent parts,
whereby they are drawn fror? one surface  to cover  another.
This happens  daily where  the  peritoneum is drawn from the
lower part of the abdomen to cover the bladder in the distentions
of the latter; in pregnancy, where it is drawn upon the growing
uterus from all the neighbouring parts; and in the distentions of
the stomach by food or  flatus,  where it is drawn up from the 
22
ORGANS OF DIGESTION.
omenta.  The serous membranes have also a power of contrac-
tion equal to that of their extension;  but it should not be con-
founded with that  condition where they are simply restored by
the connectinor cellular substance, to the surfaces to  which they
originally belonged.
  The sensibility of the serous  membranes, from the want of
nerves in them, is extremely obscure in a natural state, and only
affords an imperfect sensation of touch.   This is proved by the
impunity with which they may be  irritated on living animals.
But, when the condition of inflammation is once established, they
feel the most acute and distressing pain.   Though, they resist
most frequently, and for a long time, disease in adjacent parts,
yet it not unfrequently is extended to  them  at last.   In such
cases, it is generally a local instead of a universal affection, which
is communicated to them:  Thus, in the catacer and scirrhus of
the uterus; in disease of the spleen, and so on; the portion of pe-
ritoneum nearest the affected organ manifests the marks of  the
disease by preternatural adhesions and by disorganization, with-
out the whole membrane being involved.
  As the serous system consists in many species of sacs, so each
of them has some peculiarity of organization, of attachment, and
of vital properties, which is stated elsewhere in the account of
the species themselves.
                    CHAPTER  III.


              OF THE CHYLOPOETIC VISCERA.

                 SECT. I.--OF THE STOMACH.

  The Stomach  (Ventriculus, Siomachus)  is a  hollow viscus
situated in the epigastric region, intended to receive at one end
alimentary matters from the oesophagus, and to  transmit them,
at its other extremity, after digestion, into the  intestinal  tube,
where the nutritious part of the food  is absorbed into the circu- 
THE STOMACH                      23
lation.  It is a conoidal sac, curved considerable upwards, and
presents two Faces, two Orifices, two Curvatures, and two Ex-
tremities.
  The Faces  of the  stomach are, from their position, named
anterior and posterior, or, one presents to the linea  alba and
the other towards the spine.   The flat configuration is rendered
more obvious when the organ is empty; for "when distended it
is rounded, and the anterior face is caused to look forwards and
upwards from the resistance of the spine behind, while the pos-
terior is of course in  an opposite direction.  In other respects
they do notjpresent any thing worthy of particular attention.*
   The two Orifices of the stomach are named Cardia and Py-
lorus.  The first  is at the left and most  superior part, but re-
moved to  the distance of  two inches or more from the left  ex-
tremity.   It is generally considered  a smooth uninterrupted
continuation of  the oesophagus into, the stomach, immediately
after the  oesophagus has passed  through the diaphragm into
the abdomen.  But in a preparation,! of  this  organ,  made by
drying, and now in the anatomical cabinet, a circular rounded
pad is very perceptible at the cardiac orifice; being elevated
two lines or more all  round, so that it makes  a perfect ring of
from eight to  twelve lines broad at its base.  This pad seems
to be composed  of a  cellular substance, which  is almost per-
fectly white, elastic, and consists of the finest filaments, resem-
bling carded cotton:  it is  placed between  the lining membrane
of  the cardiac orifice and the adjoining  coat.   The pylorus,
when viewed externally, looks like  a smooth continuation of
the stomach into the duodenum; but when felt, there is a mani-
fect thickening of the part, depending upon a structure to  be
presently explained.   It points upwards  and to  the  left side,
but is, by  the whole thickness of the liver,  lower down than the
cardia.
   The two Curvatures are  designated the great and small, or
the upper  and the lower.  The first, forming the  upper  margin
of  the stomach,  is bounded  at its extremities by the orifices,
and is very concave; its curvature is maintained both by a na-

  * In some cases the  posterior face of the stomach  is concave to accommodate
it to the spine: this is best seen on inflation and drying.
  f Made* December, 1828. 
24
ORGANS OF DIGESTION.
tural configuration and by the small omentum.   The great cur-
vature forms the whole inferior periphery of the organ, extend-
ing also from one orifice to the  other.  When the stomach is
flattened, these curvatures form very evident boundaries to the
anterior and the posterior faces.
  The Extremities of this  organ are singularly different  in
size.  That on the left forms the base of the cone, or  the
large extremity, and projects considerably  beyond the cardia
towards the spleen.  It is a rounded  cul-de-sac, or tuberosity,
the dimensions of which will, of course, vary according to  the
state of distention.  The right extremity, on  the contrary, is
produced by a gradual diminution of the organ from its middle
to the duodenum.   When  the stomach has  approached within
an inch or  two of the  latter, it  suffers a sort of constriction,
which gives to the right end a more cylindrical shape.  This
part is  sometimes  called  the  little cul-de-sac, or the antrum
pylori.
  Where the stomach has been kept empty for some time pre-
viously to death, it is found not much larger than an  intestine;
its variable magnitude, therefore, prevents  any very rigid rule
of dimension from being applied  to it; most commonly,  how-
ever, we find it between the capaciousness of a pint and a quart
measure.
  It is retained in its situation  by its continuity with the oeso-
phagus and duodenum; also by  the hepatico-gastric, and  the
gastro-splenic omentum.   It is in  contact  above, at  its lesser
curvature, with the diaphragm, the left lobe of the  liver, and
the lobulus  spigelii; at its great extremity with the spleen, at
its posterior face with the pancreas, and at its greater curvature
with the colon and the  mesocolon.

  The stomach is formed by four Coats or laminae, of a charac-
ter  essentially differing from each other: The  Peritoneal, the
Muscular, the Nervous, and the Mucous.
  The Peritoneal  Coat envelops the stomach completely, and
adheres closely, except at the  curvatures, where, as has been
mentioned,  a provision is made for the distention of the organ,
by the looseness and the separability of the attachment of the
two laminae of  the omentum minus  and majus.  An uncovered
space will,  consequently, be found between the  laminae at these 
THE STOMACH.                     25
places, along which  the vessels run  that  furnish the stomach.
The peritoneal coat is very thin, and is attached to the subjacent
muscular, by very fine cellular substance, which permits it to
be raised from the muscular by a careful dissection.
  The Muscular Coat is intermediate in thickness to that of the
intestines and of the oesophagus, but its fibres are pale, are col-
lected into flattened  fasciculi, and go in three directions.  The
most superficial are a continuation of the longitudinal fibres of
the oesophagus,  and are less numerous and less  uniform in their
distribution than the circular fibres.  The greater part of them
forms a flattened broad fasciculus, which extends along the lesser
curvature of the stomach, from the  cardiac  to  the pyloric ori-
fice.  A thinner and less distinct fasciculus may be traced over
the great cul-de-sac, and somewhat indistinctly, along the great-
er curvature; and a few others may be seen on the anterior and
posterior faces of the stomach.  The second series consists in a
lamina of circular fibres distinctly covering the whole surface
of the organ.  They are not so numerous near the cardia, but
become more abundant as they are examined towards the pylo-
rus, in the  vicinity of which  they are  multiplied so as to form
a lamina of two lines or more in thickness.  The circular fibres
are  parallel with  each  other, and,  when  the stomach is much
distended,  their  fasciculi separate so as to leave interstices be-
tween them in many places.  The individual fibres do not sur-
round entirely the stomach, but are rather segments of circles.
The  third  and  deepest  series of  fibres may be called oblique,
and are arranged into two broad flattened fasciculi, one of which
is placed to the  left side of the  cardia, and is  prolonged over
the anterior and the posterior faces of the stomach; while the
other, being  to the right of the same orifice, is extended over
the anterior and the posterior faces of the cul-de-sac, where it
supplies the  want of transverse  or  circular fibres:  this series
may be considered as a continuation of  the circular fibres of
the oesophagus.
   The Nervous or Cellular Coat connects  the muscular with the
mucous.   It is formed by  a  compact,  thick, and short cellular
substance, which contributes much  to the general  strength of
the  oro-an, and serves  to  conduct  the blood  vessels and the
nerves to the mucous coat.
   The  Mucous  or Villous Coat is the most internal, is not quite
      Vol. II.—4 
 26                  ORGANS OF DIGESTION.

 a line in thickness, and can be readily raised up by dissection.
 In an  undistended state  of the stomach it is arranged  into a
 number of wrinkles, which  are very  irregular in their form,
 size, and direction, but disappear  immediately on distention, or
 at least leave  but very faint traces.  It is continuous with the
 internal membrane of the oesophagus and of the duodenum, but
 presents a surface differing from either of them, and which  is
 rendered very apparent by floating it in water.  The epidermis,
 which is continued along the internal  face of  the oesophagus,
 ceases  as mentioned around the cardiac orifice, and, by a slight
 maceration, may be raised up and demonstrated  to terminate
 there.
  This mucous membrane or coat, the office  of which is to se-
 crete the gastric juice for the digestion of articles of food, pre-
 sents a surface that resembles very much common velvet, from
 whence the term villous was applied to it.   Jf it be  perfectly
 healthy, and the  individual died suddenly a few hours after eat-
 ing—it is found of a uniform  light pink colour, without blotches
 or any thing of extravasation under it.  This fact I have had
 several opportunities of verifying, by experiment and by autop-
sies:*  And more lately in the person of a criminal, Williams,
executed for murder.t  It is usual, in fact, to find it, if examined
 a short time after death, having, particularly  along the smaller
 curvature and at the great end, a  pink and sometimes a deeper
 colour, produced by an accumulation of blood in its veins.
  The  texture of this  membrane is soft, loose, and easily lace-
rated.   When floated in water and  examined with a magnify-
 ing glass, it is  found to have a superficial honey-comb arrange-
 ment, and to be studded with a multitude of small follicles  or
orifices.  In the  vicinity of the  cardiac and of the pyloric ori-
 fice,  the same arrangement is  more obvious, and conducts to
 some small muciparous glands, which are more or less apparent,
 and called the glands of Brunner.
  At the junction of the lesser extremity of  the stomach wiih
 the duodenum, the internal membrane is  thrown into a circular
 duplicature constituting the  pyloric valve, and abridging the
 size of the orifice.   It is seen most favourably  in the distended

  * See Amer. Journal Med. Sciences, Vol. I. 1827. Horner's Pathol. Anat
 p. 195, &c.
  t Aug. .9 1839. 
THE STOMACH.
27
and dried state, and then presents a sort of septum not unlike
the form of the  iris.   Around  the external periphery of this
ring, the circular  muscular fibres have a  sudden augmentation
of number, which gives them, when viewed from the duodenum,
the appearance of a distinct circular muscle, occasionally called
the muscle of the pylorus, but it does not exist in a state so se-
parate as this name indicates.   The opening of the valve is ge-
nerally circular, but sometimes ovoidal, and it is sometimes to
one side.'

   It is very common to find the stomach divided as it were into
two compartments, by a contraction of its middle,  resembling
that of an hour  glass.   It  is said that this occurs  habitually
during digestion; in my personal observations, however, I have
seen the stomach  more frequently in this state when it contained
nothing, not even air, than when articles of aliment were in it.

   The  stomach  is  extremely  vascular.   Its arteries,  being
branches of the Coeliac, are the Gastric, the Right, and the Left
Gastro-Epiploic, and the Vasa Brevia. The first goes along its
lesser curvature, the second and the third  along its greater cur-
vature, and the last, from four to six in number, go to its  great
cul-de-sac.   They all  approach  it  between the laminae  of its
omenta,  and  undergo many divisions and subdivisions in the
cellular coat;  they at  length  terminate by forming  a very fine
and delicate vascular  arrangement  in the  substance of the mu-
cous membrane,  and  when  successfully  injected give  to the
latter a thorough tinge of red.  The veins follow the  course of
the arteries, and  like them  have frequent anastomoses, but are
larger; they terminate either directly or indirectly in the trunk
of the  Vena Portarum.
   The nerves of the  stomach come from the Par Vagum, and
from the semi-lunar ganglions of the Sympathetics.
   Its lymphatics arise from both the external and the internal
surface, and their trunks having  to pass first of all to the lym-
phatic glands situated  along the curvatures, afterwards empty
into the thoracic duct. 
28
ORGANS OF DIGESTION.
            SECT. II.--OF THE INTESTINAL CANAL.

  The Intestinal Canal is from thirty to thirty-five feet in length,
and extends from the pylorus to the anus.  Owing  principally
to a well  marked  difference in  magnitude, it is divided by ana-
tomists into the Small and into  the Large intestine.


                     Of the Small Intestine.

  The  Small Intestine  (Intestinum  Tenue) commences at the
pylorus, and  terminates in the right  iliac region by a lateral
aperture into the large intestine.  It is four-fifths of the length
of the whole canal, and measures from  twenty-four to twenty-
eight feet.*  When  moderately distended its diameter is about
one inch.  It retains from one end to the other an uninterrupt-
ed cylindrical shape, with-the exception that if the two ends be
compared, the upper will be found larger than what is stated as
the medium  measurement, and  the lower smaller; or, in other
words, the intestine decreases  successively from  above down-
wards, and, as a whole,  is slightly conoidal, though this diminu-
tion is so gradual  that it is not perceptible in any short space.
  The Small Intestine, like the stomach,  consists of four  dis-
tinct  coats, the  peritoneal, the  muscular, the cellular, and  mu-
cous.
  The Peritoneal Coat is complete,  and forms the external sur-
face.   It is continued afterwards  in  two laminas from the intes-
tine to the lumbar vertebras, thereby constituting  the Mesente-
ry.    The two laminas, where they depart from the intestine, are
loosely connected with  each other, for  the purpose of allowing
room  for the  dilatation of  the  intestine, on the same  principle
which is exemplified in regard  to the stomach.
  The muscular  Coat is next  to  the peritoneal.  Its  fibres are

  * This is the generally received opinion of anatomists:  it would appear, how-
ever, to be applicable only when the intestine is left attached to the mesentery;
for ff it be cut off and straightened, it will measure thirty-four feet, which, added
to eight feet of large  intestine treated in the same way, will  amount in  all to
forty-two feet. If to  the estimate of this length we add what  is lost by the
doublings of the mucous coat, the entire length of surface must amount to nearly
sixty feet, at least, in many subjects. 
INTESTINAL CANAL.                   29
   pale, and form a lamina not so thick as common writing paper.
   The superficial ones are longitudinal, not very distinct, and too
   much separated to form a  perfect coat: they are  most abundant
   on  the anterior semicircumference or the one most distant from
   the  Mesentery.   The others all run in a circular direction, ap-
   proaching  to the spiral, and are sufficiently numerous to form a
   perfect coat: none of them perform a complete circuit of the in-
   testine, but are rather  segments of circles.   This coat is united
   to the peritoneal by a thin scattered cellular substance.
     The Cellular Coat of the small intestine, also called the  ner-
   vous, like that of the stomach, is only a lamina of dense cellu-
   lar substance, which serves as a medium of conrffcxion between
   the muscular and the mucous  coat; and also conducts to the
   latter the  blood  vessels, nerves, and  lacteals.  When inflated
   and dried, it puts on a beautiful cotton-like  appearance—as in
   fact the corresponding coat of other parts  of the  alimentary
   canal does the same.
     The Mucous Coat is the most internal, and when it has been
   cleaned by maceration, exhibits an opaque pearly colour.   It is
   remarkable for having its extent very considerably augmented
   beyond that of the other  coats; by being thrown into a great
   number of permanent  folds, or duplicatures, which lie one upon
   another successively, like  the shin«les upon the roof of a house.
   These duplicatures are the Valvulas  Conniventes, and are  for
   the most part about three lines  in breadth.  They are  either
   placed in the direction of the circumference of the intestine, or
   are very slightly oblique;  generally they go all around, but
    many of  them  are segments of circles, and by being arranged
   successively, their ends pass one another, or are connected by
   slight elevations.  They are more numerous and broad  in  the
   upper than in the lower half of the intestinum tenue, and are
•  evidently intended to retard the progress downwards of alimen-
   tary matter, and to increase the surface for absorption and for
   exhalation.
      The mucous membrane, on  the side which it presents to the
   cavity of the intestine, is  furnished with  a great number of de-.
   licatc cylindrical projections, resembling the down on the  skin
   of an unripe peach, and called Villi,* from whence the term vik
     * This is intended merely as  an expression of the common and received no-
   tion, my own views arc exhibited in the minute anatomy of this coat.  Sect. hi.
                                4* 
30                  ORGANS OF DIGESTION.

lous has also been applied to this coat.  These villi are to be
found in abundance every where;  but in the upper half of the
intestinum tenue they are so numerous as to stud its whole sur-
face, and to be in contact with each other.  They are from
one-fourth of, to a line in length; and some of them, when exa-
mined with a microscope, appear  flattened  and fungiform.
According  to the estimate of Meckel,* where they are thickest,
every square inch of intestine furnishes about  four thousand of
them, and  by extending this computation, with a proper al-
lowance for diminished numbers below, their aggregate amount
is about one million.f
   Each Villus is composed of an artery, a vein, and a lympha-
 tic; all united by cellular substance.   From  the extreme vascu-
 larity of the mucous membrane, the blood vessels readily re-
 ceive a fine injection  and thereby become evident, forming a
 very delicate vascular net-work in each of the villi.  It is ascer-
 tained that the lymphatic opens on its surface, but whether by
 one or more orifices is  yet unsettled.  According to the cele-
 brated Lieberkuhn, there is commonly but one orifice at the end
 of each villus, and very rarely two: this assertion he considered
 himself as having established by passing a current of air through
 the villus till it was dried, and then slitting  it open.  Hewson,
 Cruikshank, and W. Hunter, on the contrary, are said  to have
 found many more, amounting even to twenty, on such villi as
 were gorged with chyle.   The subject has been fruitful with
 controversy to anatomists, and ranks many distinguished cham-
 pions on each side; but as from the minuteness of the parts un-
 der discussion and  the consequent  necessity of microscopical
 observations, it is exposed to much fallacy and illusion; and can-
 not  be  satisfactorily settled, though the  general analogies of
 papillary structure are in favour of the latter authorities.  The
 more important  fact, however, is conceded  by the  admission
 of all, that there is a branch of the lymphatic system in every
 villus; which has, for its function, the absorption of chyle from
 the cavity of the intestine.

   * Manuel D'Anat.
   T This is probably much below their real number;  in an observation at the
 university we h-ive found the villi on the ilium at its lower part amounting to
 six thousand four hundred the square inch, as their  shape, however, varies very
 much, as we shall see, a rule eannot be derived from this. 
INTESTINAL CANAL.                    31
  An abundance of Mucous Glands is found deposited in the
cellular coat of the small intestine, between the muscular  and
the villous;  their ducts open upon the  internal surface of the
latter, in the interstices of  the villi, and from their smallness
require the intestine to be floated in water, and examined with
a magnifying glass, before they can be recognised.   In  order
to see the glands themselves, the intestine must be cleaned  by
soaking it in water; it is then to be slit open longitudinally, and
held between the eye  and the  light, in which  case the glands
appear like little points or spots in the thickness of the intestine.
They are more abundant in the beginning of the latter, decrease
about its middle, and  increase again  towards  its termination.
Their structure is very simple, as they consist in  a  congeries
of blood vessels, terminating in short canals secreting mucus.*
  Some of these glands are microscopical, and are called cryptas;
others are to be found  from that size to a line  in  diameter, and
flattened.  They are either  alone or in clusters.  The former
(GlandulcB Solitaries, Brunneri,) are found principally about the
duodenum and the neighbouring portion of the small intestine,
but also exist all the way down in a  scattered manner.  The lat-
ter (Glandular Agminatce, Peyeri,) exist principally in the lower
part of the small intestine, and are collected into  clusters vary-
ing from a few lines to three  or four inches in length, but seldom
more than from eight to twelve lines broad.  They are, for the
most part, in elliptical patches, which, in a healthy state, may be
recognised rather by a slight discoloration, than by the more or-
dinary means, and are generall}' situated some distance from the
mesentery.  There are about  thirty of these clusters, of all sizes,
in the ileum, and they are placed nearer and nearer to one another,
in approaching the ileo-colic  junction.   All  of these muciparous
glands are too much flattened to project sensibly into the cavity
of the intestine, and, when they do, there is reason  to believe that
they are in a diseased  state, at least in the adult.   For the  most
part, in children, the glands of Brunner may be seen in the whole
length of the small intestine.

   The mucous  coat of the  small intestine is  every where ex-
tremely vascular.
Soemmering, dc Corp. Hum. Fabrica. 
32                  ORGANS OF DIGESTION.
  The Small Intestine, though an uninterrupted tube from  one
end to the other, is divided by anatomists into Duodenum, Jeju-
num, and Ileum.  There is some reason for the  first name, but
the two latter may be very conveniently blended, as has been
done by some, under the term Mesenteric Portion of the intesti-
nal canal.

  The Duodenum, named from  its being about twelve inches, or
twelve fingers' breadth in length, is nearest to the  stomach; or,
in other words, is the commencement of the canal.  It is sensi-
bly larger than either of the others, and is, moreover, suscepti-
ble of great dilatation, whence it has also been called Ventriculus
Succenturiatus.  Its direction is much varied: beginning at the
pylorus, it first of all passes upwards and to the  right side till it
reaches the neck of the gall-bladder; it then turns downwards,
so as to form a right angle with itself, and descends in front of
the right kidney to the third lumbar vertebra, being there placed
behind the superior lamina of the transverse  mesocolon.  It
then forms a round elbow, crosses  the spine obliquely, under
the junction  of the mesentery and  mesocolon, in ascending
from right to left; and making its appearance to the left of the
second lumbar vertebra, is  there continued into the mesenteric
portion of intestine.
   The beginning of the duodenum is moveable, and  has a pe-
ritoneal coat continued from the lesser omentum;  the descend-
ing and the transverse portions  have no proper peritoneal coat,
but are only loosely fixed between the laminas of the mesocolon;
the termination is both moveable and has a peritoneal covering,
from being at the commencement of the mesentery.
  From the course  assigned to the duodenum, it is evident  that
it forms the segment of a circle, the concavity of which looks to
the left side.   This concavity is occupied by the head  of the
pancreas.   The transverse portion crosses the  spine below the
latter, and is separated from it by the superior mesenteric artery
and by the vena portarum:  behind it  are  the crura of the  dia-
phragm, the ascending cava, and the aorta.
   The organization of the duodenum  is the same with  that of
other portions of the intestinum  tenue.   Its peculiarities consist
only in a partial deficiency of  peritoneal  coat, and in its auo--
mented size.   Its internal or mucous coat  is very much  tino-ed 
INTESTINAL CANAL.
33
with bile, abounds in valvulas conniventes, and about four inches
from the pylorus is marked by a small tubercle or elevation, in-
dicative of the orifice of the biliary and of the pancreatic duct.
The Glands of Brunner are very conspicuous in this intestine,
and are so  numerous near  the pyloric orifice, as to form with
some a perfect layer, and  to give  it a granulated appearance
for two  inches or more.  These glands are considered by Mr.
Cruv.eilhier and Boehm to be pancreatic in their structure.
   The Jejunum  and  Ileum form the  remaining length of the
small intestine, and have no external marks of difference  from
each other.   They are strung along the mesentery, and, in con-
sequence of their great length, are thrown into folds or convolu-
tions, which give to them a complicated appearance.  There is,
however, no difficulty in tracing them regularly from one end to
the other.  They occupy the umbilical, the hypogastric, and a
part of  the iliac regions, and are surrounded by the circuit of
the colon.   The upper two-fifths is the jejunum, and the lower
three-fifths, the  ileum.  This distinction, originally introduced
by Galen,* from a supposition that the jejunum was more fre-
quently  found empty than any other intestine, has no rigid ana-
tomical support.  The only difference between the two is, that
the valvulas conniventes, abundant in the whole length of the je-
junum, become less so at the upper part of the ileum, and finally
disappear entirely towards its lower extremity. The distinction
has, therefore, been rejected by the most approved modern au-
thorities, such as Haller, Soemmering, Meckel, and so on.
   It sometimes  happens, that the intestinum tenue  has one or
 more blind pouches appended to its sides and opening into its
 cavity.
   The  small intestine is supplied with blood from the  superior
 mesenteric artery.   Its nerves come from the sympathetic.

   The  Mesentery (Mesenterium) is a process of peritoneum
which serves, as mentioned, to connect the intestinum tenue  to
 the posterior parietes of the abdomen, and extends its connex-
 ions from the left side of the second lumbar vertebra to the right
 iliac fossa.  This attachment, called the root, is about six inches
 in length;  whereas its lower circumference, which encloses the
* Portal, Anat. Med. 
34
ORGANS OF DIGESTION.
small intestine by giving it a peritoneal coat, is, of course, the
whole length  of the bowel, (duodenum excepted,) and, conse-
quently, from  twenty-three to twenty-seven feet in length.  This
expansion becomes intelligible the moment that the arrangement
of the part is  inspected, and is somewhat after the  manner of a
ruffle, except that it is not puckered at the root.
  The two laminas of peritoneum which form the mesentery,
contain between them the superior mesenteric artery, and the
corresponding portion of the superior mesenteric vein; an abun-
dance of lymphatic or lacteal glands and vessels; ramifications
from the solar plexus of the sympathetic nerves; and a considera-
ble quantity of cellular and of adipose tissue.   The superior la-
mina is continued directly into the mesocolon, and at the place
of junction  the transverse part of the duodenum is  very percep-
tible beneath.  The lower lamina descends along the posterior
parietes of the abdomen, concealing  the large blood  vessels
there and the ureters.
                   Of the Large Intestine.

  The Large Intestine (Intestinum Crassum) receives the effete
matter from the small, and is supposed also to make some pecu-
liar secretion of faecal matter from its internal surface.   It ex-
ceeds much in its diameter the small intestine, and differs also
from it in not being by any means so regularly cylindrical.  It
commences at the inferior end of the small intestine, and termi-
nates  at the anus, describing in this course, as mentioned, a cir-
cle which surrounds two-thirds of the abdomen, and embraces
the intestinum tenue.  Like the latter, though only a continuous
tube, it is divided  into three parts;  the  commencement of it,
which is  below the insertion of the ileum, and about two inches
in length, is the Ccecum, or Caput Coli; the remaining portion,
which occupies  almost  its whole length, is  called the  Colon,
until it reaches the pelvis, when the  name  is  converted into
Rectum.

  The Mesocolon is a reflection or duplication of peritoneum,
that fixes the large intestine to the posterior parietes of the ab-
domen.   This duplicature is not of a breadth so uniform as the 
INTESTINAL CANAL.
35
mesentery, but allows to the middle of the large intestine very
considerable motion, up and down, according to the distention
of the stomach, while the lateral portions are very much confined.
For example, in the right iliac  fossa the mesocolon is so short
that the posterior surface of the gut is in contact with the iliac
fascia, and adheres to it by loose cellular substance; in the right
and left lumbar regions the bowel is immoveably fixed in front
of the kidneys, but in the space between these two points, that
is to say, where the bowel traverses the hypochondriac and  the
epigastric or umbilical regions, the peritoneal attachment, here
called, from its situation, the  transverse  mesocolon, is so long
and loose that  it forms a complete and moveable septum between
the small intestine and the stomach.  In the left iliac region,
again, the large intestine, after having been bound down to  the
left lumbar, is  suddenly loosened by an increased breadth of the
mesocolon, which permits it to form a large convolution, called
its sigmoid flexure.   The mesocolon  is then continued into  the
pelvis in front  of the sacrum, first of all a little to the  left of  the
middle line of the latter, and,  as it descends,  it gets directly in
front of the middle line.   The  portion of it in the pelvis is called
mesorectum, after the gut which it serves to attach.
  The composition of the mesocolon is precisely the same with
that of the mesentery, though  it be not so thick:  it, therefore,
consists in two laminas of peritoneum, which contain between
them some adipose and cellular matter, along with the arteries,
the veins, the  nerves, and the  lymphatic vessels and glands  be-
longing to the large intestine.

   When the large intestine is inflated, it is rendered very  ob-
vious that  it decreases in size  from its commencement  to  the
lower part of  the sigmoid flexure, it then increases again in size
just above the  anus.  Its surface is arranged into three series or
longitudinal rows of projections, separated by transverse depres-
sions, the whole corresponding  with an internal cellular arrange-
ment, by the latter surface being the reverse  of the former.
   Its coats, like the small intestine, are four in number; the pe-
ritoneal, the muscular, the cellular, and the mucous.

   The Peritoneal Coat prevails in its whole extent, with  the
exception of the lower part of  the rectum: on  the ascending  and 
36
ORGANS OF DIGESTION.
the descending portions of the colon, however, where the latter
comes in contact with  the parietes of the abdomen, the perito-
neum does not invest it entirely;  but the transverse portion or
the arch, as it is called, and the sigmoid flexure, are completely
surrounded.
  The surface of this intestine is studded with small projections
of various lengths, called Appendices Epiploicas, which are small
duplicatures of peritoneum containing fat.

  The Muscular Coat is thin, and like that of the small intestine,
consists of two orders of fibres, the longitudinal, and the trans-
verse or circular.
  The longitudinal fibres have the peculiarity of being collected
into  three equidistant, flattened fasciculi or bands, of about half
an inch in breadth, which begin by a common point at the ex-
tremity of the ccecum, and extend to the upper end of the rec-
tum.  One of them is along the line of junction with the meso-
colon, another anterior, and the third inferior.   These  fibres,
being shorter than the  other coats  of the gut, have the effect of
puckering them into the internal cellular condition alluded to;
for, when  they are cut  through, the intestine is much elongated,
and its cells disappear.   It occasionally happens that the longi-
tudinal fibres, instead of being confined to the bands alluded to,
exist in considerable quantity  over the intermediate spaces; in
this case the cellular arrangement is restricted, and in some in-
stances entirely  dispensed with; of the  latter,  an example is in
the Anatomical  Museum.
  The circular muscular fibres form a thin semi-transparent la-
mina beneath  the last, and do  not present any peculiarity of in-
terest, they are somewhat thicker than in the small intestine.

  The Cellular Coat is  a thin lamina of dense cellular substance,
serving to connect the  muscular with the mucous coat, and to
conduct the blood vessels and nerves to their terminations on
the latter.

  The Mucous Coat lines smoothly the internal face of the cel-
lular, and has no doubling or folds, exclusively in  it, like  the
valvulas conniventes of the small  intestine.*  The  transverse

  * This may be considered as the general rule: if it be examined, however, in
its whole length, here and there narrow ones may be found. 
INTESTINAL CANAL.                   37
projections which it makes between the longitudinal bands, into
the cavity  of the gut, and which separate the cells of the large
intestine from each other, are not mere duplicatures of it alone,
but are also constituted by the other coats.
   Near its commencement this coat has the fungous appearance
of the stomach, but about the sigmoid flexure it has a plain,
smooth, and, to a degree, a polished  surface.  It  has but few
villi, such as exist in the small  intestine; indeed, some anato-
mists deny that it has any.  Its muciparous glands and follicles
are numerous, and the former, when  somewhat enlarged, pro-
ject; they  are unusually conspicuous about the sigmoid flexure,
and" in the rectum.   Its lacteals  are not abundant.
   The mucous coat of the large intestine is very vascular, but
not so much so as that of the small intestine.
   Each  division  of the large   intestine  has  some peculiari-
ties of structure and  connexions;  which may now be attend-
ed to.

   The Ccecum, or Caput Coli, is generally from an inch and a
half to two inches long, has a rounded termination below and
somewhat  to the  left, from which proceeds an  intestinal pro-
cess, the Appendicula Vermiformis.  The latter is from three
to four  inches long, is cylindrical,  has a diameter of two or
three lines, and consists of the  same number of coats, having
the same structure with other portions of the intestinal canal;
its base is  the point from which the  three longitudinal  bands
start.  It is attached  by a narrow  duplicature of peritoneum,
a process of the mesentery, which permits it  to float loosely in
the abdomen.  It seldom contains fasces, but is  kept distended
by flatus.
  The ccecum, as mentioned, is,  for the most part, confined in
the right iliac fossa, but we very frequently see it with a renp-tfi
of peritoneal attachment permitting it to descend for a short
distance into the pelvis.

  The lleo-colic  Valve  (Valoula Bauhini)  is  formed at the
junction of the ileum with the caput coli.  This valve, destined
to prevent  the return of fascal matter from the  large into the
small intestine, consists in a transverse elliptical opening, or
slit, whose  lips become approximated in the  distentions of the
  Vol. II.—5 
38
ORGANS OF DIGESTION.
colon.   The ileum runs into the left wall of the large intestine,
and continues its cellular and  mucous coats  into the corre-
sponding coats of the latter.  The circular muscular fibres of
the large intestine separate to a certain  degree to j>ermit this
introduction, but their farther separation is restrained at  each
commissure or corner of the lips, by a  lending of the struc-
ture, aided by a few .ligamentous  fibres, designated as the re-
tinacula of Bauhin  or of Morgagni; which, however, are fre-
quently not very distinct.  This separation  is  also restrained
by the  two longitudinal bands between which they are inserted,
one of which  is at the posterior commissure, and the  other
only a  short distance off from the anterior.   The lips them-
selves,  formed principally by  the mucous membrane, approach
one another after the manner of  the ship dock or canal gate;
the superior  is somewhat broader than  the  inferior.   Their
power, as well as their existence, depends entirely on the ten-
sion which is kept up by the  natural connexions of the parts;
for a very slight dissection causes them to become almost ef-
faced,  and instead of forming an elliptical transverse opening,
to be converted into a round  patulous one.

   The Colon, properly speaking, has some regional distinctions
which  are serviceable to accurate description.  The right lum-
bar colon, which is  bordered in front by the small intestine, and
behind, by the right kidney,  extends from the ileo-colic valve,
to the  margin  of the false ribs of the corresponding side.   The
transverse colon, bordered above by the  stomach, and below
by the small intestine, goes from  one hypochondriac region to
the other.  It is generally found more distended than the other
portions.   The left  lumbar  colon descends from the  hypo-
chondriac region of the left side to the sigmoid flexure,  being
bordered behind by the left kidney, and in front by the  small
intestine.   The sigmoid  flexure, placed in the left iliac  fossa,
forms  a convolution, but is very indifferently described by the
term applied to it.  It is occasionally  very long and loose, and
terminates at  the left  sacro-iliac symphysis.   It  is not  unfre-
quently found destitute of the partitions which prevail in other
parts.
The Rectum  begins  at the left sacro-iliac symphysis,  and 
INTESTINAL CANAL.
39
passes obliquely  downwards to  the  centre  of the  sacrum,
thence in front of the middle line of the sacrum, and of the
coccyx, to terminate at the point  of the latter.  It is not regu-
larly cylindrical, but, just above  the anus, is dilated into a wide
pouch, flattened from before  backwards by the pressure of the
bladder,  and very distinguishable  upon the introduction of the
finger, for it is but seldom in  a contracted state.  It, of course,
has a flexure by  adapting itself to  the concavity of the sacrum,
and is bounded in front by the bladder, the prostate gland and
the vesiculae. seminales of the male, and by the vagina and the
uterus of the female.
   The peritoneum covers  only the superior  two-thirds  of the
rectum, and attaches it by the short duplicature, called the me-
sorectum, to tfie  front of tiie  sacrum,  A small pouch, passing
down between the vesiculas seminales almost to the base of the
prostate, is  formed, as  mentioned previously, by the peritoneum
in its course from the rectum to  the bladder.
   The muscular  coat of the rectum has a thickness and redness
surpassing much that of any other intestine, and is divided very
clearly into  two  laminas, the  external of which consists in lon-
gitudinal and the internal in circular fibres.  The external forms
in itself a complete coat continuous with the longitudinal bands
of the colon, but is much increased  by additional fibres.   The
circular  fibres also form a complete  coat, and, just below the
pouch of the rectum, are multiplied  so  much for eight or  ten
lines  as  to  be a perfect internal  sphincter  muscle, bearing a
strong analogy with  the  pyloric muscle of the stomach.*   At
the anus, an arrangement of the muscular coat prevails, which,
as far as I know, has not been heretofore attended to by anato-
mists.  The longitudinal fibres, having got to the lower margin
of the internal sphincter, turn under this  margin between it and

  * It has been recently asserted that there is also a sphincter muscle four inches
above the anus, half an inch wide in front, and one inch wide behind, from whence
according  to Mr. Velpcau the fibres go in crossing one another to fix themselves
to the front of the sacrum.   Mr, Lisfranc appears to have first announced it and
Mr. Nelaton to have described it. Malgaigne, Anat. Chirurg. vol. 2d, p. 343. Paris,
1838.  I doubt very much the uniformity of the distinct existence of such a mus-
cle, not having been  able to find it in the dissections which I have instituted for
the purpose, unless a portion of the ordinary circular fibres should have been se-
lectcd for that designation. 
40                  ORGANS OF DIGESTION.

the external sphincter, and then ascend upwards for an inch or
two in contact with the mucous coat, into which they are final-
ly inserted by fasciculi which form the base of  the columns of
the rectum; many of the fibres, however, terminate also between
the fasciculi of the circular fibres.   This connexion must have
obviously much influence in the protrusions of the mucous coat,
which sometimes take place.
   The  mucous  coat of the rectum is  thick, red, and fungous,
and abounds in mucous lacunas and glands.  It is smoothly laid
above, but below it is thrown into superficial longitudinal folds
called columns.  At the lower ends  of the wrinkles, between
the  columns,  are  small  pouches of from  two to four  lines in
depth, the orifices of which point upwards; they are occasional-
ly the seat of disease, and produce, when enlarged, a  painful
itching.   An original observation of Dr. Physick, on the nature
of this affection, and the remedy for which consists in  slitting
them open or removing them, induced me  to look for  the ordi-
nary natural  structure, which I have  found  to  be as  now de-
scribed.*  The wrinkling  of  the anus is from  the  influence of
the  external  sphincter  ani  muscle.  In  some  subjects, large
cells are  formed in the cavity of the rectum by transverse
doublings of the mucous coat only, resembling the valvulas con-
niventes of the small  intestine;  this, however, is  not the most
frequent arrangement,  though deserving  of notice.  It takes
place under the following mechanism.
   About a finger's length from the anus there is  a puckering of
the gut, or deep wrinkling, such as occurs in the colon, and it
arises from a similar cause, that is, an abbreviation of the lon-
gitudinal layer of fibres  of the gut: this abbreviation is  not cir-
cular, but occupies the semi-circumference of the gut on  one
side, and then a little higher up, the semi-circumference of the
other side.  This shortening  of the gut "brings the fasciculi of
its  circular muscular  fibres  more together, and, therefore, ac-
cumulates them into a greater thickness.   At a  corresponding

  * See an interesting paper on Fistula in ano, by M. Ribes, in Mem. de la So-
ciete D'Emulation, vol. 9, 1826; where the influence of this structure is alluded
to.-It appears that Glisson and Ruysch first described them as valves  Also
an elaborate and excellent article,  by Dr. Reynell Coates, in the Cyclopedia of
Pract. Med. and  Surgery, Philada. 1835, under the term anus      ? 
ANATOMY OF THE MUCOUS COAT.
41
part on each side of the gut in its  interior, exists a  transverse
doubling of the mucous coat forming the valvulas conniventes al-
luded to.   The result of this arrangement is a  semi-circular
valve on each  side, one  above the other, the margins of which
pass each other in the empty and contracted state of the rectum,
but touching at the same time, and they present an  additional
barrier  to the involuntary evacuation of fasces.*
  The large intestine is supplied with blood from a part of the
superior mesenteric, from the whole of the inferior mesenteric,
and from the internal pudic artery.   Its veins empty into the
vena portarum.   Its nerves are derived from  the  solar and the
hypogastric plexus of the sympathetic.

SECT. III.—ON THE MINUTE ANATOMY OF THE MUCOUS COAT OF
                  THE ALIMENTARY CANAL.

  In the preceding account of the mucous coat of the stomach
and bowels, I have admitted the most generally received  opi-
nions, as it is in every way proper for medical men  to be aware
of them.  Having been,  however, much occupied, a few years
ago, in  ascertaining the pathology of Asiatic cholerat by dissec-
tions, the  observations which I then made upon the healthy  and
diseased structure have  induced  me  to modify very much  my
former  views, as will be seen in  the following pages.
  The mucous coat of the alimentary  canal, in a healthy state,
and successfully injected, appears to consist almost entirely of
a cribriform intertexture of veins.  These veins being commonly
empty at  death present themselves as  a  soft  spongy structure,
which gives rise to the ordinary description of its sensible con-
dition as a velvety layer.  The most minute injection of the ar-

  *  It has latterly been advanced by Mr. O'Beirnc, that in a natural state the
rectum is empty, and that the accumulation of faces preparatory to a stool occurs
in Uic sigmoid flexure of the colon, where they arc retained by a contraction ef
the upper end of the rectum.  The principal ground of this opinion is, that fecal
matter is rarely met with in the rectum.   The observation is so contradictory to
my experience in the dissecting room and on patients, that I cannot but reject
it, though it appears to be obtaining some currency, or at least is quoted respect-
fully. Journal Ilebd. IS33,  vol. xiii. p. 126.  Malgaignc,  Anat. C'hir. vol.
■2d, 311.
  f  Amcr. Jo.urn Med. Sciences for Vol. xvj. May, 1835.
                              5* 
42                  ORGANS OF D1CESTION.

lories scarcely makes itself visible, among these veins when they
are properly injected, a straggling branch only here and there
exhibiting itself.   The arboresccnce of the arteries is confined
to the level beneath the venous intertexture, and is there deve-
loped to an  extreme  degree of minuteness, being intermixed
with corresponding venous ramuscles, generally larger and more
numerous than the arteries themselves. This arrangement seems
to occur in the surface of the cellular coat which makes  the
base or ground of the mucous.  The fine venous trunks of  this
deeper layer have their originating extremities bent vertically
towards the  cavity of  the gut, and by that  means receive the
blood of the  first venous intertexture or layer, as the petrous
sinuses join the cavernous, or the  veins of the penis arise from
its spongy structure.   The meshes of  the  first venous intertex-
ture are exceedingly  minute, and  vary in a characteristic man-
ner in the stomach, small intestines and colon.  This  intertex-
ture is very different in its looks from  a common vascular anas-
tomosis, and produces in  the  colon an appearance resembling
a plate of metal pierced with round holes closely bordering upon
each other;  these holes constitute, in fact, follicles or  gaping
orifices,  the edges of  which are rounded off', and their depth  is
that of  the thickness of the venous anastomoses; being bounded
below by the arterio venous layer, and by the cellular coat of
the part.  Nothing short of an entirely successful injection  will
exhibit  this venous anastomosis  as described;  and it may be
seen either by injecting a vein, or an artery provided the injec-
tion passes from the artery, into the veins, but the latter process
is the least desirable, because we  lose the  benefit  of a distinc-
tion of colour between the two sets of vessels.
   Ordinary modes of examination give no evidence of the exis-
tence in the alimentary canal, from  the  cardiac orifice of the
stomach to near the anus, of an epidermis; on the contrary, they
rather lead to a belief of its being  absent, in consequence of the
softness, tenuity,  and transparency of the  mucous membrane;
but that it is really present, may be  proved by the following
process:—Tear off the peritoneal coat  of a piece of small intes-
tine-mverl the part and inflate it to an emphysematous condi-
tion;  the epidermis will then be raised as a very  thin pellicle
and  may be  dried in that state; but as this pellicle retains the
air, we hence infer that it  lines the follicles, and is uninterrupted 
ANATOMY OF THE MUCOUS COAT.
43
by any perforations.  This epidermis, if the part be previously
injected perfectly, shows dots of injecting matter like those left
in the rete mucosum upon a minute injection of the skin, but no
arborescence if it be raised up from  the veins by  the inflation
stated.  In so doing the villi disappear, are in fact unfolded.
   The villi cannot  be seen  to any advantage except they be
erected by an  injection, in which case those of the upper part
of the small intestines are found to run into each other very
much like the convolutions of the cerebrum, and  to press upon
each other's sides in the same way.   Some of them, however,
 are  merely semi-oval  plates, the transverse diameter of which
 exceeds the length or elevation.  At the lower end of the small
 intestine they  become  simply conical projections, somewhat
 curved,  with the edges bent  in or concave,  and they retain this
 mechanism until they entirely disappear near the ileo-colic valve.
 In  the  whole length of intestine  there  is,  however, every
 variety of shape, from oblong curved and serpentine ridges, to
 the laterally flattened  cone  standing on its base; the first condi-
 tion changing  gradually to the last in the descent  of the bowel.
 Conformably to this definition of villi, none  exist either in the
 stomach or colon,  for there we  have only the  venous mesh.
 The villi of the jejunum are about the thirtieth of an inch high,
 and those of the ileum about one-sixtieth.
    In the ileum, the superficial venous layer has great regularity
 and the conical villi stand out beautifully from its anastomoses, or
  in  equivalent language, from the divisions of the follicles.   In
  the upper part of the small intestine  the follicles are  in equal
  number to what they are in the ileum; the regularity  of their
  arrangements being interrupted by the long serpentine  and oval
  villi; but  invariably  the same venous intertexture exists  and
  forms, in both, the chief bulk of the villi, by passing into them.
     In the stomach the follicles  vary much in size, and there is
  an arrangement whereby many of the smaller ones are seen to
   open into the larger: on  an average about two  hundred  and
   twenty-five are found upon every square of One eighth of an inch,
   which would  give of course to an inch square sixty-four times
   that amount, or fourteen thousand  four hundred follicles; and
   conceding the  whole stomach to  present an  area of  ninety
   inches, which is probably below the mark when this organ is
   moderately distended, as  exhibited in the preparation upon 
44
ORGANS OF DIGESTION.
 which this calculation is founded, the entire number of follicles
 is one million two hundred and ninety-six thousand.
  The great uniformity of size of these follicles in the colon,
 and  its even surface, enable  us to count them with more cer-
 tainty, and they appear to exist at the  beginning of this gut at
 the rate of about four hundred for every eighth of an inch square,
 but in the sigmoid flexure  at the rate of about two hundred to
 the same area; they become, in fact, both smaller and less nu-
 merous in descending  towards the anus.   Their average  may
 be stated, therefore, as three hundred for every one-eighth of an
 inch square—and as nineteen thousand two hundred for ever}7
 inch square.  Admitting the entire area of the colon to be five
hundred  inches, and nineteen  thousand  two hundred of  these
follicles,  to exist on every  inch square, the aggregate number
 will be nine millions six hundred and twenty thousand.
  Again, estimating the whole  area of the mucous coat of the
 small intestines at fourteen hundred and forty  inches, and al-
lowing for interruptions  occasioned by villi, about three hun-
dred and ninety follicles exist upon every one-eighth of an inch
square, or 2 4.960 upon an  inch:  say then, that about twenty-
five thousand follicles are found upon  every square inch, and
 the two numbers multiplied, produce thirty-six millions.
  The entire number of follicles in the whole alimentary canal,
is, by the preceding estimates, forty-six millions nine hundred
thousand, and upwards.  I  am very far  from pretending to
have counted them all, but  have made an approximation to the
actual number by  observing sections of different porlions of
the same subject,  and verifying  the observations upon other
subjects.
  The external surface of the cutis vera presents, as  it were,
in outline the same follicular arrangement; the venous  reticu-
lar  intertexture appearing  broader,  not quite so  perfect, and
more  shallow, and forming  the papillae;  but as additional expe-
periments are wanting, it may  be passed  over with this  tran-
sient notice; perhaps, indeed, a more skilful hand  in adopting
the hint may perfect the details.*

  * It U probably this which constitutes the  bio .<ly  pimples (bourgeons san-
guins) of the skin. 
ANATOMY OF THE MUCOUS COAT.
45
  In the stomach, the largest of these  follicles  is about one-
ninety-eighth of an inch in diameter, and the smallest about
one-four hundred  and ninetieth.  In the colon the  largest is
about one-two hundred and forty-fifth of an inch in  diameter,
and the smallsst about one-four hundred and ninetieth.   In  the
small intestines their size varies in about the same ratio as in
the colon, but they are much more  irregular  in shape, being
scattered more in groups, in consequence of the villi interve-
ning: some  of  them penetrate obliquely towards  the founda-
tions  of the villi;  hence,  when  examined from the exterior,
their distribution is more regular, and they are seen  lodged in
the cellular  coat of the gut.
   I have endeavoured to keep the estimate of the number of
follicles below what other calculators would make it upon  an
observation  of my preparations, and a fair measurement of  the
area  of the alimentary canal, lest the number may seem  ex-
cessive and  incredible; I  have, therefore, the  most reasonable
assurance of being within bounds  on that point.   I  may now
ask their use; is it to  secrete or absorb?  If  they are simply
secernents  of  mucus, the number, one  would think,  much
greater than so limited a secretion requires—moreover, why is
it that  they become smaller  and less numerous towards  the
lower end of the large intestine, where greater  lubrication is
required for hardened fasces;  in addition, are not the glands of
Brunner, (solitaries,) and  of  Peyer, (agminata,) amply  suffi-
cient to furnish the required mucus?  Again, after most sedu-
lous observations upon the villi of all kinds, finely erected  by
my injections,  and placed under  most  accurate,  simple, and
compound microscopes, I  find, invariably, a polished  reflecting
surface, uninterrupted by foramina, either at their ends   or
sides, while many of these follicles are found passing obliquely
into their bases.  An excellent Woollaston's  doublet, which
makes the villi of the ileum appear an inch long, exhibits them
with  a  polished translucent surface, without foramina, except
where a villus from accident has been broken, a contingency
readily recognised by one in  the habit  of viewing them.   Fi-
nally, if the lacteal foramina of Lieberkuhn and others, do  re-
ally exist, why is it that the raising of the intestinal epidermis,
by inflation, does not exhibit these foramina by the air escaping 
46
ORGANS OF DIGESTION.
through them,  but, on the  contrary, admits of a dried prepa-
ration in that state, the villi being completely effaced.*
  Taking into  consideration these several objections to the the-
ory of the follicles being  secreting orifices, it appears to  me
that a better idea of  their use is called for,  which  suggestion
is submitted to the profession, with the hope that a more  ca-
pable person will remove the difficulty, by additional confirma-
tion of preceding  theories, or by the invention of a new one:
for my own part, I am  much inclined to adopt the opinion of
their absorbing  faculties.  It is generally conceded that  the
erection and prehension of the  Fallopian tube is produced by
a vascular turgesccnce, in  which the  veins, from their number,
must execute an important part; in like manner, as these folli-
cles are formed  in the  midst of veins, their orifices only be-
come erect and  patulous  by the distention of those veins,  and
cannot be seen, especially in  the small intestine, unless  an in-
jection has succeeded fully; but the erection of these veins du-
ring digestion puts the follicles in a similar condition; there is,
therefore, some ground of inference, that  the act of the Fallo-
pian tube in conveying a germ, and of a  follicle in conveying
into the thickness of an intestine congenial matter, may be
analagous.
   Notwithstanding the facility with which we can detect these
follicles, Ihave failed entirely under various  means of exami-
nation,  in finding any orifices to Peyer's glands, in the dried
intestine: they  appear to be merely small lenticular excavationst
in its substance, and wherever a cluster of them exists, it dis-
turbs the arrangement of the villi, and gives  to them a scatter-
ing unequal distribution.   I would  also  suggest very respect-
fully to anatomists whether our knowledge in  regard to them
is sufficiently exact to render farther inquiry useless? for my
own part it appears  that this subject  requires some additional
attention.
   The  above view, relative to  the structure of mucous mem-
  * In these and  other microscopical observations, I owe much to  my young
friend, now Demonstrator of Anatomy,  Dr. Paul Beck Goddard, who has ac-
quired an accuracy and skill in such matters deserving of confidence.
  t This observation has  been confirmed in Germany by Boebm, who has  come
to the same conclusion.  He says that they contain a white milky and rather
thick fluid, with numerous round corpuscles of various size, but mostly smaller
than blood globules.  Am. Journ.  Med. Sc. vol. xxi. p. 218. 
ANATOMY OF THE MUCOUS COAT.
47
 brane, presents at least  a degree of novelty, by determining,
 with some precision, the whole number of the  Gastro-enteric
 Follicles of the human body, and how they are in  every instance
jormed by meshes of veins, while the arteries enter only incon-
 siderably into its  composition, to an amount in  some measure
 comparable to the presence of the arteries in other erectile tis-
 sues, as the corpus spongiosum and cavernosum  penis.  In the
 latter  it is  familiar  to  every  practised  anatomist,  that  the
 branches of the arteries are but small, as they terminate in the
 cells of the penis, which are to be considered as only a modi-
 fication of the incipient stage of venous trunks.  If the corpus
 spongiosum were in fact spread out into a thin and single mem-
 brane, so as to line  a hollow viscus, it would present no very
 undue representation of what I  have denominated the superfi-
 cial venous layer of the alimentary canal; it being also admitted
 that within the circuit  of every anastomosis,  a follicle  was
 formed.  Viewed on the preparations of the mucous membrane
 of the small  and  large  intestines which I  have, these follicles
 appear like puncta lachrymalia disseminated by thousands over
 every inch square, and existing so invariably upon every part,
 that, as I have stated, the smallest calculation of their numbers
 puts them at from forty to fifty millions.
   It may now be  represented, that it is the whole of this vas-
 cular  and  follicular structure, endowed with vital actions  the
 most  important to life, and presenting in the aggregate an area
 of about thirteen square feet, the size of a small breakfast ta-
 ble; whose morbid derangements constitute the essential fea-
 tures  of cholera.  It has been shown in some of my dissections,
 that this apparatus  in the progress of cholera is detached en-
 tirely from the stomach and colon, in consequence of theexces-
 sive actions  going  on in  them.   The  small intestines also, in
 some of my preparations, exhibit in patches a  similar pheno-
 menon; but as the entire observation has been presented to me
 in its true light only since the disappearance of the disease,  I
 have had no means  of ascertaining the extent  to which they
 suffer in this way.
    The anatomy of the muciparous system of the alimentary ca-
 nal unquestionably requires a more  exact attention than has
 been  heretofore bestowed upon it, especially so  as to distin-
 guish between that part which is really glandular, and the fora- 
48
ORGANS OF DIGESTION.
 mina or follicles now under consideration.  The following ex-
 tract will explain the difficulty which still exists in regard to a
 proper conception of the latter.
   "The mucous glands, called also follicles or cryptas mucosae,
 are to the membranes of that  name what the sebaceous follicles
 are to the skin; that is to say, folds of the  mucous membrane
 in  form of  a cul-de-sac, whose orifices open upon that mem-
 brane.   These follicles have  not yet been discovered over the
 whole surface of the mucous membrane; but here, as with the
 skin, analogy leads us to admit them.  It is not long since they
 have been discovered in the  pituitary membrane, where their
 existence had been denied.  Be this as it may, we shall use the
 same observation upon these  glands that was made on the se-
 baceous, viz. the impossibility of making an exact dissection of
 the capillary tissues does not  allow us to discover all the forms
 of  animal matter; but wherever a  particular  humour is found
 in a tissue, we are  forced  to  conclude that this  latter is orga-
 nized in such a manner as to  be able to produce it, and when
 in place of one humour we meet with many, we  must acknow-
 ledge that the tissue is complex.   Such  is precisely the case
 with the mucous membrane .of the digestive  canal, and espe-
 cially of the stomach, which could have a form of animal mat-
 ter calculated to furnish digestive juices, although no  gland
 destined to that purpose is discoverable."*  This desideratum
 of positive evidence, instead of the inductive, is clearly supplied
 by  my preparations.
  In infancy, especially, the  mucous  glands  have  a sensible
 thickness, which enables us to  see them, but the smallest of them
 require the aid of a  microscope, and appear to  have been de-
 scribed by Galeati.t  As the  paper  is not to be  had in any of
 the public libraries of this city, I can only quote  from it on the
 current authority of anatomical works.   In a note to the anato-
 my of  the human body by  Sir Charles Bell, article Intestine, it
 is stated as follows:—"It has been supposed that the fluids ex-
 creted  from  the surface of the  intestines were furnished by very
 minute foramina, (which are visible by particular preparations,)
in the interstices of the villi.   See the letter of Malpighi to the
 Royal Society of London on the pores of the stomach, and the
 *  Broussais' Physiology. First American edition, p. 419.
 j-  Be cornea ventricals et inleslinorum tunica.  Comm Bonon. 1745. 
ANATOMY OF THE MUCOUS COAT.
49
 paper by M. Galeati in the Bologna Transactions, on the inner
 coat, which he calls the cribriform coat.  The pores, according
 to Galeati, are visible through the whole tract of the canal, and
 particularly in the great intestines."  Meckel designates these
 as glandular bodies under the name of glandules mucosce, cryptcs
 minimal.  Another order  of  glands are  those of  Brunner.*
 They are readily found in the duodenum at all ages; and parti-
 cularly well in  infancy, as low down  as  the  ileo-colic  valve.
 The third order are the glands of Peyer, discovered in 1677.f
 The celebrated Ruysch appears also to have understood the exist-
 ence of the folliclesof the stomach, and Swammerdam to have had
 some idea of those of the small intestines,! and he calls them tu-
 buli glandulosi  intestinorum interiores.  I  may here remark,
 that the figure of the villi of the small intestines given by Hed-
 wig, in  his Disquisit. Ampullarum,  &c. 1797, and which ap-
 pears, from its introduction into Caldani's and M. Jul. Cloquet's
 Anatomy,  to have a classical value, is, judging from my own
 preparations, too much a work of the imagination, executed un-
 der probably some fallacious views of the part itself: a clustre
 of cylindrical villi, with holes at the ends, would be an anomaly, for
 those of the upper part of the intestines are either serpentine folds,
 as represented  in my preparations,  with branches running into
 contiguous folds; or semi-oval laminas; while those lower down
 are of a  flattened conical shape, somewhat bent, but in every in-
 stance they are destitute of what has been termed by Lieberkuhn
 an ampulla, and to my eye have uniformly polished surfaces,
 uninterrupted by foramina.
   Mascagni has also introduced views of a good kind in regard
 to the follicular structure of the stomach and colon.§  But it is
 to Sir Everard Home, that we are indebted for one of the  best
 papers on the glandular structure  of  the  stomach  of different
 animals.||
   As the real  muciparous glands  have an orifice leading into

  * Glandule intestini duodeni vel pancreas secundarius; discovered in 1715
 See Mangetus, Theat. Anat. where this paper is introduced with the plates illus-
trative of it.
  f See also Mangetus for the description from Peyer, with his plates.
  t Mangetus Theat. Anat. Vol. I. p. 310.
  § Prodromo della grande anatomia. Tab. xiii.
  1  Phil. Trans. 1807 and 1817; and also his Comparative Anatomy.
     Vol. II.—6 
50                  ORGANS OF DIGESTION.
each by the  admission  of anatomists,  the  follicles  described
commonly by them, are of this description, and are not compa-
rable  in number  to the follicles  found  in  the  venous  meshes.
The highest estimate of the number of  the former, as made by
M.  Lelut,fixes them at about forty-two  thousand*   In  consult-
ing many of the  distinguished modern  authorities  on this sub-
ject, there seems  to be scarcely any thing in the anatomy of the
intestinal canal which is  presented  in  a  more  indefinite way;
especially in  regard to  the small intestines, than the difference
between the follicles, properly speaking, and  the  glands; and
none of them, so  far as I know, have undertaken to approximate
the entire number of the follicles and to point out how each one
is the  centre of a  venous  anastomosis, is formed  by it, and
always exhibits itself in a collapsed state when the vein is not
turgid.-j-

SECT.  IV.—OF THE GENERAL ANATOMY OF  THE MUCOUS MEMBRANES.
   The extent of  the mucous coat of  the alimentary canal, and
the important and varied sympathies which it has with most
other parts of the body,  render useful  some remarks on mem-
branes of this kind generally.  Mucous Membranes are so called
from  the nature  of the secretion which they furnish:  and  the
term  having been first applied to the lining eoat of the nose, a
similitude of character has caused  its extension to that of other
organs.  The celebrated  Bichat, the founder of the science of
general anatomy, was  the first to adopt fully,  and to perceive
the value of  this  classification; since which it has been almost
universally received by anatomists.
   As the skin forms an external covering to the body, so mu-
cous membrane lines the  internal surface of the hollow vicera.
When  it is recollected  that  this membrane  forms [an  internal
tegument to  the whole alimentary canal, from the mouth to the
anus;  to all the  urinary  and genital apparatus;  to the whole
respiratory system, from the nose down the trachea and through-
out the lungs;  it will  be admitted that its extension  exceeds
much  that of the skin.

  * Bouillaud, Traite du Cholera, p. 256.
  t The anatomy of  the Gastro-intestinal mucous membrane has elicited several
goed papers in Europe since 1835, inclusive. They are rather confirmatory of
preceding observaitona than distinguished by novelties, and the venous anasto-
mosis does not seem to be understood or appreciated. 
GENERAL ANATOMY OF THE MUCOUS MEMBRANES.         51
  A mucous membrane presents two surfaces, one of which ad-
heres to the contiguous parts, and the other is free  by  being in-
ternal.   The adherent surface is attached by a cellular structure
somewhat condensed.  This cellular structure is principally re-
markable for its want of disposition to secrete fat into its inter-
stices;  a property of immense  importance,  as without  it,  ob-
structions would be continually  occurring to the destruction of
life: it is pervaded by a multitude of fine vessels and  nerves; run-
ning forward to be spent upon the  mucous membrane; and has
been unfortunately named nervous coat, by anatomists of high
authority.  The strength of attachment which it  furnishes is
somewhat varied; for  example, in the  small intestinal canal I
have often seen the mucous membrane caught at one  end and
entirely withdrawn from the muscular coat, an experiment which
alone can give rigid ideas of its greater length, as by it all the du-
plicatures or valvulas conniventes are stretched  out.   The ex-
periment succeeds much more certainly  by the regular pressure
of a  column of water between the  tunics of the intestine.   The
mucous membrane of most organs is arranged into wrinkles and
duplicatures, for the purpdse of augmenting its extent.  This ar-
rangement prevails in the nose,  and, as mentioned,  in the oeso-
phagus, in the  stomach and intestines; to say nothing of many
other instances which  are  noticed in the description  of each
organ.   In some examples, they are permanent, and, in others,
depend on the  state of contraction of an exterior muscular coat.
The interior face of the mucous membranes, allowance being
made for the inequalities just stated, moreover, presents, when
closely  viewed, an abundance of more minute depressions and
of elevations, causing it to resemble velvet.   Some of these de-
pressions are so large as to give  it a cellular appearance,* as in
many parts of  the intestinal canal, and  in the gall-bladder, and
have been particularly  described by Sir Everard Home.

   In regard to organization, the mucous membranes  are of a
soft, spongy consistence; easily yield to mechanical violence;
and  depend for their strength upon the surrounding cellular coat.
They are not of a uniform thickness; for example, they are much
thinner in the urinary and genital apparatus, than in the alimen-
tary canal; they ajso present some varieties of consistence. They
  * They are not  to be confounded with the follicles, but are a miniature repre.
eentation of what is called tripe, in culinary language. 
52                  ORGANS OF DIGESTION.

yield very readily'to putrefaction, and are quickly reduced to a
pulpy state by the action of the mineral acids.  Caustics of all
kinds act more promptly on them than on the skin, owing to the
protection of the latter by a dry epidermis; Bichat states, that in
the practice of-the Hotel Dieu, this effect is frequently exempli-
fied, by the administration of lunar caustic among the common
people for the purpose of poisoning.  The nitric acid leaving the
silver, quickly applies itself to the mucous membrane of the sto-
mach, and disorganizing it, forms a whitish eschar, which, if life
be preserved long enough, is finally detached in a membranous
form.
  One of the remarkable properties of the mucous surfaces of the
stomach  and intestines is, that of coagulating milk.  According
to the experiments of Spallanzani, the gastric juice, in the living
state, assists in this change; but it is perfectly well known in do-
mestic affairs, that the dried stomach of a calf, where the juices
have been completely evaporated, is also productive of it.   The
observations of the same author led him to conclude,  that the
peritoneal and the muscular  tunics  of  the stomach are insuffi-
cient to produce this effect.
  The internal surface of all the mucous membranes is furnished
with small projecting points or spiculas, called papillas or villi.
They are particularly conspicuous and numerous, as mentioned,
on the  upper surface of the tongue and in the small intestine,
and bear an analogy of function and organization with the very
fine  papillas which  are  seen  invariably on the surface of the
cutis vera.  These papillas are invariably furnished with ner-
vous filaments, giving them a high degree of sensibility;  and
with an abundance of blood vessels.  The term papillae has been
more exclusively applied to the projections on the surface of the
tongue, from their greater size; they are there also more distinctly
covered with an epidermis, frequently called epithelium, or peri-
glottis.   The villi, from  their connexion with  the process of di-
gestion, have been emphatically denominated the roots of ani-
mals. According to M. Beclard,* who has examined them upon
a plan of his own contrivance well suited to accurate microsco-
pic observations, they are presented under a diversity of shapes.
Those of the pyloric half of the stomach, and of the duodenum
being broader than they are long, are composed of very small
  * Anat. Gen. p. 253. These notions are not, however, in unison with my own,
as just stated.  Sect. III. 
GENERAL ANATOMY OF THE MUCOUS MEMBRANES.        53
 thin laminas, having a tufted arrangement.  Those of the jeju-
 num are long and narrow, having more the form commonly as-
 signed to them, while in the lower part of the ileum and in the
 colon they again become  laminated.
   It should be observed that notwithstanding the assertion of
 Lewenhoeck, Hewson, Hunter, and others, the fact is still called
 in question, by two of the  most distinguished anatomists of the
 present time, MM. Beclard and J. F. Meckel, whether the orifices
 of the lacteals are, under any circumstances, visible on the sur-
 face of the villi.  Admitting that they do not open as stated, the
 power of interstitial absorption  in  the  mucous membrane will
 still account for the chyle finally getting into the lacteals, as well
 as for fluids passing into the circulation  from the stomach, when
 its continuity with the intestinal canal has been interrupted.*
   The Epidermis or Epithelium of mucous membranes is very
 distinct at their external orifices, but becomes less and less ap-
 parent towards the interior of the body, until it finally cannot be
 distinguished; and anatomists generally consider that it is entirely
 deficient, notwithstanding the assertion of Haller to the contrary.
 It is a matter of common observation, that when  the interior of
 mucous membranes is exposed by an eversion for  a long time, to.
 the action of the atmosphere; they take on more of the structure
 of skin, and become evidently covered with a cuticle which pro-
 tects them  and diminishes their secretion.  This  is exemplified
 in eversion of the  vagina from prolapsed uterus,in elongated and
 tumid labia interna, and in other ways: restore the parts to their
 natural situation, and they are  brought back to.  their original
 structure. In the partial prolapse of the mucous membrane of the
 rectum, from piles, corresponding circumstances occur.  From
 this we infer, that the full development of cuticle  depends very
 much upon  the degree of  exposure which any surface of the
 body has to  undergo.  The reverse also  takes place: shut up or
close any surface of the skin so  that it is put in the condition of
an interior  cavity, and it immediately begins to  assimilate it-
self to a mucous membrane.  This is proved by the tendency in
young children to a detachment of the cuticle, or excoriation of
  * Should the suggestion of the absorbing powers of the gastroenteric follicles
wh.ch I have proposed in Section third, be correct, it will dispose of the difficul-
ties and opposing opinions alluded to in this paragraph.
                             6* 
54
ORGANS OF DIGESTION.
the opposed surfaces of the deep wrinkles about their thighs and
in their perineum; a tendency obviated by the practice of nurses
of covering  these surfaces with powdered starch.   It  is also
manifested frequently in the dressing  of wounds with sticking
plaster, where an incautious approximation  of  the contiguous
surfaces of the skin, not only is followed by excoriation, but even
by ulceration; a fact, the importance of which was formerly set
in proper relief by Dr. Physick in his  surgical lectures, and of
which I have seen an example in  a case of extirpated  female
mamma.  The slate of this question is, in fine, such that  I think
we may safely admit the existence of  a very thin epidermis on
the alimentary canal, but  so  pulpy  that  it cannot be  distin-
guished except by the  process alluded  to in Section third of this
Chapter.

  The mucous membranes vary in colour from a very light pink
to a deep  red, which  is owing to the  blood  that circulates  in
them.  In cases of suffocation, they become almost brown from
the congestion of blood in them, while in fainting they turn white
from the desertion of  the latter.   The vessels after having  pe-
netrated the thickness of the membrane, ramify with extreme
minuteness on its surface.   The veins  in an injection invariably
predominate over the arteries  by their greater size and  disten-
sibility.   In  consequence of their superficial situation, the ves-
sles being unsupported on one side, are exposed to rupture from
slight concussions; in this way hemorrhage is produced in  the
lungs from coughing, and bleeding at the nose from blows upon
the head.
  Exhalent orifices exist in great  numbers in the mucous mem-
branes:  this is especially the case in the lungs, where the pul-
monary perspiration, as it is called, is  very obvious to common
observation. Elsewhere, this discharge is so much blended with
the mucus of the part, that it is difficult to appreciate its quantity.
From the superficial situation  of  the  blood vessels, it is clear
that the exhalent orifices or pores, have but a short course to
run.   This is considered by Bichat as a satisfactory reason for
the tendency of  the blood to escape through them, or  to ooze
out where there  is no rupture.
  Absorbents exist also in great numbers, as proved by  the ab-
sorption of chyle, of  watery drinks from  the intestinal canal,
and by the inhalation  of the vapour of spirits of turpentine into 
OENERAL ANATOMY OF THE MUCOUS MEMERANES.       55
the lungs, rapidly communicating the particular smell of this
article to the urine.  There are, moreover, cases  recorded of
obstructed urethra, where .the  urine  has been almost entirely
absorbed by the mucous coat of the bladder.
  In regard to  nerves, the mucous membranes  are well  fur-
nished with them.  Bichat has  remarked that wherever these
membranes are situated near the surface of the body and enjoy
common sensibility, they are almost wholly furnished from the
central portions of the nervous  system, as the brain and spinal
marrow: this  is exemplified in  the conjunctiva, the pituitary
membrane, the  palate, the glans penis, &c.   On  the contrary,
the sympathetic nerve furnishes the intestines, the bladder, and
the excretory tubes generally.
   Mucous Glands, as they are called, exist throughout the sys-
tem of mucous membranes, being situated either under them or
in their thicknesses.  From them is derived  the  mucilaginous
fluid  which lubricates so abundantly their interior surfaces, so
as to  facilitate  the passage of  extraneous  bodies,  and, at the
same  time, to protect the membrane from mechanical violence.
These glands are of various sizes, from that of the tonsils and
the muciparous glands on the lips, cheeks, and root of the tongue,
to the almost imperceptible cryptas of the bladder and  urethra.
Their shape is either lenticular, rounded, or that of a pouch.
The  two former have their parietes of a sensible  thickness, but
the last are too thin to be distinguished from the mucous mem-
brane itself.  For the most part, the  excretory  duct  of these
glands is short  and patulous, so  as to lead directly into  the sub-
stance of the gland.  This is remarkably the case with the ton-
sils, which consist in a congeries of these follicles; and  with the
glands on the root of the tongue.  In some animals they are so
numerous as to form  almost a distinct  lamina to the intestines;
after the manner of the human  subject, on  the palate and pa-
rietes of the mouth.
  The Mucosity discharged from these glands  is  one of the
principles of animals, and, as  is well  known, exists also to a
great extent in some  vegetables.  When  perfectly pure and
fluid,  it is white, transparent, inodorous, and insipid.  It is  in-
soluble  in alcohol, but soluble  in acids.  Water forms more
than  nine-tenths of it, the remainder is mucus, properly speak-
ing, blended with some neutral  salts of soda and  potash. 
56                 ORGANS OF DIGESTION.
  The mucous membranes are exposed to a multitude of mor-
bid alterations, such as polypus, scirrhus, cancer, phlegmor-
rhagias or serous fluxes, blennorrhagias or  mucous fluxes, in-
flammation in all its forms, gangrene, ulcerations, and conges-
tions.
                   CHAPTER  IV.

        OF THE ASSISTANT CHYLOPOETIC VISCERA.

                  SECT. I.--OF THE LIVER.

  The Liver (Hepar, Jecur) secretes the Bile, and is the largest
glandular body in the human frame.  It, as mentioned, occupies
the whole of the right hypochondriac region, the upper half of
the epigastric, and, as it becomes thinner in going towards the
left side, it occupies a small space in the right superior part of
the left  hypochondriac region.  Its whole superior face is in
contact  with the diaphragm;  on the left it  is bounded by the
spleen, and below by the stomach and  the  transverse colon;
behind it, are the vertebral column and the ascending cava.
  The shape of the liver is like one half of an ovoidal body cut
into two in the direction of its long diajmeter, and having the
thick end turned to the right side.  It is about ten inches in
length  by six dr  seven wide, and weighs  from four  to five
pounds in  the adult.  Its colour is a reddish brown, generally;
though,  on  its under surface and about its edges, broad, blue or
black patches are constantly met with, which do not indicate
any morbid derangement.
  Its upper surface is of a uniform convexity, rather more pro-
minent at the right posterior part than elsewhere; adjusts itself
accurately  into the concavity made by the under surface of the
diaphragm; and is unequally divided from before backwards by
the suspensory ligament.  The  anterior margin is thin, and is
notched where the suspensory ligament begins; the posterior
margin  is much thicker, and has near its middle a broad de- 
THE LIVER.
57
 pression, to fit it to the projection of the vertebral column.  The
 ascending vena cava forms a superficial sulcus upon this mar-
 gin, and frequently there is a complete canal through the sub-
 stance of the liver for transmitting it.   The right extremity is
 very thick, and almost fills the hypochondriac  region of that
 side, while the  left extremity is reduced to a thin* tapering, and
 flexible edge.
   The under surface of the liver is much more irregular than
 the upper; it is traversed in an antero posterior  direction, in a
 line corresponding with the attachment above of the suspensory
 ligament, by the umbilical  fissure, (Sulcus Umbilicalis)  which
 extends from the notch in the front edge to the depression  be-
-hind, and obtains its name from having accommodated  in  the
 foetal state, the umbilical vein, now converted into a round liga-
 mentous cord.   In the posterior part of this fissure is likewise to
 be seen, in the  same condition, what remains of the ductus  ve-
 nosus.  The anterior portion of the umbilical fissure is not  un-
 frequently converted into a complete canal, by a portion of he-
 patic substance crossing it like a small  bridge.  The transverse
 fissure (Sulcus  Transversus, Intermedins)  is situated in the mid-
 dle of the under surface of the liver, and extends along a third
 or fourth of the long diameter of the  latter.  It begins some-
 what to the left of the umbilical fissure, and crossing it at right
 angles,  proceeds towards the right extremity.  It  contains  the
 vena portarum, the  hepatic artery, and the hepatic duct;  all
 of which are bound to each other by a close cellular substance.
   The suspensory ligament above, and the umbilical fissure be-
 low, give occasion to divide  the liver into Lobes; Right  and
 Left; of which  the right is by much the largest, and accommo-
 dates almost entirely the transverse fissure, having also on its
 under surface  some subordinate elevations, to wit,  the Lobu-
 lus Spigelii and the  Lobulus Quartus, together with the Gall-
 Bladder.
   The Lobulus Spigelii  is placed between the  transverse  fis-
 sure and the posterior margin of the liver, to the  right of the
 posterior end of the  umbilical fissure.  Its shape is somewhat
 prismatic, bifurcating in front; one of  the elongations is a pa-
 pilla overhanging the transverse fissure, and is, therefore, con-
sidered as one  side of the  gateway (porta) opened for the ve-
na portarum; the other elongation is a small ridge, sometimes 
58                 ' ORGANS OF DIGESTION.
called Lobulus Caudatus, and is lost gradually on the under
surface of the great lobe, by inclining to the right.
  The Lobulus Q,uartus, or Anonymus,  is not by any means so
elevated as the last, but having a flattened surface, is placed in
front of the transvere fissure,-between the fore end of the um-
bilical fissure  and  the  gall-bladder; its posterior extremity is
the second porta of the Liver, and is  just opposite to that fur-
nished by the Lobulus Spigelii."
  The liver, from  being completely enveloped in peritoneum,
has a smooth glossy  appearance. The reflections of this mem-
brane, from  it  to the parietes of the abdomen, form the liga-
ments, as  they are called, which consist each of two laminas.
The Falciform Ligament, or  Suspensory, containing in its an-
terior margin the  remains of the umbilical  vein, now called
Ligamentum  Teres,  begins  at the  umbilicus, extends from it
along the linea alba and the  middle line of the diaphragm,
and, as mentioned, is reflected to the upper surface of the liver,
from  the  anterior  to the posterior  margin.  The Right  Late-
ral Ligament  is situated behind, and departs from  the  back
part of the  diaphragm to the posterior  margin of the  right
lobe.  The Left Lateral Ligament also  goes from the  back
part of the  diaphragm, and is  attached along the posterior
margin of the  left lobe.  Where the suspensory ligament in-
clines on each side into the lateral, it passes with so much ob-
liquity as  to leave  some portion of the posterior  margin of the
liver uncovered by peritoneum;  the latter, where it describes
the periphery of this space, has  been rather  unnecessarily de-
signated as the Coronary Ligament.
  In addition to the peritoneal coat, the  liver  has another, con-
necting  it with the peritoneum,  and seeming to  be only con-
densed cellular substance, which also penetrates into the sub-
stance of  the gland,  and holds its  constituent parts together.
It  is particularly well seen within  the  circle of the coronary
ligament.

               Of the Organization of the Liver.

  The glandular substance of the Liver is fragile and easily
lacerated; and consists of a congeries of spherical or polyhe-
drical grains, called acini from their resemblance to small ber- 
THE LIVER.
59
ries; they are best seen on tearing the organ, are united in mass
by the elongations of the cellular coat, and  traversed  by the
trunks of the blood vessels.  Each of these  granulations  is
about the size of a millet seed,  and is a representative of the
entire gland, as its structure is complete in itself; being  formed
by the terminations of the blood vessels, and  by the origin of a
branch of the hepatic duct, called the porus biliarius.   When
examined with a  microscope, it is said that these acini are ob-
served to be composed of a yellow and of a brown-looking sub-
stance; it has not, however, occurred to me  to see the distinc-
tion in a very satisfactory way, though it is  recognised by an-
atomists of high authority.*

   The Liver is made extremely vascular  by the ramifications
of three kinds of blood vessels, the Vena Portarum, the Hepatic
Artery,  and the  Hepatic Veins.  The two first convey the
blood to it, and the  third removes it again, into the general cir-
culation, by emptying into the ascending vena cava.   There
are also  the commencing radicles of the hepatic duct, lympha-
 tic vessels, and the nerves.
   The Vena Portarum having arisen from the junction of all
 the veins of the stomach, intestines,  pancreas and spleen,  is
 about three inches.in length when it reaches  the transverse fis-
 sure, by going over the duodenum and under the pancreas.   It
 immediately divides into two branches, called collectively the
 Sinus Venas Portarum, which is  at right angles with the trunk
 of the vein; the right branch being the shortest and largest, is
 distributed  by radiating trunks  to the right  lobe of the liver;
 the left branch is distributed, after the same  manner, to the left
 lobe, to  the lobulus spigelii, and to the lobulus  quartus.   Some
 of its branches anastomose with the hepatic veins, which ac-
 counts for the ease with which an injection  will pass from one
 to the other.  Other branches of a smaller description  anasto-
 mose with the biliary ducts, but with less freedom than in the
 preceding case; and lastly, the most delicate ramifications are
 spent upon the cortical  or yellow matter of the acini,  without
 penetrating to the  brown.t
* Bichat, Meckel, &c.         + Mappes, J. F. Meckel, loc. cit. 
60
ORGANS OF DIGESTION.
   The  Hepatic Artery is  a branch of the coeliac, and in ap-
 proaching the transverse  fissure divides into  three  or more
 branches, that penetrate the substance of the  liver, between the
 sinus venas portarum and the ducts as they come out; one branch
 goes to the  right lobe, another  to the left, and a third to the
 lobulus spigelii.  There is some variety in regard to  the pre-
 cise mode of distribution,  and their  division into subordinate
 ramifications frequently occurs before they get fairly into the
 substance of the liver.  When there, they  seem to be intended
 for the nourishment of this  organ, according to the observations
 of several able anatomists; and follow the  ramifications of the
 vena portarum and of the biliary ducts, forming upon them a
 very delicate and complicated tissue of anastomosing vessels;
 some of which, probably the vasa vasorum, communicate with
 the vena portarum.
   The Hepatic Veins arise in the acini from  the capillary ter-
 minations of the vena portarum and the hepatic artery.   Their
 branches are successively accumulated into three large  trunks,
 the collective area of which  vastly exceeds that of the  vessels
 bringing the blood to the   liver.  Two  of  these  trunks come
 from the right lobe and one  from the left, to  empty into the
 ascending cava, while it is still in  contact with the liver, im-
 mediately  below the  diaphragm;  just  below  the preceding
 trunks there are five  or  six, sometimes more, small  hepatic
 veins, coming from the posterior margin  of the  liver, and from
 the lobulus spigelii.   The hepatic veins are destitute of  valves,
 and remarkable for the thinness  of their parietes.   An injec-
 tion passes readily from them into the other systems of vessels.
 They may be recognised  by their insulated course,  by their
 consisting in trunks which  converge from the periphery of the
 liver to  the vena cava, while all the other vessels diverge from
 the transverse fissure to the periphery, and consequently cross
 the course of the hepatic veins.
  The commencing  radicles  or  ramifications  of the  hepatic
 duct, take their origin in the  acini; and, as  is  said, upon the
 boundary between the two  kinds of matter,  avoiding the brown
and passing through the cortical.*  The  larger  branches con-
 verge into their respective trunks  successive!v or in pairs:
* J. F. Meckel, loc. cit. 
THE LIVER.
61
while the primordial, or most minute ones, converge several of
them to the same point, giving a penicillous appearance.  These
several tubes constitute the Biliary Pores (Pori Biliarii) and are
always in the same group with the branches of the Vena Por-
tarum  and hepatic  artery.  It is asserted  that a fine injection
passes more readily from  them  into the lymphatics than into
any  other order of vessels; which may account for the prompti-
tude of jaundice upon an obstruction of the hepatic duct.
   At the bottom of  the transverse fissure of the liver is to be
found  a dense cellular fibrous tissue, which  invests the vena
portarum, the hepatic artery, and the biliary ducts; and, as they
all keep together in their ramifications, this tissue follows them
throughout the substance of the liver, and thereby forms sheaths
for them.  It may  be considered as  continuous with the pro-
cesses sent in from the cellular coat;  and, contrary to the opi-
nion of Glisson, whose  capsule it has  been called,  it is  devoid
of muscular structure.*


                      Of the Gall Bladder.

   The Gall Bladder (Cistis Fellea) is a reservoir, for the  bile se-
creted by the liver.   It is fixed on the under surface of the great
lobe, to the right of the*umbilical fissure, and  removed from the
latter  by the  lobulus quartus.f   It is  an  oblong pyriform sac,
having its anterior extremity or fundus projecting somewhat be-
yond  the anterior  margin of the liver, while  the posterior end
reaches  to the transverse fissure.   Its long  diameter inclines
slightly to the right side, so that  it is not  precisely in an antc-
ro-postcrior line.   It varies in its shape in different subjects, be-
ing  much more spheroidal in some than in others.   Its fundus
is rounded and obtuse, while the posterior end is gradually re-
duced to a narrow neck, which is bent up on itself, so as to re-
tard the flow of a  fluid through it.  Its upper surface is  in con-
tact with the substance of the liver, and is received into a broad

   *  An elaborate work on the minute anatomy of the liver has lately appeared,
from the English press, by Francis Kiernan, Esq. R. C. Surgeons, London, 1833,
in which there are some peculiar notions of structure. It is highly creditable to
the zeal of the author, and well worthy of perusal.
   \  I have seen an instance where it was to the left of the umbilical fissure, on
the small lobe.  The latter was much longer than common.  Dec. 1830.
   Vol. II.—7 
62
ORGANS OF DIGESTION.
shallow fossa, while the lower surface  is projecting,  and by
coming in contact with the transverse colon, tinges it with bile,
by transudation after death.

  The Gall Bladder has three coats, a peritoneal, a cellular, and
a mucous one.
  The Peritoneal Coat is not complete, but only covers that part
of the sac not received into the fossa on the under surface of the
liver; it is, therefore, a continuation of the peritoneal coat of the
latter; sometimes, however, the gall  bladder is so  loosely at-
tached to the liver that it almost hangs off from it, in which case
the  peritoneal coat is nearly complete.
  The Second coat is condensed cellular membrane.  Through
it ramifies a great number of lymphatics, and blood vessels; be-
low, it attaches  the  peritoneal to  the mucous coat, and above,
the  latter to the liver.
  The Mucous Coat is always tinged of a deep green or yellow,
by the bile  which it contains percolating after death; for  it is
said to be, before that, of a light colour.   This  coat is  thrown
into  irregular tortuous folds or wrinkles of extreme delicacy, in
the  intervals of which are many round or  polyhedrous cells,
causing it to look, when floated in water, like a fine honey comb:
such as are about the fundus of the sac are superficial, and not
so distinct; but those near its middle and about the neck, are  a
line or a line and a half deep.  In the neck or apex, and in the
beginning of the cystic duct, are from three to seven, sometimes
twelve, semilunar duplicatures of the internal membrane, which
also retard the flux and afflux of any fluid, though they do not
afford so much resistance to the ingress as to the egress of it.
These duplicatures are sometimes arranged into a spiral valve,
projecting from the inside of the duct, and forming two  or three
turns.*  Very small  mucous follicles exist over the internal face
of this membrane, the discharge of which fills the gall bladder
when the secretion of bile has been interrupted by diseased ac-
tion, as in yellow fever, rjr by scirrhus of the liver.
  The artery of the gall bladder  is  a branch of the  hepatic.

  *  Discovered latterly by M. Amussat of  Paris.  M. Amussat has also detected
rouscular fibres in the gall bladder and biliary ducts, in which we see an analogy
with other hollow viscera.—Am. Med. Jour. Vol. ii. p. 193. 
THE LIVER.
63
Its veins empty into the vena portarum.  Its nerves come from
the sympathetic, and  its lymphatics join those of the liver.


                    Of the Biliary Ducts.

  A succession of very fine branches  having arisen from  the
acini of the liver, these branches are united into three or four
trunks by the time they reach the transverse  fissure.  These
trunks then coalesce into a single Duct, the Hepatic, of eighteen
or twenty lines in length, and about the diameter of a writing-
quill.  The Hepatic  Duct  is  then  joined at a very acute angle
with the duct from the gall-bladder, which is  somewhat shorter
and smaller;  the union of the  two forms the Common Duct,
(Ductus Communis  Choledochus.)   The latter is  larger than
either of the others  singly, and is three  or  three and  a half
inches long; it descends behind the right extremity of the pan-
creas  through its substance, passes for an inch, obliquely, be-
tween the coats of the duodenum, becoming at the same time
diminished  in diameter; and,  finally, ends  by an  orifice  still
more  contracted, on the internal face  of this gut, on its second
turn, and about three or four inches from the stomach.  The
 orifice is marked by a small  surrounding tubercle somewhat
 obscured by the valvulas conniventes.
   The Hepatic, the Cystic, and the Common  Duct are situated,
 as mentioned, along the right margin of the lesser omentum, and
 have the vena portarum and the hepatic artery to their left.
   The bile ducts  are  formed  by two coats;  the external is a
 fibrous, lamellated, and very  extensible  membrane, while the
 internal is mucous, having the same structure with that of the
 gall bladder, of which it is in direct continuation.  In the Cystic
 Duct, and at the lower part  of  the Common  Duct,  are  several
 longitudinal folds.   The Common  Duct sometimes receives,
 just before  it empties into the duodenum, the Pancreatic Duct.


                         Of the Bile.

   This secretion from the live*, is of a deep  yellow, sometimes
 green colour: when reeent,  it is thin and fluid; but after it has 
64
ORGANS OF DIGESTION.
been conveyed to the gall bladder, and  permitted  to  remain
there for some time, it  becomes as thick as molasses, and in-
creases  also in the intensity of its colour and  in  bitterness.
Some anatomists  have believed that there was a more direct
communication between the liver and the gall bladder than that
through the hepatic and the cystic duct; but repeated and close
observations have proved  the opinion  to  be  erroneous, or, at
least destitute  of  proper proof: it is, therefore, clear, that  the
difference between the hepatic and the cystic bile, depends upon
the watery particles being removed from the latter  by  the  ab-
sorbing  power of the internal coat of the  gall bladder.
  According to  Berzelius, the chemical analysis of bile fur-
nishes about eighty  parts of water, eight  of a particular  sub-
stance which assumes a  resinous condition on the  application
of an acid: three of mucus; and nine of saline matters; of which
soda is a principal constituent.
                  SECT. II.—OF THE SPLEEN.

  The Spleen (Lien, Splen) is situated deeply in the posterior
part of the left hypochondriac region, and is bounded above by
the diaphragm, below by the colon, and on  the right by the
great end of the stomach, and by the pancreas.  It is not ascer-
tained that it secretes any thing.
  Its colour varies from a deep blue to a dark brown.  In shape
it resembles  the longitudinal section of an oval, being flat or
very slightly concave on the surface next to  the stomach, and
convex on  that contiguous to the diaphragm.   Occasionally its
margins are notched, but this is not invariably the case.   Its
flat surface is slightly  depressed longitudinally in  the centre
into an imperfect fissure, where the blood vessels enter it by
six or eight foramina.
  Several spleens  sometimes exist in  the same individual, in
which case the supernumerary ones are not larger than  nut-
megs.  The common size of this organ is about four and a half
inches long, by two and a half or three wide, in which case
it has a solid firm feel;   but it very often exceeds these dimen-
sions ;  its transition and varieties of magnitude are so frequent,
that no settled rule can be established. In its inordinate enlarge- 
THE  SPLEEN.
65
 ments I have seen it only a little smaller than the liver; its tex-
 ture in this case is soft and easily lacerated. -
   It is fixed  in its place by three lines of reflection or processes
 of peritoneum, called ligaments,  whose names  indicate  their
 places of attachment.  They are  the Gastro-Splenic Ligament
 or Omentum, which passes from the stomach to the spleen, and
 in which are the vasa  brevia of the  stomach; the Splenico-
 Phrenic  Ligament,  which goes  from the spleen to  the dia-
 phragm ; and the Splenico-Colic Ligament, which passes  from
 the spleen  to the colon.   These reflections, by being continued
 over the spleen, give it  a complete peritoneal coat, which is
 raised up with more difficulty than the corresponding membrane
 of any other  viscus of the abdomen, and is commonly thrown
 into very small inequalities or wrinkles.
   The internal or proper coat of the spleen is a grayish, com-
 pact, extensible, and elastic membrane, the use of which is evi-
 dently to sustain the natural shape of the organ, and to support
 its parenchymatous structure.   It sends in processes to  accom-
 pany the blood vessels, and from its internal face there proceeds
 a  multitude-of lamellae and of fibres, which traverse its cavity
 in every direction, and reduce it  into a cellular condition, not
 unlike the spongy structure of bones.
   The spleen, in proportion to its size, is furnished to a remark-
 able degree with  blood.   The largest branch of the  cceliac ar-
 tery runs to it along the superior margin of the.pancreas, form-
 ing numerous serpentine flexures, and distinguished for its thick-
 ness;  it divides into  several  trunks for penetrating  into the
 spleen, and enters by the foramina in  the fissure.  The veins
 come out by  a number of trunks equal  to what the artery is di-
 vided into; they assemble then into a  single trunk, which at-
 tends the artery along the pancreas, and  is remarkable for the
 tenuity and extensibility of its  coats.  The splenic vein is  des-
 titute of valves, and empties into the vena portarum. The spleen
 has also  lymphatic  vessels;  and is furnished with nerves from
 the solar plexus.
   Of the Intimate Structure of the Spleen.—The Splenic arterv
having penetrated into this organ, is divided and subdivided into
a radiating succession of very fine branches, which,  according
to  the injections of Ruysch, do not  anastomose with each other;
in  consequence of which, one part is sometimes finely injected
                            7* 
66
ORGANS OF DIGESTION.
and not another, of which, in my own observations, I have had
an example.  The veins, on the contrary, do  anastomose, not
only as regards the collateral branches of the same primitive
trunk, but also by the collateral  branches of  different trunks.
These  anastomoses are not large.   The arteries terminate free-
ly in the veins, as mav be proved by fine injections, and by the
microscope.
   The mass of the spleen, upon superficial examination,  seems
to consist in a dark brown pulp, which is contained in the cells
dividing the cavity of the internal coat, and may be easily de-
monstrated by tearing the  spleen, and scraping it with a knife
handle.  MM. Assolont and Meckel believe, that blood, besides
being in the arteries and veins, is placed in a state of particular
combination and of intimate union with the other organic ele-
ments  of this viscus, and with a large quantity  of albumen ; and
that this combination of the blood forms the  dark brown pulp
alluded to.  The great quantity of albumen in the pulp, is rea-
dily proved by the hard coagulum which it forms, when steeped
in alcohol.  But a question has arisen whether the pulp be ex-
travasated in the cells which contain it, or whether it be still re-
tained in the extremities of the blood vessels.   Superficial exa-
mination is in favour of the first, but M. Marjolin denies it on
the following grounds;, that injections, cautiously made, pass
immediately from  the  arteries into  the  veins; and that the
spleen, when successfully injected and frozen, does not exhibit
ice in  the interstices of its vessels, while  their capillary ramifi-
cations  distended by  the  injected  fluid,  are distinctly seen.
From  these he concludes that the glandular structure  of the
spleen is formed essentially of arterial and venous capillary ves-
sels with very delicate and extensible coats; that they commu-
nicate with one another without the intermedium  of any cell;
and that the extreme tenuity of these  vessels, and their  exten-
sibility in every direction, are sufficient to explain the augmen-
tation  of volume of the spleen, under  certain circumstances, as
well as the promptitude of its diminution under  others.
   In addition to  this pulp, many observers  have  met  in the
spleen with an abundance of  rounded corpuscles, varying  in
size from an almost  imperceptible magnitude  to a line or more
in diameter.*   They are of a gelatinous consistence, soft, gray-
* Malpighi, Kuysch,. Hewson, Uome, Dupuytren, Meckel, &c. 
THE SPLEEN.
67
ish, and  semi-transparent, and either cluster  together, or are
widely separated.   By Malpighi, they were considered glan-
dular,  and by  Ruysch,*  as  convoluted vessels.   Professor
Soemmering, from  the  following  paragraph, seems to join in
the opinion of the  latter:  " Qui nonnunquam  occurrunt, acini
vel glomeruli, microscopii  ope accuratissime exjplorati nihil
sunt, nisi vasorum  fasciculi, vel teretes  penicilli  aut cirri vas-
culosis   According to the observations of Sir Everard Home,
they swell considerably after an animal has finished drinking.
   The spleen, from  having  no excretory duct, and  conse-
quently, from  our inability  to ascertain whether it  secretes,
 has its nature and  uses shrouded in mystery.   No single the-
 ory concerning it has  ever  been generally adopted, for  specu-
lations have multiplied in proportion to the  obscurity  of the
 subject.  The idea, however, on the use of this body, which to
 me is  most reasonable, is, that it acts a subsidiary part to the
 liver.   It would seem, indeed, as  a general rule in regard to
 glandular structures and such other highly vascular organs of
 the body as have an intermittent function, that the blood which
 is sent to them during their state of activity, should be  passed
 off through a different channel, while they are in a state of re-
 pose.   This does  a double service, it prevents superfluous se-
 cretions, and it also  keeps up the vascular equilibrium of the
 body, as there must be always in readiness a  quantity of blood
 sufficient for the supply of any secretion which  may  be want-
 ed for the time.
    This proposition will derive some additional illustrations from
  the foetal state.   The  kidneys being then inactive the capsulae
 renales take off their blood, and  thereby prevent what would
 otherwise be a very inconvenient secretion of urine; again, the
 lungs being also then inactive, the circulation through them  is
 proportionately reduced, and the  superabundant blood is con-
 ducted through  the  thymus  gland.  But as  the full  functions
  of the lungs and of the kidneys are established upon birth, and
  continue uninterrupted during life, their supplementary organs,
  the thymus gland, and  the  capsulae renales, are not wanted,
  and they wither away after  the  early period of infantile exis-
  tence is passed.
    In  regard to the liver, its functions also suspended during the
* Epis Anat. IV. 
68                  ORGANS OF DIGESTION.
foetal state, are of an intermittent kind throughout life, the spleen
may, therefore, be  considered  a vicarious organ for  it during
the whole period of existence, receiving its blood during the*
continuation of uterine life, and, in the intermission of action,
during common  life.  The spleen is, therefore, an organ useful
to the  foetal  and to the perfect state, and we, consequently,
never see it in the collapsed and dwindled condition of the thy-
mus gland, and renal capsule.
  The same  reasoning which applies  to  the spleen,  will also
apply to  the Thyroid Gland:  the latter may be considered as
executing for the salivary glands during foetal and perfect ex-
istence, what the spleen does for the liver.  For it  is ascer-
tained, that the salivary glands are inactive during foetal exis-
tence, have only an  intermittent action  during perfect life, and,
therefore, probably   stand in need  of  a supplementary organ
during their periods of inactivity.
                 SEC III.--OF THE PANCREAS.

  The Pancreas (Pancreas) secretes saliva, and is the largest
of the salivary glands.   It is  fixed in  the  lower back part of
the epigastric region; and extends horizontally across the spine,
being separated from it  by the lesser muscle of the diaphragm.
It is  connected to the spleen on the left;  at  its  right extremity
is surrounded  by the curvature of the duodenum; is bounded
in front by the stomach, which conceals it; and is placed be-
tween two laminas of the mesocolon.
  The pancreas is  about six  or seven inches long, two wide,
and  flattened before and behind.  Its  figure would  be  repre-
sented by a parallelogram, were it not that its right extremity
is enlarged considerably into  a head or tuber, to which Wins-
low  gave the  name of the Lesser Pancreas.   The anterior
face  of this organ is turned obliquely upwards, and is covered
by the superior lamina of the mesocolon.   The  posterior  face
looks obliquely downwards, and is  in  contact with the aorta,
the vena cava ascendens, the superior mesenteric  vessels, and
several nerves: along the superior margin of this face exists
a long superficial fossa, occupied  by the  splenic  artery and
vein. 
THE PANCREAS.
69
  With the exception of the loose covering given by the meso-
colon,  the pancreas has no peritoneal coat;  neither has  it an
appropriate tunic, unless we consider as such the lamina of con-
densed cellular membrane which envelops it, and sends in pro-
cesses between its lobules, as in the case of the salivary glands in
the neck.

   Of the Minute Structure of the Pancreas.—•This body, like the
other glands, which discharge saliva, is of a light gray or pink
colour.   It consists in lobules of various forms and sizes, united
by an intermediate cellular tissue,and having their interstices oc-
cupied by numerous blood vessels.   These  lobules, by a  slight
maceration, may be separated and resolved  into small granulai
masses, constituting integral portions of the gland.
   The arteries of the pancreas  come principally from the sple-
nic, as it  cruises along  the superior  margin.   The veins empty
into the splenic, and thus, finally, into the vena portarum.   It is
furnished with nerves from the solar plexus, and has lymphatics.
   The excretory duct of this gland (Ductus Wirsungii) arises, by
very fine roots or tubes, from each of the small granular masses.
 These  tubes  coalesce into larger ones,  which run transversely
 from the periphery towards the centre  of the gland,  inclining
 slightly, at the same time, towards the right.   These secondary
 tubes finally discharge successively into a single one, which runs
 the whole length of the gland nearly in  its middle.   The single
 tube,  by these additions,  enlarges continually from left to right,
 being small where it  begins at the splenic extremity of the pan-
 creas, and about the size of a crow-quill at the duodenal.   At the
 latter  place, it is joined  by the duct of the lesser pancreas,  which
 is derived after  the same rule as itself.  The pancreatic duct, al-
 most immediately afterwards, empties into the ductus communis
 choledochus,  or runs  at the side of the latter, and makes  a  dis-
 tinct opening near it  into the duodenum, at the posterior part of
 the second curvature. 
w
*
♦ 
BOOK  V.
                OF THE URINARY ORGANS.

  The Urinary Organs, (Organa  Uropoietica) being  destined
to secrete and convey the urine out of the body, consist in the
Renal Capsules, the Kidneys, the Ureters, the Bladder and the
Urethra.

                     Of the Kidneys.

  The Kidneys (Penes) are two glandular bodies for the secre-
tion  of the urine, fixed one on either side of the spine.  They
are in the back part of the lumbar regions, have their internal
edges  inclining very slightly forwards, and extend  from the
upper margin of the eleventh dorsal to the lower margin of the
second lumbar vertebra: the right, however, is ten or twelve
lines lower than the left, owing to the thick posterior margin
of the right lobe of the liver, which presses it downwards.   The
kidneys are covered in front by the peritoneum and the lumbar
portions of  the large intestine, but in  such a manner  as to be
separated from them, in  corpulent subjects, by a  surrounding
layer of fat;  behind, they repose upon  the  lower part of the
great muscle of  the diaphragm, upon the quadrati lumborum,
and  upon the upper end of the psoas magni muscles.
  The kidney is a hard solid body, of a brown colour; in shape
it is a compressed ovoid, excavated on the margin  which it
presents to the spine, and bears a very strong resemblance to
the common  kidney bean.   Its flat  surfaces present  forwards 
72
URINARY ORGANS.
 and backwards, and the broad end of the  ovoid is above.  Its
 periphery is smooth, so that one does not infer from an external
 examination, the lobules or internal divisions.  The excavation
 of the kidney, called its fissure, (hilum renale) occupies about
 one third of its long diameter, is bevelled in front, and leads to
 the very interior of the gland; conducting its blood vessels and
 excretory duct, which have to pass through a quantity of cellular
 and adipose matter.  The kidneys are generally of equal size,
 being about four inches long,and two wide; and each one weighs
 three or four  ounces.  They  have no ligaments  for  keeping
 them in position, but depend for the latter  upon the adjacent
 cellular adhesions and blood vessels.
   The kidney  being  destitute of a  peritoneal  coat, has a well
 marked capsule which envelops  it entirely and  penetrates into
 its fissure for some depth, where it is perforated with foramina
 for transmitting the blood vessels and the ureter.   This capsule
 is white, semi-transparent, fibrous, strong, and elastic: it adheres
 to the surface  of the kidney by delicate cellular and  vascular
 filaments, which are so weak that they permit  it to be stripped
 off without difficulty, and when so  removed, some indications
 of the lobulated condition of the organ are seen.

   Of the Minute  Structure of the Kidney.—When the kidney is
 cut open  longitudinally,  it obviously consists  of two  kinds of
 substance, differing in their situations, colour, consistence, and
 texture.   The  one making the periphery of the gland is called
 from  its position Cortical,  (Substantia Corticalis,  Glandulosa,)
 while the  other,  being  more internal, is  designated as  the
 Medullary or  Tubular, (Substantia  Medullaris; Tubulosa;  Fi-
 brosa.)

   The Cortical or Secretory Substance forms  the whole cir-
 cumference of  the  kidney, and, on  an average, is about two
 lines in thickness; but it  is thicker at some points, as, from  its
 internal face,  processes  converge  towards the centre  of the
 gland, which separate the tubular part into as many distinct
 portions of a  conoidal shape.   It is composed principally of
 arteries and  veins ramifying, among small graniform cor-
puscles  that secrete  the  urine, and are  very  distinct when
viewed with a  microscope.  It tears with facility, thereby pre- 
THE KIDNEYS.
73
senting this granular appearance, and is of a dark or reddish
brown colour, varying  considerably, however, according  to
the cause of death.
  The granular corpuscles which form the mass of the cortical
or secretory substance, are, individually, imperfectly visible to
the naked eye, and appear like rounded points.
  The celebrated Ruysch, who was distinguished for the  suc-
cess of his injections, and for the  acuteness of his vision, de-
clared that they consisted wholly in the very fine extremities
of arteries and veins having  a penicillous arrangement; while
Malpighi and Schumlansky viewed them  as purses  or  small
sacs of  a glandular character, specifically  suited to secrete
urine,  and upon  whose  parietes the blood  vessels  ramified.
From these granuli or acini the incipient extremities of the tu-
buli uriniferi take their rise.
   The Tubular or Conoidal portion, consists  in from twelve to
eighteen  conoidal fasciculi (Pyramides  Malpighiance) present-
ing  their rounded bases  towards the cortical matter, and en-
closed in it, while their apices converge  to the central cavity of
the  kidney, the  surface  of which  they form.  The bodies of
these pyramids, as just  mentioned,  are  separated by processes
of the cortical matter; but their apices are  free, and project
from the internal surface of  the kidney so as  to resemble  as
many small nipples, whence  they are called Papillas  Renales.
Frequently two of the pyramids coalesce so as to form but one
papilla together;  in such case the latter generally preserves a
 duplicate appearance.  The papillas are arranged into three ver-
 tical rows, one before, one in the middle, and  another behind;
 those of the foremost row are turned backwards; those of the
 middle look inwards; and those behind look forwards.  Not un-
 frequently, there  is a small depression (foveola) on  the  very
summit  of the papilla.   The  tubular part is of a lighter colour
and harder than the cortical, but the difference in these respects
is not always manifest.
   The conoidal fasciculi may each be considered, along with its
 appertaining cortex, as a sort of distinct gland, or at least as a
lobe;  for upon them depends the lobulated appearance of the
kidneys of a fcetus, and of animals.  Each cone, when  analyzed,
is found to  consist in  a collection of  tubes (Ductus Uriniferi
Bellini)  converging from the  circumference of  the  kidnev to
   Vol.  II.—8 
74
URINARY ORGANS.
the apex of the papilla.  These tubes are more numerous near
the base, in  consequence of their  successive junction in  ap-
proaching the apex:*  their terminating orifices, on  the latter,
appear like small pores, from which the urine can be squeezed
in little  drops.
   In the early part of  the course of the ductus uriniferi, while
they are still in the cortical matter, they are wound up in a
very serpentine and tortuous manner, and are distinguished by
the name of Cortical Canals, (Ductus Ferrenii.])  They com-
monly go alone, winding their way in the cortical substance
until they reach its most interior face; they then become straight,
form the medullary substance,  and have the  name of the con-
duits or uriniferous ducts of  Bellini4

   Some of the calculations on this subject are not a little curious.
It was ascertained by  Ferrein that in each of the conoidal fas-
ciculi (Pyramides Malpighiand) there were, at least  seven hun-
dred subordinate cones  or pyramids, Pyramides  Ferrenii; and
as the number of conoid-al fasciculi is  generally about fifteen,
these pyramids would amount to ten thousand  five hundred.
Again,  each of the subordinate pyramids (Pyramides Ferrenii)
is composed of many hundred uriniferous tubes, and, by the ob-
servations of Eysenhardt,J each of these tubes consists of twenty
smaller ones.
   The  kidney receives from the aorta one or more branches,
called the renal or emulgent arteries, which  divide as they ap-
proach the fissure; and having got into the substance of the
gland are  distributed  by innumerable twigs to all parts of it.
Some terminate in veins, others in the substance of the organ,
and others,  again, in the excretory tubes.   The  veins equal in
number the arteries, and are somewhat larger.  When both, or
 even one, of these systems of blood vessels  is  injected  with
 wax and corroded, its branches are so abundant as to retain the
 form of the gland.  In  engaging in the fissure  of  the kidney,
 the arterial  ramifications are  in front, the veins  in  the middle,

   • Schumlansky, Dis. de  Struct. Tienum, Strasburg-, 1788.
   f A. Ferreinj sur la Structure des reins et du foie.  Mem.  de Paris, 1719.
   * L. Bellini, de Slructura Renum. Florence, 1662.
    § Dc  Struct, ltenum. Obs. Micros.  Berlin, 1818. 
THE KIDNEYS.
75
and the commencement of the ureter behind.*  The artery on
the right side is longer- than that on the left.  The reverse is
the case with the emulgent veins, as they empty into the vena
cava  ascendens.  This  arrangement  is owing to the relative
position of the aorta and the vena cava ascendens, as the first is
on the left side of the spine, and the last on the right side.
  The nerves come from the  solar plexus of the  sympathetic,
and adhering to the arteries cannot be traced very far through
the glandular structure.   The  quantity of lymphatics is consi-
derable.
  The arteries of the kidneys, in ramifying  minutely through
its structure, adopt the following arrangement.  They first of
all pass through the processes sent inwards from the cortical
matter between the Pyramids of Malpighi, or large cones, and,
having got fairly into the cortical matter, they divide into very
fine twigs, which form arcades around the bases of the pyramids
of Ferrein, and pass between them.t  These arcades have but
few anastomoses with each other, and their branches go almost
exclusively to the cortical substance, very few of them being
found on the tubular.   Their  branches radiate from the con-
vexities of the arches  so as to  surround the base of  each  cone,
and to penetrate to the  surface of  the kidney.  Some of  these
branches terminate  in  corresponding veins, and  others on the
granular corpuscles, or acini.   The connexion between the cor-
puscles and the  arteries, has been compared to  that between
grapes and the stems on which  they grow, so as to form a bunch.
The veins penetrate the substance of the kidney, and  have a
similar distribution; but they are much larger than the arteries,
and have free, large and numerous anastomoses.   A connexion
of the corpuscles with the veins is not quite evident, and, even
if it does exist, remains yet to be  proved ; at least, in the opinion
of some anatomists: the fact, however, is well established, that
fine injections will  readily pass  from the veins into the  tubuli
uriniferi.

   The kidneys are subject to  a false position: in  one instance,
I found in a young female subject one of the kidneys in  the pel-
* This rule is subject to frequent variations.
t Schumlansky. 
76
URINARY ORGANS.
vis in front of the rectum.   A similar  case has been seen by
Professor Hensinger.*   I have met with several instances of a
coalition across the spine, of the two kidneys, so as to present
the appearance of a bilobed organ.


      Of the Excretory Duct of the Kidney, or the  Ureter.

   The Ureter is a canal which conveys the urine from the kid-
ney to the bladder.   It commences in the centre of the kidney
by an enlargement called pelvis, which branches off into three
or four portions, (calices) one above, one below, and one or two
intermediate.   Each of these calices, is divided, at its free ex-
tremity,  into three  or four short funnel-shaped  terminations,
(Infundibula.)   Each of these terminations embraces by its ex-
panded orifice, the base of  a papilla* so as  to permit the  latter
to project into  it, and thereby to distil its urine there.   Very
frequently the number of papillas exceeds  that of the infundi-
bula, in which case two of the former  project into one of the
latter.
   The pelvis of the kidney  having emerged at the fissure be-
hind the  vessels, from being expanded  and  somewhat  conoidal
in shape is  reduced  to a  cylindrical canal,  which,  properly
speaking, is  the ureter:  the latter is about the size of  a goosc-
quill, and descends through the lumbar  region, between the pe-
ritoneum, and  the psoas magnus muscle.  It dips into the pelvis
by crossing in front of the primitive iliac vessels and the  inter-
nal iliac, crosses  the vas deferens  at the back of the bladder,
and penetrating obliquely the coats of  the latter,  terminates in
an orifice ten  or twelve lines  behind that  of the neck of the
bladder.
   The excretory duct of the kidney is formed by two coats.
The external is a dense, fibrous, and cellular tissue, but is des-
titute of any thing like muscle.   The internal is a thin mucous
lamina, which can be raised up without much difficulty, and is
continuous, at its lower end, with the internal coat of the blad-
der; at the upper end, it is  supposed by some anatomists to be
reflected over the papillas, and even  to pass for some  distance
into the tubuli uriniferi.  This duct has considerable powers of
• Am. Med. Jour. Vol. iii. p. 442. 
THE RENAL CAPSULES.
77
extension, as  manifested  by it transmitting  large calculi from
the kidney, and also, by its general enlargement in some cases
of obstructed  urethra; its sensibility is exquisite when irritated
by a calculus passing down it.


                   Of the Renal Capsules.

   The Renal Capsules (Capsular Renales, Renes Succenturiati,)
are two small bodies, one  on either side, placed upon the upper
end  of the kidney.  They are of a yellowish brown colour
tinged with red, have no  excretory ducts, and  are more dis-
tinctly developed and softer  in the perfect  foetus  than in  the
adult;  whence they are ranked among those organs, as the thy-
mus gland, and  others; which, having some peculiar value in
foetal existence, are perhaps  unnecessary to that of the adult.*
They are of a triangular pyramidal shape, flattened before and
behind, and rest by a concave base upon the kidney; they  are
about fifteen lines high and as many wide.
   They are surrounded by a  proper coat of lamellated dense
cellular tissue, which, by  detaching inwards its prolongations,
keeps the parts of these bodies together, and marks out their
divisions.   In the centre of the  renal capsule,  a cavity may,
from time to time, be found;  but, according  to my own obser-
vations, nothing in our structure  is less  certain than its exist-
ence;  and, in the opinion of  Meckel, when found, it is the re-
sult of cadaverous decomposition.  In the  foetus it contains a
reddish viscid fluid, which seems to consist in a large share of
albumen,  as it coagulates with alcohol; in  children, this fluid,
becomes yellow: in adults it U dark brown;  and in old people
it is  either  entirely deficient, or in a remarkably small quan-
tity.

   Of the Minute Structure of the Capsulae  Renales.—The
arteries of  these bodies come from  the emulgents, from  the
phrenics, and from the aorta.   The veins of the right one termi-
nate in the cava ascendens, and of the left in the left emulgent.

 * This opinion has recently been confirmed in a dissection of a foetus, where
t found the capsuloe renales, though the kidneys were absent,
                             8* 
78
URINARY ORGANS.
Each one is divisible into lobes, and by a slight  maceration
may be reduced into lobules and small granulations.   The ex-
ternal part is rather  more  consistent and  yellow than the  in-
ternal.  The granulations seem to  have  an intimate connexion
with the veins, as they are easily penetrated by fluid injections
from the latter.
  Alleged excretory ducts  for these  bodies  have been found
going to the testicles, to  the pelvis of the kidneys, and  to  the
thoracic duct, but no weight is  now attached to such asser-
tions.

                       Of the Bladder.

   The Bladder (Vesica Urinaria,)  is the reservoir for the urine,
 and is placed in  the  pelvis, just behind the  symphysis  of the
 pubes.  When pressed  upon, as it  commonly is, by the adja-
 cent viscera, it is flattened somewhat before and  behind;  but
 removed  from the body and inflated, it is an elongated sphere
 or an oval; the greatest diameter of which is vertical, in  regard
 to the linea ileo-pectinea.  The superior end of the bladder is
 called the upper fundus, and  the lower end the inferior fundus;
 the latter is  rather more obtuse than the other;  and between
 the two is the body.  The neck of the  bladder is its place of
 junction with the urethra.   The form of the bladder is influ-
 enced by age and by sex; in  very young infants it is cylindroid,
 and owing to the smallness of the  pelvis, rises up almost wholly
 into the  abdomen.   In  the  adult woman, who has frequently
 borne children, it is nearly spherical, has its greatest diameter
 transverse,* and is more capacious than in man.
   The bladder is bounded in front by the pubes, above by the
 small intestine, behind  by the rectum,  and below by the pro-
 state gland and the vesiculas seminales.   From its superior end
 there proceeds to the  umbilicus a  long  conical ligament, the
 urachus,  which is placed between the linea  alba and the peri-
 toneum, and  produces a slight elevation or doubling of the lat-
 ter.   In mankind, the urachus is  solid; some very rare cases,
 however, are reported, in which it  has been hollow, so as to
 permit the urine to flow through it from the bladder.  This vi-
* H. Cloquet, Anat. Dcscrip. 
THE BLADDER.
79
cious conformation has  generally been attended with a conge-
nital obstruction of the urethra.*   When the anterior parietes
of the abdomen are put upon the stretch, a semi-lunar fold of
the peritoneum, as formerly mentioned, is seen to proceed, on
either side of the urachus, from the lateral surface of the blad-
der  almost to the umbilicus.  These  folds contain,  in their
loose edge, the fibrous remains of the umbilical arteries of the
foetus, called, subsequently to  uterine  life, the Round Ligaments
of the bladder, though  they have  little or no influence on its
position.   The bladder is also fixed in its situation by the  pel-
vic  aponeurosis, a  membrane  elsewhere described  with  the
organs of generation.

   The bladder consists of four coats: the Peritoneal, the Mus-
cular, the Cellular, and the Mucous.
   The Peritoneal Coat is very imperfect, and is derived from
the  part of the peritoneum which  descends  from the anterior
parietes of the abdomen  into the pelvis.  It covers the upper
and the posterior  face of the bladder, and  then passes to the
rectum, by sinking down between these two organs, so as to
form the  small pouch beneath the lower fundus of the bladder;
the  apex.of this pouch reaches within an inch of the base of the
 prostate.  The upper margin of this pouch next to the bladder,
 forms a strong horizontal doubling, stretching across the pelvis,
 when the rectum is empty, and is on a level with the posterior
end of the vesiculas seminales.  Being  connected to the subja-
 cent muscular coat by a thin lamina of loose cellular membrane,
 the peritoneum may be dissected off without difficulty.   In con-
 siderable  distentions of the bladder, it is reflected from the up-
 per end of the latter to the abdominal muscles in a line much
 above  the pubes;  whereby a good opportunity  is afforded of
 reaching, with an instrument, the cavity of the bladder without
 injuring the  peritoneum.
   The Muscular Coat is  of a thickness  intermediate to that of
 the stomach and of the oesophagus, and its fibres are pale.
 They pass in very varied  directions,! a°d are  collected  into
 flattened  fasciculi, leaving interstices between them,  through
 which the internal coat is occasionally caused to  protrude, in
* Sabatier, Anat. vol. iii. p. 19.
t Santorini, Septemd. Tabul. 
80
URINARY ORGANS.
 strictures and other obstructions of the urethra.   These fasci-
 culi, for the most part, arise about the neck of the bladder, and
 ascending upwards, before, behind, and laterally, terminate at
 the superior fundus in the base of the urachus.   Within these,
 which may be considered as the longitudinal fibres of the blad-
 der, there are  others forming a" thinner lamina, whose course is
 transverse, or oblique: they serve to  connect the  preceding.
 As the muscular fibres are collected at the neck of the bladder,
 and at the urachus, there is, of course, an increased thickness
 at these points.
   The Cellular Coat consists in a close, dense, lamellated, and
 filamentous tissue, very extensible and  difficult to tear.   It is
 impervious to  water, adheres closely to the muscular coat with-
 out, and to the mucous within, so as to form a strong bond of
 union between them.   It is pervaded by many vessels  and
 nerves, which it conveys to the mucous coat.
   The Mucous Coat is also called the villous, but is much more
 smooth than the corresponding one of the stomach.  It is white,
 with a slight tinge of  red, and abounds with mucous follicles,
 which, though small and scarcely discernible in a natural state,
 are rendered very obvious by disease.  It stretches with much
 facility, but, like other mucous membranes, does not  restore
 itself  readily,  and is rather thrown, in the contracted state of
 the bladder, into wrinkles or folds, having a diversified course,
 and of a fugitive character, as they disappear  again upon the
 next distention.   It is very vascular.
   The internal face of this coat  presents, at its inferior part,
 the following appearances:

   1. The  Vesical Triangle (Trigonus Lieutaudi, Trigone Ve-
sicals) is placed immediately behind and below the neck of the
bladder, occupying the space between it and the orifices of the
ureters.  It is an equilateral triangle  of an inch in  length, its
surface is  smooth, is not affected  materially in extent either by
the dilatation or the contraction of the bladder, and is elevated
so as to be sufficiently distinct and well defined.

  2. The anterior angle of the triangle looks into the orifice of
the urethra, and is generally so elevated that it has obtained
the name of Uvula Vesicas; it is,  however, simply a  projection 
THE BLADDER.
81
of the mucous membrane depending upon the subjacent third
lobe of  the prostate;  which, at this point, is  not  unfrequently
much enlarged in the aged, and then presents a great difficulty
in the introduction of a catheter.

   3. The Orifices of the ureters form the posterior angles of the
triangle, and are contracted somewhat below the size of the ca-
nals themselves.  They are said, by  Sir Charles Bell,* to be
furnished, each one, with a small fasciculus  of muscular fibres,
which runs backwards from the orifice of the urethra, just be-
neath the lateral margins of the triangle, and, in its contraction,
will stretch the orifice of the  ureter so as to permit  an easy
passage of the urine into  the bladder.   The  retrogradation of
the urine is  prevented by the ureter  passing obliquely, for six or
eight lines, between the muscular and the mucous  coat; there is
something also in the obliquity  of the orifice itself which assists
in this effect; as I have  ascertained  by removing  the muscular
coat entirely, at this point, and dissecting up the ureter, not-
withstanding which, the  bladder, when inflated, still retained its
contents. Where the ureter penetrates the muscular coat, there
is often found a layer of longitudinal muscular fibres enveloping
it for half an inch, or an inch.

   4.  The Inferior Fundus of the bladder (bas-fond of the French)
is a depression of the general concavity of the bladder, of about
six lines in depth, placed between the base of the triangle and
the posterior side of the bladder.  In the erect  position, calcu-
lus, when one has it, lodges there.

   5.  The Internal Orifice of the neck of the bladder resembles
strongly that of a Florence flask,  modified,  however, by  the
projection of the uvula vesicas, which makes it somewhat cres-
centic below.  The neck of the bladder penetrates the prostate
gland, but, at its commencement, is surrounded by loose cellu-
lar tissue containing a very large and abundant plexus of veins.t
The internal layer of muscular fibres  is here transverse; and
they cross and intermix with each other in  different directions,

         * Med. Chir. Trans. Vol. iii.
         f Mascagni, Anat. Univ. Str. Prim. Tab. Spec. Fig. V. 
82
URINARY ORGANS.
forming a close compact tissue, which has the effect of a parti-
cular apparatus for retaining  the urine, and is called  Muscu-
lus  Sphincter  Vesicas Urinarias.  Generally, anatomists have
not considered this structure as distinct from the muscular coat
at large; but Sir Charles Bell, now a Professor in the University
of Edinburgh, whose  reputation as an anatomist is well esta-
blished, gives the following account of it:—
  "Begin the  dissection by taking off the  inner  membrane of
the bladder from around the orifice of the urethra.  A set of
fibres will be discovered, on the lower half of the orifice, which,
being carefully dissected, will be found to run in a semicircular
form round the urethra.  These fibres make a band  of about
half an inch in breadth,  particularly strong on the lower part
of the opening, and, having mounted a little above the  orifice,
on  each side,  they dispose of a portion of their fibres in  the
substance of the  bladder.  A smaller and somewhat weaker
set  of fibres will be seen  to complete their course, surrounding
the orifice on the upper part;  to these sphincter fibres a bridle
is joined, which comes from  the union of the  muscles of the
ureters."*
  After repeated observations on this point, I have come to the
conclusion that Mr. Bell has indicated a real structure; but  my
own dissections have resulted  as follows:  The inferior semi-
circumference of the  neck of the bladder  is surrounded by a
thick fasciculus of muscular fibre, half an inch wide, running
in a transverse direction, and  having its ends attached to the
lateral lobes of the Prostate Gland, being  above the third lobe
of the latter.   This fasciculus is perfectly  distinct from the or-
dinary muscular fibre of the bladder, and resembles in  its tex-
ture the musculo-fibrous coat of the  arteries.  The superior se-
micircumference is also surrounded  by a thin layer of muscular
fibres of an ordinary kind, forming a broad, thin band of a cre-
scentic shape,  the lower ends of which are  insensibly lost in the
adjacent muscular coat of the bladder by being spread out. And,
lastly, beneath the mucous membrane of the vesical triangle there
is a triangular muscle of the same size as the vesical triangle.
Having elongated angles, the  anterior angle may be  traced to
the posterior  part of  the caput gallinaginis, and the  posterior

           * Diseases of the Urethra, &c, p. 10.   Lond.  1820. 
THE BLADDER.
83
angles to the orifices of the ureters and the adjacent part of the
bladder.  The texture of this muscle is, also, like that of the
musculo-fibrous coat of the arteries.   When a bladder is recent,
this detail of structure is made out with difficulty: it  requires
to be previously  hardened in spirits of wine.  That a power
exists in the  neck of  the bladder of retaining completely the
urine, has been satisfactorily demonstrated to me in a case of
fistula in perineo, which was presented to the notice of the late
Dr.  Physick and myself, a few  years ago.*  Occasionally
there exists on each side of  the  neck of the  bladder, passing
from it to the pubes, a muscle of half an inch in breadth, the
effect of which is to draw the neck of the bladder towards the
symphysis pubis.  This is called by some the muscle of Wilson,
when it exists in  a distinct state it is evidently the anterior fas-
ciculus more detached than usual of the Levator Ani; but under
ordinary circumstances it appears  as  the anterior margin of
that muscle, and tnerefore does not attract special attention.
   As the urethra of the male performs the double office of con-
ducting both semen and  urine, it will be described more pro-
perly along  with the organs of generation.
   The urine has a considerable number of  constituents, the
 proportion of which varies according to age, health, and other
 circumstances.  Water forms about nine-tenths of it, the  re-
 mainder is an animal  matter insoluble in alcohol; uric and lac-
 tic acids;  lactate of ammonia; sulphate of potash and  of  soda;
 hydrochlorate of soda and of ammonia;  phosphate of  soda and
 of lime; and fluate of lime.
  P. S. Since the preceding forms went to press, the author
has had the perusal of a paper on the Anatomy and Pathology
of the Mucous Membranes, which presents in its anatomy the
closest coincidence with his own views expressed in Sect. 3rd,
Chap. III. of this volume.   This coincidence is the more gratify-
ing, as its author,? like the other European authorities who have
touched this subject under the same  views, does not appear to

  *  Chapman's Med. and Phys. Journ. 1824.
  t Rcclicrchcs Anatomiqucs sur la Membrane Muqucuse, vtc.  Par M. Na-
talis Guillot, L'Expcrienc?, p. 1«1, vol. i. Paris, 1837 38. 
84
URINARY ORGANS.
be acquainted with what was previously published here, in May,
1835, after having  been demonstrated in the Lectures  of the
preceding winter, by preparations still in existence.  All of these
contributions seem to be tending with great certainty, to a re-
formed Anatomy of the Gastro-intestinal mucous membrane,
such as was sketched in my papers alluded to, and in the last
edition, 1836, of this work. 
BOOK VI.
                   Organs of Generation.


                    CHAPTER I.

      OF THE ORGANS OF GENERATION IN THE MALE.

  The Male Organs of Generation consist in the Testicles and
in the Penis, with their appendages; or, in the language of some
anatomists, in  the  Formative and in the Copulative  Organs;
which distinction has been applied to both sexes.
                  SECT. I. — OF THE PENIS.

  The Penis, (Membrum Virile, Mentula,)  from performing
the two offices, one of which is the  conducting of urine from
the bladder, and the other the projection of semen into the fe-
male, has accordingly, a peculiarity  of structure, which allows
it to assume a state of collapse or of erection.  Its shape is al-
most cylindrical, but terminating in front by an obtusely pointed
extremity, named Glans.  It adheres by its posterior end or root
to the bones of the pelvis, at and below the symphysis pubis.
  It is formed by common integuments, by condensed cellular
tissue, by the  Corpus  Cavernosum,  and by the Corpus Spon-
giosum.

  The skin on the penis  is more thin and delicate than it is on
most other parts of the body, and is furnished with a conside-
  Vol. II.—9 
86
ORGANS OF GENERATION.
 rable number of sebaceous follicles or glands about ihe root of
 the organ, with hairs growing from the centre of them.  This
 same skin, in passing to the abdomen over the pubes, is some-
 what protruded by a subjacent deposite of fat and cellular mat-
 ter, causing an appearance corresponding with the mons vene-
 ris \of the female; and is also  generally thickly covered with
 short curly hair, which, as the individual advances in life, pro-
 ceeds in a  pointed direction to the umbilicus.  The skin of the
 penis is  but loosely connected to  the organ, so  that it slides
 readily backwards and forwards,  and  by its elasticity is  well
 suited to the varying states  of erection and collapse.  At  the
 anterior extremity it is thrown  into a duplicature or fold, the
 prepuce, (Prceputium;)  the internal lamina of which being
 fixed  circularly  to  the  penis, some  distance back from  the
 point, permits a considerable portion of that extremity of the
 penis, called the Glans, to project when  the prepuce is drawn
 back.  The under middle part of the prepuce is attached to the
 extremity of the  glans by a vertical longitudinal duplicature,
 called the Frasnum, which extends  to the orifice of the urethra.
   The skin does not  actually stop  at the circumference  of  the
 glans, but is  continued smoothly  over it, modified, however, so
 much in its structure, as to be much more  adherent, soft, deli-
 cate, vascular, and sentient: its  cuticle there is  a thin epithe-
 lium, readily separated by maceration.  The projecting circu-
 lar and oblique shoulder of the glans, behind which the skin be-
 comes firmly joined to the penis, is called  the Crown, (Corona
 Glandis.)  The contracted  portion, behind the  corona, is  the
 neck, (Collum.)  On  the surface  of the neck and the posterior
 face of the corona, the skin  is furnished with an  abundance of
 small glandular masses or follicles, (Glandulce Odoriferce Tyso-
 ni,)  which secrete the thick white sebaceous matter, (Smegma
prceputii,) that  accumulates when personal cleanliness is  not
 attended to.

   The penis, in addition to other modes of attachment  to  the
bones of the pelvis, is fixed by the  Ligamentum Suspensorium.
The latter is a triangular vertical fibrous lamina, which proceeds
 downwards from the symphysis pubis to the dorsum of the penis;
and,  according to Mr. Colles, envelops this organ to the glans,
forming its cellular coat, and being  continued into the fascia su- 
THE PENIS.
87
perficialis abdominis.   Posteriorly, it is lost insensibly on the
fascia of the thighs, covering the adductor muscles.  At its ori-
gin it is occasionally furnished with muscular fibres; one strong-
ly marked instance of which has been presented to me in my
own dissections.

  The Corpus Cavernosum of the penis, forms by much the
most considerable portion of the whole organ.  Externally, it is
a white fibrous membrane, of a dense structure, enjoying exten-
sibility and an extreme degree of contractility.  Its external
fibres pass, for the most part, longitudinally, except about the
root, where they  are blended with the periosteum of the bone,
and  with the tendons of the muscles. This coat of the penis is
occasionally called its elastic ligament.  It arises by two conical
crura, from the internal face of the crura of the pubes and ischia,
to within a little distance of the anterior part of the tuber ischii.
At the lower part of the symphysis pubis these crura join  and
form a body; which, when stripped of its connexions, resembles
two  cylinders united, lying  alongside of each other; and which
terminate in common, anteriorly, by a truncated cone, covered
obliquely by the glans.  At the posterior part of the corpus ca-
vernosum, in its centre, there  is a septum, almost complete, also
of the same elastic substance, which separates the two halves
from each other; but, anteriorly, this septum is more imperfect,
having an arrangement like  the teeth of a  comb, whence the
term Septum Pectiniforme  has been given it.   This septum is
continued at its margins into a layer of circular fibres, consti-
tuting the internal coat of the corpus cavernosum.
  In the middle of the corpus cavernosum, above, is a longitudi-
nal depression for lodging the veins of the penis, and, in the same
manner, there is another below, for the corpus spongiosum ure-
thras.  The cavity of this membrane is filled by a spongy tis-
sue, that arises from its internal face, and is formed of filaments
and little laminae;  they, by crossing each other, make a multitude
of cells, which  have a perfectly free communication with one
another, and generally are somewhat occupied by blood.  A fine
injection through  the artery of the corpus cavernosum will fill
these cells and return through the veins; from which cause the
cells may be  considered as intermediate to  the two orders of 
88
ORGANS OF GENERATION.
 vessels.  This opinion is the more probable from the cells being
lined by a thin membrane like the internal one of the veins, and
which is easily seen near the septum by tearing the spongy part
from it.

  The Corpus Spongiosum  Urethras extends from ten or twelve
lines behind the junction  of the crura of the corpus cavernosum,
to the anterior extremity of the penis.  Externally, it has a coat
resembling that of the corpus cavernosum, except that it is thin-
ner, and in its centre is the canal for the passage of urine.   Be-
tween the canal  and the coat is a spongy structure, much finer
than that of the corpus cavernosum, and though the cells com-
municate freely, still they have the appearance of convoluted
veins.  The corpus spongiosum is not of equal diameter in its
whole course, for its commencement in the perineum, where it
is pendulous, is enlarged  into what is termed the Bulb; from this
it diminishes  gradually to the anterior end, where it is again
enlarged into the glans penis.

  The Urethra is a mucous canal, whose length varies accord-
ing to the degree of erection in  the penis, and extends from the
neck of the bladder to the extremity of the glans.   It is curved,
and receives in its course the ductus  ejaculatorii, the excreto-
ry ducts  of Couper's glands, and the mucous lacunas of its own
internal membrane.  The  first part of this  canal which  tra-
verses the prostate  gland  is from fifteen  to  eighteen lines in
length, and is called  the Prostatic Portion: it is well supported
by  this body, although its own sides are very thin.   On its  in-
ferior surface is  a  doubling which constitutes  the Verumonta-
num or Caput Gallinaginis.   On either side of the  caput galli-
naginis the canal  of the urethra is  depressed into something
like a cul-de-sac, where  are to be found the lacunas of the pros-
tate gland.
  Between the Prostate  and the Bulb is the membranous part
of the urethra, about eight or ten lines long;  it is unprotected,
except by a soft  covering, which seems in  some measure to be
a mixture of gelatinous matter and muscular fibre.  The former
was considered by  Littre as a glandular body which secreted a
viscid humour into  the interior of the canal;  the latter, proba- 
THE PENIS.
89
bly, is the part described by Winslow as the inferior prostatic
muscle; which he asserted to arise on each side of the mem-
branous part of the urethra, and to be inserted into the corres-
ponding branch of the pubes near the symphysis.  The mem-
branous part of the urethra does not get into the end of the bulb,
but penetrates it from above, half an inch  or more occasional-
ly, from its extremity,  just below the junction of the crura of
the corpus cavernosum.
  The canal varies  in its  dimensions: at  its commencement,
which is synonymous with the neck  of the bladder, it is large;
it then contracts at the back of the caput  gallinaginis, and im-
mediately enlarges in the fore part of the prostate, at the'sides
of the caput.  The membranous part is small; the canal then en-
larges in the  bulb.   In the body of  the penis the canal is suc-
cessively diminished, till it  comes almost to the glans, when  it
is so remarkably enlarged  again as  to get the name of Fossa
Navicularis;  it terminates,  finally, by a short  vertical slit at
the extremity of the glans.
  The canal  of the  urethra is  formed of  a very thin mucous
membrane, on the outside of which is a dense filamentous cel-
lular  substance possessing great extensibility,  contractility
and elasticity.  The  mucous  membrane has great vascularity,
and its veins  are so superficial that they frequently bleed freely
upon  the introduction  of an instrument into the bladder, it is
also very sensitive.  The cellular coat on  its outside, whereby
it adheres to  the spongy structure, contracts sometimes in such
a  manner that circular fasciculated ridges simulating the pre-
sence of circular muscular fibres are seen  shining through, the
mucous coat, though when the  mucous  coat is peeled off this
arrangement  disappears.
   In the whole length of the canal there are two folds or lines,
one above, and the other below;  and  in the membranous and
spongy  portions,  excepting the fossa  navicularis,  longitudinal
folds of the mucous membrane also exist, which  are effaced by
distention.   The  fossa navicularis sometimes exhibits in the
contracted penis,  hardened in  spirits of wine, very superficial
folds of the  mucous  membrane  almost  transverse, in the nar-
row depressions between which we  see the orifices of very fine
mucous follicles.
   In the upper part of the canal there are a great many mucous
                            9* 
90
ORGANS OF GENERATION.
 lacunas;* Loder has marked about sixty-five: there is one par-
 ticularly large  in the  upper surface of the fossa  navicularis,
 which, it is said, has stopped the point of a bougie, and been
 mistaken for stricture.f

   Mr. Shaw has described a set of vessels  immediately on the
 outside of the internal membrane of the urethra; which, when
 empty, are very similar in appearance to muscular fibres.   He
 says, he  has discovered that  these  vessels form  an internal
 spongy body, which passes  down to the membranous part of
 the urethra, and forms even a small bulb there.J  His prepara-
 tion, being a quicksilver injection of the part, is certainly a very
 satisfactory demonstration of its existence; yet,in  my own ob-
 servations, where the blow-pipe has been resorted to, it has ra-
 ther appeared  to me to be  the cellular membrane connecting
 thecanal of the urethra with the corpus spongiosum.
   The arteries of the penis come from the internal pudic; some
 of its veins follow the course of the arteries, and others collect
 into the two venae dorsales  penis; the nerves come from  the in-
 ternal and external  pudics.


        SECT. II.--OF THE MUCOUS GLANDS AND APPARATUS.

   The  Seminal Vesicles (Vesiculcc Seminales) are two convo-
 luted tubes, one on  each  side, two inches in length, placed on
 the lower fundus of the  bladder, between it and the rectum,
 and  behind the prostate gland.  At their anterior  extremities
 they approach  very nearly to each other, being only separated
 by the intervention  of the vasa deferentia.   They  are fixed to
 the bladder, and surrounded by a thick  mass of adipose and
 cellular matter,  with many  bjood vessels,  principally  veins,
 passing through it.
   When inflated and dried, they present the semblance of cells,
 but are, in fact, long tubes; which  being convoluted, are  re-

  * Tabula Anat.
  | Sir Everard Home formerly communicated to the Royal Society a highly in-
teresting paper on the structure of the lining1 membrane of the urethra.  From
his microscopical observations he is induced to think that it is muscular.
  ^ Med. Chir. Trans, vol. x. 
PROSTATE GLAND.
91
duced to the apparent dimensions mentioned.   When dissected
and stretched out, they are four or five  inches long, by three
lines in diameter.
   There are also several pouches on each side of the long tube
which  increase  the  number of cells.  The  convolutions  are
preserved by the intermediate cellular tissue.   These bodies con-
sist of two coats: an external, which is a condensed  fibro-cel-
lular substance; and  an  internal, which is  mucous, being  a
continuation  of  the lining membrane  of the urethra.   They
are commonly filled  by a. drab-coloured thick  fluid, supposed to
be a mixture of the semen, with their own  proper  secretion,
though, of  this, Mr.  Hunter doubted.*  The  excretory duct of
each vesicle is about a line and a half long, when it joins in the
substance of the prostata  with the vas  deferens of the same
side; a  common canal  (ductus ejaculalorius) is  thus formed,
which runs parallel with its fellow, below the urethra.f
   The Ductus Ejaculatorius is  about eight or ten lines long, and
opens by an oblong  orifice, at the  lateral anterior face of the
 Caput Gallinaginis:  it  is larger behind than before, which gives
 it a conical shape, and allows fluids injected to pass freely from
 the vas deferens to  the vesicula, and  the  reverse.

   The Prostate Gland [Glandula  Paraslata) is  a body about
 the size and form of a horse chestnut, fixed on the neck of the
 bladder, and penetrated by the urethra, which traverses it much
■ nearer  its  superior  than  its inferior surface.  The base of  it is
 turned backwards, and the point forwards; its inferior surface
 rests upon  the rectum ; it is rendered concave by that circum-
 stance,  and its sides, in  the distentions of this organ  by fasces,
 are overlapped by it.  The Prostate  has, posteriorly, a notch in
 its centre,  which divides it into two lateral lobes, and by raising
 the Vesiculas Seminales, we see where  their excretory ducts pe-
 netrate  the gland, and  separate from the body of it, the little tu-

   * Observations on the Animal (Economy.
   f In a dissection executed at the University by Dr. Joseph Togno, a muscle
 was found on the inferior surface of the seminal vesicles arising from the pros-
 tate gland, and inserted into them.  This is said  to  be a common arrangement in
 some animals. 
92
ORGANS OF GENERATION.
bercle, to which Sir Everard Home* has particularly called the
attention of the profession, and considered as a Third Lobe; it
being certain that it is frequently the seat of disease and tume-
faction.
  On the under surface of the canal formed in the prostate, by
the urethra, is, as mentioned, the oblong  elevation called the
Verumontanum, or Caput Gallinaginis.  It commences a little in
front of the  uvula vesicas, and, being broader and higher behind,
comes to a point very gradually before; it  is about eight or ten
lines long.   Along the posterior part of this ridge a long  cleft
is sometimes found, it being the orifice of a lacuna, first observed
by Morgagni; and in front of it are the orifices, bordering upon
each other,  of  the ductus  ejaculatorii, very superficial folds of
the lining membrane, some three or four in number, radiate from
the anterior end of the  caput to the anterior end  of  the mem-
branous  portion of the urethra.
  The prostate consists in a condensed, white, extensible, though
easily lacerated fibrous cellular tissue, within which are placed
a greatnumber of mucous follicles, that have from eight to twelve
ducts, or, according to Loder, from thirty-two to forty-four, pass-
ing obliquely forwards, and terminating in the urethra, as stated,
at the  sides of the urethral crest, or caput  gallinaginis.   The
fluid secreted  is thick, ropy, white,  and semi-transparent,  in a
healthy state.   The prostate is surrounded  by a fibrous capsule,
to be described.
  The lacunas  of the third lobe penetrate the coals of the blad-
der, behind  the caput gallinaginis.

  Of the Glands ofCouper.—These glands are also intended for
the secretion of mucus, or a fluid  very much like it, into the ca-
nal of the urethra.  They are two in number, one  on each side,
and are situated in advance of the prostate, between the laminas
of the  triangular ligament, at the point where the bulb  of the
urethra adheres to it.  Commonly, they are about the size  of a
garden pea, but not unfrequently much smaller, and, in some in-
stances, cannot be found at all, which induced Hiester to declare,
that he had  searched for them fruitlessly.   They are yellowish,
hard, and consist of several lobules united together.  Each one
* Diseases of Prostate. 
THE TESTICLES.
93
 has an excretory duct that receives readily a bristle, and passes
 obliquely forwards, between the corpus spongiosum and the ca-
 nal of the urethra, to terminate in an oblique orifice in the latter,
 about an inch distant from the gland.
   One or more glands, of the same description, and discovered
 by Littre, are occasionally found just in front of Couper's.  They
 also discharge their secretion  into the adjacent part of the  ure-
 thra.  In my own dissections I have not met with  them.


                 SECT. III.--OF THE TESTICLES.

   The Testicles  (Testes, Didymi) are  two in number, one for
 each side of the  scrotum.  Being the  seat  of the  secretion of
 sperm or the male prolific'liquor, their function is of the first im-
 portance in the act of generation.   They are of an  oblong oval
 form, somewhat compressed laterally;  and present  their edges
 forwards and backwards.   From being suspended near the mid-
 dle of their posterior  edge by the spermatic chord, the upper
 end points somewhat forwards, while the lower one is directed
 in the same degree backwards.  They are about an inch and a
 half long, by one inch in breadth, and eight or nine lines in thick-
 ness.   They are of equal size generally, but  in case of  a diffe-
 rence it  is in favour of the right; the latter is also  remarkable
 for being suspended higher than the left, a feature in ancient
 statuary so  universal, as to prove the  vigilance and accuracy
 of the sculptors of those days, in regard to the proportions  and
 peculiarities of the  human form.   "Two obvious  advantages
 attend this arrangement: one,  that of the testicles passing each
 other without the  collision when the thighs are brought together;
 and another, the facility of keeping the  penis to one side, instead
 of straight forward in the middle line of the body."*
  The testicle is enveloped  by several tunics;  they are  the
 Scrotum, the Dartos, the Tunica Vaginalis, and the Tunica Al-
 buginea.

  The Scrotum is merely a continuation of  the common skin
 from the inner side of the thighs, the perineum, and the  penis,
and is common to the two  testicles.  It is a  symmetrical bag,

               *  Sir A. Cooper on the Testis.  1830. 
94
ORGANS OF GENERATION.
and the two halves are marked off from each other by a middle
line or elevation of the skin, called the Raphe, which begins in
the perineum at the anus, and, winding around the scrotum, is
continued along the under surface of the penis to the prepuce.
  The skin of the scrotum  is thin, darker than elsewhere, bat
has a thick, strong epidermis; it has many sebaceous follicles in
it, and is sparingly furnished with hair.  It is very extensible, as
manifested in fatigue, and by hydrocele; and may be contracted
again so as to draw the  testicles close under the pubes, though
for the latter power it  principally depends upon  the subjacent
coat.  Its surface is covered with wrinkles, for the most part
transverse, and ending at the raphe:  they are effaced during its
great distentions in hernia and dropsy, and then it has a smooth
shining surface.

  The Dartos is placed within the scrotum, and forms two dis-
tinct sacs or tunics, one  for each  testicle.   It arises from the
inferior margins of the crura of the ischia and of the pubes, and
lines the scrotum till it reaches the  raphe; it is then reflected
upwards to form  the partition between the testicles, (septum
scroti,) and terminates at the corpus  spongiosum urethras.  This
membrane, according  to the observations of MM. Chaussier,
Lobstein, and Breschet,* does not exist in  the scrotum till the
descent of the testicle, and then appears to be an expansion of
the gubernaculum testis.
  It receives a  considerable number of blood vessels, which,
owing to the thinness of the skin, may be seen in the living body,
ramifying  through its  substance: its general appearance is,
therefore, reddish.  It is destitute of fat,  and consists in long
fibres much matted together, and passing in every direction:
they are easily separated by distention with air or water, and
by slight maceration. Its powers of contraction are exceeding-
ly well marked upon the application of cold to the scrotum, from
which cause it  has  been  considered by  many anatomists as
muscular:  the only distinct  evidences, however, which I have
met with of a resemblance to the  latter, have been found gene-
rally on its posterior face, near the perineum.f  From its equi-
  *  Dictionnaire des Sciences Med. tome viii.
  t  Since the first edition, I have dissected one subject, (January, 1830,) where
the fibres were evidently muscular, though interwoven. 
THE TESTICLES.
95
vocal character, J. F. Meckel has very ingeniously suggested
that it forms the transition from cellular to muscular tissue, and
that there exists between it and other muscles the same relation
that there is between the muscles of the superior and of the in-
ferior orders of animals.  Among the latter, the fibrous struc-
ture is indistinctly marked, and is masked by gelatine; an ele-
ment  of the cellular tissue which envelops  and  conceals the
fibrine, an element of the muscular tissue.

  The fibres of the cremaster muscle, which are next in order,
form  a very imperfect covering to the testicle, and belong rather
to the spermatic  chord: what remains  to  be said concerning
them will be more properly introduced into the account of the
latter. The cellular substance that connects thedartos and the
cremaster with the tunica vaginalis forms a compact and perfect
lamina, sometimes spoken of as the Tunica Vaginalis Communis
Testis.  There is one for each testicle, which it surrounds en-
tirely, as  well as  its chord, and connects the chord to the mar-
gin of the external abdominal  ring, as stated in its account.
At its upper end it is continuous  with the cellular substance that
unites the peritoneum to the parietes  of the abdomen, as may
be proved by inflating  it, when  the air will penetrate  accord-
ingly through the abdominal  canal.

   The Peritestis, or Tunica Vaginalis, was originally a process of
peritoneum, communicating with the cavity of the latter through
the abdominal  canal; but in the  adult, it appears as a complete
and  distinct sac.   As it is  very  rigidly comparable to a double
night-cap drawn  over  the  head, we accordingly find  that the
testicle, along with the epididymis is pushed into it from behind.
That portion of the tunica vaginalis which is in contact with the
testicle, or rather with the  tunica albuginea, adheres so closely
that it cannot be separated, except very partially and in shreds;
but it may be detached easily from the epididymis, with the con-
volutions of which it is in immediate contact.  This sac is longer
and  larger than the  testicle itself, from which cause it ascends
for several lines above the  superior end of the gland, and  the
free part  hangs loosely about it.   Its cavity may, with but little
force, be  injected so as to hold an ounce or two of fluid.
   This membrane is smooth and  polished on the surface forming 
96
ORGANS OF GENERATION.
 its cavity, and contains a small quantity of serous halitus, which
 allows the opposed surfaces to glide freely upon one another. Its
 exterior connexion with the dartos is so slight that it may be
 withdrawn without dissection, with the exception of an adhesion
 at the lower end of the testis arising from the remains of the gu-
 bernaculum: in such case, however, it still continues to be in-
 vested by the tunica vaginalis communis, from which it can only
 be removed by a  special dissection.

   The Tunica Albuginea is the proper coat of the testicle, is in
 immediate contact with its  glandular structure, and serves to
 maintain its shape, as well  as to protect it from pressure. From
 its internal surface proceed many membranous, horizontal fibres,
 which form partial partitions of its cavity (Septulce Testis) and
 incline* towards its posterior part, where they terminate in a lon-
 gitudinal projection, called Corpus Highmorianum.   The latter
 is of a prismatic shape, somewhat broader above than below,
 and  is of but little consequence, except that it was once errone-
 ously supposed to be a sinus, into which the seminiferous tubesdis-
 charged. Sir Astley Cooper proposes to call this the mediastinum
 testis, and considers the Corpus Highmorianum as being formed
 by an inflection of the tunica albuginea.   The Septulae Testis,
 he asserts, really envelop the seminiferous tubes, by forming bags
 which support, confine, protect, and nourish the tubular struc-
 ture of the testis.*  The albuginea is perforated by several fo-
 ramina along its posterior margin, where there is a deficiency
 of tunica vaginalis for  the passing  of excretory ducts and blood
 vessels.
   This  membrane is  dense,  strong, white, and fibrous, resem-
 bling in structure the tunica sclerotica of the eye, and the dura
 mater of the brain.  Sir A. Cooper considers the tunica albugi-
 nea as consisting  of two layers which can be readily separated
by dissection, excepting in front; the outer layer is the fibrous
one,  while the internal one, which  he calls Tunica Vasculosa,
has the  spermatic arteries and veins ramifying upon it.  They
are rendered  very distinct from each other by a minute injec-
tion.t

  * Observations, &c. on the Testis, p. 14.  London, 1830.
  fid. 
THE TESTICLES.
97
  Of the Minute Structure of the Testicle*—The glandular por-
tion  of the testicle  consists in a congeries of convoluted tubes
(Tubuli Seminiferi) amounting to 300, according to Dr. Munro;
and whose aggregate length is 5208 feet.  The diameter of each
one does not exceed one two-hundreth part of an inch,  and its
length is somewhat short of seventeen and  a half feet.  These
tubes form convolutions or  hanks, the  threads of which are ser-
pentine, very much like the thread of a ravelled stocking; and
a re held together by a delicate cellular substance easily softened
by maceration. Each tube forms of itself a hank or lobule, which
is kept distinct from the adjacent ones by the septulae or parti-
tions of the  albuginea, and may be easily picked out from them.
Their extreme tenuity and delicacy  of structure  cause them,
when well macerated, drawn out with a pin, and then suspend-
ed in water, to resemble a tangled skein of fine silk.
  The tubuli seminiferi finally terminate in straight tubes, called
the Vasa Recta, which unite near the centre of the testicle in a
somewhat complicated arrangement, obtaining  the name of the
Rete Vasculosum Testis.   From the  latter there proceed from
twelve to eighteen  ducts (Vasa Eferenlia) which go upwards
and backwards to penetrate the corpus Highmorianum and the
tunica albuginea.  Each of these vasa efferentia is then  convo-
luted upon itself into a conical body, called Conus Vasculosus,
which presents its base backwards. Each cone, at its base, has
its tube entering successively into  the tube of which the Epi-
didymis is formed.
   Notwithstanding  the extreme tenuity of  these  several ar-
rangements in the excretory ducts of the testicle, they may be
entirely filled with  quicksilver  from the  vas  deferens; but the
task is one of great difficulty, and rarely succeeds.
  The  epididymis is the prismatic arch which rests  vertically
on the  back of the testicle, and adheres to it by the  reflection
of the tunica  vaginalis.  It is  enlarged  at both ends,  the upper
of which, being  formed by the  Coni Vasculosi, is called the
Globus Major, and the lower enlargement is the Globus Minor.
It is formed of a single convoluted tube, of the fourth of a line
in diameter.   After this tube has got to the lower end of the

  * Hunter, Med. Comment, p. 1. 1777.  Albinus, Acad. Annot. Lib. ii. Loder,
Tab. Anat. Uuysch, Thes. Anat. iv.  Ilaller, Op. Min. tom. ii. Alex. Munro, de
Testibus, Ed. 1755.
  Vol. II.—10 
98
ORGANS OF GENERATION.
globus minor  it becomes less convoluted, enlarges, turns up-
wards on the inner side of the epididymis, and obtains the name
of Vas Deferens.  Before it reaches the  top of the epididymis
it has become  perfectly straight, or almost so.   There is a blind
duct which begins at the top of the epididymis and terminates
below:  the object of it is not understood.


                  Of the Spermatic Chord.

  The Spermatic Chord  is a fasciculus of about half an inch in
diameter, which may be felt very readily  through  the skin of
the scrotum, passing from  the upper end of the testicle to the
external  abdominal ring.  It is formed  by the Vas Deferens;
the Spermatic Artery and  Veins;  the Lymphatics of the Tes-
ticle; and the  Nerves;  all being covered  in by the  Tunica Va-
ginalis Communis, and by the Cremaster  Muscle.

  The Cremaster Muscle,  also  called the  tunica elythroides,*
being derived from  the  internal  oblique and  the  transverse
muscle of the abdomen,f forms a very  complete  envelope  to
the chord from the abdominal ring to the testicle.   But when
it reaches the  latter its fibres spread out and become indistinct
upon the tunica vaginalis  communis, as they  there  consist  in
small, pale,  scattered fasciculi; many of which terminate in-
sensibly, while others form on the front of  the tunica vaginalis
loops, having their convexities downwards. This muscle draws
the testicle upwards, an action very different from the corruga-
tion of the scrotum.

  'She-Vas Deferens, or  the proper excretory  duct of the testi-
cle, is a white tube of about a line and a half  in diameter, and
has  a cartilaginous  feel.  Its parietes are thick,  as its cavity
will not receive a body larger than a bristle, without being put
upon the stretch.  It traverses a long space, and  in doing so,
first passes at  the back of the chord  from its commencement to
the internal abdominal ring:  having reached the latter, it then
abandons the  spermatic  artery and  vein, and  dipping into the
pelvis, by the  side of the bladder,  goes between the lower fun-
* EAi/7gov a sheath.
f See Abdominal Muscles. 
THE TESTICLES.
99
dus of the latter and the  ureter.   It  then converges towards
its fellow, along the  under extremity of the bladder, at the in-
ner margin  of the vesicula  seminalis of the same  side, and
finally terminates in the urethra near the neck of the bladder, by
forming the Ductus Ejaculatorius with the assistance of the duct
of the adjoining  vesicula  seminalis.   About two and a half
inches from its termination, it enlarges and becomes somewhat
tortuous.
   This duct consists of two coats: the external one is  hard,
compact, and occasionally, fibres are seen in it; but its  struc-
ture is not very evident,  and is  peculiar.  The  internal is a
mucous membrane.
   For the description of  the  remaining portions of  the chord,
see Spermatic Artery, Vein, Lymphatics, and Plexus of Nerves.

   The Testicles undergo  a remarkable change in their position,
from the earliest developement of their rudiments to the perfect
foetal  state.  They are not formed in the  scrotum, but  in the
abdomen just below the kidneys; from which position they are
gradually transferred   About the middle of the third month of
gestation they are two lines long, and placed behind  the perito-
 neum, to which they loosely adhere.  The vas deferens then,
 instead of rising up on the side of the epididymis, goes straight
 down into the pelvis.  At this period may be seen the gubernar
 culum testis, discovered by J. Hunler,* which becomes more
 distinct in  a few weeks  afterwards, and assumes a triangular
 appearance.  This gubernaculum has the office of drawing the
 testicle down into the scrotum; its point commences in the up-
 per part of the latter, somewhat below the  external abdominal
 ring; it passes through the abdominal canal, ascends upon the ilia-
 cus internus muscle, and  is attached by its base to the inferior
 end of the testicle.   In front of the gubernaculum, a process, or
 small pouch of peritoneum, passes through the abdominal canal
 to the upper part of the  scrotum.  By the  contraction  of the
 gubernaculum, the  testicle is brought,  about  the seventh or
 eighth month, into  the scrotum, by sliding down behind the
 pouch.  The lower end of the pouch, at which the  testicle  is
 finally arrested, becomes  the tunica vaginalis testis.
* Med. Comment. Lond. 1777. 
100                ORGANS OF GENERATION.
  As soon as the testicle has reached the scrotum, the neck of
the pouch has a tendency to close and to become obliterated,
which is commonly accomplished at the period of birth; yet it
sometimes remains open for a longer time and becomes the oc-
casion of congenital hernia.   Very generally, at  birth, the ori-
fice of the pouch will receive the end of a-probe to the depth of
a  line or  two; but all below is perfectly closed, and has its
structure so condensed and altered, that no one, from a view of
it alone, would  suppose that the cavity of the  tunica vaginalis
had ever communicated with that of the peritoneum.*
*

    SECT. IV.—OF THE  MUSCLES AND TASCIM OF THE  PERINEUM.

                       Perineal Fascia.

   The Perineal Fascia is placed just beneath the skin of the
perineum, and covers the muscles.   It is spread over nearly all
the space  between  the anus and the posterior  margin of the
scrotum, and between the rami of the pubes and the ischia on
each side: it is very  firmly fixed to these bones, and is gradu-
ally blended with the  cellular substance of the posterior part of
the scrotum.  This fascia is rather thin, but, in case of a rupture
of  the posterior part of the  urethra, prevents  the urine from
showing itself in the  perineum, and drives  it into the cellular
structure of the scrotum.  In abscesses of the perineum, it also
prevents the fluctuation from being very evident.


                 The Musculus Erector Penis,

   Is so situated, as to  cover  the whole of the erus of the penis
which is not in  contact with the bony margin of  the pelvis.  It
arises, therefore, tendinous and fleshy,  from the anterior part of
the tuber ischii; its fleshy fibres adhere to the internal and ex-

  * The explanations and anatomy of this process have been treated at large in
the following works:
  Girardi, Tabul. II. adj. Septemd. Tab. Santorini.
  Hunter, Observations on  certain parts of the Animal (Economy.  WVHunter,
Med. Commentaries.
  Edwardi Sandifort, Opusc. Anat.
  Wrisberg Comment. Medic. Physiolog., &c. 
MUSCLES AND FASCIAE OF THE PERINEUM.
101
ternal margins of the ramus of the ischium, and of the pubes,
and proceed upwards: just before the union of the crura of the
penis, they end in a flat tendon which is lost on the side of the
corpus cavernosum of the penis.*
   Its use is not well understood.
              The Musculus Accelerator Urina,

  Lies on the bulb  and back  part of the corpus spongiosum
urethras: it is a thin muscle, consisting of oblique fibres.
  It arises by a pointed production from the side of the body of
the penis; its origin is continued obliquely across the inferior
surface of the crus  penis, where the  latter begins to form the
body of the penis.  It arises, also, for an inch from the inner side
of the ramus of  the  pubes, between the crus penis and  the tri-
angular ligament of  the urethra.  The muscles of the opposite
sides are inserted into one another by a white line, which marks
the middle of the bulb  of the urethra; and by a point, into the
anterior extremity of the sphincter ani, where they  are joined
by  the transversi perinei.

  In order to see the origin  of these muscles very  distinctly,
separate them from each other in the middle line, and dissect
them from the corpus  spongiosum.  Cut transversely through
the corpus spongiosum about three inches before the triangular
ligament, and dissect it clearly from the corpus cavernosum,
turning it downwards  so that it may  hang by the membranous
part of the urethra.  By putting the  two acceleratores on the
stretch, it will be seen that besides the origins mentioned, they
arise, also, from each  other by a tendinous membrane that  is
interposed between the corpus spongiosum and cavernosum ; so
that they literally surround the back part of the urethra, consti-
tuting a complete sphincter muscle for it.  This account of the
accelerator urinas being peculiar to myself, is adopted from a
strong analogy between it  and  the sphincter vaginas.
   The two muscles are considered by M. Chuussieras forming

  * The late Dr. Lawrence informed me that he had frequently found muscular
fibres between the bone and the crus penis.
                            10*
*4Ss
 
102
ORGANS OF GENERATION.
but one: in that case its origin will be reversed, and commence
in the middle line of the perineum instead of terminating there.
As this  muscle, and the erector penis,  touch by their conti-
guous faces, it is difficult to get into the membranous  part of
the urethra in lithotomy without  cutting through the muscular
fibres of one or the other.
   It propels the urine and semen forward.

               The Musculus Transversus Perinei,

   As its name implies, passes  directly across the perineum; it
 arises from the inner side of the ischium, just at the origin of
 the erector penis, and is inserted where the sphincter ani and ac-
 celeratores urinas join.
   I have observed that when the lower part of the accelerator
 was extended much below its usual line, and  strongly deve-
 loped, that the transversus was very irregular in its origin and
 course; consisting frequently of a few fibres which did not de-
 serve the name of a distinct muscle, and lying almost unappro-
 priated in the adipose matter of the part.
   Occasionally, a fasciculus of muscular fibres exists, called, by
 Albinus,'/Transversus Perinei Alter, which arises in front of the
 transversus: it seems generally to  be a loose fasciculus of the
 accelerator urinas muscle, and is inserted into the perineal junc-
 tion just behind it.
   The  use of these muscles seems to be  to contribute to fix the
 bulb of the urethra.

                 The Musculus Sphincter Aniy

   Consists in  a plane an inch thick, of elliptical fibres imme-
 diately beneath the skin of the anus, and which surrounds the
 latter in order to keep it closed.  The long diameter of the el-
 lipsis is extended from the coccyx towards the symphysis pubis,
 and has its angles very much elongated; the anterior may be
 traced  terminating insensibly in the posterior face of the scro-
 tum.   It has two fixed points, the  last bone of the os coccygis
 behind,, and perineal union of the other muscles in front; its la-
 teral diameter occupies about one-half of the space between the
 tuberosities of the ischia, and it is in the middle of this space, 
MUSCLES AND FASCIAE OF THE PERINEUM.
103
  Besides closing the orifice of the rectum it will draw the bulb
of the urethra backwards, or  the point of the os coccygis for-
wards.

                  The Musculus Coccygeus,

  Belongs to the interior of the pelvis.  It arises by a small,
tendinous, and fleshy beginning, from the spine of the ischium,
and, lying on the anterior face of the anterior sacro-sciatic li-
gament, it is inserted  into the side of the  last bone of the sa-
crum, and of all those of the os coccygis.
   It draws the os coccygis forwards.
   It frequently happens that there is on each side a small fasci-
culus of muscle arising from the inferior bone of the sacrum in
front, and inserted into the bones of the coccyx; it is called
Sacro-Coccygeus.
   A large quantity of adipose and cellular matter exists on the
side of the rectum, between it  and  the  parietes of the pelvis,
concealing the perineal surface of the levatores ani muscles.


                  The Musculus Levator Ani,

   Arises, fleshy, from  the back of the pubes near its symphysis,
 and from near the superior margin of the foramen thyroideum
 above the obturator internus muscle.   It also arises  from the
 aponeurosis  pelvica, where this membrane is extended as a
 thickened semi-lunar chord from the superior margin of the thy-
 roid  foramen towards the spinous process of the os  ischium,
 This second part of the origin of the levator ani  is defectively
 described in most books on anatomy,   It is then  seen to  cross
 obliquely, as far as the spine of the ischium, that portion of the
 obturator internus which arises from the plane of the ischium.
   From this extensive origin  the fibres  converge and descend
 backwards, and have  three distinct places of insertion; the pos-
 terior fibres are inserted into the two last bones of the os coccy-
 gis;  the middle, and  by far  the greater number, are inserted
 into the semi-circumference  of  the rectum between its longitu-
 dinal fibres and the circular fibres of the sphincter  ani; and,
 finally,  the most anterior fibres pass obliquely downwards and
 backwards on  the side of the vesical end  of the membranous 
104                ORGANS OF GENERATION.
part of the urethra, and on the  side of the prostate gland, and
are inserted into the common place of junction of the perineal
muscles.

          The Triangular Ligament of ihe Urethra,

  Is a membrane which fills up the space below the symphysis
of the pubes, and answers there as a septum between the peri-
neum and the  pelvis: when closely examined, it is seen to con-
nect itself to the  internal edges of the rami of the pubes and
ischia on the inner posterior sides of the crura penis as far down
as the beginning of the latter.   At its lower edge its ligamentous
character is not so well defined.  On its anterior surface is the
bulb of the urethra, and just at the extremity of the latter, en-
closed by the ligament, and adhering to it, are Couper's Glands.
In contact with it behind, and adhering,  is the  prostate gland,
covered by its fibrous capsule,  which is  a  continuation of the
pelvic aponeurosis over it.  A perforation exists  in  it, through
which passes the membranous part of the urethra.   This open-
ing is not very apparent, in consequence of its edges being con-
tinued a little distance on the canal; but by detaching them the
whole becomes well defined.
  The relative situation of the bulb and of the membranous part
of the urethra is such, that the former goes towards the anus,
while the latter passes upwards towards the neck of the bladder;
they,  consequently, form a considerable angle with each other.
The membranous part of the  urethra is  much the deepest, the
recollection of which is all-important in lithotomy, as it teaches
us to  avoid the one, and lo cut into the other.  It may  also be
observed, that  the hole in the  triangular ligamenl  is an inch
below the symphysis pubis.
  By removing the upper corner of the triangular ligament, we
are made acquainted with  another just behind it, which is total-
ly distinct.  This ligament is half an inch broad, is thick and
strong, particularly at its lower edge, and  is very firmly attached
laterally  to each of the pubes, just  below  the symphysis: it is  a
continuation of the ligamentous union of the symphysis pubis.
Mr. Colles calls it pubic ligament, with great propriety.  I would
suggest, as somewhat more expressive, the term Inter-Pubic Li- 
MUSCLES AND FASCIAE OF THE PERINEUM.
105
 gament;* as it serves to distinguish it from another called Pubic,
 which is above the pubes, and described in the account of the
 recti abdominis muscles.  The breadth  of this having  been
 stated at half an inch, it is obvious that the hole in the triangu-
 lar ligament is half an inch below its lower edge.


                        Pelvic Fascia,

   The Pelvic Fascia (Aponeurosis Pelvica) connects the bladder
 to the sides of the pelvis.  " This fascia descends from the ileo-
 pectineal line to about midway in the depth of the pelvis; here
 it is reflected  from the surface of the muscle, (the Levator Ani,)
 and applies itself to the prostate gland and bladder on the body
 of which it is  ultimately lost.   At the angle of its reflection, this
 fascia appears particularly strong and white, but becomes more
 weak and thin as it lines the muscle and  covers the bladder.   In
 tracing  this membrane it will be seen that from the pubes just
 below the symphysis, a pointed production of it, constituting its
 anterior  margin, is fixed into the side of the neck of the bladder.
 This pointed production on each side is called, by most anato-
 mists, the anterior ligaments of the bladder.   Between them,"
 just beneath the symphysis of the pubes, a pouch large enough
 to receive the end of the finger, is formed  by the union of the
 fascias of the two sides: this pouch connects the middle anterior
 part of the neck of the bladder to the lower margin of the sym-
 physis pubis, "f
   This fascia adheres^closely to the periosteum of the pubes,
 between the upper margin of the thyroid foramen and the crista
 of the pubes;  about the middle third of the linea innominata it
 is obviously a continuous membrane  with the iliac fascia which
 covers the iliacus internus muscle;  but behind this, again, it
 arises from the remaining third of the linea innominata.
  The portion of this fascia which Mr. Colles speaks of as par-
 ticularly  strong and white, forms a bow, the concavity of which
 looks upwards, one end of the  bow being fastened to  the pubes
 above the foramen thyroideum, and the other end to the  ischium
 above its spine,  The perineal surface of this bow is an impor-
tant point of the origin of the levator ani.   Above the bow this

    * See Symphysis Pubis.            f Colles' Surgical Anatomy. 
106
FEMALE ORGANS OF GENERATION.
fascia is very thin, for the fibres of  the obturator internus can
be readily seen through it.
  At the bow the fascia divides into two laminas; one pursuing
its course to the bladder and rectum, the other covers the lower
part of the obturator internus muscle, and thereby constitutes
the obturator fascia.   The  levator  ani is interposed between
these two laminas.  The aponeurosis pelvica also forms a bow
or semi-lunar edge in front of the sacral nerves.  The triangu-
lar ligament and this fascia are so identified in forming the
capsule of  the prostate, that the latter, in description, may be
referred either to the one or the other, or to both, according to
the fancy of the describer.
                    CHAPTER  II.

     OP THE ORGANS OF GENERATION IN THE FEMALE.

  The Copulative Organs in the female are, the Vulva and the
Vagina-, the Generative are the Uterus and the Ovaria.

                  SECT. 1.—OF THE VULVA.

  The term Vulva is applied to the most superficial  of the co-
pulative organs, and consists in the Mons Veneris,  the Labia
Externa, the Labia Interna, the  Clitoris, the  Vestibulum, the
Orificium Urethras, the Fourchette, and*the Fossa Navicularis.

  The Mons Veneris is the protuberance on the fore part of the
pubes.  Its size varies considerably, according to the state of
obesity of the subject, in consequence of its being formed by a
deposite of fat  between the skin  and the bone:  in  corpulent
women it is very large and prominent, whereas, in such as are
much emaciated, it simply describes the outline of the bones.
The skin, there, is abundantly furnished with sebaceous glands,
seated in the cellular texture beneath it, and about the size and
shape of millet  seed.  At the age of puberty a  growth of hair
takes place upon it, which is not so long  as  the correspondent
growth upon men, and is not so much disposed to spread itself
over the lower part of the abdomen as life  advances.  In wo- 
THE VULVA.
107
men who have abused coition, it is said that these hairs become
much curled.
  The Labia Externa are a continuation of the mons veneris
downwards in the form of an oblong eminence  on either side.
Their elevation is produced in the same way by a deposite  of
fat beneath the skin.  They are somewhat broader and more
prominent above than below.  On the side which is next to the
thigh, the integument  is common skin,  sparingly covered with
hair;  but on the other face it is a mucous  membrane, being a
continuation of that of the vagina.  The skin here, as well  as
at the commencement of every mucous membrane, is insensi-
bly changed into the latter.  They have  many sebaceous glands
externally, and mucous glands internally, upon them.
  Much cellular membrane, like that of the scrotum, is found
in their interior structure;  whereby they enjoy  great extensi-
bility in order to favour the dilatation of the  parts in parturi-
tion.  The rima which  exists  between them is  the Fissura
Vulvas of  authors, and is about twice the length of the orifice
of the vagina; this arrangement of it gives increased facility to
the  expulsion of the fcetus.

  The Fourchette or Frenulum Vulvas, is situated at  the poste-
rior commissure of the labia externa,  and is a thin, narrow
transverse duplicature of skin;  which, owing  to its weakness,
is most frequently ruptured at the first act of parturition, and
then disappears.

  The Clitoris  bears,  in  some respects, a  resemblance  to the
penis of the male, but is by no means so large.  It  is situated
immediately below the symphysis pubis, and  consists in a cy-
lindrical body of three or four lines in diameter, with two crura.
The body  is an inch long; the crura are likewise of the same
length, and arising from the internal face of  the crura  of the
pubes, unite beneath the  symphysis so  as to  form  the body.
The body  is not straight, but has the  anterior  half bent down-
wards and forwards.  The exterior covering, or capsule of the
clitoris, in its texture,  resembles the elastic ligamentous mem-
brane of the corpus  cavernosum penis;  and is, moreover, filled
within by a  similar cavernous or cellular  structure, which  is
divided into two equal parts by a septum pectiniforme, and  is 
108            FEMALE ORGANS OF GENERATION.

susceptible of distention during sexual excitement.  The clitoris
is supplied also with blood vessels and  nerves like the penis,
and is held up to the under part  of the symphysis pubis by a
suspensory ligament.
  The anterior extremity of the body of the clitoris is found in
the rima or fissura vulvas, about an inch below the upper com-
missure of the labia externa.  It projects somewhat, and bears
a general resemblance in shape with the end of the penis,
whence its name of glans clitoridis; but it has not the same or-
ganization, excepting the delicacy, the extreme sensibility, and
the vascularity of the skin which covers it.  The clitoris has no
corpus spongiosum, neither is it  concerned, like  the penis, in
conveying the urine from the bladder.  Its glans is covered by
a doubling of skin called the prepuce, and is likewise furnished
with the glandula? Tysoni, from which is discharged a smegna,
or sebaceous fluid, as in the male.  The prepuce  does not fur-
nish a regular well defined frasnum.
  The Erector Clitoridis muscle corresponds with the  erector
penis.   It arises from the ascending ramus of the ischium, and,
covering the inferior face of the crus clitoridis, runs as  far for-
wards as the commencement of the body.

  The Labia Interna, or Nymphas, are two duplicatures of the
mucous membrane of the vulva, which pass down, one on each
side, from the clitoris.   The prepuce of the latter terminates,
on either side, in  the labia; while the latter are continued up-
wards, by a narrow process, to the under surface of the glans
clitoridis. They arise all along their base, from the internal sides
of the labia externa, or majora; and  being wider  in the middle
than elsewhere, they terminate insensibly about half-way down
the orifice of the  vagina.   Between  the laminas of each one is
placed  a vascular cellular substance, susceptible of distention
and of partial  erection during  sexual  excitement.   In young
subjects,  their  vascularity communicates  a vermilion tinge,
which is  lost and becomes brownish in the progress  of life.
As  they are effaced during parturition, their chief use seems to
be  as a provision for  the great distention of the vulva, which
then occurs.
  The labia interna are about half an inch broad in the natural
state, and do not  project obviously beyond the labia externa, 
THE VULVA.
109
except in cases of extreme emaciation, where the prominence
of the latter has been destroyed by a removal of its fat.   They
are, however, very subject, as the individual becomes old, to a
pointed elongation, increasing their breadth to an inch, or  an
inch and  a half; and to become thickened and  indurated.  A
tribe of Hottentots, the  Boschisnaans, living near  the Cape of
Good Hope,  are  uniformly subject to this enlargement;  which,
for a long time, was represented, by travellers, as an organ
superadded to what is common in the human species.

   The Vestibulum  is a depression of twelve  or fifteen lines
long between  the labia  interna; it is bounded  above by the cli-
toris, and below  by the  orifice of  the vagina.  It is abundantly
furnished with mucous lacunas.

   The Urethra of the female has its external orifice (Orificium
Urethra) in  the  inferior part of the vestibulum, about one inch
below the glans clitoridis, and is generally marked by  a slight
rising, which is  easily distinguished by  the sensation of touch
alone; its margin is often  bounded  by a  little  caruncle  on each
side.*  The  urethra itself  is an inch long, larger and much more
dilatable  than  that of the male, its course  is obliquely down-
wards and forwards from the neck of the  bladder; passing under
the symphysis of the pubes, and being slightly curved from that
cause.  It consists of  two  membranes, a  lining and an external
one.  The  lining membrane  is a  continuation  of that of  the
 bladder;  it is thrown into  several  longitudinal folds, and  has
 many mucous follicles in  it.   The  external coat of the  urethra
 consists of condensed laminated  cellular membrane, having  a
strong affinity with  muscular fibre: the principal  direction of
the fibres is  transverse, forming  a  cylindrical  body of half an
inch in its transverse diameter, and which has given the idea of
the existence of a prostate  gland in the  female: the lower and
lateral surfaces of this cylinder are  in contact with the vagina,
forming a protuberance  into its cavity; and  the upper surface is
firmly connected to the triangular ligament of the pubes.  Im-
 mediately behind the neck of the bladder,  we find the vesical
   * Doct.  Pancoast considers  the urethra of the young female to have its orifice
on a level with the anterior face  of the Symph. Pubis, whereas, in such as have
borne many children it is behind the pubes.  Wistar's Anat. vol. ii. p.  182, Phil
1839.
   Vol. II.—11 
  110            FEMALE ORGANS OF GENERATION.

  triangle with its muscle, as in the male, excepting that the an-
  terior angle of it goes to the anterior end of the urethra.
                                              «
    The  Fossa  Navicularis  is  that portion of the  rima vulvas
  which is below the vestibulum, and anterior to the orifice of
  the vagina.

                   SECT. II.--OF THE VAGINA.

    The Vagina is a thin membranous canal which leads from the
  vulva to the uterus.  It is from four to six inches in length, dif-
  fering according to age and pregnancy, and  being much shorter
  in women who have borne children than in virgins.  It is placed
  between the  bladder in front, and the  rectum behind, being
  flattened by them  so as  to bring  its anterior and  posterior sur-
  faces into contact.   Its  anterior extremity is the smallest of the
  two; and presents  its greatest diameter vertically, while that of
  the posterior is transverse.   As it follows accurately the central
  line of the pelvis,  it is, consequently,  curved with its concavity
 forwards.  Its anterior  parietes are shorter  than the posterior,
 both from the smaller depth of the pelvis in this direction, and
 from the mode of connexion with the  uterus.
   The vagina is formed  by two tunics; a fibrous and  a mucous
 one.  The first is external, of a light red colour, highly elastic,
 and seems to consist of condensed cellular membrane, the fibres
 of which are much  intermixed, and pass in every direction.  It
 is vascular, and immediately adjacent to the large venous sinuses
 of the pelvis.   The mucous membrane being  a continuation of
 that of the vulva, is at and near  its anterior orifice  of a vermi-
 lion tinge; while, posteriorly, it  is grayish and frequently spotted,
 so as to give it a marbled appearance: its thickness diminishes as
 it recedes  from the external orifice; and upon being floated in
 water many mucous lacunas are observable upon it.
   The internal surface of the vagina is commonly covered with
 the  mucus which comes  from  its  lacunas.  On the  anterior or
 pubic portion, it is divided longitudinally by  a  middle ridge,
 which  commences  by a  sort of tubercle just below the orifice
of the urethra, and  proceeds backwards, becoming indistinct as
it approaches the uterus.   Transverse ridges formed in  the same
way by folds of  the mucous membrane, arise from the sides of 
THE VAGINA.
Ill
the last at its anterior portion, and give a roughness  to that part
of the vagina.   The inferior side, or that next to the rectum,
has the same kind of arrangement of the mucous membrane, but
not so  distinct.  In a majority of  subjects, the uterine half of
the vagina is perfectly smooth,  but  the rule does  not always
hold.

   The Corpus Spongiosum Vaginas is an erectile tissue, like that
of the  penis, and closely resembles in  structure  the corpus
spongiosum urethras.  It is placed at the anterior end of the va-
gina, on its outer circumference, just below the clitoris, and at
the  base of the labia minora or interna.  It is  an inch broad,
and a line or two thick, adheres closely to the  fibrous coat of the
 vagina, and extends around  the superior  semi-circumference of
 the orifice, but not around the anterior. It is frequently called
 Plexus Retiformis.
   The Sphincter Vaginas Muscle surrounds the anterior orifice
of the vagina,  and covers the plexus retiformis.  It is about an
 inch and a quarter wide, and  arising from the  body of the cli-
 toris and the crus of the pubis, behind the crus of the clitoris,
passes backwards and downwards to be inserted into the dense,
 white substance, in the centre of the perineum, common to these
 muscles, the tranversi  perinei  and  the anterior point of the
 sphincter ani.   There is a  strong analogy between it  and the
 accelerator urinas of the male.

   The Transversus Perinei  of the  female, has the same circum-
 stances of origin and insertion as in  the male, but is not quite so
 strong.

   On each side of  the orifice of the vagina,  near its middle, is
 frequently found a mucous  gland, the size of a garden pea:. it
 corresponds with Couper's gland of the male subject.

   The Hymen,* one of the attributes of the virgin  state, is
 placed at the  anterior orifice of the vagina for the purpose of
 closing it, and  commonly remains  until  it is ruptured "by vio-
 lence.   In all  cases, except where there is an unnatural adhe-

   *  J. G. Tolber, Diss, de Variet.  Hymen.   Haller, Icon.  Anat. Fasc. i. Albin.
 Acad. Annot. Lib. iv.  Santorini, Septemd. Tab. 
112
FEMALE ORGANS OF GENERATION.
sion, it leaves a small orifice for the passage of mucus  and of
menstrual blood.   In my own observations, I have found it most
frequently crescentic, the  convexity of the crescent presenting
downwards, and the horns upwards;  but in some cases, it is to
one side.  Next in frequency to the lunated is the circular shape,
where it surrounds completely the  orifice  and leaves a hole in
its own centre.   There are some other varieties, such as its be-
ing fleshy, fasciculated, unequally divided into two portions, and
so on,  which  are narrated by different writers.   Being simply
a duplicature of the mucous  membrane, it is generally so  weak
as to  be ruptured at the first act of copulation,  or  even from
slighter causes  during  infancy;  but  occasionally, it becomes
thickened, and  so  strong as  to require division with  the  knife.
After the rupture of the hymen, its place is indicated in subse-
quent life by from two to  six small tubercles, called Carunculas
Myrtiformes, which are its remains.
   The peritoneum, in  descending from the uterus, anteriorly,
touches the top of the vagina  for a little distance, and is then
reflected to the bladder, but  posteriorly, almost the upper half
of the vagina has a peritoneal coat before this membrane  is re-
flected to the rectum.  The attachment of the vagina to  the
bladder is strong and close just above the urethra, but its con-
nexion with the rectum is by rather loose cellular  substance.


         SECT. III.—OF THE UTERUS, AND ITS APPENDAGES.

   The Uterus,  or Womb, is a compressed  pyriform  body, the
larger end of which stands upwards, while the lower is directed
downwards, and  is attached to the vagina.*  Unimpregnated,
  * This is commonly represented by anatomists in their plates and descriptions
as the position of the womb ; it is, however, more so in advanced pregnancy
than when empty.  In my dissections generally, I have found the posterior  face
of the womb downwards, reposing upon the concavity of the rectum, and the os
tincse obliquely forwards; this position being probably produced by the super-
incumbence of the small intestines,  and, especially, when the bladder is  empty.
When the latter is full, the peritoneum is reflected from the centre of the ute-
rus to the posterior face of the bladder, and its traction has the effect of erect-
ing the uterus in part, from its nearly horizontal direction.  In a dissection of a
female,  April 9, 1838, aged eighteen, who died from an affection of the brain,
there being every evidence of soundness in the genital organs, I found the rec-
tum making a curve to the right side of the inferior part of the sacrum, and the
body of the womb,  reposing in the concavity of the latter, 
UTERUS, AND ITS APPENDAGES.
113
it is two and a half inches long, and one and a half in diameter
at its widest part.   The  posterior face is very convex, while
the anterior is almost flat, or very slightly convex.   It is about'
one inch in thickness.   It is divided by anatomists into fundus,
body, and neck.   The  fundus is formed  by its superior extre-
mity, and comprises  the space  between  the orifices of the
Fallopian tubes:  the neck is  the  lower cylindrical portion, of
about an inch in length; and the body is  the part intermediate
to the two.   On the exterior circumference of the uterus there
are no marks or lines distinguishing these several portions from
each other.
   The uterus, being destined  to lodge  the foetus from a short
period after  conception to  the  moment of  birth, has a  cavity
ready for its reception.   The shape of  this  cavity  bears some
general, but not a rigid resemblance to that of the organ itself,
and it is so much flattened as  to have its anterior and posterior
parietes in contact, or nearly so.  The  cavity of the body is an
equilateral triangle of eight or ten lines in diameter; the sides
of the triangle are bent inwards in parabolic curves, in such  a
way as to present their  convexities to the cavity of the uterus :
this, of course, occasions an apparent elongation of the angles.
The inferior angle  is  continued  into the cavity of the neck,
while the two superior  run  into their  respective Fallopian
tubes.   From this arrangement it happens  that the parietes of
the uterus are only three lines thick on  the angles of the trian-
gular cavity, while at the middle they are from four  to six lines.
The cavity of the neck has not its anterior  and posterior sides
so near together as that of the body; and is rather cylindrical,
being smaller,  however, at  the upper and  lower ends than in
the middle.   This arrangement gives to its  sides a paraboloid
curvature which  presents its  convexity outwards,  differing in
that respect  from the corresponding curvature in the cavity of
the body.
  The cavity of the neck terminates in the vagina by an orifice
about the size  of a  small writing-quill, but  ovoidal, and pre-
senting its long diameter transversely.  This orifice  is the Os
Tineas, or Orificium Externum Uteri; frequently, without  ap-
parent disease, I have seen it conoidal, with its base, half an inch
in diameter, presenting downwards.  The upper orifice, where-
                            11* 
114
FEMALE ORGANS OF GENERATION.
 by the cavity of the neck communicates with that of the body
 is not subject to such fluctuations in size: it is occasionally called
 Orificium  Internum Uteri, and  is generally somewhat  larger
 than a small writing-quill.  The os tineas is bounded before and
 behind by  the lips of the uterus, formed  by the  projection of
 the neck into the vagina.  For the most  part  the anterior lip
 is directly continuous with the anterior side of the vagina; so
 that its projection is very inconsiderable, and, indeed, not ap-
 preciable to the finger: at the  same time, this lip is rather thicker
 than the posterior. The projection of the latter, on the contrary,
 is  always  well marked, because the vagina, instead of being
 inserted into its ridge, is pined to the posterior surface of its
 base.
   The cavity of  the uterus is lined by a very thin mucous mem-
 brane, a continuation of that  of the vagina.   This membrane is
 of a light pink colour, which  changes to a vermilion during the
 period of menstruation;  it  is  said to  be furnished with villosi-
 ties, which, though seen with difficulty in the usual way, may
 be rendered apparent, by floating the uterus in water; and it ad-
 heres so closely to the substance  of the uterus, that it forms an
 inseparable portion of it, which can neither be dissected nor ma-
 cerated off entirely, as in the  case of other mucous membranes.
   This membrane is smoothly laid upon the  cavity of the body,
 and gives it a polished shining surface.  On the cavity of the
 neck, it is  wrinkled  along the anterior and the  posterior parts;
 there being a longitudinal line running along the centre, and on
 each side of this line transverse  or oblique elevations or dupli-
 catures. This arrangement presents an arborescent appearance,
 technically called the arbor  vitas.  In the. interstices of these
 duplicatures there are some  small  mucous  glands or lacunas,
 which, as their orifices are exposed to obliteration from inflam-
 mation  or  some  other irritation, become distended  into  small
 spherical sacs by the accumulation of their  habitual  secretion.
Naboth, from seeing them in  this  state, mistook them for eggs,
or the rudiments of the foetus, and the error has been comme-
 morated by their  being called Ovula Nabothi.

  The  uterus is covered  completely by the peritoneum; in the
reflection of the latter, from the  rectum to the  bladder, it ad- 
UTERUS, AND ITS APPENDAGES.
115
heres to the uterus by a subjacent cellular substance, which al-
lows it to be dissected off without difficulty.   The same dupli-
cature of peritoneum which encloses the uterus, is also reflected
from each of its  lateral margins, by their whole length  to the
corresponding side of the lesser pelvis, and forms the Lateral
or the Broad Ligament, (Ligamenta Lateralia, Lata.)   The pe-
ritoneum, in passing from the uterus forwards to  the bladder,
forms, on each side, a duplicature, not very  distinct, and de-
pending, in a measure, upon'""the state of the bladder; this con-
stitutes the  Anterior Ligament.   The same  membrane, in
passing from the back of  the  uterus to the rectum, and in co-
vering the posterior superior end o*f the vagina, also forms, on
each side, a  duplicature, denominated the Posterior Ligament;
they are always better seen than the anterior.   Muscular fibres
are said to be found, occasionally, between the laminas of these
several duplicatures, running in the direction of the  latter:*
they have not been presented  to me  in such a  way as to arrest
my attention.
   The broad ligaments, along with the uterus, form a transverse
septum, passing from one  side of the pelvis to the  other; and
contain, between their laminas, the arteries and the veins which
belong to  the uterus and ovaries.
   Besides the duplicatures of peritoneum, the uterus is retained
in its position by the Ligamenta  Rotunda, one on each side.
These  round ligaments arise from the sides of the uterus, a lit-
tle below the insertion of the Fallopian Tubes, and going between
the laminse of the broad  ligament, reach, finally, the  internal
abdominal ring: they then  traverse the abdominal canal and the
external ring after the manner precisely of the  spermatic chord,
and terminate by several fasciculi in  the fatty cellular matter of
the mons veneris and of the labia  majora.   The round ligaments
are rather smaller in the middle than at either extremity; they
consist of a condensed cellular or fibrous structure, and have
many blood vessels in them.  It has  been  asserted,f  that they
contain strongly marked muscular fibres; some of which come
from the uterus, and others from the  broad muscles of the abdo-
men.   No evidence of this fact has as yet been  presented to me,

    * J. F.  Meckel, vol. ii. p. 605.           f J. F. Meckel, loc. cit. 
116
FEMALE ORGANS OF GENERATION.
though I do hot deny it;  and, indeed, I  think  it probable, that
such fibres may be developed there during gestation.

  The texture of the uterus is very compact, and  of a cartila-
ginous feel; it is  composed of  fibrous matter, intermixed with
a great many blood vessels.  In regard  to its fibrous structure,
there is no subject in anatomy on which opinions  are more di-
vided, or more authoritative and  numerous on both  sides of
the question.  Some deny its existence at  any period, while
others admit it as a constant condition: others, again, limit its
duration only to the period of pregnancy.  Without  dwelling
on the value of the several doctrines, and the means and obser-
vations  tending to support them, it may be sufficient here to
mention that the  structure of the  uterus takes on very impor-
tant and strongly marked changes, in passing from the unim-
pregnated state to that of advanced gestation.   In the first the
fibres look ligamentous and pass in every direction, but so as to
permit the uterus to be  lacerated  more readily from the  cir-
cumference to  the centre than in any other course: it, indeed,
manifests an indisposition  to be torn in a  laminated manner.
The fibres, moreover, break off short, are separated by the blood
vessels, and seem to contain, in  their interstices, something like
fibrine.
  In the impregnated state, on the  contrary, the vessels become
immensely increased in size, the laminated  structure  becomes
very evident, and submits readily to the tearing of one layer
from the other: these lamina  consist of fibres, which  are princi-
pally  parallel with each other.   The muscular nature of these
fibres seems to be sufficiently  proved,  by their powerful con-
traction in the expulsion  of the  foetus, and on being irritated by
the introduction of the hand.  They are, however, not red like
other muscles, but of a very light colour  as those of the bladder
and intestines; and are collected into fasciculi of peculiar flatness
and looseness.  The development of this muscular structure  is
not, however, limited to the pregnant state, but it is disposed to
manifest itself on  all occasions which produce  an increased size
in the uterus.  This fact was first exemplified  to me in a small
scirrhus of a virgin uterus, presented by Dr. Hugh L. Hodge,*

      * Now Professor of Midwifery in the University of Pennsylvania. 
UTERUS, AND ITS APPENDAGES.
117
and has been still farther confirmed in a case, where the scirrhus
was five or six inches in diameter; also in a virgin uterus, very
much enlarged  from scirrhus, presented  by Dr. Charles  D.
Meigs.  A similar fact has been noticed by Lobstein, of Stras-
burg, where the tumour was also steatomatous.

  The fibres of the uterus, examined near the term of pregnan-
cy, consists in two planes separated  by the large blood vessels;
one within and  the  other without.   These layers are readily
divisible into subordinate laminas, intermixed with one another
but yet to a considerable extent separable.  The external layer
is thicker than the internal, and both have an increased thick-
ness  at the fundus: while they are much diminished, and in-
deed  indistinct, at the cervix.
  The  fibres  generally are  either circular or longitudinal, but
many of them are oblique.   The exterior surface of the exter-
nal plane, is composed principally of longitudinal fibres, within
which are the circular.  The inner plane, on the contrary, has
the circular fibres external, and  the longitudinal internal.   In
both  planes the circular fibres are more abundant at the fundus,
and the longitudinal upon the body of the uterus; but, generally
speaking, there are collectively more longitudinal than circular
fibres.


                   Of the Fallopian  Tubes.

   The Fallopian tubes (Tubce Failopiance) are two membranous
canals, one on either side, fixed in  the superior margin of the
broad ligaments of the uterus.  They serve  to conduct  the ru-
diments of the embryo from the ovarium into the uterus.  They
are about four inches long,  and extend from  the  upper angle of
the uterine cavity to the  side  of the pelvis: their outer extre-
mity is loose, and hangs upon the posterior face of the broad
ligament  over the  ovarium, consequently  inclines downwards,
thereby forming an  angle with the other portion.
   At their uterine extremities the Fallopian tubes are about the
size of the vas deferens, resemble it  strongly, and scarcely ad-
mit  a hog's  bristle; but having  proceeded about one-half of
their length, they begin to enlarge, and continue to do so rapidly 
118
FEMALE ORGANS OF GENERATION.
for  an inch, until they reach the size of a writing-quill; they
then contract again somewhat, and immediately afterwards ex-
pand into  a broad  trumpet-shaped mouth.  The latter has an
oblique  orifice, the edge of which is extremely irregular, by
being resolved  into a number of ragged fringe-like processes,
of unequal size and length; and which,  as a whole, are called
Corpus  Fimbriatum, or Morsus Diaboli.  One of the longest
of these processes adheres to the external end of  the  ova-
rium.
  The Fallopian tube is  covered by the peritoneum,  and con-
sists of two coats:  the external is fibrous, and bears  sufficient
resemblance to the structure of the uterus to be considered a
continuation of it; the internal is mucous, and is likewise a con-
tinuation of the corresponding one of the uterus.  The external
end of the tube, which is called Pavilion by the French anato-
mists, is flaccid, thin, and generally in a collapsed state, as it is
formed solely by the mucous membrane, assisted by the perito-
neum, either of which furnishes resistance sufficient to keep it
expanded; but, as many blood vessels enter into its composition,
their turgescence, in sexual excitement, probably communicates
a certain degree of erection.


                      Of the Ovaries.

  The Ovaries, (Ovaria,  Testes Muliebres,) two in number, one
on either side, are situated on the posterior face of the broad li-
gaments by a duplicature of which they are  surrounded, and
are twelve or fifteen lines below the Fallopian tubes.   Their
shape is that of a compressed ovoid, about  half the size of the
male  testicle: their long diameter is horizontal;  they are sus-
pended from the broad ligament rather by the edge thanl)y the
flat surface, so that they- project, and are to a considerable de-
gree pendulous.  Their distance from the uterus varies from an
inch to an inch and a half, and from the internal end of each one
there proceeds a small vascular fibrous chord, the Ligament of
the Ovarium, which is inserted into the uterus, somewhat  below
the origin of the Fallopian  tube.
  From their being the  seat of conception, they have, in the
youthful and healthy female, a pliancy and succulency, indica- 
THE OVARIES.
119
live of their state of preparation for the  act; but  in advanced
life they diminish much in volume and become hard and dry.
Their surface, originally smooth or slightly embossed,  is sub-
sequently rendered uneven,  by repeated acts of conception,
leaving on  it a  number  of cicatrices  or  small  stellated fis-
sures.
   They are of a light pink colour.  Within the peritoneal coat
is another, the Tunica Albuginea,  of a strong, compact, fibrous
texture, like the same coat of the testicle, and sending  inwards
many processes.
   The structure of the ovarium is not ascertained with entire
satisfaction,  though the grosser arrangement  of  it is  known.
But few females,  of  such  as are  presented in our dissecting
rooms,  have these parts in a state  fit for study, owing  to age,
disease, or excessive  sexual indulgence: my best  opportunities
have been derived from post mortem examinations, in private,
of individuals of from fourteen to twenty, where the virgin state
had been preserved.  When an ovarium of the latter kind can
be got, by cutting through the tunica albuginea simply, and then
tearing open the organ, it will be found to consist  of a  spongy
tissue, abundantly furnished with blood vessels from the sperm-
atic artery and vein.   In this spongy tissue are from fifteen to
twenty  spherical vesicles, (Ovula  Graafiana,)  varying in size
from half a line to three lines in diameter; the larger ones are
nearer the surface, and, from having caused the absorption of
the tunica albuginea,  may sometimes be  seen through the peri-
toneal coat, and  give to  the surface  of the ovarium  its em-
bossed condition.  The vesicles contain a transparent fluid sup-
posed to be, or to have within it, the rudiments of the embryo.
As the vesicles are evolved  they  advance from the centre to
the circumference.  Their parietes  are  thin, transparent, and
have creeping through them minute arterial and venous ramifi-
cations.*

   The Organs of Generation in the female are  supplied with
blood principally from the internal pudic and other branches of

  * In an ovary exhibited to me by Dr. Hopkinson, there were thirty-six ve-
sides. 
120             FEMALE ORGANS OF GENERATION.
the hypogastric  artery: their veins  run into the hypogastric.
Their nerves come from  the sacral  and from the  hypogastric
plexus.

  The Bladder and the Rectum, with  unimportant exceptions,
are the same in both  sexes.  The Levator Ani,  the Coccygeus,
and the Sphincter Ani, are also similar.  The pelvic aponeuro-
sis in the female, besides connecting  the bladder to the sides of
the pelvis, is attached to the anterior part of the vagina.  The
triangular ligament of the urethra also exists, but under circum-
stances somewhat modified by the close connexion of the urethra
with the vagina.
                     CHAPTER III.


         OF THE LACTIFEROUS GLANDS, OR BREASTS.

   The Breasts (Mammce)  of the  female are intended for the
secretion of milk,  and thereby to maintain  the  connexion be-
tween mother and  infant for some time after the uterine life of
the latter is passed.   All  mammiferous animals  exercise  this
function: in birds  there is a sort of  substitute for it, in the
changes which take place in the first  stomach  or crop during
incubation.   In the male subject, there is, also, a  small gland-
ular body on each  side, which has the same organization as in
the female, but  is  in  miniature, and always remains in a  col-
lapsed state, with some rare exceptions, when it has been known
to expand in volume, and to  furnish a  secretion, as in the fe-
male.*

  • In a male patient,  a resident in the Philadelphia Alms House, the pheno-
menon of a full evolution of the glandular structure in both breasts is manifested.
The individual (James  Mclntyre)  is forty-five years of age? the breasts are as
large as those of a nursing woman; but the nipples are not proportionately evolved.
Though his frame is robust, and well set, the voice is feminine; his external or-
gans of generation are about the size of those of a boy of fourteen or fifteen. 
LACTIFEROUS GLANDS.
121
  The Breasts are two in number, one on either side; they are
situated on the same level, in front of the pectoralis major mus-
cle, and between the arm-pit  and  the sternum.   They are he-
mispherical, and have their base united to the muscle by a thin
lamina of loose, extensible, cellular substance, containing,  even
in corpulent women, but little fat.  The skin which covers the
front of this gland is very fine  and thin, so that the blood which
circulates in its veins may be  readily seen.   Between the skin
and the front surface of the gland, there is a considerable thick-
ness of cellular adipose matter, which, from its superabundance
in some individuals, gives to them an appearance of having
the glands enormously enlarged.   There is, however,  a great
variety in the  size of the glandular structure itself; for, in fe-
males who are youthful and giving suck, they are much larger
than in  such as have  passed  the period of child-bearing, and
whose health is impaired.  When all the fatty matler has been
removed from a breast, and  it is permitted to  repose upon a
table, its hemispherical  shape disappears,  and it then seems
rather a  flattened circular disk, of from four to five inches  in di-
ameter.
   The mamma is of a very light  pink colour; and though very
flaccid and yielding on being handled, its texture is actually ex-
tremely tough, and  is cut only by much force.    With the ex-
ception of bone,  it dulls  a knife  sooner than any other tissue
of the body.   Its grosser arrangement consists  in lobes of dif-
ferent sizes, united in such a way by cellular texture, that, though
they can be pulled somewhat apart, they cannot be entirely se-
parated  without injury.   These lobes, when examined through
the skin, ^ive  to the gland a  knotted feel,  and  are sometimes
partially affected by inflammation, so as- to become  still  more
distinct.   The Lobes are composed of Lobuli, which are resolva-
ble  by maceration and particular  modes  of  treatment, into
small o-i-aniform masses (acini) about  the  size of millet  seed,

Thinking that there might be an internal state approaching to hermaphrodism, he
informed me, on inquiring, that in earlier life he had the common inclinations for
the female. He also informed me that  this unusual development took place seven
or eiijht years ago, owing to an excessive salivation; but, as  he has a reserve on
the subject, this statement may, probably, be received with some qualifications. [
have also seen a second case, in which the voice is weak and feminine, but the ge-
nital organs have not been examined.— July, 1826.
   Vol. II.—12 
122                 LACTIFEROUS GLANDS.
 and which contain the ultimate glandular arrangement.  The
 acini themselves consist of very small  oblong vesicles, united
 by cellular substance, and by the common blood vessels; and are
 said  to be very apparent by the aid of a microscope in a lac-
 tescent gland.*
   Excretory Ducts (Duttus Galactophori,  Lactiferi) of this
 gland are numerous.f   They are of an arborescent shape, and
 becnn by very fine extremities or ramuscles in the acini; the ra-
 muscles from several acini coalesce into a larger branch;  seve-
 ral branches unite to form  one  still  larger, and  so on, succes-
 sively, until a lactiferous duct, constituting, as it were, the  body
 of  the tree, is formed  by this assemblage.  These trunks vary
 considerably  in size,  according  to  the number of  tributary
 branches, and having got towards the centre of the gland  near
 the nipple, from two to four of them, according to Cuboli,run into
 a  common stock or root, called a  Lactiferous Sinus.  These
 Sinuses are in all about fifteen:  they are only a few lines  long,
 and differ in  size; some not  being larger than a lactiferous  duct,
 while others  have a diameter of from two to three lines.   The
 sinus  at the end next to the nipple terminates in a sort of round-
 ed cul-de-sac; but from the  extremity of the sac a conoidal tube
 arises which  runs through the nipple, and conducts the milk: the
 point  of this tube is very fine, and ends on the top of the nipple.
 This  tube, from its shape,  is suited to the  retention of milk;
 in addition  to which, it is sometimes dilated in  the  middle, is
 curved when the nipple is not in a state of erection  or stretched
 out, and terminates by an external orifice," which is so small  as
 to be  seen with difficulty by the naked eye.

  The excretory ducts of the breast, under which term may  be
 comprehended, the lactiferous ducts, the sinuses,  and the conoi-
 dal tubes in the nipple, are formed by a soft, thin, and semi-trans-
 parent membrane, very capable  of extension and  of contraction.
 The trunks generally go deeply through the substance of the
gland, and are tortuous, but do  not anastomose laterally  With
one another;  whence it happens that the lobes and lobules  of

  *  Marjolin, Manual D'Anat.  J. F. Meckel, Manual D'Anat.
  ■j-  Alex. Kolpin, Diss Inaug. de Struct. Mam.  Cuboli, Append, ad Septemd.
Tub. Santorini,  Girardi, Append, ad Septemd. Tab. Sanlorini. 
AREOLA.
123
the gland are arranged into sections, each of which has its ap-
propriate excretory duct.  In order to make a complete injec-
tion of the gland, each sinus must be separately injected through
its conoidal tube.   This  rule is not, however, of universal ap-
plication, as in some experiments performed by the elder Meckel
upon womenadvanced in pregnancy and during lactation, he
succeeded  in forcing mercury through one sinus, by its ramifi-
cations, into those of another: this route was supposed to have
been through the finest extremities  of the ducts.  The whole
gland itself may, however, from the infrequency of this circum-
stance, and from the difficulties and partial condition of these
anastomoses, rather be considered as  a congeries  of  smaller
glands kept distinct by the interposition of cellular substance be-
tween theirjobes;  but joined, in one respect, by having the ter-
minations  of their  excretory tubes collected  into one bunch in
the nipple.   This latter circumstance seems to be only a provi-
sion for the more convenient sucking of the infant.
   The excretory ducts are no  where furnished with  valves,
which accounts for the facility with which they may be injected
backwards from the nipple.  An  opinion was  entertained by
Haller, and by other anatomists after him, that  some of these
ducts  originated in the surrounding cellular substance, but this
has been refuted by the researches of Cuboli.   Some anatomists
have thought that there is a direct communication between the
ends of the lactiferous tubes and the arteries, veins, and lym-
phatics. Mascagni, after a very success-ful injection of the gland,
whereby its vesicles were filled with quicksilver, not meeting
with such an occurrence, "was induced to think  that when the
communication did happen, it was produced by rupture.


                        The Areola,

   In virgins is a rose-coloured circle, which  surrounds the base
of the papilla or nipple.  In women  who have  borne children,
or in those  whose age is advanced, it becomes of a dark brown.
The skin of the areola is extremely delicate, and on its surface,
particularly in pregnant or nursing females there are from four
to ten tubercles, which sometimes form a regular circle near its
circumference, and in other subjects are irregularly distributed.
Each  of these tubercles has near its summit three or four fora- 
124
LACTIFEROUS GLANDS.
mina, which are the orifices of the excretory ducts of a little
gland forming the tubercle.  The areola consists of a spongy
tissue beneath which there is no fat;  it is susceptible of disten-
tion during lactation, or from particular excitement.

  The greater number of anatomists have considered these tu-
bercles as intended only for the secretion of an unctuous fluid
which lubricates the areola and nipple, and protects them from
excoriation by the sucking of the  infant.  It is said, however,*
that when some time has elapsed  after a repast, or when there
has been a long interval to the nursing of the child, milk flows
from  them abundantly;  but that in  inverse circumstances a
transparent, limpid fluid is distilled in small drops : all of which
would tend to prove that, they are of the  same nature with  the
mammas themselves, being only smaller.   In addition to them,
it is said, that the areola  and the nipple  are furnished with a
great number of sebaceous glands, which do not elevate them-
selves above the surface, and which may be found on and near
the tubercles.

                        The Papilla,

  Is the truncated cone in  the centre of the mamma, of the same
colour with the areola, and surrounded by it.  The lactiferous
tubes  terminate on its extremity.   It is collapsed and in a very
pliable state for the most part, but when excited  it swells, be-
comes more prominent, and of a deeper colour.   Its skin is
rough, and  provided with  numerous  and very small papillas.
Its internal structure consists of the extremities of the lactiferous
tubes  united by condensed cellular membrane.
  The mamma is supplied with blood from the external thoracic,
intercostal, and the internal mammary arteries. Its veins attend
their respective arteries.  The nerves come from the axillary
plexus and from the intercostals.   The lymphatics run into the
internal mammary, intercostal, and axillary trunks.
* J. F. Meckel 
BOOK  VII.
                Of the. Organs of Respiration.


  The Organs of Respiration  are the Larynx, the Trachea,
and the Lungs.
                     CHAPTER I.

                     OF THE LARYNX.

   The Larynx is an irregular cartilaginous tube that forms the
upper extremity of the windpipe.  It is situated immediately be-
iow the os hyoides and the root of the tongue, where it may be
felt readily through the integuments, and by its prominence con-
tributes to the outline of the neck.  Its position is such, that it is
bounded behind by the pharynx, which is interposed between it
and the vertebras of the  neck; and laterally by the primitive ca-
rotid arteries and the internal jugular veins.   It gives passage
to the air which is inhaled into the lungs or exhaled from them,
and also contributes  essentially to the production of  the voice.
Its special use, on the latter occasion, has induced some anato-
mists to give it a description apart from that of the other organs
of respiration; but as the function of voice  is subordinate to
that of respiration, I have preferred an  observance of its  most
natural and  local connexions.
  Five distinct cartilages  form the skeleton of this  structure:
                            12* 
126                ORGANS OF RESPIRATION.
 the os hyoides, which is common to it and to the root of the
 tongue, also contributes to its superior part, in a manner which
 will be presently mentioned.  The cartilages are one Thyroid,
 one Cricoid, one Epiglottis, and two Arytenoid.

   The Thyroid Cartilage (Cartilago Thyroidea) is  the largest of
 the five, and being placed about one inch below the os hyoides,
 produces  in the upper part of the neck  the prominence called
 Pomum Adami.  It consists in  two lateral  halves,  which  in
 most individuals are perfectly symmetrical, and are continuous
 with each other on  the middle line of the body.  These two
 sides form at their line of junction an angle projecting forwards,
 and resembling that of the canal or hydraulic gate: the superior
 part of the angle is more prominent than the inferior; particu-
 larly in the male subject.   The sides of this body lean outwards,
 by which its transverse diameter above is increased.
   The angle is terminated above by a deep notch, from which
 the superior margin begins to form a curvature, on either side,
 like the letter S;  the inferior margin is also somewhat curved,
 but to a smaller degree.   The posterior margin of each half is
 nearly straight, but  is elongated above, with the aid of the upper
 margin into a long  process, the Cornu Majus; and below  with
 the aid of the inferior margin, into another process not so long,
 Cornu Minus.  By the latter, the thyroid cartilage  is articulated
 by ligamentous fibres called the Lateral Crico-thyroid ligament,
 to the side of the cricoid cartilage, which thereby becomes the
 fulcrum of many of its motions.
   The internal surface of each half of the thyroid cartilage is
 flat; but the exterior surface is slightly marked by ihe sterno-
 thyroid and the thyreo-hyoid muscles.

   The Cricoid Cartilage (Cartilago Cricoidea) is placed below
 the thyroid, and  is ihe base of the  larynx.   It is an oval ring, of
 an unequal thickness and breadth.                               •
   Its inferior margin is nearly straight and  horizontal, and is
 connected to the first ring of the trachea ; it is also thinner than
 the superior: the latter is very oblique, and  rises from before
 backwards and upwards so abruptly, that the breadth of the cri*
 coid cartilage  behind becomes  three times as great as it is in
front, under the inferior margin of the thyroid cartilage.  The 
THE LARYNX.
127
superior margin has on each side, behind, a little head, or con-
vexity, which receives the base of the corresponding arytenoid
cartilage, and forms with it a ball and socket joint.
  The interior  surface of the cricoid cartilage is  smooth, and
covered by the lining membrane of the larynx.   Its exterior
surface is flattened behind on each side, by the posterior crico-
arytenoid muscles; it is marked also laterally by other mus-
cles, and by the inferior  cornu of the thyroid cartilage.
  The cricoid cartilage is embraced  by the inferior margin of
the thyroid, but in  such a way that a triangular interval is left
in front between the two cartilages.
   This interval is filled by a ligament adhering to its margins
called the Middle Crico-Thyroid, to distinguish it from  the li-
gamentous junction between the inferior cornua of the thyroid,
and the sides of the cricoid.   The middle ligament has  some
small apertures in it  for the passage of blood vessels and of
nerves.   It is the part commonly cut in the operation of laryn-
gotomy.

   The  Arytenoid  Cartilages  (Cartilagines  Arytcenoidece) re-
semble triangular pyramids  curved  backwards, and about six
lines long.  They are placed on the upper margin of the cri-
coid cartilage behind.  The anterior face of each is uneven,
and divided into two concavities; the  posterior  face forms  a
single cylindrical concavity; and the internal face, by which  it
approximates its fellow, is  nearly flat.  When joined together,
the two cartilages resemble the mouth or  spout of  a  pitcher,
from whence their name.   Their bases  are  hollowed into  a
small glenoid cavity, for articulating with the cricoid cartilage.
   A synovial capsule is reflected over the articulation, between
the arytenoid and the cricoid cartilage: this capsule is strength-
ened by  a few  scattered ligamentous fibres.

   The Epiglottis Cartilage (Epiglottis) is situated on  the pos-
terior face of the base of the os hyoides, being enclosed partially
by the two sides of the  thyroid cartilage.  Its general form  is
that of an oval disk; the upper margin of it is thin and rounded,
partially curled forwards, and  the lower part is elongated into
a  pedicle which adheres to the entering  angle of the thyroid
cartilage. 
128
ORGANS OF RESPIRATION.
   Its surfaces, though nearly flat, are not fully so; for, ante-
 riorly, it forms a cylindrical convexity, and posteriorly, a cy-
 lindrical concavity, from side  to side.   When  nicely  stripped
" of its covering, a number of very small foramina are seen to
 exist in  it, which are considered to give passage principally
 to the ducts of muciparous gland.s.   Its  connexions, aided by
 its natural elasticity, keep it  in a vertical attitude behind the
 base of the tongue; its rounded margin is elevated above the
 latter,  and overlooks it,

   In addition to the preceding'cartilages, there are always two,
 and sometimes four others.  On the top of each arytenoid is to
 be found one,  (Corniculum Laryngis:) it is somewhat triangu-
 lar and elongated: its inferior face is attached  by  a few liga-
 mentous fibres to the end of the arytenoid; it is included in the
 soft parts, and is very moveable.   The others, when they exist,
 which is rare, are found on the margin  of the glottis, in the
 duplicature of the membrane which is  extended from the side
 of the  epiglottis to the tip of the arytenoid cartilage.

   From the whole superior margin of the thyroid cartilage in-
 cluded between its greater cornua, there proceeds  upwards' a
 thin lamina of somewhat condensed cellular substance, which
 is attached to  the inner margin of the base and  of the cornua
 of the os hyoides their whole  length.  It fills  completely the
 space between the os hyoides and the thyroid cartilage.   This
 membrane is called the middle Thyreo-hyoid Ligament, (Li-
 gament. Thyreo-Hyoid. Medium,) though  its  ligamentous  cha-
 racter is by no means well developed.   It completes  the pe-
 riphery of the  larynx in  the space alluded to, and, from its thin
 yielding nature, presents no obstacle to  the motions of the os
 hyoides and of the thyroid cartilage upon each other.
   The posterior margin of this membrane,  on each side, is
 bounded by a  long, rounded, fibrous chord, the Lateral Thy-
 reo-Hyoid Ligament, (Ligamentum Thyreo-Hyoideum Laterale.)
 The latter is extended from the cornu major of the  thyroid car-
 tilage to the tuberculated extremity  of the os hyoides, and fre-
 quently contains, about its centre, a small,  oval  cartilage or
 bone, (Cartilogo-Triticea,) not quite so  large  as  a grain of
 wheat. 
THE LARYNX.
129
   Immediately under the body of the os hyoides, between  its
 concave face and the middle thyreo-hyoid ligament, is a small
 sac  or cell formed between the  laminas of this ligament, and
 frequently extending itself downwards as far as the notch of the
 thyroid cartilage; it is flat about four  or five lines in its trans-
 verse  diameter, and presents a shining surface.  I have never
 seen a fluid in it  in the natural state; its secretion, however,
 sometimes becomes  excessive, and it  is then elongated down-
 wards over the front of the thyroid and of the cricoid cartilage,
 as far as the isthmus of the thyroid gland.  In this state it fre-
 quently forms a small fistulous opening, at its lower end, through
 the  skin, and which is  marked  by a  fold of the latter across
 the neck.  The true pathology of the  disease was first pointed
 out by the late Dr. Physick, who cured it, in some cases, by the
 introduction of lunar caustic, and in others by extirpation.

   The Thyreo-Arytenoid Ligaments  are two  in number,  on
 each side of the larynx  ; one above the other, at the distance
 of three lines.  The inferior is extended from  the anterior an-
 gle of the base of the arytenoid cartilage to the inferior part of
 the entering angle of the thyroid, and, by converging towards
 its  fellow, is  inserted there in  contact with it.   Its  fibrous
 structure is very distinct.  It also bears the name of Ligamen-
 tum Vocale, from its bordering the rima glottidis.  The supe-
 rior thyreo-arytenoid ligament arises  from  the middle of the
 anterior edge of the arytenoid cartilage, and  is also inserted
 into the entering angle  of the thyroid; it is more distant from
 its fellow than the lower one, and goes  almost parallel  with
 it; so  that  the  opening between the  two is  both larger and
 more like an oblong.  Its fibrous structure is less distinct  than
 that of the  lower.   Both the upper and the lower ligaments
 are covered by a reflection of the lining membrane of the la-
 rynx, and are  small, round fibrous threads, which are rendered
 more or less tense by the  action of the  small  muscles  of the
 larynx.
  The superior thyreo-arytenoid ligament is  attached, in its
whole  length,  by a triangular fibro-muscular layer to the pedi-
cle of  the epiglottis: the posterior margin of this layer is dis-
tinctly muscular, and must have the effect of drawing the liga-
ment upwards. 
130
ORGANS OF RESPIRATION.
  There are several pairs of muscles belonging to the larynx.

  1. The Thyreo-Hyoideus, as observed in the former account
of this  muscle,  looks  like a  continuation of  the sterno-thy-
roideus.  It arises, obliquely, from the side of the thyroid car-
tilage by the ridge, there; and running upwards, it is inserted
into a part  of the base, and into nearly all the cornu of the os
hyoides.
  When the  thyroid cartilage is fixed, it draws  down  the  os
hyoides; but when the latter is  fixed, it draws  up the thyroid
cartilage.

  2. The  Crico-Thyroideus arises,  tendinous and fleshy, from
the anterior lateral surface of the cricoid cartilage, and  passes
upwards and backwards, to be inserted into  the inferior cornu
of the  thyroid cartilage, and the  adjacent  part of its inferior
edge.
  Use, to draw these cartilages obliquely together.

  3. The Crico-Arytenoideus Posticus arises from  the back  of
the cricoid  cartilage, occupying its excavation, and is inserted
into the posterior part of the  base of the arytenoid cartilage.
  It draws the arytenoid backwards, and makes the ligaments
tense.

  4. The Crico-Arytenoideus Lateralis arises  from the  side of
the cricoid  cartilage, and is inserted into the side of the base of
the arytenoid.
  Use, to draw the  latter outwards, and open  the chink of the
glottis.

  5. The Thyreo-Arytenoideus  arises from  the posterior  face
of the thyroid cartilage, near  its angle, and the middle  crico-
thyroid  ligament, and is inserted into the anterior  edge  of the
arytenoid cartilage.
  Use, to relax the ligaments of the  glottis.

  6. The Arytenoideus Obliquus  arises from the  base of one
arytenoid cartilage,  and is inserted  into the tip of the  other. 
THE LARYNX.
131
It is  a very small fasciculus, and sometimes only one muscle
exists.
  Use, to close the chink of the glottis.

  7. The Arytenoideus Transversus is always a single muscle,
which arises posteriorly from  the whole length of  one aryte-
noid cartilage, excepting a little part of the tip,  and  is inserted,
in a corresponding manner, into the other.  It fills up the cylin-
drical concavity of the arytenoid  cartilages.
  Use, to close the chink of the glottis.

  8.  The  Thyreo-Epiglottideus  consists in a  few  fibres,  and
arises from the posterior -face of the thyroid cartilage near its
entering angle.   It is inserted into the side  of the epiglottis.
  Use, to draw the epiglottis downwards.

  9.  The Aryteno-Epiglottideus consists also in a few indistinct
fibres, and arises from the superior lateral  parts of the aryte-
noid cartilage.  It is inserted into the side of the epiglottis.
  Use, to draw the epiglottis downwards.
       »
  These two last muscles are generally so small and undefined,
that they cannot  be  satisfactorily distinguished  from the adja-
cent soft parts.

  On the posterior face of the thyroid cartilage, of the middle
thyreo-hyoid ligament; and on each side  of the epiglottis carti-
lage, surrounding its lower  part with the exception of its poste-
rior face, there is an accumulation of cellular and adipose sub-
stance.   In the lower part  of this substance there  are several
small glandular bodies, sometimes insulated and  sometimes  col-
lected together, which detach their prolongations into the fora-
mina of the epiglottis cartilage, and seem  to open  thereby on
its  laryngeal surface; they  are mucous glands.

  The Arytenoid Gland, which is  also muciparous, is situated in
front of the arytenoid cartilage, in the duplicature  of the  mu-
cous  membrane  which passes from the side of the  epiglottis
cartilage to the arytenoid.  It is a small  body of a grayish co- 
132
ORGANS OF RESPIRATION.
lour, resembling the letter L, and consists in distinct grains; it
is supposed to have its excretory ducts opening into the larynx.
It is frequently wanting.

  The Interior Face of the Larynx is lined by a mucous mem-
brane, continuous above with that of the mouth and pharynx,
and below with that of the  trachea.   Where it is reflected from
the base of the tongue to  the  epiglottis cartilage, it forms, as
described,  a  well-marked vertical  fold or frasnum  in  front of
the middle of the  latter, and on each side of this  middle fold
there is another, not  so distinct, but varying in  different sub-
jects.  Beneath  the  middle fold is  the strong fibro-muscular
connexion with the foot of the tongue.*  The three folds form
two pouches in front  of the epiglottis,  in which  food is some-
times lodged.  The mucous membrane  also forms  the duplica-
ture on each side already alluded to, which passes from the la-
teral part of the epiglottis cartilage to  the arytenoid  of  the
same  side of the body.  This  duplicature forms the  superior
boundary of the cavity of  the larynx, and  is very soft  and ex-
tensible, permitting freely the epiglottis to  be depressed  and to
rise again  into  its vertical position.  The duplications  of  the
two sides, taken  together, form an oblong oval opening into  the
larynx,  passing  very  obliquely upwards and forwards  to  the
epiglottis, and terminated  behind by a notch between  the cor-
nicula laryngis.   At the latter place the mucous  membrane is
wrinkled  and loose, so as to  permit, by its  extensibility, free
motion to the arytenoid cartilages.
   After adopting the  preceding arrangement, the lining mem-
brane of the larynx passes downwards; it  covers smoothly  the
posterior face of the epiglottis, adhering closely to it; but, when

  * A muscle of a triangular shape has lately been  observed  by the English
anatomists,! situated in front of the epiglottis, passing to it from the base of the
os hyoides: it is called llyo-Epiglottideus.   The observations on its existence
have not yet been repeated sufficiently often to determine whether it belongs to
the normal structure of the  body cr not; and in my own dissections, for the pur-
pose of assertaining its existence, it has not occurred,   Albinus, Soemmering,
and olhers, speak of the occasional existence of muscular fibres tliere.  A strong
muscle  is found there in the lower animals, as stated in the description of the
tongue, vol. 1st.
                     t Am. Med. Jour. vol. v. p. 475. 
THE LARYNX.
133
it reaches the thyreo-arytenoid ligaments, it is  tucked in be-
tween  the upper and the  lower one, so as to  form, on either
side, an oblong pouch, the bottom of which is broader than its
orifice between the ligaments.   This pouch is  the ventricle of
Galen, or of Morgagni, or of the larynx;  it projects into the
fatty glandular matter on the posterior face of the thyroid car-
tilage, and has its base resting on the thyreo-arytenoid muscle.
Its superior end  reaches almost as high as the upper margin of
the thyroid cartilage, and it has some small fasciculi of muscular
fibres on its belly which seem  appropriated to  its use.  The
continuation of  the membrane  afterwards lines  smoothly the
cricoid cartilage, and abounds there  in mucous follicles.
  That portion  of the larynx which is formed by the  thyreo-
arytenoid ligaments, and  the  pouches between  them, is  the
structure essential to the formation of voice.   The opening be-
tween  the two lower ligaments is the Rima Glottidis,  and the
space between the upper ligaments and the duplicature of the
mucous membrane passing from the arytenoids to the epiglottis
cartilage, may be termed the Glottis.
  The Epiglottis. Cartilage is  principally  useful  in preventing
articles of food  from falling into the glottis, either in swallow-
ing or in vomiting.   The strength of its muscles, however, does
not seem to be  sufficient  to draw it down over  the glottis, as
many physiologists suppose; on the contrary, I am induced to
believe that the glottis is  rather drawn upwards to it.  If, on
any occasion, it be depressed or bent down over  the glottis, the
position must  be caused by mechanical pressure  from the bulk
of the article swallowed.  But the latter explanation is  not suf-
ficient to account for the swallowing of fluids, or of a very small
body as a pill or a crumb of bread.
   Impressed  with these objections, and  unsatisfied with the
common theory, I had an opportunity, in a dissection a few
years ago, of witnessing a  position of these parts which afforded
a satisfactory explanation.  The subject was a robust, muscular
man, who had died suddenly.   The upper orifice of the glottis
was closed and protected, but by an  arrangement precisely the
reverse of the received opinion ; for  the epiglottis, retaining its
naturally erect position, with a slight inclination backwards, had
the opening of the glottis drawn up so as to come in  contact
with its posterior face.  The cricoid cartilage, as  has been men-
   Vol. II.—13 
134
ORGANS OF RESPIRATION.
tioned, slopes on its superior margin upwards and backwards*
the front surfaces of the arytenoid cartilages, in their natural
position, are nearly on a line with this slope, or a continuation
of it; the whole  may, therefore, be considered  in the light of
an oblique plane, rising up behind the epiglottis cartilage.   By
a very slight additional elevation of this plane along with the
rotatory motion of the thyroid cartilage upon its lesser cornua,
the plane is  caused to come in  contact with the posterior face
of the epiglottis, and thereby to close  the upper opening of the
glottis.
  The principal agents in this motion are the thyreo-hyoid mus-
cles, the contraction of which, causing the larynx to ascend, the
opening of the  glottis is brought  up behind  the  epiglottis, and
thereby secured from the introduction  of food into it.  Whether
the food be passed from the mouth  into the stomach,  as in
swallowing, or from the stomach into the mouth, as in vomiting,
is equally unimportant; and the security is the same, whether
the article be small or large, fluid or solid.  Several years ago,
I dissected a gentleman who had  symptoms of sore throat  with
swelling of  the neck, superadded to  those of pulmonary  con-
sumption: during the existence of  his sore  throat, in addition
to  the usual  difficulty of swallowing, he was  frequently affected
in the act, with strangulation to an alarming and distressing de-
gree.  In the dissection, it was found that an abscess, of  con
siderable extent, existed between the os hyoides and the thyroid
cartilage, and  involved the thyreo-hyoid muscles.   Without
knowing at the time the value of this observation,  I am now
persuaded that the strangulation arose from the inactivity of
the thyreo-hyoid muscles.  In some ulcerations of the epiglottis
cartilage, which I have had an opportunity of seeing, the up-
per circular  portion, which projects above the root of the tongue,
has been lost; if  the accident be confined to that extent only,
deglutition is not much impaired, because still  enough of the
epiglottis is  left to perform the office assigned to it,  as the up-
per part is less essential. The cases of its reputed loss by wounds,
must be considered as applying themselves to this upper portion
only, because a wound low enough to remove the whole body,
would  cause such a  destruction of  the rima  glottidis, as to
produce an embarrassment of respiration,  incompatible  with
life. 
THE TRACHEA.
135
  It is probable that the inferior constrictors of the pharynx, as
well as the stylo-pharyngeal muscles, assist in  this use of  the
thyreo-hyoidei.
  There is a well marked difference in the larynx of the two
sexes.   In the female, it is generally smaller by one-third than
it is in the male; the thyroid cartilage is also less prominent, in
consequence of its two halves uniting at an angle  more obtuse,
the pomum Adami is, therefore, seldom conspicuous. The rima
glottidis is also smaller in women.
  The nerves of the larynx come principally from  the superior
and the inferior laryngeal branches of the par vagum.
                    CHAPTER  IL

 OF THE TRACHEA, AND THE GLANDS BORDERING UPON IT

                   SECT. t.--THE TRACHEA.

  The Trachea, or Aspera Arteria,is a cylindrical canal of four
or five inches in length and about nine lines in diameter, com-
municating with the lungs  for the transmission of air.  It opens
into the larynx above, by  being attached to the inferior mar-
gin of the cricoid cartilage, and  terminates in the thorax oppo-
site the third dorsal vertebra, by two ramifications called Bron-
chia. In this course it is situated over the middle line of the
neck, beneath the  sterno-thyroid muscles, and separated from
them by the deep-seated fascia of the neck and the adipose mat-
ter beneath it.  It is placed in front of the oesophagus, between
the primitive carotid arteries and  the internal  jugular veins.
When it has got into the thorax, it inclines  slightly to the right
side as it passes behind the curvature  of the aorta.   Of its two
branches, the right bronchus is larger than the other; it is also
less  slanting, and an inch  long before  it divides;  it  sinks below
the right pulmonary artery, to  penetrate the lung  about  the
fourth dorsal vertebra.  The left bronchus being an inch longer
sinks into the lung  of the left side, below the corresponding 
13«
ORGANS OF RESPIRATION.
pulmonary artery, and opposite the fifth dorsal vertebra.  The
bronchia then divide and subdivide very minutely through the
lungs.
  Very dissimilar structures enter into the composition of the
trachea; they are cartilage, ligamentous fibre, muscle and a mu-
cous membrane.

  The Cartilage preserves the cylindrical shape of the trachea,
and consists in from sixteen to twenty distinct  rings, which are
deficient in the posterior third  of their circumference.  Each
ring is about two lines broad, and half a line thick, and is kept
apart from the one above  and  below it by a small interstice:
sometimes, however, they run into each other.  .
  There is an almost uniform similitude between these rings; the
principal departure from which is observed in the first being ra-
ther broader in front than the others, and in the  last ring, which,
by its corset-like shape in front, contributes to the beginning of
each bronchu .
  The rings of the Bronchia are, like those of the trachea, defi-
cient in their posterior third, and the same arrangement holds
during their primitive ramifications in the lungs.  But as they
subdivide more and more, the cartilages do not succeed each
other so closely, and are smaller segments of circles;  they also
are not regularly deficient at the posterior third; but, in place
of the  latter, the bronchial ramification is surrounded by car-
tilage, consisting in several pieces put end to end.   The pieces
become, after awhile, more and more scattered and smaller,
till  they finally disappear, and the bronchus  is simply mem-
branous.  At the orifice of each branch of the bronchia, there
is a semi-lunar cartilage, forming rather more  than one half of
its circumference, and having its concave edge upwards.  The
whole arrangement resembles somewhat the pasteboard to an
eared bonnet, and is evidently to keep  the orifice open.

  The Ligamentous Structure of the trachea and of the bron-
chia is very evident between the proximate margins of the car-
tilaginous  rings, and fills up the intervals between them so as to
make the tube perfect.  This tissue may be traced over the sur-
faces of the rings, forming their perichondrium, so that they may
be considered as imbedded in it.   It does not exist satisfactorily, 
THE TRACHEA.                       137
 in the human subject, in the  interval behind; where a  third  of
 the ring is defective, its place being supplied by  a condensed cel-
 lular substance; but in the bullock it is there also.  In the small-
 er ramifications  of the bronchia,  where a complete  circle  is
 formed  by the juxta-position of the several little  cartilaginous
 segments, it is probable that this tissue contributes to the whole
 periphery of the ramification.
   This  ligamentous structure possesses great elasticity, which
 is manifested by the rapid shortening of  the trachea, when its
 two extremities are stretched apart and then suddenly let loose.
 And it is the continuance of this quality of elasticity, in the mi-
 nute ramifications of the bronchia, which  proves the existence of
 this tissue there, even when it cannot be  very distinctly seen.

   The Muscular Structure  of the trachea exists  at  the cartilagi-
 nous deficiency in its posterior third, and  consists in a thin mus-
 cular plane whose fibres pass transversely  between the interrupt-
 ed extremities of  its  cartilaginous rings.  These  transverse
 fibres begin at the first ring, and exist  all  the way down: they
 arise from the internal faces of the rings, and the  intermediate
 elastic ligamentous tissue; about a line beyond their extremities.
 Anteriorly,  they are  covered by the lining membrane  of the
 trachea, and posteriorly, by the dense cellular tissue just spoken
 of.
   A  similar arrangement of  muscular  structure occurs  in  the
 bronchia and for some distance into the lungs.   Where the car-
 tilages become scattered and  irregular, the muscular fibres are
 said, by J.  F. Meckel, and by M. Reisseissen,*  to perform the
 whole circuit of the bronchial  ramification, and  to be  visible
 even beyond the  existence of the cartilaginous pieces.   Soem-
 mering expresses a doubt of this arrangement.!  It is very dif-

  * De Fabrica Pulmonis. Berlin, 1822. M. Laennecsays (Traite, de l'Ausculta-
 tion, Paris, 1826, vol. ii. p. 189,) that he has sought  in vain to verify these obser-
 vations of Reisseissen, but  that the  manifest existence of circular fibres upon
 branches of a middling size and the phenomena of many kinds of asthma, induce
 him to view, as a tiling well established, the temporary occlusion of the small
 bronchial ramifications, by a spasmodic contraction of their parietes.
  t Extimae autem vel posticac ejus fibrae per longitudinem, a cartilagine crrcoi-
dea ad pulmones usque descendunt ac, vel in ipsis  tracheae ramis baud paTum
conspicui sunt.—De Corp. Hum. Fabrica.
                              13* 
138                ORGANS OF RESPIRATION.
ficult in such minute structure to arrive at a  satisfactory con-
clusion; careful  observations, latterly made, have, however, in-
duced  me to adopt the same conviction as Reisseissen.  Longi-
tudinal muscular fibres are said  by Portal  to exist between the
contiguous margins of the cartilaginous rings, but the fact is far
from being ascertained.*

   The use of the muscular tissue has been pointed out, by the late
 Dr. Physicas follows:—"In expectoration,it diminishes the cali-
 ber of the air tubes, so that the air ha ving to pass out with increased
 rapidity through them, its momentum will bring up the inspissated
 fluid which may be in its way."   This very ingenious theory has
 subsequently been advanced by M. Cruveilheir, of Paris, possibly
 without a knowledge of his  having been anticipated; but  cer-
 tainly not without the claims of the eminent individual to whom
 we owe it, having  been established by its publication.^

   The Mucous Membrane of the trachea lines its whole  interior
 periphery, from the larynx to the bronchia, and is continued, un-
 der the  same circumstances, through  the latter to their minute
 divisions. It adheres very closely to the contiguous structure, and
 is continued, in the substance of the lungs, beyond the traces of
 any of the other tissues which  compose the trachea; it indeed
 terminates in the air cells.  It  is very vascular, like other mu-
 cous  membranes;  and also, like them, the venous appears to pre-
 vail over the arterial vascularity.  A successful minute injection
 makes it look as if it consisted  of a tissue of blood vessels; thin
 and red, it presents an abundance of slightly elevated longitudi-
 nal folds: one of the latter, conspicuous for its greater  size, ex-
 ists at the commencement of the left bronchus, and is yet more
 developed  in the still-born infant.

    The  exterior circumference of the mucous membrane is stud-
 ded with Muciparous Glands, about the size of millet seed. These
 glands  are particularly conspicuous and abundant  on  the pos-
 terior part of the trachea and  of  the bronchia, where  the defi-
 ciency of the cartilaginous rings is supplied by the membranous
 structure only; and more of them exist at the lower part of the

    * Anat. Med.  f Wistar's Anatomy, 3d edition, vol. ii. p. 64.  Phil. 1821. 
THE THYROID GLAND.
139
trachea and upon the  roots of the bronchia than elsewhere.
They are placed behind the muscular layer, which their excre-
tory ducts have to penetrate.  Besides occupying these situa-
tions, they are found in the interstices between the cartilagi-
nous  rings, but here  they are much  smaller.   The  mucous
membrane  abounds so much in the orifices made by their ex-
cretory ducts, that it looks cribriform, which appearance is in-
creased by floating it in water.
  About the origins of the bronchia, there is a considerable
number of black  coloured  lymphatic glands, called bronchial,
which it is easy to distinguish from the preceding by  their
colour and much greater size.

   There are two more glands of a different character, which,  »
though they do not enter into the  composition of the trachea,
yet, from their locality, are most  conveniently studied at this
time: they are  the Thyroid and the Thymus.


               SECT. II.--OF THE THYROID GLAND.

   The Thyroid Gland (Glandula  Thyroidea) is placed on the
first  and second  rings of the trachea, and on the sides of the
larynx.

   It consists in a middle portion which is thin, of variable mag-
nitude in different individuals, sometimes entirely wanting, and
 which, being stretched across the upper part of the trachea just
 below the  larynx, is called its isthmus: and of  two lobes, one
 on each side,  which, being flattened  and ovoidal, are extended
 considerably upwards on the side of the larynx, and downwards
 on the side of  the-trachea  and of the oesophagus.  Frequently
 from the superior part of  the isthmus, and most commonly on
 its left side, a  small pyramidal process runs upwards in front of f
 the cricoid and of the thyroid cartilage, and is attached, by liga-
 mentous fibres to the os hyoides; this process, however, varies
 much in size and length; I have never seen it double.   Accord-
 ing to Morgagni and Meckel, its existence is much more  com-
 mon than its absence, which corresponds with my own obser-
 vations.  The thyroid gland, when extended, measures  about
 three inches from side to side. 
140
ORGANS OF RESPIRATION.
   It is covered  in front  by the sterno-hyoid  and thyroid mus-
 cles, and laterally by the omo-hyoid  and the sterno-mastoid.
 Embracing the trachea and the sides of the Jarynx, its lobes re-
 pose upon the primitive carotids, and  the internal jugular
 veins.
   The  thyroid  gland has a capsule which is  not very easily
 raised up, but serves to  give it a polish;  it is also invested by
 the condensed cellular membrane of the part  called fascia pro-
 funda colli.  Its surface is smooth and  uniform.   It is of a dark
 brown  colour.  When cut  into or  torn, it is  seen to consist of
 several lobules adhering  to each other; but this arrangement is
 not very distinct, except in  an enlarged or diseased state;  and
 may be traced most easily by following the course of the large
 blood vessels, which pass in the interstices between the lobules.
 The latter contain many small  vesicles, or  cells filled with a
 transparent or yellowish and somewhat unctuous fluid: the cells
 are  frequently in a collapsed state,  which prevents them from
 being manifest to the naked eye.
   There are four considerable arteries  which supply this body,
 two on  each side, one coming from the external carotid and
 the other from the subclavian.  The veins follow the course of
 the arteries for the most  part.  Bichat  has made a very inte-
 resting remark on the subject of its blood vessels; that, notwith-
 standing their size and number, and minute ramifications in it,
 much less blood remains  in its capillary system than in that of
 the liver or kidney, as is proved by the quantity of  water it
 tinges in maceration; he, therefore, infers that  the capillary
 system is less  abundant.
   Anatomists  have sought in vain for  one or more excretorv
 ducts to this body/and some have imagined that they had found
 them terminating in the  trachea, or in the larynx.  Santorini
 considered the pyramidal  process from  4he isthmus as the  de-
 sired duct.  The emphysema with which  the gland has some-
times been affected, was  supposed to be a proof of its commu-
nicating with  the trachea by excretory tubes: but it is more
probable that  the air was forced into  the  cellular substance,
nuiting its lobules, and not into the structure itself of the gland.
   The settled opinion now seems  to be, that  whatever fluid it
secretes is conveyed away by the lymphatic  vessels.  Meckel
has suggested, that as this gland is more  voluminous propor* 
THE THYMUS GLAND.
141
tionately in early infancy, particularly its pyramidal process,
possibly the duct may be obliterated when the gland begins to
be restrained in its growth; but, if this were the case, the duct
ought  to  have been  found during the period indicated.   The
probability is, that it  is a diverticulum of blood from the saliva-
ry glands  during  the intermittence  of their action;  and from
the marked sympathy between  it and the  brain  in  goitre,  it
may exercise a  corresponding  function  on this organ during
its intervals of repose.
   Duverney* has described  a  small azygous  muscle on the
middle line of the body, coming from the under margin of the
base of the os hyoides, and running over the middle of the thy-
roid cartilage, to  be  inserted into the upper margin of the isth-
mus of the thyroid gland.  Soemmering calls it Levator  Glan-
dulas Thyroideas, and speaks of it as being  found more frequently
on the left side, and about half of the  breadth  of the thyreo-
hyoideus.   After many special examinations for it I have  found
it in but few instances; I, therefore,  consider  it rare; though
without  a close attention to structure, the  pyramidal process
of the isthmus of the gland may, from the similitude of colour
and position, be very readily mistaken for it, which I have rea-
son to believe has been frequently the case.f  .Some  few fibres
are often found going to the isthmus  of the gland from the cri-
co-thyroid, and the thyreo-hyoid muscles, or from the thyroid
cartilage.

               SECT. III.--OF THE THYMUS  GLAND.

   This body (Glandula Thymus) is placed between the trachea
and the upper extremity of the sternum.   It is irregularly tri-
angular, its broadest part being above, and the narrower below.
In the adult,  it is in  a  collapsed and  shrivelled  state, and
scarcely  presents a  vestige of  what it once was; it is, there-
fore, only in the infant that it can be satisfactorily studied.

   * Essai D'Anatomie en tableux imprimes, pi. IV. Paris, 1745.
   ■f- The unassisted eye, in a strong light, is generally sufficient to determine the
structure; but in case of doubt, by boiling the gland, if there be muscular fibres
along this process, their longitudinal and parallel direction will become  evident;
they also may then be torn asunder, so as to be made still more distinct; where-
 as, the vesicular structure of the gland is not susceptible of division into fibres. 
142
ORGANS OF RESPIRATION.
  At birth, it is much larger, not relatively, but actually, than
it is in the adult, and extends from the body of the heart up to
the thyroid gland.  It  is of a  very soft consistence and of a
pink colour.  It is  surrounded by a  capsule  of cellular sub-
stance, which, when removed, permits the gland to be resolved
into two  lobes, one  on  either side, which adhere to each other.
These  lobes  may be  separated with  facility into lobules, and
contain a whitish fluid.
  A good Essay on the structure of this gland, has latterly been
published by the distinguished British  surgeon and anatomist,
Sir Astley Cooper,* illustrated by excellent plates.  From this
it appears that the lobules of the gland are formed  of vesicles
of various  sizes, all discharging  into a duct which runs from
one end of the gland to the other, the consistence  of  which
duct is extremely feeble.  This  duct and  the vesicles may be
filled with an injection, by means of a pipe introduced into the
substance of the gland.  A large lymphatic trunk passes from
the gland, on each side, into the transverse vein.
   Sir Astley thinks, or, rather, asks, whether  this gland does
not prepare  a fluid for foetal  nourishment, in  the absence  of
proper chylification, during foetal life? inasmuch as all the ele-
ments of the blood are upon  chemical analysis, found  in the
fluid contained in its cavities.
   It is visible in the third month of gestation, and continues  to
grow till the end of the second year of extra-uterine life.   It
then collapses, and its structure is effaced about the twelfth
year;  its remains  are scarcely distinguishable subsequently
from the surrounding  cellular substance.   No excretory duct
has been found for  it, unless we may consider as such the lym-
phatic trunk  alluded  to  by  Sir Astley  Cooper.  Though  it
clearly belongs to fcetal and infantile existence, its use is pro-
blematical.   The probability is, that it  is a diverticulum  of
blood  from  the lungs during their state of quiescence in fcetal
life, and  until their  structure becomes confirmed  and  propor-
tionately evolved.
* London, 1832. 
THE LUNGS.
143
                   CHAPTER  III.

                      OF THE LUNGS.

  The Lungs (Pulmones) are the essential  seat of the process
of respiration, and occupy the  greater part  of the cavity of the
thorax, as formed by the ribs  and the intercostal  muscles  on
the  sides, by the sternum and its cartilages in front, by the dor-
sal  vertebras behind, and by the diaphragm below.   They are
two bodies, placed one on either side of the thorax, and separated
from each  other  by the heart and its great vessels.  As the
heart is the only organ of  much volume which is also included
in the cavity of the thorax, the size of the  lungs is in a direct
relation with the  capacity of the latter; and may, therefore,
be  known  by  external indications  in the living body.  It is
probable that there is no  void, or only a very small one,  be-
tween the sides of the lungs and the  sides of the thorax.
  Each  lung  forms an irregular cone, the apex of which is
above, and the  base below; the  latter, from resting upon  the
diaphragm, is, consequently, oblique from before backwards and
downwards, and  is also concave.  The surface which reposes
against the periphery of the  side of the thorax, is, uniformly,
rounded, but that which looks towards its  fellow, is concave,
from being pressed in by  the  heart.   The vertical diameter of
the lung behind, when it is fully distended, goes from the head
of the first to that of the last  rib, and isr from the oblique di-
rection of the diaphragm, consequently, much more considera-
ble than  the vertical diameter  in front, which extends only from
the first rib to the inferior end  of the  second bone of the ster-
num, or, in other words, to a level with the tendinous centre of
 the diaphragm.
   The lungs of the adult are of a light pink colour, with specks
 or patches of black: in early life  there is much less of the lat-
 ter, and in advanced life it becomes more abundant.
   The  left  lung is divided into two lobes by a  deep fissure,
 which begins behind, on  a level with the  fourth dorsal verte-
 bra, and runs  obliquely downwards and forwards to the ante- 
144                ORGANS OF RESPIRATION.
 rior margin of its base.   A  deep fissure in a  nearly similar
 situation is observed on the right lung; but from it another fis-
 sure branches out forwards, by which the right lung is divided
 into three lobes.   The internal face of the  left lung is also ra-
 ther more concave than that  of the right, from the side of the
 heart  projecting into it.  The right lung is more voluminous
 than  the  left, which corresponds with the greater size of the
 bronchus on this  side, but its vertical diameter is not  so great,
 from the pressure of the liver from below; though this  diameter
 is increased by the descent of  the liver when we are upright.
   Near the middle of the internal face of each lung are  to be
 seen the points of connexion  with the bronchia, and  with the
 pulmonary vessels.  Before these  the anterior margin is thin,
 and more or less winding where the lung is introduced between
 the heart and the front parietes of the thorax.  When the lungs
 are fully inflated,  only a very small  portion of the front of the
 pericardium can be  seen  between  them.   The posterior  mar-
 gin is  thick, and rounded where it rests  against the vertebral
 column.
   The whole rounded circumference of the  lung as well  as its
 base, though they are in contact with the parietes of the thorax,
 do not adhere  at any point to them.  The connexion of the
 lung, constituting  its  root, as  it is called, and by which  it is
 maintained in its situation, is entirely on the side of its  concave
 face,  where the pulmonary vessels  and bronchia enter, and
 though other attachments are frequently found springing  from
 different  points  of the thorax, they are purely  the results of
 disease.

                Of the Texture of the Lungs.

   Each lobe of the lungs  is divided into a great many distinct
 lobules, which  adhere together by intermediate cellular tissue.
 The marks of these  divisions  are apparent  on the surface by
 lines running  in different  directions,  but they are made still
 more distinct by tearing them  asunder.  The Lobules are sub-
 divided into very fine air vesicles or  cells, which may be con-
sidered as the  terminations of the ultimate branches of the
bronchia.   The opinion is  generally held, that the cells do not 
THE lungs.
145
communicate laterally with one another, as the cells of the
bones, but only with the ramifications of the bronchia, to which
they respectively belong.  Recent preparations, however, have
induced me to abandon this idea, and to conclude that the cells
of the  lobules individually communicate, but not those of dif-
ferent lobules.  I have succeeded in proving this by distending
the air cells with tallow, and, after the lung was dried, by re-
moving the  tallow with  spirits of turpentine.   This process
shows  the cells of their natural size, and communicating freely.
A very small portion  of a  lung of either the  human subject
or the calf kept inflated and dried shows the same unequivo-
 cally.
   In tracing the terminations of the bronchia, in the substance
 of the lungs,  the parietes of these canals are observed to become
 very thin, and especially after  the cartilaginous structure has
 ceased.   The ramifications seem then to be composed almost
entirely of muscular fibres, and a lining of mucous  membrane ;
 the latter is  smooth, polished, and so thin that it is  a mere film,
 about  the thickness and transparency of the  peritoneum, where
 it covers a  small intestine.  Longitudinal  folds may still  be
 traced in the length of the mucous  membrane, and, with the aid
 of a lens, mucous  follicles are very perceptible, in  innumerable
 quantities all over  it.  It may also be remarked, that  the bronchia
 do not end by a regular succession of proportionately finer and
 finer branches;  but that a bronchial  trunk, of some lines in
diameter, sends off in different directions to the contiguous  lo-
 bules, branches about the size of a bristle, which  are followed
 with much difficulty, owing to their collapsing: the probability
 is, however, that each one of these branches belongs to a lobule
 and discharges into its cells, in a. manner resembling a blow-
 pipe fixed to the side of a small piece of sponge.   In my pre-
 parations, these terminating tubes of  the bronchia, the size of
 bristles, are  seen  very distinctly;  but  there is no appearance
 of the penicillous arrangement,  which  would  be apparent if
 each air cell had its own specific branch of the bronchus run-
 ning to  it.
   Besides the ramifications of the bronchia, the substance of the
 lungs is composed of numerous blood vessels and lymphatics, an J
 is well supplied with  nerves.
   The blood vessels are of two kinds, the  pulmonary and  the
    Vol.  II.—14 
146
ORGANS OF RESPIRATION.
bronchial.  The pulmonary artery, coming from the right ven-
tricle of the heart, divides under the arch of the aorta into two
large branches: one for the right lung, and the other for the left.
The right branch is larger than the left.   Each of these branches
having reached the upper part of the root of its respective lung,
begins there to distribute itself in large trunks, which divide and
subdivide throughout the substance of the lung. The terminating
branches finally become capillary, and ramify in the parietes of
the air cells, where the blood  which  they carry, from being
dark-coloured and venous, is so altered as to  have the arterial
qualities restored to it, and to become of a bright red.   From
the ultimate branches of the  pulmonary  artery, arise  the first
branches of the pulmonary veins.   These are successively ac-
cumulated  into two large trunks on each  side, which, issuing at
the lower part of the root of  the lung, go to open into the left
auricle of the heart.  It has been remarked by Mr. Boyer, that
the two pulmonary  veins are  less capacious than the pulmona-
ry artery of the same side in which they  manifest a peculiarity
of  blood vessels, differing from what  exists in other  parts of
the body.  The pulmonary artery  and veins  are distributed in
company with the  bronchia.   From  the observations of Pro-
fessor  Mayer, it appears that  valves exist in the pulmonary
veins,  contrary to  the  general opinion of anatomists.   They
are found where smaller trunks join the larger ones, at an acute
angle, but there are none when they join at a right angle.*
   The second order of blood vessels,  being the bronchial, also
consists in arteries  and in veins, and are  for the nourishment of
the lungs.  They, too, attend the branches of the bronchia. The
arteries pervade the substance  of  the lung by innumerable fine
branches,  and  anastomose with the pulmonary arteries.  The
bronchial veins also anastomose with the pulmonary veins, but,
 finally, come out in small trunks from the root of the lung: the
 right one  empties  into the vena  azygos, and the left into the
 trunk of the superior intercostal veins of the  left side about the
 third dorsal vertebra.
   The Lymphatics of the lungs are numerous ; after traversing
 the black  bronchial glands, those of the left side empty into the
Am. Med. Jour. vol. iii. page 186. 
THE LUNGS.                      147
thoracic duct, and those of the  right into the large lymphatic
trunk coming from the right upper extremity.
  The nerves come principally from the par vagum.  Some of
them  are  distributed with the  bronchus, and  may be traced
easily  far along its branches, forming  beautiful  anastomoses
around them: their texture there resembles much that of the
sympathetic: they are thought to be, finally,  spent upon the mu-
cous  membrane: others seem to be more  specifically appro-
priated to the vessels.
   It wiH now be understood that the root of each lung is formed
by the pulmonary artery, the two pulmonary veins, and the bron-
chus, covered by the  pleura, where the latter extends from the
lung to the pericardium.  The relative situation  is such, that
the  pulmonary artery is above,  the bronchus in the centre and
behind, and the pulmonary veins below.
   The texture  of the lung is  so light and spongy after an ani-
mal has  once breathed, that its weight is very inconsiderable
when compared with  its volume.  Its cells are left much dis-
tended, even when the animal is  dead; and,  notwithstanding
from its  unusual elasticity, it  expels a great quantity of air
when the thorax is opened, and is thereby reduced to a third of
its size during life; yet it retains enough air to make it float in
water, or even  in gpirits of wine.   The quantity of air which
the lungs contain differs very considerably in different individu-
als, depending entirely on  the capaciousness of the thorax.  Its
medium amount is computed at one hundred and  forty-five cu-
bic  inches,  thirty cubic inches of  which are changed at every
act of respiration.


                       Of the  Pleura.

   Each lung has a perfect covering, called Pleura, to which  it
is indebted for its shining surface.  This membrane is  also re-
flected from the internal surface of the lung  to the adjacent side
of the pericardium, and is then spread  over the interior peri-
phery of  that half of the  thorax to which  it belongs, by lining
the ribs and intercostal muscles, and covering  the convex face
of the diaphragm.  There are, therefore, two  pleuras,  each  of 
148                ORGANS OF RESPIRATION.

which is confined to its appropriate half of the thorax, so as to
line its cavity and to cover its lung.
  The pleura, as other serous  membranes, is a thin sac.  Its
circumference is entire, like that of an inflated bladder;  there
is, therefore, no point or line at  which one may exclusively be-
gin an account of its course and attachments.   To commence,
however, at the sternum;  the pleura  goes thence outwardly to
line  the  lateral parietes of the  thorax, as formed by the carti-
lages of the ribs, the ribs themselves, and the intercostal mus-
cles.  In this way it may  be traced around to the dorsal  verte-
bras, and over the convex  surface of the diaphragm.  In pro-
ceeding along the first rib, which is very oblique, it forms a sort
of bulging bag, which projects  towards the trachea, lines the
lower part of  the scalenus anticus muscle, and receives the up-
per extremity of the lung.  The pleura, having reached the dor-
sal vertebras from the ribs, passes from  their sides forwards to
the posterior part of the  pericardium, a very small portion of
which it covers.  It then goes upon the posterior face of the
pulmonary vessels and of the bronchus to the lung, and applies
itself closely  to the latter.  It then covers the  part of the lung
posterior to its root, and continues to advance along the round-
ed surface of the lung to its anterior margin: it then passes over
the internal surface  of the lung, which  is anterior to its root;
It afterwards covers the front of the  pulmonary vessels  and of
the bronchus, and gets in a very short space to the pericar-
dium.   It then passes forwards on  the side of the latter, and
having got near its middle line, goes from it to the sternum, and
reaches the line from which the description of its course com-
menced.
  There is no important difference  between  the two pleuras,
either in their mode of reflection or in the organs to which they
are attached, so that the description of one will apply to the
other.   The portion of each pleura covering the lung is  called
Pleura Pulmonalis, and  that portion which  lines the thorax is
the Pleura Costalis;  that covering the Diaphragm is the Pleura
Diaphragmalis.  A  duplicature  of the pleura commences.at the
inferior margin of the pulmonary veins, and, descending as far
as the diaphragm, attaches the inferior portion of the posterior
margin  of each lung to  the side of the pericardium in front- 
THE LUNGS.
149
  of the vertebras.  This duplicature is the Ligamentum Pulmo-
  nis. It is longer on the left lung than on the right, by reason of
  the greater vertical diameter of the former.
    From what has been said it will now be readily understood,
  that the whole cavity of the thorax is divided vertically into two
  halves, by that portion  of the two pleuras which advances from
  the spine  towards  the sternum.  This septum is called the  Me-
  diastinum, and the  heart, enveloped by the pericardium, is placed
  in its centre, and separates the two pleuras widely apart.  It has
  been found useful by  anatomists, for descriptive  purposes, to
  subdivide the mediastinum into three portions or regions.  One,
  passing from the front of  the pericardium to the posterior face
  of the middle line  of the sternum, is the Anterior Mediastinum;
  another, passing from the  posterior face  of the pericardium to
  the dorsal vertebras, is the Posterior Mediastinum;  and a third,
  which is within  the circuit of the first ribs, is the Superior Me-
  diastinum.  This division, though evidently arbitrary, is  indis-
  pensable to a correct account of the relative situation of very
  important organs placed between the two pleuras.

    1. The  Anterior Mediastinum is less important than the other
 two; the portions of the two pleuras of which it consists are al-
 most in contact, and contain between them some loose cellular
 substance by which they adhere together, and by cutting through
 which, after  a  longitudinal section  of the sternum, they are
 easily separated from one another.   The upper part of this sep-
 tum contains the remains  of the thymus gland; its lower part
 leaves the middle line of the  sternum, and inclines to the left
 side; and  when the sternum is  narrow below, it is  attached to
 the anterior ends of the cartilages of the  lower  true ribs.

   2. The Posterior Mediastinum, where  it leaves the vertebra
 to reach the  pericardium, passes off from a  line nearer the
 heads of the ribs on the left side, than on the right,.  The de-
 scending portion  of the thoracic aorta is contained within this
 septum, on the left side of  the dorsal vertebras.  The oesopha-
gus is  in its middle  in front of the  vertebras above, but, in de-
scending it crosses in front of the aorta, and  inclines to the
left side of the dorsal vertebras to reach the foramen cesopha.
geum of the diaphragm.  The  vena azygos occupies the  rigbl
                            14* 
150
ORGANS OF RESPIRATION.
side of this  mediastinum, and, after ascending, forms an arch
over the root of the  right lung, and terminates by joining the
descending cava.  The thoracic duct, after entering the thorax
between the crura of the diaphragm,  ascends  in  front of the
dorsal vertebras between the aorta and the vena azygos, and
behind the oesophagus, till it reaches the third dorsal vertebra;
it then inclines to the left side, and mounting into  the root of
the neck near the vertebrae, it, finally, makes an  arch, which,
by advancing forwards, terminates in  the  angle formed by the
junction of the left internal jugular and left subclavian vein. The
par vagum nerve, of both side?, is also  in the posterior roedL-*
astinunu

   3. The Superior Mediastinum is bounded in front by the up-
per part of the sternum, behind by the upper dorsal vertebras^
and laterally by the first ribs.  The cavity is conoidal, with the
base upwards, but is too peculiar to admit of a rigid comparison
with any thing else.  The pleuras are reflected downwards from
the internal  edge of the first ribs, not abruptly, but in a rounded
bulging manner, receiving there, as mentioned, the tip or apex
of the lungs, and lining the inferior surface of the scalenus an-
ticus muscle.  In order to understand well the position of the-
pleuras, it must be borne in mind that  the  upper  rib  is placed
very obliquely downwards and forwards, at an angle of about
forty-five degrees with the spine;  consequently, the pleura, on.
being reflected from its whole internal edge, is much higher at
the head of  the rib than it is at the anterior  extremity of the
same.  This cavity is  continuous,, of  eourse, with that of the-
anterior mediastinum in front, and also with that  of the  poste-
rior mediastinum behind.
  The remains of the thymus gland are where this cavity joins
the anterior  mediastinum: a parfof the gland is>indeed, in each
of these cavities  just below the transverse vein.   In contact
with the right pleura is the descending Vena Cava.  The com-
mon trunk of the  Left Subclavian, and Internal Jugular tailed
the Transverse Vein, or Vena Innominata, after crossing in an
oblique descent behind  the upper portion of the sternum, joins
the descending cava an inch  above the place  where the latter
penetrates into ihe pericardium.  Behind  the  transverse vein
are the top of the arch of the aorta, the arteria innominata, the 
THE LUNGS.                     151
left carotid, and the left subclavian.  The trachea, with  the
oesophagus behind  it, descends along the middle line in front of
the spinal column. The arteria innominata crosses the front
of the trachea from left to  right in ascending; it is in  contact
with the transverse vein, and  more  superficial than either,of
the other arteries.   The phrenic nerve, passing at the  internal
edge of the scalenus  anticus, between the  subclavian artery
and vein, descends vertically in contact with the pleura. The
par vagum passes  along the side of the trachea, and afterwards
behind the corresponding bronchus, having got into the superior
mediastinum between the subclavian vein and artery:  its infe-
rior laryngeal branch encircles the subclavian  artery on  the
right side,  and the arch of the aorta on the left.

   The internal surface of the pleura is smooth and polished, and
is moistened and kept lubricated by an unctuous serum, the na-
tural  quantity of which Is merely sufficient to allow the parts to
slide freely upon each other.   In dropsy of the chest, it is aug-
mented frequently  to such an  amount as to cause the collapse
of the lung by pressing upon it..
   In the cellular tissue, between the pleura and pericardium, as
well as on the diaphragm, adipose matter, in considerable abun-
dance, is found in corpulent persons advanced in age.
   The blood vessels of the pleura costalis are derived from those
which supply the parietes of the thorax, as the intercoslals and
phrenics.  They ramify in the subjacent cellular substance, and
end by exhalent orifices on  the internal face of the pleura, from
which, a minute injection is poured out very copiously. 
 
BOOK  VIII.
           OF  THE CIRCULATORY SYSTEM.


                       PART  I*

      Of the General Anatomy of the Circulatory System.
                                               r

                    CHAPTER  I.

                GENERAL CONSIDERATIONS.

  The Circulatory or the Vascular System, consists in a conge-
ries of tubes, or cylindrical canals, which convey the blood to
and from every part of an animal body,and therefore, enter into
the texture or composition of almost every portion of it.  In all
animals there seems to be a necessity for the alternate reception
and discharge of alimentary materials; in the higher orders, this
is effected through the agency  of the vascular system; but in the
most simple animals this system does not exist, and their whole
fabric being soft and permeable, nutritious-matter is introduced
by a direct absorption, or a species of capillary attraction, after
the manner of a sponge, or any other porous body, and is dis-
charged by a process equally simple.*  It is probable that there
are some parts of the human  body whose mode of nutrition is
analogous to the latter;  as, for example, the articular cartilages,
the hair, nails, and so on; for  many observations tend to prove
that all these organs have an interstitial circulation.
Hunter on the blood. Beclard, Anat. Gen. 
154
CIRCULATORY SYSTEM.
  In many animals, the blood is propelled from a central point,
called the heart, to all parts of the body, and then returns again
to the heart.   The first movement is  executed through canals
called  arteries, and the second  through veins.  It is the  most
simple scheme by which a circulation can be carried on through
a sanguiferous system, and requires a heart with only two cavi-
ties; one for propelling blood into the arteries, or departing tubes,
and another as a reservoir for receiving the blood of the return-
ing tubes, or the veins.  The two cavities must be near each
other, and have a valvular  opening between  them, which will
permit the blood to pass from the venous into the arterial reser-
voir; but not from the arterial into the venous.   A  circulation of
this simple cast is found in fish, and in animals generally whose
respiration is effected on the surface of the body; but  in man,
and in other warm-blooded animals, where respiration is carried
on interiorly by means  of the lungs, their ctrculat6ry apparatus
is double; one part being for the lungs, and the other part for
the body generally.
  In man, the heart consists of four cavities: two auricles, or re-
servoirs of venous blood, and two ventricles, into which the ve-
nous blood is transmitted, and which, in their functions, may be
compared to the forcing-pump of a fire-engine.  The circulation
is effected in the following manner: The blood contained"in the
right auricle of the heart flows into the right ventricle, and from
the latter it is forced  through the pulmonary artery into the
lungs.   It returns  from the  lungs through the four pulmonary
veins, and is received into the left auricle of the heart; from the
latter it flows into the left ventricle, and is propelled from it into
the aorta.  The aorta then distributes it through the whole body
by an infinitude of small branches; from the latter it is collected,
by corresponding veins, into two trunks, the Ascending and the
Descending Cava.  The ascending vena cava brings the  blood
from the lower extremities and from the abdomen; the descend-
ing vena cava brings the blood from the head  and neck, the up-
per extremities, and the parietes of the thorax.  These two trunks
finally discharge the blood into the cavity from which it started,
to wit, the right auricle.  The same round  is then renewed, and
continues to be repeated during the whole course of life.   It is
customary for anatomists to call the route  of blood from the
right ventricle, through the lungs, to the left auricle inclusively 
GENERAL CONSIDERATIONS.                155
the lesser or the pulmonary circulation; and that which begins
at the left ventricle, goes through the whole body, and ends in
the right auricle, the greater circulation.
  The blood contained in the veins of the greater circulation, in
the right auricle and ventricle, and in the pulmonary artery, is
of a dark brown or reddish colour; while that contained in the
pulmonary veins, in the left auricle  and ventricle, and in the
aorta and its ramifications, is, from  being vivified by  respira-
tion, of a carmine or vermilion complexion.  The celebrated
Bichat has, upon this difference of colour, founded his  division
of the whole circulating system into two parts;  one containing
black blood, "Systeme vasculaire a sang noire;" the other red
blood, " Systeme  vasculaire  a  sang  rouge."   This  division
having general physiology for its object, affords  a well  marked
distinction, suited to  such discussions.
   The lymphatics also are a part of the circulatory system, but
as they do not  commonly convey red blood,  the consideration
of them will be introduced subsequently.  " They take a very
active part in the animal economy, whether natural or diseased,
and seem, in many actions, to be the antagonists of the arteries,
while the veins are much more  passive, being principally em-
ployed in returning the blood to  the heart."*
   The largest vascular trunks are situated near the centre of the
body and limbs, on the side upon  which flexion is  accomplished,
while those near the  surface are generally  small.  Most com-
monly there are one artery, one or two  veins, and several lym-
phatics, all.together.
   The arterial  system in its external configuration may  be com-
pared to a tree, the trunk of which is attached to the heart, and
which by a continued  succession of divisions and subdivisions
reaches to every part of the body.  There are no means of esti-
mating rigidly the collective area of the branches in proportion
to that of the trunk, but a little  observation on the size of the
primitive branches will satisfy one of a great excess on  the part
of the latter; and as the rule is maintained  throughout, there
must finally be  an immense disproportion.   We have then rea-
son to believe,  that if all  the  branches were assembled into  a
single cavity, this cavity would  be somewhat like a cone, the
* Hunter, loc. cit. 
156
CIRCULATORY SYSTEM.
apex of  which would be next  to the heart.   The  same rule
holds in regard to the venous system, it being observed, how-
ever, that the latter has two trunks connected with the heart in-
stead of one. The general rule is, therefore, established through-
out the vascular system, that the collective area of the branches
is  always greater than that of the trunk from which they pro-
ceed.*   By the same rule the circulation in the branches must
  * I am indebted to a scientific friend, Mr. Erskine Hazard, for the following
computation, by actual measurement, of the arteries, from which it appears that
in many of them, at least, the area of the trunks is greater than  that of the
branches near them. *"

  The Left Carotid at the Aorta is........42
  Its diameter at the branching is......-    -    .43

                 Increase of diameter     -.....01

  I ts square at the Aorta is.......-  1764
  Each Carotid branch  measures .23, and the sum of their squares
    is    ------------  15GS

  The difference of the areas of the Carotid and its branches is 12 J  per cent, in
favour of the Carotid.

  Diameter of Aorta near the Iliacs.......64
            Its square.........4096

  Diameter of Left Iliac  -*-.»,.   .40
            Its square.......       1600
  Diameter of Right Iliac.......37
            Its square      ......       1369

                Sum of their squares   -    -    .    „    .     -  2969

  Aorta largest by nearly 38 per  cent., or -.....1127

  Square of Right Iliac, as above,   ----...  1369
    Ditto  External Iliac     .......    goo
    Ditto  Internal do.  -    -     -    -    .    .     .    .    739
                                                        ----1629

  Branches largest by nearly 19 per cent., or.....260 
GENERAL CONSIDERATIONS.                    157
be more languid than in  the parent trunks, as this circulation is
retarded  both by additional friction  and  by having  to fill up a
Square of Left Iliac, as above,
  Ditto  Internal Iliac
  Ditto  External do.  -
1600
961
900
1861
Branches largest by above 16 per cent., or  -
261
Great Sinus of Valsalva    ...     ...    -    .    .     -   13456
     Innominata.........2601
     Carotid     .........   1444
     Subclavian.........1024
     Aorta beyond........3600
                                                         ----  8669

Sinus greater than all, by--------    4787
     or 55 per cent.

Comparison of the areas of the Iliac Arteries, with that of the Aorta, half an
                inch above them, in decimals of an inch.

                               Left Iliac.        Aorta.         Right Iliac.
  Greatest diameters     -    -    .354           .556             .390
  Least      do.   -    -    -    .290           .410             .290
Sum of diameters
.644
.966
.080
Mean diameters
.322
.483
.340
Their squares
-  103684
233289
Sum of the squares of the Iliacs  -
          Square of the Aorta  -
115600
103684

219284
233289

 14005
     Aorta larger than the Iliads     -    .....
         or nearly 6*  per cent.
  As the areas of circles are to each other as the squares of their diameters, it
follows that the aorta will contain, in a given length, nearly GJL per cent., more
than the two iliacs; and, consequently, the  blood must flow that much faster
through the iliacs than through the aorta, as the same blood has to be disposed
of in both in the same time.  By this means  the power of the heart is  continued
much farther through the system, as each artery is large enough  to  supply its
branches with but little friction.  The  interior surfaces of the above iliacs  arc
together, 2.0806 inches, while that of the aorta is but 1.518 inches or only three
  Vol. II.—15 
158
CIRCULATORY SYSTEM.
larger canal.*   The course of rivers exemplifies this continual-
lv; while confined to narrow channels, they rush  tumultuously
through them, but when they begin to expand themselves into
capacious basins, or to be  divided  into a multitude of smaller
channels, the current becomes slower, and in some cases imper-
ceptible, though  the fact is clear, that an equal volume of wa-
ter is every where descending in the same period of time.
   The  moisture  conferred  upon all parts by the circulation of
the blood, bears  a sufficient analogy to the effects of irrigation
upon ground.  The water may be conducted  to the latter by a
canal, which is finally divided into an infinitude of  streamlets,
which ramify every where, and from the porosity of their beds
percolate laterally, so that the whole  field,  even to its most
minute  atom, is kept  moistened.   The  streamlets, afterwards,
successively assemble again into a single canal, which bears off
their superabundant water.   From the nature of the particles of
blood, many of them are confined to their'proper channels, and
can never pass off by percolation into the tissue, through which
the blood vessels ramify.   This may be proved by the fact that
the red  globules  of blood  have a diameter of from  the two-
thousandth to the five-thousandth part of an inch, a size incon-
siderable as it is,  yet too large to permit their flowing through
elementary fibres or atoms; whereas scrum, or the water of the
blood, may, from the extreme fineness of the particles, be ab-
sorbed  by any  tissue whatever;  a circumstance entirely un-
questionable, both from daily observation, as, for example, in
soaking a piece of dried meat or a bene; aid from the reflec-
tion, that the air itself will hold a certain quantity of water in
solution.
   A question then arises whether the moisture of parts not sup-
plied with red globules of blood, comes in the living  body ex-
clusively from infiltration or from a peculiar set of vessels called

fourths of the rubbing surface.  Independently of this circumstance, it is found
that there is a greater difference in the quantities of fluids passing through aper-
tures of different sizes than there is in the areas of the respective apertures.
This is accounted for by there being less friction between  the particles of fluids
than there is between these particles and a solid; and, in the larger apertures, a
smaller proportion of the particles comes in contact with the solid.
  * It is computed that the blood moves 5233 times slower  in the capillaries than
in the aorta. 
GENERAL CONSIDERATIONS.
159
exhalents, often talked of, but as yet never  seen?   That  the
iateral porosities  of  blood vessels are large  enough  to allow
watery fluids  to  exude, is readily proved  by injecting water
into the blood  vessels of a limb, or of any other part, when  the
latter invariably becomes cedematous.   It is  in  this way even
possible to inundate a living animal, as I have seen accomplished
by  M. Magendie, in Paris.   This moisture  requires a change,!
and by continued additions would become superabundant: as it
has been thrown out of the common current  of the circulation
and could not be  removed in any other way, the lymphatic sys-
tem has, therefore, been added  for the purpose.   In the lower
orders  of animals,  who are destitute  of the  blood  vessels, the
interstitial change of moisture goes on without lymphatics.
   No part of the human  body  is exempt  from moisture,  but
it is  furnished by smaller streams, and is  also  less abundant
in  some textures than in  others; for example,  though blood
vessels susceptible of conveying red blood do ramify through
tendons and ligaments, yet they are not numerous, apparently;
not more so, indeed, than what is sufficient to keep up by a de-
posite of serum, the flexibility of those parts.   The  vascularity
of  a  part during life may be ascertained by a simple process
after  death, the most vascular always  lose  proportionately of
their bulk by  drying; for example, a muscle  shrinks more than
a tendon, a gland more than a muscle.

   Besides the operation of the lymphatics, much of the super-
abundant moisture  is carried oft' by insensible perspiration and
evaporation  from the surface of the body:  the latter process,
however, is much restrained by the peculiar character of the
cuticle, without  which it would  become  excessive, probably
so  much so  as to   exceed  any supply of  fluid through  the
stomach.

   The red globules  of the blood, besides their less obvious uses,
 unquestionably serve to inspissate  the  serous or watery part,
 by an  intimate mixture with it, and  thereby put a certain re-
 straint upon its extravasation.   They also, from their size, serve
to  keep open  the channels through which the blood circulates.
 So much associated is the existence of red globules with regular
 blood vessels, that there are  but few examples of animals having 
160
CIRCULATORY SYSTEM.
the former, without also having the latter; whereas, in animals
whose circulating fluid has not red globules, but is a mere serum,
the entire destitution of regular blood vessels is very  common,
and their circulation, if  the name be  deserved, consists simply
in the transmission of moisture  from one pore to another, as oc-
curs in a rag or in a sponge, by mere capillary attraction.  Such
animals form a numerous class in the chain of organized beings,
and have a gelatinous consistence.

   A remarkable feature in the vascular system, both arteries
and veins, is the disposition of  trunks to run into one another;
or, in other words,  to  form  an anastomosis, whereby, if the
blood should be cut  off by one  route, it  may still be  supplied
through another.  These  communications are  frequent in the
head, in the neck, in the thorax, in  the abdomen,  and in the
extremities; they exist,  indeed, wherever the blood vessels do,
and become more numerous as  the blood vessels are smaller, or
more removed from  the centre of the circulation.  It is unne-
cessary here to specify instances, as the more  remarkable ones
will be  mentioned at a  proper  time.   But some estimate may
be made of their importance,  and of the facility of communica-
tion established by  them, when it is remembered that cases
have occurred of obstructed aorta, without the circulation ceasing
in the parts of the body  beyond it: the same  has occurred to th<?
vense cava?, and to the thoracic duct also,*

   The  extreme vascular  ramifications are  called  Capillaries,
(Vasa Capillaria,) and they form the connexion between the
arteries and veins; or, by being intermediate to the two, they are
the ultimate terminations of  the arteries, and the commencing
roots of the veins. From the extreme tenuity of these vessels, it is
impossible to indicate where the arteries terminate and the veins
begin; yet their continuity with the capillary system  has been
repeatedly demonstrated, by  throwing injections from the one
into the other system, and by microscopical observations made
on the transparent parts of living animals, as the mesentery and
web foot of frogs, and the tail of fishes.  These facts are suffi-
ciently substantiated  by the  observations of Malpighi, Lewen-
* B^clard, Anat. Gen. 
CAPILLARIES.
161
hoeck, Prochaska, and a crowd of others; yet there are anato-
mists who hold a contrary doctrine, and admit the parenchyma
of the ancients (an indefinable something, conceived, however, to
be spongy) as  a  point  of  termination  for the arteries, and  of
commencement for the veins.
  Though the  capillaries are all too fine  to  be seen distinctly
without the microscope, yet they are found to have several gra-
dations of size.   The  largest  of them are those which only
escape the naked eye, experience successive divisions, whereby,
their diameters are reduced from admitting a  file  of  several
globules of blood to the caliber  of one  globule  only.*  The
capillaries have also  frequent anastomoses with  one another.
Sometimes the artery is simply doubled on itself,  and immedi-
ately becomes a vein:  on other occasions, several capillary ar-
teries  run into the same vein.   When these communications
are unduly enlarged, they constitute what has been called  by
Mr. John Bell  the aneurism from anastomosis a frequent mark
in young children, and which, when  it  has  developed itself
fully, has a spongy structure resembling the erectile tissues,  as
the corpus cavernosum penis, &c.  As there  is a  double circu-
lation, so there is a double capillary system, one  for the lungs
and the other for the body generally: to these may be added a
third, which exists  in  the  liver, between the hepatic extremi*
ties of the vena portarum and the hepatic veins.
  The texture of the  capillary vessels  is  too fine to admit  of
much scrutiny, but they appear as simple  cylindrical excava-
tions  in the substance  of the part to which they belong.  It is
not improbable,  that they may be uninterrupted  continuations
of the  internal coat of the arteries into that of the  veins.   They
have striking powers of extension and  of contraction, and are
easily irritated.  An emotion  of the mind, as  a  sentiment of
shame or a feeling of  resentment, quickly causes those  of the
face to become  turgid with blood.  Local stimuli cause con-
gestions in  them.  Cold, the application of a weak acid,  or
fear, causes them to contract;  though, under the influence  of
the heart, they are less so than larger  vessels.  Their innume-
rable channels cause  a comparatively languid circulation  of
the blood in them, for  reasons mentioned; and by furnishing i^

                       * Beclard, loc. cit.
                            15* 
162                CIRCULATORY SYSTEM,
with more places of contact with their  parietes, put it more
under nervous influence than it is elsewhere.
  These vessels are not equally abundant in all the textures of
the body.  Their quantity may be ascertained by the redness
which a part acquires by inflammation, as well as by fine injec-
tions: the latter proof is preferable, as, in the former, it  is diffi-
cult to distinguish  them from the extravasations  which also
occur at the same time.  The celebrated injections of Ruysch,
from their unusual minuteness, induced him to think that every
solid portion of the body was vascular, yet  he admitted that
some portions were more vascular  than others, thereby con-
ceding to his  antagonists, that some points  at least were not
formed by  blood vessels.  In the microscopical  examinations
on living animals, for example, the frog, it is seen that in their
feet the smallest capillaries  are separated by distinct intervals,
while in the mucous membrane of the  lungs the finest needle
cannot have its point inserted without opening several of them.*
The younger an animal is, the more vascular are its parts: but,
on the contrary, as it advances in age, the proportion of parts
not susceptible of injection  increases, while  the capillaries  di-
minish in number.  In cold-blooded  animals, it is very  evident
that some of these capillaries,or arterio-venous communications,
are large enough to admit a file of several red globules abreast,
while others allow  a single  file only.  As a" general rule, their
diameter may be stated at  from one to  five  globules of red
blood,t

   The nutrition of the body depends upon  an alternation of
exhalation and of absorption; but it  is still undetermined, whe-
ther there  be any vessels whatever whose especial office is that
of exhalation, and  which produce the  several secretions and
exhalations.   If there be such, they are generally designated
by the term  exhalents, and   their diameters are too small to
transmit the red globules of blood; their function is, consequent-
ly, to give-passage to the serous particles only.   This subject
has been much  agitated by anatomists, and  marshals the best
authorities on both sides.  Among the distinguished advocates
in  the affirmative, are Bocrhaave, Haller, and Bichat;  and  op-
* Beclard, Anat. Gen.
t Beclard, loc. cit. 
EXHALENTS.
163
posed to them, are Prochaska, Mascagni, and Richerand.  The
leading facts of the former are; The microscopical observations
of Lewenhoeck, who speaks of vessels admitting  only serous
globules;  the  phenomena of inflammation, which render red,
parts naturally white and transparent;  the difficulty of con-
ceiving how the nourishment  of  certain parts can  be  main-
tained, whose  capillary system of red blood  is so limited, in
proportion to points not susceptible of it.  The opinion of Mas-
cagni and others to  the contrary, is: That those exhalents, if
they existed,  should  be  seen readily, inasmuch  as  they are
within the range of a microscope, whose powers enable one to
 examine  a body much smaller than a  red globule  of blood;
 that injections should penetrate them, instead  of being limited
 to vessels whose existence is sufficiently confirmed by exami-
 nation in  the living state; that if  during  inflammation they do
 seem to be  injected with red blood, the appearance is delusive,
 and depends upon the existing capillaries  being dilated so as to
 receive more  red blood than usual, upon the formation of new-
 vessels, and upon sanguineous infiltration; and  as  to  mem-
 branes naturally white, as the conjunctiva,  the colour depends
• upon the  capillaries, while in  a  healthy state, being so  small
 that they do not admit the red globules in a file sufficiently
 numerous to be perceived by the  eye; the  globules being, pro-
 bably, then conducted in  a series of one only, or in a  single
 file, like a string of beads.  It is, therefore, much more rea-
 sonable not to admit the existence of vessels  which  it  is very
 doubtful whether any one has seen.
   When  a  watery injection is pushed into a blood vessel, it in
 a little time shows itself as a fine dew upon the surface of the
 serous and  mucous membranes; in the cellular membrane, and
 elsewhere.  According to many anatomists, it has gone through
 the  system  of exhalents, and, indeed, presents itself  to  sight in
 very much  the same way that exhalation  occurs  in the  living
 state.  From the view which has just been taken, it becomes
 more probable, that this perspiration is executed  throuo-h  the
 interstices or  pores of the vessels.  In the dead state it is merelv
 a mechanical result, a simple straining of the fluid; whereas, in
 the living body it is a vital function, continually modified by
 the peculiar vital powers of the organ or membrane where it
 occurs;  and,  therefore,  presents itself under the form of the 
164
CIRCULATORY SYSTEM.
different secretions.  The question of the  exhalents  being  a
distinct set of vessels, does not, however, appear to be one of
much consequence; because, if they do exist, they must be very
short and very small; and the assumption of their existence does
not throw any light upon  the function  of secretion.   For the
latter is still an incomprehensible vital  process, and as far as
we have any idea about it, it is quite as easy to conceive of its
being performed in the parietes of the capillaries, as in the
mouths of a distinct set of vessels, whose length is too short to
admit of an estimate.
   Besides the supposed existence of a  general system of exha-
lent vessels, some anatomists have thought that there was a spe-
cies of them acting particularly as nutritive vessels.  According
to Boerhaave,everypart must,therefore,be vascular. Mascag-
ni thought that the extreme arterial  ramifications are not only
furnished with exhaling, but also with  nutritive porosities; and
that there are every where orifices of absorbing vessels, to con-
tain the  nutritive  molecules.   The  theories of Bichat and of
Prochaska, do not differ materially from the latter.  Whatever
may be the mode of existence, and the route of nutriment to the
several parts of the body, the operations involved are  entirely
too subtle even  for microscopic observation.  We, therefore,
can only understand,  in a  general way, that the blood vessels
deposite, and the lymphatics absorb,  by invisible avenues  in the
cellular substance, the molecules of composition  and of decom-
position in our organs.*  It is to this power that  the name of
vital force has been given, and especially that of the  force of
formation, (nisus formativus.)
   The arteries, though commonly said to be cylindrical canals,
are not exactly so, but, as they recede from the heart, increase
somewhat  in  diameter, even where they do not send off any
branches.  In this way the arteries of  the umbilical chord are
evidently larger as they get nearer the placenta; and the sper-
matic arteries of a bull as they  get nearer to the testicle.  Ob-
servations made on the carotid arteries of the camel, and of the
swan, by Mr. Hunter,f tend to prove  the same disposition in
them. It is probable that the rule extends to all arteries through-
out the system, but it  cannot be ascertained with so much cer-

       * Beclard, loc. cit.       f  On the Blood and Inaamrnatiojtv 
TEXTURE OF THE ARTERIES.               165
tainty, because of the close succession of branches which they
send off.  The vertebral  arteries afford a striking example of
the same.
  Arteries have within themselves a power of increase con-
nected with  the exigencies of the part to which they go: thus,
the uterine arteries increase much in their capacity during preg-
nancy, while the hypogastric, from which  they  are  derived,
augment inconsiderably, and  the primitive iliacs not in an ap-
preciable manner.   In  animals of the deer kind, whose horns
are deciduous, the same augmentation of arterial trunks occurs
while the horn is growing.  Tumours are supplied in the same
way.  But in all these cases, after the exigency is passed, the
vessels diminish  to their primitive size.
   With the exception of the semi-lunar valves at the orifice  of
the pulmonary artery and  of  the aorta, there are  no others  in
the whole arterial  system. These valves permit the blood  to
pass in the direction of the circulation, but  not backwards,  as
they are closed immediately upon the cessation of the  contrac-
tion of the ventricles.  The tricuspid valve of the heart, and
the semi-lunars of the pulmonary artery, are naturally not so per-
fect in their  closure as  those on the other side of the heart, but
permit a small quantity of blood to retrograde.*   As  life ad-
vances, the valves  of the aorta are much disposed to  ossifica-
tions and derangements of different kinds, which  render them
much less perfect than  those of the pulmonary artery,
                    CHAPTER II.

            OF THE TEXTURE OF THE ARTERIES.

  The arteries are composed of three coats; an external, a mid-
dle, and an internal.

  The External Coat, also called Cellular, is, in fact, condensed
cellular substance formed into a cylinder.  Its fibres run in eve-
ry direction, so as to be perfectly interwoven with one another.
The exterior periphery of this coat is continued into the adja-
*' Hunter, loc. cit. 
166
CIRCULATORY SYSTEM.
cent cellular substance, but its internal face is united more close*
ly to the middle coat; not, however, so tightly as to prevent a
slight sliding of the one upon the other, and to forbid their easy
separation by a knife.   Scarpa is not disposed to admit this as
one of the coats of arteries, and says that it only serves as an
exterior envelope, and retains  them in their places.  This coat
manifests  its  fibrous character in not  being disposed to secrete
fat, and is more distinct in the large arterial trunks.  It has con-
siderable strength and elasticity, both circularly and longitudi*
nally, and is remarkable for its whiteness.  If an  artery be sur-
rounded by a tightly drawn ligature, the middle  and  the inter-
nal coats  will be completely cut  through by it, while the exter-
nal coat remains entire.   This coat, then, answers the purpose
of a strong investing fascia,* in which respect it  may be consi-
dered as a sheath to the proper arterial structure, though  the
term sheath is  commonly applied to the cellular  membrane on
its outer side.

  The Middle Coat of the arteries is called  the  Muscular, the
Proper, the Tendinous, and so on.   It is of a light  yellowish
tinge, and decreases continually in thickness, with but few ex-
ceptions, from  the heart to the ends of the arteries; it is, how-
ever proportionately thicker in the small arteries  than  in  the
large ones.   lis fibres arc circular, but do not individually per-
form the circuit of the vessel.   They are parallel  to each other,
and adhere  laterally by very slender ties.  In the larger arte-
ries, this coat may be divided into  several laminae, though the
division is entirely artificial.  There are no longitudinal fibres
whatever in it; the consequence  of which is, that an  artery di-
vested of its external coat, yields more readily in the direction
of its length than of its circumference.
   The middle coat has a  firmness, whereby, even  when an ar-
tery is emptied, the cylindrical shape is still retained.   Its cha-
racter seems to  be  the result  of  a  mixture of  elastic and of
muscular  properties derived from a state of tissue entirely pe-
culiar; but which some anatomists have been very desirous of
ranging under  the head of muscles, others under that of  liga-
ments, and a third,  under  both  united.   The celebrated John
Jones on Hemorrhage. 
                  TEXTURE OF THE ARTERIES.               lv'

Hunter,  whose  observations were  generally made  with the
most scrupulous attention to perfect exactitude, were often re-
peated, so as to  make one  confirm another; and who has re-
ceived that  sanction of greatness in which  one's posthumous
reputation  becomes  more  exalted  than the living;  bestowed
much attention  on this subject.   He was induced to believe
that  this middle coat was formed by a muscular lamina  inter-
nally, and an  elastic one externally; which distinction  might
be rendered evident by cutting  a contracted  artery through
transversely, when the muscular coat would be found projecting
beyond the  other.  He  acknowledges, however, that  he  never
could discover the direction of the muscular fibres; though he
supposed them  to be oblique, because their degree of contrac-
tion  was greater than a straight muscle could produce.
   The elastic contraction of an artery, is manifested both in the
direction of its length and of its circumference; for, when put
upon the stretch in either way,  it has the ability  of returning to
its original dimensions after the distending force ceases.  The
muscular contraction, however,only occurs in the circumference,
and  not at all in the length: by it the caliber of arteries  is re-
duced to a very small diameter, if an animal be slowly bled to
death.   If, in this contracted condition, an artery be slit open
longitudinally, the elastic coat  will, at the cut margin, project
beyond the other, which Mr. Hunter considers as another way
of ascertaining the existence of the two tunics.  But if this same
artery be then  stretched transversely,  the  muscular coat will
project beyond the other; for the reason, that if a muscle, after
death, be elongated  by force, it has no power of returning from
 that state, but will remain precisely as it is: whereas, elasticity
being a  property of  matter enjoyed quite as fully in the dead as
in the living state, the elastic coat of the artery returns to the
medium condition.
   Mr. Hunter,with a view of satisfying himself on these several
points, had a  horse bled to death, so as to obtain the  vessels, at
 their minimum  of contraction.   A circular section of the aorta
 measured, at first, five inches and a half, and, on  being stretched,
it lengthened to ten inches and a half; being let alone,  it con-
tracted  to six inches, at which it remained stationary; the dif-
ference  between six inches and ten  and a half was then the 
168
CIRCULATORY SYSTEM.
 amount of its elastic power, while only half an inch of contrac-
 tion was  due  to  the  muscular stratum, *or, in other words, an
 eleventh of the whole.
   A section of the iliac artery, measuring two inches in circum-
 ference, on being allowed to contract after stretching, measured
 two and  one-third  inches; it, therefore, gained one-sixth the
 amount of its muscular  contraction.   A section  of the axillary
 artery gained one-eighth—of the carotid, two-thirds—of the ra-
 dial artery, doubled its  primitive extent.  From all which the
 inference was drawn, that the power,of recovery in a vessel is
 greater, in proportion as it is nearer the heart, but lessens as the
 distance increases, which shows the decrease of elastic, and the
 increase of muscular power.
   The  elastic coat gives a  middle state  to an  artery, or has a
 continued  tendency  to it; if, therefore, the  artery be too much
 dilated, it  contracts it, and if  it be too  much contracted, it di-
 lates it, all of which is readily exemplified by a cylinder of gum
 elastic, which, whether compressed or dilated, has only one state
 of repose, to which  it immediately returns  on  being left to it-
 self. Mr Hunter supposed, that a certain degree of elasticity
 is continued to the very end of every artery, from this quality
 being better suited to sustain a permanent resistance than mus-
 cular power;  as  a  pipe of lead,  from  its  want of elasticity,
 finally becomes stretched and  useless  under the  pressure of a
 column of water, whereas,  one of iron, from being elastic, al-
 ways re-acts  efficiently.  It is this  elasticity in  the arteries,
 which causes  the  blood, at a little distance from the heart, to
 flow through them in a continued jetting stream when they are
 opened, although it is supplied to the aorta by interrupted  strokes.
 In this way, as the artery is more distant from  the heart, ihe
 stream  becomes proportionately regular.
   "  The muscular power of an artery renders a smaller force
 of the  heart sufficient for  the  purposes of circulation; for the
 heart need  only act with such force as to carry the blood through
 the larger arteries, and then the muscular power  of the  arteries
 takes it up, and, as it were, removes the load  of blood while the
 heart is dilating.   In confirmation of this remark, it is observa-
ble in animals whose arteries are  very muscular,  that the heart
is proportionably weaker, so that the muscular power of the ves-
 sels becomes a second part to the heart, acting where the power 
TEXTURE OF THE ARTERIES.
169
of the heart begins to fail, and  increasing in strength as that
decreases in power."*

  The Internal Coat of the arteries  is designated by the  terms
Nervous and Arachnoid.  It is continued from the ventricles or
the heart, in the left one of which it  is of unusual thickness.  It
is the duplication of this membrane with some fibres interposed,
that composes the semi-lunar valves  of the aorta and of the pul-
monary artery.   Its internal face is smooth, polished, and moist-
ened with a kind of humidity which permits  the  blood to flow
through with diminished friction.  In the larger arterial trunks,
some small longitudinal wrinkles are observable  in it; and when
an  artery has been cut through, as in amputation, it is disposed
to  retract in small transverse wrinkles.   It  is, therefore, not
very  extensible, but has,  according to  the experiments of Sir
Everard Home.t a considerable degree  of solidity and strength.
   Ossifications of this membrane are very frequent after the age
of sixty.

  In addition to the tunics mentioned, cellular substance, vessels.
and nerves enter into the  structure of arteries.
  The Cellular Substance is not abundant, and serves principally
to unite the sides of the circular  fibres to one  another, and to
join the internal to the middle coat.
  The Vessels (Vasa Arteriarum) consist both in arteries and in
veins, and come from the adjacent trunks, instead  of from those
on which they  ramify.  They may be  made very distinct by a
fine injection, or by laying them bare in the living body;  when
in a little time  after exposure, they begin evidently to carry red
blood, and to grow turgid as in inflammation.   The  difference
in the colour of the blood distinguishes  these arteries from  the
same kind of veins.  Both arteries and veins may be traced very
well into the middle toat, but not upon  the internal,  though the
changes which occur in the  latter,  from disease and upon the
application of  ligatures, prove clearly that exhalation and  ab-
sorption are continually going on there.  For in inflamed arte-
ries, an  exhalation is seen  upon their internal surface, and when

  *  Hunter, loc. cit.
  j-  transactions for the Improvement  of Medical and  Surgical Knowledge
vol.  i.
  Vol.  II.—16 
170
CIRCULATORY SYSTEM.
 a  coagulum  has been produced  by ligature, it  is  finally ab-
 sorbed.
    The Nerves of the arteries, according to Wrisberg and Be-
 clard, are numerous and considerable, form around them a plex-
 us resembling that of the par vagum around the oesophagus, and
 follow them into the interior of our organs, with the exception
 of the brain; which has  them only to its surface.   They are
 proportionately more abundant in the aortic than in  the pulmo-
 nary  system;.also upon the smaller than  upon the larger arte-
 ries.  The arteries of the  head, of the neck, of the thorax, and
 of the abdomen, are supplied from the sympathetic nerve, while
 those of the extremities are supplied from the nerves of the spi-
 nal marrow.
   The passing of the blood through the arteries is accompanied
 with  a pulsating motion,  which,  for the most  part,.is exactly
 synchronous with the contraction of the left ventricle, and de-
 pends upon an increased quantity  of blood  thrown into them at
 the moment.   The dilatation of the artery may be both seen and
 felt:  "but were we to judge of the real increase of  the artery
 by this, we should deceive ourselves;  for when covered by in-
 teguments, the apparent effect is much greater than  it really is
 in the artery itself; for in laying such an artery bare,  the nearer
 we come to it, the less visible is its pulsation; and, when laid en-
 tirely  bare, its motion is hardly either to be seen or felt.  This
 apparent diastole of the artery is augmented in proportion to the
 solid matter covering it, whence  tumours  over large arteries
 have considerable motion given to  them, and have often been
 supposed to be aneurismal.  Arteries, in fact, during  their dias-
 tole or dilatation,  increase  much more  in length than in width,
 and are thrown into  a  serpentine  course: instead, therefore, of
 the term diastole, it should rather be called the elongated state."*
 Mr. Parry, of Bath,f has denied  that the arteries dilate at all
 during their diastole: his  opinion  however, is peculiar, though,
 in an experiment performed  some years ago upon the carotid
 artery of a calf, its correctness appeared to me then to be fully
proved.
  There is no part of the human body which presents more fre-
quent varieties, in different individuals, than the arteries.  These

 * J. Hunter, loc. cit.  f Experimental Inquiry en the Pulse, 1816—1819 
TEXTURE OF THE VEINS.
171
varieties are found, in their place and manner of origin, in posi-
tion, and in the number of their ramifications.   They are com-
paratively rare in the trunks of the first order, more common in
those of the second, and still more usual in those of the third and
fourth.  From these causes, discrepancies are continually found
in the descriptions of the most approved authorities, and must
last so long as writers repose upon a partial experience, instead
of referring to what  has been most generalty observed.
                    CHAPTER  III.


              OF THE TEXTURE OF THE VEINS.

  The veins, from their duty of receiving the blood in all parts
of the body from the extreme arteries, and returning  it to the
heart, by successively collecting it into the two venae cavas, may
be more appropriately compared to the  roots of a tree, than to
its branches.  The variations in them, as well as their anasto-
moses, are more frequent than in the arteries.
  They are more numerous than the arteries;  for, in addition
to two venous trunks  attending each artery wherever the struc-
ture of the part is intended for locomotion, as  in the extremi-
ties, and in some places upon the trunk of  the body, there is a
very abundant class of veins which are superficial or subcuta-
neous, and which, when  filled properly with injecting matter,
form a fine vascular network over the whole surface of the body.*
These superficial veins, in some places, form trunks even larger
than such as attend the arteries, and especially in the extremi-
ties. Besides the excess in number, the veins which attend the
arteries (Vence Comites) have a capaciousness which, in  many
cases, is double that of the latter.  From these  several circum-
stances, it results that the area of the venous system vastly ex-
ceeds that of the arterial.
* Pauli Mascagni Anatom. Univers. Pisis, 1823, 
172
CIRCULATORY SYSTEM.
   In some cases the veins follow precisely the course of the ar-
 teries, one for one, as in the greater number of the viscera of
 the abdomen, where they have common points of entering and
 departure. Sometimes two arteries discharge into one vein, as
 in the penis, the clitoris, and the  umbilical chord; sometimes
 they pursue a course entirely different from the arteries, as in
 the pia mater.   For the most part they are less tortuous  than
 the arteries.
   The  veins, when injected, assume  a cylindrical shape, yet
 they differ materially from the arteries, in having much thinner
 coats, and in being so pliable that they collapse by their own
 weight.   In the lower extremities, however, near the feet and
 upon them, as the veins sustain the pressure of a long column
 of blood,  they have additional thickness and strength, so as to
 approximate them more to the arterial structure. This provision
 will be found occurring in most places  where they have much
 duty to perform.
   " They are similar to the  arteries in their  structure,  being
 composed of an elastic and muscular substance; the  elasticity
 preserves them in some degree in  a middle state, although not
 so perfectly as  it does  in the arteries.  The muscular power
 adapts the veins to the various circumstances, which require
 the area to be within the middle state, and assists the blood in
 its motion towards the heart."*

   The External Coat is thinner and not so strong as that of the
 arteries; in other respects, the resemblance is sufficiently close
 not to require any particular comment.

  The Middle Coat, near the entrance of the larger veins into
 the heart, is distinctly muscular.t It is formed of soft extensible
fibres, many of which, when the  vein is held up to the light, ap-
pear longitudinal, while the most internal are circular: there are
difficulties, however, in the separation of these fibres, which pre-
vent their course from being accurately ascertained.  Bichat
and Meckel assert, that the whole of them are longitudinal, and
that there are none circular.
  This coat, in the human subject,is much thicker in the system

           * Hunter, loc. cit.           t Beclard, loe. cit. 
TEXTURE OF THE VEINS.
173
of the ascending than of the descending cava;  it is also thicker
in the superficial than in the deep-seated veins.  In some sub-
jects it is much better developed than in others.  In certain parts
of the body it is entirely deficient, as in the sinuses of the dura
mater, and has its place supplied by this membrane; the same
deficiency exists in the sinuses of the bones.

   The Internal Coat is  more delicate  and  extensible than the
corresponding one of the arteries, is less liable to rupture, and
less disposed to ossification.  It is  thrown into a considerable
number of duplications, forming valves.  Each valve is of a se-
micircular shape; is connected by its convex edge to the vein,
while the straight edge  is loose, and turned towards the heart.
When the veins are injected backwards, these valves  may be
forced in the larger trunks, and give them a knotted appearance.
The valves are commonly in pairs, but in certain veins, as the
crural and the iliac, there are three of them together; very rare-
ly do they amount to four.   In some  instances there  is but a
single one; this arrangement is more frequent at venous orifices,
as the great  coronary vein of the heart, the vena cava ascen-
dens, the vena azygos.  They are frequently found  reticulated
as if they had been lacerated, whence it has been supposed that
the fibres which cross the sinuses of the dura mater  are an ele-
mentary approach to them.
   The valves are more abundant in the superficial than in the
deep-seated veins, but they do not exist every where. There are
none in the branches of the  vena portarum, excepting the vasa
brevia: none  in the spine,in the umbilical vein, the cervical veins.
the .kidneys,  womb, ascending and  descending cava, or in the
median vein.   The valves are proportionately more abundant in
the lower extremities.

   From the tenuity of the parietes of the veins, the  blood may
be readily distinguished circulating through them.  Their coats,
like those of  the arteries, are .vascular, or have the vasa vaso-
rum.   The arteries come from the  nearest small trnnks, while
the corresponding veins do not empty immediately, but second-
arily, into the trunk, whose parietes they supply. They are well
furnished with veins.
  Their elasticity, both  transversely and longitudinally, is well
                            16^ 
174
CIRCULATORY SYSTEM.
marked; but they are not so extensible in the latter direction as
the arteries, while they are more so transversely. There can be
no doubt of their spontaneous  powers  of contraction, for it is
abundantly proved by their diminishing much in volume upon
the  application of cold; moreover, when a venous trunk, dis-
tended, with blood, is intercepted by  two ligatures, and then
punctured, it empties itself entirely and rapidly.
   The circulation in  the veins is produced, in a principal degree,
by the contraction of the heart; their own contraction may also
favour this motion, as well as lateral pressure from contiguous
parts.  As the movement of the blood in the smaller arteries is
so uniform as to be almost without pulsation, so the latter disap-
pears entirely in the  veins.  It is not clear that this circumstance
depends exclusively on the friction experienced by the blood in
passing through the capillaries, but is probably rather owing, as
Mr. Hunter has suggested, to the veins receiving their blood from
different arteries,  some of whose channels are more circuitous
than others, and,  consequently, their  blood  arrives at different
times. The momentum of the heart, then, even if it did impinge
upon those channels,  would not be synchronous upon the venous
trunk, but  would be divided in such a way as to produce a tre-
mour or confused motion. The larger veins, however, have near
the heart  a pulsation  during  the contraction of the auricles,
arising from  the  arrest  of their circulation at the  moment.
During inspiration, the vacuum created in  the thorax hurries
on the blood to the heart, but  in  expiration  it is somewhat im-
peded.*

   It has sometimes  happened,  that a large vein near the heart
being opened by an accident or an operation, a strong inspira-
tion  has caused the introduction of air, which, being carried to
the heart, has produced instant death.   It lately occurred in Pa-
ris to the celebrated  surgeon Dupuytren.
                        ▼
  * This ancient  observation has lately been renewed, with additional interest
and details, by M. Barry of Paris.   See a  Report of MM. Cuvier and Durneril,
concerning the Influence of the Atmosphere on the Circulation of the Blood, in
the Philadelphia Journal of the Medical and Physical Sciences, July, 1826.  M.
Barry has probably assigned too much importance to this influence, as it is cer-
tain that the circulation may go on very well where no vacuum is produced at
intervals in the thorax; for example, in the fetus, in incubation, and in fish. 
THE BLOOD.
175
                    CHAPTER IV.

                      OF THE BLOOD.

  The Blood, in the human subject, and in many animals, is of
a red colour.  It is about the consistence of thin size, has a pe-
culiar smell, a nauseous and slightly saline taste, and is some-
what heavier than water; its specific gravity being about 105,
and its temperature in the living body is from 96 to 98° of Fah-
renheit.  Its quantity is variously estimated at from eight to one
hundred pounds, so that there would seem to be no very  exact
means of ascertaining  this point.
   So long as it continues to circulate, or while it is still flowing
from an opened vessel, it  has, to  common inspection, the  ap-
pearance of a homogeneous fluid;  yet, after it has been drawn a
few minutes, and permitted to remain at rest, it assumes a thick
gelatinous condition, expressed by the term coagulation, and by
which it ceases to be any longer fluid.  The coagulation begins
on the surface of the mass, and by a thin pellicle, which shows
itself in three or four minutes;  commonly at the end of twenty
minutes  the coagulation is complete throughout, but this rule
varies according  to the state of the body at the moment; and
the coagulation is more protracted when the  quantity of  blood
is large and has been drawn through a large orifice, than where
it is small, and has been evacuated  through a small orifice.  This
change  has scarcely taken place,  when a spontaneous separa-
tion follows, whereby it is resolved into a watery part called Se-
rum, and into a thick condensed mass called Cruor or Crassa-
menturn.  The serum first shows itself on the surface of the co-
agulum, in small drops,  which quickly increasing in number and
size, finally run together, and form a  mass  of fluid exceeding
considerably that  of  the crassamenturn.   The separation into
serum and crassamenturn, though sufficiently evident  after a
fewr hours, yet requires some days for its complete accomplish-
ment; for the coagulum still continuing to contract, expels  more
and more of the serum.
  The peculiar complexion of the blood depends upon a red co-
louring matter consisting in globules.  This matter does not seem 
176                 CIRCULATORY SYSTEM.
to be an indispensable constituent, as many animals are entirely
deprived of it, and such as naturally are possessed of it, may
have its quantity very much reduced by repeated bleedings. The
colouring matter is generally an ingredient of the crassamentum,
so that the whole of the latter has a red appearance; yet there
are some conditions of the body in which a spontaneous separa-
tion of it takes place, more or less completely.  For example, in
inflammatory diseases the blood does not coagulate so soon as in
health; and the red globules, from being naturally heavier than
the other constituents of the crassamentum, subside to its bottom
and leave it of a white semi-transparent colour.   It is this white
part upon which depends the whole property of coagulating, and
which has been called coagulating lymph.  We have, therefore,
three constituents of blood manifested by its own spontaneous
changes; the serum, the red globules, and the coagulating lymph.
  Coagulation, contrary to popular opinion, is not assisted  by
cold, but rather retarded by it: heat assists it.*   If the heat be
raised to 120°, blood will coagulate five  minutes sooner than if
left at its natural standard, and  even sooner than if its tempe-
rature be reduced to 50°.  If blood be frozen quickly, before it
has time to coagulate, on  being thawed  it returns to the fluid
state, and will coagulate afterwards.   The contact of air does
not produce coagulation.  The late  Dr. Physick, in order to
ascertain this point conclusively, took a  glass tube, which had
a stop cock at each end, and attached one of its ends to the vein
of a dog.  A current of blood was then conducted through the
tube, and while it was flowing, the far stop cock was closed,
and immediately afterwards the other; thus, a column of blood
was obtained which had not touched the air.  After permitting
it to remain a proper time, the tube was broken  asunder, and
the blood found coagulated as usual.  Rest is not indispensa-
ble to  the process, for blood, if shaken  in a vial, will still co-
agulate.   The division  of the blood into small  masses expe-
dites coagulation.  Therefore when  it flows  slowly from the
blood vessels, falls  from some height, or runs  for a distance
over the surface of a dish, it coagulates sooner than under op-
posite circumstances.  The latter are then auxiliary to the blood
manifesting the sizy coat, one of the concomitants of inflam-
* Hunter on the Blood. Hewson. 
SERUM OF THE BLOOD.
177
mation;  because if the coagulation be very rapid, it will pre-
vent the constituents of the crassamentum from separating from
one another, by entangling the red globules, in the coagulating
lymph.
  After death  the blood is coagulated in the veins, though not
so perfectly or generally as  is supposed, for there are no sub-
jects which do not  bleed from their large veins, when the latter
are opened.
  There are many modes of death which prevent entirely the
coagulation of the  blood in the vessels, for example,  where life
is destroyed by a paroxysm of excessive anger; by electricity;
by lightning;  by a  blow upon the stomach; by certain fevers
of a  typhoid  character.  Many chemical articles prevent its
coagulation on being mixed with it.
            SECT. I.—OF THE SERUM OF THE BLOOD.

  Serum is common to the blood of all  animals, and is consi-
dered, by Mr. Hunter, to be more abundant in such as have red
globules.  It is, generally, of a lighter specific gravity than the
crassamentum.   I have, however, often seen the latter floating
in it, which shows the contrary in some instances.  Though its
separation commonly depends upon the coagulation of the lat-
ter, yet that process is not indispensably necessary, as was once
witnessed, by Mr. Hunter, in  a lady, in whom the serum was
disengaged from the crassamentum, while the latter was yet
in a fluid state.  The phenomena of dropsy, also,  prove the
same point.
  Serum, though very fluid, is not so much so as water.  It is of
a light yellow or straw colour, varying,  somewhat, in different
subjects.  It contains a large quantity of albumen, or  matter re-
sembling the white of an egg.  It also consists of water, of soda
uncombined, and of some of  the salts of soda, the presence of
all which may be manifested  in  several ways.  For example.
when exposed to a heat of 140  degrees of Fahrenheit, it becomes
opaque, and at 160 or 165 coagulates firmly.   During this pro-
cess, a great deal of air is disengaged from it.  It is also coagu-
lated by spirits  of wine, by all the mineral acids, by corrosive
sublimate, and by many other articles, all of which  prove the 
178.
CIRCULATORY SYSTEM.
presence of albumen.  Mr. Brande considers this liquid albumen
as an albuminate of soda, with an excess of its  base, and that
its fluidity depends on the excess of soda; when, therefore, the
latter is removed  or neutralized by an  acid, the albumen co-
agulates.  Under the action  of  the Galvanic pile, like the in-
fluence of heat, the soda produces mucus, by blending with  a
part of the albumen; and the remainder  of the latter, not being
able to retain its fluidity after the abduction of the soda, co-
agulates.
  This mucus is, probably, the part which Mr.  Hunter speaks
of as retaining its fluidity when other portions of the serum are
coagulated by heat.   It is observed in meat either roasted or
boiled, and  comes  from it as a thin, limpid fluid, somewhat
tinged  with the  red globules.  The  older  the  animal is, the
greater is its comparative quantity:  in lamb, there is scarcely
any of it, whereas, in mutton five or six  years  old, it is abun-
dant; the same rule seems to  hold in regard to the human sub-
ject.  This  serosity,  or mucus, is coagulable  by Goulard's
Extract.*
   The serum is not always transparent, but sometimes wheyish
and thin:  when it settles, it often throws up a white scum like
cream.   This  more frequently  occurs  in  pregnant  women,
though it is not confined exclusively to either sex, or to any
known condition of body.   The specific  gravity of the globules
composing this scum varies;  for though it generally floats on
the surface of the serum, it does not always: it  also sometimes
swims, and, on Other occasions, sinks in water.  It has been
erroneously considered as chyle not yet assimilated, or as ab-
sorbed fat or oil.   It is, probably, this substance which pre-
sents itself under the form of microscopic globules in the co-
agulum of serum; and, when serum has  been kept for several
days, is deposited in the form of globules at its bottom.   These
globules present a singular motion of ascent and descent in the
serum;  upon the application of heat to it by holding it in the
hand.  It is said  that albumen, coagulated, presents a very
close resemblance to fibrine.f
   The presence of soda uncombined in the  serum, is readily
ascertained by an  infusion of red cabbage, (Brassica oleracea,)
* Hunter, loc. cit,
t Beclard, loc. citt 
COAGULATING LYMPH OF THE BLOOD.
179
or the juice of the flag, (iris versicolor,) which are both made
green by it.  Sulphur combined with ammonia,  is also found
in it.  Owing to the presence of sulphur, serum  has the effect
of blackening silver .when left in it, and also has its power of
dissolving the oxydes of mercury,  iron, copper, and other me-
tallic preparations.


     SECT.  II.—OF THE COAGULATING LYMPH OF THE BLOOD.

  Coagulating lymph, or fibrine, when circumstances are suita-
ble for collecting it, freed from the red globules,  offers the ap-
pearance of a semi-transparent body of a very light drab colour;
it is elastic and strong, and, when subjected to the microscope,
has the appearance  of muscular fibres, by being  composed of
colourless globules.   Like muscle,  it  also, when  macerated in
water, resolves itself into those globules before it  putrefies.
   If the blood, while flowing from an animal, be collected, and,
at the same  moment, stirred round  and round  with  a rough
stick, the fibrine  will gather upon the latter in a fibrous form,
so as to resemble a mass of entangled and knotted packthread.
The fibrine maybe afterwards washed almost  white, and, at
any rate, so as to clear  it entirely from the red globules.
   The fibrine, when dried, loses greatly in its bulk and weight,
by the evaporation of the serum from it, so that the proportion
which it seems to bear to the whole mass of blood is much less
considerable than one would suppose from seeing it in the sim-
ple coagulated state.
   The coagulating lymph of the blood being common, proba-
bly, to  all animals,  while the red  particles are  not, we must
suppose it from this alone to be the  most  essential  part;  and,
as we find it capable of undergoing, in certain circumstances,
spontaneous changes, which are necessary to the growth, con-
tinuance, and preservation of the animal; while to  the  other
parts  we cannot assign any such uses, we have  still more rea-
son to suppose it the most essential part of the  blood in every
animal."*
* Hunter, loc. cit. 
180
CIRCULATORY SYSTEM.
         SECT. III.--OF THE RED GLOBULES OF THE BLOOD.

   The particles of blood upon which its red colour depends are,
 by a majority of observers,  considered  to  be globular, and
 while the blood circulates they float about in the lymph and
 serum.  They are of the same size in animals of the same spe-
 cies, and have no tendency to run into each other,  as globules
 of mercury would.  They are plastic, by which they can as-
 sume an elliptical  shape when they circulate  through vessels
 of a very small size.
   According to the microscopical observations of  Mr. Bauer,
 each globule is one two-thousandth part of an inch in diame-
 ter, but Capt. Kater does not consider it to exceed one five
 thousandth part of an inch.*   There  seems, however, to  be a
 great uncertainty in these estimates of form and of size,  inas-
 much as different observers do not agree among themselves.
 Father Delia Torre considered them as flat  circles or rings,
 with a  perforation in the  centre,  while  Mr. Hewson,  in
 ascribing the same shape, represented them  as hollow  or  vesi-
 cular, with a red dot in the middle.  Mr. Bauer, on  the contra-
 ry, considers that the dot, or colouring matter of the globule,
 is placed upon its periphery.   As  the colour is supposed to de-
 pend upon particles of iron, Dr. John Mason Good  has  wittily
 suggested, that, according to Mr.  Hewson, we have the wheels
 of life  moving  upon iron axels, whereas, according  to  Mr.
 Bauer, they only have iron tiers.t
   It has been observed that the red globules are the heaviest
 part of the mass of blood, and are, therefore, always disposed to
 subside to the  bottom of the crassamentum, though from the
 quick coagulation of the latter, they can seldom do it before they
 become entangled in it, and thereby fixed to a certain  place.
 They do not  invariably retain  their form, but  are readily dis-
 solved in water.  They are, of course, insoluble in serum.  Urine
 does not dissolve them; neither does  a solution of  muriate of
 soda, of sal ammoniac, Epsom salts, nitre,  diluted sulphuric or
muriatic acid: the latter however, deprives them of colour.
   The solution of red globules in water is manifested by the mix-
* Phil. Trans. 1818.
t Study of Medicine, vol, ii. p. 25. 
                  RED GLOBULES OF THE BLOOD.              181

 ture becoming of a fine transparent red, and the process takes
 place almost immediately.   On the contrary, when the globules
 refuse to be dissolved, a muddy mixture is formed.  When they
 are dried in serum, and afterwards soaked again in it, they do
 not resume the globular form.  They have more substance than
 the coagulating lymph, for they do not lose so  much of their
 bulk by drying.
   Notwithstanding the doubts that have been raised on the sub-
 ject, it seems now to be very well ascertained, that iron is the
 colouring principle of the red globules of the  blood, though it
 cannot be detached in the coloured state, owing to the absolute
 necessity of using strong  heat, or concentrated acids to destroy
 the substance with which it is combined.   The iron is an oxide
 with a small quantity  of the sub-phosphate, but a knowledge of
 this fact does not enable the chemist to imitate red globules by
 mixing these chemical substances with albumen.   The process
 by which Berzelius obtains iron from the  blood, consists in
 placing a clot of the latter upon blotting paper, whereby its se-
 rum is absorbed.   The clot being afterwards put into water, its
 colouring matter is dissolved, while the lymph remains entire;
 by removing then the lymph, and evaporating the water, the co-
 louring matter is obtained, which, on being reduced to ashes,
 renders about one  two-hundredth part of its weight in iron.
   The chemists  also inform us,  that fibrine, albumen, and the
 colouring matter, all resemble one another so closely, that they
 are only modifications of one and the same substance; and that
 each of them yields, upon decomposition, phosphate  and car-
 bonate of lime, though these ingredients cannot be detected by
 tests applied to the entire mass of blood.
   "It  is difficut to determine by what means the iron, or the
 sulphur, or the elementary principles of  calcareous earth,  ob-
 tain an existence in the blood.  If these materials were equally
 diffused throughout the surface  of the earth, we  might easily
 conceive that they were  introduced  through the medium of
 food.   But as this is  not the case,  as some regions, like  New
 South Wales, at least, on this side the Blue Mountains, contain
 no limestone whatever, and others, no iron or sulphur, while all
 these are capable of being obtained apparently as  freely  from
the blood of the inhabitants of such regions, as from that of
those who live in quarters where such materials enter largely
  Vol. II.—17 
182
CIRCULATORY SYSTEM.
 into the natural products of the soil; it  is, perhaps, most  rea-
 sonable to conclude that they are generated in the laboratory
 of the animal system itself, by the all-controlling influence of
 the living principle."*
  The red globules, according to the opinion of Mr. Hunter,
 from not being pushed  into the extreme  arteries, where  the
 coagulating lymph  reaches, and from not being found in all ani-
 mals, do not contribute to the growth and  to the repair of the
 system.   But they  seem to  be connected with strength, in such
 animals as have them, as the strength acquired by exercise in-
 creases their proportion and occasions them to be carried abun-
 dantly into parts which previously, from a  debilitated state, re-
 ceived them but partially, if at all.  This fact is well known to *
 graziers, who keep their quantity in certain animals, as veal,
 reduced by quietude and frequent bleeding.
  Their source is not understood, though many conjectures on
 the subject have been hazarded.  Mr. Hunter's opinion  was,
 that  they do not appear to be formed in those parts of the blood
 already produced,but rather to rise up in the surrounding parts;
 as, in the in«ubated  egg, they exist in the form of a zone, com-
posed of dots, previously to the formation of vessels.  This fact
ought to quiet all speculations about their coming from the spleen,
thymus gland, and so on.
* Good, loc. cit. 
BOOK  VIII.
                       PART II.

      Of the Special Anatomy of the Circulatory System.


                     CHAPTER  I.

            OF THE HEART AND PERICARDIUM.

  The Heart, (Cor,) the  centre of the circulation, is situated
in the thorax, between the sternum and the spine; being bound-
ed on its sides by the lungs, and below by the tendinous centre
of the diaphragm.   It is a hollow muscular organ.
  The heart is  of a conoidal shape,  but flattened on the surface
which lies upon the diaphragm.  This flat surface  is on a hori-
zontal line with the lower end of the  second bone  of the ster-
num ; the base  of  the cone is towards the vertebrae, and looks
obliquely backwards to the right side, while the apex is about
the junction of the left fifth rib with its cartilage.  Its common
weight is  about six ounces.   Its greatest length,  to wit, that
from the apex to the base, is about five and a half  inches, four
of which are taken up  by the ventricles: its base is about three
and a half inches in diameter.
  The heart is  divided  into four cavities; two auricles and two
ventricles: the  places where the partitions  are placed between
these cavities are  marked on the surface of the heart by  fis-
sures, sufficiently distinct  to  be  immediately recognised. The
two  auricles form the base  of the heart,  the  ventricles con-
stitute its  body, and  the  anterior end  of  the left ventricle,
by  being extended somewhat  beyond  the right  forms  the 
184
CIRCULATORY SYSTEM.
apex.   The  right auricle and  the right  ventricle, are the two
cavities which are nearest to the right side of the body, while
the left auricle and the left ventricle are  the two cavities near-
est to the left side.  It  will, however, be understood, from the
general observations already made, that  the relative situation
of these cavities is such, that the right ones are in front of the
others, and present obliquely forwards to  the right side, while
those on the left side look obliquely backwards to the left side.
This position of the  heart makes it encroach more upon  the left
cavity of the thorax than it does  on  the right;  from which
cause its pulsations may be very easily distinguished where the
left ribs join their cartilages, while on the right side of the ster-
num there is scarcely  ever  a  perceptible  pulsation.   Being
placed between the  right and  the left  pleura, in the mediasti-
num, it is  surrounded by its own proper capsule  called  the pe-
ricardium.

   The  Pericardium is covered  on its sides by the  pleuras, and
reposes on the  tendinous centre of the diaphragm, to which it
adheres by close compact cellular substance, particularly at its
periphery.  When the latter  attachment is cut through,  a sepa-
ration of the remaiuder is easily effected.   Behind, the pericar-
dium is opposed to the bronchia and the oesophagus.
   The pericardium does not adhere  to the heart, except at the
base of the latter;  it is, therefore, a loose  capsule in, by far, the
greater part of its extent.  It  not only surrounds the heart, but
also the roots of the large arteries and veins connected  with it.
Thus,  it includes the aorta, as  high  up as the great vessels pro-
ceeding from its arch;  from the latter, it  passes to  the trunk of
the pulmonary artery, and also includes it, causing  the aorta
and the pulmonary artery to lie close together.  The posterior
face of these vessels is not covered so  high  up  as  the anterior
face.  The pericardium also invests the  descending vena cava
for an  inch above its junction with the right auricle: it likewise
invests the trunks of the pulmonary veins, and.  the  ascending
cava as it rises above the diaphragm.  The pouches which it
forms at the  base of the heart, in passing from one of these ves-
sels to another, are the cornua of some anatomists.  It cannot
be considered as pierced for  the passage of these vessels, but is
lost insensibly on their parietes;  being continued into the cellu- 
PERICARDIUM.
185
 lar covering of the arteries, in accompanying them to a great
 distance.*
   The pericardium is a double membrane, or  consists of two
 layers, an internal and an  external one.   The external mem-
 brane, to which the preceding description is especially applica-
 ble, resembles strongly  the dura  mater, but  is thinner; it is,
 therefore, white, semi-transparent, fibrous, and inelastic.  Its
 thickness is greater on the sides than below, where it rests upon
 the diaphragm, or above, where it goes along the great vessels:
 its fibres are  irregularly disposed and interwoven, but many
 may be  traced longitudinally.
   The internal membrane lines the external, and gives the po-
 lish to its cardiac surface;  it is then conducted along the sur-
 face of  the several vessels that have been mentioned, to the
 heart, over the whole of which it is spread, and  adheres to it
 by cellular substance, frequently containing much adipose mat-
 ter: it also causes  the heart to have a smooth shining surface.
 This is a very delicate thin serous layer; and secretes a fluid,
 transparent and somewhat unctuous, like that of the joints, but
 not so consistent; which lubricates the surface of the heart and
 permits it to play freely  within its pericardium.   This fluid, in
 a  natural state, seldom exceeds  a tea-spoonful,  though two
 ounces, or a little more, are not considered sufficient evidence
 of a pathological state: its augmentation constitutes a dropsy.
   After  death, we find the pericardium lying loosely around the
 heart, from the vacuity, and consequently diminished bulk of
 the latter; but while the circulation is going on, the heart fills
 and distends it.  A striking resemblance is observable between
 the condition of the pericardium and the moveable articulations.
 Its'external layer  corresponds  with  the  strong fibrous capsule
 that passes from one bone to the other; while the internal is the
 synovial bag,  which scarcely assists in the  strength of  the ap-
 paratus,  but secretes a fluid to  render motion  easy.
   Several instances are  on record of a total absence of peri-
 cardium.                            a

  The Right Auricle (Auricula Dexlra, anterior)  is an oblong
cuboidal  cavity.  It is joined at its posterior superior angle by

               * Sabatier, Trait. d'Anat. vol. ii. p. 284.
                            17* 
186                 CIRCULATORY SYSTEM.

the descending vena cava, and at its posterior inferior angle by
the ascending vena cava. The structure of the auricle, between
these two points, seems to be only a continuation of that of the
veins.   These veins enter with a direction slightly forwards, so
that their columns  of blood are not directly opposed  to each
other.   In front of this continuation of the two  veins, the auri-
cle is dilated into a pouch called its sinus; the upper extremity
of the latter, just in front of the descending cava, is elongated
into a  process with  indented edges, and has some general re-
semblance to the ear of an animal, from which it is probable
that the term Auricle has been  derived.
   The exterior surface of this cavity is smooth and uniform, but
its internal surface is varied at several places.   About midway
between the orifices of the two cavae is found a  transverse pro-
minence, the Tuberculum Loweri, which is  occasioned by the
continuous structure of the veins meeting at an obtuse angle*
This cavity is separated from the left auricle  only by a thin sep-
tum, which  is common  to  the  two auricles.  On the  septum,
below its middle, is a superficial circular depression, the Fossa
Ovalis; it is more distinct above than below, and varies much
in its dimensions.  It is surrounded by an elevated margin, com-
posed of muscular fibres, and  called its Annulus, or the Isthmus
of Vieussens.  The septum  of the auricles is thinner at  the fos-
sa ovalis than elsewhere, and is  frequently perforated by one
or more foramina.   I have, in several  instances, seen a hole
there, large enough to transmit the finger. On  such occasions,
from the valvular arrangement of the opening, it is probable that
the blood of the  two auricles is still  kept distinct.   The fossa
ovalis  always presents this foramen in the foetal state.

  Just  below  the fossa  ovalis is found  the  Eustachian valve,
consisting in a duplication of the lining  membrane of the auri-
cle.   It is crescentic, but varies  much  in its  dimensions and
shape.  Its left extremity commences at the left inferior mar-
gin of the annulus ovalis; it then extends itself along the front
of the orifice of  the ascending cava, where the latter is  con-
nected with the auricle, but never to an extent  sufficient to ar-
rest the circulation  there.   Sometimes  it is reticulated at its
margin, and half an inch wide; on other occasions, it is scarcely
developed.   Its loose edge looks upwards, and to the right side. 
THE HEART.
187
Its office in the foetus is clearly, according to the opinion of Sa-
batier, to direct the blood of the ascending cava through the fo-
ramen ovale.  In the adult, it may, on the general principle of
venous valves, oppose itself to the introduction of refluent blood
into the ascending cava;  but this office cannot be very impor-
tant, as  the valve is frequently scarcely visible at  that age.
  At the lower part of  the  right auricle, just to the left of the
Eustachian valve and very near it, is the orifice of the large co-
ronary vein of the heart: it is protected by a small semi-lunar
valve, (Valvula Thebesii,) formed  also by a  duplication of the
lining membrane of the auricle.  This orifice will  admit a quill
of common size very readily.
  Between the right auricle and ventricle is a round hole, of
more than an inch in diameter, for the passage of the blood; it
is the Ostium  Venosum.   Its margin, on  the auricular side, is
smooth  and rounded.
  The parietes of the  right  auricle are  formed  by muscular
fibres.   On the sinus these fibres are collected into small trans-
verse fasciculi, called Musculi Pectinati, from their resembling
the teeth of a comb.  These fasciculi, though slightly united
by  other fibres, yet leave  between them deep interstices, by
which the external and  the internal membrane of the heart come
into contact.   The parietes of the auricle are about one line in
thickness.  Its muscular structure is continued for a short dis-
tance, on  the  two venae  cavse.  There are several orifices of
small veins on the internal surface of this cavity, and in greater
abundance around the fossa ovalis;  they belong to the system
of coronary vessels, and are the foramina Thebesii.

  The  right  Ventricle (Ventriculus  Dexter, anterior.)  The
general form of this cavity, which receives the blood from the
right auricle, is that of a  triangular pyramid, curved somewhat
backwards, and having its base downwards.  It forms the great-
er part  of the anterior surface of the heart, and is about three
lines in  thickness.   It  is bounded on its  posterior  face by the
left ventricle,  from which it is completely separated by a thick
septum.
  The  internal  surface of this cavity is covered by muscular
fasciculi, of very irregular shapes  and dimensions, designated
under the term of Columnar Carneae ; some of the latter go from 
188
CIRCULATORY SYSTEM.
 one side to the other; others contribute to the mechanism of the
 valvular apparatus between it and the right auricle; but  the
 greater portion is employed in forming a complicated reticular
 texture over the internal face of the ventricle.  Those connected
 with the valve vary from  four to eight in number:  they are
 rounded, of different  lengths and sizes, and detach from their
 projecting extremities several small rounded tendinous chords,
 (chorda; tendinece,) which are inserted into the floating edge of
 the valve.   These chords form  an  intertexture  among them-
 selves.
   The Valve, between the ventricle and the auricle, consists
 in a duplicature of the lining membrane of the ventricle, arising
 uninterruptedly from  around the ostium venosum, at the left
 margin,  which is  there somewhat  tendinous.   This  valve is
 called the Tricuspid, (Valvula  Tricuspis, Triglochis,) because
 its loose margin is divided into three points  or processes.  One
 of these points, which is at  the anterior external  margin of the
 orifice, is much larger than the other two and more distinct  in
 its boundaries.  The edges of these processes form a sort of re-
 ticulated work along with the adjoining ends of the tendinous
 chords: by  this arrangement they are always kept expanded
 and in the cavity of the ventricle.
   The opening for the pulmonary artery is  placed above the
 ostium venosum;  at this point, the cavity of the ventricle,  in-
 stead of being reticulated, is made smooth, for the  more  ready
 transmission of blood.  The orifice of the pulmonary artery is
 round, and about twelve lines in diameter;  it is furnished with
 three valves, called from their shape Semi-lunar or Sigmoid.
 Each valve  is a  semicircular plane,  formed from the  lining
 membrane of the artery, and attached  to the latter by its semi-
 circumference.  The diameter of the plane is loose, and, instead
 of being straight, has each  semi-diameter of a curved or fes-
 tooned shape: in the centre of its edge is a small cartilaginous
 body, the Corpusculum  Aurantii, which, when  the valve  is
thrown  down by the reaction of the artery, comes in contact
 with the corresponding bodies of the other valves, so that they
 serve as  mutual abutments.  The Corpusculum  is  sometimes
 scarcely discernible.  Between  the outer face of  each  valve
and the  artery there is a pouch, attended with  a  slight  dila-
tation of the artery, and called the Sinus Valsalvae.  Between 
The heart.
189
the coats of each valve there is an additional fibrous substance,
for the purpose of strengthening it.

   The Pulmonary Artery, immediately  after its origin, goes
upwards and backwards to the under part of the curvature of
the aorta, and there divides into two trunks, one for each lung.
These trunks  separate widely, and from the middle of their
fork proceeds a ligamentous substance, the remains of the Duc-
tus Arteriosus of the foetus, to the aorta posteriorly to the origin
of the left subclavian artery.  The right Pulmonary artery is
both longer  and larger than the left, and passing transversely
behind the aorta and the descending cava, then penetrates the
substance of the lung to be distributed as  mentioned.   The left
pulmonary artery passes to the lung in front of the descending
aorta. Though the pulmonary artery is quite as large as the
aorta, its parietes are thinner.
   The left Auricle, (Auricula Sinistra, posterior,) in the na-
tural situation  of the heart, is  concealed  by the right auricle
and the ventricles.  Its figure is more regularly quadrangular,
or square, than that of the right, and into each of its angles is
introduced a pulmonary  vein, there being two on  each side.
Sometimes, however, the latter join together previously, so that
the two have but a common orifice.  Its tip, or ear-like portion,
is situated at the left side of the pulmonary artery, and is long-
er, narrower, more crooked, and more notched  at its margins
than the corresponding portion of the right auricle.
   The parietes of this  cavity are muscular, and somewhat
thicker than those  of the right; they are smooth and uniform,
both  externally and  internally, with the exception of its  ap-
pendix or ear-like portion, in which the.musculi pectinati pre-
vail.  The  term sinus venosus  or  sinus  pulmonalis of anato-
mists, only  means that part of the cavity into which the pul-
monary veins empty.  The septum between the auricles, when
viewed on this side, has the place  of the fossa ovalis marked
out principally  by its diaphanous  condition.   Occasionally,
there is  some appearance of  the  valve which  once existed
there.
   At the inferior part of the anterior side of this cavity is found
the opening between it and the left ventricle, also called Ostium
Venosum;  it  is circular, and rather more than an  inch in dia- 
190
CIRCULATORY svstem.
meter, resembling strongly the corresponding orifice  of the
right side of the heart.

  The left Ventricle*. (Ventriculus  Sinister, posterior) jn the
shape of its cavity resembles a long ovoidal or  conical body.
Its parietes are generally three times as thick as those of the
right ventricle, amounting to about eight lines:  it is thicker,
however, at its inferior than at its superior part, as it gradually
decreases in approaching the  aorta.
  Its internal  surface is arranged on  the same principle with
that of the right ventricle, being roughened by the presence of
numerous fleshy columns (Columnce Carnece)  some  of which
are connected with the valvular apparatus between it  and the
left auricle: others form an intricate reticular texture on its
sides, and a few pass from one side to the other.   As this sur-
face approaches the  orifice of the aorta, it becomes smooth,
so that no impediment may be afforded  to the passage of the
blood.

  The Ostium Venosum, on the side of this cavity, has its mar-
gin looking tendinous, and furnished with a duplicature of the
lining membrane that surrounds it.  This duplication, by being
severed on its loose edge into two divisions, obtains the name
of Mitral Valve, (Valvula Mitralis.)   Its margin is secured
from  being pushed into the left auricle  by numerous chordae
tendineae, which are attached by their other extremities to four
or five columnae carneae projecting from the surface of the ven-
tricle.   The whole internal arrangement of this cavity indicates
a great increase of strength over that of the right side: in the
robustness of its fleshy columns, the number and  size  of its ten-
dinous chords, and the greater thickness  of its valve.  The
upper division of the mitral valve is placed immediately below
the orifice of the aorta, and is  considerably broader than the
other, so that  when it opens to admit blood, it is in some mea-
sure thrown over the  aortic  orifice.  There is  less of an in-
tertexture among the  tendinous chords  here than on the right
side of the heart: they cluster more, and, owing to the breadth
of the extremities of the fleshy columns, are more parallel.

   The Septum of the Ventricles is  of considerable  thickness, 
THE HEART.                       191
 being  formed  almost  exclusively  by the continuation  of the
 fibres of the left ventricle.  Where the large columnar carneae
 elevate themselves on its surface, its thickness is increased.
 Its shape is somewhat  triangular.   It forms a round projection
 into the right ventricle, while its other surface, which presents
 to the left,  is concave to the same degree.   It is rather thinner
 as  it  approaches the  auricular septum  than  elsewhere.   Its
 fibres  near  the apex are less closely connected to each other.

  The orifice of  the Aorta is furnished with three  semi-lunar
 Valves,* which, in the mode of their arrangement, correspond
 precisely with those of the pulmonary artery.   They are, how-
 ever, thicker, and the  CorpuscuJa Aurantii are  larger.   The
 Sinuses of Valsalva, attended with a slight dilatation of the ar-
tery, exist in the same way.   Just beyond the margins of  the
 right and of the  left valves  are observed the orifices of the two
 coronary arteries.   The orifice of the  aorta is  somewhat ten-
 dinous, which marks out the distinction of structure between
 it and  the ventricle.


                 Of the Texture of the  Heart.

  The Heart, with the exception of the serous membrane which
 lines its cavities, and of the serous lamina of pericardium which
 covers its surface, consists entirely of muscular fibres.
  The sides of  the  auricles, as stated, are much  thinner than
 those of the ventricles.   In the  right  auricle, the  stratum of

  * Mr. Erskine Hazard has  furnished me with  the following estimate on the
 action of these valves:—
                          If the diameter of the artery be put = 10, the
                        length of the superior edge of the valve will also
                        be 10.  The arc occupied by  the  valve  will be
                        10.47 = 120° of the  circle.  The valves, when
                        open, will either assume the form at B, or that of
                        the double chord of 60°, as at A. In either case
                        being .47 shorter than the arc, they cannot come
                        in  contact with it, and must, therefore, leave room
                        for the blood  to get behind them, and  depress
                        the valves.  For the same reason, they cannot
                        close the orifice of the coronary arteries. The
                        chord of 120° would be 8.67.
 
192
CIRCULATORY SYSTEM.
 muscular fibres  is  uniform in its venous  portion, but  on the
 sinus is arranged into the parallel fasciculi called the Musculi
 Pectinati; a circular fasciculus surrounds the orifice of the de-
 scending cava.  In the  left auricle, the  stratum  of muscular
 fibres forms a uniform  layer,  and is also  thicker than on the
 right side.   These fasciculi commence on the pulmonary veins
 and run transversely across the auricle, with the  exception of
 the more deeply seated, which are irregular, and crossed upon
 each other.   The septum of the  auricles  is  also formed by a
 muscular stratum.
   In the  ventricles, the Superficial fasciculi  observe a spiral
 course, and many of those belonging to the left ventricle may
 be traced over the right; as the fibres are more deeply situated,
 they become shorter  and  more  interwoven.   In the septum,
 between the ventricles, the fibres of the two cavities are much
 interlocked; but, with some trouble, may be partially separated.
 The fibres of the  columnae carnese are too irregular  in their
 course to admit even of a general description.  It would appear,
 however, that they are a continuation of the  superficial spiral
 fibres of the ventricles which penetrate into the interior of the
 heart at its  apex,'and  leave there a  small foramen which is
 closed only  by  the  pericardium, externally, and  the  lining
 membrane of the heart.   M. Gerdy  asserts, that all the fibres
 of the heart  arise from, and  are inserted  into, the tendinous
 rings forming the ostia venosa  and the orifices of  the arteries;
 having in the mean time traversed the course which is peculiar
 to the several fasciculi, according to their being superficial, in
 the middle or deep-seated.*
  All the  cavities of the  heart are lined by a serous membrane,
 resembling that of the blood vessels.


               Of the Blood Vessels of the Heart.

  The Heart is furnished with both arteries and veins, which be-
long to its nutritious system.
  The arteries, called Coronary, arise, as  observed, from  the

  * For a very detailed exposition of the structure of the Heart, see Wolff Act.
Acad. Petrop. 1781; and Gerdy, Journal Complementaire du Diet, des Sc. Med.
vol. x. p. 97. 
                         THE HEART.                     193

 trunk of the aorta, somewhat above the margins of the semi-
 lunar valves;  so that when the latter are applied  against the
 aorta, the orifices of these arteries are still visible.

   The Right Coronary Artery begins above the anterior valve,
 and passes to the right, beneath the pulmonary artery;  it  then
 shows itself in the upper part of the fissure, between  the right
 auricle and right ventricle, and follows the course of this fissure
 to the flat side of the heart.   It detaches, as it goes along, se-
 veral small branches, which  come  off at right angles from it.
 One set of these branches  is distributed upon the right ventricle,
 and another set upon  the right  auricle.   Small branches are
also sent from it to  the root  of the pulmonary artery, and to
that of the aorta.

  The Left Coronary Artery begins above the left  semi-lunar
valve.  While  its root is still obscured by the pulmonary artery,
it divides into two principal branches, of which the anterior runs
in the fissure on the upper part of the septum of the ventricles
to the apex of the heart, and in this course distributes branches
to the right and left ventricle: those to the right anastomose
with the branches of the  right coronary artery, which go to
the  same ventricle.  The other branch goes along the groove,
on the septum, between the left auricle and left ventricle, and
reaches the under surface  of the heart; and in this  course dis-
tributes many branches to the left auricle and left ventricle,
both on their upper and under surfaces.  It  anastomoses freely
 with the branches of the trunk that run along the upper part of
 the septum.

  In consequence of the frequency  of the anastomoses between
 the two coronary arteries,  injecting matter  thrown into one
 very readily finds its way into the other.

  The Coronary Veins receive the blood, which is distributed
 by  the coronary arteries through the substance of the heart.

  The Great  Coronary Vein (Vena Coronaria Maxima Cordis)
 is formed by the union of several  trunks, which  run from the
 apex towards  the base of the heart.  One of them  begins  at
   Vol. II.—18 
194
CIRCULATORY SYSTEM.
the apex, goes  along  the  superior fissure of the  septum of the
ventricles, and  then winds to the left side, between the left au-
ricle, and the left ventricle: while in the latter position, it is
joined by several trunks coming from the left ventricle and the
left auricle: it, finally, empties into the lower part of the right
auricle, just in  front, as mentioned, of the orifice of the ascend-
ing cava; being there covered by its own valve.

  The Lesser  Coronary Vein (Vena  Coron. Minor  Cordis)  lies
in the inferior  fissure of  the septum  of the ventricles.  It  be-
gins at the apex, arid, going backwards, collects the blood from
the flat surface of the heart, principally on the right ventricle.
It discharges into the great coronary  vein, just before the latter
terminates in the auricle.

  Besides the preceding veins, some of a  smaller size exists on
the right ventricle and auricle, and about the root of the aorta
and pulmonary artery, and empty by several  orifices into the
right auricle.   There are also some veins of a still smaller
size, which  open into all the cavities of the heart by little ori-
.fices, called the Foramina of Thebesius: by Mr.  Abernethy
they are considered  as being larger when the lungs are  dis-
eased.*

   The Nerves  of the Heart come principally from the cervical
ganglions of the sympathetic, and follow the course of the coro-
nary arteries.  It has been  doubted  whether these  nerves are
actually distributed in the substance  of the heart, from the  pre-
sumption, that  as they cannot be traced beyond the third order
of  branches of the coronary arteries, they are limited to them.
But, as the ramifications of the sympathetic are bestowed exclu-
sively upon the branches  of the circulatory system, Meckel has
very properly suggested, that the heart being also supplied with
nerves from the same source, it follows that there can be no de-
parture from the general  rule, as the  heart is nothing more  than
the fibrous portion of the blood vessels more  completely deve-
loped.
    V\ hile the circulation continues, as both auricles contract at
" London Philosophical Transactions, 1798. 
            BRANCHES FROM THE ARCH OF THE AORTA.         195

the same instant, whereby the blood is thrown into the ventri-
cles, and as immediately afterwards the ventricles contract si-
multaneously also, whereby the blood is forced into the aorta and
the pulmonary artery, so it is the contraction of the ventricles
which causes the heart to strike  against the parietes of the tho-
rax.  For, as was first pointed out fey Dr. W. Hunter, the blood
which is forced through the large arteries, by extending them
diminishes their  curvature, or brings them more into a  straight
line, in which effort the heart bounds up from the tendinous cen-
tre of the  diaphragm.  The filling of the auricles, while this is
going on,  also assists  in protruding the heart forwards.  The
French anatomists assert, that during the contraction of the ven-
tricles, their extremity is elevated or bent upwards on the body
of the heart, which will also increase the momentum of ihe stroke
against the thorax.
                    CHAPTER  II.

                     OF THE ARTERIES.

  SECT. I.--THE AORTA AND THE BRANCHES FROM ITS CURVATURE.

   The Aorta is the trunk of the arterial system.  Having arisen
from the  superior posterior end  of the left  ventricle, its root
passes beneath the pulmonary artery, and is entirely concealed
in front by it.  Keeping to the right, it emerges at the base of
the heart, between the right auricle and the trunk of the pulmo-
nary artery, being bounded on the right side by the descending
cava.  Continuing its ascent, it forms a curvature with the con-
vexity upwards, and the summit of which rises to within eight
or twelve lines of the superior edge of the sternum.  This cur-
vature is in front of the third and fourth dorsal vertebras, and its
direction is nearly marked out by a line drawn from the anterior
extremity of the third right rib, to the posterior end or tubercle
of the third one on the left side.   In this course, therefore, the 
196
CIRCULATORY SYSTEM.
aorta passes over the  right pulmonary artery, across the left
bronchus, and applies  itself to the left side of the spine, about
the third or fourth dorsal vertebra.   It is this curvature which
obtains the name of the Arch  of the Aorta, (Arcus Aortoz.)
   Near its origin, where the aorta is still within the pericardium,
it  has very commonly, especially in  persons advanced in age, a
dilatation, which is called the great sinus to distinguish it from
the lesser sinuses, or those of Valsalva.    This dilatation is use-
ful in diminishing the  resistance  arising  from the curvature of
the aorta,  to the current of blood,  or rather it is a  provision
for doing away with the effects of this friction, as by it a larger
current of blood becomes a compensation for diminished velo-
city.  The ascending portion  of the arch is to the right of the
vertebral  column, the  descending portion to the left, and the
middle or horizontal part goes in front of the  trachea.
   The aorta, in its descent  down the thorax, is placed in the
posterior mediastinum, and  is covered on one side by the left
pleura, while the other side is in contact with the left surface of
the bodies of the dorsal vertebrae.   At  the  lower part of the
thorax it inclines  towards the middle line of the vertebrae, in
order to reach  the  hiatus aorticus  of the diaphragm, through
which it penetrates to the  abdomen.  In the  abdomen it de-
scends in front of the lumbar vertebras, somewhat on  their left
side;  and at the intervertebral space between  the fourth and
fifth vertebra? of the loins, or somewhat above it, it ceases, by
being divided into two large trunks, the  Primitive Iliacs;  one
for each lower  extremity, and the  corresponding  side of the
pelvis.
   In this course of the aorta, from the heart to the loins, it first
gives  off" the branches which supply the head and the superior
extremities: then, those which supply the sides of the thorax; af-
terwards in the  abdomen, it detaches the trunks which supply
the viscera and  the sides of the latter cavity.
   The Coronary Arteries are, strictly speaking, the first  branches
of the aorta, but as they belong especially to the heart, their de-
scription is associated with it.  In all the space  between them
and the superior convexity of the aortic  arch no branches are
given off;  but as the aorta is crossing the  trachea three conside-
rable trunks arise from it, which  are distributed upon the head
and the upper extremities principally.  They are, the Arteria 
              BRANCHES FROM THE ARCH OF THE AORTA.        197

  Innominata, the Left Primitive Carotid, and the Left Subcla-
  vian.
    The Arteria Innominata  is  first in its origin:  in  ascending
  from left to right in front of  the trachea, and behind  the trans-
  verse vein, it crosses the trachea very obliquely; is from an inch
  to an inch  and a half, and sometimes, though rarely, two inches
  long, when it divides into the right subclavian and the right pri-
  mitive carotid.  The left primitive carotid arises from the aorta,
  close upon the left border of the innominata; frequently, indeed,
  from a part of it.  The  left  subclavian, though  at  its origin
  near the left carotid, generally leaves a distinct interval of one,
 two, or three  lines.   The relative situation  of these trunks is
 particularly alluded to in the  account of the  superior mediasti-
 num.  The two Jasjt are, of course, longer than the correspond-
 ing trunks of the right side, by the whole length of the arteria
 innominata.  With the exceptions connected  with their mode of
 origin,  the  arterial trunks of  the two  sides  are  exactly alike,
 and have the same mode of  distribution

   The  Common Carotid  Artery  (Carolis Primitiva) being  a
 branch of the innominata on the right side, and of the aorta on
 the left, goes up the neck to terminate just below the cornu of
 the os hyoides.   In the early part of its course, the right one is
 more inclined outwardly than the left, owing  to its origin from
 the arteria innominata in front  of, and  to the right side of the
 trachea; whereas, the left ascends almost vertically.
   At the lower part of the neck, just above  the  sternum and
 the clavicle, the carotid is covered by the sterno-hyoid and thy-
 roid  muscles, and by  the  sternal portion of the sterno-cleido-
 mastoid.  It is crossed obliquely on a line with the lower part
 of the thyroid cartilage of the larynx, by the omo-hyoid muscle.
 It lies at the side of the thyroid gland, the trachea, the larynx.
 the oesophagus, and pharynx, in front  of the transvcr. e processes
 of the cervical vertebrae, and the  longus colli muscle; having
 on its outer margin, but somewhat in front, the internal  jugu-
 lar  vein, and the pneumogastric nerve  enclosed  in the  same
sheath, and the sympathetic nerve behind.  At the side of the
 larynx, the caroled is very superficial, and, with the exception
of being crossed by the omo-hyoideus muscle,  it is only covered
by the platysma myodes and the integuments.
                               18* 
198
CIRCULATORV SYSTEM.
  The Carotid having got as high  as the space between  the  os
hvoides and the thyroid cartilage,  but varying slightly in differ-
ent subjects, there  divides into  two large trunks, the Internal
Carotid, which goes to the brain and to the eye; and the Exter-
nal Carotid, which  is principally distributed upon the more su-
perficial parts of the head and neck.   The first of these trunks
is placed behind the other, and bends outwardly at its root: it is
generally the largest in infancy, on account of the proportionate
volume of the brain at that age; it is also swollen at its root, so
as to form a sinus there,  resembling an incipient aneurism.   No
branch, except in the abnormous cases, is given off from the com-
mon carotid between its origin and bifurcation.
        SECT. II.--OF THE CAROTIDS, AND THEIR BRANCHES.

  The Internal Carotid, (Arteria Varotis Interna,) in the adult,
is smaller than the external, and extends from the larynx to the
sella turcica.  It ascends  between the external carotid and the
vertebrae of the neck, being in front of the internal jugular vein,
and having the pneumogastric  nerve at its outer  margin:  as it
gets on a level with the base of the lower jaw, it is crossed ex-
ternally by the digastric and  the stylo-hyoid muscles: it is im-
mediately  afterwards concealed in the subsequent part  of its
ascent by the ramus of the lower jaw.   Having gone along the
most internal or deeply  seated margin of the parotid gland and
the styloid process of the temporal bone, at the side of the supe-
rior constrictor of the pharynx, it then penetrates into ihe crani-
um through the carotid canal of the temporal bone.
   It is slightly flexed between its origin  and the  carotid canal:
just before it reaches the latter, it curves upwards and forwards.
The first part of its course through the  canal is vertical, after-
wards it goes  horizontally forwards;  and to escape from the ca-
nal it has once more to ascend almost vertically, which brings
it  to the posterior extremity of the  Sella Turcica.  On the side
of the Sella Turcica it again passes horizontally forwards through
the cavernous sinus; and at  the anterior clinoid process it once
more ascends, and, having penetrated ihe dura mater, it reaches
the brain.
   In  this passage, through the carotid  canal, it is  attended by 
CAROTIDS, AND THEIR BRANCHES.
199
the upper extremity of the sympathetic nerve, and gives one or
more small branches to the  petrous  bone; it  also gives  a few
branches to the dura mater and to the nerves  about the caver-
nous sinus. But, for the full exposition of the distribution of the
internal carotid, see the arteries of the Brain and of the Eye.

  The External Carotid Artery (Carotis Externa) extends from
the termination of the primitive carotid, to the neck of the lower
jaw.  In the early part of its course, where it is situated in front
of the internal carotid, and between the pharynx and the sterno-
mastoid muscle, it is comparatively superficial, being only enve-
loped by its sheath, and covered by the platysma  myodes and
the skin.  Just above this place it is crossed externally by the
hypoglossal nerve, which detaches the descending branch along
the front of its sheath and of that of the primitive carotid.  Some-
w7hat above this nerve, it is also crossed externally by the digas-
tric and the stylo-hyoid muscle, and lies there on the side  of the
superior constrictor muscle of the pharynx, near the tonsil gland.
About its middle, it is crossed internally by the stylo-glossus and
the stylo-pharyngeus muscle; it then  ascends through the  sub-
stance of the parotid gland, between the  ramus of the  lower
jaw and the  ear, to its  termination.
   Several very important branches are given off from the ex-
ternal carotid; they are as follow:

  The Superior Thyroid Artery (Art. Thyroidea Superior) arises
from the external carotid, about a line above its root, and is dis-
tributed to the larynx and to the thyroid gland.   It goes at first
inwards and forwards on the side of  the larynx, being covered
by the omo-hyoideus" muscle, and by the platysma  myodes; it
then descends under the sterno-thyroideus to the upper margin
of  (he lobe  of the thyroid  gland.   In this course it performs
several flexuosities, of  considerable variety in different  indivi-
duals.
   The Laryngeal Branch comes from it  near  the superior mar-
gin  of the thyroid cartilage; this branch glides in between the
thyreo-hyoid muscle and the middle  thyreo-hyoid membrane or
ligament; after a short course, it penetrates the latter, and is then
distributed in a great number of  small twigs to the muscles and
to  the lining membrane of the larynx.   A small trunk,  either 
200
CIRCULATORY SYSTEM.
 from the laryngeal branch, or from  the thyroid artery itself, is
 spent upon the crico-thyroid muscle, and  traversing the front
 surface of the  middle  crico-thyroid ligament,  anastomoses  with
 its fellow: small twigs  from this branch penetrate to the interior
 of the larynx through  the middle crico-thyroid ligament.  Some-
 times this crico-thyroid ramus  is superior in size to the one
 above, in which case it principally supplies the interior of the
 larynx.
   The  Thyroid  Branch  is  the  continuation of the principal
 trunk; it penetrates into the substance of the thyroid gland, and
 divides into two ramuscles, one of which goes along the poste-
 rior face of the lobe of the gland, and anastomoses with the in-
 ferior thyroid;  the other goes along the upper margin  of the
 gland, and anastomoses with its congener  of  the opposite side.
 The thyroidal artery is split up into a great  many branches in
 the  substance  of the  gland, it also sends small branches  to
 the pharynx, oesophagus, and the little muscles  on the front of
 the neck.

   The Lingual Artery (Art. Lingualis) comes from the external
 carotid at the distance of from six to twelve lines above the su-
 perior thyroid, and goes to  the tongue.  It is concealed  in the
 early part of its course by the digastric and  the stylo-hyoid mus-
 cles;  it  then penetrates the  hyo-glossus muscle just above the
 cornu of the os hyoides, or goes between it and the middle con-
 strictor of the pharynx; it then ascends between the hyo-glossus
 and  the  genio-hyo-glossus  muscle;  advancing forwards, it  is
 placed between.the latter and the sublingual gland, and, finally,
 reaches the tip  of the tongue.
   The lingual artery sends off the following branches.   At the
 root of the tongue  one or  more  trunks arise  from it (Dorsales
 Linguae) which go to the base of this organ, the tonsils, the pa-
 late, and the epiglottis.  A little  farther on, this artery detaches
 another branch,  (Ramus Sublingualis.) which,  advancing be-
 tween the mylo-hyoid  and  the  genio-hyo-glossus muscles, and
 above the sublingual gland, detaches a great many ramifications
 to these parts and to the lining membrane  of  the mouth; it  is
sometimes a branch of  the facial.  The Ramus Raninus, is the
 continuation of the lingual; it advances between  the lingualis
 the genio-hyo-glossus  muscle, to the tip of the tongue,  distri- 
                 CAROTIDS, AND THEIR BRANCHES.            201

buting continually its twigs on each margin, and  ends there by
anastomosing with the corresponding artery of the other side.

   The Facial  Artery  (Arteria Facialis, Maxillaris Externa)
arises  from the external  carotid two or three lines  above the
lingual, and is spent principally on the side of the face below
the eye.   It is  of considerable size, and very  tortuous;  its root
is concealed by the stylo-hyoid and the digastric  muscle, and it
is traversed externally by the hypo-glossal nerve.  It goes for-
ward within the angle of the  lower jaw, and above the  sub-
maxillary  gland, but  very much connected  with  it:  it  then
mounts over the base of the maxilla inferior, at the anterior
margin of the masseter muscle,  and  afterwards  shapes its
course, in  a serpentine manner, to the internal canthus of the
eye, passing between  the muscles and the integuments of the
face.  In this  course, the facial artery sends  off the following
branches:
   As it passes  by the submaxillary gland it sends several twigs
to it: previously it also sends several little branches to the con-
tiguous muscles, as the internal pterygoid, digastric, and so on;
but they are too small to be of much consequence.
   The Submental branch arises, then, on a level with the base
of the lower jaw; it advances forwards under the origin of the
mylo-hyoides, and above the  anterior  belly of the digastricus.
It sends several ramuscles  to these muscles, some  of which
anastomose with the ranine artery; behind the symphysis of the
jaw it anastomoses with  its fellow, it then mounts over the chin,
to which  and  to the lower lip it is distributed, anastomosing
there with the  inferior coronary artery of the  mouth, and with
the inferior maxillary which comes out from  the anterior men-
tal foramen in the lower jaw.
   When the facial  artery has got upon the face, it sends back-
wards  a small branch to the lower part of the  masseter muscle.
Somewhat above this it sends  forwards a  branch called the In-
ferior Labial, which is distributed upon the middle of the chin.
When  it gets on a level with the corner of the  mouth, but some-
times lower down, it sends forward, under the depressor anguli
oris,  the Inferior Coronary Artery, to the lower lip, which fre-
quently supplies the place of the inferior labial entirely; but when
the latter is large, the coronary is small in proportion: a  few 
202
CIRCULATORY SYSTEM.
lines higher up the facial sends forward a third branch, the Su-
perior Coronary, which goes to the upper lip.  These coronary
arteries are very tortuous, and are distributed by many branches
in the substance of the lips: by anastomosing with their conge-
ners of  the other side, they surround the mouth completely.
The superior coronary artery, as it passes under the nose, sends
upwards one or more small branches to the  integuments of its
orifice and septum.
  After this, the facial artery, in ascending towards the internal
canthus of the eye, sends a branch to  the ala nasi, and another
to anastomose with the infra-orbitar artery.  It, finally, termi-
nates at the internal canthus of the eye by anastomosing with
the branches of the ophthalmic, which come out there upon the
side of the root of the nose.   Several  ramuscles, which are too
small to merit  special description, are given by the facial to
the integuments and muscles of the face, and  to  the lower
eyelid.

  The Inferior Pharyngeal Artery (Art. Pharyngea Inferior, as-
cendens) is one of the smallest of the original branches of the ex-
ternal carotid, and generally arises opposite to the lingual; but
there is much variety in the  latter respect, it being  sometimes
higher up or lower down, and not unfrequently a branch of one
of the other arteries, instead  of being an original  trunk.  It
ascends on the side of the  pharynx, between  the  external and
the  internal carotid, and is  covered by the stylo-pharyngeus
muscle.  It is principally distributed  on the constrictor muscles
of the pharynx, and  upon  their lining membrane.  But one of
its branches, called   the Posterior  Meningeal Artery,  ascends
through the posterior foramen lacerum of the cranium, between
the jugular vein and the  pneumo-gastric nerve,  and is distri-
buted on the contiguous dura  mater.

  The Occipital Artery (Arteria Occipitalis) is  a very consi-
derable trunk, which comes from the external carotid, generally
opposite to the facial, and is spent upon the integuments, on the
back part of the head.
  At its  root, it is deeply situated in the side of the neck, below
the parotid gland, and has the internal jugular vein and the par
vagum on its inside.  It goes obliquely backwards, in ascending 
                CAROTIDS, AND THEIR BRANCHES.            203

along the posterior belly of the digastricus between the trans-
verse process of the atlas and the mastoid portion of the tempo-
ral bone, being covered by the several muscles which are in-
serted into the latter, as  the  sterno-mastoid, the splenius,  and
the trachelo-mastoid.   It is covered, for some distance, by the
insertion of the splenius capitis, and becomes at length super-
ficial  at the posterior margin of  this  muscle.   The  occipital
artery is distributed as follows:
  Shortly after its  origin, it sends branches to the  digastric
muscle behind, to the upper part of the sterno-mastoid and to
the lymphatic glands of the upper part of the neck.  While en-
closed by the muscles on the back of the neck, it also sends
branches to them, and anastomoses thereby with the  vertebral
artery;  occasionally, one of these branches is of considerable
magnitude, and has been found descending very low on  the
back, between the splenius and the complexus muscles.  It also
sends a small branch to the  dura mater, through the mastoid
foramen generally, but sometimes through the posterior fora-
men lacerum.  When the stylo-mastoid artery is  wanting, it
also detaches a branch through the stylo-mastoid  foramen to
the internal parts of the ear.
  The occipital artery, having become superficial at  the inter-
nal margin of the splenius on the occiput, ascends on  the latter
bone  towards the vertex in a tortuous manner, sending off, on
each  side, many small ramifications.  It ends by anastomosing
with the posterior temporal artery.

  The Posterior Auricular Artery (Art. Auricularis  Posterior)
arises a little  above the last, at the lower edge of  the parotid
gland, from  the external carotid, and is one of  its smallest
branches.  It ascends backwards enclosed by the parotid gland,
and afterwards between the meatus auditorius externus and the
mastoid bone : at the latter place, it sends a ramification to the
internal side  of the external ear;  it then ascends and is distri-
buted, by small branches, on the contiguous integuments of the
side of the head.   While still  involved in the parotid  gland, it
sends some small ramifications through the meatus  externus to
its lining membrane and the membrana  tympani.   It  then de-
taches a branch through the stylo-mastoid foramen,  from which
the whole artery is also named Stylo-Mastoid;  but this branch, 
204
CIRCULATORY SYSTEM.
as stated, sometimes comes from the occipital.  The stylo-mas-
toid passes along the aqueduct of Fallopius, detaching its arte-
rioles to the tympanum and  to the  labyrinth.
   The External  Carotid having given off these trunks, pene-
trates vertically through the  inner margin of the parotid gland,
and gives to it several small  twigs.  When it arrives on a line
with the neck of the lower jaw, it divides into two large trunks;
one of them, the  Internal Maxillary, goes to  the  parts within
the  ramus of the lower jaw; the  other, being  smaller,  is the
Temporal Artery.

   The Temporal  Artery (Arteria  Temporalis) continues to as-
cend through the  substance of the parotid, but becomes super-
ficial in front of the meatus externus, in mounting over the root
of the zygoma; it is then distributed to the integuments on the
side of the head.
   It frequently  sends off one or two ramifications, of but little
volume, to the  masseter muscle.   Just above its root, and while
surrounded by  the parotid, a branch of  some importance, the
Transverse Facial, (Transversalis Faciei}) leaves it, and crosses,
horizontally, the masseter  muscle, just below  the parotid duct,
sometimes above it.   This  branch is distributed to the adjacent
integuments and  muscles,  and  terminates  in  front by anasto-
mosing with the facial and the infra-orbitar artery.
   A little below the zygoma, the Middle Temporal artery (Art.
Temp.  Media)  comes off  from  the Temporal, and, ascending
with the parent trunk, perforates the temporal fascia at the
upper margin of the zygoma, and is distributed to the temporal
muscle  by many ramifications, which  anastomose  with the
deep-seated  temporal  arteries.  After this, some small twigs,
called Auricular, go to the  external  ear from  the trunk of the
temporal artery.
  The temporal artery, having ascended  for an inch or so be-
tween the aponeurosis of the temporal muscle and the skin, it di-
vides into an Anterior and a Posterior Branch.  The former as-
cends towards the side of the os frontis, and is distributed in
ramuscles to the orbicularis palpebrarum, the belly of the occi-
pito-frontalis, and the integuments of the front of the cranium,
anastomosing with the  frontal artery and the temporal of the
other side.  The posterior  branch is distributed on the integu- 
CAROTIDS, AND THEIR BRANCHES.             205
ments  of the middle of the side of the cranium, anastomosing
with the anterior branch, with  its fellow of the other side, and
with the occipital artery.

  The Internal  Maxillary  Artery (Arteria Maxillaris Interna)
winds  around the neck of the lower jaw, and, passing between
the pterygoid muscles, proceeds in a tortuous manner  to  the
deepest points of the zygomatic fossa.   The first part of its
course is horizontally inwards;  it then ascends in  front of the
pterygoideus externus to the  bottom of  the  temporal bone, or
the spinous process of the sphenoidal: it then passes  forwards,
within the temporal muscle, to the upper part of the pterygo-
maxillary fossa.
  It sends off" several branches, and commonly in the following
order:—

  1. The Arteria  Tympanica, to the tympanum, through  the
glenoid fissure.

  2. The Arteria Meningea Parva, to the dura mater, throuh
the foramen ovale.   It is most frequently a branch of the next.

  3. The Arteria Meningea Magna, or Media, to the dura ma-
ter, through the  foramen spinale.   This branch having entered
the cranium, is  distributed  upon the dura mater in  the manner
marked off by the furrows upon  the internal face of the tempo-
ral, the parietal, and the frontal bones.  One of its branches en-
ters  the  aqueduct  of Fallopius, through  the  Vidian  Foramen,
and  is distributed upon the internal parts of the organ of hear-
ing, anastomosing with the stylo-mastoid  artery.

  4.  The Arteria  Maxillaris, or  Dentalis Inferior, descends
along the internal  face  of the  ramus oPthe  lower  jaw,  and
having sent off some ramifications  of small size to the contigu-
ous muscles and the lining membrane of the mouth, it  enters
the  posterior mental foramen  with the  inferior dental  nerve.
Going along the  canal in the substance of the  lower jaw, it de-
taches  successively from its superior margin ramifications to
the teeth.   At the anterior  mental foramen a  trunk is sent for-
ward as far as the symphysis, which supplies in its course the
  Vol. II.—19 
206
CIRCULATORY SYSTEM.
 canine and incisor teeth; the remainder of the inferior maxi'lia*
 ry artery comes out at the foramen, and supplies the chin, anas-
 tomosing with the facial artery.

   5. The  Arteriae Temporales Profunda? are two in number.
 The first of them, called Posterior, arises next to the inferior
 maxillary.  It is concealed between the external pterygoid and
 the  temporal muscle for some distance;  it then ascends in the
 posterior part of the temporal fossa, beneath the temporal mus-
 cle,  and is minutely  distributed upon  it. The Anterior deep
 temporal artery is separated from the posterior, in  its origin
 from the internal maxillary, by the pterygoid  and the  buccal
 arteries.   It  arises near the  pterygo-maxillary fossa; and, as-
 cending  between the temporal muscle and the fore part of the
 corresponding fossa, it is minutely distributed upon the former,
 anastomosing with the  posterior deep, and with the middle tem-
 poral artery.

   6. The Arteriae Pterygoideae arise after the posterior deep
 temporal.  They vary considerably in regard to number, size,
 and  origin, and are distributed upon the pterygoid muscles, as
 their name implies.  One of their branches, which is sometimes
 an independent trunk from the internal maxillary, goes between
 the posterior  margin of the temporal muscle and of the neck of
 the lower jaw, in front of the latter, to be distributed upon  the
 internal face of the masseter muscle.

  7. The Arteria Buccalis, sometimes a branch of the internal
 maxillary,  but frequently coming from one of its trunks, either
 the alveolar or the anterior temporal, passes along the external
 face of the  upper jaw, and distributes its branches to the bucci-
 nator and zygomatic muscles, and  to the lining membrane of
 the mouth.

  8. The Arteria Maxillaris Superior,  or Alveolaris, proceeds
 downwards and forwards in  winding round  the  tuber  of  the
 upper jaw bone.  It first sends some ramifications through  the
bone to the roots of the great and small molar teeth, and to  the
lining membrane of the maxillary sinus; it then passes forwards 
SUBCLAVIAN, AND ITS BRANCHES.
207
 along the gums, near the buccinator, and gives ramifications to
 them and to the contiguous muscles,

   9.  The Arteria Infra-orbitalis comes from the internal maxil-
 lary, at the upper part of the pterygo-maxillary fossa;  it sends
 some inconsiderable ramifications to the fat and the periosteum
 of the orbit, through the spheno-maxillary fissure.  It then en-
 ters the infra-orbitary canal, and passes through it with the in-
 fra-orbitary nerve.  On arriving near the anterior orifice of the
 canal, it detaches downwards a branch which goes to the ca-
 nine and the incisor teeth, and to the lining membrane of the
 antrum.   It then gets to the face below the origin of the leva-
 tor labii superioris muscle, and is distributed upon  the muscles
 in front of the upper maxilla, anastomosing with the facial and
 with the ophthalmic artery.

   10. The Arteria Palatina Superior descends through the pos-
 terior palatine canal, and, having reached  the mouth,  leaves
 some ramifications with the soft palate:  it then advances be-
 tween the bones and the  lining membrane of the  roof of the
 mouth, and disperses itself in several small twigs; one of which
 passes through the foramen incisivum into the nostril.

   11. The Arteria Pharyngea Superior is sometimes a  branch
 of the last, and is spent upon that portion of the pharynx bor-
 dering on the pterygoid processes.

   12.  The Arteria Spheno-Palatina is the terminating trunk of
 the internal maxillary;  it enters the nose through  the spheno-
 palatine  foramen,  and  divides  into two  branches, which are
 minutely distributed over the  Schneiderian membrane.   One
 of them descends along the septum narium; the other along the
 external  margin  of the  posterior naris,  and divides into two
 principal ramuscles, one of which is dispersed along the mid-           *
 die turbinated, and the other along the inferior turbinate^ bone.


   SECT. III.--OF THE SUBCLAVIAN ARTERY, AND ITS BRANCHES.

  The Subclavian Artery (Arteria Subclavia) of the right side
having arisen from the innominata, and that of the left from the 
208
CIRCULATORY SYSTEM.
 aorta, they each go over the first rib of their respective sides,
 adhering closely to it, in the bottom of the interval between the
 scalenus anticus and medius muscles.   The right subclavian is
 much shorter, and more superficial than the left, from its origin
 to the scaleni muscles.  Near the latter they are each covered
 in front by the sternal end of the clavicle, by the sterno-hyoid
 and thyroid muscles, and by the subclavian vein of the corre-
 sponding side;  behind they are separated from the vertebral co-
 lumn by the longus  colli muscle; below them is the pleura, the
 left artery being in contact with it for its whole passage in the
 thorax; and on their internal side is the primitive carotid.   The
 subclavian of the right side is crossed near the scalenus anticus
 by the par vagum;  the phrenic  nerve  also goes in front of it,
 but on the internal  edge  of the  scalenus.  The subclavian of
 the left side having a course almost vertical from  its origin to
 the interval of the scaleni muscles, is nearly parallel with and
 behind, the primitive carotid of that side; the phrenic nerve has
 the same relative position with it as on  the right side;  but the
 par vagum goes parallel with, and in front of  the  subclavian
 artery, for some distance along the root of the latter.
   At the inner margin of the Scaleni  Muscles  the Subclavian
 gives off"a cluster of trunks; to wit, the Vertebral;  the  Inferior
 Thyroidal; the Superior Intercostal;  the Internal Mammary;
 and the Posterior Cervical Artery.  They sometimes arise dis-
 tinctly, and after the order mentioned: but there is too great a
 diversity in subjects to establish  any rule on these  points.

   1.  The Vertebral Artery (Arteria  Vertebralis)  is the most
 voluminous of the branches of the Subclavian. Immediately af-
 ter its origin it  ascends on  the side of the spine, and enters the
 canal of the transverse processes of the neck at the sixth ver-
 tebra.   Pursuing this course, it gets into the cavity of the cra-
* nium through the foramen magnum occipitis, and is distributed
 to the brain in the manner mentioned  in the description of that
 organ.
   While in the  canal of the transverse processes, it sends  off
 several branches to the heads of the contiguous  muscles, and to
 the medulla spinalis of the neck.  The vertebral  artery, like
 some others, is spindle-shaped, its size augmenting as it recedes 
SUBCLAVIAN, AND ITS BRANCHES.
209
 from its origin; this imparts some advantage to the current of
 the blood.

   2.  The Inferior Thyroid Artery (Arteria  Thyroidea Inferior)
 arises from  the upper face of the subclavian, and goes to the
 thyroid gland.   It ascends at first on the internal margin of the
 scalenus medius  muscle, and  then turns suddenly inwards be-
 tween the vertebrae and the great vessels of the neck.
   In this course several unimportant twigs are sent from it to
 the contiguous parts.   Near its root it detaches  the Anterior,
 or the Ascending Cervical Artery, which going up the neck is
 spent upon the head of the muscles arising from the transverse
 processes, as the scaleni, the longus colli, and so on.  The infe-
 rior thyroidal then gets  to  the thyroid gland, and is very mi-
 nutely distributed to  it, anastomosing with  the other  arteries
 which supply the same organ.

   3.  The  Superior Intercostal  Artery, (Arteria  Intercostalis
 Superior,) arising from the under surface of the subclavian op-
 posite the inferior thyroid, descends across the neck of the first
 rib, and divides into two branches, which supply the two upper
 intercostal spaces:  each of them also sends backwards near the
 vertebra a small trunk to the muscles of the back.

   4.  The Internal  Mammary  Artery  (Arteria Mammaria In-
 terna, Thoracica) descends at first along the interna] margin of
 the scalenus  anticus;  having then got  fairly into  the cavity of
 the thorax, it continues to descend across the posterior face  of
 the costal cartilages, parallel with, and about  nine lines from,
 the outer edge of the sternum,  between the triangularis sterni
 and the intercostal  muscles.
   In this course, besides some distinct twigs  to the anterior me-
 diastinum, it sends a branch (Phrenica Superior) which accom-
 panying the phrenic nerve between the pleura and the pericar-
dium, reaches finally the diaphragm, and is  spent upon it.  At
each intercostal space  which it crosses, the internal mammary
sends outwards a branch, which  is spent upon the fore part of
the intercostal muscles, and anastomoses with the correspond-
in^ intercostal artery: other branches also leave it at each space,
                            19* 
210
CIRCULATORY SYSTEM.
which getting forwards near the sternum, are distributed upon
the pectoralis major, and upon  the  contiguous  muscles.  The
last of these branches, according to M. H. Cloquet, goes trans-
versely across the ensiform cartilage, and, having anastomosed
with its fellow, descends between the peritoneum and the linea
alba to the suspensory ligament of the liver.
   On a  line generally with the anterior extremity of the fifth
rib, the internal mammary divides into two principal branches;
the most exterior of which,  descending along the cartilaginous
margin of the thorax, is distributed in small twigs to  the origin
there of the diaphragm and of the transverse  muscle  of the ab-
domen.   The internal branch reaches the posterior face of the
rectus abdominis muscle, and is dispersed upon it: some of its
branches go as low as the umbilicus, to anastomose there with
the epigastric artery.

   5. The Posterior  Cervical Artery (Arteria  Cervicalis Poste-
rior, Transversa) is of a very unsettled origin, but comes most
frequently either from the subclavian itself, or from the inferior
thyroid.   It is but small in some  subjects, owing to its place
being supplied by branches from the adjoining arteries.
   It crosses horizontally the root of the neck  on the'outer face
of the scaleni muscles above the  subclavian artery.  It gets
under the anterior margin of the trapezius, and is there divided
into two  principal branches; the  ascending one is spent upon
the trapezius and the levator  scapulas; the other descends along
the base of the scapula, and is  spent in ramifications upon the
rhomboidei and the serratus  major  muscles.   Several branches
of minor size  and importance  are  sent off from the posterior
cervical artery to the muscles on the back  of the  neck and
thorax.

  The Subclavian Artery having sent ofFthe preceding  branches,
then escapes from the thorax between the scaleni muscles, and
gets to the arm-pit  between the  first rib and  the subclavius
muscle.   The trunk of it is then continued downwards through
the axilla, and at  the inner side of the  arm to  the elbow  joint.
   From the scaleni  muscles to the elbow  its relative position is
as follows:  When  it first  appears between  the scaleni, it is
bounded above and  behind by the collected fasciculi of the ax- 
AXILLARY, AND ITS BRANCHES.
211
illary plexus of nerves.  In front it is separated from the sub-
clavian vein by  the insertion of the  scalenus  anticus.  It is
placed at the bottom of the depression between the sterno-mas-
toideus and the trapezius, being  covered by the skin, the pla-
tysma myodes, and some  loose  cellular substance below the
latter.  It then descends between the first rib and the subcla-
vius; escapingifrom below the latter, it is covered in front by
the outer margin of the pectoralis major until it reaches the
lower part of the axilla; and  in this course it has the following
relation to  other parts: it passes then under the insertion of the
pectoralis  minor, under the  shoulder joint, then along the in-
ternal face of the coraco-brachialis muscle; it has the axillary
vein in front of it, and the axillary nerves plaited around it as
far down as the coracoid process, when they begin to disperse.
This artery in emerging from the axilla is placed upon the an-
terior face of the insertion of the latissimus dorsi: it then runs
out the length of the coraco-brachialis, and is afterwards con-
ducted along the inner margin of the biceps flexor cubiti and
its tendinous termination;  it lies upon the  anterior face of the
brachialis  internus; and goes beneath the aponeurosis coming
from the tendon of the biceps at the bend of the arm.  In the
arm  it is  concealed only by the integuments and fascia, and
is bordered internally by  the brachial vein and the median
nerve.

   This great trunk of the upper  extremity loses the  name of
subclavian, to be  called Axillary Artery, (Art. Axillaris,)  from
the subclavian muscle to the lower margin of the arm-pit: and
from the latter place to the elbow  joint, it is named Brachial
Artery,  {Art.  Brachialis.)   It  sends  off many  interesting
branches to the  thorax, to the shoulder, and to  the arm;  and,
finally, terminates a little  below or at the elbow joint by bifur-
cating.

            Of the  Branches of the Axillary Artery.

   1.  The   Superior Scapular Artery (Art. Dorsalis  Superior
Scapula) varies  considerably in its origin.  Sometimes it is a
branch of the subclavian, sometimes of the  inferior thyroid, and
it frequently comes from the upper part of the axillary; so that 
212
CIRCULATORY SYSTEM.
 it cannot be referred, with strict propriety, to  any determined
 origin.  When it comes from the axillary, it is very tortuous,
 and has to ascend to its destination, which  removes it entirely
 from any interference with the course of the  subclavian over
 the  first rib, and over  the  upper head of  the serratus  major
 muscle.   But in the other cases, it goes transversely backwards
 and outwards, somewhat below the posterior cervical, and along
 the posterior inferior margin of the clavicle, being covered by
 the sterno-mastoideus, the platysma myodes, and the trapezius;
 consequently, it is just in the  way of the incisions which are
 made for reaching the subclavian artery, from above the cla-
 vicle.
   It reaches the superior costa of the scapula near the root of
 the coracoid process, and passing through  the notch there, is
 distributed, by one large branch, upon the supra-spinatus  mus-
 cle;  and by another, which goes across the  anterior margin of
 the  spine of the scapula,  to the infra-spinatus  muscle.  In its
 course, it sends off several  small ramifications to  contiguous
 parts.

   2. The External Mammary Arteries (Art. Mammariceseu Tho-
 racica Externa) arise from the axillary, between the subclavius
 and  the  pectoralis  minor muscle.  They are  four  principal
 trunks, which go uniformly to certain  parts, but  vary consi-
 derably in their origin;  for sometimes the latter is  distinct in
 the case  of each artery, but frequently otherwise.   Their dis-
 tribution is as follows:
   a. The Thoracica Superior is distributed to the upper part of
 the pectoralis major muscle, and to the pectoralis minor. Some
 of its branches reach the mamma in the female, and anastomose
 with the internal mammary and with the intercostals.
   b.  The Thoracica Longa descends along the posterior face of
 the pectoralis major, between it and  the serratus  magnus.  It
 gives many branches to the lower part of the pectoralis major,
 to the integuments, and, in the female, to the mamma; anasto-
 mosing likewise with  the internal mammary and with the  inter-
 costals.
  c.  The Thoracica Acromialis, immediately after  its origin,
makes for the fissure between the deltoid and the great pectoral
muscle, and divides there into an ascending and a  descending 
AXILLARY, AND ITS BRANCHES.
213
branch.  The former reaches the clavicle, and is partly distri-
buted superficially along it, partly to  the  contiguous  muscles,
and to the shoulder articulation.  The other branch follows the
cephalic vein  along  the interstice between the deltoides and
pectoralis major, and is, finally, distributed  to these muscles and
to the integuments.
   d. The Thoracica Axillaris is irregular, both in regard to the
number of its branches and to their origin.  Instead of a distinct
origin by one or more trunks from the  axillary artery, the
branches belonging to the name of thoracica axillaris, are some-
times derived from the other  thoracic arteries.  They are ge-
nerally distributed only to  the fat  and the  lymphatic glands  in
the axilla.   They occasionally exist primitively as a large trunk,
which runs  on the scapular face of the serratus major the whole
length of the  scapula, and is distributed to the adjacent mus-
cles, and to the fat and glands of the axilla.

   3.  The Scapular Artery (Arteria  Scapularis communis, Sub-
scapulars)  arises from the axillary below  the shoulder joint, at
or near the  anterior margin of the subscapularis muscle.  Giving
off some inconsiderable branches to the lymphatic glands of the
arm-pit, it descends along the anterior margin of the subscapu-
laris, and is distributed to  it, to the latissimus dorsi, and to the
teres major and minor muscles.
   A  little below  the neck  of the scapula, it  detaches  a large
trunk, the Dorsalis Inferior Scapulae, which, winding around the
inferior costa of  the bone over the anterior margin of the sub-
scapularis and the teres minor, reaches the fossa infra-spinata.
This trunk  then divides into  two branches: one of which is dis-
tributed superficially between the aponeurosis and the infra-spi-
natus, and the other more deeply near the dorsum of the bone:
one  of the ramuscles of the  latter ascends beneath the neck of
the acromion to  anastomose with  the Dorsalis Superior Sca-
pulae.

   4.  The Anterior Circumflex Artery (Art. Circumflexa Ante^
rior, Articularis Anterior) is about the size of a crow quill, and
arises from  the axillary just above the tendon of the teres ma-
jor and of the latissimus dorsi.  It adheres closely to, and sur-
rounds the front of the neck  of the os humeri, passing between 
214
CIRCULATORY SYSTEM.
it, the coraco brachialis, and the short head  of  the biceps.   It
then divides .into several branches, some of which go to the del-
toides, and  anastomose there with  the  posterior circumflex;
others go immediately to  the articulation, and either terminate
on it or ascend to  the muscles on  the dorsum of the scapula,
where they anastomose with the scapular arteries.

   5. The Posterior Circumflex Artery (Art. Circumflexa Poste-
rior) is much larger than the last, and arises  from the axillary
somewhat below it.   It surrounds the posterior face of the neck
of the os humeri, passing  between it and the long head  of the
triceps muscle, below the  insertion of the teres  minor.  Many
of its ramifications go to the capsular ligament of the  articula-
tion and to the muscles adhering to it.  But this artery is prin-
cipally intended for the deltoid muscle, to the internal face  of
which the most of its branches go.  It  anastomoses  with the
anterior  circumflex, and with the scapular arteries.
   In some cases, the posterior circumflex arises  from the axil-
lary below, instead of above the  tendinous insertion of  the latis-
simus dorsi: when this happens, it commonly gives off the arte-
ria profunda major of the arm, and afterwards ascends on the
posterior face of the tendon to its appropriate destination,


            Of the Branches of the Brachial Artery.

   1. The Profound Artery (Arteria  Profunda  Major Humeri,
Spiralis,) arises from the brachial, a little below the tendinous in-
sertion of the latissimus dorsi, and having passed downwards, for
a short distance, it enters the interstice between the first and the
third head of the triceps muscle, and  winds spirally downwards
around the os humeri in company with the radial nerve. On the
outer side of the arm, it becomes superficial between  the mar-
gins of the triceps  and of the brachialis internus, and then  directs
its course between the latter and the supinator longus to the ex-
ternal condyle.
   In this course, the artery sends several branches to the triceps
muscle, to which, indeed, it is principally destined. Near the ex-
ternal condyle, it supplies the brachialis internus and the heads 
BRACHIAL, AND ITS BRANCHES.
215
of the extensor muscles of the fore-arm, and anastomoses with
the recurrent branch of the radial artery.

  2. The Small Profound Artery (Art. Profunda Minor) comes
from the brachial, two or three inches below the profunda ma-
jor, but frequently it is only a branch of the latter, and is gene-
rally much smaller.   It is distributed superficially on the inter-
nal face of the triceps at its lower part, and has its  terminating
branches reaching as  far as the internal condyle.

  3 The Nutritious Artery (Art. Nutritia) is the next in order
from the brachial, and arises from it near the medullary fora-
men of the os humeri, through which it penetrates, and is distri-
buted to the lining membrane of the bone.  It is not larger than
a knitting needle.

  4. The Anastomotic Artery (Arteria Anastomotica) arises from
the brachial below the last, and is larger than it.  It lies  upon
the lower internal part of the  brachialis  internus  muscle, and
crosses the ridge leading to  the internal condyle  in order to
reach the depression between the latter and the olecranon, where
it anastomoses with the ulnar recurrent artery.

   The  preceding is a common  arrangement  of the branches
proceeding  from  the brachial artery, yet deviations from  it are
continually  met with,  in a deficiency or in a redundancy of these
collateral trunks, and in their mode of origin.   An account of
all  the varieties which are observed here would be  almost end-
less, as every  subject  has some peculiarity.  Several small ar-
teries are also sent from the brachial to the  coraco-brachialis,
the biceps, the brachialis internus, and to the  triceps muscles.
They, for the  most part, are, simply, muscular branches, which
are too small and irregular to deserve specifying.
   A division of  the brachial  artery into two trunks, the Radial
and the Ulnar, will be found  in a majority of subjects in  front
of the brachialis  internus muscle on a line with the  elbow joint:
sometimes it occurs  nearer the  root of the  coronoid  process.
It is, however, by no  means rare  to see this bifurcation much
above the elbow.  Examples of it have  been witnessed at every
point between the latter and  the  arm-pit; in such cases, the 
216
CIRCULATORY SYSTEM.
 course  of the  radial artery down the fore-arm  is generally
 much more superficial than usual, as  it is  placed  immediately
 below the skin.


                    Of ihe Radial Artery.

   The  Radial Artery (Arteria Radialis)  is smaller than the
 ulnar, and extends from the elbow to the  hand.   In the upper
 half of the fore-arm it  is placed  at the bottom of the fissure
 between the supinator radii longus and the pronator teres mus-
 cle.  Having crossed the insertion of  the latter, it  runs in front
 of the radius between the tendon of the  supinator  and of the
 flexor carpi radialis.  Below the styloid process of the radius
 it runs  between  the outer end of the carpus and  the extensor
 muscles of the thumb;  it then penetrates to  the palm of the hand
 between the root of the metacarpal bone of the thumb and of
 the fore finger, above the abductor indicis muscle.
   The following branches are sent from the Radial Artery.

   1. The Recurrens Radialis arises at the neck of the radius.
 It winds, externally around the joint between the external con-
 dyle and the muscles coming from it, and anastomoses with the
 spiralis  of the humeral artery, being distributed in  many  colla-
 teral branches, to the joint and to the contiguous muscles.

   2. Several small and irregular muscular  branches arise from
 the radial artery, in its progress to the wrist: they  have no ap-
 propriate names.

   3. The Superficialis Volae arises from the radial  about the in-
 ferior margin of the pronator quadratus muscle.   It passes su-
 perficially over the process of the trapezium to the muscles  of
 the ball of the thumb, and one of its terminating branches joins
 the  arcus  sublimis. Sometimes  the  superficialis  volae is the
 principal branch of the radial.

  4.  The Dorsalis Carpi arises from  the radial at the carpus,
runs across the back of the latter below the extensor tendons,
 and detaches the posterior interosseous arteries of the back of 
SUBCLAVIAN, AND ITS BRANCHES.
217
the hand.  They anastomose with branches from the ulnar and
interosseous arteries of the fore arm.

   5.  The Magna Pollicis, a terminating branch of the radial,
comes from it in the palm of the hand  just at the  root of the
metacarpal  bone of the thumb.   It runs beneath  the  abduc-
tor indicis,  and at the  head of the metacarpal  bone  divides
into  two branches which go  respectively  along  the sides
of the thumb to its extremity, where they anastomose and ter-
minate.

   6.  The Radialis Indicis, arising at the same place with the lat-
ter, runs along the metacarpal bone of the fore finger, and along
the radial side  of the same finger to its  extremity.

   7.  The Palmaris Profunda is the third terminating branch of
the radial artery.   It arises near the  same place with the two
last,  crosses the hand between the metacarpal bones and  the
flexor tendons; thus forming the Arcus  Profundus, from which
branches proceed to the interossei  muscles; and which ends on
the ulnar side  of the palm of the hand by a connexion with
the Arcus Superficialis.

                    Of the Ulnar Artery.

   The Ulnar Artery, (Arteria Ulnaris,)  one of the forks of  the
brachial at the  elbow, passes more in a line with it than the ra-
dial artery does.  It goes, immediately after its origin, under
several of the muscles of  the internal condyle, to wit: the pro-
nator teres,  flexor radialis, flexor sublimis, and palmaris lono-us,
and between the flexor  sublimis and profundus digitorum,  be-
ing deeply seated; getting from beneath the flexor  sublimis, it
afterwards runs  parallel with the ulna, or nearly so, lying on
the flexor profundus between the  flexor ulnaris and the ulnar
margin of the flexor sublimis, and concealed  two-thirds of  the
way down the  fore  arm by the overlapping of these muscles.
At the thin part of the fore arm, commonly called the wrist, it
is  superficial, and may be felt pulsating in the living body at
the radial margin of the tendon of  the flexor ulnaris.
  The ulnar artery, at the carpus,  takes a very different course
    Vol. II.—20 
218
CIRCULATORY SYSTEM.
 from  the radial;  for it passes over the anterior annular liga-
 ment  of the carpus just at the radial side of the os pisiforme,
 to which it is held by a small ligamentous noose;  it then pro-
 ceeds to the palm of the hand.  Between the  aponeurosis pal-
 maris and  the flexor  tendons it forms that curve from the ul-
 nar to the radial  side of the hand called the  Arcus Sublimis.
 This curve commonly begins a little  beyond the anterior mar-
 gin  of the annular ligament, and presenting its convexity  for-
 wards, terminates about the middle of the ball of the thumb at
 its inner margin.
   The branches sent from the ulnar artery are as follow:

   1. The Recurrens Ulnaris arises from the ulnar about the
 lower  part of the tubercle of the radius, and, winding upwards,
 is distributed in small branches to the  muscles of  the internal
 condyle.  One of its ramuscles goes between  the internal con-
 dyle and the olecranon  process to anastomose with the arteria
 anastomotica of the humeral.

   2. The Interossea arises from the ulnar, just below the other.
 It is a large trunk, and proceeds but a little distance when it di-
 vides into two principal branches, called anterior  and posterior
 interosseal arteries.

   a. The Interossea Anterior is much the larger; it runs in con-
 tact  with the interosseous ligament to  the  upper margin of the
 pronator quadratus, giving off branches to the deep-seated mus-
 cles  of the fore arm in its  course.  Under the pronator it per-
 forates the interosseous ligament, and distributes branches to the
 back of the carpus and of the hand, which anastomose with
 branches of the radial and posterior interosseal.
   b.  The  Interossea Posterior is sometimes a separate trunk,
 arising from the ulnar just above the former.  In  either case it
 soon perforates  the interosseous ligament to get to the back of
the fore arm.   Here it  sends backwards  a  Recurrent Branch
 (Recurrens Interossea) to the back of  the  elbow, which anasto-
moses with the recurrens ulnaris and radialis.  It then proceeds
downwards, being deeply seated and distributed to the different 
SUBCLAVIAN, AND ITS BRANCHES.
219
muscles on the back of the fore arm.  Some  of its  branches
reach the wrist, and anastomose with the carpal arteries.

  3. The ulnar artery, in its descent on the fore arm, sends off
many small and  irregular muscular branches, called by Pro-
fessor Chaussier,  Cubito-muscular: they do not  require descrip-
tion.

  4. The Dorsalis Manus leaves the ulnar at the lower end of
the fore arm, and passes under the tendon of the flexor ulnaris
to the back of the hand.   It there meets ramuscles of the radial
and interosseous, and conjointly they supply with very small
branches  the  back of  the wrist, of the metacarpus, and of  the
fingers.

  5. As the Arcus Sublimis is about beginning, the ulnar arte-
ry sends superficial but small branches to the integuments of the
palm;  and a little  farther  on, a  considerable branch, which
dives into  the bottom  of the palm, through the muscles of  the
little finger, and  joins  the ulnar extremity of the arcus profun-
dus: this is the Cubitalis Manus Profunda of Haller.

  6. The Arcus  Sublimis then sends a branch to the  ulnar side
of  the  little  finger.   Afterwards  in succession three digital
branches are sent off, which, arriving at the interstices between
the  heads of their respective  metacarpal bones, each divides
into two branches to supply the  sides  of the fingers which are
opposite to each  other; one branch  is called Digito-radial,  the
other Digito-ulnar, according to the side of the  finger on which
the artery may be placed.  In this  way the radial side of  the
little finger, both sides of the ring finger, both sides of the mid-
dle finger, and the ulnar side of the fore finger are supplied.
  The digital arteries, before they divide, receive each a small
branch  from the  arcus profundus.   The digito-radial, and  the
digito-ulnar arteries, pass along the sides of the fingers in front
to their extremities: at the joints and  extremities, anastomoses
between the arteries  of the two  sides of the  same finger fre-
quently occur.
  The arcus sublimis terminates on  the radial side  of the palm
by a branch which joins the inner branch of the Arteria Magna
Pollicis of the Radial. 
220
CIRCULATORY SYSTEM.
  The most frequent distribution of the arteries of the hand is
what has just been described: anatomists are, however, not all
agreed on this point.  It would probably be more just to say,
that  this occurs more frequently than any other single arrange-
ment.  The varieties, in fact, are so great, that before a hand is
opened, it is not possible to  know in what  manner its arteries
will  be distributed.  Sometimes  the Radial Artery furnishes
one  half of the  arcus sublimis, and the  Ulnar the  other half.
On other occasions, the interosseous artery is  continued  as a
large trunk over the ligament of  the wrist, or the superficialis
volae to  join the arcus sublimis, and to complete  the digital
arteries.
   SECT. IV.--BRANCHES OF THE DESCENDING THORACIC AORTA.

  The Aorta, in its course from the lower part of its curvature
to the crura of the Diaphragm, gives off several branches to the
viscera and to the parietes of the thorax.

  The  Bronchial  Arteries (Arterice Bronchioles)  are  the  nu-
tritious vessels of the lungs.   There is commonly one for each
lung, but sometimes two or more.   The right arises frequently
from the superior aortic intercostal artery, instead of from the
aorta, while the left comes from the latter: occasionally  they
have a common root.
  On either side they follow the course of the bronchus  into the
substance of the lung; and are distributed along with it, by ra-
mifications which become  successively finer  and finer, and
anastomose with the pulmonary artery; after the manner men-
tioned in the description of the lungs.  Before  they enter the
latter, they send some small ramifications to the posterior me-
diastinum, to the pericardium, and to the black bronchial glands.

  The Oesophageal Arteries (Arterice Oesophageal) are general-
ly five or six small twigs which  come successively from  the
descending thoracic aorta.  They ramify minutely in  the sub-
stance of the oesophagus, communicating freely with each other:
the lowest of them also anastomoses around the cardia with the
superior coronary artery of the stomach. 
SUBCLAVIAN, AND ITS BRANCHES.
221
    The Posterior Arteries  of the Mediastinum, (Arterice  Me-
  diastinals Posteriores,) are numerous and  small;  they come
  from the  anterior face of the aorta, as well as from the branches
  last mentioned; and are spent upon the posterior mediastinum,
  and upon its contents.

    The Intercostal Arteries  (Arterice Intercostales lnferiores  Aor-
  ticce) of the aorta  supply the ten lower  intercostal spaces on
  each side, as the two upper ones are supplied by the subclavian
  artery.   There is commonly an intercostal  artery arising dis-
  tinctly from the aorta for  each space, but  sometimes two  of
  them arise from a  common trunk.  Those for the right  side
  having to cross the spine behind the oesophagus and  the vena
  azygos, are, of course, longer than such as belong to the left.
-  The upper ones on either side have  to ascend, in order to reach
  their destination.
    Each artery joins the rib near its tubercle, and goes along
  the groove in  its lower margin, between  the external and the
  internal intercostal muscle, for two-thirds of the  length of the
  rib.  It then abandons the groove, and divides into several
  branches, which go to the  intercostal muscles and contiguous
  parts, and anastomose in front with the internal mammary ar-
  tery.
    As each intercostal artery passes the head of the rib, it sends
  a branch backwards, (ramus dorsalis,) between the transverse
  processes of the adjoining  vertebrae, which penetrates  to the
  posterior face of the trunk, and is distributed  to the muscles and
  skin on the side of the spine.  A ramification from this branch
  enters the intervertebral foramen, and is  spent upon  the  me-
  dulla spinalis and its membranes.
    Each intercostal  artery  also  gives  off, about the middle of
  the  rib, a  branch, (ramus costalis inferior,) much smaller than
  the  trunk.  This branch advances  along the upper margin of
  the  rib below, and gives ramifications to  its  periosteum and to
  the  adjacent intercostal muscles.
    The last intercostal artery is remarkable for its size.  Its
  origin is concealed by the small muscle  of  the diaphragm, to
  which it gives some ramifications: it then passes, at the under
  margin of the rib, behind the upper end of the quadratus lum-
  borum  muscle, where  it divides into  three  branches; one of
                             20* 
222                 CIRCULATORY SYSTEM.

which goes transversely to the broad muscles of the abdomen;
while the  other two  descend between  the oblique and trans-
verse muscles towards the crest of the  ilium, where they anas-
tomose with the lumbar arteries, and with the circumflexa ilii.
     SECT. V.--OF THE BRANCHES OF THE ABDOMINAL AORTA.

   The Phrenic Arteries (Arterice Phreniccc) are two in num-
 ber, one for the right and the other for the left side of the dia-
 phragm.  They arise singly, but sometimes'by a common trunk,
 from the front of the aorta, immediately on the latter showing
 itself in the abdomen, between  the  crura of the  diaphragm;
 consequently, just below the crossing  of  the muscular  fibres,
 which takes place between the foramen for the aorta and  that
 for the oesophagus.
   The phrenic  arteries  ascend along the  lesser  muscle of the
 diaphragm, and give some ramifications to  it and to the capsulae
 renales.   They then divide each into  two leading trunks, which
 are distributed over the  diaphragm, principally on  its concave
 surface.   Some small ramifications from  them go to the liver
 and to the lower part of the oesophagus.
   The two phrenic arteries anastomose with each other: also,
 with the superior phrenics,coming from the internal mammary;
 and with the intercostals.  Sometimes one or both of them come
 from the cceliac artery, or its branches.

   The Cceliac Artery (Arteria  Cceliaca) is  the next branch of
 the abdominal aorta, and arises immediately below the phrenics,
 between the pillars of the  diaphragm, opposite the junction of
 the last dorsal with the first lumbar vertebra.   It is a very large
 trunk, and goes off at right angles, being  placed between the
 left lobe of the liver and the superior margin  of  the  pancreas.
 When it is only half an  inch long, it  is  split into three trunks,
 the Gastric, the Hepatic  and the Splenic;  this division  is the
Tripus Halleri.

   The  Gastric  Artery (rfrleria  Gastrica, Coronaria Ventri-
 culi) is the smallest of the three trunks, and frequently arises
from one of the  others.   It advances forwards and towards the 
BRANCHES OF THE ABDOMINAL AORTA.
223
left, in order to reach the  small curvature of the stomach, the
course of which it pursues to the pylorus, between the two lami-
nae of the little omentum.  It gives off the following branches:—
   a.  Ramifications to  the oesophagus, some  of which  ascend
along it into the posterior mediastinum, and  anastomose there
with the similar  branches coming  from the aorta; others go
transversely, so as  to  surround the cardia,  reach  the greater
end of the stomach, and anastomose with the vasa brevia.
   b. The ramifications to the stomach are abundant, but of an
indeterminate number, and  arising  along its lesser curvature,
are distributed  in winding branches to the anterior and the pos-
terior surfaces  of this viscus, between its membranes.
   c.  Not unfrequenlly the artery which supplies the left lobe of
the liver is  a branch from the gastric, in which case  the latter
is much larger than usual.

   2.  The Hepatic Artery (Jlrteria Hepatica) is generally con-
siderably larger than the gastric, and inclines towards the right
side,  in order to reach the liver, which it does through the cap-
sule of Glisson.   It sends off the following branches:—
   a.  The  Right Gastric or Gastro-Epiploic  Artery  (Jlrteria
Gastrica Dextra) comes  from it near the pylorus, and descend-
ing between the  duodenum and pancreas, reaches  the greater
curvature of the stomach, to the right half of which, and to the
corresponding  part of the great omentum, it  is distributed.   In
the early part  of its course, the right  gastric  detaches some
small ramifications to the pylorus  (arlerise pyloricse;)*'also, to
the duodenum  and to the pancreas (art. pancreatico  duode-
nales.)  The latter communicate,  by  very free anastomoses,
with  the superior mesenteric artery.
   After having sent off this branch, the hepatic artery advances
to the transverse fissure of the liver, in front of and to the left
of the vena portarum.  It then divides into a right and a left
branch.  The former sends off a  ramification to the  gall-blad-
der, (art. Cystica,) which first  reaches its neck, and is distri-
buted, by many arterioles, upon the parietes  of this reservoir;
the right branch  then penetrates deeply into  the  transverse fis-
sure,  and is  distributed  by many ramifications, throughout the
rifht  lobe of the liver.   The left branch of  the hepatic artery 
224
CIRCULATORY SYSTEM.
is distributed, in the same  manner, throughout the left  lobe of
the liver.

  3. The Splenic  Artery  (Arteria Splenica) is larger in the
adult than either of the other two branches of the  cceliac, and
goes to the spleen along the  superior  margin of the pancreas,
performing, in this course, several considerable flexuosities.   It
gives off the following branches:—
  a. The Pancreatic Arteries, (Art. Pancreaticce Medics et Si-
nistral) come successively from  its inferior margin, as  it goes
along the pancreas.   Their number and size are variable, but
commonly they are not bigger than a knitting needle: they pe-
netrate perpendicularly into the pancreas, and then subdivide
minutely in furnishing its structure.
  b. The Left Gastric Artery (Art.  Gastrica Sinistra,  Gastro-
epiphica Sinistra) comes from the left extremity of the  splenic,
and is  about the same  size with  the right gastric artery, but
sometimes larger.   It attaches itself to the left extremity of the
stomach, and goes along the left half of its greater curvature,
terminating by an  anastomosis with the right gastric  artery.
In this course, it detaches ramifications to the front  and  to the
back of the stomach,  and to the omentum majus.
  c. The Short  Vessels (Vasa Brevia, Art. Gastrica?  Breves)
come from the splenic, immediately before it enters the spleen,
and after it has subdivided  for that purpose.   They are five or
six in number, and are distributed upon the  greater extremity
of the  stomach, between the cardia and the left gastric artery.
The anastomoses between  the several  arteries of the stomach
are so  free, that a  fine injection pushed  into one, readily finds
its way into all the others.
  The splenic artery, when it gets to  the  left end  of the pan-
creas, is divided into a cluster of branches, and in that condition
enters  the fissure of the spleen, throughout the interior of which
it is divided into an infinitude of ramifications.

  The Superior  Mesenteric Artery (Arteria  Mesenterica Supe-
rior) arises from the aorta, while  the latter is still engaged, be-
tween  the crura of the  diaphragm.  It is  about the same size
as the  cceliac, and comes off half  an inch below it.  It is dis- 
branches of the abdominal aorta.           225
tributed to  all the small intestines and to the right side of the
large one after the following manner: it first passes behind the
pancreas, and then in front of the duodenum, to reach the root
of the  mesentery, between the two laminae of which it divides
and subdivides into several series of arches,  one after another:
they become successively smaller and more  numerous till they
reach the margin of the intestine, where they cease by sending
a great many small parallel branches.
  The trunk of  the superior mesenteric artery, in descending
between the laminae  of the mesentery, describes a  considera-
ble curvature, the convexity of which is to the left side and
downwards, while its concavity is in a contrary direction.   It
is from the convexity of this trunk, that from fifteen to twenty
large branches are sent off successively to form the roots of the
first row of arterial arches.  These  branches are shorter, and
generally somewhat  smaller, the  lower down  they  arise; and
their origins very closely  succeed each other.   Upon the first
row of arches or anastomoses is formed a second more nume-
rous and  small, and  upon the second row  is formed a third
still more numerous  and  small, from which  proceed the  intes-
tinal branches.
   Besides  the preceding branches, the superior mesenteric ar-
tery sends off the following:
   Near its root  several small  ramifications arise, which  go  to
the duodenum and to the pancreas, and anastomose there with
the other arteries supplying the same organs.     *
   From about the middle of the concavity of the superior me-
senteric artery,  arise the three Colic arteries called  lleo-colica,
Colica Dextra, and Colica Media: the first supplies a cluster of
branches to the  lower part of the ileum and to the head of the
colon,  anastomosing  on the left with the last of the small intes-
tinal arteries and on the right with the. colica dextra: the Co-
lica Dextra is smaller than either of the  other  two branches,
and going  between  the laminae of the mesocolon, supplies the
ascending  portion of the  colon  by dividing into two principal
branches,  one  of which  anastomoses with the  ileo-colic ar-
tery,  and  the other with  the colica media: the Colica Media,
situated between the laminae of the transverse mesocolon, and
arising higher up than the colica dextra, advances forwards and 
226
CIRCULATORY SYSTEM-
divides  into two principal trunks; one of which  supplies that
part of  the  colon  in the right hypochondriac  region, and the
other the remainder of its transverse portion, forming  an anas-
tomosis with the colica superior of the inferior mesenteric ar-
tery.   The  arteries which supply the  colon differ from  those
supplying the  small  intestines,  in  forming but  one row  of
arches;  which, in fact, are  produced  by the  anastomoses
spoken of, and have, therefore, extremely large  meshes.  From
the convexity of these arches,  many parallel branches run out
to supply the colon, and are very minutely distributed to it.

   The  Capsular Arteries, the Emulgents, and  the Spermatics,
arise  from the aorta, between the superior and  the inferior me-
senteric.  But they will be described after the inferior mesen-
teric, so as to  keep together  the account of the arteries of the
intestines.

   The Inferior Mesenteric Artery, (Art.  Mesenterica Inferior)
generally arises about one inch  above the division of the  aorta
into the two primitive iliacs, and  is much smaller than the su-
perior Mesenteric.  It inclines downwards to the left side, and
gets between the laminas of the mesocolon ;  it then divides into
three branches, called the Left  Colic Arteries, from their distri-
bution to the left side of the colon.   From their relative  situa-
tion to each other, they are distinguished  into the  Superior, the
Middle, and the Inferior; sometimes, however, there are but
two of these trunks.

   The Superior Colic (Art. Colica Sinistra Superior)  goes hori-
zontally towards the colon in  the left lumbar region; having got
near the intestine it divides  into  two branches, one  of  which
ascends to the  transverse colon to form the anastomosis with
the Colica Media of the  upper mesenteric, while  the other de-
scends to unite with the colica  media sinistra.  The middle Co-
lic Artery (Art. Colica Sinistra Media) is sometimes a branch of
the superior, and is occasionally wanting; it goes towards the
upper part of  the sigmoid flexure of the colon, and  then  bifur-
cates: one branch  ascends to form by anastomosis  an arch with
the superior colic, while the other branch descends to join the
lower colic artery.  The Inferior Colic Artery (Art.  Colica Si- 
BRANCHES of the abdominal aorta.
227
 nistra Inferior) goes towards the middle of the sigmoid flex-
 ure of the colon, and there, like the preceding, divides into two
 branches; one anastomoses with the artery above, while the
 other joins with the  arteries which go to the rectum from the
 inferior mesenteric.
   The  Superior  Haemorrhoidal Artery  (Art. Haemorrhoidea
 Superior, Lnterna,)  is the  lowest and the  last  branch of the
 inferior mesenteric.   It  descends between  the laminae of the
 mesorectum, and is divided into two symmetrical trunks, which
 radiate by dividing  and subdividing on  the  side of the rec-
 tum,  and are dispersed  in  very fine and numerous branches
 throughout its substance;  and anastomose with  the middle
 and the  inferior haemorrhoidal  arteries, also  with  the lateral
 sacral.

   The Capsular Arteries (Art. Cupsulares) arise frequently from
 the aorta just below  the superior mesenteric; but quite as  often,
 if not more so, from the  emulgents.  They are not larger than
 a crow's  quill, and vary  from one to three on either side, gene-
 rally, however, not exceeding one: when  they do, they are pro-
 portionably small.   Passing horizontally  outwards, they divide
 into several small ramifications, which terminate in the capsulae
 renales.   Some of their branches go to the lesser muscle of the
 diaphragm.

  The Emulgent Arteries (Art. Emulgentes, Renales,) are two
 in number, one for each kidney, but sometimes  more.   They
 are large  and short, arise from the side of the aorta immediate-
ly below the superior mesenteric, and pass outwardly in a hori-
zontal direction.   The  right one is  longer than the left, some-
what lower down, and passes behind the ascending cava.  They
are both, in their course,  from the aorta to the kidney, covered  .
in front by the emulgent vein, and have to pass through a mass
of adipose matter.
  The emulgent sends off some fine ramifications to the  adipose
matter, which surrounds it, and before it  reaches  the fissure of
the kidney divides  into three or four branches, preparatory to
its introduction into this gland, upon the structure of which it is
ultimately distributed by very fine branches. 
228
CIRCULATORY SYSTEM.
   The  Spermatic Arteries (Arteriae Spermaticae, Seminales,)
arise from the aorta  somewhat below the  emulgents, but in
some cases from the latter themselves.  They are two in num-
ber, one on each side, and are about the size of a crow quill in
the male subject, but smaller in the female.   One comes off ge-
nerally higher up than  the other; they then descend on the sides
of the vertebral column before the psoae muscles, and cross in
front of the ureters, being  in all this  course behind the perito-
neum.  They are tortuous, and shortly after  their origin begin
to adhere to the spermatic veins, which adhesion is continued to
the testicle.
   The branches that the spermatic artery sends off in the abdo-
men are inconsiderable, consisting in very fine  twigs to the ad-
jacent adipose  matter, to  the lymphatic glands, to the ureter,
and to the peritoneum.  In the male  subject it passes with the
vas deferens, through  the  abdominal canal,  and  reaching the
testicle divides into branches which supply the  body of this gland
and the epididymis.   In descending from  the external ring to
the testis, some small ramifications, to the  adjacent parts, leave
it.  In the female, the spermatic artery does  not leave the ca-
vity of the abdomen,  but, descending into the  pelvis, gets be-
tween the laminae  of the broad ligament to the  ovarium, and is
spent principally upon  the latter.   Some of its  branches go to
the Fallopian Tube, to the Round Ligament of the uterus, and
to the sides of  the latter, where they anastomose with the ute-
rine arteries.*
  The Lumbar Arteries (Arteriae Lumbares) are commonly five
in number on either side, but seldom less than three, and in their
course outwards, correspond with the intercostal arteries. They
are much larger than the latter.   They arise  in pairs from  the
posterior external face of  the aorta, at a point corresponding
with the middle of the bodies of the four upper lumbar verte-
bras, and pass outwards between  the fasciculi  of the psoas mag-
nus muscle, to which, to the quadratus lumborum, and the bodies
of the vertebras, they distribute several branches.  Sometimes
each pair arises by a common trunk from the posterior face  of

  * The spermatic artery    pindle-shaped, the smallest  end being the origin;
this favours die flow of blood in it, which would otherwise suffer from so much
friction. 
ERANCHES OF THE ABDOMINAL AORTA.
229
 the aorta.  As the latter terminates at the fourth lumbar verte-
 bra, the fifth lumbar artery is a branch from the fourth in most
 instances.
    At the base of the transverse process each artery divides into
 two branches, a posterior or dorsal one, and an  anterior or
 lumbar.  The dorsal branch, which  is smaller than the other,
 detaches a ramification through the intervertebral foramen to
 the lower part of the medulla spinalis and to the cauda equina:
 it  then gets to the back, where it is spent upon the muscles near
 the spine.  The  anterior lumbar branch advances between the
 broad muscles of the abdomen, to which it is distributed;  and
 runs  forwards far  enough to  anastomose with the epigastric
 artery.
    The first lumbar  artery is small, and sometimes comes from
 the last.intercostal; it goes a little below the inferior margin of
 the last rib, and then descends almost vertically between thfi pe-
 ritoneum and  the transversus  abdominis muscle.   The lower
 lumbar arteries anastomose with ihe circumflexa ilii, and  with
 the superficial  branches of the gluteal.

   The Middle Sacral Artery (Arteria Sacra Media) is generally
 not so large as a lumbar; it arises from the centre  of the bifur-
 cation of the aorta into the two primitive iliacs, or else a line or
 two above it, behind.  It descends, in front of the middle line of
 the fifth lumbar vertebra and of  the sacrum, to the coccyx,
 adhering to the surface of these bones, and  performing some
 flexuosities.
  It sometimes happens that  the  last pair of lumbar arteries
 come from it, or at least one, according to Meckel, more com-
 monly the left:  in which case the sacral is of unusual size.  The
 sacral  afterwards sends off, to  the  right and  left, a pair of
branches for each pair of sacral foramina.  They run across the
sacrum, send branches to it, anastomose with  the lateral sacral
arteries, and then penetrate to the cauda equina.  The middle
sacral  artery is  lost at the inferior end of the coccyx, in the fat
and cellular tissue of the part.
Vol. II—21 
230
CIRCULATORY SYSTEM.
SECT. VI.--OF THE PRIMITIVE ILIAC ARTERIES, AND THEIR BRANCHES.

  The Primitive Iliac  Arteries,  (Art. lliaca Primitive, com-
munes,) one on each  side, are, as mentioned, the  terminating
trunks of the abdominal aorta.  They extend from the lower
part of the fourth lumbar vertebra to the sacro-iliac junction, or
near it, where they divide into two trunks, the Internal and the
External Iliac.
  The primitive iliac is  bounded on the outer side by the psoas
magnus muscle, and behind  by the primitive iliac vein; it is
crossed at its lower part by the ureter.  No branches deserving
of especial notice are sent from it before  it bifurcates; such as
exist  are very small, and go simply to the parts immediately
contiguous.  The right  artery crosses in front of the root of the
left iliac vein.


  SECT. VII.--OF THE INTERNAL ILIAC, OR HYPOGASTRIC ARTERY.

  The Internal Iliac Artery (Art.  lliaca Interna, Hypogastricd)
descends from the front upper part of the sacro-iliac junction,
to the  lower part of the same articulation.   In  this descent, it
is bounded behind by the sacral plexus of nerves, and gives off
several arterial trunks;  but the manner by which the last is  ac-
complished is much varied in different subjects.  For the most
part, it is an inch or more long before any important branches
leave it;  it is then frequently divided into two principal trunks,
an anterior and a posterior, from which proceed  the  several
branches that supply the internal  and  the external  parts of  the
pelvis.  The rule of origin  of the secondary trunks from these
two principal ones, even when the latter exist, is not fixed; for
sometimes they arise from  one, sometimes from the other, and
then again/rom the trunk of the hypogastric itself.

  The Ilio-Lumbar Artery (Art. Ilio Lumbaris) is commonly the
first branch of the hypogastric, or of its posterior trunk.  It as-
cends outwards and backwards behind the psoas magnus mus-
cle, and  there divides into  two branches, a superior and an in-
ferior. The former  continues  to ascend  between the psoas
masnus and the  iliacus internus muscle, to  which, and to the 
          INTERNAL ILIAC ARTERY, AND ITS BRANCHES.        231

quadratus lumborum, it distributes branches: it also sends rami-
fications into the spinal cavity, and anastomoses with the lower
lumbar  arteries; sometimes it supplies the place of the last lum-
bar entirely.  The inferior branch, going outwardly, is divided
into  two orders of ramifications which supply the iliacus inter-
nus muscle, on its surface and more deeply; also the os ilium by
a ramuscle which penetrates the nutritious foramen of the latter.
The inferior branch anastomoses with the cireumflexa iliiof the
external iliac.

   The Lateral Sacral Arteries (Arterice Sacrcs Laterales) arise
next, either from the hypogastric or from its posterior trunk:
their number is commonly equal to that of the foramina on the
side of the sacrum in front, though they come from only one or
two roots.  They eross the front of the sacrum, and divide into
branches, some  of which anastomose with the middle  sacral
artery, while  others enter the foramina of the sacrum, to be
spent on the lower part of the cauda equina.

   The  Obturator Artery (Arteria  Obturaloria) comes  common-
ly from the hypogastric or from one of its principal trunks; in
some eases it arises from the epigastric  or  from the external
iliac, near Poupart's ligament.   In the first cases  it passes for-
wards  parallel with the brim  of the pelvis, and  in the latter
cases  it  descends  behind the superior  ramus of the pubes.
Whatever may be the condition of its origin, it gets from the
pelvis through the upper part of the thyroid  foramen over  the
superior margin of the obturator internus muscle, having  pre-
viously sent off some inconsiderable ramifications to the peri-
osteum and the  contiguous muscles.
   It emerges  from  the pelvis on the upper margin  of the obtu-
rator externus muscle, and  then divides into two principal
trunks.   The posterior descends  along the external  margin of
the  obturator externus muscle, to which  it gives ramifications;
it likewise sends some branches to the heads of the  muscles
 coming from  the tuber of the ischium, and thereby anastomoses
 with the sciatic artery; other branches are  spent upon the hip
joint, one of  which gets into the  cavity of  the  latter  through
the  notch at the lower part of the acetabulum, and  is spent
upon the adipose matter in its bottom.  The anterior branch 
232
CIRCULATORY SYSTEM.
goes to the heads of the adductor muscles, to the pectineus, to
the obturator externus, and to the integuments of the upper in-
ternal partof the thigh.  Near its origin  this branch sends  a
ramification along the internal margin  of  the thyroid foramen
to anastomose with the posterior branch, so that the foramen
is surrounded by an arterial circle.

  The Middle Haemorrhoidal Artery (Art. Hamorrhoidea Media)
varies in its origin, being sometimes from the  hypogastric it-
self, and, on other occasions, from one  of  its branches, as the
gluteal, ischialic, &c.  It descends on the  fore part of the rec-
tum, opposite the lower fundus of the bladder in the male, and
is distributed by branches to the rectum, to the vesiculae semi-
nales, and to the prostate gland.  In the  female it  dispenses
branches to the vagina.  It is called middle, from its position
between the upper and the  lower haemorrhoidal arteries.
  In both sexes, the branches which it sends to other parts be-
sides the rectum, frequently arise from  other arteries, and in a
manner which  causes  them to have distinct appellations, as
vagina], &c.

  The Vesical Arteries (Arterise Vesicates) consist  in  several
ramifications, coming from what was  the umbilical artery of
the foetus, but which, in the adult, with  the exception of a  short
space near its origin, is converted into a  ligamentous chord.
These branches ramify upon the parietes of the bladder; one
of  them, more voluminous than any other, and  called, by M.
Chaussier, vesico-prostatic, gains the lower fundus of the  blad-
der; sends branches to it, to the prostate, to the vesiculae semi-
nales, and to the commencement of the urethra.

  The Uterine Artery (Arteria  Uterina)  arises from  the hy-
pogastric, or one of its branches, near  the vesical,  sometimes
before, and on other occasions subsequent  to them.   Being pe-
culiar  to the female sex, its size varies  according to the  indi-
vidual, being in a  state of pregnancy or not: in the latter stages
of gestation it  is  as large  as  any other branch of  the hypo-
gastric.
  It goes inwards  towards the  superior part of the vagina, to
which it gives some ramifications; it then ascends between the 
            INTERNAL ILIAC ARTERY, AND ITS BRANCHES.        233

 laminas of the broad ligament, in a tortuous manner along the
 side of the uterus, and  divides into many branches which are
 distributed through the  tissue of this organ.  It anastomoses
 with the corresponding arteries of the other side, and with the
 branches of the spermatic artery which go to the Fallopian tube
 and to the ovarium.

   Besides the preceding, the hypogastric, or Internal Iliac ar-
 tery sends off two large branches, the Gluteal and the Ischiatic.
 which terminate it.  In many subjects they are the direct con-
 tinuation of the two primitive trunks, into which the hypogas-
 tric ii frequently originally divided.

   The Gluteal Artery, (Arteria Glutea,) shortly after its origin,
 issues from the pelvis above  the pyriformis  muscle, at the up-
 per part of the ischiatic foramen, where it  adheres closely to
 the edge of the bone.   When it first gets to the dorsum of the
 ilium, it is covered  by the  gluteus magnus muscle, and lies at
 the posterior margin of the gluteus minimus, precisely under a
 line drawn from the  posterior superior spinous process to the
 top of the trochanter major.   It almost immediately afterwards
 divides into two principal trunks.
   One of these trunks, the more superficial, advances between
 the gluteus medius and the  magnus, and distributes branches to
 them; also, to the posterior margin  of the  magnus, where it
 comes from  the  posterior sacro-sciatic ligament.  The  more
 deeply-seated trunk goes forwards between the gluteus medius
 and minimus, and subdivides into three orders of branches for
 their supply.  One set follows the superior margin of the glu-
 teus minimus towards the  anterior superior  spinous process;
 another set passes nearer the  middle of the  gluteus minimus;
 and the third set still lower down upon the dorsum of the ilium,
 above the acetabulum; some of the ramifications go to the cap-
 sular ligament  of  the joint,  where they  anastomose  with
 branches from the femoral  artery.

   The Ischiatic Artery [Arteria Ischiadica) is somewhat smaller
than the gluteal, but looks rather more like the continuation of
the hypogastric.  It descends between the rectum and the py-
riformis muscle, and issues under the lower margin of the lat-
ter, out of the pelvis, being there placed in front of the sciatic
                           21* 
234
CIRCULATORY SYSTEM.
nerve.  It goes downwards on the back of the thigh, between
the trochanter major and  the tuberosity of the ischium, being
at the internal edge of the sciatic  nerve, and on  the posterior
face of the small rotator muscles of  the thigh.  It sends off in
the pelvis the internal Pudic Artery, and also some inconstant
branches, of small size, to  the viscera within the  pelvis; when
it has emerged from the latter, it  detaches some considerable
branches to the origin and to the inferior margin of the  glu-
teus magnus muscle, and to  the small rotator  muscles.   The
branch which may be considered as  the continued trunk of the
ischiatic, descending on the posterior face of the thigh, along
with the sciatic nerve, under the  hamstring muscles, is lost in
ramifications to them, and by anastomoses with the perforating
arteries.

  The Internal Pudic Artery, (Arteria Pudica Interna,) though
a branch of the ischiatic, is only in a slight degree smaller.  It
arises a little above the spinous process  of the  ischium, in the
pelvis, in front of the sciatic plexus, and  gstting from the pelvis
between  the anterior sacro-sciatic ligament  and the inferior
margin of the pyriformis muscle, it  passes over the posterior
face of the anterior sacro-sciatic ligament, at the spinous  pro-
cess of the  ischium.  It immediately afterwards returns  into
the cavity  of the  pelvis, between  the two sacro-sciatic liga-
ments, at the place where the obturator  internus muscle winds
over the  ischium;  it then  goes along the internal face of the
latter bone and of its ascending ramus,  at the inferior margin
of the obturator internus muscle; and continues on the internal
face of the ramus of the pubes, between the two laminas of the
triangular ligament, above the crus of the penis  to the symphy-
sis of the pubes.
  In this course ihe Internal Pudic Artery detaches several im-
portant branches, in the following order:—
  a. A ramification along the inferior margin of the pyriformis,
to this muscle and  to the parts on the posterior face of the  neck
of the os femorfs, where it  anastomoses  with  the other arteries
of this region.
  b. The Lower Haemorrhoidal Artery (Art.  Ha-.morrhcidea In*
ferior Externa)  to  the  inferior part of the  rectum, and  to the
external sphincter ani muscle.   This artery arises after the inter- 
           EXTERNAL ILIAC ARTERY, AND ITS ERANCHES.        235

nal pudic has returned within the pelvis, and consists sometimes
in several branches.
   c. The Perineal Artery (Art.  Perinea, Transversa  Perinei)
has its root  near the origin of the transversus perinei muscle,
and advancing obliquely forwards  is distributed in several ra-
mifications  to the muscles and integuments of the perineum,
and to the posterior part of the scrotum.  It is unavoidably cut
in the lateral  operation for the stone.   In the female it goes to
the sphincter vaginae and to the labium externum.
   d.  When the  internal pudic has  got  beyond the transversus
perinei muscle near the beginning of the crus  penis,  it detaches
to the bulb  of the urethra, along the posterior margin of the tri-
angular ligament, a branch which penetrates to the corpus spon-
giosum, and is minutely distributed upon it, some  of its ramifi-
cations reaching to the corpus cavernosum.  This branch is
called  by M. Chaussier, Urethro-bulbar, and  instead of being
always distinct, it on some occasions comes from  the Perineal.
   e.  At the under part  of the symphysis pubis, between  it and
the back of the  penis, the internal pudic sends forwards,  on the
dorsum of the penis, a  superficial branch, (Ramus Superficialis
Dorsi Penis.)  It advances to  the end of the penis, under the
skin, being parallel with its fellow of the other side, and near to
it: sometimes the two unite after a short course.  They are dis-
persed  in branches to the integuments, and  to the elastic liga-
ment of the penis.
   /.  The Cavernous Artery of the Penis (Art. Cavernosa Pro-
funda  IJenis) may  be  considered  as the terminating  trunk  of
the interna! pudic.  It  penetrates  the corpus  cavernosum, be-
neath the symphysis of the pubes, and quickly  divides into many
ramifications.  The latter advance, and continue to subdivide
upon the cells  of the  corpus  cavernosum, to which  they are
principally distributed: some of them reach the corpus spongio-
sum urethras, and others anastomose with the corresponding ar-
teries of the other side.

    SECT. VIII.--OF  THE EXTERNAL ILIAC ARTERY, AND ITS
                         BRANCHES.

   The  External  Iliac Artery (Arteria lliaca  Externa) extends
from the bifurcation of the primitive iliac to Poupart's ligament, 
236                 CIRCULATORY SYSTEM.
 where it is continued to the lower extremity under the name of
 the femoral artery.  It looks like the continuation of the primi-
 tive iliac, and descends at the superior strait of the pelvis along
 the internal margin of the  psoas magnus muscle.  In the early
 part of its course, it is anterior to the external iliac vein; it then,
 as it approaches Poupart's ligament, gets to its outer margin.
 It is covered by the peritoneum in front.  Where it  passes  be-
 neath Poupart's ligament to the thigh, it is  about half way  be-
 tween the anterior superior spinous process of the ilium and  the
 symphysis pubis, having the vein  at  its  pubic margin and  the
 anterior crural nerve, half  an inch from its iliac margin.   No
 branches  of consequence arise before it reaches the crural arch;
 it then sends off  two, the Epigastric and the Circumflex Iliac
 Artery.

   The Epigastric Artery (Arteria Epigastrica) arises  somewhat
 above the crural  arch, at the  line where the peritoneum is  re-
 flected from the fascia transversalis upon the iliac fascia.  It at
 first passes  horizontally inwards, then rises obliquely upwards
 and  inwards, behind the spermatic chord, at the pubic margin
 of the internal abdominal ring.  Afterwards it reaches the ex-
 ternal margin  of the rectus abdominis  muscle, two or three
 inches above the pubes: ascending along it for a  short distance,
 it then passes  to its  posterior face,  and continues  ascending
 above the umbilicus; where being divided into several branch-
 es, it terminates by anastomosing with the lower ramifications
 of the internal mammary artery.
  This artery is almost entirely spent  upon the anterior parietes
 of the abdomen,  in ramifications,  which anastomose with  the
 last intercostal  and with the lumbar arteries. One of its small
 twigs, called  the External Spermatic  artery,  following  the
 course of the spermatic chord, or of the  round ligament, is
 distributed upon the cremaster, the  tunica  vaginalis,  and  the
 scrotum of the male, and upon  the mons veneris  of the female.
 In some cases the epigastric gives off the obturator artery as
 stated.

  The Circumflex Iliac Artery (Arteria Circumfiexa llii) is of the
same size with the epigastric, and comes from the external iliac,
sometimes on a level with it, and on other occasions lower down, 
FEMORAL ARTERY, AND ITS BRANCHES.
237
even below the crural arch.  It ascends outwardly towards the
anterior superior spinous process of the ilium, along the posterior
margin of the crural arch, and following afterwards the direc-
tion of the crista of the ilium,  it anastomoses with the  corre-
sponding branch of the ilio-lumbar artery.
  The following branches come from it.  In the early part of
its course some unimportant twigs are sent to the adjacent mus-
cles, as the sartorius,  iliacus internus, and so  on.  At the ante-
rior superior spinous process, it divides  into two branches; the
smaller ascends between the internal oblique and the transversa-
lis  muscle, and is distributed  upon  them;  the other branch,
which is the continuation of  the main trunk along the  crista of
the ilium at the margin of the iliacus  internus muscle, sends ra-
mifications  to  the latter, and also to the posterior part of the
broad muscles of the abdomen, where it anastomoses  with the
other arteries of this region.


                  Of the Femoral Artery.

  The Femoral Artery (Arteria Femoralis, Cruralis,) the conti-
nuation of the external iliac, extends from the crural arch to the
perforation for its  passage through the adductor magnus, which
is commonly one-third of the whole length  of the os  femoris,
above the knee joint.  This  great  trunk, immediately below
Poupart's ligament is very superficial, and may be felt pulsating
where it passes over the pubes.  It is there covered only by the
common integuments, and the fascia femoris, which  is  thin;  it
is bounded  internally by the femoral vein, externally by the
crural nerve, is half-way between the anterior superior spinous
process and the symphysis of the pubes, and Jies  upon the inter-
nal face of the psoas magnus over the interstice between it and
the pectineus.  In the upper third of  its course the femoral ar-
tery is at the inner edge of the rectus femoris, and at  a  short
distance from it; it then inclines inwards, and occupies the angle
formed by the adhesion of the vastus internus to the  adductor
longus.  The sartorius, at first, is remote at its outside, but this
muscle inclining inwards  in its descent gets to the exterior mar-
gin of the artery, and afterwards covers it completely for the re- 
238
CIRCULATORY SYSTEM.
mainder of its course.   The femoral artery is in  front of the
femoral vein when it has descended three or four inches below
the crural arch; behind the two is the arteria profunda. When
the femoral artery and vein reach the angle formed by the vas-
tus internus and  the adductor longus, they are covered by  a
strong  interlacement of tendinous fibres from these muscles.
  The femora] artery sends off these branches:

   1.  The Superficial Artery of the Abdomen (Art. ad Cutem
Abdominis) is small, and arises at the lower margin of Poupart's
ligament; it goes  upwards  towards the  umbilicus, lies beneath
the fascia superficialis abdominis, and is  distributed to  the inte-
guments of this region.  One of its ramifications goes to the in-
guinal glands.

  2.  The External Pudic Arteries (Art. Pudendce Externce) come
from the  femoral at the same point, and are two or even three
in number; they are of small size.  One of them inclines inwards
along the groin, between the skin and the fascia femoris, and is
distributed to the integuments of the pubes, to those of the pe-
nis, and to the scrotum, or to the labium externum of the female.
The second, and the third, when it exists,  are rather lower down,
and are dispersed upon very much the same  parts.  The lym-
phatic  glands of the groin also derive their supply of blood from
these external pudic arteries.

  3.  The Profound  Artery, (Arteria Profunda Femoris,) the
great muscular artery of the thigh,  is but slightly inferior in
size to the femoral itself, and comes from the  latter at the dis-
tance of from one to two inches below the crural arch.   It lies
behind tj^e femoral artery, and descends in  that  situation be-
tween the insertion of the adductor brevis and the vastus in-
ternus muscle, to  the upper  part of the insertion of the ad-
ductor longus.  In this course its size is much diminished by
the origin from it  of several considerable trunks, as follows:
  a.  The External Circumflex, (Arteria  Circumflexa Externa,)
though most frequently a  branch of the profunda, sometimes
comes from the femoral  above or below it a short  distance.  It
goes immediately  outwards between the  rectus femoris muscle 
              FEMORAL ARTERY, AND ITS BRANCHES.           239

and the cruralis, giving off some  inconsiderable  ramifications.
While between these muscles it divides into two branches, one
of which ascends, and the other descends; the former is distri-
buted to the anterior margins of the gluteus medius and minimus,
to the capsule of the joint, and the parts about the trochanter
major, anastomosing with the gluteal and the ischiatic.   It is
said by Meckel, that these anastomoses have  been found much
dilated where the external iliac artery has been taken up.   The
descending branch is about  the  size of a crow quill, or even
larger; it first passes obliquely downwards between the rectus
femoris and the cruralis, it then descends vertically  under the
anterior margin of the vastus externus, between it and the cru-
ralis, to terminate at the knee, where it becomes superficial and
anastomoses with  the articular arteries.  It is, however, prin-
cipally distributed to the vastus externus and  to the cruralis.
   b. The Internal Circumflex Artery (Arteria Circumflexa In-
terna;) arises from the profunda, near the external circumflex,
generally below it, but  sometimes the reverse;  in some cases,
it comes from  the  femoral artery itself, near the crural  arch.
Lt passes transversely inwards, and dips into  the interstice be-
tween the pectineus and the psoas magnus, after having given
off some small twigs  to the heads of the adjoining adductors.
It then winds under the neck of the os femoris and divides into
two branches; the upper one goes to the capsular ligament of
the joint, to the obturator externus  muscle, anastomoses with
the  obturator artery, and sends a branch behind the adductor
brevis to the upper part of the adductor magnus:  the inferior
branch  is larger than  the other; it descends behind  the ad-
ductor magnus and is distributed in  branches to it, to the gra-
cilis, and to the hamstring muscles, sending upwards some rami-
fications (rami trochanteric!) to the parts about the trochanter
major, where they anastomose with the external circumflex ar-
 tery.
   c. Muscular branches of inconstant origin, and of inconsider-
 able size, are sent from the profunda to supply the anterior face
 of the adductor muscles.
   d. The Perforating Arteries (Rami Profundi Perforates) ob-
 tain the name from their perforating the adductor magnus, which
 they do near the linea aspera, so as to get to the back of the
 thigh.   They commonly are four in  number,  and as they come 
240                 CIRCULATORY SYSTEM.
off successively from the profunda, they are designated numeri-
cally.   In some cases, however, they are reduced to one, by be-
ing concentrated in a common  trunk, which, penetrating high
up the adductor magnus, and afterwards descending on its pos-
terior face, is dispersed upon the muscles on the back of the
thigh.
   The First Perforating Artery arises somewhat below the tro-
chanter minor, and penetrates the adductor magnus a little be-
low its  superior margin.  One of its branches ascends towards
the trochanter major, where it anastomoses with the external
circumflex and with  the gluteal, while  another descending  is
spent upon the heads of the flexor muscles of the leg.
   The Second Perforating  artery gets to the back of the thigh,
at the lower  margin of the  insertion of the gluteus magnus into
the linea aspera, being distributed in that region, and to the cor-
responding portion of the long head of the biceps flexor cruris.
   The Third Perforating Artery penetrates the Adductor  mag-
nus somewhat below  the commencement of the short head of
the biceps, and is dispersed  upon the adductor and the adjacent
portion of the flexor muscles.
   The  Fourth  Perforating Artery penetrates the  insertion of
the adductor magnus an ineh and a half above the opening in
it, for the femoral artery; it, in the same way, supplies the pos-
terior face of the  adductor and the adjacent muscles.

   As a summary, it will be readily understood that  the pro-
funda is, in this way, through the  external and the internal cir-
cumflex, and  through  the perforating arteries, distributed upon
all the large muscles of the thigh.

   After the origin of the profunda, the Femoral Artery gives
off, at  different points of its course to the opening of the ad-
ductor magnus, several twigs the size of a large knitting needle;
which  go to  the sartorius, the gracilis, the adductors, and the
extensors on the front of the thigh; but they are too inconstant
to require a more particular description.

   The Anastomosing Artery (Arteria Anastomotica) is the
last branch of the femoral, and  arises just before it perforates
the adductor  magnus.  It descends to the knee, in front of the 
POPLITEAL ARTERY, AND ITS BRANCHES.
241
tendon of the latter, concealed by the internal margin of the
vastus internus muscle.  It sends off many small twigs to the
adjacent muscles, and terminates below by anastomosing with
the interna] articular arteries.  It is about the size of a crow-
quill.

   The Popliteal  Artery (Arteria Poplitasa) is  the continua-
tion of the femoral, after the latter has passed through the ten-
dinous insertion of the adductor magnus ; and extends from this
point to the opening in the interosseous ligament of the leg,
just below the head of the  tibia.  It, first  of all, passes  from
the  internal  margin  of the os femoris, to the  notch between
the condyles; being there placed in the middle between the in-
ternal and the external hamstring muscles, and  surrounded by
a  mass of adipose matter which fills up the hollow of the  ham.
It is in contact, anteriorly,  with the knee joint, and a little be-
low the latter with the popliteus muscle, descending there be-
tween the heads  of the  gastrocnemius.  It is covered, in the
greater part of  its extent, posteriorly, by the  popliteal vein,
and  by the sciatic nerve, the latter being more superficial  than
the vein.
   The popliteal artery sends off some  small branches  to the
hamstring muscles, and to the parts contained between the lat-
ter,  which are too irregular and inconstant for description.
The following arteries, also, come from it:—

   1. The  Superior Internal Articular Artery (Art. Articularis
Superior Interna) arises at  or above the internal  condyle, and
frequently consists  in two  trunks.  It  passes through the ten-
don of the adductor magnus, just above the condyle;  it  then
begins to distribute itself in  branches, some of which are spent
upon the  lower part of the vastus internus muscle,  and others
upon the superior internal part of the knee joint.

   2. The  Superior External Articulating Artery (Art. Articu-
laris Superior Externa) arises  from  the  popliteal, somewhat
above the external condyle  of the os  femoris.  It winds, hori-
zontally, above the external condyle, around the bone, between
it and the lower part  of the biceps  flexor cruris, and is  then
distributed, also, in two orders of branches, some of which sup-
   Vol. II.—22 
242
CIRCULATORY SYSTEM,
ply the lower part  of  the vastus externus muscle, and others
the superior external portion of the knee joint.

   3. The Middle Articular  Artery (Art. Articularis Media)
is smaller than either of the above, and sometimes comes from
one of them, but generally from  the popliteal, on a  line with
the articulation of the knee.   It is distributed to the posterior
part of the capsular ligament, to the crucial  ligaments, and to
the corresponding adipose matter.

   4. The Inferior Internal Articular Artery (Art. Articularis In-
ferior Interna)  arises on a line with  the inferior  part of the
internal condyle, sometimes lower down.  Its origin is very
much concealed by the internal head of the gastrocnemius;  it
passes beneath the  latter, and then between the internal lateral
ligament of the knee and the head of the tibia; consequently, it
is covered by the internal hamstring muscles.   It afterwards
ascends towards the patella, and is distributed in  numerous
branches to the inferior internal part of the knee joint, and to
the adjacent portion of the tibia.

   5.  The Inferior  External  Articular Artery (Art. Articularis
Inferior Externa) arises near the last, below the ^external con-
dyle, being concealed by the belly of the plantaris.   It passes,
horizontally, or nearly  so, between the popliteus and the outer
head of the gastrocnemius, and afterwards beneath the tendon
of the  biceps and the external lateral ligament  of  the  joint,
around the external face of the head of the tibia.  It gives
small branches  to  these several parts, and is then distributed,
by two orders of  ramifications, to the superficial and  to the
more deeply seated parts at the external inferior portion of the
knee joint.

   These  several * articular  arteries  anastomose  freely with
each other, and  are  minutely  ramified on the knee  joint and
the contiguous structure.  They also  anastomose  with the
long descending branch of the  external circumflex of the thigh,
with the anastomotica of the  femoral, and  with  the tibial re-
 current. 
          ANTERIOR TIBIAL ARTERY, AND ITS BRANCHES.        243

  6. The Gastrocnemial Arteries (Arterice Gemellce) are two in
number, one for each head of the gastrocnemius.   They arise
commonly between the superior and the inferior articular arte-
ries, and  are  about  the same  size.   They penetrate into the
muscle, and supply it with  blood, terminating their course near
the lower part of its bellies.
   Moreover, some small branches, which go to the contiguous
muscles, are  frequently observed here; also, the nutritious ar-
tery of the tibia.  But their number and condition are very in-
constant.  Near the head of the fibula, branches  go from the
popliteal artery to the upper end of the soleus muscle.
   Generally, on a  level with the aperture in the upper part
of the  interosseous  ligament^ but sometimes  an inch or two
higher up, the popliteal artery terminates by dividing into two
large trunks, the Anterior and the Posterior TibiaL

   The Anterior Tibial  Artery  (Art.  Tibialis Anterior)  passes
forwards through the  foramen of the interosseous ligament,
just below the  head of the fibula, and runs down the front of
the leg and foot, as  far as the base of the metatarsal bone of
the great toe.   In  this course, its  relative situation is  as fol-
lows:
   It rests upon the front of the interosseous ligament  of the
 leg, on a line drawn from the middle anterior part of the head
of the fibula to the middle of the ankle joint.   Superiorly, it is
bounded on the tibial side by the tibialis anticus muscle, and on
the other by the extensor longus digitorum: lower down on the
leg, the  place  of the latter is  supplied by the extensor pollicis
pedis.   Somewhat above the ankle joint the artery, leaving the
interosseous ligament, rests upon the front of the tibia, and then
gets to the top  of the foot, between the  joint and the annular
ligament.  Under  the ligament it is crossed by the tendon of
the extensor pollicis, which gets to its inner side, and afterwards
continues so.   The anterior tibial  nerve adheres  to it, in its
whole length.
   The following  branches come from the  anterior tibial ar-
tery:

   1. The Recurrent Tibial (Art.  Tibialis Recurrens) ascends
through the upper  extremity  of the tibialis  anticus  muscle, 
244
CIRCULATORY SYSTEM.
having come off from the anterior tibial immediately upon the lat-
ter getting to the front of the leg.   Several small ramifications
pass from it to the heads of the contiguous muscles on the tibia,
and to the lower part of the knee joint, where it anastomoses
with the lower articular arteries of the knee.

   2. Several small  arterial twigs are afterwards sent  to the
muscles and to the periosteum of the leg, as the  anterior tibial
descends, but they are  too  inconstant in size and position  to
require description.

   3. The Internal Malleolar Artery (Art. Malleolaris Interna)
arises from the anterior  tibial, an inch or two above the ankle
joint.  It descends, inwardly, between the tibia and the tendon
of the tibialis anticus, and, having gained the  internal  malleo-
lus, is distributed  by branches upon  it and  upon the adjacent
portion of the articulation.

   4. The External Malleolar Artery (Art. Malleolaris Externa)
consists most commonly  in two arterial twigs of small size, but
frequently in one only.  It arises in  front of  the  ankle  joint,
and going outwardly between it and the tendons of the extensor
digitorum longus, is spent upon the external face of the articu-
lation, where it inosculates with the peroneal artery.
   This artery is sometimes of considerable size,  in which case
it  also supplies the outer part of  the tarsus, and  is a  substitute
for the next.

   5. The Tarsal Artery  (Arteria Tarsea) arises  from the an-
terior tibial, somewhat below the ankle joint near the scaphoi-
des, and, going outwardly beneath the extensor  brevis  digito-
rum muscle, it is distributed in branches near the external an-
kle, and upon the outer upper surface of the tarsus.   It anas-
tomoses with the external malleolar, with the external plantar,
and with the metatarsal artery.
   Some small branches also pass from the anterior tibial at this
point to the upper internal face of the tarsus.

  G. The Metatarsal  Artery (Art. Metatarsea) arises just below
the last.  It is directed forwards  and outwards beneath the ex- 
POSTERIOR TIBIAL ARTERY.               245
tensor brevis muscle, and forms a sort of arch at the roots  of
the metatarsal bones.  It furnishes several ramifications to the
upper surface of the tarsus and the contiguous parts; amongst
them is an interosseal artery for each of the three outer interos-
seal spaces.   These  arteries  communicate,  by small anasto-
moses, with the arteries of the  sole of the foot, both at the bases
and at the ends of the metatarsal bones, and  terminate in front
by supplying the backs of the small toes.
  This artery is sometimes  a branch of the tarsal,

  7. The Dorsal Artery of the Great Toe (Art. Dorsalis Hal-
tucis) arises from the  anterior  tibial  at the root of the first  me-
tatarsal bone.  It runs along the superior face of the first me-
tatarsal interval,  and  having reached the anterior end of it, di-
vides into two branches, one of which goes  to the back of the
great toe and the other to the tibial margin of the next toe.
  The Anterior Tibial, in its course from the ankle joint to the
base of the first metatarsal bone, is sometimes called Pedal (Ar-
teria Pedicea;) at the posterior end of the first metatarsal inter-
val, being still of considerable size, it sinks down to  the sole  of
the foot, and joins itself  to the external  plantar  artery at this
point.
  It frequently happens that the anterior tibial being small  in
its course down the leg,  is joined by the continued trunk of the
peroneal, which perforates the interosseous ligament somewhat
above the ankle joint.  Afterwards the trunk formed by this
union, being of considerable  size, follows the course and has
the distribution mentioned.
  The Posterior Tibial  Artery (Arteria  Tibialis Postica)  is
sometimes called, at its commencement, till it gives  off the pe-
roneal, tibio-peroneal; it extends from the head of the tibia  to
the  sinuosity of the os calcis,  in a line  from the middle of the
ham to the internal ankle.  It is at the tibial side of the back
of the leg, on  the posterior  face of the flexor longus digitorum
muscle;  and covered  by the  fascia of the latter.   In the two
superior thirds of its course, it is concealed behind by the gas-
trocnemius and the solaeus  muscle: in the inferior  third, it  is
at the internal margin of the tendo-achillis.  At the ankle joint,
before it passes into the sinuosity of the os calcis, it  is between
the  tendon of the tibialis posticus and that  of the  flexor lon-
                             22* 
246
CIRCULATORY SYSTEM.
gus pollicis pedis, being covered by the laciniated ligament.   It
is accompanied, at its external margin, by the posterior tibial
nerve.
  The posterior tibial  artery is distributed  after the following
manner:—

   1. The Peroneal Artery (Arteria Peronea) is its first branch
of any importance, and is but little smaller  than the continued
trunk.  It arises an inch or two  below the  origin of the ante-
rior tibial, and extends, on the posterior face of the leg, to-the
external ankle.  It is, in some  measure, concealed by the pos-
terior side of the fibula, being  placed there between the origin
of the flexor longus pollicis muscle and the external edge of the
tibialis posticus.  It is covered behind by the flexor longus pol-
licis, by the soleus, and by the  gastrocnemius; it is, therefore,
deep and of extremely difficult access in the living body.
   In this course, it sends small branches to  the gastrocnemius,
to the soleus, and to the other contiguous muscles on the back
of the leg.  After having descended two-thirds of the length  of
the fibula, it divides into an  anterior and a posterior branch.
The former traverses the  interosseous ligament, and, descend-
ing in front of it, covered by the muscles which arise from the
lower part of  the fibula, is distributed upon the upper external
part of the foot near the ankle joint.  The posterior branch con-
tinues in the primitive course of the peroneal artery at the in-
ternal posterior margin of the fibula, and descending behind the
tibio-peroneal  articulation, reaches the  external face of the  os
calcis: it detaches several small ramifications to the contiguous
muscles;  and, upon  the os calcis, is  divided into twigs which
supply the adjacent parts and  the integuments below the exter-
nal ankle.

  2. In the  descent of the posterior tibial artery to  the hollow
of the os calcis, it  detaches several small muscular branches,
principally to the tibialis posticus, and to the flexors of the toes.
One twig, which is the nutritious  artery of the tibia, comes from
its upper part when not furnished from the popliteal artery, and
enters the foramen on the posterior surface of the bone.
  While the posterior tibial is in the hollow of the os calcis,
hot ween  it and the abductor muscle of the great toe, it furnishes
some small twigs to the contiguous muscles, and to the integu- 
          POSTERIOR TIBIAL ARTERY, AND ITS BRANCHES.       247

ments of the sole of the foot; it then divides into two branches,
the Internal and External Plantar Artery.

   The  Internal  Plantar Artery (Art.  Plantaris Interna)  is
much smaller  than  the other.   It advances between the abduc-
tor pollicis pedis and thQ internal inferior margin of the sole of
the foot, and terminates at the anterior end of the  first metatar-
sal bone, by joining the internal  digital artery of the great toe.
In this  course, it sends, continually, small ramifications to the
muscles of the great toe and to  the flexor brevis digitorum pe-
dis.  One of the largest of these ramifications comes off near the
os scaphoides, and cruises along the internal margin of the ab-
ductor pollicis to its anterior end;  another becomes  superficial
on the sole of  the  foot, between the abductor  pollicis  and the
flexor brevis digitorum, and goes forward as far as the other.

   The External Plantar  Artery (Art.  Plantaris Externa)  is
the continuation of the posterior tibial, and diverges from the
internal plantar towards the outer margin of the sole of the foot,
between the flexor brevis digitorum pedis and the flexor acces-
sorius.   Having  reached the internal margin  of the abductor
minimi digiti, it advances along the latter to the base of the me-
tatarsal bone  of the fourth  toe;  it then makes a curvature for-
wards and inwards across the metatarsal bones, between the ten-
dons of the flexor longus digitorum and the interosseous muscles,
to the  first metatarsal interval, where it is joined by  the an-
terior tibial artery from  above.   This curvature is  the Arcus
 Plantaris, of which the concavity is behind and inwards.
   The external plantar artery is distributed as  follows:—
   Shortly after its origin, it detaches a branch which goes  back-
wards and outwards,  and which, keeping close to the os calcis
in front of its tuberosity, is distributed to the heads of the mus-
cles arising from it, and  to the outer surface of the heel; it also
 sends an arteriole  along the external edge of the abductor mini-
 mi digiti.
    At the base of  the  fourth metatarsal  bone, arises a branch
called the External Digital Artery of the Little Toe.   It goes
 at first deeply along  the internal margin of the muscles situ-
ated on ihe fifth metatarsal bone, and, afterwards, at the head 
248
CIRCULATORY SYSTEM.
of the latter, it gets between them and  the bone, and is distri-
buted along the external margin of the little toe.

   The four Digital Arteries of the foot arise  next  successively
from the arcus plantaris, at or near the  metatarsal intervals.
They run along the inferior surface of the  interosseous muscles,
getting to the bases of the first  phalanges  above the transver-
salis pedis.   Each artery there bifurcates, so as to supply the
opposed  surfaces of the adjacent toes, in the same way that the
digital arteries of the hand are distributed.
   The  digital artery of the first  metatarsal  interval which
comes from the internal extremity of the arcus plantaris, where
the anterior tibial artery joins the  latter, goes forwards con-
cealed by the flexor brevis of the great toe: just behind the se-
samoid bones, it sends a branch which supplies the  internal side
of the great toe, being its internal digital artery, and  anastomoses
with the internal plantar  artery.  What remains  of it, is still
a trunk  of considerable magnitude, which  advancing  to  the
space between the first phalanx of the great toe and of  the toe
next to it, there  bifurcates,  as  mentioned, so  as to supply the
opposite sides of these two toes.

   The Perforating Arteries, as they are called, are of two kinds,
the anterior and the posterior.   The former arise from the con-
vexity of the plantar arch, and  being  destined  principally to the
interosseous muscles, anastomose at the anterior end of the lat-
ter with  the branches from the metatarsal  artery, which supply
their superior surface.   The posterior perforating arteries come
also  from the plantar arch, and penetrating the posterior end of
the interosseous  spaces, anastomose also  with  the metatarsal
arteries on the dorsum of the foot.
  The preceding trunks of the internal and of the external plan-
tar arteries are the  principal  ones which  are found in the bot-
tom of the foot, but from them  there  arise  an  immense number
of arterioles; which, descending vertically between the inter-
stices of the muscles and of the aponeurosis  plantaris, supply
the adipose matter and the skin of the sole of the foot, so as to
render them extremely vascular. 
OF THE VEINS.
249
                     CHAPTER  III.

                       OF THE VEINS.

   The veins of the body, assembling from different points, unite
 successively into the ascending and  into the descending vena
 cava, which discharge  their  blood into the right auricle of the
 heart.  The veins of the head, of the upper extremities, and of
 the thorax, run into the descending cava, while the veins of the
 abdom.en and  of the lower  extremities concur  to form the as-
 cending cava.

         SECT. I.--OF THE VEINS OF THE HEAD AND NECK.

   Many  of these veins are  described elsewhere with  the en-
 cephalon and  with the eye, to which account  the reader  is
 referred.  The others are more superficial, and arise as follows:

   The  Facial Vein (Vena  Facialis) observes the course of the
 facial artery, being placed  behind the latter.   It arises upon the
 forehead  by a considerable number of roots, which  unite into a
 single trunk called  the  frontal vein.   This vein descends from
 the forehead, over the root of the nose, along the internal can-
 thus of the  orbit.  It there receives  re-enforcements from the
 eyelids, and anastomoses with the ophthalmic veins;  descending
 afterwards,  in the same way with the facial artery, and taking
 the name of facial vein, it  receives successively the veins from
 the nose, from the outer side of the  orbicularis  palpebrarum,
 from the upper and lower  lips, and from  the  muscles and the
 integuments of, the face.  It  descends to the neck at the ante-
 rior margin of the masseter  muscle, and is then augmented by
 the ranine, the submental,  and the inferior palatine veins, and
 immediately afterwards goes into the internal or the external
jugular  vein.

  The Ranine  Vein (Vena  Ranina) arises at  the point of the
tongue,  and  then goes  along its  under surface,  where  it can 
250
CIRCULATORY SYSTEM.
be readily seen by turning up the end of the  tongue.   It joins
the facial near the posterior margin of the mylo-hyoideus mus-
cle.

   The Submental Vein (Vena Submentalis) arises by ramuscles
from the sublingual and the submaxillary gland, and from the
contiguous muscles.  It joins the facial vein  a little below the
last: sometimes it runs into the superior thyroidal vein.

   The Inferior Palatine Vein (Vena Palatina  Inferior) arises
principally from the soft palate and from the tonsil gland, but
receives  a few  twigs  from  the contiguous  parts.  It corres-
ponds with the inferior palatine  artery, a branch of the dorsal
lingua], (Dorsalis Linguae;)  and descends  the  pharynx along-
side of it, and terminates in  the trunk of the  facial near the
last.

   The Lingual  Vein (Vena  Lingualis)  has  its origin from a
plexus of veins situated on the root of the tongue under its lining
membrane,  between the  epiglottis and  the  foramen  caecum:
branches are also sent to it from the  muscular  structure of the
tongue, from the  sublingual gland  and from  the adjacent  mus-
cles, and it anastomoses with the vena ranina.   It goes back-
wards between the  hyo-glossus and the mylo-hyoideus muscle,
along the superior margin of the os hyoides, and  then  dis-
charges into the internal jugular vein near the facial.

   The Pharyngeal Vein (Vena Pharyngea) arises from a plexus
of veins belonging  to the pharynx, and  discharges either into
the lingual or into the internal jugular near it.

   The Superior Thyroid Vein (Vena Thyroidea Superior) cor-
responds with  the  distribution of the superior thyroid artery,
in the origin  of its  primitive  roots.  Having collected the lat-
ter into one or more trunks,  it  passes upwards and backwards
beneath the  sternohyoid and thyroid muscles, and discharges
itself into  the upper part of the internal jugular, or into one of
the large branches of the external jugular.

   The Occipital Vein  (Vena Occipitalis)  arises from the 
                 VEINS OF THE HEAD AND NECK.              251

 branches of the  occipital  artery, and following the  course of
 the  latter,  beneath the muscles  connected with the mastoid
 process of the temporal bone, it is discharged into  the upper
 part of the internal jugular or of the external; more rarely into
 the  latter.

   The Diploic Veins (Vence Diploicce) have been described in
 the  account of the  bones of the cranium as situated between the
 two tables in the diploic structure, and commence by very fine
 capillary tubes from its lining membrane.  The one in the fron-
 tal bone discharges itself into the frontal  vein, that in the occi-
 pital bone into the  occipital vein, and the two in "the parietal
 bone into the deep  temporal veins.  They do not open each by
 one orifice, but by  several, which makes their terminations not
 very distinct or abrupt: besides which, they communicate freely
 by a crowd of ramuscles, with the veins  of the scalp on the
 outside, and with those of the dura mater internally.

   The Superficial  Temporal Vein (Vena Temporalis Superfi-
 cialis) corresponds with the  temporal artery, and takes its rise
 from the  terminating ramifications of the latter.  It  is imme-
 diately below the skin.   Its branches communicate freely with
 each other, and  with  the branches of the frontal and of the
 occipital  vein:  at the zygoma  it receives the trunk of the
 Middle Temporal  Vein, which,'collecting the blood  from the
 temporal muscle  and other parts  within the zygoma, perforates
 the temporal fascia to  discharge  itself into the superficial tem-
 poral vein.

   The Temporal Vein,  (Vena Temporalis,)  which is formed
 by the junction of  the Middle  and  the Superficial Temporal,
 descends  over the root of the zygoma, in company with  the ar-
 tery, and penetrates, like the latter, through the substance of
 the  parotid gland.   It is joined, near the neck of the lower
jaw, by  the internal maxillary vein.  It  is also joined, in its
 descent  through  the parotid gland, by the anterior auricular
 veins, by the parotid veins, and by the transverse facial, all of
 which correspond with the arteries of the same name.'  The
 temporal  vein, on issuing from the parotid gland, immediately 
252
CIRCULATORY SYSTEM.
 afterwards becomes the External jugular; but, occasionally, it
 ends wholly, or in part, in the Internal jugular.

   The Internal Maxillary Vein (Vena Maxillaris Interna) is de-
 rived from the terminating ramifications of all the arteries into
 which the  internal maxillary is divided; it is, therefore, com-
 posed of the spheno-palatine vein, which brings the blood from
 the nose, of the  infra-orbital, of the  pterygoids, inferior  max-
 illary, deep-seated  temporal, and so forth, with the exception
 of the vein, which  might  belong to  the middle artery of  the
 dura mater, but which does not exist according to Portal and
 to Hippolytus Cloquet.   By the aid of the spheno-palatine vein,
 the  internal maxillary  communicates with  the sinuses in  the
 bottom of the cranium,  by  branches, called the Emissary Veins
 of Santorini,* which  pass  through the foramen ovale, rotun-
 dum,  and  spinale.   It  also communicates with the plexus of
 veins on the side of the pharynx.

   The External Jugular Vein (Vena Jugularis Externa)  is ge-
 nerally the  continuation of the  temporal.  It  descends on  the
 neck almost vertically,  between the platysma  myodes and  the
 sterno-mastoideus, in the direction of  the fibres of the first, and
 crossing those of the latter obliquely.  Just behind the clavicle, at
 the external margin of  the  sterno-mastoideus, it opens into the
 subclavian vein, in front of the scalenus anticus muscle.  Some-
 times, instead of one trunk only, there are two or three, which
 unite at a variable distance above  the subclavian.   This vein
 varies also  in its size,  and in the  branches  from which it is
 made up: sometimes it  receives the facial vein, and on other
 occasions the latter runs,  as  stated,  into the internal jugular.
 The  condition and  arrangement of the internal and  external
jugulars  are, indeed, so inconstant,  in regard to the trunks
that  compose them,-that it is  scarcely possible to give  more
than a very general description  of them with  tolerable accu-
racy.
  The external jugular, in  going down the neck, anastomoses
more or less with the internal jugular, either directly or by  its
branches: one of these  anastomoses is found near the angle of
* Obs. Anat. chap. iii. p. 74. 
                VEINS OF THE HEAD AND NECK.             253

the lower jaw, about the trunk of the facial vein, and is so large
as to explain the difference of opinion among anatomists in re-
gard to the latter's termination.  Sometimes the occipital vein,
or a large  trunk from it, joins the external jugular.  At  the
lower part of the neck, the  external jugular is augmented by
the superficial cervical veins.  Some of these come from the
lower part of the neck, near the shoulder, and join the jugular
just above  the clavicle;  others are placed on the lower front
part of the  neck, above the sternum, and there form with each
other a remarkable  and an irregular plexus, consisting in nu-
merous meshes.   It frequently happens  that the external jugu-
lars of the two  sides, just before they  terminate, anastomose
with each other by a large horizontal  trunk, which runs  jutt
above the end of the sternum, in front  of the sterno-mastoid,
sterno-hyoid, and  the sterno-thyroid  muscles:  this  trunk, on
other occasions, goes more deeply, and behind these muscles,
from  one subclavian vein to another, or to a jugular; its mode
of attachment is, indeed, much varied: when it exists, however,
it frequently receives several of the superficial  veins of the
neck, and the inferior thyroideal.

   The Internal Jugular Vein (Vena Jugularis Interna) extends
from the basis of the cranium to the internal margin of the  first
rib, at the insertion of the scalenus anticus muscle.  The lateral
sinuses of the dura mater, receiving ultimately all the blood of
the brain, of the eye, and a portion of that of the  nose, convey
it from  the cranium through the posterior  foramina lacera,
where they are joined to the upper end of  the internal jugular
veins, the lining membrane of each sinus being continuous  with
that of its  respective vein.   Each vein  is somewhat enlarged
at its commencement, which is therefore called its Gulf or Sinus;
the right vein is frequently larger than  the left.   The internal
jugular then descends in front of the transverse processes of the
vertebrae of the neck, on the outer  side of  the internal  end of
the primitive carotid artery, and of the pneumogastric nerve.
It is concealed above by the  styloid  process of  the temporal
bone,  and  the muscles belonging to it;  it is crossed, half  way-
down the neck, by the omo-hyoideus muscle; and, in the great-
er part of its course, is  beneath, and nearly parallel with the
anterior edge of the sterno-mastoideus.  Having got behind the
   Vol. II.—23 
254
CIRCULATORY SYSTEM.
sternal  end of the clavicle, it is joined at the internal edge of
the scalenus anticus by the subclavian vein, and the union of
the two forms the vena innominata.
  The internal jugular receives frequently the large anastomotic
branch, just alluded to, from the external jugular, at the  under
margin  of the parotid gland, between the digastric muscle and
the lower jaw, and it is in  this vicinage that it is generally re-
enforced by the  Occipital;  the  Lingual;  the Facial;  the  Pha-
ryngeal ; and the Superior Thyroidal Veins, that have been de-
scribed.

  The Vena Innominata, or Brachio Cephalic Vein, is the trunk
formed on either side by the junction of the  subclavian with the
internal jugular.  On the right side it looks  like the continua-
tion of the internal jugular, and  descends  in contact with the
right  pleura, behind the right side of the sternum, for the dis-
tance of an inch  or thereabouts.   On the left side it crosses be-
hind the superior end of the  sternum, descending  obliquely in
this course, from left to right, until it joins the trunk on the
right side.   It lies in front of the great vessels proceeding from
the arch of the aorta; and is much longer than the trunk  of the
other side.   A common name for it is the Transverse Vein.
  The Vena Cava Superior, or  Descendens, arises  from the
junction of the two venae innominatae.  It  begins between the
cartilage of the  first rib on the right side,  and the arph of the
aorta, and  descends  to the superior posterior part of the right
auricle, into which it empties itself.   Its course is not entirely
vertical, but inclining somewhat to  the left  side and forward.
It is about  three inches long.  The superior third of it is free,
and is in contact on the right with the pleura, and on the left
with the arteria  innominata;  the remaining portion of it is  in-
vested by the pericardium, and has the aorta on its left anterior
face.*

  The following venous trunks discharge into  the venae  inno-
minatae, or into the descending cava.  The Inferior Thyroidal;
the Vertebral; the Superior Intercostal; the Internal Mammary;
the Vena Azygos, and some others of smaller size.

  * In some very rare cases there have been two descending venae cavae, one for
the right side and the other for the left.  J. F. Meckel. 
VEINS OF THE HEAD AND NECK.
255
  1. The Inferior  Thyroid  Vein (Vena Thyroidea  Inferior)
arises from the inferior part of the thyroid  gland, by many
small roots, which anastomose with those of the opposite side.
It descends in front of the trachea, involved in the loose cellu-
lar  and fatty matter lying upon it, and empties itself into the
left brachio-cephalic vein, or Transverse Vein. '
  There is  occasionally another thyroid vein, called  the mid-
dle, which discharges itself into the lower part of the internal
jugular,

  2.  The Vertebral Vein (Vena V-ertebralis)  is placed in the
same canal with the vertebral artery.  At its upper extremity
it anastomoses with the occipital sinus, by a branch lodged in
the posterior condyloid foramen.  In its descent of the canal of
the transverse processes,it communicates at each intervertebral
foramen with the vertebral sinuses, and also receives  a branch
from the muscles of the neck.   It issues at the sixth transverse
process, and going on the right side behind the subclavian ar-
tery, but on the left, in front  of it, it is, finally, emptied into the
commencement of the vena innominata.

  3.  The  Superior  Intercostal Vein  (Vena  Inlercoslalis Supe-
rior) is on  the  right side an inconsiderable trunk, sometimes
deficient, which commences  by branches belonging to the two
first intercostal spaces, and  empties into the vena  innominata
just below the vertebral On  the left side it is much larger,
and arises from the six or eight superior intercostal spaces. It
lies on the left side of the bodies of  the upper dorsal vertebrae,
and at each intercostal space, as it ascends, receives its contri-
bution of an intercostal vein,  corresponding with the intercostal
artery; it also receives branches from the oesophagus, and about
the third dorsal vertebra the left bronchial vein  is discharged
into it.   Issuing from  the thorax above, it discharges into the
left vena innominata near its commencement.

   4.  The Internal Mammary Vein (Vena Mammaria Interna)
arises from the terminating branches of the internal mammary
artery, and in its situation and course corresponds with the lat-
ter.  It  is re-enforced by small branches from the  diaphragm,
the pericardium, and the thymus gland.  Each internal mam- 
256
CIRCULATORY SYSTEM.
 mary vein discharges itself on its respective side into the vena
 innominata near the superior intercostal.

   5. The Vena Azygos is placed in the  posterior mediastinum,
 on the right anterior margin of the Dorsal Vertebrae, and dis-
 charges itself in making an arch forwards over the root of the
 right lung, into the descending cava, just above the introduction
 of the latter into the pericardium.   Its orifice there is supplied
 with a membranous duplicature or valve, which prevents the
 blood once discharged from re-entering it.  The valve is some-
 times double, and also somewhat removed from the orifice.   It
 was the observation of these valves,  first of all, which called
 the aUention of Sylvius and  of Charles Etienne to their exist-
 ence in other veins.
   This vein begins in the abdomen, either by an anastomosis
 with the ascending cava, or with the upper lumbar vein; it then
 ascends into the  thorax through the  aortic orifice of the dia-
 phragm, and continuing to mount upwards beneath the pleura
 it lies on the right side of the  thoracic  duct, and crosses in front
 of the intercostal arteries of the right side.  In this course, it
 receives from the ten inferior intercostal spaces of the right side,
 their respective intercostal veins corresponding in their origin
 and course with the intercostal arteries.  About the sixth ver-
 tebra of the back, it receives a trunk (Vena Hemiazygos) which
 is formed from the four or six lower intercostal veins of the left
 side, and commences in the abdomen,  also, by anastomosis with
 the left emulgent vein or  the left superior lumbar, and which
 gets into the thorax either through the aortic orifice of the dia-
 phragm, or through a special opening  to the  left  of it.  The
 vena azygos  also receives some small ramifications from the
 oesophagus, and near the fourth dorsal vertebra, the right bron-
 chial vein is discharged into  it.   Other small ramifications join
 it from the parietes of the descending cava, of the aorta, and  of
 the right pulmonary artery.   Branches also proceed to it, or to
 the intercostal veins, from the interior of the vertebral canal  at
each intervertebral foramen.
  This vein is commonly spoken of by anatomists, as forming
a great anastomosis between the ascending and the descending
cava.  The tendency to establish this anastomosis is strikingly
confirmed by a  preparation made by myself, when I was a stu- 
VERTEBRAL SINUSES.
257
 dent in this institution, in 1813, and now in the Anatomical Ca-
 binet, where the ascending cava, instead of emptying, as usual,
 into  the lower part of the right auricle, ascended on the  right
 side of the dorsal vertebrae, and supplanting in situation and of-
 fice the vena azygos, discharged itself into the descending cava,
 in a manner corresponding with the vena azygos, by making a
 curvature forwards over the root of the right lung.

   The Sinuses  of the  Vertebral  Column*  (Sinus  Columnar
 Verlebralis) are situated in the vertebra] cavity, on the poste-
 rior face of the bodies of the vertebrae, and in front of the dura
 mater of the  spinal marrow.  They  are two long veins, one
 at each margin of the posterior  vertebral ligament, and  extend
 from the foramen magnum  occipitis to the inferior end of the
 sacrum.  They are maintained in  their places by a loose cel-
 lular tissue between the bones and the dura mater, and, there-
 fore, unlike the sinuses  of the brain,  are entirely  independent
 of the dura mater.
   These sinuses are small where they begin in the sacrum, and
 are there merely two  cylindrical veins surrounded  by  the loose
 cellular matter, and which have  an anastomosis between them.
 In ascending  the spine they enlarge,  but not continually, as
 they are somewhat smaller in the cervical  than in the dorsal
 vertebrae.  On the body of each  vertebra they are rather larger
 than on the intervertebral substance:  this gives them a knotted
 appearance, which  is especially  distinct in the loins.
   At  the middle of each vertebra they are joined to  one ano-
 ther  by transverse  branches, which pass beneath the posterior
 vertebral ligament,  and  receive the veins belonging to the  cel-
 lular structure of  the bone.  Externally, they communicate
 with the vertebral veins in the transverse processes of the neck,
with the intercostal, and with the lumbar veins, as  an opening
occurs between the adjacent vertebrae. They also receive many
delicate veins  from  the dura mater of the spine.  These  two
trunks terminate  at  their upper end by an anastomosis, through
the anterior condyloid foramen, with the internal jugular: they
also  terminate by anastomosis with the anterior occipital sinus
and with the vertebral veins.

       * G, Breschtt,  Essai sur les Veines du rac'.iis.  Paris, 1819.
                            23* 
258
CIRCULATORY SYSTEM.
  From the arrangement of these sinuses, it appears that each
bone of the spine has its  own venous system or circle; which
also is the case in regard to the corresponding section of me-
dulla  spinalis in early  life, when it occupies the whole length
of the spine.  Each of these circles, by the freedom of their
anastomoses, therefore, forms a link in  a long  chain of venous
circles belonging to the structure of the spine.


      SECT. II.--OF THE VEINS OF THE UPPER EXTREMITIES.

   The veins  of the upper extremities are superficial and deep-
seated, and arise from the distribution  of the arteries.
   The Deep-seated Veins are found in  company with each ar-
terial ramification, there being two veins to one artery gene-
rally.   We thus have them observing the course of the arteries
of the hand,  of the fore arm, of the arm, and  of the shouldef.
At the bend of the arm, the two radial  and the two ulnar veins
coalesce into the two brachial veins, which attend the brachial
artery, one on each of its sides, and at intervals throw anasto-
motic branches across it.   Sometimes, but one of these trunks
exists, with the exception of the lower part of the arm, where
there are most commonly two.   The  trunk (or trunks, as the
case may be,) is joined  by the basilic  vein, at a point varying
from the middle of the arm to the axilla. These venae comites,
or satellites, are invariably called after the arteries which  they
 attend, and having  no difference from  the latter in relative si-
tuation, a farther description of them may be  dispensed with.

   The Superficial Veins lie between the skin and the brachial
 aponeurosis, and  are  considerably larger than  the preceding.
 Their earliest roots are seen on the back of the fingers;  they
 then appear on the back of the hand, on the  posterior face  of
 the lower end of each  interosseous space.  There are common-
 ly six trunks in all: the one on the ulnar side  of  the hand, and
 the  three next to it, converge towards the middle of the  back
 of the carpus into a single trunk; the two others, one of which
 comes from  the thumb and the other from the back of the fore-
 finger, converge to  the outer end of the carpus, and  there form
 a single trunk  also.  Between these several  trunks, there  are 
VEINS OF THE UPPER EXTREMITIES.
259
frequent anastomoses, and they, finally, assemble into two prin-
cipal branches called the Cephalic and the Basilic Vein.

  The  Cephalic Vein (Vena Cephalica, Radialis Cutanea)
is the trunk which comes  from the* thumb and from the fore
finger,  and has at first the name of Cephalica  Pollicis.  It
ranges along the anterior and radial margin  of the fore arm,
and receives, continually, an augmentation from small collateral
branches on the back  of the  fore arm.  Having  reached the
bend of the arm, it then ascends along the external margin of
the biceps  flexor cubiti till it reaches the lower margin of the
pectoralis  major muscle; it then rises  superficially along the in-
terstice between this muscle and  the deltoid, to within eight or
ten lines of the clavicle, where it  dips down to join the  axillary
 vein.   Along the arm, it receives some small secondary cuta-
 neous branches.

   The  Basilic Vein  (Vena Basilica, Cubitalis Cutanea) is
 larger than the cephalic, and begins by the trunk which comes
 from the ulnar side of the back of the hand, and is first called
 the Vena Salvatella.   On the fore arm, the basilic  frequently
 consists in two long trunks, fhe anterior and the posterior; in
 this case,  the posterior is the principal one, and runs along the
 internal posterior edge of the ulna until it comes to the bend of
 the arm; it then mounts over the latter, rising obliquely in front
 of the  internal condyle.  The anterior branch begins  near the
 palm of the hand, runs up in front of the ulnar side of the fore
 arm, and  discharges itself into the median basilic vein  over the
 brachial artery in front of the bend  of the  arm.  These two
 trunks, or one as the  case may be, receive the cutaneous veins
 belonging to the ulnar side of the fore arm.
   Above  the elbow joint, the basilic gets  below the fascia of
  the arm at the inner edge of the biceps, and about the middle
  of the arm becomes, by its junction with the venae satellites,
  the Brachial Vein; but sometimes, as mentioned, this  junction
  occurs much higher up.

    The Median Vein (Vena Mediana) arises, by branches, from
  the wrist, from the palm of the hand, and from the middle ol
  the front  of the fore arm.   It forms a trunk which ascends in 
860
CIRCULATORY SYSTEM.
  front of the fore arm, and which» a few inches below the bend
  of the arm, divides into two.  One branch runs outwardly, in
  ascending for an inch or two, and joins, at the outer side of the
  bend of the arm, the cephalic vein; it is called, therefore, the
  Median Cephalic.  The other branch continues to ascend, and,
  crossing obliquely the direction of the brachial artery, it re-
  ceives, near the latter, the anterior trunk of  the basilic vein,
  and somewhat above the bend of the arm, runs into the proper
  basilic vein: it is called the Median Basilic.
   There is frequently a departure from the preceding arrange-
  ment of the median vein; the most common is where a trunk
  begins from the  cephalic, below  the bend of the arm, and runs
  obliquely in front of the latter to join the  main trunk  of the
  basilic above the elbow joint.  This oblique trunk stands in the
 place of median  cephalic and median basilic, and receives suc-
 cessively the median, the  anterior, and the posterior basilic.
 It is frequently the median itself,  and has a short anastomosis,
 in such case, with the cephalic vein.

   The Superficial Veins anastomose frequently with each other,
 so that, when  they are all fully injected, a plexus of veins  is
 found immediately  beneath the  skin  of the upper extremity
 from one end to  the other.  The Venae Satellites also anasto-
 mose frequently by branches which  cross the artery to  which
 they belong.  At the bend of the arm, at the wrist, and  in  dif-
 ferent places,  there are also  anastomoses between the deep-
 seated and the superficial veins.

  The Axillary Vein (Vena Axillaris) results from the union of
 the basilic  with the brachial vein.  It is below and in front of
 the axillary artery, being included in the same sheath with it,
 and also involved with the axillary plexus of nerves.   It retains
 its name from  the lower  margin of the arm pit  to the  under
 surface of the clavicle, where, like the artery, it is then called
 subclavian.  In this  course it is joined near the points where
 the corresponding arteries are given off, by the Anterior and
 the  Posterior Circumflex Vein;  by the Scapular; and by the
External Thoracics.

  The Subclavian Vein (Vena Subclavia) extends from the ter- 
               VEINS OF THE LOWER EXTREMITIES.            261

mination of the axillary to the vena innominata,  where  the
latter is constituted by the junction of the internal jugular with
the subclavian.  In its course it goes under the subclavian mus-
cle, and is in front of the subclavian artery from the beginning,
but near it: afterwards it is separated from the artery by the
latter going between the anterior and the middle scalenus mus-
cle;  whereas  the vein  runs over  the anterior end of the first
rib, in front of the insertion of the scalenus anticus.
  The Subclavian Vein is joined by some branches coming
from the shoulder and from the lower part of the neck; and, at
the outer margin of the origin of the sterno-mastoid muscle, it
is augmented  by the addition to it of the external  jugular.  It
terminates at  the internal  margin of the scalenus anticus, as
mentioned in the vena innominata.
         SECT. III.--VEINS OF THE LOWER EXTREMITIES.

  The veins of the lower extremities, like those of the upper,
are deep-seated and superficial.  The former follow the course
of the arteries, and are the venae satellites; there being, for the
most part, two veins for every artery as far up as the ham, and
also as regards the muscular branches of the thigh.  These venae
satellites adhere closely to the  artery, and are  separated from
each other by the latter.   They also have frequent anastomoses
with each other across the artery.

  The Popliteal Vein (Vena Poplitea) is  a single trunk formed
by the union of the anterior tibial, the posterior tibial, and the
peroneal veins.   It begins on the posterior part of the head of
the tibia, and extends upwards through the ham to the perfora-
tion in the adductor magnus muscle, which transmits the femo-
ral artery.   It is  situated on the posterior face  of  the popliteal
artery, to which it closely adheres; and behind it is the popliteal
nerve, the continuation of the great sciatic.

  The Femoral Vein (Vena Femoralis) is the continuation up-
wards of the popliteal: it at first is placed behind the artery,
but in a short space it gets to its interior  face, and  continues to
adhere to it, in that situation, up to Poupart's ligament, where 
262
CIRCULATORY SYSTEM.
it becomes the external iliac vein.  At the usual distance below
the groin, where the arteria profunda is given off, the femoral
vein receives the vena cruralis profunda, which is derived from
the branches of this artery, and is rather more superficial than
it;  the two, however, adhere closely together.   Just  below
Poupart's ligament the  femoral vein receives several small
branches of veins corresponding  with the external pudic arte-
ries.

   The Small Saphena (Vena Saphena Minor, Externa) com-
mences by several small  branches near the external side of the
top of the foot, and the  external ankle;  a  trunk  is formed by
them  behind the latter, which ascends along the  tendo-achillis
and the posterior face of the gastrocnemius muscle, collecting
several small veins from the back of the leg in its course.  This
vein is superficial in its whole course, being placed immediate-
ly beneath the skin.  In  the  ham, it  goes  for a short distance
along the internal face of the popliteal nerve, and  then makes a
dip through  the adipose  matter there to empty into  the popli-
teal vein.
   It is  said, by Portal, that the branches  of this vein become
very apparent in persons who suffer from podagra, and from en-
largements of the lymphatic glands in the ham.   In such case,
their distention has been  relieved by the  application of leeches
along them.

   The Great Saphena  (Vena Saphena Magna, Interna)  is also
superficial, has its primitive roofs coming from the internal upper
part of the foot, and from the sole of the latter.  These branches
are assembled into  a trunk which passes upwards in front of
the internal  ankle, then ascends along the  internal face of the
leg, in a line corresponding with the posterior margin  of the
tibia.  The  great  saphena continues its  ascent over the inter-
nal condyle near its posterior part, and then mounts up  the  in-
ternal face of the thigh, in  a line corresponding nearly with the
internal margin of the sartorius muscle.   It finally terminates
in the femoral vein, about twelve or eighteen lines below Pou-
part's ligament, an opening being left in  the fascia  femoris  for
this purpose.
   In the whole of this course the great saphena is  situated  be- 
VEINS OF THE ABDOMEN.
263
tween the skin and the fascia of the lower extremity; it is, con-
sequently, so superficial, that in persons of moderate corpulency
it is very visible, and by slight  pressure above, along with the
erect position,  it  becomes so much swollen, that  it is  easily
opened with the lancet where it passes over the  internal  ankle.
It receives, in its ascent, small branches from the anterior and
posterior part of the leg, from the corresponding surfaces of the
thigh, and near its termination it gets a few of the external pu-
dendal veins.
  When the great and the small saphena veins are successfully
injected, their branches are seen  to form  a considerable num-
ber of anastomoses, which thereby produce a remarkable venous
net-work, just beneath the skin of the whole inferior extremity.


              SECT. IV.--VEINS OF THE ABDOMEN.

  The  External Iliac Vein, (Vena lliaca Externa,) being the
continuation of  the femoral vein,  passes into  the abdomen, un-
der Poupart's ligament, and in contact with the internal margin
of the external iliac artery.  It there  receives  the epigastric,
and the circumflex iliac veins, corresponding with the arteries of
the same name; it also receives a vein of some  size, which en-
ters by the  abdominal  canal in adhering to the spermatic  chord,
and which comes  from the coats of the testicle.*  It keeps  then
along the internal  side of the artery, somewhat behind it, at the
superior margin of the pelvis, and joins the hypogastric vein op-
posite to the sacro-iliac junction, and thereby forms the common
iliac vein.

   The  Hypogastric Vein (Vena Hypogastrica, lliaca Interna,)
comes from the inferior part of the pelvis in  front of the  sacro-
iliac junction, and in company with the hypogastric artery.  It
arises by branches corresponding with the distribution of the lat-
ter to the viscera  of the pelvis, and to its external parts; these
branches are so numerous at particular points,  and have  such
frequent anastomoses,  that they are often named Plexus.  Thus,
there is a hemorrhoidal plexus for the lower part of the rectum,
* H. Cloquet, Traite" D'Anat. 
264
CIRCULATORY SYSTEM.
avesical for the bladder, a sacral for the sacrum, a pudendal for
the parts of generation in the male, a vaginal for the vagina,
and a uterine  for the uterus of the female.
   The  Plexus Hemorrhoidalis, besides being  connected with
the hypogastric, also anastomoses with the branches of the vena
portarum.
   The Plexus Vesicalis is different in the  two sexes.  In man it
commences at the extremity of the  penis by several branches,
which unite into two trunks of considerable size, the Venae Dor-
sales Penis.*  The latter go along the upper face of the penis,
near or at its middle, to the symphysis of the pubes, continually
receiving in this course small trunks from the integuments of the
penis and from the scrotum.  They then get into the pelvis, be-
tween the root of the penis and the symphysis pubis, and conti-
nue horizontally backwards on the side of  the prostate gland, of
the vesiculae seminales, and  of the lower fundus of the bladder.
They receive  many branches from these parts, which, with the
frequency of the anastomoses about here, constitute the  vesical
plexus.  The latter, finally, discharges into  the lower part of the
hypogastric vein by two or  more branches.
   In the female the vesical plexus begins on the dorsum of the
clitoris, by several branches coming from it  and  from the
vulva;  they get into  the pelvis under the symphysis pubis,
and  on the sides  of the urethra and of the vagina, forming
upon the lower part of the bladder, and on  the side of the va-
gina, with  the assistance of  branches from these viscera,  a
remarkable plexus, which  also empties into the internal iliac
vein.
   The Plexus Sacralis consists in  an order of veins, anasto-
mosing  freely with each  other, and corresponding  with the
middle and the lateral  sacral veins.   They communicate with
the inferior end of the vertebral  sinuses through the anterior
sacral foramina; they also communicate with the hemorrhoi-
dal and with the vesical veins.  They terminate in the  venous
trunks, nearest the origin of the arteries  from  which they are
derived.
   The Plexus  Pudendalis is derived  from the branches of the

  ♦.They are frequently found to unite into a single trunk, called, in such case,
the Vena Magna Ipsius Penis. 
VENA CAVA INFERIOR.
265
internal pudic vein which go to the perineum, to the posterior
part of the scrotum,  and to the integuments of the under  part
of the penis.  The trunk formed  by the assembling of these
several  ramifications, follows the course of the  internal pudic
artery to which it belongs, and gets into the pelvis at the lower
part of the sciatic foramen, where it contributes to  the forma-
tion of the hypogastric vein.
  The Plexus Uterinus  consists in a  considerable number of
veins, which are distributed upon the surface, and in  the tex-
ture of the  uterus;  they are also  found in abundance in  the
broad  ligaments, where  they  anastomose with the  ovarian
veins.
  The Plexus Vaginalis  comes fronrthe anterior parts of the
organs of generation constituting  the^vulva, as the labia ma-
jora, minora, and so  on.   It also arises from the whole surface
of the vagina, surrounds it  completely, and anastomoses  with
the uterine veins.

  The Gluteal, the Obturator, and the Ilio-Lumbar Veins, also
contribute to the  Hypogastric; their description conforms so
nearly to that of the corresponding arteries, that it is unneces-
sary to detail it.

  The Primitive Iliac Vein, (Vena lliaca Primitiva,  Commu-
nis,) formed by the  junction of the External and of the Inter-
nal Iliacs, extends from the sacro-iliac  symphysis to the lower
margin of the fourth lumbar vertebra,  where it joins  the cor-
responding trunk of  the opposite side of the body, to form the
commencement  of the ascending  vena  cava.   In  this  course
the left one  passes obliquely across the body of the fifth lumbar
vertebra, and beneath the right primitive iliac artery.

  The Vena Cava Inferior is situated on the front of the spinal
column, to its right side, and extends from the  lower  part of
the  fourth lumbar vertebra; or, in other words, from the junc-
tion of the primitive iliac veins to the  under end of the right
auricle of the heart, into which it empties.  It  is  larger than
the Descending Cava.
  In its  ascent  it inclines very gradually to  the right  side of
     Vol. II.—24 
266
CIRCULATORY SYSTEM.
 the spine, so as to  reach the opening in the tendinous centre
 of the diaphragm,  through which it passes just  before it ter-
 minates in the auricle.   It is bounded on the  left side by the
 aorta; and above the latter it is in front of the  left  pillar of
 the diaphragm.   Its lower extremity is crossed in front by the
 root of the primitive iliac artery; it is also crossed in its ascent
 by the duodenum and the pancreas.  Its upper  extremity is be-
 hind the liver, and  frequently passes through the  substance of
 this viscus.
  It receives the middle sacral, the lumbar, the spermatic, the
 emulgent, the capsular,  the hepatic, and the phrenic veins.

  The Middle Sacral Vein (Vena Sacra Media) forms, as has
 been just mentioned in the account of the branches of the hy-
 pogastric vein, a part of the sacral plexus.  Its trunk follows
 the course of the middle sacral artery on the front of the sa-
 crum, and discharges into the commencement of the vena cava,
 in the fork  formed by the junction-of the primitive  iliacs.

  The Lumbar Veins (Vence Lumbales)  correspond with the
 lumbar arteries, and are commonly four or five in number on
 each side.   Their primitive  roots  anastomose with the epigas-
 tric, the last intercostal,  and the  circumflex iliac veins; the
 dorsal  branches of  them  also anastomose with the  vertebral
 sinuses, through  the intervertebral foramina.   Their  trunks
pass along with the arteries, between the bodies of the vertebrae
and the psoas magnus muscle, or through the fasciculi of the
latter:  those on the  left  side  pass  behind the aorta, in order to
reach the vena cava, and are, consequently, longer than such as
are on the right.

  The Spermatic Veins (Vence Spermaticce.)   The  right one
extends from the testicle to the ascending cava, just below the
emulgent veins;  while the one on the left  empties  into the left
emulgent vein.  They are larger  than the corresponding arte-
ries, and present some peculiarities in the two sexes.
  In the male, the extremities of these veins begin in the testi-
cle, and issue from it through the tunica albuginea; some of them
also arise from the epididymis.  They anastomose  with the su- 
VEINS OF THE ABDOMEN.
267
perficial veins of the penis and of the scrotum, and disengaging
themselves from the tunica vaginalis, at its back part, are assem-
bled into four or five anastomosing trunks;  which envelop the
vas deferens and the spermatic artery, and compose a principal
part of the bulk of the chord.  Having passed through the ab-
dominal canal, they are reduced  on each  side to one trunk,
which creeps along the spermatic artery on  the front of the
psoas magnus muscle, and in company with  the ureter.  Some-
what below the kidney, the spermatic  vein is again resolved
into a sort of plexus, having frequent additions from the veins,
in the adipose substance of the kidney,  and  also some from the
branches  of  the vena portarum  in the mesentery, and in the
mesocolon.   It then is reduced once more  into  a single trunk,
which terminates as mentioned.   The  term Corpus  Pampini-
forme (vine-like) is, by some anatomists,  limited to the  last
plexus formed by each spermatic  vein, but  it is  also frequently
extended  to both.*
   In the  female, the spermatic vein is not  so large  as in the
male; it  comes from  the  ovarium and  from the  side of the
uterus, and is joined by some small branches from the round
ligament of the uterus, and from the Fallopian tube.   Passing
outwardly between the laminae of the  broad ligament of the
uterus, it crosses the external iliac artery, and  in the subsequent
part of its course is disposed of as in the  male.

   The Emulgent Veins {Vence Ernulgentes, Renales)  are com-
monly two in number, one on each side, and extend horizon-
tally from the  fissure of the kidneys  to the ascending cava.
They are of a considerable size,  and  owing  to the position of
the vena  cava, the left  is much  longer than  the right,  and
crosses in front of the aorta.  They open  on their respective
sides of the  cava  opposite to each other.   The branches of
which the emulgent vein  is composed,  coming from  the rami-
fications of the corresponding artery in  the  kidney, assemble
into  the  single trunk near  the  fissure  of  the kidney;   this
trunk  is joined by  some small veins  from the adjacent   adi-
pose  matter  and from the capsulae renales, and  on the left
side, as mentioned,  it is also joined by the spermatic vein.
* H. Cloquet, Trait. D'Anat. 
268
CIRCULATORY SYSTEM.
  The Capsular Veins (Vence Capsulares)  arise from the arte-
ries spent upon the  capsulae renales;  and are two in number,
one on each side.  That on the right discharges into the vena
cava, while the one on the left empties  into the left emulgent
most  frequently.

  The Hepatic Veins (Venae Hepaticce) take their rise in the
liver, and collect into three principal trunks, which converging
towards  the  ascending cava, discharge  themselves into  it,
where it  adheres  to the posterior  margin of the liver, imme-
diately below the diaphragm.   Two of these  trunks come from
the  right  lobe, and  one  from the left, moreover, there are
several small  hepatic veins which" discharge  themselves into
the cava, and come principally from the Lobulus Spigelii.

  The Inferior Phrenic Veins (Venae  Pkrenicas Inferiores)
come  from the diaphragm, from the corresponding arteries.
They are  two  in number, and discharge into the  ascending
cava just above the hepatic veins.

              SECT. V.--OF THE VENA PORTARUM.

  The. Vena Portarum  is derived from the viscera of the abdo-
men, and presents the singularity of a vein ramifying through
a gland, the (liver,) before its blood is returned to the general
circulation. - The arteries from  which  it draws  its supply of
blood are the superior  and the inferior  mesenteric, and the
cceliac with the exception of its hepatic, branch.  The  viscera
of the abdomen, which contribute to it are the spleen, the gall-
bladder, the pancreas, the  stomach, the small and large intes-
tines,  and the large and  the small omentum.
  a. The Splenic Vein (Vena Splenica) is formed by  several
branches, which coming out distinctly from  the fissure  of the
spleen, unite  after  a short course  into  a  single trunk.  This
trunk runs in company with the splenic  artery below it, along
the superior margin of the pancreas, it is not quite so tortuous
as the artery itself, and proceeding from left to right, is joined
to the superior mesenteric vein in  front of the vertebral co-
lumn. 
VENA PORTARUiM.
269
   In this course, the splenic  receives the small veins,* (Venae
 Breves,) corresponding with the vasa brevia of the great end of
 the stomach, and then, successively, several branches from the
 pancreas.  It likewise receives the gastric, or the superior co-
 ronary vein of the stomach, the right gastro-epiploic, and the
 left gastro-epiploic of the same viscus, all of which correspond
 with the arteries distributed to the latter.
   b.  The Inferior Mesenteric Vein (Vena Meseraica Inferior)
 corresponds with the  inferior  mesenteric  artery, and, conse-
 quently, derives its primitive  branches from the rectum by the
 upper hemorrhoidal veins, which anastomose with the lower;
 from the sigmoid flexure  of  the colon, and  from the left de-
 scending portion of  the latter.  The trunk formed by these
 branches, ascends behind the peritoneum, between  the left ureter
 and the  aorta; and going up behind the pancreas,  is discharged
 into the  splenic vein an inch or two from its termination.   But,
 like the  veins belonging to the  lesser  curvature, and the right
 side of the stomach, it sometimes empties directly into the vena
 portarum, or into the  upper end of the superior mesenteric.
   c. The Superior Mesenteric Vein (Vena Meseraica Superior)
 is the largest of the trunks which contribute to form the vena
 portarum.  It is derived from the ramifications of the superior
 mesenteric artery upon the small intestines, the ileo-colic valve,
 the right ascending and the  transverse  colon.   Its branches
 constitute in the mesentery and the mesocolon a vascular in-
 tertexture, forming arches and meshes adhering to the corre-
 sponding ones of the arteries.   In the transverse mesocolon, it,
 like the  artery, anastomoses with the  inferior mesenteric vein.
 Its trunk being formed by the union of these several  branches,
 ascends  the  mesentery, and  goes  in front  of the duodenum,
 where the latter crosses the spine; immediately afterwards it
 gets behind  the pancreas, and  near its right end  is  joined by the
 splenic vein.  It  here, also, receives small  branches from the
 duodenum, from the pylorus, and from the gall-bladder.

   The trunk of  the Vena Portarum being formed behind the

  * M. Bauer discovered, in 1824, valves in  these vessels, contrary to the gene.
ral analogy of  the system of the Vena Portarum.  His observations have been
confirmed by H. Cloquet
                            24* 
270
CIRCULATORY SYSTEM.
pancreas by the union of the superior mesenteric with the sple-
nic vein, extends from this point to the transverse fissure of the
liver, and is about four inches in length.   It  ascends obliquely
from left to right, behind the second curvature of the duodenum,
being bounded on  the right side by the  biliary ducts, and  on
the  left  by the hepatic  artery, where it is  surrounded  by a
great many nervous filaments and lymphatic vessels, with  all
of  which it is united  by a common envelope of cellular sub-
stance, and  of peritoneum,  called  the  capsule  of Glisson.
Having reached the transverse  fissure of the  liver, it divides
into two branches, which are each at a right angle to it, but in
line with one another: they constitute the Sinus Portarum, of
which the right branch being spent  upon the great lobe, and
the left upon the small lobe of the liver, are ramified almost to
infinity through the structure of the latter.   The  terminating
branches of the vena portarum empty into the  venae hepaticae.

  Several cases are recorded in the annals of anatomy in which
the vena portarum, instead of going into the  liver, discharged
immediately into the ascending cava.*  In such instances the
hepatic artery is much larger than usual.  According to J. F.
Meckel, notwithstanding they are  anomalies, yet, as in most
other cases of deviation from the general type of the human fa-
mily, a striking analogy may be found between them and what
occurs in some of the lower orders of animals.  Here the ana-
logy exists with the invertebrated animals.
                    CHAPTER  IV.

OF THE PECULIARITIES IN THE CIRCULATORY SYSTEM OF THE
                          FOETUS.

  Owing to the want of respiration in the foetus, its circulation
is conducted in a manner very different from that of the adult.
Moreover,  its  parasitical life requires an  alliance,  through  the

 * Lieutaud, Hist. Anat. Med. Hubcr, Obs. Anat.  p. 34.  Abernethy, Ph. Tr.
1793, part i.  Lawrence, Med. Ch. Tran9. vol. v. 
PECULIARITIES OF THE FffiTUS.
271
organs of circulation, with the mother.  Its peculiarities, there-
fore, may be studied under two heads: those which arise from
the want of respiration, and those which are required for its
nourishment.   The  peculiarities of the first order are situated
in the thorax, and those of the  second in the abdomen.


SECT. I.--OF THE PECULIARITIES OF THE FC3TUS, ARISING FROM THE
                    WANT OF RESPIRATION.

   The Heart, at a very short period after eonception, so  early
as about the end of the first month, is sufficiently developed to
be in a  state of great activity.   The first indication of its exist-
ence, and, indeed, of the life of the new animal, is a small tre-
mulous  point, called the Punctum Saliens, from  its incessant
motion.   The  muscular structure of it is soon evolved, and
in a few weeks becomes very manifest.   At the earliest visible
period of the heart in the incubated egg, which affords a  satis-
factory analogy, it consists of  two vesicles united by a canal,
(Canalis Auricularis of Haller.)   One of the vesicles is the right
auricle; the other is the left ventricle, and is probably the first
to pulsate.  The aorta is also visible, as well  as the venae cavae.
The circulation, at this period, is very simple: the blood, start-
ing from the left ventricle, is propelled into the aorta;  it is col-
lected from the ramifications of the last into the two venae cavae,
and thereby brought to the right auricle; it is then propelled by
the right auricle  through the  canalis auricularis into  the left
ventricle, whereby its  round  is completed,  and it then starts
again.  This is the most simple kind of circulation, and is found,
in fact, during the whole lives of such animals as do not breathe
by lungs; for example, fish.  As the gills in them take the place
of lungs, a branch from the aorta, spent upon the gills, is suffi-
cient for their purposes of respiration.
  The terms right auricle and left ventricle have been used, be-
cause the cavities alluded to perform the  functions of the  adult
state; but in the progress of the development of ihe heart, a par-
tition begins to show itself which ultimately divides each of them
into two distinct compartments, whereby  we have a right auri-
cle and  a  left one, a left ventricle and a  right one.  And the
canalis auricularis is reduced from a canal into a  short orifice, 
 272                 CIRCULATORY SYSTEM.

 called Ostium Venosum, communicating from the auricles to
 the ventricles, and which is afterwards divided into two, one
 for either side of the heart.   The partition between the ventri-
 cles is completed about the end of the second month of gestation,
 at a period when  the aorta, from having been simple original-
 ly, is converted into two canals, one of which becomes the pul-
 monary artery.  The partition between the auricles is not com-
 pleted till birth.  In cases of monstrosity, it is interesting to see
 how much the heart, at the end of uterine  life, has still  pre-
 served this original type of  simplicity.  I have lately dissected
 a double foetus, where, from the parasitical  character  of one,
 no effort had been made for  the development of the lungs of the
 latter.  The consequence of which  was, the parasite's  heart
 consisted only of the right auricle and of the left ventricle, and
 the pulmonary artery had not been formed at all, there being but
 the single tube, the aorta, which led from the left ventricle, and
 had a  sort of arrangement  in its branches depending upon the
 tendency to form pulmonary arteries.*
  At birth,  the auricular  septum has advanced so far that the
 communication between  the two cavities is kept up only by a
 deficiency, called the Foramen Ovale.  This  foramen, marked
 by a depression on the right side, admits a small  quill, when
 conducted obliquely through it, and is protected on the left side
by a valve, the edge of which is upwards, and which, when ap-
plied, is just large enough  to cover the whole foramen.  The
moment  that  the  blood  ceases  to  pass  through the foramen
ovale,  which occurs at the  first act of inspiration, the valve is
applied,  and the  aperture  grows  up by the adhesion of its
edge.  The mechanism of  this process is sufficiently  simple.
So long as the principal current of the blood was into the right
auricle, the valve was  pushed off from the side of the septum;
but as breathing establishes, through the lungs, pulmonary veins,
and  left  auricle, a current  of circulation equivalent, both in
quantity  and force,  to that through  the two venae cavae and
right auricle, a perfect equilibrium between the auricles is esta7
blished, and  the valve retains  its  place against the septum.
Notwithstanding the incessant action of the auricles, during all

 * For a detail of this case, S2c North American Medical and Surgical Journal,
Philad. Oct 1826. 
PECULIARITIES OF THE FffiTUS.
273
 the subsequent periods of life, this equilibrium, in  the force and
 time  of their contraction,  remains uniform:  a  circumstance
 proved, conclusively, by  the  health  and strength of adults in
 whom the valve has never adhered to the day of their death;
 an observation made by many anatomists, and of  which I have
 witnessed several examples.   In one of them  I passed two fin-
 gers readily from one auricle  into the other, owing  to the un-
 usual size of the aperture.
   The  valve which closes the  foramen ovale is,  first  of all,
 Scarcely perceptible ; but as the foetus advances in age,  it also
 advances in size, and is, indeed, large enough  to close the fora-
 men  some weeks before birth.   It is formed from the  lining
 membrane of  the two  auricles,  with  some intermediate sub-
 stance.

   The Valve of Eustachius, which exists also in the adult  heart,
 is placed at the antp.rior semi-circumference of the orifice of
 the ascending vena cava in  the right auricle, one of its ends ad-
 hering to the anterior margin of the foramen ovale. This  valve,
 contrary to the one in the foramen ovale, is larger in proportion
 as the foetus is  younger, and, when first observed, covers the
 whole orifice of  the vena cava ascendens; its opening, however,
 is in the direction of the current of blood in the latter.  It also is
 formed by a duplicature of the lining membrane of the auricle;
 and, from its disposition, determines the blood  of the ascending
 cava  to  flow through the foramen ovale into  the left  auricle,
 either wholly or in part, according to the  period of gestation.
 Its obliquity also gives a direction to  the blood of the descend-
 ing cava, into the right ventricle from the right auricle.   These
 uses of the Eustachian valve were pointed out by the celebrated
 Sabatier:* their  value will be illustrated hereafter.

   The ventricles of the  Heart, at birth, have  the same  struc-
 ture and internal arrangement as  afterwards; they are remark-
 ble, however, for being of equal thickness, or nearly so, an ob-
servation  of  Mr.  John  Hunter.t   This fact is connected  with
 the circumstance of  their both contributing to the aortic cir-
 culation  till respiration begins, owing to the pulmonary artery
* Traits d'Anat. vol. ji. p. 296.
f Animal CEconomy, 
274
CIRCULATORY SYSTEM.
entering,  during fcetal life, by  its largest branch, into the
aorta.

  The Ductus Arteriosus  constitutes this branch of the pulmo-
nary artery, and is, in fact, the continuation of the trunk of the
latter into  the aorta, immediately behind the origin  of the left
subclavian artery.   The  right and  the left pulmonary  artery
at this  period, are but inconsiderable trunks, incapable by any
means of carrying off all  the blood of  the  right ventricle; the
greater part  of  it, therefore, is conveyed by the duetus arterio-
sus into  the  descending aorta.  As the contraction of the ven-
tricles, like that  of the auricles, is synchronous, it is evident that
the column of blood in the  descending aorta, is acted upon by
both ventricles at the same moment.
  The ductus arteriosus preserves the principle of a single cir-
culation in the fcetus, which was first of all manifested  by the
two ventricles,  constituting but one cavity, and by the aorta
and pulmonary  artery being but one trunk.   At the first act of
inspiration the lungs, which were before solid, and the thorax,
which was compressed, are greatly augmented in volume by the
introduction of air.  The  dilatation of the thorax, besides intro-
ducing air through the trachea, causes an increased flow of blood
through  the right and left pulmonary arteries, in order to fill the
vacuum  in the lungs.  The pulmonary arteries become  in that
way permanently dilated, and the  circulation  is finally drawn
off entirely from the ductus arteriosus, though this takes several
weeks or months before it  is completely accomplished.  The duc-
tus arteriosus in this time is continually contracting, and is at
length converted into a ligamentous chord, like  other arteries,
whose circulation has been  arrested.

  These are the several peculiarities which  distinguish the fcetal
circulation, owing to the privation of respiration; and it is clear,
that the collective result is that  of a circulation quite as simple
as if the heart consisted of but two cavities; while, at the same
time, it keeps this organ in  a  state of preparation for carrying
on two distinct circulations, one pulmonary  and the other aortic,
from the moment  that respiration  begins: so that  the  whole
mass of blood is, in  subsequent life, brought successively under 
PECULIARITIES OF THE FffiTUS.
275
the influence  of respiration,  by having  to  pass unavoidably
through the lungs.


 SECT.  II.--OF THE  PECULIARITIES OF THE CIRCULATION OF THE
           FffiTUS CONNECTED WITH ITS NOURISHMENT.

   The Umbilical Vein, one of the constituents of the umbilical
chord, brings the blood from the placenta to the fcetus.  This
vessel  is from three to four lines in diameter, and enters at  the
navel; thence it goes along the loose margin of the suspensory
ligament of the  liver, and traverses the anterior half of the um-
bilical fissure, to terminate in the left branch of the sinus of the
vena portarum.  In this  course  through the liver, the umbilical
vein sends off to the right and the left lobe several small branches.
As the intestinal circulation  of  the fcetus is too small to send
much blood through the  vena portarum, it would be sufficiently
correct to consider the sinus venae portarum as the bifurcation
of the umbilical vein; but, as this might introduce a  confusion
into the description, it will be better to retain the adult nomen-
clature.

   The Ductus Venosus  is a  vein which occupies the posterior
half of the umbilical fissure, and is about a line and  a half in
diameter.  It arises from the left branch of the sinus portarum,
opposite to the place where the  umbilical  vein entered or termi-
nated, and is consequently in the same line with the latter.  Tra-
versing the posterior part of the umbilical fissure, it terminates
in the  left vena  cava  hepatica, as this vein is about joining the
ascending cava, just below the tendinous centre of thediaphragm.
Through this  route much of the blood of the umbilical vein is
carried directly to the right auricle of the heart, and then passed
through the foramen ovale into the left auricle by the mechanism
of the Eustachian valve.

   From  these considerations, it is evident  that the umbilical
vein really performs the  office of a vein till it reaches the liver,
but that there much  of  its blood is spent  through  the portal
circulation,  upon the structure of this viscus, and that what re-
mains  is carried through the ductus venosus to the heart.  Like 
276
CIRCULATORY SYSTEM.
other veins, it is furnished with valves, of which there are two:
one at its termination  in  the sinus portarum, and the other at
the cardiac extremity of the ductus venosus.*  The establish-
ment of respiration, by putting the circulation into other chan-
nels, likewise causes its obliteration and final conversion into a
ligamentous  chord.  The valve,  at  the  sinus  portarum, pre-
vents the blood from  taking a retrograde course, and thereby
keeping the umbilical vein open;  the valve of the ductus veno-
sus has the same effect upon the duct to which it belongs, and
is aided by the current of blood in the left branch of the  sinus
portarum, setting across the mouth of the ductus venosus in-
stead of plunging  into it  from the umbilical vein, as in  fcetal
life.
  It is worthy of remark, that the left branch of the sinus por-
tarum  is bounded, on  its right extremity, by the  end of the
vena portarum, and receives, about  its middle,  the umbilical
vein.   In the space, then, between the umbilical vein and  the
portal, the circulation, from the predominance  of umbilical
blood in foetal life, is conducted from left to right, but afterwards
from right to left, as  the portal circulation is established and
the other is arrested.

  The Umbilical  Arteries  discharge  the  important office  of
conducting the effete blood of the fcetus to  the placenta.  They
are the continuations of the  internal iliacs, and are two in num-
ber, one on either side; they conduct off so much of the blood
of the  primitive  iliacs, as  to leave the external iliacs of a very
small size.  During the early months  of uterine life, they are
rather, indeed, the continued trunks of the primitive iliacs, the
branches from the latter being then so little developed as to ap-
pear quite subordinate to the  chief  function of carrying the
blood out of the fcetus  to the placenta.  But as the inferior ex-
tremities and the  buttocks  grow, these subordinate branches
are more and more evolved.
  At birth, the umbilical arteries, after dipping very superficially
into the pelvis, rise up  at the sides of the bladder and converge
towards the navel.  They emerge at the latter, cling together
and traverse the umbilical chord by twisting spirally around the
* Bichat, Anat. Descrip. vol. v. p. 419. 
PECULIARITIES OF THE F03TUS.               277
umbilical vein, like two small strings wound in this way upon a
larger one.  Their diameter is from a line to a line and a half.
They anastomose as they join the placenta, but  not previously.
   Like the  circulation  between  arteries  and  veins in other
parts of the body, the capillaries of the umbilical arteries termi-
nate in those of the umbilical vein in the  placenta.  From the
observations of Wrisberg, Osiander, and the highly distinguished
Professor Chapman of the University of Pennsylvania, it seems
that there is no direct vascular communication between the mo-
ther and the fcetus.
   This opinion  is founded upon the leading facts, that the finest
injections do not pass from one to the other; that foetuses, after
the death of the mother from haemorrhage, still live and retain
their usual quantity of blood; that if the fcetus be expelled entire
with the placenta,  and membranes  unhurt, the circulation still
continues.  One example of which was  witnessed  nine minutes
by Wrisberg;* another fifteen  by  Osiander;f some from ten to
twenty minutes by Professor Chapman;J another for an  hour
by Professor Channing of Boston, and Dr. Selby  of Tennessee,§
where a bath of tepid water was  used to resuscitate the fcetus.
Also, from the observations of Breschet, it seems  that the glo-
bules of the blood of the fcetus, when inspected by the micro-
scope, are different in appearance from those of  the mother.||
   Mascagni says that he has  made several most minute injec-
tions of the pregnant  uterus, so as  to- cover with  small vessels
its whole  internal surface, and  to return the injection by the ute-
rine veins: and"  yet he has never succeeded in injecting, in that
way, the  secundines.il
   I  have,  myself, repeatedly tried  by minute injection to pass
articles from the fcetal  into the maternal vessels, and the re-
verse, but always without success; in  two instances, the experi-
ment was upon  human subjects, and, in the others, on the  cow.
In one of the latter, I perceived that some of the  injecting  mat-
ter thrown into the foetal  vessels had got into the uterine veins;
but as  the observation was in  opposition  to all  my other, and

•  Meckel, Man. D'Anat. vol. iii. p. 163.         f Id.
$  Chapman's Med. and Phys. Journal, vol. i. p. 6.  § Id.
U  Am. Med. Jour. vol. i. p. 193.                1 Prodromo, vol. i. p. 127.
  Vol. II.—25 
278
CIRCULATORY SYSTEM.
solitary, I have felt no disposition to array it against them, at
least, until farther and more decided experience.  My second ex-
periment on the human subject was  made in April, 1833, under
the following circumstances: A white female, aged 24, died at
the Alms  House, suddenly, and in the ninth month of pregnan-
cy, the fcetus was still in utero, but  the membranes were rup-
tured.  In the presence of several of the physcians and students,
and with  the assistance of my young friend, Dr.  Goddard, to
whose suggestions and manipulations I am indebted for the che-
mical compounds resorted to, I injected through the aorta one
gallon of the saturated solution of Prussiate of potash, and fol-
lowed it with  an equal  quantity of a saturated solution of sul-
phate of iron.   The injection penetrated very minutely, as might
be expected, and the precipitate of Prussian blue coloured deep-
ly many parts of the skin.   On dissecting the uterus, the uterine
arteries were found well injected, but the injection did not reach
the umbilical vein or arteries, as was proved both by simple in-
spection and by chemical test.
  Having cut out the uterus and taken it to the University, the
experiment was continued  the  next day in  the  presence of a
large concourse of students and several physicians.   The um-
bilical vessels were first of all injected with a saturated solution
of bichromate  of potash, and then with a saturated solution of
sugar of lead, the result was a strong, yellow precipitate, the
bichromate of lead. The  injection  passed  reciprocally from
the  arteries into the vein,  or from the vein  into the arteries,
conformably to  the direction in which it was thrown for the
time.   The sinuses of the uterus were then injected with  similar
materials  to those of the uterine arteries; to wit, a solution of
Prussiate of potash, followed by one of sulphate of iron.
  The umbilical vessels were then all filled with liquid plaster of
Paris coloured yellow ; and the  uterine sinuses with liquid plas-
ter of Paris coloured blue, of which they readily received eigh-
teen ounces.   A short time having been allowed for the setting
of the injection, I cut into the substance of the uterus and of the
placenta.  No yellow injection  was found in  the vessels of the
uterus, nor was there any blue injection found in the umbilical
vessels of the placenta; there was, therefore, a deficiency of evi-
dence of direct vascular communication between the fcetus and 
PECULIARITIES OF THE F03TUS.
279
the mother. The placenta was infiltrated with Prussiate of iron,
and considerable quantities of blue plaster were found in the ca-
vity of the uterus.
   In the progress of the injection with the Prussiate of iron, into
the uterine sinuses, the membranes were raised from the  uterus
in vesications.
   The parts having been distended and put aside to dry, at the
end of a fortnight they were examined again by incisions, and
the same evidence of the want of direct vascular communication
was renewed.   But the placenta was found to be infiltrated ac-
cording to certain rules seeming to depend  on its organization.
The blue colouring  matter on the part of  the uterus, and the
yellow on the part of the fcetus, determined in it two parts, one
uterine and the other fcetal, closely and alternately interlocked,
like a dove-tailing: the uterine processes  passed  to within a
short distance of the free surface-of the placenta, while the fcetal
processes went  almost to the base of the placenta.   The con-
fines of the two colours were defined well by this abrupt ter-
mination, the borders of these dove-tails.  Tho appearance
would, perhaps,  be better designated by the terms uterine lobes,
and fcetal lobes, alternately penetrating, so as to constitute the
whole mass of the placenta.  No distinct vessel of a blue co-
lour could, however, be seen in the uterine lobes;  but  a  few
very  sparse  yellow ones were visible.  On raising up these
uterine divisions, the  orifices  of the uterine sinuses  were seen
at their base.
   The inference from this experiment is, that though there is no
direct connexion of blood vessels between the  mother and the
fcetus, yet there  is a part of the placenta which seems to  hold a
special connexion with the uterine sinuses, and  which may pos-
sibly, therefore, by interstitial  circulation, establish a connexion
with the fcetus.   The facts are at any rate' presented as they
occurred.
   The effete blood of the umbilical arteries becomes regenerated
in the placenta,  assumes a brighter hue, and is returned  to the
fcetus by the umbilical vein.   According to  the theory of Saba-
tier concerning  the use  of the Eustachian  valve, if  the latter
did not exist, the fresh blood brought  to the heart by the
ductus venosus,  instead of being diverted into the left auricle
through the foramen  ovale, would  be received by  the  right 
280
CIRCULATORY SYSTEM.
auricle, and transmitted, either wholly or in a great degree, into
the right ventricle.  It would then be passed from the  latter
through the pulmonary artery and ductus arteriosus into the de-
scending aorta, so that no part of the system, above the junction
of the duct with the aorta, could receive the benefit of it:  this
would leave  the head  and upper  extremities  unsupplied with
fresh  blood.  Moreover, much of the latter would be fruitlessly
introduced, for it would depart almost immediately through the
umbilical arteries.  But the Eustachian valve determining the
flow of blood of the ascending cava into the left auricle, its pas-
sage into the left ventricle is a matter of course: thence it be-
gins the aortic circulation fairly, so that every part of the sys-
tem participates in its benefits.
  The  celebrated  Wistar* has also happily suggested, that
without this arrangement the blood of the coronary arteries of
the heart itself, the purity of which is so essential to the vigour
of circulation, would otherwise have been effete, and, conse-
quently, unfit for its object  of refreshing the heart.

  The umbilical arteries become the round ligaments of the
bladder, after the circulation through  them has ceased, with
the exception of their pelvic extremities, which subsequently
constitute the trunks of the Internal Iliac Arteries,
                    CHAPTER  V.


  OF THE GENERAL ANATOMY OF THE ABSORBENT SYSTEM.

  The absorbent system is one of the most interesting of those
which compose the human body, both on account of its very
general diffusion, and of the office of interstitial absorption that
it incessantly carries on, thereby removing the effete parts of
the  body a^i.d making room for the deposite of new ones.  It is

              f Sysiera(o^ Anat. vol. ii. p. 76, 3d edition. 
ANATOMY OF THE ABSORBENT SYSTEM.
281
also called the lymphatic system, owing to the transparent co-
lour of the fluid which it conducts.

  With the exception of an imperfect observation of some  of
these vessels in the mesentery of  a goat, by Herophilus  and
Erasistratus, 280 years before Christ, during  the reigns  of the
Ptolemies in Egypt, what is known of them is entirely a modern
acquisition in anatomy.  In  1564, Eustachius  discovered the
thoracic duct of a  horse, which in  the ignorance of its use, he
called vena alba thoracis.  This fact remained insulated  and
almost forgotten for  seventy years.   In 1622,  Asellius  disco-
vered the absorbents of the mesentery, and in  the discussions
consequent thereto, the original observation of Herophilus and
Erasistratus was raised from  an oblivion of nineteen centuries,
to be again brought to  light  and admired.   Asellius seems  to
have understood that the absorbents of the  mesentery collect
the chyle from the intestines,  but his knowledge ceased there,
for he thought that they discharged into the vena portarum.*
In 1634, Weslingius saw the thoracic duct again; and in 1649,
ascertained that the chyliferous vessels  of Asellius  terminated
in it.  In 1650, Olaus Rudbeck, a young man pursuing his ana-
tomical studies  in  Leyden, saw  first the lymphatic vessels  of
the liver, and in a few months afterwards injected similar ones
in the loins, in the  thorax, in  the groins, and in  the arm-pits.
Thomas Bartholine, a teacher of great reputation in those days,
in a dissertation, dated in 1652, claimed for himself the priority
of these observations, and from the obscurity of Rudbeck, en-
joyed  for some time the merit of them.  In  1654, Rudbeck
published and set  forth his own pretensions  with such  force,
that he finally triumphed over his antagonist, but not until the
whole world of anatomy had been set in commotion ; one party
being for the professor, and the other for the  pupil;  and many
bloody strifes having arisen between the students  of the re-
spective sides.   In  1653, Jolyff, a celebrated anatomist, of Lon-
don, proclaimed his own rights to this warmly contested ho-
nour;  but the period being rather late, his name is scarcely

  * It is somewhat remarkable, that the celebrated Harvey, who had himself so
much to complain of, in the obstinacy with which his cotemporaries adhered to
ancient errors, for thirty years resisted the discovery of Asellius, and died, final-
ly, protesting against it.
                            <*0 
282
CIRCULATORY SYSTEM.
associated with t^ie history of these feuds.   Almost a century
then passed  before there were many important additions to the
knowledge of those times.   After which  great contributions
were made  by  Dr. A.  Munro,*  Dr. W.  Hunter,f Hewson.J
Cruikshank,§ but chiefly by the celebrated Mascagni,f|  who,
having imagined finely pointed instruments of glass for exe-
cuting his injections  of these  vessels,  succeeded in demon-
strating them in almost every part of the body, excepting the
spinal marrow, the brain, the ball of the eye, and the placenta.
In some  of these parts, however, he  says he has seen them,
and he speaks confidently of their existence, without exception,
every where, even in the enamel of the teeth. Tl

  The Lymphatic Vessels  are small, pellucid, transparent cy-
lindrical  tubes, generally of  about a line  or less in diameter,
whose trunks have  been traced to all the external and internal
surfaces  of  the body, and to the depth of  all the organs, with
the exceptions stated.  It is only very lately, however, that their
existence on the external surface of the skin has been put be-
yond doubt, by the observations and injections of M. Lauth.**
Their origin is so attenuated, that anatomists have come, to no
satisfactory conclusion in regard to its manner.   The earlier
cultivators of this branch of study, not knowing their absorbent
properties, conceived them to be continuations of the arteries
applied to the reconducting of the serous part of the blood  to
the heart; and considered the opinion  substantiated by  the cir-
cumstance of their being occasionally filled by fine  injections
thrown into the arteries.  More improved views of their uses
caused the abandonment of  this theory, and the substitution of
their absorbing  powers; in which case the minds of anatomists
became  divided between the ampulla-like mouth, or wide patu-
lous origin  of Lieberkuhn,  and the small  orifices  of Hewson.
It is, perhaps, not possible to solve the question in regard to the

  * De Venis Lymph. Valv. Berlin,  1757-70.
  t Med. Comment. London, 1762-77.
  X Experimental Inquiries, London, 1774-77.
  § Anat.  of the Lymphatics, London, 1774-90.
  (1 Vasor. Lymph. Corp. Hum. Historia et Ichnographia, Siennc, 1787.
  ^[ Prodromo della Grande Anatomia, vol. i. p. t.
  ** Essai sur les Vaisscaux Lymph. Strasburg, 1824. 
              ANATOMY OF THE ABSORBENT SYSTEM*           283

mode of origin of the lymphatics, at least* in most parts of the"
body.   Meckel, about the middle of the last century, asserted
their continuity with the veins.  Mr. Ribes has seen matter in-
jected into the  vena portarum find its way into the lymphatics
of the-liver.
  On this subject, M. Chaussier says,* that, ignorant of the mari-
ner in which the arteries, veins, nerves, and lymphatics, arrange
themselves collectively into a glandular structure, or, in other
words, into a capillary system, we  cannot avoid ignorance of
the part acted by the lymphatics alone; we only know that the
minute lymphatics form a  portion of the elements of each viscus
and structure of the body, and that they only become visible in
becoming larger trunks.
   The absorbents,  in proceeding from their origins, in general
become larger and less numerous, and form frequent anastomoses
withone another. The proportionate increaseof magnitude from
the successive junction of trunks is, however, by no means equal
to what occurs in the veins.   The larger superficial absorbent
trunks of the extremities  have not so much  disposition to run
into one another, whence they retain a size almost uniform from
one end of the limb to the  other.   When fully distended, the ap-
pearance of absorbents is not regularly cylindrical, but knotted,
owing to the  frequent valvular  interruptions to their cavities.
The absorbents, from all  parts of the body, are finally united
into two trunks:  one on the left, and the other on the right side
of the trunk of the body, and which discharge their contents into
the venous system, each on its respective side, at the junction of
the internal jugular and subclavian vein. The trunk on the right
side receives the lymphatics of  the right side of the head  and
neck,  of the right lung, and right superior extremity; while the
trunk on the left, called the thoracic duct, receives all the chyli-
ferous  vessels and the lymphatics of the remaining part of the
body.  It would appear, from the observations of the younger
Lauth,t that there are also other terminations of the lymphatics
 in the veins; to wit, such as in the yet capillary state end in the
veins of the minute structure of organs, and such as empty into
them in the interior of the  lymphatic glands.   Previously to
Lauth, this sentiment of communication  with  the veins was
* Diet des Sciences Med. Art. Lymphatiques.           t Loc. cit. 
284                 CIRCULATORY SYSTEM.
strongly advocated by several anatomists and physiologists, for
the following reasons: 1. That  the known  roots of the lym-
phatic system have an area much superior to that of the trunks
in which they terminate.   2. That substances introduced into
certain lymphatics by absorption or injection, have been found
in the contiguous veins.  3.  That a ligature upon the thoracic
duct produced death  only after ten or fifteen days, and then the
articles which had been absorbed by the intestines, were found
in the blood.  4.  And that injections had proved this commu-
nication.
   Notwithstanding the well known fact of injections, under cer-
tain circumstances, passing from the arteries  into the lympha-
tics, some anatomists of modern date have  hesitated in admit-
ting a direct communication.  M. Meckel has, indeed, rejected
the notion entirely, on the ground that the fluid contained in the
trunks of the absorbents is always the same as one  finds at their
commencement.  For example, the lymphatics coming from the
liver contain a fluid like bile; those which come from the mammae
contain a fluid like milk; those which come from parts suffering
from  an extravasation of blood contain a sanguineous fluid; the
bronchial glands are  coloured by the black pigment brought to
them  from the lungs; poisonous matter, as that of the small-pox
or venereal,  irritates and inflames the lymphatics that lie  in the
course of its introduction into the  system.  For these reasons it
would appear to him, that the arteries do not continue themselves
into the lymphatics as they do into the veins.  The observations
of M. Lauth seem to have proved  the point, that  some of the
lymphatics take their origin from the internal surface of the ar-
teries; and  it may be through them that injections  have been
forced from  one system into the other.   In the case of the liver
of a child, I  have injected its  absorbents very successfully from
the arteries.
   The coats of the lymphatics generally are too thin  and trans-
parent for an investigation of their structure; but as those of the
thoracic duct are sufficiently large for the purpose, one  may
estimate the structure of  other trunks by it.  It is thus ascer-
tained that they consist of two coats, an internal and an exter-
nal one.
   The external coat  is somewhat irregular on its surface, from
its connexion with the adjacent  cellular substance;  and  has a 
ANATOMY OF THE ABSORBENT SYSTEM.
285
 filamentous appearance more deeply, which has been considered
 as fibrous, or muscular, by some anatomists, owing to its con-
 traction upon the application of certain stimulants.  The inter-
 nal membrane is extremely fine and perfectly transparent, and
 is remarkable for its frequent duplications, whereby a system
 of valves  is produced resembling  those  of  the veins.   These
 valves are generally of a semi-lunar or parabolic shape, and are
 arranged in pairs, though according to Lauth,* some of them are
 circular, and do not close the canal entirely.  The pairs are not
 placed at stated distances from one another, but vary in differ-
 ent parts of the body; in some  places there are several in the
 course of an inch, and in others not one pair.  As a  general
 rule, they  are less  frequent as the trunk  increases in  magni-
 tude;  hence, the  thoracic duct has but very few of them.   The
 valves, by having their semi-circumference fixed, while the dia-
 meter is loose and inclined in the course of the circulation, pre-
 vent the retrograde movement of the contained fluid.  The en-
 largement of the trunk at their  outer face into sinuses, resem-
 bling those at the valves of the veins, gives also to the lympha-
 tic trunk the knotted condition when it is fully injected.
   The coats of the lymphatic vessels, though very thin, are yet
 dense and extremely strong, much more in proportion than
 those of any other tubes.  They are both extensible and elas-
 tic,  possess striking powers of spontaneous contraction in the
 living body,  and also in the dead, but to a less extent.   They
 are furnished with arteries and veins, and  probably with nerves
 also, from  their sensibility in a state of inflammation.  And, as
 they stand in need of a similar organization  with other canals,
 their parietes are said also to have  lymphatics.
   The absorbent vessels  are, by  some, divided into lacteals and
 lymphatics,t the  first  term expressing  those  which convey the
 chyle from the intestines, and the second  such as  are found in
 other parts of the  system.  As  the difference is  more in the
 fluid conducted than in the structure of the vessels themselves,
  * Loc. cit.
  t This division has been handed down from the time of Bartholine, who, not
suspecting the absorbing powers of the lymphatics, held them only as organs of
 circulation for restoring to the heart the serum of the blood.  The sagacious
mind of the late Dr. W. Hunter first imagined their absorbing powers, and esta-
blished the theory of their identity of function, in this respect, with the lacteals.
The priority of the theory was warmly contested for Dr. Monroe, of Edinburgh. 
286
CIRCULATORY SYSTEM.
the division is rather superfluous.  There is also a distinction
of the lymphatics, arising from their situation, as in the veins;
some of them are called superficial, and the others deep-seated.
The arrangement upon which this nomenclature depends, is
found in the head, trunk, extremities, and in the most of the vis-
cera.  The deep-seated trunks are the largest, but the least nu-
merous.

                  Of the Lymphatic Glands.

  The Lymphatic or Absorbent Glands  or  Ganglions, some-
times called waxen kernels in common language, are an appen-
dage of a  very important description  to the absorbent system.
They are flattened ovoidal bodies, of  a reddish ash colour, in-
durated so as to afford a strong resistance to  pressure, and of a
variable volume, from a line to twelve lines in  their long dia-
meter.  They are found principally in clusters  or chains, and
more abundantly in the neck, in the groin, in the arm-pit, in the
mesentery, and about the bifurcation of the trachea.
  The lymphatic vessels, in their course towards the thoracic
duct, have to pass through  one or more of these glands.  This
rule is almost universal; some exceptions, however, to it, in the
ease of the lower extremity, have been stated by Mr. Hewson,
and in the case of the back, by Mr. Cruikshank:* the latter be-
lieves  Mr. H. to have been under a  misapprehension in this
statement concerning the extremities, as it had not been verified
by the result of his own investigations.  The vessels that enter
into the glands are called  vasa inferentia, while those that de-
part from them are the vasa efferentia.  As, owing  to the jux-
taposition of many of these glands, the vessels  between them
are very short, this distinction would likewise seem almost su-
perfluous, because there is scarcely space to apply the term ef-
ferentia, before the same vessels enter the consecutive gland.
thereby becoming  inferentia.  For the most part, the vasa in-
ferentia are more numerous and somewhat smaller than the ef-
ferentia.   The former, as  they enter the gland, radiate into
smaller branches, while the latter are formed from the junction
of smaller branches.

       * Anat. of Absorb. Vessels, second edit. p. 79. London, 1790. 
ANATOMY OF THE ABSORBENT SYSTEM.
287
  Each lymphatic gland is surrounded by a capsule, resembling
condensed cellular substance, which adheres very closely to the
gland, and from which cause many anatomists  are disposed to
deny its existence, at least as a distinct membrane.   They are
also abundantly furnished with arteries and with veins destitute
of valves; but though they are penetrated by nervous filaments,
it is not yet satisfactorily ascertained that any remain with them;
it is, however, more probable than otherwise.  Their connexion
with the surrounding cellular substance is sufficiently loose to
permit them, in certain parts, to be slid moderately backwards
and forwards.   When this motion is arrested, it is from inflam-
mation about them.
   The capsule of the lymphatic gland, like that of other glands,
sends processes within to keep its parts together, and to  con-
duct the blood vessels.  It also contains a peculiar fluid called,
by Haller, succus proprius, which is principally found in young
animals, diminishes as they advance in age, and finally disap-
pears.   It is of various colours, but more frequently white; it
appears  to have globular particles in  it, which the late  Mr.
Hewson, for divers reasons, thought to become afterwards the
red globules of blood.
   When a lymphatic gland  is injected with quicksilver, it ap-
pears to be made up by the minute branching of the vasa  infe-
rentia, and the roots of the vasa efferentia, the former being con-
tinued into the  latter.  There is also some appearance of small
cells intermediate to these two orders of vessels.   All anato-
mists admit the former opinion; but many reject the latter, un-
der a presumption that the appearance is delusive.   The argu-
ments, however, seem to be in favour of their existence.   Mr.
Cruikshank,* whose address in these matters was  certainly of
the first order, declares that he never failed to perceive them,
and particularly well, just as the mercury was entering the
gland.   This arrangement is still^more readily made out in
animals, as the  horse, ass, mule.   It also seems, from his ob-
servations, that when there are more than one vas inferens and
efferens, there  are  cells for each set, which  are kept  distinct
from the cells of the others,  though they communicate freely
with their  cognates.  Mr. Abernethy's investigations, on the
* Loc. cit. p. 85, pi. iii. 
288
CIRCULATORY SYSTEM.
mesenteric glands of whales, coincide with the views of Mr.
Cruikshank: he states,indeed, the cells as being large spherical
bags, into which the lacteals plainly  open.   The  celebrated
Mascagni also acknowledges, and, in fact, describes the cellu-
lar structure of these glands,* which he had ascertained both by
quicksilver and  by wax injections.   The improved notions  of
modern anatomy, upon what is called the erectile tissue, that is,
the cells intermediate to arteries and veins, as in the penis and
other places, now considered rather  as the dilated extremities
of vessels, would also assist in warranting the opinion advo-
cated.  The celebrated Ruysch thought that he had  discovered
acini in the lymphatic glands, and sent his injected preparations
illustrative of them to Boerhaave.  Some idea of the enthusiasm
of the old anatomists may be conceived by his  saying, " Quan-
do jam clarius et perfectius videbam hsec  omnia, prae gaudio
exsiliebam."
   When the absorbing powers of the lymphatics had been
 established by Dr. W. Hunter, they were for a long time con-
 sidered as the exclusive functionaries in this operation; and the
 opinions  previously entertained had  sunk into such disrepute,
 from some experiments of  Mr. John Hunter,t that  they were
 considered rather as food for literary research  and curiosity
 than for deliberate adoption.  In the  year 1809, M. Magendie
 reported his  experiments on absorption, which seemed  to fa-
 vour the notion that the veins also assisted in this office,  a the-
 ory  as  ancient as Galen.   The more recent observations of
 Fohman, in 1821, and Lauth, in 1824, on the communications
 of the lymphatics with  the veins, in the midst of the tissues of
 organs, and in the lymphatic glands, seem now to explain  away
 again the theories of the absorbing powers of the veins, and to
 reinstate the  lymphatics in  their reputed  exclusive functions.
 It is  also stated that an anatomist of  Florence, M. Lippi, has
still more lately found several large lymphatic trunks entering
into the ascending cava.  The connexion of the lymphatic sys-
tem with the  vena cava ascendens, and also with the external
* Vasor. Lymph. Hist.
f Med. Commentaries. 
ABSORBENTS OF THE HEAD AND NECK.
289
iliac veins has been farther  demonstrated  by certain prepara-
tions, exhibited by M. Amussat to the Academie Royale.*   M.
Fodera has, however, again brought  the subject under discus-
sion, by multiplying the active agents of this function, and says,
that his experiments prove  that all organized tissues enjoy it,
and not certain parts only, as  has been heretofore supposed ;t
from which it results that most of the  rules  in regard  to  the
application of  local remedies are inexact, and that  we  should
have more regard to the thickness and density of tissues, to  the
quantity and rapidity of their circulation, than to  simple  lo-
cality4
                      CHAPTER  VI.


  OF THE SPECIAL ANATOMY OF THE ABSORBENT SYSTEM.

      SECT. I.--OF THE ABSORBENTS OF THE HEAD AND NECK.

   The Superficial Absorbents of the head are found in compa-
 ny with the several branches of the temporal, the occipital, the
 frontal, and the  facial arteries, and, in order to  get  into the
 lymphatic trunks leading to the thoracic duct, follow or rather
 reverse the course of their respective arteries.   There  are  at
 least two absorbent  trunks  for  one  arterial, and frequently
 more: those on the face are more abundant than such as are on
 the side of the  cranium, owing to the excess of cellular sub-
 stance on the former.   The absorbents  of these  two regions
 anastomose freely beneath  the external  ear, between the skin
 and the parotid gland.

  * Am.  Med. Jour. vol. i. p. 422.
  t Recherches Experimentales sur l'Absorption et l'Exhalation. Paris, 1824.
  t For a most interesting and instructive series of experiments on the laws and
phenomena of absorption, see Philadelphia Journal of the Medical and Physical
Sciences.  Nos. 6 and 10.  The experiments were executed by Drs. Lawrence,
B. H. Coates, and Harlan, of this city.
  Vol. II.—26 
290
CIRCULATORY SYSTEM.
   The Deep Seated Absorbents of the head have been followed
to the membranes of the brain, but not farther.  Ruysch ob-
served them between the tunica arachnoidea and the pia mater,
inflated with air, and called them vasa pseudo-lymphatica. Lan-
cisius, Pacchioni, and others, assert their having found them in
the pia mater.   Doubts, however, are cast upon these several
observations, owing to  such  vessels not having been injected
with quicksilver, and from the want of a valvular appearance in
them; also  from the want  of lymphatic glands in the brain.
Their existence, however, would seem to be sufficiently proved,
both  from general analogy, and from  affections of the  brain
producing swellings  in  the glands of the neck.  On the dura
mater they  have been traced along the  course of its arteries.
They descend from  the interior of the  cranium into the neck,
along the carotid  and  vertebral  arteries.  The  absence of
lymphatic glands  in the cranium  may be accounted for from
the fact, that the ready  tendency of these organs to swTell upon
slight causes of irritation, would  have rendered the  individual
liable to  death, from  compression of the brain, by their tume-
faction.  Mr. Cruikshank has found lymphatic glands in the ca-
rotid canal.

   The Deep Lymphatics of the face, as those from the interior
of the nose,  of the orbit, of the  tongue and mouth, attend  the
arteries which respectively supply those  parts.
   These several absorbents, from the surface and from the  in-
terior of the head,  descend to the base of the cranium, and then
begin to  pass through the chain of lymphatic  glands situated
along the course of the great  blood  vessels of the neck.  They
lie, for the  most part, under the sterno-mastoid muscle, and,
when successfully injected, are thought to form the  most bril-
liant plexus  of absorbents in  the whole  frame.  On  each side
of the neck, one or more common trunks are, at length, formed;
that on the  left side joins the Left Thoracic Duct  near its ter-
mination,  while the one on the right assists in forming the duct
peculiar to that  side, the Right Thoracic Duct, or, more pro-
perly  called, the  right Brachio Cephalic.
   The lymphatic vessels of the  muscles  of the  neck, and those
of the thyroid gland, enter  into  the trunks of the  neck.  Ac-
cording to Mr. Cruikshank, those of the thyroid gland may be 
              ABSORBENTS OF THE HEAD AND NECK.           291

readily injected by plunging a lancet at random into  its sub-
stance, and then introducing air or quicksilver.


          Of the Absorbent  Glands of the Head and Neck.

   The only claim  of lymphatic glands to an existence in the
cavity of the cranium, is founded upon the supposition  that the
Pineal, the Pituitary, and Pacchioni's Glands are of this cha-
racter; but it is far from being established,  and  there seems in-
deed to be some doubt whether the glands found in the carotid
canal, by Mr. Cruikshank, are not the carotid ganglion of the
Sympathetic, lately noticed by Laumonier.
   On the external surface of the cranium,  over the insertion of
the sterno-mastoid muscle, there are from four  to six of a small
volume;  on the face there is one or more small  ones, below the
zygoma, and from two to  four on the external surface of the pa-
rotid;  there is one or more small ones situated  in the substance
of the parotid  gland, which, according to Burns, are generally
the seat of tumours  falsely attributed to  the parotid itself.
There are also some small  glands along the facial artery as it
ascends  from the base of the jaw to the corner  of the mouth.
   On the neck there are two or more small glands, immediately
under the skin of  the symphysis of the jaw, and eight or nine
around the submaxillary gland.  The most numerous congeries
of glands on  the neck is, however, along its great blood vessels,
and covered  more or less by the sterno-mastoid  muscle, being
principally between its posterior margin and the anterior of the
trapezius.  Along the latter line there  are about twenty, in ad-
dition to six just above the superior margin of the clavicle.  On
the trachea, just above the sternum, there are four, forming the
upper end  of a series which descends along the oesophagus and
trachea to the root of the  lungs.


SECT. II.--OF THE ABSORBENTS OF THE UPPER  EXTREMITIES AND OF
       THE CONTIGUOUS PARTS OF THE TRUNK  OF THE BODY.

   The superficial  absorbents of the  upper extremity are very
numerous, and lie between its skin and aponeurosis.  They be-
gin at the ends of  the fingers and  thumb;  there being two or 
292
CIRCULATORY SYSTEM.
 more branches for each, both before and behind.  The posterior
 branches pass to the back of the hand  and of the fore  arm:
 some of them, more especially those from about the thumb, run
 up along the radial side of the fore arm to the bend of the  arm ;
 but by far the greater part of them incline very gradually in a
 semi-spiral manner towards the  ulna, and then to the front of
 the fore  arm.
   Such of the superficial vessels  as come from -the front of the
 fingers and hand, continue to ascend straight up the  fore arm
 to  its bend.  These vessels  of the  fore arm are  so numerous
 that for every few lines there is an ascending trunk on its cir-
 cumference: some of them coalesce, others form plexuses, and
 their number is much reduced at  the elbow.
   From  the elbow the superficial lymphatics ascend to the ax-
 illa in fifteen or twenty parallel  trunks, along the internal  mar-
 gin and the front surface of the biceps flexor cubiti.  The outer
 side of the arm  has comparatively but  few absorbent trunks
 upon it, but some follow the course  of the  cephalic vein, pene-
 trate with  it into the axilla, and then join the inferior lympha-
 tics of the  neck.

   The Deep Absorbents of the upper extremity attend the ar-
 teries, and are at least two  for  each principal  artery.   They
 anastomose with the superficial  ones at intervals, and at last
 terminate  in the axillary  glands.  As they follow strictly the
 course of the arteries, a farther specification is needless.

   The Superficial Absorbents of the contiguous portions of the
 trunk of  the body are not  by any means so numerous as  those
 of  the upper extremity; they consequently are more distant
 from one another, and they also go along in a more serpentine
 manner.   From the nape  of  the  neck to the lower part of the
 loins they all converge to the arm-pit.   The absorbents which
 are situated on  the front  of the  pectoralis major  muscle, and
 those on  the side of the body from the arm-pit to the  hip, also
 converge to the axilla.  In regard to the two latter places, how-
ever, some  of their absorbents, by penetrating the parietes of the
thorax or  abdomen, respectively join  the  internal absorbent
trunks of these cavities.
  These several lymphatics from the upper extremity and from 
             ABSORBENTS OF THE LOWER EXTREMITIES.         293

the trunk, traverse the axillary glands, and are successively re-
duced in number to  four or five voluminous trunks, which sur-
round the subclavian artery.  While in the axilla they are re-
enforced by the deep lymphatics from  beneath  the  pectoralis
major, the latissimus dorsi, and the shoulder.  Their number
being again reduced, they go along the subclavian vein over the
first rib; those of the left side open either into the thoracic duct
at its termination, or into the subclavian vein near it; but those
on the right are finally assembled into  the  single large  trunk,
brachio-cephalic, which  discharges  into the  angle of junction
of the right internal  jugular and subclavian vein.


          Absorbent Glands of the Upper Extremity.

   These glands are rarely found on the fore arm, but when they
do exist, it is in the course of the deep absorbents, and they are
very small, and but few.   From one to four are found scattered
on  the front of the  elbow  and internal condyle.  From four
to seven exist  along the sheath of the brachial vessels and
nerves.
   The axillary glands are very numerous, and of different sizes;
they are dispersed throughout the cellular substance of the ax-
illa,  reposing on the  serratus major anticus, between the pecto-
ral muscles and those of the shoulder, and being, for the most
part, below the axillary  vessels  and nerves, but some reposing
immediately upon  them, and forming a  chain from the lower
part of the axilla  to  the clavicle.  Their number is from fifteen
to thirty-five or forty.   All the absorbents which observe the
route of the axilla to reach the thoracic duct have to pass through
these glands.


SECT. III.--ABSORBENTS OF  THE INFERIOR EXTREMITIES, AND OF THE
        CONTIGUOUS  PARTS OF THE TRUNK OF THE BODY.

  The superficial absorbents, like those of the upper extremity,
are placed  between the skin and the aponeurosis, in the cellular
tissue that contains the subcutaneous veins.  They are also very
abundant, and are found every few lines on  the circumference
                            20* 
294                 CIRCULATORY SYSTEM.
of the limb; they are, however/more numerous internally than
externally, and, for the most part, run upwards.
   Those on the inner or anterior side of the limb are  first per-
ceived on the back of the toes and foot. They incline over the
front of the ankle, and its internal face to  the inner side of the
leg; they then ascend over the inner side of the knee, and along
the same side of the thigh to the groin.  The superficial absorb-
ents of the back of the lower extremity are first  perceived on
the sole of the foot.  They ascend along the back of the outer
ankle and of the  leg above the knee;  they then  incline semi-
spirally inwards,  so as to bring themselves to the front of the
thigh.   These several absorbents, though there  are  but few on
the foot, augment continually in number by new accessions in
their  ascent.  All those on the posterior internal face.of the
thigh  wind over its internal side, while such as are on its poste-
rior external face wind over the outer side, to reach the ingui-
nal glands.

   The Deep Absorbents adhere to the arteries, being  at least
two to each, and adopting the same distribution and nomencla-
ture.  The anterior tibial set begins in the sole of the foot,  and
arises to its back  between the two first metatarsal bones;  ano-
ther branch begins on the dorsum of the foot.  The first pur-
sues the course of the anterior tibial artery through the inter-
osseal ligament to the ham, the second frequently joins the pero-
neal absorbents about half way up the leg.  The posterior tibial
and the peroneal absorbents, as they cruise along their respective
arteries, do not require any farther comment.  There is a fourth
set of these deep absorbents, amounting to  two or three in num-
ber, which attend  the external saphena vein, and come from the
external side of the foot. Getting between the heads of the gas-
trocnemii muscles, they are  l^-enforced by other trunks from
this muscle; some of the  branches then associate  themselves
with the superficial lymphatics, and others  penetrate  the ham,
so as to join the deep trunks there.
   The deep absorbents of the leg coalesce  partially in  the ham,
and ascend along the popliteal artery.   On the thigh, there are
from four to eight of these trunks  attending the  femoral artery,
and receiving additions as the latter detaches branches. 
ABSORBENTS OF THE LOWER EXTREMITIES.         295
  There are two or three lymphatic vessels on each side of the
penis, which begin at its glans and prepuce, and traversing the
length of this organ, wind above the external abdominal ring to
join the nearest inguinal gland. There are several from the side
of the scrotum and perineum, which ascend along the chord and
thigh to join also the nearest inguinal gland.   In the female,
those of the labia externa and clitoris correspond with those of
the  scrotum and penis.
  The superficial absorbent trunks, from the lower front of the
abdomen, are not numerous;  they descend and converge also
to the inguinal glands.   Some  of those from the loins, such as
do not ascend  to the axilla, advance to the  inguinal glands.
Those of the buttocks do the same.


           Absorbent Glands of the Lower Extremities.

  Absorbent Glands,  below the knee, are not abundant, or, in-
deed, very common;  yet, one  or two exist sometimes in the
course of the anterior tibial artery in the upper part of the leg.
The popliteal glands are three or  four; they are small, and
scattered at wide intervals in the fat of the ham around its ves-
sels.  From  the latter to  the groin, they are not  usually found
at all.

  The Inguinal  Glands are amongst the largest in the system;
they repose along the  anterior margin of Poupart's ligament and
a little below, and are readily felt beneath  the  skin.   The su-
perficial vary in number, in different individuals, from seven to
twenty,  being  more  numerous as  they are  smaller,  and are
placed between  the laminae of the fascia superficialis.  They
receive, first of  all, the  superficial lymphatics  of all the  parts
mentioned.   The deep-seated are smaller,  are a  little  lower
down on the thigh,  and  lie along the course of the  femoral ar-
tery, beneath the aponeurosis of the thigh ; they are from  three
to seven in number, but are much less constant than the super-
ficial. 
296
CIRCULATORY SYSTEM.
          SECT. IV.--DEEP ABSORBENTS OF THE PELVIS.

   The Deep Absorbents of the parietes of the pelvis, as in other
 cases, attend the  arteries of the part and have the same names.
 The obturators come from the heads of the adductor muscles,
 and, passing through the  obturator  foramen, end in the hypo-
 gastric glands.  The ischiatics come from the small muscles on
 the back of the hip joint, and getting into the  pelvis along with
 the sciatic artery, they also terminate in the hypogastric glands.
 The gluteals come from the three gluteal muscles, and entering
 the pelvis along with the artery at  the  superior margin of the
 sciatic notch, they likewise terminate in the hypogastric glands
 along with some  vessels from the anus and the perineum.  The
 ilio-lumbar, the sacral, and the circumflex iliac absorbents, also
 follow their respective arteries and terminate in the nearest
 glands.
   The absorbents of the Testicle are numerous and large: ac-
 cording to Dr. W. Hunter,* they can sometimes be very com-
 pletely injected by a pipe thrust into the substance of the testi-
 cle, and, according to Cruikshankf,  very advantageously from
 the vas  deferens, which  has  succeeded  in  my own  hands.
 They form two layers, one superficial  coming from the tunica
 vaginalis testis, and the other from the substance of the gland.
 They, finally,  unite into some  six or eight trurrks, whichj as-
 cend with the chord through the abdominal canal.   Occasion-
 ally, one or more of them is as large as a crow-quill.   By fol-
 lowing the course of the spermatic artery, they at last terminate
 in the lumbar glands.
   The deep absorbents of the  Penis accompany the arteries,
 and, therefore, either get into the pelvis beneath the symphysis
 of the pubes, or along the crqra and the tuberosities of the is-
 chia; hence, a chancre on the prepuce  causes bubo, while one
 on the glans very rarely does,  and yet the  constitution will be
equally affected.§   These absorbents terminate in the hypogas-
 tric glands.
   The deep absorbents of the Clitoris follow, in the same way,
 the internal pudic artery.
* Loc. cit.                        f Loc. cit. p. 155
$ Mascagni, loc. cit.                 § Cruikshank, loc. cit. 
               Deep absorbents of the pelvis.             29?

  The absorbents of the Urinary Bladder  are also numerous,
and pass in several trunks from  its sides  to the hypogastric
glands.   Those of the prostate gland  and  vesiculae seminales
are associated with them.
  The absorbents of the lower part of the  vagina accompany
the round ligament of the uterus through the abdominal canal,
and, finally anastomose with those of the uterus.  Those of the
upper portion of the vagina  are  immediately associated with
such as belong to the uterus.
  The absorbents of the uterus are not so well seen in the un-
impregnated state, but in impregnation they are so prodigious-
ly numerous, that when injected  with quicksilver, one is al-
most  tempted to  suppose that the uterus consists entirely of
them.   Mascagni's plate on this subject is an exquisite speci-
men.*  As they all terminate in the  hypogastric  trunks, the
latter are in such case as large as goose-quills.f
  The hypogastric plexus, from  these several accessions  from
the parietes and viscera of the pelvis, becomes  very numerous,
and follows the course of the hypogastric artery in ascending
into the loins.
  There are likewise some spermatic absorbents in the female,
called so from attending the vessels of  the same name.  They
come from the ovarium, the Fallopian tube, and the round  liga-
ment, to terminate in the lumbar glands; they anastomose be-
low with those of the uterus.


                Of the Glands of the Pelvis.

  Some few glands lie  beneath  the gluteus maximus muscle,
but the majority are within the pelvis.   Those which are called
the External Iliac are at least six, frequently more, and extend
from Poupart's  Ligament to the lower  part of the loins, being
planted along the external  iliac artery, both above and below.
The Hypogastric or Internal  Iliac Glands are rather  more nu-
merous than the others, and form a chain along the hypogastric
artery.  The latter are much disposed to form large indurated
masses from diseases of the rectum, uterus, and bladder.}

  * Loc. cit.        f Cruikshank, loc. cit.       X Cruikshank, loc. cit. 
298                 circulatory system.
      SECT. V.—ABSORBENTS OF THE ORGANS OF DIGESTION.

  The Absorbents of the Stomach are very numerous, and lie
in two planes; one is superficial, being immediately beneath the
peritoneal coat,  and the other is profound,  being placed be-
tween the muscular and the mucous coat.   They are, finally,
assembled into three divisions, which follow  the course of the
principal blood vessels of this organ.
  One division,  coming from the anterior and  the posterior
faces of the  stomach, converges  to  its  lesser  curvature, and
passes through some six or eight small glands in the adjacent
portion of the lesser omentum.  Inclining to the  right of the
cardiac orifice, they then pass through some glands common to
them and to the  deep lymphatics of the liver.  Their numbers
being  reduced,  they then descend behind the pancreas, and
terminate in the  thoracic duct near the cceliac artery.
  The second division comes  from the left inferior portion of
the stomach, and from its greater extremity, and, blending with
the absorbents of the spleen and pancreas, goes with them into
the thoracic duct.
  The third division comes from the right inferior portion  of
the stomach,  and, assembling towards the pylorus, are subse-
quently mixed with  some of the absorbents of the liver and of
the small intestines, and go along with them into the thoracic
duct.

  The Absorbents of the Great  Omentum  join  those of the
stomach and of the colon, at the points  most convenient to
them.

  The Absorbents of the Small  Intestines,  like  those of the
stomach, are both superficial and deep, and from the function of
conveying chyle, have been called  lacteals, or chyliferous ves-
sels.  As the chyle, however, can only be absorbed by the deep
ones; and, as they and the superficial have common trunks, as
they also absorb, from the intestines, fluids not converted into
chyle, there seems to be no necessity for distinguishing them
by a particular epithet.   The deep are in the cellular coat of
the intestine, and follow  the ramifications of the arteries, being 
ABSORBENTS OF THE ORGANS OF DIGESTION.         299
double their number.   The  superficial, being  immediately be-
neath the peritoneal coat, run for some distance, longitudinally,
on the gut, and then turn off to the mesentery  at right angles.

  On the mesentery these absorbents are not  rigidly bound  to
the course of the blood vessels; they converge  in a slightly tor-
tuous manner from its circumference to its root.   They anasto-
mose with one another, by which their number is reduced;
and they also have to pass through the series  of mesenteric
glands.  The lacteals of the duodenum and jejunum are larger
and more numerous than those of the  ileum, in the proportion
of the greater extent of the  internal surface of the former intes-
tines, from the number of their valvulas conniventes.  The ves-
sels of the mesentery, after having cleared the series of glands,
and held some intercourse with the lymphatics of the spleen,
liver, stomach, and pancreas,  are  reduced at  last into one or
more large trunks, which, observing the course of the superior
mesenteric artery, empty near the root of the latter, but some-
times lower down, into the thoracic duct.

  The absorbents of the Large Intestines are much less nume-
rous than those of the small.  They are also superficial and deep,
and observe  the course of the blood vessels.   Those from the
right portion and middle of the colon join the lacteals of the me-
sentery,  while such as  belong  to the sigmoid flexure follow the
inferior mesenteric artery up to the lumbar glands.  Those of
the rectum go partly into the lumbar and partly into the hypo-
gastric glands, and as its blood vessels are more numerous than
those of other portions of the large intestines, its absorbents are
in the same proportion.*

  The Absorbents of the Liver are exceedingly numerous,  and
are also injected with unusual ease from the larger into the smaller
trunks, from  the  imperfection of the  valvular arrangements,
They are also superficial and deep.

  The Superficial Absorbents of the upper surface of the liver
run  in several divisions, the number of which is unsettled.
* Cruikshank, loc. cit. 
300
CIRCULATORY SYSTEM.
 Those near the middle front of the liver  assemble into  six or
 more trunks, which ascend  the suspensory ligament, and enter
 the thorax between  the  diaphragm  and the sternum.   They
 are joined by several trunks from the diaphragm, and continu-
 ing to ascend up the anterior mediastinum between its laminae
 behind the sternum, they are re-enforced  by contributions from
 the pericardium, from the thymus gland,  and from the anterior
 parietes of the thorax.  The division then crosses the upper end
 of  the descending cava, and  those from  the two sides assem-
 bling, they go in one or more large  trunks along the left vena
 innominata,  and finally empty into the left thoracic duct near
 its  termination.  Sometimes they enter into the  right thoracic
 duct.  It occasionally happens that a  detachment of this divi-
 sion, instead of ascending through  the mediastinum,  is directed
 towards the  coronary ligament of the liver;  and being there
 joined by other vessels, it enters immediately into the thoracic
 duct at the upper part of the abdominal cavity, or at the low-
 er part of the thorax.
  Another division  comes from the upper surface of the right
 lobe, and gaining the right lateral ligament, penetrates into the
 thorax through the diaphragm, and advancing along the  costal
 margin of this muscle,  terminates in the first division under the
 sternum.  Sometimes one of its branches, thrice as large as a
 crow-quill, runs backward to the spine, and is inserted into the
 thoracic  duct behind  the oesophagus, without passing  through
 any gland; there are also, occasionally, several  other arrange-
 ments of the trunks of this division.*
  Another division comes from the upper surface of the left lobe
 of the liver, and its trunks, advancing to  the left lateral  liga-
 ment, get into the thorax through the diaphragm.   Some of the
 trunks then run forward on the convexity of this muscle, to ter-
 minate in the trunks under the sternum, while others retire  back- *
 ward to end in the glands around  the oesophagus, immediately
 above the diaphragm.
  There are various departures from this general arrangement
 of the absorbents on  the  upper surface of the liver; as their
trunks invariably reach the thoracic duct, ultimately, the parti-
 cular routes do not seem to be rigidly  fixed.
* Cruikshank, loc. cit. 
ABSORBENTS OF THE ORGANS OF DIGESTION.
301
  The Superficial Absorbents of the under  surface of the liver
present, also, diversities,  but they are  seldom arranged into so
many divisions as those of the upper surface.   They communi-
cate freely with the latter, and  also with the profound, and,
finally, assembling in the  transverse fissure, they descend along
the capsule of Glisson to  join and anastomose with the contigu-
ous trunks from the alimentary canal, from the pancreas, and  the
spleen.

  The Deep Absorbents of the liver follow the branching of the
vena portarum,  and, emerging at the  transverse fissure, pass
through the glands in the capsule of Glisson, associating them-
selves at the same time with the superficial trunks, and having
a common termination with them.   By putting a ligature around
the vena  portarum of a  living animal, many of them are  in-
cluded in it; they then become exceedingly turgid, and are seen
to diverge through the liver like the pori biliarii.
  The liver is said to be  more abundantly furnished with absor-
bents than any other viscus.

  The Absorbents of the spleen are also superficial and deep-
seated: The former are  between the peritoneal and the proper
coat, and  are injected with some difficulty in  the  human sub-
ject, but  are very demonstrable and numerous in  the calf.
The latter emerge at the fissure of the spleen,  and, traversing
the glands that lie along  the course of the splenic artery, re-
ceive successively the absorbents from the pancreas.  They,
finally, end in the thoracic duct, after reciprocal junctions, and
anastomose with the vessels from the stomach and liver.

  The Absorbents of the Pancreas are also numerous, and may
be injected, contrary to their circulation, from those of the liver.
They arise from the substance of the pancreas, like its vessels,
by  short trunks, which join those of the Splenic Plexus at right
angles.

  The Absorbents of the Kidneys are  superficial and deep; the
former, though numerous, are too small in the  healthy state of
these  organs to be well seen, but they become very distinct
from disease, and  converge from its  periphery to its fissure.
   Vol. II—27 
302
CIRCULATORY SYSTEM.
The deep absorbents  accompany the vessels, and, emerging
with them at the fissure, are joined with the superficial; they
all  then run along  the emulgent vessels,  and have frequent
anar/omoses with those  of the testicles  or ovaries, andV with
those of the capsulae renales.  These absorbents may be filled
by putting a pipe into the excretory duct of the kidney.

  The absorbents of the Capsulae Renales unite to those from
the kidneys, and, therefore* terminate with  them in the lumbar
glands.

          Of the Absorbent Glands of the Abdomen.

  The cavity of the abdomen contains many more glands than
any other region of the body, on  account of the very great ex-
tension of the serous system in it, of the functions exercised by
its viscera, and of its being traversed by the absorbents of the
lower extremities.   Many of  these Glands have  already been
described under the denomination of hypogastric, and external
iliac; in addition to which there are a few  between the laminas
of the mesorectum in front of the sacrum.

   The  Mesenteric  Glands  are  exceedingly  numerous, and
amount to between one and two hundred; they begin at an
inch or two from the small intestines, and may be traced to the
root of the mesentery, being placed  between  its layers, on the
 convex side of the  upper mesenteric artery.  As the intestinal
 canal is longer in some individuals than in  others, they are pro-
 portionately more  numerous. Their largest size  seldom  ex-
 ceeds that of an almond: those belonging to the jejunum are
 rather more developed than such as belong to the ilium, and
 they all augment in size as they  approach  the root of the me-
 sentery.

    The  Glands of the Mesocolon are placed between the laminae
 of this membrane, near the intestine; they receive the absorbents
 from the large intestines, are much  smaller than those of the
 mesentery, and their number seldom exceeds fifty.  Some few
 of them are situated near the root of the mesocolon.  They are
 by no means  so disposed to tumefaction from scrofulous affec- 
           ABSORBENTS OF THE VISCERA OF THE THORAX.       303

tions as those of the Mesentery.  It is stated by Winslow, that
he demonstrated to the Academy of Sciences at Paris, chyle
in the absorbents of the Mesocolon; this fact will assist us in
accounting for the effects of nutritive glysters.

   The Gastro-Epiploic Glands are  situated between the lami-
nae of the omenta, where they join  the curvatures  of the sto-
mach.   Their number seldom exceeds four or five for  each
curvature, and they receive the lymphatics of the stomach and
omenta.

   The Caeliac Glands are those  which belong to the liver, the
spleen, and  the pancreas; they follow the course  of the blood
vessels of these organs, and are  traversed by their absorbents.
The trunk of the vena portarum is surrounded by them, and
Mr. Cruikshank says, that he has seen the biliary and pancre-
atic ducts in a state of compression  from their tumefaction.

   The Lumbar Glands are very numerous and large; they are
scattered over the  whole region,  from the base of the sacrum to
the pillars of the diaphragm, lying on each side of the bodies of
the lumbar vertebrae,  and in front of the abdominal aorta and
vena cava, being concealed by the root of the  mesentery and
of the mesocolon.  They may be considered as continuations
of all the preceding congeries of glands in the abdomen, and,
therefore, when  they, along with the vessels leading to them,
are successfully injected, they form so thick a plexus of absorb-
ents, reaching from the pelvis to the concavity of the diaphragm,
that the great  blood vessels  can scarcely be  seen for  them.
Many of the vessels reaching from one to another, are as large
as a crow-quill.


     SECT. VL--ABSORBENTS OF THE VISCERA OF THE THORAX.

   The Absorbents of the Lungs are  thought to be next in abun-
dance after those of the liver, and are likewise divided into two
sets, the superficial and the  deep-seated.  The former are be-
neath the pleura pulmonalis.   Mr. Cruikshank* says, that they
• Loc. cit. p. 194. 
304
CIRCULATORY SYSTEM.
are not always to be found, though commonly he has readily
shown them covering with their meshes the whole external sur-
face of the lung.  The larger meshes follow the interstices of
the lobules, and within them are others  of extreme delicacy.
The same author states, that one of the easiest methods of find-
ing them, is to inflate the lungs of a still-born child, from  the
trachea, and the air passing  from its proper cells, will get into
the absorbents; a puncture being then made into one of the lat-
ter, quicksilver may be very readily introduced.  Some of their
trunks penetrate to the bottom of the fissures of the lungs, and
pass through the  glands  there, while others continue more su-
perficial along the internal face of the lung, and so reach  the
bronchial glands.
  The deep absorbents of the lungs  observe  the course of the
pulmonary vessels and of the bronchia.   They arise from the
substance of the lung, anastomose very freely with the  superfi-
cial  vessels, and,  in parting from  the lung, pass through  the
bronchial glands, where they are joined by the superficial.
  By the junction of the branches from the left lung, three con-
siderable trunks are formed; one, which is  sometimes the size
of a goose-quill, is inserted into the thoracic duct, immediately
behind the bifurcation of the  trachea; another ascends between
the trachea and the oesophagus, to join the thoracic duct near
its termination, and the third joins  the glands belonging to  the
absorbents of the heart.*
  The absorbents of the right lung also coalesce into three prin-
cipal trunks at tlie root of the lung: one of them ascends across
the front of the superior cava, making, in its course, many ele-
gant convolutions, and at length terminates  in the  second trunk
on the left side.t   The other trunks, ascending on the side of
the trachea, and  having traversed their glands, discharge into
the* right thoracic or brachio-cephalic trunk, or else near it into
the right  internal jugular, or into the right subclavian vein.
There are, in these respects,  diversities in different subjects.

  The trunks of the Absorbents of the Heart follow the course
of the coronary vessels, and  distribute themselves by branches
over its whole  surface.  They are, without previous manage-
* Cruikshank, loc. cit.
f Cruikshank, loc. cit. 
ABSORBENTS OF THE VISCERA OF THE THORAX.        305
ment, easily discovered; but if the heart be macerated in water
for several days, so as to become somewhat putrid, the absor-
bents are filled and distended by the gazeous exhalation: on the
puncture of one of these vessels and the introduction of a pipe,
they may all be readily filled.
   There are three principal trunks of these absorbents; one fol-
lows the right coronary artery to the root of the aorta, and then
ascends over the front surface of the latter to the top of its arch,
where  it enters a gland.   The other two trunks follow  the two
principal branches of the left coronary artery, and, coalescing
near its origin, they ascend to the bifurcation of the pulmonary
artery, and from that along the  posterior face of the arch of the
aorta, to enter a gland between it and the trachea.  These se-
veral vessels subsequently traverse the lymphatic glands about
the trachea, common to the heart and to the lungs: and ulti-
mately terminate  under varied circumstances, either directly or
indirectly, in the left thoracic duct, the left internal jugular, or the
left subclavian vein.   Mr. Cruikshank says, that the right coro-
nary trunk empties into  the  lymphatic trunks of  the right side
of the neck, which shows that there is no fixed arrangement.

   The Absorbents of the Pericardium may also be found; they
terminate like the others of the heart, in the bronchial glands,
and are  particularly associated  with  those of the  thymus
gland.

   The  Absorbents of the  Oesophagus are so numerous as to
form a plexus from one end  to the  other of it.  They run into
the bronchial glands, and, therefore, have a common termina-
tion with the absorbents of  the heart and lungs.  Mr. Cruik-
shank says, that  he has reason to believe that he has  seen life
sustained through them alone and the absorbents of the mouth,
in a case where stricture prevailed for some months just above
the cardia, and where the food, after remaining for three or
five  minutes in the oesophagus,  was vomited up.*

   The Absorbents of the Thymus Gland are very abundant in

     * A case sonewhat similar occurred in the practice of Dr. Physiek.
                            27* 
306
■CIRCULATORY SYSTEM.
the infant, but diminish with the rest of the structure in the
adult.: they terminate in the bronchial glands also,


  SECT. VII.--THE ABSORBENTS OF THE PARIETES OF THE TRUNK.

   In  addition to the  absorbents mentioned as belonging to the
internal  and external parietes of the pelvis, there are some
others belonging  to  this cavity, as  the ilio lumbar, the sacral,
and <the circumflex.

   The Ilio Lumbar Lymphatics come from  the parts to which
the artery of the same name is distributed, and, assembling into
jtwo or more large trunks which pass beneath the psoas magnus
muscle, one of them joins ths lumbar glands, and another the
^hypogastric.

   The Sacral Lymphatics arise from the cellular tissue in front
(if the sacrum and from the spinal canal in the latter.  Emerging
through  its foramina.in  front, they terminate in  the lower part
of the lumbar and in the hypogastric plexus.

   The Circumflex Iliac  Lymphatics attending the artery of the
same name, arise from  the lateral inferior parietes of the abdo-
men, in the thickness of  its broad muscles; the several branches
assemble into a few  trunks, which  descend along  the posterior
 margin of Poupart'^s.ligament to terminate in the external iliac
[plexus.

   The Epigastric Absorbents are derived from the inferior an-
terior parietes of the abdomen, along the region of distribution
>of the epigastric artery.  Their trunks coalesce into larger ones,
 and descend along this artery to end in the external iliac plexus,
■near the crural arch.

   The Lumbar Absorbents arise from the muscles of the loins,
from the posterior pari  of those of the abdomen,  and from the
spinal cavity.  Their trunks-correspond  with the lumbar arte-
ries, and passing beneath  the psoas magnus muscle towards the
tgpino, they  terminate in the Jurabar glands. 
          ABSORBENTS OF THE PARIETES OF THE TRUNK.       307

  The Intercostal Absorbents take their origin from the parietes
of the thorax, and following the course of the respective inter-
costal  arteries, pass through some  small glands occasionally
found between the external intercostal muscles near the heads
of the ribs.   They are  there joined by trunks from the spinal
cavity and from the muscles of the back, and afterwards passing
through some small glands on the front of the vertebral column,
they anastomose more or less with one another, and finally ter-
minate in the left thoracic duct.   The absorbents of the pleura
costalis and of the posterior part of the pericardium terminate
in the  intercostals.

  The Internal  Mammary Absorbents have their roots in the
anterior region of the parietes of the abdomen, above the umbi-
licus, where they anastomose with the epigastric.   They ascend,
along with the  internal mammary arteries, behind  the sternal
cartilages, pass through some small  glands, and receive contri-
butions from the anterior extremities of the  intercostal spaces.
Those of the left side, assembling into one or two trunks, cross
in front of the left subclavian vein, traverse the inferior cervical
glands, descend afterwards from this point, and terminate in the
left thoracic duct, or in one of the contiguous trunks of the ve-
nous system.  Those on the right execute the same movements,
but terminate in the right  thoracic duct, or in one of the conti-
guous venous trunks of that side.

  The Absorbents of the Diaphragm are exceedingly numerous,
and very  much connected with  those of  the liver.  The ante-
rior ones join the internal mammary absorbents, while the pos-
terior follow the phrenic arteries, or go  to  contiguous trunks
belonging to the intercostals.   The  front  ones on the right side,
then terminate in the right thoracic duct, while the remainder
go  in the  various routes of the absorbents, with which they are
connected, into  the  left thoracic duct.   They are principally
seen on its upper surface.  Mr. Cruikshank* says, that he once
saw them to the amount of three hundred or more, i'filled with
chyle from the mesentery that had passed  through the substance
.of the liver.  Asellius was, therefore, probably justified by an
* Xioc.xit.p. 9Q. 
308                CIRCULATORY SYSTEM.

accident of this kind, in asserting that the lacteals went to the
liver.

  The Absorbents of the Female Mamma?, like  their arteries
and veins, are superficial and deep; the former attend the ex-
ternal thoracic  blood vessels, and the  latter the internal mam-
mary.   The superficial arise from the circumference of the nip-
ple, from the skin and cellular membrane, and according to the
injections of Mr. Cruikshank, communicate freely with the ve-
sicles of the  tubuli lactiferi.  They run  towards  the  axilla,
having sometimes to pass through some glands which are situ-
ated half way;  they then enter the first series of glands of the
axilla in their direction, and afterwards others successively,
until they terminate in the  lymphatic  trunks  of  the upper ex-
tremity, high up in the arm-pit.   Some few of these superficial
vessels ascend over the  pectoralis major to some glands in the
neck, just above the clavicle.
  The deep absorbents of the mammas arise from their thoracic
face, and penetrating the intercostal spaces, join the  absorbents
that attend the  internal  mammary artery.


           Of the Absorbent Glands in the  Thorax.

  There are, as mentioned, a few small glands in the intercos-
tal spaces near  the heads of the  ribs between the internal and
external intercostal  muscles, intended to receive the lymphatics
of these spaces.  There are also several small ones situated on
the  front of the dorsal vertebras, along the  aorta and the oeso-
phagus, in the posterior mediastinum.  There are also from six
to ten along the internal mammary artery; and some others in
the  anterior mediastinum, along the sternal face of the pericar-
dium.   They are said to be very rarely affected by disease.
  The most considerable and striking glands  in the  thorax are
those called Bronchial or Pulmonary, which receive the absor-
bents of the lungs.  They cluster about the bifurcation of the
trachea, and follow the bronchia for some distance into the sub-
stance of the lungs.   They are from ten to twenty  in number,
and vary in size from an inch to a few lines in diameter.  Till
puberty they have a reddish colour, but  afterwards they be- 
THORACIC DUCTS.
309
come gray, and finally black, following in  these respects the
change of colour in the lungs.  According to Mr.  Pearson,
their complexion depends upon the deposite  of pure carbon.
  In pulmonary consumption these glands are always enlarged,
and look scrofulous.
             SECT. VIII.--OF THE THORACIC DUCTS.

  The Left Thoracic Duct (Ductus Tkoracicus Sinister) is the
main stream  of the  absorbent system  to which almost all the
others are but tributary, and by divers routes ultimately find
their way into it.  It begins about the second or third lumbar
vertebra, in front of its body.  Shortly  after its commencement,
while still in  the  abdomen, it suffers a dilatation more or less
considerable, and varying  in its  shape in different subjects.
This is called the Reservoir of Pecquet, or the Receptaculum
Chyli; the dilatation, however, is  frequently absent, and does
not seem to be an essential part of the structure : in our pre-
parations  at  the  University some have it, and others have it
not.
  The thoracic duct enters the thorax between the crura of the
diapriragm, to the right of, and behind the aorta; it then ascends
on the front of the dorsal vertebras, between the aorta and  the
vena azygos,  in front of the right  intercostal arteries, and be-
hind the oesophagus.   At the  fourth dorsal vertebra it begins
to incline  in  its ascent to the left side, and then  ascends into
the neftk  near the head of the  first rib-,  it rises commonly as
high up as the upper  margin ©f  the seventh cervical vertebra;
it then turns  downwards and forwards, over the left subclavian
artery within the scaleni muscles, and, finally, discharges into
the angle of junction of the left subclavian  and internal jugular
vein.
  The preceding is the most simple, and perhaps the most com-
mon form, under which the thoracic duct  is presented, but va-
rieties are continually occurring in  its place and mode of origin,
in its trunk, and its manner and  place of  termination.  It com-
monly  begins by the union  of three absorbent  trunks; one for
each side  of the pelvis, along with  the  corresponding lower ex-
tremity; and a middle one  for  the chyliferous vessels,  which 
310
CIRCULATORY SYSTEM.
unites with the common trunk of the other  two, a few lines
above its point of formation; on other occasions, the chyliferous
trunks  join it in a  confused manner  by nine or ten distinct
channels.  Sometimes an intricate plexus of several large trunks;
derived from  the lumbar and mesenteric glands,' by the gradual
reduction of  the number of meshes from the successive joining
of trunks; begins to assume, at the crura of the diaphragm, the
form of a solitary trunk, which is the thoracic duct.  The  trunk
of the duct is also  disposed to keep up the anastomosing plan,
even in the thorax; we hence  see it sometimes  dividing itself
into two or three channels of equal size, which unite again af-
ter a shorter  or longer  distance, and perhaps  in  a  little  space
repeat the same arrangement:  sometimes a small arm is sent
off, which runs along for an inch or two, and joins into the  pa-
rent stream ;  sometimes spiral turns are adopted by the thoracic
duct, sometimes nodosities, or small pouches are  formed  on its
sides; sometimes it  is dilated at intervals in its whole circumfe-
rence.  Sometimes it splits into several channels at  its termina-
tion ; one channel terminating in one vein and another in a con-
tiguous one,  of the  several trunks forming  the  vena innomi-
nata ;  on other occasions, instead of entering  into  a venous
trunk of the  left side, it goes into  the corresponding one  of the
right.
   Commonly, it is about the size of a large crow-quill, but some-
times as  large as a goose-quill, or even still more voluminous,
seeming  to  be in  a  varicose state, of which Mr. Cruikshank
mentions an example where it was half an inch in diameter, and
took two pounds of  mercury to fill  it.   There is generally a  pair
of valves at  the termination of  the thoracic duct, or if it be di-
vided into several streams  there is  a pair at the embouchure of
each, to keep the venous blood out of it.   There  are also  valves
in its  length, but they are not  numerous, and vary in different
subjects.
   The thoracic duct, as stated, is  the grand outlet for the lym-
phatics of the left  side of the head and neck, of the left supe-
rior extremity, of the intercostal spaces, of the left side  of the
thorax, of the viscera of the abdomen, and of the inferior ex-
tremities.  Though those  of the visceca of the abdomen  and of
the lower  extremities  have this route, yet, from the observa-
tions  of Mr. Lippi, of Florence, as mentioned, they  have  also 
THORACIC DUCTS                    gjj
some more direct means of getting into the general circulation.
For example, he  has found several large lymphatic trunks
emptying  into the ascending cava, one of them opposite the
third lumbar vertebra; another  into the primitive iliac vein: he
has also found some of the lymphatics of the  liver discharging
into the vena portarum.
  The Right Thoracic Duct, (Ductus Thoracicus Dexter,) as it
is called, but more properly the Right Brachio-cephalic,  after
the name  given by M. Chaussier to the vein, is not more than
an inch long, and  descends  to  empty itself, as  mentioned, into
the junction of the right internal jugular with the right subcla-
vian vein.   It is derived from the lymphatic trunks of the right
side of the head  and  neck, from the right upper extremity, the
superficial lymphatics of the right side of the thorax, the lympha-
tics of the right lung, of the  right side of the diaphragm, and
some of those of the right side of the liver, the courses of all of
which have been detailed.
  Though the single trunk is formed from these several tributary
streams, yet the latter have sometimes several embouchures into
the venous system at or near the point mentioned, and, as on
the other  side of the  body, there is a proper security, by valves,
from the introduction of blood into them.
  There is  always an ample system of anastomosis, not only
between the branches which  concur to form the right *tnd left
thoracic ducts, but even between the ducts themselves,* so that
if one be occluded  or impeded,  its  circulation  can be turned
into the other, as in  the case  of veins.
* Meckel, Man. D'Anat. tom. ii. p, 581. 
 
BOOK  IX.
                        PART I.

          Of the General Anatomy of the Nervous System.

                     NERVOUS SYSTEM.

  The Essential ingredient of this System is a peculiar animal
matter called JVeurine, the texture of which is so soft, that in
the natural state it has the least possible consistence.   It is,
therefore, protected in a variety of ways; by being enclosed in
bone where it is collected in  large masses, and by being  sur-
rounded  by ligamentous matter where flexure is required.
  The nervous system in man, and other vertebrated  animals,
consists in two portions of dissimilar forms; one is spheroidal,
elongated at its base into a cylindrical process, and is contained
in the cranium and in the spinal canal;  the other is an assem-
blage of  arborescent rays, which  proceed from different  points
of the first portion, to every part of  the body.   The first  por-
tion is the Central  or Internal  part of the nervous system, com-
posed of the Brain and Spinal Marrow,  while  the  radiating
portion is called the External or Peripheral, and consists  in the
Nerves of the brain and spinal marrow.
  The nervous system is remarkable for its symmetry; as it is
universally double, it very seldom  happens that any striking dif-
ference of it on the two sides of the body is manifested, parti-
cularly as regards its Central portion; it is said, however,  that
aberrations, in this respect, are more common in man than in
other mammiferous animals.
  Vol. II.—28 
- 314
NERVOUS SYSTEM.
   The Central Portion of the Nervous System is composed of
 two  kinds  of the  substance  called Neurine,  distinguished by
 their colour and relative situation: one  is improperly enough
 called  Medullary, (Substantia Medullaris,) but as the name is
 now  sanctioned by universal  usage, it is impossible to dispense
 with  it.  The other is called  Cineritious, (Substantia  Cinerea,)
 with, perhaps, sufficient propriety, from its colour.   They are
 both  of a soft pulpy consistence, and constitute the chief mass
 of the brain and spinal marrow: some anatomists have desired
 to add, from some slight distinction of colour, two other sub-
 stances, a yellow and a black, but that seems unnecessary, and
 has not been acknowledged.  These substances differ  from one
 another in regard to their quantity, the medullary being more
 abundant than the cineritious; it is also harder, and receives
 fewer vessels.  But the atoms  of both have the same elementary
 form, that of globules  united by a semi-fluid substance;  the
 shape of  these globules, as well as their size and degree of
 solidity, are  not yet ascertained.*

   The  Medullary Matter, when quite fresh and scraped in par-
 ticular  directions has a filamentous appearance, which may be
 rendered still more distinct by hardening it in alcohol, in boiling
 oil, in a solution of the neutral salts, or in diluted mineral acids.
 If an attempt be then made  to tear it, it will  be immediately
 perceived that the fibres separate in a fixed direction, and in
 no other.   These fibres, when viewed with a microscope, seem
 to consist of fibrillae too fine to admit of any rigid conclusions
 in regard  to  their  size;  and which  are, in some instances, pa-
 rallel, in others, concentric, and in others, diverging or  con-
 verging.!
   The  two substances are  variously placed in different  parts
 of the nervous system: the surface of the cerebrum  and of the
 cerebellum is formed by the cineritious matter, and the interior
principally by medullary ; while the surface of the pons, of the
 crura, and of the spinal marrow, is medullary, and their interior
 cineritious.   Again, in other points, they are intermixed.  The

  * Sir Everard Home, and M. Bauer, Phil. Transactions.  London, An. 1821.
Milne Edwards, Thesis on the Elementary Tissues of Animals. Paris, 1823.
  + See Lessons on Practical Anatomy, by  W. E. Horner, for description ol~
Brain according to Gall and Spurzheim. 
           GENERAL ANATOMY OF THE NERVOUS SYSTEM.        315

medullary matter is always so arranged that it is never inter-
rupted, but forms a continuous whole; while the  cineritious is in
detached masses, and is found wherever the central extremities
of the nerves are implanted,  or where there is an increase of
medullary fibres.  Some anatomists have even supposed that it
existed at the peripheral extremities of the nerves, and particu-
larly in  the rete mucosum of the skin.
  The fibrillse of the medullary tissue  are united by a very fine
and thin cellular substance, which may be seen by tearing them
apart.  This cellular substance is more  condensed  near  the
surface  of the brain, where it is formed into a highly  vascular
membrane, the pia mater, and is continued along the nerves as
a neurileme, or covering to them.
  The  central nervous system  is abundantly supplied with
blood vessels, but lymphatic trunks have not yet been injected
in it

  The Peripheral Portion of the Nervous System or the Nerves,
are formed by parallel anastomosing fasciculi of fibres, percep-
tible to simple inspection,  which may  be  reduced into fibrillar,
and then again into filaments as small as  the thread of a silk
worm. The finest filament is enclosed  in its appropriate sheath,
so that the latter is a tube filled with nervous matter.  The ner-
vous matter is  soluble in an alkali, and in that way may be  re-
moved; the canals may then be filled with quicksilver  or air,
and their  existence demonstrated.  On the other  hand, nitric
or muriatic acid dissolves the sheath,  but hardens the nervous
matter,  and renders it more distinct, so that the finest filaments
are made  obvious.*  In either case it  is evident that the shape
of the nerve is  preserved.   These filaments are supposed to be
precisely the same with the fibres  of  the brain, excepting that
their  sheaths keep them more distinct from one another.

  The Sheath  of the nerves, or the  Neurileme {Neurilemma)
forms a general envelope to the nervous fasciculi, as well as a
particular one  to each fibre, and  is continuous, at its central
extremity, with the pia  mater.  Its canals branch off and unite
again at intervals, forming a  species of reciprocal anastomosis,
* Reil, de Struct, Nerv. 
316
NERVOUS SYSTEM.
sufficiently represented by the plan of the large nervous plex-
uses, as they occur in various parts of the body.   It is the ge-
neral envelope which is obviously continuous with the pia ma-
ter, but the particular sheaths of the finer fibres are lost insen-
sibly, so that these fibres appear  naked in the centre  of the
nerve,  at its central extremity.  The  same destitution of neu-
rilematic covering is observable at the peripheral extremities of
the nerves, wherever the latter can be traced.  The interior of
these canals is traversed by processes, which cross the nervous
matter and sustain it.  From the increase in size, the additional
solidity, and the close adhesion  of the nerves to  the  dura ma-
ter, where they  pass out of their several foramina in the spine
and cranium, there is no doubt that the dura mater contributes
to the  neurileme, though its structure is  altered and made much
less dense.  The best evidence of this is the sheath of the optic
nerve,  and of the spinal nerves.   This opinion, advanced by the
ancients, has been strongly contested  by Haller,* and  by Zinn.f
The tunica  arachnoidea is too fine to admit of any positive opi-
nion about the extent to which it follows the nerves.
   The neurileme  has but little contractility, is solid and diffi-
cult to  tear, and is supposed to  be the  secretory organ of the
medullary substance.
   The  nervous  fasciculi are, moreover, held together by cellu-
lar substance, which has in the  progress of life, a tendency to
the deposite of fat.  This cellular substance, in neuralgic affec-
tions, is subject  to infiltrations and redness, whereby it becomes
hard.   This circumstance has induced  pathologists to consider
the pain as  depending upon its inflammation.^
   The  optic nerve, owing to the size of its canals, furnishes the
best example of structure, and the nerves of the muscles are
next.   There  are, however, some  peculiarities in different
nerves; as the observations of Sir Everard Home have ascer-
tained that the medullary filaments of the optic nerve augment
in numbers and  diminish in volume, from its origin towards its
termination.  The principal  light thrown upon these minute
and interesting  points  of nervous organization, has been de-
rived from the researches of Reil.§

    * Prim. Lin.                      t Memoires de Berlin, 1753.
    X Beclard, Anat. Gen. p. 665*
    § Reil, de Structura Nervorum*  Hal© Saxonum,. 1796, 
           GENERAL ANATOMY OF THE NERVOUS SYSTEM.        317

  In addition to the preceding structure, the nerves present  a
satin-like undulated surface, with small bands that pass some-
what spirally and in  a zigzag direction.   The  latter appear-
ance is illusory, and depends upon the contraction  or shorten-
ing of the nerve when not stretched; its seat is in the neurileme,
and it  accordingly disappears upon extension.
  Some years ago M. M. Prevost and Dumas asserted that they
had found the ultimate filaments of nerves* distributed to mus-
cles, terminating in loops, either by anastomosis  with other fila-
ments  or in a loop of the individual filament.  The observations
of Valentine  and Emmert corroborate those of the preceding
gentlemen.   Valentine has found  the  same arrangement in the
iris and in  the ciliary ligament, in the cochlea of birds, in the
sacs of the teeth, and  in the skin of the frog.   This arrange-
ment does  not,  however, exist as a universal one in the nerves
of sensation  as in the  retina of the vertebrated animals and  of
insects.f
  The nerves abound  in blood vessels; when a  vascular trunk
reaches them, one of its branches ascends and another descends,
and, if successfully injected, the  neurileme is covered  by its ca-
pillary ramifications.   As in the brain, the lymphatics have not
yet been injected,

  There are three  modes by which the nervous  fasciculi  unite
with one another; anastomosis, plexus, and ganglion.  Anasto-
mosis  is the  junction of the filaments, either of the same nerve
or  of  different nerves, and the  examples of it  are very abun-
dant.   Plexus is  an anastomosis on  a larger scale, and occurs
between the  larger fasciculi of the same nerve, or pf different
nerves, whereby a very complete intertexture of their fibres oc-
curs.
  Kronenburg asserts that the primitive fibres of the cerebral
nerves continue separate  up to their ultimate distribution, and
that, in their  apparent union, they only change from one fasci-
culus to another, and that this arrangement prevails not only  in
the plexus, but  in  every part  of the nervous  trunk and its
branches.  This  conclusion he founds upon his observations of

* See General Anatomy of Muscles.     t Muller's Report on N,ervous System,
                           2,8* 
318
NERVOUS SYSTEM.
the brachial plexus in mammalia, and of the lumbar plexus  in
the frog.*
  Ganglions are knots which occur in the course of nerves,
whereby they  have, for the time,  a great  augmentation of vo-
lume.  The ganglions have  a great variety of form  and size;
they are parabolic, circular, crescentic and so on; and, in their
general appearance, hardness, and colour, resemble somewhat
lymphatic glands.   Their structure is intricate, and as yet ra-
ther unsettled.   When submitted to maceration, they are re-
solved into two kinds of substance; one is  filamentous and  con-
tinuous with the nerves, adhering to the ganglion; and the other
is gelatinous and of a reddish  ash  colour.  The filaments,  in
penetrating the ganglions are deprived of their neurileme, which
is continued into a sort of capsule that surrounds the ganglions.
They pass uninterruptedly through the ganglion, and, therefore,
continue the several nervous cords into one another;  but, in a
complicated way.  The nature of the gelatinous substance is not
fully ascertained;  by some, and  Scarpa  among others, it  is
thought to be fat. The ganglions, like other parts of the nervous
system, are very vascular.

  The Ganglions are said to be simple and compound; the first
is where a single nerve produces the ganglion, and the second
where the filaments of two or more nerves concur to form  it.
The simple ganglions are invariable in their form  and situa-
tion, and belong to the spinal marrow, being formed upon the
posterior  fasciculi  alone: this fact  was first pointed  out by
Haase,| and has been subsequently confirmed by the observa-
tions  of Scarpa and of Prochaska, and by the admission  of
anatomists generally.  The  exterior envelope  is continuous
with the dura  mater, and the internal with the  pia mater, from
whence they have more firmness than other ganglions.   The
compound ganglions are found at divers stations about the
body.

   The attention of the profession has been  much directed lat-
terly to the microscopicaUobservations of Professor Ehrenberg,.

  * Muller's Report on Nervous System, p. 232,. for the year 1836..
  \ De Gangliis Nervorum.  Leipsick, 1772. 
           GENERAL ANATOMY OF THE NERVOUS SYSTEM.        319

of Berlin, on the structure of the Nervous System.*   The fol-
lowing is a summary of his doctrines on this subject.  The in-
strument used being a microscope of Chevalier of Paris, aug-
mented in power by Pistor and  Schiek, of Berlin.
  The organic structure  of the Encephalon, the Spinal Cord,
and the Nerves, presents:
  1. A set of straight tubes, like a  string of mock pearl beads,
and whose spheroidal enlargements are  kept apart by an inter-
mediate canal.   These nodulated tubes he calls varicose, from
their mechanical conformation or resemblance to varicose veins;
he  also calls them  jointed or articulated from  their shape.
These are parallel to one another, cross  occasionally, are never
seen to anastomose, and are like filaments: they contain  a pe-
culiar matter, designated  the Nervous fluid, (Liquor Nervosus
of Haller,) and are confined chiefly to the white or medullary
portion of the Encephalon and  Spinal Marrow.  They are of a
milky colour.
  2.  A set of filamentous bodies, which are hollow or tubular,
of a simple cylindrical shape, that  is, not having the irregular
surface or nodes of the preceding.  They are uniform, and ge-
nerally larger than the nodulated, though the latter are in  places
continued into  the former.  They contain a white viscid fluid,
to which  he gives the name of Medullary, and which  is less
transparent than the Nervous.   These tubes  are the one hun-
dred and twenty-ninth of  a line thick in the  middle;  they are
elementary, are not surrounded individually by a neurileme,
are collected into  fasciculi, which,  in that  state, have  a  neuri-
leme, and these fasciculi are grouped into larger chords or nerves
proper.  The elementary tubes, though  they, pass from one fas-
ciculus to another, do not discharge or empty into one  another,
their anastomosis being merely  one of adhesion.  These  cylin-
drical tubes exist  chiefly in the nerves.
  3.  A granulated matter, some of  the grains of which are
very  fine  and some coarser,  being disseminated through th&
others.
  This is confined to the cineritious substance of the convolu-

  *  Memoir of 1833-1836 to the Academy of Sciences of Berlin, translated by
David Craigie, M. D.  Edin. Med. and Surg. Journ. Oct. 1837 : copied into Es-.
Bays on Physiology, Phila.. 1838. 
320
NERVOUS SYSTEM.
tions of the cerebrum, to the laminated surface  of the cerebel-
lum, and the cineritious part of the Spinal Marrow.
  4. The articulated tubes present patulous ends to this granu-
lated  collection, which ends are  fitted for the  purpose of re-
ceiving them directly, and for the distillation of the Nervous
fluid,  (Liquor Nervosus.)
  5. The cylindrical tubes of the motiferous nerves are imme-
diate  continuations of the nodulated tubes.  This is perceptible
in the nerves of the medulla spinalis and of the cerebrum, ex-
cepting the Olfactory, the Optic, and the Auditory Nerves, which
are unchanged nodulated tubes.
  6. Professor Ehrenberg's observations on living nerves  have
not yet exhibited the circulation of a nervous fluid in them, but
he declares neither for nor against it.
  7. The Ganglions, or Nervous knots, consist of the articulated
tubes alone, or mixed with the cylindrical tubes.   They have
also a very fine network  of blood-vessels, with nervous gra-
nules  intermixed with them.  They are, in fact, comparable to
brains.
  In the present state of microscopical anatomy it  is impossi-
ble  to tell whether the  foregoing  is a history of delusions or a
narrative of fact.   Every  im-provement  of the  microscope,
since  its first discovery,  has, in subverting preceding opinions,
claimed for itself infallibility;  yet there has been, at no  period,
uniformity in the results of experienced observers.  We have,
in the present  instance, according  to Ehrenberg, Professors
Muller and Wagner approving and confirming by their testi-
mony; and Professors Remack, Treviranus,* Krause, and Volk-
man, objecting.   Such  an instrument  as a highly magnifying
microscope,  in  establishing new  relations of vision, leaves  us
destitute of those countertests which are indispensable to infal-
libility; its indications  may be right, but they always  present
much room for doubt.

  * Progress of the Anatomy and Physiology of the Nervous System, during
the year 1836, by Professor Muller, of Berlin, (copied into Essays on Physiology
and Hygiene, Phila. 1S38,) who does not himself seem to be an ardent convert to
the views of Professor Ehrenberg; as he says, "Whether or  not the minute ele-
mentary structure of the nerves is known, must still remain  a matter of doubt "
p. 231 
GENERAL ANATOMY OF THE NERVOUS SYSTEM.
321
   The Nervous system is the seat of intelligence, and also ex-
 tends  its physical influence  to every part of the body.   Both
 the one and the other qualities reside in its central portion; the
 first in the brain, and the second in the spinal marrow.  When
 the communication between  the brain and the spinal marrow is
 interrupted by an accident, or in  an experiment, the difference
 between the influence of the two is  strongly marked:* the in-
 fluence of the brain seeming to be entirely intellectual, so that
 an animal will even bear its  removal without immediate death;
 while  the influence of the spinal marrow is so indispensable to
 life, that its destruction is followed by instantaneous  and perfect
 death.t   Under common healthful circumstances, however, the
 two seem to exercise a mixed influence on all parts of the body;
 as, for example, upon the reception  of distressing intelligence,
 the stomach  ejects  its contents, or refuses to receive  more;
 alarming intelligence causes the heart to flutter and to palpi-
 tate, and both the bladder and the intestines to evacuate  their
 contents.  On the  contrary, a proper degree of corporeal ex-
 ertion  strengthens the  intellectual operations, while its excess
 debilitates them.  That these several  nervous influences are
 seated in the central part of  the nervous  system, seems proved
 by the fact, that where there has been  a  congenital deficiency
 of all the limbs, or an accidental one, which, of course, removes
 a very considerable portion of the peripheral part of the  ner-
 vous system,  animal life and  the intellectual operations have
 still gone on vigorously.
   The following are some of the physical functions over which
 the nervous system seems to  preside.
   Digestion; the whole alimentary canal, from the mouth to the
anus, is under  its influence: first  of  all in mastication, then in
swallowing, afterwards in digestion and the absorption of chyle,
and, finally, in the passing of the effete  matter out of the body.
It  has  been sufficiently proved, by the  experiments of several
physiologists,  that the section  of the par vagum destroys the
faculty of digestion.
   Respiration; the mechanical act of this process, that by which

  * Legallois on  the Principle of Life.
  ■J- Observ. and Exper. on the Nervous System, by W. E. Horner.  See Chap-
man's Med. and Phys. Journal, vol. i. p. 285. 
322
NERVOUS SYSTEM.
the cavity of the thorax is enlarged so as to admit of the intro-
duction of air, evidently depends upon the phrenic and the inj
tercostal nerves.   If the nerves which  supply the structure of
the lungs be alone  intercepted, as the par vagum, either by liga-
ture or section, the changes on the bjood produced by respiration
cease,  and the animal dies.
   Secretion, exhalation, absorption, and animal  heat, seem also
to be dependent upon the integrity  and  the activity of nervous
influence.   The action of the heart, sensation and voluntary mo-
tion, are in the same predicament.
   The manner in  which these several kinds  of innervation is
produced, is unintelligible.   One has supposed it to consist in a
vibration of the elementary  fibres of the nerves; another in an
agitation of their elastic globules; another in the transmission of
an imponderable fluid, as ether, magnetism, electricity, and Gal-
vanism.  Reil  has proposed,  on this subject, what has  been
termed a chemico-vital hypothesis: according  to him, the ge-
neral action of parts depends upon  their form  and composition;
consequently, when the two  latter vary, the first does also.  M.
Beclard* inclines to the opinion, that "the nervous system is
the elaborator and conductor of an imponderable  agent;  and,
like electricity or magnetism, that  by it we can explain  all the
phenomena  of innervation:—The relation between the benumb-
ing influence of electric fish and Galvanic phenomena on one
part, and ordinary nervous action on the other;—The practica-
bility  of  causing  Galvanic phenomena  by the  nerves and
muscles alone;—The  possibility of producing muscular con-
traction, the chymifiant action of the stomach, the respiratory
action of the lung, &c, in  substituting a Galvanic for a ner-
vous influence;—The  existence  of a nervous atmosphere, ac-
ting at a distance  around the nerves and muscles, and between
the ends of  divided nerves;—The  wrinkling of  muscular fibres
in contraction, and the relation of  the finest transverse nervous
fibres with those wrinkles, are phenomena of innervation which
nearly approach certain electro-magnetical ones."
   This subtile fluid, according to M. Beclard, seems to be formed
every  where, but  principally in places where there is much
vascularity  along with the ash-coloured substance.   It impreg-
* Anat. Gen. 
           GENERAL ANATOMY OF THE NERVOUS SYSTEM.        323

nates all the humours and organs.   The blood seems to be es-
pecially endowed with it, and owes to it the  properties which
distinguish it during life.   In consequence  of  which, life is es-
sentially connected to  the reciprocal action of the blood upon
the nervous substance, and of the nervous substance upon the
blood.*
   Mr. Charles Bell, of London, has lately  presented, in a  very
interesting light, certain functions  of the nervous  system :f by
his researches it appears, that besides the nerves of vision,
smell, and hearing, there are four other systems, having differ-
ent functions, and extended through  the whole  frame.   Those
of Sensation;  of Voluntary Motion;  of Respiratory Motion;
and nerves, which  give unity to the  body in  harmonizing the
functions of nutrition, growth, and decay,  or  whatever else is
indispensable to animal existence.^
   According to this theory, the several filaments of a nerve ex-
ercise one or the other function, but only the one; these dissimilar
filaments being bound up  in the same  fasciculus, constitute  a
nerve or fascis, and they never exchange power with one ano-
ther ;  their anatomical differences, however, are such, as not to
make obvious  one  kind of filaments from the others.   Several
columns of nervous matter form the spinal marrow, six in all,
three on each side; the anterior for voluntary motion,  the pos-
terior  for sensation, and the middle for respiration;  and it is
probable that still more  may be found out.  The first and the
third  ascend into  the brain, and  the  middle  stops short in the
medulla oblongata; hence, the  function of respiration  goes on
so long as  the  medulla  oblongata remains entire.  These few
principles, supported by several experiments, have enabled Mr.

   * M. Rolando (Saggio sulla vera struttura del cervello, e sopra le funzioni del
sistema nervoso, 1809, Beclard, p. 622,) has been so much taken with the Gal-
vanic manifestations of the nervous system,  that in the laminated arrangement of
the cerebellum, he has only seen a modification of the Voltaic pile.  In the con-
volutions of the cerebrum, he, no doubt, would have recognised on acquaintance,
with that powerful instrument; the Spiral  Calorimotor of  Professor Hare  of thi
University.
   * Exposition of the Natural System of the Nerves of the  Human Body. Philad.
1825.
   $ For a comprehensive  eclectic view of the present state of opinions on the
physiology of the Nervous System, see Human Physiology by Robley Dungli-
son, M. D. Professor, &c.  Philad. 1838. 
324
NERVOUS  SYSTEM.
 Bell to bring forward a system of no small importance, on the
 anatomy and  physiology of the nervous system.*
   The development of the nervous system is amongst the ear-
 liest processes in the distinct evolution  of the  fcetal  organs.-)-
 At the end of the first month, when  the head  is a mere swell-
 ing of one end of the small maggot-like being, the brain and
 the spinal  marrow are not by any means distinct, but the parts
 being  transparent, a  limpid fluid  holds their place.   About the
 fifth or sixth week, the embryo having acquired a length of five
 or  six  lines, the rudiments of the  brain appear as vesicles con-
 taining a whitish and almost diaphanous fluid, while the spinal
 marrow represents a long canal containing the same, and com-
 municating with the cerebral vesicles.
   In the early part of the third  month, the brain  and  spinal
 marrow show very distinctly the  rudiments of the  several ca-
 vities,  elevations,  and fasciculi, which mark  their subsequent
 mechanical arrangement of surface;  and from this period it is
 no  longer   difficult to trace  the successive  development  of
each part to the degree of perfection which it has at the time  of
 birth.
  From the many observations made by Tiedemann on  these
points, he has  deduced the conclusion, that the brain is produced
by  the superior part of the spinal marrow; that is to say, by the
medulla oblongata, which grows and  is developed for  the pur-
pose.   That this is proved, in  the extension  upwards and for-
wards  of the two principal fasciculi of the spinal marrow, and
by  a canal which is found  in the  spinal-marrow of the foetus,
being extended to the fourth, and even  to the third ventricle;
also, by the cerebellum proceeding evidently from the  medulla
spinalis, since  its two crura may be traced growing from it, and
subsequently uniting over the fourth ventricle, so as to form the
especial structure of  the  cerebellum; also, by  the tubercula
quadrigemina  being derived from the corpora olivaria of the

  •  The same subject has been taken up, in an inaugural thesis,  by a zealous
and intelligent graduate of  the University; and, by a series of ingenious experi-
ments, seems to have been  generally proved and illustrated.  Chapman's Med.
andPhys. Journal, 1823, vol. vi. p. 240. Remarks on some of the Nervous Func-
tions, by J. P. Hopkinson, M. D.
  f Anat. du Cerveau, par F. Tiedemann, traduit par Jourdan, Paris, 1823.
Anat. Comp. du Cerveau, par E. R. A. Serres, Paris, 1824. 
           GENERAL ANATOMY OF THE NERVOUS SYSTEM.       325

medulla oblongata, and by the thalami and the corpora striata
proceeding from the corpora pyramidalia, and, finally, forming
the hemispheres of the cerebrum.
  In addition to the preceding proofs, comparative  anatomy
furnishes other illustrations. The brain becomes more and more
complex as one ascends from fish to reptiles, from the latter  to
birds, and then to mammiferous animals.  The spinal marrow
is very voluminous in the inferior animals, while the brain only
forms an appendix to it; whereas, if the spinal marrow were an
appendix to the brain, we ought to find the last of a prior for-
mation in foetuses, and  also in a perfect state in the lower ani-
mals, before a medulla spinalis could be observed.*
  The exploration of the anatomy of the Nervous System with
the microscope  has  latterly become a very favourite pursuit,
with what advantage to science remains to be settled.  For an
exposition of the general results of such labours, see Progress
of the Anatomy and Physiology of the Nervous System, during
the year 1836, by Professor  Muller of Berlin.  These results
present very contradictory and incompatible views, the conclu-
sions of one observer being the antagonists of those of another.
To which side the credit of truth  is to be attached, time  must
determine.  We  have to remark that this paper bears the stamp
of most others which have been presented on the  nervous sys-
tem for some years, that of inconclusiveness and great doubt on
its professed objects.
                  * Tiedemann, loc, cit. p, 157,
Vol. II.—29 
 
BOOK  IX.
                        PART II.

On the Special Anatomy of the Central portion of the Nervous System.


                     CHAPTER  I.

      OF THE SPINAL MARROW AND ITS MEMBRANES.

  The Spinal Marrow,  (Medulla Spinalis) though commonly
described after the brain, as a continuation or appendage of it,
has precedence,  as seen, both in the period of its formation in
the embryo, and in its importance to  the functions of the ani-
mal system; it will, consequently, be proper to give it that prio-
rity in description to which its natural rank entitles it.
               SECT. I.—OF THE SPINAL MARROW.

  It is placed within the vertebral cavity, and extends from the
first vertebra of the neck to the first or second vertebra of the
loins, inclusively.   It is surrounded  by  three membranes, of
which the Dura Mater is external, the Pia Mater internal, and
the Tunica Arachnoidea, between the other two.  Its general
form is cylindrical, yet it has slightly the appearance of being
flattened both behind and before.  It departs also from the strict
cylindrical shape, by being  enlarged or  swollen at particular
points.  One of these enlargements occurs in the neck, where
the spinal canal is formed by the  five lower cervical vertebree,
and the roots of the axillary plexus of nerves are given off.  The 
328
NERVOUS SYSTEM.
 enlargement is in the transverse direction or axis of the spinal
 marrow, but not so much  in its thickness, and terminates gra-
 dually both above and below.   The medulla spinalis afterwards
 continues small, with very slight undulations or nodosities, until
 within three or four inches of its lower extremity, when it again
 enlarges.  The enlargement here, though sufficiently obvious,
 is not equal in actual magnitude to that in the neck, and is the
 place from which all the lumbar nerves and the three superior
 sacral proceed.  It is then brought gradually to a point some-
 what blunted, which most commonly does not  descend below
 the first lumbar vertebra.   The point  is, in some rare cases,
 bifurcated,  and by a  transverse  fissure  converted into a tu-
 bercle.
   The spinal marrow, besides  terminating so much above the
 lower end of the spinal canal,  is much  smaller in  its diameter,
 even with the addition of its membranes, than the canal.  This
 circumstance prevails, especially in the neck, and in the loins,
 where much motion is experienced; and, consequently, a provi-
 sion is thus made  against any injury to  it  from pressure.*

   The Medulla Spinalis is marked off, longitudinally, into  two
 symmetrical parts, by one  fissure in  front and another  behind,
 both of which extend its whole length, and are placed exactly
 in its middle. The contiguous edges or surfaces of each of these
 fissures adhere so, that it requires a slight maceration or dissec-
 tion  to render them evident.  The posterior fissure is decidedly
 deeper, especially  at its upper  part, than  the anterior: but the
 latter, in return, is somewhat broader.   The difference in depth,
 however, is unimportant, as subjects are frequently met with in
 which it  is not appreciable.
   Moreover, on each side of the medulla  spinalis there is a la-
 teral fissure.   It is not precisely in the  middle, but somewhat
 posterior, and pentrates inwards and forwards.   In many in-
 stances it is merely a simple superficial depression, much  less
 deep than either of the former.   It does not run the whole
length of the medulla spinalis, but terminates somewhere in the
 upper part of its thoracic portion by joining with its fellow af-

  * The Spinal Marrow at the third mouth of the embryo extends to the end of
the coccyx; it then suddenly contracts to the second lumbar vertebra. The coc-
 cyx ia contemporaneously reduced from  seven to four  pieees.  Serres. 
                       SPINAL MARROW.                    329

ter  having converged  regularly towards it.*  The  different
opinions of anatomists on the existence of this fissure may be
accounted for by its being readily found in early life, while it
is obliterated or very indistinct in old age.  This lateral fissure
should be  carefully distinguished from two others, one before
and the other behind  it, which extend the whole length of the
medulla  spinalis, and consist in a  series of little depressions,
running into each other and transmitting the filaments which
form the roots of the spinal nerves.  The posterior, of the last
named lateral fissures,  is deeper than  the anterior, and pene-
trates in the same  direction with  the lateral  fissure first men-
tioned;  it also, in like manner, joins its fellow, but only after
having proceeded to within a few lines of the inferior end of the
medulla spinalis.
  The substance of the spinal marrow being of two  kinds, ci-
neritious and medullary, the order  of their position is  reversed
from what occurs in the brain; for the cineritious is included or
enveloped by the other.  On making a  transverse section, the
cineritious  will  be  found much less abundant  than the  other,
and consisting of a  thin transverse lamina in or near the centre
of the medulla:  this part is joined at either end  to a portion
somewhat crescentic, whose concavity is outwards, and the con-
vexity inwards.  The transverse   part  does  not  run into the
middle of the crescent, but somewhat anterior to the middle, so
that the anterior horn  is shorter  than  the other, and is also
thicker  and obviously more obtuse.  The cineritious or grayish
substance is more abundant at the lower part of the medulla
spinalis  than it is above.  In the foetus,  at  the end of gestation,
it predominates  below, occasionally, to  the entire exclusion of
the other.  The  medullary  or white substance  is more abundant
laterally than elsewhere, and has its two symmetrical sides joined
together by a thin lamina at the bottom of the anterior and of
the posterior fissure.
  Each half or symmetrical side of the medulla spinalis is itself
divided into two chords, marked off from each other by the pos-
terior horn of the cineritious crescent, and by the first described
lateral fissure.   Of these chords the anterior is, consequently,
much the larger; it is also longer and forms the inferior extre-

                   * Meckel, Manuel D'Anatomie,
                            29* 
330                     NERVOUS SYSTEM.

mity or the point of the medulla spinalis.   The posterior chord,
though so much smaller and narrower than the anterior, is it-
self subdivided into two, by a slight but well marked split; of
these two last chords, the one next to the posterior middle fissure
of the medulla is smaller than the other.   These arrangements,
according to Meckel, are much  more obvious in the early life
of the human subject, than afterwards, and are particularly con-
spicuous in the brute creation.
   The thin white laminae  by which the two sides of the spinal
marrow adhere to each other  at the  bottom of the middle fis-
sures, are called,  by modern anatomists, Anterior and Posterior
Commissures.  Their precise arrangement is not yet fully ascer-
tained, but it is stated by Gall and Spurzheim,* that the Anteri-
or Commissure is  formed by transverse fibres or filaments, which
adhere to one another  from the opposite sides  like a suture, or
after a serrated fashion; whereas, the Posterior Commissure is
 formed by a band of longitudinal fibres.   There is  also another
 Commissure, called Middle or Cortical,  from  its  position, and
 from its being formed out of the transverse  part of the grayish
 or cineritiou** substance.
    The chords which form each  half of the medulla are differ-
 ently disposed: the  posterior continues on the side to which it
 specially belongs, while the anterior having got within the cir-
 cumferrnce of the first cervical vertebra,  crosses over to the op-
 posite side by decussating with its fellow.   This decussation oc-
 cupies the  space of  four or five lines, and interrupts, for that
 distance, the middle fissure in front of the medulla.  It  is not
 effected by the chords passing in mass from one side to the other,
 but each chord sends  off four or  five fasicuii, which are inter-
 woven with their congeners,  like the fingers of the two hands
 when interlocked obliquely.  It is to be observed that the whole
 mass of the anterior chords is  not subjected to such distribution;
 for the fasciculi just  described come from their  anterior and
 from their  posterior faces, while  the intermediate part  is per-
  mitted to pursue its course straight upwards.   This decussation,
  upon  which so much  interesting physiological speculation de-
  pends though  known for the last century, and  spoken of by
  Mistichclli  and  Petit, lias been strangely overlooked by many

      * llecherches sur le Syst. Nerv. ct sur celui du Cerveau.   Pari?, 1809. 
SPINAL MARROW.
331
anatomists, and  even positively denied by  some.  There  are
other places where the fasciculi of the spinal marrow seem to
cross  from one side to the other, but the fact is not yet verified
sufficiently.
  The existence of canals in the spinal marrow has been from
time to time announced ;* though authors differ much in the ac-
counts of their position and extent.   When such an appearance
is presented, it is supposed,  by some, to be  either the result of
disease or of accident, with the exception of a small one of eight
or nine lines long, which communicates at  one  end  with  the
fourth ventricle, and is shut up at the other.t
  Valentine asserts that the primitive fibres of the nerves, which
join the spinal marrow, do not terminate  there, but pass on to
the brain.J  In the spinal marrow of a child, it is very easy to
divide it by tearing into threads, running its whole length; these
threads do not seem to have any determinate number, but to be
regulated by the healthy consistence of the spinal marrow, and
the patience with  which the process is  pursued. If a spinal
marrow has  been macerated for some years in spirits, it may
be  broken or split up into  radii,  from the centre to the cir-
cumference, like  a tree, and  these sections divided into thin,
short, flat laminae adhering to, or anastomosing with such as are
contiguous to  them.  Muller found a similar  arrangement in the
spinal marrow of the  Petromyzon Marinus,  though  he  has
never seen it in any other animal.

   The Spinal Marrow sends out from its sides thirty pairs of
nerves, which, like the vertebrae, are  arranged  into  cervical,
dorsal or thoracic, lumbar and sacral.  Of these there are eight
cervical, one  of which, from its escaping between the occiput
and the first vertebra, is most usually designated as sub-occipital,
and, therefore, the number of the cervical nerves is reduced to
the same with that of the vertebras, to wit,  seven.  There  are
twelve pairs of dorsal nerves, five of lumbar, and five of sacral.
Occasionally, there is a  sixth sacral nerve on each side, which
augments the number of spinal nerves to thirty-one pairs.
   Every spinal  nerve is formed from two  roots on the same
             * Gall, Portal, Morgagni.
             t Meckel, p. 605, vol. ii. Bichat, vol. iii. p. 128,
             t Muller's Report on Nervous System. 
332
NERVOUS SYSTEM.
level, one before and the other behind, and each root consists in
several fasciculi of nervous matter.  The front root arises from
the anterior chord of the medulla spinalis, and the other from
the posterior chord.  The posterior root is larger than the an-
terior, but has fewer fasciculi in  its composition, and is not so
filamentous.  The two roots are kept asunder by the Ligamen-
tum Denticulatum.  The fasciculi of each are slightly connected
by a loose delicate  cellular substance, and as they are  about
penetrating the dura mater, each fasciculus collects into a sin-
gle chord, which passes the dura mater through its appropriate
foramen.  In this way the anterior and  posterior roots are kept
distinct till they have got to the outside of the membrane men-
tioned; but the foramina, through which  they pass, border close-
ly upon one another.  The posterior root, then forms a ganglion
of a round or oval shape; from whose external extremity there
proceeds a single nervous trunk, which is joined immediately
at its commencement by  the anterior root.
  With the exception of  the ganglions of the sacrum, which
are in the spinal cavity of that bone, these bodies are  placed in
the intervertebral foramina.   The  size  of the ganglion  is not
proportionate to that of the nerve from  which it proceeds;  for
some of the dorsal ganglions are  the largest, while those of the
sacrum are smaller than  any others.
  The two nerves of the  same pair, though generally symme-
trical, or precisely  resembling,  are not invariably so; some-
times one is  placed  higher than another, and  the number of the
fasciculi may be greater or smaller.  The roots of the nerves
are much nearer, or cluster more at the extremities of the spi-
nal marrow, than its middle.

  The Cervical Pairs of Nerves  are nearly horizontal in their
course from the medulla  spinalis to the foramina in  the dura
mater.  The first one, or the sub-occipital, is strictly so;  the
others incline very gradually more and more downwards.  They
have, therefore, but a very short passage before they reach the
intervertebral foramina.   Their roots are so pyramidal, that the
bases nearly touch each other, and, for  the most part, are con-
nected by an anastomosing filament, which goes from the upper
margin of the nerve below to the lower margin of the nerve above.
These anastomoses are found connecting the upper  with  the 
MEMERANES OF THE SPINAL MARROW.
333
 lower fasciculi, both on the anterior and posterior chords of the
 medulla, but more uniformly as regards the latter.   Modifica-
 tions of this arrangement, which it  is unnecessary to specify,
 are met with in different subjects.

   The Dorsal, or Thoracic Pairs, are much inferior in size to
 any other  nerves, except  the  inferior sacral.  Anastomosing
 filaments do not generally prevail, yet they are found occasion-
 ally,  as in  the neck, upon the two or three upper pairs.   The
 first one has the broad pyramidal or triangular root of a cer-
 vical nerve, and resembles it also in volume.  The second is
 the smallest of any; they then go  on increasing in size to  the
 lowest, but not in uniform gradation.  They are successively
 more oblique, and consequently longer from their bases to their
 passage through the dura mater.

   The Lumbar and the Sacral Pairs arise closely upon each
 other, indeed in absolute contact successively, from the lower
 end of the  medulla spinalis, and form a cluster of filaments re-
 sembling the tail of a  horse, hence it is  called Cauda Equina.
 As their place of origin is within the precincts of the first lum-
 bar vertebra and the two or three last dorsaL. they all observe
 a very oblique course in their descent to the vertebral forami-
 na, and the lower ones are almost vertical.  Notwithstanding
 they  are in contact, and adhere by a loose cellular substance,
 yet there are no anastomosing filaments between  the  adjacent
 roots.  From the sacral  ganglions  presenting the peculiarity
 of being situated in the spinal  cavity of the sacrum, instead of
 in the foramina, the single nerve formed from the  ganglion and
 the anterior fasciculus, has to proceed a distance more or less
 considerable in the spinal  cavity before it can escape from it.


         SECT. II.—MEMBRANES OF THE SPINAL MARROW.

         Of the Dura Mater of the Medulla Spinalis.

  This membrane, forming the exterior envelope  of the spinal
marrow, extends from one end of the spinal canal to the other,
being continuous above with the dura mater of the brain, and 
334
NERVOUS SYSTEM.
 terminating below in a cul-de-sac, or closed extremity.  It does
 not adhere to the surface  of the spinal  canal, but lies loosely
 attached to it, with the exception of the first cervical vertebra,
 to which it is closely fastened.   Between it, and the ligaments
 and periosteum on this surface of the bones of  the spine, is a
 long, loose, and spare cellular substance, generally somewhat
 watery, and containing in  the  lumbar  and  sacral regions, a
 reddish adipose matter.
   This membrane is so much larger than the medulla, that  it
 invests it very loosely and always presents a collapsed appear-
 ance.   Where the nerves penetrate, it furnishes to each one, a
 sheath as far as the  intervertebral  foramen.   Having reached
 the  intervertebral foramen, the sheath then enlarges so as to
 enclose the ganglion, adheres by cellular substance to the con-
 tiguous periosteum, and is then insensibly lost in the  tunics of
 the  nervous trunk.  Those sheaths are  longer  for the cauda
 equina  than elsewhere, and, of course, observe  the same suc-
 cessive obliquity with the nerves  to which they belong.
   The internal surface of the dura mater is smooth and shining,
 which is probably owing to the tunica arachnoidea being  re-
 flected over it.
   This membrane has a fibrous texture, and with inconsidera-
 ble exceptions, is like that of the brain.


     Of the Tunica Arachnoidea of the Medulla Spinalis.

   This membrane is next to the dura  mater, and is easily dis-
 tinguished by its extreme delicacy, thinness, and almost perfect
 transparency.   It is  destitute of  red  blood vessels.  It forms
 a  complete envelope for the medulla  spinalis, and adheres  to
 the Pia Mater very loosely by means of long, slender, and scat-
 tered filaments of cellular  substance.  If the dura mater be
 slit up its whole  length  before and behind, and a blow-pipe
 be introduced at one end  of  the  medulla, between  the pia
 mater and the arachnoidea; inflation  will cause  the latter  to
 rise, and to present itself as a long  capacious  tube, detachinc
 on each side processes which surround the roots  of the nerved
 These  processes having reached the  points where  the nerves
penetrate the dura mater, are ihen reflected upon its internal 
MEMBRANES OF THE SPINAL MARROW.
335
face, being spread over it, and thus giving it the glistening ap-
pearance.  The processes enclosing the fasciculi of the spinal
nerves, are particularly conspicuous about the Cauda Equina.


          Of the Pia Mater of the Medulla Spinalis,

  This third envelope of the spinal marrow forms  also a com-
plete investment of the latter, and adheres  very closely to it.
Its external face is smooth, and is in contact with the arach-
noidea, from  which  it may be  readily  separated  by inflating
the latter.  But from the middle of its internal face both ante-
riorly  and  posteriorly, a process  or  partition penetrates into
the middle fissures of the medulla  spinalis, and reaches to their
bottoms.  From  these partitions  there  proceeds a great num-
ber of small vascular canals, that pass in various directions
through the medulla, and  anastomose freely with  each other.
This arrangement is rendered sufficiently obvious  by injecting
and tben destroying the medulla in an alkaline solution;  or if
the medulla be hardened by neutral salts or acids,  it splits into
many longitudinal radiated laminae, divisible into chords, where-
by the arrangement is made equally manifest.   A fact  of some
consequence is thus established, to wit,  the similitude  between
the structure of a nerve and of the medulla spinalis.
  At the inferior  end of the medulla  the pia mater becomes a
single  chord, which is continued among the cluster of nerves
constituting the  Cauda Equina to the  lower  end  of  the  tube
formed by the dura mater, and there it joins with the latter.
As a membrane, the pia mater is mueh more complete  than
the corresponding one of the brain, has more strength, but is not
so vascular.   Its thickness iucreases  in its descent.   It is of a
yellowish-white  colour.   It  seems to hold the medulla some-
what  in a state of compression, for when  a puncture is made
through it, the medullary substance protrudes like a hernia.
It goes from  the medulla to the fasciculi oT nerves and forms
their neurileme or sheath.
   The pia mater seems to impart great elasticity to the spinal
marrow, for when the latter is  detached from the  spine by the
severance of its nerves, it contracts suddenly and forcibly to
the amount of from one to two inches. 
336
NERVOUS SYSTEM.
                  Of the Ligamenta Denticula.

  These bodies are narrow semi-transparent  bands, and very
thin, which are placed one on either side of the medulla spina-
lis,  between the pia mater and the tunica arachnoidea.   They
commence at  the occipital foramen, and descending between
the anterior and the  posterior fasciculi of  the  roots  of the
nerves, terminate somewhat ahove the inferior extremity of the
medulla spinalis.
  Each one is, at its commencement, in front of the accessory
nerve, and in descending  is rather nearer to the posterior than
to the  anterior fasciculi.   By its internal  margin it adheres
with uniformity to  the pia mater, but  the external margin has
a very  different arrangement; for it sends off at intervals from
twelve  to twenty-four serrated or denticulated processes, which
for the  most part are placed  between the fasciculi of cervical
and of dorsal nerves.   The extremities of these teeth are small,
rounded, and  strong, are  surrounded by the arachnoidea, and
adhere  very firmly to the dura mater,  being  pointed  down-
wards.' The position and connexions of each ligamentum den-
ticulatum are such, as to  make it serve  as a fastening; which
use is additionally  indicated by its  fibrous texture, and  by the
necessity that the medulla has for such fastening, in considera-
tion of  its being so deficient in filling up  the vertebral canal.*
  It is  taught by many anatomists, that the ligamenta denticu-
lata, from the opposite sides, join at the   lower end of the spi-
nal marrow to form  the  single cylindrical chord, just  men-
tioned,  that passes thence  to the lower end of the spinal cavity,
and has been  described as an emanation from the pia  mater.
I am, however, induced to think with Meckel and others, that
general analogy is  in favour of the latter.

  * An opinion has been advanced by Professor Pancoast that the pia mater of
the elephant, of the bullock, and of man, forms by its duplicature the ligamentum
denticulatum.  The specimen of  the former which I have seen in his possession
affords strong indications of that  arrangement: at the same time, in examining
its point of origin in man from the dura mater at the foramen magnum, its dis-
tinctly fasciculated and  tendinous character there, is in opposition to this con-
clusion : the fissures which separate  it along  its internal margin  from the pia
mater are also not favourable to this idea, which in other respects is plausible
and ingenious.—Wistar's Anat. Vol. 2, p. 513. Phila. 1839. 
BLOOD VESSELS OF THE MEDULLA SPINALIS.
337
  SECT. III.--OF THE BLOOD VESSELS OF THE MEDULLA SPINALIS.

  The Arteries of the Spinal Marrow are derived from  the
Vertebral, Intercostal, Lumbar, and Sacral Arteries.

  1. The Posterior Spinal Artery (Arteria Spinalis Posterior)
is the lowest branch of the vertebral, given off in the cavity of
the  cranium.  It  reaches,  soon  after its  origin,  the posterior
face of the Medulla Spinalis, and runs to the lower extremity
of the latter, on the side of its posterior  fissure.  Its course is
parallel with  its fellow, and very serpentine.   In its descent it
is continually re-enforced by small branches which get into
the spinal cavity  through each of the intervertebral foramina,
they being twigs from the Vertebral Intercostal, and Lumbar
Arteries.

  2. The Anterior Spinal Artery  (Arteria  Spinalis Anterior)
arises  above the last from-the vertebral.   Shortly after  its  ori-
gin it  unites with its  fellow into  a  common  trunk, which  de-
scends along the  anterior fissure of the medulla spinalis, but is
subject to interruptions.   It also is  re-enforced by  twigs from
the same arteries  that pass into the spinal cavity through the in-
tervertebral foramina.  In its whole courseit sends off branches
from each side to the medulla spinalis.

  The Cauda Equina is supplied  by arteries  from the Lumbar
and from the Sacral Arteries, which reach it through the fora-
mina,  between the vertebras and  in the sacrum.

  The Veins of the Spinal Marrow are very abundant. A large
one on each side  of the middle line, called the Sinus Columnae
Vertebralis, is  situated  in  the spinal cavity, on  the posterior
face of the bodies of the vertebras, between  their ligamentous
covering and the  dura mater.  They are the general recipients
for the blood of the contiguous structure.  They detach a con-
siderable  number of branches, which run transversely,  and
anastomose with  one  another on the body of  each vertebra, so
that each vertebra  has  its little system  of  anastomosing
branches.   These junctions constitute  the Circelli   Venosi.
  Vol. II.—30 
338                   NERVOUS SYSTEM.
These  anastomoses communicate  with  the  intercostal veins,
avd, indeed, with all such as are on the outside of the spinal
column, by means of small branches that get out by the inter-
vertebral foramina.  They receive the veins from the bodies
of the vertebras, and from  the dura and pia mater of the spinal
marrow.

  The two sinuses may be traced as low down as the inferior
end of the sacrum, where they arise by small trunks from the
fatty  matter which  surrounds the lower end  of the cauda
equina.   When their size is somewhat augmented by their as-
cent, they communicate by a  large transverse branch.   The
superior end of each sinus terminates by several anastomoses
with the vertebral vein, and with the anterior occipital sinus;
through the latter of which its  blood is, finally, carried  into
the  lateral sinus.  For a  farther  account,  see Sinus Verte-
brales.
                    CHAPTER  II.

             OF THE ENCEPHALON, OR BRAIN,

  By this term is designated that section of the central portion
of the nervous system, which is contained within the bones of
the cranium.   In its general configuration it differs materially
from the medulla spinalis, in  being spheroidal or oval.  It is
surrounded by the same  membranes; to wit, the  Dura Mater,
externally, the Tunica Arachnoidea next, and the Pia Mater,
internally.
  The Encephalon  is formed by  cineritious  and medullary
matter, and, as a mass, consists of four distinct portions.   The
Medulla Oblongata, which is a continuation of the spinal mar-
row, or  its superior part; the Protuberantia Annularis, or Pons
Varolii, which is placed at the upper extremity of the Medulla
Oblongata; the Cerebrum, which occupies six or seven-eighths
of the cavity of  the cranium; and the  Cerebellum, which  lies 
MEMBRANES OF THE BRAIN.
339
upon the posterior fossae of the base of the cranium.   As the
brain is a double organ, each of these parts is symmetrica], or
consists in right and left halves perfectly alike,


  SECT. I.--OF THE MEMBRANES OF THE BRAIN, OR ENCEPHALON.

                    Of the Dura Mater.

  This membrane, the  most exterior of the three belonging to
the encephalon, lines the whole internal face  of the cavity of
the cranium,  and is attached with great tenacity to it, particu-
larly in early life,  from which cause it is also  considered  as
an internal periosteum.
  Its external surface has a rough and unequal appearance, and
adheres much more strongly  where the sutures exist than  on
the common surface of the  bones, owing to its detaching many
large  filaments, which  penetrate  into the  sutures and reach to
the pericranium.   Its adhesion to the surface generally of the
bones is accomplished by fine filaments of fibres, and by  very
numerous and small blood vessels which become evident from
the dots of blood collected upon it, when the bones are torn up,
as in the usual manner  of examining the  head.  To the  base
of the cranium, its adhesion is still stronger, owing to the abun-
dance of the foramina and fissures there; to the margin of  each
one of the foramina it  is fixed with  extreme compactness, and
may be considered as  continuous with the adjacent pericra-
nium.
  The  external surface of the Dura Mater is marked  by the
arteries and  veins which creep and  ramify  through it, and
make, as mentioned elsewhere, corresponding furrows in the
bones.
  The Dura  Mater consists  of  two laminae, one  within the
other;  they, however, are  attached so closely  in the greater
part of  their extent, that it requires the knife, or strong artificial
force, to separate  them.  Sometimes, in  tearing off the skull-
cap of  a$middle-aged  person, the external lamina is brought
away with the bone.
  Several processes arise by a duplicature of the* internal  la-
mina of the dura mater, and extend from the circumference  to- 
340
NERVOUS SYSTEM.
wards the centre of the  cavity of the cranium.  They are as
follow:—

  The Falx Cerebri separates the hemispheres of the brain, and
   consequently, precisely under the middle line of the head.
Its  shape is well indicated  by its name.   It commences by a
small point from the middle of the  body of the  sphenoid bone,
and continues to arise along the crista  galli,  the  spine,  and
'middle line of the frontal bone, the sagittal suture  and the up-
per limb of the  occipital cross, till it reaches the internal occi-
pital protuberance.   It is about  an inch broad in front, where
it begins, but it increases  continually, though gradually, in
breadth till its termination,  where it is two or two and a half
inches wide.  It is  strongly fastened along the crista galli, and
at the foramen ccecum, and being also fastened behind to the
tentorium, (with which it is continuous,) as well as along the
intermediate points of bone, it is  kept in a state of strict tension,
which does not admit of its wavering to one side or to the other.
Its  inferior margin  is very concave, and goes to within a small
distance of  the corpus callosum.  There are sometimes consi-
derable apertures in  it, through which the flat surfaces of the
hemispheres come in contact.

  The Tentorium Cerebelli, another process of  the internal la-
mina of  the dura mater, is placed transversely across the pos-
terior part of the cranium, and separates  the  cerebellum from
the posterior lobes of the cerebrum.   It is  continuous  with the
posterior end of the falx major, whereby these two processes ex-
ercise a mutual tension. The tentorium is, therefore, kept convex
above and concave below.
  Its form is crescentic; its outer  circumference is extended
along the horizontal limbs of the occipital cross, and along the
superior  corner or margin of the petrous bones to the posterior
clinoid process.   The internal circumference is much smaller
and unattached,  and being placed immediately behind  the sella
turcica, it leaves an opening (the Foramen Ovale) which is near-
ly of the same size with, and occupied by  the  tuber annulare
and the crura cerebri.  The anterior extremities of the  crescent
are continued from the posterior clinoid process to  the anterior 
MEMBRANES OF THE BRAIN.
341
 on each side, so that a deep depression is formed for lodging
 the pituitary gland.

   The Falx Cerebelli is a small triangular process of the dura
 mater, which extends in the middle line from the under surface
 of the tentorium to the posterior margin  of the occipital fora-
 men.  Its base is  above, and its point below: the latter termi-
 nates by a small  bifurcation.   It adheres by its posterior mar-
 gin to the middle inferior  limb of the occipital cross; the ante-
 rior margin is free, and serves  to separate the two hemispheres
 of the cerebellum.

   The Dura Mater  is essentially fibrous, as  is sufficiently evi-
 dent at whatever point it may be examined.   These fibres have
 no settled course, but cross each other in every direction.   It
 is white, sufficiently transparent for the vessels of the pia ma-
 ter to be imperfectly seen through it, and  almost  inelastic.   Its
 internal face is smooth and polished, and is covered or lined by
 the tunica arachnoidea, the  halitus from which gives it a slip-
 pery feel.   It is insensible to common excitants,such as cutting,
 or even cauterizing it; from which circumstance, together with
 the common  inability of anatomists to  trace nerves  into its
 structure, it is supposed,  by many,  to  be entirely destitute  of
 them.   The venerable  Chaussier, however, takes a  different
 position in regard to these points, and says, that it has sensibi-
 lity, and that  though none of the cerebral nerves can  be traced
 into it, yet,  by attentive examination, it is found, that filaments
 from the sympathetic nerve follow the ramifications of its mid-
 dle or great artery.*
   It is well supplied  with blood vessels, both arteries and veins.
 The former are derived principally from the branches of the in-^
 ternal maxillary  of either  side, which get  into the cranium
 through the foramen spinale and ovale.  There are branches
 also from ihe ethmoidal, the inferior pharyngeal, and the ver-
 tebral.  The branch of the internal maxillary called meningea
ma^na divides into two, of which the anterior being  the more
considerable, gains the anterior and inferior angle of the parie-
tal bone;  but the  other is directed backwards to the squamous

               * Exposition de L'Encephale, p. 29.
                            30* 
342
NERVOUS SYSTEM.
 portion of the temporal.  Each of these branches is subdivided
 into a considerable number of smaller ones, which for the most
 part incline backwards.  Their capillary terminations are sup-
 posed by Bichat to be in small number comparatively, and to
 be limited principally to those of nutrition.
   Some of the veins accompany the arteries., as in other parts
 of the body, and empty into the sinuses about the base of the
 cranium.  In the case of both arteries and veins, there is, how-
 ever, a very considerable anastomosis with the blood vessels of
 the diploic structure of the cranium, and  with those of  the in-
 teguments.

   Of the Sinuses of the Dura Mater.—The sinuses are large
 cavities placed between the two laminas of the dura mater, and
 receive the blood from the veins of the pia mater.   They are
 formed by the separation of these laminas, and  are lined by a
 membrane corresponding with the internal coat of the veins.

   1. The Sinus Longitudinalis Superior extends along the whole
 base of the falx cerebri, from the ethmoid bone  to the tento-
 rium, where  it terminates in  the lateral sinuses.  It begins  at
 the foramen ccecum in a small pointed manner, and, according
 to some anatomists, by a small vein, which  passes from the nose
 through this foramen;  it is successively increased in size from
 before backwards, and is of a prismatic shape.  One side of the
 prism is upwards, and, of course, is formed by the external la-
 mina of the dura mater; while the  other two parietes are late-
 ral, and are formed by  the duplicature of  the internal lamina.
 Its cavity presents a number of small cords, round or flattened,
 passing from one side to the other; they are called Chordae Wil-
lisii or Trabeculas, and prevail principally  at its back part.
   The longitudinal sinus receives on each side from  ten to twelve
large veins, which bring the blood from the pia mater.   Those
from the convex surface of the brain are joined just  before enter-
ing the sinus by such as belong to the flat side of the hemispheres.
These veins enter the-sinus, for the most part,, obliquely forwards,
or in a manner opposed to its circulation.   They are also fur-
nished with valves,  which circumstance, besides their oblique
entrance into the sinus,  is a provision  against  their being filled
by the regurgitating blood.  The most posterior ones previous- 
MEMBRANES OF THE ERAIN.
343
ly glide eight or ten lines between the laminas of the dura ma-
ter, and are somewhat tortuous.   This sinus also receives se-
veral veins from  the  bones, and  some from the  scalp, which
traverse the bones at different places: among the largest of them
are those that come through the parietal foramina.   The dura
mater itself sends some of its veins into this sinus.
  In the longitudinal sinus, towards its posterior part, is found
a considerable but variable number of small granular bbdies;
some in clusters, others insulated; and from the size of a pin's
head to a line or more in diameter.  They are the Glandulae
Pacchioni: they have no excretory ducts that  have been dis-
covered, and it is entirely uncertain whether any specific  fluid
is secreted from them.  These bodies are  also  to be found on
the surface of the dura mater near this sinus; some of them, in-
deed, make foramina through the dura mater, and corresponding
depressions in the* skull.   One on each side, larger than usual,
and near the parietal  foramen, is remarkable for this.

  2. The Sinus Laterales, one on each side, are situated in the
base of the tentorium, and follow its course along the grooves of
the occipital and parietal bones.  They then leave the tentorium
and go  along the  groove in the mastoid portion of the temporal
bones to reach  the  posterior foramina lacera, where they ter-
minate in the internal jugular veins.  Their shape is ovoidal,
instead  of prismatic, as  the longitudinal sinus is; they are also
larger than it.
  The sinus of the right  side is very frequently larger than that
of the left,  and seems  to be more a continuation of the superior
longitudinal sinus.  In some rare cases one of these sinuses is
deficient.   The lateral and inferior veins of the cerebrum, and
the inferior veins  of the  cerebellum run into the lateral sinuses.

  3.  The Sinus Longitudinales Inferior is .situated in the falx
cerebri  just above its  concave edge.   It is much smaller than
the superior, and  terminates behind in the sinus  quartus.  It re-
ceives the veins of the falx, and sometimes a few from the cor-
responding parts  of the hemispheres.

  4. The Sinus Quartus, or rectus, is situated in the  tentorium,
where the  latter  is joined by the falx major  or cerebri.   It is 
344
NERVOUS SYSTEM.
 triangular or prismatic, and runs from the anterior margin of
 the tentorium to the posterior, where it terminates in the extre-
 mity of the  longitudinal sinus.  The general union which is
 there formed between the longitudinal, the fourth, and the lateral
 sinuses, constitutes the Torcular  Hierophili.
   The anterior extremity of the  fourth sinus, besides receiving
 the inferior longitudinal, is joined by the Vena Galeni, a single
 trunk, formed by the junction of the two veins of the middle of
 the velum interpositum, and extending from the posterior margin
 of the fornix to the beginning of  the sinus  quartus.  The Sinus
 Quartus, in its course, also  receives the superior veins of the
 cerebellum, with  the exception of the most anterior ones, which
 terminate in the Vena Galeni.

   5. The Sinus Petrosi are small cylindrical cavities, and are
 so called from being situated on the petrous bone.   There are
 two on each side; one above and the other  below. The former
 is the  Superior, and runs from the cavernous sinus along the
 superior margin of the petrous bone to join  the lateral sinus,
 where the latter quits the tentorium to descend towards the base
 of the  cranium.  The other Petrous Sinus is the Inferior.   It is
 larger  than  the superior, and arises, also,  from  the  cavernous
 sinus by its posterior margin.  It  then runs along the-fissure be-
 tween  the occipital and  the petrous bone, leaving its mark on
 the margin of these bones, but principally on the former, and
 then terminates in the lateral sinus just above the posterior fora-
 men lacerum.

  6. The Sinus Cavernosi, one on each side, are also  formed by
 a separation of the two laminas of the dura  mater, though their
 shape is so different from that of the others.  They are situated
 at the sides of the sella turcica, and on the body of the sphenoid
 bone.  Their cavity is very irregular, and  is  furnished with a
 number of filaments, which  cross in every direction, and give
 it a cellular  arrangement.  The internal carotid artery and the
sixth nerve traverse it, but are protected  by its lining membrane
 being reflected over them.
  The cavernous sinus anastomoses  in  front with the circular
 sinus, and behind  with the two petrous sinuses and the anterior 
MEMBRANES OF THE BRAIN.
345
occipital. It receives, in front, the ophthalmic veins; from above,
the anterior and inferior cerebral  veins; and on the sides, some
veins from the dura mater.

   7.  The Sinus Circularis is placed in the sella turcica, and
surrounds the pituitary gland.  It is a  small cavity which  re-
ceives the veins  of this gland, and, as just mentioned, commu-
nicates with the cavernous sinus.

   8. In the  posterior part of the base of the cranium, there are
also some other sinuses, called, from their position, Occipital.
One of these, the Anterior, is upon the basilar process of the os
occipitis, and  extends  itself directly across the  bone, from the
hind part of one cavernous sinus to  the corresponding point of
the other; and is, therefore, a means of communication between
these two cavities.  Another of these sinuses, the posterior, ex-
tends from the region of the torcular Hierophili, or the upper extre-
mity of the  lateral sinuses, along the base of the falx cerebelli,
to the posterior margin of the occipital foramen, where it bifur-
cates, and then goes along the margin  of this foramen to dis-
charge itself into the lateral sinus at the posterior foramen  la-
cerum.

   The smaller sinuses about the  base of the  cranium, besides
the outlets  mentioned, have  collateral ones, which pass at dif-
ferent places through the base of the cranium, and run into the
branches of *the  internal jugular vein.   These communications,
as mentioned  in  the account of the veins, were known to San-
torini, and are called his Emissaries.


                 Of the Tunica Arachnoidea.

   This membrane is  the  second of  the envelopes of the brain,
and is spread  over the surface of the pia mater, adhering to it
closely in the  greater part of its extent.   It is  so diaphanous
and thin, as its name implies, that it  is distinguished with  some
difficulty, wherever it adheres to the pia mater;  which it does
all over, with  the exception of some few places  on the basis of
the brain, as,  for example, just in  front of the tuber  annulare,
and behind the medulla oblongata.   There this membrane may 
346                   NERVOUS SYSTEM.
 be seen  stretched from one prominence to another, and sepa-
 rated  considerably  from the pia mater.   It does not dip into
 the  fissures of the brain, but goes  directly across them,  from
 the ridge of one convolution to  that of the adjacent, so that it
 is entirely smooth and  uniform in its  distribution.   Notwith-
 standing the general closeness of its connexion with the pia ma-
 ter, it may yet be separated from it by careful  dissection,  by
 slight maceration, or by the use of the blow-pipe; dropsical ef-
 fusions  frequently make  out the  distinction between the two
 membranes; also the deposite of coagulating lymph.
   Considering this membrane  as  a single  layer, we have  to
 speak of tho dura mater, as lying loosely upon it.  But the au-
 thority of Bichat, sanctioned by  the testimony of many other
 anatomists, has assigned to  it a  much more considerable extent.
 For it seems to be well ascertained, both by analogy and by ob-
 servation, that it is a sac; which, besides covering the external
 surface of the pia mater, is reflected  over the  internal  surface
 of the dura mater, and gives to  the latter  its  smooth shining
 appearance.   This lining is on  the same principle that  the  se-
 rous lamina of the pericardium  lines its fibrous lamina,  or that
 the synovial  membrane lines the ligamentous  attachments  of
 an  articulation.   In the early  periods of  life, it may be  sepa-
 rated from the dura  mater, by  dissection.   Vicq. D'Azyr has
 related a case in  which it was detached by a collection of pus.
 Its places of reflection to the dura mater are on the basis of the
 cranium, where the blood  vessels  and nerves  pass  into the
 sheaths formed by the dura mater, and  along the blood vessels
 entering into  the sinuses.   This membrane  is continuous with
 the tunica arachnoidea of the medulla spinalis.
  The tunica  arachnoidea*  is considered to pass into the ventri-
cles of the brain by the same apertures that the pia mater  does,
but it is much less manifest  there than elsewhere.
  The texture of this membrane is exceedingly delicate and
fine.   It  is always found,  in  health,  in  a  transparent  state,
and  is furnished with neither   red  blood vessels nor nerves.
It  secretes a  sort of halitus, or synovia, which facilitates the
  * As the ventricles of the encephalon are but fissures in its structure, this ar-
rangement is in oppositiou to that of the fissures on the surface of the encephalon,
and in fact, may be doubted from its defective evidence, excepting in the case of
the Velum interpositum. 
MEMBRANES OF THE BRAIN.
347
motions of the brain,  and prevents it from adhering.   Occa-
sionally, this secretion is  so  much augmented as  to constitute
a genuine dropsy.

                      Of the Pia Mater.

  The Pia Mater, or Tunica Cerebri Vasculosa, is in contact
with the substance of the brain.  It also is  extremely delicate,
but, unlike the last, is furnished with an  immense number of
blood vessels which go to or return from the brain, and  are,
in most subjects, so abundant that they give a florid appearance,
at a little  distance, to the whole membrane.   Its external face
appears entirely  smooth,  owing to its being covered, and its
processes  cemented together by the tunica arachnoidea ; but its
internal face exhibits  these  processes  as penetrating  to the
bottom of the fissures of the  brain; consequently, it is very un-
equal.
  The pia mater presents, along the course of the longitudinal
sinus, an abundance of those small graniform bodies, existing
also in this sinus, and called  Glandulas Pacchioni.   They beset
the veins  as they enter into the  longitudinal  sinus, and even
follow them there, so that there is a chain  of them  from the
surface of the pia mater,  into the  sinus.   They are frequently
so abundant on the superior  part of the  hemispheres, near the
great fissure, that they cause  the dura and pia mater to adhere,
as if  from inflammation.   It is the larger of this kind which
frequently produce an  absorption of the dura mater, and of the
internal table of the skull.  These bodies are also found, along
with the pia mater, in  the ventricles of the brain, as at the ex-
ternal margin of the plexus choroides, around the  pineal gland,
and at the bottom  of the fourth ventricle.
  The Glandulas  Pacchioni,  wherever found, present a similar
appearance  and structure, but varying much in size: they are
generally  in clusters, which repose on common bases.  Anato-
mists differ  much in their opinion concerning them.  Bichat
acknowledges  his complete ignorance  on the subject; Portal
says that  they are only congeries of vessels or of cellular bo-
dies filled  with fat.  Meckel  states, that as they are found es-
pecially in the latter periods of life, and never before birth, and
as they never exist in very great abundance, except in persons 
348
NERVOUS SYSTEM*
  who have often experienced diseases of the head, and are not
  observed  in any animal; so we are forced  to  consider them
  as  morbific productions,  and  not, as  Pacchioni conceived,
  glands whose excretory ducts opened into the ventricles of the
  brain and the sinuses.

    The Pia Mater covers the upper surface of the cerebrum with
  such uniformity as not to require a detailed description of  it;
  where it sinks into the  great fissure between the hemispheres,
  it adheres from the two sides just above the corpus callosum.
  On the basis of the brain, it penetrates deeply into the anterior
  fissure, or the Fissura Sylvii;  is reflected over the inequalities
  of the  brain, but never in such a way as to leave them; and
  secures the bottom of the third and of the fourth ventricle.
    The distribution  of the pia mater, over the ventricles of the
  brain, is more complicated than that over its periphery, and it
  may be remarked, that this portion  is called, by some  anato-
  mists, the Internal Pia Mater; that its texture is much  more de-
  licate, and net-like, and that it adheres more closely to the sub-
 jacent parts.  Being extended from the  superior  surface of the
  cerebellum and of the Pons Varolii, it enters into  the third ven-
  tricle,  under the posterior margin of the fornix, by the large
 transverse fissure between the latter and the tubercula quadrige-
 mina.   By its course between the fornix and thalami, it consti-
 tutes the Velum Interpositum, or the Tela Choroidea  of Vicq.
 D'Azyr. The pia mater is also introduced into the inferior cor-
 nu of the lateral ventricles along the internal margin of the hip-
 pocampus major, at the  side of the pons varolii; and  into the
 fourth ventricle from its bottom part.
   The  several plexuses of vessels found in the ventricles of the
 brain have for their basis the pia mater; which is there arranged
 into a great number of folds, some of them being longitudinal
 and others crossed.  Their formation, according to °the new
 views which have been taken  of the  development and growth
 of the brain, by Tiedemann, depends upon the internal mem-
 brane of the brain contracting itself as it finishes the deposite
.of medullary matter called Centrum Ovale.  The vessels of the
 plexuses are the arteries, which are spent upon the surface of
 the ventricles, and the veins derived from the same; the latter
 are much more numerous than the first. 
THE MEDULLA OBLONGATA.                349
   Of the Structure of the Pia Mater.—The pia mater is com-
monly spoken of as a complete  membrane, yet its structure is
different from that of membranes generally, inasmuch as it is a
net-work, the meshes of which are formed by arteries and veins,
and the interstices filled up by a loose, weak cellular substance.
Bichat has very justly observed, that the union with the tunica
arachnoidea is solely on the part  of this  cellular  substance;
whereas, the union with the cerebrum  is  confined to the ves-
sels, which are extremely numerous and, very small before  they
penetrate it, and appear as bloody points when we cut into the
substance of the  brain.  The principal arterial trunks of the
pia mater, being  the  internal  carotids  and the vertebrals and
their branches, are at the basis of the brain; these trunks divide
into smaller branches, on the convolutions and in the fissures.
The primary divisions  again  divide and subdivide into tubes
not  much  exceeding the size  of the capillary  vessels.  In
this last state  they enter the brain  and  may be seen  very
readily, either  by a  fine injection, or by  tearing up  the pia
mater.

            SECT. II.--OF THE MEDULLA OBLONGATA.

   According to the usage of the best authorities of the present
day, who follow in the description  of the central parts of the
nervous system, the  order of  their  development in the  human
subject, and also of their appearance in animals, I shall describe
the encephalon  from  below upwards  instead  of from above
downwards.  The preference thus shown  is, perhaps, princi-
pally serviceable in  fixing upon the mind the order of growth
and  appearance, which, according  to well  established experi-
ments, are exactly in the order of importance to life.

   The Medulla Oblongata, also  called  Bulbus Rachidicus, ex-
tends from the superior margin of the first cervical vertebra  to
the middle of the basilar process of the os occipitis.  It becomes
gradually larger as it ascends, and  is about an inch  in  length,
and eight lines wride at its base.  It is by  no means so cylin-
droid as the medulla  spinalis, but presents  several risings and
depressions on its surface.
   The under surface of the Medulla Oblongata is divided longi-
tudinally by the  middle fissure,  a continuation of that  on the
   Vol. II.—31 
350
NERVOUS SYSTEM.
front of the Medulla Spinalis.  The fissure is two or three lines
deep, which is  rendered manifest  by removing the pia mater.
The Corpora Pyramidalia  are  placed one on either side of it,
and are oblong bodies;  being a continuation of the chords that
decussate from the opposite sides of the spinal marrow.  These
bodies occupy the whole length of the Medulla Oblongata, in-
crease in breadth as well  as in elevation during  their ascent,
and are, lastly, somewhat constricted or diminished  abruptly,
where  they  join  the  Protuberantia Annularis or Cerebralis.
Precisely at the latter point, between their bases, is a deep tri-
angular pit, into which  penetrates the pia mater.  J. F. Meck-
el  says, that they are united  at  their lower extremities by a
small transverse medullary Commissure of a line and a half in
breadth.  This junction is  above the decussation of the chords
from which the Corpora Pyramidalia arise.

   The Eminentias Olivares are two bodies; one on either side,
at  the external margin of the corpus pyramidale.   They are
about seven lines long:  two and a half wide, and  are elevated
to the heiorht of one line. The elevation ceases somewhat short
of the annular protuberance, but their anterior structure is con-
tinued into the latter, and may be traced into the thalamus ner-
 vi  optici. .
   Like the pyramidalia, those bodies are medullary externally;
 but within, there is a nucleus of cineritious matter, called, from
 the irregularities of its  margin, Corpus Fimbriatum, and which
 encloses some medullary matter.  The corpus fimbriatum is open
 at the inner circumference, and has the medullary matter which
 it contains, continuous  there with the substance of the  corpus
 pyramidale.  Below, its circumference is continuous with the
 cineritious matter of the medulla spinalis.   In the slight depres-
 sion between the corpus pyramidale and the eminentia olivaris,
 are the roots of the hypoglossal nerve.

    The Corpora Restiformia, also  one on either side, are placed
 at the lateral posterior margins of the medulla oblongata, just
 posterior to the Eminentias olivares ; and are readily brought into
 view by elevating the contiguous parts of the cerebellum.  They
 are elliptical risings of an inch in length; their lower extremi-
 ties are in contact, and project where they begin to arise from
  the borders of the  posterior fissure of the medulla  oblongata; 
THE MEDULLA OBLONGATA.
351
they then diverge, and advance forwards  and upwards to ter-
minate above in the cerebellum.
  The corpus restiforme is formed of medullary matter, and is
a continuation of the  posterior chord of the medulla spinalis.
From its superior posterior margin a  thin medullary lamina of
about three lines square arises, and being  sustained by the pia
mater, advances to meet its fellow, but does not absolutely touch
it.*  From the anterior margin of each corpus restiforme there
departs a second process of medullary matter, larger and more
thick than the preceding, and being covered by the roots of the
pneumogastric  and glosso-pharyngeal nerves,  adheres  to  the
plexus Choroides of the fourth ventricle.
  The superior face of the medulla oblongata is excavated be
tween  the  corpora restiformia, in such a way as to present the
outline  of  a writing  pen, and  is, therefore, called  Calamus
Scriptorius; which forms a considerable part of the floor of the
fourth ventricle of the Brain, or  the sinus rhomboideus.  The
fissure,  in  its middle,  corresponds with  the slit of a pen, the
nib being downwards; and the fissure extends  from the poste-
rior fissure of the medulla spinalis the whole length of the me-
dulla oblongata.
  The calamus scriptorius is marked by several streaks of me-
dullary matter, which extend  themselves transversely with a
very slight degree of obliquity upwards, and reach the external
margin of the  corpus restiforme of  the  corresponding  side.
These medullary strias present some varieties in regard to their
volume, number, and arrangement.  Sometimes they are slightly
elevated narrow lines,  which are perfectly distinct from each
other,  and from one to fourteen in  number.   On other occa-
sions their volume is  greater, but they are not so numerous.
They generally extend, either one or all, from the middle fis-
sure to  the  commencement of  the  auditory  nerve, and  are
thereby a part of its origin.   Sometimes the anterior ones are
directed towards the origin of the trigeminus  nerve, but  their
union with it is not yet ascertained; the posterior ones are some-
times blended with the radical filaments of the pneumogastric
nerve.   The  strias  themselves,  are  sometimes interwoven or
blended, and  pass the boundary  of the  middle fissure to join

            • Called Pons Sinus Rhomboidei by J. F. Meckel,* 
352
NERVOUS SYSTEM.
with those of the other side.  Their roots may be traced occa-
sionally along  the middle fissure, almost  to the front or under
surface of the medulla oblongata.  Meckel, whose observations
on this  subject are highly interesting, is disposed  to consider
the striae not only as forming the  roots of the  auditory nerve,
but as also related closely to the trigeminus and to the pneumo-
gastric.
  On this surface, also, of the  fourth ventricle, or sinus rhom-
boideus, but in advance of the preceding  striae, there is another,
on each side, still larger, which may be distinguished by its al-
ways beginning at some distance from the middle fissure.   Its
direction is transverse, and it passes just above the anterior ex-
tremity  of  the  corpus restiforme, to  run into, or to assist in
forming, the root of the auditory nerve.   Its existence is much
more constant than that of the  others.  It is considered as an
assistant ganglion to the auditory nerve, and in cases of deaf-
ness  has  been deficient.  Being  principally cineritious, it is
called Fasciola Cinerea.
  In  tracing the continuation of the structure of the medulla
spinalis, into that of the medulla oblongata, we find that each
of the anterior cords of the medulla  spinalis, besides crossing
with  some of its fasciculi at the place mentioned, to wit, at the
decussation of Mistichelli, and continuing their course upwards
to form the corpus pyramidale, sends  off a  larger fasciculus,
which ascends behind  the eminentia  olivaris, and forms the
floor  of the sinus rhomboideus.  There is yet another fascicu-
lus of white matter between the others, according to Rosenthal,
into which the anterior column of the medulla spinalis is di-
vided.  He  says, that  it  touches the eminentia olivaris,  sur-
rounds  it,  and, after having traversed  the  annular protube-
rance, terminates in the tubercula quadrigemina.
   The posterior cords  of the Spinal marrow,  being continued
into the corpora restiformia, become  still more evidently di-
vided into  two fasciculi, from an increase of their volume, than
they  were in the  vertebral canal.   The internal of these fasci-
culi stops,  by a pointed termination, near the borders of the
sinus rhomboideus, or fourth ventricle of the Brain;  while the
external is continued on through the annular protuberance to
the cerebellum. 
PROTUBERANTIA ANNULARIS.
353
              SECT. III.--PROTUBERANTIA ANNULARIS.

   The Annular Protuberance (Protuberantia  Annularis, Ab*
 dus Cerebri,  Pons Varolii) is the large projecting body, placed
 near the  centre of the base of the encephalon, at the top of the
 medulla  oblongata, and upon  the junction of the body of the
 sphenoid bone with the basilar process of the os occipitis.   It
 is convex, and about an inch in  diameter, its transverse mea-
 surement being a  line or two larger than the other.  It is  di-
 vided by a superficial fossa into two symmetrical  halves, rio-ht
 and left.
   When  the pia mater is removed from the Protuberantia An-
 nularis, the under surface of the  latter is  seen to be formed by
 transverse medullary fibres which come  from the crura cere-
 belli.  When  these, which  are commonly one or  two lines in
 depth, are removed by scraping or cutting, a cineritious mat-
 ter is exposed, which is  traversed by numerous layers  of me-
 dullary matter, also going  in a.  transverse direction-  About
 two lines  deep from the surface of the  protuberance, near the
 middle of each of its halves, are found some longitudinal me-
 dullary fibres connected with cineritious matter, and which
 may be fairly  traced as a continuation of the filamentous struc-
 ture of the pyramidal bodies.  These  fasciculi, or  filaments,
 passing on  through the  protuberance,  are  continued so as  to,
 form the under surface of the crura of the cerebrum.
   Lying still deeper than the medullary fibres alluded to, there-
 is an accumulation of cineritious matter, intermixed with  per-
 pendicular medullary layers situated one behind the other.  Be-
 hind (or above when we stand  erect) this intertexture, a small
 fasciculus (the cord described by Rosenthal) of medullary mat-
 ter exists, which is  a continuation  of  the intermediate fascicu-
 lus of the anterior medullary cord of the medulla spinalis, and
 may be traced afterwards to the superior face of the erus cere-
bri, where it terminates, as alleged  by Rosenthal, in the  Tu-
bercula Quadrigemina.
3L* 
354
NERVOUS SYSTEM.
               SECT. IV.--OF THE CEREBELLUM.

  The Cerebellum, being placed in  the posterior fossae of the
cranium, is separated by  the  tentorium from  the  posterior
lobes  of the cerebrum, beneath which it  lies.  It is connected
with the Pons Varolii by a trunk of medullary matter on each
side, called the crus of the cerebellum; and which is a root of
the medullary matter entering into  the composition of the
pons.
  It is of a rounded form, and well fitted  to the cavity in which
it reposes.   It is convex above and below; measures about four
inches in its transverse diameter, two and a half in thickness,
and about the same from before backwards.  The upper face
is divided into two  equal  parts  or  halves, by a  middle ridge,
while the lower face  is divided in  the  same way by a fossa.
These halves  are called hemispheres; their surface is marked
by  many horizontal fissures, the edges of  which are kept closed
by  the adhesion of the pia mater.
  The fissures are interposed between the laminas or convolu-
tions of the cerebellum, which, for  the most part, are concen-
tric;  the  larger fissures  are behind, while the shortest are  in
front, near the annular protuberance.   The pia mater  pene-
trates to the bottom of these fissures, some of which, when ex-
posed fully by its removal, are found to  extend to the depth of
an  inch or more.   One of these fissures, which  exists on  the
superior surface of the cerebellum, half an inch distant from
the posterior and external margin of the latter, has a circular
course, and is so well marked by its size and depth, that it is
called the Sulcus Superior Cerebelli.  Another, situated under
similar circumstances on the inferior surface of the cerebellum,
is called the Sulcus Inferior Cerebelli.  On  the latter surface,
also, there are two or three more  of a middle size, situated
between the  sulcus inferior and the annular  protuberance.
These larger  sulci have given occasion to anatomists to multi-
ply most unreasonably the number  of lobes of which the cere-
bellum consists.  Bichat's mode of description  is preferable:
he  says, that  by cutting (vertically) through one of the hemi-
 spheres of the cerebellum, so as to expose the thickest part of 
THE CEREBELLUM.
355
its medullary matter, six or seven  principal fissures will be
seen, which, by penetrating to a considerable depth, divide the
cineritious portion into as many converging parts.   In the in-
terior of these fissures there are much smaller ones,  which pass
at right angles to them.  On the surface or periphery of the
cerebellum,  in the intervals of the larger fissures, there are
many small  ones, which, though nearly horizontal, terminate
in each other  by  acute angles.
   The superior middle ridge of the cerebellum, from its shape
and position, is called, by Vicq. D'Azyr, Vermis Superior; the
anterior extremity of which, from its elevation, is  the Monti-
culus Cerebelli.
   The middle inferior part of the cerebellum, which presents
the deep sulcus running longitudinally and forming the division
into hemispheres, has a  long ridge occupying the sulcus.   This
ridge is the Vermis  Inferior of  Vicq. D'Azyr, and is so  con-
cealed  by the adjacent portions  of the hemispheres, that a
good view of it can be  got  only by removing  the arachnoidea,
pia mater and pushing the  hemispheres  aside.   The transverse
fissures which penetrate it,  and its general irregularity of sur-
face,  will then be sufficiently distinct.  The pia  mater and
arachnoidea pass from the  fore part of this body to the medulla
oblongata, and thus  assist  in forming the  floor of the fourth
ventricle; which, without  this  reflection, would be exposed.
The central part of the cerebellum as  formed  by the vermis
superior and  by  the vermis inferior, is  the Fundamental  Por-
tion of Gall  and Spurzheim.
   At the root of the crus cerebelli are two small protuberances;
the one below it, in  the erect position, is the Lobulus Amygda-
loides, and  the other the Lobulus Nervi Pneumogastrioi.
   The substance of the  cerebellum is formed of cineritious mat-
ter externally, and of medullary matter internally.  When a
vertical section of it is  made through the middle of one  of its
hemispheres,  the medullary neurine or  matter puts on the ap-
pearance of the thuya or arbor vitas, the roots and ramifications
of whose limbs,  even  to their  smallest extremities, are  sur-
rounded by cineritious  neurine or matter.  In this  view, there
appears to be more  cineritious than white matter; but when a
horizontal cut is  made from the periphery to the centre, paral-
lel with one of the deep concentric  fissures, the proportion of 
356
NERVOUS SYSTEM.
medullary matter seems to be much more considerable; and the
arbor vitae arrangement is  proved to depend upon the laminae
of medullary matter  radiating from the centre, or, in  other
words, from the massive medullary trunk in the interior of the
hemisphere of the cerebellum.  Each of these radiations com-
mences by a root of considerable size, which divides and sub-
divides into branches.  Each primitive radiation, as well as its
branches, is  covered by its own layer  of cineritious matter
about one line in thickness, and is kept perfectly distinct from
the contiguous ones  by the  fissures which extend  internally
from the periphery of the cerebellum.
  In the middle of the trunk of the arbor vitas, exists the Cor-
pus Rhomboideum, or Dentatum.  It is an oblong rounded  body,
jagged and cineritious in its circumference, but medullary with-
in.   Its configuration resembles that of the corresponding body
in the eminentia olivaris, with the addition of its being larger,
and having its outline better marked.  It is the-ganglion of the
cerebellum of Gall and Spurzheim.
  The Valve of Vieussens (Velum Medullare, Valvula Cerebri)
arises from the cerebellum, just under the anterior part of the
base of the monticulus, and runs obliquely upwards to  terminate
in the testes.  Sometimes it is marked in its  middle,  by a lon-
gitudinal line or slight fissure, from  either side of which pro-
ceed small lateral ones.  It is principally medullary,  and has a
small quantity of cineritious  matter  at its extremities.  It is
thinner in the middle than at either of its margins.
  The Central or Fundamental Portion of the Cerebellum ex-
hibits also very clearly the arborescent arrangement, and is fur-
nished with about seven primitive radiations, coming from  a
medullary trunk.  The proportion of medullary matter to corti-
cal, is  less in it than in the  hemispheres of the cerebellum.
Each of the primitive radiations may  be traced to some particu-
lar point or prominence on the surface of the fundamental por-
tion, thus forming its basis; but this study is moTe curious than
useful, though several anatomists  have pursued it.
  Three  medullary fasciculi,  on  each  side, have now been
traced to the cerebellum; one of these is the continuation of the
corpus restiforme of the medulla oblongata; a second is the val-
vula cerebri; and the third, the Crus  Cerebelli, which joins the
annular protuberance.  The two  first fasciculi  belong, to the 
THE CEREBRUM.
357
middle or fundamental  portion of the cerebellum; they are,
consequently, situated more internally, and  are partially con-
cealed by the crus cerebelli, and have interposed between them
and the latter, the Corpus Rhomboideum, or Dentatum.
                 SECT. V.--OF THE CEREBRUM.

  The Cerebrum weighs about three pounds, and is seven times
as heavy as the cerebellum.   It is ovoidal, and measures about
six inches in  its antero-posterior diameter, five inches in its
greatest breadth, which is behind, and four or five in depth. It
is separated above by a deep fissure, (Fissura Longitudinalis,)
into two equal parts, called  Hemispheres.  At the bottom of
this fissure, by separating the contiguous surfaces of it, is to be
seen a broad lamina of medullary matter passing from side to
side, and called the Corpus Callosum, which connects the  two
hemispheres together.   The under surface of each hemisphere
is subdivided into three lobes; Anterior, Middle, and Posterior.
  The anterior lobes are placed upon the anterior fossas of the
base of the cranium; the Middle, upon the middle fossas of the
same;  and the Posterior Lobes rest  upon the tentorium.  The
two anterior  lobes  are completely separated by the Fissura
Longitudinalis, which extends between them to the base of the
cranium;  the  same  is the case with the posterior lobes; the
middle lobes have interposed between them the annular protu-
berance and the crura cerebri. When the pia mater is removed,
the anterior lobe is seen to be marked off from the middle lobe
by  a deep sulcus, the fissure  of Sylvius, in the under surface of
the cerebrum, corresponding, in its position, with the posterior
margin of the Lesser Sphenoidal Wing. The boundary between
the middle and the posterior lobe is, by no means, well defined
on the basis of the brain, but it  is agreed  to consider as poste-
rior lobe,  all that part of the hemisphere  which rests upon the
tentorium.
  The periphery of  the cerebrum is formed into convolutions,
(Gyri) which  give it an unequal tortuous surface, resembling
the intestines of  a small child.   These convolutions are sepa-
rated by fissures (Sulci) of depths varying from an inch to  two 
358
NERVOUS SYSTEM.
inches or more.  The convolutions  proceed in  diversified and
complicated courses, which  never correspond in different indi-
viduals, and seldom on the two hemispheres of  the same brain.
Though their summit is generally  convex, yet some of them
have it depressed slightly, which is  considered a proof of each
convolution being divisible into two halves or layers, placed side
by side.  Some of the convolutions  are short, others long; they
present numerous varieties in the manner of joining each  other.
Owing to the narrowness of the fissures between them, they are
closely packed together, so that the lateral surfaces of each  one
are suited  to such as are contiguous: occasionally, there is a
departure from this rule.
  The surface of the  convolution, by which we mean not only
the most exterior periphery of the cerebrum, but also the surface
formed by the fissures to their very  bottom, is covered by cine-
ritious neurine or matter of about one line in thickness.
  Within the periphery of the cerebrum, the mass of medullary
neurine or matter is  very considerable, and is of an ovoidal
shape.  This ovoid is called the Centrum  Ovale of Vieussens,
and is  brought  fairly  into  view  by making a horizontal  cut
through the hemispheres, two inches below  their summit.

  In  proceeding with the anatomy of the cerebrum from its
base upwards, the following is the order or succession of parts
in its structure:  In advance  of the  pons varolii, and springing
from  it, there are two divergent medullary trunks,  one on each
side, which run forwards, and are lost in the  medullary sub-
stance of the cerebrum.   These trunks are the crura cerebri,
upon  the upper surface of each are two protuberances: the pos-
terior is the thalamus nervi  optici, and the anterior is the cor-
pus striatum.  Each crus cerebri,  having  penetrated into the
substance of its respective hemisphere, expands by a multipli-
cation of the filaments composing it, so as to constitute the prin-
cipal bulk of the hemisphere.  These filaments  may, indeed, be
traced very satisfactorily in  almost every direction towards the
periphery of the cerebrum, where they terminate in the convo-
lutions, their extremities being covered  by the  cineritious mat-
ter there.   The arrangement  is best seen by scraping with  a
knife along the base of the brain, especially when the latter has 
THE CEREBRUM,
359
been hardened in spirits of wine, and it is constituted by what
are called, by MM. Gall and Spurzheim, the diverging fibres of
the brain.
  The point  is not, indeed, entirely settled that the diverging
filaments  end in the convolutions, or do not rather afterwards
inflect or double  on themselves, and pass inwards  again to the
middle line of the brain, forming, by their convergence, the cor-
pus callosum.  At all events, the fact is quite demonstrable, that
as the under and  lateral portions of the hemispheres consist in
diverging filaments, arising in and from the crus cerebri, so the
upper portion and the corpus callosum, consist in filaments which
arise  in the adjoining convolutions, and collect towards the mid-
dle line of the corpus callosum, where they adhere to the con-
generic filaments of the other side.
  The arrangement, in the most simple conception  and illustra-
tion of it, would be exemplified by folding a strip of cloth double
on  itself, so as to  convert it into a loop; the under part of the
loop would then  represent the diverging fibres of the cerebrum
and the upper part the converging fibres, or corpus callosum;
it being at the same time borne in mind that the continuation of
the two orders of fibres into one another in the brain is not so
fully ascertained as it would be represented by this model.
  Between the two orders of fibres there is a horizontal cleft or
interval.  This interval is the lateral ventricle of the hemisphere,
which may be got into under the posterior margin of the corpus
callosum, from its being open there,  or rather only closed* by an
adhesion of the membranes, which is easily lacerated.
  The preceding is intended as a mere outline upon  which to
form  the base of the descriptive anatomy of the cerebrum.
The following, therefore, may be considered as the  detailed ac-
count:—
  The Crura Cerebri are rounded below;  are about eight lines
long,  and increase in their transverse diameter as they  advance;
their  vertical diameter is about ten  lines.  They mutually di-
verge, beginning from their roots, and are separated by a deep
fissure,  considered as a continuation of that on  the front of the
medulla oblongata.  This  fissure is the third  ventricle of  the
brain.  Their surface is marked by superficial furrows, running
longitudinally; and about two lines before the  tuber annulare,
by a  transverse  fasciculus  of medullary matter, very slightly 
360
NERVOUS SYSTEM.
elevated: the optic nerves also cross them obliquely at their fore
part.
   In regard to texture, the crus cerebri presents, on its under
surface, a medullary layer of two lines in thickness; to this suc-
ceeds a parcel of cineritious matter, which, on being removed,
is followed by a mixture of both cineritious and white matter,
more abundant than either of the preceding.

   The  Eminentias Mammillares, or  Corpora Albicantia,  are
two small bodies,  one  on each side, about the size of a French
pea.  They are situated near  the anterior extremities of the
crura cerebri, on  their internal faces, and almost in contact
with each other.   Their texture is medullary without, and cor-
tical within.

   The Infundibulum is placed  immediately before the eminen-
tias mammillares.  It is a  flattened conoidal body, half an inch
long, with its base upwards, and its apex going downwards and
forwards.  It is formed of cineritious matter.  Most generally
its base is hollow,  and opens into the third ventricle, but its point
is closed.  J. F. Meckel, however, asserts that a communication
exists entirely through it, from the pituitary gland to the third
ventricle, and that he has frequently proved it by passing air or
liquids from this gland, though the experiment does not succeed
when he attempts  the injection from  the third ventricle.

   The Pituitary Gland (Glandula Pituitaria) is situated in the
Sella Turcica, and is covered so completely by the dura mater,
that only  a small aperture is left for the point of the  infundibu-
lum to pass through  and to adhere to it.  It is an ovoidal body,
the greatest diameter of which is transverse, and amounts  to
six lines.  It is partially divided, so as to give the appearance
of two lobes, of which the anterior is much the larger.  It is
hard and  cineritious, with  a small quantity of medullary matter
within.   In either  side of it there is a depression from which
leads a  small canal towards the place where the  infundibulum
joins it: the two canals are, in the latter place united into one.
In  some very rare cases, gritty matter has been found  in  it,
as there is in the  pineal gland.  It is also surrounded by pia
mater. 
THE CEREBRUM.
361
   The Tuber Cinereum, or Pons Tarini, is a portion of the un-
 der surface of the crura cerebri, at the floor of the third ven-
 tricle.  It is continuous in front with the anterior margin of the
 corpus callosum.  In front of the infundibulum the optic nerves
 unite, after having crossed obliquely  the crura cerebri from
 without inwards and forwards.  In  this passage, where they
 reach the middle of the crura, and  at the internal border of the
 same, they come in contact with the tuber cinereum,from which
 they  get a few filaments; but of this, more hereafter,

   The Thalami Optici, called, by Gall, the Posterior Ganglions
 of the brain, (Ganglia Postica,) are amongst the most conspi-
 cuous parts of the internal structure of the cerebrum, and are
 two in number, one for either side.  They are situated on the
 superior face of the crura cerebri, are about an inch and a half
 long  from behind forwards, and about eight or ten lines broad
 and deep.
   The thalami are convex above and internally.  At the junc-
 tion  of these  two surfaces is  observed a medullary  line, de-
 scribed under the name of peduncle of the pineal gland.  Their
 posterior extremity is likewise convex, and is divided into three
 rounded prominences; one is above  the other two, and is the
 Tuberculum Poslerius Superius; the second is below and with-
 in, (Corpus Geniculalum Internum,) and the third is  below and
 external, (Corpus Geniculalum Externum.)  There  is a fourth
 tubercle (Tuberculum  Anterius) which  is situated on the upper
 convex surface of the thalamus; it is produced by the fan-like
 termination of a large medullary fasciculus which comes from
 the eminentia  mammillaris.
   The thalami are  somewhat  flattened on the middle of their
 convex internal surface,  and  adhere there to each other by a
 layer of cineritious substance, called Commissura Mollis.  When
 the brain  is very slightly advanced  in putrefaction,  or  has
 been  made soft by dropsy, this junction scarcely seems to exist
 at all.
   The thalami are medullary on the surface  presented to the
 ventricles of the brain, but within they are a mixture of cineri-
 tious  with medullary matter.   The fibres of the medullary are
very intimately blended with the crura cerebri, and radiate from
within towards the circumference of the brain: some of them
  Vol. II.—32 
362
NERVOUS SYSTEM.
are placed in layers, and are connected with the tubercula quad-
rigemina.

  The Corpora Striata, or the Ganglia Cerebri Antica, also two
in number, one for each  side or hemisphere  of the brain,  are
situated before the thalami  optici, at the bottom  of the lateral
ventricles. They are about two and a half inches long, convex
on their upper surface, and eight lines broad at their front part,
but  taper very gradually to a point  behind.   They are about
four lines apart in front, and are separated there by the septum
lucidum, but their posterior extremities diverge from each other,
so as to admit the thalami optici between them."
  The surface of the corpus striatum is  cineritious, but within
it consists of cineritious and of medullary matter, placed in lay-
ers  which alternate  wilh each  other.  These layers are ar-
ranged in a crescentic  manner, so as to present  the convexity
upwards and the concavity downwards.   The medullary sub-
stance is a continuation of that of the crus cerebri and of the optic
thalamus.  It enters at the posterior inferior part  of the  corpus
striatum, and immediately divides into three layers, placed one
above the other, and of which the two inferior are  more narrow
and short than the superior.  The  upper layer, in its  progress
forwards, is interrupted  by a body of cineritious substance,
which  occasions it to  divide into a multitude of distinct radi-
ated fibres.  The same circumstance attends the other  layers,
but in a  more limited degree.   The medullary  matter  of the
corpus striatum  may then be traced, in  all directions, into the
hemisphere of the brain.   The cineritious substance of the cor-
pus striatum is abundant, and is divided by some anatomists into
two kinds, one of a light gray, and another of a darker colour.
The first forms the middle and inferior part of the corpus stria-
tum : the second is in greater quantity, and is found principally
above and between the two upper layers.  Such  is the general
plan of the structure of the corpus striatum;  but, it should also
be understood, that a  close  intertexture exists between  its me-
dullary  and cineritious matter.
  The most satisfactory way of exposing the structure  of the
corpus striatum, is to scrape off its under surface, in tracing its
medullary matter from the crus of the brain, and through the
optic  thalamus.   It will then be  seen, that the medullary sub- 
THE CEREBRUM.                    363
stance of the crus reaches the posterior inferior part of the cor-
pus striatum, and is immediately invested in the greater part of
its circumference with cineritious matter, it then begins to ex-
pand after the manner of a fan into filaments. These filaments
or fasciculi  penetrate the cineritious matter in various direc-
tions, besides  those  just detailed.  A particular exposition of
them is given by Gall and Spurzheim, in their anatomy of the
brain.

   The Tasnia Striata is placed in the angle formed between the
internal margin  of the Corpus Striatum, and the external one
of the Thalamus Opticus, where  these two bodies are in  con-
tact and continuous  with one  another.  It is a small medullary
band, not a line in breadth, commencing near the anterior cms
of the fornix, with which it is connected frequently by filaments;
and observing  the curved course of the fissure in which  it is
placed, it goes to the posterior end of the corpus  striatum, and
even beyond it in most cases,  by uniting itself to the top of tire
Cornu Ammonis.

   The  Corpus Callosum.  When the fissure between the he-
mispheres of the cerebrum is widely separated, or when the su-
perior part of the hemisphere is cut away  on a level with the
bottom of the fissure, the Corpus Callosum, a medullary layer,
as stated, is brought fully into view.   This  body unites the me-
dullary mass of the  two hemispheres, and  is a large commis-
sure.  It occupies about two-fifths of the long diameter of the
brain, being nearer to its anterior than to its posterior end, and
is about eight lines  broad; increasing, however,  somewhat in
breadth posteriorly.   The lateral half of it, on  either side, is
concealed by the hemisphere  overlapping  it, but is  prevented
from adhering by a horizontal fissure, which extends from one
end  to the other.   It has an  arched form, being convex above
and  concave below.  Its thickness is uniformly about three lines,
with the exception  of  its anterior and its posterior margins,
which are more.   Just above the horizontal fissure there exists
a longitudinal layer of white neurine  running from  one end to
the  other of the  flat surface  of  the hemisphere, described by
Mr. Solly.*
                   * Anatomy of Brain, 1836. 
364
NERVOUS SYSTEM.
  The middle line of its upper surface is marked out from one
end to  the  other by a very slight depression, the  Raphe;  on
each side of which there  is a very small  linear elevation of the
same  extent,  but slightly curved inwards towards its fellow.
From these  longitudinal  lines  there  proceed outwardly  trans-
verse  ones, having a fibrous appearance.  At the anterior and
posterior ends of the corpus  callosum, the  latter  are  some-
what  curved and radiated towards the periphery of the brain.
Other  longitudinal  lines also exist on the surface of the corpus
callosum, but  they are not seen with equal  facility.  The an-
terior extremity of  the corpus  callosum is rounded off, and bent
downwards  towards the  basis of the brain, in such a manner
as to  present  backwards  its  concavity; which thus embraces
the fore part of the corpora striata, and closes the lateral ven-
tricles at this point.  The posterior end of the corpus  callosum
is rounded, also, and continuous with the  fornix and  with the
cornu ammonis.
  By examining the Corpus Callosum from  below,  or by look-
ing at its relative situation and shape on a hemisphere which is
accurately separated from its fellow in  the  middle line, it will
be seen that its lower surface is very concave, being  highly
arched from before  backwards; that  it forms the roof of the la-
teral ventricles, and that  this surface of it is about  two  inches
in its  transverse  diameter, and, therefore, more than twice as
broad as the upper surface.

  The Fornix, (Trigone Cerebral, of  the French) is placed im-
mediately below the corpus callosum.   It is a triangular body
of medullary neurine or  matter, the  base of which is behind
and the apex in front.  It  is about an inch and  a half long in
its body, and one inch wide at  its base.  It  is  the  latter part,
which, lying immediately beneath the posterior end of the cor-
pus eallosum, is continuous with it, and causes the fornix to be
considered as  a part of the same structure with the  corpus cal-
losum.  These two bodies, which may be compared to a sheet
of medullary matter doubled on itself, have their  surfaces  in
contact for  a short  distance behind, the fornix afterwards, by
advancing and keeping itself in close contact with the thalami
nervorum opticorum, which are just below it,  diverges more
and more from the  under surface of the corpus callosum.   It 
THE CEREBRUM.
365
conceals all the upper surface of the thalami except their exter-
nal margins, and, having reached their -anterior extremities, its
apex descends towards the basis of the brain.
   The body of the fornix is about a line thick, but, at  its ante-
rior extremity, it becomes somewhat cylindrical, and is divided
into two columns, called Crura Fornicis Anieriora.  Each of
these crura, in descending adheres to the anterior extremity of
the thalamus of that side, and, getting finally below it into the
floor of the  third ventricle,  it, after a course slightly curved,
joins the  cortical substance of the Eminentias Mammillares.
Santorini, aware  of this junction,  considered  the eminentiae
as a part of the fornix, and, therefore, called  them Bulbi For-
nicis.
   The fornix has other attachments of a more complex descrip-
tion, which the anatomist should attend to, as they  serve to
indicate the modes of intercourse  between the several parts of
the cerebrum.   Its fibres having reached, and  piobably formed,
the eminentiae mammillares,  one  fasciculus of them  ascends
from thence  along the internal  face of the optic  thalamus, in-
vested  by the  cineritious  matter of the  latter, and spreads it-
self above like a fan, and forms the tuberculum anterius: a se-
cond fasciculus  from the same point, having divided into two,
after  going a  short distance, sends one  division backwards
along  the upper internal face of the optic thalamus, to join
the peduncle of  the pineal gland, and  the other division, which
is more anterior, runs to join  the taenia striata;  the third fasci-
culus from the  eminentia  mammillaris,  being covered by the
optic nerve, goes outwards and  backwards to terminate in the
thalamus.
   The posterior margin,, or the base of the fornix, besides run-
ning into the corpus callosum, has the angle on each,side elon-
gated so as to rest upon and to join the upper, end of the cornu,
ammonis.  The angle, being continued, then.follows the wind-
ing course of the latter, adhering to its  posterior margin, but
hanging loosely  over the anterior.   This loose edge or  continu-
ation of the external margin of the fornix is the Taenia Hippo-
campi, or Corpus Fimbriatum of the Lateral  Ventricle.  The
elongations of the posterior angles are called Crura Posteriora
Fornicis.  In the brains of individuals who have suffered from
general dropsy, one frequently finds the fornix  narrower than,
                            32* 
366
NERVOUS SYSTEM.
usual, and in its middle a fissure which separates almost com-
pletely its two halves.
  As the fornix is  fitted to the  upper surface of the optic tha-
lami, it is. of course concave below and  convex above, or re-
sembles a triangular arch resting upon its three points or angles*
Owing to some  misunderstanding of the orignal Greek work
+«>.<<5Vj, which, according  to  the interpretation of  Sabatier,
means a vault, and thereby expresses the whole  body, anato-
mists, with the exception of him,  have generally supposed the
striated under surface of  the fornix to  be meant by it, and
have called the surface Lyra, in which mistake one has followed
another..

  The Septum Lucidum is a partition placed vertically in the
middle line of the brain, and extends from the corpus callosum
above  to* the fornix below.   It is  of a triangular shape, but ir-
regularly so, being much broader before than it is behind, and
having its edges so incurvated as to fit the bodies against which
it is applied.
  The septum, lucidum is formed by two laminas placed side to
side, but not adhering to each other, and  leaving, therefore, an
interval between them, called the Ventriculus Septi, or the fifth
ventricle.  Each of these laminae consists of two layers; the
internal is medullary substance, continuous with  that of the cor-
pus callosum and of the fornix; and the external is a layer of
cineritious substance.  The cavity is about an inch and a half
long by a line  wide, and is narrower in the middle than at either
extremity.   It is lined by a delicate serous membrane, which
becomes manifest when the  halitus that naturally covers its sur-
face is. accumulated into,a body of water.   It is generally sup-
posed to be insulated or completely shut up, yet occasionally it
has been found elongated, in front, towards the  space between
the anterior commissure and the anterior crura fornicis, and to,
communicate there with the third ventricle.*

  The Pineal  Gland  (Glandula Pinealis, Conarium) is placed
beneath the posterior margin of the fornix, upon the superior of
the tubercula quadrigemina, or the nates.  It is an oblong conoi*.
* J. F. Meckel. 
THE CEREERUM.
367
dal body, the long diameter of which is transverse, and amounts
to three or four lines, while  the  short diameter is about three
lines.  These diameters are, however, sometimes reversed:  The
substance of the pineal gland is cineritious and of a reddish co-
lour.  At its inferior part there is a small cavity, sometimes
lined with medullary matter, and the orifice of which looks to-
wards the third ventricle.
  This body is connected to the adjacent parts by several cords.
From its bottom there proceeds, on each side, the long medul-
lary filament, called its peduncle, which runs  along the upper
internal face of the thalamus opticus, and, as observed, joins, or
is continuous with, one  of the filamentous processes from the
Eminentia Mammillaris.  From  its base there proceeds a trans-
verse lamina of medullary matter, called the Posterior Commis-
sure of the  brain, which first advances  forwards, and then re-
cedes, so as to be in some measure doubled on itself.   This la-
mina, at either end, is united to the upper posterior part of the
corresponding optic thalamus, and by its lower margin runs  into
the superior edge of the tubercula quadrigemina.
  Frequently, within the pineal gland, and sometimes on its
surface, there is an accumulation of calcareous matter, the Acer-
vulus Cerebri, that appears about the sixth year of life, and con-
tinues for ever afterwards.  It is variable both in quantity  and
in its mode of concretion, for  sometimes there are only a  few
atoms of grit, scarcely  distinguishable  by the feel; while, on
other occasions, it is collected into a body of irregular shape,
and  more than a  line in diameter.   The pieces of which  the
acervulus consists are sometimes united by cellular substance,
and enclosed in a sac.  The chemical  analysis presents phos-
phate of lime in large proportion, carbonate of lime, and  ani-
mal matter.

  A reflection of pia mater,  called the Velum  Interpositum, se-
parates the pineal gland from the  fornix, and the fornix from
the thalami  nervorum oplicorum.

  The  Tubercula Quadrigemina (or the Nates et  Testes) are
situated on the  superior  face of the crura cerebri, and just be-
hind the thalami nervorum opticorum.   A very complete view
of them is obtained by separating the posterior lobes of the ce- 
368
NERVOUS SYSTEM.
rebrum, and by paring off the vermis superior cerebelli.  Though
the name implies four distinct prominences, yet they are formed
from a common mass of nine or ten lines square, on the poste-
rior surface of which these prominences  arise.  They are in
pairs, and are separated from one another by a crucial depres-
sion.   The largest, or upper pair, is Ihe Nates, the lower pair
the Testes.  The external surface of these "bodies is medullary,
and within they are  cineritious.  From the Nates there pro-
ceeds a considerable medullary fasciculus, which runs forward
to join  the Corpus Geniculatum Internum on the internal pos-
terior face of the thalamus nervi optici; there proceeds also
from them a  second fasciculus, which either joins  the  optic
nerve itself, or the contiguous part of its thalamus.  The Testes
receive, at their lower end, the valve  of the brain;  and there
also proceeds from them a large fasciculus of medullary matter,
which joins  the Corpus Geniculatum  Externum  of the  optic
thalamus..

                Of the Ventricles of the Brain.

   These cavities are four in number:  two, called lateral, are
placed one in either hemisphere of the cerebrum,, a third is be-
tween the  two thalami, and the fourth under the cerebellum.
They  have all been  alluded to, but only incidentally.
   The two Lateral Ventricles (Ventriculi Laterales)  are hori-
zontal cavities, or fissures, of an extremely, irregular shape, in
the very centre of the hemispheres, being the interval between
the diverging and converging filaments of the cerebrum.  They
 are separated from each other only by  the septum lucidum; are
 covered over by  the corpus callosum, and have the fornix, tha-
 lami optici, and corpora striata for a floor..  Each one consists
 in a body  or principal cavity, and^ three processes, called cor-
 nua.  The body  has been sufficiently  described in speaking of
 the parts which  constitute its  parietes;.  but  the processes are
 yet to be considered.

   The Cornua, from their, position, are named Anterior,  Poste-
 rior, and Lateral or Inferior.  The Anterior is a very small
 space between the anterior extremity of the corpus striatum
 and the opposite, surface  of the hemisphere, and has  nothing in 
THE CEREBRUM.
369
it particularly deserving of notice.   The Posterior Cornu ex-
tends from the base of the fornix to the distance of an inch or
more in the substance of the posterior lobe  of  the cerebrum.
Its  cavity is conoidal, somewhat curved, with its convexity
outwards, and of six or seven lines in diameter at its base.  Its
internal side is furnished with an oblong eminence called Hip-
pocampus Minor, or  Ergot, from its resemblance  to  a cock's
spur, but its size and form are somewhat variable.  When this
eminence is cut through transversely, it is easy to  see that it is
formed by a  convolution of the posterior lobe projecting into
the posterior cornu.  The convolution is covered by medullary
matter on the side of the ventricle, and of course by cineritious
on the side of the periphery of the brain, and is the bottom of
an  anfractuosity.

  The Inferior, Middle, or Lateral Cornu, of the  Lateral ven-
tricle is situated in the middle lobe of the cerebrum.  It com-
mences at the posterior angle of the fornix, and winds down-
wards and forwards in a  semicircle towards the fissure of
Sylvius,  presenting its  convexity outwards,  and its concavity
within.  Its floor is furnished in  its whole  length with an ele-
vated ridge,  the  surface  of  which  is semi-cylindrical.  This
ridge is the Cornu Ammonis, or Hippocampus Major, and in-
creases somewhat, both  in breadth and elevation, as it winds
down the process of the ventricle.   Its lower or anterior extre-
mity is terminated by two or three  small tubercles, and is  the
Pes Hippocampi.  Occasionally the Hippocampus  Major is
marked off by a middle longitudinal fissure into two elevations,
of which the  external is the smaller.   On its concave side there
is the thin edge of medullary matter, continuous  with  the  ex-
ternal margin of the fornix.   The extremity of a knife handle
may be insinuated for a short distance between this edge and
the Hippocampus; it ceases about half way down the latter,
and in the natural state of the parts is concealed by the plexus
choroides.   This edge is, as mentioned  in  the  account of the
fornix, the Tasnia Hippocampi or  Corpus  Fimbriatum of the
lateral ventricle.  Beneath the latter, and partially covered by
it, there is another body, which presents itself in the form of  a
small cord of  cineritious matter, is not quite  so long as the
Taenia, and is called Fascia  Dentata, from  being  divided  into 
370                   NERVOUS SYSTEM.

several sections by transverse fissures, which give it an undu*
lated appearance.
  A transverse incision of the Hippocampus Major shows that
it is a body of cineritious matter, covered on its surface by a
thin layer of medullary substance.

  The Third Ventricle, (Veniriculus Tertius.)  When the fornix
is separated from its anterior crura and turned over backwards,
the process of pia mater, -called Velum Interpositum, is found
between it and the optic thalami.  This process is of a triangu-
lar shape, resembling the fornix, and is about the same size; it
is insinuated into its place from  the surface of the brain, under
the posterior margin of the corpus callosum.  Its lateral margins,
which project beyond the corresponding ones of the fornix, are
formed by a congeries of convoluted vessels, constituting the
Plexus Choroides.
  The Plexus Choroides, may be  traced  from the Pes Hippo-
campi along the corpus  fimbriatum  to its position on the mar-
gin of the velum interpositum;  and insinuates itself from the
bottom of the cerebrum between the pons varolii and the con-
volution forming the Hippocampus Major; but when it reaches
the anterior end of the fornix its convoluted character ceases,
and it terminates, on each side, in a single vein, (Vena Galeni,)
which runs from before backwards,  in a straight line, near the
middle  of the  velum interpositum.   The vein, finally,  unites
with its fellow to form a single trunk, which runs into the fourth
sinus of the dura mater.
  This Velum Interpositum, called also Tela Choroidea, adheres
very strongly to the fornix by means of small vessels: it may be
raised with less difficulty from the thalami, though  it serves to
keep the third ventricle closed above, with the exception of the
part just behind the crura of the fornix, where the third and the
lateral ventricle communicate by the foramen of  Monro.  The
pineal gland is entangled in  its posterior part, being placed be-
low it, and is generally torn from its peduncles when the tela is
raised up.  It is at this point that the tunica  arachnoidea may
be traced into the  cavity of  the  lateral ventricles, according to
Bichat.*
  • Some doubts, I have stated before, may be reasonably raised on this point of
anatomy, as the evidence is seldom or never satisfactory to the full extent, and as 
THE CEREBRUM.                     371
  The Plexus Choroides, which was stated to bound the Velum
Interpositum on each side, and to descend along the Hippocam-
pus Major to the fissure of  Sylvius, or rather  to ascend from
this point, and to terminate in the vein on the side of the mid-
dle line of the Velum, is narrow at its termination, but increases
continually in breadth as it is traced towards its commencement.
The middle part, however, where it makes its turn, is an excep-
tion to this rule, for there it is larger in every way than else-
where: its vessels being more capacious and more tortuous. Pre-
cisely  at this point a vesicle  or more  is very frequently found,
considered by some as a hydatid of the brain; in some cases it
is filled  with calcarious matter instead of with water.  The
Glandulas Pacchioni, as stated, also prevail at this margin.
   On  the under surface of the Velum Interpositum, adhering to
it,, there is on each side a small venous plexus which  goes from
before backwards, and terminates in the vena galeni, near its junc-
tion with its fellow.  It receives the blood of the third ventri-
cle.
   There is also the same sort of plexus in the fourth ventricle.
   Upon the removal of the Velum Interpositum, or its elevation,
the whole upper surface of the thalami optici is exposed.  The
third ventricle is  also brought into  view, being placed imme-
diately between the thalami optici.   It is a narrow oblong cavi-
ty, bounded  below by  the  pons tarini, crura cerebri  and the
eminentias mammillares, and  above  by the velum  interposi-
tum, and the fornix.  The anterior crura of the fornix are at its
fore part, and just before them is the anterior commissure (Com-
missura  Anterior.)   This  body is a  transverse  fasciculus of
medullary matter, which  passes from one  hemisphere to the
other through the anterior margins  of the thalami optici.   Its
middle part  is rounded and  free, but  its  extremity  penetrates
on each side into the substance of the anterior  inferior portion
of the corpus striatum, and spreading out gradually, describes
a  curve with its convexity forwards, which terminates in the
Taenia Hippocampi of the inferior cornu of the lateral ventricle.
This fasciculus, in penetrating the corpus striatum, does not  mix
with its substance, but, in the early part of its course, goes in a

such an arrangement would be contradictory to that of the tunica arachnoidea
on the surface of the brain, which never dips into fissures. 
372
NERVOUS SYSTEM.
 canal formed in the latter.   In order to see this arrangement, a
 part of the corpus striatum must be removed.   The  anterior
 commissure resembles a nerve in its structure, as it is surround-
 ed  by a very delicate sheath, and is divided into fasciculi of
 fibres.  It will  now be understood that three commissures are
 found in the third ventricle, the Anterior Commissure—the Pos-
 terior, which is just in front of the Pineal Gland,* and the Soft
 Commissure, being a cineritious adhesion of the Thalami.f
   Just behind and below the anterior commissure, the base of
 the infundibulum opens into the third ventricle; this place is the
 Iter ad Infundibulum.   At the posterior extremity of the third
 ventricle, just below the posterior commissure, which has been
 described as a process of the pineal  gland, the communication
 exists with the fourth  ventricle.  This passage is  the Aqueduct
 of Sylvius, and leads obliquely downwards and backwards un-
 der the valve of the brain.
   The third ventricle communicates freely with the lateral ven-
 tricle through the aperture called the Foramen of Monro, which
 is situated precisely at the place where the plexus choroides ter-
 minates;  that is to say, under the anterior crus of the fornix.
 Doubts have, from time to time, been suggested in  regard to the
 natural existence of this communication; it only requires a mo-
 derate degree of accurate observation to dispel them: they have
 arisen, probably, from  the aperture being shut up  by the occa-
 sional  adhesion of the  plexus choroides to the contiguous sur-
 face of the brain.

   The Fourth Ventricle (Ventriculus  Quartus, Cerebelli) has
 been, in a great degree, described in the account of the neigh-
 bouring parts; it will, therefore, be very readily understood on
 the present occasion.  It is an  irregular triangular cavity, the
base of which is downwards.   It is bounded in front by the tuber
annulare, and the medulla oblongata, behind by the fundamental
portion of the cerebellum, and above by the valve of the brain
and the tubercula quadrigemina; it is under the latter that the
communication between it and the third ventricle is found.   Its
lateral parietes are formed  by the medullary prolongations from
the cerebellum to the tubercula quadrigemina.  This cavity, as
* See Pineal Gland.
t See Thalami. 
NERVES OF THE ENCEPHALON.
373
stated, is open below, when that portion of pia mater is removed,
which passes from the cerebellum to the medulla oblongata.
   From what  has now been said of the connexion  of the pia
mater with the ventricles, it will be understood that as their sur-
faces are covered by pia mater, and the  removal of it exposes
their cavities,  they are, in fact, continuations of the external
surface of the brain.*


        SECT. VI.--OF THE NERVES OF THE ENCEPHALON.f

   These nerves are designated  numerically, from before back-
wards, and, also, by some peculiarity of distribution or function.
This numerical arrangement is the most sanctioned by age and
general admission, it is not, however, so  unexceptionable  as to
avqid all objections to it;  improvements have therefore been sug-
gested from various quarters, founded on particular anatomical or
physiological convictions; but the improvements themselves are
exposed to objections as strong as the ancient nomenclature.  For
example, the innovators are not agreed in regard to the proper
number of nerves, nor on those which should be considered dis-
tinct from each other.  Some do not consider the olfactory as a
nerve, but only a ganglion ; some consider the glosso pharyngeal
and par vagum as but one nerve, while others speak of them  as
two. Some make but one nerve of the third and sixth, owing to
their common  distribution to the muscles of the eye.   It is evi-
dently expedient under these  circumstances, to escape a farrago
of opinions,  by adhering to the most received classification, at
least, till the ground of  change  be  better explored  and  more
universally acknowledged.  If there be any thing of incalculable
importance to  the comfort of students and scientific  men gene-
rally, it is  uniformity of language, or rather conformity to a re-

  * In Williams the murderer, examined immediately after his execution, Au-
gust 9,1839, the encephalo spinal fluid, amounting to from two to three drachms,
came out clear and abundant from the fourth ventricle; on cutting through the tu-
nica arachnoidea which bounds it below.
  t The more improved observations of modern anatomists having pointed out
the fallacy of considering the brain as the source of the spinal marrow, instead of
the reverse; it follows, that the proper order of describing the nerves of the en-
cephalon, is successively from the spinal marrow.  I had adopted this plan, for-
merly, but certain considerations of facility in study, have induced me to abandon
it after some years of experience.
   Vol. II.—33 
374
NERVOUS SYSTEM.
ceived standard of nomenclature.  The only justifiable departure
from this rule, is where something new has been actually disco-
vered, a necessity of course then exists for giving a new name
as it would not do to take the appropriated name of any thing
else.

   The Olfactory Nerve or First Pair (Nervus Olfactorius, Par
Primum,) is situated on the under surface of  the anterior lobes
of the brain, near the fissure that separates the hemispheres.   It
goes forwards  from its  root, and also converges gradually to-
wards its fellow, so as to reach the cribriform plate of the eth-
moid bone, through the perforations of which it passes out.
In its course, it is lodged in a small furrow of the cerebrum, by
which pressure upon it is prevented.
   This nerve arises by three  medullary fasciculi, or roots, from
the basis of the brain at the corpus  striatum, in the fissure of
Sylvius, where the anterior and middle lobes join each other:
these roots are from eight to twelve lines on the outer side  of
the infundibulum.  The roots are placed, in regard to each other
diverging;  one is within, another  in the  middle, and the third
external.   The external root is the longest, and  arises from the
extreme posterior margin of the anterior lobe by its last convo-
lution; being connected with the middle lobe, and also with the
anterior commissure.  It has a curved course from without in-
wards, the concavity of which is forwards, and the convexity
backwards.  The internal root is concealed  by the chiasm of
the optic  nerves, and  arises from  the  adjacent surface of the
anterior lobe.   The middle root comes from the posterior mar-
gin of the anterior lobe by the cribriform surface, which is be-
tween the  other  two roots.   These  origins, emanating from
the cortical substance, unite to form a single prismatic cord,
which increases in size as it advances  forwards, and consists
of  medullary  and  cineritious  longitudinal  fibres mixed  to-
gether.
  The anterior extremity of  the olfactory nerve is swollen out
into what is called  the Bulb,* (Bulbus,) and sends from its un-

  * Many anatomists consider this as a ganglion, from its extreme development
in the sheep, bullock, horse, vtc, and, therefore, call it the Olfactory Ganglion.
Rolando.  Solly on the Brain. 
                 NERVES OF THE ENCEPHALON.              375

der surface filaments, which,  surrounding themselves with a
tunic from the dura mater, penetrate into  the nose, and spread
themselves  on  the  Schneiderian  membrane.   In its  whole
length  it js  exceedingly soft and  pulpy, till  it gets out  of the
cranium.

  The Optic Nerve or Second Pair (Nervus Opticus, Par Se-
cundum) is about the same size with the trigeminus.   It arises
by a broad flattened root, one portion of which comes from the
posterior end of the  thalamus opticus, and another  from the
testis through the means of a medullary band that passes  from
the latter towards the thalamus of the  same side.  From this
point the  optic  nerve winds  forwards under the crus cerebri,
adhering to it and forming a  connexion  with the tuber cine-
reum,  and then  inclining inwards towards its fellow. Its ad-
hesion to the crus is considered by many anatomists as another
of its origins.
  The Optic Nerve, having  reached the under anterior paft
of the third ventricle, adheres so closely to its fellow that the
two seem fused together, in such  a way that there is no line of
separation between them.  This junction  receives, above,  from
the third  ventricle,  some medullary filaments, which Meckel
feels authorized to consider as another origin.   The junction
presents the form of the letter X, and is  called  the chiasm  or
crossing of the  optic nerves.   The  most distinguished anato-
mists,  however, have laboured in vain to settle  the question of
the mode  of junction; some believing that there  was only  a la-
teral union, others that  the nerve of one side crossed over to
the other side, and others, again,  that the decussation  occurred
only with  some of  the  fibres, but not all.  Observations,  in
comparative anatomy, on blindness, and indeed  on every  con-
ceived mode of elucidation,  have  been resorted  to without
producing  a solution  of the  problem; but  the discussion  of
their  merits would  require too  much  space for the present
work.*
  The Optic Nerves as they approach  their chiasm become
more cylindrical, and, continuing so afterwards, penetrate into

  * Mr, Mayo, of London, considers the posterior part of the  junction as formed
of fibres, making a curve, the  convexity of which is forwards; it is said to be
very distinct in the mole, which has no other optic nerve. 
376                   NERVOUS SYSTEM.
 the orbits through the foramina  optica.  It is only in front of
 their junction  that they are invested  by a neurileme; which,
 having considerable firmness, penetrates into their interior, and
 divides them into distinct canals.

   The Nervus Motor Oculi, or Third Pair (Par  Tertium,)
 arises from the internal face of the crus cerebri, about two lines
 in advance of the anterior margin of the tuber annulare.  Its
 roots come, in great part, from the cineritious matter which is
 found on the surface of the crus, and  may be traced for some
 distance upwards and  backwards along the parietes of the third
 ventricle.   The nerves of the opposite sides are in contact for
 some distance  by the  internal faces of  their roots, but do not
 adhere.*
   The Nervus Motor Oculi proceeds  from its origin  towards
 the external margin of the cavernous sinus, and, penetrating into
 the orbit through the sphenoidal foramen, it is distributed to most
 of the muscles of the eye-ball.

   The Pathetic Nerve, or Fourth Pair (Nervus Patheticus, Par
 Cerebrate Quarlum,)  is the smallest which comes from the en-
 cephalon, and is not larger than a sewing thread.   It arises by
 two filaments, or roots, from the upper anterior  face of the
 valve of the  brain, just below the testes.   This origin is soft,
 and easily  broken, from the want of a neurileme; but the latter
 is soon afterwards furnished.
   The Nervus Patheticus appears on the base of the brain, be-
 tween the cerebellum and  the  posterior lobes of the cerebrum,
 at the external margin of the tuber annulare.  It then  goes for
 some distance along the margin of the tentorium till it comes
 near the posterior clinoid process: it then penetrates into a ca-
 nal of the dura mater, and reaches the orbit of the eye through
 the sphenoidal foramen, to be distributed on the superior oblique
 muscle.

  The Nervus  Trigeminus, or Fifth pair, also called  Trifacial,

  * Mr. Solly considers this  nerve to arise from  the interior of the pons, and to
be connected with the valve  of Vieussens by some fibres, from the latter going
into the crus cerebri. 
NERVES OF THE ENCEPHALON.
377
{Par Quintum) is one of the largest among those that proceed
from the basis of the brain, and emerges from the side of the
pons varolii, just where it is continuous with the crus cerebelli.
It is composed of three roots: an anterior, a posterior, and a
middle;*  of which the latter is much the largest.
   The middle root is about a line and a half in breadth, and has
a passage made for it by the very obvious splitting of the super-
ficial fibres of the pons varolii. It is composed of thirty or forty
fasciculi, which are divisible into  a hundred  or more fibres.
These fasciculi may be traced into the substance of the  Pons
Varolii, (but  intersected by the transverse fibres of the  latter,)
in the direction of the  fourth ventricle.  When they have  come
near the latter, they may be traced thence into the medulla ob-
longata, towards  the fissure that exists between the  corpus oli-
vare and  restiforme.   It is at this point,  that the greater  num-
ber of the fibres arise; some from the corpus olivare, and others
from the fissure.
   The commencement of this root is pulpy and destitute of fila-
ments, and is surrounded by grayish  substance; but when  it has
advanced into the pons, it is surrounded by a  fine membrane,
and  is  very evidently filamentous.   There  is a successive  in-
crease in its size,  from its commencement till it is ready to
emerge from the  pons, when it becomes  somewhat contracted,
and  immediately  afterwards  increases again considerably in
size.  It then enters a canal of the dura mater at the fore part
of the petrous portion  of the temporal bone,  and just behind the
cavernous sinus.   This canal sets but loosely about it at first,
but afterwards it  adheres to the surface of the nerve.
   The middle root of  the nervus trigeminus, in the  upper part
of the canal of the dura  mater,  preserves its fasciculated ap-
pearance, and many small filaments are interchanged between
the fasciculi,  so as to make a complex net-work.  But, at the
lower part of this canal,  it is  converted into a  ganglion of a
semi-lunar shape, with its concavity upwards, being about  six
or eight lines in length, and one and a half in breadth.  This  body,
called the Ganglion of Gasser,  (Ganglion Semi-lunare,  Plexus
Gangliforrnis,)  is  compact, and has its fibres very much matted

  * Santorini, Observ. Anat. Venitia, 1724.  Soemmering, de Corp. Hum. Fab-
rica, tom. iv.  Gall and Spurzheim, Anat. du Cerv.
                            33* 
378                   NERVOUS SYSTEM.
above, but below they assemble into larger  and more distinct
fasciculi, which  are  afterwards  arranged into three principal
trunks, departing from the cranium through different foramina;
to wit: through the sphenoidal foramen, the foramen rotundum,
and the foramen ovale.
   J. F. Meckel asserts that the filaments of the plexus above the
ganglion, for  the most part terminate in a  gutter formed in the
superior  margin of the ganglion, and that there are but very
few of them  which can be traced into the trunks below.   The
trunks below, consequently, arise from the circumference of the
ganglion.
   The two smaller roots of the nervus trigeminus proceed out
of the tuber  annulare at different  points, from that of the large
root, and each one  has its appropriate fissure for that purpose.
One,  from its situation,  is, as stated, called Anterior, and  the
other Posterior.   Each may be traced into the posterior chord
of the medulla oblongata, but not  so  far as  the large middle
root,  and  is  formed  by several fasciculi  of medullary fibres.
The anterior and  posterior root, after going  separately for six
or eight lines, unite to form a single chord.*  This chord  does
not  merge itself  in  the  semi-lunar  ganglion,  but  continues
distinct from  it,f with the exception of sending  off to it a few
fasciculi; and it sometimes has its own distinct canal, and aper-
ture  in the dura mater for passing  through  it;  it afterwards gets
from the cranium through the foramen ovale,  and is distributed
to some of the muscles of mastication, as the temporal and buc-
cinator.
   The general distribution of the' fifth pair of nerves, or the
trigeminus, is to the orbit, to  the face, and to the tongue.

  The Motor Externus Oculi, or  Sixth  Pair of Nerves (Par
Sextum)  arises from the base or upper extremity of the corpus
pyramidale, under the posterior margin of the tuber annulare
or Pons: when the latter is  broader than usual, some of the
fibres seem to come from it;  but the appearance is deceptious,
as they only  penetrate it.   The fibres  are  assembled into two

  * These two constitute what is called the motory part of the fifth nerve.  Mr
Solly considers it to arise from the valve of the brain near its root.  p. 249.
  f In this  respect the fifth pair resembles one of the spinal nerves.. 
NERVES OF THE ENCEPHALON.
379
roots, of which the internal is three or four times as large as
the other.
  These roots, before they penetrate the dura mater, most com-
monly unite into a single trunk, which goes almost directly for-
wards, and is enveloped in  a neurileme.  Passing through the
cavernous sinus, it gets into the orbit by the sphenoidal fora-
men, and is spent  upon the abductor oculi muscle.

  The Seventh Pair of Nerves is composed of the Facial and
the Auditory.
  The Facial Nerve (Nervus Facialis, Portio  Dura Septimi,
Par Septimum) is placed in front of and above the auditory
nerve.  It  arises  by two branches, which are perfectly distinct
from each other,  and  differ much  in their  size.  The larger
one, which is placed within and above the other, arises from
the medulla oblongata  at the most superior part of the corpus
restiforme, where the latter joins  the tuber annulare.  The
origin of the  nerve  is  sometimes overlapped by the latter, so
that some few of  its fibres appear to  come  from the annular
protuberance, while they only pass  through  it, in their course
from  the  medulla oblongata.  The second  branch, which is
much smaller than the other, arises, by three or four filaments,
from that portion  of the medulla oblongata which is placed be-
tween the first branch  and the auditory nerve.
  The two branches of the facial  nerve  are kept distinct for
the distance  of several lines  before they unite.  Proceeding
outwards and backwards, they reach the  meatus auditorius in-
ternus, and then proceed, as a single cylindrical trunk, through
the aqueduct  of Fallopius, to emerge at the stylo-mastoid fora-
men, for the purpose of being distributed upon the muscles and
skin of the  head.

  The Auditory  Nerve (Nervus Auditorius, Acusticus, Portio
Mollis Septimi)  arises, in part, from the medullary strias on the
surface of  the calamus scriptorius, and partly from the corpus
restiforme, between the glossopharyngeal nerve and the tuber
annulare.   At its origin it is so extremely soft as not to bear
handling, and is too pulpy to present the appearance of fibres;
but, becoming more distant from  the medulla oblongata, it is
harder and more  fibrous* 
380                   NERVOUS SYSTEM.
   This nerve is impressed on its internal face by a longitudinal
 furrow for the reception of the facial nerve.   It passes oblique-
 ly forwards and outwards beneath the crus cerebelli, and pene-
 trates into the meatus  auditorius internus.   It  adheres some-
 what near its root to the under anterior margin  of the cere-
 bellum, just behind the crus of the latter: the circumstance is
 considered by J. F. Meckel, as a  proof of its having there ano-
 ther origin, whereby an analogy  is established  between it and
 the two other nerves of  the senses; to wit, the optic and the
 olfactory.
   The distribution of this nerve is confined to the labyrinth of
 the ear.

   The Eighth Pair of Nerves is composed of the Glosso-Pharyn-
 geal, the Pneumogastric and the Spinal Accessory.*
   The Glosso-Pharyngeal Nerve (Nervus Glosso-Pharyngeus, of
 Eighth Pair,) arises from the posterior cord  of the medulla ob-
 longata, just above, and somewhat anterior to  the superior fila-
 ments of the next nerve, with which it is very closely connected.
 Its filaments, which are five or six in number, spring, therefore,
 from the anterior  margin of the  corpus  restiforme, or from the
 fissure separating it from the corpus olivare,t  under the posterior
 margin of the tuber annulare.
   Its filaments soon collect into a round cord, and  anastamose,
 even  in the cavity of the  cranium,  by a considerable  branch
 with  the  pneumogastric.   It runs outwards and backwards  to
 the foramen lacerum posterius, and goes through the same divi-
 sion of it that  the  pneumogastric does, but in its own  canal of
 the dura mater.  About half an inch from this canal it enlarges
 within the cranium, into a small  oblong  ganglion of five or six
 lines long, which extends itself as far as the foramen  lacerum. J
   Its  general distribution is to the tongue  and to the pharynx,
 as its  name implies.

  * For an interesting course of experiments on the eighth pair, by John Reid, M.
D., see Essays on Physiology, Phila., 1838, from the Edinburgh Med. and Su'rgi.
cal Journal.
  t The Corpus Olivare is considered by Mr. Solly as its origin.
  X This ganglion is described by Andersech and by Huber, but its existence is
questioned by Bichat^ 
NERVES OF THE ENCEPHALON.
381
  The Pneumogastric Nerve (Nervus Pneumogasiricus or Vagus,
of Eighth Pair,) arises from the corpus restiforme of the medulla
oblongata, just behind, or on the borders of the fissure separating
it from the corpus olivare, somewhat above, and posterior to the
highest root of  the  accessory nerve.   It commences by a num-
ber of parallel filaments, varying in number from ten to fifteen,
which are placed very near each  other, so  as  to form two or
three flattened fasciculi of half an inch or more  in length.  The
fasciculi below adhere to the spinal accessory, and those above
to the glosso-pharyngeal  nerve.   The  fasciculi, finally, collect
into a single flattened cord of one and a half lines in breadth..
  This cord goes outwards  and backwards to the foramen lace-
rum posterius, and gets through it in front of the internal jugular
vein, being separated from the latter by the  small spine which
arises from the pars petrosa of the temporal bone.  It passes
through its own canal in the dura mater, being thus kept distinct
from the  glosso-pharyngeal, and from the accessory nerve, and
in this canal the fasciculi which form it are collected into a single
cylindrical trunk.   After  getting  through the canal it then  ad-
heres, by a close, strong, cellular substance, to the glosso-pharyn-
geal and to the accessory.
  The general plan of  distribution of the pneumogastric nerve
is, as its name  implies, to the organs of respiration, and to  the
stomach.

  The Accessory Nerve (Nervus Accessorius, of Eighth  Pair,)
arises from the posterior fasciculus of the medulla oblongata, just
behind the nervus hypoglossus, and also from the posterior fasci-
culus of the medulla spinalis, sometimes  as low down as  the
seventh cervical nerve.   There are six or seven roots from the
medulla  spinalis, and about three or four from the  medulla  ob-
longata:  the former are single, and run, successively, into  the
same trunk; but the latter are each composed of two branches,
consisting respectively  of two or more filaments.   These roots
are, successively, larger and longer, as they ascend to join  the
common trunk.   The latter goes up between the posterior fasci-
culi of spinal nerves and the ligamentum denticulatum, and gets
into  the  cavity of the cranium, behind the  vertebral artery,
through  the foramen magnum occipitis.  It is joined sometimes 
382
NERVOUS SYSTEM.
by a sort of knot to the posterior fasciculi, or root of the first and
second cervical nerves; this knot seems  to be neither  after the
fashion of ganglion or plexus, but is peculiar, and looks some-
what as if one nerve was wrapped around the other.
  This  nerve varies  in respect to the  number of its roots, and
the mode of their origin.  In all cases, the trunk, thus formed,
passes from the cranium through the foramen lacerum posterius,
traversing there the dura mater, either  in a sheath common to it
and to the pneumo-gastric nerve, or in  its own particular open-
ing behind that of the latter.
  Its general distribution is to the  muscles and to the integu-
ments of the  neck.

  The Hypoglossal Nerve, (Nervus Hypoglossus, or Ninth Pair,)
arises from the medulla  oblongata, by several  fasciculi placed
one above the other.   The roots of these fasciculi spring from
the fissure which separates the corpus  pyramidale from the cor-
pus olivare, being traced to that  surface of the  corpus pyrami-
dale. The fasciculi are from four to eight in  number, being sub-
ject to  vary  in  different  individuals.  They unite into two or
three trunks, which  coalesce into one,  after penetrating the dura
mater by distinct openings; and then proceed through the ante-
rior condyloid foramen of the occipital bone.
   The general distribution of this nerve is to the muscles of the
tongue.

           SECT. VII.--OF THE ARTERIES OF THE BRAIN.

   The  arteries of the  brain, or pia mater, are derived from  the
two internal carotids, and from the two vertebrals.

   The,Internal Carotid Artery (Carotis Interna) gets into the ca-
vity  of the cranium through the carotid canal  of the temporal
bone, conforming itself of course to the curvature of this canal,
 and is brought by it to  the  posterior part of the body of the
 sphenoidal bone.  In escaping from the petrous bone it has to
 ascend, and  also to  advance somewhat, by which  it is brought
 to  the posterior part of the  sella turcica.   From this point it
 goes horizontally forwards through the cavernous  sinus;  and,
 reaching its  fore part, it then ascends  again, and towards the fis- 
ARTERIES OF THE BRAIN.
383
sure of Sylvius.   While  in the carotid canal, it gives a small
branch to the tympanum of the ear, and as it lies on the side of
the sella turcica it gives off the anterior and the posterior arte-
ry of the cavernous sinus.   When it reaches the anterior cli-
noid process it sends off a large branch, through the optic fora-
men, to the parts contained within the  orbit of  the eye.   This
branch is the ophthalmic artery, and what remains of the inter-
nal carotid is then distributed to the brain after the following
order:

   There are, first of all, some small branches sent to the  adja-
cent parts;  as  the pituitary  gland, the  infundibulum, and  the
lower part of the third ventricle.
   The Arteria Communicans Posterior is directed backwards
and inwards, and runs into the corresponding trunk of the basi-
lar artery, called the posterior cerebral.  There are some varie-
ties in regard to the size and precise point of origin of this trunk,
which it would be needless  to mention  particularly.  Besides
the important anastomosis formed by it, it detaches  several ra-
muscles to the adjacent parts of the pia mater.
   The Arteria  Choroidea is  the next branch from the internal
carotid.  It goes outwards and  backwards, and after detaching
some minor branches, it penetrates into the inferior cornu of the
lateral ventricle, by the side  of the Pons Varolii, and expends
itself  in ramifications upon the plexus choroides.
   The Arteria Callosa, or Anterior Cerebri,  is  detached from
the internal carotid, opposite the last.  It advances  in front of
the union of  the  optic  nerves, converging rapidly at the  same
time towards its fellow.   Just before the chiasm  of the  optic
nerves, a transverse branch  passes between  it  and  its fellow.
This branch, the Arteria Communicans Anterior, is of variable
length  and size in different subjects, being sometimes a line, and
on other occasions three or four lines long.
   The arteria callosa then keeps  near its fellow on the under
surface of the hemisphere, giving out small branches; and having
got on a line with the anterior margin of the corpus callosum, it
ascends on the flat side of the hemisphere, and divides into  an-
terior and into  posterior twigs.   The former supply the fore
flat part of the hemisphere; the latter,  the corpus callosum and 
384                   NERVOUS SYSTEM.

the adjacent  surface of the brain.  These several branches of
the arteria anterior reach as far as the upper convex surface of
the brain, and there anastomose with other arteries.
   The Internal Carotid may now be considered to have lost its
name, and the trunk is continued as Arteria Media Cerebri.   It
is directed outwards,  and engages  in  the  fissure  of  Sylvius;
while there it detaches a great number of branches to the ad-
joining surfaces of the anterior and of the middle lobe.  Some
of these  branches are  of considerable  magnitude, and winding
along the convolutions of the brain, they at length ascend to the
upper surface  of the  hemisphere, and anastomose  with the
branches of the anterior and of the posterior cerebral  artery.

   The Vertebral Artery  (Arteria Vertebralis) is a branch  of the
subclavian.  In order to reach the cavity of the cranium  it
has to traverse the foramina of  the transverse processes of the
six upper vertebras of  the neck.  It  ascends in  a straight line
till it reaches the second vertebra, but there, in  order to pass
through  the  transverse process, it takes a direction  upwards
and  outwards.   It then  ascends vertically again till  it has
passed through the transverse  process of the  first  vertebra.
After which  it  takes  a horizontal course, winding  around the
posterior face of the upper oblique process  of the  same verte-
bra, in a depression for the purpose, and having reached the
internal extremity of this process, it ascends upwards and in-
wards through  the occipital foramen into the cavity of the cra-
nium, perforating the dura mater just above the condyle  of the
occipital bone.   Having  got into the cranium, it  is first on the
side and then on  the  under surface of the medulla oblongata,
and continues to approach its fellow till it reaches the posterior
margin of the tuber annulare.  At  this point the two  verte-
bral arteries  coalesce,  and from their union  results the basilar
artery.
  The vertebral artery in this course, from its origin to its ter-
mination, detaches several arterioles to the heads of the adjoin-
ing muscles, to the membranes of the spinal marrow, and to the
nerves as they come out of the  intervertebral foramina: they
are generally too small and  irregular to deserve  a special de-
scription.  At its  upper extremity, however, it sends off three 
ARTERIES OF THE BRAIN.
385
 branches of some consequence:  the Spinalis Posterior, the Spi-
 nalis Anterior,* and the Inferior Cerebelli.
   The  Arteria  Inferior Cerebelli divides shortly after its  ori-
 gin, or otherwise is double  from  the beginning.  The most pos-
 terior trunk is distributed about the bottom of the fourth ven-
 tricle, on the  fundamental portion  of the cerebellum, and  the
 contiguous faces of the two hemispheres or lobes of the latter.
 The other trunk of this artery is distributed on the under sur-
 face of the cerebellum.

   The Basilar Artery (Arteria Basilaris) is on the middle line
 of the tuber annulare, and extends from its posterior to its an-
 terior margin.   In this course it  detaches some arterioles to the
 tuber; others to the  meatus  auditorius internus, (Arteriae Audi-
 tivae Internae,)  which are spent upon the labyrinth, and anasto-
 mose with twigs from the internal and external carotids.   At its
 anterior extremity it detaches on each  side two  considerable
 trunks;  first the superior artery of the cerebellum, and imme-
 diately afterwards the posterior artery of the cerebrum.
   The Arteria Superior Cerebelli goes  outwardly from  its ori-
 gin just  behind the anterior edge of the tuber annulare, until it
 gains the front margin of the cerebellum.  It  then divides into
 several branches, some of which are distributed on  the upper
 surface of the cerebellum and run to its posterior margin, where
 they  anastomose  with  the  branches  of the  arteria inferior:
 others are spent upon the substance of the cerebellum near its
 anterior edge.

   The Posterior Artery of the Cerebrum, (Arteria Cerebri Pos-
 terior,) one on each side, is the termination of the basilar artery.
 It proceeds abruptly outwards, and  has  gone  but a  few lines
 when it receives the arteria communicans posterior of the inter-
 nal carotid.  It then continues outwardly parallel with the an-
 terior  margin of the tuber annulare, and near it crosses the crus
 cerebri, and is then distributed, on the inferior  and on the pos-
 terior part of the hemisphere and of the corpus callosum.   As
 mentioned, its  branches anastomose with those of the anterior
and of the middle artery of the cerebrum.

                 * See Arteries of Medulla Spinalis,
  Vol. II.—34 
386                   NERVOUS SYSTEM.

  It will now be understood, that an arterial circle or  link en-
closes the chiasm of the optic nerves and the corpora  albican-
tia.  The fore and lateral parts of the circle are formed by the
internal  carotids  and  their  branches; while the hind part is
formed by the Basilar  Artery and its bifurcation.  This  is the
circle of Willis, and establishes a very free  communication be-
tween the vessels of the two sides of the brain.
  The veins of the Brain have been  sufficiently alluded to in
the account of the Pia Mater, and of the sinuses of the Dura
Mater. 
BOOK  IX.
                       PART III.

                          Senses.

  To the  peripheral portion of the nervous  system, belong all
the nerves which are sent off from the Medulla  Spinalis and
Encephalon, as well as the Sympathetic.   Some of these nerves
have a special apparatus attached to their external extremities,
for the purpose of augmenting and facilitating their appropri-
ate powers of sensation; of this class  are  the Olfactory, the
Optic, and the Auditory.  Others of them, as the nerves of the
tongue and of the skin, though they  are the means of special
sensations, yet the apparatus upon which they are  spread is ap-
plied  to many purposes, more striking and useful,  than that of
indicating the presence of surrounding bodies.  And, lastly, the
remaining nerves, being by far the most numerous and large,
are distributed to the muscles and to the viscera.
                     CHAPTER  I.


        OF THE ORGAN OF SMELLING, OR THE NOSE.

  The senses of Vision and Hearing are so insulated in their
offices, that there can be no doubt of the propriety of consider-
ing them as belonging to the peripheral  portion of the nervous 
388
NERVOUS SYSTEM.
system: but the nose being, in the human subject, though not in
all animals, associated with the function of respiration, its allo-
cation is less exceptionable.   Without  detailing the considera-
tions which have  induced  me to put its description under this
head, I will only mention that I have been  principally actuated
by its office of smelling and by its position.
  In' common language, the term nose  is applied  to the part of
the organ of smelling which manifests  itself externally; but  a
very extensive cavity of the same vertical diameter, and divided
into  two  equal compartments,  exists  behind it, the  form of
which has been  described in  the account of the bones of the
nose.   This cavity extends from the bottom of the cranium to
the roof of the mouth, and backwards  to within  an inch and a
quarter of the vertebrae of the  neck.   The nose, externally, is
generally  pyramidal, and has its base below; what is technically
called the root of the  nose is  the part contiguous to the fore-
head.  The base, on each side, is marked  from  the cheek, by
a semicircular depression; which becoming more and more
shallow at its upper extremity, and  increasing its  breadth, is
insensibly lost upon the side and point of the nose.  The ala
nasi is the swell of the posterior part of the base, being bound-
ed behind by the above depression.  The base of the nose offers
on each  side an  oblong oval  orifice, looking downwards  and
having its long diameter forwards and slightly inwards.  These
openings are commonly about two lines below the floor of the
nose, but there is  a diversity in this respect.

  The Nasus Cartilagineus, or  the cartilaginous portion of the
nose, is  placed wholly at  its anterior extremity, and serves to
elongate  the cavity in that direction.   It  presents a  vertical
cartilage,  which  is in continuation  of the bony septum: on
each side of this, there is an  oval  cartilage, and behind  and
below the latter, several distinct and small pieces of cartilage,
which preserve the form of the alae nasi, and constitute  their
foundation.
  The Vertical Cartilage, or Cartilaginous  Septum (Septum
Cartilagineum) is placed  in  the middle line of the nose, and
has its anterior angle projecting beyond the bony orifice of the
anterior nares.   Occasionally,  from a faulty conformation, it
inclines more to one side than to the other.  It adheres, by its 
ORGAN OF SMELLING.
389
superior margin, to the nasal lamella of the ethmoid and to the
middle nasal suture, and  behind to the anterior margin of the
vomer.   The inferior margin is free in the  greater part of its
extent, but adheres behind to the suture between the maxillary
bones.   The anterior margin sends out, on each side, a trian-
gular plate, the upper edge  of which adheres to  the  inferior
margin of the nasal bone, and of the nasal process of the upper
maxillary.   These plates form the upper part of the cartilagi-
nous nose, and from their ligamentous attachment to the bones,
admit of a slight motion from side  to side.
   The Oval Cartilages, one on  each side, are a species of semi-
elliptical ring, deficient or open at their posterior end.   The
external side of the ring, is an oblong oval plate,  which is di-
rected upwards and backwards.   The internal  half of the  ring
is much  narrower, and proceeds backwards from the preceding
part at a very acute  angle: its superior margin is in  contact
with the septum cartilagineum; itsjnferior margin  reaches be-
low the latter, and its anterior  extremity is in  contact with its
fellow, owing to the cartilaginous septum not reaching so far
forwards.   The place of contact of the two oval cartilages to
each other, forms the-tip of the nose and the Columna Nasi, and
gives the apparent thickness,  before dissection, to the lower
part of the septum narium.
   The Ala? Nasi, or the convexities on each side of the base
of the nose, it has  been said, owe  their shape to the presence
of several small pieces of cartilage, whose form, size, and num-
ber are  too variable to admit of a  standard description: occa-
sionally they are all collected into but one cartilage.  They serve
a  similar purpose with the  oval cartilage, and with  it  are  the
means by which the orifice of the nostril is kept patulous.  They
are deposited in, and held together l>y a  ligamentous membrane.
This membrane  attaches  them to the lateral margin of the an-
terior bony  naris, and also  unites the upper edge of the  ex-
ternal plate of the oval cartilage to the inferior margin of  the
triangular plate of the cartilaginous septum.  It is the length
and looseness of this  ligament which permit such  free motion
to the end of the nose.   In  addition there exists a small liga-
ment described'by Caldani, which  goes from the posterior  end
of the columna nasi to the anterior inferior margin  of the bony
nares.
                            34* 
390
NERVOUS SYSTEM.
  The skin which covers the  upper half of the nose is loosely
attached, by cellular substance, to the  subjacent parts, but it
adheres very closely to the surface of the cartilaginous and li-
gamentous structure, and is abundantly furnished  with  seba-
ceous glands^and follicles.  The exterior orifices of the latter
are apparent, and are often filled with their appropriate fluid in
an inspissated state, which, when forced  out by pressure, as-
sumes the form of  small worms, the  blackness of the  end of
which is only dirt.
   There are several muscles destined to move the cartilaginous
structure of the nose, and which have been described among
those belonging to the face.   They are,
   The Levator Labii Superioris Alaeque Nasi, which lies upon
the side of the nose and  comes from  the  superior part  of the
nasal process and body of the upper maxillary bone, is, besides
its insertion into the upper lip, connected with the ala nasi, and
will draw the latter upwards:—
   The Compressor Naris, arising from the ala nasi by a small
pointed beginning,  is spread  out upon the upper  edge  of the
oval cartilage and upon the triangular plate of the cartilaginous
septum, so as to cover it, and  is inserted into its fellow  on the
middle line:—
   The Depressor Labii Superioris Alagque Nasi, by arising from
the  roots of  the alveolar processes of the incisor  and  canine
teeth of the upper jaw, and going  to be  inserted  into the ala
nasi, as well as into the upper lip, will draw the ala nasi down-
wards :—
   The Nasalis Labii Superioris, or Depressor Narium, which
 is the pointed production from the  orbicularis oris, going into
 the columna nasi, and  will draw  the latter  downwards and
 backwards.

   The Mucous Membrane of the Nose (Membrana Pituitaria,
 Schneideriana)  lines the whole of each side of the nose, pene-
 trates into the several sinuses and cavities communicating with
 it, and  is continuous, at the orifice of the  nostrils, with the
 skin, and at the posterior nares, with the mucous membrane of
 the pharynx.
    It is not of essential importance to trace its course from any
 particular point, but for the sake of perspicuity, we may begin 
ORGAN OF SMELLING.
391
at the floor of the  nostril, which it covers in  a smooth even
manner.   From this it ascends on the septum narium, which it
covers also smoothly without forming any fold or duplicature,
and adheres so loosely that it may be detached with great fa-
cility.   Behind, it  covers the body of the sphenoid bone, and
lines its cell; in front, it covers smoothly the os nasi and nasal
process of the upper maxillary bone, and also the cartilaginous
nose.   Above, it is reflected upon the cribriform  plate of the
ethmoid  bone, and blocks up all  its foramina.  At this  point,
the olfactory nerves seem to terminate on its surface and  ad-
here very closely  to it.
  From the cribriform plate, the Schneiderian membrane passes
to the cellular part of the ethmoid, and covers smoothly its an-
terior  half.   But behind, as it passes over  the upper spongy
bone, a pendulous  duplicature is formed along its inferior mar-
gin, and is continued beyond the  bone, backwards as far as the
spheno-palatine foramen.  It then lines the  upper meatus and
the posterior cells  of the ethmoid, and  is extended upon the
convex surface of the  middle spongy  bone.  At the inferior
margin of the latter, it forms another loose and somewhat pen-
dulous duplication, which does not go beyond the posterior ex-
tremity of the bone.  The membrane is then reflected into the
middle meatus of  the nose, and  penetrates  into the maxillary
sinus which it lines completely.   The orifice through which it
enters, is about the size  of a crow-quill; is variable in its situa-
tion, being sometimes in the middle of the  meatus, sometimes
more forward, and on other occasions higher up and concealed
by irregularities, in the conformation of the ethmoid.  This ori-
fice, which was found  to be so  large and jagged in the pre-
pared  bone, is reduced  to its present  size entirely by the mode
of  reflection  of the  mucous membrane over its  margins.  In
front of the  latter orifice, beneath the anterior margin  of  the
middle turbinated  bone, the mucous membrane is reflected into
the anterior  ethmoidal  cells by  one or more foramina, and
through the most  anterior of these cells into the frontal sinus.
   From the middle meatus, this  membrane  passes upon  the
lower turbinated bone so as to cover it, and also to form a loose
duplication along  its inferior margin; it then  lines the inferior
meatus of the nose, and is continued on its floor into the part
from which  its description commenced. Under the anterior 
392
NERVOUS SYSTEM.
  part of the  inferior spongy bone, this membrane is  continued
  into the lining membrane of the lachrymal sac, and there forms
  a fold, frequently resembling a valve.  Along the posterior mar-
  gin of the vomer, the membrane of the nostril is continued into
  the corresponding one of the other side, whose arrangement is
  in all respects the  same.
     The pituitary membrane, in its  structure and appearance, re-
  sembles other mucous membranes;  its colour, however, is na-
  turally of a  deeper red.  It consists of two laminas, which  can-
  not be readily separated: the one next to the cavity of the nos-
  tril has the mucous structure; the exterior one  is fibrous, and
  resembles the  periosteum of other parts of  the body.   This
  composition is best seen on the part belonging to the septum
  narium.
     By floating the pituitary membrane in water its mucous la-
  mina is  made  to  exhibit, very  satisfactorily, the villous and
  spongy appearance.  This is particularly evident on the turbi-
  nated  bones.   Its  whole surface  is  studded with  pits or  folli-
  cles of various sizes, irregularly arranged and resembling pricks
  made into a plastic substance with  the point of a  pin.  From
  these cavities or cryptaj  proceeds the mucus of the nose. In the
  thickness of the pituitary membrane, there exist numerous and
  thickly set glands, of a size  so small that they escape common
  observation, but their existence is generally admitted, both on
  the authority of anatomists who have described them,* and on
  the principle of their being always the concomitants of mucous
  membranes.t
     It is owing to the great abundance of blood vessels  in this
  membrane,  to their very superficial course, and to the habitual
  residence of blood in them, that it always presents a deep red
  colour  in the living  state.   These  blood vessels bleed  very
  freely from slight mechanical causes, and are also disposed to
  congestions, which are relieved by the blood  being poured out
  through their exhalent orifices, without laceration  or any  solu-
   tion of continuity.
     Though the description just given corresponds with the tex-
   ture, generally, of the pituitary membrane, yet there are modi-
.  fications of the latter at particular points which it does not fully
* Ruyschii, Epist. Anat. Probl. vii.  Mayer.     t Bichat, Anat. Dei 
ORGAN OF SMELLING.
393
 suit.   For example, at the anterior orifice of the nostril  it is
 insensibly changed into a thin skin, furnished in the male adult
 with stiff hairs (Vibrissce;) and in all the sinuses it is more thin
 and white than elsewhere, being also smooth and shining, and
 not presenting clearly the little pits which  are so distinct in the
 nose.   The surface which adheres to the  sides of the sinuses,
 is destitute of a fibrous structure, and resembles condensed but
 very thin cellular membrane, and is so loosely attached  that
 it peels off with a very inconsiderable force.  When the mem-
 brane of the sinuses is inflamed, it then thickens, admits more
 red blood, and is thus brought to resemble the pituitary else-
 where.
   It is extremely difficult to assign a proper use to  the sinuses
 bordering on and entering into the nose; for, according to Des-
 sault, the sensation  of smell  does not  exist in them.   Bichat
.believed that they, by being filled with  air charged with odor-
 ous particles, were reservoirs of the latter, serving to prolong
 the sensation of smell, which would have been too fugitive if it
 had depended  only on the passage of air during respiration.
 Another problem in regard to these cavities, is the manner in
 which they discharge  the mucus which they secrete. Perfect-
 ly rigid and unyielding, and so situated that the  most frequent
 attitudes  of the head would  rather serve to retain, than to dis-
 charge the contents of most of them  by gravitation, we yet
 seldom see more than their surface smeared with mucus,  and
 accumulations  of it are quite uncommon, except in the diseased
 state.  The secretion  in  them, it is to be observed, is  much
 less abundant  than it is in the nose.
         Of the Nerves of the Pituitary Membrane*

   The pituitary membrane  is furnished with nerves from two
sources; from the olfactory, and from the fifth pair.
   The Olfactory Nerve having formed its bulb, which reposes
in the ethmoidal fossa, sends off from the under surface of the
bulb, the succession  of filaments which penetrate to the nose
through the cribriform plate  of the ethmoidal bone.  The lat-
* Antonii Scarpa, Anatom. Annotaticnes, Lib. ii. 
394
NERVOUS SYSTEM.
 ter, when examined from the upper surface, has  its foramina
 arranged into two rows, one next to the crista galli, and  the
 other next to the cellular portion  of the ethmoid.  Each row
 consists of about six or eight foramina, and between these rows
 there are other foramina, smaller, and not so  much in  a line
 with each other.  The same  cribriform  foramina, when exa-
 mined from the cavity of the nose, are more  numerous, espe-
 cially those belonging to the first two rows, in consequence of
 the latter branching out below into several canals, which may
 be seen very distinctly on the side of the base of  the nasal la-
 mella, and on that of the cellular portion of the ethmoid.
  The distribution of the olfactory nerve corresponds with this
 arrangement of  the cribriform plate, for  it has three rows of
 branches proceeding from the under surface  of its bulb, each
 branch going through its appropriate foramen, and subdividing
 in it, but sometimes two filaments pass through the same fora-
 men.   In a short space after their origin, they become invested
 by sheaths of the dura mater, which are extended a considera-
 ble  distance, and which, by a close  adhesion  to  the nerves,
 make them appear  much  larger below than  they are  at  the
 roots.   When the  nerves  reach  the cavity of the  nose they
 anastomose together, and  descending between  the  bone and
 the  pituitary membrane, they ramify into an infinitude of small
 branches, the terminating filaments of which reach  the  nasal
 surface of the membrane.
  The Internal Branches, or those next to the  crista galli, di-
 verge from the cribriform plate, and pass downward between
 the septum and the pituitary membrane: where they first appear
 in the nose, there are  some few adhesions or anastomoses  be-
 tween them;  but their filaments afterwards keep- perfectly dis-
 tinct, and, spreading themselves out on the pituitary membrane
 of the septum, make an appearance resembling a flat camel's-
 hair pencil.  The  middle  ones are the longest, and may be
 traced almost to  the floor of the nose; the anterior are shorter
 somewhat; the posterior do not reach obviously below the mid-
 dle  of the septum.
  The External Branches have a very different mode of distri-
bution.   While still in their canals they divide  into many fila-
ments, which anastomose frequently with each other, and when
they have fairly got into the cavity of the nose, the same fre- 
ORGAN OF SMELLING.
395
quency of anastomosis continues, so that they form a net-work
of numerous and small meshes, which prevails from the cribri-
form plate to the inferior margin of the middle turbinated bone.
Their filaments cannot be traced below the latter line, and,
therefore, do not descend so low as the filametV.s of the inter-
nal row, neither are they so close to each other.   They do not
penetrate to the ethmoidal cells.   The posterior ones are very
abundant, on the upper turbinated bone, and incline backwards
in their  descent; the anterior are also abundant on the fiat an-
terior half of the ethmoid, and when  they get below the line of
the upper meatus, they  extend backwards to the posterior end
of the middle turbinated bone, and to its inferior  margin.  On
this bone they are less abundant than above it; their meshes are
larger, and their  distribution  is  confined to the Schneiderian
membrane covering its  convex surface.
   The filaments of the  middle row associate themselves indis-
criminately with those of  the external and of the internal row,
according to local convenience.

   The other nerves of the Pituitary  Membrane come from the
first, and from  the second branch of the Trigeminus.  The first
branch of the latter gives off from its nasal branch the nerve
called Internal Nasal, which penetrates from the orbit into the
cavity of th«  cranium, through  the  anterior internal  orbitary
foramen, and lies  covered by the dura mater, at the side of the
crista galli; thence it passes into the cavity of the nose through
the most anterior  foramen of the cribriform plate.

   This Internal Nasal Nerve (Nasalis Internus) having got into
the nose, divides into two fasciculi, an internal and an external.
The internal descends along the anterior margin of the septum,
between the mucous membrane and the bone, and, after a short
course, is divided into two filaments, one of  which, applying it-
self to the posterior face  of the os nasi, terminates by smaller
filaments in the integuments of the lower part of the nose; the
other filament  continues along the margin of the septum to its
lower part, where it terminates by smaller filaments.  The ex-
ternal fasciculus of the Nasalis Internus gives  off early a fila-
ment, which descends along a groove on the posterior face of 
396
NERVOUS SYSTEM.
 the nasal bone, and winding over the lower edge of the latter,
 or passing through a foramen in it, is lost upon the integuments
 of the corresponding part of the nose.  Other filaments from
 the external fasciculus descend upon the  mucous membrane,
 along the external anterior part of the nose, or that which cor-
 responds with the nasal process of the upper maxilla, and ter-
 minate near the anterior extremity of the inferior spongy bone:
 they are three or four in number.  The internal nasal nerve is
 also said to send one or more filaments to  the frontal sinus,
 but they are so fine that doubts  of their existence  are enter-
 tained by Bichat, though they are admitted by J. F.  Meckel.
   The Spheno-Palatine Ganglion, a  part of the second branch
 of the Trigeminus, detaches to the  nose, through the  spheno-
 palatine foramen, several filaments.  One of  these, discovered
 by  Cotunnius, and  admirably  delineated  by Scarpa  and by
 John Hunter, called the Naso-Palatinus, runs across the front
 of the sphenoidal sinus to the upper posterior part of the septum
 narium,  beneath the mucous membrane.  It then descends ob-
 liquely along the septum to  the foramen incisivum, and passes
 through  it to the roof of the mouth.  In many cases,  however,
 a  distinct foramen is formed in the middle palate suture for it,
 anterior  to the foramen incisivum.  The nerve of the left side
 is  anterior to that on the right.   When the  two reach the roof
 of the  mouth, or are near it, they unite to form a little swelling
 called the  naso-palatine ganglion,*  from which several fila-
 ments  arise, and are  spent  upon the  membranous  caruncle
 at this point, and upon the  contiguous part of the palatine
 membrane.
   The spheno-palatine ganglion sends several  filaments to the
 mucous membrane of the upper spongy bone and of the upper
 meatus, and to that of the posterior end of the middle spongy
 bone.  The  palatine nerve, one of its largest branches, in de-
scending  along the posterior palatine canal to the soft  palate
of  the mouth, also contributes to the  supply of nerves to the nose.
Shortly after it  has  arisen from the  ganglion, it sends one or
more filaments to the middle spongy bone, and to the superior
part of the  lower spongy bone, and when it has got, in  its  de-
* J. Cloquet, An^t. 
ORGAN OF SMELLING.
397
scent, on a level with the posterior end of the latter, it detaches
another filament, which supplies  the  mucous  membrane, along
the inferior margin of this bone.
  An opinion advanced by Mery about the close of the seven-
teenth century, has  lately  been  revived by  M. Magendie,  of
Paris, that the olfactory nerves are not those which communi-
cate the impressions of odorous bodies.  In contradiction, how-
ever, to his experiments, it should be stated, that several  re-
spectable anatomists have seen cases where the privation of the
sense of smell during life, was found,  upon examination after
death, to be attended with the absence of the olfactory nerves.


                Of the Blood  Vessels of the Nose.

  The extreme vascularity of the Schneiderian Membrane  is
derived from several sources.   The Internal  Maxillary  Artery
sends through the Spheno-Palatine  Foramen a  large  branch,
which is distributed upon the septum and upon the spongy bones.
The palatine artery also supplies  this membrane with  one  or
more small branches.  The Ophthalmic also  sends the anterior
and the posterior ethmoidal branches to it, from the orbit of the
eye.  The Infra-orbitar artery likewise contributes to its vascu-
larity by one or more branches, sent off in its course  through
the infra-orbitar canal.
  The veins follow the course and distribution of the arteries.
Some  of them, however, unite with  the trunks called  emissa-
ries of Santorini, which come from the sinuses of the dura ma-
ter through the  foramen ovale and rotundum of the sphenoid
bone.
                    CHAPTER II.

           OF THE EYE, AND ITS DEPENDENCIES.

  The organ of vision  which depends upon the optic nerve for
its usefulness, is formed by the  Ball of the Eye and many De-
  Vol. II.—35 
398
NERVOUS SYSTEM.
pendencies or Auxiliary parts, all of which are situated within
the orbit, and fill up its cavity.


        SECT. I.--OF THE AUXILIARY PARTS OF THE EYE.

  The Eyelids  (Palpebrae) are placed at the anterior orifice of
the orbit, and serve to shut out the light from the eye, by their
closing; and also, by their frequent motions, to sweep the front
of the eyeball, so as to remove, from its transparent part, moats
and dust.   They are distinguished into  upper and lower, and
the place at each end, where the horizontal fissure between them
ceases,  is  called their Commissure, Angle or Canthus.  The
angle next  to the nose, or the internal, is called the Great one,
and the other, the Little one.
  The Internal Canthus is united to the nasal process of the su-
perior maxillary bone by a rounded tendon, (Ligamentum Pal-
pebrale Internum,) the origin of the orbicularis palpebrarum mus-
cle, and which passes horizontally inwards, being nearly half
an inch in length.  It throws  the skin into a small ridge, which
may be distinctly seen and felt  at this point.   The External
Canthus is  held in  place by its general attachments of  cellular
substance and by the external palpebral ligament.
  The upper eyelid is somewhat larger than the lowrer, but the
structure of both is the same, for  each one is  formed by  skin ex-
ternally ; next to it a plane of muscular fibres, being the orbi-
cularis  palpebrarum; then a plate of cartilage; and, lastly, a
thin membrane uniting it to the eyeball.
  There is nothing in the texture of the skin of the eyelid which
needs description  in a  manner  more particular than that of
stating its fineness, its thinness, the looseness of its attachment
to the muscle beneath by long yielding cellular substance, and
the deficiency of adipose matter.  It is rendered prominent at
the superior margin of the orbit, both by the projection of the
bone  there, and by  the presence of the corrugator supercilii
muscle at its internal extremity.   This prominence is furnished
with an arched cluster of hairs, (Supercilia,) which have their
loose ends inclined horizontally outwards, and are rather more
abundant at the root of the nose than externally.  The super-
cilia of the two sides are separated commonly by a small bare 
THE EYE.
399
space called Glabella, the existence of which adds much to the
calm and intellectual expression of the human  countenance;
whereas, the junction of the two eyebrows, by the hairs filling
up this space, gives a gloomy, and, occasionally, a ferocious
appearance.
   The margins  of the eyelids are  also furnished with hairs,
(Cilia,) the roots of which are insinuated between the skin and
the tarsi cartilages: the most deeply seated%seem, indeed, to pe-
netrate the  latter.  The hairs of the upper lid are longer and
more numerous  than those of the lower: they are concave up-
wards, while the latter are concave downwards, so that the con-
vexities of the  two ranges of hairs come in contact when the
eyelids are closed.  The hairs of each cilium are disposed into
three or four rows, by which a long brush is formed, the  central
hairs of which are longer and larger than any others.
   The hairs of the supercilia and of the cilia resemble one ano-
ther strongly, for, when examined  closely, each one will be
found to have a  bulbous soft root, just beyond which there is a
narrow part.  The middle of the hair is swollen, and  its  ex-
ternal extremity is brought  to a  fine point.  These hairs cor-
respond in colour with the hairs  of the head.

   When the orbicularis muscle is removed, a  ligamentous or
fibrous membrane is found passing from the external  margin of
the orbit to the corresponding margin of the palpebral cartilages,
and separating the eyelids from the parts contained within the
orbit.  There is a partial decussation of the fibres of this mem-
brane, from the external commissure of the cartilages to the ex-
ternal edge of the orbit; it has more firmness than any other
part of the membrane, and is the external palpebral ligament;
(Ligamentum Palpebrale Externum.)  On the side of the internal
canthus of the orbit there is  no corresponding ligamentous  ex-
pansion, but a few irregular fibres, which allow the masses of
fat beneath to project forwards between their fasciculi.

   The Palpebral Cartilages (Tarsi) are two in number,  one at
the margin of each eyelid, to which they communicate a smooth,
even  surface, from the internal  to  the  external commissure.
They are between the orbicularis muscle and the tunica conjunc-
tiva.  The upper one is larger than the lower, resembles an oval 
400
NERVOUS SYSTEM.
cut in half in its long diameter, and is about six lines broad in
its middle: the lower one is of a breadth, nearly uniform, of
about two lines.  Their internal extremities cease just before
they reach the puncta lachrymalia, and are attached to the in-
ternal palpebral ligament, which has been described as one of
the origins of the orbicularis oculi  muscle, at the nasal  process
of the upper maxillary  bone;  their external extremities cease
just before their commissure, and are firmly attached to  the
external palpebral ligament.
  These cartilages  are thicker where they form the margin of
the eyelids, and  have there a slope or bevel, by which, when in
contact, a small groove is formed on their posterior  surface.
From their resistance to the coneentric contractions of the or-
bicularis,  they keep the eyelid smooth, and favour its sliding
upon the eyeball.  Certain animals, being destitute of these car-
tilages, when they wink, the skin, by the contraction of the or-
bicularis,  is drawn up like the mouth of a purse.

  Conjunctiva.—Below the palpebral cartilage is the fourth layer
of the eyelid, the conjunctiva.   It is a white, thin, and diapha-
nous membrane, in the uninflamed slate.  Beginning at the roots
of the cilia, where it is  continuous with the skin, it covers the
posterior  face of each eyelid, is reflected for  eight or ten lines
towards the bottom of the orbit, and then passes to the  eyeball,
of which  it covers the anterior half, not excepting the cornea.
It penetrates into the lachrymal passages, to be continuous with
the lining  membrane of the lachrymal sac.
  From this description,it is evident that the tunica conjunctiva
has one surface presented against itself when the eyelids are
closed ; this surface is lubricated and very smooth, so as to per-
mit a free motion of the lids and ball of the  eye.  The other
surface is connected in its anterior half by cellular substance to
the eyelids, and  in its remaining part to the ball of the eye, by
the same  means.  It is  united rather loosely to  the sclerotica
till it gets near the margin of the cornea; but to the latter it ad-
heres so firmly,  and changes there so much its texture, that it
seems like a portion of the cornea.
  This membrane, from  its continuity with  the  skin  and  the
lining membrane of the nose,  from its sympathies with them,
from the nature  of the discharge from it, and from its extreme 
THE EYE.
401
 sensibility, is ranked by Bichat among the mucous membranes.
 It has, however, some peculiarities in its structure, for it is en-
 tirely deficient in villosities, and though most abundantly fur-
 nished with capillary vessels, they do not obviously admit red
 blood, but in a state of irritation.

   Glandular Palpebrarum.—These bodies also called the glands
 of Meibomius, from an anatomist who has described them par-
 ticularly, are situated at the margin of each eyelid, between its
 cartilage and the conjunctiva.  They are about two or three
 lines long, and appear like small, white, serpentine threads, run-
 ning at right angles to the margin of the lid, near to, and paral-
 lel with one another.  They are more abundant on the upper
 than on the lower lid.  They terminate by  a  row of small ori-
 fices in the margin of the lid, just behind the cilia.  For prevent-
 ing the overflowing of the tears, and the sticking together of the
 eyelids, they  discharge an unctuous fluid,-which may be made
 manifest by squeezing them.  Their secretion is occasionally
 much augmented, and then has a large quantity of serum  and
 glutinous matter in  it: in this case the evaporation  of the se-
 rum makes it adhesive, and  causes the eyelids to adhere after
 they have  been closed for some time, as in sleep.


                          Muscles.

   The Musculus Levator Palpebral Superioris is placed in the
 superior part  of the orbit.   It arises  by a small round tendon
 from the  upper margin of the optic  foramen, and,  becoming
 fleshy, it expands itself into a long  thin triangle, of which the
 base is in front.  It covers the rectus superior muscle.
   Terminating in front by a thin tendinous expansion, it is in-
 serted into the superior margin of the upper palpebral cartilage;
 but some of its fibres continue on between the latter and the  or-
 bicularis to the lower edge of the cartilage.
   It raises the upper lid, by drawing  it towards the bottom of
 the orbit.

  There are six muscles concerned in moving the eyeball, four
of which, from their direction, are said to be straight; and the.
                            35* 
402
NERVOUS SYSTEM.
other two, for the same reason, are called oblique.  With the
exception of the inferior oblique, they all arise from the bottom
of the orbit..

  1. The Rectus Oculi Superior, being placed immediately be-
low the levator palpebrse, arises from the superior margin of
the  optic foramen.   It runs forward, increasing somewhat in
breadth, and  is inserted by a broad  thin tendon into the scle^
rotica, two lines from the cornea.
  It turns the eye upwards.

  2. The Rectus Oculi Externus arises from the external mar-
gin  of the optic foramen.  It then advances along the middle of
the  external wall of the orbit, near the periosteum, to which it
adheres slightly, and is finally, inserted, by a thin broad tendon,
into the external side of the sclerotica, about two or three lines
from the cornea.
  It abducts the eye, or turns it outwards..

  3. The Rectus Oculi Inferior arises also from the optic fora-
men, at its inferior margin, and, lying upon the floor of the or-
bit as it  advances forwards; it is inserted, tendinous, into the
under surface of the sclerotica, two lines from the cornea.
  It depresses the eye, or turns it downwards.

  4. The Rectus Oculi Internus arises from the internal mar-
gin  of the optic foramen, and goes forwards along the internal
wall of the orbit, being separated from it by a layer of adipose
matter.  It is inserted, by a tendinous expansion, into the inner
side of the sclerotica, two or three lines from  the cornea.
  It a'dducts the eye,.or turns it inwards.

  5. The Obliquus Oculi Superior is placed along  the upper in-
ternal angle of the  orbit.   It  arises from  the corresponding
margin of  the optic foramen, by a small round tendon;  it then
advances forwards, and when it has got near the margin of the
orbit, it is  converted into a long round tendon.
  The  tendon passes through a  cartilaginous loop which is
formed for it, just at the inner margin of the supra orbitary fo-
ramen,, and is connected to the loop by longjoose cellular sub-. 
THE EYE.
403
stance, which permits it to play freely backwards and forwards.
The tendon from this point changes its direction by going back-
wards and outwards: it also becomes more flat, and is then in-
serted into the upper face of the sclerotica near its middle, just
beneath the internal  margin of the rectus superior muscle.
  This muscle is the longest, but the most delicate of those be-
longing to the eyeball.  According to Soemmering, it draws the
eyeball forwards, and towards the internal canthus, and directs
the pupil towards the cheek.   By the aid of the inferior oblique*
it draws the  eyeball towards  the nose: it expresses pride: it
appears to be greatly excited  in anger.*

   The preceding muscles are all connected, either directly or
indirectly, with  the theca of the optic nerve.

   6.  The Obliquus Oculi Inferior is at the bottom of  the orbit.
   It arises, by a small tendinous beginning,  from the  os maxil-
lare superius at the side of the  os  unguis, and, increasing in
size, it goes below the rectus inferior outwards and  backwards,
and gets between the eyeball and the rectus externus.  It is
then inserted into the outer face of the  sclerotica, about half
way between the optic  nerve  and the cornea.
   It causes the eye to revolve on its axis, and turns the cornea
towards the  nose.   Its  action, however, is  much modified  by
that of the other muscles.  As  one axis  of  the  eye  is  a line
passing from the centre of the  optic nerve, forwards and out-
wards, it will be found that each of the oblique  muscles is  in-
serted, at right angles, to this line;  consequently, their simple
and unmodified  action is to produce a  revolution of the eye, on
its axis, in the line  of their insertion,  the first making the eye
roll inwards, and the latter outwards,  on  the  two poles:  they,
therefore, are strictly antagonists.

                 Of the Lachrymal Apparatus*

   The apparatus for the tears (Organa Lachrymalia, vise La-
chrymales) consists  in  the Lachrymal Gland, the Lachrymal
Ducts, the Lachrymal Sac, and a few other parts.
  * Bulbum in  priora et  angulum internnm versus movet; pupillam deorsum ad
genani dirigit; juvante musculo obliquuo inferiore bulbum nasum versus trahU;
animi. fastum exprimit;  ira valde commoveri videtur. 
404
NERVOUS SYSTEM.
   The Lachrymal Gland (Glandula Lachrymalis) is situated
in the orbit, immediately below and within  the  external angu-
lar process of the os frontis.  It secretes the moisture that lu-
bricates the eyelids and eyeball, and which, when it becomes
abundant, is called the Tears.  It is a flattened oblong or oval,
convex above and concave below, of ten lines in length, six in
width, and about  two lines at its thickest part, for its edges are
somewhat bevelled.   It may be considered  as divided into two
parts or lobes, of which the superior is the larger and occupies
the depression attributed to it in the frontal bone, while the in-
ferior, being the smaller, is placed at the anterior margin of the
depression.*   It is lined below by the conjunctiva, and is pro-
tected in front by the margin of the orbit which it touches.
   This gland resembles much a salivary gland in its light pink
colour, and in its  consisting in a congeries of lobules united by
cellular  substance.  Unless we are to consider the latter  as
such, it has no regular capsule.   From  the  lachrymal gland
there proceed six or seven excretory canals, extremely fine,
and found with so much difficulty that many distinguished ana-
tomists have sought for them in vain.t  The orifices  of  these
ducts have been  laid  down by Soemmering, as  equi-distant;
forming in the conjunctiva, a row half  an  inch long, and pa-
rallel with the superior  margin of the  upper tarsus cartilage,
beginning a quarter of an inch above its external end and going
inwards.   By squeezing the gland, small drops  like tears, will
appear on the nearest surface of  the conjunctiva, but not  in
the regular order laid down by anatomists  for  the lachrymal
orifices.
  The Lachrymal Ducts (Canaliculi Lackrymales) are situated
immediately beneath the skin, at the  internal commissure of the
eyelids,  in their posterior margin, and  behind the orbicularis
muscle.   There is one for each  eyelid.   They  are about half

  * These lobes are frequently marked off by a ligamentous band passing from
between them to the external angular process.
  t These  are Morgagni, Haller, Zinnv and Durvemey,  Meckel, Soemmering,
and many others, speak with all confidence concerning them.  Bichat admits
that he only acknowledges their existence inductively. Dr. Monro, of Edinburgh,
claims to have discovered them by plunging the eye into a coloured fluid which
was absorbed by them.  Dr. W. Hunter seems to have  a prior claim to Dr.
Monro.  See Med. Comment, p. 54.  Mascagni also acknowledges their exist-
ence:—Prodromo della Grande Anatomia, voki. p. 60.. 
THE EYE.
405
 an inch long, though the lower one  is rather longer than the
 upper.
   The  lachrymal ducts commence at a small elevation of the
 margin of each eyelid, bordering immediately upon the internal
 end of  the tarsus cartilage, but perfectly distinct from it.   This
 elevation is conical, has a vermicular  motion during life, and
 points towards the ball  of the eye; in its centre is a very small
 foramen, called  the Punctum Lachrymale, which is the begin-
 ning of the lachrymal duct.   The punctum  is about a line in
 length; and enlarging in its course, it  runs at right angles to the
 duct into which it empties, of which it may be called the Orbital
 Orifice: the upper one will, therefore,  ascend, and the lower one
 descend.
   The  lachrymal ducts are much larger  than the puncta, and
 are in their whole course about one line in diameter.  At their
 orbital extremities, they go rather beyond the puncta, so as to
 form a  small  cul-de-sac.   These canals converge, and having
 got to the internal angle of the eyelid, they are there placed be-
 hind the internal palpebral ligament.  They then discharge, by
 distinct orifices, but very near each other, into the lachrymal
 sac at its external anterior  part, where they form a small round
 projection  into the interior of its cavity, and  are  overlapped,
 sometimes,  by  a small duplicature  of its lining membrane.
 When the eyelids are closed, the lachrymal ducts are horizontal
 and  nearly parallel, but when the eye is open the upper duct is
 elevated, and thereby becomes oblique;  it is hence more proper
 for the introduction of instruments into  the lachrymal sac.

   The Lachrymal Caruncle (Caruncula Lachrymalis) is placed
 in the angle formed by the internal junction of the eyelids.   It
 is a red-coloured tubercle, differing in  size in  different individu-
 als, but  commonly as large as a grain  of wheat  It is conical,
 and obtains its redness from the conjunctiva being reflected over
 it: when accurately examined, it will be found to consist in a
 group of sebaceous glands; of which, according to  some anato-
 mists, there are seven ranged two in a row, and one on the top
 of the others.   The surface of this body is beset with very fine
hairs, and the orifices in it are distinguishable with a glass.

   The Semilunar Valve, or Fold, (Plica  Semilunaris,) is situ- 
406                   NERVOUS SYSTEM.
ated immediately at the outer  margin of the caruncle.   It ha3
the form of a triangle, the point of which runs into the caruncle,
and the base, which is somewhat crescentic, is directed towards
the eye.  It is a duplicature of the conjunctiva, becomes very
manifest from behind, and, in some persons, has its base fur-
nished with a very small strip of cartilage.*   I have seen seve-
ral cases  of the kind very well  marked; they occur  more
frequently in the African, according to my personal experience.
Between the base and the caruncle it is formed into a  number of
loose wrinkles, which disappear when the eye is very much ab-
ducted.
   This body, in  the human subject, is evidently intended to per-
mit to the eye a  great freedom of abduction.  Its analogy, how-
ever, with the third  eyelid of animals is very striking, and the
difference is rather in the full development of the latter, than in
the organization.  It is very properly remarked by J. F. Meckel,
that in descending the scale of animals, the third eyelid is al-
ways in an inverse ratio to the other two, till it  ends by being
a complete substitute for them,
   Surrounding the Lachrymal caruncle may be observed a de-
pression on  the  adjoining part of the plica semilunaris.  Into
this depression the puncta lachrymalia are directed, and there
play up and down: the tears accumulate in it; from which cause
the depression is called Lacus Lachrymalis.

   The Lachrymal Sac (Saccus Lachrymalis) is placed at the in-
ternal canthus of the orbit; in the depression of the os unguis,
and of the nasal process of the upper maxillary bone.   It is an
oblong cylindroid cavity, and extends from the transverse facial
suture to the anterior extremity of the  inferior  meatus of the
nose; being concealed there by the anterior part of the inferior
turbinated bone.  It  is crossed at its front part by the tendon  of
the orbicularis, which, with a few fibres of this  muscle, adheres
to it.
   The  course of the lachrymal sac is, at first, slightly forwards
in the descent to the nose; but, when it reaches the lower part
of the orbit, it is afterwards slightly backwards: so that it may
be considered as forming an obtuse angle forwards.  It also de-
*'Meckel. 
THE EYE.
407
creases  somewhat in size from above downwards, and at its
lower orifice is flattened from side to side.
  The lachrymal sac consists in two membranes; an exterior
fibrous one continuous with the  periosteum  of the contiguous
bones, and an interior mucous one, which is thick, villous, of a
red colour, from the abundance of its blood vessels, and abound-
ing in mucous follicles.   The interior is continuous above with
the lachrymal ducts, and below with the Schneiderian mem-
brane.  On a line with the floor of the orbit, this internal mem-
brane is thrown into a circular duplicature, considered by some
anatomists as forming the proper boundary of the  lachrymal
sac:  all below this is called by them Nasal Canal.   The dis-
tinction is rather arbitrary, and, in some degree, hurtful to clear-
ness of description: a much better plan is to call the part above
the valve  the orbital portion of  the sac, and the part  below the
valve its  nasal  portion.   Sometimes  there is a second valve
about three lines below the first, and  generally another at the
nasal orifice, formed by a duplication of the Schneiderian mem-
brane.
   The Tensor Tarsi is a small muscle on the orbital face of the
lachrymal sac, of which I gave a detailed account some years
ago.*  It arises from the posterior superior part of the  os unguis,
just in advance of the vertical suture between the os planum and
the os unguis.   Having  advanced three lines, it bifurcates; one
bifurcation is inserted along the upper lachrymal duct, and ter-
minates at its punctum, or near it; and the lower bifurcation has
the same relation to the lower lachrymal duct.  The  base of the
caruncula lachrymalis is  placed in the angle of the bifurcation.
The  superior and the inferior  margins of  the muscle touch the
corresponding fibres of the  orbicularis palpebrarum, where the
latter is connected with the margin of the internal canthus of the
orbit, but may be readily distinguished  by  their   horizontal
course.  The nasal face of  this muscle adheres very closely to
that portion  of the sac which it covers, and also to the lachry-
mal ducts.  The lachrymal sac rises about  a line above its supe-
rior  margin, and extends in the orbit four lines below its  infe-
rior margin.  The  orbital face of the muscle is covered  by a

         * Philadelphia Journal of Med. and Phys. Sciences, 1824. 
408
NERVOUS SYSTEM.
 lamina of cellular membrane, and between this  lamina and the
 ball of the eye are placed the valvula semilunaris, and a consi-
 derable quantity of adipose matter.
   As the bifurcated extremities of the muscle follow the course
 of the ducts, they are covered by the tunica conjunctiva.  When
 this muscle is examined from behind, the eyelids being in  situ,
 it becomes obvious that it is concave on its orbital surface, and,
 consequently, convex on the nasal; that the muscle is an oblong
 body,  half an inch in length, and about three lines wide, bifur-
 cated at one end:  and that it arises much deeper from the orbit
 than any acknowledged origin of the orbicularis.  The superior
 fork, however, has a few of its fibres blended with the orbicu-
 laris.
   In regard to the use of this muscle: its attachment to the pos-
 terior fece of the  sac is such, that it draws  the  orbital parts of
 the sac away from the nasal, and dilates the sac, from  the nasal
 face of the latter being  fixed to the bones.   As this  muscle is
 cylindrically concave on its orbital side, it is evident that when
 it contracts, the fibres become straight, or  nearly so, like  the
 fibres of the diaphragm, and the  cavity of the sac is  enlarged
 after the same manner as the cavity of the thorax.  A tendency
 to a vacuum being thus produced by it, the  valves or folds of
 the internal membrane of the sac  permit the vacuum to be filled
 more readily through the puncta than from  the nose; and the
 puncta being continually bathed in the tears of the lacus lachry-
 malis, both in the waking and in the sleeping state, the tears are
 constantly  propelled  through them  by  atmospheric  pressure.
 The evacuation of the sac is no doubt accomplished by its own
 elasticity, and  by the contraction of  the  orbicularis;  probably
 in a chief degree  by the  latter, because in  persons who have
 epiphora, or a tendency to obstruction in the  nasal duct, the ac-
 cumulation of tears and  matter principally^ takes place at night,
 when the action of the orbicularis  is suspended  by sleep.  For
 these reasons, we should argue that this little muscle is active at
all times, both night and day.  To Dr. Physick I am  indebted
 for suggesting another use for it; to wit, that of keeping the lids
 in contact with the ball of the eye.
  Somepersonspossess unusual voluntary powerover this muscle,
of which I have seen several examples.   In each  instance the in- 
                            THE EYE.                        409

dividual could shorten so much the internal angle of the eyelids,
as to conceal it, along with the puncta, in the internal canthus
of the orbit.*

                  Of the Nerves of the Orbit.

   In addition to the optic nerve, there are several belonging to
the eye and to  its auxiliary parts;  they are derived  from  the
Motor Oculi or third pair; from the Trochlearis, or fourth pair;
from the first branch of the Trigeminus, or fifth pair; and from
the Motor Oculi Externus or  sixth pair.   For an account of
which, see Nerves.


                  Of the Arteries of the Orbit.

   The Eyeball, and its  auxiliary parts, are principally supplied
by the Ophthalmic Artery, which, as was mentioned  in the ac-
count of the Brain, is a considerable  branch given  off by the
Internal Carotid at the fore part of the Sella Turcica.   This
branch gets into the orbit on the outer side of the optic nerve
through the optic  foramen, and, after a  short  course, crosses
obliquely above  the optic nerve, so as  to pass  to  the internal
side of the orbit.  It sends off a great many small trunks, which
are very inconstant both  in their size  and origin;  they are as
follows:—

   1. Arteria Lachrymalis arises, commonly, soon after the oph-
thalmic has got into the  orbit: it goes forwards between the rec-
tus  superior and the  rectus externus muscle, to which  it dis-
tributes arterioles;  it then reaches the lachrymal gland, and

  • Having laboured, first of  all, to convince the profession of the existence of
this muscle, the next step, as is usual on such occasions, was to vindicate my own
pretensions to its discovery, and to attempt to remove such objections as re-
quired attention.  For the arguments on this subject, I refer to the Philadelphia
Journal of Medical  and Physical Sciences, of Nov. 1824, edited  by Professor
Chapman.  My claims  have been unequivocally admitted by Messrs. Breschet
and Jourdan, of Paris, anatomists of unusual distinction, in the translation which
they have made of J. F.  Meckel's Manual of Anatomy, vol. iii. p. 219; by Gery, in
the Melanges de  Chirurgie e"trangere, Geneva, 1824, p. 415; and  by Professor
Giuseppe Trasmondi, in the Arcadica Journal of  Home, &c. vol. xix. p. 1, 1823
   Vol. II.—36 
410
NERVOUS SYSTEM.
having left branches with it, what remains issues out at the ex-
ternal angle of the eye, so as to supply the contiguous part of
the upper eyelid.

  2. Arteriae Ciliares.  According to  Soemmering, before the
origin  of the lachrymal artery, the ophthalmic detaches from
one to  three ciliary, which penetrate into the ball-of the eye
near the optic nerve.  Other arteries  of the  same class arise
subsequently from the ophthalmic, and, occasionally some  of
them from the lachrymal  itself.   They go to  the choroid coat
of the  eyeball and to the iris.

  3. The Arteria Centralis Retinae arises from among the clus-
ter of ciliary arteries, and, like them, has no invariable root.  It
penetrates the optic nerve about  the middle of its orbitar por-
tion, and, going in its centre, gets into the eye  through the crib-
riform part of the sclerotica.  It is then distributed by ramus-
cles to the retina, to the tunica hyaloidea, and to the  capsule of
the lens.

  4. The Arteria Ethmoidea Posterior is inconstant in  exist-
ence, and comes at one time from the  trunk, at another from a
branch of the ophthalmic.  It passes over the superior oblique
muscle, and penetrating through the posterior orbitary foramen,
is spent by arterioles upon the  neighbouring  part of the dura
mater, and upon the posterior ethmoidal cells, where it anasto-
moses  upon the Schneiderian  membrane, with branches from
the internal maxillary.

   5. Arteriae Musculares.  Of these there are  two; one of them,
the inferior, sends branches to  the rectus internus, rectus infe-
rior, and obliquus inferior oculi; also to the lachrymal sac, and
to the parts about the bottom of the orbit.  It occasionally  de-
taches some of  the ciliary arteries.   The superior muscular
branch is also called the Supra Orbitar.  It supplies the mus-
 cles of the superior part of the  orbit, and then issuing through
 the supra orbitary foramen, it is spent  in arterioles, upon the os
 frontis and its periosteum, and  upon the orbicularis oculi, cor-
 rugator supercilii, and occipito-frontalis.  It  anastomoses there
 with other branches of the ophthalmic,  and  with the temporal
 artery. 
THE EYE.
411
  It is usual for the anterior ciliary arteries to come from the
muscular branches.

  The Ophthalmic Artery, after having detached all the afore-
said branches, is much diminished in volume, and,  advancing
along the internal parts of  the orbit, its next branch is—

  6. The Arteria Ethmoidea Anterior, which  dips into the an-
terior  internal orbitary foramen,  and is divided  into small
branches, some of which are spent upon the adjacent portion of
the dura  mater, others upon the frontal sinus and the  anterior
ethmoidal cells.  Some of these branches penetrate from the
cranium throagh the cribriform plate into the nose, and, ramify-
ing upon the Schneiderian membrane, anastomose with the in-
ternal maxillary.

  7. The Arterias  Palpebrales  are two in number:  they come
sometimes from  a common  trunk, and on other occasions  arise
separately.  One is  the Superior, and the other the Inferior.
The latter arises first, and is distributed to the conjunctiva, the
caruncula lachrymalis, lachrymal  sac; and finishes by many
small  branches  to  the lower eyelid, that anastomose with the
infra-orbitar artery, so as to form the lower tarsal arch.  It
also anastomoses with  the lachrymal artery by its extreme
branches.

  The  Superior Palpebral Artery also distributes branches to
the conjunctiva, sac, and caruncle; it then emerges  above the
inner palpebral  ligament,  around  the margin of the superior
eyelid, and forms, along with the lachrymal and the supra orbi-
tar artery,  the  superior tarsal  arch, which  distributes small
branches, in great profusion, to the  orbicularis muscle, and to
the structure,  generally, of the lid.  It anastomoses, externally,
with the lower palpebral artery.

  8. The Arteria Nasalis is sometimes a well marked continua-
tion of the ophthalmic.  It passes  out of  the orbit at its inter-
nal canthus, above the internal  palpebral  ligament, and anasto-
moses at the root of the nose with  the facial artery.   It is dis-
tributed to the side of the  nose, and to the lower part of the
forehead.   Its chief contribution to the eyelids is at the internal 
412
NERVOUS SYSTEM.
end of the orbicularis, where it anastomoses with the palpebral
arteries.

  9. The Arteria Frontalis passes  out of the orbit near the su-
pra orbitary foramen. It is quickly divided into branches, which
go to the orbicularis and corrugator muscles,  to  the  occipito-
frontalis, and to the frontal sinus.


                  Of ihe Veins of the Orbit.

  The blood distributed to the eve-ball and to its auxiliary parts,
has two routes for returning to the heart, one through the ca-
vernous sinus, and the other by the superficial veins of the face.
As a  general  rule, all  the  branches of the ophthalmic artery
which reach the  eyelids, or  become otherwise superficial, re-
turn their blood by the latter route; and those whose distribu-
tion is to the ball  of the eye and to the parts deeply seated in
the orbit, return their blood by the sinus.
   When the veins are well  injected, a very considerable num-
ber is  manifested in both eyelids.  They form a handsome net-
work, the meshes of which  are small and numerous, and com-
mence by small roots at the margin of the eyelids.  The ves-
sels of this net-work becoming, successively, larger from the
centre to the circumference of the orbicularis, cover the whole
surface of the latter, and  from the thinness of the skin are
readily seen  beneath it.  The veins of  the lower eyelid are
discharged into the  facial  vein, where it borders on the orbi-
cularis; and  the veins of the upper lid, being bordered  along
the superior margin of the orbicularis by a horizontal branch
of the temporal vein, discharge themselves into it.

   The Ophthalmic  Vein (Sinus  Ophthalmicus) is  the  large
trunk  within  the  orbit which  receives, successively, the re-
maining  blood of the eye, and passing along the  internal parts
of  the orbit, crosses  over  the  oplie  nerve, and penetrates
through  the  optic  foramen  into the cavity  of  the  cranium,
where it terminates in  the  cavernous sinus.   It may be  con-
sidered as commencing by an anastomosis with  the  facial
vein at the  internal canthus;  it  then  receives  the follqwing
branches:— 
THE BALL OF THE EYE.                  413
  1. The nasal, which arises from the parts about the internal
canthus of the eye.
  2. The anterior ethmoidal, which comes from  the nose and
frontal sinus.
  3. Branches from the recti and obliqui muscles.
  4. The lachrymal vein, from the  lachrymal gland and leva-
tor  palpebrae muscle.
  5. Posterior ethmoidal vein, from the nose.
  6. The ciliary veins, or those of the choroid coat, which are
very numerous.
  7. The central vein  of the retina, which  is collected from
three or four principal branches, and follows the course of the
artery  of the same name, through  the cribriform part of the
sclerotic coat, and through the centre of the optic nerve.  The
trunks  of this  vein  anastomose, at the anteriof-margin of the
retina, with those of the Ciliary Body.

  There are,  of course,  frequent  anastomoses between  the
veins of the eyelids and the primitive branches of the ophthal-
mic vein.

             SECT. II.--OP THE BALL OF THE EYE.

  The Eyeball (Bulbus Oculi)  is situated within  the anterior
half of the orbit, from which  it is kept separated by its auxili-
ary parts, and by a large quantity of adipose matter which fills
up  their interstices.  It  is very nearly  spherical, but  not so
much so as to prevent its antero-posterior diameter, which is
about an inch  long, from exceeding in measurement  every
other.   Such, at least,  is the general opinion of anatomists,
but from experiments, made  by distending  the eye with mer-
cury, I have been  induced to doubt its correctness, and espe-
cially in the African; for,  in the latter, I have uniformly found
the transverse diameter to exceed the antero-posterior by a line
or more.  The Eyeball is also somewhat  flattened at the inser-
tion of each of the straight muscles.
  It is  formed by a series of concentric tunics, one investing
the  other, and by humours contained within those  tunics.   Of
the  former, the Sclerotica and the Cornea  are external, the Cho-
roidea  and the Iris next,  and the Retina is internal.   Of the
                           36* 
414
NERVOUS SYSTEM.
Humours, the Vitreous is, by far, the most abundant, and con-
stitutes a principal part of the eyeball; the Crystalline  Humour
is in front of the vitreous;  and the  Aqueous  is placed  between
the crystalline and the cornea.

              Tunics, or Membranes  of the Eyeball.
  The  Sclerotic Coat (Tunica  Sclerotica,  Albuginea) forms
about five-sixths  of the exterior investment of the eyeball, the
remaining sixth of which  is  obtained from the cornea.  At its
posterior part it is joined by the optic nerve:  this junction does
not occur precisely at  its axis or centre, but at the inner side of
if.   When the optic nerve is detached at this junction, a small
round hole is perceptible in the sclerotica, or, rather, it is more
frequently perceived as a thin  cribriform  lamella, through the
holes of which the pulpy part of the optic nerve passes, so  as
to get within the eye.   This cribriform lamella, or the appear-
ance of it, is no doubt produced  artificially by the nerve being
commonly cut through very near the eye; and, as Mr. Jacobs,
of Dublin, very properly suggests, should be  considered as  the
most anterior termination, or the  point of the  optic nerve, in-
stead of as  a  portion  of the sclerotica.  The neurileme of the
optic nerve, is so arranged, that small round longitudinal canals
are left, which contain the  nervous matter: from this cause it
happens that a thin section of the optic nerve in any part of its
course in the orbit, will, if held up  to the  light, manifest  the
same cribriform arrangement with the part  alluded to.  This
part of  the  structure of the optic nerve will  be  readily under-
stood by the American student, in  comparing it with the pith
of the Indian  corn-stalk, which, being traversed longitudinally,
by many  fibres, upon the drawing of them out, an equal number
of longitudinal canals  is left in  their places.
   At its  fore part, the edge of the sclerotica  is bevelled  all
around  for  its junction  with the  cornea; and  though nearly
circular, is not completely so, from  its horizontal diameter being
somewhat greater than any other.   There are several  orifices
of inconsiderable size scattered  over  the  sclerotica,  some of
which are oblique  and others  direct:  they transmit the blood
vessels  and nerves.  The  Sclerotica is nearly a line  in  thick-
ness at  its back part,  from which it gradually becomes reduced
to half  that thickness  in front, where it is strengthened by the 
THE BALL OF THE EYE.
415
tendinous insertions of the recti muscles.   Its internal surface
is smooth  and somewhat shining, being  loosely attached to
the cellular substance intervening  between it and the choroid
coat; but  the  external surface  is rough, and  more obviously
fibrous, and is attached somewhat strongly to all  the adjoining
parts.
  This membrane is of a white  colour, and consists of a single
layer, whose structure is essentially  fibrous.   The  fibres are
very closely compacted, and compose  an intertexture  which
cannot be unravelled.  It is so closely united  to the dura mater
covering of the  optic nerve, that many anatomists, notwith-
standing its greater thickness,  are  disposed to speak of it as a
continuation of the same.  Its strength and its want of  elasti-
city suit it remarkably to maintain the form of  the eye, and to
resist injuries.  Out of the many blood vessels that penetrate it,
but few  ramify in its structure, and the existence of nerves in
it is by no means evident.
   The tunica arachnoidea follows  the course  of the optic nerve,
within its coat of dura mater, and forms, in the  eye, just around
the cribriform  plate, or foramen of the sclerotica, a circular pad :
it is then  reflected on  the  internal face of  the  sclerotica, as
far as its anterior  edge.   It  is this which causes the internal
face of the sclerotica to be smooth and  shining, and thereby to
correspond with  that of  the  dura  mater.*  This circumstance
is more readily proved in a very young  eye, than in the adult
one.

   The Cornea, as mentioned, fills  up the aperture at  the fore
part of the sclerotica, and, of course, has the same diameters,
with this  opening; measuring thereby more transversely  than
in any other direction.   It is a segment of a smaller sphere than
the sclerotica, and  is, consequently, more  convex than it.  Its
 thickness is uniform, and commonly exceeds  that of the sclero-
tica at the fore part of the latter.
   Its circumference  adheres  very  closely to the sclerotica, and
presents a bevelled or oblique edge, which is inserted into the
corresponding  bevel of the sclerotica, so that  the  latter includes
the former.  The closeness  of  this junction  induced the older

  * J. F. M.eck,el.  Zinn supposed this surface to be derived from the pia ma-
ter-. 
416
NERVOUS SYSTEM.
anatomists to consider these membranes as one  and the same,
notwithstanding their obvious difference of structure and of pro-
perties.  Their adhesion yields t%protracted maceration.  The
cornea is covered in front  by a  continuation of the tunica con-
junctiva, which unites the eyeball to the eyelids.  This may be
proved  by dissection, by  maceration, and  by its sloughing off
entirely along with the epidermis of animals that are subject to
this process, as the locust,  snakes, and  others.  On its posterior
face, it is covered by the membrane  of the  aqueous humour,
which may be rendered evident by steeping it in spirits of wine;
whereby the latter membrane is made more hard, and may be
torn off.
   The cornea, in a natural  state, is perfectly transparent, and
readily transmits the rays of light.   It consists of an indefinite
number of laminae, which  are placed one against the other like
the  leaves of a book, and are united  by a delicate transparent
cellular substance which permits the laminas to slide upon each
other.  These laminas are  kept moist and pellucid by an inter-
stitial secretion of a fluid  equally pellucid with themselves, the
abundance of which in health gives to the eye its brilliancy, and
the deficiency of it in  illness and in death causes the eye to look
dim and somewhat opaque.  Its evaporation, which no doubt is
continually occurring, is as constantly supplied by a fresh and
abundant secretion.  The motion of  the eyelids sweeps the resi-
duum, after the evaporation of its watery particles, from the sur-
face of the cornea: without this process, the residuum appears as
a thin layer or film of albuminous matter spread over the cornea,
when the eye is kept  open without winking for a considerable
time.
   The cornea has not the fibrous structure of the sclerotica, yet
the application of mechanical force to the eyeball  shows that it
is  stronger.   Neither has it vessels, conveying  red  blood natu-
rally, yet, in  a  state of inflammation^ its  capillaries dilate so as
to  admit  red blood, and deposite coagulating lymph between its
layers. It is common for anatomists to attribute a want of sensi-
bility to it in a  natural state:  as a general rule, this is fallacious;
for many persons, where the eyes are not  inflamed, suffer ex-
tremely from its being cut in  cataract, and sometimes  faint from
the pain, while others are truly unconscious  of  the incisions
made through it.   Of this opinion, I  have a  full assurance from 
THE BALL OF THE EYE.                  417
repeated observations on the practice of Dr. Physick, as well as
in instances in my own hands.

  The Choroid Coat (Tunica Choroidea, Vascutosa,) is  placed
immediately within  the circumference of the  solerotica,  and is
of equal extent.  At its posterior part it furnishes, for the pas-
sage of the optic nerve, a single annular opening, the margin ef
which is somewhat thickened, and perfectly distinct from  the
pia mater investment of the nerve, from which some anatomists
have desired to trace  this coat.   The anterior opening  of the
choroid is bounded by the ciliary ligament and by the iris.   On
its outer side may be seen an abundance of loose flocculent cellu-
lar substance which joins it to the  sclerotica.   Internally, it is
spread over the retina, but does not adhere to it.
   The choroid coat is closely fastened, at its anterior margin, to
the  corresponding part of the sclerotica, by a ring which sur-
rounds it, of a short compact cellular tissue.   This ring, called
the Ciliary Ligament, (Ligamentum Ciliare, Orbiculus Ciliaris,)
is from a line to two lines in breadth, and  may be  readily dis-
tinguished by its whiteness, contrasted with the dark colour of
the choroid.   It is intimately united to the latter, and seems to
form a part of its structure, whereby it is caused to detach itself
entirely  from the sclerotica, and to adhere, by  preference, to the
choroid when these  two membranes are separated.*   The iris is
set in the front  margin of the ciliary ligament, so that the scle-
rotica and the cornea may be peeled from the choroidea and iris,
without  impairing the continuity of the two latter. Just beyond
the junction  of  the two last, the ligament presents a small ridge
or elevation all  around, which is fitted into a corresponding fossa
at the circumference of the posterior face of the cornea.
   The internal face of the choroid coat, as well as its anterior
margin,  undergo  a  very remarkable  change  from the general
plan of this  tunic, by forming what is called the Ciliary Body,
(Corpus Ciliare, Corona Ciliaris.)   In order  to see  this  in the
most favourable manner, the  eye  should be laid  on  the cornea,
and its posterior half cut  away.  It will then be evident, that
just behind the  iris, and within the  circumference of the  ciliary

  * Fontana asserted that a circular canal was to be found in this ligament;
many examiners have failed in finding it, and its existence is denied. 
418                   NERVOUS SYSTEM.
ligament, the internal face of the choroid coat forms a conside-
rable number of radiated folds or little ridges, which  converge
from behind forwards and inwards.  These folds commence by
strias, almost imperceptible to the naked eye, which are in con-
tact  with the fore part of the vitreous humour, and with the ca-
nal of Petit, and thereby not only impress the neighbouring por-
tion  of the  tunica hyaloidea with their  shape, but even leave
upon it the black pigment with which they themselves  are  co-
vered.  These folds, when they get near the circumference of
the iris, coalesce one with  another, and terminate  in a conside-
rable number (from fifty to sixty, according to Soemmering,) of
processes, (Processus Ciliares,) the central extremities of which
are loose, and float in the aqueous humour.   Some of these pro-
cesses are longer than others.  As a whole, the ciliary processes
constitute a ring of radiating filaments, which are a line or more
in length, placed along side of, and in contact with, one another;
the external periphery of the ring adheres to  the ciliary liga-
ment, and through it to the greater circumference of the iris, so
that the ring appears, but fallaciously, to be continuous with the
iris.  In certain animals, as the  sheep, the radiated appearance
of the iris, on its posterior face, favours this notion still more.
The internal periphery of  the ring presents the central ends of
the  filaments detached from one another, and of a downy ap-
pearance; with the handle of a knife they may be readily pushed
backwards and forwards.  Generally speaking, the ciliary pro-
cesses are so much  concealed by the  iris, that they  cannot be
seen in the  living body through the cornea: in cases, however,
of extreme dilatation of the pupil  by narcotic applications, their
central extremities are brought into view.
   The choroid coat always appears, when uninjected, of a very
dark brown or black colour, arising  from a black paint (Pig-
mentum Nigrum) being  very thickly spread over the whole of
that surface of it which is  adjacent  to the retina, and being
also diffused through its  thickness.   This paint is more abun-
dant near the iris than posteriorly, being laid on there in flakes,
in the intervals between the ciliary  strias, and tinging  also the
 ciliary processes.  It may be removed in a considerable degree,
 indeed almost  entirely, by maceration, or by careful washing
 with a camel's-hair pencil.  It  is supposed to be an exhalation 
THE BALL OF THE EYE.
419
from the vessels.  Its particular colour is of a most  durable
kind.   According to  the observations of Bichat, the long-con-
tinued  action of light  upon it, when this pigment is transferred
from the choroid to a piece of paper, does not affect it; neither
is it changed by being submitted to very strong chemical agents,
as sulphuric, muriatic, or nitric acid, alcohol, or caustic potash.
This degree of indestructibility of colour is an invaluable pro-
perty,  and almost singular; for it is well known to the keepers
of medicinal articles,  that the colours of all of them yield to the
continued influence of light, and that they also become weaker
by the same cause.

   In regard to structure, the choroid coat is thin, soft and easily
lacerated: when cleared of its pigment by maceration, it is semi-
transparent, and is then seen evidently to consist of but one la-
mina; unless  we may be  disposed to consider as a second one
the pigment, naturally on  its internal face.  It has no appear-
ance of fibres in its composition, but, when  injected, seems to
consist almost wholly of arteries and of veins.
   The arteries  are branches of the  ophthalmic, and are called
 ciliary.   There are  two  Long Ciliary  Arteries, which pene-
 trate the sclerotic coat not far from the optic nerve, and pass,
 one of them, on the external and superior part of the choroides,
 and the other on its inferior and nasal side,  to the front of the
 eye.   In this course, they do not send off any branches of con-
 sequence till  they reach the iris, on which they are distributed.
 The Short Ciliary Arteries are  much more numerous than the
 others, and also smaller; their number sometimes amounts to
 twenty; the most of  them penetrate the sclerotica from behind,
 near the optic nerve  also.*  They quickly divide into a great
 number of branches, which depart at very acute angles,  and
 have  frequent anastomoses with one another.  These branches
 run forwards, nearly parallel, and,  at the fore part of the cho-
 roides, form  a very intricate intertexture, which is continued
 upon the ciliary processes, and communicates with the vessels
 of the iris.t
    The veins of the  choroid coat are also extremely abundant.

     * Soemmering, Icones Oculi Humani.        t Icones Oculi Humani. 
420
NERVOUS SYSTEM.
 They run from before backwards, and the branches which con-
 cur to form them, being adjacent with,and parallel to each other,
 for the most part, form large curves, the convexity of which is
 forwards; they, moreover, anastomose freely, and thereby pro-
 duce a vascular sort of net-work, filling upgthe concavity of some
 of the curves.  These veins, called the Vasa Vorticosa, are
 nearer the external surface of the choroides than  the arteries,
 and are assembled  into twelve or fourteen trunks, which, en-
 gaging in the  sclerotica, near its middle, run for some distance
 in its substance, and then, by their junction, are reduced to four
 or five in number.   The latter, disengaging  themselves from
 the eye, join,  subsequently, the ophthalmic vein.
   In addition  to the veins mentioned, the long ciliary arteries
 have their venae comites, which take a  course parallel to and
 adjoining them.  These  veins do not observe the  vortical ar-
 rangement of  the others; they bring back the blood of the iris,
 and terminate in the larger trunks of the others.
   This structure has been most cautiously explored by the ce-
 lebrated  Soemmering, and his observations have  tended very
 much to determine the opinions of anatomists concerning many
 parts of the eye.  A curious remark of his is, that " the human
 eye may be distinguished from that of animals by a  form of this
 vascular net work, entirely peculiar; for example, in the eye of
 the ape, its vascular tissue differs not only from that of the hu-
 man subject, but also from that of the dog, and still more evi-
 dently from that of the calf.   From which cause,  it would be
 as easy to distinguish with a  microscope, the choroides, well
 injected, of different animals, even a piece of only the forty-
 eighth part of an inch  in extent, as it is easy to distinguish  a
 poplar stripped of its leaves from an oak, a pear tree, an apple
 tree, or  any other tree, by the arrangement  of its trunk and
 branches.
  The choroides, on its internal face, is not smooth,  but velvety,
 which becomes  still more conspicuous when  the eye  is finely
 injected and examined  with  a microscope.   Meckel considers
the appearance to depend upon its very fine tissue of vessels.
This surface is  called  Tapetum.  In the bullock, and some
other animals,  at a particular part, it presents a shining, silvery
appearance, and may be  torn off from the external  surface. 
THE BALL OF THE EYE.
421
Ruysch attributed two laminas to the choroid membrane in the
human subject, the internal of which was called after his name,
but the distinction is now generally  abandoned.

  The Iris is  a circular plane placed at the  front of the cho-
roides, and  having, in its centre, a round opening called the
pupil (pupilla.)  Its external circumference as stated is attached
to the ciliary ligament, and by it to  the choroid coat, and is ex-
actly at the junction of the cornea with the  sclerotica.  Pro-
fessor Soemmering has bestowed much  attention in ascertain-
ing whether this membrane is perfectly  flat or somewhat con-
vex in  front,  and, by repeated  observations, carefully made,
has assured himself that it is flat.*  My own observations and
preparations have induced me to believe that in many cases it
will be found  slightly convex in front, as Petit asserted more
than a century ago.  In a moderate state of dilatation, its na-
sal or  internal border is somewhat  narrower than its external
or temporal.  With the exception of its external circumference,
every part of the iris  is void of any attachment; by which ar-
rangement it moves freely in the aqueous humour, so as to con-
tract or dilate the pupil, according  to the quantity of light ad-
mitted  upon the eye.
   The  iris, with the exception of its central or pupillary cir-
cumference, where it is thinner than elsewhere, is  much thick-
er than the choroid coat.   The posterior face of the iris, some-
times  called uvea,  is covered in  great abundance with  pig-
mentum nigrum.  When this is removed by maceration, which
may be readily done,  the membrane becomes semi-transparent.
Its anterior surface  is the seat of the  colour, which characterizes
every individual's eyes.   There are but two of these  colours,
light blue and orange, the predominance of one or the  other of
which, assisted by the dark ground  on the back of the iris, give^
the cast of hue to the eye.  The front surface, when examined
on the  living eye with the microscope, is seen to  be downy  or
flocculent, and is traversed by  filaments forming an intertex-
ture, some of which are circular, others oblique; and others ra-
diated.  This arrangement is remarkably distinct in the eye of
the seal.
                     * Icones Oculi Humani.
   Vol. II.—37 
422
NERVOUS SYSTEM.
  The power which the iris has  of dilating the pupil when
there is  but little light, and  of contracting  it when there is
much, has induced many anatomists to think  that it  is formed
of muscular radiated fibres, which by their contraction produce
the  first motion, and of circular ones which  produce the last.
Among these anatomists may be mentioned, Ruysch, Morgag-
ni, Zinn, Sabatier.  Ruysch  asserted that the radiated fibres
extended from the greater circumference of the iris to the pupil,
and were fixed there by very delicate tendons.  The late Doc-
tor  Monro, of Edinburgh,  has described particularly  the circu-
lar fibres, and a preparation of the bullock's eye which belonged
to him is still exhibited there, where these fibres are found around
the  margin of the pupil.   The  several fibres can only be seen
distinctly, when the pigmentum nigrum is washed away.  De-
mours and Meckel deny the existence of the radiated  fibres.
The late distinguished  Professor Wistar taught that the  con-
traction of the  pupil was produced by circular fibres, and the
dilatation  of it by its elasticity.   In objection to this, the late
Dr.  Physick remarks, that as elasticity is as much a properly
of dead as of living matter; in death, therefore, we  should al-
ways find the pupil dilated from the want of active contraction
in the circular fibres; also, in cases of concussion of the brain,
where there is a sudden loss of sensibility and of muscular mo-
tion, the pupil should be invariably dilated; but the fact  is, that
the  pupil remains just in the same state that  it was at the mo-
ment of the accident.*
  Notwithstanding the extreme sensibility and mobility of the
iris  on the admission of light, one is  occasionally astonished to
find  it not contracting when instruments are  applied to it, as I
have had an opportunity of twice observing,  upon the removal
of a considerable portion of it, in making an  artificial pupil for
opacity of the cornea.   In these cases, upon  the letting out of
the  aqueous  humour, it became quite as flaccid as we are ac-
customed to see it in our  dissections.  The same remark has
been made by Mr. now Sir Charles Bell.
  The Blood Vessels of the Iris are principally branches of the
Long Ciliary, which have been alluded  to.   Each of the two

  *  It would appear that the question of the muscularity of the iris has been
settled almost conclusively by Mr. Bauer.  See Ph. Trans, for 1822. 
THE BALL OF THE EYE.
423
Long Ciliary Arteries having gained the greater circumference
of the iris, bifurcates; the bifurcation runs along this circumfe-
rence, meets, and joins with the corresponding one of the other
arterial trunk.   From the circle thus formed there proceed ra-
diated branches, that run towards the pupil, and form around
its margin, by their frequent anastomoses, a  fine vascular net-
work.   The  radiated branches themselves give  off collateral
branches, which  supply  the  intermediate spaces of the iris.*
The veins of the iris are also numerous, but cannot be quite so
distinctly seen:  they enter into the long ciliary veins, and also
into the vasa vorticosa.
   The  nerves of the Iris belong, in part, also to the choroid
coat, and are classed under the term Ciliary, (Nervi CMares.)
They arise from the ophthalmic ganglion, and from the trunks
contributing thereto, and are about  twenty in number.   They
penetrate  the posterior  part  of  the sclerotica obliquely, and
then run  forwards  between  it and the choroides.   Having
reached the  posterior  part  of the ciliary ligament, they pene-
trate it, and  distribute their filaments in its substance, after the
same fashion that the trigeminus nerve is  divided  in its gan-
glion.  This circumstance  has given occasion to Soemmering
to consider the ligament as a true ganglion, and to call  it An-
nulus Gangliformis.   The nerves then get to the front of the
iris, and are there distributed as  white radiating filaments; in
the  course of which maybe observed small nodes, supposed by
Meckel to be Ganglions.
   The trunks of the ciliary nerves depart from the common
form of such bodies, by being flattened instead of cylindrical:
they are small, and resemble sewing threads.   From their num-
ber, the iris  is probably  more abundantly supplied with nerves
than any other organ of the body.
   The Retina forms the third coat of the eye, and lines the in-
 ternal face of the choroides almost in its whole extent.   The
optic nerve  having passed through the sclerotica, terminates on
 its inner  side by a bulb or button-like end, from the circumfe-
 rence of which the retina begins to  expand, and maybe traced
satisfactorily as far as the commencement of the ciliary plaits of
the  choroid  coat, where  it terminates by  a straight edge, some-
                 * Soemmering, Icones Oculi Humani. 
424
NERVOUS SYSTEM.
what thickened.   Just at the edge, the  retina adheres to the
vitreous humour, and is supposed, erroneously by some anato-
mists, as Bichat and Monro, to be continued on to the circum-
ference of the lens.  Repeated  dissections, and the  substantial
testimony of Soemmering,*  have satisfied me  that the retina
cannot  be fairly traced beyond the greater circumference of
the impressions made on the vitreous humour by the ciliary
striae of the Choroides.   When the eye is slightly macerated,
the retina always parts from the vitreous humour at  this  line;
moreover, when  its structure is still more slightly changed by
freezing and then thawing, the  retina manifests a decided pre-
ference to separate there, and, under the most careful dissec-
tion, it  is  very difficult to prevent it.  In addition to these con-
siderations, there is a well marked change of colour at the line
mentioned: in front of this line, the  surface is transparent when
cleaned from the pigmentum nigrum; whereas, if it were retina,
it should be the colour of ground glass, as is usual in the  dead
body: also the veins of the retina  never trespass beyond this
line, but are seen to cruise  along it.
  Most anatomists teach that the retina is an expansion of the
optic nerve.  Bichat believed that  the latter terminated at the
bulb, and  that the retina was another part of the structure, but
still consisting of the same sort  of nervous matter.  The latter
opinion is probably the  more strictly correct, because there i-s
more pulpy matter in a section  of the retina than  can be found
in the same length of the optic nerve; also, if the retina were
simply an expansion of the nerve without any addition of mat-
ter to it, it should, from  its hollow globular shape, be thinner in
the middle, where it is most expanded, than it is where the ex-
pansion first begins at the  bulb of  the optic nerve, but this is
not the  case.
  The retina does not adhere to the  choroid coat, neither to the
vitreous humour which it encloses, except at the line mentioned:
when this line of attachment is broken, the retina quickly col-
lapses.
  The texture of the retina  is extremely soft and pulpy; in the
living state,  it is probably nearly transparent,  but this  can
only be conjectured  from the readiness with which the vessels
Icones Oculi Humani. 
THE BALL OF THE EYE.
425
of the choroid coat can be seen in animals destitute of pigmen-
tum nigrum.  It is composed of two laminas, of which the ex-
ternal is nervous, and the internal, or that next to the vitreous
humour, is formed of a fine reticulated cellular membrane with
blood vessels  running  through  it.  The  external lamina  may
be removed by a camel's hair-pencil, or  by slight putrefaction
and  washing, so as  to leave  the internal  entire.   The cele-
brated John Hunter  succeeded, however, in separating the two
laminas fairly  from  each  other, and preserving them, so  as
to show their  difference.  This specimen  may be considered
unique, and every way deserving of the source from which it
proceeded.*
   Exactly  in the axis  of  the  eye, or at its centre, posteriorly,
consequently, about  a line and a half from  the outer side of the
bulb  of  the optic nerve,  Soemmering discovered,  in  1791, a
yellow spot (Macula fiava) of a line in diameter, with a small
 hole in its  middle, made by a deficiency of medullary matter.
 From the optic nerve there goes, towards the foramen, a small
 fold of the retina, pointed at its internal  end, and obtuse or bi-
 furcated  externally.   Unless the  eye  be  fresh, these things
 cannot be  seen  distinctly, for the evaporation  of the  aqueous
 humour  causes  a collapse or  wrinkling of the retina, which
 obscures them.   But, in a perfectly fresh eye, which is well
 managed, they may be  seen both from  before and behind.   It

   * The fact was communicated to me by the late Dr. Physick, who studied un.
 der Mr. Hunter, and frequently saw the  preparation.
   The Retina is said by Langenback to have three coats.  1st. An external gra-
 nular coat.  2. Ehren berg's filamentous nervous coat: and 3d. A vascular coat,
 consisting of blood vessels, united into  a delicate membrane by much cellular
 substance.  Whether the filaments of the nervous coat be plain, cylindrical, or
 nodulated ones, is unsettled.  The granular layer terminates at the macula flava
 by a sharp edge; and it ends also at the border of the ciliary ligament.  Trevi-
 ranus, also, admits the division of the optic nerve into cylinders, and of extreme
 minuteness.  The granular layer is said by Gottshe  not to be found in recent
 eyes; he also says that, a perfectly recent retina has the appearance of a thatched
 roof; that is little cylinders, the ends of which project out, like a staff. Michaelis
 admits the division of the retina into three layers, as above, and adds a fourth, it
 being the tunica Jacobi.  The internal layer he considers as serous.  The fasci-
 culi of the nervous coat are best shown by means of the spirit of creosote.  The
 filaments he estimates at a diameter of the 33V0 of a line.  The serous coat is
 best seen by the use of diluted sulphuric acid.  Muller's Report on Nervous Sys-
 tern, p. 237.
                               37* 
426
NERVOUS SYSTEM.
was thought, for some time, that the yellow spot and the fora-
men were peculiar attributes of the  human  being: more  ex-
tended and successful  observation has  corrected this mistake,
by detecting them in several classes of animals.*
  In the centre of the optic nerve, where it enters the eye, is
a foramen for the passage of the artery and  vein belonging to
the retina.t   These vessels ramify, by  a  few branches, on  the
internal surface of the  membrane, and form a sort of circle sur-
rounding  the  yellow  spot.  Neither  the branches of  the  ar-
tery nor  of the vein  communicate  with  those  of the cho-
roides; and, as observed, never go beyond what we just con-
sidered as  the anterior  margin of the retina, but rather  run
along it.

  Interposed between  the retina and  the choroides, is a most
delicate serous membrane, which was discovered by Mr. Jacobs,
Demonstrator of Anatomy  in  Trinity College,  Dublin.   By
preparing  the retina in  the  usual way, and then floating  the
eye in a saucer of water, this membrane may be turned down
with the handle of a scalpel from the optic nerve to the termi-
nation of the retina.   It  is supposed to be the seat of  the ossi-
fications which are sometimes met with in the eye.


                   Humours of the Eyeball.,

  The  Vitreous Humour (Humor  Vilreus,  Corpus Vitreum,)
occupies, with the exception of a very small part  just behind

  * In a careful examination of the eye of Williams the murderer, executed in
the  Moyamensing Prison Aug. 9, 1839, I found (in three hours after the  drop
fell, the eye consequently being perfectly fresh,) the retina, in both eyes, of the
colour of oiled white paper or ground glass: it was  seen distinctly to terminate
at the beginning of the ciliary plaks  of the choroid. The spot of Soemmering was
seen, but it was of a sea green, oval, a line in length, the centre marked by aa
olive spot: no foramen was seen satisfactorily.  The fold of the retina, running
to the entrance of the optic nerve, was very distinct,, as well as the  button-like
appearance of the nerve at this point.
  t The point where the central artery of the Retina enters,is called the Macula
Lutea.  Michaelis asserts, that around it the filaments of the retina are arranged
in arches, of which one part meets in the macula lutca, the next in succession
converge regularly towards  a line stretching from the macula lutea.   Muller ut
Supra. 
T-HE BALL OP THE EYE.
427
the iris, the whole of the space  posterior to the latter.  It is,
therefore, very nearly globular;  is in contact the greater part
of its extent with the retina, at least  as  far as the latter mem-
brane proceeds; in front it is in contact with  the crystalline
humour, and from the margin of  the retina to the circumference
of the lens it is in contact with the ciliary body, meaning there-
by the ciliary strias and processes of the  choroides.
   Two parts compose  the vitreous humour,—the hyaloid mem-
brane and a thin fluid.  In a natural state they are perfectly
transparent, and, therefore,  cannot  be readily distinguished
from each other; but by immersion in spirits of wine the mem-
branous portion is brought  to the colour of ground glass, and
may then be  studied  very advantageously.  The  membrane,
though extremely delicate, is generally strong enough to permit
the whole vitreous body to be suspended in the air by a thread
passed  through it, and  it may also be momentarily held up with
a pair of forceps.*

   The  Tunica Hyaloidea may be traced as a complete capsule,
forming the periphery of  the vitreous humour;  and from  the
internal face of this  capsule there  proceeds a great number of
partitions dividing the  whole cavity into cells of various mag-
nitudes and forms.   Some anatomists, who have frozen the eye,
and then picked out the pieces  of ice from the cells, have got
the idea of their being  all cuneiform, and of their edges pointing
forwards.  Our preparations in  the anatomical cabinet are per-
fectly satisfactory in  exhibiting the  existence of an  arrange-
ment of cells, but do not manifest a regular cuneiform shape in
 them.
    When the capsule of the tunica hyaloidea has got to the dis-
tance of two lines, or thereabouts, from the circumference of
the lens, it divides into two  laminas,  which reunite at the  cir-
 cumference of the lens.  They then divide again, and one goes
 before  the capsule  of the  lens,  and  the other behind it.   The
 space between the two layers, around the circumference of the

   • In Williams the murderer, executed here, as stated before, I found on the
 front of one hyaloid, just at the side of the lens an opacity of three by six lines,
 resembling an opacity of the cornea, it was just where the tunica hyaloidea is in
 contact with the ciliary plaits of the choroid and was first mistaken for a metallic
 like surface of the lather, as the tapetum of the lower animals. 
428
NERVOUS SYSTEM.
lens, is the canal of Petit, and is that part of the tunica hya-
loidea which is impressed by the ciliary strias and ridges of the
choroides.  At intervals,  passing in a radiated manner  from
the exterior to the interior circumference of the canal, there is
a  sort of  shortening or  constriction of it, producing partial
septa in its cavity; so that when the canal is inflated,  it seems
to consist of a series of small cells, arranged circularly.   The
cells of the colon will give some idea of this arrangement, though
they are produced in an entirely different manner.
   The fluid part of the vitreous  humour, by analysis, gives out
98.40 water, .16 albumen, and the remainder is saline.  In con-
sequence of the very small quantity of albumen in it, neither
acids nor heat coagulate it to a  striking degree.
   The vitreous humour is supplied with a branch from  the cen-
tral artery of the retina.  This branch does not convey red
blood,  but only serum, except in the fcetal eye.  It may be in-
jected, at almost  any age, with size, coloured with  vermilion;
but is then, of course, put very much  on the stretch.  It hay
been well  described by  Zinn.  It penetrates  the  vitreous hu-
mour near the optic nerve,  and is disseminated  by very fine
branches on the periphery, and  on  the  internal cellular struc-
ture of the tunica  hyaloidea.   M. J. Cloquet has described par-
ticularly one branch, which, running through the  centre  of the
vitreous humour, in an appropriate canal, is spent by small ra-
mifications upon the posterior part of the capsule of the lens.
   Some anatomists* speak of a fluid between the tunica hya-
loidea and the retina: when it does exist, it  in all probability is
the fluid of the vitreous  humour, which has  strained  through
the tunica  hyaloidea after death.

   The  Lens (Lens Cryslallina) or the Crystalline Humour, as
it  is very  generally called, is placed immediately behind the
pupil, in a  depression on the  front of the vitreous humour.  Its
shape  is that of a doubly convex lens, of which the posterior
convexity  is greatest, being the section of a sphere whose dia-
meter is from four to five lines, while  the  anterior convexity
is in the proportion of a  sphere  of from six  to nine lines.   The
usual breadth of the lens  is about three and a half lines.  It,
* Bichat, Anat. Descrip. 
THE BALL OF THE EYE.
429
 however, varies its shape in a remarkable degree at the differ-
 ent periods of life; immediately after birth it is spheroidal, in
 about six years afterwards its lenticular shape  is well marked,
 and,  subsequently, it becomes more flat and thin.
   The lens naturally is perfectly transparent.  In the greater
 part of its thickness it has the consistence of half dissolved g!ue,
 but its centre is much more solid; this change, however, is ef-
 fected successively.   When it is subjected to the mineral acids,
 to heat, to alcohol, and several other agents, it becomes much
 more solid throughout; it may then be separated, like an onion,
 into a series of concentric lamellae, subdivisible into longitudi-
 nal fibres.  Besides these, there are fibres more or less oblique
 which hold the lamellae together.   These arrangements prevail
 from the centre to the circumference of the lens; and between
 the laminas there is a diaphanous humour resembling that  be-
 tween it and its capsule.*
   The lens is invested by a capsule which is a complete  sac,
 having exactly its shape, but separated from it, to a very in-
 considerable extent, by the transparent humour just alluded to,
 called the  Liquor  Morgagni.  The capsule is covered in front
 by a layer of the tunica hyaloidea adhering very closely to it,
 but which, in one instance, I was enabled to peel off partially
 in the eye of a sheep, from one side to the other.  The capsule
 is covered, in like manner, on  its posterior face by the  tunica
 hyaloidea; but the two may be separated there  more  easily,
 according to the observations of Bichat.  Some of the most
 distinguished continental anatomists are decidedly in favour of
 the capsule of the crystalline  being a complete bag; but it is
rather unsettled whether the exterior margin of the capsule
bounds the lesser circumference of the canal of Petit, or whe-
ther the two layers of the tunica hyaloidea unite previously at
the circumference of the capsule.  The latter seems to  be the
opinion of M. J. Cloquet.  The rate Dr. Physick, in some cases
of membranous cataract, has  succeeded in drawing out the
capsule entire, so as to exhibit its whole extent when floated
in water.
  The capsule in front of the lens is much thicker than the  tu-
nica hyaloidea, and its difference of character  from the latter
* J. F. Meckel. 
430
NERVOUS SYSTEM.
appears to me to be very strongly marked; for, notwithstand-
ing its immersion in spirits of wine, it retains its transparency.
It is hard and elastic, and when clipped with the scissors, gives
nearly the  same sensation as  the thin paring of a finger  nail
would; or, as  has been observed by Haller, it, in this  respect,
resembles  the cornea.  The analogy with the cornea ceases,
however, at this point; for the  cornea has always so much al-
buminous  matter in it as to be rendered turbid when it is
immersed   in alcohol.  The posterior section of the  capsule
of the lens, is not so well marked either by its thickness or
specific characters as the  anterior, yet our preparations in
the University demonstrate its existence equally as  conclu-
sively.  It is more  assimilated to  the nature of the  tunica hy-
aloidea.
  In the injected fcetal eye, the artery of the tunica hyaloidea
which comes from the central one of the retina, is seen to  fur-
nish several minute ramifications to the posterior face of the
lenticular  capsule; some of its branches also go to the  front of
the capsule, but the latter part is furnished principally by arte-
rioles from the ciliary body of the choroides.  The two sets of
arteries anastomose with each other; some of the latter  are also
spent upon the membrana pupillaris.
  The point is yet doubtful whether any of these arteries  pe-
netrate into the body itself of the crystalline humour. Ruysch,
Albinus, and Haller, assert the fact  of their having seen  and
injected them  in the human species and  in  animals, and J. F.
Meckel admits their testimony.   Yet there are not many ana-
tomists who can corroborate it by their personal observations.
It is sufficiently reasonable to admit it; for without, we cannot
conveniently account for the growth and nutrition of the lens,
as well as  the morbid changes which occur in it.  It should be
observed that  if  this vascular  connexion do exist, it is a very
weak one: for the lens seems to be  simply surrounded by its
capsule without adhering  to it.
  Some veins which discharge into  the veins of the  choroid
coat,  have been  observed by Walter* on  the posterior part of
the capsule.  It should be continually borne in mind that  nei-
ther the arteries nor veins of the healthy crystalline, nor of its

                    * De Oculis.  Berlin, 1778. 
THE BALL OF THE EYE.
431
capsule,  convey red blood:  in which respect they correspond
with the  hyaloidea;  for, if this were the case, vision would be
very  much disordered  by  it.   It may be  that the moats or
specks seen in ophthalmia arise from the grosser particles of the
blood getting into these serous vessels, by the dilatation of the
latter.
  The Lens and its Capsule are  devoid of nerves, at least none
have  been as yet traced into them.

  The Aqueous Humour  (Humor Aquosus) occupies  the space
which is between the anterior face of the crystalline capsule,
and the posterior face of  the cornea.  This space is unequally
divided by the iris into two chambers, of which the anterior ia
in front of the latter membrane, and the posterior behind it. In
consequence of the  convexity of the lens, the posterior cham-
ber has Jbut very little depth just behind the pupil;  but its space
is augmented at the circumference of the crystalline, so as to
leave room for the  floating  of the ciliary processes and for the
motions  of the iris.  The  posterior chamber is, therefore, a cir-
cular vacuity;  the  centre of which, from the projection of the
centre of the crystalline, has scarcely any appreciable depth.
The  anterior chamber, in  its shape, resembles the segment  of a
sphere:  its depth depends essentially on the size  and the  pro-
jection of the cornea.
   The aqueous humour is perfectly  transparent, and almost as
fluid  as water.  The analysis of Berzelius exhibits 98 parts of
water, 1 of hydrochlorate and lactate of lime, 75  of some ani-
mal matter soluble in water, and a very small quantity of albu-
men.  From the latter circumstance it will be understood  how
this fluid refuses to coagulate on the addition of alcohol or of
mineral  acids to it, and  is  only rendered  in a  very  slight de-
gree  turbid by them.  The rapidity of the  exhalation of this
fluid  is remarkable; when the whole of it is lost in the opera-
tion for cataract, it is regenerated in from twenty-four to thirty-
six hours.  Its source has been sought for in supposititious canals
and glands, but the more probable opinion is, that it may come
 from any or all of the exhalent arteries of the chambers of the
  eye
   Like the other two humours of the Eye, the  aqueous is fur-
 nished with a capsule, but  whether  it is complete or  not is yet 
432
NERVOUS SYSTEM.
undetermined.  By immersing the eye in hot water, or in alco-
hol, this capsule may be readily detected on the posterior face
of the cornea, and to the greater circumference of the iris; it
may even be traced for some distance on  the front  surface of
the latter.  Some of the French anatomists, as Demours,* De-
scemet, and  J. Cloquet, have asserted that  it continued also
through the pupil to line  the posterior chamber.  An opinion
like this, from the extreme tenuity of the part, must be rather
the result of conjecture than of accurate observation: it has,
therefore, never found its way with full force into  the writings
of anatomists.  The condition of the pigmentum nigrum on the
posterior face of the iris, and on  the  ciliary processes, would
seem to be an objection to the existence of this capsule in the
posterior chamber of the eye.  But, if it really does exist there,
as is pretended by  M. Portal, who supposes it to be  derived
from the tunica  hyaloidea, its structure is  incomparably more
delicate than that part on the cornea, and, indeed, is merely glu-
tinous.

  The Chambers of the Eye, till the seventh month of fcetal ex-
istence, and sometimes later, are perfectly separated from each
other by the Membrana Pupillaris, called so from its position in
the pupil of the iris.   It was discovered in 1740 by Wachen-
dorf, and is sometimes called after his name.  It is a thin, deli-
cate, and transparent membrane, which is stretched across  the
pupil from its circular margin, and may, by its colour, be readily
distinguished from the  iris, when it has been made  somewhat
turbid  by alcohol.
  The Membrana Pupillaris consists, according to M. J. Clo-
quet,*  of two laminas placed back to  back, of which the fore-
most is a continuation of the membrane which  lines the ante-
rior chamber of the eye, and the hindmost of that which lines
the posterior chamber.  According to this,  it may be noted
that each chamber has its distinct capsule.  This membrane is
very vascular; some of its arteries are those which subsequently
form the internal arterial circle of the iris, and  they radiate from

  • Demours, Lettre, 1767.
  | Journal Universelle des Sc. Med. Paris, 1818. Mem. sur la Memb. Pupill.
Paris, 1818. 
THE EAR.
433
the circumference to the centre of the membrane; others come
directly from  the long ciliary arteries and others again from
the arteries of the crystalline  capsule.  These several vessels
are found principally on its posterior face.  Its veins  have not
been observed.
   This membrane first shows itself about the third month of
fcetal existence, and is most  perfect at the seventh;  from the
latter period it begins to decline, by disappearing from the cen-
tre to the circumference.  At the ninth month it consists only
in a few loose flocculent masses  adhering to the pupil.   M. J.
Cloquet has ascertained  that its vessels do not participate in its
destruction, but that the arches which they form are  retracted
to the margin of the pupil, and  there form the lesser arterial
circle of  the  iris.  From the observations of Drs. Jacob  and
Tiedemann, it1 appears that  traces of the membrana  pupillaris
exist for ten or fifteen days after birth.  The latter, in one case,
injected its vessels in a fcetus at full term.*
                    CHAPTER  III.

                       OF THE EAR.

  The ear, the organ of hearing is  placed  principally within
the petrous portion of the temporal bone, and consists in the
External Ear, or Auricle,  the Tympanum, and the Labyrinth.


               SECT. I--OF THE EXTERNAL EAR.

   The position of this portion of the organ is familiar to every
one.  It is useful in collecting the rays of sound, and in con-
veying  them to the more  internal parts.  It is formed by the
structure, exterior to  the petrous bone,  called, in  common lan-
guage, the Ear; and by a bony canal which leads internally to
the tympanum.  The basis of the first portion is cartilaginous,

                  * Am. Med. Jour. vol. i. p. 192.
   Vol. II.—38 
434
NERVOUS SYSTEM.
on which  circumstance it depends  for the permanency of its
shape.
  The ear, of common language, is divided into two parts, Pin-
na* and Lobus: the former is the most extensive, as it compre-
hends all the cartilaginous portion: the latter is attached to  the
inferior margin of the former, and, having no cartilage in its
composition, is soft and pendulous.

  In the centre of the external ear  is a deep depression called
the Concha; in the bottom of it is the orifice of the canal lead-
ing to the tympanum, and called Meatus Auditorius Externus.
The circumference of the pinna is convoluted into a scroll called
the Helix, and commences just above the meatus by a ridge.
This ridge divides the concha into two  unequal cavkies, of
which the lower is the larger.  The scroll becomes gradually
less prominent, till it  terminates at the posterior inferior part of
the pinna, in the lobus.
  The Antihelix is the slightly curved and  vertical eminence in
the middle of the pinna : its lower part forms the posterior boun-
dary of the concha, and its upper part bifurcates into two small
ridges, between which there is a  depression called the Scapha.
Between the antihelix  and the posterior half of the helix, is an
oblong depression called the Fossa Innominata.
  The Tragus is  a cartilaginous elevation  of the pinna placed
in front  of the concha, and inclining somewhat over it; opposite
to it, at  the inferior part of the concha, is the Antitragus.
  The cartilaginous plate, upon which the external ear depends
for its shape, is of a thickness very nearly uniform; of course,
the ridges and depressions on its  exterior surface  have  corre-
sponding depressions  and ridges on the side next to the head. It
is interrupted at  several places  by fissures; for example, there
is one of considerable  size filled  up with  ligamentous matter,
which separates the upper margin of the  tragus from  the  be-
ginning  of the helix: there is another between the lower extre-
mity of the  antihelix and the antitragus.   In  the  tragus, there
are two, and sometimes three, small narrow ones, said, by San-
torini, to be filled with muscular fibres; but the latter assertion
From some resemblance to a certain shell fish. 
THE EXTERNAL EAR.
435
does not correspond with the observations of subsequent anato-
mists, as the matter appears fibrous.
  The external ear is united to the side of the head by three li-
gaments.  The anterior arises from the  root of the zygomatic
process above the articulation of the lower jaw, and is inserted
into the pointed production of cartilage on the fore part of the
helix.  The  posterior arises from the swell of the temporal bone,
which runs into the front margin of the base of the mastoid pro-
cess, and is  inserted into the convex side of the concha, at the
beginning of the  meatus auditorius.  The superior arises from
the temporal aponeurosis, and is inserted into the upper part of
the concha.   These  ligaments lie immediately below the mus-
cles destined to move the ear.

  The Meatus Auditorius Externus, is, in the adult, an inch in
length,  reckoning from its external orifice to the membrane of
the tympanum, which closes it inwardly.  It is about three lines
in diameter, is ratheroval than cylindrical, and somewhat smaller
in the middle than at either of its extremities.  It runs inwards,
with a slight inclination forwards;  the  exterior  half is formed
by the cartilage of the pinna, and the internal half by the tem-
poral bone: it departs  from the horizontal course,  in  being
curved  at its middle where the two sections join.  This curva-
ture has its  convexity upwards, so that when we wish to look to
the bottom of the canal, the external ear must be pulled upwards
and backwards.
   The cartilaginous portion of the  meatus auditorius is formed
by a triangular piece springing from the base of the tragus and
from the inferior anterior part of the concha.   This portion  is
nearly a tube, but is  interrupted above and behind by the inter-
vention of  a dense fibrous  tissue, continuous with, and indeed
the same with that which joins the helix and the tragus.   The
internal margin of the  cartilaginous meatus forms a point be-
low; and adheres closely by ligament to the asperities on the
margin of the bony meatus.  If there were no fissures in the ex-
ternal ear,  it would, therefore, be almost  immoveable.

   The skin covering the external ear is more delicate  than  in
most other  parts of the surface  of the  body.   Its sebaceous 
436
NERVOUS SVSTEM.
glands or follicles are very abundant, and in infants secrete free-
ly their peculiar  fluid.   When a  slight inflammation occurs,
this discharge is frequently purulent without erosion.  A dupli-
cation of the skin, containing a delicate granulated adeps with
some fibrous matter, constitutes the lobe of the ear.
  The skin, after lining the concha, descends into  the  meatus
auditorius, and lines it also as well as the external face  of the
membrane  of the  tympanum.   It adheres  moderately  to the
cartilaginous part of the tube, and more tenaciously to its fibrous
portions: between it and the latter are found many small reddish
bodies, generally oval, the  Glandulae Ceruminosas,* from which
proceeds the earwax.j  The skin is extremely thin in the bony
meatus, adheres closely to its periosteum, and is highly sensible:
where it forms the exterior layer of  the membrane of the tym-
panum, it may be detached from  the latter with the slightest
force, and seems  to be converted almost entirely into  cuticle.
A slight maceration or incipient putrefaction frequently enables
one  to draw the cuticle out  entire from the meatus, so that it
looks in shape like the finger of a small glove.
  The dermoid lining of the meatus, at its external orifice, is
studded with fine hairs, which serve to keep out small  bodies
that may be floating in the air.  A considerable  number  of
small pores are also seen  in it, which  are the orifices of the
ducts of the ceruminous glands.   The  discharge of the latter,
when first  secreted, is thin and white: by evaporation, it be-
comes thick and yellow, and  by accumulating obstructs the
passage.

  There are several small muscles situated on the external ear,
which are for the most part so feebly developed that they cannot
always be found, and when they do exist they seem more like
the rudiments of what is well marked in animals, than intended
for a special purpose in the human body.

   1.  The Helicis Major is an oblong fasciculus, situated on the

  * Duverney, CEuvres Anatomiques.
  ■j- They are placed, according to Buchanan, for  the major part, in the middle
and superior face of the meatus, and their number he estimates at from one to two
thousand.  Physiolog. illustrations.  1825. 
THE EXTERNAL EAR.
437
front of the helix.   By its lower end it is attached to the point
of cartilage on the front of the helix, and its other extremity ex-
tends to  the lop of the latter.

  2. The Helicis Minor is a small square fasciculus, also on the
front of the helix, between the folded margin of the latter and
the inferior half of the helicis major.

  3. The Tragicus is a square fasciculus, on the  front surface
of the tragus, near its margin: its  upper extremity sometimes
runs into the helicis major.

  4. The  Antitragicus is  a small oblong  fasciculus,  which
arises  from the upper extremity of the  antitragus, and going
upwards it is inserted into  the inferior extremity of the anti-
helix.

  5. The Transversus Auriculas is on the internal surface of the
pinna.   It  arises from the prominence of the concha, and is in-
serted into the hollow dorsum of the antihelix.

  There are some other muscles which may be uniformly found,
and are intended to move the external ear upon the side of the
head, though from the want of exercise there are very few in-
dividuals capable of making them contract.  They are as  fol-
lows :—

  1. The Attollens Auriculas is placed on  the side of the head
beneath the integuments: it is a broad, thin, and somewhat  tri-
angular muscle, which arises  from  the inferior margin of  the
tendon of the occipito-frontalis, and  from the temporal aponeu-
rosis.  It becomes narrower in its descent, and is inserted ten-
dinous into the upper  end of the pinna by the elevation corre-
sponding with the scapha.
  Its name implies its action to be  that of raising the pinna.

  2. The Retrahens Auriculas, consists in two or three oblong
fasciculi, placed parallel, and  one above  the other.  It arises
from the mastoid portion of the temporal bone, above the mas-
                            38* 
438
NERVOUS SYSTEM.
toid process, and is  inserted tendinous into the convex side of
the concha near the meatus auditorius.
  It draws the pinna backwards.

  3. The Anterior Auriculas is a small quadrangular slip, just
above the root of the zygomatic process.  It arises from the
temporal fascia, and is inserted tendinous into the fore part of
the helix just above its beginning.
   It draws the pinna forwards and upwards.


                SECT. II.—OF THE TYMPAIVUM.

   The Tympanum is the middle portion of the organ of hear^
ing, being interposed between  the meatus auditorius and the
labyrinth.   Its depth is about three  lines, its antero-posterior
diameter about six, and its vertical diameter rather more, though
from the general inequality of the cavity, and its communication
with adjoining cavities, it is not easy to fix upon very precise
measurements.
   The Membrana Tympani, is a complete membranous septum,
interposed between the meatus externus and the tympanum.  It
is placed very obliquely, so that its upper edge inclines outwards,
and its under edge inwards; the latter, therefore, forms a very
'acute entering angle with the inferior part or floor of the meatus,
and  gives to  that portion of the meatus an  additional length,
which renders it difficult to  see to its  bottom.  The membrane
of the tympanum is  nearly circular, and has  its  circumference
adhering  very closely to the external  orifice of the tympanum.
It is slightly tense, and has its middle drawn inwards by  being
attached to the handle of the malleus.
   The membrani tympani consists of four laminas; the two ex-
terior of which, being the cuticle and the cutis vera, which line
the meatus auditorius,  are easily detached,  as  mentioned be-
fore,, and  seem scarcely to  adhere  to the  layer below.   The
third layer is  the proper membrane, and is distinguished  by its
dryness and by its transparency.  Sir Everard Home was ena-
bled to detect radiated muscular fibres, forming it in the ele-
phant.*  In the human subject, its fibrous character is best seen

             * Philosophical Transactions, for 1800. London. 
THE TYMPANUM.
439
on its internal face, but the radiated arrangement is not so dis-
tinct.  Caldani considers it as formed by filaments, decussating
each other at right angles, and intermixed with blood vessels.*
The internal  layer is a continuation of the lining membrane  of
the tympanum;  it is  separated with some  difficulty, owing  to
its tenuity.
  The proper membrane of the  tympanum, when successfully
injected, exhibits a high degree  of vascularity ;f  though, in its
natural state, but very few red blood vessels are seen in it.

  The floor of the tympanum, or the side next to the labyrinth,
presents an unequal surface.  In its middle is a well marked
rising, the Promontory, (Promontorium,) formed by one end of
the labyrinth.  Just above the superior margin of this promi-
nence, near its centre, is an oval  opening, called, from its shape,
Foramen Ovale, or Fenestra Ovalis;  having its long diameter
horizontal, its superior margin rounded or concave, and its infe-
rior straight.  At the posterior inferior part of the promontory
is another opening, which, though somewhat triangular, is called
the Foramen Rotundum,or Fenestra Rotunda, and in the dried
bone leads to the cochlea, but is naturally stopped by the lining
membrane of the tympanum.   According to  M.  Ribes, this
membranous plug has also two other layers, an internal one, the
continuation  of what lines the cochlea, and a middle one, which
is peculiar.   In these  respects, there  is a correspondence with
the membrana tympani.

  The Eminentia Pyramidalis is a small conical eminence pro-
jecting from the posterior part of the tympanum, on a line with
the fenestra ovalis.   It is  hollow, contains  a muscle, and com-
municates at  the other end with the Canal of Fallopius.  Lower
down, and more externally, there is a small orifice, (Apertura
Chordce,) through which  the nerve called Chorda Tympani
passes.

  The Mastoid Portion  of the  Temporal  bone,  in the adult,
abounds in large  cells or sinuses, which communicate freely

  *  Plate XCVIII. Anat.
  ■\  Ituyschii, Epist. Anat. Probl. viii. Anatomical Museum. 
440
NERVOUS SYSTEM.
with one another.  They are distinct from the diploic structure
of the bone, as they contain no medulla, and are lined  by a
qontinuation of the internal membrane of the tympanum, which
is extremely thin upon them.   The  orifice of communication
between these cells and the  tympanum, is placed  at  the  supe-
rior posterior part of the latter: it is rough and irregular, and
partially occupied by the short leg of the incus.  Just in  front
of this opening, the cavity of the tympanum is extended verti-
cally, for the purpose of accommodating the body of the mal-
leus and of the incus, whereby they are in a great degree con-
cealed, unless the corresponding margin  of the tympanum be
cut away.

  At  the fore part of the tympanum is the Eustachian Tube,
which runs for six or eight lines in the substance of the petrous
bone,  near its exterior margin;  and then  terminates in a carti-
laginous and membranous portion, which communicates  with
the pharynx at the posterior  naris.  The latter extremity of the
Eustachian Tube  is placed on a line with the posterior end of
the inferior spongy bone.   Its orifice is rounded or oval, is large
enough to admit the tip of the little finger, and reposes  against
the side of the internal  pterygoid process of the sphenoid bone.
Though almost within the precincts  of the posterior naris, this
orifice is to be considered as opening into the pharynx.
  This canal, in its whole length, measures nearly two inches,
and, with the exception of the portion in the petrous bone, is
cartilaginous and  membranous.  The cartilage is a single, thick,
triangular plate, flat, and adhering by one of its  edges to the
pterygoid process.  The under part of the tube is membranous,
thin, and affords attachment  to some  of the muscles of the soft
palate.   Its  course is  nearly  horizontal,  backward  and out-
ward.
  It is lined in its whole extent, by a very fine mucous mem-
brane continuous  with that of the pharynx  and of the tympa-
num.   This membrane  is  thickened at its anterior extremity by
the mucous glands beneath it, which assist in giving the marked
elevation to its orifice.  The canal diminishes as it goes back-
ward, so as to receive with difficulty a small probe.

  Parallel with the bony  part of this canal, but above  it, and 
THE TYMPANUM.
441
 separated  by a very thin partition of bone,  is another canal
 which lodges a muscle of the malleus.   On the outer side of
 the  Eustachian tube is the glenoid foramen, by which, in the
 dried bone, the tympanum communicates with the glenoid  ca-
 vity; in  the recent state the foramen receives the long process-
 of the malleus and its  muscle, and transmits the chorda tym-
 pani.

   There are  four bones in the tympanum, which, being suc-
 cessively articulated with each other, form a chain, one end of
 which is fastened  to the membrana tympani, and the other end
 rests upon the foramen ovale.  They are the Malleus; the In-
 cus; the Orbiculare; and the Stapes.

   The Malleus forms the fore part of the chain, and is placed
 almost vertically.   Its superior extremity is the head,  which is
 rounded, with the exception of the posterior face, where a small
 concavo-convex surface is observable, for its articulation with
 the incus.   Its lower extremity is long and tapering, inclines in-
 wardly,  terminates  by a little  knob, and  forms an angle with
 the part  above; this portion is the manubrium, and adheres its
 whole length to the membrana tympani, commencing at the  su-
 perior margin of the latter, and insinuating itself between the
 internal  and the proper layer, as far as the centre of the mem-
 brane. It is this adhesion with the inclination inwards of the ma-
 nubrium, that causes the membrane to be depressed in its centre.
   Between the head and the manubrium is a short portion called
 the neck.  From the superior external extremity of the manu-
 brium there proceeds outwardly the short process, (Processus
 Brevis;)  and from the front of the neck, there proceeds  the long
 and  very delicate process, concave externally and convex  in-
 ternally,  which is insinuated into the  glenoid foramen, and is
the Processus Longus, or Gracilis.

   The Incus is behind the malleus, and is  also upright.  It con-
sists in a body and two branches, which diverge very conside-
rably, and has  a general resemblance  to a molar tooth.   The
body presents, on its fore part, a deep concavity, which articu-
lates with, the convex head of the malleus.  The branch which
arises from the back part of the body is horizontal, looks into 
442
NERVOUS SYSTEM.
the orifice of the mastoid cells, and is much shorter than the
other.  The inferior branch is long, upright, tapering, and near-
ly parallel with the manubrium of  the malleus, but somewhat
within it.

   The Orbiculare is a very small flattened sphere of bone, which
articulates with the lower end of the long process of the incus,
and in adult life is  most generally fused into it, so as to lose its
distinctive character : the latter change sometimes occurs even
in early infancy.

   The Stapes is the last of the chain.  It resembles very strong-
ly the common stirrup iron, from whence its name, and is placed
horizontally at right angles to the incus,  being separated from
the extremity of the long  process of the latter by the os orbicu-
lare, and being directed  inwards to the foramen ovale.  It is
composed of a head, two crura, and a base.
   The head is oblong and flattened: it has a slight depression
where it joins the  orbiculare.   The crura are slightly curved,
with the concavities  towards each other: the anterior is some-
what straighter than the  posterior, and is also shorter.  They
are both excavated, longitudinally, on their concave  surfaces,
and between them is stretched a process of the lining membrane
of the tympanum.  The base is precisely adapted to the fenestra
ovalis, and  is connected  to  it by the  lining membrane of the
tympanum,  but not so  elosely as to prevent it from executing
slight vibratory movements.
   Between the malleus and the incus there is a moveable arti-
culation with a synovial  membrane, but the other joints of the
chain are simply ligamentous.

   This  chain of bones is moved by several muscles, which in-
fluence  the degree of tension of the membrana tympani.

   1. The Laxator Tympani arises  from the posterior end of
the spinous  process of the sphenoid bone, and passing behind
the articulation of the lower jaw into the glenoid foramen, is
inserted, tendinous, along the processus gracilis of the malleus.
   It draws the malleus forwards and outwards, so as to relax
the membrana tympani. 
THE TYMPANUM.
443
  2, The Tensor Tympani is placed in the canal just  above
the Eustachian tube.  It arises from the posterior extremity of
the cartilaginous portion of the latter, and having got into the
tympanum, is changed into a small tendon, which, going out-
wardly, is inserted into the neck  of the malleus, just below its
processus gracilis.
   It draws  the  malleus  inwardly; consequently makes  tense
the membrana tympani, and drives the stapes into the fenestra
ovalis.

   3. The Stapedius arises from the bottom of the cavity in the
pyramid, and  terminates  in a small round tendon, which, going
through  the apex of the latter, is inserted into the head  of the
stapes.
   It draws the stapes backwards, and  perhaps fixes it more
firmly by its contractions.

   4. There is a  fourth  muscle  mentioned by anatomists, the
existence of which is more equivocal; it is called  the Laxator
Tympani Minor.  It is said to arise from the superior margin
of the orifice of the tympanum, and to be inserted into the pro-
cessus brevis of the malleus.  It is by some considered only as
a ligament, to which opinion I am inclined.


         Of the  Lining Membrane of the  Tympanum.

   This membrane is a continuation of the lining membrane of
the pharynx, being introduced into the tympanum through the
Eustachian tube.  It covers completely the surface of the tym-
panum,  and is reflected over its  little bones so as to give them
a covering also; in addition to which, it lines such of the mas-
toid cells as communicate with the tympanum.
   This membrane is  extremely  delicate:  on its surface, adja-
cent to the bones, it is  somewhat fibrous, and  thereby resem-
bles periosteum; but the  other surface has the characters of the
 mucous membranes generally, in the nature of its secretion,
and in  its vascularity, which is very strongly marked in  in-
flammations, and by fine  injections.  Bichat  mentions, that  in
certain catarrhal affections its mucous secretion is so abundant 
444
NERVOUS SYSTEM.
as to fill the whole cavity of the tympanum, and that without
ulceration.   Sometimes, in  such cases, the membrane of the
tympanum  is ruptured, and the discharge finds  its way out
through the meatus externus, presenting itself under a purulent
form, as if  an abscess had formed in the ear.
               SECT. III.--OP THE LABYRINTH.*

  The Labyrinth (Labyrinthus) is placed on the inner side of
the tympanum, in the  thickness of the petrous bone.  Its ex-
terior parietes are bone, but internally there is  a membranous
structure, having, in many respects, the same shape.  It is got
at with great difficulty in the adult, owing to the compactness
of the petrous bone which envelops it; but in the fcetus of the
full period, where it is almost as large as in the adult, the sur-
rounding bone is of a softer and more spongy texture, and may
be pared away with a pen-knife without much trouble.  In the
latter case, the parietes  of the bony labyrinth  remain about
the thickness of  an  egg-shell, and have very much  the  same
degree of consistency  and strength.
  The bony labyrinth consists of three portions: the Vestibulum,
the Semicircular Canals, and the Cochlea.

  The Vestibulum is  the "cavity  to which the foramen  ovale
leads; it, with the  cochlea, occasions the protuberance into
the tympanum, known as the promontory.  It is an irregular
rounded excavation, the  surface of  which is impressed by its
contents;  thus, at the superior posterior and external  part,
next to the semicircular  canals, there  is a superficial Fossa,
called, from its shape, Semi-EIliptica, and at its anterior and
inferior part, nearer the cochlea, another, called  Fossa  Hemi-
Spherica.  These fossas are marked off from each other  by a
ridge of bone, at the lower end of which  there is a third  fossa
between  the  other two, called by Soemmering, Cavitas  sulci-
formis.
  There  are seven orifices belonging to the vestibulum besides
the foramen ovale; five at its posterior part leading into the se-

           * Antonio Scarpa, Disquisit. de Auditu et Olfacto. 
THE LABYRINTH.
445
micircular canals; one anteriorly leading into the upper scala
of the cochlea: and the last placed in its internal paries is the
aqueduct of the vestibule.   In addition to these orifices, the pa-
rietes of this cavity are cribriform in the fossa semi-elliptica
and near the foramen rotundum.*

  The Semicircular Canals (Canales Semicirculares) are at the
posterior extremity of the vestibulum.  They are three in num-
ber, and are named  from  their relative situation, Superior or
Anterior, Posterior or Inferior, and External.   Each one forms
rather more than the half of a semicircle, and has its cavity
about half a line in diameter: their orifices are somewhat di-
lated  beyond this  measurement.  The  apparent thickness of
their parietes is greater in the adult than in the infant.

  The Superior Canal  runs  from without inwards  and  back-
wards.  Its anterior orifice is above  the fenestra ovalis, and is
enlarged into an ampulla or  elliptical cavity.  At its posterior
extremity, it joins the upper  extremity of the inferior canal, so
that a common trunk is thus formed, the orifice of which is at
the internal posterior part of the vestibulum, and is dilated into
 the shape of a funnel.t
  The Posterior or Inferior  Canal  is nearly vertical; has its
concavity in front, and its convexity behind, and joins, as just
remarked, with the superior; its inferior orifice, which is near
the foramen rotundum, is also enlarged into an ampulla or ellip-
tical cavity.  It is the longest of the three canals, and has its
ends nearer together.
  The External Canal is nearly horizontal, and is placed in the
space left by the divergence of the other two.   It is the shortest
and the largest of the three.  Its exterior orifice is also enlarged
into an ampulla or elliptical cavity, and is just behind the fora-
men ovale, or below the ampulla of the upper  canal; the inter-
nal orifice is below the common opening of the other two ca-
 nals.
   It is the union of  the superior and of the posterior canals at
 one of their extremities, which reduces the number of openings

  • Ant. Scarpa, loc. cit.                       t Scarpa, loc. cit
     Vol. II.—39 
446
NERVOUS SYSTEM.
 into the vestibulum, from the semicircular canals, to five instead
 of six.

   The  Cochlea forms the fore part of the labyrinth, and resem-
 bles very strongly the shell of the common snail.  Its base is
 the  bottom of the meatus auditorius  internus, and its apex is
 directed  towards the cavity  of the  tympanum, so  that the
 axis of the cochlea  is  turned downwards and outwards.  It
 consists in a  conoidal tube wound spirally twice and a half
 around a  column of bone termed the Modiolus.  The tube then
 of course diminishes  in size from  the base to the apex of the
 cochlea.

   This conical tube  is  divided in its length  by a plate called
 Lamina Spiralis.   Of the two  compartments  thus formed, one
 is abbve  the other.   The inferior  is the larger, and communi-
 cates at its base,  through the foramen  rotundum, with  the tym-
 panum; it is, therefore, called Scala Tympani. The other com-
 partment communicates  at its base with the vestibulum, and is,
. therefore, called  Scala Vestibuli.
   The  Modiolus  is of a conical  shape, and cribriform: one
 canal, larger  than the others, runs from its base to its summit.
 This canal is  surrounded by many others, which diminish suc-
 cessively  as they advance towards  the apex, and terminate in
 orifices upon  the lamina spiralis.  This  cribriform  arrange-
 ment of the modiolus is the Tractus Spiralis Foraminulosus.
 The base of the modiolus is towards the meatus auditorius in-
 ternus,  and its point does not go to the apex of the  cochlea,
 but stops  short of it, and is expanded into a  cavity called the
 Infundibulum, the base of which is towards  the  apex of the
 cochlea.  That portion of the apex of the cochlea which covers
 over the infundibulum, is the Cupola.
   It was  just  mentioned that the  lamina spiralis divides the
 cochlea into two  tubes; the septum thus formed, does not, how-
 ever, run their whole length, for it  ceases  in the infundibulum
 by a small crooked process of bone, called the Hamulus Coch-
 leas.  The lamina, when examined by strong glasses, is seen
 to consist of  four distinct structures called its Zones.   1. The
 Zona Ossea is next to the modiolus, and is composed of two
 bony laminas,  with an intermediate diploic structure,  in which 
THE LABYRINTH.
447
are the canals for transmitting the filaments of the portio mol-
lis or auditory nerve.  2.  The  Zona Coriacea, on the outer
side of this, the structure of which  is cartilaginous.  3. The
Zona Vesicularis, said to contain in its cells  a  pellucid fluid.
4. The Zona Membranacea, which is probably only the lining
membrane of the cochlea, and completes the lamina spiralis on
its edge next to the periphery of the  cochlea.  Some very re-
spectable anatomists pass over this  minute distinction in the
structure of the septum, and merely  divide it into Zona Ossea,
and into  Zona Mollis.
                Of the Membranous Labyrinth.

   The whole internal face of the bony Labyrinth is lined by
a  very delicate  and vascular membrane, which is more  dis-
tinct  during the early periods of intra  uterine life.  Besides
this, there is a membranous labyrinth, consisting in three, semi-
circular canals,  nearly filling  up  the cavities, and having the
same shape and general arrangement of  the bony canals;  and
in two sacs contained in the vestibule.
   The Semicircular Membranous  Canals  have also at  their
ends the elliptical enlargements  called  ampullae;  they termi-
nate by both extremities in the sac of the superior part of the
vestibule.   This sac is generally called,  from its  shape, Sac-
culus Ellipticus; and by Scarpa, from  its function, the Alveus
Communis.  In  front  of  the  Saceulus Ellipticus, nearer the
cochlea, and opposite the  foramen ovale,  is the Saceulus Sphe-
ricus; it is  a complete  bag, having no communication with the
other, or with the  membranous canals-  Both of the sacs ad-
here to the vestibulum  at their posterior parietes.
   The sacs of the vestibule and the membranous semicircular
canals are filled  with a very fluid transparent liquid.  Accord-
ing to the observations of  M. Ribes, it is  not  necessary to the
function of  hearing that this fluid should  be so abundant as to
distend the membranous labyrinth, inasmuch  as in his dissec-
tions he met with individuals in whom  the latter was only half
filled, and  yet  they had  heard very well.  He also met with
similar cases in which  the fluid was abundant in  the vestibu-
lum, but deficient in the canals, and the reverse.  Correspond- 
448                  NERVOUS SYSTEM.
ing observations have been made  by M. Brugnone, of Turin,*
where he had adopted the precaution of previously freezing the
bone, so that none of the fluid could be  said to have been lost
by accident.  From the frequency with  which this  deficiency
was observed, his opinion seems to be well founded, that  it is
the most natural state of the labyrinth.
  The parietes  of the membranous labyrinth are very thin and
transparent; there is a  very loose  cellular tissue between them
and the bone, and they are susceptible of being highly coloured
by injection.
  A fluid  of the same  character with the  preceding also fills
the scalas of the cochlea, and extends itself into the bony ves-
tibulum and the bony semicircular canals  upon the outer sur-
face of the membranous labyrinth.


                Of ihe Aqueducts of the Ear.

  The Aqueducts (Aquaductus) of Cotunnius, as they are called
after their discoverer, are two small canals which go through
the petrous bone from the labyrinth.  There is one for the ves-
tibule, and another for the cochlea.
  The Aqueduct of the Vestibulum commences in the latter ca-
vity, somewhat in advance of the common orifice  of the two
semicircular canals;  it  goes inwards and opens on the posterior
face of the  petrous bone, behind the meatus  internus.  It en-
larges gradually in its course, which causes it to have somewhat
of a triangular shape, and it  is lined by a  continuation of the
dura mater.  It is about four lines long.
  The Aqueduct of the Cochlea commences in the Scala Tym-
pani, near the foramen  rotundum, and, enlarging in  its  course,
terminates on the under surface of the petrous bone, in the  in-
ternal margin  of the jugular fossa, at  the root of the  little
spine which separates the eighth pair of  nerves from the jugu-
lar vein.
  The anatomistf from whom these canals were  named, and
who first described them, was under an impression that the fluid

  * Mem. de Turin, 1805—1808.
  \ Dominici Cotunnii, Anat. Dissert, de Aquxduct.  Naples, 1761. 
THE ACO.UEDUCTS.
449
of the labyrinth always filled it completely;  and that without a
sort of waste gate for it on  an occasion,  the vibration  of the
stapes would be prevented from  putting it in  motion,  conse-
quently, hearing  must cease.  These canals, the existence of
which is sufficiently obvious  in many subjects, were, therefore,
considered by him as  the desired  avenues for the discharge of
the superabundant fluid, and his  theory and descriptions were
very generally adopted.  Of late years, the investigation  of this
subject has been renewed by MM. Ribes and Brugnone, and their
observations are considered by the French anatomists to have
proved conclusively the  error into which Cotunnius  and  others
have  fallen.
   In  regard to the aqueduct of the vestibule, M. Ribes has found
it only in three instances emptying into the vestibule; for most
commonly it leads, after a course somewhat tortuous, into the
spongy structure of the petrous bone,  at the posterior part of
the vestibule, and smaller canals diverge from it in different di-
rections.   In the cases where it was connected with the laby-
rinth, it was  so by  several orifices  leading into the vestibule,
and into the  posterior semicircular canal.  He  has not found
this canal in the fcetus, nor till some time after birth, and from
his injections he believes that, in  all cases, it and its branches
are only intended to  convey blood  vessels  throughout the pe-
trous bone and to  the labyrinth.
   In  regard to the supposed aqueduct of the cochlea, M. Ribes
has also found it diverging into collateral branches, and occu-
pied by blood vessels, which are distributed to the spongy struc-
ture of the petrous  bone, and to  the tympanum.
   In  my own researches on this  point, on the dried bones, the
canals, as described by Cotunnius, were closed at the labyrinth,
in the case of subjects advanced in life; but, in the middle aged,
and in infantile specimens, I have been  more successful  in
tracing  them fairly into the labyrinth, and have the  prepara-
tions in the  Wistar Museum.  At  the same  time, I think it
much more probable  that they  only  contained blood vessels,
and that Cotunnius was in error.   Besides these vascular ca-
nals,  M. Ribes has described some others having the same use.
                             39* 
450
Nervous system.
      SECT. IV.--OF THE NERVES OF THE ORGAN OF HEARING.

   The Nerves which pass through  the  petrous bone, and are
either wholly or partially spent upon the organ of hearing, come
from three  sources.  1. The Auditory Nerve; 2. The Portio
Dura ; 3. The Trigeminus, or Fifth Pair.
   The Meatus Auditorius Internus conducts  the first two, and
has its bottom divided by a ridge  into two fossas, of which the
upper one is the smaller.   This  bottom,  it has been observed,
corresponds with  the base of the modiolus, and is cribriform.
One foramen, larger than any of the others, and in the superior
fossa, transmits the  portio dura or facial nerve:  all the  others
are occupied by the filaments of  the auditory nerve.

   1. The Auditory Nerve  divides at the bottom of the meatus
into fasciculi of filaments; one of which penetrates into the ves-
tibulum through the  foramina behind that for the portio dura,
and is distributed upon the saceulus ellipticus, and upon the am-
pulla  of the superior and  of the exterior membranous  canal;
other filaments get to the saceulus sphericus; and a third fasci-
culus of filaments is distributed to the ampulla of the posterior
membranous canal.   These several filaments are said to pre-
serve, when they first penetrate into the bony labyrinth, a fibrous
appearance, and are interlaced; they also penetrate the parietes
of the membranous labyrinth, and have their extremities bathed
in its fluid, in which  place they are converted into soft pulp, re-
sembling mucus, or the retina.
   Another very considerable fasciculus of filaments  penetrates
into the canals of  the modiolus, and enters through them into
the cavity of the cochlea, along the  Zona Ossea, and between
its tables; they terminate also by a soft pulp on the internal face
of the lining  membrane of the cochlea.  One of these filaments,
conspicuous for its size, goes through  the central  canal of the
modiolus and terminates in the infundibulum.*

   2. The Facial  Nerve, or Portio Dura, is only connnected to

  * For a knowledge of the minute distribution of  the auditory nerve, the pro-
fession is signally indented to  the  distinguished Scarpa, in his Disquisitiones de
Aiiditu et Olfactu, 
NERVES OF THE ORGAN OF HEARING.            451
the organ of hearing by sending a few filaments to the muscles
of the bones of the tympanum.  The canal of the petrous bone,
through  which it  passes, is  very crooked; beginning at the
larger orifice of the meatus internus in its upper fossa, it passes
outwards until it nearly reaches the Vidian foramen, on the front
of the petrous bone; it then turns-very abruptly backwards, form-
ing an angle, and is continued in a circuit around the superior
and the posterior parietes of the tympanum, till it terminates in
the stylo-mastoid foramen.   Its course is marked by a ridge
projecting into the tympanum, above the foramen ovale, and
passing between the semicircular canals and the cochlea.  This
canal has been very much misnamed by the calling of it the
aqueduct of Fallopius, as its only use is to conduct nerves and
blood vessels.   It is lined by  a  delicate  fibrous membrane, be-
tween which, and its contained parts, there is so little adhesion,
that the  latter may be drawn out entire.
  The facial nerve is joined at the Vidian foramen by the Vi-
dian nerve, shortly after which it sends a filament to the tensor
tympani muscle.*   As it passes the base of the pyramid it de-
taches another filament, which  supplies the stapedius muscle.
  Shortly after this, it  is abandoned by the Vidian nerve, and
does not give off any more branches till it escapes from the sty-
lo-mastoid foramen, when it  sends off a branch, the posterior
auricular (Auricularis  Posterior,) which is distributed by fila-
ments,  some  of which  run  into the mastoid process;  other
branches mount on the side of  this process, to the skin which
covers it, and  to the occipital muscle: others go  to the concha
of the ear, being spent  upon its skin, upon the posterior auricu-
lar  muscle, and some of  them,  penetrating  the pinna, are lost
upon the integuments of the  meatus externus.   The trunk of
the  facial then goes to its destination on the face,

  4. The Chorda Tympani or Superficial  Petrous Nerve, is a
branch of the Pterygoid branch of the Trigeminus, and leaves
it near the anterior part of the  carotid canal of the petrous bone.
It, as just mentioned, under the name of Vidian nerve, joins the
facial nerve at the angle of the canal of Fallopius, and conti-
  * The tensor tympani is also supplied by a nerve from the Third Branch of
the Trigeminus. 
452
NERVOUS SYSTEM.
 nues to adhere closely to it, almost to the styloid foramen ; it
 then abandons the facial nerve at a very acute angle, and run-
 ning upwards and forwards, gets into the cavity of the tympa-
 num, on a level with, but a line or two exterior to the pyramid.
 It then crosses the tympanum nearly horizontally, between the
 long crus of the incus and the handle of the malleus, adhering
 to the latter so as to be affected by its vibrations. At the fore
 part of the tympanum, it anastomoses with some other filaments
 of the fifth pair, by which its size is augmented, but it gives no
 branches to the parts contained in  the tympanum.  It then  is-
 sues from the latter  cavity through the glenoid foramen, and
 descending a short but somewhat variable distance  along the
 ramus of the lower jaw, terminates by anastomosing at an acute
 angle with the lingual branch of the trigeminus.
  To Mr. John Hunter is due the merit  of haying  traced the
 continuity and identity of the Vidian nerve with the  chorda
 tympani.   The continental European  anatomists, for the most
 part, seem ignorant of his observations, and give a very differ-
 ent account of the matter.  Some consider it to arise from the
 facial at its angle, and to anastomose at the other end with the
 pterygoid, or the reverse; and they very generally agree in re-
 garding the chorda tympani as a filament from  the facial, just
 before the latter gets out of the stylo-mastoid foramen.
  The Vidian Nerve, or Superficial Petrous, also traverses the
 tympanum in another place.   Just below the  posterior extre-
 mity of the Eustachian Canal, there is a small foramen, which
 leads upwards to the superior surface  of the  petrous bone, and
 downwards to a small gutter upon the promontory: this gutter
 is converted into a canal  that  opens upon  the under surface of
 the  petrous bone, between the  carotid canal and the jugular
 fossa.  Through the course indicated, passes a  filament from
 the  superficial petrous nerve: this filament is joined by another
 detached from the sympathetic while  in the carotid canal, and
 the  two communicate at the base of the cranium with the gang-
 lion  of the glosso-pharyngeal  nerve.*  These  filaments were
discovered  by Professor Jacobson, of Copenhagen, and form
what is now called the Anastomosis of Jacobson.

 * Meckel, Man. D'Anat. vol. iii. p. 174.  Jacobson,  Supplem. Act. Hafn.
vol. v. p. 292.  An. 1818, 
BOOK  IX.
                       PART IV.


               Special Anatomy of the Nerves.


                     CHAPTER I.


           OF THE NERVES OF THE  ENCEPHALON.


                          SECT. 1.

  The eourse and distribution of the first pair, or the olfactory
nerves, have been described fully in  the account of the brain
and nose.

                 SECT. II.--NERVUS OPTICUS.

  The Optic Nerve, as mentioned in the account of the basis
of the brain, gets into the  orbit by  the optic foramen, and is
there  entirely surrounded by the origins of the muscles of the
eyeball.  It then describes a slight curvature, of which the con-
vexity is outwards, and runs forwards for an inch, when it pe-
netrates into the ball of the eye, where it gives origin to or ex-
pands into  the retina.   Between the muscles and it, except  t
their origins, there is a mass of adipose matter. 
454
NERVOUS SYSTEM.
               SECT. III.--NERVUS MOTOR OCULI.

   The Nervus Motor Oculi, or third pair, having reached from
the basis of the brain to the external side of the cavernous si-
nus, is placed there within and above the optic nerve  and the
sixth pair; it then changes its direction, and penetrates  through
the sphenoidal fissure into the orbit,  on  the outer side of these
nerves, and below them.
   The motor oculi divides, in  the sphenoidal fissure, into two
branches, one above the other.  The first crosses  over the op-
tic nerve and the nasal branch of the ophthalmic, having some
anastomoses with the latter, and  then distributes its filaments
upon the rectus superior muscle; some  of them also penetrate
the latter to get to the levator  palpebras.   The second branch
is much larger than the first.   It passes between the optic nerve
and  the rectus inferior muscle, and is subdivided into  three
fasciculi:  one for the rectus internus muscle; another for the
rectus inferior; and a third, which is  the longest and the small-
est, for the obliquus inferior muscle.   The latter fasciculus, not
far from its root,  gives off a filament, which, going along the
external margin  of the optic nerve, runs into the posterior
margin  of the lenticular or ophthalmic ganglion, and is its short
root.
   The Lenticular Ganglion is situated on  the outer side of the
optic nerve, in  the orbit of the eye,  and is about aiine in dia-
meter, being flattened.  Two  nerves concur to form it: the
branch just alluded to, from the motor oculi, and one from the
ophthalmic  branch of  the  trigeminus.   From this ganglion
arise the most of the ciliary nerves;  which, as stated, are  about
twenty in  number, and go to the choroid coat of the eye and
to the iris.


               SECT. IV.— NERVUS TROCHLEARS.

   The Nervus Trochlearis, or fourth pair, having got  into  its
canal in the cavernous sinus, as it goes along the internal mar-
gin of the ophthalmic  nerve, receives  there a small filament 
NERVUS TRIGEMINUS.
455
from it.*  It then rises a little, and enters the orbit  at the  in-
ternal extremity of the sphenoidal fissure; and, going forwards,
next to the periosteum of the upper part of the orbit, it enters
into the superior  oblique muscle of the eye, near  its middle,
and is distributed upon it.  This nerve  augments in  volume as
it advances  towards its destination.


          SECT. V.--OF THE NERVUS MOTOR EXTERNUS.

  The Nervus Motor Externus, or  sixth pair, having got into
the cavernous sinus, is placed at the external side of the inter-
nal carotid artery, and adheres closely to it.  It there sends off
one or more filaments, which follow the internal carotid artery
through its canal, and anastomose in their descent with a branch
of the pterygoid nerve: the junction of these two forms the up-
per end of the great  sympathetic nerve, and runs down to the
superior cervical ganglion of the sympathetic in two or more
filaments generally.   The sixth nerve enters the orbit  through
the sphenoid fissure, and is  there closely connected with the
nervus  motor oculi  and  the  Nasal nerve.   It penetrates into
the substance of the  rectus externus muscle, and is entirely dis-
tributed upon it;  with the exception that sometimes it sends a
filament to the ophthalmic ganglion.


            SECT. VI.--OF THE NERVUS TRIGEMINUS.

  This  nerve, having formed the ganglion of Gasser, (Plexus
Gangliformis,) on the side of the  petrous bone, then divides,
as mentioned, into three  large trunks, the foremost of which is
the Ophthalmic  Nerve:  the  second fasciculus is the Superior
Maxillary; and the third the  Inferior Maxillary Nerve.
  The Ophthalmic Nerve, or the first branch of  the trigeminus,
is  smaller than  either of the other two branches, and comes
from the  superior part of the plexus gangliformis.   It passes
along the external border of the cavernous sinus, and penetrates
the orbit through the sphenoidal fissure, on  the outer side  of,
and near the motor oculi.
Soemmering', Icones Oculi Humani. 
456                   NERVOUS SYSTEM.
  In its whole course it is united to the trochlearis nerve by
close cellular membrane, and does not give off any ramifications
before  it reaches the orbit, with the exception of the filament
sent to the trochlearis nerve.   While  engaged in the sphenoi-
dal fissure it divides into three branches; the Nasal, the Lachry-
mal, and the  Frontal.
  The Nasal branch  of the ophthalmic, is between the other
two in size.   It ascends obliquely above the optic nerve  to gain
the internal face of the orbit of the eye, and  then  passes  for-
wards  just below the superior oblique muscle, involved in a
quantity of adipose matter.  Shortly after its origin the nasal
nerve detaches a branch (the ramus ciliaris) which, situated at
the external margin of the optic nerve, runs into the ophthalmic
or lenticular ganglion, and constitutes the long  root;  it then
sends off one or more filaments, which, without communicating
with this ganglion, penetrate into the eyeball, and are amongst
the ciliary nerves which have  been described.
  The nasal  nerve, continuing to pass  forward along the inter-
nal paries of  the orbit, when it reaches the anterior internal or-
bitary  foramen, detaches  through  it the internal nasal  or  eth-
moidal branch, which, thus  getting into the cavity of the  cra-
nium, goes along side  of  the crista galli, and  then passes  into
the nose through the  formost  hole of the cribriform plate.   It
then descends along the anterior  part  of the nose, on the outer
side of the Schneiderian membrane,  and is  spent  by  ramifi-
cations upon the contiguous portions  of the  latter.  Some  of
its  terminating  branches  reach  the tip  of  the  nose  and  the
alas.*
   The nasal nerve, after this branch is sent off, is frequent-
ly called external nasal,  or nervus infra-trochlearis.   It con-
tinues  to advance along  the  under margin of the  trochlearis
muscle and  gets to the trochlea, near which it divides  into
an  upper and an under ramuscle;  from them filaments  proceed
to the upper and under eyelids, to the lachrymal sac, the lachry-
mal caruncle, the tunica  conjunctiva,  and the muscles on the
root of the nose.   These filaments anastomose  with   the ter-
minating branches of  the  frontal nerve, the facia!, and the in-
* See Nerves of Nose. 
NERVUS TRIGEMINUS.                  457
fra-orbitary.   According to Dr. G. Transmondi,* of Rome, two
filaments may be traced very distinctly from the external  na-
sal nerve to the tensor tarsi muscle of the lachrymal sac.   They
adhere to the muscle  by means of cellular structure, and pass
on to its  bifurcated extremities and to the puncta lachryma-
lia.

   The Frontal Nerve is the  largest of the three branches of
the ophthalmic.  It proceeds forward between the levator pal-
pebras superioris  and the contiguous part of the orbit, and in
this  course is  divided into two branches, the internal and the
external frontal nerve.   The former approaches the trochlea
of the upper oblique muscle, and detaches a  filament to join
with one from the Nasal nerve.  Other filaments are detached
to the upper eyelid, some of  which anastomose with filaments
from the Lachrymal nerve.  The internal branch of the frontal
then issues from the orbit just by the trochlea, and, in ascend-
ing, is lost upon  the  occipito-frontalis, the corrugator  super-
cilii, and the  orbicularis  muscle.  The externa] branch  of the
fro/.tal issues  from the orbit',  through the  supra-orbitary fora-
men.  It quickly detaches a filament, which goes outwardly to
anastomose with the  facial; the remaining part of the  nerve is
distributed to the occipito-frontalis, to the corrugator supercilii,
to the integuments of the forehead, and to the scalp.  This dis-
tribution, according to Bichat, is  best followed by detaching the
skin, muscles, and  periosteum from the cranium, from behind
forwards as far as the orbit.

   The Lachrymal Branch  of the ophthalmic  nerve goes  for-
wards along the  external side of the orbit near the superior
margin of the rectus externus muscle.   In this course it sends
off a filament through the spheno-maxillary fissure which unites
with one from the second branch of the fifth pair; it afterwards
sends off another filament, which,  passing through a foramen
in the malar  bone, anastomoses  with a  filament of the facial
nerve.   What remains of the lachrymal nerve is  then distri-

   * Intorno la scoperta cli due nervi del Occhio umano ragguaglio del Dr. Giu-
seppe Trasmondi, Professore di Anatomia Practica nel ven. ospidale della Con-
solazione.  Roma, 1823.
   Vol. II.—40 
458                   NERVOUS SYSTEM.
buted by several filaments upon the lachrymal gland, the upper
eyelid, and some of them reach the conjunctiva.


             Second Branch of the Trigeminus.

  The Second  Branch of the Fifth Pair, (Nervus Maxillaris
Superior,) arising from the middle of the plexus gangliformis,
or ganglion of Gasser,  and also,  in part, from the common
trunk formed from the anterior and posterior roots of the tri-
geminus, gets from the  cranium through  the foramen  rotun-
dum of the sphenoid bone.   While still in the  cranium  it
sometimes forms  an anastomosis,  described by  Laumonier,
with the  beginning of the sympathetic nerve, but generally it
does not detach any filament tili it reaches  the pterygo-max-
illary fossa.
  At a short distance after  its exit from the cranium, it gives
off a small filament, the  Nervus Subcutaneus Malas, which as-
cends into the orbit through the  spheno-maxillary fissure, and
then divides.  One of the branches, the malar, anastomoses
with the lachrymal nerve, and leaves filaments with the lachry-
mal gland; it then gets, by one or more filaments,  through the
holes of the malar bone to the face, and terminates on the or-
bicularis  mu,scle and the skin of the cheek, anastomosing with
the  extremities of the facial nerve.  The other  branch, the
temporal, gets  into the  temporal fossa  by penetrating the
internal part of the malar  bone,  and,  having anastomosed
with a branch of the inferior maxillary  nerve,  it  goes out-
wards and backwards, becomes  superficial by penetrating the
temporal aponeurosis, and  terminates on  the integuments  of
the  temple, anastomosing there with the  branches  of the  facial
nerve.
  The superior maxillary then divides  into  two trunks  much
larger than the  preceding, and of a volume  nearly equal; the
Infra-Orbital and the Pterygo-Palatine.
  The Infra-Orbital (Nervus Infra-Orbitalis) passes forwards,
with a slight ascent, to the posterior part of the orbit, and en-
ters  the infra-orbitar canal.  As it is about engaging  in the
latter, it  detaches  a considerable  branch, the Posterior Den- 
NERVUS TRIGEMINUS.
459
tal.  This branch  descends a little distance, externally, along
the posterior paries of the maxillary sinus, then penetrates into
the cavity of the latter.   It  terminates by filaments, some of
which supply the lining membrane of the antrum;  others pass
through the  little canals  leading to the three large grinders,
and enter the roots of the latter;  others go to  the  correspond-
ing gums.  One branch goes along the outer side  of the sinus
to anastomose with the anterior  dental nerve.   The'posterior
dental, before it enters the  bone, also  detaches a branch of
some size, which winds around the tuberosity of the maxillary
bone, and is spent upon the  buccinator muscle  and upon the
gums.
   The infra-orbitary nerve afterwards, in its course through
the canal, sends off the  anterior dental  nerves from one or
more roots.  Some of them detach fibres to the  mucous mem-
brane of the nose,  where it covers the anterior part of the in-
ferior turbinated bone.  With this exception, they are distri-
buted, through their appropriate  canals in the bone, to the in-
cisor and canine teeth, and to the  corresponding gums.   The
small molar teeth  are  most  frequently supplied  by a union of
filaments, from the anterior and posterior  dental nerves.
   The infra-orbitar nerve, on issuing  from the infra-orbitar fo-
ramen, is most  frequently found  already  divided  into several
fasciculi, which may be classed into superior and into inferior.
The former, called Palpebral, radiate, externally and internal-
ly, into filaments which supply the lower eyelid.   One of these
filaments may be traced to the end of the nose,  where it anas-
tomoses with the internal nasal branch of the ophthalmic; ano-
ther, which terminates about  the  internal  angle  of the eye,
anastomoses there with  the  external nasal  nerve.   Others of
its terminating  filaments  anastomose with  the  extremities of
the facial nerve on the eyelid.  The inferior fasciculi are more
numerous and large than the superior.  They descend upon
the face  covered by the  levator  muscles  of the  upper lip, and
from their  distribution are called Labial.   The most internal
of these fasciculi  terminate  on the skin, the muscles, and the
beo-inning of the mucous membrane  of the nose, where they
anastomose with the extremities of  the internal nasal  nerve.
The middle fasciculi go to the muscles of  the upper lip and the
skin of the latter, and  to its mucous glands.   The external fas- 
460
NERVOUS SYSTEM.
ciculi go to the zygomatic muscles and to the contiguous skin.
All the foregoing branches of the  infra-orbitar nerve anasto-
mose with the extremities  of the facial, and are so minutely
distributed  to  the skin and muscles of the face, that it would
require  a very protracted description  to point them out par-
ticularly.

  The Pterygo-palatine Nerve  (Nervus Pterygo-palatinus) de-
scends, as a single or a double  trunk, from its root to the out-
side  of the spheno-palatine foramen, and there forms the gang-
lion of Meckel,* or the spheno-palatine ganglion, the existence
of which is not constant.  From this ganglion, or from the nerve
itself proceed several branches.                     "*
  A  filament, described by Bock, is detached from it, which en-
ters into the sphenoidal sinus to be distributed on its lining mem-
brane, and sometimes to  anastomose with the motor externus
oculi.
  Then  arise  the Spheno-palatine branches, which  enter the
nose through the spheno-palatine foramen, and are distributed
upon the mucous membrane  of its septum and turbinated por-
tions, after the manner described in the account of the nose,

  The Vidian or Pterygoid Nerve (Nervus Vidianus, recurrens,
pterygojdeus) arises from the  inferior part of the  ganglion, and
is a recurrent branch, which goes backwards through the ptery-
goid foramen of the  sphenoid bone.  From it there arise some
filaments, which get  to the mucous membrane about the ante-
rior  orifice of the Eustachian  Tube, either through the spheno-
palatine foramen, or by small  foramina in the pterygoid process
of the sphenoid bone.  They  are sometimes united into a single
trunk, called pharyngeal, by  Bock.  The Vidian nerve, while
still in its canal, then divides into  two trunks, the superficial,
and the deep petrous.

  The Superficial Petrous  (Nervus Petrosus Superficialis) tra-
verses the cartilaginous matter at the point of the petrous bone,
in the anterior foramen lacerum of the basis of the cranium,
gets  there into the cavity of  the latter,  continues its progress
* Discovered by Meckel, 1749, 
NERVUS TRIGEMINUS.
461
backwards on the superior face of the petrous bone, in a gutter
marked on the bone, and disappears through the Vidian fora-
men.   It, in a short space, reaches the aqueduct of Fallopius,
and then continues to adhere to the facial nerve till the latter
almost reaches the stylo-mastoid foramen: it  then  abandons
the facial nerve, and, as  mentioned in the account of the ear,
traverses the tympanum under the name of chorda tympani;
and, finally, emerging at the glenoid  foramen,  it runs to asso-
ciate itself with the lingual branch of the trigeminus.  The su-
perficial  petrous, in the early part of its course, at  the point of
the petrous bone, detaches one or more filaments to the  sym-
pathetic  in the carotid canal.

   The Deep  Petrous  (Nervus Pelrosus Profundus) is  larger
than the  other.   It also penetrates through the cartilaginous
matter at the point of the petrous bone, and enters  the cavity
of the  cranium under the dura mater.  It then advances to the
internal  carotid artery, and anastomoses there  with a filament
from the motor externus or  sixth nerve.  This anastomosis  is
commonly called the beginning of the sympathetic nerve.

   The Palatine Nerve  (Nervus Palatinus) proceeds from the
inferior  part of the  ganglion of Meckel, and gets  to the soft
palate of the mouth through the posterior palatine foramen.  In
this  course, it  detaches  several filaments to the Schneiderian
membrane, which reach it either through the  spheno-palatine
foramen, or by perforating the nasal lamella of the  palate bone.
These are described in the account of the nose.

   The trunk of the  palatine nerve, having reached the roof of
the mouth, bends forwards,  and is divided into  many filaments,
some of which are distributed along the gums of the upper jaw,
others  are distributed on the lining membrane  of the hard pa-
late and upon its mucous glands.
   There are two other nerves, which arise either immediately
from the palatine, or from the  ganglion of Meckel, and  go  to
supply the soft palate.   They are called the smaller palatine.
One of them, having proceeded for a short distance in the pos-
terior palatine canal, departs from it  in a little canal of its own,
which opens behind  the hook of the internal pterygoid process,
                            40* 
462
NERVOUS SYSTEM.
It  then  radiates into filaments, which supply the  tonsil  gland
and the  muscular and membranous structure of the soft palate.
The other smaller palatine also traverses, after the same man-
ner, its own canal, and is likewise distributed to the tonsil gland
and to the soft palate.


               Third Branch of the Trigeminus.

   The  Third  Branch of the Trigeminus (Nervus Inframaxil-
laris) is the largest  of the three.  It arises from  the posterior
inferior part of the ganglion  of Gasser, and having anastomosed
with the cavernous  ganglion  of the  sympathetic nerve by fila-
ments,  which are not constant,  it emerges  from the cranium
through the foramen ovale  of the sphenoid bone.  A portion
of this  branch, as mentioned, does not enter into the composi-
tion of  the ganglion of  Gasser, but proceeds immediately from
the pons varolii.
   The  inferior maxillary nerve, at its exit  from the foramen
ovale, is covered  by the plerygoideus  externus muscle, and
commonly divides there into two branches, one anterior and the
other posterior or else sends off two sets of branches—the first
for the  muscles of mastication—and the second set for the low-
er jaw  arid tongue.
   The  Anterior Branch, or  set, which is much smaller than the
other, radiates into five fasciculi; the masseter nerve;  the two
temporal;  the buccal; and the pterygoid.
   a. The  Masseter Nerve   is  directed  horizontally  outwards
 and backwards, along the external margin of the pterygoideus
 externus, and  in front  of the temporo-maxillary articulation:
 it leaves, some  filaments with the latter, and  then passing be-
 tween  the insertion of the temporal  and of  the external ptery-
 goid muscle, over  the concave edge of the bone, between the
 condyle and the coronoid process of the lower jaw, it penetrates
 into the  substance of the masseter muscle,  and  is distributed
 through it.
   b. The two Temporal branches arise  by a common fascicu-
 lus, but sometimes differently.  They pass  outwards, horizon-
 tally,  between the external pterygoid muscle and  zygomatic
 fossa.   They then  ascend on the side of the temporal bone, be- 
NErvus Trigeminus.
463
tween it and the temporal muscle, and are distributed through
the latter by a great number of filaments.  Some of these fila-
ments penetrate the aponeurosis, to anastomose with the super-
ficial temporal  nerves.  And one  of them anastomoses With
the Temporal Branch of the Subcutaneus Malas, in the tempo-
ral fossa.
   c. The Buccal Branch is the largest of the five.  It advances
between the pterygoid muscles, to which it furnishes a few fila-
ments, and then descends between the temporal and external
pterygoid muscle to the posterior part of the buccinator.  It is
principally distributed on the latter,  upon the buccal glands,
and the corresponding part  of  the  lining membrane  of  the
mouth.  Some of its branches advance under the integuments
of the face, as far as the commissure of the lips to the muscles
there, and anastomose with the facial nerve.
   d. The  Pterygoid Branch is  the smallest, and is distributed
 principally on the internal  pterygoid muscle.

   The Posterior Branch of the inferior maxillary nerve is so
 large, that it looks like a continuation of the trunk.  It.is di-
 vided into the superficial  temporal, the inferior dental, and the
 lingual nerve.
    a. The  Superficial Temporal Branch is formed by a union
 of two fasciculi, between which passes the middle artery of the
 dura mater; the inferior of these fasciculi comes from the  infe-
 rior dental nerve.   The nerve is directed outwards, and winds
 horizontally around the posterior face of the neck of the  con-
 dyle  of the lower jaw, between it and the meatus auditorius
 externus.  It is there divided into several small fasciculi, two
 or three of which penetrate into the substance of the parotid
 gland, and anastomose with the facial nerve or its ramifications;
 one or two others go backwards, penetrate  between the bony
 and the  cartilaginous meatus to the auditory canal, and are
 dispersed by fine filaments upon the concha, and the meatus ex-
 ternus.  According to Bock, one of these filaments supplies the
 membrane of the tympanum,  and  also anastomoses with the
 chorda tympani.  Another branch of the superficial temporal,
  which is  the  largest of  any, traverses  the parotid gland, and
  thereby becomes  superficial, just in front of the external ear.
  It then divides  into filaments, which follow the  course of the 
464
NERVOUS SYSTEM.
superficial temporal artery, and thereby supply the middle part
of the  integuments on the  side of the head.   It anastomoses
with the filaments of the frontal  nerve, and with those of the
occipital.
  b. The  Inferior Dental Nerve  is  placed between the other
two branches, and exceeds  them  in size.   It descends between
the two pterygoid muscles,  towards the posterior mental fora-
men.   Just above the latter it detaches  a  small  branch, the
mylo-hyoid, which occupies the small gutter on the bone lead-
ing downward from the posterior  mental foramen.  This branch
sends a filament to the submaxillary gland, then passes between
the anterior belly of  the  digastric muscle and the mylo-hyoi-
deus, to both of which it gives filaments, and  finally winding
over the base of the lower jaw in front, it is lost upon the mus-
cles of the chin.
  The inferior dental nerve then enters  the posterior mental
foramen,  and  divides into  two  branches, which  run parallel
with one another through the canal in the middle of the spongy
structure  of the bone, and send a great number of anastomotic
filaments to each other.  One of the branches,  the dental, pro-
perly speaking, as it passes along the ends of the roots of the
teeth, detaches a filament to each root, from the last grinder to
the first incisor tooth inclusively: it also sends a filament to the
gum intermediate  to every two  teeth.  All of these filaments
arise from the dental nerve, at places behind the points of des-
tination;  so that they have before  reaching the latter, to run
forwards  and upwards through   little  canals  in  the cellular
structure of the bone.
  The other branch of the  inferior dental nerve is the mental;
it does not  advance so far forward in the  bone as the pre-
ceding, but issues from it at the  anterior  mental foramen, and
immediately is divided into two fasciculi, the inferior  labial
nerves.  The internal fasciculus is distributed by filaments upon
the muscles of the chin and lower lip, the  contiguous  linino-
membrane of the mouth and the labial glands.  The external
fasciculus rises upwards and  is  distributed  on the  muscular
structure, about the under part of the commissure of the lip, and
to the contiguous lining membrane and glands of the mouth.
  c. The  Lingual Nerve descends  in company with the infe-
rior dental, but in advance  of it, and  diverging slightly.  While 
NERVUS FACIALIS.
465
between the two pterygoid muscles it receives the chorda tym-
pani at a very acute angle.  It then passes towards the side of
the root of the tongue, deeply concealed  by the angle of the
lower jaw, and above the submaxillary gland, to which it gives
some considerable filaments.  Occasionally, however,  a gan-
glion, called the maxillary, is formed here by one or more fila-
ments  of  the  lingual nerve, and from this  ganglion proceed
filaments to-the submaxillary gland.
  The lingual nerve then proceeds forwards between the my-
lo-hyoideus and the hyo-glossus muscle, and  between the sub-
lingual gland and the latter, having in front of it the excretory
duct of the submaxillary gland.  It  anastomoses frequently
with the hypoglossal nerve, sends several filaments to the lining
membrane of the mouth, below the tongue, and to the sublin-
gual gland.   It  then  divides, or radiates,  into seven or  eight
fasciculi, which run upwards and forwards on the side of the
stylo-glossus muscle, and the genio-hyo-glossus, and are finally
spent by very fine filaments penetrating  into the structure of
the papillas, on the upper surface of the tongue.
  The third branch of the trigeminus, according to Dr. Arnold,
forms, by  several filaments, a ganglion near  the foramen ovale.
This ganglion is below the  spinous process of the sphenoid
bone, and sends off several filaments: one  contributes  to the
nervous anastomosis of Jacobson,*  which connects the ptery-
goid, sympathetic, and glosso-pharyngeal nerves: another fila-
ment passes to the tensor tympani,  and  is distributed upon it.
Other filaments join the superficial temporal  nerve: that part of
it which supplies the  membrana  tympani.  There is also aq
anastomosis with the portio mollis.t


                 SECT. VII.--NERVUS FACIALIS.

  The Facial Nerve (Nervus Facialis; portio dura septimi; par
septimum) having gained the meatus auditorius internus, passes
in front of the auditory nerve into the canal  of Fallopius, and
winding through it, around the tympanum,  it emerges at the

  * This nervous anastomosis is described, page 452, article Vidian Nerve,
  | Am. Med. Jour, vol, v. p, 192, 
466                    NERVOUS SYSTEM.
stylo-mastoid foramen, having sent in this course one or more
filaments to the muscles of the  little bones of the tympanum.
  Afterwards, the facial nerve gives off several branches, which
are distributed as follows:—
  a. The Posterior Auricular (Auricularis  Posterior) arises
near the  stylo-mastoid foramen, as stated in the account of the
Nerves of the Ear; and having sent several  filaments into  the
mastoid process, it winds over  the anterior face of the base of
the latter, and divides into two fasciculi.  The anterior is dis-
tributed in filaments upon the back of the external ear, the car-
tilaginous meatus, and the posterior auris muscle; the posterior
ascends upon the mastoid portion of the temporal bone to the
posterior belly of the occipito-frontalis muscle, and is spent by
filaments to the latter, and  to  the  corresponding integuments,
anastomosing likewise  with  ramifications  of  the  occipital
nerve.
  b. The facial nerve then detaches filaments to the muscles
of the styloid process, and to the posterior  belly of the digas-
tric muscle.   It also sends filaments of anastomosis to the su-
perior part of the sympathetic nerve; to the cutaneous cervical;
and to ramifications of the  glosso-pharyngeal, of the pneumo-
gastric, and of the accessory.
  The facial  nerve, having given  off the foregoing  filaments
and  branches, penetrates downwards and  forwards into  the
substance of the parotid gland, where it is divided into a num-
ber of branches, varying from two  to five, which form a plexus
by their anastomosis.  This plexus is re-enforced, as mentioned,
by branches from the  superficial temporal of the inferior max-
illary, which  wind around the  neck of  the lower  jaw.  It is
then distributed to the side of the face in radiating clusters or
columns of filaments, called the temporo-facial, the buccal, and
the cervico-facial.
  The Temporo-Facial  Nerves, or Branches, are hid, for some
distance, in the upper part of the parotid  gland, which they
traverse below the neck of the lower jaw.  They divide into
filaments, some of which go to  the temple, and others to the
cheek.  The  temporal branches are commonly two or three in
number;  they leave filaments  with the parotid gland, mount
over  the zygoma, and  are distributed to  the anterior auris
muscle, to the  outer  section of the orbicularis palpebrarum, 
NERVUS FACIALIS.
467
and to the integuments of the temple; they anastomose in their
distribution  with each other, with the superficial  and deep
temporal branches  of the  inferior maxillary nerve, and with
the frontal and lachrymal branches of the ophthalmic.   The
malar branches are primitively, also, two or three in number:
they cross the malar bone, dividing, subdividing, and anasto-
mosing again, and are spent upon the integuments and muscles
of this part of the face.   They also anastomose with filaments
of the lachrymal nerve,  and with those  of the  infra-orbitar
nerve.
   The Buccal Branches  are three in number, sometimes two
only; and pass across the masseter muscle  under the  skin.  The
superior anastomoses with  the temporo-facial,  and the inferior
with the cervico-facial.  The buccal branches supply the skin
and muscles of the face intermediate to the eye and to the low-
er lip.  The  numerous filaments into which they divide anas-
tomose  frequently with each other, and with the branches of
the fifth pair, which appear about the same parts, as the exter-
nal and internal  nasal nerve, the infra-orbitar, and so on.   The
middle buccal is parallel  with the duct of the parotid gland, and
adheres to it.
   The Cervico-Facial Branch descends in  the substance of the
parotid gland, behind  the  ramus of the lower jaw;  when it
reaches the  angle of the  latter it goes  obliquely  forwards, be-
neath the platysma myodes muscle.  Though it sends off many
fasciculi, they may  be referred to two divisions, a superior and
an inferior.   The first crosses the inferior  part of the masseter
muscle, and may be traced in its numerous distribution of fila-
ments, to the integuments and muscles lying upon the body of
the lower jaw.   These filaments anastomose with each other,
and with the mental branches of  the inferior dental nerve.  The
inferior division supplies the skin  and the platysma myodes mus-
cle on the upper part of  the neck  along the base of the lower
jaw.   Its filaments  are joined by several coming from the an-
terior fasciculus of the third cervical nerve.
   The  anastomoses of the facial nerve, derived  from its own
branches and from those of the trigeminus, which  reach the
face, are entirely too numerous for a detailed  description of
them; it, indeed, appears unnecessary to extend the latter be- 
468                   NERVOUS SYSTEM.
yond  a certain point.  The most  satisfactory account  has
been published by Meckel.*


              SECT. VIII.--NERVUS HYPOGLOSSUS.

  The Hypoglossal  Nerve, (Nervus  Hypoglossus, Lingualis,)
having arisen from the medulla oblongata, and escaped from
the cranium through the  anterior condyloid foramen, adheres
closely for an inch to  the  pneumogastric nerve.  It descends
between the external carotid artery and the internal jugular
vein, the latter  being behind the other;  and then winds over
the carotid, externally, just below the  origin of the occipital ar-
tery.  It is there covered by the posterior belly of the  digas-
tricus and  by the stylo-hyoideus.  It  then passes forwards be-
neath the external jugular vein, and lower down  somewhat than
the tendon of the digastric muscle, and, finally, ascends  to the
tongue, being covered or  concealed by the mylo-hyoideus mus-
cle.  The nerve in this course, from the external carotid  to the
tongue,  forms a remarkable curve, the convexity of which is
downwards.
  The Hypoglossal, while adhering to the pneumo-gastric, com-
monly leaves a few  filaments with it.  As it crosses the ex-
ternal carotid, it detaches a large branch, the Ramus Descen-
dens Noni, which goes down  the neck, along  the sheath of
the carotid artery and the internal jugular vein, in front  of the
latter.
  The ramus descendens has been beautifully figured by Scar-
pa, in his  Plates  of  the Nerves.  According to him, when  it
has got about half way down the neck, but still  resting  on the
sheath of the vessels, it detaches, in front,  two filaments, which,
after the course of an inch forwards,  unite, and then separate
again to be distributed to the upper ends of the omo-hyoid  and
sterno-hyoid  muscles.  The descendens  noni  then forms, an
inch lower down, a small gangliform  plexus, resting upon the
sheath of the great vessels of the neck,  under  the  omo-hyoid
muscle.   This plexus is joined by two fasciculi,  which descend
from the first  and second cervical nerves, and from it pro-

  * J. F. Meckel, de Nervis Faciei, Mem. de l'Acad. des S. de Berlin, 1751, Cal.
dani, Tab. 247. 
NERVUS ACCESS0R1US.
469
ceed downwards and backwards, two filaments, which join the
phrenic nerve; also, one  to the lower part of the  omo-hyoid
muscle; and three  or more, which are divided and distributed
upon the sterno-hyoid and thyroid muscles, and upon the mus-
cles  of the larynx.   Meckel states, that some of these ramifica-
tions, on the left side principally, penetrate to the thorax, and
reach the pericardium.
  The hypoglossal  nerve, having sent off the ramus descend-
ens,  reaches the external face of the hyo-glossus muscle, and is
there concealed by the mylo-hyoideus, where it gives filaments
to the muscles of the larynx, to  the hyo-glossus, genio-hyoideus,
and  genio-hyo-glossus.  These  filaments anastomose frequently
with e<ach other, and in two or  three places at the anterior part
of the tongue with  the lingual branch of the nervus trigeminus.
After these branches are given off, the trunk of the hypo-glossal
nerve penetrates  into the substance  of the  genio-hyo-glossus
muscle, and extends itself near  its fellow, and not far from  the
middle line of the tongue to the point of the latter.   It first dis-
tributes filaments  near the posterior  part  of the  tongue, and
then, successively, as far as its  anterior  extremity.  They can-
not  be traced  to the papillas, but are lost upon the muscular
structure.
   It is a general opinion among anatomists that the hypo-glos-
sal nerve is only intended to excite the muscular  movements
of the tongue.  The opinion  is founded  upon the  circumstance
of its filaments not reaohing the papillas, whereas those of the
lingual branch of the trigeminus do.   Colombo narrates a case,
in which there was a congenital  privation of taste, where  the
lingual branch of the trigeminus was distributed upon the occi-
put instead of upon the tongue,  which goes far to prove the dif-
ference of function in the two nerves.


               SECT. IX.--NERVUS ACCESSORIUS.

  The Accessory Nerve, (Nervus Accessorius, Willisii,) having
arisen, as described from the cervical medulla and the medulla
oblongata, is directed, outwards to the posterior foramen lace-
rum, in company with the pneumogastric or par vagum.   Some-
times it is separated from  it in  its passage through  the base of
  Vol. II.—41 
470                   NERVOUS SYSTEM.

the cranium, by  a thin partition of dura mater; on other occa-
sions merely by  a fold of the tunica arachnoidea: but at the in-
ferior part of this  foramen it adheres so closely to the par va-
sium that the two look like but one nerve.

   Near its exit it is divided into two fasciculi.   The  internal
gives off one or two  filaments, which, joining a branch of the
par vagum, forms the superior  pharyngeal nerve; the internal
branch then descends, and being-divided into several branches,
they, successively, join the upper part of the par vagum.  The
external fasciculus  descends for two inches behind the internal
jugular vein, being placed first of all between it  and  the occipi-
tal artery, but  subsequently between the vein and the sterno-
mastoid muscle.  It then pierces this muscle about one-third of
the length of the latter from its superior extremity, and  leaves
filaments in it which  anastomose with some from the third cer-
vical nerve.  In continuing its  descent, it is  re-enforced  and
augmented considerably in volume, by branches from  the second
and  third  cervical.   Having reached the anterior margin of the
trapezius muscle, it then distributes itself to the latter, by inter-
nal and by external branches.


            SECT. X.--XERVUS GLOSSO-PHARYNGEUS.

   The Glosso-Pharyngeal  Nerve (Nei-vus Glosso-Pharyngeus,)
though commonly considered as  distinct from the pneumogas-
tric, has so many connexions with  it,  both at  its root, in its
course through  the posterior foramen lacerum, and in  its dis-
tribution, that it seems like a part or branch of the  same.   At
the base of the cranium in front of the pneumogastric, it forms,
according  to some  anatomists,*  a ganglion of five or six lines
in length, the existence of which  was denied by Bichat.   From
this ganglion proceeds a  filament,-(- which penetrates  into the
tympanum  and divides into two branches; one of them ascends
along the promontory, having detached  a filament to the mem-
brane of the foramen  rotundum: it then penetrates the petrous

  * Andersach and lluber.  This ganglion is considered by some as commencing
before the nerve penetrates the foramen lacerum.
  f Rosenmuller, Jacobson, Lobstein. 
NERVUS GLOSSO-PHARYNGEUS.              471
bone; and  anastomoses or joins  with the  superficial petrous
nerve.  The  other branch  passes below  the bony Eustachian
Tube, and, gaining the  carotid canal, anastomoses there with
the Sympathetic Nerve.   This is part of the anastomosis of Ja-
cobson, and is also  described  in the account  of the  Vidian
Nerve.*  The ganglion  also gives off  other filaments, which
join the pneumogastric nerve, the  accessory and the sympathe-
tic.
   On issuing from the posterior foramen lacerum, the  glosso-
pharyngeal is separated  from the pneumogastric by the internal
jugular vein.   It is then directed downwards and forwards be-
tween the internal carotid and the  stylo-pharyngeus muscle,
afterwards between the latter and  the  stylo-glossus;  it fol-
lows  the direction of the latter to the side of the root of the
tongue.
   In  this course,  it sends off  many filaments.  Shortly  after
leaving the cranium, it detaches one backwards to the digastric
branch of the facial, and another to the pneumogastric.  It then
sends  off two filaments, which  descend along the internal and
common carotid, and are divided into several branches, some
of which anastomose with the  pharyngeal branch of  the pneu-
mogastric, others descend on the common carotid with filaments
from  the pharyngeal branch, and being joined by two or three
small twigs from the superior cervical ganglion, they  reach the
lower part of the neck, and concur in the forming of the super-
ficial cardiac  nerve.  Farther down after the origin of these
branches the glosso-pharyngeal detaches two or three filaments
to the stylo-pharyngeus  muscle, as well as some to the upper and
middle constrictors of the pharynx, to the pharyngeal plexus of
the sympathetic and pneumogastric, and to the posterior lateral
and superficial part of the tongue.
   The glosso-pharyngeal nerve having got between  the  stylo
and hyo-glossus muscles, is placed intermediately to the lingual
branch of the  fifth pair and hypo-glossal nerve.  Some of its
branches then go to the integuments of the base of the  tongue,
to its mucous glands, large papillas, and may be traced  to the
mucous membrane of the soft palate, to the amygdalas, and to
the covering membrane of the epiglottis.  Olhers go into the
* See Nerves of Org: n of Hearing. 
472
NERVOUS SYSTEM.
muscles of the tongue, and others may be traced along the ex-
ternal margin of the tongue, beneath its  mucous membrane for
some distance.   Scarpa  has delineated a  remarkable plexus,
which he denominates Circulus Tonsillaris Anderschii or Anas-
tomosis Plexuosa, formed  by these  several filaments  and by
branches of the lingual, on the side of the root of the tongue,
at the base of the tonsil gland.

             SECT. XI.—NERVUS PNEUMOGASTRICUS.

  The Pneumogastric Nerve (Arervus Pneumogastricus, Vagus,
Par Octavum, Decimum of Andersach,) at its exit from the cra-
nium through the posterior foramen lacerum, in front of the in-
ternal jugular vein, is closely united to the hypo-glossal, glosso-
pharyngeal, and accessory nerves, by compact cellular substance.
It is first placed in front of the hypo-glossal nerve, but, in a short
space, gets behind it, and is also separated from the glosso-pha-
ryngeal by the  internal jugular vein.  Opposite the  transverse
process of the atlas,  it leaves  the hypo-glossal nerve, and as-
sumes a position between the internal carotid  and the internal
jugular, on the vertebral  side of these vessels,  and is enveloped
in their sheath of dense  cellular substance.  It maintains this
relative position  along the common carotid to the root of the
neck.
  At the latter place, the pneumogastric of the right side goes
in front of the subclavian artery, Hear its root, but on the left
side it crosses the root of the left subclavian artery, and the arch
of the aorta  to  the left  of the origin of the  left carotid.   In
getting fairly into the cavity of the thorax, it is directed  back-
wards and downwards from these points towards  the posterior
face of the bronchus, between it and the pleura.   It then  aban-
dons the bronchus, and applies itself  to the oesophagus, and fol-
lows it through the diaphragm to the stomach.  The nerve  of
the  left side, in its course along the oesophagus, is on the front
surface of the latter, and the nerve of the right side, on its pos-
terior surface.
  The pneumogastric anastomoses  with  the  accessory  while
passing through the foramen lacerum  posterius.   Somewhat
lower down, it also anastomoses with the glosso-pharyngeal and
with the superior cervical ganglion of the  sympathetic.   The 
PNEUMOGASTRIC NERVE.
473
branches which it  afterwards sends off, go to the neck, to the
viscera of the thorax, and to those of the abdomen, after the
following manner:—

  A.  Cervical Branches.   The Superior Pharyngeal  Nerve
(Ramus Pharyngeus) arises just below the preceding anastomo-
sis.  It is directed downwards on  the internal face of the in-
ternal carotid, and having sent  an  anastomotic filament to the
glosso-pharyngeal  nerve, it forms on the  middle constrictor of
the pharynx, the pharyngeal plexus which  is re-enforced by
filaments from the superior cervical ganglion of the sympathetic,
from  the  glosso-pharyngeal, and from the superior laryngeal
nerve.  The filaments departing from this  plexus,  are  spent
principally upon the middle constrictor, but a few of them also
go to the superior constrictor ; and  others, descending along the
primitive carotid,  anastomose with ramifications from the glos-
so-pharyngeal, and from the superficial cardiac nerve.   A fila-
ment, called the inferior pharyngeal, sometimes proceeds from
the pneumogastric a little below the other, and also is spent upon
the pharynx.
   The pneumogastric, at the place  where  it detaches these pha-
ryngeal branches,  or a little above them, becomes softened  in
its  texture, enlarges somewhat, and  has the  fasciculi which
compose  it moderately separated  by a sort of red gelatinous
substance interposedvbetween them.   This portion is its  gang-
liform plexus, and into it is joined one or more branches from
the accessory nerve.

   The Superior Laryngeal Nerve (Nervus Laryngeus Superior)
arises from the  gangliform plexus.  It descends between the
internal  carotid and the  superior cervical  ganglion, anasto-
mosing on the way with the latter, with the pharyngeal plexus,
and  the  hypoglossal  norve;  it then divides into an external
and  an  internal laryngeal branch.  The former sends its fila-
ments to the muscles situated on the fore part of the thyroid
cartilage; to the thyroid  gland; and some  of them penetrate
through the crico-thyroid membrane to the lining membrane of
the larynx.  The  internal laryngeal branch is placed above the
other; it is directed towards the thyreo-hyoid membrane, which
it penetrates and then begins  to ramify.   Some of the branches
                            41* 
474                   NERVOUS SYSTEM.
go to the epiglottis cartilage, its  covering membrane, and the
adjacent portion of the lining membrane of the pharynx.  Other
branches are distributed to the small muscles which move the
arytenoid cartilages, and to the lining membrane of the larynx.
The filaments which go to the epiglottis have an arrangement
indicated by Bichat; that of going into the foramina which per-
forate it, but they cannot be traced farther.
  The pneumogastric. afterwards does not send off any regular
branches till it  reaches the lower part of the neck.  It then de-
taches two or three filaments, (rami cardiaci,) which,  on the
riccht side, have their roots about an inch above the subclavian
artery,  and on  the left side, an inch lower down.   On the  right
side, they descend along the subclavian and the arteria innomi-
nata, on the left along the left carotid; they reach the arch of
the  aorta, and  in their  course,  as  well as there, anastomose
very freely with the superficial cardiac nerve.  The rami car-
diaci are frequently more abundant on the right side then on
the left.

  The  Inferior Laryngeal Nerve (Nervus Laryngeus Inferior,
Recurrens) is a considerable branch of the pneumogastric, which
comes off next  to the cardiac.   On the right side it arises im-
mediately after the trunk  has  passed between the subclavian
artery and the subclavian  vein.  It then winds around the sub-
clavian artery so  as to retain the latter in its loop; having thus
got behind the  artery, it then ascends towards  the larynx, on
the side of the trachea, covered by  the common carotid, and by
the inferior thyroid artery.
  In this course the inferior laryngeal  nerve detaches the fol-
lowing branches: 1. From the convexity of its loop it sends
filaments to the assistance of the cardiac  branches just spoken
of, arising from the pneumogastric, and to  those coming  from
the inferior cervical ganglion  of the sympathetic.   2. It de-
taches the pulmonary branches, the origin of which is compli-
cated with the plexus of nerves existing about their roots; these
descend in front of the  trachea, reach the pulmonary artery,
and  follow its ramifications into  the lungs; some of the  fila-
ments, however, go  to  the cardiac plexus.  3. The inferior
laryngeal  then  sends many filaments to the oesophagus; 4.
Branches which go  to the inferior  part of  the thyroid gland; 
PNEUMOGASTRIC NERVE.
475
5. Filaments to the trachea, some of which penetrate the mem-
brane on its posterior part, others go between the cartilages;
they are then distributed  to  the lining membrane and to the
mucous glands of the part.   6. The inferior laryngeal  nerve is
then distributed in branches to the inferior constrictor of the
pharynx and its  lining membrane, but the  most of its termi-
nating filaments  penetrate to the larynx, between  the thyroid
and the cricoid cartilage, and are lost upon the lining membrane
of the larynx, and upon the small muscles which move  the ary-
tenoid  cartilages.  These terminating  filaments anastomose
with such as come from the  superior laryngeal nerve.
   It is generally stated by anatomists  that  the  distribution of
the inferior laryngeal nerve  to  the larynx, is confined to the
thyreo-arytenoid, and posterior  and  lateral  crico-arytenoid
muscles.  Mr. G. Rainy states, in the London Medical Gazette,
that he has repeatedly traced  its filaments, also, to the  trans-
verse and oblique arytenoid.*   The recurrent of the  left side
forms a much  larger loop than the other, and arises lower down,
inasmuch as it has to wind around the arch of the aorta, at the
origin of the left subclavian  artery: with some inconsiderable
exceptions, its course  and distribution afterwards are precisely
the same with those of the nerve of the right side.
   B.  The Thoracic Branches of the pneumogastric are as fol-
low:  The inferior tracheal nerves come from it just below the
recurrent: they  are five or six in number; some of theiVi go in
front of the trachea  and bronchia, and others behind them.
They are complicated by anastomoses with the branches of the
recurrent nerve, and with those  of  the  inferior  cervical gan-
glion, and form  a small  plexus, denominated the anterior pul-
monary, which lies  upon  the front of the root of the lung, and
has its filaments  following the branches of the pulmonary artery
through the lung.  The posterior filaments supply the structure
of the bronchus  by penetrating it, and some of them go to join
the posterior pulmonary plexus.
   As the pneumogastric  gets behind the trachea and the bron-
chus, it is sensibly enlarged and somewhat flattened, the cohe-
sion of its fasciculi  being somewhat looser.  Several filaments
depart  there  from  it, which form an  intertexture with  each
* Am. Med. Journ. vol. iv. p. 198. 
476
NERVOUS SYSTEM.
other; some  of them pass inwards, to be distributed on the
bronchus, trachea, and oesophagus^  Others, which are given
off as the nerve lies upon the posterior face of the rpot of the
lung, amounting to six or seven in number, but being of various
sizes, run transversely outwards, and form an intertexture with
one another.   The latter are joined by filaments from  the infe-
rior  cervical  and the first dorsal ganglion of the sympathetic,
and thus constitute the posterior pulmonary plexus.  The fila-
ments from this plexus follow the distribution of the bronchus,
and, according to Bichat, are all destined to the mucous mem-
brane and the mucous glands of the lung; as they may be traced
piercing successively the ramifications of the bronchus, in order
to reach its lining membrane.
   On the right side, the par vagum, while furnishing the pul-
monary plexus, and for some distance lower down, is divided
into from four  to six considerable fasciculi, which form with
each  other a  plexus or series of anastomoses, having very large
meshes, and from which  proceed many filaments to  the oeso-
phagus.   Afterwards these fasciculi are assembled into  a sin-
gle cord, which proceeds on the posterior face of the  oesopha-
gus, along with it into the abdomen.
   On the left side, the par vagum, after forming the posterior
pulmonary plexus, is split into  two or three fasciculi; which
likewise furnish branches to the  oesophagus, and  unite to form
a single cord, which proceeds on the front surface  of  the oeso-
phagus, along with it into the abdomen.
   The two nerves, while descending in this way, send frequent
anastomotic filaments to each  other, and to the oesophagus.

   C.  In the Abdomen the par vagum  is distributed as follows:
Filaments  are  sent from  each  nerve, which  form  a plexus
around the cardiac orifice  of the stomach.  The right  nerve
is  then divided into many  branches;  some are distributed on
the posterior face of the stomach, others  go  along the lesser
curvature of  this  viscus, and reach thereby the pylorus, where
they anastomose with  filaments from the left nerve, and from
the gastric plexus of the sympathetic; others  go behind the
stomach  to join the  solar  plexus, and  are blended  with the
latter in  its distribution to  the  liver, vena portarum, duode-
num, and pancreas.  The left  par vagum, being placed in front 
THE SYMPATHETIC NERVE.
477
of the cardia, is resolved into several radiating filaments or
fasciculi, some of which  supply  the  anterior face  of  the  sto-
mach, others go  along its lesser curvature to the pylorus, to
anastomose with  the  right nerve  and the gastric branches of
the sympathetic, and are finally blended, after the same manner
as the preceding, with the solar plexus.
                    CHAPTER II.


              OF THE SYMPATHETIC  NERVE.*

  The Sympathetic Nerve (Nervus Sympatheticus Magnus, In-
tercostalis Maximus, Gangliosus,) differs, in a great number of
respects, from every other nerve of the body; and if we were
actuated only by its  peculiarities, with Bichat, Meckel, and
others, we  might, with great propriety, set it apart as some-
thing having a claim to  an  insulated description and location.
The dissection of it, however, is  so much blended with that
of the par vagum, that  the descriptions of the two go best
hand in hand, and are, therefore, most  conveniently studied to-
gether.
  This  nerve consists in  a series or chain of ganglions, extend-
ing from the base of the cranium to the lower end of the sa-
crum.  They are placed  on  the lateral  part of the bodies of the
vertebras, are united to each  other by intermediate  nervous
cords, and send off continually filaments to the adjacent or-
gans.   With the exception  of the  neck, there is a ganglion for
each intervertebral space,  both of the  true vertebras and sa-
crum.  Besides these ganglions, there  are  others which are si-
tuated around the trunks of some of the large vessels of the ab-
domen.
   The  superior extremity of the sympathetic nerve, opposite to
the transverse process of the second cervical vertebra, and be-
* Anton. Scarpa. Tabul. Neurolog. 
478
NERVOUS SYSTEM.
hind the internal carotid  artery, forms a ganglion, which, for
the purpose of description, may be considered as the first of the
series.   This ganglion is the superior cervical.
   The nervus motor externus oculi, in passing through the ca-
vernous sinus, and the Vidian nerve, in passing by the point of
the petrous bone, both send a filament downwards  through  the
carotid canal; which  two filaments unite to form a single cord,
that runs into the  superior extremity  of this ganglion.   The
filament from  the Vidian nerve is, as mentioned, the deep pe-
trous nerve.  The  common view taken by  anatomists of this
nervous connexion is, that it is the beginning of the sympathe-
tic, though, by Bichat, it is described as the  termination, or one
of its extremities.   The distinction, though  important physiolo-
gically, is less so when the object is simply to describe the course
and anatomical  relations of this nerve, as they may be equally
understood by either mode of description.
   The branch from the deep Petrous  most frequently  forms, on
the external face of the internal carotid, in the cavernous sinus,
or more  generally in  the carotid canal, a  ganglion, (Ganglion
Cavernosum, Caroticitm,) discovered by Laumonier.  Some ana-
tomists consider this  ganglion to  arise from one  or  more fila-
ments, from the motor externus.*  From the ganglion caverno-
sum, it has, of late,  been ascertained that filaments may be
traced to the ganglion of Gasser, (Plexus Gangliformis,)  of the
trigeminus,  to the pituitary gland, to the infundibulum; and,
moreover, a fasciculus which, according to  H. Cloquet, forms a
plexus around the ophthalmic artery, and may be traced along
all its  branches, even the central artery of the  retina." This
plexus anastomoses with the lenticular ganglion, and conse-
quently establishes a direct nervous communication between the
sympathetic, and the first branch of the fifth pair.   The know-
ledge of this connexion  has caused anatomists to locate the len-
ticular ganglion  and the ciliary nerves in the ganglionic system
of the sympathetic, as forming a part of the latter.
  The sympathetic, in  descending  the  neck, is placed behind

  • M. Lobstein, in his Essay on the Sympathetic, a work of much merit, has
attributed this ganglion to the deep petrous nerve, in which I thought for manv
years he was m.staken, though renewed observations have now convinced me of
his correctness.  Paris, 1823. 
                  THE SYMPATHETIC NERVE.                479

the carotid artery and internal jugular vein.  It is commonly
said to be enclosed in the sheath of these great vessels, but the
statement is loose and inaccurate, as it is fastened to the front
surface of the longus colli muscle by cellular substance distinct
from  the  sheath, as  may  be manifested by pushing a  knife
handle between them and  raising  up the sheath.  The cord
which comes down from the carotid canal is close to the pneu-
mogastric and  hypoglossal  nerves.  Having formed  the first
cervical  ganglion, it descends as mentioned; and, opposite to
the space between the fifth and sixth cervical vertebras, it  is
again enlarged into  the Middle Cervical Ganglion, which  is
much smaller and more  irregular than the first.  The sympa-
thetic  is then traced with  some difficulty, in consequence  of
the numerous branches coming from  it;  but, with attention, a
trunk  may  be found as the  continuation of it.  This  trunk
passes to the interval between the head of the first rib and the
transverse process of the last cervical vertebra, and there en-
larges into another ganglion, called Inferior Cervical or First
Dorsal.

   To understand well the connexions of the sympathetic in the
neck, each of the cervical  ganglions  must be studied particu-
larly.

   1st. The  Superior  Cervical Ganglion varies  considerably  in
its extent; commencing very generally opposite to the second
cervical vertebra, it is sometimes  elongated  to the lower part
of the third  and even of the fourth.  In cases of unusual elon-
gation, it is smaller than in  others.
   It  sends  off, from its external  margin, several filaments,
about four, which cross the anterior face of the rectus anti-
cus major muscle, and  terminate  by anastomosing with the
anterior fasciculus of the occipital  nerve and of the first three
cervical: when the ganglion is short, the two  lower  filaments
come from  the sympathetic below  it, instead of from the gan-
glion.
   Several filaments also proceed from this ganglion to the con-
tiguous muscles on the vertebral column, to the pharynx, to the
larynx, and to the thyroid gland.
   This ganglion also sends off what are called its  Anterior 
480                   NERVOUS SYSTEM.
 branches, which are peculiar for their reddish colour and for
 their softness; the latter quality has obtained for them the name
 of Nervi MoUes.  They  may be  referred, by their  position, to
 three  orders.   The superior  ascend to anastomose with the
 pneumogastric,  hypoglossal, and  facial nerves, near their exit
 from the cranium.  The middle  are two or three in number,
 but immediately divide into many filaments, forming the  caro-
 tid plexus  by assistance from the pneumogastric,  glosso-pha-
 ryngeal, and facial nerves.  Some of the branches of this plex-
 us descend behind the primitive carotid, at the place of its bi-
 furcation, and accompany it to its  origin, continually interlacing
 with each other.  Others surround, after the same manner, the
 external carotid, and  subdivide into a plexus for  each of its
 branches, so that very fine filaments may be traced along the
 superior thyroidal, the lingual, facial, occipital, and  temporal
 arteries.  These nerves are, for the most part, difficult to trace,
 from their  extreme tenuity.  The  primitive  branches, from
 which these plexuses come, are  sometimes previously united
 into a small ganglion,  which serves as a common centre to all
 these nervous irradiations.  The third order of anterior branches
 amounting to from four  to six, come either from the ganglion
 or from the sympathetic just below it.  A cord  formed by
 their union, called the Superficial Cardiac Nerve, descends on
 the external  side  of the  primitive carotid, anastomosing with
 filaments from the pneumogastric and from the descendens noni.
 It gives small ramifications to  the contiguous parts, as to the
 pharynx, oesophagus, the sterno-hyoid and thyroid muscles.  It
 terminates  in the lower part of the neck, by detaching anasto-
 mosing branches to the branches  of the recurrent nerve; some
 of them also go along the inferior thyroid artery to  the  thy-
 roid gland.   What remains of it i's lost in the middle cardiac
 nerve;  for it cannot  be  traced, in  an  insulated  and distinct
 manner, to  the heart; from which cause, its appellation is ob-
jectionable.
   2.  The Middle Cervical Ganglion,  placed  intermediately to
the fifth and sixth cervical vertebras,  upon the longus colli mus-
cle, is there concealed  by the common carotid, the internal ju-
gular vein, and the pneumogastric nerve.  It is sometimes de-
ficient : according to Meckel, in the proportion of once in three
times.   In my own dissections I have always found  it, though 
THE SYMPATHETIC NERVE.
481
under various circumstances of size and form.  It is more flat-
tened than the preceding, and  never so long.   Sometimes it  is
double.  Like the preceding, it has a great many filaments at-
tached to, or emanating from it.
  The external filaments, amounting to about three in number,
pass from it to the anterior fasciculi of the fourth, fifth and sixth
cervical nerves,  between the origins of the scaleni  muscles.
Some of its filaments accompany  the inferior thyroid artery,
and, along with the superficial  cardiac, form a plexus around
it, which reaches to the thyroid gland.
  The Middle Cardiac Nerve is formed by several of the ante-
rior branches, collecting into  a single  chord.   The latter de-
scends along the external side of the primitive carotid, crosses,
on  the right side of the body, the root of the subclavian artery,
and then going along the posterior  face of the arteria innomina-
ta,  it gets between the aorta and the bifurcation of the trachea,
where it is merged in the commencement of the cardiac plexus
of nerves.   On the left side, the middle cardiac nerve is formed
by  an assemblage of filaments from the middle and inferior cer-
vical ganglions, which descend along the left subclavian artery
to the aorta, and are joined, on the front of the latter, by the su-
perficial cardiac  nerve.  On both sides, these cardiac nerves
form intricate anastomoses with the pneumogastric  nerve  and
its  recurrent branch.

  3. The Inferior Cervical Ganglion, situated  as mentioned,
near the head of the first rib, like the others, is subject to vari-
ations  in its form and  size.  Several filaments may  be traced
between it and the middle  cervical ganglion.  One  penetrates
into the canal of the transverse processes along with the verte-
bral artery, and, forming a plexus around it, may be traced dis-
tributing branches to the heads of the  contiguous muscles, as
high up as the second cervical vertebra.
  The external branches of the inferior cervical ganglion  are
numerous and small.  Some of them anastomose with  the an-
terior fasciculi of the two or three inferior cervical and the first
dorsal nerve.  Others form a plexus around the subclavian ar-
tery, and follow the latter, in its distribution, to the  upper  ex-
tremity and to the shoulder.
  The anterior branches of this ganglion  concur, after some
     Vol. II.—42 
482
NERVOUS SYSTEM.
anastomoses with each other, to form a single chord, the Infe-
rior Cardiac Nerve, which goes, on the right side, along the ar-
teria innominata, to be blended with the cardiac plexus.  On
the left side, it is not so  distinct, but  is blended with the mid-
dle cardiac nerve, and forms its inferior root.


          Of the Cardiac Plexus of the Sympathetic.

   The Cardiac Plexus (Plexus  Cardiacus) is  situated between
the arch of the aorta,  and the lower part of the trachea and the
bronchia, and  extends from the division of the pulmonary ar-
tery to the commencement of the arteria  innominata.  It  is
formed, almost wholly, from the branches  sent by the three
cervical ganglions of the  symphathetic of each side, and princi-
pally from that of the  middle one, or  the middle cardiac nerve.
The filaments which  come  from the recurrent nerve and the
par vagum are blended into  the cardiac plexus in such a man-
ner that  they cannot  be  traced  separately to the heart.   It is
worthy of remark, that  the  three cardiac nerves of the right
side are more  constantly found than the same number on the
left, in  consequence of the lower one of the latter soon merging
itself,  after its origin  into the  middle cardiac nerve  of that
side.
  The cardiac plexus  is formed by the common assemblage of
the nerves from the two  sides of the neck, and is therefore sin-
gle.  From  this plexus   arise  all the nerves which go to the
heart, so that in  tracing them the distinction between right and
left is confounded.  Scarpa has pointed out, in this  circumstance,
an analogy between them and the nerves which supply  the ab-
dominal viscera.
  The cardiac plexus  is distinguished by the  softness of its tex-
ture.   For the  purpose of description, its branches may be di-
vided into Anterior, Posterior, and Inferior.

  The Anterior Branches  are but few.  They are  found on the
front of the arch of the aorta.   One of them crosses it  on the
right side of the arteria  innominata; others  cross it from the
foot of the left  carotid and  subclavian, downwards.  In  both 
                   THE SYMPATHETIC NERVE.                483

cases, several of the terminating filaments run into the anterior
coronary plexus.*

   The Posterior Branches are more numerous; but run only a
short course, when they are merged in the anterior pulmonary
plexus formed by the par vagum.

   The Inferior Branches are the largest and the most abundant.
Some  of them follow the  pulmonary artery until its entrance
into the lungs, others are distributed upon the pulmonary veins;
but the greater number of them are arranged into two plexuses
called Coronary, from their observing the eourse of the corona-
ry arteries.  The  posterior coronary plexus  is larger than the
other.  It  reaches the base of the heart, along the pulmonary
artery, and has its filaments'distributed  principally to the left
auricle and left ventricle, observing the course of the left corona-
ry artery and of its branches.  The anterior coronary plexus gets
in front of the heart, between the aorta  and the pulmonary ar-
tery.  It anastomoses freely at its superior part with the other,
and is then distributed to the right auricle and ventricle, along
the course of the  right coronary artery and of its branches.


         Of the Thoracic Ganglions of the Sympathetic.

   These ganglions are twelve in number, and are placed on or
 near the heads of the ribs, at  the  commencement of  each in-
 tercostal space,  and  are  only covered  by the pleura.  Their
 shape is  irregular, and they differ also in  size, being always
 smaller than the cervical ganglions.  The chord of the sympa-
 thetic is continued, successively, from one ganglion to another,
 so that they form  a complete chain by their connexion with  each
 other.
    From  each ganglion there proceeds one  or  more external
 branches, which go outwards to anastomose with the intercostal
 nerve of the corresponding part.   Each ganglion also detaches
 one or more  internal  branches or filaments to the adjacent parts
* Scarpa. 
484
NERVOUS SYSTEM.
lying on the vertebral column:  some go  to the cellular sub-
stance, others to the longus colli muscle, others to the aorta,
others to the cardiac and to the  pulmonary plexuses.  Among
these internal branches there are several which concur to form
the Splanchnic Nerves, of which there are two; the Great and
the Small.

   The Great Splanchnic Nerve arises,  by filaments, from the
sixth to the ninth or tenth thoracic  ganglions, inclusively; one
or more filaments coming from each ganglion.   They are di-
rected downwards and forwards on the sides of the dorsal ver-
tebras, covered by the pleura, and  unite,  successively, into a
trunk  about the eleventh dorsal vertebra.  This trunk pene-
trates into the cavity of the abdomen, between the middle and
the internal head of the lesser  muscle of the diaphragm, or by
the opening for the aorta.
   Having got into  the  abdomen, the great splanchnie divides
into several fasciculi, which, diverging from each other, are con-
cealed on the right side by the liver, and on the left by the sto-
mach. On each side of the aorta there is a large ganglion formed
by an assemblage of several smaller ones; it is called the Semi-
lunar.  Into it terminate, for the most part, these fasciculi: some
of them, however, go immediately into  the solar plexus, which
emanates from the semi-lunar ganglion.

   The Small Splanchnic Nerve is derived, by filaments, from
the tenth and the eleventh thoracic ganglions.  Having united,
they penetrate the crus of the diaphragm, and, reaching the ab-
domen, the trunk is  divided into two branches, of  which the
uppermost ascends to join the great splanchnic before its divi-
sion, and the lower descends to join the renal plexus.

  Posterior Renal Nerves.—Besides these two splanchnic nerves,
it  frequently happens that there are others which come  from
the eleventh and twelfth thoracic ganglions, and from the com-
municating branch between the last thoracic and the first lum-
bar.  They unite into a trunk which goes to the renal  plexus,
and have been called, by Walter, the Posterior Renal Nerves. 
THE SYMPATHETIC NERVE.
485
                    Of the Solar Plexus.

  The Semi-lunar Ganglion, situated, as mentioned, on the side
of the aorta, is somewhat semicircular or oval, and is about an
inch long; its form, however, is much diversified in different
subjects.  The  several ganglions of which it is composed, are
frequently fused into a single one.  That  of the right side is
more voluminous than the  other, and is  placed between the
ascending vena cava and the crus of the diaphragm, somewhat
above the right renal artery. That of the left is situated upon
the left crus of the diaphragm, somewhat below the splenic ar-
tery.  Between their inferior extremities, there are generally
two or three smaller ganglions.
  These several  ganglions are  united by numerous filaments,
which send out many ramifications, and anastomose freely with
each other.
  The preceding arrangement  may be considered  as the root
of  the Solar Plexus, which extends from the cceliac artery to
the lower margin of the emulgents, and as it is common to the
ganglions of the two sides, it is an inch and a half or two inches
wide.   Bichat  has  very  properly remarked, that  this plexus
seems to exist for the aorta, as  all the divisions which it sends
out follow so exactly the branches of this  artery, that we  are
forced to adopt the latter as the basis of the description.  The
intertexture and the number of the branches emanating from
the solar plexus are so complicated, that a description of indi-
vidual branches would be almost endless, as well as unintelli-
gible; anatomists are, therefore, generally agreed  to describe
the plexus according to the  order of the arteries which its de-
tachments adhere to and surround.

  1.  The Diaphragmatic Plexus consists of a  few filaments
coming from the superior part  of the solar, and following the
course of the phrenic arteries.   Some of them anastomose with
the terminating filaments of the phrenic nerve, in the thickness
of the diaphragm.

  2. The Plexus which surrounds the  Codiac  Artery, like it, is
                           42* 
486
NERVOUS SYSTEM.
quickly disposed into three divisions, which follow the branches
of this artery.

  a. The Superior Coronary  Plexus of the stomach,  fs  the
smallest  of the three.  It attends  the  corresponding  artery
along the lesser curvature of the stomach to the pylorus, sup-
plying the stomach continually with very fine filaments.  In
its course, it anastomoses  with the par vagum, and sends fila-
ments to the hepatic plexus.

  h. The Hepatic Plexus  is the largest of the three.   It sur-
rounds the hepatic artery and the vena portarum, and, in its
eourse, detaches branches which go with the right gastro-epi-
ploic artery to the great curvature of the stomach, and consti-
tute the inferior coronary plexus.   Branches are  also sent to
the pancreas and to the duodenum.  The hepatic  plexus then
enters the transverse fissure of the liver, and its branches may
be traced to the several lobes and to the gall-bladder..

  e. The Splenic Plexus, is but small, and surrounds the sple-
nic artery.  The few branches of which it is composed, anas-
tomose but rarely with each other.   Some, of them are distri-
buted upon the pancreas,  along with the pancreatic branches
of the splenic artery; others go with the left gastro-epiploic ar-
tery to the left extremity and the greater curvature of the sto-
mach; the remainder penetrate into the substance of the spleen,
through its fissure, along with the branches  of the splenic ar-
tery.

  3. The Superior Mesenteric Plexus is derived from the solar,
near the superior mesenteric artery; it descends  some  short
distance on the aorta, before  it reaches the latter.  It passes
with the artery between the pancreas and the duodenum, and
is then included between the two laminas  of mesentery; it is
then distributed, by very numerous  filaments, along with  the
branches of the artery, to  the whole of the small intestines, to
the  ccecum,. and to the ascending and; transverse colon.

  4. The  Renal Plexus, one on each side, is derived from  the
lower lateral part of the solar.   Two or three ganglions, on the 
THE SYMPATHETIC NERVE.
487
root of the renal artery, contribute to it, and it is also re-en-
forced by an addition from the lesser splanchnic  nerve.  The
branches which form this plexus do not anastomose  much, till
they get near the kidney; they then penetrate into its substance,
through the fissure.  Some filaments from this plexus go to the
capsulae renales: others follow the course of the spermatic ar-
tery, and constitute  the  spermatic  plexus which goes to the
testicle in the male, and  to the ovarium in the female.

  5. The Inferior Mesenteric Plexus is a continuation of the
solar, on the anterior face of the abdominal  aorta. It is much
smaller than the superior mesenteric plexus, though it receives
continually, in its descent, filaments from the lumbar  ganglions
of the sympathetic.  It forms frequent anastomoses around the
root of the inferior mesenteric artery, and near the superior
strait of the pelvis, is resolved into two columns of fibres. One
column is  distributed along with  the artery to the rectum, to
the sigmoid flexure of the colon, and to the left section  of the
latter, thereby anastomosing with the colic branches  of the su-
perior mesenteric plexus.  The other column descends into the
pelvis, in front of the sacrum, and contributes to form the hy-
pogastric plexus, but several of its branches also follow the
external and the internal iliac arteries.


         Of the Lumbar  Ganglions of the Sympathetic.

  These ganglions are five  in number, on either side, and are
placed anteriorly on the  sides of the bodies  of the lumbar ver-
tebras, near the anterior  margin of the psoas magnus muscle.
Their form is irregular;  they are smaller than the cervical gan-
glions, but larger than the dorsal.
  The last thoracic  ganglion is united to the first lumbar by a
small branch, which may be considered as the continuation of
the  sympathetic.  A deficiency of this  branch  has, however,
been several times observed by anatomists;  also  a deficiency
in the connecting nervous chord of the ganglions below.  The
ganglions themselves are inconstant in their number,being some-
times less than  five; they vary likewise  in  their situation.  It
is to be understood* however, that in a majority of subjects, the 
488
NERVOUS SYSTEM.
sympathetic goes on uninterruptedly from one ganglion to ano-
ther, sometimes by one branch; on other occasions, by two or
three.
   Each lumbar ganglion sends outwards one or more external
branches, which applying themselves to the body of the  conti-
guous vertebra, reach the corresponding intervertebral foramen
of the loins, and  join with  the anterior branch of the corre-
sponding lumbar nerve.  Some of these external branches are
spent upon the quadratus lumborum  muscle.
   Each lumbar ganglion, or the intermediate chord of the sym-
pathetic, also  detaches branches internally, which are very
small, and  more or less  interwoven with each other.  These
branches get to the abdominal aorta, and, joining  the inferior
mesenteric plexus upon it, are distributed along with the latter.


         Of the Sacral Ganglions of the Sympathetic.

   There are generally three of these ganglions  which may be
readily found:  sometimes four or five.   They are situated in
a line,  on the anterior face  of the sacrum, near the correspond-
ing foramina for the transmission of the sacral nerves; and are
united  with each other by intermediate fibres, from one to three
in number,  which are the continuation of the sympathetic nerve.
Bichat asserts, that frequently the  first of these ganglions is
not united to the last of the lumbar  by an intermediate nerve,
so that there the continuity  of the sympathetic is interrupted.
.   Each ganglion sends off,  externally, one or more filaments,
by which it is  united to the  corresponding sacral nerve: it also
detaches filaments in this direction  to  the pyriformis and the
levator ani muscles.
   Each ganglion likewise detaches,  from its internal margin,
ramifications, which go obliquely downwards  on the front of
the sacrum, and anastomose with  corresponding  filaments from
the opposite side.
   From these  ganglions many branches pass  forwards to  the
hypogastric plexus; which  is  formed by them, by the inferior
mesenteric  plexus, and  by  a  great  many filaments from  the
lower sacral nerves, principally the third.  The  plexus is dis-
tributed upon the rectum, the bladder, vesiculae seminales, and 
UPPER NINE SPINAL NERVES.
489
prostate of the male; and, in place of the two latter in the fe-
male, upon the vagina and the uterus.
  The last sacral ganglion detaches downwards  one or more
filaments, which lie  upon the front of the os coccygis, and
anastomose with the corresponding filaments .from the other
side, to form a sort of arch, the  convexity of which is down-
wards.  In this manner, terminates the chord of the sympa-
thetic nerve.
                   CHAPTER III.


        OF THE NERVES OF THE MEDULLA SPINALIS.

  The nerves of  the  medulla spinalis, with the exception of
the first, which, from its position, is generally called  the Sub-
occipital by anatomists, are arranged into cervical, dorsal, lum-
bar, and sacral, according  to the order of the inter-vertebral
foramina,  through which they pass out:  but a much better di-
vision would be Cervical,* Thoracic, and Abdominal,  Their
mode of origin, and the ganglions formed  by them, have been
pointed out in the account of the medulla spinalis,


          SECT. I—OF THE UPPER NINE SPINAL NERVES.

  These are spent upon the neck, upon the upper extremities,
and upon  the  diaphragm.   They consist in the Sub-occipital
Nerve, the Cervical, and the First Dorsal.


                 Of the Sub-occipital Nerve.

   The  Sub-occipital  Nerve (Nervus Infra-occipitalis, decimus
cerebri) is one of the smallest that proceeds from the medulla
* In this case, the term Cervical would include the first eight. 
490
NERVOUS SYSTEM.
spinalis.   It has the peculiarity, generally, of arising by a sin-
gle root, which comes from the anterior chord of the medulla
spinalis,  between the occiput  and the  first cervical vertebra.
This root consists of from two to six or seven fasciculi, situated
one above another.   When the posterior root exists, it  is very
small, is  composed  of from one to three fasciculi, and anasto-
moses with the accessory nerve.
   The trunk of this nerve passes from the vertebral cavity
through  the foramen formed  in  the  dura mater  by the verte-
bral artery; it goes out below the latter, and between the oc-
ciput and the first vertebra, behind its superior oblique process.
It there  forms  a small  long  ganglion, like the other  spinal
nerves, and then divides into an anterior and a posterior fasci-
culus.
   The anterior fasciculus is the smaller of the two;  it follows,
in some measure, the course of the vertebral artery, and going
forwards to the front of the transverse process,  is then divided
into several fine filaments, some of which go to the contiguous
muscles on the front of the vertebras; others join themselves to
the pneumogastric and hypoglossal nerves, and  to the superior
cervical  ganglion of the  sympathetic; others anastomose with
the first cervical nerve.
   The posterior fasciculus runs backwards, and  is distributed
to the recti and the  obliqui  muscles on the back of the  neck
and to the complexus,


                    Of the Cervical Nerves.

   These  are seven  in number:  the first one gets  from the
spinal cavity between  the atlas  and  the dentata, and the last
between  the seventh cervical  and  the  first dorsal  vertebra.
After  the ganglion  is  formed upon the posterior fasciculus of
each,  the trunk, made by the union of the two fasciculi, di-
vides almost immediately again into an anterior and a posterior
trunk.

                 Of the First Cervical Nerve.

   The posterior trunk is the largest, and goes directly back-
wards.   It has its filaments distributed to many of the muscles 
UPPER NINE SPINAL NERVES.
491
On the upper posterior part of the cervical vertebras, and to the
integuments of the part.  Some of the branches ascend through
the muscles, near the occiput;  and, rising up on the latter, are
distributed upon its integuments, and upon the occipito-frontalis
muscle.
  The anterior trunk is directed forwards under the inferior ob-
lique muscle of the neck, and then divides into  two branches:
the superior joins the anterior branch of the sub-occipital nerve,
and anastomoses with the first cervical ganglion of the sympa-
thetic, and with the par vagum and the hypo-glossal nerve; the
inferior joins the anterior branch of  the second cervical nerve.


                Of the Second Cervical Nerve.

   This nerve issues  between the second and the third cervical
vertebra.   Its posterior trunk is spent upon the trapezius,  com-
plexus, and other muscles on the back of the neck, and upon the
integuments of the latter; it also anastomoses with  the posterior
trunk of the nerve above and below.
   The anterior branch or trunk detaches, first of all, some small
filaments to the muscles on the front of the  cervical vertebras;
it then divides into two principal fasciculi, one of which ascends
and the other descends.
   The ascending  branch  goes upwards  and backwards, and
early in its course  anastomoses with the first cervical nerve,
thereby forming with it a nervous noose; it  then  mounts  upon
the occiput, and is distributed  upon the parts on the latter
region,  anterior to  the occipital branches  of  the  preceding
nerve.
   The descending branch turns over the posterior margin of
the sterno-cleido mastoideus muscle, and gives filaments  to it.
It is distributed afterwards by  branches, some of  which go to
the integuments of the middle and  inferior parts  of the  neck,
(nervi subcutanei colli medii et inferiores,) others go to the inte-
guments of the neck upon the  angle and the base  of the lower
jaw,  (nervi subcutanei superiores,) and one to the  external ear,
(nervus auricularus cervicalis.)
   From  the  anterior fasciculus  of  the second cervical nerve,
there proceeds a filament downwards, which  is the upper root 
492
NERVOUS SYSTEM.
 of the phrenic nerve;  another filament from it joins  the supe-
 rior cervical ganglion of the sympathetic.


                  Of the Third Cervical Nerve.

   This nerve comes out between the third  and the fourth cer-
 vical vertebra.  Its posterior fasciculus is distributed to the mus-
 cles on the back  of the cervical  vertebras, and to  the integu-
 ments of the part; anastomosing, by its branches, with the nerve
 above and  below.
   The anterior fasciculus is larger  than the posterior, and goes
 obliquely downwards and outwards at first; it sends anastomo-
 tic branches to the nerve above and below; it also anastomoses
 with the superior cervical ganglion  of the sympathetic and with
 the descendens noni.  One of its branches, being joined by  the
 branch just spoken  of,  from the  second cervical nerve, consti-
 tutes the  root of the phrenic nerve.  But the principal number
 of its branches are distributed to the integuments along the cla-
 vicle, (nervi supra-claviculares,) ihe upper part of the sternum,
 and the shoulder;  some of them going into the contiguous mus-
 cles, as the trapezius,  subclavius,  &c.  Several anastomoses
 exist between  the  branches of  this nerve and the terminating
 branches  of the nervus accessorius.

   The  three preceding cervicaf nerves form, by their anasto-
 moses with each other, a plexus, consisting in a number of large
 loops or arches, which  lie  upon the sides of the muscles con-
 nected with the transverse processes of the cervical vertebras.
 There  are commonly two series of anastomoses:  the branches
 of the  first series, form  the second  series, and from  the  latter
 proceed, for the most part, the several branches which have been
 described.   These anastomoses are covered by  the upper half
 of the sterno-cleido mastoid muscle, are involved in the cellular
 membrane surrounding  the  great vessels  of the neck, and are
 covered by  the lymphatic glands.  Their intertexture and dis-
 tribution are such, that  no  adequate idea of them can be con-
veyed without dissection.   From this plexus several branches
go to the  sterno-mastoid muscle, and it is united  above to the
sub-occipital nerve and below to the fourth cervical. 
UPPER NINE SPINAL NERVES.
493
                    Of the Phrenic Nerve.

  The Phrenic  Nerve  (Nervus  Phrenicus, Diaphragmaticus)
arises, in the manner stated above, from the anterior fasciculus
of the second and of the third cervical, and is assisted generally
by two or three filaments  from the upper part of the brachial
plexus.  It descends, vertically, on the humeral  side of the in-
ternal  jugular vein, but removed a considerable distance from it,
and is attached, by  cellular substance, to the front of the scale-
nus anticus muscle.  Getting, in its descent, to  the internal mar-
gin of the latter, it  passes into the thorax, at the inner margin
of the  first rib, between the subclavian artery and the subclavian
vein, the latter being before it.   It then goes along the superior
mediastinum to the pericardium, to the side of which it adheres
in front of the root of the lung, being between the pericardium
and the  corresponding portion  of the pleura; it  finally reaches
the diaphragm, to which it is distributed.
  Just before  the phrenic nerve reaches the diaphragm, it radi-
ates into several branches, which  interchange filaments.   Some
of the branches are distributed  to the convex surface of the dia-
phragm; others penetrate the muscle,  and are distributed in its
thickness and upon  its concave  surface.  On the right side some
of these branches pass through  the opening for the ascending
vena  cava, and, thus getting into  the abdomen, anastomose with
the solar plexus, and with  the pneumogastric nerve.
  The phrenic nerve of the left side  is nearer to the root of the
luncr than that of the right, in consequence of  the projection  of
the apex of the heart on that side.  Its distribution in other re-
spects does not present any remarkable difference from the other;
its branches radiate in the same way to the diaphragm, and sup-
ply its thickness, as well  as its upper and under surfaces.   It
sends  some filaments to the lower part of the oesophagus.
  The phrenic gives off in the neck  a few filaments to the sca-
lenus anticus,  and the rectus anticus major muscle.  It also com-
municates there, with filaments from the inferior cervical gang-
lion, and sometimes from the superior cervical.
Vol. II.—43 
494
NERVOUS SYSTEM.
            Of the Four Inferior Cervical Nerves.

  The trunks of these nerves, on issuing from the intervertebral
foramina, have one general mode of distribution, which permits
them to be described together or in common.
  The posterior branches are much smaller than those of the
preceding cervical nerves;  they go  backwards  between  the
complexus and the transversalis colli, and leave  filaments in
their passage with them;  they then reach the splenius  and the
trapezius, to which and to the integuments  of the neck they are
distributed.
  The anterior branches  are large; they appear on the side of
the neck,  between the  scalenus anticus and medius muscles;
sometimes perforating the substance of one or the other of these
muscles.  They each detach filaments to the sympathetic.  The
fourth, also, commonly sends one to the phrenic.   They then
form the Brachial Plexus.


  Of the Brachial Plexus and the Nerves of the Upper Extremity.

  The Brachial or the Axillary Plexus is formed by the junc-
tion and the intertexture  of the* four inferior  cervical nerves,
and the first dorsal or  thoracic.  It extends from the scaleni
muscles to the axilla, on a level with the neck of the os humeri.
The nerves at first converge, and are situated somewhat be-
hind the subclavian artery where it passes over the first rib;
but are at various heights above it, according to  their origin,
with the exception of the first dorsal nerve, which has to as-
cend in order to pass out of the thorax.
  The plexus is formed in the following manner.  The fourth
and the fifth cervical nerves unite near the scaleni muscles into
a single trunk, which runs a short distance downwards, and
then splits into two.  The seventh cervical and the first dorsal
do the same.  The sixth cervical is the central nerve of the
plexus, and after going downwards two or three inches, it bifur-
cates also.  Combinations of these primary divisions are formed,
which  are dissolved, and  then reformed, in such a way that a
thorough intertexture of the original nerves takes place.  This 
UPPER NINE SPINAL NERVES.
495
intertexture surrounds, the axillary artery somewhat like the
braids of a whip-cord, from the clavicle to the os humeri below7
its head.  In this course the axillary plexus passes along with
the artery between the subclavius muscle and the  first rib, lies
in contact with the superior part of the serratus major anticus
muscle, and immediately below the articulation of the shoulder
joint.  The axillary vein is in front of it.
  The nerves which proceed from the axillary plexus are the
Scapular; the thoracic;  the Axillary; the two cutaneous; the
Radial; the Ulnar; and the Median.   They supply the superior
extremity, including the  shoulder and the axilla.

   1.  The Nervus Scapularis is a small branch coming common-
ly from the upper part of the plexus,  as formed by the fourth
cervical nerve.  It goes backwards in company with the arte-
ria dorsalis superior scapulas, through  the notch or foramen of
the upper costa of the scapula; and having thus got to the pos-
terior face of the latter, it gives filaments to the supra spinatus
muscle; continuing its course then on the posterior face of the
cervix scapulas, it is lost in filaments upon the infra-spinatus and
teres minor muscles.

   2.  The Nervi Subscapulars of Bichat present  some varieties
in their origin; occasionally tltey come  from the  same  trunk,
but commonly each one has its peculiar root from the  central
parts of the axillary plexus.  There are generally three of them.
One of them  descends behind the axillary vessels, between the
subscapularis and the serratus major anticus; it crosses the teres
 major, and is lost upon the  contiguous part of the latissimus
dorsi.  Another is distributed  upon the subscapularis muscle.
The third descends along the anterior margin of the subscapu-
laris for a short distance, and distributes filaments  to it, to the
 teres minor and major muscles.

   3.  The Nervi Thoracici are primarily two or three in num-
ber, and proceed from  about  the middle of the plexus.  The
 fasciculi into  which they are resolved, may be distinguished as
 anterior and posterior.  The former are distributed, by filaments,
 to the subclavian muscles, to  the pectoralis minor and major,
 and to the integuments covering the latter. The posterior thora- 
496
NERVOUS SYSTEM.
 cic has its origin somewhat concealed by the scalenus anticus
 muscle.   It descends into the axilla, adhering to the serratus
 major muscle for  some  distance, and is  then distributed by
 many filaments to this muscle.

   4. The Nervus Axillaris, or Circumflexus, comes from the in-
 ferior part of the plexus.  Immediately after its origin, it goes
 downwards and outwards over the upper extremity of the sub-
 scapularis muscle. It then winds around the os humeri, between
 the teres  minor and major muscles, observing the course of the
 posterior  circumflex artery, and, finally, terminates on the un-
 der surface of the deltoid muscle.
   This nerve sometimes gives off the subscapular nerves, and,
 indeed, it is usual for anatomists to include the description of
 the latter in it.  As it turns around the bone, it divides into two
 principal  trunks; the superior goes to the inferior margin of the
 infra-spinatus, and to the posterior margin of the deltoides;. the
 inferior is distributed principally in the substance of the deltoid
 muscle, but some of its  filaments, by perforating the latter,
 reach the skin, and  constitute the nervus  cutaneus  humeri.
 Filaments go from the nervus axillaris, in the early part  of its
 course, to the subscapularis and the two teres muscles.

   5. The Arervus Cutaneus Internus*  arises from the lower
 part of the axillary plexus, and  is one of the smallest of those
 which go to the arm.  It  is situated between the median and
 the ulnar  nerve, and adheres almost as far as the elbow, to the
 basilic vein.   In its descent, this nerve detaches several small
 filaments, which, perforating the fascia of the arm, are distri-
 buted to the integuments of the biceps muscle, and to those on
 the internal face of the triceps.
   Somewhat above the bend of  the elbow,  at the place where
 the median basilic vein joins the basilic, but occasionally some
inches higher  up, the internal cutaneous becomes  superficial,
and splits  into two branches of nearly equal magnitude, which
diverge but little from each other at first.  The branch nearest
the internal condyle of the os humeri, lies in front of the basi-
lic vein, as it passes over the elbow joint; and continues in this
* Antonius and Caldani, Tabul. CCLVIU, 
UPPER NINE SPINAL NERVES.
497
position for two or three inches:  it goes down the front of the
fore arm on its ulnar side, but inclines continually to the back
of the fore arm.  In this course, it detaches small ramifications
to the integuments about the  internal condyle, and  about the
heads of the  flexor muscles; it also detaches continually, from
its sides, small filaments  to the integuments of the ulnar side of
the fore arm  both anteriorly and  posteriorly, some  of which
reach to the  hand.   The other, being the  anterior, or the ex-
ternal branch of the internal cutaneous, which  is nearer the
radius, passes beneath the median basilic  vein, about six lines
from the basilic; but, just before it does so, it detaches a very su-
perficial cutaneous filament, which crosses in front of the me-
dian basilic vein about its middle, and is lost a little below the
bend of the arm.  The anterior or outer branch of the internal
cutaneous having got from beneath the median basilic vein,
goes superficially as far as the middle of the fore arm without
sending off any filaments of note;  it is then divided successive-
ly into several,  which diverge  to  supply the skin down  to the
wrist.

   6. The Nervus Musculo-Cutaneus, or Cutaneus  Externus, is
somewhat larger than the preceding, and arises from about the
middle  of the brachial  plexus.   It descends a short distance,
and then perforates obliquely the upper part  of the coraco-
brachialis muscle.   Having passed through this muscle, it con-
tinues its  course obliquely, between the brachialis internus and
the biceps flexor, and, finally, makes its appearance superficial-
ly on the  outer side  of the tendon of the latter.   In this course,
it distributes filaments to the  several muscles  with which it is
connected.
   It afterwards passes the elbow joint under the median cepha-
lic vein near its middle, and descends between  the skin and
the fascia of the foije arm, near the outer margin of the me-
dian vein, to the  hand:  in this course, it  is parallel with and
on the front  of the supinator radii longus.  It distributes many
filaments to  the corresponding integuments on the radial side of
the fore arm, and, having at length got  near the lower end  of
the radius, it divides into two  orders of fibres, one  of  which
is distributed to  the integuments on the dorsal, and the other
                             43* 
498
NERVOUS SYSTEM.
to those on the palmar side of the hand, about the root of the
thumb.

  7. The Nervus Radialis, or Musculo-Spiralis, arises  from
the  upper portion of the brachial plexus, but in such a  way,
that filaments from almost every part of the  latter run into it.
It is a large trunk which winds spirally around the os humeri,
between the triceps muscle and the  bone, by entering the fis-
sure between the  first and the  third  head of the triceps.  It
appears on the outside of the os humeri, between the brachialis
internus and the  triceps muscle;  running for some  inches in
contact with their intermuscular ligament.  While beneath the
triceps, it sends several branches to its heads.   There are three
principal trunks afterwards from this nerve.
  a. The Ramus Superficialis  Dorsalis  is sent from  it on a
line with the point of the deltoid muscle.  This branch then
goes just below the skin, parallel with and over the external
ridge of the os humeri;  it,  of course, crosses  the origin of the
muscles of the external condyle.  It continues surperficial  on
the  posterior external edge of the supinator  radii longus mus-
cle, and terminates  in  the integuments on  the  back of the
hand.
  The continued  trunk of the muscular spiral  goes in the  inter-
stice between the extensor muscles, and the brachialis internus,
and, at  the external  condyle,  divides  into the other two
branches, from  which  filaments proceed to the contiguous
heads of the muscles.
  b. The Ramus Profundus Dorsalis perforates the supinator
brevis muscle, getting beneath the radial extensors to the back
of the fore-arm; it is  then distributed in numerous filaments to
the muscles on the back of the fore arm, some of its branches
reaching to the wrist.
  c. The Ramus Superficialis Anterior seems to be a continua-
tion of the main  trunk of the nerve, and descending  at the an-
terior  margin  of the supinator  radii  longus muscle, it joins
with the radial artery and  continues in its company  to a short
distance below the middle of the  radius.*  Here it crosses the
bone obliquely beneath the  tendon of the  supinator longus,

         *  This position gives the whole nerve the name of radial. 
               NERVES OF THE UPPER EXTREMITY.           499

and  then  divides into a palmar  and a dorsal  ramuscle: the
first being distributed to the  muscles and integuments of the
thumb, the second terminating go  as  to supply the back of the
hand, of the thumb, fore, middle,  and ring fingers to their ex-
tremities.

  8.  The  Nervus  Medianus  descends the  arm at the  inner
edge  of the biceps  muscle;  along the anterior surface of the
brachial artery, adhering firmly to it, and the deep-seated veins,
by cellular substance.  As far as the elbow, it sends off no
branch of importance.  There it lies at the  side of the biceps
tendon, crosses the lower part of the brachialis  internus, and is
beneath the aponeurosis of the biceps.  It then perforates the
pronator  teres and  gets between the flexor sublimis digito-
rum, and the flexor longus  pollicis, and enters the palm of
the hand  under the ligament of the wrist, at the radial edge of
the tendons of the flexor sublimis.   In  the  palm it is situated
beneath the aponeurosis palmaris and the arcus sublimis of the
arteries.
   The  median nerve dispenses  the  following  branches:—At
the bend  of the  arm, it furnishes filaments to the heads  of the
first  layer of muscles of the fore  arm; and a little below, it de-
taches  the nervus interosseus, which supplies filaments to the
flexor longus  pollicis and flexor profundus digitorum.  The in-
terosseous nerve then descends with the interosseous  artery in
front of the interosseous ligament, and terminates in the prona-
 tor quadratus.
   Before the  median nerve reaches the wrist, it sends a branch
 which supplies with  filaments  the muscles and integuments of
 the ball of the thumb.  In  the  palm  of the hand, it divides and
 subdivides so as to send a  branch to each side of the  thumb, of
 the fore,  and  of the middle finger, and to one side of the ring
 finger.   These branches go  along with the arteries to the ends
of the fingers and thumb.

   9. The Nervus  Ulnaris  comes from the lowest  section of
 the  brachial  plexus.  It descends along the internal anterior
 part of the triceps muscle, in a groove formed between it, and
 the  intermuscular ligament: it diverges, in this course, gradu-
 ally from the median nerve till it reaches the elbow,  when it is 
500                   NERVOUS SYSTEM.
 at its greatest point of separation.  At the elbow, it is behind
 the internal condyle, in the groove between it and the olecra-
 non, and separates the two heads of  the flexor ulnaris muscle.
 It then gets to ihe fore arm between  this muscle and  the flexor
 profundus  digitorum, and continues between them  to within
 two inches of the wrist joint, when it detaches the Ramus Dor-
 salis.
   The Ramus Dorsalis dips between the ulna and the tendon
 of the flexor ulnaris, runs along the internal margin of the ulna
 to the carpus; it then divides into ramuscles, which supply  the
 ulnar side of the integuments on the  back of the hand, and on
 the backs of the last two fingers.  At the interval behind, be-
 tween  the  heads  of  the  metacarpal  bones of the  middle and
 ring  fingers, a considerable ramuscle joins one from the branch
 of the muscular  spiral nerve which attended  the  radial  ar-
 tery.
   The Ulnar Nerve,  having  given off this dorsal  branch,  de-
 scends along the radial margin of the tendon of the flexor ul-
 naris and the os pisiforme, above  the annular  ligament, to  the
 palm  of  the  hand.  Getting beneath the aponeurosis, it there
 detaches first a deep-seated branch, which penetrates the mus-
 cles of the little finger to supply them, the interossei, and  the
short flexor of the thumb.  The  ulnar nerve  then furnishes a
superficial branch, and afterwards divides into three;  one  for
the ulnar side of the little finger, another for  the opposing sides
of the little and ring finger, and a third which joins the most
internal digital branch of the median nerve.
          SECT. II.--OF THE THORACIC SPINAL NERVES.

  The Dorsal or Thoracic Spinal Nerves  (Nervi  Thoracici,
Dorsales) consist  in twelve  pairs,  the  first pair goes through
the  intervertebral foramen,  between the first and the second
dorsal  vertebra,  and the twelfth pair  between  the  last dor-
sal and the first lumbar vertebra.   The common trunk, formed
after the ganglion of each nerve, goes but a short distance when
it divides into an anterior and a posterior branch.

  The Posterior  Branch (Ramus  Dorsalis) of  each  nerve, 
THORACIC SPINAL NERVES.
501
goes  backwards between the  transverse process of the corre-
sponding vertebras, and, having got beneath the multifidus spinas,
is commonly subdivided into  internal and  external ramuscles.
The internal are the smaller, and are distributed upon the mus-
cles lying upon the spine, as the multifidus,  the  sacro-lumbalis,
longissimus dorsi, and so on: their terminating  filaments reach
the skin.   The  external branches descend  obliquely outwards
beneath the longissimus dorsi, and then issue between the latter
and the sacro-lumbalis, to both of which they dispense filaments:
they  afterwards are divided into branches, which go to the tra-
pezius, latissimus dorsi, rhomboideus, and to the corresponding
integuments.

   The Anterior Branches of  the Dorsal Nerves (Rami Sub-
costales)  correspond with the  intercostal  spaces of  the ribs.
Each one, in a short course after its origin, applies itself to the
rib just above it, and accompanies the intercostal vessels in the
groove, formed in the under margin  of each rib.  After it pro-
ceeds about two-thirds of the length of the rib, it separates gra-
dually from it, and  goes nearer the  middle of the intercostal
space and the superior margin  of the rib below.  To the angle
of the rib, each nerve  is only covered in front by the pleura,
but afterwards  it goes between the intercostal muscles.  Near
the sternum, the branches become superficial by escaping from
between the  intercostal muscles, and are distributed  upon  the
pectoral  muscles, and the adjacent skin.   These  terminating
branches of the five or six inferior dorsal nerves go to the upper
porlions of the abdominal  muscles  and their integuments.   Not
far from its origin,  each dorsal nerve anastomoses with the gan-
glion  or cord of the sympathetic, after the manner described in
the account of the latter nerve**

  There  are  some  differences  between  the thoracic nerves in
their manner of distribution,

  *  It is observed in pluritis, that there is a deposit of lymph, mixed with the
cellular adipose matter surrounding the  sympathetic, its costal branches and the
subcostal nerves, until the latter get between the intercostal  muscles. This in-
flamed state must, no doubt, produce particular nervous phenomena; as pain,
difficulty of respiration,-and derangement of the functions of the abdominal
viscera. 
502
NERVOUS SYSTEM.
  The anterior fasciculus of the first, as mentioned, forms the
lower part of the  axillary plexus  by joining itself to the se-
venth cervical.  It sends  out, however, a subcostal branch
which goes along  the  inferior  face of the first rib, supplying
the intercostal muscles and having the  general  distribution al-
luded to.
  The Second Subcostal Branch, besides the common distribu-
tion, detaches a.fasciculus, which, penetrating between the ribs,
gets  into the axilla, and is augmented by a  branch from the
internal cutaneous  nerve of the upper  extremity.   It then de-
scends along the internal posterior face of the arm to the elbow,
and in this course detaches several  fine filaments to the integu-
ments.
  The Third  Subcostal  Branch in like  manner detaches an
axillary fasciculus  which goes to the  inferior part of the  arm-
pit, to the  integuments of which, and to those on the internal
face of  the arm, it is distributed.   It does not descend quite so
low as the  preceding.   These two nerves are called Intercosto-
Humeral, and from their origin and  course, are  supposed to
account for the numbness of the arm, in cases of angina pec-
toris.
  The Fourth, Fifth, Sixth, and Seventh Subcostal Branches
of the Dorsal or Thoracic Nerves, about the middle of the ribs
to which they respectively belong, are  all  divided into two
branches.  One of them, which is properly speaking  the in-
tercostal, continues in the intercostal space, giving filaments to
its muscles and to  the triangularis  sterni; it then emerges near
the sternum to terminate  upon the great pectoral muscle, the
mamma, and the integuments of the front of the thorax.  The
other branch is the external pectoral:  it extricates  itself earlier
from the intercostal space, and  is distributed upon the muscles
and  the integuments on the side of the thorax.
  The remaining  subcostal branches,  to the  eleventh  inclu-
sively,  have very much  the  same  principle  of  distribution.
Their intercostal  fasciculi, having reached  the anterior ends
of the intercostal spaces, pass on to the abdominal parietes, be-
tween the  transversalis muscle  and the internal oblique, to both
of which they give filaments.   They reach the  external margin
of the rectus abdominis muscle, and then divide into filaments,
some of which go to this muscle, others pierce  the fore part of 
ABDOMINAL SPINAL NERVES.
503
its sheath and are ramified upon the integuments of the front of
the abdomen.
  The Twelfth Subcostal Branch of the Dorsal Nerves, sends
first a branch downwards, which joins with the first lumbar
nerve.  It  then  crosses in  front of  the quadratus  lumborum
muscle, to which it gives filaments as well  as to the adjoining
portion of  the diaphragm.    It  afterwards divides  into two
branches, the superior of which goes for some distance between
the two oblique muscles of the abdomen,  detaching filaments
to them, and finally terminates on the integuments  of the ab-
domen :  the other  branch goes between  the transversalis and
the internal oblique, and is extended to the lower part  of the
rectus, and to the  pyramidalis muscle, to all of which it distri-
butes filaments.
         SECT. III.--OF THE ABDOMINAL SPINAL NF.RVES.

  There are five lumbar, and five sometimes six sacral nerves
on each side; the first of them passes out of the intervertebral
foramen, between the first and the second lumbar vertebra; and
the remaining  lumbar  and sacral nerves  go, successively,
through the foramina in  the loins and in the sacrum.
  The anterior fasciculi of these nerves form  a plexus which
extends from the upper part of the loins to the lower part of
the sacrum;" it  is designated under the  general  term of Plexus
Cruralis.  The posterior fasciculi are much smaller.  Those of
the loins go backwards  between the  transverse processes, and
are distributed upon the sacro-lumbalis, the longissimus dorsi,
the multifidus spinas, and the corresponding integuments.  The
posterior fasciculi of the sacral nerves  are  not  so large, gene-
rally, as those of the lumbar: they get out through the foramina,
on the posterior face of  the sacrum, are distributed  to the same
muscles; to the origin of the glutasus magnus,  and to  the inte-
guments of the sacrum,  and of the adjoining portion of the but-
tocks.
   The Plexus Cruralis,  for the purpose of description,  has been
divided by anatomists into the Plexus Lumbalis, formed by the
four superior lumbar nerves, and the Plexus Ischiadicus, formed
by the last lumbar and  the sacral nerves. 
 504                  NERVOUS SYSTEM.

   The Lumbar Plexus (Plexus  Lumbdlis) is concealed by the
 psoas magnus muscle, and is placed between it, the lumbar ver-
 tebras, and the quadratus lumborum: frequently the roots of the
 nerves forming this plexus penetrate through the substance of
 the psoas magnus, and form their  unions in it.  The plexus is
 narrow and pointed above, where  it  commences by the fasci-
 culus of the last dorsal nerve joining the first lumbar; but it in-
 creases continually  afterwards in breadth, owing to the nerves
 composing it, successively anastomosing farther and farther from
 the spinal column.  From  this  plexus proceed three principal
 trunks: the upper one  the Anterior  Crural (Cruralis Anterior) is
 of considerable size;  and goes  to  the skin  and the muscles on
 the front of  the lower extremity; the middle, called obturator
 (Nervus Obturatorius,) is not so large as the preceding, and goes
 through the  obturator  foramen to the  adductor muscles of the
 thigh; the inferior, formed by the whole of the fifth and a fasci-
 culus from the fourth  lumbar nerve, joins the upper part of the
 sciatic plexus in the pelvis.  Besides these, there are several
 branches of smaller  size and of less importance, proceeding from
 the lumbar plexus.
  The Abdomino-Crural Branches, according to Bichat, are
 most commonly three  in number, and come  from the two upper
 lumbar nerves. The first of them goes obliquely downwards and
 outwards, in front of the quadratus lumborum, to  the posterior
 part of the  spine of the ilium, and runs for a short distance
 along the crista of the bone: it gives filaments to the iliacus in-
 ternus, and to the abdominal muscles, where they border on this
part of the  bone.   Some of the filaments  become cutaneous,
 but the main trunk  of the nerve reaches  the anterior superior
spinous process, by  going between  the transversalis and the in-
ternal oblique muscle; it  then follows the inguinal arch to the
 external ring, through which it'passes, and is distributed in fila-
ments  upon the groin, the pubis, and the scrotum.  The second
or middle branch arises from the plexus near the preceding; it
descends along the  external margin of  the  psoas magnus, and
crosses the iliacus internus, covered by the  peritoneum;  near
the anterior  superior spinous process, it  gets between the lower
margins of the abdominal muscles,  and is distributed upon them
there:  some of its ramifications get  also through  the external
ring, and  may be traced to the scrotum.  The  third, or the 
ABDOMINAL SPINAL" NERVES.
505
inferior branch, arises from the plexus  still lower down, and,
after  having traversed the front of the iliacus  internus, it
emerges from the pelvis beneath  Poupart's ligament, near the
anterior superior spinous process; it then divides into filaments
which penetrate to the skin through the femoral fascia, and are
distributed along the external anterior face of  the thigh.
  The Spermaticus Externus arises from the upper part of the
plexus, by a fasciculus from  the  first lumbar  nerve, which is
increased  by one from the second lumbar.  It descends at first
in the body of the psoas magnus  muscle and then in front of
it: it  crosses the iliacus internus, somewhat above  Poupart's
Ligament, by directing its course  towards the anterior superior
spinous process of  the ilium.   Here, it  involves itself in the
edge  of the abdominal muscles, and goes on the posterior face
of Poupart's Ligament; at the  internal abdominal ring it joins
the spermatic chord of the male, or the round ligament of the
uterus of  the female.  In the first case, it is distributed to the
spermatic chord and scrotum; in the second, to the labium ex-
ternum and mons veneris.
  The Cutaneus Externus arises from the lumbar plexus tjelow
the external spermatic.   It passes across the  iliacus internus
towards  the anterior superior  spinous  process, about an inch
below the  spermaticus externus, and crosses  the latter nerve
just at that process.   Emerging from the abdomen, by  pene-
trating the commencement of Poupart's Ligament, it is distri-
buted in several branches to the integuments of the vastus ex-
ternus muscle, and along the  edge of the rectus femoris: one
of the latter extends to the patella.

  The Cutaneus Medius is detached from the anterior  crural, an
inch  or so  above  Poupart's  Ligament.  It arises among the
cluster of branches, which come off there to be distributed to
the iliacus internus muscle, and to the muscles  of the thigh.  It
appears, superficially, on the thigh, for the first time, by  pene-
trating the sartorius muscle, about the internal edge of the rec-
tus femoris;  it descends then along the same edge of the  latter
muscle, and is distributed to  its integuments.   It does  not de-
scend so low as the external cutaneous.
  The Cutaneus Anterior arises, also, from the anterior crural
nerve.  It is on the inner side of the cutaneus medius, emerges
  Vol. II.—44 
506
NERVOUS SYSTEM.
from  the fascia of the thigh, and crosses the  sartorius muscle
two or three  inches below the cutaneus medius.  It is distri-
buted on  the  integuments of the vastus  internus muscle, and
some of its branches extend to the internal edge of the patella.

  The Cutaneus Internus arises from the anterior crural nerve,
among the same cluster, above Poupart's Ligament. It divides
into four or five branches of different lengths, and is distributed
to the integuments of the adductor muscles, and along the inner
front side of the thigh. One branch observes very much the
course of the tendon of the  adductor magnus, and reaches as
far  down as the inner side of the knee.

  The Anterior Crural (Cruralis Anterior) arises from the mid-
dle  of the lumbar plexus: at first, it is  beneath the psoas magnus
muscle; it then gets to its outside, and passes from the  abdo-
men, under Poupart's  Ligament, about half an inch from the
outside of the  femoral artery. Before it reaches Poupart's Li-
gament, it gives off a cluster  of nerves, several of which go to
the iliacus internus muscle;  others form  the superficial or cu-
taneous nerves of the thigh  just mentioned; and  others, the
deep-seated or muscular branches, which supply the adductor
muscles, the four extensors,  the  pectineus,  the sartorius,  and
the  gracilis.

  One of  the branches of  the anterior  crural nerve is seen to
accompany the femoral artery,  till the artery penetrates the
adductor magnus;  it then runs along the front margin of the
tendon of  the adductors in a theca formed by this  tendon and
the  origin of the vastus internus.  The nerve alluded to is the
Saphenus; it passes afterwards between the internal condyle
of the  os  femoris and  the sartorius  muscle, attaches itself to
the  saphena vein, and is distributed to  the integuments of the
inner  side of the  leg, and of the upper  internal parts of the
foot.
  The Obturator (Nervus Obluratorius) is  derived from  the mid-
dle  of the lumbar plexus, also;  and has very much the  same
position, in regard to the psoas magnus, as  the anterior crural
nerve.   It descends into  the pelvis from beneath the psoas
magnus, near the sacro-iliac  articulation; and passes forwards
and downwards to the obturator foramen; having  got through 
                   ABDOMINAL SPINAL NERVES.                507

which,  it divides into an  anterior and posterior branch.  The
first is distributed to the head of the adductor longus and bre-
vis, and to the gracilis and integuments. The second terminates
in the obturator externus, and the adductor magnus.

   The Sciatic Plexus (Plexus Ischiadicus) is formed by the union
of the last lumbar with the four  upper sacral nerves; the last
lumbar, before it joins the plexus, receiving  the branch of the
fourth lumbar nerve, which is left after the lumbar  plexus  is
formed.   This plexus is situated at the  side of the rectum be-
fore the pyriformis muscle.
   The  volume of the posterior branches of  the  Sacral Nerves
increases till the fourth; but the fifth and the  sixth are much
smaller, in fact  only fibrillas.
   The anterior branches of the sacral nerves  are much larger
than the posterior.  The four first communicate with the sacral
ganglions of the great  sympathetic,  besides forming the ischi-
atic plexus.   They assist the sympathetic,  to form the hypo-
gastric  plexus.  The fifth, and the sixth, when  it exists, are dis-
tributed to the coccygeus, sphincter, and levator ani.*
   The following small branches go from the Sciatic Plexusf
   a. Nervi Glutei: one passes through the upper  part of the
sciatic notch along with the artery, to the glutasus medius  and
minimus;  another below the pyriformis muscle  to  the glutasus
magnus.
   b. Nervus Pudendalis Longus Inferior, passes under  the tu-
ber of the ischium to the glutasus magnus;  perineal muscles;
urethra and integuments of the penis and scrotum in men;  and
to the inferior parts of  the labium externum in women.
   c.  Ramus  Femoralis Cutaneus Posterior.   This  nerve  is
placed between the integuments of the thigh  and the muscles
which arise from the tuberosity of the ischium.  It  sends many-
branches,  successively, to the  skin  on the  back of the thigh;
one of  its branches, longer  than the others, goes down to the
   * This is only given as the most frequent arrangement of the sciatic plexus,
and of the branches of nerves which proceed from it;  other arrangements will
often be met with in the cavity of the pelvis, in which not so many sacral nerves
are sent to the plexus ischiadicus, and the several branches proceeding from it de-
part in a different manner.
   + They sometimes come from a common trunk, called, in such case, the  Small
Sciatic. 
508
NERVOUS SYSTEM.
ham, and there divides into several filaments, which are distri-
buted to the integuments on the back of the leg.

  The Nervus Pudendalis Longus  Superior  comes  from the
third and fourth sacral.   It goes in  company with the internal
pudic artery between the sacro-sciatic ligaments, and then di-
vides into two branches; the  inferior is distributed to the inte-
guments and  muscles of the perineum, to the urethra  and scro-
tum; the superior passing along the ramus  of the ischium and
pubes with the trunk of the internal pudic artery, is distributed
to the obturator internus, accelerator urinse, urethra, and after-
wards, getting between  the  symphysis of  the  pubes and the
penis, terminates on its integuments and the glans penis.

  The Nervus Ischiadicus, or the Great Sciatic, is  the com-
mon trunk, formed from  the sciatic plexus?  it is much the
largest nerve in  the body, and passes from the  pelvis between
the  pyriformis and the geminus superior.  It crosses, vertical-
ly, the small rojtator  muscles  of the thigh, being concealed by
the  inferior edge of the  glutasus magnus; it is there about half-
way between the tuberosity of the ischium and the trochanter
major.  Thence it descends on the back of the  adductor mag-
nus, at the outer edge of the long head of the biceps flexor cru-
ris.   About half way down the thigh, sometimes a little lower,
the  Sciatic  Nerve divides into the Popliteal, or Posterior Tibi-
al, and Peroneal.   Occasionally this division takes place as high
as the exit of  the  nerve from the pelvis; but in this  case the
fasciculi are parallel  with each other as far as the middle of the
thigh.   From the trochanter minor to its usual place of division,
this nerve is parallel  with, and on the back  of the thigh bone;
afterwards  the two branches  begin to diverge.   The  popliteal
nerve continues straight downwards to  the back and middle
of the knee-joint, and to  the interstice between the heads of the
gastrocnemius muscle; whereas the peroneal nerve goes along
the  inner posterior edge of the biceps flexor cruris, and passes
between its tendinous insertion and the external head of the
gastrocnemius muscle.
  In this course, the  following branches are sent from the sci-
atic—Twigs to the  little rotator muscles of  the thigh.—The
Cutaneus Internus Superior, which  arises near  the upper part
of the thigh, and is distributed to the skin of tbe corresponding 
ABDOMINAL SPINAL NERVES.
509
part.—The Cutaneus Internus Inferior, which arises just below
the last, and, descending upon the inner head of the gastrocne-
mius, is distributed to the  integuments  of the calf of the leg.—
A large trunk, and sometimes, instead of it, distinct branches
which go to the Adductor Magnus, Semi-membranosus, Biceps
and Semi-tendinosus.

   The Peroneal Nerve  (Nei-vus Peroneus) divides at the head
of  the fibula into  two  branches, the  Peroneus Externus and
the Tibialis  Anterior; but, before this division, it sends a  small
branch to the external parts of the knee-joint, and two cutane-
ous branches  called Peroneo-Cutaneous.  The Internal Pero-
neo-Cutaneous descends behind the external  head of the gas-
trocnemius,  and, at the bottom of the leg, is united to a division
of the posterior tibial called the External Saphenus, or Commu-
nicans Tibias.  The External Peroneo-Cutaneous is distributed
to the skin, along the fibula.

   The External Peroneal  Nerve (Peroneus  Externus) gets be-
tween the head of the peroneus longus and the fibula, then be-
tween the peroneus longus and  the extensor  longus  digitorum,
leaving filaments to these  several muscles as it goes along.   It
descends, at the outer edge of the  last muscle, to the inferior
third of the leg, giving  out, in- the mean time, many muscular
branches.  Here it  penetrates  the aponeurosis, and  divides
i nto cutaneous branches, which supply the lower  part  of the
leg, and the upper surface of the foot and toes.  This nerve is
called, by the French, the Musculo-Cutaneus of the leg.
   The Anterior Tibial Nerve (Tibialis Anterior) gets obliquely
between the fibula, the  peroneus longus, and the extensor lon-
gus digitorum, to the front of the interosseous ligament, where
it accompanies the anterior tibial artery.  It  passes, with the
artery,  under the annular  ligament  of the  ankle, and  has its
terminating  filaments going to the muscles and integuments of
the upper surface of the foot, as far as the end of the first two
toes.   One of its branches sinks down with the anterior tibial
artery to the sole of the foot.  High up in the  leg it sends fila-
ments to the knee-joint, and, in  its  course downwards, it fur-
nishes the muscle on the front of the leg.
   The Posterior Tibial, or  Popliteal  Nerve, (Nervus  Popli-
                            44* 
 510                   NERVOUS SYSTEM.

 teus,) having the direction mentioned, is placed  between tha
 skin and the  popliteal vein.   It gets between the heads of the
 gastrocnemius muscle, and perforates the origin of the soleus;
 going with the posterior tibial artery, between this muscle and
 the flexor longus digitorum,, to the bottom of the leg.  It gives
 off the following branches:—

   a. The External Saphenus, (Saphenus Externus, or Com-
 municans Tibia?,) which arises above the knee-joint, and, de-
 scending between the  skin and the  gastrocnemius, turns out-
 wardly, and anastomoses with the cutaneous branch, alluded to,
 of the peroneal nerve.  The common trunk, thus formed, passes
 behind the external  ankle, along  the external margin  of the
 foot, and terminates on the outer toes, having given off a great
 number  of cutaneous branches.
   b. Branches to the heads of the gastrocnemius,  soleus, plan-
 taris, and popliteus.
   c.  Branches to the flexor longus digitorum, tibialis posticus,
 and to the flexor longus pollicis pedis.
   d.  A branch through the interosseous ligament, above, to the
 tibialis anticus,
   e.  At  the inferior part of the leg many cutaneous filaments,
 one  of which gets to the sole of the foot.

   The Posterior Tibial Nerve, having given off these branches,
 divides, in the hollow of the os calcis, into the Internal and  the
 External Plantar Nerve.
   The Internal  Plantar (Plantaris Internus) proceeds  along-
 side  of the tendon of the flexor longus muscle of the great toe,
 and the flexor longus digitorum, and gives filaments to the con-
 tiguous muscles.   It then divides in  such a way as to furnish
 the two sides of the first three toes and the internal side of the
fourth.
  The External Plantar (Plantaris  Externus) proceeds with
the artery of the same name to the outer edge of the foot, be-
tween the flexor brevis  digitorum  and the flexor accessories.
It is distributed to the two sides of the little toe, and to the ex-
ternal side of the fourth  toe.  One branch penetrates to the  in-
terosseous muscles and  to  the transversalis pedis.  A branch
of considerable size is  also detached, near  the  heel, to the
muscles and integuments connected with  the os calcis. 
INDEX  TO  VOL..   II.
                                                         Page
Abdomen, generally,           ....         5
          General Situation of the Viscera of,            -      7
          Veins of,           -  ,            -       -       263
Abdominal Aorta, Branches of,    -      -      -      -    222
Absorbent Glands of the Abdomen,     -       -       -       302
                      Head and Neck,  -      -      -    291
                      Lower Extremity,    -       -       295
                      Upper Extremity, -      -      -    293
                      Thorax,       ...       308
Absorbents of the Pelvis,   -----    296
                 Head and Neck,     ...       289
                 Upper Extremities, and the Contiguous
                  Parts of the Trunk of  the Body,      -    291
                 Inferior Extremities, and the Contiguous
                   Parts of the Trunk of the Body,      -    293
                 Organs  of Digestion,  -                      298
                 Parietes of the Trunk,   -      -      -    306
                 Viscera of the Thorax,       -       -       303
Absorbent System, Special Anatomy of,    -      -      -    289
                 General Anatomy of,           0  -       280
Accelerator Urinas, -       -      -      -      -      -    101
Aorta, and the Branches from its Curvature,    -       -       195
Aqueous Humour, -       -      -      -      -      -431
Aqueducts of Ear,      -----       448
Arachnoidea,      ------    345
Areola,         -----               123
Arcus Sublimis,    -       -      -      -      -      -    219
Arteries,      -      -       -       -       *       "       *95
        Texture of,       -      -      -      -      -    165
Arteria Aorta Thoracica, Branches of,   -       -       -       220
       ad Cutem Abdominis,      -                         238
       Alveolaris Superior,  /  -       -       -       -       206
       Anastomotica, (Arm,)       -       -       -       -    215
       Anastomotica, (Thigh,) -                             240
       Articularis Superior Interna, Thigh, -       -       -    241
       Articularis Superior Externa,  "       -        -       241
       Articularis Media,       -     "           -       -    242
       Axillaris,       -       -       -       -       *       213 
512                          INDEX.

                                                             Page
Arteria Articularis Inferior Externa, Thigh,     -       -        242
       Articularis Inferior Interna,  -                           242
       Auricularis Posterior,    -                              203
       Basilaris,    """""."    ^^
       Brachialis,       -       -      -       -       "        214
       Buccalis,    ------    206
       Callosa,         ....       -        383
       Carotis Primitiva,.   -----    197
       Carotis Interna,  -       -      -       "       -        198
       Carotis Externa,    -       -       -       -        -    199
       Cavernosa Profunda Penis,     -                       235
       Coeliaca,    ------    222
       Cerebri Posterior,       ...       -        3^5
       Cervicalis Posterior,        -       -       -        -    210
       Choroidea,      -----        383
       Ciliaris,     -       -       -       -       -        410,422
       Circumflexa Anterior of Axillaris,       -       -        213
       Circumflexa Posterior,      -       -       -        -    214
       Circumflexa Externa,   -                              238
       Circumflexa Interna,        ....    239
       Circumflexa Ilii,        -       -       -                236
       Colica Sinistra Superior,    -                           226
       Colica Sinistra Media,  -      -       -       -        226
       Colica Sinistra Inferior,     -                           227
       Communicans Posterior of Brain,       -       -        383
       Dentalis Inferior,   -----    205
       Dorsalis Carpi,  -       -       -       -       -        216
       Dorsalis Hallucis,   -----    245
       Dorsalis Manus,        -      -       -        -        219
       Epigastrica, ------    236
       Facialis,-              ....               201
       Femoralis,  ------    237
       Frontalis,       -       -       -       -       -         412
       Gastrocnemea,      -----     243
       Gastriea,        -       -       -       -       -        222
       Gastrica Dextra,     -       -       -       -       -     223
       Gastriea Sinistra,        -                               224
       Glutea,     ------     233
       Haemorrhoidea Inferior Externa,        -       -         234
       Haemorrhoidea Media,      -                           232
       Haemorrhoidea Superior Interna,        -       -         227
       Hepatica,   ------     223
       lliaca Interna,   -----         230
       lliaca Externa,       -                                   235
       Ilio-Lumbaris,   -                                       230
       Innominata,        -       -        -       -       -     197
       Intercostalis Superior,   -                               209
       Interossea Anterior,         -       -       -       -     218
       Interossea Posterior,     -       -      -       -        218
       Infra-Orbitalis,       -----     207
       Inferior Cerebelli,       -       .       _.                395 
INDEX.
513
                                                            Page
Arteria Ischiadica,       -----        233
       Lachrymalis,       -----     409
       Lingualis,       -                                      200
       Magna Pollicis,     -        -       -      -       -     217
       Mammaria Externa,     -              -       -        212
       Mammaria Interna,  -----     209
       Maxillaris Interna,      -                              205
       Malleolaris Externa,         -                           244
       Malleolaris Interna,      ...       -        244
       Mesenterica  Inferior,        -       -      -       -     226
       Mesenterica  Superior,   -                              224
       Metatarsea,  ------     244
       Meningea Parva,       -                              205
       Meningea Magna,   -----     205
       Muscularis of Orbit,     -       -       -       -        411
       Nutritia, Brachialis, -       -       -      -       -     215
       Nasalis,        -       -       -       -       -        411
       Obturatoria,        ' -       -       -      -       -     231
       Occipitalis,      -                                      202
       (Ethmoidea,        -----     410
       Palatina Superior,       ...       -        207
       Palmaris Profunda,   -       -        -      -       -217
       Palpebralis,      -       -       -       -       -        411
       Peronea,     ------     246
       Pedicea,        -----        245
       Perinea,    ------     235
       Pharyngea Inferior,     -                              202
       Pharyngea Superior,        ...       -     207
       Plantaris Externa,      -                              247
       Plantaris Interna,   -       -       -      -       -     247
       Poplitea,        -----        241
       Profunda Femoris,   -----     238
       Profunda Major Humeri,        ...        214
       Profunda Minor,   "       -       -       -       -     215
       Pterygoidea,    -                                      206
       Pudica Interna,      -----     234
       Radialis,        -        -       -       -       -        216
       Radialis Indicis,     -       -       -       -       -     217
       Recurrens Radialis,      -       -       -       -        216
       Recurrens Ulnaris,   -       -        -       -       -218
       Sacra Media,    -----        229
       Scapularis,   ------     213
       Spheno-Palatina,        -                              207
       Superior Scapulae,  -----     211
       Superficialis Volae,       -       -       -      -        216
       Superior Cerebelli,  -       -        -      -       -     385
       Subclaviana,    -----        207
       Splenica,    -.....224
       Tarsea, ------        244
       Temporalis, -       -       -       -       -       "    204
       Thyroidea Inferior,             ;       "               209 
514
INDEX.
                                                            Page
                                                             199
Arteria Thyroidea Superior,        -              "            gl2
      Thoracica Longa,      -                               2^2
      Thoracica Acromialis,       -
      Thoracica Axillaris,    -       -                       204
      Transversalis Faciei,        -       -                      ^
      Temporalis Media,     -       -                         _
      Temporalis Profunda,       -                           *"
      Thoracica Superior,    -       -      "                "Z
      Tibialis Anterior,   -                                   *™
      Tibialis Postica,       -                               f™
      Tibialis Recurrens,  -       -       -       "            ~™
      Tympanica,           -  .     -
      Ulnaris,     -      -       -      - -       "       '     t£L
      Uterina,         -      -       -      -                Z6Z
      Vertebralis, -----       208, 384
Arteriae  Bronchiales,    -      -       -       -               f^~
       Capsulares, -----            227
       Emulgentes,    -                                     .a
       Gastricae Breves,   -                                  2^4
       Gemellae,       -      -       -       -      -        243
       Intercostales Inferiores Aorticae,     -              -    221
       Iliacae  Primitivae,       -                               230
       Lumbares,  -      -       -       -       -       "    ^28
       Mediastinales Posteriores,       -       -      -        221
       (Esophageal,       -                                  ^^
       Pancreaticae Mediae et Sinistrae,  -                       224
       Phrenicae,  -      -       -       -       -       "    ^22
       Profundae Perforantes Femoris,  -                       239
       Pudendae Externae, -----    238
       Sacrae  Laterales,     .  -       -       -      -        231
       Spermaticae,       -----    228
       Vesicales,      -----        232
 Aryteno-Epiglottideus,    -       -        -       -       -     131
 Arytenoid Cartilages,   -      -       -        -       -         127
 x^rytenoideus  Obliquus,    -----     130
              Transversus,     -       -        -       -         131
 Auditory Nerve,   ------     450
 Axillary Artery, Branches of,  -       -        -       -         211
 Biliary Ducts,      ------      63
 Bile,.......63
 Bladder,.......78
         Structure of,                                           79
 Blood,      -       -       - -     -       -       -       -     175
        Coagulating Lymph of,  -       -       ■•       -         179
        Red Globules of,   -      -       •       -       -     180
        Serum of,                                             177
 Bones of Tympanum,     -      -       -      -       -     441
 Brachial Artery, Branches of,   -       -       -       -        214
 Brain,       -.....-     338
 Broad Ligaments of the Uterus, -       -       -       -         115 
INDEX.                         515
Brain, Veins of,    -----      .    386

Carotids, Branches of,  -       -      -      -       -        198
Capillaries, -      -      -       -       -       -      -160
Capsule of Glisson,    -       -      -      -       -         13
Caul, Situation of,  -      -       -      - -       -      -      8
Ccecum,        .-..._         37
Cerebellum,       -      -       -       -       -      -    354
Cerebrum,    -_....        357
Chambers of Eye,  -      -       -       -       -      -    432
Choroidea,     -       -       ..      -      . ^     .        417
Chorda Tympani,  ------    451
Chylopoietic Viscera,   -       -      -      -       -         22
                    Assistant,    -       ...     56
Cilia,  -       -       -       -             .       .        399
Circulation of the Foetus, Peculiarities of,   -       -      -    270
                       Peculiarities of, connected with
                          its Nourishment,      -      -    275
Circulatory System,    -       -       -       -       -        153
                  General Anatomy of,   -       -      -    153
                   Consideration  on General Anatomy
                      of,  -       -       -       -           153
                  Special Anatomy of,       -       -        183
Clitoris,    -      -       - •      -       -       -      -    107
Coccygeus, Muscle,    -----        103
Cochlea,    -      -       ...       -       -      -    446
Colon, -              .....         38
Commissura Anterior,     -       -       -       -      -    371
Conjunctiva,    ...             -               400
Corona Glandis,   ------     86
Cornea,       -       -              ...        415
Corpus, Callosum, ------    363
       Cavernosum,   -----         87
       Ciliare,    ......    417
       Dentatum,-    .....        356
       Fimbriatum,        -       -       -       -      -118
       Spongiosum,   -----         88
       Spongiosum Vaginae,       -       -       -      -    111
Corpora Striata,        -----        362
Crura Cerebri,     ------    359
Couper's Glands,       .....         92
Coronary Arteries,  -----        192, 196
          Veins,       -       -      -      -       -        193   "
Cremaster Muscle,  -        ...       -      -     95
Cricoid Cartilage,       -       -      -      -       -        126
Crico-Arytenoideus Posticus,       -       -       -      -    130
                  Lateralis,   -      -      -       -        130
Crico-Thyroideus,  -       -       -       -       -      -130

Dartos Muscle,  ------         94
Ductus Ejaculatorius,       -       -       -       -      -     91 
 516                         INDEX.

                                                            Page
 Ductus Lactiferi,   -----            1*2
 Duodenum,    -       -       -       -       "                Jj2
 Dura Mater,       ------     ddb
            Sinuses of,  -       -       -       -       -         339
 Ductus Wirsungii,  ------      69

 Ear,.......433
 Eminentiae Mammillares,  ■ -       -       -       -      -     360
           Olivares,    -----         350
 Epididymis,       -      -       -       -       -      -      97
 Epiglottis,     -              -       -       -       -         127
 Erector Clitoridis, * -       -       -       -       -      -     108
        Penis,  ------         100
 Eustachian Valve,  -      -       -       -       -      -     186
           Tube,      -      -       -        -                440
 External Iliac Artery, Branches of,  -                           235
 Eye,......-         397
 Eyeball,    -----       -      -     413
 Eyelids,......398

 Fallopian Tubes,   -       -       -      -       -       -     117
 Foetus, Peculiarities of, arising from want of Respiration,        271
 Fornix,   -------     364
 Fossa Navicularis,    -----         89
      Ovalis,      ------      186
 Fourchette,    -      -       -       -       -      -        107
 Fourth Ventricle,  -       -       -      -       -       -     372
 Fraenum Penis,       -       -       -       -      -         86
 Frontal Nerve,    ------     457
 Fundamental Portion of Cerebellum,  -       -      -        356

 Ganglion Cavernous,       -----     478
         Cervical,     -                                     479
         Lumbar,  ------     487
         Lenticular,    -      -       -       -      -        454
         Spheno-Palatine,  -       -      -       -            396
         Sacral,       -----        488
         Thoracic, ------     483
 Gall Bladder,   -----                61
 Glandulae Odoriferae Tysonii,       ....      86
         Pacchioni,    -----        347
         Palbebrarum,    -       -      -       -       -     401
 Glandula Pituitaria,     -----        36O
         Pinealis,  ------     366
Globus Major,  ------         97
       Minor,     ------      97
 Glands of Brunner,     -      -      -       -      -         31
         Peyer,   ------      31
Head and Neck, Veins of,      -       -       -      -        249
Heart,      -------     183
      Right Auricle of,        -       -       -      .         185
      Right Ventricle of,  -       -      -      -       -     187 
INDEX.
517
                                                          Page
Heart, Left Auricle of,                                       189
      Left Ventricle of,       ....        190
      Blood Vessels of,    -----    192
      Texture of,     ....       -        191
Hymen,    -       -       -,     -       -      -      -111

Ileo-Colic Valve,       -----         37
Ileum,     -                             -      -      -     33
Incus, -       -       -                                    441
Internal Iliac  Artery, Branches of,  -       -      -      -    230
Inguinal Glands,       -      -      -              -        295
Intestinal Canal,    ------     28
Intestine, Small,       ....       -         34
Large,
34
        Small, Situation of*                                    8
        Large, Situation of,      , -       -       -       -       8
Iris,   -......421

Jejunum,   ------             33

Kidneys,       ....      -                71
         Situation of,      ....       -       9
         Minute Structure of,  -       -      -      -         72

Labia Interna,     -      -      -       -       -       -108
      Externa,  -      -      -       -      -      -        107
Labyrinth, ------            444
Lachrymal Apparatus,  -----        403
          Caruncle,       -----     405
          Ducts,.....404
          Gland,......404
          Nerve,      -----        457
          Sac,......406
Larynx,        ------        125
Lateral Ventricles, ------     368
Levator Ani,   -      -      -       -      -      -        103
Lens,.......428
Ligamentum Ciliare,    -----        417
             Denticulatum, -----     336
             Palpebrale Internum,     -      -      -        398
                       Externum,        *      -      -    399
 Liver,  -------          56
      Organization of,      -      -      "      "      -      58
      Situation of,                                             ?
 Lower Extremity, Veins of,        ...      -    261
 Lungs, -----                       J43
       Texture of,  ------     144
 Lymphatic Glands,     -      -       -       -      "        286

 Mesocolon,  -
 Malleus,       -                                             ._.
 Meatus Externus,   -       -       -       -      -
    Voe.  II.—45 
 518                         INDEX.

                                                           Page
 Mediastinum Anterior, -      -      -       -       -        149
             Posterior,     -       -      -      -       -     149
             Superior, -      -      -       -       ••        150
 Medulla Oblongata,        -              -      -       -     349
         Spinalis, Nerves of,   -       -       -       -    327, 489
 Membrana Pupillaris,      ...      -       -     432
           Tympani,  -----        438
 Membranous Labyrinth,    -----     447
 Mesentery,    _----.         33
 Mitral Valve,       -      -       -      -      -       -     190
 Mons Veneris,  -      -      -      -       -       -        106
 Mucous Glands, and Apparatus,                                 90
        Membranes, General Anatomy of,      -       -         50
 Musculus Anterior Auriculae,       ....     433
          Antitragicus, -----         437
          Attollens Auriculae,       -                          437
          Helicis, Major et Minor,     -                        436
          Laxator Tympani,       ....     442
          Levator,  Palpebrae Superioris,       -       -         401
          Obliquus Oculi Superior,  -      -       -       .     402
          Obliquus Oculi Inferior,     ...        403
          Rectus Oculi Superior,    -                           402
          Rectus Oculi Externus,      ...         402
          Rectus Oculi Inferior,    -                          402
          Rectus Oculi Internus,       -                       402
          Retrahens Auriculae,      -       -       .      .    437
          Stapedius,    -                                     443
          Tensor Tarsi,   -                                   497
          Tensor Tympani,    -                               443
          Tragicus,        -----     437
          Transversus Auriculae,       ...        437
Mucous Coat, minute Anatomy of,  -       -       -       -      41


Nervous System,   -      -       -       -       .       -313
        General Anatomy  of,   -       -       -       .         313
                                                            456
                                                            373
                                                           450
                                                            504
Nasal Nerve,
Nerves of Encephalon,  -
          Ear,
Nervus Abdomino Cruralis,
      Abdominal Spinal,
Accessorius,    -      ...       .       -   381  4fiQ
Auditorius, -       -       .       ,      .           ' „7g
Auricularis,     ....                .„„
Cervicalis,  -       -      .       -      -   *   -     490
Circumflexus,   -                                     J™
Cruralis Anterior,   -                                  t^
Cutaneus Externus,    ...                V^Z
Cutaneus Internus,         -       .      .            *jjJL
Cutaneus Femoris Externus,    -       .                SJ
Cutaneus Medius,   -       .       .                   °04
Cutaneus Femoris Internus,     -                       Jn«
                                                     505 
INDEX.
519
                                                           Page
Nervus Cutaneus Anterior,      -       ...      -        504
      Cutaneus Femoris Posterior,        -       -       -    506
      Descendens Noni,       ...      -        468
      Facialis,     -----   379, 450, 465
      Glosso-Pharyngeus,     ....   330, 470
      Glutei,      ------    506
      Hypoglossus,   -----   382, 468
      Infra Maxillaris,     -----    462
      Infra Orbitalis,  -----        458
      Ischiadicus,  ------    507
      Laryngeus Inferior,      ...      -        474
      Laryngeus Superior, -----    473
      Maxillaris Superior,     ...      -        458
      Medianus,    ------    499
      Motor Externus,        ...      -   378, 455
      Motor Oculi,.....376
      Nasalis Internus,        -       -       -      -        395
      Naso-Palatinus,     -----    396
      Obturatorius,    -----        505
      Olfactorius, -----       374, 393
      Opticus,        -----   375, 453
      Patheticus,   ------    376
      Palatums,       -       -       -       -      -        461
      Peroneus,    ------    508
      Petrosus Superficialis,   -                              460
      Petrosus Profundus,        ...       -    461
      Pharyngeus Superior,    -                              473
       Phrenicus,   -----            493
       Plantaris Externus,      -       -       -      -        510
       Plantaris Interims,   -----    509
       Pneumogastricus,       -       -       -      -   381, 472
       Portio Dura,        -----    465
       Portio Mollis,  -----    379, 451
       Popliteus,    ------    509
       Pudendalis Superior,    ...      -        507
       Pudendalis Inferior, -----    506
       Pterygo-Palatinus,      ...      -        460
       Radialis,    -       -      -  •  .  -       -       -    498
       Scapularis,     -----        495
       Saphenus Externus, -----    509
       Spermaticus  Externus,   -       -        -       -        504
       Splanchnicus,       -----    484
       Spiralis,......498
       Subcostales,         -      -       -       "       -    501
       Suboccipital,  -                                     489
       Subscapularis,       -       -       "                  495
       Sympathetica,  -       -      -              "        477
       Trigeminus,         -                             495 500'
       Thoracici,       - .           "                     ' 2£
       Tibialis Anterior,    -                                  °"°
Trochlearis,
454 
520
INDEX.
                                                            Page
  Nervus Ulnaris,    -...--     499
         Vidianus,       -       -       -      -      -   451, 460
  Neurilemma of Nerves,     -       -       -      -       -315
  Nose,  -       -      -             -       -       -         387
       Blood vessels of,      -       -,             -       -     397
       Nerves of,       -                                     393

  Omenta,                                                     13
  Omentum Colicum,  _ -      -      -       -       -          14
  Omentum Gastro Splenicum,       -       -      -       -      15
           Majus, or Gastro Colicum,   -                        13
           Minus, or Hepatico Gastricum,   -      -       -      13
  Ophthalmic  Nerve,     -----        374
  Optic Nerve,      --....    375
  Orbit, Arteries of,                                           409
       Nerves of,   -       -      -      -       -       -    409
       Veins of, -      -       -      -       .       .        412
 Orbiculare, os,     -----       _    442
 Organs of Assimilation,  -----          4
          Generation,      -      -      -       _       -     85
          Generation in the Male,      ...         85
          Generation in the Female,       -       -       -    106
          Respiration,   -       -       -       .      _        125
 Os Tincae, -       -       -      .      .       .       -113
 Ostium Venosum,     -       -       -       .      -   187  190
 Ovaries,    -       -       -      .      .       _       -'ll8

 Pancreas,      -      -       .       .       .      .         go
         Situation of,      -      ....
         Minute Structure of,  -                               gg
 Papilla Mammae,   --....     12q
 Pelvic Fascia,  -      -      .       .       .      „        ,n^
 Penis,     -------      85
 Pericardium,    -              -      „       .       _         ,„.
 Perineal Fascia,   --.-...            jno
 Perineum, Muscles and Fascia of,      -                       ,nn
 Peritoneum,       ...                 "         l™
Pia Mater,      -       -       .      .                       JJ
Pigmentum Nigrum, of Eye,      -                 '        IVa
Pituitary Gland,      ....                      4J8
Pleurae, -
Membrane,      -       .       .           '        JJJ
390
Plexus Brachialis,  -                                         J47,
      Cardiacus,      -                                     fj4
      Choroides,  ---_""        482
      Coeliacus,      ...                  "     370
      Coronarius,  -                                         4°^
      Hepaticus,      ...                  "     486
      Ischiadicus,  -                                         486
      Lumbalis,      .      .                              ^06
      Mesentericus Inferior,       .       .   "                504
      Mesentericus Superior,  -                         "     487
                                           *       -        486 
                             INDEX.                          521

                                                           Page
Plexus Diaphragmaticus,   -      -       -       -       -    485
       Renalis, ------        486
       Solaris,     -       -       -        -       -            48 i
       Splenicus,      -       -       -       -      -        486
Plica Semilunaris, ------    405
Pori Biliarii,    ------         61
Prepuce,   -------86
Primitive Iliac Artery, Branches of,    -       -      -        230
Processus Ciliaris,  ------    418
Prostate Gland, -      -       -       -       -      -         91
Protuberantia Annularis,    -----    353
Pulmonary Artery,     -       -       -       -      -        189

Rectum,    -------     38
Renal Capsules,       -       -       -       -      -         77
               Minute Structure  of,                           77
               Situation of,                                     9
Retina,    -------    423
Round Ligaments of the Uterus,       -       -      -        115

Saceulus Ellipticus,        ^      -       -       -       -    447
         Sphericus,    -       -       -       -      -        447
Sclerotica,  -       -       -      -       -       -       -    414
Scrotum,       -      -       -       -    .   -      -         93
Semicircular Canals,       ...       -       -    445
Seminal Vesicles,      -----         90
Senses,     -------    387
Serous Membranes, generally,  -       -       -      -         10
                   General Anatomy of,   -       -       -     18
Septum Lucidum,      -----        366
Sinuses of Valsalva,        -      -       -       *       -    191
          the Vertebral Column,       -       -      -        257
Sinus Cavernosus,  ------    344
      Circularis,       -       -       -       -      "  .      345
      Lateralis,......343
      Longitudinalis, Inferior,                       "        ;**£
      Longitudinalis,  Superior,"   -       -       -            342
      Occipitalis,      -----        j}J°
      Petrosi,      ------    f44
      Quartus,......Sl6
Scemmering's Foramen,    -                                  Ti
Spermatic Chord,      -                                     -02
Sphincter Ani,      -                                         .,,
         Vaginae,     -                                -    327
Spinal Marrow,    -       -                                 QQq
               Membranes of,  -                              666
               Nerves of,  '      '       ~       '       ~    itl
               Vessels of,      .       -       -      -        dd7
Spleen,    -                                                   8
       Situation of,     -       -
       Intimate Structure of,      -       -.       -       -     oo 
 522                         INDEX.

                                                           Page
 Stapes,.....-                44j
 Stomach,   -------      *&
         Situation of,  -                                       8
 Subclavian Artery, Branches of,    -       -       -       -     207

 Tarsi,  -------        399
 Taenia Striata,      -       -       -       -       -       -     363
 Tela Choroidea,       .....        348
 Testicles,   -------      93
         Minute Structure of,  -                               97
 Thalami Optici,    ------     361
 Third Ventricle,        -----        370
 Thymus Gland,    -       -       -       -       -       -     141
 Thyreo-Arytenoideus, Muscle, -       -       -       -        130
        Epiglottideus,      -       -       -       -       -131
        Hyoideus,     -      -       -       -       -        130
 Thyroid Gland,    -       -       -       -       -       -     139
         Cartilage,     -----        126
 Thoracic Aorta, Descending Branches of,   -       -       -     220
         Ducts,       .....        309
 Trachea,    -------     135
 Transversus Perinei, (Male,)   -       -       -       -        102
                    (Female,)     -       -       -       -     111
 Triangular Ligament of the Urethra,    -       -       -        104
 Tubuli Seminiferi,  ------      97
 Tuber Cinereum,       -      -       -       -       -        361
 Tubercula Quadrigemina,  -       -       -       -       -     367
 Tunica Albuginea,      .....         qq
       Hyaloidea, ------    427
       Vaginalis,      -      -       -       .       .         95
 Tympanum,        ------     438

 Umbilical Artery,       .....        276
         Vein,     ------     275
 Upper Extremity, Nerves of,   -       -       -       -        494
      Veins of,    -----        .    258
 Ureter,         ------         76
Urethra, (Male,)    ------      88
        (Female,)     -       -       .      .       .         10g
 Urinary Organs,   -      -       -       .       .        -      71
 Uterus, and its Appendages,    -       .       .       .        ^12

 Vagina,.......110
Valve of Vieussens,    -                                     3gg
Vasa Arteriarum,   -      -       .       .       .        -169
     Efferentia,       -                                       o«
     ■EvcC-lcly         •      «       m       m                     (~\**j
     Vorticosa,        .....        49n
Vas Deferens,      .....
Vena Azygos,   -
     Axillaris,     ....
     Basilica,   -
 98
256
260
259 
INDEX.
523
Vena Cava Inferior,        -       -      -      .       -     265
     Cava Superior,   -                                     254
     Cephalica,    ------     259
     Choroidea,       -                                     4jg
     Facialis,      -----.     249
     Femoralis,       .....         261
     Hypogastrica,        -----     263
     Hemiazygos,     -                                     256
     lliaca Externa,       -       -      .      .       .     263
     lliaca Interna,    -                                     263
     lliaca Primitiva,      -----     265
     Innominata,      -                                     254
     Intercostalis Superior,        -                           255
     Jugularis Externa,       -      -       .       .         252
     Jugularis Interna,     -----     253
     Lingualis,        -                                     250
     Mammaria Interna,    -----     255
     Maxillaris Interna,       -                              252
     Mediana,      --....     ^gg
     Meseraica Inferior,       ....         269
     Meseraica Superior,   -                                  269
     Occipitalis,       -      -      .       .       .         250
     Ophthalmica,  --....     409
     Palatina Inferior,  -      -      -       -       .         250
     Pharyngea,   ------     250
     Pophtea,  ---...         26I
     Portarum,     ------     268
     Ranina,   ---...         249
     Sacra Media,  ------     266
     Saphena Minor Externa,  -      -       -       .         262
     Saphena Magna Interna,      -                           262
     Splenica,  -----.         268
     Subclavia,    --.-..     260
     Submentalis,     -                           ,__         250
     Temporalis,   -       -       -      -      -       -251
     Temporalis  Superficialis, -      -       -       -         251
     Thyroidea Inferior,    -----     255
     Thyroidea Superior,      ....         250
     Vertebralis,    ------     255
Veins, Texture  of,                                           171
Venae Capsulares,  ----..     268
     Diploicae,        -                                     251
     Emulgentes,  ------     267
      Hepaticae,       -                                     268
     Lumbales,    ------     266
     Phrenicae Inferiores,     -                              268
     Spermaticae,  ------     266
     Ventricles of the Brain,   -       -        -       -         368
Verumontanum,    ------     92
Vesical Triangle,      .....         80
Vestibulum of Vulva,       .....     j09 
524


Vestibulum, Ear,
Vitreous Humour,
Vulva,

Willis, Circle of,
Winslow, Foramen of,
INDEX.
444
426
106

386
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much as possible, " technicality;" and has
given, if he does not  flatter himself too
much, to each disease of which he treats,
its appropriate and designating characters,
with  a  fidelity that will prevent  any  two
being confounded  together, with the best
mode of treating them, that either his own
experience or that of others has suggested.
HORNER'S   SPECIAL   ANATOMY.
  A Treatise  on Special and  General Anatomy.  By W. E.
Bor of Anatomy in  the  University of Pennsylvania, &c. &c.
and much improved.  In two volumes *••*
Horner, M. D., Profes-
Fifth edition,  Revised, 
30
MEDICAL AND SURGICAL BOOKS,
ELLIS'  MEDICAL FORMULARY.
  The Medical Formulary, being a collec-
tion of prescriptions derived from the writ-
ings and practice of many of the most emi-
nent Physicians in America and Europe.
To which is added an appendix, containing
the usual Dietetic preparations and Anti-
dotes for Poisons,  the whole accompanied
with a  few brief Pharmacuetic  and Medi-
cal  observations.  By Benjamin Ellis, M.
D., Fifth edition,  with additions. In one
vol.
  Broussais on Inflammation, 2 vols. 9vo.
  Broussais' Pathology, 1 vol. 8vo.
  Colles' Surgical Anatomy, 1 vol. 8vo.
  Costers' Physiological Practice, 1 vol.
8vo.
  Greys' Chemistry applied to  the Arts,
2 vols,  with numerous plates.
  ELEMENTS  of  PHYSICS,  or
NATURAL  PHILOSOPHY,  GE-
NERAL  and  MEDICAL, explained
independently of TECHNICAL MA-
THEMATICS, and  containing  New
Disquisitions and Practical Suggestions.
By  Neil Arnott, M. D.    In two
volumes,  octavo.
  " Dr. Arnott's work has done for Physics
as much as Locke's  Essays did for  the
science  of  mind."—London University
Magazine.
  " We may venture  to predict that it will
not be surpassed."—Times.
  " Dr. A. has  not done less for Physics
than Blackstone did for the Law."—Morn-
ing Herald.
  "Dr. A. has  made Natural Philosophy
as attractive as  Buffon made Natural His-
tory."—French Critic.
  " A work of the highest class among the
productions of mind."—Courier.
ROGET'S  PHYSIOLOGY   AND   PHRENOLOGY.
OUTLINES   OP   PHYSIOL.OGY;
                            WITH AN
APPENDIX   ON  PHRENOLOGY;
                  BY P.  M.  ROGET., M. D..
Professor of Physiology in the Royal Institute of Great Britian, &c. &c.
           FIRST  AMERICAN  EDITION,
                  Revised, with numerous notes,
                         In one volume, 8vo.
  From the American Preface.—" Of the
the Author's qualifications as a physiological
writer it is  scarcely requisite  to  speak.
The fact of his having been selected to com-
pose the Bridgewater Treatise on  Animal
and Vegetable Physiology, is sufficient evi-
dence of the reputation which he then en-
joyed; and the mode in which he executed
the task amply evinces that his  reputation
rested on a solid basis.
   "The  present volume contains  a  con-
cise, well-written epitome of the present
state of Physiology—human  and compara-
tive—not, as a matter to be  expected, the
copious details and developments to bemet
with in the larger treatises on the subject;
but enough to serve as an accompaniment
and guide to the physiological student.
   "The attention of the American Editor
 has been directed to the revision  arid cor-
 rection of the text; to the supplying, in the
 form of notes, of omissions;  to  the rectifi-
 cation of some  of t'.ic points that appeared
to him erroneous or doubtful, and to the fur-
nishing of references to works in which the
physiological  inquirer might  meet  with
more ample information.
  " In Phrenology, the Author is a  well-
known unbeliever, and his  published ob-
jections to the doctrine have been regarded
as too cogent to be permitted  to  pass un-
heeded.  It will be seen on farther exami-
nation in the interval of many years, which
has  elapsed since the publication of the
sixth edition of the Encyclopaedia, has not
induced  him  to modify his  sentiments on
this head.  On  the contrary, he appears  to
be as satisfied at this time, of the fallacy of
the positions of the Phrenologist, as he was
i at any former' period."
   fj^7=This work  will be  introduced into
! many of the Medical Colleges of the  union
[ as a Text Book, it being a  cheap udume,
! and well fitted  as an  introduction  to tht
i larger work:: on PhviaoIc>:f,«. 
PUBLISHED BY LEA AND BLANCHARD.
31
COATES    POPULAR    MEDICINE:
               POPULAR   MEDICINE;

                       OR, FAMILY ADVISER.

  Consisting cf  outlines  of Anatomy, Physiology, and  Hygiene, with
such  Hints  on  the Practice of Physic,  Surgery,  and the" Diseases of
Women  and  Children, as may prove useful in families when  regular
Physicians cannot  be procured : Being a Companion and Guide for in-
telligent Principals of Manufactories, Plantations, and Boarding Schools;
Heads of Families, Masters of Vessels, Missionaries, or Travellers, and
a useful  Sketch  for Young Men about commencing the  Study of Me-
dicine.
                  BY REYNELL COATES,  M.  D.

  Fellow of the College of Physicians of Philadelphia—Honorary  Member  of the
Philadelphia Medical  Society—Correspondent of the Lyceum  of  Natural History
of New York—Member of the Academy of Natural Sciences of Philadelphia—Former-
ly Resident Surgeon of the Pennsylvania Hospital, &c.
  Assisted by several Medical  friends.  In One Volume.
  "It is with great satisfaction that we an-
nounce this  truly valuable compilation, as
the most complete and interesting treatise
on Popular Medicine ever presented to the
public.   Simple and  unambitious in its
language, free from the technicalities, and
embracing the most important facts on Ana-
tomy, Physiology  and Hygiene, or the
art of preserving health; and the treatment
of those affections which require immediate
attention, or are of an acute character, this
should be in the hands of every one, more
particularly of those who, by their situations
are prevented from resorting to the advice
of a physician, nor would the careful peru-
sal of its pages fail to profit the inhabitants
of our cities, by giving them a more accu-
rate knowledge of the structure of the hu-
man  frame, and the laws  that govern its
various functions; whose perfect integrity
is absolutely essential to health, and even
to existence; the various systems of medical
charlatanry, daily imagined to take advan-
tage  of the credulity and ignorance of man-
kind, would be rendered far less prejudicial
to the community than they now are.  We
would particularly direct attention to the
Chapter on Hygiene, a science in itself of
the utmost importance, and ably treated in
the small space allowed to it in  this vol-
ume."—New York American.
DR. CLARK  ON CONSUMPTION.

  A Treatise on Pulmonary Consumption,
comprehending  an inquiry into the Nature,
Causes, Prevention, and Treatment of Tu-
berculous and Scrofulous Diseases  in Ge-
neral.   By James Clark, M. D., F. R. S.
  As a text-book and guide to the inexpe-
 rienced practitioner we  know none  equal
■ o it in general soundness and  practical
utility—to the  general as well  as to the
professional reader, the ^  will prove of
The deepest interest, and T< perusal of un-
equivocal advantage."—British  and lo-
reisrn Medical Review,
  £rf he work of Dr. Clark may be rcgard-
  , a5 the most complete and instructive
Trcadse  on Consumption in the English
t Vmiafe."—Edinburgh  Medical  and
Langu"^*
 ^uraicul Journal.
 CHITTY'S  JURISPRUDENCE,

  A Practical Treatise on Medical  Juris-
prudence, with so much of Anatomy, Phy-s
siology,  Pathology,  and  the Practice of
Medicine and Surgery, as are essential to
be known by Members of the Bar and  Pri-
vate Gentlemen; and all the laws relating
to Medical Practitioners; with explanatory
plates.   By J. Chitty, Esq.  Second Ame-
rican edition: with Notes and Additions,
adapted  to American works and Judicial
Decisions. 8vo.
  A TREATISE ON THE PRACTICE
OF MEDICINE, or a Systematic Digest
of the Principles of General and Special
Pathology and Theraputics.  By E. Ged-
dings, (now preparing.) 
32                    MEDICINE AND SURGICAL WORKS.
   SMITH  ON  FEVER.

  A  Treatise on Fever.   By Southwood
Smith,  M. D., Physician to the London
Fever Hospital.  Fourth American edition.
In 1 volume 8vo. •
FITCH'S DENTAL SURGERY.
  A Treatise on Dental Surgery.  Second
edition, revised, corrected, and improved,
with new plates. By S. S. Fitch, M. D.  1
vol. 8vo.
 ABERCROMBIE ON  THE BRATN.
  Pathological  and  Practical  Researches
on  Diseases of  flic  Brain  and  Spinal
Cord.  Second  American, from the third
Edingburgh edition,  enlarged.  By John
Abercrombie, M. D.   In  1 volume 8vo.
ABERCROMBIE ON STOMACH.
  Pathological and  Practical  Researches
on Diseases of the Stomach, the Intestinal
Canal, the Liver, and other Viscera of the
Abdomen.   By John Abercrombie  M. D.,
third American from the second  London
edition enlarged.  In 1 vol. 8vo.
EWELL'S  MEDICAL COMPANION.
  The Medical Companion or Family Phy-
sician :  treating of the Diseases of  the
United States, with their symptoms, causes,
cure, sftid means of prevention.
 BERTIEN  ON  THE  HEART.

  A Treatise on Diseases of the Heart and
Great Vessels.  By J. R. Bertien.  Edited
by  G.  Bouillaud.  Translated  from  the
French. 8vo.
BOISSEAU  ON  FEVER.

  Physiological Pyretology; or a Treatise
on Fevers, according to the Principles of
the New Medical Doctrine.   By F. G.
Boisseau, Doctor in Medicine of the Facul-
ty of Paris, &c. &c.   From  the fourth
French edition.  Translated by J. R. Knox
M. D.  1 vol. 8vo.
BELL  ON  THE  TEETH.

  The Anatomy, Physiology, and Diseases
of the Teeth.  By Thomas Bell, F. R. S.,
F. L. S. &c, third American edition.  In
1 vol. 8vo.  With numerous plates.
WILLIAMS  ON  THE  LUNGS.

  A Rational  Exposition  of the Physical
Signs of Diseases of the Lungs and Pleura;
Illustrating their Pathology and facilitating
their Diagnosis.  By Charles J. Williams,
M. D.  In 8vo. with plates.
  IIUTIN'S  MANUAL.

  Manual of the Physiology of Man; or a
concise Description  of the Phenomena of
his Organization.  By P. Hutin.   Trans-
lated from the French, with notes, by J.
Tojrno.  In 12mo.          »_
   THE BRIDGE WATER TREA-
 TISES, COMPLETE  IN  SEVEN
 VOLUMES, OCTAVO.  Embracing.
   I. The Adaptation of External Nature
 to the Moral and Intellectual Constitution
 of Man. By the Rev. Thomas Chalmers.
   II. The Adaptation of External Nature
 to  the  Physical Condition of  Man.  By
 John Kidd, M. D., F. R. S.

   III. Astronomy and  General Physics,
 Considered with  References to  Natural
 Theology.  By the  Rev.  Wm. WhewelL

   IV. The  Hand:  Its  Mechanism and
 Vital Endowments  as  Evincing  Design.
 By Sir Charles Bell, K. H., F. R. S.  With
 numerous wood cuts.

   V. Chemistry,  Meteorology,  and  the
 Function of  Digestion.   By Wm. Prout,
 M. D., F. R. S.

   VI. The History, Habits and Instincts
 of Animals.  By the Rev. Wm. Kirby, M.
 A., F. R. S.  Illustrated by numerous En-
 gravings on Copper.

   VII.  Anatomy and Vegetable Physiology
 Considered  with  Reference  to  Natural
 Theology.  By Peter Mark Roget,  M. D.
 Illustrated  with  nearly  Five  Hundret
 Wood Cuts.

  VIII. Geology  and  Mineralogy,   Cor-
isidered with Reference to,Natural  Ther-
| logy.  By the Rev. Wm. Buckland, D. D.
 wuh numerous .engravings on copper, and
 a large coloured map.
  V The work of Buckland,  Kirby  and
Rojot may be had separate.
!6C
*r\ 
 
NATIONAL LIBRARY OF
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