most accessible for such purposes, the struc-
ture and habits of the Dog render its sto-
mach, in many respects, one of the best we
can select for examination.
In this animal, the tubes of the cardiac
extremity (B, Jig. 248.) begin on the free or
Mucous membrane from the middle of the Dog's
stomach, as seen from the free surface. ' Magnified
150 diameters.
a, ridges which intervene between the primary
tubes, covered by columnar epithelium ; b, primary
tubes, lined by similar columnar cells ; c, secondary
tubes, given off from the preceding, and lined, at
their commencement, by similar cells; d, central
calibre, or cavity, of a secondary tube.
cavitary surface of the organ, by apertures
which form the intervals of a kind of net-
work of ridges. These apertures are polygonal,
or irregularly six-sided, and the tube into
which each soon merges has a diameter that
is very little less than the distance between
the ridges j on an average about ^^th of
an inch. The tube now proceeds down-
wards for a short distance, before bifur-
cating into two smaller tubes. And each of
these again divides at a further stage of its
descent. In this manner, what was at first
a single large cylinder, ends as a bundle of
about four or five small tubes, which are col-
lectively enclosed in a portion of matrix
thicker than that occupying their interstices.
At the pyloric extremity of the organ, the
tubes (A,j%.248.) commence by apertures,which
have a diameter twice as great as those seen
in the cardiac region, and from hence they
pass vertically downwards for some distance,
with a simple cylindrical form. All the ter-
minal branches of these long pyloric tubes
are for the most part given off at nearly the
same height, so that they constitute only
one-sixth, or thereabouts, of the whole thick-
ness of the mucous membrane, instead of
about five-sixths, as in the cardiac extremity.
In both the above regions, however, the num-
ber of these terminal tubes is rarely less than
three, or more than six. Their diameter is
generally about one-third that of the larger
and simple tube from which they originate.
And the total bulk of the bundle which they
form, as seen on transverse section, is as
nearly as possible equal to that of the primary
tube.
But these differences in the width and
ramification of the cardiac and pyloric tubes
are accompanied by a much more remarkable
and important contrast in the form, size, and
arrangement of their respective contents.
The whole of the pyloric tube (A,/g. 248.)
is occupied by a single layer of columnar epi-
thelium, the cylindrical or slightly prismatic
cells of which are placed vertically to the
basement membrane, and contain a very dis-
tinct nucleus near their attached extremity.
The only difference offered by these cells '.in
the terminal branches of the tube is, that they
are shorter in proportion to their width, and
enclose darker and more granular contents.
Fig. 248.
fMi^feiS>> ^SlSiflg^
Tubes from the cardiac and pyloric regions of the
Dog's stomach, to show the contrast of their struc-
tures. Magnified 60 diameters. Altered from
Koelliker.
A. pyloric tube ; a, primary tube ; b, three second-
ary tubes. B. cardiac tube ; a, primary tube lined
by columnar epithelium ; b, two secondary tubes ;
c, four terminal branches containing large oval
cells.
STOMACH AND INTESTINE.
323
They everywhere bound a tube with a dis-
tinct calibre.
In the cardiac region, it is only the ridges,
and the upper part of the tubes, which are
covered by columnar epithelium. At the
first (B b, fig. 24-8.) or second bifurcation of
the primary tube, the character of its lin-
ing altogether changes : and from hence
onwards to their rounded blind extremities,
the secondary tubules are immediately lined
by peculiar oVal cells (B c, fig. 243.). These
cells are analogous to those seen in the
human stomach. They differ however from
them, not only in their great size, and more
distinct walls," but also in the fact, that they
generally bulge the basement membrane of
the tube, so as to give it a somewhat moni-
liform outline. A closer examination shows
this appearance to be caused by the prominent
cells occupung irregular heights around the
wall of the tube.
On getting the middle of such an isolated
tube into the focus of the microscope, we find
tiiat in the higher part of the tuDule, near
where it opens into the primary tube, the
oval cells, which are always in immediate
contact with the basement membrane, form a
double row with a somewhat sinuous interval.
This interval is a distinct though narrow
calibre. Below this visible calibre, I had
long been aware that the similar interval
between the larger cells was occupied by an
immense number of small nucleated cells or
cytoblasts, many of which are firm, with dis-
tinct and somewhat angular outlines; while
others are excessively delicate, pile, flattened,
oval, transparent, and of equal or much smaller
size. And the more skilful manipulation of
Koelliker has recently enabled him to state,
that the centre of the tube presents a con-
tinuous narrow calibre or cavity (-*,/#. 249.),
which is immediately bounded by these small,
roundish, or angular cells (c, A and B). Be-
tween these small cells and the limitary mem-
brane, the large oval cells are interposed
(b, A and B). Bt?low, the latter often seem to
form the sole contents of the tube.
The truth of Koelliker's description I can
fully substantiate ; so far as regards the upper
part of these secondary tubes, in the cardiac
five-sixths of the organ. Even the blind ex-
tremities of the tubes seem to have their
axes occupied by the delicate cytoblasts pre-
viously alluded to ; but they are here, so far
as I can see, disposed irregularly. Higher up,
the cells are more angular, and possess more
distinct outlines; and are often arranged in
two rows, which are in contact at the centre
of the tube. It is only towards the apertures
of the secondary tubes," where the oval cells are
beginning to be more thinly scattered prior
to their disappearance, that these small cyto-
blasts appear to form a distinct calibre or
tubular cavity of appreciable width. Here
they merge into the columnar form; a change
which begins by their becoming elongated to-
wards the axis of the tube, and allowing water
to develope a distinct cell-membrane at this
part (c,Jig. 249.). But there are many appear-
ances which render it by no means impossible
that the whole length of the tube possesses a
narrow calibre, formed by a regular arrange-
Fig. 249.
Portions of tubes from the cardiac extremity of the
dog's stomach. Magnified 350 diameters. (Partly
after KoeUiker.)
A. portion from the middle of such a cardiac
tube ; a, limitary membrane of tube ; b, large oval
gastric cell ; c, smaller axial cells. B. Same seen
in transverse section ; a, b, c, as above. External to
c are seen indistinctly some delicate cytoblasts ; c,
junction of the primary and secondary tubes, show-
ing the mode in which the small axial cells of the
latter are continuous with the columnar cells which
form the epithelium of the former.
ment of these small cells. While I have no
doubt that the interstices left between the
large cells and this central tube of epithelium
are also filled up by numbers of cytoblasts, of
excessive delicacy, and various degrees of mi-
nuteness ((/, B and c).
Besides these free cytoblasts within the tube,
we may find others of endogenous origin. Very
careful observation of the large oval cells will
show that they enclose cytoblasts in addition
to their minutely granular contents (compare 6,
Jig. 246.). The number of these cytoblasts ap-
pears to vary from two to twenty in different
cells. They are excessively delicate, of about
1 nnrvth inch diameter: their shape is a flat-
tened oval ; and they contain a bright spot or
nucleus. They seem to be chiefly in contact
with the inner surface of the mother-cell ; so
that in many animals, specimens of their out-
line can often be distinctly seen through the
nearly transparent wall of this cell under the
higher powers of the microscope. They may,
however, be easily overlooked. And their
distinctness never equals that of the proper
nucleus of the cell ; closely as they resemble
this structure in size and shape. They may
sometimes be seen projecting from the broken
half of a mother-cell ; or set free from it,
owing to its having been ruptured by the
Y 2
324
STOMACH AND INTESTINE.
rapid endosmose of water. But they are very
quickly dissolved or burst, by contact with
most of the fluids which are generally used
in preparing such specimens for microscopic
examination.
During the five years that I have made the
stomach an object of frequent (though inter-
rupted) research, I have examined numerous
specimens from the perfectly fresh stomachs
of about thirty species of Vertebrata. The
following is an outline of the few results I
have obtained. As regards the pyloric tubes,
those of the Cat, Rabbit, Hog, Ox, and
Guinea-pig, resemble those of the Dog, in
containing a columnar epithelium, and having
a distinct calibre to their termination. Those
of the Horse resemble the tubes of the human
stomach in possessing the oval or gastric cells.
In most, if not all of these animals, the tubes
ramify. As respects the cardiac tubes, the
minute central calibre observed by Koelliker
in those of the Dog appears to be also present
in the Cat and Guinea-pig ; and, from analogy,
is not unlikely to exist in most Vertebrata.
The large oval cells are the rule throughout
the Vertebrate kingdom. And in many Rep-
tiles, as well as in the very young animals of
most orders, the numerous cytoblasts enclosed
by these cells are much more distinct. In
only two instances have I found no large
cells present in the cardiac tubes, and in both
of these, the stomach was evidently disorgan-
ized by commencing putrefaction. In some
Fishes, however such as the Mackerel it
is only the middle or apex of the F-shaped
stomach which is occupied by tubes. And
in the Minnow, Carp, and Tench of the
Cyprinoid genus, as well as in the river Lam-
prey (Pelromyzon fluviatile) no tubes are
present. Finally, while there are many species
in which the gastric structures appear to be
softer and more delicate during the time of
digestion than in the fasting state, in none
have I been able to verify the least difference
in the morphology of the organ at these two
periods.
Those who are familiar with the diffi-
culties that oppose the successful examina-
tion of the softer tissues of the animal body
will probably bear with me if I end this de-
scription by what may seem a superfluous
caution to the observer. There are many
appearances seen in these delicate tubes, which
are produced by the mechanical violence
necessary to their isolation, aided by the
softening of incipient putrefaction or self-
digestion, or by the endosmose of the di-
lute fluids which are sometimes added to
such specimens in preparing them for the
microscope. Thus the tubes often deviate
from the above account in the absence of
gastric cells, in the presence of short branches
that are given off near their blind extre-
mities, and in the spiral or bulbous shape
which these ends sometimes assume. Indeed,
when we reflect upon the extreme tenuity of
their basement membrane, the nature of their
contents, and the firmness with which they
are imbedded in a dense areolar and muscular
tissue, we shall scarcely be surprised to find,
that the violent disruption of these attach-
ments can distort the tubes, or break up their
soft contents. But the careful manipulation of
perfectly fresh specimens, in a proper fluid me-
dium (such as the serum of the blood, or a
strong solution of common salt) renders these
appearances so rare, as to render it highly
probable that they are accidental. While
conversely, the application of a slight pres-
sure, the use of water and dilute acids, and
the commencement of digestive or putrefactive
softening, will often produce them in a spe-
cimen from which they were formerly absent.
In addition to the cylindrical tubes, some *
anatomists have found in the stomach ramified
glands, which end in acini or dilated extre-
mities. These are stated to occupy the
neighbourhood of the pylorus, wherethey form
a kind of transitional structure between the
gastric and the duodenal glands. I have once
or twice seen appearances in the tubes of this
part which corresponded pretty closely with
the above description. In two other instances,
a single flask-shaped dilatation was appended
to some of the ordinary tubes, which it thus
doubled in diameter. But the arrangement of
these latter dilatations, as well as the condition
of the remainder of the specimens, left me little
doubt that they were due to accidental
violence, which had distended the terminal
branches of a tube with a large portion of its
displaced contents. While their shape and
situation (in the mucous membrane itself,
instead of its submucous tissue) sufficed to
show that they were not lenticular glands ;
an argument which will equally militate
against the notion of their being a transition
to the duodenal glands, since these occupy a
similar position.
Lenticular glands are also found in the
stomach. As regards their shape, size,
situation, and contents, they correspond so
completely with the solitary glands of the
intestine, that we may refer the reader to
these for their special description. Their
number varies extremely. Sometimes it is im-
possible to find any. In other specimens, they
are scattered more or less thickly through-
out the whole organ. They are said chiefly
to affect the lesser curvature ; but I have seen
them sown very plentifully over the pyloric
region only. In children* they are rarely
absent. And among the brute Mammalia,
they are found occasionally in the Dog f, and
constantly in the Pig. % Structures more or
less analogous to these glands probably also
exist in the Beaver, Kangaroo, Dugong, and
many other animals.
Matrix. The cylindrical tubes of the sto-
mach are united to" each other, in their whole
length, by a sparing quantity of a fibrous
* Bruch (in Henle and Pfeufer's Zeitschrift. f.
Rat. Path. Bd. viii. p. 272. et seq.) ; Ecker (id. op.
1852. p. 244.). Compare Bischoff (in Mueller's Ar-
chiv. 1838. p. 503.)
f Bischoff, Op. cit. p. 510.
j Id. op. ; also Wasmann (DeDigestione Nonmilla.
Berlin. 1839. p. 8.), and Koelliker, Op. cit. p. 150.
STOMACH AND INTESTINE.
325
network or matrix; their blind extremities
being also imbedded in a considerable stratum
of this texture, which is continuous with that
surrounding their sides. The arrangement of
the latter part of it is best seen by making hori-
zontal sections of the mucous membrane, so
as to cut transversely across the gastric tubes
at different heights. Its quantity is small in
proportion to the diameter of the tubes. And
in it we may recognize, besides cut extremities
of vessels, indistinct concentric fibres, which
appear to surround the tubes, and decussate
with each other. In the ramified tubes of
many animals, each original tube, and its set
of secondary branches, is enclosed in a tole-
rably thick sheath of this kind, which gives
off slenderer partitions of the same nature
between the smallest individual tubes. On
the surface of the stomach, this matrix is
nearly homogeneous ; but its fibrous cha-
racter is more distinct at the deeper parts of
the membrane, and in those tubes which
occupy the neighbourhood of the pylorus.
Here its quantity is also increased. Many
years ago, the author was struck with the re-
markable difference between that layer of this
fibrous tissue which lies beneath the tubes, and
the submucous areolar tissue upon which it is
placed ; the former being characterized,
not only by its darker colour, and its dense
and closely interwoven texture, but also by
its being much less acted on by acetic acid.
But Middeldorpf* has since made the im-
portant discovery, that this peculiar layer,
which extends from the cardia to the anus,
is in reality composed of a mixture of
areolar tissue, and organic or unstriped
muscle: the fibres of the latter structure
being arranged in two series of bundles that
decussate with each other at an acute angle.
Externally, these fibres are conjectured by
Kcelliker* to be more or less continuous
with the ends of the oblique fibres of the
muscular coat. Internally, Bruecke states
them to pass upwards, in small bundles,
between the several tubes. This statement
is to some extent confirmed by Koelliker,
who has seen numerous cells very like
the fibre-cells of organic muscle occupying
this situation in Man, some Ruminants, and
the Pig. In the latter animal, bundles of these
fibres penetrate the rudimentary villi of the
pylorus, and occupy their axes. Of the
function of these muscular-fibre cells we
know nothing. But, from their arrangement,
it would seem not impossible that they are
destined to maintain the tubes in their normal
situation, against the disturbances which the
contractions of the proper muscular coat might
otherwise produce.
Areolar tissue. A layer of loose submucous
areolar tissue (the tunica nervea of some
authors) connects the mucous membrane of the
stomach with the proper muscular coat pre-
viously described. Seen in vertical section, its
thickness is a little greater than that of the
denser muscular stratum which receives the ex-
* De glandnlis Brunnianis. Vratisl : 1846.
tremities of the tubes. Its constituents are
the ordinary white and yellow fibrous ele-
ments ; the elastic filaments of the latter
being chiefly of small size. Externally, it
is pretty firmly connected with the muscular
coat, and appears to receive many of its
fibres. But internally, where it approaches
the fibrous matrix, its meshes are very
large and loose, so as to allow of the
mucous membrane being thrown into folds by
the contraction of the muscular tunic. ft
contains the vessels, nerves, and lymphatics
destined for the supply of the mucous mem-
brane.
The vessels of the stomach are very large
and numerous. The arteries are derived from
the abdominal aorta. The veins empty
themselves into the vena portce t which rami-
fies in the liver.
The arteries of the stomach all come off
from the coeliac axis. This vessel, which
leaves the aorta opposite the first lumbar
vertebra, continues obliquely forwards as i\
short thick trunk for a distance of about half
an inch ; when the " axis " ceases, by giving
off, at right angles to itself, three large
branches : namely, the gastric, hepatic, and
splenic.
Fig. 250.
Arteries of the stomach. The coeliac axis, as seen by
raising the liver, and depressing the stomach.
a, arteria coronaria ventriculi ; b, gastric branches
of the same; c, arteria hepatica ; d, arteria gastro-
duodenalis; e, arteria gastro-epiploica dextra; g,
arteria py lories ; h, arteria splenica ; i, arteria gastro-
epiploica sinistra.
The arteria coronaria ventriculi (a, Jigs. 250,
25 1 .), or proper gastric artery, is the smallest of
these three. It passes upwards and towards the
left side, beneath the peritoneum which forms
the dorsal and outer surface of the sac of the
Y 3
326
STOMACH AND INTESTINE.
omcntum ; until, arriving nearly at the upper
extremity of this cavity, it turns forwards in
a slight projection or fold of the serous mem-
brane. In this fold, it has a very brief and
somewhat arched course, which brings it to
the left end of the smaller curvature of the
stomach. Here it passes between the two
layers of the gastro-heptitic omentum. From
hence it continues, in a very tortuous course,
along this curvature ; lying close to the
stomach, and diminishing in size by giving off
frequent branches; until, towards the right or
pyloric extremity of the organ, it is lost by
anastomosing with the branches of the hepatic
artery.
Its larger or named branches are the ceso-
phagcaland the gastric. The first are given off
from the highest point of the vessel, or where
it enters the gastro-splenic omentum. They
run upwards to the oesophagus, and take a
longitudinal course ; so as to pass, with this
tube, through the opening in the diaphragm.
And they anastomose with the thoracic vessels
distributed to this tube from the aorta. The
gastric ramifications (b,jfig. 250.) run down-
wards from the coronary artery on both surfaces
of the stomach. They inosculate, on the left,
with small branches from the splenic artery ;
towards the middle of the organ, with the
gastro-epiploic branches ; and at the p} lorus,
with the superior pyloric artery.
The arteria hepatica (c, figs. 250, 251.),which
is the next largest branch of the cceliac axis,
passes for a short distance outwards, and slightly
forwards, from the axis or common trunk, to
reach the commencement of the duodenum. It
now runs almost vertically upwards between the
two layers of peritoneum that form the gastro-
hepatic omentum, and in front of the foramen
of Winslow (though still with a 'slight incli-
nation towards the right side), to end by being
distributed in the liver. In this course, it
gives off two branches, the gastro-duodenal
and the pyloric both of which take an
important share in supplying the stomach
with arterial blood.
Fig. 251.
Arteries of the stomach. The cceliac axis, as seen ly
raising the stomach, so as to expose the arterial
brandies behind it.
a, arteria coronaria vcntriculi ; c, arteria hepatica ;
d, arteria gastro-duodenalis ; e, arteria gastro-epi-
Ploica clextra ; f, arteria pancreatico-duodenalis ; g,
arteria pylorica ; h, arteria splenica ; /, arteria gastro-
e^iploica sin'stra.
The gastro-duodenalis (r/, Jigs. 2 50 ,25 1 .) is the
first and largest artery of these two. It leaves
the hepatic vessel behind the duodenum, passing
vertically downwards across the intestine to
the lower border of its first portion. In this
course, it gives off a few small branches to
the neighbouring parts of the stomach and in-
testine ; some of which twigs have been dis-
tinguished as the inferior pyloric arteries.
And at the inferior margin of the bowel, the
gastro-duodenal artery bifurcates into two :
a large gastro-cpiploic, and a small pancrea-
tico-duodenal branch.
The gastro-epiploica dextra (^,^^.250,251.),
the large vessel which continues the gastro-
duodenalis, is so named from its situation be-
tween those layers of the great omentum which
descend from the stomach to form the " epi-
ploon "or apron -like fold that covers the greater
part of the intestinal canal. Beginning at the
lower border of the duodenum, the artery runs
from right to left, along the lower margin or
great curvature of the stomach, and at a
little distance from it, with what is usually a
wavy or tortuous direction. In this course,
it gives off branches which pass upwards on
both surfaces of the organ ; as well as others
of less importance, both upwards and down-
wards, to the fatty and serous tissues of the
omentum itself. And rather beyond the
middle of the stomach, or towards its cardiac
pouch, it ends by uniting with a corre-
sponding branch, of smaller size, from the
splenic artery.
The panmeatico-duodenalis branch (/, fig.
251.) has precisely the situation and distri-
bution which its name would imply. It runs
between the duodenum and the head of the
pancreas, lying in the concavity formed by
the horse-shoe curve of the canal, or around
the convexity by which the gland fits into this
hollow. It gives off ramifications to both these
structures, and ends by anastomosing with a
branch, which comes upwards from the su-
perior mesenteric artery and also occupies
the same interval between the pancreas and
the lower portion of the duodenum.
The arteria pylorica (g, figs. 250, 251.),
which is sometimes distinguished by the title
of the pylorica superior from the smaller
branches of the gastro-duodenal above allu-
ded to, is generally given off from the trunk
of the hepatic artery opposite to the upper
border of the duodenum. More rarely it is
derived from the commencement of its gastro-
duodenal branch. In either case, it enters
between the layers of the gastro-hepatic omen-
tum, and runs in this fold, from right to left,
along the upper margin or lesser curvature of
the stomach, to join the coronary artery from
the cardiac extremity of the organ. It gives
off numerous branches to both surfaces of
the organ.
The arteria splenica (h, figs. 250, 25 1 .), or
second branch of the cceiiac axis, has no