(Esophagus.—This is 1 foot in length, and 3*75 inches in breadth at the base
of the epiglottis; 6 inches behind this, it contracts to 2*50 inches, dilating again at
the orifice of the stomach to 3 inches. I t is capable of great distension. The
muscles consist of two layers. Posteriorly, the first or external layer passes from
within outwards, the fibres in the middle being longitudinal, or nearly so; the lateral
fibres are oblique, winding round the side of the tube to the ventral aspect, and are
so crowded together at the side, that they produce the appearance as if this portion of
the tube were provided with a special muscle. They terminate in a longitudinal line
corresponding to the side of the trachea. Some of the external oblique fibres give
off long loops which rim across the oesophageal wall, in some cases at right angles.
The second or internal layer on the posterior aspect is transverse, and appears to be
continuous at the lower end of the oesophagus, with the obliquely transverse thin
layers of the interval between the tracheal margins.
Microscopic structure.—The mucous membrane of the oesophagus near its lower
end is of considerable thickness, and the papillae are long and filiform; the epithelial
cells being large and polygonal. I have not been able to detect any glands besides
the ordinary mucous glands, which are most numerous near the anterior end of the
tube.
Relations o f stomach m the adult.—The left division of the stomach is almost
wholly hidden by the liver, and lies slightly posterior to the right sac. When inflated,
it is placed rather obliquely across the abdominal cavity in an antero-posterior
direction, with its apex directed downwards to the right side, many inches anterior
to its oesophageal orifice, which latter is slightly dorsally placed to the opening
between the two stomachs. The right division lies obliquely across the abdomen
hidden by the liver, except along its lower margin, which describes a curve of nearly
half a circle. I t rests on the left half of the first sac, and its apex is directed downwards
to the right side, tending backwards and slightly upwards and then backwards,
downwards and outwards to the left, to its junction with the third cavity. This
latter lies behind, and is nearly covered by it. The oesophageal orifice is opposite the
sixth rib, 7 inches from its distal extremity, and its apex is opposite and distant 2 inches
from the distal end of the eighth rib. With the specimen placed on its back, this
section of the stomach (second cavity) reaches the sternal attachment of the second
rib, and, when fully inflated, it rises from 2 • 50 to 3 inches above the level of the
oesophageal orifice. The third sac lies posterior to the second, and passes to the left
nearly as far as the mesial line, where it is continuous with the duodenum which
runs downwards and slightly to the left on a line with the lower margin of the mass
of the stomach and posterior to the intestines.
Relations of stomach in the foetus.—The mass of the stomach lies to the left
of the mesial line of the body, and the second or right cavity hides the left, which
lies behind it. The apex of the first cavity is directed backwards, so that the sac is
almost transverse to the longitudinal axis of the abdomen. The second sac occupies
the greater part of the left half of the abdominal cavity, but extends slightly to the
right of it. Its apex is bent upon itself, passing backwards and downwards to the
left. The third cavity and duodenum pass to the left side behind the whole
mass of the small intestine, where the jejunum rests at the left side on the large
intestine, when it again bends abruptly round to the right side. The head of
the large intestine abuts against the inferior wall of the second stomachic cavity
on the left side, and the greatly enlarged csscum lies below and in contact with the
stomach transverse to the abdominal cavity; its apex resting against the umbilical
vein, and its body being buried among the coils of the small intestine. The large
intestine, which is quite as capacious a tube as the small gut, has a general upward
direction from right to left. In this foetus, which is very near its full time, there is
no trace of a transverse colon; indeed, the head of the large intestine is only in
contact with the inferior wall of the left cavity of the stomach; the whole of the
tube being as yet restricted to the left side of the body. The sigmoid flexure rests
against the lower half of the inner wall of the left kidney, and is nearly concealed
by the uterus.
Stomach.—This organ conforms to the general type in Cetacea. I t consists
chiefly of two large sacs, placed side by side, opening into each other by a common
orifice at the termination of the oesophagus. The first or left cavity is perfectly
simple, but the second presents a sacculation in the right wall of its fundus; this
leads into a short narrow passage or channel which conducts to the third cavity,
this latter being about one-eighth the capacity of the others.
First cavity.—This (PI. XXV, fig. 1 ,1) must be regarded as simply a dilatation
of the oesophagus. It is slightly elongated, and more bulging on its left than on its
right margin, with its anterior wall convex from before backwards. The oesophageal
orifice is marked in some conditions by a series of strong folds which radiate downwards
and outwards along the inner aspect of the walls of the sac, and assist in
closing the orifice when it is contracted. The walls are very strong and muscular,
and thicker than those of the second stomach, from which they also differ in structure.
They have the palish-yellow tint of the oesophagus, while those of the right
cavity are pinkish-grey. Besides the folds already described, the walls in some
instances are covered, at tolerably regular intervals, by an extensive series of transverse
grooves, which, separating the foregoing folds, divide the inner aspect of this
cavity into numerous rounded oblong areas, and produce an appearance resembling
the convolutions of a mammalian brain, an effect which is heightened by the
circumstance that many of the transverse grooves are not continuous throughout
their length. The latter only appear about two inches below the oesophageal opening,
so that there is a broad area around it, marked only by longitudinal folds, In
one adult stomach examined, a perfect cast of the inner surface of this cavity
was noticed in the process of being thrown off as a layer of mucous membrane, about
0-02 inch thick, and rough to the touch. In this state it had a pale-yellowish colour,
and the folds were divided crosswise, so that the membrane had a tessellated character,
consisting of little raised oblongs, about half an inch broad and an inch long.
Prom the relative position of the two cavities already noticed, the common
opening between them looks obliquely from left to right, the right margin of the
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