THE LIVER 465 
The large intestine is much smaller in caliber than that of the horse, has no 
bands, and is not sacculated. Most of it is situated between the layers of the 
common mesentery in the right dorsal part of the abdominal cavity. It is related 
on the right to the lateral abdominal wall, from which, however, it is almost com- 
pletely separated by the greater omentum. On the left it is chiefly related to the 
rumen. The average length of the cecum is about thirty inches (ca. 75 em.), and 
the diameter is about five inches (ca. 12 cm.). It is directly continuous in front 
with the colon, the conventional demarcation being the junction of the ileum with 
the large intestine.t From this junction, which is on the medial side and usually 
near the ventral end of the last rib, the cecum extends backward and upward 
along the right flank (from which it is separated by the greater omentum), and its 
rounded blind end commonly lies at the right side of the pelvic inlet. The cecum 
is attached along its medial side to the mesentery, except the posterior third, which 
is free and variable in position. The terminal part of the ileum runs forward along 
the medial surface of the ezecum and is attached to the latter. The dorsal surface 
is attached by areolar tissue and peritoneum to the colon. The colon is about 
thirty-five feet (ca. 10 m.) in average length. Its diameter is at first the same as 
that of the cecum, but diminishes to about two inches (ca. 5 cm.). The greater 
part of it is arranged in double elliptical coils between the layers of the mesentery; 
the coils are attached to each other by areolar tissue. It begins as the direct 
continuation of the ezcum, runs forward a short distance, and turns dorsally and 
backward opposite to the ventral part of the last two ribs. It continues backward, 
in relation to the right flank laterally and the cecum ventrally, to the posterior 
part of the sublumbar region. Here it turns forward and runs parallel with the 
retrograde part as far forward as the second lumbar vertebra, turns backward, and 
is continued by the spiral part (Ansa spiralis). The coils of this are alternately 
centripetal and centrifugal (Gyri centripetales et centrifugales); they are best 
seen from the left side. The bowel gradually diminishes in caliber, and the ter- 
minal part (Ansa distalis) leaves the spiral mass, passes forward to the great mesen- 
terie artery, and runs backward dorsal to the terminal part of the duodenum. It 
inclines to the right in relation to the ventral surface of the right kidney, forms an 
S-shaped curve near the pelvic inlet, and joins the rectum; this part is attached to 
the sublumbar region by a narrow mesentery, and is also attached to the recurrent 
part of the duodenum. 
The rectum is somewhat shorter than that of the horse, and is usually covered 
with peritoneum as far back as the first coceygeal vertebra. The retroperitoneal 
part is surrounded by a quantity of fat. The anus is not prominent. 
The serous coat is of course absent on the adherent surfaces of the spiral part 
of the colon. There is a large amount of fat in the mesentery. The longitudinal 
fibers of the muscular coat are evenly distributed, consequently there is no saccula- 
tion of the bowel. There is a valvular mucous fold at the ileo-cxeal orifice. A 
Peyer’s patch occurs in the beginning of the cecum and one in the first part of the 
colon. 
THE LIVER 
The liver lies almost entirely to the right of the median plane. Its long axis 
is directed obliquely downward and forward, about parallel with the median plane, 
and corresponds to the curvature of the right portion of the diaphragm. It is less 
extensive, but thicker than that of the horse. Its average weight is about 10 to 
12 pounds (ca. 4.5 to 5.5 kg.). 
‘In formalin-hardened material there is sometimes a constriction in front of the termination 
of the ileum. This might be regarded as the demarcation between the cecum and colon. The 
opening of the ileum is directly forward, so that material from it enters the origin of the colon. 
The posterior free part of the cecum is naturally variable in position; it may be bent ventrally, 
So that the blind end faces forward. 
