ABDOMINAL VISCERA OF THE HORSE. 19 
where it traverses the direction of the spine, resting on the 
ensiform cartilage ; turning round the left side, it attains the 
left iliac fossa posteriorly, where it forms a twist like a letter S, 
from which similitude it has been termed the Sigmoid Flexure 
of the Colon. The gut, having diminished in size, returns up 
the same side of the abdomen to the diaphragm, where it again 
crosses the spine. Being now on the right side, it continues 
back to a point beyond the anterior mesenteric artery, where it 
turns upwards and forwards, so as to come in front of the 
artery in question ; then, from right to left, so as to cross the 
spine for the third time, constituting the transverse colon, which 
is more capacious than the part preceding it. The two curves 
which it forms, one on the right and the other on the left, are 
respectively called the hepatic and gastric flexures of the colon. 
The gut so proceeds backwards along the left side of the mesen¬ 
tery, being diminished again in size, and constituting the single 
colon, till we get to the posterior mesenteric artery, where, 
unaltered in other respects, it takes a straight course through 
the pelvis, out at the anus, and hence the name of Rectum. 
The caecum, so called from having only one outlet, being 
closed at its anterior part, or caecum caput coli, from its being 
the blind head of the colon, is vulgarly termed the water-bag, 
owing to the almost invariable fluidity of its contents. 
It is situated, as I have before said, obliquely along the floor 
of the abdomen, extending backwards from left to right. 
It is attached to the spine by a meso-caecum, which is a fold 
of peritoneum coming off from the spine on to the superior part 
of the pouch. There is then the fold already alluded to, which 
stretches from the ileum on to the caecum, and, through the 
medium of the mesentery, indirectly connecting the latter with 
the spine. 
The caecum is cone-shaped, having an apex and a broad base. 
The former generally protrudes the first when a medium longi¬ 
tudinal incision is made into the abdominal walls, although it is 
situated above the left portion of the double colon, whilst the 
liver is directly in contact with the floor of the abdomen. Like 
the other divisions of the large intestine, the caecum is saccu¬ 
lated. The bands producing this appearance are three in 
number at the apex; but between two and three inches from 
this, one of them bifurcates, so that four bands result, which are 
continuous on to the colon. 
The colon arising from the caecum receives at first the con¬ 
tents of the ileum, being situated along and occupying the 
greater part of the floor of the abdomen. 
The colon is generally distinguished as double and single. 
Bv double, is meant the flexures of the gut from its commence- 
