THE INTESTINES. 
285 
larger in dimensions than the stomach itself; it then begins to 
contract, and continues to do so gradually until it has com¬ 
pleted its second convolution round the csecum, or blind 
gut, where its dimensions are not more than one of the small 
intestines. 
b. The csecum, or blind gut, which is the first subdivision of the 
large intestines, originating in a large capacious receptacle, 
called the ccccurn caput coli , or blind head of the colon, from 
which it extends downward and terminates in a blind extre¬ 
mity. The caecum differs from all the other intestines in 
having but one opening into it, so that all the substances which 
enter into it must reascend into the caput coli, in order to be 
carried through the intestine. The exterior parts are braced 
by three longitudinal bands, and puckered by them into three 
sets of cells internally, which will be better understood by a 
reference to plate ix. fig. 3. 
c. A portion of the mesentery. It is a duplicature of the peri¬ 
toneum, which bears this appellation. The colon is attached 
in like manner to the bone by a production of the same mem¬ 
brane, called the mesocolon, and the rectum is kept in its place 
by a similar reflection, called the mesorectum 
cL e, Are portions of the small intestine. 
/. The beginning of the colon. 
g. The rectum. As soon as the colon has reached the basis of 
the sacrum, it ends, and it then assumes the name of rectum, 
being to a certain extent straight; however, it is not perfectly 
so, as it follows the curve of the bone. It terminates by a 
large extremity, called the anus. The rectum will hold about 
three gallons of water or fluid matter. The outer extremity is 
furnished with a circular muscle, called the sphincter ani, the 
use of which is to keep the anus closed, to retain the feculent 
matter until so much of it be accumulated in the rectum as to 
excite a desire to discharge it. 
PLATE IX. Fig. 1. 
This figure is intended to display the relative situations 
of the principal organs, with only part of the intestinal 
canal These lie exteriorly to other important viscera 
T 
