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 caecum, or blind 

 gut, where its dimensions are not more than one of the small 

 intestines. 



b. The caecum, or blind gut, which is the first subdivision of the 

 large intestines, originating in a large capacious receptacle, 

 called the cacum caput colt, or blind head of the colon, from 

 which it extends downward and terminates in a blind extre- 

 mity. The csecum 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. Tt 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. 



df e, Are portions of the small intestine. 



f. 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 



