THE INTESTINES. 



479 



already given when speaking of the attachments proper to the cgecum. The 

 muscular tunic is formed of circular fibres, crossed externally by longitudinal 

 bands, which maintain the organ in transverse folds. The mucous membrane is 

 thicker than that of the small intestine, and is also distinguished from it by the 

 absence of the Brumierian and agminated glands. It has, however, the solitary 

 follicles and crypts of Lieherkiikn, as well as some few intestinal villi. The blood- 

 vessels are the ccecal arteries and veins. The lymphatics pass to the sublumbar 

 receptacle ; the nerves are derived from the great mesenteric plexus. 



Functions. — The csecum serves as a reservoir for the enormous quantities of 

 fluid ingested by herbivorous animals. The greater part of this fluid in its rapid 



Fig. 282. 



GENERAL V/EW OF THE INTESTINES OF THE HORSE (SEEN FROM THE RIGHT SIDE, WITH THE 

 PELVIC FLEXURE AND A PORTION OF THE SMALL INTESTINE CARRIED BEYOND THE 

 ABDOMINAL CAVITY). 



a, CEsophagu'j; 6, right sac of the stomach; c, small intestine, showing its origin or duodenal por- 

 tion, encircling the base of the caecum ; d, caecum ; e, origin of the large colon ; /, first portion 

 of the large colon ; g. supra-sternal flexure ; h, second portion of the large colon ; i, pelvic flexure; 

 j, third portion of the large colon; k, diaphragmatic flexure; I, fourth portion of the large colon; 

 m, termination of the free colon; n, rectum; o, mesentery proper; p, colic mesentery (meso- 

 colon) ; q, anus ; r, internal inguinal ring ; s, spermatic vessels ; t, deferent canal ; u, bladder ; v, 

 vesiculse seminales; x, pelvic enlargement of the vas deferens; y, prostate; z, suspensory 

 ligament of the penis. 



pastage through the stomach and small intestine, escapes the absorbent action 

 of the villi and accumulates in the Cfecum, into which it may be said to wash 

 the alimentary mass it comes in contact with ; it thus dissolves the soluble 

 and assimilable matters this mass may yet contain, and so favours their entrance 

 into the circulation, through the immense absorbing surface formed by the 

 mucous membrane of the large intestine. 



The aliment undergoes still further change, and digestion is completed in 

 this viscus, principally in the Herbivora. 



B. Colon. 

 The colon is divided into two portions, which differ from each other in 



