THE INTESTINAL ORGANS. 127 



■descending downward and backward to the left flank, where it 

 becomes the jejunum, the ileum being the portion suspended in 

 the left flank which terminates at its junction with the large gut 

 ■called the caecum. 



"Cbc Large Intcattnca 



Are divided into three divisions. 1. The Caecum. 2. 

 The Colon. 3. The Rectum. 



The caecum is a vast reservoir in the form of a cul-de-sac. 

 It is nearly cylindrical in form without bulgings or longitudinal 

 bands; its extremity is rounded and globular, floating freely in 

 the cavity of the abdomen and directed backwards. The ileum 

 joins the caecum by piercing the latter at right angles at its 

 siiperior extremity, the internal mucous membrane of the ileum 

 forming a valve permitting the passage of material to the 

 caecum, but effectually preventing its return. The caecum 

 serves as a reservoir for the enormous quantity of fluid ingested 

 by herbivorous animals, which in its rapid course through the 

 stomachs and small intestines is not absorbed by the villi or 

 mucous projections in the bowels. The fluids accumulate in 

 this gut, and by their solvent properties on the matter contained 

 in it favor their entrance into the circulation through the large 

 expanse of absorbing surface which the mucous membrane of 

 the gut presents. It is in this viscus that digestion is virtually 

 completed in herbivorous animals. The colon commences 

 from an opening situated above the entrance of the ileum to the 

 caecum. In calibre it at first equals the caecum, but soon be- 

 comes constricted, maintaining a uniform diameter, which, for 

 about eight feet in length, is nearly treble the diameter of the 

 small intestines; then the gut decreases in size to the same 

 calibre as that of the small intestines, continuing so for aboiit 

 nine feet in length, when it again increases in size about one foot 

 prior to its termination, this latter part being termed the rectum. 



