

METHOD OF OBTAINING INTESTINAL SECRETION. 



FIG. 79. 



187 



These intestinal follicles be- 

 long to a very simple form of 

 gland, each one being a single 

 straight depression in the mu- 

 cous membrane not deep enough 

 to deserve the name of a tube. 

 In the small intestine they are 

 set as closely as the villi permit. 

 In the large intestine, where the 

 villi are absent, they are more 

 closely set and are also deeper 

 (Fig. 78). They are bounded 

 by a thin basement membrane 

 which is embraced by a close 

 capillary network of blood ves- 

 sels, and are lined by a single 

 layer of cylindrical or spherical 

 epithelial cells. 



The epithelial covering of the 

 processes known as villi, which 

 are studded all over the mucous 

 membrane of the small intestine, 

 produce some mucus. 



Method of Obtaining 

 Intestinal Secretion. Con- 

 siderable difficulty has been 

 found in obtaining the proper 

 intestinal juice free from admix- 

 ture with the secretions of the 

 liver and pancreas which are 

 carried along and mixed with 

 it. A short portion of the small 

 intestine has, however, been suc- 

 cessfully isolated from the rest 

 without injuring the mesentery 

 or its blood vessels. One of the 



extremities Of the isolated por- Villus with the capillaries injected showing 

 MTQO .11 * -nA 4-U^. 4-U their close relation to epithelium, some of 

 Was Closed, and the Other the cells of which are distended with mucus. 



(Cadiat.) 



