322 



THE HUMAN BODY. 



outside the lacteals and beneath the muscular layer, is a close 

 network of blood-vessels. 



Opening on the surface of the small intestine, between 

 the bases of the villi, are small glands, the crypts of Lieber- 

 kiilm. Each is a simple unbranched tube lined by a layer 

 of columnar cells similar to that which covers the villi and 

 the surface of the mucous membrane between them. In 



FIG. 99. Villi of the small intestine; magnified about 80 diameters. In the 

 left-hand figure the lacteals, a, 6, c, are filled with white injection; d, blood-ves- 

 sels. In the right-hand figure the lacteals alone are represented, filled with a 

 dark injection. The epithelium covering the villi, and their muscular fibres, are 

 omitted. 



structure they greatly resemble the mucous glands of the 

 stomach (c, Fig. 97). In the duodenum are found other 

 minute glands, the fjlands of Brunner. They lie in the 

 submucous coat and send their ducts through the mucous, 

 membrane to open on its inner side. 



The Large Intestine (Fig. 103*), forming the final por- 

 tion of the alimentary canal, is about 1.5 meters (5 feet) 

 long, and varies in diameUi from about 6 to 4 centimeters 

 (2| to 1-J inches). Anatomists describe it as consisting of 

 the caecum with the vermiform appendix, the colon, and the 

 rectum. The small intestine does not open into the com- 

 mencement of the large but into its side, some distance 



