ORGANS OF DIGESTION. 



119 



barely apparent to the naked eye, projecting into the lumen 

 for the purpose of absorbing the nutriment from the chyle_ 

 They consist of a covering of columnar epithelial cells (Fig. 

 65), within which ends a chyle vessel or lacteal surrounded 

 by small blood-vessels held in place by connective tissue. 

 The fatty portions of the food are carried by the lacteals 

 (Fig. 65^) to the left thoracic duct,, and thence to the jugu- 

 lar vein, while other portions of the food are taken up by 

 the capillaries of the portal system, which begin in the villi 

 (Fig. 65). The mucous membrane of the large intestine 



FIG. 64. CROSS-SECTION 

 OF THE SMALL INTES- 

 TINE. X 5. 



ex, Longitudinal muscu- 

 lar coat ; m, circular 

 muscular coat ; mu, 

 mucous coat ; Ib, glands 

 of Lieberkuhn ; se, 

 serous or peritoneal 

 coat ; sm, submucous 

 or areolar coat. 



FIG. 6$a. DIAGRAM OF A SMALL CUBE CUT 

 FROM THE WALL OF THE JEJUNUM. 



a, Mouth of intestinal or Lieberkuhn's 

 glands ; b, one of the nine villi cut open 

 showing the network of capillaries and 

 central white lacteal within; e, lacteal; 

 i, intestinal glands; m, artery; v, vein; 

 / and t, muscular coats. 



likewise contains tube-like glands similar to the glands of 

 Lieberkuhn, but no villi. 



