SMALL INTESTINE 



159 



In the center of each villus is the blind tube G, G, a part of the 

 lymphatic system, and here called a lacteal. When, during diges- 

 tion, the minute globules of fatty food reach the small intestine, 

 they are grasped by the epithelial cells covering the villi, and ar* 

 carried eventually within the body of the villus to this lacteal. 



The lacteals pierce the muscularis mucosae, and in the submu- 

 cosa are in connection with a plexus of lymphatic tubes and spaces. 

 They eventually unite with efferent lympli- tubes, J, which open 

 into the lymphatics of the mesentery. 



Connected with the plexus of lymphatics in the submucosa are 

 minute nodules of lymphoid or adenoid tissue, which have unfortu- 

 nately been called lymphatic glands. They are in no sense glands. 



D- 



FIG. 105. DIAGRAM SHOWING PORTIONS OP INTESTINAL Mucous MEMBRANE CON- 

 CERNED IN ABSORPTION. 



A. Mucosa. 



B. Muscularis mucosae. 



C. Submucosa. 



D. D. Villi. 



F, F. Crypts of Lieberkiihn. 



G, G. Lacteals. 



H, H. Chinks arid intercommunicating channels of the lymph-plexus of the submucosa. 

 I. Bottom of a mass of adenoid or lymphoid tissue a so-called solitary gland. Peyer's 

 patches are formed of aggregations of these nodules. 

 J. Efferent lacteal or lymph duct. 



Slit up a portion of intestine along the attached border, and 

 carefully examine the inner surface : it will present a velvety 

 appearance, due to the minute villi. You will also find little 

 nodules, perhaps one or two millimeters in diameter, scattered here 



