Chap, xxv.j SMALL AND LARGE INTESTINE. 205 



internal free surface of the latter (Fig. 120). These 

 are the solitary lymph follicles of the small and large 

 intestine ; in the latter they are larger than in the 

 former. 



Agminated glands, or Peyer's glands, are larger or 

 smaller groups of lymph follicles, more or less fused 



a 





Fig. 120. From a Section through a part of a Human Payer's Patch, 

 showing the distribution of the Lymphatic Vessels in the Mucosa 

 and Snbmucosa. 



a, Vi Hi, with central chyle vessel ; 6, Lieberkiihn's crypts ; c, region of muscularis 

 mucosifi; /, lymph follicle; g, network of Lymphatics around the lymph 

 follicle; I, lymphatic network of thj submucosa; *, an efferent lymphatic 

 trunk. (Frey.) 



with one another, and situated with their main part 

 in the submucosa, but extending with their summit 

 to the epithelium of the free surface of the mucosa. 

 In the lower part of the ileum these Peyer's glands 

 are very numerous. The epithelium covering the 

 summits of these lymph follicles is invaded by, and 

 more or less replaced by, the lymph corpuscles of the 



