152 NORMAL HISTOLOGY. 



shaped, and frequently project somewhat into the 

 intestinal cavity. Where they lie, the tubular 

 glands are crowded to one side, and the villi are 

 absent over their surfaces. They may lie so near 

 the surface as to be covered only by a single layer 

 of cylindrical epithelium, or they may be more 

 deeply placed, and covered, in addition, by a thin 

 layer of the connective tissue of the mucosa. 

 They consist of a mass of recticular connective 

 tissue, whose meshes are somewhat narrower at the 

 periphery, where it becomes continuous with ad- 

 jacent parts. The meshes are closely filled with 

 small spheroidal cells, having the characters of 

 lymph-cells. In their periphery the lymph-vessels 

 of the mucous membrane form a closely anastomos- 

 ing network. The blood-vessels also interlace in 

 their periphery, and send an abundance of anas- 

 tomosing capillary loops into their interior. 



2. Peyer s Patches. These are found chiefly in the 

 small intestine, and here are most abundant in the 

 lower portion of the jejunum and in the ileum ; 

 they are round, or more frequently elongated, 

 usually slightly elevated structures, and are always 

 situated at the side opposite the mesenteric attach- 

 ment, with their long axes parallel with the axis of 

 the gut. They consist, essentially, of an aggregation 

 of a variable number of structures, having the char- 

 acters of the solitary nodule ; these are placed closely 

 together, side by side, and supplied in essentially the 



