THE ALIMENTARY CANAL 



367 



of their constituent nodules is variable, frequently they contain as many 

 as fifteen or twenty. Each of these nodules is usually invested by a thin 

 fibrous capsule, though frequently they are confluent with one another. 



FIG. 342. THE CENTRAL PORTION OP A PEYER'S PATCH IN THE ILEUM OF A DOG'S 

 INTESTINE. 



a, villi; b, glands; c, lymph nodules, an agminated follicle; d, connective tissue of 

 the submucosa; e, a portion of the muscular coat. Hematein and eosin. Photo. 

 X 35. 



The long axes of the ovoid nodules exceed the average thickness of 

 the mucous membrane so that the patch forms a superficial elevation of 

 the mucosa and its deeper surface penetrates the muscularis mucosae 

 and enters the submucous coat. Hence occasional fragments of the mus- 

 cularis mucosEe often occur between the bases of the constituent nodules. 



