NORMAL HISTOLOGY. 





FIG. 212. 



or by means of the orifices of the follicles between the bases of the 

 surrounding villi. The glands, owing to the rapid branching of their 

 tubules, more closely approach the racemose type than the compound 



tubular to which they 

 really belong, as shown 

 in their direct deriva- 

 tion from the .com- 

 pound tubular pyloric 

 crypts. The secretion 

 of these duodenal 

 glands' is mucous and 

 not serous, as shown 

 by the investigations 

 of Bensley. 



The solitary 

 glands are isolated 

 lymph - follicles scat- 

 tered through the 

 entire intestine ; they 

 are, however, most 



abundant in the lower part of the ileum and in the first portions of the 

 large intestine. They are situated primarily within the mucosa, al- 

 though they frequently lie also within the submucous coat ; when well 



Section of human large intestine, containing solitary gland : a, 

 mucosa ; b, submucosa ; c, c', circular and longitudinal layers of 

 muscle ; d, serous coat. 



FIG. 213. 



Section of small intestine of cat, showing a Peyer's patch (d, d) cut crosswise : a, b, c, respectively 

 mucous, submucous, and muscular coats. 



developed, they encroach upon the mucosa to such an extent that their 

 inner pole slightly projects upon the free surface of the intestine. The 

 lymphoid tissue is somewhat denser in the periphery of the fol- 

 licle, beneath its limiting capsule, than towards the centre ; but the 



