INTESTINAL DIGESTION. 229 



and between them are seen numerous foramina, which are 

 the openings of tubular glands, known as the crypts of 

 Lieberkuehn. 



In addition to the tubular glands, by dissecting, from 

 without, the muscular from the mucous coat, lining the com- 

 mencement of the duodenum, we find clusters of vesicles 

 similar to the vesicular structure of the salivary and pan- 

 creatic glands. These form distinct layers provided with 

 ducts which open on the free surface of the membrane ; and 

 Dr Todd states that Brunner's glands, or, as he calls them, 

 the duodenal, are more developed in the horse than in any 

 other animal he has hitherto examined them in. 



Fig. 91. Portions of dog's intestine, showing the glands of Crunner, enlarged five 

 times. BERNARD. 



i i. mucous lining of the intestine; g g g, glands of Brunner; bbb, glandular layer be- 

 neath the muscular coat ; m m, muscular coat; p p, peritoneal coat; c, cellular tissue, 

 which separates the glandular from the muscular layers. 



We have next to treat of the solitary glands glaiidulae 

 solitariae peculiar and rather scanty bodies, visible at various 

 parts of the small intestine. These are vesicular, and without 

 any opening when in the perfect state, surrounded by villous 

 processes and Lieberkuehnian follicles. Some of the villi 

 also project from the surface of the so-called glands, which 

 are most apparent when distended with secretion. 



About the second half of the jejunum, and along the 

 whole of the ileum, we see longitudinal patches, varying from 

 half an inch to even three inches in length, scattered all over, 

 but more especially situated near the superior or attached 



