186 



MANUAL OF PHYSIOLOGY. 



Brunner's glands form, in some animals, a dense layer in the 

 submucous tissue of the beginning of the duodenum ; they are 

 small branched saccular glands resembling mucous glands in 

 structure. Owing to their small size, the secretion cannot be ob- 

 tained in sufficient quantity to make satisfactory experiments in 

 respect to its properties. It is said to dissolve albumin and to 



FIG. 78. 



Section of the Mucous Membrane of small intestine, showing Lieberktthn's follicles 

 (a) with their irregular epithelium and the villi (6) passing out of view ; (c) Muscularis 

 mucosae; (d) Submucous tissue. (Cadiat.) 



have a diastatic fermentative action, so that probably the secre- 

 tion is analogous to that of the pancreas, as Brunner originally 

 supposed. The quantity of fluid secreted by these glands is so 

 small that its existence is not taken into account in speaking of 

 the intestinal juice, by which is meant the fluid poured out by 

 the innumerable short tubes or follicles of Lieberku'hn. 



