240 



INTESTINAL DIGESTION. 



cous membrane, except that they are placed more irregularly and are not so 



abundant. 



The follicles which form the patches of Peyer are completely closed and 



are somewhat pear-shaped, with their pointed projections directed toward 



the cavity of the intestine. Just above the fol- 

 licle, there generally is a small opening in the 

 mucous membrane, surrounded by a ring of in- 

 testinal tubules, and leading to a cavity, the base 

 of which is convex and is formed by the coni- 

 cal projection of the follicle. The diameter of 

 the follicles is -fa fo -fa or fa of an inch (0-34 to 

 1 or 2 mm.) The small follicles generally are 

 covered by mucous membrane and have no open- 

 ing leading to them. Each follicle consists of 

 a rather strong capsule composed of an almost 

 homogeneous or slightly fibrous membrane, en- 

 closing a semi-fluid, grayish substance, cells, 

 blood-vessels and possibly lymphatics. The 

 semi-fluid matter is of an albuminoid character 



The cells * TCI 7 small > unded, and mingled 

 ; s, 3, grooves with small, free nuclei. The blood-vessels have 



; 4, 4, fossettes 



between some of the folds ; 5, 5, rather a peculiar arrangement. In the nrst place 



5, 5, 5, 5, 5, 5, valvulae conniven- 



tes ; 6, e, 6, 6. solitary glands ; 7, they are distributed between the lollicles, so as 



7, 7, 7. smaller solitary glands ; . , . , 



8, 8, solitary glands upon the vai- to form a rich net-work surrounding each one. 



Capillary branches are sent from these vessels 



into the interior of the follicle, returning in the form of loops. Lymphatic 

 vessels have not been distinctly shown within the investing membrane. 

 They have been demonstrated surrounding the follicles, but it is still doubt- 

 ful whether they exist in their interior. All _ _ 

 that is known is that during digestion, the 

 number of lacteals coming from the Peyerian 

 patches is greater than in other parts of the 

 mucous membrane ; but vessels containing a 

 milky fluid are never seen within the follicles. 

 The description of the follicles which com- 

 pose the patches of Peyer answers, in general 

 terms, for the solitary glands, except that the 

 latter are found in both the small and large 

 intestines. 



seen on the surface 



between the folds 



INTESTINAL JUICE. 



l 



Of the three fluids with which the food is 



brought in contact in the intestinal canal, FlG - 



namely, the bile, the pancreatic juice and the i, i, serous coat of the intestine ; 2, 2 2, 



2, serous coat removed to show the 

 patch ; 3, 3, fibrous coat of the in- 

 testine ; 4, 4, patch ; 5, 5, 5, 5, 5, 5, 5, 



*' 



intestinal juice, the last, the secretion of the 

 mucous membrane of the small intestine, pre- 



5, valvulas conniventes. 



