SECT. 



I55-! 



peyer's glands. 



333 



A -'S- 



Fig. 143 







m 



1 



A particle of a Feyerian gland, 

 from an old man; after Flouch. 

 a. Follicles surrounded by the 

 openings of the Lieberkuhnian 

 glands ; 6. villi ; c. more isolated 

 openings of Lieberkuhnian glands. 



Fig. 144. 



which is here somewhat more firmly adherent to the mucous 

 membrane. 



When viewed from the cavity of the intestine, the patches present, 

 very conspicuously in man, numerous small 

 depressions, i"' to \'" to i'" apart from 

 each other. These depressions correspond 

 to the individual follicles, and their bot- 

 tom is slightly protruded upwards by the 

 latter, but they never support any villi. 

 The remaining portion of the patch is occu- 

 pied by ordinary villi, or reticulated folds, 

 and apertures of Lieberkuhnian glands, 

 which latter are arranged in a circlet, of 

 6 to 10 and more apertures, around the 

 slight elevations occasioned by the follicles, the corona tubulorum 

 of authors. 



Every follicle of a patch consists of a completely closed, thick, 

 tolerably firm envelope of an in- 

 distinctly fibrous areolar tissue 

 with interspersed nuclei, and soft, 

 mostly greyish (never milk-white) 

 contents, which are slowly dif- 

 f usable in water, and composed 

 of a certain amount of fluid and 

 innumerable nuclei and round 

 cells, o - oo4-"' to o # oo8"' in diame- 

 ter. These cells, when recent, 

 appear perfectly homogeneous 

 and dull grey ; they become clear 

 on the addition of water or acetic 

 acid, and then disappear; whilst 

 the nuclei become, at the same 

 time, granular, and come very distinctly into view. Amongst these 

 elements, which also occasionally contain fat in the form of 

 granules, and, as shown by comparison of the different forms, are 

 continually undergoing the process of formation and dissolution, 

 there exist, as Frei and Ernst have discovered in animals, and 

 as I have found also in man, numerous but very fine blood- 

 vessels, 00015'" to 0004'" in diameter, which are connected 

 with a rich vascular network surrounding the follicle, and in 

 animals, as e. g. the pig, can even be recognised with facility in 



Horizontal section from the middle of three 

 Peyerian capsules of the rabbit, to show the 

 vessels in their interior. After an injection 

 of Frei. 



