190 



ABSORPTION. 



Fig. 57. 



form or cylindrical villi, sometimes double or even triple in those of a 

 more flattened form. It has exceedingly thin walls, consisting only of 

 a single layer of flattened epithelium cells. 



Closed Follicles of the Small Intestine In addition to the secreting 

 glandules and villi, the intestine presents, throughout its extent, two 



sets of glandular looking organs, known 

 as the glandules solitariae and the 

 glandular agminatae. The first of these, 

 or the solitary glandules, are found in 

 the upper part of the intestine, scattered 

 at intervals over its surface, as minute 

 whitish points. Farther down they 

 begin to occur in clusters of several to- 

 gether, and in the lower part of the 

 jejunum and in the ileum they consti- 

 tute rounded or elongated oval patches, 

 from 1J to 5 centimetres in length, 

 known by the name of "Peyer's patches." 

 These patches are always situated op- 

 posite the attachment of the mesentery, 

 and with their long diameter parallel to 

 the axis of the intestine. 



The structure of the solitary gland- 

 ules and of those forming Peyer's 

 patches is the same. The only differ- 

 ference between them is that in one case 

 the follicles are distributed separately over the surface of the intestine, 

 while in the other they are collected into distinct groups. 



Each follicle is a rounded or 



Fig. 58. ovoid body, from one-half to two 



millimetres in diameter, situated 

 partly in the thickness of the 

 mucous membrane, and partly 

 below. It consists of an ex- 

 ternal investing capsule, closed 

 on all sides, from the inner sur- 

 face of which slender anastomos- 

 ing filaments pass through the 

 substance of the organ, forming 

 a delicate scaffolding or frame- 

 work of minute fibres. In the 

 interstices between these fibres 

 there is a small quantity of fluid, 

 together with an abundance of 



O 



OF THE CLOSED FOLLICLES OP PET- lymph corpuscles, or faintly 



ER'S PATCHES, from Small Intestine of Pig, ffranu l ar cells about 13 mmm. 

 showing the bloodvessels in its interior. Magni- . 



fled 60 diameters. in diameter. The follicle is also 



FK visit's PATCH of 

 glandules from the ileum. 



nominated 

 (Boehm.) 



