PEYER'S GLANDS. 307 



of the same essential parts as the intestinal mucous mem- 

 brane, viz., a fine structureless memlrana propria, or base- 

 ment membrane, a layer of cylindrical epithelium lining 

 it and capillary blood-vessels covering its exterior. Their 

 contents appear to vary, even in health ; the varieties 

 being dependent, probably, on the period of time in rela- 

 tion to digestion at which they are examined. At the 

 bottom of the follicle, the contents usually consist of a 

 granular material, in which a few cytoblasts or. nuclei 

 are imbedded; these cytoblasts, as they ascend towards 

 the surface, are supposed to be gradually developed into 

 nucleated cells, some of which are discharged into the 

 intestinal cavity. The purpose served by the material 

 secreted by these glands is still doubtful. Their large 

 number and the extent of surface occupied by them, seem, 

 however, to indicate that they are concerned in other and 

 higher offices than the mere production of fluid to moisten 

 the surface of the mucous membrane, although, doubtless, 

 this is one of their functions. 



The glands of Peyer occur exclusively in the small intes- 

 Fig. 74.* 



tine. They are found in greatest abundance in the lower 

 part of the ileum near to the ileo-ceecal valve. They are 



* Fig. 74. Agminate follicles, or Peyer's patch, in a state of dis- 

 tension : magnified about 5 diameters (after Boehm). 



