PETER'S GLANDS. 309 



degree in which it is developed, either sunk beneath, or 

 more or less prominently raised on, the surface of a 

 depression or fossa in the mucous membrane. Each gland 

 is surrounded by openings like those of Lieberkuhn's 

 follicles (see fig. 76) except that they are more elongated ; and 

 the direction of the long diameter of each opening is such 

 that the whole produce a radiated appearance around the 

 white sacculus. These openings appear to belong to tubules 

 identical with Lieberkiihn's follicles : they have no commu- 

 nication with the sacculus, and none of its contents escape 

 through them on pressure. F - ,. * 



Neither can any perma- 

 nent opening be detected 

 in the sacculus or Peyer's 

 gland itself (see fig. 77). 



Each gland is a closed 

 sac or follicle formed of a 

 tolerably firm membranous 

 capsule of imperfectly de- 

 veloped connective tissue, 

 imbedded in a rich plexus 

 of minute blood-vessels, 

 many fine branches from a 



which pass through the capsule and enter, chiefly loopwise, 

 the interior of the follicle (fig. 78). The contents of each 

 sac amid which these minute vessels are distributed, con- 

 sist of a pale greyish opalescent pulp, formed of albu- 

 minous and fatty matter, and a multitude of nucleated 

 cells of various sizes, many of which, according to Kolliker, 

 exhibit well-marked endogenous cell-multiplication. 



*' Fig. 77. Side-view of a portion of intestinal mucous membrane of 

 a cat, showing a Peyer's gland (a) : it is imbedded in the submucous 

 tissue (/), the line of separation between which and the mucous mem- 

 brane passes across the gland : b, one of the tubular follicles, the orifices 

 of which form the zone of openings around the gland : c, the fossa in 

 the mucous membrane : d, villi : e, follicles of Lieberkuhn (after Bendz). 



