PEYEE'S GLANDS. 



847 



tissue, spread through the cavity of each capsule among its semifluid contents, 

 and are disposed principally in lines converging to the centre. In some 

 subjects these small capsules are found almost empty, and then they are 



Fig. 591 B. 



Fig. 591 B. ENLARGED VIEW OF A 

 PART OF A PATCH OF PETER'S GLANDS 

 (from Boehm). V 



The shaded part of the figure shows 

 the surface of the intestinal mucous 

 membrane in the vicinity of the patch 

 occupied by villi, and between them the 

 orifices of the crypts of Lieberkiihn ; the 

 lighter part of the figure, in which about 

 a dozen of Peyer's vesicles may be seen, 

 is also beset with villi, and in this part 

 the crypts of Lieberkiihn are arranged 

 chiefly in circles round the vesicles. 



difficult of detection. They are 

 usually entirely closed ; but the 

 elder Krause observed 'that in the 

 pig they were occasionally open, 

 and a similar observation was 

 made by Allen Thomson, not only 

 in the pig, but in the human intestine also. 



The lacteal plexuses, which are abundant in the whole extent of the in- 

 testine, are especially rich and composed of wide vessels, where they 



EDHKJH - j 



Fig. 592. 





Fig. 592 TRANSVERSE SEC- 

 TION OF INJECTED PETER'S 

 GLANDS (from Kolliker). 



The drawing was taken 

 from a preparation made by 

 Frey : it represents the fine 

 capillary network spreading 

 from the surrounding blood- 

 vessels into the interior of 

 three Peyer's capsules from 

 the intestine of the rabbit. 



surround the closed fol- 

 licles, so closely indeed 

 that these may be said to 

 be imbedded in them ; 

 but the lacteuls do not 

 penetrate the capsules as 

 the capillary blood-ves- 

 sels do. 



It was formerly pre- 

 sumed without question 

 that Peyer's and the other 



closed follicles in the alimentary tract constituted a peculiar capsularform of secreting 

 glands ; but since the discovery of capillaries in their interior, and of the rich supply of 

 absorbents around them, it has been supposed that they might be more immediately 

 connected with the lymphatic system. This, however, is by no means proved ; for, 

 although the interior of the capsules can no longer be compared with the cavities of 



