422 



MANUAL OF HISTOLOGY. 



loosely woven follicles are observed to lie. This condition of parts may 

 be seen in the tonsils and conjunctival follicles. 



i. 



Fig. 414. Vertical section of one of Peyer's patches from the human being, injected through the 

 lymphatics, a. villi with their absorbent radicles; b, glands of Lieberkiihn; c, muscular coat of 

 the mucous membrane; d, cupola of follicle; e, mesial zone; /, base; g, passage of the chyle-radicles 

 of the villi into the true mucous membrane; h, reticulated arrangement of the absorbents about the 

 mesial zone; i, course of the latter at the bases of the follicles; and k, their confluence to form the 

 lymphatics of the submucosa; I, follicular tissue of the latter. 



When this arrangement prevails the investing spaces cannot be said to 

 be entirely wanting, they are rather converted into a system of narrow 

 passages, which interlace upon the surface of the follicle " like the net 

 upon the surface of a child's toy Indian rubber ball." 



The view that holds these passages around the follicle to be lymphatic 

 canals is shown to be correct by injection (fig. 415). We observe that, 

 from the surface of the mucous membrane, and mostly from the neigh- 

 bourhood of the follicle generally, e.g., in many of Pei/er's patches, from 

 the adjacent villi ffig. 414, ) ; and in the case of the conjunctival 



follicles from the mucous mem- 

 brane, especially on the surface 

 of the band of union (fig. 415, c) ; 

 that lymphatic vessels which 

 take the place of the vas afferens 

 of the nodes are conducted to 

 the surface of the follicle, either 

 simply (fig. 415), or with a certain 

 amount of complex interlacement 

 (fig. 414, (J). Arrived here, they 

 open into either the investing 

 space or its retiform equivalent 

 (fig. 414, A, i; 415, c). 



Those submucous lymphatic 

 vessels, which take on such a 

 variety of forms (fig. 414, k; 415, a), are the conduits corresponding to 

 the vasa efferentia of the lymph nodes; in short, the parallel between these 



Fig. 415. Trachoma gland from the ox in vertical 

 section and with injected lymphatic canals, a, sub- 

 mucous lymphatic vessel ; c, distribution of the 

 same to the passages of the follicle b. 



