ORGANS OF THE BODY. 



471 



1- 



Fig. 450. Tonsil of an adult (after Schmidt), a, large excretory 

 passage; 6, a simple one; c, lymphoid parietal stratum with 

 follicles; d, a lobule strongly resembling a lingual crypt ; e, a 

 superficial, /, a deeper mucous gland. 



tonsils, and as varied in the arrangement of their excretory ducts as those 

 of the lingual follicles. They discharge their contents, namely, either 

 into the caecal depression of the organ or free on the surface of the tonsil. 



The frequent inflammatory affections to which the amygdalae are subject 

 in adult human beings, render them rather dubious objects of research, 

 for which reason specimens obtained from young children should be 

 preferred. The ordinary arrangement of the openings in the adult was 

 found by Schmidt to be either a separate duct for each pit (fig. 450, b) or a 

 collection of the latter to form one large canal (a). The surface of the 

 organ presented the usual mucous membrane papillae, but the depression 

 only showed traces of them. He frequently encountered, also in the 

 immediate neighbour- 

 hood of the tonsils, a few 

 scattered crypts with lym- 

 phoid walls, in which 

 follicles were imbedded, 

 resembling greatly the 

 blind follicles of the 

 tongue (d). 



This extension, just 

 mentioned, of lymphoid 

 tissue from the fundus of 

 the crypt up to the under 

 surface of the epithelial 

 covering, may be readily seen in the tonsils and lingual follicles of the 

 calf. In some spots even this covering appears not to be completely 

 continuous throughout. Taking this arrangement of parts into con- 

 sideration, it does not seem unwarrantable to suppose that from out the 

 meshes of this superficial reticular tissue, lymph cells may be set 

 free, constituting, when surrounded by 

 the watery secretion of the mouth, 

 those saliva corpuscles so enigmatical as 

 to their origin. This view may be the 

 more safely accepted now that we are 

 acquainted with the amoeboid powers of 

 motion of the lymph cells ( 49). 



If the mucus welling from the orifices 

 on the tonsils of a newly killed calf be 

 examined, the abundance of saliva cor- 

 puscles to be met with there (Frey] will 

 strike every eye. 



The Hood-vessels (remarkable for the 

 number of highly developed veins among 

 them) form, with their ramifications, a 

 dense network of coarse and fine tubes, 

 which becomes more delicate as it ap- 

 proaches the surface, where it sends off loops into any papillae which may 

 be present. As soon as follicles commence to make their appearance in 

 this lymphoid layer, the vascular network is restricted to the smaller 

 space of the interfollicular connective-tissue, so that it becomes more 

 dense still. In the follicle itself, however, a very delicate network of 

 radially arranged capillaries is now to be seen, very similar to that already 

 encountered in the follicles of Peyer's patches. 

 31 * 



Fig. 451. Froin the tonsil of the pig. a, 

 depression in the mucous membrane; 

 6, lymphoid tissue; c, follicle; d, lym- 

 phatic vessel. 



