108 IMMUNITY IN HEALTH 



(2) Whether a higher degree of immunity could be 

 produced more rapidly by injection into the appendi- 

 cular than into the jejunal sinus. 



Until such investigations can be made -the hypothesis 

 can only be tentatively accepted. On the other hand 

 the ingestion of bacteria by the subepithelial lymphatic 

 glands is a firmly established fact, and it is hardly 

 possible for this wholesale ingestion to proceed con- 

 tinuously without enhancing the natural powers of 

 resistance. 



Another line of opposition may be taken by pointing 

 out that these subepithelial lymphatic glands can be 

 obliterated without apparent harm resulting. Tonsils, 

 adenoids and vermiform appendix have been removed 

 in countless instances and few, if any, ill effects have 

 been discerned. (See pages 94, 95 and 96, however.) 

 These same glands are often so destroyed by suppuration 

 or fibrosis that the lymphoid tissue eventually becomes 

 practically non-existent. And all the subepithelial 

 lymphoid tissue diminishes in quantity after puberty. 

 Further the various collections of subepithelial lym- 

 phoid tissue are absent in a few of the higher and most 

 of the lower types of animals. To all of which it may 

 be replied that an animal can still live when one eye is 

 removed, some animals exist without eyes at all, many 

 successful people's eyesight is defective ; yet we cannot 

 say that the eye has no useful function. 



