CHAPTER XIII. 



Mode of Ingestion of Bacteria by the Sub- 

 epithelial Lymphatic Glands. 



It has already been pointed out that the subepithelial 

 differ from all other varieties of lymphatic glands by 

 the total absence of afferent lymphatic channels. In 

 the ordinary interstitial lymphatic glands the definite 

 nodules of lymphoid tissue lie beneath the capsule and 

 receive the entering lymph. In a subepithelial lymph- 

 atic gland these same nodules are directly beneath the 

 epithelium, upon which they encroach. Instead of 

 receiving lymph from the tissues these nodules welcome 

 bacteria and possibly toxins from the adjacent lumen 

 of the alimentary canal. The passage of toxins would 

 be easy to understand. All the nourishment of the 

 body has to pass through the intestinal mucous mem- 

 brane. The passage of bacteria through healthy 

 epithelium fits in less readily with our general con- 

 ceptions, but that bacteria similar to those in the ali- 

 mentary lumen do occur in immense numbers in the 

 subepithelial lymph nodes has been conclusively shown 

 in the preceding chapter. But I have repeatedly ex- 

 amined sections of the alimentary wall without finding 

 bacteria save in the subepithelial lymphatic glands. 



Attention has been drawn to the fact that the posi- 

 tion and structure of many of the subepithelial glands 



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