178 JOHN STEPHENS LATTA 



in a place of abundant blood supply, but as the nodule increases 

 in size, due to differentiation and proliferation, the capillaries 

 traversing the nodule become insufficient to nourish the larger 

 amount of lymphatic tissue. The cells nearer the periphery, 

 then, are better nourished than those more centrally located, be- 

 cause they receive nourishment also from blood vessels of the 

 tunica propria and the submucosa. Therefore, degenerations 

 are more numerous in the more centrally lying cells in a com- 

 pletely formed nodule. 



The relationship between the system of lymph vessels and the 

 nodules of lymphatic tissue in the intestinal tonsils is much the 

 same as the relationship between the nodules of lymphatic and 

 hemolymph nodes and the surrounding secondary sinuses. But 

 in the lymphatic nodes the lymph in the sinuses bathes the 

 lymphatic tissue directly, while there are no lymphatic sinuses 

 in connection with the intestinal nodes. Injection of the lym- 

 phatic vessels (Berlin blue gelatin mass) shows, however, that 

 there is a dense network of lymphatic capillaries just outside the 

 connective-tissue sheath of the nodule. This is, of course, part 

 of the submucosal plexus, which is, in turn, part of the system 

 for transportation of the chyle (Heuer, Sabin). No lymphatics 

 could be found penetrating the nodule in any case. 



Among the things which must be considered in an interpre- 

 tation of intestinal tonsillar tissue is the relationship existing 

 between the lymphatic tissue and the overlying epithelium. 

 Lymphatic nodules of the intestine do not remain restricted to 

 definite areas, but spread in all directions from the point of forma- 

 tion. Thus the tunica propria in villi directly over lymphatic 

 nodules become of infiltrated with lymphocytes to such an extent . 

 as to form enlarged 'lymphatic villi.' After a certain stage in 

 development (about fourteen days) has been reached, the lym- 

 phocytes begin to wander into the epithelium covering these 

 lymphatic villi. It is, doubtless, this close association between 

 the epithelium and the lymphatic tissue which led some of the 

 earlier authors (as Retterer and von Davidoff) to the belief in an 

 epithefial origin of these lymphocytes. Most authors, however, 

 consider the relationship between the lymphocytes and the 



