CHANGES IN INTESTINAL LYMPH NODES. 439 



The greatest changes take place in the organs 

 (lymphoid) which contain the bacilli most con- 

 stantly and in the greatest numbers. It is here 

 that the toxic substance may be present in greatest 

 concentration, as a consequence of the continual 

 solution of the organisms. Mallory describes an 

 enormous hyperplasia of the endothelial cells, es- 

 pecially those of the lymphatic structures. The 

 cells are phagocytic, and especially in the lymphoid 

 tissue of the intestines and in the mesenteric 

 lymph glands, englobe and destroy the lymphoid 

 cells on a large scale. It seems probable that the 

 endothelial proliferation which has been described 

 is due to the rather mild but prolonged action of 

 the dissolved toxic constituents of the typhoid ba- 

 cillus; the condition is that of an inflammatory 

 hyperplasia. It has been suggested that the hypo- 

 leucocytosis of typhoid fever is due to the destruc- 

 tion of the lymphocytes in the lymphoid organs by 

 the endothelial phagocytes. 



The granular and fatty degenerations of the 

 parenchymatous organs do not differ from those 

 seen in many acute infections. 



The conditions in the intestinal tract would Mixed 

 seem to favor mixed infections, especially by the 

 colon bacillus and streptococcus, and the primary 

 infection probably decreases the resistance to sec- 

 ondary invasion. The role of the colon bacillus in 

 typhoid fever is perhaps not definitely established, 

 although it has been found in the circulation, in 

 abscesses, and in the urine in cases of cystitis ac- 

 companying the disease. The typhoid and colon 

 bacilli grow well together. A mixed general in- 

 fection with the streptococcus causes a grave sep- 

 tic condition characterized by an irregular tern- 



