TYPHOID FEVER. 261 



gas-production is developed, which is unknown to the 

 typhoid bacillus. 



Finally, the typhoid bacillus does not produce indol, 

 but the addition of potassium nitrite and sulphuric acid 

 to bouillon cultures of the colon bacillus invariably brings 

 about the rose color which characterizes this product. 



Not only are the morphological and vegetative similar- 

 ities of these organisms great, but their pathogeny bears 

 many points of resemblance. The open lymphatics and 

 vessels of the intestinal ulcers of typhoid favor the ab- 

 sorption of the bacteria in the digestive tract, and the 

 colon bacillus enters the blood no longer to be a sapro- 

 phyte, but now to be a virulent pus-producer, and in 

 many cases of typhoid we find suppurations and other 

 milder inflammations due to this microbe. This is also 

 a stumbling-block, for the typhoid bacillus when dis- 

 tributed through the blood may act in exactly the same 

 manner. 



The typhoid bacillus may enter the body, at times, 

 through dust (Klemperer and Levy), but no doubt, in the 

 great majority of cases, enters the digestive tract at once 

 through the mouth. It may possibly enter through the 

 rectum at times, as illustrated by the mention which 

 Eichhorst makes of the infection of soldiers in military 

 barracks through the wearing of drawers previously worn 

 by comrades who had suffered from typhoid. 



When ingested the resisting power of the bacillus per- 

 mits it to pass uninjured through the acid secretions of 

 the stomach and to enter the intestine, where the chief 

 local disturbances are set up. 



The bacilli enter the solitary glands and Peyer's patches, 

 and multiply slowly during the one to three weeks of the 

 incubation of the disease. The immediate result of their 

 residence in these lymphatic structures is increase in the 

 number of cells, and ultimately the necrosis and slough- 

 ing which cause the typical post-mortem lesion. From 

 the intestinal lymphatics the bacilli pass, in all probabil- 

 ity, to the mesenteric glands, which become enlarged and 



