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An Intracellular Toxin of the Typhoid Bacillus. 



Accordingly the first step in the search for the body in question 

 consisted in substituting for the usual broth and peptone media,.- 

 culture fluids approaching more nearly in constitution the natural 

 body soils which clinically support the growth of the bacillus. For 

 this purpose, the organism was grown on the actual intracellular 

 juices of the following organs and tissues obtained in a fresh condi- 

 tion from the ox or calf : — - 



Intestinal mucous membrane, mesenteric lymphatic glands and 

 spleen. In each case the intracellular juice was brought to the requi- 

 site degree of alkalinity and used as a culture soil under the following 

 conditions : — 



1. Aerobically. 2. Anaerobic-ally. 3. With addition of normal 

 human serum. 4. After heating to 55" C. for 20 minutes. 



After from 4 to 6 weeks' growth the organisms were filtered off and 

 the filtrate tested for toxicity in guinea-pigs. With the possible- 

 exception of one spleen juice, none of the fluids thus obtained ex- 

 hibited any acute toxic power. It thus became necessary to search 

 within the typhoid organism itself for the missing toxin. For this 

 purpose the organisms were grown on ordinary beef broth agar, and 

 after careful washing with distilled water were disintegrated in a 

 mechanical contrivance at the temperature of liquid air (-180" C.) 

 This course was taken to satisfy the conditions that — (1) No chemical 

 change should take place during the disintegration, and (2) The 

 organisms could be disintegrated alone, without the addition of any- 

 triturating substance, the necessary subsequent removal of which 

 might vitiate the composition of the resulting mass. If such a dis- 

 integrated mass be freed from whole bacilli (if present) and from other 

 suspended insoluble particles by centrifugalisation, an opalescent fluid 

 results, which on inoculation into animals in small doses invariably 

 proves toxic or fatal. It is therefore concluded that the typhoid 

 bacillus contains within itself an intracellular toxin. 



The typhoid cell juices obtained by the above method are being- 

 examined for immunising and other properties at the Jenner Institute- 

 of Preventive Medicine, where the above investigations have been, 

 conducted. 



