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METHODS OF IDENTIFICATION AND STUDY 



Toxins. 



Prepare flask cultivations of the organism under 

 observation in glucose formate broth, and incubate for 

 fourteen days under optimum conditions. 



(a) Intracellular or Insoluble Toxins : 



1. Heat the fluid culture in a water-bath at 60 C. 

 for thirty minutes. (The resulting sterile, turbid fluid 

 is often spoken of as " killed" culture,) 



2. Inoculate a tube of sterile bouillon with a similar 

 quantity, and incubate under optimum conditions. 

 This "control" then serves to demonstrate the freedom 

 of the toxin from living bacteria. 



FIG. 160. Apparatus arrange for toxin filtration. 



3. Inject intraveneously that amount of the culti- 

 vation corresponding to i per cent, of the body- weight 

 of the selected animal, usually one of the small rodents. 



4. Observe during life or until the completion of 

 twenty-eight days, and in the event of death occurring 

 during that period, make a complete post-mortem ex- 

 amination. 



5. Repeat the experiment at least once. In the 

 event of a positive result estimate the minimal lethal 

 dose of "killed" culture for each of the species of 

 animals experimented upon. 



(b) Extracellular or Soluble Toxins : 



