BACILLUS ANTHRACIS. 387 



upon agar-agar with one loopful of the contents of this 

 tube. Are the results on the plates alike ? 



Determine the exact time necessary to sterilize ob- 

 jects, such as silk or cotton threads, on which anthrax 

 spores have been dried, by the steam method and by the 

 hot-air method. 



Prepare from the blood of an animal just dead of an- 

 thrax a bouillon culture. After this has been in the 

 incubator for from three to four hours, subject it to a 

 temperature of 55 C. for ten minutes. At the end of 

 this time make plates from it, and also inoculate a rabbit 

 subcutaneously with it. What are the results ? Are the 

 colonies on the plates in every way characteristic ? 



Inoculate six Erlenmeyer flasks of sterile bouillon, 

 each containing about 35 c.c. of the medium, from either 

 the blood of an animal just dead of anthrax or from a 

 fresh virulent culture in which no spores are formed. 



Place these flasks in the incubator at a temperature of 

 42.5 C. At the end of five, ten, fifteen, twenty, twenty- 

 five, etc., days remove a flask. Label each flask as it is 

 taken from the incubator with the exact number of days 

 for which it had been at the temperature of 42.5 C. 

 Study each flask carefully, both in its cultural peculiar- 

 ities and its pathogenic properties when employed on 

 animals. 



Are these cultures identical in all respects with those 

 that have been kept at 37 C.? 



If they differ, in what respect is the difference most 

 conspicuous ? 



