BACTERIUM ANTHRACIS 571 



Prepare a bouillon culture from the blood of an animal 

 just dead of anthrax. 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 the blood of an 

 animal just dead of anthrax. 



Place these flasks in the incubator at a temperature of 

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

 or more days remove a flask. Label each flask as it is 

 taken from the incubator with the exact number of days 

 that it has been at the temperature of 42.5 C. Study each 

 flask carefully, both in its culture-peculiarities and in 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 con- 

 spicuous? 



Should any of the animals survive the inoculations made 

 from the different cultures in the foregoing experiment, 

 note carefully which one it is, and after ten to twelve days 

 repeat the inoculation, using the same culture; if it again 

 survives, inoculate it with the culture preceding the one 

 just used in the order of removal from the incubator; if 

 it still survives, inoculate it with virulent anthrax. What is 

 the result? How is the result to be explained? Do the 

 cultures which were made from these flasks at the time of 

 their removal from the incubator act in the same way toward 



