524 BACTERIOLOGY. 



away the growth and carefully break it up in 10 c.c. 

 of sterilized physiological salt-solution. The more 

 thoroughly it is broken up the more accurate will be the 

 results of the experiment. Place this in a bath of boil- 

 ing water, and at the end of one, three, five, seven, and 

 ten minutes make plates upon agar-agar each 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 a bouillon culture from the blood of an ani- 

 mal 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 charac- 

 teristic ? 



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, 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 tempera- 



