426 BACTERIOLOGY. 



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 tempera- 

 ture 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 

 conspicuous ? 



Should any of the animals survive the inoculations 

 made from the different cultures in the foregoing ex- 

 periment, 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 cul- 

 ture 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 incubators act in the same way toward ani- 

 mals as the organisms growing in the flasks ? Is the 

 action of each of these cultures the same for mice, 

 guinea-pigs, and rabbits ? 



Prepare a 2 per cent, solution of sulphuric acid in 

 distilled water; suspend in this a number of anthrax 

 spores; at the end of three, six, and nine days at 35 C. 

 inoculate both a guinea-pig and a rabbit. Prepare cul- 

 tures from this suspension on the third, sixth, and ninth 

 days; when the cultures have developed inoculate a 



