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 



