Microscopic Study of Cultures 



215 



secure pure cultures of the bacillus from the unmixed infectious 

 lesions. 



In^other cases, as when it is desired to isolate Micrococcus tetra- 

 genus, the pneumococcus, and other bacteria that pervade the blood, 



Fig. 54. — Modern incubating oven. 



it is easier to inoculate the animal most susceptible to the infection 

 and recover it from the blood or organs, than to plate it out and 

 search for the colony among many others similar to it. 



Microscopic Study of Cultures. — Some attention has been given 

 to the preparation of microtome sections of gelatin cultures, though 



