STUDY OF BACTERIAL CULTURES 115 



PHYSIOLOGICAL CHARACTERS 



It is customary to determine gas and acid production in car- 

 bohydrate media, development of ammonia, reduction of nitrates 

 to nitrites, indol production, temperature relations, including 

 optimum growth temperature and thermal death-point, resistance 

 to desiccation and disinfectants, and pathogenic characters. The 

 methods of study of these characters have already been discussed. 



