520 



I U I.I.I-TJX 167 



TABLE 48. ACID PRODUCTION OX CARBOHYDRATE BROTHS 



Nitrate reduction. — Cultures grown in nitrate broth were 

 tested for nitrites at the end of 5, to and 15 days, with uniformly 

 positive reaction. Other cultures were tested with Nessler's re- 

 agent for ammonia with negative results. 



Hydrogen sulphid. — Cultures on nutrient broth were tested 

 for hydrogen sulphid production by means of moist filter paper, 

 bearing lead acetate, suspended from the plug. No evidences of 

 this gas were observed. 



Indol production. — Cultures on Dunham's solution and on 

 peptone water were tested for indol production with negative 

 results. 



Temperature relations. — The optimum temperature was from 

 20 to 25 C. The maximum was slightly above 40 C. Growth 

 occurred at io° but not at 4 C. 



Thermal death point. — Thermal death point determinations 

 were made by exposing young transfers in thin wall test tubes at 

 various temperatures, in a constant water bath for ten minutes 



