490 



AUGUSTO BONAZZI 



TABLE 6 



1 and 4 were inoculated with an active culture of the nitrite 

 ferment and incubated at 25°C. Tests made at various inter- 

 vals yielded the results given in table 6 where signifies a nega- 

 tive result and 1, +, 7^ positive results of increasing intensity. 

 On a short period of incubation, although free atmospheric 

 carbon dioxide was in contact with the solutions no appreciable 

 nitrification took place, when magnesium oxide was used, while 

 nitrification was active in the presence of the carbonate. 



Experiment 240 



The above cultures in which no appreciable nitrification took 

 place (nos, 4, 5, 6) were each divided into two equal portions by 

 means of sterile pipettes and placed, without reinoculation, in 

 sterile flasks of equal diameter. One portion, left as control, 

 received no addition whereas the other portions received various 

 treatments, as is shown in table 7. 



TABLE 7 



