492 



AUGUSTO BONAZZI 



TABLE 8 



NUM- 

 BER 



TREATMENT 



(NH4)2S04 and MgCOs open... 

 (NH4)2S04 and MgCOs capped. 



(NH4)2C03 open 



(NH4)2C03 capped 



(NH4)2C03 and MgCOs capped 

 (NH4)2C03 and MgO capped. . . 

 (NH4)2C03 and MgO capped... 



In no. 2 nitrification was, for some unknown reason, retarded, 

 for, even after nineteen days no nitrite formation had taken place, 

 so that the quantity found after thirty-one days was formed 

 during the last twelve days of incubation. The action of the 

 magnesium oxide on the nitrification of ammonium carbonate 

 is a retarding one and this may be due to physical reasons. 

 Distillation of the ammonia from the neutral or slightly acid 

 solution takes place at a relatively fast rate, as is shown in no. 

 3 and in a solution made alkaline by the addition of MgO the 

 distillation is too fast to allow any competition by the bacterial 

 cells. 



Since it is evident from these experiments that the ammonium 

 carbonate can be utilized by the nitrosoferment even in the 

 absence of a base, a study of the nitrification of this substance 

 in the presence or absence of atmospheric carbon dioxide will 

 lead to a better understanding of the function of the magnesium 

 carbonate in the cultures undergoing nitrification. Besides, 

 if ammonium carbonate were nitrified in the absence of atmos- 

 pheric carbon dioxide it would be evident that this nitrogenous 

 carbonated substance could furnish the carbon necessary for 

 the life of the organism. The latter condition would also 

 indicate the mode of action of the compound. 



