484 



ATJGUSTO BONAZZI 



But the question of the growth of the nitrosoferment in an 

 environment only initially free of carbon dioxide is as yet an 

 open one. In order to answer the theoretical question advanced 

 by Duclaux, cultures in full nitrification are best adapted, 

 since in these the COo-production from equations I and II is con- 

 siderable. 



a, Soda lime; h, furnace at 900-1000°C. ; c, soda lime; d-e, concentrated KOH; 

 /, soda lime; g, stop-cock; h, culture chamber; i, Hg. manometer. 



Experiment 200 



An apparatus prepared as is shown in figure 1. 



The culture was in full nitrification when used and the experi- 

 ment was started by aerating the flask for two and one-half 

 hours, with air freed of CO2 by passing through the train shown 

 above. After aeration stopcock g was closed and the flask was 

 incubated on a clinostat (Bonazzi, 1919 b). The quantities of 

 nitrite formed before and after the treatment are given in table 3. 



TABLE 3 



Experiment 229 and 229a 



The apparatus used in these experiments were such that no 

 negative pressures could obtain in the culture systems; the 

 aeration train was similar to the one used in experiment 200, 



