ON NITRIFICATION 



IV. THE CARBON AND NITROGEN RELATIONS OF THE NITRITE 



FERMENT 



AUGUSTO BONAZZI 



Contribution from the Laboratory of Soil Biology of the Ohio Agricultural Experi- 

 ment Station, Wooster, Ohio 



Received for publication, January 21, 1921 



Winogradsky (1890) showed that the organism of nitroso- 

 fermentation is capable of growing in a medium completely void 

 of fixed organic matter when in presence of ordinary air. He 

 proved, thereby, that the organism must derive its carbon from 

 one or all of the ■ following sources; the mineral carbonates, the 

 free carbon dioxide, or the volatile organic compounds of the 

 atmosphere. 



That a source of carbon is found and utilized by the organism 

 is supported by the fact that analysis of the culture liquid after 

 nitrosofermentation has taken place shows it to contain an 

 appreciably greater quantity of carbon than it did before the 

 fermentation was activated by inoculation. 



Godlewsky (1892, 1895) as well as Winogradsky and Omeli- 

 ansky (1899), found that cultures of nitrite and nitrate-forming 

 organisms lacking free or combined carbon dioxide could not 

 develop. In discussing the experiments of Winogradsky, above 

 referred to, Beijerinck (1903), points to the possibility that the 

 carbon was not fixed by the cells but by the magnesium oxide 

 present in the basic carbonate used by this investigator. If 

 this criticism were true it is hard to understand why the ratio 

 of ''nitrogen nitrified" to ''carbon assimilated" should b'e a 

 constant value. It might be assumed that the results of Ashby 

 (1907-8), (soon to be related) could support Beijerinck's hypothe- 

 sis, but close scrutiny shows them to bear a different significance. 



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JOURNAL OF BACTERIOLOGT, VOL. VI, KO. 5 



