614 Adeney — Dissolved Gases and Fermentative Changes. 



obtain a nitric fermentation of ammonia under like conditions has, so far as I 

 know, failed. 



It was, however, perfectly well known that a nitric fermentation could be set 

 up in inorganic solutions of ammonia, seeded by fresh soil. The question 

 remained in obscurity until Warrington, in his last published " Researches on 

 Nitrification," already referred to, showed that he had, in the course of his work, 

 obtained some mixed organisms, some of which at least produced neither nitrous 

 nor nitric acid from ammonia, but which energetically converted nitrites into 

 nitrates. 



Warrington showed further, that the presence of ammonia retarded the action 

 of the nitric organisms on nitrites. 



Winogradsky has since isolated, from soil cultivations, the organisms which 

 has the power of fermenting nitrites to nitrates in inorganic solutions. 



On referring to the experiments, which I have recorded on the fermentation 

 of ammonia in the presence of peaty matters, and also, indeed, to such of those of 

 other observers as were carried out in the presence of fresh soil, which it must 

 be remembered no doubt contained organic bodies of a similar character and 

 influence, in the shape of humus, to the peaty matters of my experiments, one 

 cannot but be struck with the apparently direct influence of these matters on the 

 fermentation. Thus, in the experiments 2, 3, 4, and 5, recorded in Table XV., 

 the solution employed for which contained a large quantity of ammonia chloride 

 relatively to the peaty matters, but in which the peaty matters were present in 

 decided quantities, the nitric fermentation predominated, notwithstanding the 

 fact that a considerable quantit}^ of ammonia remained after the last experiment, 

 No. 5 ; while with the more dilute solution in which the ammonia, so far as the 

 fermentation was concerned, still remained large in quantity, but in which the peaty 

 matters might be considered small in theii- relation to that of the ammonia, we 

 get the reverse action shown, and the nitrous fermentation is seen to have 

 predominated. 



Again, if we refer to the experiments recorded in Table XVI., we find three 

 solutions, all seeded with similar organisms, but differing markedly in other 

 essential conditions : — 



No. 1 is a pm-ely inorganic solution, and in it a pm'ely nitrous fermentation 

 took place. 



No. 2 contained peaty matters, and in it not only was a nearly pure nitric 

 fermentation obtained, but the oxidized inorganic nitrogen product, in jjroiDortion 

 to the oxygen consumed, was decidedly larger than in the case of solution 1. 



Again, in solution No. 3, a nitric fermentation of nitrous acid is shown, in 

 which the oxidized nitrogen product is, as in the case of the solution No. 2, theo- 

 retically equivalent to a much larger volume of oxygen than that actually consumed. 



