608 Adeney — Dissolved Gases and Fermentative Changes. 



It is possible also, since the ammoniacal nitrogen absorbed during the experi- 

 ment was slightly in excess of the total nitrogen oxidized, that none of the latter 

 was derived from the peat. 



With reference to the question of the source of oxygen, the hydrogen of the 

 ammonia may not have been so completely oxidized to water during the fermen- 

 tation, in the presence of peaty matters, as in the absence of all organic matter. 

 Some at least of the ammonical hydrogen may have been taken up by the peaty 

 matters, and an increased quantity of oxidized nitrogen woidd, no doubt, be the 

 results. 



But whatever the mechanics of the chemical changes may be, which go on 

 during fermentation, when peaty matters and ammonia are 2>resent together, the 

 influence of those matters, one upon the other, cannot be doubted. 



I have not hitherto referred to the loss of carbon dioxide shown by the 

 experiments 1 and 1 a with the inorganic solution, because, in each case, it is so 

 small as to be scarcely distinguishable from experimental errors. The determina- 

 tions recorded are important, however, in showing that the carbon fixed must be 

 very small compared with the nitrogen oxidized, and therefore they add additional 

 evidence to that already given by Winogradsky, who showed, by a process of wet 

 combustion, that the assimilation of 1 part of carbon was accompanied by the 

 oxidation of about 35 parts of nitrogen as ammonia to nitrous acid. The mean 

 of the losses of carbon dioxide shown by experiment 1 a is 0"15 c.cs., which is 

 equivalent to 0*00008 grammes carbon, the ratio of the mean of the two 

 quantities of nitrous nitrogen, recorded for the same experiment, viz. 0'0024:4 

 grammes, is as 1 : 30*5. These figures, it need hardly be said, are simply put 

 forward here as confirmation of those given by Winogradsky. 



In some of the preceding experiments, as I have before said, it appears that 

 very definite volumes of carbon dioxide have been fixed, presumably during the 

 formation of organic matters, but in all these experiments either peaty matters 

 or fermented animal organic bodies, or, in the case of these latter, it should 

 perhaps be said, both, as tap-water was employed for them, were present during 

 fermentation. 



Thus, the experiment with diluted sewage-water, S2 recorded on page 588, 

 shows a loss of as much as 0"77 c.cs., with a consmnption of 7*6 c.cs. of oxygen, 

 and the formation of only 0'00122 nitric nitrogen, and this experiment was 

 carried out with extreme care, and it may be taken that the errors affecting the 

 determinations are not seriously appreciable, since the quantities determined were 

 small. 



It appears then that peaty matters {and also fermented animal matters) influence the 

 quantity of carbon dioxide which may be fixed during a fermentation of ammonia. 



