Adeney — Dissolved Gases and Fermentative Changes. 581 



influence on the course, more especially of the earlier steps of the first stage 

 fermentation. 



Thus, from the first experiment with solution A diluted to 1 in 10, it is probable 

 from the quantities of carbon dioxide and ammonia formed, that the first stage 

 had run through but little more than half its course, but notwithstanding this, the 

 ratio of cai-bon dioxide formed to oxygen absorbed is as 1*4 ; 1. 



The influence of dilution is still more markedly shown by the results recorded 

 from experiment 3a with solution A diluted to 1 in 20. This experiment had been 

 allowed a decidedly longer time for fermentation ; and it seems probable from the 

 quantity of ammonia formed, that the first stage had nearly run its complete 

 course. 



The ratio between the above two gases, respectively, formed and absorbed 

 becomes as 1*15 : 1. 



It seems then from these two experiments that in the fermentative changes 

 that were set up in the earlier steps of the first-stage fermentation of these dilute 

 solutions, the dissolved oxj-gen took part to a degree increasing with the dilution, 

 and that the resulting compounds were in all probability more highly oxidized 

 than those formed during similar stages of fermentation in the undiluted solu- 

 tion A. 



On examining the results of the further experiment (4«) with the more 

 dilute solution, recorded in Table VIII., we find evidence to show that the 

 organic matters which are formed during the first stage in so dilute a solu- 

 tion, may themselves undergo further change during nitrification, and give 

 rise to the formation of carbon dioxide coincidentally with the oxidation of 

 ammonia. 



But it is of importance to note that from the quantity of nitrous and nitric acids 

 formed, and of oxygen absorbed, in experiment 4a, the formation of this carbon 

 dioxide could not have been attended with the absorption of any but a relatively 

 extremely small volume of oxygen. 



On turning to the results obtained from the second experiment {2a), with the 

 less dilute solution, we find evidence of a similar nature recorded. 



It may be urged, and rightly so, that from the way in wbicb the second 

 experiment (4a) with the more dilute solution of A was carried out, the volume 

 of oxygen absorbed during fermentation, recorded in Table VIII., is probably 

 too low. 



Unfortunately tbe quantity of liquid left from the experiment 3a was not 

 sufiicient to allow of re-aeration and analysis in the usual way before re-bottling ; 

 hence the necessity of carrying out experiment 4a in the manner described in the 

 Table. During the operation of transferring the liquid to a smaller bottle, it, no 

 doubt, absorbed a small quantity of oxygen from the air. This would not, of 



4N2 



