Fermentations by Organisms 



813 



as the measure of the intensity of the phenomena of putrefaction 

 the consumption of this gas in a given time. 



We shall state here that we are relying both on experiments 

 made in compressed air, and on those in which high oxygen ten- 

 sion was obtained by increasing not the pressure, but the percentage 

 under ordinary barometric pressure. We are sufficiently justified 

 in this identification by all that we have hitherto observed. 



Experiment CCCXCII shows us that the quantity of oxygen 

 consumed increases with a tension corresponding to 2 and even 

 to 3 atmospheres of air; Experiments CCCXCIX and CCCCI give 

 the same result for 3 atmospheres; but Experiment CCCXCI shows, 

 in its first part, that there is a decrease at the tension of 4V2 at- 



Fig. 74 — Oxygen consumption and carbonic acid production by a piece of 

 meat in an atmosphere of constant oxygen content. 



mospheres; finally, Experiment CCCCII shows equality of con- 

 sumption at 4 atmospheres. 



It seems then, at first, that the maximum consumption of oxygen 

 occurs between 3 and 4 atmospheres. But the question is more 

 difficult to settle than one would think at first, and requires experi- 

 ments carried on with special precautions. In fact, in Experiment 

 CCCXCII, for example, the air of bell D, in which the oxygen ten- 

 sion corresponded at first to 3 atmospheres of air, and in which 

 there was more active oxidation, corresponded to less than 2 at- 

 mospheres at the end of the experiment. One must use here an 



