Fermentations by Organisms 815 



Experiment CCCCXII. February 1. Instead of bells, of unequal 

 volumes, we use flasks of small dimensions, as is represented in Figure 

 74. 



In flask A is ordinary air; in B, air with 37.3% of oxygen; in C, 

 air with 61.2%; in D, air with 81%. 



February 7. Experiment ended; the analysis of the potash solu- 

 tions shows that: 



A has produced 317 cc. of carbonic acid. 



B has produced 326 cc. of carbonic acid. 



C has produced 393 cc. of carbonic acid. 



D has produced 328 cc. of carbonic acid. 



Experiment CCCCXIII. February 14. Temperature 16°. Same 

 apparatuses. 



In flask A, ordinary air. 

 In flask B, air with 41.5% of oxygen. 

 February 17. Ended the experiment. 

 A produced 130 cc. of carbonic acid. 

 B produced 178 cc. of carbonic acid. 



If we call the quantity of carbonic acid produced under normal 

 pressure 100 in each of these experiments, we shall obtain by 

 simple proportions the following figures, which show the course 

 of the production of carbonic acid. 



Ordinary air (1 atmosphere) there are 100 cc. of C0 2 



CCCCXII Air with 37.3% of O, (1.8 atmospheres) there are 103 cc of CO, 

 CCCCXIII Air with 41.5% of O, (2 atmospheres) there are 129 cc. of C0 2 

 CCCCX Air with 49.6% of O a (2.3 atmospheres) there are 106 cc. of CO, 

 CCCCXI. Air with 53% of 2 (2.5 atmospheres) there are 121 cc. of CO. 

 CCCCXII Air with 61.2% of O, (2.9 atmospheres) there are 124 cc. of CO, 

 CCCCXI Air with 79.7% of 2 (3.8 atmospheres) there are 112 cc. of CO, 

 CCCCXII. Air with 81% of O, (3.9 atmospheres) there are 103 cc. of CO, 



It appears from these figures that the maximum of combustion 

 in tissues takes place above normal pressure, at about three atmos- 

 pheres. This was the conclusion which we had already reached 

 in Subchapter II of Chapter IV, for combustions investigated in 

 living beings. 



When pressures become very high, the decrease of oxidations 

 in the tissues becomes extremely clear. At 23 atmospheres, the 

 proportion of oxygen consumed has lessened in the ratio of 534 to 

 32 (Experiment CCCLXXXVII). In Experiment CCCXCVI, con- 

 sumption at normal pressure in 5 days was 522 cc. of oxygen, 

 whereas it was only 49 cc. in compressed air at a tension equivalent 

 to 42.5 atmospheres of air, and in the 9 following summer days, 

 although the tension had been lowered to 11 atmospheres, only 

 210 cc. of oxygen were consumed. 



