THEORY OF FERMENTATION 293 



it weighed 2.25 grammes (34 grains). It is evident that in 

 this experiment the total amount of yeast formed, if it re- 

 quired oxygen to enable it to live > could not have absorbed, 

 at most, more than the volume which was originally held 



Fie. i 



in solution in the saccharine liquid, when that was exposed 

 to the air before being introduced into the flask. 



Some exact experiments conducted by M. Raulin in our 

 laboratory have established the fact that saccharine worts, 

 like water, soon become saturated when shaken briskly with 

 an excess of air, and also that they always take into solution 

 a little less air than saturated pure water contains under the 

 same conditions of temperature and pressure. At a tempera- 

 ture of 25 C. (77 F.), therefore, if we adopt the coefficient 

 of the solubility of oxygen in water given in Bunsen's tables, 

 we find that I litre (i# pints) of water saturated with air 

 contains 5.5 cc. (0.3 cubic inch) of oxygen. The three litres 

 of yeast-water in the flask, supposing it to have been satu- 

 rated, contains less than 16.5 cc. (i cubic inch) of oxygen, 

 or, in weight, less than 23 milligrammes (0.35 grains). This 



