284 VINOUS FERMENTATION. 



its decomposition is completed, the quantity of fer- 

 ment or yeast is found to be thirty times greater 

 than it was originally. 



Yeast from beer and that from wine, examined 

 under the microscope, present the same form and 

 general appearance. They are both acted on in 

 the same manner by alkalies and acids, and possess 

 the power of inducing fermentation anew in a 

 solution of sugar ; in short, they must be considered 

 as identical. 



The fact that water is decomposed during the 

 putrefaction of gluten has been completely proved. 

 The tendency of the carbon of the gluten to appro- 

 priate the oxygen of water must also always be in 

 action, whether the gluten is decomposed in a 

 soluble or insoluble state. These considerations, 

 therefore, as well as the circumstance which all the 

 experiments made on this subject appear to point out, 

 that the conversion of gluten to the insoluble state 

 is the result of oxidation, lead us to conclude that 

 the oxygen consumed in this process is derived 

 from the elements of water, or from the sugar which 

 contains oxygen and hydrogen in the same propor- 

 tion as water. At all events, the oxygen thus con- 

 sumed in the fermentation of wine and beer is not 

 taken from the atmosphere. 



The fermentation of pure sugar in contact with 

 yeast must evidently be a very different process 

 from the fermentation of wort or must *. 



* The liquid expressed from grapes when fully ripe is called must. 



