Vegetable Sttbstances. 285 



fermentation, the vinous, the acetous, and the 

 putrefactive, though in reality they are three 

 different processes. 



The phasnomena attending the vinous fer- 

 mentation are 1 st, An intestine motion or agi- 

 tation in the fluid; 2dly, The fluid becomes 

 thick and muddy; Sdly, The temperature in- 

 creases; 4thly, Carbonic acid gas is evolved, 

 and hangs over the fermenting liquor; 5thly, 

 The fermentation ceases, the thick part rises to 

 the top, or sinks to the bottom, and the liquor 

 is entirely changed. It has lost its saccharine 

 taste; its specific . gravity is diminished. It is 

 found to contain a quantity of alcohol, which 

 may be separated from it by distillation. 



To explain this phasnomena, it must be re- 

 membered that alcohol, which is the essential 

 part of every vinous fluid, consists of the same 

 ingredients as sugar, only combined in different 

 proportions. Alcohol contains more hydrogen, 

 and less carbon and oxygen. In the process of 

 fermentation, therefore, a considerable part of 

 the oxygen and carbon contained in the ferment- 

 ing fluid combine, and go off in the form of 

 carbonic acid gas ; and the quantities of these 

 being lessened, while the whole of the hydrogen 

 is left behind, the nature of the fluid is necessarily 

 changed. 



In the acetous fermentation the process is still 

 more simple than in the vinous. It is well 

 known that when any vinous fluid is exposed to 



