486 CHEMISTRY OF ALCOHOLIC FERMENTATION. 



the opinion that the changes suffered by organic substances 

 through the action of ferments fermentation are nearly always 

 effected with the active collaboration of water. Similarly, HOPPE- 

 SEYLER (VII.) wrote : " All fermentative processes go on in an 

 undisturbed manner only when the solutions are in a sufficiently 

 diluted state ; and the chemical collaboration of water seems to 

 be essential in all cases." Hence, the equation of alcoholic 

 fermentation should be expressed as : 



C 6 H 12 6 + 2H 2 = 2H 2 C0 3 + 2C 2 H 6 0, 



carbonic acid being formed in addition to alcohol. 



A slight divergence may be permitted here. The substance 

 generally called " carbonic acid " is really carbon dioxide or 

 carbonic anhydride, C0 2 , the acid properly so-called having the 

 formula H 2 C0 3 . This latter readily decomposes into carbon 

 dioxide and water, in accordance with the equation H 2 C0 3 = 

 H 2 + C 2 O, so that it is merely a temporary intermediate product. 

 According to A. BAEYER (I.) alcoholic fermentation proceeds in 

 two stages. In the first of these, the hydroxyl groups of the 

 sugar undergo displacement, accompanied by reduction of the one 

 series of carbohydrate groups and an accumulation of oxygen in 

 the other, the carbon chain then being subjected to fission where 

 the oxygen has accumulated. This results in the formation of either 

 the extreme anhydride of ethyl-carbonic acid or that of lactic 

 acid corresponding to alcoholic fermentation on the one hand 

 and lactic fermentation on the other. Other workers, e.g., 

 WAGNER (II.), 'RAYMAN and KRUIS (I.), also look upon the 

 alternate hydration and dehydration of the carbon atom as 

 probable, without, however, going more fully into the elucidation 

 of the fermentation process. 



FORMULA I. 

 a b 



CHO CHO 



CHOH I CHOH 



CHOH H | CH 2 OH 

 I + ! = +CH(OH) 2 CHO 



H I I 



CHOH CHOH -+ CHOH + H O 



I ! I 



CHOH CH 2 OH CH 2 OH 



CH 2 OH c d 



FORMULA II. FORMULA III. 



CHO CHO CHO COOH 



I i ! I I I 



CHOH + H! CHOH + H 2 Oo CHOH + = CHOH 



I 



'0 



L I I 



CH 2 [OHH I CH 3 CH 



