BUTYRIC ACID FERMENTATION 347 



has rejected, it is true, the view that dioxyacetone is an 

 intermediate product of alcoholic fermentation, from the 

 fact that while, for example, a decigram of dextrose in an 

 experiment was completely fermented by yeast in twenty 

 minutes, a decigram of dioxyacetone in parallel experiment 

 underwent practically no change. 50 The justice of such 

 criticism is, however, not accepted by the first-named in- 

 vestigators. 51 



Recent studies of Lebedew, Harden and Young, and of 

 Euler seem to indicate that the phosphoric acid contained in 

 the fermentation mixtures plays an important role in the 

 fermentation, uniting with hexose to form an ester which 

 much more readily lends itself to fermentation cleavage; 

 perhaps, too, the possibility of an intermediate formation 

 of a triose or triose-ester in the course of the fermentation 

 ought to be thought of. 52 At best the whole matter is at 

 present vague and uncertain. 



Butyric Acid Fermentation. In the au thor's opinion 

 there may be some interest in the observations which have 

 been made upon the mechanism of butyric acid fermentation 

 in their bearing upon the study of the processes of physio- 

 logical catabolism of sugar. Butyric acid may be formed 

 from hexoses as well as from lactic acid from fermentation. 

 Buchner and Meisenheimer 53 conceive of the process in this 

 fashion : that the sugar first is split into lactic acid, and this 

 in turn into acetaldehyde 54 and formic acid, two molecules 



50 A. Slator, Ber. d. deutsch. chem. Ges., 45, 43, 1912. 



61 E. Buchner and Meisenheimer, Ber. d. deutsch. chem. Ges., 4$, 1632, 

 1912; cf. also Harden and Young, ibid., 40, 458, 1912; Chick (Lister Instit., 

 London), Biochem. Zeitschr., 40, 479, 1912. 



62 A. v. Lebedew (Instit. Pasteur), Ber. d. deutsch. chem. Ges., 44, 2932, 

 1911; Biochem. Zeitschr., 36, 248, 1911; Ann. Instit. Pasteur, 25, 847, 1911; 

 H. Euler (Stockholm), with Kullberg, Ohls6n, Fodor, Zeitschr. f. physiol. 

 Chem., 74, 15, 1911; 76, 468, 1911; Biochem. Zeitschr., 36, 401, 1911. 



53 E. Buchner and J. Meisenheimer, Ber. d. deutsch. chem. Ges., 41, 1910, 

 1908. 



64 Cf . statements of Kostytschew ( St. Petersburg ) , Zeitschr. f . physiol. 

 Chem., 79, 130, 1912, upon the formation of acetaldehyde in alcoholic fermenta- 

 tion of sugar. 



