Dr. Schixnck on the Phmiomena of Fermentation. 341 



ments which I had made on the action of the ferment of madder 

 on sugar. These experiments were undertaken in order to ascer- 

 tain whether this ferment, which I call erythrozym, and which in 

 several respects differs very widely from other ferments, would 

 have the same effect on sugar as ordinary ferments, such as yeast. 

 Now I discovered among the products of this process of fermen- 

 tation, besides alcohol and carbonic acid, a small quantity of an 

 acid having the properties and composition of succinic acid ; and 

 as the formation of this acid from sugar had until then not been 

 obsex-ved, I was led to believe that it was characteristic of the 

 particular process of fermentation induced by erythrozym. To 

 M. Pasteur belongs the merit of having discovered that succinic 

 acid uniformly makes its appearance along with alcohol and car- 

 bonic acid in ordinaiy fermentation. That this discovery was, 

 however, not entirely unanticipated, will be evident from the fol- 

 lowing quotation taken from the paper just mentioned : — " But 

 it still remains uncertain, and the point is one of considerable 

 interest, whether the formation of succinic acid from sugar is a 

 specific effect due to erythrozym alone, or is shared by the latter 

 in common with other ferments, such as yeast and emulsine. 

 On this point I have no evidence to offer, but must content my- 

 self with a few general considerations, leading to the conclusion 

 that it is not improbable that other ferments will be found 

 capable, under peculiar circumstances, of producing this acid 

 from sugar." 



As succinic acid is formed from a variety of substances by 

 different processes of decomposition, I took the precaution of 

 ascertaining whether in this case it might not be derived from 

 the elements of the ferment itself, and I found that not a trace 

 was obtained when the ferment was allowed to decompose with- 

 out the addition of sugar. I may also mention that, when sugar 

 is made to ferment by means of erythrozym, the gas which is 

 evolved contains a notable quantity of hydrogen. Whether the 

 disengagement of hydrogen in this case stands in any relation to 

 the formation of succinic acid or not, I could not with certainty 

 ascertain. Probably it does not, since M. Pasteur makes no 

 mention of the evolution of hydrogen in his experiments. 



Further details may be found on reference to the paper itself. 

 I am. Gentlemen, 



Yom- most obedient Servant, 



Belfield Hall, Rochdale, E. ScHUNCK. 



October 4, 1859. 



