the Ferment of Madder on Sugar, 178 



But it still remains uncertain, and the point is one of con- 

 siderable 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 myself 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. 



The conversion of sugar into alcohol and carbonic acid, and 

 also that of sugar into butyric acid, carbonic acid and hydrogen, 

 are well-understood processes. In the former case 1 equiv. of 

 sugar splits up into 2 equivs. of alcohol, and 4 equivs. of car- 

 bonic acid. 



1 equiv. sugar. Alcohol. 



C12 HIS 012= 2C4 H6 02 + 400^. 



In the second case, I equiv. of sugar splits up into 1 equiV. 

 of butyric acid, 4 equivs. of carbonic acid, and 4 equivs. of hy- 

 drogen*. 



1 equiv. sugar. Butyric acid. 



Ci2Hi2oi2 = C8H«04+4C0^-f4H. 



But as regards succinic acid, it is difficult to indicate with 

 positive certainty in what manner it takes its rise from sugar ; 

 because, in the fermentation of the latter with erythrozym, it is 

 evident that there are two processes going on side by side, the 

 one being the formation of alcohol, the other that of succinic 

 acid ; and it is doubtful whether all the carbonic acid evolved is 

 due to the one process alone or not, and also whether all the 

 acetic acid formed arises from the oxidation of the alcohol, or 

 whether a part of it does not proceed directly from the decom- 

 position of sugar. 



That the disengagement of hydrogen in this process stands in 

 some relation to the formation of succinic acid, will admit, I 

 think, of no doubt ; but I would not venture to assert that the 

 whole quantity of that gas evolved is due to the process of de- 

 composition by which this acid is formed. Of the possible 

 modes of decomposition by which succinic acid may be formed 

 from sugar, I will indicate a few. 1 equiv. of sugar may split 

 up into 3 equivs. of succinic acid and 3 equivs. of hydrogen ; or 

 with the elements of 8 equivs. of water into 1 equiv. of succinic 



products I have not been able to detect lactic acid, which constitutes the 

 intermediate stage between sugar and butyric acid. 



* I leave out of consideration the fact that sugar, before being decom- 

 posed in the manner mentioned, is first converted into lactic acid ; but this 

 fact is of no consequence as regards the result, since sugar and lactic acid 

 have the same per-centage composition. 



