240 Intelligence and Miscellaneous Articles. 



which he supposed to be acetic acid, but which has long since been 

 identified with lactic acid. 



The results of the author's experiments are at variance with the 

 general opinions upon the products of fermentation : — 



1. The acid of alcoholic fermentation is never either acetic or 

 lactic acid. 



2. Alcohol and carbonic acid are not the only products of the 

 splitting-up of sugar. They are always accompanied by succinic 

 acid and glycerine. The proportion of succinic acid varies between 

 5 and 7 thousandths, and that of glycerine between 25 and 36 thou- 

 sandths of the weight of sugar set in fermentation. 



3. The alcohol and carbonic acid do not equate with a definite 

 weight of sugar, that is to say, the alcohol and carbonic acid are 

 not in the proportions indicated by the theoretical equation ; more 

 carbonic acid is evolved than is required by the weight of alcohol 

 produced. 



4. More than 1 per cent. (1*2 to 1*5) of the weight of sugar is 

 fixed upon the yeast in the form of various matters, amongst which 

 are cellulose and fatty substances. 



Thus of lOOgrms. of sugar which are fermented, 5 to 6 grms. do 

 not follow the equation of Lavoisier and Gay-Lussac ; and this por- 

 tion of sugar is transformed by assimilating water in such a way as 

 to furnish in ordinary cases — 



grm. grra. 



Succinic acid 0*6 to 0"7 



Glycerine 3-2 „ 3*6 



Carbonic acid 0*6 „ 0"7 



Cellulose, fatty matters, and other products still 



undetermined 1'2 ,, 1'5 



Total .... 5-6 to 6-5 



The remainder of the sugar appears to correspond with the whole 

 of the alcohol and the rest of the carbonic acid, in accordance with 

 the equations of Lavoisier and Gay-Lussac. 



The question here arises whether the succinic acid and glycerine 

 with the carbonic acid which accompanie.* them, may not be the 

 results of a secondary and accidental action. This the author can- 

 not admit, as in more than a hundred analyses of fermentations 

 effected under the most different conditions, these products were 

 always obtained. 



In wine also he found that succinic acid and glycerine are present 

 in considerable quantity ; 1 litre of wine contains 6 to 8 grms. of 

 glycerine, and 1 to 1*5 grm. of succinic acid. The solid residue of 

 the evaporation of a litre of wine being from 15 to 25 grms., it will 

 be seen that more than a third, and often more than half of the solid 

 materials of wine have been unknown to the present day. — Comptes 

 Rendus, June 27, 1859, p. 1149. 



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