354f 



ON .TtlE SUGAR OP GRAPE?. 



The fee Ilia al- 

 tered by fer- 

 meatation. 



Fecula of the 

 2d stage. 



Does it contain 

 a principle of 

 feritientation. 



The gluten not 

 affected by fer- 

 mentation. 



-wliich retains the whole of its fecula. Hence let ns con- 

 clude, that the fecula is one of those products, which are 

 not necessary to fermentation, and that one of tlie first 

 etTocts of tills change is to free the juices from it, as it 

 frees them from the tartar and sulphate: that, if fermen- 

 tation required some of the other products of vegetation, to 

 enable it to produce its due cifecl, it is much more natural 

 to suppose, that those which their solubility renders injuri- 

 ous to the sugar would take a part, than an insoluble sub- 

 stance, which we always find again subsequent as well as 

 previous to it, and of which not the least traces are to be 

 found in wine or its products. 



The fresh fecula of the grape mixed with a solution of 

 sugar at 17" is incapable of fermentation, as Berthollet and 

 Thenai'd have already observed. I have also ascertained 

 this fact. But if with such a solution of sugar we mix the 

 same fecula after wine has fermented on it, or after it has 

 become lees, it will excite a very brisk fermentation in it in 

 a few hours. 



The while and muddy fecula deposited in the second stage 

 of fermentation does not dissolve in the fermenting liquors ; 

 it undergoes no decomposition in them; it changes neither 

 its bulk nor appearance; and there is no trace of it disco- 

 verable in the wine. It appears to take no part in the phe- 

 nomena of fermentation, yd it impresses on crystallizable 

 sugar the fermentative motion. In this case we see clearlj, 

 that it acts as matter impregnated with a principle which it 

 transmits. What then is this principle? All that remains 

 for us is to examine, whether we can divest fecula or lees of 

 this impregnation, this leaven, which fits them for exciting 

 fermentation ; to enable us afterward to determine, whether 

 the lees themselves really possess this property, or Avhether 

 they act only by virtue of this principle, in which case they 

 are merely a vehicle. This is a point on which Seguin ap- 

 pears to be occupied. 



In several spirituous fermentations, in which I have em- 



ployed yeast, or meal, the gluten has always risen to the 



top, and adhered in shreds to the mouths of the vessels; 



and I could easily perceive, that it had neither altered its 



nature, nor been alFcctcd by the changes of the fermenting 



medium. 



I have 



