332 On ike Cultivation of the k^ine, 



and the weather which prevails during the vintage — all these 

 causes and their effects must he alw ys present in the mind 

 of the agriculturist, that he may he able to deduce from them 

 rules proper for directing his conduct in regard to this object. 



4. Liflueiice of the constituent Principles of Must on 

 Fermentation, 



The sweet and saccharine principle, water, and tartar, are 

 the three elements of the grape which seem to have a power- 

 ful influence on ferujentation : it is not only to their exist- 

 ence that the first cause of this sublime operation is due, but 

 it is to the very variable proportions of these different con- 

 stituent principles that we must refer the principal differences 

 exhibited by fermentation. 



Ist^ It appears proved, by comparing the nature of all the 

 substances which undergo spiritous fermentation, that none 

 are susceptible of it but those which contain a sweet and sac- 

 charine principle; and it is beyond a doubt that it is at the 

 expense of this principle that alcohol is formed. By a con- 

 sequence which naturally flows from this fundamental truth, 

 bodies in which the saccharine principle is most abundant 

 ought to furnish the most spiritous liquor. This is what is 

 confirmed by experience. But it is impossible to insist too 

 much on the necessity of making a careful distinction between 

 sugar properly so called and the sweet pri?iciple. Sugar 

 without doubt exists in grapes, and it is to it in particular 

 that is owing the alcohol which results from its deconi|jositioii 

 by fermentation ; but this sugar is constantly mixed with a 

 sweet body, more or less abundant, and very proper for fer- 

 mentation : it is a real leaven, which almost every where ac- 

 companies sugar, but which by itself cannnot produce alcohol. 

 Hence it happens that, when it is necessary to ferment sugar 

 in order to obtain rum, it is employed in the state of syrup 

 called vezou, because it then contains the sweet principle which 

 facilitates the fermentation. 



The distinction between the sweet principle and sugar pro- 

 perly so called has been very well established by Deyeux in the 

 Journal des Pkarmaciens, 



This sweet principle is almost inseparable from the prin- 

 ciple 



