FIELD, FOREST AND FARM 



agreeably sweet taste, the same taste that makes 

 grapes so desirable a fruit for the table. This pleas- 

 ant flavor is due to a sort of sugar present in the 

 grapes. Examine carefully a handful of raisins such 

 as you buy at the grocer's: you will detect on their 

 surface, certain tiny white grains that crunch under 

 the teeth and have a sweet savor. Those grains 

 are little particles of sugar that have collected on the 

 outside of the grapes during the process of drying. 

 Grapes, then, must contain sugar. 



"Well now, this sugar is exactly what causes the 

 formation of alcohol. What is sugar in the fresh 

 juice of grapes is alcohol in the same juice after it 

 has fermented and turned to wine. Let us consider 

 briefly how this change comes about. 



' ' The vintage is first of all subjected to a process 

 of treading by men who trample on the grapes in 

 large vats, after which the resulting mixture of juice 

 and skins is left to 'work,' as we say. Before long 

 this liquid mush begins to heat of its own accord, 

 and presently there sets in a sort of boiling which 

 liberates big bubbles of gas as if there were a fire 

 underneath. This working process is called fer- 

 mentation, and its seat is in the sugar of the grape- 

 juice. Little by little the sugar decomposes, splits 

 apart as we might say, into two substances very 

 different from each other and also very different 

 from the sugar whence they came. Of these two 

 substances one is alcohol ; the other is a gas already 

 known to us — carbonic acid, the same gas that plants 

 feed on and that animals give forth in breathing; 



