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From the peduncle, two small threadlike vessels proceed to the 

 seeds a (1 and 2), and, as the grape berry ripens, assume a rusty 

 violet colouration. 



Section of a Grape Berry. 



Around the pips (a) is the zone (6), which contains very little 

 sugar, and mostly viscous albuminous substances, free acids, and 

 cream of tartar. 



The layer c contains mostly water, sugar, and small quantities 

 of acids and albuminoid matters. 



Section d is richer in sugar and more fleshy, and contains 

 gummy substances, which, during the process of maturation, are 

 transformed into sugar ; a small amount of acids and albuminoid 

 substances are also met with there. 



Layer e, which underlines the pellicle, contains the colouring 

 matter, also tannic acid, and some aromatic substances which 

 impart a peculiar flavour to certain grapes, such as the Muscats, 

 Eiesling, Cabernet, Isabella, and other American grapes. These 

 natural aromas are quite distinct from those others which constitute 

 the bouquet of matured wines, and which are the result of chemical 

 reactions between the acids and the alcohol in the wine. The 

 colouring matter, or onocyanine, although generally lining the skin 

 of grapes, is occasionally found in the pulp of some varieties. 

 There are two distinct sorts a yellow and a blue one which, when 

 in contact with the acids in the wine, turn red. 



As grapes ripen, there is a gradual migration of the sugar from 

 the centre towards the circumference, where it accumulates under 

 the skin. This explains why, when pressing grapes which are dead 

 ripe, the juices which run out first are not so sweet as those which 

 flow when greater and more prolonged pressure has been applied. 



