28 THE GRAPE. 



malic acid in the juice of unripe grapes, and since 

 then it has been several times subjected to examina- 

 tion. Proust considered the acid of the unripe grapes 

 to be citric, and Kaufmann* has stated that unripe 

 grapes are peculiarly adapted to the preparation of 

 citric acid. 



Greigerf examined this subject more closely, and 

 found in unripe grapes both tartaric and malic, but 

 no citric acid. 



This is all that we have found asserted with any 

 probability respecting the existence of tartaric, and the 

 existence or non-existence of citric acid. So far as we 

 know, however, the three acids are rarely found together 

 in one fruit, but either citric or malic, or tartaric and 

 citric, or tartaric and malic acid. It would, therefore, 

 be an exception to the rule, if all three were found 

 in the grape juice in sufficient quantities to allow of 

 their being accurately distinguished. 



As, now, the existence of citric acid is not suffi- 

 ciently proved, and on the contrary, the presence of 

 malic acid in unripe, and of tartaric acid in ripe 

 grapes is established, we may certainly assume that 

 besides tartaric acid a fixed quantity of malic acid 

 may be found in wine, which will be small in pro- 

 portion to the ripeness of the grapes. No malic acid 

 appears to exist in wine which has been prepared 

 from perfectly ripe grapes. In some Bordeaux which 



* Kepert. der Pharm. Bd. 14, s. 77. 

 + Mag. fur Pharm. Bd. 7, s. 160. 



