268 STUDIES ON FERMENTATION-. 



Encouraged b}' this result^ we undertook fresh experiments 

 on grapes, on a melon, on oranges, on plums, and on rhubarb 

 leaves, gathered in the garden of the Ecole Kormale, and, in 

 every case, our substance when immersed in carbonic acid gas, 

 gave rise to the production of alcohol and carbonic acid. We 

 obtained the following surprising results from some prunes de 

 Monsieur* : — On July 31st, 1872, we placed twent3^-four of these 

 plums imder a glass cylinder, which we immediately filled with 

 carbonic acid gas. The plums had been gathered on the pre- 

 vious day. By the side of the cylinder we placed other twenty- 

 four plums, which were left there uncovered. Eight days 

 afterwards, in the course of which time there had been a con- 

 siderable evolution of carbonic acid from the cylinder, we 



tubs, where they get soaked in the juice that issues from wounded 

 specimens, are very different from the taste and aroma of an uninjured 

 bunch. Now grapes that have been immersed in an atmosphere of 

 carbonic acid gas have exactly the flavour and smell of the vintage ; the 

 reason is that, in the vintage tub, the grapes are immediately surrounded 

 by an atmosphere of carbonic acid gas, and undergo, in consequence, the 

 fermentation peculiar to grapes that have been plunged in this gas. 

 These facts deserve to be studied from a practical point of view. It 

 would be interesting, for example, to learn what difference there 

 would be in the quality of two wines, the grapes of which, in the one 

 case, had been perfectly crushed, so as to cause as great a separation of 

 the cells of the parenchyma as possible ; in the other case, left, for the 

 most part, whole, as in the case in the ordinary vintage. The first wine 

 would be deprived of those fixed and fragrant principles produced by the 

 fermentation of which we have just spoken, when the grapes are 

 immersed in carbonic acid gas. By such a comparison as that which we 

 suggest, we should be able to form an «/;rj'orf judgment on the merits of 

 the new system, which has not been carefully studied, although already 

 widely adopted, of milled, cylindrical crushers, for pressing the vintage. 



* We have sometimes found small quantities of alcohol in fruits and 

 other vegetable organs, surrounded with ordinary air, but always in 

 small proportion, and in a manner which suggested its accidental charac- 

 ter. It is easy to understand how, in the thickness of certain fruits, 

 certain parts of those fruits might be deprived of air, under which 

 circumstance they would have been acting under conditions similar to 

 those under which fruits act when wholly immersed in carbonic acid gas. 

 Moreover it would be useful to determine whether alcohol is not a normal 

 product of vegetation. 



