STUDIES ON FERMENTATIOX. 269 



withdrew the plums and compared them with those which had 

 heen left exposed to the air. The difference was striking, 

 almost incredible. Whilst the plums which had been surrounded 

 wdth air (the experiments of Berard have long since taught us 

 that, under this latter condition, fruits absorb oxygen from the 

 air and emit carbonic acid gas in almost equal volume) had 

 become very soft and watery and sweet, the plums taken from 

 under the jar had remained very firm and hard, the flesh was 

 by no means watery, but they had lost much sugar. Lastly, 

 when submitted to distillation, after crushing, they yielded 6*5 

 grammes (99 "7 grains) of alcohol, more than 1 per cent, of 

 the total weight of the plums. What better proof could we 

 have than these facts of the existence of a considerable 

 chemical action in the interior of fruit, an action which derives 

 the heat necessary for its manifestation from the decomposition 

 of the sugar present in the cells ? Moreover, and this circum- 

 stance is especially worthy of our attention, in all these experi- 

 ments we found that there was a liberation of heat, of which 

 the fruits and other organs were the seat, as soon as they were 

 plunged in the carbonic acid gas. This lieat is so considerable 

 that it may at times be detected by the hand, if the two sides 

 of the cylinder, one of which is in contact with the objects, are 

 touched alternately. It also makes itself evident in the for- 

 mation of vapour, which condenses in little drops on those 

 parts of the bell which are less directly exposed to the influence 

 of the heat resulting from the decomposition of the sugar of 

 the cells.* 



* lu these studies on plauts living immersed in carbonic acid gas, we 

 have come across a fact which corroborates those which we have already 

 given in reference to the facility with which lactic and viscous ferments, 

 and, generally speaking, those which we have termed the disease-fer- 

 ments of beer, develop when deprived of air, and which shows, conse- 

 quently, how very marked their aerobian character is. If we immerse 

 beetroots or turnips in carbonic acid gas, we produce well-defined 

 fermentations in those roots. Their whole surface readily permits the 

 escape of the highly acid liquids, and they become filled with lactic, 

 viscous, and other ferments. This shows us the great danger which may 



