FEKMENTATION. 43 



These theoretic ideas regarding the part played in 

 fermentation by the oxygen of the air were based upon 



riments made in the beginning of the century by 

 Gay-Lussac. In examining the process of Appert for 

 the preservation of animal and vegetable substances 

 a process which consisted in inclosing these sub- 

 stances in hermetically sealed vessels and heating 

 them afterwards to a sufficiently high temperature 

 Gay-Lussac had seen, for example, the must of the 

 grape, which had been preserved without alteration 

 during a whole year, caused to enter into a state of 

 fermentation by the simple fact of its transference to 

 another vessel that is to say, by having been brought 

 for an instant into contact with the oxygen of the air. 

 The oxygen of the air appeared, thfen, to be iheprimum 

 movens of fermentation. 



The illustrious chemists Berzelius and Mitscherlich 

 explained the phenomena of fermentation otherwise. 

 They placed these phenomena in the obscure class 

 known as phenomena of contact. The ferment, in their 

 view, took nothing from, and added nothing to, the 

 fermentable matter. It was an albuminoid substance, 

 endowed with a force to which the name catalytic was 

 given. The ferment in fact acted by its mere presence. 



A very curious observation, however, had been 

 made in France by Cagniard-Latour and in Germany 

 by Schwann. Cagniard-Latour, however, was the first 

 to publish this observation, which was destined to be- 



