276 STUDIES ON FERMENTATION. 



of fruits is an ordinary alcoholic fermentation, identical with 

 that produced by beer-yeast, and that, consequently, the cells 

 of that yeast must, according to our own theory, be always 

 present. There is not the least authority for such a supposition. 

 When we come to exact quantitative estimations — and these 

 are to be found in the figures supplied by Messrs. Lechartier 

 and Bellamy — it will be seen that the proportions of alcohol 

 and carbonic acid gas produced in the fermentation of fruits 

 differ widely from those that we find in alcoholic fermentations, 

 properly so called, aa must necessarily be the case, since, in the 

 former, the ferment-action is effected by the cells of a fruit, but 

 in the latter by cells of ordinary alcoholic ferment. Indeed we 

 have a strong conviction that each fruit would be found to give 

 rise to a special action, the chemical equation of which would 

 be different from that in the case of other fruits. As for the 

 cii^cumstance that the cells of these fruits cause fermentation, 

 without multiplying, this comes under the kind of activity, 

 which we have already distinguished by the expression con- 

 tinuous life in cells already formed. 



We will conclude this paragraph with a few remarks on the 

 subject of the equations of fermentations, which have been 

 suggested to ns principally in attempts to explain the results 

 derived from the fermentation of fruits immersed in carbonic 

 acid gas. 



Originally, when fermentations were put amongst the class 

 of decompositions by contact-action, it seemed probable, and, in 

 fact, was believed, that every fermentation had its own well- 

 defined equation, which never varied. In the present day, on 

 the contrary, it must be borne in mind that the equation of a 

 fermentation varies essentially with the conditions under which 

 that fermentation is accomplished, and that a statement of this 

 equation is a problem no less complicated than that in the case 

 of the nutrition of a living being. To every fermentation may 

 be assigned an equation in a general sort of wa^-, an equation, 

 however, which, in numerous points of detail, is liable to the 

 thousand variations connected with the phenomena of life. 



