STUDIES ON FERMENTATION. 267 



within the class of ferments, properly' so called. We can even 

 conceive that the fermentative character may belong to every 

 organized form, to every animal or vegetable cell, on the sole 

 condition that the chemico- vital acts of assimilation and excretion 

 must be capable of taking place in that cell for a brief period, 

 longer or shorter it may be, without the necessity for recourse to 

 supplies of atmospheric oxygen ; in other words, the cell must 

 be able to derive its needful heat from the decomposition of 

 some body which yields a surplus of heat in the process. 



As a consequence of these conclusions it should be an easy 

 matter to show, in the majority of living beings, the manifesta- 

 tion of the phenomena of fermentation ; for there are, probably, 

 none in Vvhich all chemical action entirely disappears, ujjon 

 the sudden cessation of life. One day, when we were expressing 

 these views in our laboratory, in the presence of M. Dumas, 

 who seemed inclined to admit their truth, we added : " We 

 would make a wager that if we were to plunge a bunch of grapes 

 into carbonic acid gas, there would be immediately produced 

 alcohol and carbonic acid, in consequence of a renewed action 

 starting in the interior cells of the grapes, in such a way that 

 these cells would assume the function of yeast-cells. We will 

 make the experiment, and when you come to-morrow — it was 

 our good fortune to have M. Dumas working in our laboratory 

 at that time — we will give you an account of the result." Our 

 predictions were realized. We then endeavoured to find, in 

 the presence of M. Dumas, who assisted us in our endeavour, 

 cells of yeast in the grapes ; but it was quite impossible to 

 discover any.* 



* To determine the absence of cells of ferment in fruits that have been 

 immersed in carbonic acid gas, we must first of all carefully raise the 

 l)ellicle of the fruit, taking care that the subjacent parenchyma does not 

 touch the surface of the pellicle, since the organized corpuscles existing 

 on the exterior of the fi'uit might introduce an error into our microscopi- 

 cal observations. Experiments on grapes ha^ve given us an explanation 

 of a fact generally known, the cause of which, however, had hitherto 

 escaped our knowledge. We all know that the taste and aroma of the 

 vintage, that is, of the grapes stripped from the bunches and thrown into 



