THEORY OF FERMENTATION 371 



It is through it alone that an albuminous substance and sugar 

 are enabled to unite and form this particular combination, 

 this unstable form under which alone, as a component part 

 of the mycoderm, they manifest an action on sugar. Should 

 the mycoderm cease to grow, the bond which unites the con- 

 stituent parts of the cellular contents is loosened, and it is 

 through the motion produced therein that the cells of yeast 

 bring about a disarrangement or separation of the elements 

 of the sugar into molecules." 



One might easily believe that the translator for the 

 Annales has made some mistake, so great is the obscurity of 

 this passage. 



Whether we take this new form of the theory or the old 

 one, neither can be reconciled at all with the development 

 of yeast and fermentation in a saccharine mineral medium, 

 for in the latter experiment fermentation is correlative to the 

 life of the ferment and to its nutrition, a constant change 

 going on between the ferment and its food-matters, since all 

 the carbon assimilated by the ferment is derived from sugar, 

 its nitrogen from ammonia and phosphorus from the phos- 

 phates in solution. And even all said, what purpose can be 

 served by the gratuitous hypothesis of contact-action or com- 

 municated motion? The experiment of which we are speak- 

 ing is thus a fundamental one; indeed, it is its possibility 

 that constitutes the most effective point in the controversy. 

 No doubt Liebig might say, "but it is the motion of life and 

 of nutrition which constitutes your experiment, and this is 

 the communicated motion that my theory requires." Curi- 

 ously enough, Liebig does endeavour, as a matter of fact, 

 to say this, but he does so timidly and incidentally: " From 

 a chemical point of view, which point of view I would not 

 willingly abandon, a vital action is a phenomenon of motion, 

 and, in this double sense of life M. Pasteur's theory agrees 

 with my own, and is not in contradiction with it (page 6)." 

 This is true. Elsewhere Liebig says: 



" It is possible that the only correlation between the physi- 

 ological act and the phenomenon of fermentation is the pro- 

 duction, in the living cell, of the substance which, by some 

 special property analogous to that by which emulsin exerts 

 a decomposing action on salicin and amygdalin, may bring 



