THEORY OF FERMENTATION 363 



a long essay, reproduced from a lecture delivered by him 

 before the Academy of Bavaria in 1868 and 1869. In this 

 Liebig again maintained, not, however, without certain 

 modifications, the views which he had expressed in his 

 former publications, and disputed the correctness of the 

 principal facts enunciated in our Memoir of 1860, on 

 which were based the arguments against his theory. 



" I had admitted/' he says, " that the resolution of fer- 

 mentable matter into compounds of a simpler kind must be 

 traced to some process of decomposition taking place in 

 the ferment, and that the action of this same ferment on 

 the fermentable matter must continue or cease according to 

 the prolongation or cessation of the alteration produced in the 

 ferment. The molecular change in the sugar, would, con- 

 sequently, be brought about by the destruction or modifica- 

 tion of one or more of the component parts of the ferment, 

 and could only take place through the contact of the two 

 substances. M. Pasteur regards fermentation in the fol- 

 lowing light: The chemical action of fermentation is es- 

 sentially a phenomenon correlative with a vital action, 

 beginning and ending with it. He believes that alcoholic 

 fermentation can never occur without the simultaneous oc- 

 currence of organization, development, and multiplication of 

 globules, or continuous life, carried on from globules al- 

 ready formed. But the idea that the decomposition of 

 sugar during fermentation is due to the development of 

 the cellules of the ferment, is in contradiction with the 

 fact that the ferment is able to bring about the fermenta- 

 tion of a pure solution of sugar. The greater part of the 

 ferment is composed of a substance that is rich in nitrogen 

 and contains sulphur. It contains, moreover, an appreciable 

 quantity of phosphates, hence it is difficult to conceive how, 

 in the absence of these elements in a pure solution of sugar 

 undergoing fermentation, the number of cells is capable of 

 any increase." 



Notwithstanding Liebig's belief to the contrary, the idea 

 that the decomposition of sugar during fermentation is in- 

 timately connected with a development of the cellules of 

 the ferment, or a prolongation of the life of cellules already 

 formed, is in no way opposed to the fact that the fennenj 



