368 LOUIS PASTEUR 



remarkable facts, which are, however, at present but vaguely 

 connected with the alcoholic fermentation of sugar by 

 means of yeast. The researches in which we have proved 

 the existence of special forms of living ferments in many 

 fermentations, which one might have supposed to have been 

 produced by simple contact action, had established beyond 

 doubt the existence of profound differences between those 

 fermentations, which we have distinguished as fermentations 

 proper, and the phenomena connected with soluble sub- 

 stances. The more we advance, the more clearly we are 

 able to detect these differences. M. Dumas has insisted on 

 the fact that the ferments of fermentation proper multiply 

 and reproduce themselves in the process whilst the others 

 are destroyed. 4 Still more recently M. Miintz has shown 

 that chloroform prevents fermentations proper, but does not 

 interfere with the action of diastase (Comptcs rendus, 1875) 

 M. Bouchardat had already established the fact that hydro- 

 cyanic acid, salts of mercury, ether, alcohol, creosote, and 

 the oils of turpentine, lemon, cloves, and mustard destroy or 

 check alcoholic fermentations, whilst in no way interfering 

 with the glucoside fermentations (Annalcs dc Chimie et de 

 Physique, 3rd series, t. xiv., 1845). We may add in praise 

 of M. Bouchardat's sagacity, that that skilful observer has 

 always considered these results as a proof that alcoholic 

 fermentation is dependent on the life of the yeast-cell, and 

 that a distinction should be made between the two orders of 

 fermentation. 



which that influence is noticed, was published in January, 1858, that is, 

 subsequently to our work on lactic fermentation, which appeared in Novem- 

 ber, 1857. In that work we established for the first time that the lactic 

 ferment is a living, organized being, that albuminous substances have no 

 share in the production of fermentation, and that they only serve as the 

 food of the ferment. M. Bechamp's note was even subsequent to our 

 first work on alcoholic fermentation, which appeared on December 2ist, 

 1857. It is since the appearance of these two works of ours that the pre- 

 ponderating influence ot the life of microscopic organism in the phenomena 

 of fermentation has been better understood. Immediately after their 

 appearance M. Bechamp, who from 1855 had made no observation on the 

 action of fungoid growths on sugar, although he had remarked their 

 presence, modified his former conclusions. (Comptcs rendus, January 

 4th, 1858.) 



*" There are two classes of ferments; the first, of which the yeast of 

 beer may be taken as the type, perpetuate and renew themselves if they 

 can find in the liquid in which they produce fermentation food enough 

 for their wants; the second, of which diastase is the type, always sacrifice 

 themselves in the exercise of their activity." (DUMAS, Comptes rendus d* 

 I 'Academic, t. Ixxv., p. 277, 1872.) 



