48 SILOS, ENSILAGE AKD SILAGEo 



each fermentation was expressed by a chemical formula, 

 or equation, indicating the supposed rearrangement of 

 the elements involved in the process. 



In regard to these equations Pasteur says : " Orig- 

 inally, 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 >\ ell-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 essen- 

 tially 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 fermenta- 

 tion may be assigned an equation, in a general sort of a 

 way ; an equation, however, which, in numerous points 

 of detail, is liable to the thousand variations connected 

 with the phenomena of life. 



"Moreover, there will be as many distinct fermenta- 

 tions brought about by one ferment, as there are ferment- 

 able substances capable of supplying the carbon element 

 of the food of that same ferment, in the same way that 

 the equation of the nutrition of an animal will vary 

 with the nature of the food which it consumes. 



"As regards fermentation producing alcohol, which 

 may be effected by several different ferments, there will 

 be, in the case of a given sugar, as many general equa- 

 tions as there are ferments, whether they be ferment- 

 cells, properly so called, or cells of the organs of living 

 beings functioning as ferments. In the same way the 

 equation of nutrition varies in the case of different ani- 

 mals nourished on the same food. And it is from the 

 same reason that ordinary wort produces such a variety 

 of beers when treated with the numerous alcoholic fer- 

 ments which we have described. These remarks are 

 applicable to all ferments alike ; for instance, butyric 



