SILOS, ENSILAGE AND SILAGE. 39 



CHAPTER IV. 



FERMENTATION. 



In the ensilage of green fodder, as in the allied sys- 

 tems of preparing cattle feed, to which we have called 

 attention, various kinds of fermentation take place, to 

 a greater or less extent, which have an influence on the 

 quality and feeding value of the silage, and from a prac- 

 tical stand-point it becomes a matter of the first import- 

 ance that the causes and conditions involved in these 

 changes in the constitution of the preserved fodder are 

 clearly apprehended. The vague and incorrect popular 

 notions that prevail in regard to the processes of fer- 

 mentation and putrefaction lead to errors in practice, 

 from a false interpretation of the results obtained. 



In the first attempts to preserve green fodder in pits, 

 and even in the storing of grain, it was naturally assumed 

 that the air was the sole cause of putrefaction and decay, 

 and that the exclusion of the air was the essential condi- 

 tion for the preservation of articles of food that were 

 observed to decay when exposed to ordinary atmospheric 

 conditions. 



This empirical assumption was not only a plausible 

 explanation of the observed facts, but it was apparently 

 confirmed by the earlier investigations of science relating 

 to the phenomena of fermentation. Gay-Lussac proved 

 that "perfectly pure grape juice does not ferment unless 

 the process has been started by at least temporary con- 

 tact with ordinary air."* 



It was found that the solid particles of yeast, a well- 

 known active ferment, could be separated from the 

 liquid in which they were diffused, and Liebig claimed 



* Encycl. Brit. 9th Ed., vol. IX, p. 94. 



