3O2 AGRICULTURAL BACTERIOLOGY. 



in cheeses. The fact that the oxygen was used up prevented 

 the growth of the ordinary bacteria of decay, and consequently 

 the material might remain sweet for a long time. 



Such an explanation has been chiefly the result of hypothe- 

 sis, and has never been demonstrated by any actual study of 

 silage. It has been the basis of various attempts to explain 

 the origin of silage and the different changes occurring in the 

 chemical nature of the carbohydrates and albuminoids. It is 

 true that bacteria may be found in abundance in silage under 

 ordinary conditions, and they are even more noticeable under 

 unusual conditions. It has been therefore tacitly assumed 

 that these are the real causes of the fermentation. 



Non-bacterial Processes. But here, as in the tobacco-curing, 

 it is becoming manifest that the importance of bacterial action 

 has been exaggerated, and that perhaps bacteria have nothing 

 to do with the formation of silage. In the first place it is quite 

 evident that the original rise in temperature cannot be due to 

 bacterial action. The rise in temperature is too great. While 

 it has been recently shown that some bacteria may live at 

 temperatures as high as 140 F., it is very improbable that a 

 temperature of 150 F. could be produced by their growth. 

 This temperature indeed destroys most bacteria, and no one 

 would to-day believe that this original heating can be ac- 

 counted for by the growth of bacteria. Moreover, the heating 

 takes place much too rapidly for such an explanation. If 

 bacteria were its cause the heat would develop slowly and only 

 as the bacteria have a chance to grow ; but in reality the rise 

 in temperature in the silo is very rapid, much too rapid to be 

 accounted for by bacterial growth. Lastly, it has been shown 

 by Babcock and Russell, that typical silage may be formed 

 under conditions which prevent the growth of microorganisms. 

 If ensilage material be placed in proper vessels and in an at- 

 mosphere saturated with ether vapor, which is supposed to 

 prevent the growth of bacteria entirely, the material goes 

 through a typical fermentation and becomes normal silage. 



