232 ALCOHOL, VINEGAR, SAUER KRAUT, TOBACCO, SILAGE, FLAX. 



experimental jars in which chloroform vapor prevents the growth of 

 bacteria, although it allows the enzyme action to continue as usual. 

 It goes through a fermentation that is fairly typical, a fact that shows 

 that the essential phenomena of ensiling may be wholly the result of 

 these two sets of activities. 



The Action of Microorganisms. It was first thought that the 

 fermentation of silage was a bacterial action wholly, but further 

 study showed the fallacy of this conception. The original fer- 

 mentation, by which there is a rapid rise in temperature, cannot 

 be the result of bacterial growth, since it is too rapid and the 

 temperature rises too high. There is no evidence to suggest that 

 any bacteria can produce a rise as high as 150, a temperature that 

 destroys the life of most organisms. If the rise were due to bacteria 

 it would be rather slow, rising only as the bacteria had the oppor- 

 tunity to develop, while on the contrary it is very rapid. Finally 

 the possibility of making silage in a jar filled with chloroform vapor 

 shows that bacteria are not necessary for the phenomenon. 



But this does not by any means exclude the agency of micro- 

 organisms in the ordinary formation of silage. Bacteria are cer- 

 tainly present and, in some cases, they are present in great numbers. 

 Some bacteriologists have not been able to find them so very abun- 

 dantly, but this seems to be due to the fact that they did not use 

 favorable media in studying them, for when a medium is used 

 that is adapted to the silage bacteria, they are found in abundance. 

 Certainly, if they are present and develop during the fermentation, 

 they must have some effect upon the silage. One effect they cer- 

 tainly seem to have. The silage turns acid during the ensiling, and 

 this acidity appears here, as in other cases which we have noticed, to be 

 a means of preventing subsequent putrefactive changes. Without 

 doubt this acidity may be attributed in part, if not wholly, to acid- 

 forming bacteria growing in the silo. 



Further, there develop in the silage certain prominent flavors 

 which contribute largely to its value, and the source of these flavors 

 is as yet unknown. Aromatic flavors such as are found in silage do 

 not come from respiratory processes, nor do enzymes develop such 

 flavors, so far as is known. There are. some who think, however, 



