CROP CHEMISTRY 



127 



convert part of the sugar into lactic acid. There are also 

 small amounts of butvric and some other acids formed, the 

 total acidity amounting to not more than 2 per cent, nor 

 usually less than 1 per cent. It is sometimes stated that these 

 acid changes are due not to bacteria but to intermolecular 

 respiration in the plant cells. Whether caused by bacteria 

 or intermolecular respiration, the accumulation of acid 

 stops the process, thus accounting for the maxmium of 

 2 per cent. acid. 



Fig. 31.— Silos. 



In addition to these changes there is also a loss of protein 

 and a formation of amides, possibly due to enzyme changes 

 analogous to the usual hydrolytic changes of protein within 

 the plant. Moreoever, some nitrogenous material decomposes 

 to ammonia, which forms salts with the acids present. Crude 

 fiber is softened and made more digestible, being partly 

 hydrolyzed in all probability. Other compounds in the 

 nature of volatile oils are formed, which add to the palata- 

 bility of the material. There is also a complete decomposition 

 of some- of the organic material. There is oxidation to carbon 

 dioxide and water, either by bacteria or oxidases, resulting 

 in a loss of dry matter amounting to 10 or 15 per cent. 



