587 



The account on page 640 of investigations at Halle and elseuliere 

 of the effects of fermentation upon the composition and digestibility of 

 wet feeding stufl's is interesting in its bearing upon the question of the 

 chemical changes in green fodder in the silo. 



Eecent investigations have made it clear that bacteria and other 

 so-called organized ferments are very active in the silo, that the chemical 

 changes which they bring about are complex and variable, and that the 

 effect upon the digestibility and nutritive value of the conn)oundsmay 

 be very disadvantageous. The feeding value of the compounds affected 

 by these ferments maybe diminished in four ways: (1) A considera- 

 ble quantity of nutritive material may be lost by decomposition. The 

 amount of this loss may be either inconsiderable or very large, accord- 

 ing to the nature of the fermentation. (2) Where the fermentation is 

 accom])anied by evolution of heat the potential energy of theresultiug 

 products in the silage will be less than that of the original compounds 

 by the equivalent of the amount of heat evolved. (3) The more soluble 

 and easily- digestible products are in general the ones most subject to 

 decomposition and hence the material which remains unacted upon may 

 be less digestible than the original material. The experimental results 

 bearing upon this phase of the general question are, however, somewhat 

 conflicting. (4) Products may be formed which are positively detri- 

 mental. 



In the present state of our knowledge we are able to speak of these 

 things only in a general way, but enough is known to make it certain 

 that a thorough study of fermentations, such as those which take place 

 in the silo, is greatly needed. The beginnings already made in this 

 direction in American and European stations and in biological and 

 chemical laboratories of other institutions are in the right direction, 

 but to get the definite and reliable results which are so pressingly 

 needed nothing less than the most patient and thorough work of the 

 specialists in bacteriology and biological chemistry will suffice. 



Here is a field of inquiry which presents manifold attractions to the 

 investigator. It is comparatively new, the research needed is of the 

 highest order as view^ed from the standpoint of abstract science, and 

 the results promise to be of the greatest practical value. — [W. O. A.] 



