DIGESTIBILITY OF FOODS 141 



If the mass is weighted as soon as 140"* — 160° Fahr. 

 is reached, " sweet silage " will result, the high 

 temperature having been fatal to the bacteria which 

 produce an acid fermentation. 



In making silage the loss of soHd matter falls chiefly 

 on the carbohydrates. The total nitrogen is scarcely 

 altered in quantity, but a considerable part of the 

 albuminoids is destroyed, the nitrogen being found in 

 the silage as amides, or as ammonium salts. In the 

 case of " sour silage" one-third of the albuminoids is 

 not unfrequently destroyed. In making sweet silage 

 there is a smaller destruction of albuminoids, but they 

 become much less digestible. The loss of solid matter 

 in the silo is greater in proportion to the air admitted. 

 It is least when the material is sufficiently moist and 

 is firmly consolidated. The loss is less in large silos 

 than in small. 



In. stack silage the outside portion and the inner 

 mass are of very different character, air being freely 

 present on the outside, but nearly excluded in the 

 solid interior. The character of the inner mass 

 depends on the degree of moisture, the loose or close 

 packing of the material, and the speed with which 

 the stack is built and subjected to pressure. 



Digestibility of Foods. — Our knowledge concerning 

 the digestion of food by farm animals is almost entirely 

 derived from German investigations ; much information 

 has already been obtained upon this subject, though a 

 great deal yet remains to be accomplished. The 

 general method of investigation has been to supply an 

 animal with weighed quantities of food, the composition 

 of which has been ascertained by chemical analysis. 



