THE CHEMISTRY OP THE FAEM. 



or as ammonium salts. In the case of " sour silage " 

 one-third of the albuminoids is not unfrequently de- 

 stroyed. In making sweefc silage there is, apparently, a 

 smaller destruction of albuminoids. The final product, 

 in this case, contains a larger proportion of soluble carbo- 

 hydrates, and little or no acid. The total loss of solid 

 matter is probably greater in making sweet, than in 

 making sour silage. 



Digestibility of Poods. 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. During this 

 experimental diet the solid excrements are collected and 

 weighed, and are finally analysed by the same chemical 

 methods previously applied to the food. Subject, there- 

 fore, to certain small corrections for intestinal secretions, 

 we obtain by this plan the amount of each constituent of 

 the food which has passed through the animal unabsorbed, 

 and by difference the amount digested. The proportion 

 of each constituent digested for 100 supplied in the food 

 is known as its " digestion coefficient." 



1. Experiments with Ruminants. Ruminating animals 

 possess an extensive digesting apparatus, consisting of 

 the well-known four stomachs, in addition to the intesti- 

 nal organs. Food takes a considerable time in passing 



* The information given in this section is taken to a great extent from 

 the admirable work of Dr. E. Wolff, " Die Ernahrung der Landwirth- 

 schaftlichen Nutzthiere,'' and its valuable Supplement. 



