202 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



to 1 : 8 or contracted to 1 : 4, the digestibility, and therefore the nutri- 

 tive value, of the fodder is interfered with if these limits be passed. 



In the case of hay, again, the amount of fatty constituents is to the 

 nitrogenous matters as 1 : 3.7. If this proportion be contracted to 1 : 2.2 

 the horse will still be able to accomplish its normal amounts of work ; but 

 if reduced below this for the horse, or below 1 : 3 for the ox, the full 

 nutritive value of the food will not be appropriated. These figures, of 

 course, refer to the digestible percentages of the fodders, and by referring 

 to the tables of the composition of the different food-stuffs, which will be 

 subsequently given, it will be found possible to construct dietary tables 

 according to the demands on the animal economy. 



It may thus be added to the general statements which have been 

 made in the early parts of this section that not only must all animals 

 receive representatives of the different food-constituents, but that the 

 herbivora must not receive more than eight or less than four parts of 

 non-nitrogenous matter to one of proteid, and not less than two parts 

 of proteid to one of fat. 



