SELECTION OF FOOD. 47 



tuents ? " From the teaching of experience, which here 

 can alone direct us, we may learn that for moderate 

 work, it should not exceed that which is contained in 

 oats, namely, 10 to 47 (about). To find the maximum, 

 we may assume a diet of four parts of oats and one part 

 of beans as given in England to hardworked animals ; 

 this will give us the proportion of 10 to 38 (about). 



To determine the maximum amount of nitrogenous 

 food, I think, we may safely assume it to be about that 

 contained in 20 Ibs. of oats, namely, 2 Ibs. (about). If we 

 are forced, by circumstances, to use a grain, such as gram, 

 or kulthee, which is too rich in nitrogen, we should do so 

 at the expense of the starch, but should, on no account, 

 exceed the amount of nitrogen already laid down, for if 

 we do so, the excess will tend to produce the derange- 

 ments of the system, which have been already mentioned. 

 Respecting the supply of fat, I am unable to say 

 anything more definite than I have done in the previous 

 pages of this chapter. Dr. Parkes' proposition, that 

 " if men are undergoing great exertion, they take more 

 food, and if they can obtain it, the increase is especially 

 in the classes of albuminates and fats," holds equally 

 well with regard to horses. 



Hay and Grass. We may consider these two to be 

 identically the same food, except that the former con- 

 tains a less proportion of water than the latter. 



I have previously argued that a horse should get a 

 full supply of hay under all circumstances, except when 

 he is unable to take sufficient exercise. 



A horse omitting exceptional cases evinces a marked 

 preference for corn compared to hay; hence we may 



