112 THE CHEMISTEY OP THE PAEM. 



The figures show in a striking manner the wide differ- 

 ences that exist amongst foods as to the proportion of 

 albuminoids which they supply. The differences are in 

 fact far greater than was formerly supposed, when it was 

 customary to assume that the whole of the nitrogen of 

 food was albuminoid. Mangels now appear as a food 

 very poor in albuminoids, whereas they were formerly 

 supposed to contain a sufficient proportion. The poverty 

 of a diet of roots and straw chaff in digestible albumin- 

 oids is the true reason of the excellent effects produced 

 by the addition of oil-cake or leguminous corn. Oil- 

 cake, peas, and beans, used under these circumstances, 

 have an effect far above their own intrinsic feeding value, 

 as their presence raises the character of the whole diet, 

 and enables the carbo-hydrates of the roots and straw to 

 contribute to the formation of carcase. If, on the other 

 hand, an animal is at pasture, or fed with clover hay, and 

 is thus receiving an abundance of albuminoids, the use 

 of oil-cake or beans will be without especial advantage to 

 the animal, and they may be economically replaced by 

 maize or other cereal grains. 



It should be recollected that the albuminoid ratio of a 

 food may be different for different animals if their powers 

 of digestion are unequal. Thus the same meadow hay 

 supplied to sheep and horses had for the former an albu- 

 minoid ratio of 1 : 9*1, and for the latter a ratio of 1 : 6*7. 

 The horse, as we have seen, digests the nitrogenous con- 

 stituents of hay nearly as well as the sheep, but fails in 

 digesting the non-nitrogenous constituents. Hay is thus 

 a more nitrogenous food for horses than for sheep. 



The proportion of albuminoids most suitable for various 

 diets will come under consideration in the next chapter. 



