IX.] 



VALUATION OF FEEDING STUFFS 



183 



is present in the form of non-protein compounds, as it is 

 also in cabbage and all other green foods. 



It is impossible to value feeding stuffs with the same 

 measure of precision which attaches to comparisons of 

 fertilisers, but certain estimates may be drawn up which 

 are useful in considering the purchase of foods of 

 the same class. Fats and carbohydrates may clearly be 

 compared together, since both sets of bodies are used 

 solely as fuel. Experiments which will be discussed 

 later show that fats give rise to about 2-3 times as much 

 heat as carbohydrates, whether compared in the calo- 

 rimeter or in the body, so that we may value i lb. of fat 

 at 2-3 times the value of i lb. of carbohydrate. Proteins 

 besides their value as fuel are also necessary to repair 

 waste ; while no relation depending upon principle can 

 be fixed between them and the carbohydrates, for 

 commercial purposes they may be taken as equal to 

 fats, ue. at 2-3 times the value of carbohydrates. Thus 

 if we wish to compare the values of decorticated cotton 

 cake and of gluten meal, we can proceed as follows : — 



It would be far more correct to consider the di- 

 gestible constituents only in such a valuation, in 

 which case the feeding stuffs set out above would 

 show 118 and 126 units respectively, figures which 

 ought not to be too widely departed from in the 

 relative prices given for the foods. In the market, 



