OHAP. v. HOW TO COMPARE THE VALUES OF FOODS. 995 



oxen appear less decisive, and it is easy to quote results which shall 

 show either a great advantage or no advantage from the employment of 

 a very nitrogenous diet. Such experiments are, however, very seldom 

 fairly made : the comparison is usually between cake and corn, and 

 here the nitrogenous diet has all the advantage of a considerable 

 supply of oil in the food, while the diet poor in nitrogen contains but 

 little fat, and this fact alone may be quite sufficient to determine a 

 result in favour of the cake. The real advantage to be gained by the 

 use of cake is that, being a very concentrated food, it enables us to 

 prepare a fattening diet from such poor materials as mangel and 

 straw-chaff. 



" If we are asked, however, what foods at the present time (1891 92) 

 are the most economical to fatten on, we repry without hesitation the 

 nitrogenous foods, and especially cotton cake. We answer thus not 

 because of any special superiority in the fattening quality of nitro- 

 genous foods, but because when a farmer feeds largely with cake, or 

 with other nitrogenous food, he obtains, in addition to a fat animal, 

 a very valuable manure. This fact will remain only while the prices 

 of such foods as cotton cake, beans, peas, and lentils are so near to 

 those of the cereal grains. If the former foods were considerably to 

 rise in value the advantage of using them would cease. As it is the 

 value of the manure which turns the scale in favour of the nitrogenous 

 foods, it must of course be borne in mind that to secure this advantage 

 the manure must be protected from rain ; if this is neglected, the 

 cheapest fattening food, as maize, may prove the most economical." 



From the foregoing remarks by Warington it will have been 

 gathered that for the purpose of feeding a fattening animal, the 

 question of cost, rather than of mere composition, comes into con- 

 sideration and it may happen that sometimes it is more economical 

 to purchase a highly nitrogenous food for fattening purposes, and 

 sometimes on the other hand more economical to purchase a food that 

 is essentially starchy or " carbonaceous." Eeaders who have carefully 

 pondered over the pages we have quoted from Warington, should 

 now be in no great difficulty as to the principles on which, for 

 fattening purposes, to compare a food ; but for the sake of those who 

 may desire ready and simple instructions for forming a rough idea of 

 the comparative values of different feeding stuffs of known chemical 

 composition in the light of which to compare their prices, we would 

 give the following plan. It is true that it ignores the question of 

 relative digestibility. But relative digestibility, although investigated, 

 as has already been shown, by various experimenters, must necessarily 

 depend upon a variety of causes prominent among which are the 

 time of feeding and quantity fed, as well as the condition of the 

 animal. For the practical purpose of comparing the approximate 

 values of foods this question may be for the moment ignored, and a 

 little reflection on the part of any one with but a small knowledge of 

 physiology, chemistry, and arithmetic, will show that little practical 

 effect arises from leaving it aside. The manurial value, it should be 



3 s '2 



