94 AGRICULTURE. [CH. 



food. You must therefore fully realize the fact, that 

 although food is capable of yielding a certain in- 

 crease of live weight, the result actually obtained 

 depends in part upon the rate of supply. 



198. It was at one time generally considered that 

 the percentage of nitrogenous, and non-nitrogenous 

 matter in a food, indicated its powers of producing 

 flesh and fat respectively. We have proved by experi- 

 ment the actual feeding powers of different kinds of 

 food (194), but this does not support the opinion, 

 that analysis now indicates the quantity of flesh and fat 

 which will be produced by a food. If, however, we 

 know what any food of a given quality will produce, 

 we may rely with confidence upon an analysis showing, 

 whether any particular sample is likely to produce 

 larger or smaller results. Analysis is a safe guide for 

 determining the difference in value between two 

 samples of food, say of linseed cake ; but we must rely 

 upon actual experiment for proving its value as food. 

 This will be more fully confirmed by the facts stated 

 in the next paragraph. 



199. It has been shown by repeated trials that by a 

 judicious combination of different kinds of food, 

 we can obtain a much larger production of flesh and 

 fat, than by using the same quantity of the same food 

 separately from each other. For instance, it has been 

 stated (194) that 8 Ibs. of beans or 6 Ibs. of linseed 

 cake are each capable of producing i Ib. of increase 

 in live weight, but it has also been shown by direct 

 experiment, that when these foods are mixed and given 

 together, then we just get double the produce. Thus 

 8 Ibs. of beans would produce one pound increase, 

 and 6 Ibs. of linseed cake would produce a second 

 pound, but if the beans and linseed cake are given as 

 a mixed food, they produce 4 Ibs. increase of live 

 weight. In forming an estimate of the results which 

 are likely to arise from the use of any artificial or 

 supplemental food, it must therefore be borne in mind, 



