AgricultiLval Chemistry. — Pig Feeding. 519 



In Tables XXII., XXIII., XXIV., XXV., XXVI., and 

 XXVII., we have then, for each Series, the actual facts of Tables 

 XIX., XX., and XXI., reduced by calculation to one uniform 

 standard of comparison. That is to say, we have in Tables 

 XXII., XXIII., and XXIV.,* for the three Series respectively, 

 the amounts of the fresh food, and of its various constituents, 

 consumed iceekly per 100 lbs. live weight of animal in each pen, 

 instead of, as in the previous ones, the actual quantity of food, or 

 of its constituents, consumed per pen during the ivliole course of 

 the experiment. And again, we have, in Tables XXV., XXVI., 

 and XXVII. ,t the amounts of the foods, or their constituents, con- 

 sumed to produce 100 lbs. increase in live loeight, instead of, the 

 actual amounts consumed, to produce the actual amount of increase 

 obtained per pen. We have in previous papers, when adopting 

 these methods of representing the results of feeding experiments, 

 explained the general principle upon which such Tables are 

 calculated, and we shall not therefore repeat those explanations 

 here. We may, however, a little further describe the plan of the 

 Tables as they stand — as well as the materials whence some of 

 their contents have been derived. 



It will be seen, that each of the six Tables, whether relating 

 to the amounts of food, &c., consumed weekly per 100 lbs. live 

 weight of animal, or the amounts consumed to produce 100 lbs. 

 gross increase in weight, is divided into two " Divisions." 

 Division 1, in every case, gives what may be called the results of 

 direct experiment — that is to say, the amounts of fresh food con- 

 sumed, or of those constituents which are calculated directly from 

 the quantities of the latter and the Tables of their per-centage 

 composition, as determined by actual analysis. The constituents 

 given in this Division 1, are — the Fresh food^ the Gross dry 

 matter^ the Mineral matter^ the Nitrogen^ and the Fatty matter. In 

 Division 2, we have — the Dry organic matter, the Nitrogenous 

 substance, the Total non-nitrvgenous substance, the Non-nitro- 

 genous substance not Fat, and with these (which, as will be readily 

 understood, are derived by calculation from those in Division 1), 

 the Fatty matter is repeated in this Division, for the convenience 

 of comparison with them. The dry organic matter, is obtained 

 by deducting the mineral matter from the gross dry substance — 

 the nitrogenous substance, by multiplying the nitrogen by 6*3, 

 on the assumption that it existed in the foods as protein com- 

 pounds — a method which we think sufficiently accurate for our 

 present purpose. The total non-nitrogenous substance, is obtained 

 by deducting the nitrogenous substance from the dry organic 

 matter — and the non-nitrogenous substance not fat, by deducting 

 the fatty matter from the total non-nitrogenous substance. 



* See also Diagram I. 



7 See also Diagram II. 



