294 Royal Society :■ — 



and fat lamb contained about 30 per cent., the entire body of the 

 fat sheep 35-1- per cent., that of the very fat sheep 45|- per cent., and 

 that of the moderately fat pig A2\ per cent, of dry fat. 



The average composition of the six animals assumed to be well 

 fattened, showed, in round numbers, 3 per cent, of mineral matter, 

 \2\ per cent, of nitrogenous compounds, and 33 per cent, of fat, in 

 their standing or fasted live-weight. 



All the experimental evidence conspired to show, that the so- 

 called "fattening" of the animals, was properly so designated. 

 During the feeding or fattening process, the per-centag« of the col- 

 lective dry substance of the body considerably increased ; and the 

 fatty matter accumulated in much larger proportion than the nitro- 

 genous compounds. The increase itself, must therefore show a 

 less per-centage of nitrogenous substance (and of mineral matter 

 also), and a higher one of both fat and total dry substance, than the 

 whole body of the fattened animal. 



The knowledge thus acquired of the composition of animals in 

 different conditions of maturity, was next employed as a means of 

 estimating the composition of the increase gained in passing from 

 one given point of progress to another. 



To this end, the composition of the animals analysed in the lean 

 condition, was applied to the known weights of numbers of animals 

 of the same description, assumed to be in a similar lean condition ; 

 and the composition of the fat animals analysed, was in like manner 

 applied to the weights of the same series of animals after being 

 fattened. Deducting the amount of the respective constituents in 

 the lean animals, from that of the corresponding constituents in the 

 fat ones, the actual amount of each constituent gained was deter- 

 mined. The weight of the gross increase being also known, its 

 estimated per-centage composition was thus a matter of easy calcu- 

 lation. The composition of the increase of 98 fattening oxen, 349 

 fattening sheep, and 80 fattening pigs (each divided into immerous 

 lots), was estimated in the manner indicated ; and as a control, 

 a statement is given of the composition of the increase of the single 

 analysed fat pig, which, at the time it was put to fatten, corre- 

 sponded in weight and other particulars very closely with the one 

 analysed in the lean condition. 



It is concluded, that the increase in weight of oxen, taken over 

 six months or more of the final fattening period, may be estimated 

 to contain from 70 to 75 per cent, of total dry substance ; of which 

 60 to 65 parts will be fat, 7 to 8 parts nitrogenous substance, and 

 1 to 1^ mineral matter. 



On the same plan of calculation, the final increase of sheep, 

 feeding liberally during several months, will probably consist of 75 

 per cent., or more, of total dry substance ; of this, 65 to 70 parts 

 will be fat, 7 to 8 parts nitrogenous compounds, and perhaps 1^ part 

 mineral matter. 



The increase oipigs, during the final two or three months of feeding 

 for fresh pork, may be taken at 70 to 75 per cent, total dry sub- 

 stance, 65 to 70 per cent, fat, 6 to 8 per cent, nitrogenous substance. 



