470 On the Comjmition of Oxen, Sheep, and Pigs, 
sumed ; (2.) the probable amount of each constituent stored up 
for 100 of total dry substance of food consumed ; (3.) the relation 
of the amount of fat stored up, to that of the ready -formed fat in 
the food. 
1. Amounts of mineral matter, nitrogenous compounds, non-nitroge- 
, nous substance, and total dry substance, stored up in increase 
for 100 of each consumed. 
In Table XVII. are recorded the estimates under this head 
relating to sheep, and in Table XVIII. those relating to pigs. 
There is evidence that, other things being equal, a highly 
nitrogenous food may give a tendency to a comparatively large 
increase in frame and flesh. At the same time, observation 
leads to the conclusion, that with animals fattening under or- 
dinary conditions, this tendency will not increase in anything 
like a numerical proportion to the increased proportion of nitro- 
genous constituents, supposing these to be consumed in excessive 
amount. The proportion of the nitrogenous matters in the 
increase is probably more affected by the age and habits of 
the animal than by their proportion in the food — provided of 
course that they are not in defective amount. Hence, and owing 
also to the small proportion of the respective constituents of the 
food finally retained in the increase, any error arising from 
adopting the same composition for the final weights of animals 
fattened on very various foods, is immaterial in forming merely 
general and average estimates of the proportion of the con- 
sumed constituents that will be stored up in the increase. 
Taking the figures in Table XVII. as they stand, the average 
of the numerous estimates relating to sheep, shows rather more 
than 3 per cent, of the consumed mineral matter, to be retained 
in the increase of the animal. Assuming the due correction on 
account of the extraneous matter in the ash of the wool of the 
sheep analysed, the result would show an average of less than 
3 per cent. In Class IV. dry food ahme was given, and the 
projiortion of mineral matter to digestible organic substance in 
the food was very large. Hence, the proportion of the consumed 
mineral matter reckoned to be stored up in the increase is com- 
paratively very small — namely, only 1*G8 per cent. 
Upon the whole it may be concluded, as an average estimate 
for sheep fattening for the butcher on a good mixed diet of dry 
and succulent food, that they will not carry off" more, and per- 
haps frequently less, than 3 per cent, of the consumed mineral 
matter. Were it not that sheep are now generally fattened when 
still young and growing, the proportion retained in the increase 
during the period of fattening, would probably be extremely 
small. In fact, it can hardly be greatej, on the average, than 
above 
