OF ANIMALS FED AND SLAUGHTERED AS HUMAN FOOD. 
883 
equal live-weight of pigs considerably less still. With each description of animal the 
quantity of phosphate is less in a given live-weight of the fatter than of the leaner 
individuals ; and this is especially so in the case of the pigs. In round numbers it 
may be said that 1,000 lbs. live-weight of oxen will carry off only 2 lbs., or less, of 
potash ; 1,000 lbs. of sheep from If to 1^ lb. ; and 1,000 lbs. of pigs about the same; 
in each case the less, the fatter the animal. Of the potash, as of the phosphoric acid, 
by far the larger proportion of the whole is in the carcass parts. The constituent 
coming next in amount is soda ; but with oxen the quantity in 1,000 lbs. live-weight 
does not reach 1-| lb., with sheep it is only about 1 lb., and with pigs about the same, 
or less in the fat condition. 
It may be said with regard to each description of animal that a given live-weight 
will contain less of every constituent the more it is matured or fattened. 
So far as the practical bearings of the subject are concerned, it will be seen that the 
production and sale of the animals of the farm carries off comparatively immaterial 
amounts of mineral constituents, but an equal weight of oxen more than the same 
weight of sheep, and an equal weight of sheep more than the same weight of pigs. 
Again, four-fifths of the whole, or even much more, will be phosphate of lime, and the 
amount of potash very small. The loss to the land, or to the manure from purchased 
food, will, however, be considerably more with growing than with only fattening 
animals. 
It is obvious, indeed, that the amount of mineral constituents lost to the farm by 
mere fattening increase will be almost insignificant. We have elsewhere estimated 
that the increase of oxen and sheep over the final four or six months of the fattening 
period, will not contain more than about 1^ per cent, of mineral matter; that of pigs 
over the usually shorter period not more than 1 per cent., and in the case of very fat 
animals less still. 
As conveying a somewhat more definite idea on the point, the amount of some of 
the most important mineral constituents that would be removed from an acre of fair 
average pasture and arable land, in animal increase and in some other products, may be 
compared. Such estimates can obviously be only approximate, and the quantities will 
be subject to considerable range of variation. Taking them as such, it may be stated 
in general terms that—of phosphoric acid an acre would lose more in milk, and four 
or five times as much in wheat or barley grain, or in hay, as in the fattening increase 
of oxen or sheep. Of lime the land would lose about twice as much in the animal in¬ 
crease as in milk, or as in wheat or barley grain, but, perhaps, not more than one-tenth 
as much as in hay. Lastly, of potash an acre would yield only a fraction of a pound 
in animal increase, six or eight times as much in milk, perhaps twenty or thirty times 
as much in wheat or barley grain, and more than one hundred times as much in hay. 
The loss to the land in the animal increase is, in fact, chiefly in phosphate of lime, 
in amount varying from 5 to 10 lbs. per acre. In milk the loss is higher in phos¬ 
phoric acid, less in lime, and more in potash. In wheat and barley grain the loss 
