and of their Increase lohilst Fattening. 
481 
of the 9"94 parts of p?oduced fat. There would thus be of 
ready-formed fat and starch, taken together, 28'11 parts out 
of 100 dry matter of food, directly engaged in the storing 
up in the body of the 13'2 parts of fat ; if we add to this 
1*73 parts of nitrogenous and mineral matters at the same time 
fixed in the increase, we have 29 "84 parts out of the 100 
of dry matter of food, directly contributing, in the sense sup- 
posed, to the production of only 14*94 parts of dry increase. In 
the particular sense here implied, therefore, only 70*1 G parts 
out of 100 dry matter of the food would be expired, perspired, 
or voided, without thus directly contributing to increase, in- 
stead of 85"06 parts — which represents the difference between the 
14"94 parts only of dry substance actually stored up, and 100 of 
dry matter of food consumed to produce it. 
Following the same line of illustration with all the other ex- 
periments with pigs, the average result obtained is, that 100 dry 
matter of food gave 16"04 parts of fat stored up, with only 3"96 
parts of ready-formed fatty matter in the food. At least 12"08 
parts must, therefore, have been formed from other substances. 
If from starch, it would require 30-2 parts of that substance for 
the formation of the 12*08 parts of produced fat. The ready- 
formed fat and the starch together would amount to 34'16 parts. 
There were, further, 1*36 part of nitrogenous and mineral 
matters assimilated. In all, therefore, 35'52 parts out of 100 of 
gross dry matter of food contributed in this comparatively direct 
manner, to the formation of 17 "3 parts of gross dry increase. 
It will be observed that assuming starch to be the source of 
the produced fat, as above described, there were almost exactly 
2 parts of dry substance of food thus directly engaged in con- 
tributing to the formation of 1 part of dry increase. It appears, 
too, that in the case of pigs fed on good fattening food, about 
one-third of the whole dry substance consumed may be so 
devoted. About two-thirds therefore will, if at all, only in a 
less direct manner, contribute to the production of increase. 
Of this a large proportion will serve, more or less directly, for 
respiration only, or for the supply of material for the transforma- 
tions constantly going on in the body independently of any 
permanent increase in its solid substance ; and, besides the 
matters voided as indigestible and necessarily effete, a quantity 
of digestible constituents, larger or smaller according to the 
character of the food, and to the excess of it consumed, will pass 
off unused and comparatively unchanged. 
From a knowledge of the general character of the fattening 
food of both oxen and sheep, considered in relation to the amount 
of increase it yields, and to the probable composition of that 
increase, it may be concluded that, in their case as well as in 
