SOME OE THE ANIMLiES FED AND SLAUGHTEEED AS HUMAN FOOD. 547 
food consumed by this single fattening Pig, there were produced 14-94 parts of dry 
substance of increase. Of these 14-94 parts of total dry increase, 13-2 were fat, 1-62 
nitrogenous compounds, and 0-11 mineral matter. Against these numbers we have, 
taking the average of all the other estimates (twenty-four in number, and comprising 
80 animals), 17-27 total dry increase for 100 of dry food; of which 16-81 are esti- 
mated as fat, 1-44 nitrogenous substance, and an insignificant amount of mineral matter. 
It is admitted that the estimates in Table X.IV. relating to the Sheep, show a higher 
proportion of mineral to other constituents, stored up, than was probably the fact. On 
the other hand, the estimates of assimilated mineral matter in the case of the Pigs are 
probably in error in the other direction. It is true, that Pigs, though young, if put upon 
highly fattening food will grow comparatively little in frame, whilst Sheep, fed as they 
now generally are at a comparatively early age, will develop more of hard bony struc- 
ture. It would be expected, therefore, that the proportion of mineral matter in the 
increase of fattening Sheep would be greater than that in fattening Pigs. Indeed, Table 
VII. shows the percentage of mineral matter, in the total carcasses, to be more than 
twice as much in the fattened Sheep analysed, as in the fat Pig. In the case of both 
Sheep and Oxen moreover, there seems to be a striking parallelism in the proportion of 
the mineral to the nitrogenous matters of growth ; whilst with the Pig, not only is the 
actual amount of mineral matter much less, but its proportion to the nitrogenous matters 
seems to decrease as the animals fatten. Thus, looking to the composition of the car- 
casses alone, in which there would be no error in the mineral matter as when the hair or 
wool with its extraneous dirt is brought into the calculation, it is found that the amount of 
mineral matter to 1 of nitrogenous substance, was — in the lean Ox 0-31, in the fat Ox 0-30, 
in the store Sheep 0-30, in the fat Sheep 0-30, and in the very fat Sheep 0-30. On the 
other hand, in the carcass of the store Pig, the proportion of mineral matter to 1 of 
nitrogenous substance was 0-183, and in that of the fat Pig it was less still, or 0-133. 
From these considerations it is obvious, that the amount of mineral matter in the increase 
of the fattening Pig, will be much less both in proportion to the total increase itself, and 
to the coincidently accumulated nitrogenous compounds, than in that of the Sheep. The 
distinctions which the Tables relating to the composition of increase show, between the 
two descriptions of animal in this respect, are then, without doubt, correct in the main ; — 
that is to say, at least in their direction^ though probably not in the degree which the 
actual figures indicate. It is pretty certain that the estimates of mineral matter in the 
increase of the Sheep are somewhat too high ; and unless it be admitted as probable, that 
Pigs rapidly increasing in weight under the fattening process, may sometimes not only 
not fix any mineral matter whatever, but even lose some of that ah-eady fixed, it must 
be concluded, that the Pig killed and analysed as fat, had too small a proportion of bony 
stiucture to be strictly comparable with the one analysed in the leaner state. 
It will be obvious, from the very nature of the subject, that these estimates of the 
composition of increase^ must only be taken as applicable for any general purposes, after 
due regard to the various qualifying circumstances which have been pointed out. 
