338 REPORT—1852, 
will be well to see how far the experiments with pigs afford us similar indi- 
cations in relation to the former one. 
The pig requires much less of mere du/k in his food than the ruminant 
animal. Indeed, the food of the pig, when on a liberal fattening diet, consists 
generally, weight for weight, of a much larger proportion of digestible or 
convertible: constituents, and contains much less of effete woody fibre than 
that of the sheep. Thus, whilst the food of the fattening sheep is principally 
composed of grass, hay and roots, with a comparatively small proportion of 
cake or corn, that of the fattening pig comprises a larger proportion of corn, 
which contains a comparatively small amount of indigestible woody fibre, 
and is comparatively abundant in starch, sugar, &c., and in highly nitro- 
genous compounds. Notwithstanding the generally richer character of his 
food, however, the fattening pig is found to consume a much larger quantity 
of dry substance in relation to his weight than the sheep. We should at 
least expect, therefore, that he would yield a greater proportion of increase, 
and this he is found to do. Such, indeed, is the greediness of the animal, 
and so much larger is the proportion of the food which he will consume 
beyond that which is necessary for the respiratory function, or for the 
formation of flesh, and which is therefore employed in storing up fat, that 
the amounts of non-nitrogenous matter consumed must obviously, in his 
case, have a less close numerical relationship to the requirements of the 
respiratory system than in that of the sheep. Hence, no doubt, is in part 
the reason that the exact indications of the figures of the Tables are, on the 
whole, not so consistent as with the sheep. The experiments with the pigs 
however bear testimony in the same direction as those with the sheep on 
the question now in discussion, and the evidence they afford on the point is, 
indeed, very conclusive. 
In the arrangement of the pig experiments the selection of the foods was 
made rather according to composition than to cost. In the first series (see 
Tables VI. and VII.) the foods chosen were— 
fi A mixture of equal parts of bean and lentil meal, as a highly nitrogenous 
ood. 
Indian corn meal, as the comparatively non-nitrogenous food. And— 
Bran, as containing a considerable amount of woody fibre. 
The series comprised twelve pens, in each of which three pigs were placed. 
In the first four pens, the bean and lentil mixture constituted the ad libitum 
food; in one of these it was given alone, and in the others with a limited 
amount of one or both respectively of the other two descriptions of food. 
In the second set of four pens, the Indian corn meal was the ad libitum food ; 
and it, in its turn, was in one case given alone, and in the others with a 
certain amount of the other or limited foods. In the third set of pens, bran 
was the ad libitum food ; the other two then constituting the fixed or limited 
food. In this way there was secured a great diversity in the proportion of 
the nitrogenous to the non-nitrogenous constituents of the food in the 
several pens ; and as the animals were allowed to fix for themselves the limit 
of their consumption, the results afford us the means of judging, whether in 
doing this, their natural instincts have Jed them to any uniformity in relation 
to their weights, in the amounts taken of either of these classes of constituents. 
In Table VI. are given the amounts of the nitrogenous and non-nitrogenous 
constituents respectively, consumed weekly by every 100 lbs. live weight of 
animal. In this Table we see at a glance, that although there are some 
apparent discrepancies, yet the figures in the column of mon-nitrogenous 
constituents are much more uniform than in that of the nitrogenous ones. 
And, as to the few apparent deviations from this uniformity, we think it 

