868 
SIR J. B. LAWES AND DR. J. H. GILBERT ON THE COMPOSITION 
condensed view. We need only call attention here to some of the most prominent 
indications. 
It will be observed that there is a very much larger proportion of total fat than 
of total nitrogenous substance, in all the animals excepting the calf; that the per¬ 
centage of nitrogenous substance diminishes, and that of the fat greatly increases, as 
the animals mature ; also that the percentage of the total mineral matter decreases as 
the animals mature. 
It is obvious that the increase during the fattening period will consist in still less 
proportion of nitrogenous substance, and in still greater proportion of fat. In fact 
the amount of fat stored up may be 8 or 10 times as much as that of the nitrogenous 
substance ; and in the case of very fat pigs even more. The proportion of the total 
mineral matter, like that of the nitrogenous substance, is also much less in the 
fattening increase of the animal, than in the entire body. 
Calculation further showed that the proportion of the nitrogenous substance of the 
food which was finally retained was very small. For example, sheep fattening on a 
good mixed ration will probably so retain in increase less than 5, or even less than 
4 per cent, of the nitrogenous substance consumed in their food. If, however, the 
food is low in nitrogenous substance, more than 5 per cent, of that consumed may be 
stored up. In the case of pigs a larger proportion of the nitrogenous substance of the 
food is stored up, perhaps on the average 7 \ per cent. If the food be low in nitrogen, 
consisting chiefly of cereal grain for example, perhaps nearly 10 per cent., or if high 
in nitrogen perhaps not more than 5 per cent, of that consumed will be finally 
retained. 
The amount of fat stored up was shown to be very much greater than the amount 
of ready formed fat in the food. Fat was, therefore, largely formed within the body ; 
and the results led to the conclusion that it was largely produced from carbohydrates. 
It has been stated that the amount of mineral matter stored up in fattening 
increase is very small. Further, the proportion of that consumed which is retained 
depends so much on the character of the food that no general estimate can be safely 
given. The amount is at any rate almost immaterial, and the proportion will probably 
be always considerably less than that of the consumed nitrogenous substance retained. 
In connexion with this point it may be mentioned that in the case of each of the 
oxen and sheep the amount of mineral matter to one of nitrogenous substance was 
almost exactly 0'3 in the collective carcass parts, but it was lower in the other parts, 
and in the entire bodies. The results which it is the special object of the present 
communication to put on record will throw more light on the mineral composition of 
the animals. 
Before closing this summary statement, and entering upon the special subject- 
matter of the present paper, brief reference should be made to some conclusions of 
importance to which the consideration of the composition of the animals as so far 
given, led. 
