A knowledge of the quantitative relation of the organs or parts, and of the ultimate and proximate composition, of animal bodies, is of great interest in many points of view. More or less accurate conceptions on these subjects, are essential to the Chemical Physiologist, in determining the relations of the system, to the matters ingested as food; nor is such knowledge an unimportant element in studying the changes which the latter undergo, and the offices they subserve, in their passage through the body. Especially, is a knowledge of the general composition of the animals slaughtered as human food, of great importance in the application of Chemistry and Physiology to Dietetics. This, indeed, is a branch of applied physiology, so to speak, which, owing in great part to the attention drawn to it by the labours of Boussingault, Mulder, and Liebig, from fifteen to twenty years ago, may be said to have entered upon a new era about that period. It is, moreover, daily gaining ground, both with the Physician and the Economist. To the Farmer, too, who is engaged in producing animal food for the consumption of the community at large, it is very desirable to know something of the chemical relations of the substance so produced and sold, to the constituents expended in producing it. In other words, he should possess some data for determining—what is the probable proportion of the consumed food, or of its several constituents, which he recovers in the form of meat ?-—how much he may calculate as manure ?—and how much as expenditure or loss by the feeding process ?