For purposes of discussion of the problems of meat production the term “condition” may be defined as the ratio of the amount of fat to the amount of non-fatty matter in the body of the living animal, and the term “fattening” as any alteration in this ratio. Such alteration may result from (a) increase, (b) decrease in the amount of fat, (c) increase, (d) decrease in the amount of non-fatty matter. This, of course, implies that fattening may be either positive or negative and that the “increase” may be mathematically a minus quantity.