LEAN BODY MASS

Abstract

MORE THAN a hundred years ago, von Bezold¹ enunciated a fundamental concept regarding body composition. He stated that every animal possesses a normal water, organic matter, and salt content which is characteristic of its species and age. In the process of maturation the changes which occur in the composition of mammals, birds, and amphibians were summarized as consisting of (a) a decrease in water content, beginning in the embryo and continuing up to the peak of early growth; (b) an increase in organic matter, which occurs at the greatest rate during the initial period of growth following birth, and (c) a marked increase in mineral content during the first period of autonomous life. Determinations were not made, however, of the fat content of the animals studied. Since the presence of variable quantities of fat may render meaningless a comparison of percentage weights of various components of the whole body,