THE DISTRIBUTION OF THE CHROMOPROTEINS, HEMOGLOBIN, MYOGLOBIN, AND CYTOCHROME c, IN THE TISSUES OF DIFFERENT SPECIES, AND THE RELATIONSHIP OF THE TOTAL CONTENT OF EACH CHROMOPROTEIN TO BODY MASS

Abstract

It is recognized that the over-all energy metabolism and, hence, the oxygen consumption bear a relationship of proportionality, not to body mass, but to a fractional exponent of this quantity. The skin surface area has a similar mathematical relation to the body mass. Thus, approximately equal values for caloric output (heat loss) or for oxygen intake per unit time are obtainable in species of different size, when these measurements are related either to a fractional exponent of their body masses (2, 3) or to their measured or calculated surface areas (4, 5). One avoids the direction of thought into unproductive channels by not pursuing the academic arguments (2, 3) as to which of these bases of reference (fractional exponent of body mass or surface area) is the more correct or valid in expressing the basal metabolism. On the whole, similar deductions can be arrived at from each empirical reference base, and each suffers from similar disadvantages and defects, which are largely owing to the fact that they appear to support a concept, very probably incorrect, that all kinds of protoplasm are the same. Nevertheless, valuable clinical inferences have been made in man by the use of the surface area base, and, without undue faith in their ultimate significance, both surface area and fractional exponent of the body mass are of service in the interpretation of the over-all metabolism of different species. With reference to specific metabolites or some of the agencies of metabolism and their relationship to body mass, the present knowledge is fragmentary. Dreyer et al. (6, 7), who first introduced the fractional expo-