It is a phenomenon general in mammals and other classes of the animal kingdom that metabolic rate per unit weight decreases with increasing body size. This is expressed in the surface rule of Rubner who stated that metabolic rate decreases per unit weight, but is constant per unit surface. More recent investigations (Brody, 1945 ; Kleiber, 1947) indicate that interspecifically, i.e., comparing mature animals of different species, basal metabolic rate in mammals is proportional rather to a % power of weight than to surface or the % power of weight. Intraspecifically, i.e., comparing animals of different body size within the same species, the surface rule applies to the general trend of the size-metabolism relation in rats, although qualifications have to be made in detail (Bertalanffy, Miiller and Racine, unpublished data). These complications, however, do not alter the fundamental fact of the decrease in weight-specific metabolic rate with increasing body size.However, we do not have a satisfactory explanation for this phenomenon.

No abstract

No abstract

No abstract

No abstract