106 
PHYSIOLOGY: F. G. BENEDICT 
study of energy requirements and transformations in the living or- 
ganism, but as experimental evidence accumulated, the validity of this 
so-called 4aw of surface area' has been frequently called into question. 
An extended series of observations on 89 men and 68 women, all of 
them normal individuals in presumably good health, together with 
observations upon a group of athletes, a large number of new-born 
infants, normal infants under one year, and atrophic infants, and 
particularly a recent 31-day study of a fasting man, have given us 
data which warrant a reconsideration of the factors affecting basal 
metabolism. 
When all of the observations on the normal men and women are plotted 
on charts, it is seen that there is no direct relationship between body 
weight and the total metabolism other than that, in general, people of 
large body weight have a greater metabolism than smaller individuals. 
However, there are so large a number of exceptions to this general rule 
that nothing approximating a physiological law can be derived from these 
observations. The same is true with regard to the computations of the 
heat production per kilogram of body weight, for the widest variations 
are found with our so-called normal people, with no tendency towards 
uniformity. Furthermore, it has been shown in a foregoing article that 
the total metaboHsm and the metabolism per kilogram of body weight 
are distinctly larger with athletes than with normal individuals. In all 
of these comparisons the differences between men and women have been 
recognized; hence separate plots for men and women have been made. 
It has been practically impossible to make direct surface measure- 
ments of the men and women that we have studied, and we have relied, 
as have all physiologists hitherto, upon the commonly accepted formula 
of Meeh, in which the body surface is considered to be the cube root of 
the square of the weight multiplied by the constant 12.312. For infants 
the slightly smaller constant of 10.3, determined by Lissauer, has been 
accepted as the best available. Using Meeh's formula, we find that the 
metabolism of normal men, as computed from the body surface and 
expressed in calories per square meter of body surface per 24 hours, 
ranged from 693 to 958 calories. Since, according to the currently ac- 
cepted belief in the constancy of heat production per square meter of 
body surface, we would expect to find constant values with all individuals, 
irrespective of size, it can be seen that this variation is extraordinarily 
large. It should furthermore be stated that both of these extremes 
were found with non-athletic individuals. With women the range 
was from 633 calories per square meter per 24 hours to 906 calories. 
