Vol. 6, 1920 
PHYSIOLOGY: F. G. BENEDICT 
7 
abridged method is very close. In a comparison recently made, covering 
53 days on which observations by both methods were available, it was 
found that on 32 days the result by the new and the old methods agreed 
within less than 1%, and on 45 days within less than 2%. It was found, 
also, that on the days in which the agreement was not good, some change 
in transparency appeared to be occurring which would reasonably account 
for the discrepancy on the ground that the value by the old method had 
been impaired thereby. 
The new method is applicable on many more days than the old, and it 
has the further advantage that several independent observations of the 
solar constant of radiation may be made by the new method on a single 
day of observation. We believe that by checking the new method against 
the old from time to time it will be possible to assure ourselves of the 
accuracy of it, and we propose to employ it principally, hereafter, in our 
determinations of the solar constant of radiation. 
THE BASAL METABOLISM OF BOYS FROM i TO 13 YEARS OF 
AGE 
By Francis G. Benedict 
Nutrition Laboratory, Carnegie Institution of Washington, Boston, 
Massachusetts 
Read before the Academy, November 10, 1919 
The Nutrition Laboratory has been occupied for a decade in an effort 
to chart the field of the basal metabolism of humans of both sexes and of 
all ages. By basal metabolism is meant the heat production for main- 
tenance during complete muscular repose and without active digestion. 
From a biometric analysis^ of the studies already made of men and women, 
it is clear that weight, stature, age, and sex all have an independent in- 
fluence upon the basal metabolism. 
With growing boys the rapid changes in weight, stature, and age make 
metabolism measurements of unusual interest. The data that are reported 
herewith, representing 128 observations on boys ranging in age from a few 
months to 13 years and above, were all obtained with the cooperation 
of Dr. Fritz B. Talbot of Boston and the detailed results of the investiga- 
tion will shortly be published in conjunction with him by the Carnegie 
Institution of Washington. 
The total calories per 24 hours referred to weight are indicated for all 
the subjects in the chart. A general inspection of this chart shows a dis- 
tinct trend which follows a reasonably regular course. The scatter of the 
points about this curve is perhaps surprisingly small, especially when we 
consider the usual scatter with adults. Indeed, until the collection of 
