Vol. 7, 1921 PHYSIOLOGY: BENEDICT, HENDRY, BAKER 
11 
For groups of girls, therefore, from 12 to 17 years of age the energy re- 
quirement for 10 hours of "bed rest" may be taken as 550 calories. The 
basal 24-hour heat production with all these groups of girls closely approxi- 
mated 1250 calories per individual, irrespective of age or weight. 
The computation of the heat per kilogram of body weight per 24 hours, 
the classic method of equalizing, in so far as possible, differences in the 
weights of the groups, showed that in general the younger the average 
age, the higher the heat production. Similarly, computations of the heat 
production per square meter of body surface (obtained from the Du Bois 
height-weight chart) indicated a distinct tendency for the higher values 
to be found with the younger girls. These data for the basal metabolism 
measurements are given in table 1 herewith. 
TABLE 1 
Basal Heat Production of Girls 12 to 17 Years of Age 
BASAL HEAT (COMPUTED)* 
AVERAGE 
PER 24 HOURS 
i 
AVERAGE 
BODY WEIGHT 
AVERAGE 
DATE 
AGE 
WITHOUT 
HEIGHT 
CLOTHING 
Per 
Per 
Per 
individual 
kilo 
sq. m. 
1920 
Yrs. 
Mo. 
Kgs. 
Cms. 
Cals. 
Cals. 
Cals. 
Jan. 
2- 3 
17 
0 
58.1 
163 
1258 
21.7 
777 
Jan. 
9-10 
15 
10 
53.6 
163 
1170 
21.8 
745 
Jan. 
16-17 
14 
10 
49.9 
160 
1254 
25.1 
830 
April 
9-10 
14 
1 
44.2 
155 
1266 
28.6 
911 
March 
19-20 
14 
0 
51.7 
161 
1331 
25.7 
876 
Jan. 
23-24 
13 
8 
50.0 
159 
1382 
27.6 
928 
Feb. 
13-14 
13 
4 
43.7 
153 
1188 
27.2 
867 
March 
12-13 
12 
10 
41 .0 
152 
1226 
29.9 
922 
March 
5- 6 
12 
2 
39.5 
150 
1180 
29.9 
915 
1 Eleven girls were studied on Jan. 16-17 and April 9-10; 12 girls on all other dates. 
All girls in the 15, 16 and 17 year old groups had reached puberty; none of the girls 
studied on April 9-10 and March 12-13 had reached puberty; 5 girls on Jan. 23-24, 
2 on March 19-20, 4 on Feb. 13-14, and 11 on March 5-6 had not reached puberty. 
2 Using a respiratory quotient of 0.79 and 3.086 calories as the calorific equivalent 
of a gram of carbon dioxide. 
The striking influence of age is shown by the values for the heat produc- 
tion per kilogram of body weight, which indicate a specific high metabo- 
lism with the younger ages. These values for the heat per kilogram have 
been plotted, referred to age, in figure 1, and a line representing the general 
trend of the metabolism has been laid on the chart. From this chart we 
have derived the predicted values for the heat per kilogram of body weight 
of girls, depending upon age, and these values we present in table 2 as 
representing the best available standard for predicting the heat produc- 
tion of young girls of this age-range. 
