524 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 
In analyzing the figures obtained in these experiments, one is con- 
fronted by the difficulty of selecting the proper normal value for com- 
parison. As previously stated, it is obvious that the only one that can 
be logically selected is that for January 6, since it was obtained imme- 
diately before the restriction in diet. Using this value, we find that 
the heat production per kilogram of body-weight per hour fell until 
on January 28 it was 13.3 per cent lower than it was on January 6. 
The heat production per square meter of body-surface per hour also 
fell until on January 28 it was 17.1 per cent lower than on January 6. 
With Squad A the computed heat values for the final experiment of 
February 2-3 gave values which indicated that there had been a de- 
crease of 19 per cent in the heat production per kilogram of body- 
weight over the initial value found on September 29-30. For the heat 
production per square meter of body-surface it was 23 per cent. These 
findings with Squad B of 13.3 and 17.1 per cent, respectively, for the 
same factors are not quite so large, but the loss in body-weight and 
what is, we believe, of still more importance, the loss of body-nitrogen 
was by no means so great as it was with Squad A. 
Using the normal values obtained with this squad in October, we 
may compute the total decrease in the heat output as shown by the 
value obtained on January 28. On this basis we find that there has 
been a decrease in the heat production from October 7 to January 28 
(including both the seasonal variation and the variation due to the 
restricted diet) of 22.7 per cent, and on the basis of the heat per square 
meter of body-surface 24.7 per cent. These values actually exceed 
somewhat those found with Squad A. Had it not been for the series 
of observations on Squad B with uncontrolled diet on November 3-4, 
November 17-18, December 15-16, and January 5-6, these values 
would have been extremely difficult to interpret. The difficulty of 
applying an arbitrary base-line or an arbitrary so-called ''standard" 
value to a series of experiments is apparent, even when group measure- 
ments are made. 
The general picture of reduction, then, is approximately what would 
be expected from the loss in body-weight and the loss in nitrogen with 
Squad B as compared with Squad A. Both show pronounced altera- 
tions of the basal metabolism as the result of the restricted diet. The 
decrease is not only absolute but relative, being from 13 and 23 per cent 
lower per kilogram of body-weight and from 17 and 25 per cent per 
square meter of body-surface. 
GENERAL CONSIDERATION OF THE EFFECT OF REDUCED DIET ON BASAL 
METABOLISM. 
From the net calories required for maintenance at the lower weight 
level, we inferred that the caloric requirement had been reduced very 
considerably, i. e., from a net intake of not far from 3,100 or even more 
calories to a net intake of 1,950 calories during the period of mainte- 
