498 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



heat production per square meter per hour for the squad was 39.5 

 calories. The sHghtly higher value obtained in the chamber may possibly 

 be explained on the ground that it is not a true post-absorptive value, 

 since the men had supper at 5 o'clock and the minimum metabolism 

 was often found about 2 or 3 o'clock in the morning. To offset this we 

 have the fact that the values were for the most part obtained during 

 deep sleep. The agreement between the two values, 40.8 and 39.5 

 calories, may be said to be, on the whole, as close as one could expect. 



The values found with Squad B are of special interest, for one of the 

 chief reasons for using Squad B throughout this experiment at the 

 expense of a large amount of time and labor, was not only to obtain 

 a basal value for comparison, but to study possible seasonal varia- 

 tions in the various factors measured. As pointed out in an earlier 

 section, when the men returned from their summer vacation, in the 

 latter part of September, they came for the most part from Y.M.C A. 

 camps and active outdoor work. They immediately began an entirely 

 new routine, living more or less indoors, studying late at night, and 

 sleeping in the college dormitories. If there is, then, a normal seasonal 

 variation in the metabolism, such studies as were made with Squad B 

 would reveal it. The metabolism of Squad B as measured in the group 

 respiration chamber throws considerable light upon this point. On 

 October 6-7 (one week after the normal experiment with Squad A), 

 Squad B showed a heat output per kilogram of body-weight and per 

 square meter of body-surface of 1.10 and 40.5 calories, respectively, 

 this being nearly identical with the values for Squad A normal. One 

 month later, November 3-4, similar values were obtained. It thus 

 appears from these measurements that the values found with Squad A 

 were normal, and also that the number of men in the squad was suffi- 

 cient to secure an average value. Jn other words, if Squad A had been 

 twice as large on September 29-30, the heat per square meter and per 

 kilogram per hour would not have altered in the slightest. 



The subsequent course of the basal-metabolism measurements with 

 Squad B is also of interest. On November 17-18 there was a fall of 

 approximately 2 per cent in the metabolism. One month later, 

 December 15-16, there was another fall of not far from 2 per cent. 

 Using the values on October 6-7 as a basis, we have a fall in metaboUsm 

 of about 4 per cent in the heat per kilogram and a httle over 2 per cent 

 in the heat per square meter of body-surface. Up to this point, one 

 might reasonably and legitimately state that there was no seasonal va- 

 riation in metabolism. On the night of January 5-6, prior to the day 

 when the restricted diet was begun with Squad B, a last experiment 

 was made inside the group respiration chamber to obtain the basal 

 value. To our great surprise this showed a very considerable altera- 

 tion in metabolism. The hourly heat per kilogram dropped to 0.98 

 calorie and per square meter of body-surface to 36.8 calories. Using 



