PSYCHOLOGICAL MEASUREMENTS. 555 



mentally, as the men came to the Nutrition Laboratory immediately 

 from their Christmas vacations. Starting with January 8, the diet of 

 each man in Squad B was reduced to 1,375 net calories per day, and the 

 men had had a total of this amount in the three meals preceding all 

 evening psychological sessions.^ 



Except for one session, December 19, Squad A served on Saturdays, 

 usually at intervals of two weeks. December 19 (Wednesday) was just 

 before the Christmas vacation and the men left for their homes on 

 December 20, inmiediately after the morning measurements, which 

 in this case were electrocardiograms. Experiments on January 26 and 

 February 2 were separated by only one week. 



In comparing the neuro-muscular results for the different dates, par- 

 ticularly with Squad A, it will be of interest to correlate these with the 

 values for net available energy per man during these same periods. 

 The average net energy levels are discussed elsewhere (p. 270), and 

 shown in the body-weight charts. Conceivably the amount of food 

 taken on the same day when the men served in the psychological 

 experiments of the evening would be of more immediate influence on 

 the comfort and mental attitude of the men and so on these psycholog- 

 ical results than the net energy figure for the days preceding this one. 

 In arranging the experiment it was the plan to provide uniform con- 

 ditions for the psychological tests. The evening meal which preceded 

 these tests was kept standard at very nearly 700 calories for both squads 

 and on all dates, including normal and low-diet experiments. Usually 

 the noon meal was also standard, as the men very frequently came to 

 Boston in the morning. The breakfast at the Nutrition Laboratory 

 which preceded the morning tests was likewise standardized at about 

 640 calories for both squads on all dates. Thus the energy intake in 

 the meal or two immediately before all the psychological sessions was 

 uniform and at an average low level. The breakfasts in Springfield 

 changed considerably in accordance with the fluctuations in the weight 

 of the subjects, as it was the custom in the investigation to adjust the 

 food to weight mostly in this meal. The data (see table 146) for the net 

 available calories per man on those days when the members of Squad A 

 came to Boston and had evening psychological measurements show 

 for any subject considerable variations from date to date which are 

 largely the differences in breakfasts. The individual averages for 

 October 13 to February 2, inclusive — i. e., for all but September 29 — 

 are given at the bottom of the table; below this are found the averages 

 for net available calories throughout the whole low-diet experiment, 

 exclusive of the Thanksgiving and Christmas vacations. These latter 

 individual averages for the experiment are in every case larger than 



* For details of the standard meals given in Boston, see tables 25, 26, and 27, pp. 262 and 263. 

 On dates previous to January 8, members of Squad B were eating uncontrolled and 

 supposedly had about 3,800 net calories per day per man. 



