226 CARNEGIE INSTITUTION OF WASHINGTON. 



April 22, 1918. The following abstract differs slightly from the original 

 report in that advantage is taken of the final calculations of results to 

 change somewhat the figures therein incorporated. It seems unwise to con- 

 tinue using the old figures, which were given as preliminary data, when the 

 actual results are at hand. 



The report includes a discussion of the influence of the prolonged low diet 

 upon basal metabolism and nitrogen excretion, the neuro-muscular processes 

 and mental condition, and the efficiency during muscular work. Deferring 

 until the appearance of the final detailed report the complete abstracting of 

 the data therein, we may here emphasize the following tentative conclusions: 



With a noiTnal demand, prior to dietetic alterations, of 3,100 net calories, 

 the net calories required for maintenance after the weight had been lowered 

 about 12 per cent by reduced diet averaged about 1,950 calories, or approxi- 

 mately one-third less than the original requirement. One squad of 12 men 

 subsisted for 3 weeks on 1,400 net calories without special disturbance. 



At the end of the reduction in weight the actual heat output during the 

 hours of sleep, as computed by indirect calorimetry, was approximately one- 

 fourth less than normal. The heat output per kilogram of body- weight and 

 per square meter of body-surface was 18 and 22 per cent, respectively, lower 

 than at the beginning of the study. 



Marked losses in total nitrogen were observed. In round numbers the 

 men each lost approximately 150 grams of nitrogen. There is an intimate 

 relationship between this so-called "surplus nitrogen" and the metabolic 

 level. Removing the "surplus nitrogen," we believe, distinctly lowers the 

 stimulus to cellular activity. 



The nitrogen output per day at the maintenance diet of 1,950 net calories 

 was about 10.5 grams. A control group of 12 men, living substantially the 

 same life and eating in the same dining-room, but with unrestricted diet, 

 showed a nitrogen output of 14 grams. 



Pulse-rates as low as 33 were not unusual and daily counts of 32, 31, and 

 30 were obtained; at least one subject gave six definite counts on one morn- 

 ing of 29 per minute. 



The blood-pressure, both systoUc and diastolic, was distinctly lowered. 



The rectal temperature was practically normal. 



No noticeable discomfort was experienced by the subjects, except a feeling 

 of cold. The men continued the usual college activities with no obvious 

 reduction in stamina. 



A second squad, when put for a period of three weeks upon a restricted 

 ration of less than half their previous caloric consumption, showed a reduction 

 in metabolism and a loss in nitrogen in proportionately the same degree as 

 that shown by the first squad. 



Seventeen separate psychological measurements were made with the men, 

 5 by the group method and 12 by the individual method. Typical results 

 are given in table 1, in which the results obtained with normal diet are given 

 in bold-face type. The experiment lasted 4 months, September 29, 1917, 

 to February 3, 1918. From this table it will be seen that the accuracy in 

 tracing gradually improved. With the control squad (see results under C. S.) 

 it continued to improve on low diet, with no definite effect established. The 

 same may be said with regard to addition. 



With the strength of grip the results obtained with the diet squad (D. S.) 

 were definitely below those for the control squad, but on the three reduction 

 dates for the latter squad there was no definite change. Therefore the differ- 

 ence in level between the two squads can not be interpreted as due entirely 

 to the low diet. The eye movements show a progressive reduction in speed 



