686 EXPERIMENT STATION RECORD. 



and at the same time provide a diet adequate in bulk and energy it was found con- 

 venient to materially diminish the amount of animal food, though the author 

 explicitly stales that it was not his object to provide a vegetarian diet. 



Throughout the investigation careful records were kept of the foods consumed, and 

 at intervals the balance of income and outgo of nitrogen was ascertained, the neces- 

 sary analyses being made. In the case of urine the specific gravity, uric acid, and 

 phosphoric acid were also determined. Apparently the energy value of the foods 

 was calculated. In the case of the soldiers and athletes careful records were kept of 

 the physiological condition of the men. A study of the reaction-time and other 

 psychological data was also carried on with the students, and in connection with the 

 investigation morphological studies of the blood were also made. 



The author was himself the subject of the first of the investigations reported. 

 When the change of diet was made the body weight diminished somewhat, then 

 became fairly constant, and for 9 months the author found that he was able to main- 

 tain a body weight of 57 kg. with a diet furnishing in round numbers 40 gm. of pro- 

 tein (6.4 gm. nitrogen) and 2,000 calories of energy per day. He states that his gen- 

 eral health and well-being were normal or above. Similar results were obtained 

 with 4 other professional men. 



Considering the group of professional men as a whole, the author believes that the 

 so-called "minimal proteid requirement of the healthy man — which for this group 

 of individuals w r e may place at the low level of 0.093 to 0.130 gm. of nitrogen per 

 kilo of body weight— represents the real physiological needs of the system for nitro- 

 gen, and in so far as our present data show, anything beyond this quantity may be 

 considered as an excess over and above what is required for the actual physiological 

 necessities of the body. Naturally, however, there may be nothing detrimental in a 

 slight excess of proteid beyond the daily needs." 



The studies with soldiers were carried on with 13 men, especially detailed for the 

 purpose, and extended from October to April. The men were busily engaged with 

 gymnasium work, military drill, and some routine duties connected with the experi- 

 ments. Soon after the change in ration the body weight became fairly constant, on 

 an average, and no great difficulty was experienced, according to the author, in 

 maintaining a condition of nitrogen equilibrium. The men were able to adjust them- 

 selves to the lower protein ration, and lived for 5 consecutive months "with a proteid 

 metabolism corresponding to 7 to 8 gm. of nitrogen per day, with maintenance of 

 body weight and without discomfort or loss of bodily vigor. " The corresponding 

 energy value of the diet was placed at 2,500 to 2,600 calories. 



A similar investigation extending over 5 months was made with 8 university students 

 trained in athletics. "As the results show, all these men reduced their rate of proteid 

 metabolism in such degree that the amount of nitrogen excreted daily during the 

 period of the experiment averaged 8.8 gm., implying a metabolism of about 55 gm. of 

 proteid matter per day. In other words, these athletes were able to reduce their nitro- 

 genous metabolism to as low a level as many of the men of the professional group and of 

 the soldier group, and this with not only maintenance of health and strength, but with 

 a decided increase in their muscular power. Metabolized nitrogen per kilo of body 

 weight for all these men, with one exception, during the experiment amounted to 

 0.108 to 0.134 gm. per day, fully as low as was obtained with the members of the 

 soldier detail on their prescribed diet. It is clear, therefore, that physiological 

 economy in nutrition is as safe for men in athletics as for men not accustomed to 

 vigorous exercise." The energy value of the daily diet was on an average not far 

 from 2,500 calories. 



One of the interesting points discussed by the author has to do with the bodily 

 output of uric acid. From the investigations as a whole it appeared that "we can 

 greatly diminish the output of uric acid by simply restricting the extent of proteid 

 katabolism, through reduction in the amount of proteid food." 



