194 



REPORTS ON INVESTIGATIONS AND PROJECTS. 



Table I. — Average Normal Output of Carbon Dioxide and Heat from the Body. 



The method of making a rough calculation of the average daily output of 

 the heat from a man is given in table 2. 



Table 2. — Average Daily Output of Heat of a Man at Light Muscular Work. 



Daily program. 



At rest, sleeping, 8 hours, 65 calories per hour 



At rest, awake, sitting up, 6 hours, 100 calories per hour 

 Light muscular exercise, 10 hours, 170 calories per hour 



Total output of heat, 24 hours 



Heat 

 output. 



cals. 

 520 

 600 



1,700 



2,820 



Since muscular work plays such an important role in gross metabolism, it 

 is of interest to see to what extent mental work affects metabolism, and a 

 brief resume of previously published experiments in which students wrote 

 their college examinations while inside the respiration chamber is given in 

 this paper. No effect of mental work on metabolism was noticeable.* 



After considering the results of excessive muscular work,* the conclusion 

 is drawn that in general if the appetite is ordinarily followed it will result in 

 a most perfect adjustment of the food intake and the food requirement. 

 Obviously it is important to select foods that agree with a person ; excessive 

 amounts of sweets and foods difficult of digestion are certainly to be avoided, 

 but whether the no-breakfast, no-dinner, or no-supper plan be followed, it is 

 absolutely certain that in the course of 24 hours, or perhaps in the course of 

 a week, the amount lost in the meals voluntarily given up will be compen- 

 sated by the increased consumption at other meals. 



* See Year Book, Carnegie Institution of Washington, 1908, p. 190. 



