294 



MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Table V. — Record of work done — Metabolism i xpi rimeni No. 12 — Continued. 



Date and time. 



Cyclometer 

 reading.* 



Apr. 15, 8.20 a. m . 

 15, 10.20 a. m 



15, 12.30 p. in 

 15, 3.50 p. m . 

 15,5.30 p. in . 



168 



132 

 93 



Number of 

 miles. 



* 



36 

 39 

 36 

 23 



34 



Actual 

 duration of 



work. 



Mins. 

 120 

 120 

 120 

 120 



600 



1,920 



Heat 

 equivalent. 



Watts. 



30 



Calories, 



103.7 



26 89.3 



801. 



"The cyclometer was reversed. 



Food and excreta. — The weight, composition, and heat of combustion of the food and feces in 

 this experiment are shown in Tables VI and VII. The weights of the different elements and 

 compounds are computed by use of the values for percentage composition of the different materials 

 as shown in Tables I and II: 



Table VI. — Weight, composition, and heat of combustion of foods — Metabolism experiment No. 12. 



Table VII. — Weight, composition, and heat of combustion of feces — Metabolism experiment No. U. 



The separations between the feces from the food consumed during the experiment and 

 those from the food consumed before and after were made by means of charcoal, as described on 

 page 239. Inasmuch as separations made in this way are at the best not as satisfactory as might 

 be desired, no attempt was made to determine the excreta from the food on different days of 

 the experiment. It is assumed that, when the food and exercise are so nearly uniform, the 

 undigested residues and metabolic products would not vary a great deal from day to day. Even 

 if there were irregularities from day to day they would hardly be large enough to affect very 

 greatly the average for the whole experiment. 



The amount, specific gravity, and nitrogen of the urine for the different 6-hour periods 

 during the experiment are shown in Table VIII. and the carbon, hydrogen, water, and energy of 



