28 



Metabolism of Healthy Man. 



Table 12. Elements and materials katabolized in body, Apr. 11-18, 1903, 7 a. m. to 



7 a. m. Metabolism experiment No. 102. 



Nitrogen . 

 Carbon 

 Hydrogen , 

 Oxygen 



Grams. 



10.8 

 224.3 



97.8 

 658.8 



Water 1 



Protein 



Fat 



Carbohydrates. 



Grams. 



683.8 



64.8 



117.8 



226.3 



1 Water of urine not included. 



An interesting comparison of the energy derived from katabolized body- 

 material with the total heat production shows a most satisfactory agreement 

 between the direct and the indirect calorimetry. (See table 13.) 



Table 13. Comparison of energy as computed from body-material katabolized with 



heat production as measured, Apr. 17-1S, 1903, 7 a. m. to 7 a. m. 



Metabolism experiment No. 102. 



(a) 

 (b) 

 (c) 

 (d) 



(6) 



(/) 

 (fir) 



Energy of body protein katabolized 



Potential energy of urine 



Net energy {a b) 



Energy of body fat katabolized 



Energy of body glycogen katabolized 



Total energy computed from katabolized material (c+d+e) 



Total heat production as measured 



Heat production computed greater than heat production measured : 

 ih) Amount (/fir) 



(i) Proportion (hs-g). 



Cals. 



366 



90 



276 



1124 



948 



2348 



2334 



+14 

 Per cent. 

 +0.6 



Material absorbed from, food. Having considered the katabolism of this 

 subject, it is now proper to inquire as to how far the diet ingested during this 

 experiment sufficed for maintenance. From the assumed composition of food 

 materials eaten, the amounts of protein, fats, and carbohydrates absorbed from 

 the food and the energy of each have been calculated and placed in table 14. 

 In these calculations it has been necessary to assume the percentage com- 

 position of food material. This has been done after reference to the average 

 of a large number of analyses of food materials of a like nature previously 

 used in this laboratory. Furthermore, in the absence of a satisfactory separa- 

 tion of feces, it is necessary to assume the coefficients of digestibility for the 

 different nutrients. It is seen from the figures presented in the table that 

 the energy supplied by the food is 1859 calories. 



Table 14. Amounts of protein, fat, and glycogen absorbed 1 from food, 



and energy of each, 2 Apr. 17-18. 7 a. m. to 7 a. m. 



Metabolism experiment No. 102. 



Material. 



Protein ... 

 Fat 



Glycogen 



Total.. 



Amount. 



Grams. 



79.2 



59.6 



201.0 



Energy. 



Calories. 

 448 

 569 



842 



1859 



1 Assuming as coefficients of digestibility for protein, 90.5 per cent ; for fat, 95.2 per cent ; for 

 carbohydrates, 97.5 per cent. (United States Department of Agriculture, Office of Exp. Stas. 

 Bui. 175, p. 130.) The results are in terms of body-material. 



2 Factors for hpat of combustion per gram of protein, 5.65 calories ; of fat, 9.54 calories ; of 

 glycogen, 4.19 calories. 



