i8o 



A RESPIRATION CALORIMETER. 



of the urine, and consequently the analyses are not made on periods 

 shorter than 24 hours, save in the case of determinations of total nitrogen, 

 which are at times made on 6-hour periods. 



STATISTICS OF FOOD, FECES, AND URINE. 



In Table 5 the percentage composition of the food materials, feces, 

 and urine are given. 



TABLE 5. Percentage Composition of Food Materials, Feces, and Urine, 

 Metabolism Experiment No. 70. 



These values are determined directly in the case of water, fat, ash, 

 nitrogen, carbon, and hydrogen. The protein is obtained from the 

 nitrogen by multiplying by the factor 6.25. The carbohydrates are 

 determined by difference. The heat of combustion per gram is deter- 

 mined by combustion in the bomb calorimeter. 



In all cases except that of the feces the materials are analyzed on 

 the fresh basis, i. c., original weights are on the fresh material. The 

 feces of necessity are analyzed after drying. 



The total amounts of food, with the quantities of nutrients and energy 

 supplied, are shown in Table 6. 



TABLE 6. Weight, Composition, and Heat of Combustion of Food, Metabolism 



Experiment No. jo. 



For purposes of further computation the amount of oxygen in the 

 water-free substance of the food is here given, though obviously this 

 is a result of indirect determination. 



