Metabolism Experiment Xo. 101. 21 



in the respired air plus the 5.6 grams excreted in the urine, making a total 

 of 184.4 grams. Assuming that the total carbon from the protein disintegrated 

 is excreted and that 52.8 per cent of the protein is carbon, the disintegration 

 of 38.7 grams of protein would correspond to the excretion of 20.4 grams of 

 carbon. Obviously, a portion of this carbon is excreted as unburned carbon 

 in the urine and a portion of it as carbon of carbon dioxide exhaled ; but since 

 the unoxidized portion of the urine is taken into consideration in the output, 

 it is proper that the 20.4 grams of carbon from protein should be assumed as 

 being entirely excreted. Since the total carbon elimination is 184.4 grains 

 and but 20.4 grams were derived from protein, there obviously remain 1G4 

 grams to be apportioned between the katabolism of fat and of carbohydrate 

 from food and body material. 



The relatively small amount of carbohydrates ingested in these experiments 

 leads to the perfectly proper assumption that it was entirely absorbed during 

 the course of 24 hours, and from table 4 it can be seen that there were 238.7 

 grams of carbohydrates. Of this amount, it is assumed that 21 grams were 

 deposited as glycogen in the body. Leaving out of discussion the slight differ- 

 ences in the carbon content of food carbohydrate and glycogen, we may con- 

 clude that the total amount of carbohydrate katabolized was 



238.7 21.0 = 217.7 grams. 



This corresponds to 91.5 grams of carbon. 1 This carbon, together with the 

 carbon from protein, amounts to 



91.5 -f 20.4 = 111.9 grams 



and hence there remain from the total excretion of 184.4 grams, 72.5 grams of 

 carbon which are derived from fat either of food or of body. Waiving the 

 question of difference between the percentage of carbon in food-fat and that 

 in body-fat, and assuming the percentage of carbon in the butter-fat for the 

 most part present in the diet of this experiment to be 75 per cent, 72.5 grams 

 of carbon are equivalent to 96.7 grams of fat. The calculation of the total 

 fat in the food shows that there were 33.2 grams, which, deducted from 96.7 

 grams, leave 63.5 grams of fat katabolized from body-material. 



Balance of Intake and Output of Nutrients. 



The gain or loss of material is shown in table 8 in which the amounts of 

 material katabolized are those calculated as indicated above. 



According to the calculations as presented in table 8, there was a gain to 

 the body of 1.17 grams of protein, a loss of 63.5 grams of fat, and a gain of 

 21 grams of carbohydrate. In considering these values as thus presented it is 

 important to note in the first place that no allowance whatever is made for 

 the material in feces. While the earlier idea that the feces consisted in large 



1 Since fully 60 to 70 per cent of the carbohydrates ingested were in the form of 

 mono- or di-saccharids rather than starch, it has seemed reasonable to assume that 

 there would be on the average 42 per cent of carbon. 



