280 THE INCOME OF ENERGY 



excretion of nitrogen has been found to be fairly 

 uniform, place the subject upon a simple diet 

 of eggs, bread, milk, and butter, containing as 

 much nitrogen as he excretes. 1 



The diet may be chosen from the following 

 table. 2 



The relative proportion of proteid, fat, and car- 

 bohydrate per day should be about as follows : 



Proteid 100 grams 



Fat ...... 100 grams 



Carbohydrate . . . 250 grams 



450 grams 



Kepeat the determination of urea in the urine 

 during four more days. 3 Calculate the nitrogen 



1 Owing to the variation in the nitrogen content of meats, 

 they should be omitted. 



Physiological heat values : 



1 gram proteid = 4000 small calories 



1 " fat =9423 " 



1 " carbohydrate = 4182 " " 



Proteids contain about 16 per cent nitrogen. Hence to obtain 

 the amount of metabolized proteid from the nitrogen in the 

 urine multiply the latter by 6.25. 

 In one pound there are 453.6 grams. 



2 Coffee and tea contain so little nitrogen that they may be 

 added to the diet in small amounts to suit the individual taste. 



8 The twenty-four hours should begin in the morning im- 

 mediately after passing the urine excreted during the night. 



