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A TEXTBOOK OF PHYSIOLOGY 



genous bodies, the total nitrogen excreted in the urine, and multiplying 

 this by 6-25 the average ratio of nitrogen (16 per cent.) to the total 

 weight of protein (*= 6-25). 



* The first is bomb value; the second is value for body after subtracting value for 

 urea formed, etc. 



Note that column 2 is kilogramme-calories, the other columns gramme-calories. 



Let us suppose, for example, that the diet is calculated to contain 

 (dry weight) 125 grammes of protein, 500 grammes of carbohydrate, 

 and 50 grammes of fat. 



From the chemical composition of each of these foodstuffs the 

 amount of carton and nitrogen is calculated 



Protein 

 Carbohydrate 

 Fat . 



Carbon 

 (Grammes). 



62 



200 



38 



Nitrogen 

 (Grammes). 

 20 



Total 300 2<> 



The energy value of such a diet in terms of heat is * 



Protein 



Carbohydrate 



Fat 



Caloric*. 

 125x4-1= 512-5 



50x9-3= 



3027-5 



The Output. Since protein is the only body in the above diet 

 which contains nitrogen and sulphur, the amount of protein katab- 

 olism of the body can be arrived at by estimating carefully the amount 

 of nitrogen or sulphur combined in the excreta. The nitrogen is most 



* For the food digested and utilized the values can be taken as protein 4, fat 9,. 

 carbohydrate 4. 



