INCOME AND OUTGO 335 



remainder, 211 grams, stands for carbon from carbo- 

 hydrate and fat. 



One would say that we had now come face to face 

 with a hopeless difficulty. How can we assign to each 

 of the two types of non-nitrogenous fuel the proper share 

 of the carbon? There is nothing individual about their 

 end-products. The division of the carbon into these 

 portions is, in fact, too difficult to explain in detail. 

 But the means of guidance is furnished by the oxygen 

 consumption. The amount necessary to oxidize a 

 gram of fat is different from that needed to oxidize a 

 gram of sugar. When a certain quantity of oxygen is 

 known to have been used to release a certain quantity 

 of carbon dioxid the expert in nutrition has no trouble 

 in solving equations that show how much fat and how 

 much sugar have been used. 



Let us suppose that in our hypothetic example the 

 211 grams of carbon from non-protein sources is found 

 to represent 91 grams of fat and 350 grams of carbo- 

 hydrate. (These are possible figures.) We can go 

 on to say that 91 grams of fat should have given rise 

 in its decomposition to about 845 Calories, while 350 

 grams of carbohydrate should have yielded about 

 1400 Calories. Adding: 



Calories from protein 300 



Calories from fat 845 



Calories from carbohydrate 1400 



Total 2545 



When a man is in a calorimeter which is also a respira- 

 tion chamber we have the interesting possibility of 

 comparing the heat which he actually produces with 

 that which he should theoretically evolve direct with 

 indirect calorimetry. 



The figures obtained are in close agreement. This 

 means that the living organism produces no measurable 

 energy which cannot be accounted for as derived from 



