30 LIBERATION OF ENERGY 



2(C5iH980e) + I45O2 = IO2CO2 + 98H2O. 



Vol COo 102 



Now ratio = ^j ^ r>." = ttt. = 0-70. 

 Vol O2 145 



That is, ratio for carbohydrates is 1. 



„ ,, fats ,, 0-7 (circa) 



(Zuntz gives 0-707 as an average figure for fats.) 



(VII) Values for a non-protein ratio lying between 0-7 and 1 

 denote the utilisation by the body of a mixture of fats and carbo- 

 hydrates ; the closer the ratio comes to unity the more carbo- 

 hydrates are being oxidised, and vice versa. 



(VIII) Knowing the proportion of carbohydrate and fat in the 

 diet, one may calculate the amount of energy set free from the 

 two following figures : 



(«) If carbohydrate alone is used each litre of O2 = 5-047 Cals. 

 (6) If fat „ „ „ „ „ = 4-686 Cals. 



Intermediate values may be obtained by interpolation. 



(IX) The results obtained by indirect calorimetry are within 

 2 per cent, of results from the respiration calorimeter. In a series 

 of twenty-two different experiments with a dog, Murlin and Lusk 

 obtained the following results : 



Indirect calorimetrv . . 2,244 Cals. 



Direct 2,230 „ 



Difference . . . 14 ., 



Percentage . . . 0-6 ., 



(X) If the ratio is greater than 1, say, 1-5, it shows that for every 

 three volumes of CO2 evolved, only two volumes of oxygen are being 

 taken from the air. This type of result is obtained either during 

 severe exercise when an oxygen debt is being built up, or in a 

 hibernating animal just before it begins its winter sleep, i.e. when 

 fat is being formed from carbohydrate. 



Further Reading 



Crockeh and Matthews. " Theoretical and Experimental Physical 



Chemistry." J. k A. Churchill. 



