Eespieatory Quotient. 



451 



The respiratory quotients for the 2-hour periods are given with the detailed 

 statistics of the experiments. Unfortunately, but little reliance can be placed 

 on these determinations for short periods save in those instances when the 

 muscular activity of the subject was the same at the beginning and end of the 

 experimental period. As has been pointed out previously, the exact determi- 

 nation of the average temperature of the large volume of air residual inside 

 the chamber (4900 liters) is of the utmost importance to the accurate measure- 

 ment of the oxygen consumption. Under like conditions of muscular activity 

 at the beginning and end of each period, the average temperatures may readily 

 be secured. Experience has shown that even minor differences between the 

 muscular activity at the beginning and at the end of a period result in abnor- 

 mal temperature observations for the residual air and consequently erroneous 

 oxygen determinations and respiratory quotients. On the contrary, since the 

 experimental day ends at 7 a. in. and the subject is quietly resting in bed, the 

 respiratory quotients for 24 hours we believe to be as accurate as can be 

 determined with the type of apparatus used in these experiments. 



The marked acidosis accompanying certain fasting experiments and which 

 we have reason to believe was not absent in some of those here reported, would 

 have an effect upon the respiratory quotient. The conversion of partially 

 oxidized fat into /? oxybutyric acid, for example, would mean a taking up of 

 oxygen unaccompanied by a corresponding liberation of carbon dioxide, and 

 hence the oxygen consumption would be too large and the respiratory quotient 

 too small. The exact effect of this acidosis on the quotient has not been com- 

 puted since the respiratory quotients are not used in this discussion in their 

 ordinary sense. The influence of such an absorption of oxygen unaccompanied 



