184 



A RESPIRATION CALORIMETER. 



The quantity of oxygen in the air of the chamber at the beginning 

 and end of each day is learned by analysis of samples of the air taken 

 at 7 a. m., and is given in column (a). Similar values for the different 

 experimental periods, given in the same column, are found by calcula- 

 tion, as explained on page 95. 



The quantities in column (^) represent the increase or decrease in the 

 oxygen content of the air during the different periods. These are 

 expressed by volume in column (6) and by weight in column (c). The 

 algebraic difference between the quantities in columns (af ) and (V) is the 

 amount consumed by the subject. 



TABLE 10. Record of Oxygen in Ventilating Air Current and Respiratory 

 Quotients by Periods, Metabolism Experiment No. 70. 



RESPIRATORY QUOTIENT. 



The ratio between the volume of carbon dioxide exhaled and the 

 volume of the oxygen inspired, and indicating in marked degree the 

 nature of the materials burned inside the body, is commonly called the 

 respiratory quotient. In the experiments with men, it is computed on 

 the sheets upon which are recorded the data for the determinations of 

 the amount of oxygen consumed, Table 10, and is recorded in column 

 (^). In determining the respiratory quotient, the weight of carbon 

 dioxide found is converted to liters by multiplying by the factor 0.5091 , 

 column (tf) , Table 9, while the weight of oxygen absorbed by the bodj' 

 is converted to liters by multiplying by 0.7, column (/) of Table 10. 

 The ratio between the volumes of carbon dioxide eliminated and oxygen 

 absorbed, CO 2 -v- O 2 , represents the so-called " respiratory quotient." 



