400 



THE RESPIRATION 



0, the same as that which obtains in alveolar air namely, about 95-100 

 mm. Hg; and to obtain the rate of reduction pure N 2 or H 2 gas is bub- 

 bled through. 



10 2O 30 40 50 60 70 80 SO 10o QiidatiOD 



17-5 C. no COo 



Induction 



100f 



Oxidation 



37-5 C. no C0 2 



Keduction 



Fig. 141. Curves showing relative rates of oxidation and reduction of blood as influenced by 

 temperature and tension of COo. 

 Ordinates Percentage saturation. 

 Abscissae. Time in minutes. 

 Reducing gas, hydrogen. 

 Oxidizing gas, oxygen. 



A, temperature 17.5 C., with no CO 2 . 



B, temperature 37.5 C., with no CO 2 . 



C, temperature 37.5 C., but the On and H contained 40 mm. Hg pressure of COa. (From 

 Joseph Barcroft.) 



The rates of reduction or of oxidation as thus determined are then 

 plotted in curves constructed with the percentage saturation of the 

 hemoglobin on the ordinates and the time in minutes along the abscissa? 

 (Fig. 141). Even if we use blood in this experiment and therefore make 



