READJUSTMENTS OF REGULATION 33 



FIG. 2. Lower curve absorption of CO2 by blood in pres- 

 ence of air and CO2. Upper curve absorption of COs 

 by blood in presence of hydrogen and COa. The line 

 A-B represents the absorption of CO2 within the body. 



therefore represented by the thick line starting at 40 

 mm. which is the pressure of CO 2 in arterial blood. 

 This line rises steeply, so that far more CO 2 can be 

 taken up by the blood with a given rise of CO 2 pres- 

 sure than would be the case if oxyhaemoglobin and 

 reduced haemoglobin had the same effect on the ab- 

 sorption of CO 2 . It follows also that when the venous 

 blood reaches the lungs and suddenly becomes oxy- 

 genated, the pressure of CO 2 in the blood suddenly 

 rises. In this way much more CO 2 is given off than 

 would otherwise be the case considering the existing 



