HAEMOGLOBIN. 



203 



present in the sample of blood, that is, provided the temperature 

 is the same in the two eases. Of the curves shown in Fig. 27, a 

 represents the degree of dissociation of oxygen from pure oxy- 

 hasmoglobin solution at varying oxygen pressures; ~b, the modifi- 

 cation in the degree of the association produced by the presence 



10 2.0 30 W 50 60 70 90 rO 100 



Fig. 27. 



Ordinates Percentage saturation of haemoglobin with oxygen. 



Abscissae Tension of oxygen in mm. of mercury. 



Curve A Degree of saturation of pure haemoglobin solutions at varying 



pressures. 

 Curve B Modification of degree of saturation caused by presence of salts 



in the blood. 



Curve C Effect of 20 mm. CO pressure on above solution. 

 CUrve D The saturation curve in normal blood at 40 mm. carbon dioxide 



pressure. 



