98 



HEMOGLOBIN 



alluded to in another place. The whole question took on a new aspect 

 when it became clear, as will appear hereafter, that the affinity of 

 haemoglobin for oxygen is profoundly influenced by the nature of 

 electrolytes (3) in the solution. 



S X 



10 20 30 40 50 60 70 80 90 100 



Fig. 27. Ordinates = percentage saturation of haemoglobin with oxygen. Abscissae 

 = tension of oxygen in mm. of mercury. Curve I = rectangular hyperbola. 

 XY = 800. Curve II = Bohr's dissociation curve of haemoglobin. 



® Points determined from dialysed solution. 



D Points determined from undialysed solution. 



The bearing of this discovery was at once grasped by Ff . Roberts (4), 

 who suggested making a solution after the method of Bohr* and 

 then dialysing a portion of the solution to get rid of such residual 

 salts and traces of ether as might be in it ; finally comparing the dis- 

 sociation curves obtained from the dialysed and undialysed portions. 



^ I.e. precipitating the crystals with ether from centrifugalised corpuscles, wash- 

 ing them, redissolving them and shaking out the ether. 



