110 



HEMOGLOBIN 



monoxide; so that the equilibrium under consideration was not 



Hb + O2 = HbOg, 

 but Hb + CO = HbCO. 



The latter, however, is supposed to observe the same general laws 

 as the former, though the concentration of carbon monoxide necessary 

 to produce a given percentage saturation of HbCO is of course much 

 lower than that of oxygen necessary to produce the same percentage 

 of oxy haemoglobin. 



The reason for not using oxyhsemoglobin was that the hydrogen- 

 ion concentration of mixtures of oxy- and reduced haemoglobins is, 

 or was at the time when these observations were carried out, beyond 

 the known powers of the platinum electrode. 



In each case the concentration of CO to which haemoglobin was 

 exposed was the same, but the more acid the solution, the lower the 

 percentage saturation with CO. The following table gives (1) the 

 percentage saturation, (2) the acid by addition of which the reaction 

 was adjusted, and (3) the hydrogen-ion concentration resulting. 



Adair (8) has published a set of curves, each of which represents 

 the equilibrium between oxygen and human haemoglobin at a given 

 hydrogen-ion concentration. The hydrogen-ion concentrations vary 

 from 10-8 X -8 {pB. 8-3) to lO-s x 100 {pH 6-0). 



The haemoglobin was dialysed first against water which contained 

 CO2 , so as to detach the sodium from the haemoglobin (this was done 

 with different degrees of thoroughness, accounting for the differing 

 hydrogen-ion concentrations), and the haemoglobin was subsequently 

 dialysed against distilled water to eliminate the carbonic acid. The 

 curves are given in Fig. 34, A similar series of curves was published by 

 Means and myself (9) in 1913, representing the effect of carbonic acid 

 on the dissociation curve of haemoglobin. 



At first sight these curves look rather confused, the fact being 

 that the first few millimetres of COg seemed to alter the degree Of 

 inflection very much; as the hydrogen-ion concentration increased 



