20 



Chapter II 



molecules only, the relation of (1) the oxygen pressure to (2) the per- 

 centage of oxy- to total haemoglobin is capable of being represented 

 as a rectangular hyperbola, the origin of which is at once the point at 

 which there is no pressure of oxygen and no oxyhaemoglobin, and 

 the curve approximates to a line representing complete saturation. 

 If now we turn back to Fig. 7 we shall see that the curve which we 

 have shown as representing the relation of the pressure of oxygen 

 and the percentage of oxyhaemoglobin is identical with the curve we 

 have just given, and therefore the law of mass action is to this extent 

 satisfied. 



Yet this satisfactory result was not reached without a struggle. 

 The ease with which it can be demonstrated at the present time 

 presents a very pleasant contrast to the tiresomeness of the path 



FIG. 10. Shows a series of rectangular hyperbolae, each with A as its origin, 



and approximating to O.Y. 



which had to be trod before the present point of vantage was 

 reached. 



The history of the subject forms an interesting commentary upon 

 the psychology of research. The law of mass action was first quanti- 

 tatively applied to the reaction 



by Hiifner' 1 ', who quite unjustifiably assumed the applicability of 

 the law to the reaction in the form in which we have given it above 

 and obtained a curve very similar to the one which is represented 

 from entirely theoretical considerations. 



