36 



Chapter III 



agrees with all we have as yet considered with regard to haemo- 

 globin. 



We are now in a position, from the values of K which we have 

 determined above, and from the knowledge that dialysed haemoglobin 

 exists in single molecules, to calculate the percentage saturation of 

 haemoglobin with oxygen at any oxygen pressure and at any tem- 

 perature. Below we give a diagram of the dissociation curves of 

 oxyhaemoglobin at the temperatures 16, 25, 32, 38 and 49 C. 



100 



10 



80 



90 



100 



FIG. 17. Dissociation curves I, II, III, IV and V correspond to 16, 25, 32, 38 and 49 C. 

 respectively. Oxygen pressure plotted horizontally, percentage of reduced haemo- 

 globin vertically downwards. 



In order to arrive at some sort of knowledge, as to how fast the 

 forward and backward reactions of the oxidation and reduction of 

 haemoglobin go on, and as to how far these rates are affected by 

 temperature, some further experiments were done by Barcroft and 



