CHAPTER XVI 



THE EFFECT OF TEMPERATURE ON HiEMOGLOBIN 



ixFRiENDof mine once said to me, concerning a certain book, that 

 he liked to give it to his pupils to read because it showed that quite 

 important discoveries could be made as the result of mental processes 

 of a not very high order. I never think of that remark without feeUng 

 a secret hope that he did not know how I came to investigate the 

 effect of temperature on haemoglobin. Of course I know how I 

 should have come to take the matter up, I should have known that 

 oxy haemoglobin was an exothermic compoimd, I should from that 

 have gone on to reason that rise of temperature would have weakened 

 the hnk between haemoglobin and oxygen, I might then from the 

 pubMshed data on the heat of formation of oxyhaemoglobin have en- 

 deavoured to apply Van t' Hoff 's equation and discovered what might 

 be the difference in the equiUbrium constants of the reactions between 

 haemoglobin and oxygen at different temperatures; all this might 

 have involved "mental processes of a not very high order," but it 

 would at least have been a respectable way of approaching the 

 subject. 



The actual avenue was far otherwise. Dr Camis and I were working 

 out an oxygen dissociation curve for which purpose we were equili- 

 brating some haemoglobin in the crude way in which we did things 

 in those days — just corking up some haemoglobin in a glass tube with 

 the necessary atmosphere and shaking the tube in a water bath 

 heated with an ordinary gas flame. Well, on this occasion someone 

 came into the laboratory and interrupted me, so that I left the tube 

 in the bath. I came back to find that the temperature had risen 

 about three or four degrees (Centigrade). The point, when plotted, 

 also to my chagrin, did not fall on the same curve as its fellows. 

 I did it over again, this time keeping the bath at constant tempera- 

 ture, and at the second attempt the point fell into hne. So I discarded 

 the first point for the time being ; but I did put the record of it into 

 a drawer, and on a subsequent occasion I made the definite com- 

 parison of two curves drawn on the same blood but at different 

 temperatures. Comparison of these curves is to be found in the 



