THE NATURE OF HEMOGLOBIN SOLUTION 77 



Hufner(5), and the question like some others was "settled" by him. 

 His observations, made in collaboration with Gansser, showed that 

 a so-called solution of haemoglobin exerted an osmotic pressure which 

 corresponded to a molecular weight for the substance of about 

 17,000. This highly satisfactory result left no doubt in the minds 

 of the authors that haemoglobin existed in true solution and that 

 the molecule was the simplest possible, i.e. one which contained a 

 single atom of iron. On this basis a 1 per cent, solution of haemo- 

 globin would have an osmotic pressure of about 10 mm. of mercury, 

 which was about what Hiifner and Gansser found it to be. 



Reid(6) previously had made similar measurements. Exactly why 

 his results were called in question by Hiifner I have never quite 

 known. Of course they appeared somewhat anomalous but they 

 showed a healthy scepticism — a scepticism which in Reid I have 

 always admired since I heard the following story about him — which 

 story may of course be apocryphal. Reid read a research which had 

 to do with diffusion or vitalism or something of the kind. Armed with 

 a soda-water bottle and two frogs Reid pursued the writer round 

 the European capital in which his laboratory was situated in ojder 

 that the author of the work might have the opportunity of demon- 

 strating the phenomenon which he had described, but as I heard 

 it the author always had a train to catch or some equally urgent call 

 afoot. That, however, is a digression, I only wish to indicate that 

 such a combination of enthusiasm and energy cannot in the long 

 run go unrewarded. Certainly in the matter of haemoglobin's osmotic 

 properties Waymouth Reid entirely got the better of Hiifner. As the 

 result of a most careful piece of work which is less quoted than it 

 should be, Reid concluded that the osmotic pressure of haemoglobin 

 was but a third of what Hiifner and Gansser made it out to be. Reid 

 obtained very uniform and consistent results. 



It is just at this point of consistency that the problem took the 

 next turn, for Roaf (7), who worked at the subject in Liverpool, made 

 an important advance in pointing out that the osmotic pressure of 

 haemoglobin could not be regarded as a constant quantity, but that 

 it varied with the nature of the solvent of the haemoglobin, whether 

 for instance it was acid, alkaline, etc. Among Roaf's results was the 

 apparent anomaly that the osmotic pressure settled down on occa- 

 sions to something which corresponded to less than one molecular 

 weight. 



Roaf, I remember, very kindly showed me his osmometers and 



