40 Chapter III 



Hill and I therefore performed another experiment from this 

 point of view, i.e. to see whether the actual points determined 

 followed a curve prescribed by the laws of mass action. We varied 

 the conditions by making- the haemoglobin in a different way, making 

 the rate of reduction much slower and determining six points instead 

 of four. The result worked out as follows : 



Temperature 38 C. 



Points A B C D E F 



Time from beginning of Exp 14-5 32 55 80 114 mins. 



Percentage saturation observed ... 92'5 83 71 64 55 46 



Ditto calculated 92-5 82 72-5 63 51-5 46 



The correspondence of the determined points with the theoretical 

 values is equally complete under these altered circumstances. 



There seems to be scarcely any limit to the possibilities which 

 haemoglobin offers to the student of colloids : a colloid with a simple 

 chemical reaction which can be treated quantitatively with little 

 difficulty is of very rare occurrence. There is little doubt, if haemo- 

 globin could be made and kept with ease, that it would be a medium 

 for an enormous volume of illuminating work. 



REFERENCES 



(1) Nernst, Theoretical Chemistry. 



(2) Barcroft and Hill, Journal of Physiology, xxxrx, p. 411. 



(3) Hiifner and Gansser, Archie f. Anat. und Physiol. p. 209, 1907. 



(4) Weymouth Reid, Journal of Physiology, xxxm, p. 12, 1905-6. 



(5) Roaf, Proc. Physiol Soc. p. 1, 1909. 



