Oxygenation and Oxidation 



accuracy of ± 0-5 per cent, or equal to that attained in the determina- 

 tion of a single species 6 . 



For the present, we regard as most unequivocal the description of 

 haemoglobin derivatives in terms of their characteristic and at times 

 highly selective absorption spectra (Figure 3). ' Oxyhaemoglobin ' is 

 hence defined by us as the substance capable of yielding established 

 absorption constants at specified wave-lengths, before and after appro- 

 priate chemical treatment. Since oxygen capacity, determined gaso- 

 metrically, may be equivocal, I have taken a step towards the much- 

 needed ultimate standardization of the haemoglobins, based on several 

 independent measurements 31 . For this purpose the oxyhaemoglobin 

 and metmyoglobin of man were originally crystallized 31 » 32 . Sum- 

 marized data upon such crystallized haemoglobins are presented in 

 Table I. They suggest that the spectrophotometry constant for cyan- 



Table I 

 Standardization data on crystallized haemoglobins 51 



* All preparations were crystallized, with the exception of dog myoglobin. 



t Orthophenanthroline method 33 . 



+ €, extinction at depth = 1 cm and concentration — 1 mM per 1 (as in legend to 

 Figure 3). 



§ Value originally based on concentrations determined from O a capacities of 15 dog 

 bloods 29 . Averages of 0-339 and 0-340 per cent for haemoglobin and myoglobin iron 

 (above) correspond respectively to e values for MHbCN, on the iron basis, of 11-37 and 

 11-33. 



II Lyophilized (dried in the frozen state) preparation. 



41 



