44 



HEMOGLOBIN 



span changed, as indeed it has been known to do, without any treat- 

 ment (Mrs Kerridge) . 



Reasons will be given later in this chapter for the supposition that 

 the alteration in the span is due to alteration in the globin ; they may 

 not be very strong ones, but, if true, surely a remarkable pheno- 

 menon confronts us. Why, and how, should the globin of a rabbit's 

 haemoglobin alter on haemorrhage? Many answers might be given 

 but they would be mere speculations. Other questions arise, how- 

 ever, which loom distant and large through mists of uncertainty: 

 Is globin merely a sample? Do all the proteins in the body change? 



Fig. 8. 



mm H5-* 



, Oxygen dissociation curves of haemoglobins of various forms of life 

 at different temperatures. 



Let us leave that field for one in which the facts are more concrete. 

 We come to the specificity of haemoglobin in respect to its affinity 

 for gases. The first workers to draw attention to this phase of the 

 problem were Douglas, Haldane and Haldane(iO). In 1912 they 

 showed that if a solution of haemoglobin made by diluting blood one 

 hundred times with distilled water were exposed to -093 per cent. CO 

 in air, the haemoglobin became 67 per cent., or 49 per cent, saturated, 

 according as it was human blood or that of a mouse. No 

 further observation was made on the subject until the oxygen 



