Aggregation theory 



69 



Perhaps the most telling feature of the aggregation theory is its 

 adequacy to meet these unexpected and peculiar requirements. 



At first sight it wholly failed to do so. If two assumptions be 

 made, the matter, as Hill has shown (8) , becomes quite clear. Of 

 these one has already been made : it is the instability of unsaturated 



, . affinity for CO . 

 compounds ; the other is that the ratio ffi .; ^ ^ is even greater 



in the case of the half-saturated than in the case of the completely 

 unsaturated compounds. With regard to the first assumption it 

 may be said that (1) no unsaturated oxide has ever been isolated 



100 

 90 

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 70 

 60 

 50 

 40 

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 20 

 10 



\ 





10 



12 



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18 



20 



FIG. 36. Heavy line represents dissociation curve representing partition of haemoglobin 

 between 2 and CO at 38 C. CO pressure = 0-00854 / of an atmosphere throughout. 

 Light line represents the corresponding hyperbola. 



(2) there is no transitional spectrum between that of oxy- and of 

 reduced haemoglobin. 



It remains only to state the numerical relation between K and 

 the carbonic acid pressure. It will not surprise the reader to hear 

 that this relation is similar in the cases of CO-haemoglobin and 

 oxyhaeinoglobin. The two fall on the same curve, the difference 

 lying only in the scale on which the curve is plotted. The temptation 

 to speculate on the form of this curve is considerable, but till a greater 

 number of points are forthcoming the temptation must be repressed. 

 It must suffice to say that it is not a parabola the curve which 



