2 HEMOGLOBIN 



of many forms of life (7). Of these one of the most fruitful was the 

 comparison between the haemoglobin in the larva of the fly Gastro- 

 philiLS and that of the horse (7), (8), the point of the comparison being 

 that the Oastrophilus larva grows in the equine stomach. But though 

 the larval haemoglobin is manufactured in the horse it is not the 

 same spectroscopically as the horse's haemoglobin. Moreover it is not 

 evident why the Oastro'philus larva should contain haemoglobin at 

 all. The primary use of haemoglobin in the Mammalia is for oxygen 

 transport. In Oastrophilits larva the haemoglobin is fixed and the 

 same is true of the haemoglobin in mammalian muscles and many 

 other places. Keilin therefore was led into an investigation of the 

 structure and function of haemoglobin in muscle — this research led 

 to his discovery of cytochrome (8), a body closely related to haemo- 

 globin, which is very widely distributed throughout the animal and 

 vegetable kingdoms — so much so as to challenge the question whether 

 it or its constituents are not really more primitive than chlorophyll. 



What is the nature of the differences between one haemoglobin 

 and another? 



Clearly there is the possibility that as between two different 

 samples of haemoglobin, the haematin may be uniform and the globin 

 may differ. Or the globin may be the same and the haematin may 

 differ. Or both the globins and the haematins may differ. . 



One method of attacking the question was to treat the haemoglobin 

 with alkah in the presence of a reducing agent. The idea — erroneous 

 as it turned out — was that the globin would be split from the haematin 

 and the resulting spectrum would be that of reduced haematin in 

 alkaline solution. In this task Anson and Mirsky(9) repeated (though 

 quite independently) an observation which had appeared sporadically 

 in the previous literature but the importance of which had never 

 been appreciated (Bertin-Sans and Moitessier(io), and Dilling(ii)), 

 namely, that haemochromogen is not reduced haematin in alkaUne 

 solution, but is a compoimd of that body with globin. Anson and 

 Mirsky (9), working over a number of mammalian bloods, found that 

 the spectra of the haemochromogens which they yielded were identical. 

 From this it may be gathered that in this range of haemoglobins 

 the haematin portion is identical in all, and that the globins are 

 different. 



The question arises then : If the globins are different in the haemo- 

 globins of the horse and the mouse, why have the haemochromogens 

 identical spectra? That question leads to another: What is the 



