62 ANIMAL COLOUEING MATTERS. 



observation ?* I am quite aware of tlie near relationsMp of these 

 pigments to haematin, and I know that modified myoTisematin and 

 enteroheematin are very like haemochromogen : it was for that reason 

 that I gave them their present names ; but apart from the fact that^ 

 as I have just stated^ no haemoglobin can be found in some animals 

 where they occur, there remains the no less important one, that they 

 do not behave chemically, as they ought to do, if they were meta- 

 bolites of hsemoglobin. 



* Philos. Trans., loc. cit. 



