405 



apparently of the same nature. Dr. Gamgee described it as 

 three-banded, but I find now, on looking for it, what had 

 escaped both me and him, namely, a fourth band in the 

 blue, which comparison by superposition shows to be identi- 

 cal in position with the second band of Methaemoglobin, as 

 here described. The band appeared a little fointer rela- 

 tively than in pure Methajmoglobin in a specimen of the 

 product of nitrite of potassium and Haemoglobin prepared for 

 the purpose of comparison. Tt appears that a little Ha?matin 

 also may be formed in the action of nitrites on Hasmoglobin, 

 as I have mentioned in another paper (' Journal of Anatomy,' 

 November, 1869); but it is not to this only, as I was inclined 

 to think, that the optical properties of nitrite-Haemoglobin 

 arc due. "Whenever Methsemoglobin is formed there is a 

 tendency of the action to proceed further to the formation of 

 Haeinatin, and hence small quantities of Hsematin are usually 

 formed simultaneously with it. Gamgee's nitrite-Hsemoglobin, 

 like Heynsius's product of the action of CO^ on Haemoglobin, 

 and like Sorby's Brown Cruorin, is, as he demonstrated, 

 reconverted to Oxyhoemoglobin by the addition of ammonia, 

 reducing fluid, and agitation. They are all mixtures (per- 

 haps chemically held) of Oxyhfemoglobin and the pure two- 

 banded Methsemoglobin.^ 



The true relation of Metha?moglobin to Haemoglobin and 

 Hsematin is still obscure. I was at one time inclined to regard 

 it as a neutral soluble Hajmatin, but it stands on a higher 

 level than Heematin, no separation of an albuminoid occurring 

 in its formation (Preyer's glohin is possibly due to the forma- 

 tion of small quantities of Haematin). It is most probably 

 Ha-moglobin in but a slightly changed molecular condition, 

 whence its ready formation and reconversion ; whether any 

 loss or addition of chemical components occurs in these 

 changes has to be determined 



' Mr. Sorby, I perceive, in his paper which precedes this, regards the 

 mixtures of Oxyhceinoglobin and Methsenioglobin as Peroxyiisemogiobin. Do 

 not Gamgee's researches on the gas-absorption of this body negative tliis 

 hypothesis ? 



