404 



A further proof of the merely molecular change of the 

 Haemoglobin caused by carbonic acid gas is seen in this — that, 

 as Heynsius found, addition of a minute quantity of ammonia, 

 and then of Stokes' fluid, gives reduced Haemoglobin, as 

 proved by the spectroscope, this on agitation giving the 

 bands of Oxyhemoglobin in all their original intensity. 



I think it is pretty clear that it is the body, with its two 

 perfectly characteristic lines formed by the action of carbonic 

 acid gas on a dilute solution of Haemoglobin, which Hoppe- 

 Seyler meant to indicate as Methaemoglobin. No one appears 

 to have obtained it free from mixture Avith Oxy haemoglobin 

 till now, excepting Heynsius, who mistook it for acid Hsema- 

 tin ; and no one hitherto, whether regarding it as Methasmo- 

 globin or some distinct body, has recognised the broad band 

 in blue belonging to it, and now described. 



I now must mention that it is difficult to get Methsemo- 

 globin free from Oxyhsemoglobin. There seems to be a very 

 strong union between the two, so that after you have formed 

 some Methsemoglobin in a solution, it combines, by a kind of 

 chemical adhesion, with the remaining Oxyha^moglobin, and 

 further action is stopped. This is the case if a strong solution 

 of Haemoglobin is used and COo gas passed through it. A four- 

 banded liquid is the result, having the two bands of Methse- 

 moglobin and the two bands of Oxyhaemoglobin also. Such 

 a solution, if left to itself for a day, has a tendency to revert 

 entirely to Ha:^moglobin by the development of ammonia and 

 self-reduction. I found, however, tliat after COo gas had 

 been long passed (eight hours) through such a solution, and 

 the bands of Oxyha?moglobin were still persisting, so as to 

 give a four-banded liquid, the addition of a very small quan- 

 tity of acetic acid in a dilute state determined the complete 

 transformation of the Oxyheemoglobin into Methajmoglobin, 

 and thus a pure two-banded solution having only the Methse- 

 moglobin bands could be obtained. It was clearly shown 

 that the acetic acid had not, Avhcn added in this Aveak form, 

 proceeded to break up the Haemoglobin as in the formation of 

 Haomatin, since no precipitate of an albumen was obtained on 

 neutralization with ammonia, but the Avliole was readily 

 reconvertible to Oxy haemoglobin, as narrated above. 



There is no doubt that Sorby's Brown Cruorin,^ Avhich was 

 described as three-banded, is a mixture of Methaemoglobin 

 and Oxyhaemoglobin. The product of the action of nitrites 

 on Haemoglobin, discovered by Dr. Arthur Gamgee, is also 



' Since making these observations I am glad to find that Mr. Sorbj lias 

 adopted somewhat similar views, and has confirmed the discovery of a fourtli 

 band in what he and others had considered a three-banded body. 



