Carbonic-oxide-hcemoglobin, &c., in the Magnetic Field. 509 



A compound of iron, which would float easily along with the blood 

 current through the vessels, could only be secured by the iron being 

 taken up by so large an organic molecule." 



When oxy-haemoglobin is subjected to the action of acids and alkalies 

 it splits up with great ease into a coloured iron-containing body and 

 into an albuminous body (or mixture of such bodies). The former, to 

 which the name of Haematin has been given, is a derivative of the 

 molecular group existing in the blood-colouring matter, upon which its 

 colour, its spectroscopic characters, and its physiological properties 

 doubtless depend, though it is a derivative which is unquestionably a 

 product of oxidation, and in no sense represents the real hcemochromogen. 

 According to Hoppe-Seyler, the empirical formula of haematin is 

 CsJJssOsN^Fe, whilst according to Nencki its composition is repre- 

 sented by the formula CssB^C^^Fe. 



When the decomposition of oxy-haemoglobin is effected by glacial 

 acetic acid in the presence of alkaline chlorides, a perfectly crystalline 

 substance separates, which has been hitherto known under the name 

 of hcemin, but which we shall now, following the suggestion of Nencki, 

 term acethcemin. This body was looked upon by Hoppe-Seyler as a 

 hydrochloride of haematin ; the recent researches of Nencki and 

 Zaleski have shown that acethaemin contains 8*59 of iron, and possesses 

 a composition represented by the formula Cs^^O^^dFe ; it con- 

 tains an acetyl group, and both the acetyl and chlorine in it are 

 linked to the iron. When this body is dissolved in weak solutions of 

 sodium hydrate in the cold, the chlorine and acetyl are separated, and 

 on neutralisation with acids, haematin of composition CssB^OJS^Fe is 

 obtained. It is with these two coloured iron-containing decomposition 

 products of haemoglobin, haematin and acethaemin, that my observations 

 have been carried out. Before referring to these in detail, I wish again 

 to insist that these oxidation-products in no sense represent the un- 

 altered iron-containing group to which the blood-colouring matter owes 

 its physiological properties. As Hoppe-Seyler showed, when haemo- 

 globin is decomposed by acids and alkalies in the absence of all traces of 

 oxygen, haematin is never formed, but a colouring matter which pos- 

 sesses the same spectrum as that which had previously been described 

 by Stokes as that of reduced haematin. 



This substance Hoppe-Seyler called haemochromogen, and he ex- 

 pressed the opinion that it constitutes the veritable coloured radical 

 upon which the physiological properties of haemoglobin depend. The 

 experimental facts advanced by Hoppe-Seyler have always appeared to 

 me absolutely inadequate to warrant this hypothesis, which, however, 

 is most suggestive, and demands a thorough and a new investigation. 



