25$ HEMOGLOBIN. 



well as the colouring matters of the red-blood corpuscles, all contain 

 hsemochromogen, and this body can be obtained from them all by a 

 process of simple decomposition, even in the crystalline condition, and 

 almost in theoretical proportions." l 



In other words, Hoppe-Seyler announced that, from his experiments 

 it might be concluded that hremochromogen represented an iron-con- 

 taining coloured radical, which, by linking itself to an albuminous residue 

 or albuminous residues, forms haemoglobin, and that hsemochromogen in 

 the latter body combining with a molecule of oxygen forms oxyhsemo- 

 globin ; with a molecule of carbonic oxide, carbonic-oxide haemoglobin, 

 etc. these substances containing oxyhsemochromogen and CO-hsemo- 

 chromogen respectively. 



Not only are the facts wanting whiah would be needed in order to 

 prove this hypothesis, but there are many others which appear to me 

 to indicate that whilst, when once formed, hsemochromogen, as indeed 

 hsematin, includes the specific atomic group upon which the character- 

 istic optical and physico-physiological properties of the blood-colouring 

 matter depend, probably hsemochromogen does not exist preformed in 

 haemoglobin and its compounds. I trust shortly to throw more light 

 on this question. 



Linossier 2 described compounds of hsematin and reduced hsematin with 

 nitric oxide as well as with carbonic oxide. On repeating his experiments, 

 I convinced myself that (as had been shown by Jaderholm and by Hoppe- 

 Seyler in the case of CO) JSTO exerts no action on hsematin, but appears to form 

 a compound with hsemochromogen, which is possessed, as Linossier describes, 

 of a fine red colour, and exhibits two absorption-bands between D and E, 

 similar to those of oxyhsemoglobin. This NO-hflemochromogen awaits a careful 

 examination. 



Hoppe-Seyler has speculated in reference to the condition in which the 

 iron exists in hsemochromogen and hsematin respectively, and has emitted the 

 opinion that the iron in haemochromogen is present in a ferrous and in hsematin 

 in a ferric condition, but the grounds for an opinion do not actually exist. 3 



HJ^MATOPORPHYRIN. 



Methods of preparation. When either hsematin or hsemin is 

 thoroughly mixed with concentrated sulphuric acid, it dissolves, and 

 by filtering through asbestos a clear and beautiful purple-red solution 

 is obtained. When this solution is poured into a large quantity of 

 water, the greater part of the dissolved colouring matter is precipitated 

 in the form of a brown flocculent precipitate, the quantity of which 

 increases if alkalies be added so as to neutralise the acid. This colour- 

 ing matter is impure hsematoporphyrin. In this operation the acid 

 separates the whole of the iron from the hsematin, and it is found in 

 solution in the state of a ferrous salt. In the process of decomposition 

 of hsematin by sulphuric acid there is no evolution of hydrogen gas. 



From hsematin and hsemin hsematoporphyrin can also be obtained 

 (1) by the action of strong HC1 in sealed tubes heated to 130 C. 



1 Hoppe-Seyler, Ztschr. f. physiol. Chem., Strassburg, Bd. xiii. S. 492 and 493. 



2 " Sur une combinaison de i'he'matine avec le bioxyde d'azote," Compt. rend. Acad. d. 

 sc., Paris, tome civ. p. 1296. 



3 For tbe discussion of the question, see Hoppe-Seyler, Med.-ckem. Untcrsuch. , Berlin, 

 S. 546-559. 



