258 HEMOGLOBIN. 
well as the colouring matters of the red-blood corpuscles, all contain 
haemochromogen, 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." x 
In other words, Hoppe-Seyler announced that, from his experiments 
it might be concluded that haemochromogen represented an iron-con- 
taining coloured radical, which, by linking itself to an albuminous residue 
or albuminous residues, forms haemoglobin, and that haeroochromogen in 
the latter body combining with a molecule of oxygen forms oxyhemo- 
globin : with a molecule of carbonic oxide, carbonic-oxide haemoglobin, 
etc. — these substances containing oxyhaeinochroroogen and CO-hsemo- 
chromogen respectively. 
Not only are the facts wanting which 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, haemochromogen, 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 haemochromogen does not exist preformed in 
haemoglobin and its compounds. I trust shortly to throw more light 
on this question. 
Liuossier - 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 Jaderholni and by Hoppe- 
Seyler in the case of CO) XO exerts no action on hsematin, but appears to form 
a compound with haemochromogen, which is possessed, as Liuossier describes, 
of a tine red colour, and exhibits two absorption-bands between D and E, 
similar to those of oxyhemoglobin. This XOdiaeniochromogen awaits a careful 
examination. 
Hoppe-Seyler has speculated in reference to the condition in which the 
iron exists in haemochromogen 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 
H.EMATOPOEPHYPIX. 
Methods of preparation. — When either lueinatin or haemin 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 haematoporphyrin. In this operation the acid 
separates the whole of the iron from the haematin, and it is found in 
solution in the state of a, ferrous salt. In the process of decomposition 
of haematin by sulphuric acid there is no evolution of hydrogen gas. 
From haematin and haemin haematoporphyrin can also be obtained — 
(1) by the action of strong HC1 in sealed tubes heated to 130° C. 
1 Hoppe-Seyler, Ztschr.f. physiol. C'hem., Strassburg, Bd. xiii. S. 492 and 493. 
2 " Sur une combinaisou de l'h<5matine avee le bioxyde d'azote," Compt. rend. Acad. d. 
sc, Paris, tome civ. p. 1296. 
3 For the discussion of the question, see Hoppe-Seyler, Med.-chem. Untcrsuch., Bciliu, 
S. 546-559. 
