514 CHEMISTRY OF THE PROTEIDS CHAP. 



chloroform with a bluish-violet colour. Goldmann, Helper, and 

 Marchlewski 1 showed subsequently that the substance in question is 

 the hydrochloride of ha3mopyrrol-diazodibenzene. The free azo-dye, 

 on the supposition that haemopyrrol is really methyl-propyl-pyrrol 

 and not another homologue of pyrrol, has this constitution : 



CHo C C CqHhr 



O O I 



C-N 2 -C 6 H 5 



NH 



Haemopyrrol-di-azoditoluene was prepared analogously. 



Haematoporphyrin can therefore be built up directly from four 

 molecules of haemopyrrol or of one of its oxidation-products. That 

 this synthesis is the only possible one, seems further to be proved 

 by the fact that neither Nencki 2 nor Kiister 3 found any other 

 dissociation-products besides haemopyrrol and the haematinic acids. 

 The maximum yield of hsemopyrrol 2 and of the haematinic acids 3 

 obtained from haematoporphyrin at first only amounted to 32 and 

 50 per cent respectively, and Kiister, 4 being able to account for only 

 16 out of the 34 C-atoms and for only 2 out of the 4 N-atoms by the 

 two haematinic acids, C 8 H 9 4 N (respectively C 8 H 8 5 ), concluded that 

 only one-half of the hasmatin was a substituted pyrrol, but when 

 Zaleski showed that mesoporphyrin contained the whole of the carbon, 

 namely 340, Kutscher 5 realised that his old view was wrong, and 

 that greater importance will have to be attached to the haematinic 

 acids than has been done in the past. On reinvestigating the forma- 

 tion of haematinic acids (see p. 512) he now holds that at least three 

 molecules of C 8 H 9 4 N, if not indeed four molecules, can be obtained 

 from haematin. 



Description of the Individual Dissociation-products : 

 Hsemin 



Haemin was first prepared by Teichmann in 1853 by the action of 

 glacial acetic acid and a little sodium chloride on warmed blood. 6 



1 H. Goldmann, J. Hetper, and L. Marchlewski, Zeits. f.phys. Chem. 45. 176 (1905). 



2 M. Nencki and J. Zaleski, Ber. d. deutsch. chem. Ges. 34. I. 997 (1901). 



3 M. Kolle, Dissertation, Tubingen, 1898. 



4 W. Kuster, Zeitschr. f. physiol. Chem. 28. 1 (1899), and 29. 185 (1900). 



5 W. Kutscher, ibid. 44. 391 (1905). 



6 L. Teichmann, Zeitschr. /. rat. Med. N.F. 3. 375 (1853) ; 8. 141 (1857). 



