256 



HAEMOGLOBIN. 



separates as a violet-grey powdery precipitate, which dissolves again in 

 the liquid from which it had separated, as soon as this cools. It is quite 

 erroneous to state, as is asserted in all text-books, 1 that Hoppe-Seyler 

 succeeded in separating hsemochromogen in a crystalline condition. He 

 only succeeded (at most) in obtaining crystals of the CO-compound, 

 and concluded that haemochromogen itself must be a crystalline body, but 

 he never even asserted that he had actually obtained the crystals, and a 

 promise made in 1889 2 to describe the assumed crystalline haemo- 

 chromogen, though implying that he had already obtained the body in 

 this condition, was never fulfilled. Moreover, in the last systematic 

 account of haemochromogen which he published in 1893, Hoppe-Seyler 3 

 does not refer to its being crystalline, but, on the contrary, speaks of it 

 (as he had done in 1889) as separating in the form of a violet-grey 

 powdery precipitate. 



G H K L M N 



* **, w 



111 



"I 



FIG. 38. The photographic spectrum of oxygenized hsemochromogen and of 

 haemochromogen. 



Acids, even when very dilute, lead in the first instance to the forma- 

 tion of hsemochromogen from reduced haemoglobin, in the absence of 

 oxygen ; they, however, decompose a part of the haemochromogen with 

 great rapidity, removing its iron and giving rise to haematoporphyrin. 

 This explains, according to Jaderholm, 4 the complex (four-banded) nature 

 of the spectrum of haemochroinogen, as at first described by Hoppe- 

 Seyler, 5 when prepared by the action of acids on haemoglobin. 



1 Hammarsten, " Lehrbuch d. phys. Chem.," Dritte Auflage, 1895, S. 122 ; Neumeister, 

 "Lehrbuch der physiol. Chem., etc.," 1895, Bd. ii. S. 154 ; Halliburton, "A Text-Book 

 of Phys. Chemistry," 1891, p. 290; Sheridan Lea, "The Chemical Basis of the Animal 

 Body," Appendix to Foster's "Physiology," 1892, p. 232. 



2 Hoppe-Seyler, Ztschr. f. physiol. Chem., Strassburg, 1889, Bd. xiii. S. 495. 



3 Hoppe-Seyler und Thierfelder, "Handbuch d. phys. u. path. Chem. Analyse," 

 Berlin, 1893, S. 214, 215 (" Hamochromogen "). 



4 See Abstract by Hammarsten in Jahresb. it. d. Fortschr. d. Thier-Chem., Wiesbaden, 

 1874, Bd. iv. S. 102. 



5 Med. -chem. Untersuch., Berlin, S. 542. In his later descriptions of the spectrum of 

 acid solutions of hsemochromogen no mention is made of four bands. 



