256 H.EMO.GLOBIX. 
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 luemochroniogen 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 
accoimt of hsemochromogen 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 18S9) as separating in the form of a violet-grey 
powdery precipitate. 
G H K L M N 
50 5 
Fig. 38. — The photographic spectrum of oxygenized hamiochromogen and of 
li a? m ochrom oge n . 
Acids, even when very dilute, lead in the first instance to the forma- 
tion of haemochromogen 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 haemochromogen, as at first described by Hoppe- 
Seyler, 5 when prepared by the action of acids on haemoglobin. 
1 Hammarsten, "Lehrhuch d. phys. Chem.," Dritte Auflage, 1895, S. 122 ; Neumeister, 
"Lehrhuch tier 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. Chan., Strassburg, 1S89, Bd. xiii. S. 495. 
3 Hoppe-Seyler und Thierfelder, " Handbueh d. phys. u. path. Chem. Analyse," 
Berlin, 1893, S. 214, 215 ( " Hamochromogen "). 
4 See Abstract by Hammarsten in Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 
1874, Bd. iv. S. 102. 
•" Med.-chem. Untersueh., Berlin, S. 542. In his later descriptions of the spectrum of 
acid solutions of haemochromogen no mention is made of four bands. 
