252 HEMOGLOBIN. 
rays of the solar spectrum, oxidised hamiochromogen is, in solutions of much 
greater concentration, remarkably transparent for the ultra-violet. 
Hoppe-Seyler made the observation that perfectly pure solutions of haematin 
are quite unaffected by reducing agents, but that the addition of certain foreign 
matters {e.g. albumin) renders reduction possible. I can, from my own re- 
peated observations, emphatically confirm this fact. 
It has been stated above that diluted blood and solutions of oxyhsemoglobin 
treated with acids exhibit a band in the red between C and D (of which the 
centre is approximately situated at X 6-tO), though it varies somewhat with the 
nature of the acid which has effected the decomposition. If, however, blood 
be treated with glacial acetic acid, and the mixture at once shaken with ether, 
the latter subsequently separates, holding so much of an acid compound of 
hsematin in solution as to possess a deep red colour. This ethereal solution, 
in addition to the characteristic band of acid hsematin, exhibits three other 
bands whose positions and relative intensities are indicated in Plate II., 
Spectrum 6. 
Hsematin hydrochloride (st/n, haemin). — When a minute drop of 
blood on a glass slide is mixed with a drop or two of glacial acetic 
acid, and the mixture is boiled over a tiny flame, and then allowed 
to evaporate, the residue is found on microscopic examination to 
contain innumerable reddish-brown prismatic crystals, which were 
formerly constantly referred to as Teiehmann's 1 crystals (after their 
discoverer). Such crystals may be obtained from any old blood stain 
on cloth, linen, wood, metal, etc. The stained tissue or the scrapings 
of the stain are heated, as above, with glacial acetic acid. It is neces- 
sary, however, in the case of stains which may have been subjected 
to the action of water, to add a minute crystal of sodium chloride 
to the glacial acetic acid before boiling. Hoppe-Seyler 2 subsequently 
discovered methods of obtaining Teiehmann's crystals in quantities, 
which enabled him to examine their physical properties with some 
degree of completeness and to analyse them, and he was able to show 
that hsemin is a compound of haematin and hydrochloric acid, to which, 
as a result of his more recent researches, he ascribed the empirical 
formula C 34 H 35 N 1 Fe0 5 HCl. Nencki and Sieber, 3 on the other hand, 
assigned to lnemin the formula C^H.^X^FeOyHCl, corresponding to the 
formula C 3 .,H 30 N 4 FeO 3 , which they assign to hsematin. 
Method of preparing Jicemin in bulk. — A method for preparing hsemin in 
bulk was, as has been said, first devised by Hoppe-Seyler, and other methods 
were described by Xencki and Sieber. These methods demand the ex- 
penditure of much time, labour, and patience ; and none of them, as I know 
from my own abundant personal experience, yield a product which can 
compare in the absolute uniformity of its crystallisation and the complete 
absence of all amorphous matter with the one described by Schalfijew, which 
is as follows : — 
One volume of defibrinated and strained blood is added to four volumes of 
glacial acetic acid, previously heated to 80 3 C. As soon as the temperature has 
fallen to 55°-60°, the liquid is again heated to 80° C. On cooling, crystals at 
once separate, and can be seen floating in the liquid, presenting a charac- 
1 Ztschr.f. rat. Med., 1853, Bd. iii. S. 375, and Bd. viii. S. 141. 
2 Virchow's Archiv, 1864, Bd. xxix. S. 597-600; "Das Hamin," Med.-chem. Unter- 
such., Berlin, S. 379-385. 
3 Arch.f. exper. Path. u. Pharmacol, Leipzig, 1884, Bd. xviii. S. 401 ; 1886, Bd. xxi. 
S. 325 ; 1888, Bd. xxiv. S. 430. 
