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HiEMATIN. 291
oxyhemoglobin, and is, therefore, found in tlio feces after hemorrhage
in the intestinal canal, and also after a meat diet and food rich in blood.
It is stated that hsematin may occur in urine after poisoning with arseniu-
reted hydrogen. As shown above, the haematin is formed by the decom-
position of oxyhemoglobin, or at least of haemoglobin, in the presence
of oxygen.
The views in regard to the composition of haematin are rather con~
tradictory, which seems to be due to the fact that the substance haemin
(see below), from which the formula of haematin is derived, has a some-
what different composition, dependent upon various conditions. Accord-
ing to Hoppe-Seyler haematin has the formula C34H34N4FeOs, and
from the recent investigations upon haemin, which will be mentioned
below, this formula seems to be now generally accepted. According
to this formula 1 atom of iron occurs with every 4 atoms of nitrogen.
According to Cloetta, and also Rosenfeld,1
hsematin has the formula
CaoH34N3Fe03, with 1 atom of iron for every 3 atoms of nitrogen.
v. Zeynek has prepared a hsematin by the digestion of an oxyhemoglobin
solution with pepsin-hydrochloric acid, from which he then prepared haemin.
As this hsematin of v. Zeynek was readily convertible into haemin, and while the
ordinarily prepared haematin from haemin cannot be retransformed into haemin,
Kuster considers that these two forms of haematin are not identical. The
first he calls a-haanatin and the ordinary which is a polymeric body, he calls
/3-haematin. That a retransformation of haemin is possible from ordinary haematin
is still admitted by Piloty and Ellinger. 2
Haematin contains at least three hydroxy 1 groups, one of which acts
as hydroxyl ion and seems to be united with the iron, and is replaced
in the haemin formation (see below) by the chlorine. By means of the
two others, salts with metals as well as alkyl derivatives may be formed,
which latter (as haemin derivatives) have been especially studied by Nencki
and Zaleski and Kuster.3
Haematin dissolves in concentrated sulphuric
acid and is converted into haematoporphyrin, with the splitting off of
iron. On heating dry hsematin it yields an abundance of pyrrol. The
products produced on the oxidation and reduction of haematin and the
question as to the constitution of haematin will be discussed in connec-
tion with haematoporphyrin.
Haematin is amorphous, dark brown or bluish-black. It may be
heated to 180° C. without decomposition; on burning it leaves a residue
1
Hoppe-Seyler, Med.-chem. Untersuch., p. 525; Cloetta, Arch. f. exp. Path. u.
Pharm., 36; Rosenfeld, ibid., 40.
2
v. Zeynek, Zeitschr. f. physiol. Chem., 30 and 49; Kuster. ibid., 66 and Ber.
d. d. chem. Gesellsch., 43; Piloty, Annal. d. Chem. u. Pharm., 377; Eppinger, Unters.
uber den Blutfarbstoff. Dissert. Munchen, 1907.
5
Xencki and Zaleski, Zeitschr. f. physiol. Chem., 30; Kuster, Ber. d. d. Chem.
Gesellsch. 43 and 45, and Zeitschr. f. physiol. Chem., 82.
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