HAEMATIN. 291 



oxyhsemoglobin, and is, therefore, found in the 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 hsematin is formed by the decom- 

 position of oxyhsemoglobin, or at least of haemoglobin, in the presence 

 of oxygen. 



The views in regard to the composition of hsematin are rather con- 

 tradictory, which seems to be due to the fact that the substance hsemin 

 (see below), from which the formula of hsematin is derived, has a some- 

 what different composition, dependent upon various conditions. Accord- 

 ing to HOPPE-SEYLER hsematin has the formula C34H34N4FeOs, and 

 from the recent investigations upon hsemin, 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/ hsematin has the formula 

 , with 1 atom of iron for every 3 atoms of nitrogen. 



v. ZEYNEK has prepared a haematin by the digestion of an oxyhsemoglobin 

 solution with pepsin-hydrochloric acid, from which he then prepared hsemin. 

 As this hsematin of v. ZEYNEK was readily convertible into hsemin, and while the 

 ordinarily prepared haematin from hsemin cannot be retransformed into hsemin, 

 KUSTER considers that these two forms of hsematin are not identical. The 

 first he calls a-hsematin and the ordinary which is a polymeric 'body, he calls 

 ^-hsematin. That a retransformation of hsemin is possible from ordinary haematin 

 is still admitted by PILOTY and ELLiNGER. 2 



Hsematin contains at least three hydroxyl groups, one of which acts 

 as hydroxyl ion and seems to be united with the iron, and is replaced 

 in the hsemin 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 hsemin derivatives) have been especially studied by NENCKI 

 and ZALESKI and KusTER. 3 Hsematin dissolves in concentrated sulphuric 

 acid and is converted into hsematoporphyrin, 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 hsematin and the 

 question as to the constitution of hsematin will be discussed in connec- 

 tion with hsematoporphyrin. 



Hsematin 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. 

 iiber den Blutfarbstoff. Dissert. Munchen, 1907. 



3 Nencki and Zaleski, Zeitschr. f. physiol. Chem., 30; Kuster, Ber. d. d. Chem. 

 Gesellsch. -13 and 45, and Zeitschr. f. physiol. Chem., 82. 



