78 PHYSIOLOGICAL CHEMISTRY. 



presence of air, forming a purple-red liquid. The iron is here 

 split off and the new coloring matter, called licematoporpliyrin by 

 HOPPE-SEYLER, is iron-free. The hgematin yields with concentrat- 

 ed sulphuric acid, in the absence of air, a second iron-free coloring 

 matter called hcsmatolin (HOPPE-SEYLER). Haematoporphyrin may 

 also be prepared by the action of glacial acetic acid saturated with 

 hydrobromic acid on haemin crystals (NENCKI and SIEBER). This 

 coloring matter is, according to NENCKI and SIEBER, an isomer 

 of the bile-coloring matter bilirubin, and the formula is, according 

 to them, C 16 H 18 N 2 3 . The formation of haematoporphyrin from 

 haematin occurs according to the following equation : 



CaE.NAFe + 2H 3 - Fe = 2(C 16 H 18 N 3 3 ). 



The combinations of haematoporphyrin with Na and with HC1 

 have been obtained as crystals by NENCKI and SIEBER. The 

 haematoporphyrin prepared by them does not seem to be identical 

 with that prepared by HOPPE-SEYLER even though they have the 

 same spectrum. A dilute solution with alkali carbonate shows a 

 spectrum with four absorption-bands, namely, a band between 

 and D\ a second, broader, surrounding D and with its broadest 

 part between D and E\ a third, lighter and narrower, between D 

 and E\ and lastly a fourth, broad and dark band between b and F. 

 By the action of reducing agents on haematoporphyrin a coloring 

 matter has been obtained which stands closely related to urobi- 

 lin (HOPPE-SEYLER, NENCKI and SIEBER). Haematoporphyrin 

 occurs also in the animal kingdom preformed (MAcMu^K). 



Haemin, H^SMI^ CRYSTALS, or TEICHMANK'S CRYSTALS. Hae- 

 min, according to HOPPE-SEYLER, is a combination between hae- 

 matin and hydrochloric acid, having the formula C^Hggl^FeOs.HCl. 

 NEKCKI and SIEBER designate as haemin, on the contrary (see page 

 77), a body not yet isolated, of the formula C 32 H 30 N 4 Fe0 3 , which 

 may be considered as haematin H 2 or C 32 H 32 N 4 Fe0 4 H 2 0. 

 The haemin crystals are, according to the latest views, a combina- 

 tion of this substance, haemin, and HC1, according to the formula 



According to the same experimenters,the hgemin crystals are a double com- 

 bination with the solvent, amyl alcohol or acetic acid, which is used in their 

 preparation; while HOPPE-SEYLEB claims that the solvent is only held me- 



