516 CHEMISTRY OF THE PROTEIDS CHAP. 



brown; they are insoluble in water, hardly soluble in ether, and 

 slightly soluble in alcohol and chloroform, according to Bialobrzeski. l 



Haemin bears to haematin the same relation as does an ester to a 

 tertiary alcohol, as the halogen is very readily split off by alkalies. 

 The acid character of haematin is, further, conditioned by a hydroxyl 

 group, which is not the same as the one which is replaced by the 

 halogen in converting haematin into haemin. The chlorine is bound 

 therefore, according to Kiister, 2 in the haemin, to a carbon and not 

 to a nitrogen atom. Nencki and Sieber 3 were, however, the first to 

 point out that the chlorine was probably united to carbon or to iron. 



On the assumption that the haematoporphyrin molecule is built 

 up of two hsemopyrrol molecules, and that the two haematoporphyrin 

 molecules in haemin are kept together by the iron-atom present in 

 haematin, Nencki and Zaleski give the following formula for haemin : 



CH 3 C C CH= C(OH) O=C CH=CH C C CH a 



HC 



FeCl 



HC CH 



NH 



NH 



CH 3 C C CH=C(OH) C=C CH=CH C C CH 3 



HC CH HC CH 



\/ \/ 



NH . NH 



Six distinct empirical formulae have been given to haemin : 4 



Nencki and Sieber's amyl-alcohol extract : C 32 H 31 3 N 4 ClFe. & 



Acet-haemin of Schalfejew : C 34 H 33 4 N 4 ClFe. 5 



/3-haemin of Morner : C 34 H 35 4 N 4 ClFe. 6 



Hsemin (Cloetta, Eosenfeld) : C 30 H 35 3 N 3 ClFe. 7 



v. Zeynek, after peptic digestion : C 34 H 34 4 N 5 ClFe. 8 



Kiister's haemin : C 34 H 33 4 N 4 ClFe. 4 



1 M. Bialobrzeski, Ber. d. deutsch. chem. Ges. 29. III. 2842 (1896). 

 >2 W. Kiister, ibid. 29. I. 821 (1896). 



3 M. Nencki and N. Sieber, Schmiedeberg's Arch. f. exper. Path. u. Plmrm. 20. 

 326 (1886). 



4 W. Kiister, Zeit. f. physiol. Chem. 40. 391 (1904). 



5 Nencki and Sieber, Arch. f. experim. Path. u. Pharm. 18 401 ; 20. 325 ; 24. 

 430 (1884-1888). 



6 Morner, Nordisk med. Ark. Festband, 1897, Nos. 1 and 27. 



7 Cloetta, Arch.f. exp. Path. u. Pharm. 36. 352 (1895). See also Kosenfeld, ibid.. 

 40. 137 (1898). 



8 v. Zeynek, Zeit. f. physiol. Chem. 30. 126 (1900). 



