518 CHEMISTRY OF THE PROTEIDS CHAP. 



It is necessary therefore to distinguish between the ' natural 

 hsematin ' obtained by the action of dilute acids on haemoglobin, and 

 the ' artificial hsematin ' prepared from hsemin. 



In many cases Kiister has observed the analysis of 'artificial 

 hsematin ' to give too low a reading for hydrogen, and is not certain 

 whether the correct formula for * hsematin ' is not 



C 34 H 32 6 N 4 Fe. 

 This formula he derives from hsemin according to the equation : 



C 34 H 33 4 N 4 ClFe + NaOH + - C 34 H 32 5 N 4 Fe + H 2 + NaCl. 

 Kiister has further obtained a de-hydro-hsematin : 



C 3i H 32 4 N 4 Fe, 



by precipitating with dilute acids de-hydrochlorid-hsemin dissolved 

 in alkalies or in alkaline carbonates. De-hydro-hsematin cannot be 

 converted into hsemin. 



Kiister l has also prepared the acetic acid and hydrobromic acid 

 esters ; Nencki and Zaleski 2 several esters of hsemin, such as the 

 dimethyl-, ethyl-, and mono-amyl-ester. Nencki and Zaleski believed 

 the hsemin prepared by Schalfejew's 3 method to be the acetyl-ester of 

 hsemin, but this, according to Zaleski 4 and Kiister, 5 is not the case. 

 The readiness with which hsemin forms addition-compounds depends 

 on the presence of two hydroxyl groups. 6 The oxidation-products of 

 the different hsemins are identical, according to Kiister. 7 



Kiister 8 has also succeeded in introducing up to eight molecules of 

 anilin, C 6 H 5 . NH 2 , into hsemin by boiling hsemin with anilin. At first 

 four molecules of anilin are introduced by removing eight hydrogen 

 atoms by oxidation, yielding the compound C 58 H 52 4 N 8 Fe, and later 

 another two or four molecules of anilin are joined with a simultaneous 

 addition of water and the splitting off of a molecule of ammonia 

 yielding a compound ' anilinohsemin ' with the formulae : 



C 70 H 66 5 N 9 Fe and C 82 H 79 O 5 N u Fe. 

 Although there may be some doubt as to the exact number of 



1 W. Kiister, Ber. d. deutsch. chem. Ges. 29. I. 821 (1896). 



2 M. Nencki and J. Zaleski, Zeitschr. f. physiol. Chem. 30. 384 (1900). 



3 M. Schalfejew, Maly's Jahresberichte, 15. 138 (1885) ; compare also H. U. Robert, 

 Wirbeltierblut in mikrokristallinischer Hinsicht, Stuttgart, Enke, 1901. 



4 J. Zaleski, Zeitschr. f. physiol. Chem. 37. 54 (1902). 



5 W. Kiister, ibid. 40. 391 (1903). 



6 M. Nencki and Zaleski, ibid. 3O. 384 (1900). 



7 W. Kiister, ibid. 29. 185 (1900). 



8 William Kiister, ibid. 40. 423 (1904). 



