54 PHYSIOLOGICAL AND PATHOLOGICAL CHEMISTRY. 



cleavage takes place not only in solutions of hemoglobin, but 

 also in blood itself. 



To show the formation of hsematin add about 1 cc. of 

 caustic soda solution to 8 or 10 cc. of diluted blood (1 : 5), and 

 heat: the solution, which at first is almost cherry-red, turns 

 brown-green. When examined with the spectroscope the 

 light is found to be entirely absorbed up to a part of the red. 

 The spectrum, on further dilution, is not very characteristic; 

 at the proper concentration it consists of a broad, poorly 

 defined band in the orange between C and D. On the addi- 

 tion of one to two drops of ammonium sulphide or Stokes's 

 solution this absorption-band disappears and the two sharply 

 defined and intense absorption-bands of the reduced hsematin 

 or hsemochromogen (No. 5 in the Table of Absorption Spectra) 

 appear. These have approximately the same position as 

 those of the oxyhsemoglobin, but lie nearer to the violet end of 

 the spectrum. The band nearer to the red is narrower and 

 more sharply defined, that towards the violet is broader, less 

 intense, and not so sharply defined. 



IX. Haemin l (Haematin Hydrochloride), C 32 H 31 ClN 4 Fe0 3 . 



Small quantities of hsemin are most readily obtained in the 

 following manner: 75 cc. of glacial acetic acid, previously 

 saturated with salt, are heated in a flask on the water-bath 

 to 90, then 25 cc. of blood are added quite gradually and 

 with constant shaking; continue the heating at 90 for about 

 ten minutes, then pour into a beaker and let stand for twenty- 

 four hours. The hsemin will be found on the bottom of the 

 beaker in the form of an intensely bluish-black layer of glit- 

 tering crystals. (Examine under the microscope.) 



The supernatant fluid is siphoned off, the crystals are 

 washed once with glacial acetic acid, then with acetic acid 



1 Nencki calls this substance acethsemin and gives it the formula 

 C 34 H 33 N 4 FeClO 4 . O. 



