HANDBOOK FOR BIO-CHEMICAL LABORATORY. 21 



Dilute solutions show a spectrum with two absorption-bands 

 between the Fraunhofer lines D and E. The one band, a, 

 which is narrower but darker and sharper, lies on the line D\ 

 the other, broader, less defined and less dark band, ft, lies at 

 E. Oxyhaemoglobin solutions are reduced by reducing solu- 

 tions such as ammonium sulphide, ammoniacal ferro-tartrate 

 solution (Stokes reduction liquid) yielding a characteristic 

 spectrum of haemoglobin. 



Haemoglobin. 







Preparation. Fill a cylinder nearly full with a dilute 

 watery solution of oxyhaemoglobin, and add a few drops of a 

 putrefied extract of meat. Close up hermetically, and allow to 

 stand some time at the ordinary temperature. The oxyhaamo- 

 globin will be reduced to haemoglobin, and if the solution is of 

 the proper concentration a crystallization of haemoglobin may 

 occur in the cylinder at lower temperatures. The solution 

 of haemoglobin is more purple than a solution of oxyhaemo- 

 globin, and shows a spectrum with only one absorption-band 

 occupying the space between the Fraunhofer lines D and E. 



Carbon-monoxide Haemoglobin. 



Preparation. Pass a current of carbon monoxide (pre- 

 pared by heating a mixture of sulphuric and oxalic acids and 

 passing the gases through a wash-bottle containing KOH), 

 through a watery solution of oxyhaemoglobin. The color of 

 the solution becomes lighter, due to the formation of carbon- 

 monoxide haemoglobin. The spectrum of the solution is not 

 changed, but it differs from the oxyhaemoglobin in that it 

 cannot be reduced by reducing solutions into haemoglobin. 

 The crystals are isomorphous to the oxyhaemoglobin crystals, 

 but are less soluble. 



