THE BLOOD. 



57 



glass slip, a crystal of common salt added, and a drop of 

 glacial acetic acid poured over it, the hsematin will unite 

 with some hydro-chloric acid liberated, and form character- 

 istic crystals called haemin crystals. 



The Spectrum of Hemoglobin. 



Another characteristic property of haemoglobin is its 

 absorption lines when viewed with a spectroscope. When 

 ordinary white light is viewed with a spectroscope it is 

 broken up into those characteristic colors with which we 

 are familiar as the spectrum. If, now, such a beam of 

 ordinary light be passed through a solution of oxyhsemo- 

 globin before reaching the spectroscope, the spectrum is not 

 complete; but there appear two very dark black lines in 

 that part of the spectrum where the red shades over into 

 the yellow and that into the green. If now the oxygen be 

 taken out of the oxyhsemoglobin and a ray of light passed 

 through this venous haemoglobin be examined, there 

 appears in the spectrum one dark band, in position almost 

 exactly between the two stripes of the oxyhsemoglobin. 

 This single absorption band for the haemoglobin, and the 

 two bands for the oxyhaemoglobin are so characteristic that 



Oxyhaemogflobin. 



CO- haemoglobin. 



Fig. 11. SPECTRUM OF HEMOGLOBIN AND ITS COMPOUNDS. (C, D, E, etc., Fraunhofer 

 lines.) 



