154 BLOOD. 



5. Alkaline Met-Hsemoglobin.-To (4) add 2 or 3 drops of 



strong ammonia. The colour turns ruby red. A band 

 on the red side of and cut by D and another in the 

 green. 



A blood-stained rag is given to you. Examine by cutting 

 out a small piece of the stain 0*5 S(1 cm and steeping it in the 

 least quantity of normal saline on a slide. Search for (1) 

 red blood cells, (2) absorption bands (microspectroscope if the 

 quantity is very small), (3) hremin crystals. 



DECOMPOSITION SPECTRA OF HAEMOGLOBIN. 



6. Aeid Haematin. To a bottleful of blood solution add ten 



drops of acetic acid. Slight warming hastens the change. 

 The heat of the flame near the bottle on the spectro- . 

 scope stand will do this. Note the alteration in the 

 colour brown tint. One band well in the red is 

 characteristic with some obscuration of the green. 



7. Alkaline Hsematin. To a bottleful of blood solution add 



ten drops of a 10 p - c - solution NaOH. Warm in a tube 

 to hasten the change. One broad band to the red side 

 of and cut by the D line. Hsematin in ethereal solution 

 gives a four-band spectrum. 



8. Reduced Hsematin. (Stokes' reduced hsematin, heemo-chro- 



mogen.) Treat (6) with a few drops of (NH 4 ) 2 S. It changes 

 to reduced hsematin. Two bands in the green the band 

 nearer D is the darker of the two and persists longest 

 with dilution. 



9. Haematopopphyrin in acid solution. Add four drops of 



undiluted defibrinated blood to 3 cm strong H 2 SO 4 in a tube, 

 agitate. The solution must remain clear, and present a 

 deep cherry-red colour (iron-free hsematin). Two bands 

 a thin one to the red side of and touching D, and a 

 broader one on the other side of and shading off towards 

 D. The latter persists longest with dilution. 



