LABORATORY MANUAL OF PHYSIOLOGY. 



5. Reduced Haemoglobin. (a) Add to a dilution of de- 

 fibrinated blood in which the two absorption bands distinctly 

 show, a few drops of ammonium sulphid. Warm gently. The 

 solution changes color, becoming purple or wine color. Examine 

 the spectrum of this solution and compare it with that of oxy-haemo- 

 globin. Open the vial containing the reduced haemoglobin solu- 

 tion, and shake it vigorously with air. Does the solution change 

 color? Observe the spectrum. Has it changed? Is this change 

 permanent or only temporary ? 



(b) Dilute the solution still further. Does the broad absorp- 

 tion band resolve into several or does it simply fade as the blood 

 becomes more dilute? 



6. CO-haemoglobin. (a) Through a dilute solution of de- 

 fibrinated blood, showing the absorption bands of oxy-haemoglo- 

 bin, pass a stream of CO gas. Note the characteristic change in 

 color from the bright scarlet of oxy-haemoglobin to the cherry red 

 of CO-haemoglobin. 



(b) Test the illuminating gas of the laboratory for carbon mon- 

 oxide in this way. 



(c) Observe the spectrum of the blood so treated. Does it dif- 

 fer markedly from that of oxy-haemoglobin ? Make a sketch show- 

 ing the relations of the absorption bands. 



(d) Add a reducing agent, as was done in obtaining reduced 

 haemoglobin. Is there any effect upon the color of the solution or 

 upon its spectrum ? What conclusion can you draw concerning the 

 stability of this haemoglobin compound ? How does it compare in 

 stability with oxy-haemoglobin? Why is coal-gas poisoning so 

 dangerous ? 



7. Methsemoglobin. To a medium dilute solution of de- 

 fibrinated blood, showing the two absorption bands of oxy- 

 haemoglobin, add a few drops of potassium-permanganate 

 solution. Observe the spectrum. If the oxy-haemoglobin bands 

 still persist, add more of the permanganate and warm gently. 

 Acidify the solution and look for the spectrum of methaemo- 

 globin. 



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