244 



PHYSIOLOGICAL CHEMISTRY 



this reagent. The reagent must be freshly prepared.) The color 

 becomes darker red. The oxyhemoglobin has been reduced to 

 hemoglobin. Pour the blood in one of the Stokes' reagent tubes 

 several times from one test tube to another. The brighter oxy- 

 hemoglobin color reappears. Evidently hemoglobin and oxy- 



7 



FIG. 2. ABSORPTION SPECTRA. 



1. Spectrum of sunlight showing Fraunhofer lines. 



2. Oxyhemoglobin (0.37%). 



3. Hemoglobin. 



4. CO-hemoglobin. 



5. Methemoglobin. 



6. Acid hematin (in ether). 



7. Hemochromogen (reduced alkaline hematin). 



8. Acid hematoporphyrin. 



hemoglobin are readily converted one into the other. Consider 

 this property in connection with the role which hemoglobin plays 

 in the organism. 



