282 PHYSIOLOGICAL CHEMISTRY 



to orient the absorption bands produced by the hemoglobin solu- 

 tions examined. In making a spectroscopic examination and in 

 charting the result, have the red end of the spectrum always on 

 the left. This avoids confusion and error in interpreting notes. 

 Observe and chart the following lines in your notebook, and in- 

 dicate them on all your spectrum records. From left to right 

 (beginning in the red) B and C, two prominent lines in the red; 

 D, a prominent line in the yellow (really two lines if observed 

 with a delicate spectroscope) . This line corresponds to the bright 

 lines observed above in the sodium spectrum; E and b, two 

 prominent lines in the green ; F at the beginning of the purple. 



37. Examine oxyhemoglobin solutions of various concentra- 

 tions spectroscopically as directed below. Blood contains be- 

 tween 13% and 14% hemoglobin so the percentage concentra- 

 tion of hemoglobin may be calculated for any dilution. The 

 observations are made through a flat sided cell. Each successive 

 dilution may be made by adding an equal volume of distilled 

 water to any volume of the liquid to be diluted. Make observa- 

 tions on blood in the following dilutions : Blood shaken with air 

 and diluted 10 times, 20, 40, 80, 160, 320, 640 and 1280 times. 

 If the solution at a dilution of 1280 still shows two absorption 

 bands, dilute further until only one band remains. Record 

 results. 



38. Spectrum of Hemoglobin. Pour blood diluted 40 times 

 into the cell, reduce it by adding a small amount of Stokes' rea- 

 gent and observe the spectrum. Record. Repeat with blood 

 diluted 80 and 160 times. 



39. Carbon Monoxide Hemoglobin. Prepare a solution of 

 carbon monoxide hemoglobin by diluting blood 160 times, and, in 

 the hood, passing illuminating gas through the liquid. Observe 

 the cherry red color. Observe the solution spectroscopically and 

 chart it, comparing the location of the bands carefully with those 

 given by an oxyhemoglobin solution. To a little of the carbon 

 monoxide hemoglobin solution add Stokes ' reagent. Observe that 

 the spectrum does not change, as did that of oxyhemoglobin, 

 which it resembles, under similar conditions. 



