BLOOD ANALYSIS 



297 



a bright red to violet-red. The oxyhemoglobin has been reduced through the 

 action of Stokes' reagent and hemoglobin (so-called reduced hemoglobin) has 

 been formed. This has been brought about by the removal of some of the loosely 



FIG. 87. ANGULAR-VISION SPECTROSCOPE ARRANGED FOR ABSORPTION ANALYSIS. 



combined oxygen from the oxyhemoglobin. Examine this hemoglobin spectro- 

 scopically. Note that in place of the two absorption bands of oxyhemoglobin we 

 now have a single broad band lying almost entirely between D and E. This is 

 the typical spectrum of hemoglobin. If the solution showing this spectrum be 



FIG. 88. DIAGRAM OF ANGULAR-VISION SPECTROSCOPE. (Long.) 



The white light F enters the collimator tube through a narrow slit and passes to the 

 prism, P, which has the power of refracting and dispersing the light. The rays then pass to 

 the double convex lens of the ocular tube and are deflected to the eyepiece E. The dotted 

 lines show the magnified virtual image which is formed. The third tube contains a scale 

 whose image is reflected into the ocular and shown with the spectrum. Between the light 

 F and the collimator slit is placed a cell to hold the solution undergoing examination. 



shaken in the air for a few moments it will again assume the bright red color of 

 oxyhemoglobin and show the characteristic spectrum of that pigment. 



3. Carbon Monoxide Hemoglobin. The preparation of this pigment may be 

 easily accomplished by passing ordinary illuminating gas 1 through defibrinated 



1 The so-called water gas with which ordinary illuminating gas is diluted contains usu- 

 ally as much as 20 per cent of carbon monoxide (CO). 



