DERIVATIVES OF HEMOGLOBIN. 37 



or Stokes's fluid, the spectrum of reduced haemoglobin 

 appears, and on shaking up with air, the bands of oxy- 

 hsemoglobin appear. 



16. VII. Hsematoporphyrin. (Iron-free Hsematin.) 



(a.) Place some concentrated sulphuric acid in a test-tube, 

 add some blood, and examine with the spectroscope. Or 

 examine a solution obtained by dissolving some hsematin in 

 concentrated sulphuric acid, and filtering through asbestos 

 when a clear purple-red solution is obtained. 



(6.) Observe two absorption bands, one close to and on the 

 red side of D, and a second half-way between D and E. 



(c.) To some of the hsematin solution (in strong sulphuric 

 acid), add a large excess of water, which throws down part 

 of the hsematoporphyrin in the form of a brown precipitate, 

 which is more copious if the acid be neutralised with an 

 alkali e.g., caustic soda. Dissolve some of the brown 

 deposit in caustic soda, and examine it spectroscopically. 



(d.) The spectrum shows four absorption bands; a faint 

 band midway between C and D, another similar one between 

 D and E, but close to D ; a third band near E ; and a fourth 

 one, darkest of all, occupying the greater part of the space 

 between b and F, but nearer the former. 



In all cases make drawings of what you see, and compare 

 them with the table of characteristic spectra suspended in the 

 Laboratory. 



LESSON V. 



WAVE-LENGTHS DERIVATIVES OF 



HAEMOGLOBIN ESTIMATION OF 



HEMOGLOBIN. 



Spectroscopic Determination of Wave-Lengths. Use Zeiss's 

 spectroscope, which is provided with an illuminated scale for 

 this purpose. 



