. DERIVATIVES OF HAEMOGLOBIN. 39 



and 0) in this position; the scale is now accurately adjusted 

 for all other parts of the spectrum. 



" The numbers on the scale indicate wave-lengths ex- 

 pressed in one hundred thousandths of a millimetre, and 

 each division indicates a difference in wave-length equal to 

 one hundred thousandth of a millimetre " (Gamgee). 



Thus, Frauenhofer's line, D, which corresponds to division 

 58-9 of the scale, has a wave-length of 589 millionths of a 

 millimetre. The wave-lengths of Frauenhofer's lines are: 

 A = 7604, B = 687-4, = 656-7, D = 5894, E = 527-3, 

 F - 486-5. 



(c.) Using one of the blank maps provided for you (i.e., 

 the maps supplied with Zeiss's spectroscope the maps 

 correspond to the scale seen in the spectroscope), fill 

 in, in wave-lengths, the position of Frauenhofer's lines, B 

 toF. 



(d.) Use a dilute solution of blood or haemoglobin 1 part 

 in 1000 of water is best and place it in the heematinometer, 

 D, which is placed in position between the flame and the 

 spectroscope, as shown in Fig. 6. The distance between the 

 parallel faces of D is 1 cm. The spectrum shows the two 

 absorption bands of oxy-hsemoglobin between D and E. 

 The narrower, sharper, and blacker band near D has its 

 centre corresponding with the W.L. 579, and it may con- 

 veniently be expressed by the letter a of the oxy-hsemo- 

 globin spectrum (Gamgee). 



The other absorption band near E, and conveniently 

 designated (3, is broader, not so dark, and has less sharply 

 defined edges than a. Its centre corresponds to the W.L. 

 553 -8. Notice that the other parts of the spectrum are 

 seen, there being only slight cutting off of the red, and a 

 slightly greater absorption of the violet end. 



(e.) Work with a stronger solution of blood, and observe 

 how the two bands become fused into one, while more and 

 more of the red and violet ends of the spectrum are absorbed 

 as the solution is made stronger, until finally only a little 

 red light is transmitted. 



2. W.L. of Absorption Band of Reduced Hb. 



(a.) Adjust the apparatus as before, but reduce the oxy- 

 hsemoglobin solution with Stokes's fluid noticing the 



