1897 - 98 .] Dr D. F. Harris on Spectroscopy of Hcemoglobin. 187 
Some Contributions to the Spectroscopy of Haemoglobin 
and its Derivatives. By David Fraser Harris, 
M.D., C.M., B.Sc. (Lond.), “Muirhead” Demonstrator of 
Physiology in the University of Glasgow. 
(Read February 7, 1898.) 
I . — Details of the Preparation of Hb0 2 and its Derivatives , for 
Demonstration to Large Classes. 
1. Apparatus. — The following are needed : — Electric or lime 
light ; standard haematinometer ( i.e n of 1 cm. between the 
parallel sides) entirely of glass (for many pigments white glass 
flat-sided stoppered bottles do perfectly well) ; large direct- 
vision spectroscope (Messrs Hilger), or a Tollen’s carbon- 
disulphide glass prism (base 5 inches, refracting angle 45°) ; a 
well-stretched dead -white screen to receive the spectrum 4 feet 
long at least, about 12 feet from the lantern. 
Following Prey er (1), one can with such apparatus first of all- 
■demonstrate the different spectroscopic appearance according as 
blood is or is not diluted. Placing blood newly received from the 
slaughter-house (defibrinated blood) in the haematinometer, we 
show that if is opaque in a thick layer, no light passes to the 
prism at all, there is no spectrum, we can say that the percentage 
■of Hb0 2 is, at least, greater than 7*3. Dilute with pure cold 
water until a faint gleam of red light appears at the extreme left, 
the concentration of Hb0 2 is now not less than 1 per cent. ; 
continue the dilution until the first glimmer of extra-linear green 
appears, the percentage is now about *9 per cent. ; dilute until the 
first glimmer of intra-linear green appears, when the percentage 
is now *7 ; add to this its own volume of water, making the 
percentage fall to *35. From this point further dilution caused 
progressive faintness of the two bands, until the vanishing point of 
the fainter /3 band is just reached when the haemoglobin is *01 
per cent. ; continue the attenuation until the a band is alone 
visible, at which point the percentage can be stated to be 
■certainly less than *01 per cent. 
