1897 - 98 .] Dr D. F. Harris on Spectroscopy of Haemoglobin. 193 
VI . — On the Spectra of those Pigments ivhose Absorption-Bands 
closely resemble those of Hb0 2 or its Derivatives. 
1. Carmine. — Waller (7) says, “The discovery of a two-banded 
spectrum is not proof positive that Hb0 2 is the colouring agent, 
for carmine gives a very similar spectrum.” Dr Waller admits 
that they could only he confused upon hurried examination. 
A solution of borax-carmine in standard hsematinometer was 
diluted till of the same transparency as a *3 per cent, solution of 
Hb0 2 ; it showed the following differences from blood : — 
(1) Each of the bands of carmine has its edges more hazy and 
ill-defined than the blood-bands. 
(2) Carmine lets some blue light through ; Hb0 2 does not. 
(3) More green light passes in the case of carmine. 
(4) Concentrated solutions of carmine allow some violet light 
to pass ; blood does not : carmine has a narrow zone 
of green at E. 
(5) The interlinear green light is, in all strengths of carmine, 
deficient, while it is markedly present in the weaker 
solutions of Hb0 2 , 
(6) The wave-lengths of the bands of carmine are — 
The left-hand band from A566 to A.538, centre at A.553. 
The right-hand band from A.522 to A.500, centre at A.51 1. 
2. Magenta. — This aniline dye, soluble in water, is in concen- 
trated solutions very like HbO or Hb0 2 , of strength greater than 
1 per cent. On dilution, the single broad band obscuring the 
orange and yellow regions gives way to two bands, remarkably 
similar to those of hsemochromogen. The right-hand band in the 
case of the magenta is, however, broader, fainter, and farther to 
the right in the green than is the corresponding band of hsemo- 
chromogen, while the left-hand band is rather broader than the left 
of the two of the blood-pigment. 
3. Roseine and Fuchsine are like magenta ; they remind one, at 
a certain degree of dilution, of hsemochromogen. The appearance, 
however, is hardly that of two bands ; it would be more accurately 
described by saying that there is one very broad absorption area, 
whose darkest portion corresponds in position to the left-hand band 
