114 Schunck . — The Chemistry of Chlorophyll . 
and repeating the process with chloroform and alcohol so as 
to free the substance entirely from adhering fatty matter. 
The crystals are very regular in shape, of a deep orange or 
red colour by transmitted light with a golden lustre by 
reflected light. This beautiful and interesting substance, the 
properties of which have been studied by Bougarel and others, 
yields solutions of a golden-yellow colour which, when suffi- 
ciently dilute, show two tolerably well-defined bands, one on 
the line F, the other between F and G , whilst at the red end 
of the spectrum not a trace of an absorption band can be 
seen, however strong the solution may be, though the band 
between B and C does appear when the solution is not quite 
pure, i.e. when it still contains traces of chlorophyll or of 
chlorophyll-derivatives. Hence it appears probable that 
the other xanthophylls, if they could be isolated and ob- 
tained in a state of purity, would like this one show no bands 
at the red end of the spectrum. On the other hand, the 
bands seen at the blue end probably do not belong to chlo- 
rophyll, strictly speaking, but to one of the xanthophylls. 
The bands of chrysophyll do not, however, as might have 
been supposed, exactly coincide with those at the blue end of 
the ordinary chlorophyll-spectrum, being a little nearer the red 
end. Tschirch surmises that chrysophyll does not pre-exist 
in the green leaf, but is formed by the action of acids either 
from chlorophyll itself or from one of the xanthophylls ac- 
companying it. If this be the case it would account for the 
non-appearance of the chrysophyll-bands in ordinary extracts 
of green leaves. Solutions of chrysophyll are bleached on 
exposure to air and sunlight almost as easily as are those 
of chlorophyll ; still its presence may be detected, if spectro- 
scopic observation only may be relied on, in the yellow alco- 
holic extracts of faded leaves \ 
It is perhaps one of the xanthophylls to which is due the 
glucose reaction observed by myself 1 2 several years ago after 
1 According to Amaud (Compt. Rend. CII. 1119, and CIV. 1293), chrysophyll 
is identical with carotin, the yellow colouring matter of carrots. 
2 Proceedings of Roy. Soc. XXXVI. 183. 
