1 1 2 Schunck . — - The Chemistry of Chlorophyll . 
Substances accompanying Chlorophyll. 
An account of the substances accompanying chlorophyll 
might include all the contents of the leaf-cell. I shall here, 
however, exclude all such substances as are soluble in water 
and confine myself to the yellow colouring matters of leaves 
soluble in alcohol and ether, but insoluble in water. These 
substances usually accompany chlorophyll in ordinary alco- 
holic or ethereal extracts of green leaves, and having some 
properties in common with chlorophyll have been supposed, 
though perhaps without sufficient reason, to be related to it. 
According to the definition of chlorophyll occasionally given 
it would include all the green and yellow colouring matters 
of ordinary leaves. The earlier observers did not indeed 
recognise the simultaneous presence of yellow and green 
pigments in ordinary green leaves. Berzelius 1 supposed that 
the yellow colouring matter of autumnal leaves was formed 
from chlorophyll in consequence of a change in the organisa- 
tion of the leaf induced by cold, and he called it xanthophyll. 
Krauss endeavoured to show that ordinary chlorophyll is 
a mixture of two colouring matters — kyanophyll and xantho- 
phyll, the latter being the substance to which the obscure 
bands at the blue end of the spectrum of ordinary chlorophyll- 
solutions are mainly due. In this case there has fortunately 
been no misuse of terms, there being good reasons to suppose 
that the xanthophyll of autumnal leaves is merely the yellow 
colouring matter left after the fading away of the green, the 
latter being the less stable of the two and disappearing first. 
Still the term xanthophyll, if applied to the yellow pigment 
of etiolated leaves, to the yellow colouring matter accom- 
panying the chlorophyll of green leaves, and to that of yellow 
autumnal ones, granting that these three are virtually the 
same, may after all denote not one, but a group of substances 
having similar properties. As regards the xanthophyll of 
green leaves this is exceedingly probable. Tschirch, after 
1 Ann. d. Pharm. XXI. 261. 
