Schunck . — The Chemistry of Chlorophyll. 113 
an able summary of what is known on this subject, arrives 
at the conclusion that there are five distinct xanthophylls, 
not including the etiolin of etiolated leaves, which according 
to him differs more widely from the xanthophylls than do 
the latter inter se. I have myself ascertained that the xan- 
thophyll of faded leaves does consist of at least two distinct 
colouring matters, one of which is soluble in alcohol and ether, 
the other soluble in alcohol only ; the first shows the same 
absorption-bands as the erythrophyll of green leaves, the 
latter no bands at all. Much confusion has arisen in con- 
nexion with this subject in consequence of the difficulty of 
separating these colouring matters and of ascertaining what 
bands belong specially to each, spectroscopic observation 
being the only means hitherto employed to distinguish them. 
Some observers maintain that the bands seen at the red end 
in the absorption-spectrum of most of the yellow colouring 
matters belong to them, while others are of opinion that 
these bands are due to an admixture of chlorophyll or 
some derivative of chlorophyll, e.g. phyllocyanin, of which 
a small quantity not otherwise discoverable would suffice to 
produce the absorption, and that, if these xanthophylls could 
be obtained in a state of purity, they would no longer when 
dissolved show any bands at the less refrangible end of the 
spectrum. The latter opinion certainly holds good as regards 
chrysophyll, the only one of the yellow colouring matters of 
leaves that has hitherto been obtained in a state of purity. 
When leaves of any kind are extracted with boiling alcohol 
the extract on standing for some time invariably deposits 
a quantity of minute sparkling red crystals, almost always 
mixed with more or less fatty matter coloured green by 
chlorophyll. These crystals are the chrysophyll of Harsten, 
the erythrophyll 1 of Bougarel. The substance may easily 
be obtained in a state of purity by treating the deposit re- 
ferred to with a little chloroform, filtering, adding alcohol 
to the filtrate, collecting the crystals which form on standing, 
1 The erythrophyll of Berzelius is the substance to which the colour of red 
autumnal leaves is due, and in no way resembles the colouring matter of Bougarel. 
I 
