74 Schunck . — The Chemistry of Chlorophyll. 
phyll-bands, others are of opinion that they belong to a yellow 
colouring matter accompany ing chlorophyll, and generally called 
xanthophyll. Kraus 1 , who has paid much attention to this part 
of the subject, states that he succeeded by treating ordinary 
alcoholic chlorophyll-solutions with benzol in obtaining two 
colouring matters, one of which gives yellow non-fluorescent 
solutions with two absorption-bands at the blue end of the 
spectrum (xanthophyll), the other bluish-green fluorescent 
solutions showing, along with the usual bands at the red end, 
two absorption-bands at the blue end, but not in the same 
place as those of the other colouring matter (kyanophyll). 
R. Sachsse 2 repeated Kraus’s experiment, using benzin from 
petroleum, but failed in obtaining a solution of the yellow 
colouring matter so free from the other as not to show the 
first chlorophyll-band ; this band always appearing when the 
solution was sufficiently concentrated. In my opinion the 
bands at the blue end of the spectrum do not belong to 
chlorophyll, — adopting for the latter the definition with which 
I started, — but to yellow colouring matters associated with it. 
My opinion is partly founded on the fact that it is possible 
to isolate a colouring matter from leaves in regular lustrous 
crystals, which gives yellow solutions showing two distinct 
bands in the blue when sufficiently dilute, but no bands what- 
ever in the red, yellow, or green, however concentrated they 
may be. It is probable that ordinary chlorophyll-solutions 
contain several yellow colouring matters in addition to those 
giving definite spectra. 
Is Chlorophyll a Homogeneous Substance, or does 
it consist of Several Substances having very 
Similar Properties? 
This question may be here referred to, because the opinion 
that chlorophyll is a mixture of several substances is founded 
principally on observation of its absorption-spectrum. With 
1 Zur Kenntniss d. Chlorophyllfarbstoffe. Stuttgart, 1872. 
2 Die Chemie u. Physiologie d. Farbstoffe, u. s. w. Leipzig, 1877. 
