THE CHLOROPHYLL APPARATUS 149 
position are generally found with it in the chloroplast. One 
of these, Xanthophyll, which is of a bright yellow colour, is 
always extracted with the chlorophyll by alcohol. It can 
be separated from the extract by appropriate means, and 
its solution yields the absorption spectrum represented 
below those of chlorophyll in fig. 84. Another pigment, 
Erythrophyll, is present in those leaves which are found upon 
the trees in autumn. Like xanthophyll, it appears to be 
a product of the decomposition of chlorophyll, and it has a 
spectrum which differs from both the others. 
It is extremely difficult to say what is the chemical 
composition of chlorophyll, on account of the readiness with 
which it is decomposed. In all the processes which have 
been adopted for its extraction it undergoes decomposition, 
and consequently no defimite conclusions as to its chemical 
nature can at present be arrived at. It can be made to 
yield definite crystals by appropriate methods of treatment 
after extraction, but it is probable that these crystals are 
a derivative of chlorophyll and not the pure pigment. 
Analyses of the crystals have been made by Gautier and by 
Hoppe-Seyler, who give them the following percentage 
compositions :— 
Gautier. Hoppe-Seyler. 
C 738-97 73°34 
H 98 9-72 
N 4:15 5°68 
O 10°38 9-54 
Ash 1-75 1-72 
According to Hoppe-Seyler the ash contains phosphorus 
and magnesium. 
From his analysis Gautier came to the conclusion that 
chlorophyll is related to the colouring matter of the bile ; 
Hoppe-Seyler considered, on the other hand, that it is a 
fatty body allied to lecithin. 
Wilstatter found that the phosphorus of the ash is an acci- 
dental impurity, and hence that chlorophyll is not related 
