98 PHARMACEUTICAL BOTANY 
in special protoplasmic structures, as chloroplasts, chromoplasts 
or chromatophores, or dissolved in the cell sap. Of the pigments 
named, the following will be considered: Chlorophyll, Xantho- 
phyll, Chromophyll, Carotin, Etiolin, Anthocyanin, Phyco- 
cyanin, Phycophzin, and Phycoerythrin. 
Fic. 54.—Absorption spectra of five different concentrations of chlorophyll a. 
The strongest is represented by the lowest spectrum. (From Palladin after Willstatter 
and Stoll.) 
CHLOROPHYLL is a collective name given to the two green 
pigments found in the chloroplastids or chromatophores of 
leaves or other green parts of plants. Its composition is not 
definitely known although it yields products similar to the 
haemoglobin of the blood when decomposed. Iron is known to 
be essential to its formation and Magnesium, Carbon, Hydrogen, 
Oxygen and Nitrogen are components of it. If green leaves 
be boiled in water to kill the plasma membranes, the water 
poured off, strong alcohol added and the leaf material allowed 
to macerate in the alcohol for some time, an alcoholic extract 
of the green leaves can be obtained. Ifa portion of this alcoholic 
extract of green leaf be diluted with water to an 85 per cent. 
alcoholic solution and xylene or benzine be gradually added 
and the mixture shaken, the pigments in solution will break up 
