Wakeman—Pigments of Flowering Plants. 897 
which it appears to play in photosynthesis. Notwithstanding, 
however, the abundance of material available, the importance of 
the problem and the attention paid to it, np until quite recently, 
but little light has been thrown upon the subject and even now 
the chemistry of chlorophyll is far from being elucidated. 
It is not at all the purpose of this paper to discuss the com¬ 
plex chemistry of chlorophyll, nor is this necessary in view of 
the very thorough revision of the subject by MarchiewsM, 1 pub¬ 
lished in 1909, and the yet more recent one by Willstaetter 2 in 
1913. A brief mention of the subject, however, is not out of 
place and seems desirable in order to place chlorophyll in its 
class among the plant pigments. 
Chlorophyll, according to Willstaetter, is a complex magne¬ 
sium compound, or rather, a mixture of at least two such com¬ 
plex compounds, the blue green chlorophyli-a, C 55 H 72 0 5 N 4 Mg, 
and the yellow green chlorophyll-b, C 55 H 70 O 6 N 4 Mg. 
Both of these chlorophylls are esters of phytol, which is a 
constant constituent of chlorophyll. Phytol is an open chain 
primary alcohol of the formula of saturation C n H 2n . The fol¬ 
lowing structural formula has been suggested for phytol: 
CHa—CH—CH—CH-—CH—OH—CH—CH—C = C—CH 2 O H 
ill i i i i i i 
OH 3 CH, CH 3 CH 3 CH 3 CHa CH, CH 3 CH 3 
Making it, according to the Geneva Congress system of 
nomenclature, nonmethyl-2, 3, 4, 5, 6, 7, 8, 9, 10-undecene-2-ol-l. 
By the action of an anzyme, chlorophyllase, chlorophyll-a is 
hydrolised yielding phytol and chlorophyllid-a 
C 20 H 39 OH MgN 4 O 32 H 80 OCOOCH 3 COOH 
Phytol Chlorophyllid-a 
while chlorophyll-b yields phytol and chlorophyllid-b. 
C 20 H 39 OH MgN 4 C 32 H 0 COOCH 8 COOH 
Phytol Chlorophyllid-b 
Phytol is a non-colored substance and appears to play no di¬ 
rect part in pigmentation. 
s Dle Chemie der Chlorophyll, Braunschweig, 1909. 
* Untersuchungen ueber Chlorophyll, Berlin, 1913. 
57—S. A. Ii. 
