THE 
NEW PHYTOhOGIST. 
Vol. XIV, No. 10. December, 1915. 
[Published January 21st, 1916]. 
CARBON ASSIMILATION. 
A Review of Recent Work on the Pigments of the 
Green Leaf and the Processes connected with them. 
By Ingvar Jorgensen and Walter Stiles. 
(Continued from p. 250). 
B. The Chemistry of Chlorophyll. 
Chlorophyll is a neutral substance which on treatment with 
alkalis yields salts of acids which are known as chlorophyllins. 
These salts of the chlorophyllins are soluble in water and are also 
green in colour like chlorophyll. In the production of chlorophyllins, 
a group which was hound to an acid radicle, has been split off from 
the chlorophyll molecule, that is, the chlorophyll has undergone 
saponification like an ester. 
The chlorophyllins which are formed by alkaline hydrolysis 
from alcoholic extracts of leaves are easily decomposed. They 
were, however, isolated by Willstatter, and were found on analysis 
to contain magnesium, which was bound to the nitrogen in a 
complex way. The magnesium cannot be electrolytically disso¬ 
ciated as in a magnesium salt. The magnesium containing group 
is very easily affected by acids, but is stable in presence of alkalis. 
On heating chlorophyllins with concentrated alcoholic alkalis, 
a series of decomposition products, phyllins, are obtained by 
removal of carboxyl groups, until in the final phyllin only one 
remains. The phyllins are also acids containing magnesium. On 
removal of the last carboxyl group a substance devoid of oxygen, 
Eetiophyllin, is produced, having the composition C 3l H 34 N 4 Mg, in 
which also the magnesium is bound to the nitrogen. 
If mineral acids and acetic acid are allowed to act on the 
phyllins, these lose their magnesium. The series thus obtained 
