158 Journal of Agricultural Research voi. ix, n 0 . 6 - 
In another place (4) the same author reports that plants growing in 
media lacking manganese remained colorless or very pale and that by 
adding manganese in increasing proportions a corresponding increase 
in green color resulted. 
Stoklasa, Brdlik, and Just (10), in repeating former work, reaffirm 
their earlier 1 conclusion that phosphorus plays an important r 61 e in the 
production of chlorophyll. Their method of procedure was to extract 
the leaves with benzol and to determine the phosphorus in the extract. 
One of the authors above cited, Brdlik (1), states that the physio¬ 
logical action in plants indicates a close relation between phosphorus 
and chlorophyll in the plant cell. He also states that alcohol and benzol 
extracts of green leaves show inorganic phosphorus as well as colorless 
phosphates, indicating that phosphorus plays a very important r 61 e in 
chlorophyll formation. It is his opinion that phosphorus plays as im¬ 
portant a part in the physiological activity of the plant as magnesium 
or potassium. 
Schryver (9) states that chlorophyll is a magnesium derivative from 
which the metal is eliminated readily by acids, but with great difficulty 
by alkalies. 
Palladine (8) studied the influence of various carbohydrates on chloro¬ 
phyll formation. Etiolated plants of Vida faba and Phaseolus vulgaris , 
after being kept in the dark for 48 hours, were brought into the light. 
He states that the following substances favored the formation of chloro¬ 
phyll: Saccharose, raffinose, glucose, fructose, maltose, glycerin, ga¬ 
lactose, lactose, and dextrin. The following substances checked the 
formation of chlorophyll: Mannite, dulcite, asparagin, urea, alcohol, 
ammonium chlorid, and quinic acid. 
Maz6, Ruot, and Lemoigne (7) state that they produced chlorotic con¬ 
ditions in Vida narbonnensis by adding 0.2 per cent of calcium carbonate 
to the culture medium, which condition -was neutralized in three days 
by applying a few drops of iron nitrate to the leaves. 
There are apparent contradictions in the findings of some of these 
authors. Wills tatter states (11) that the chlorophyll of all plants con¬ 
tains magnesium and no other metal; Mameli (5, 6) that plants became 
chlorotic in the absence of manganese; Stoklasa et al. (10) that phosphorus 
plays an important part in the formation of chlorophyll. 
It may be that the confusion on the subject is increased by mistaking 
an indirect influence of some of the above-mentioned elements for a direct 
one. For instance, iron was for a long time considered an essential con¬ 
stituent of chlorophyll, and, while it was later found not to be the case, 
iron is known to be quite essential in the formation of the green pigment 
in plants. 
Palladine’s results (8) on chlorophyll formation as influenced by various 
carbohydrates may be of great practical importance in orcharding. 
Especially may this be so in a system under so thorough control as the 
