Effect of Light on Vegetation 
The scientific basis for this chapter is found in work being 
done at Boyce-Thompson Institute for Plant Research at 
Yonkers, N. Y., by Dr. John M. Arthur and his associates. 
(T 9 HE greatest factory in the world is the green leaf of the plant. 
X In it, in light, the carbon dioxide of the air, with water and the 
inorganic compounds of the soil, is manufactured into starches and 
sugars—carbohydrates of one sort or another—that form the basis 
of all the foodstuffs of all the world. Every animal must draw its 
sustenance from plants in some way, for animals cannot manu¬ 
facture the foods they need. In their bodies they arrange plant 
foods into animal materials; but the green plant alone can take 
gases from the air, mineral matter and water from the soil, and 
then, activated by the tremendous energy of the sun, can trans¬ 
form these inorganic materials into organic energy suitable for 
plant and animal food. 
Foods made by the plant may be used at once in the processes of 
growth, flowering and setting seed, or the plant may store the 
manufactured materials in its body. The plant body, built up by 
this food storage, gives us wood with all its uses, coal, natural oil 
and gas, besides all the things into which these may be divided. It 
is the stored foods that tie up the sun’s energy and hold it until a 
new process releases it. The source of energy in this great factory 
Editorial Note—Much of the valuable information which is being secured from the 
experiments conducted by the scientists at the Boyce-Thompson Institute will be of vital 
assistance to plant growers in the Southwest, as their deductions explain why certain plants 
that flourish in other locations fail to thrive here. This Institute was founded about seven 
years ago by the late Colonel William Boyce-Thompson, and has already become famous for 
its findings on seed germination, on the control of blight, on locating the cause of mosaic 
disease, and on the speeding up of growth and fruiting of shrubs and plants. This article 
has been contributed by Persis S. Crocker, wife of Dr. William Crocker, Director of the 
Institute. 
Photo- 
Synthesis 
99 
