PERSONALITY OF PLANTS 
pulsive power greater than the blood pressure 
of the strongest animal. 
Above the roots and the stem of the develop- 
ing plant are the branches. Their function is 
too well known to need much comment. They 
raise the leaves up into the air and the light. 
They act as conduits for ascending and descend- 
ing sap. ‘They give the plant strength and rig- 
idity. Each main stem is a clever bit of plant 
engineering, so built as to withstand all kinds of 
heavy strains and stresses. 
The leaves of our seedling are extremely im- 
portant parts of its anatomy. Pluck them off 
and it will die in a few hours. ‘They are 
mouths, stomachs and lungs all in one. Their 
surfaces are broad and flat, in order that they 
may catch and devour every particle of car- 
bon dioxide which comes their way. To us, 
carbon dioxide is a negligible part of the at- 
mosphere, but out of this intangible product 
of combustion, arising from fires, breathed out 
by animals and expelled by volcanoes and hot 
springs, the tallest tree builds its greatest struc- 
ture. Is it any wonder that it takes so long! 
In the inner tissue of each leaf is a substance 
[32] 
