SCIENCE IN THE PLANT WORLD 
_ gies. Whether by instinct, reason or blind force 
they always know just what to do and how to 
make the most of their heredity and environ- 
ment. Their efficiency rating is one hundred 
per cent. 
As the whole life of all plants is a scientific 
progression, we can only consider in the brief 
limits of this chapter some of the more start- 
ling instances of the marvelous sense they ex- 
hibit in dealing with Nature’s forces. 
Probably one of the reasons we do not always 
think of plants in the human, sympathetic way 
we should, is that we are inclined to regard 
them as quiet, static objects, playthings of ev- 
ery wind that blows upon them. Such is far 
from the case. Life is motion and the plants 
are very much alive and very much in motion. 
From the tiniest cell to the largest tree they 
exhibit constant, pulsating movements. Many 
of the movements are described through so 
small a space as ordinarily to escape our notice, 
but a little observation makes them quite ap- 
parent. They all have a well-directed, scientific 
purpose. 
What is plant growth itself but motion up- 
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