86 
SEED DISPERSAL. 
nicest way to grow a few cabbages, radishes, squashes, 
cucumbers, or potatoes is to plant a few here and there in 
good soil, at considerable distances from where any have 
heretofore been grown. For a time enemies are not likely 
to find them. I have often noticed that, while pear-blight 
decimated or swept large portions of a pear orchard, a few 
isolated trees, scattered about' the neighborhood, usually 
remain healthy. The virgin soil of the Dakotas produced, 
at a trifling cost, healthy, clean wheat, but it was not long 
before the Russian thistle, false flax, and other pests fol- 
lowed, to contest their rights to the soil. 
As animals starve out, in certain seasons when food is 
scarce, or more likely migrate to regions which can afford 
food, so plants desert worn-out land and seek fresh fields. 
As animals retreat to secluded and isolated spots to escape 
their enemies, so, likewise, many plants accomplish the 
same thing by sending out scouts in all directions to find 
the best places ; these scouts, it is needless to say, are 
seeds, and when they have found a good place, they 
occupy it, without waiting for further instructions. 
56 . Much remains to be discovered. — “ In this, as in 
other branches of science, w r e have made a beginning. 
We have learned just enough to perceive how little we 
know. Our great masters in natural history have immor- 
talized themselves by their discoveries, but they have not 
exhausted the field ; and if seeds and fruits cannot vie 
with flowers in the brilliance and color with which they 
decorate our gardens and our fields, still they surely rival 
