The microscope has shown that a drop of water though it may appear to
the naked eye to be perfectly clear, is swarming with living beings.
According to Ehrenberg, a cubic inch of water may contain more than
800,000 millions of these beings, estimating them only to occupy one
fourth of its space; and a single drop, placed under the microscope,
will be seen to hold 500 millions; an amount, perhaps, not so very far
from equal to the whole number of human beings on the surface of our
globe!
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