irreversible; but in human society differentiations
are no longer confined to the bodies of individuals
but have become, as it were, extra-corporeal.

By this control over nature man has taken into
his evolution the whole of his environment. Al-
though he is not as strong as the elephant nor as
deft as the spider nor as swift as the antelope nor as
powerful in the water as the whale or in the air as
the eagle, yet by his control of the forces of nature
outside of his body he can excel all animals in
strength and delicacy of movement, in speed and
power on land, in water, and in air.

This new path of progress is in all respects the
most important which has ever been discovered
by organisms, and no one can foresee the end of this
process of annexing to our own powers the illimitable
forces of the universe.

-78-