re able to
evolve modes of defense equal to the modes of attack possessed by their
enemies. Many, unable to evolve the acute senses and the fleet limbs
necessary for the combat on the ground, shrank from the fray and
acquired more negative and passive means of defense. Some, like the bat,
escaped into the air. Others, such as the squirrel and the ape, took
refuge in the trees.

It was in this concourse of weak creatures which fled to the trees
because they lacked adequate means of offense, defense, or escape on the
ground that the lineaments of man's ancient ancestor might have been
discerned. One can imagine what must have been the pressure from the
carnivora that forced a selective transformation of the feet of the
progenitor of the anthropoids into grasping hands. Coincidentally with
the tree life, man's special line of adaptation--_versatility_--was
undoubtedly rapidly evolved. Increased versatility and the evolution of
hands enabled man to come down from the trees millions of years
thereafter, to conquer the world by the further evolution and exercise
of his organ of strategy--the brain. Thus we may suppose have arisen the
intricate reactions we now call mind, reason, foresight, invention, etc.

Man's claim to a superior place among animals depends less upon
_different_ reactions than upon a _greater number_ of reactions as
compared with the reactions of "lower" animals. Ability to respond
adaptively to more elements in the environment gives a larger dominion,
that is all.

The same measure applies within the human species--the number of nervous
reactions of the artist, the financier, the statesman, the scientist,
being invariably greater than the reactions of the stolid savage. That
man alone of all animals should have achieved the degree of versatility
sufficient for such advance is no more remarkable than that the elephant
should have evolved a larger trunk and tusks than the boar; that the
legs of the deer should be fleeter than those of the ox; that the wings
of the swallow should outfly those of the bat. Each organism, in
evolving the combination of characters commensurate with safety in its
particular environment, has touched the limit of both its necessity and
its power to "advance." There exists abundant and reliable evidence of
the fact that wherever man has been subjected to the stunting influences
of an unchanging environment fairly favorable to life, he has shown no
more disposition to progress than