prevent the friendly contest from developing into a fierce struggle for
individual physical dominance.

But man gained his pre-eminent position among the animals mainly through
his ability to form co-operative groups working to common ends; and long
before the times of which anthropological research give us any clear
knowledge, man had turned his individualistic fighting instincts to the
service of his group or clan. That is to say, he had become a warrior,
giving his best strength to co-operative aggression in behalf of
satisfactions that could not be won by him as an individual acting for
himself.

Our earlier studies have taught us also that if man's instinctive
tendencies could in any manner be inhibited or modified, so that he came
to display other characteristics than those observed in the present
expression of these inborn instincts, then the law of his nature would
in that very fact be changed. We are thus led to ask whether the
biologist finds evidence that an animal's instincts can be thus changed
in mode of expression.

The biologist speaks to us somewhat as follows. Although new racial
characteristics have very rarely, if ever, been gained by the
obliteration of instincts, changes in racial characteristics have not
infrequently occurred as the result of the control, rather than the
loss, of these inherited instincts.

This control may become effective in either one of two ways: first, by
the thwarting or inhibition of the expression of the instincts; or
secondly, by the turning of its expression to other uses than that which
originally resulted in its fixation.

As an example of the thwarting of the expression of an instinct we may
take the functioning of the sexual instinct, which, as we see it in
animals in general, has been inhibited in the human animal by the habits
acquired by man as he has risen in the scale.

This mode of change--that of the mere chaining of the instinctive
tendency--is subject to one great difficulty. The chain may by chance be
broken; the inhibition may be removed; then the natural instinctive
tendency at once shows itself. Remove the restraints of civilized
society but a little, and manifestations of the sexual instinct of our
race appear in forms that are not far removed from those observed in the
animal. Place a man under conditions of starvation and he shows himself
as greedy as the dog.

The second mode of change--that of the transference of functioning of
the instin