in. Each of these changes is in one sense a revolution.

A little before the summer solstice the earth is whizzing away from
the sun; a few weeks later it is whizzing with equal rapidity in
almost the opposite direction. In the very nature of things it could
not be otherwise. But so silently and gradually does it come about
that we never feel the reversal of the engine; indeed the engine has
not been reversed at all. Very similar is the change of the struggle
of brute against brute to that of man for man. Indeed human
development seems now to be almost at such a solstice where the
power that makes for love is almost exhausted in opposing the
tendency toward selfishness. We shall not always stay at the
solstice; soon we shall make more rapid progress. And unselfishness
like the family relation is firmly rooted in mammalian structure.

And man owes almost everything to family life. First the child gains
the advantage of the parent's experience. He is educated by the
parent. In a few formative and receptive years he gains from the
parent the results of centuries of human experience. The process is
thus cumulative, the investment bears compound interest. And yet
this is peculiar to man only in degree. Have you never watched a
cat train her kittens? And the education of the child in the savage
family is very incomplete.

The family is the first and fundamental of all higher social and
political unities. And without the persistence of the family the
larger social unit would become an inert mass. All the individual
ambition, all desire for family advancement, must be retained as
still a motive for energetic advance. And all the training which
social life can give reaches the individual most effectively, or
solely, through the family. Society without the family would be like
an army without company or regimental organization. Thus the very
existence, not only of training in love and mutual helpfulness, but
even of society itself as a mere organization, depends upon the
existence and improvement of family life. And as so much depended
upon and resulted from it, it could not but be fostered and improved
by natural selection. The tribe or race with the best family life
has apparently survived. But all social animals have some means of
communicating very simple thoughts or perceptions. The simplest
illustrations of this are the calls and warning cries of mammals and
birds. It is not impossible that the higher mammals have someth