; and the specialization of the
voice as a means of communicating thought was, similarly, a device
for relieving the hands of the burden of communication, and was not
introduced systematically until a gesture language had been so
well established that even now we fall back into it unconsciously,
especially in moments of excitement, and attempt to talk with our
hands and bodies.

But perhaps the most interesting modification or reversal of plan to
be noted in mankind is connected with the relation of the two sexes.
As will presently be indicated, life itself was in the beginning
female, so far as sex could be postulated of it at all, and the
life-process was primarily a female process, assisted by the male. In
humankind as well, nature obviously started out on the plan of having
woman the dominant force, with man as an aid; but after a certain
time there was a reversal of plan, and man became dominant, and woman
dropped back into a somewhat unstable and adventitious relation to
the social process. Up to a certain point, in fact, in his physical
and social evolution man shows an interesting structural and mental
adaptation to woman, or to the reproductive process which she
represents; while the later stages of history show, on the other
hand, that the mental attitude of woman, and consequently her forms
of behavior, have been profoundly modified, and even her physical life
deeply affected, by her effort to adjust to man.

The only attitude which nature can be said to show toward life is the
design that the individual shall sustain its own life, and at death
leave others of its kind--that it shall get food, avoid destruction,
and reproduce. In pursuance of this policy it naturally turns out that
those types showing greater morphological and functional complexity,
along with freer movement and more mental ingenuity, come into the
more perfect control and use of their environment, and consequently
have greater likelihood of survival. Failing of this greater
complexity, their chance of life lies in occupying so obscure a
position, so to speak, that they do not come into collision with more
dominant forms, or in reproducing at such a rate as to survive in
spite of this. The number of devices in the way of modification of
form and habit to secure advantage is practically infinite, but all
progressive species have utilized the principle of sex as an accessory
of success. By this principle greater variability is secured, and
a