There is more than one bit of evidence that nature changed her plan with reference to some organism at the very last moment, and introduced a feature which was not contemplated at the outset.  This change of plan is carried out through the specialization of some organ, sense, or habit, to such a degree as to make practically a new type of the organism.  In the human species, for example, the atrophied organs distributed through the body are evidence that the physical make-up of the species was well-nigh definitely fixed before the advantage of free hands led to an erect posture, thereby throwing certain sets of muscles out of use; 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