I PROPOSE to show in this book that a man's natural abilities are derived
by inheritance, under exactly the same limitations as are the form and
physical features of the whole organic world. Consequently, as it is easy,
notwithstanding those limitations, to obtain by careful selection a permanent
breed of dogs or horses gifted with peculiar powers of running, or of doing
anything else, so it would be quite practicable to produce a highly-gifted
race of men by judicious marriages during several consecutive generations.
I shall show that social agencies of an ordinary character, whose influences
are little suspected, are at this moment working towards the degradation of
human nature, and that others are working towards its improvement. I
conclude that each generation has enormous power over the natural gifts of
those that follow, and maintain that it is a duty we owe to humanity to
investigate the range of that power, and to exercise it in a way that, without
being unwise towards ourselves, shall be most advantageous to future
inhabitants of the earth.