surroundings--that all our political development from the tribal
organisation of the Stone Ages to the modern nation has apparently been
due.

The biologist looks on human nature itself as changing, but to him the
period of a few thousands or tens of thousands of years which constitute
the past of politics is quite insignificant. Important changes in
biological types may perhaps have occurred in the history of the world
during comparatively short periods, but they must have resulted either
from a sudden biological 'sport' or from a process of selection fiercer
and more discriminating than we believe to have taken place in the
immediate past of our own species. The present descendants of those
races which are pictured in early Egyptian tombs show no perceptible
change in their bodily appearance, and there is no reason to believe
that the mental faculties and tendencies with which they are born have
changed to any greater degree.

The numerical proportions of different races in the world have, indeed,
altered during that period, as one race proved weaker in war or less
able to resist disease than another; and races have been mingled by
marriage following upon conquest. But if a baby could now be exchanged
at birth with one born of the same breeding-stock even a hundred
thousand years ago, one may suppose that neither the ancient nor the
modern mother would notice any startling difference. The child from the
Stone Age would perhaps suffer more seriously than our children if he
caught measles, or might show somewhat keener instincts in quarrelling
and hunting, or as he grew up be rather more conscious than his fellows
of the 'will to live' and 'the joy of life.' Conversely, a transplanted
twentieth-century child would resist infectious disease better than the
other children in the Stone Age, and might, as he grew up, be found to