xternal form and structure, in accordance with
changes in the external world, which she exercises over all other
animals. As the competing races by which they are surrounded, the
climate, the vegetation, or the animals which serve them for food, are
slowly changing, they must undergo a corresponding change in their
structure, habits, and constitution, to keep them in harmony with the
new conditions--to enable them to live and maintain their numbers. But
man does this by means of his intellect alone, the variations of which
enable him, with an unchanged body, still to keep in harmony with the
changing universe.

There is one point, however, in which nature will still act upon him as
it does on animals, and, to some extent, modify his external characters.
Mr. Darwin has shown, that the colour of the skin is correlated with
constitutional peculiarities both in vegetables and animals, so that
liability to certain diseases or freedom from them is often accompanied
by marked external characters. Now, there is every reason to believe
that this has acted, and, to some extent, may still continue to act, on
man. In localities where certain diseases are prevalent, those
individuals of savage races which were subject to them would rapidly die
off; while those who were constitutionally free from the disease would
survive, and form the progenitors of a new race. These favoured
individuals would probably be distinguished by peculiarities of
_colour_, with which again peculiarities in the texture or the abundance
of _hair_ seem to be correlated, and thus may have been brought about
those racial differences of colour, which seem to have no relation to
mere temperature or other obvious peculiarities of climate.

From the time, therefore, when the social and sympathetic feelings came
into active operation, and the intellectual and moral faculties became
fairly developed, man would cease to be influenced by "natural
selection" in his physical form and structure. As an animal he would
remain almost stationary, the changes of the surrounding universe
ceasing to produce in him that powerful modifying effect which they
exercise over other parts of the organic world. But from the moment
that the form of his body became stationary, his mind would become
subject to those very influences from which his body had escaped; every
slight variation in his mental and moral nature which should enable him
better to guard against adverse circumstances, and