Contributions to the theory of natural selection. A series of essays ... By Alfred Russel Wallace ...

SELECTION ON MAN. 315
and finally become extinct. But man guards himself
from such accidents by superintending and guiding
the operations of nature. He plants the seed of his
most agreeable food, and thus procures a supply, independent of the accidents of varying seasons or natural extinction. He domesticates animals, which serve
him either to capture food or for food itself, and thus,
changes of any great extent in his teeth or digestive
organs are rendered unnecessary. Man, too, has everywhere the use of fire, and by its means can render
palatable a variety of animal and vegetable substances,
which he could hardly otherwise make use of; and thus
obtains for himself a supply of food far more varied and
abundant than that which any animal can command.
Thus man, by the mere capacity of clothing himself, and making weapons and tools, has taken away
from nature that power of slowly but permanently
changing the external 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.