time be crowded out by its competitor. Worms are
eaten by lower vertebrates, and these by higher. An animal's
environment, like that of a merchant or manufacturer, is very
largely a matter of the ability and methods of its competitors. And
man, compelled to live in society, makes that part of the
environment by which he is most largely moulded.

This process of extinction Mr. Darwin has called "natural
selection." Natural selection is not a force, but a process,
resulting from the combined action of the forces of environment. It
is not a cause in any proper sense of the word, but a result of a
myriad of interacting forces. The combination of these forces in a
process of natural selection leading directly to a moral and
spiritual goal demands an explanation in some ultimate cause. This
explanation we have already tried to find.

It is a process of extinction. It favors the fittest, but only by
leaving them to enjoy the food and place formerly claimed, or still
furnished, by the less fit. In any advancing group, as the less fit
are crowded out, and the better fitted gain more place and food and
more rapid increase, the whole species becomes on an average better
conformed. More abundant nourishment and increased vigor seem also
to be accompanied by increased variation. And by the extinction of
the less fit the probability is increased that more fit individuals
will pair with one another and give rise to even fitter offspring,
possessing perhaps new and still more valuable variations.

But if, of a group of weaker forms, those alone survive which adopt
a parasitic life, those which in adult life move the least will
survive and reproduce; there will result the survival of the least
muscular and nervous. This degeneration will continue until the
species has sunken into equilibrium, so to speak, with its
surroundings. Here natural selection works for degeneration. Sessile
animals have had a similar history. But these parasitic and sessile
forms had already been hopelessly distanced in the race for life.
Their presence cannot impede the leaders; indeed their survival is
necessary to directly or indirectly furnish food for the better
conformed. In the animal and plant world there is abundant room and
advantage at the top.

Once more, natural selection works as a rule for the survival of
individuals, only indirectly for that of organs composing, or of
species including, these individuals. It may work for the
development of