ions. We have to prove, further, that
variations of all kinds can be increased and accumulated by selection;
and that the struggle for existence to the extent here indicated
actually occurs in nature, and leads to the continued preservation of
favourable variations.

These matters will be discussed in the four succeeding chapters, though
in a somewhat different order--the struggle for existence and the power
of rapid multiplication, which is its cause, occupying the first place,
as comprising those facts which are the most fundamental and those which
can be perfectly explained without any reference to the less generally
understood facts of variation. These chapters will be followed by a
discussion of certain difficulties, and of the vexed question of
hybridity. Then will come a rather full account of the more important of
the complex relations of organisms to each other and to the earth
itself, which are either fully explained or greatly elucidated by the
theory. The concluding chapter will treat of the origin of man and his
relations to the lower animals.

FOOTNOTES:

[Footnote 1: _Geography and Classification of Animals_, p. 350.]

[Footnote 2: These expressions occur in Chapter IX. of the earlier
editions (to the ninth) of the _Principles of Geology_.]

[Footnote 3: L. Agassiz, _Lake Superior_, p. 377.]

CHAPTER II

THE STRUGGLE FOR EXISTENCE

Its importance--The struggle among plants--Among
animals--Illustrative cases--Succession of trees in forests of
Denmark--The struggle for existence on the Pampas--Increase of
organisms in a geometrical ratio--Examples of great powers of
increase of animals--Rapid increase and wide spread of
plants--Great fertility not essential to rapid
increase--Struggle between closely allied species most
severe--The ethical aspect of the struggle for existence.

There is perhaps no phenomenon of nature that is at once so important,
so universal; and so little understood, as the struggle for existence
continually going on among all organised beings. To most persons nature
appears calm, orderly, and peaceful. They see the birds singing in the
trees, the insects hovering over the flowers, the squirrel climbing
among the tree-tops, and all living things in the possession of health
and vigour, and in the enjoyment of a sunny existence. But they do not
see, and hardly ever think of, the means by which this beauty and
harmony and enjoyment is