as the
"first-steps" in the evolutionary process. For, this conception
distinguishes Darwinism from the more recent evolutionary theory, e.g.,
of De Vries who rejects the notion that species have originated by the
accumulation of fluctuating variations; and it is quite as essential to
the Darwinian theory of natural selection as is the "struggle for
life." It is, in fact, an integral element in the selection theory.

The attitude of science towards Darwinism may, therefore, be
conveniently summarized in its answer to the following questions:

1. Is there any evidence that such a struggle for life among mature
forms, as Darwin postulates, actually occurs?

2. Can the origin of adaptive structures be explained on the ground of
their _utility_ in this struggle, i.e., is it certain or even
probable that the organism would have perished, had it lacked the
particular adaptation in its present degree of perfection? On the
contrary, is there not convincing proof that many, and presumably most,
adaptations cannot be thus accounted for?

The above questions are concerned with "the struggle for life." Those
which follow have to do with the problem of variations.

3. Is there any reason to believe that new species may originate by the
accumulation of fluctuating individual variations?

4. Does the evidence of the geological record--which, as Huxley
observed, is the only direct evidence that can be had in the question
of evolution--does this evidence tell for or against the origin of
existing species from earlier ones by means of minute gradual
modifications?

We must be content here with the briefest outline of the reply of
science to these inquiries.

1. Darwin invites his readers to "keep steadily in mind that each
organic being is striving to increase in geometrical ratio." If this
tendency were to continue unchecked, the progeny of living beings would
soon be unable to find standing room. Indeed, the very bacteria would
quickly convert every vestige of organic matter on earth into their own
substance. For has not Cohn estimated that the offspring of a single
bacterium, at its ordinary rate of increase under favorable conditions,
would in three days amount to 4,772 billions of individuals with an
aggregate weight of seven thousand five hundred tons? And the
19,000,000 elephants which, according to Darwin, should to-day
perpetuate the lives of each pair that mated in the twelfth
century--surely these would be a "magna