AS REGARDS THE FACTORS OF EVOLUTION.

It is admitted by all who are acquainted with the history of biology that
the general idea of organic evolution as expressed in the Doctrine of
Descent was quite familiar to Darwin's grandfather, and to others before
and after him, as we have briefly indicated. It must also be admitted that
some of these pioneers of evolutionism did more than apply the evolution-
idea as a modal formula of becoming, they began to inquire into the factors
in the process. Thus there were pre-Darwinian theories of evolution, and
to these we must now briefly refer. (See Prof. W.A. Locy's "Biology and
its Makers". New York, 1908. Part II. "The Doctrine of Organic
Evolution".

In all biological thinking we have to work with the categories Organism--
Function--Environment, and theories of evolution may be classified in
relation to these. To some it has always seemed that the fundamental fact
is the living organism,--a creative agent, a striving will, a changeful
Proteus, selecting its environment, adjusting itself to it, self-
differentiating and self-adaptive. The necessity of recognising the
importance of the organism is admitted by all Darwinians who start with
inborn variations, but it is open to question whether the whole truth of
what we might call the Goethian position is exhausted in the postulate of
inherent variability.

To others it has always seemed that the emphasis should be laid on
Function,--on use and disuse, on doing and not doing. Practice makes
perfect; c'est a force de forger qu'on devient forgeron. This is one of
the fundamental ideas of Lamarckism; to some extent it met with Darwin's
approval; and it finds many supporters to-day. One of the ablest of these
--Mr Francis Darwin--has recently given strong reasons for combining a