the practiced eye from the rest
of the group. When they were planted and crossed with each other, and
the resulting seeds were again planted, the peculiarity remained
constant in all the members of the collection. Here then we have a
true variation, not large in amount, but at the same time quite
definite, and which from the first remains true. Here are the
beginnings, says DeVries, of new species. They are true from the
first; they can live among other members of the species and still come
true; they do not need isolation, at least in Wagner's geographical
sense. These forms DeVries calls mutations. It is his thought that a
species may run along uniformly for a long time when, from some cause
which he has not determined as yet, instability comes into the species
and it varies in quite a number of directions. Each of these
variations may be the starting point of a new species. DeVries
believes that he has at least half a dozen mutants of his new Evening
Primrose.

This theory of Mutation has been eagerly seized upon by many
botanists. The zooelogists have not accepted it quite so
enthusiastically. If this is the chief method by which species
transform, it seems strange that we do not find more mutations than we
do. Perhaps we do not look carefully enough; perhaps we shall find
them a little later. Just at present it seems premature to believe
that all evolution is by mutation, although quite possibly some of it
is. The main apparent advantage of mutation is that it hastens the
time in which a new species may arise.

There are certain difficulties which run back into the problem, and
which must first be reasonably solved before a clear understanding of
the idea of evolution is possible. The first of these is as to the
nature of life. What is life? The reply of the biologist will probably
be that so far as its material side is concerned, it must be answered
in terms of physics and chemistry. As to any side not material, if it
have any such side, science says that the chemist can have nothing to
say. The chemist may have an opinion of his own based on some other
ground than his chemistry, but so far as he is a chemist, he has no
opinion. The chemical side of life is being very carefully and very
fully investigated. We are certainly being brought nearer to the
borders of the living substance. We are rapidly gaining fuller
knowledge of the physical and chemical processes which constitute
life, or with which life is always