egg cell and the sperm
cell fuse together. There are as many possibilities now as there were
in either parent, but not all the potentialities of both parents. Half
the possibilities of each have been thrown away, and hence cannot
appear in the offspring. By this constant process we get, in every
generation, new combinations of qualities. This is the main cause,
says Weissman, for variations.

There is, however, another possible cause. Each cell has enough
determinants in it for many individuals, and it seems to be more or
less a matter of accident which qualities shall come out. It has been
suggested that as an egg lies within the gland, a blood vessel may
bring blood to it in such way that a determinant, lying in a certain
position in the egg, may get the richest supply of blood, and hence
develop at the expense of the less nourished determinant. By these two
methods variation comes into an animal's life, if Weissman and his
school are to be believed.

This is a serious blow, if true, to many theories of evolution. The
great mass of evolutionists still feel that somehow there is an
influence by which the environment produces variation. How the
influences of the surrounding world can get down into the body of the
parent and affect the egg is unknown. This is freely confessed by
every biologist. All are agreed that Weissman's work has made us
cautious, and prevented our lightly accepting a belief in the
influence of the environment. Yet it is felt by many that slowly and
gradually, in the long run, the germ is affected in the same manner as
is the body of the parent. In other words, even those who are not
followers of Weissman, have accepted the idea that there is little
inheritance of acquired characters. Yet they return to the belief that
somehow, in some way as yet unexplainable, the main cause for
variation in animals lies in the situation in which they live, and
tends toward better adaptation to that situation.

Whether men with this conviction are merely reactionaries whose
confidence is returning, or bold thinkers whose views will ultimately
prevail, time alone can tell.

A second strong objection was brought against the theory of Natural
Selection. Darwin declared that small variations in favorable
directions are selected and become the starting point of new and
better things. It is soon seen, however, that the effect of unaided
Natural Selection would be but to mix new departures with the old
forms, and so