air, what becomes of the heritage from the father who may
have brown eyes and dark hair? Whatever may happen to the children,
there is always an excuse, only an excuse is not an explanation. If
the daughter of a beautiful woman grows up very plain, the Frenchman
was no doubt right when he remarked, _C'etait alors le pere qui
n'etait pas bien_, and if the son of a teetotaller should later in
life become a drunkard, the conclusion would be even worse. In fact,
this kind of atavistic or parental influence is a very pleasant
subject for gossips, but from a scientific point of view, it is
perfectly futile. If it is not the father, it is the mother; if it is
not the grandmother, it is the grandfather; in fact, family influences
can always be traced to some source or other, if the whole pedigree
may be dug up and ransacked. But for that very reason they are of no
scientific value whatever. They can neither be accounted for, nor can
they be used to account for anything themselves. Even of twins, though
very like each other in many respects, one may be phlegmatic, the
other passionate. Some scientists, such as Weismann and others, have
therefore denied, and I believe rightly, that any acquired characters,
whether physical or mental, can ever be inherited by children from
their parents. Whatever similarity there is, and there is plenty, is
traced back by him to what he calls the germ-plasm, working on
continuously in spite of all individual changes. If that germ-plasm is
liable to certain peculiar modifications in the father or grandfather,
it is liable to the same or similar modifications in the offspring,
that is, if the father could become a drunkard, so could the son, only
we must not think that the _post hoc_ is here the same as the _propter
hoc_. If we compare the germ-plasm to the molecules constituting the
stem or branches of a vine, its grapes and leaves in their similarity
and their variety would be comparable to the individuals belonging to
the same family, and springing from the same family tree. But then the
grape we see would not be what the grape of last year, or the grape
immediately preceding it on the same branch, had made it, though there
can be no doubt that the antecedent possibilities of the new grape
were the same as those of the last. If one grape is blue, the next
will be blue too, but no one would say that it was blue because the
last grape was blue. The real cause would be that the molecules of the
proto