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184 HERBERT SPENCER

especially from facts of breeding and cultivation, that
these mutations, rather than the minute ^(e fluctuating "
variations, have supplied the raw material on which
selection has chiefly operated in the evolution of
species.

It also becomes more and more evident that the
living creature may vary as a unity, so that if there is
more of one character there is less of another, and so
that one change brings another in its train. It seems
as if the organism as a whole—through its germinal
organisation, of course—may suddenly pass from one
position of organic equilibrium to another. Thus we
are not shut up to the assumption of the piecemeal
variation of minute parts; there is greater definiteness
and less fortuitousness in variation than was previously
supposed. We begin, from actual data, to see the
truth of the view which Goethe and Nageli suggested,
that the evolution of organisms is pre-eminently a
story of self-differentiating and self-integrating
growth,—cumulative, selective, definite, and har-
monious—like crystallisation. As to the origin of varia-
tions, it must be admitted that until we know the
actual facts better, we cannot expect to know much in
regard to their antecedents. Many suggestions have
been made, some of which may be summarised.

There is something comparable to the First Law of
Motion to be read out of the persistence of character-
istics from generation to generation. Like tends to
beget like. But while the relation of genetic con-
tinuity which links generation to generation tends to
ensure this persistence, it presents no more than a
curb to the occurrence of variation. "While complete
and perfect inheritance and complete and perfect ex-



	184 HERBERT SPENCER especially from facts of breeding and cultivation, that these mutations, rather than the minute ^(e fluctuating " variations, have supplied the raw material on which selection has chiefly operated in the evolution of species. It also becomes more and more evident that the living creature may vary as a unity, so that if there is more of one character there is less of another, and so that one change brings another in its train. It seems as if the organism as a whole—through its germinal organisation, of course—may suddenly pass from one position of organic equilibrium to another. Thus we are not shut up to the assumption of the piecemeal variation of minute parts; there is greater definiteness and less fortuitousness in variation than was previously supposed. We begin, from actual data, to see the truth of the view which Goethe and Nageli suggested, that the evolution of organisms is pre-eminently a story of self-differentiating and self-integrating growth,—cumulative, selective, definite, and har- monious—like crystallisation. As to the origin of varia- tions, it must be admitted that until we know the actual facts better, we cannot expect to know much in regard to their antecedents. Many suggestions have been made, some of which may be summarised. There is something comparable to the First Law of Motion to be read out of the persistence of character- istics from generation to generation. Like tends to beget like. But while the relation of genetic con- tinuity which links generation to generation tends to ensure this persistence, it presents no more than a curb to the occurrence of variation. "While complete and perfect inheritance and complete and perfect ex-