isting causes is the central fact of organic evolution,
as it is of the evolution of mountains and valleys. Seasons change as
the relations which produce them change. But midsummer never gives way
to midwinter in an instant. Nor does the child in an instant become a
man, though in some periods of growth epoch-marking causes may make
development more rapid. Life is conservative. The law of heredity is the
expression of its conservatism. It changes slowly, but it must
constantly change, and all change is by necessity divergence.

There is in nature no single "law of progress," nor is progress in any
group a necessity regardless of conditions. That which we call progress
rests simply on the survival of the better adapted, their survival being
accompanied by their reproduction. Those that live repeat themselves.
The "innate tendency towards progression" of the early evolutionists is
a philosophic myth. Progress and degeneration are alike the resultants
of the various forces at work from generation to generation on and
within a race or species. The same forces which bring progress to a
group under one set of conditions will bring degradation under another.
In their essence the factors of evolution are no more laws of progress
than the attraction of gravitation is. Cosmic order comes from
gravitation. Organic order comes from the factors of evolution.
Evolution is simply orderly change.

_Evolution is not Spontaneous Generation._ There is no necessary
connection between the one theory and the other. Spontaneous generation,
or birth without parentage, on the part of small or useless creatures
was accepted in early times without question. As men began to observe
these animals more carefully, the fact of their spontaneous generation
was doubted. A great step was made when it was found that to screen meat
from flies would protect it from maggots. A greater step came in our own
time when it was proved that to screen infusions from air dust is to
protect them from putrefaction or fermentation. Fermentation is "life
without air." It is the decomposition of sugar by minute creatures who
disintegrate it in their life processes. Putrefaction and decay are also
the same in nature. There is literal truth in Carlyle's statement that
there is still force in a fallen leaf, "else how could it rot?" It is
the force of the minute organisms hidden in the leaf, and whose life is
the leaf's decay. The decay and death of men from contagious diseas