ardinal
importance to the inner brotherhood of evolutionism, he did not
anticipate his more famous successor. He thought organic evolution was
wholly due to the direct action of surrounding circumstances, to the
intercrossing of existing forms, and above all to the actual efforts of
animals themselves. In other words, he had not discovered natural
selection, the cardinal idea of Charles Darwin's epoch-making book. For
him, the giraffe had acquired its long neck by constant reaching up to
the boughs of trees; the monkey had acquired its opposable thumb by
constant grasping at the neighbouring branches; and the serpent had
acquired its sinuous shape by constant wriggling through the grass of
the meadows. Charles Darwin improved upon all that by his suggestive
hint of survival of the fittest, and in so far, but in so far alone, he
became the real father of modern biological evolutionism.

From the days of Lamarck, to the day when Charles Darwin himself
published his wonderful 'Origin of Species,' this idea that plants and
animals might really have grown, instead of having been made all of a
piece, kept brewing everywhere in the minds and brains of scientific
thinkers. The notions which to the outside public were startlingly new
when Darwin's book took the world by storm, were old indeed to the
thinkers and workers who had long been familiar with the principle of
descent with modification and the speculations of the Lichfield doctor
or the Paris philosopher. Long before Darwin wrote his great work,
Herbert Spencer had put forth in plain language every idea which the
drawing-room biologists attributed to Darwin. The supporters of the
development hypothesis, he said seven years earlier--yes, he called it
the 'development hypothesis' in so many words--'can show that
modification has effected and is effecting great changes in all
organisms, subject to modifying influences.' They can show, he goes on
(if I may venture to condense so great a thinker), that any existing
plant or animal, placed under new conditions, begins to undergo adaptive
changes of form and structure; that in successive generations these
changes continue, till the plant or animal acquires totally new habits;
that in cultivated plants and domesticated animals changes of the sort
habitually occur; that the differences thus caused, as for example in
dogs, are often greater than those on which species in the wild state
are founded, and that throughout all organic