up the vacancies caused by senile decay. As the field of existence
is limited and preoccupied, it is only the hardier, more robust,
better suited to circumstance individuals, who are able to struggle
forward to maturity, these inhabiting only the situations to which
they have superior adaptation and greater power of occupancy than
any other kind; the weaker and less circumstance-suited being
prematurely destroyed. This principle is in constant action; it
regulates the colour, the figure, the capacities, and instincts;
those individuals in each species whose colour and covering are best
suited to concealment or protection from enemies, or defence from
inclemencies or vicissitudes of climate, whose figure is best
accommodated to health, strength, defence, and support; whose
capacities and instincts can best regulate the physical energies to
self-advantage according to circumstances--in such immense waste of
primary and youthful life those only come forward to maturity from
THE STRICT ORDEAL BY WHICH NATURE TESTS THEIR ADAPTATION TO HER
STANDARD OF PERFECTION and fitness to continue their kind by
reproduction." {86a} A little lower down Mr. Matthew speaks of
animals under domestication "NOT HAVING UNDERGONE SELECTION BY THE
LAW OF NATURE, OF WHICH WE HAVE SPOKEN, and hence being unable to
maintain their ground without culture and protection."

The distinction between Darwinism and Neo-Darwinism is generally
believed to lie in the adoption of a theory of natural selection by
the younger Darwin and its non-adoption by the elder. This is true
in so far as that the elder Darwin does not use the words "natural
selection," while the younger does, but it is not true otherwise.
Both writers agree that offspring tends to inherit modifications
that have been effected, from whatever cause, in parents; both hold
that the best adapted to their surroundings live longest and leave