earing; for
instance the vermiform appendix of the intestine and the pineal gland
of the brain. These rudiments often persist for still a longer time in
the embryo, as we have seen in the case of the ancestral teeth of the
embryo whales. We also meet with the stumps of wings in the chrysalis
of certain ants (_Anergates_), the males of which have lost their
wings.

=Natural Selection.=--The artificial selection practiced by gardeners
and cattle breeders led _Darwin_ to his hypothesis of natural
selection by the struggle for existence. Confirmed in his idea by the
observation of tropical nature, _Darwin_ thought he could explain the
origin of living beings by natural selection. It is this hypothesis
which is properly called _Darwinism_. But the name Darwinism has also
been given to evolution as a whole, which has been the cause of
endless confusion. All the mystic and narrow-minded, full of biblical
prejudice, naturally profit by this confusion to attack the facts of
evolution and science itself.

=The Struggle for Existence.=--The struggle for existence and natural
selection are absolutely positive facts, which can be constantly
verified by the observation of living nature as it is presented to us.
All living beings eat one another or at any rate struggle against each
other, plants as well as animals; and, apart from air and water,
animals are almost entirely nourished by plants and other animals. It
is obvious that in this perpetual struggle the less adapted and the
less armed--and by arms we include the powers of reproduction,
resistance to diseases and to cold, etc.--disappear, while the better
adapted and the better armed persist. I confess I cannot understand
the detractors of _Darwin_ who are blind in face of these facts and
hypnotized by certain conventional suggestions.

On the other hand, what always has been and still remains hypothetical
is the explanation of the descent of all plants and animals by natural
selection alone. We have already spoken of the _mutations_ of _de
Vries_, and the theory of the _mneme_ elaborated by _Semon_, and need
not repeat them here. Thanks to the idea of _Hering_, worked out by
_Semon_, the facts are now explained in a satisfactory manner.
Engraphia, produced in the organisms by the irritating agents of the
external world, prepares and builds up little by little their
increasing complications, while selection, by continually eliminating
the unfit, directs the elaborating work