c beings as is the mistletoe, whose existence absolutely depends
on certain insects for impregnation, certain birds for transportal, and
certain trees for growth. Furthermore, if the insect which had been
induced regularly to visit this hypothetical plant profited much by it,
our same Being might wish by selection to modify by gradual selection
the insect's structure, so as to facilitate its obtaining the honey or
pollen: in this manner he might adapt the insect (always presupposing
its organization to be in some degree plastic) to the flower, and the
impregnation of the flower to the insect; as is the case with many bees
and many plants.

{225} The mistletoe is used as an illustration in _Origin_, Ed. i.
p. 3, vi. p. 3, but with less detail.

Seeing what blind capricious man has actually effected by selection
during the few last years, and what in a ruder state he has probably
effected without any systematic plan during the last few thousand years,
he will be a bold person who will positively put limits to what the
supposed Being could effect during whole geological periods. In
accordance with the plan by which this universe seems governed by the
Creator, let us consider whether there exists any _secondary_ means in
the economy of nature by which the process of selection could go on
adapting, nicely and wonderfully, organisms, if in ever so small a
degree plastic, to diverse ends. I believe such secondary means do
exist{226}.

{226} <Note in original.> The selection, in cases where adult lives
only few hours as Ephemera, must fall on larva--curious speculation
of the effect <which> changes in it would bring in parent.

_Natural means of Selection{227}._

{227} This section forms part of the joint paper by Darwin and
Wallace read before the Linnean Society on July 1, 1858.

De Candolle, in an eloquent passage, has declared that all nature is at
war, one organism with another, or with external nature. Seeing the
contented face of nature, this may at first be well doubted; but
reflection will inevitably prove it is too true. The war, however, is
not constant, but only recurrent in a slight degree at short periods and
more severely at occasional more distant periods; and hence its effects
are easily overlooked. It is the doctrine of Malthus applied in most
cases with ten-fold force. As in every climate there are seasons for
each of its inhabitants of greater and less abundance, so