guinea-fowl, asparagus, Jerusalem artichoke{215}. I have already said
that probably different species, like different sub-varieties, possess
different degrees of tendency to vary; but I am inclined to attribute in
these cases the want of numerous races less to want of variability than
to selection not having been practised on them. No one will take the
pains to select without some corresponding object, either of use or
amusement; the individuals raised must be tolerably numerous, and not so
precious, but that he may freely destroy those not answering to his
wishes. If guinea-fowls or peacocks{216} became "fancy" birds, I cannot
doubt that after some generations several breeds would be raised. Asses
have not been worked on from mere neglect; but they differ in _some_
degree in different countries. The insensible selection, due to
different races of mankind preserving those individuals most useful to
them in their different circumstances, will apply only to the oldest and
most widely domesticated animals. In the case of plants, we must put
entirely out of the case those exclusively (or almost so) propagated by
cuttings, layers or tubers, such as the Jerusalem artichoke and laurel;
and if we put on one side plants of little ornament or use, and those
which are used at so early a period of their growth that no especial
characters signify, as asparagus{217} and seakale, I can think of none
long cultivated which have not varied. In no case ought we to expect to
find as much variation in a race when it alone has been formed, as when
several have been formed, for their crossing and recrossing will
greatly increase their variability.

{215} See _Origin_, Ed. i. p. 42, vi. p. 48.

{216} <Note in the original.> There are white peacocks.

{217} <Note in the original.> There are varieties of asparagus.

_Summary of first Chapter._

To sum up this chapter. Races are made under domestication: 1st, by the
direct effects of the external conditions to which the species is
exposed: 2nd, by the indirect effects of the exposure to new conditions,
often aided by excess of food, rendering the organization plastic, and
by man's selecting and separately breeding certain individuals, or
introducing to his stock selected males, or often preserving with care
the life of the individuals best adapted to his purposes: 3rd, by
crossing and recrossing races already made, and selecting their
offspring. After some generations man may