ore of improvements as regards either species.

The guinea-fowl is excused, as being "no general favourite, and scarcely
more common than the peacock;" but Mr. Darwin himself shows and admits that
it is a noteworthy instance of constancy under very varied conditions.

These instances alone (and there are yet others) seem sufficient to
establish the assertion, that degree of change is different in different
domestic animals. It is, then, somewhat unwarrantable in any Darwinian to
assume that _all_ wild animals have a capacity for change similar to that
existing in _some_ of the domestic ones. It seems more reasonable to assert
the opposite, namely, that if, as Mr. Darwin says, the capacity for change
is different in different domestic animals, it must surely be limited in
those which have it least, and _a fortiori_ limited in wild animals.

Indeed, it cannot be reasonably maintained that wild species certainly vary
as much as do domestic races; it is possible that they may do so, but at
least this has not been yet shown. Indeed, the much greater degree of
variation amongst domestic animals than amongst wild ones is asserted over
and over again by Mr. Darwin, and his assertions are supported by an
overwhelming mass of facts and instances.

Of course, it may be asserted that a tendency to indefinite change exists
in all cases, and that it is only the circumstances and conditions of {121}
life which modify the effects of this tendency to change so as to produce
such different results in different cases. But assertion is not proof, and
this assertion has not been proved. Indeed, it may be equally asserted (and
the statement is more consonant with some of the facts given), that
domestication in certain animals induces and occasions a capacity for
change which is wanting in wild animals--the introduction of new causes
occasioning new effects. For, though a certain degree of variability
(normally, in all probability, only oscillation) exists in all organisms,
yet domestic ones are exposed to new and different causes of variability,
resulting in such striking divergencies as have been observed. Not even in
this latter case, however, is it necessary to believe that the variability
is indefinite, but only that the small oscillations become in certain
instances intensified into large and conspicuous ones. Moreover, it is
possible that some of our domestic animals have been in part chosen and
domesticated through possessing variabi