savage who had a little more musical
perception than the rest, would derive any such advantage in the
maintenance of life as would secure the spread of his superiority by
inheritance of the variation. And then what are we to say of harmony? We
cannot suppose that the appreciation of this, which is relatively
modern, can have arisen by descent from the men in whom successive
variations increased the appreciation of it--the composers and musical
performers; for on the whole, these have been men whose worldly
prosperity was not such as enabled them to rear many children inheriting
their special traits. Even if we count the illegitimate ones, the
survivors of these added to the survivors of the legitimate ones, can
hardly be held to have yielded more than average numbers of descendants;
and those who inherited their special traits have not often been thereby
so aided in the struggle for existence as to further the spread of such
traits. Rather the tendency seems to have been the reverse.

Since the above passage was written, I have found in the second volume
of _Animals and Plants under Domestication_, a remark made by Mr.
Darwin, practically implying that among creatures which depend for their
lives on the efficiency of numerous powers, the increase of any one by
the natural selection of a variation is necessarily difficult. Here it
is.

"Finally, as indefinite and almost illimitable variability is the
usual result of domestication and cultivation, with the same part
or organ varying in different individuals in different or even in
directly opposite ways; and as the same variation, if strongly
pronounced, usually recurs only after long intervals of time, any
particular variation would generally be lost by crossing,
reversion, and the accidental destruction of the varying
individuals, unless carefully preserved by man."--Vol. ii, 292.

Remembering that mankind, subject as they are to this domestication and
cultivation, are not, like domesticated animals, under an agency which
picks out and preserves particular variations; it results that there
must usually be among them, under the influence of natural selection
alone, a continual disappearance of any useful variations of particular
faculties which may arise. Only in cases of variations which are
specially preservative, as for example, great cunning during a
relatively barbarous state, can we expect increase from natural
selection a