dless races produced (1200 cabbages).
If we admit selection is steadily at work, and who will doubt it, when
he considers amount of food on an average fixed and reproductive powers
act in geometrical ratio. If we admit that external conditions vary, as
all geology proclaims, they have done and are now doing,--then, if no
law of nature be opposed, there must occasionally be formed races,
[slightly] differing from the parent races. So then any such law{102},
none is known, but in all works it is assumed, in <?> flat contradiction
to all known facts, that the amount of possible variation is soon
acquired. Are not all the most varied species, the oldest domesticated:
who <would> think that horses or corn could be produced? Take dahlia and
potato, who will pretend in 5000 years{103} <that great changes might
not be effected>: perfectly adapted to conditions and then again brought
into varying conditions. Think what has been done in few last years,
look at pigeons, and cattle. With the amount of food man can produce he
may have arrived at limit of fatness or size, or thickness of wool <?>,
but these are the most trivial points, but even in these I conclude it
is impossible to say we know the limit of variation. And therefore with
the [adapting] selecting power of nature, infinitely wise compared to
those of man, <I conclude> that it is impossible to say we know the limit
of races, which would be true <to their> kind; if of different
constitutions would probably be infertile one with another, and which
might be adapted in the most singular and admirable manner, according to
their wants, to external nature and to other surrounding
organisms,--such races would be species. But is there any evidence <that>
species <have> been thus produced, this is a question wholly independent
of all previous points, and which on examination of the kingdom of
nature <we> ought to answer one way or another.

{102} I should interpret this obscure sentence as follows, "No such
opposing law is known, but in all works on the subject a law is (in
flat contradiction to all known facts) assumed to limit the
possible amount of variation." In the _Origin_, the author never
limits the power of variation, as far as I know.

{103} In _Var. under Dom._ Ed. 2, ii. p. 263, the _Dahlia_ is
described as showing sensitiveness to conditions in 1841. All the
varieties of the _Dahlia_ are said to have arisen since 1804
(_i