rganism taken conjointly with the
changes of geology, which are steadily (and sometimes suddenly, as when
an isthmus at last separates) in progress, that occasionally organisms
must suddenly be introduced into new regions, where, if the conditions
of existence are not so foreign as to cause its extermination, it will
often be propagated under circumstances still more closely analogous to
those of domestication; and therefore we expect will evince a tendency
to vary. It appears to me quite _inexplicable_ if this has never
happened; but it can happen very rarely. Let us then suppose that an
organism by some chance (which might be hardly repeated in 1000 years)
arrives at a modern volcanic island in process of formation and not
fully stocked with the most appropriate organisms; the new organism
might readily gain a footing, although the external conditions were
considerably different from its native ones. The effect of this we might
expect would influence in some small degree the size, colour, nature of
covering &c., and from inexplicable influences even special parts and
organs of the body. But we might further (and <this> is far more important)
expect that the reproductive system would be affected, as under
domesticity, and the structure of the offspring rendered in some degree
plastic. Hence almost every part of the body would tend to vary from the
typical form in slight degrees, and in no determinate way, and therefore
_without selection_ the free crossing of these small variations
(together with the tendency to reversion to the original form) would
constantly be counteracting this unsettling effect of the extraneous
conditions on the reproductive system. Such, I conceive, would be the
unimportant result without selection. And here I must observe that the
foregoing remarks are equally applicable to that small and admitted
amount of variation which has been observed in some organisms in a state
of nature; as well as to the above hypothetical variation consequent on
changes of condition.

Let us now suppose a Being{224} with penetration sufficient to perceive
differences in the outer and innermost organization quite imperceptible
to man, and with forethought extending over future centuries to watch
with unerring care and select for any object the offspring of an
organism produced under the foregoing circumstances; I can see no
conceivable reason why he could not form a new race (or several were he
to separate the stock o