nt agent. Even
putting aside the question whether Nature, acting as she does according
to definite and invariable laws, can be rightly called an unintelligent
agent, such a position as this is wholly untenable. Mix salt and sand,
and it shall puzzle the wisest of men, with his mere natural appliances,
to separate all the grains of sand from all the grains of salt; but a
shower of rain will effect the same object in ten minutes. And so, while
man may find it tax all his intelligence to separate any variety which
arises, and to breed selectively from it, the destructive agencies
incessantly at work in Nature, if they find one variety to be more
soluble in circumstances than the other, will inevitably, in the long
run, eliminate it.

A frequent and a just objection to the Lamarckian hypothesis of the
transmutation of species is based upon the absence of transitional forms
between many species. But against the Darwinian hypothesis this argument
has no force. Indeed, one of the most valuable and suggestive parts of
Mr. Darwin's work is that in which he proves, that the frequent absence
of transitions is a necessary consequence of his doctrine, and that
the stock whence two or more species have sprung, need in no respect be
intermediate between these species. If any two species have arisen from
a common stock in the same way as the carrier and the pouter, say, have
arisen from the rock-pigeon, then the common stock of these two species
need be no more intermediate between the two than the rock-pigeon is
between the carrier and pouter. Clearly appreciate the force of
this analogy, and all the arguments against the origin of species by
selection, based on the absence of transitional forms, fall to the
ground. And Mr. Darwin's position might, we think, have been even
stronger than it is if he had not embarrassed himself with the aphorism,
"Natura non facit saltum," which turns up so often in his pages. We
believe, as we have said above, that Nature does make jumps now and
then, and a recognition of the fact is of no small importance in
disposing of many minor objections to the doctrine of transmutation.

But we must pause. The discussion of Mr. Darwin's arguments in detail
would lead us far beyond the limits within which we proposed, at
starting, to confine this article. Our object has been attained if we
have given an intelligible, however brief, account of the established
facts connected with species, and of the relation of t