election and sexual
selection has reference only to the requirements or the tastes of the
organisms themselves. But, with the exception of this one point of
difference, the processes and the products are identical in kind.
Persevering selection by man is thus proved to be capable of creating
what are virtually new specific types, and this in any required
direction. Hence, when we remember how severe is the struggle for
existence in nature, it becomes impossible to doubt that selection by
nature is able to do at least as much as artificial selection in the way
of thus creating new types out of old ones. Artificial selection,
indeed, notwithstanding the many and marvellous results which it has
accomplished, can only be regarded as but a feeble imitation of natural
selection, which must act with so much greater vigilance and through
such immensely greater periods of time. In a word, the proved
capabilities of artificial selection furnish, in its best conceivable
form, what is called an argument _a fortiori_ in favour of natural
selection.

Or, to put it in another way, it may be said that for thousands of years
mankind has been engaged in making a gigantic experiment to test, as it
were by anticipation, the theory of natural selection. For, although
this prolonged experiment has been carried on without any such intention
on the part of the experimenters, it is none the less an experiment in
the sense that its results now furnish an overwhelming verification of
Mr. Darwin's theory. That is to say, they furnish overwhelming proof of
the efficacy of the selective principle in the modification of organic
types, when once this principle is brought steadily and continuously to
bear upon a sufficiently long series of generations.

In order to furnish ocular evidence of the value of this line of
verification, I have had the following series of drawings prepared.
Another and equally striking series might be made of the products of
artificial selection in the case of plants; but it seems to me that the
case of animals is more than sufficient for the purpose just stated.
Perhaps it is desirable to add that considerable care has been bestowed
upon the execution of these portraits; and that in every case the latter
have been taken from the most typical specimens of the artificial
variety depicted. Those of them which have not been drawn directly from
life are taken from the most authoritative sources; and, before being
submitted to t