selected for breeding; and this operation is repeated until the desired
amount of divergence from the primitive stock is reached. It is then found
that by continuing the process of selection--always breeding, that is, from
well-marked forms, and allowing no impure crosses to interfere--a race may
be formed, the tendency of which to reproduce itself is exceedingly strong;
nor is the limit to the amount of divergence which may be thus produced
known; but one thing is certain, that, if certain breeds of dogs, or of
pigeons, or of horses, were known only in a fossil state, no naturalist
would hesitate in regarding them as distinct species.

But in all these cases we have human interference. Without the breeder
there would be no selection, and without the selection no race. Before
admitting the possibility of natural species having originated in any
similar way, it must be proved that there is in Nature some power which
takes the place of man, and performs a selection _sua sponte._ It is
the claim of Mr. Darwin that he professes to have discovered the existence
and the _modus operandi_ of this "natural selection," as he terms it;
and, if he be right, the process is perfectly simple and comprehensible,
and irresistibly deducible from very familiar but well nigh forgotten
facts.

Who, for instance, has duly reflected upon all the consequences of the
marvellous struggle for existence which is daily and hourly going on among
living beings? Not only does every animal live at the expense of some other
animal or plant, but the very plants are at war. The ground is full of
seeds that cannot rise into seedlings; the seedlings rob one another of
air, light and water, the strongest robber winning the day, and
extinguishing his competitors. Year after year, the wild animals with which
man never interferes are, on the average, neither more nor less numerous
than they were; and yet we know that the annual produce of every pair is