now see of the habits of savages, it is probable that the men
of the earlier Stone period--when many great quadrupeds were living which
are now extinct, and when the face of the country was widely different from
what it now is--possessed at least some few domesticated animals, although
their remains have not as yet been discovered. If the science of language
can be trusted, the art of ploughing and sowing the land was followed, and
the chief animals had been already domesticated, at an epoch so immensely
remote, that the Sanskrit, Greek, Latin, Gothic, Celtic, and Sclavonic
languages had not as yet diverged from their common parent-tongue.[598]

{244}

It is scarcely possible to overrate the effects of selection occasionally
carried on in various ways and places during thousands of generations. All
that we know, and, in a still stronger degree, all that we do not
know,[599] of the history of the great majority of our breeds, even of our
more modern breeds, agrees with the view that their production, through the
action of unconscious and methodical selection, has been almost insensibly
slow. When a man attends rather more closely than is usual to the breeding
of his animals, he is almost sure to improve them to a slight extent. They
are in consequence valued in his immediate neighbourhood, and are bred by
others; and their characteristic features, whatever these may be, will then
slowly but steadily be increased, sometimes by methodical and almost always
by unconscious selection. At last a strain, deserving to be called a
sub-variety, becomes a little more widely known, receives a local name, and
spreads. The spreading will have been extremely slow during ancient and
less civilised times, but now is rapid. By the time that the new breed had
assumed a somewhat distinct character, its history, hardly noticed at the
time, will have been completely forgotten; for, as Low remarks,[600] "we
know how quickly the memory of such events is effaced."

As soon as a new breed is thus formed, it is liable through the same
process to break up into new strains and sub-varieties. For different
varieties are suited for, and are valued under, different circumstances.
Fashion changes, but, should a fashion last for even a moderate length of
time, so strong is the principle of inheritance, that some effect will
probably be impressed on the breed. Thus varieties go on increasing in
number, and history shows us how wonderfully they have increa