ices by which we are
able to carry back the history of other domesticated animals to their
primitive or even extinct ancestry, fail in the case of the dog. When
the stock is allowed to go as nearly wild as they can be induced to
become, we do not find that they thereby approach to any known wild
form. It therefore seems reasonable to betake ourselves to another
basis for the natural history of the dog, which has not yet been made a
matter of much inquiry, but which promises to afford us more substantial
truth than the conjectures which we have just considered.

We should, in the first place, note the fact that the ancestors of our
more important domesticated animals, those which have been longest in
subjugation, have commonly disappeared from the wild state--the species,
except for the cultivated forms, having gone into the irrecoverable
past. This is the case with the wild kindred of our bulls, horses,
sheep, and camels, there probably being none of the original wild
species of these groups now living, except those which have been more
or less completely subjugated by man, and then have returned to the
wilderness. The fact is, that with any large mammal the domestication
of the species tends to bring about the destruction of the remaining
wild forms. If we go back in fancy to the time when the dog was taken
in from the wilderness, we readily perceive how certainly the
subjugated individuals would have mingled with their wild kindred, so
that either the wild would have become tame or _vice versa_. The same
incompatibility which exists between slavery and freedom in our own
species in any given territory may be said to hold in the case of
captive animals. It is particularly on this account that I am disposed
to think that our races of dogs have been derived from one or more
original species of truly canine ancestors, the wild forms of which
have long since disappeared from the earth.

[Illustration: St. Bernard]

Although there are no species of wild dogs now in existence to which we
can refer the origin of our household friends, there are several known
to us only in their fossil state, from which they may possibly--indeed,
we may say probably--have been derived. These creatures are, of course,
represented only by their skeletons, and even these remains have only
been found in an imperfect state of preservation. It is evident,
however, that these extinct species, or at least certain of them, lived
down to the time whe