nly by howls.
But the difficulty here is not so great as it seems, since we know
that jackals, wild dogs, and wolf pups reared by bitches readily
acquire the habit. On the other hand, domestic dogs allowed to run
wild forget how to bark, while there are some which have not yet
learned so to express themselves.

The presence or absence of the habit of barking cannot, then, be
regarded as an argument in deciding the question concerning the origin
of the dog. This stumbling block consequently disappears, leaving
us in the position of agreeing with Darwin, whose final hypothesis
was that "it is highly probable that the domestic dogs of the world
have descended from two good species of wolf (_C. lupus_ and
_C. latrans_), and from two or three other doubtful species of
wolves--namely, the European, Indian, and North African forms; from
at least one or two South American canine species; from several races
or species of jackal; and perhaps from one or more extinct species";
and that the blood of these, in some cases mingled together, flows
in the veins of our domestic breeds.

CHAPTER II

THE ENGLISH MASTIFF

Of the many different kinds of dogs now established as British, not
a few have had their origin in other lands, whence specimens have
been imported into this country, in course of time to be so improved
by selection that they have come to be commonly accepted as native
breeds. Some are protected from the claim that they are indigenous
by the fact that their origin is indicated in their names. No one
would pretend that the St. Bernard or the Newfoundland, the Spaniel
or the Dalmatian, are of native breed. They are alien immigrants whom
we have naturalised, as we are naturalising the majestic Great Dane,
the decorative Borzoi, the alert Schipperke, and the frowning Chow
Chow, which are of such recent introduction that they must still be
regarded as half-acclimatised foreigners. But of the antiquity of
the Mastiff there can be no doubt. He is the oldest of our British
dogs, cultivated in these islands for so many centuries that the only
difficulty concerning his history is that of tracing his descent,
and discovering the period when he was not familiarly known.

It is possible that the Mastiff owes his origin to some remote
ancestor of alien strain. The Assyrian kings possessed a large dog
of decided Mastiff type, and used it in the hunting of lions. It is
supposed by many students that the breed was introduced