authors go so far as to assert that every chief domestic breed must have
had its wild prototype. This latter view is extremely improbable: it allows
nothing for variation; it passes over the almost monstrous character of
some of the breeds; and it almost necessarily assumes that a large number
of species have become extinct since man domesticated the dog; whereas we
plainly see that wild members of the dog-family are extirpated by human
agency with much difficulty; even so recently as 1710 the wolf existed in
so small an island as Ireland.

The reasons which have led various authors to infer that our dogs have
descended from more than one wild species are as follows. (1/2. Pallas, I
believe, originated this doctrine in 'Act. Acad. St. Petersburgh' 1780 Part
2. Ehrenberg has advocated it, as may be seen in De Blainville's
'Osteographie' page 79. It has been carried to an extreme extent by Col.
Hamilton Smith in the 'Naturalist Library' volumes 9 and 10. Mr. W.C.
Martin adopts it in his excellent 'History of the Dog' 1845; as does Dr.
Morton, as well as Nott and Gliddon, in the United States. Prof. Low, in
his 'Domesticated Animals' 1845 page 666, comes to this same conclusion. No
one has argued on this side with more clearness and force than the late
James Wilson, of Edinburgh, in various papers read before the Highland
Agricultural and Wernerian Societies. Isidore Geoffroy Saint-Hilaire
('Hist. Nat. Gen.' 1860 tome 3 page 107), though he believes that most dogs
have descended from the jackal, yet inclines to the belief that some are
descended from the wolf. Prof. Gervais ('Hist. Nat. Mamm.' 1855 tome 2 page
69, referring to the view that all the domestic races are the modified
descendants of a single species, after a long discussion, says, "Cette
opinion est, suivant nous du moins, la moins probable.") Firstly, the great
difference between the several breeds; but this will appear of
comparatively little weight, after we shall have seen how great are the
differences between the several races of various domesticated animals which