104 INTRODUCTION. 
other laws, whose periods of operation we are not 
competent to measure. 
Without, therefore, recapitulating the various 
arguments adduced in the foregoing pages, we are 
inclined to believe there are sufficient data to doubt 
the opinion that the different races of domestic 
dogs are all sprung from one species, and still more 
that the wolf (Canis lupus, Linn.) was the sole 
parent in question ; on the contrary, we are inclined 
to lean, for the present, to the conjecture that seve- 
ral species, aborigine, constructed with faculties to 
intermix, including the wolf, the buansu, the anthus, 
the dingo, and the jackal, were parents of domestic 
dogs. That even the dhole, or a thous, may have 
been progenitors of the greyhound races; and that 
a lost or undiscovered species, allied to Canis tricolor 
or Hyena venatica of Burchell, was the source of 
the short muzzled and strong jawed races of primi- 
tive mastiffs. 
Whatever may be thought of this opinion, thus 
much at least is certain, that the advances towards 
forming hybrid races are always made by the domes- 
tic species to the wild ; and that when thus obtained, 
if kept to itself, and the cross breed gradually be- 
come sterile, it does not prevent repeated intermix- 
ture of one or the other, and therefore the admission 
of a great proportion of alien blood, which may 
again be crossed upon by the admission of hybrids 
from another source, whether it be wolf, jackal, 
pahariah, or dingo; and that experiments, in the 
form they have been hitherto made, in a different 
