120 CATALOGUE OF THE MAMMALIA OF 
been known to breed together, and to produce fertile offspring, 
which cannot be satisfactorily proved to be the case with the dog 
and the fox, which latter animal some writers consider to be the 
parent-stock of all our races of dogs. 
Besides these arguments, there is, we think, a general ten- 
dency observable in the wild breeds of dogs, or in those which 
have relapsed from civilization to barbarism, to revert more and 
more to the wolfish type. Great as are the diversities between 
many of the races of dogs and the wolf, they are not greater 
than between one race of dogs and another; nor are they of 
themselves sufficient to destroy our belief in this theory, when 
we consider the wonderful effects produced by artificial selection 
on the pigeon and other domesticated animals, as is so graphi- 
cally described by Charles Darwin in his “ Origin of Species.” 
He has, however, we think, failed to show that this modified 
power extends beyond the limits of a true species; and, wherever 
artificial selection has operated, the tendency to revert to the 
parent type is very remarkable. 
The origin and inter-breeding of domesticated animals is, 
however, a question of much difficulty, being governed apparently 
by different laws to those of a feral state, and complicated by 
the influences of artificial and unnatural conditions. 
One of the oldest and purest breeds of dog, the northern sheep 
dog or Colley approaches very nearly in general form and 
character to the wolf, and for this variety the county of North- 
umberland is famous. 
Among the recently discovered remains of the ancient lacus- 
trine habitations of Switzerland—remains co-temporary with 
the stone period of archeologists—have been found bones of 
dogs. These are probably the oldest attainable evidence in 
Europe of the co-existence of the dog with man, and the character 
of the remains may throw some light on the question under dis-. 
cussion. M. Riitimeyer describes the bones as very uniform in 
character, resembling somewhat those of the “jagdhund,” and 
“ wachtelhund,” rough breeds of large size and wolf-like aspect. 
That an animal so thoroughly domesticated, and so faithful 
and true a companion to man would, if neglected, in a very short 
