their age cannot be positively determined.

The existence of a single race, remarkably constant in form during the
whole Neolithic period, is an interesting fact in contrast with what we see
of the changes which the races underwent during the period of the
successive Egyptian monuments, and in contrast with our existing dogs. The
character of this animal during the Neolithic period, as given by
Rutimeyer, supports De Blainville's view that our varieties have descended
from an unknown and extinct form. But we should not forget that we know
nothing with respect to the antiquity of man in the warmer parts of the
world. The succession of the different kinds of dogs in Switzerland and
Denmark is thought to be due to the immigration of conquering tribes
bringing with them their dogs; and this view accords with the belief that
different wild canine animals were domesticated in different regions.
Independently of the immigration of new races of man, we know from the
wide-spread presence of bronze, composed of an alloy of tin, how much
commerce there must have been throughout Europe at an extremely remote
period, and dogs would then probably have been bartered. At the present
time, amongst the savages of the interior of Guiana, the Taruma Indians are
considered the best trainers of dogs, and possess a large breed which they
barter at a high price with other tribes. (1/11. Sir R. Schomburgk has
given me information on this head. See also 'Journal of R. Geographical
Soc.' volume 13 1843 page 65.)

The main argument in favour of the several breeds of the dog being the
descendants of distinct wild stocks, is their resemblance in various
countries to distinct species still existing there. It must, however, be
admitted that the comparison between the wild and domesticated animal has
been made but in few cases with sufficient exactness. Before entering on
details, it will be well to show that there is no a priori difficulty in