se.

_Cases showing the Great Powers of Increase of Animals._

As the facts now stated are the very foundation of the theory we are
considering, and the enormous increase and perpetual destruction
continually going on require to be kept ever present in the mind, some
direct evidence of actual cases of increase must be adduced. That even
the larger animals, which breed comparatively slowly, increase
enormously when placed under favourable conditions in new countries, is
shown by the rapid spread of cattle and horses in America. Columbus, in
his second voyage, left a few black cattle at St. Domingo, and these ran
wild and increased so much that, twenty-seven years afterwards, herds of
from 4000 to 8000 head were not uncommon. Cattle were afterwards taken
from this island to Mexico and to other parts of America, and in 1587,
sixty-five years after the conquest of Mexico, the Spaniards exported
64,350 hides from that country and 35,444 from St. Domingo, an
indication of the vast numbers of these animals which must then have
existed there, since those captured and killed could have been only a
small portion of the whole. In the pampas of Buenos Ayres there were, at
the end of the last century, about twelve million cows and three million
horses, besides great numbers in all other parts of America where open
pastures offered suitable conditions. Asses, about fifty years after
their introduction, ran wild and multiplied so amazingly in Quito, that
the Spanish traveller Ulloa describes them as being a nuisance. They
grazed together in great herds, defending themselves with their mouths,
and if a horse strayed among them they all fell upon him and did not
cease biting and kicking till they left him dead. Hogs were turned out
in St. Domingo by Columbus in 1493, and the Spaniards took them to other
places where they settled, the result being, that in about half a
century these animals were found in great numbers over a large part of
America, from 25 deg. north to 40 deg. south latitude. More recently, in New
Zealand, pigs have multiplied so greatly in a wild state as to be a
serious nuisance and injury to agriculture. To give some idea of their
numbers, it is stated that in the province of Nelson there were killed
in twenty months 25,000 wild pigs.[10] Now, in the case of all these
animals, we know that in their native countries, and even in America at
the present time, they do not increase at all in numbers; therefore the
whole