The Descent of Man

elephant, the slowest breeder of all known
animals, would in a few thousand years stock
the whole world. The increase of every species
of monkey must be checked by some means;
but not, as Brehm remarks, by the attacks of
beasts of prey. No one will assume that the actual
power of reproduction in the wild horses
and cattle of America, was at first in any sensible
degree increased; or that, as each district
became fully stocked, this same power was
diminished. No doubt, in this case, and in all
others, many checks concur, and different
checks under different circumstances; periodical
dearths, depending on unfavourable seasons,
being probably the most important of all.
So it will have been with the early progenitors
of man.
NATURAL SELECTION.
We have now seen that man is variable in body
and mind; and that the variations are induced,