The Descent of Man

the same homological plan as that of other
mammals. He passes through the same phases
of embryological development. He retains many
rudimentary and useless structures, which
no doubt were once serviceable. Characters
occasionally make their re-appearance in him,
which we have reason to believe were possessed
by his early progenitors. If the origin of
man had been wholly different from that of all
other animals, these various appearances
would be mere empty deceptions; but such an
admission is incredible. These appearances, on
the other hand, are intelligible, at least to a large
extent, if man is the co-descendant with other
mammals of some unknown and lower
form.
Some naturalists, from being deeply impressed
with the mental and spiritual powers of man,
have divided the whole organic world into
three kingdoms, the Human, the Animal, and
the Vegetable, thus giving to man a separate