slightly
in a state
of nature.
No one
will
dispute
that
instincts
are of the
highest
importance
to each
animal.
Therefore
I can see
no
difficulty,
under
changing
conditions
of life,
in natural
selection
accumulating
slight
modifications
of
instinct
to any
extent, in
any useful
direction.
In some
cases
habit or
use and
disuse
have
probably
come into
play. I do
not
pretend
that the
facts
given in
this
chapter
strengthen
in any
