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Quick march! it may be questioned whether the old habit
of obedience would have prevailed. The loss of the
pie would have broken the charm. In the same way,
every instinct which was once an intelligent action may be
accompanied by a sub-consciousness which could not
be altogether unobservant of advantage or disadvantage in
connection with some useful modification or with some
change of the external conditions.
Mr. Romanes adduces the following illustration of the
fact that intelligence acts up to a certain point; and that
Natural Selection then comes in to perfect the instinctive
action.
“The grouse of North America display the curious instinct of
burrowing a tunnel just below the surface of the snow. In the end
of this tunnel they sleep securely ; for when any four-footed enemy
approaches the mouth of the tunnel, the bird, in order to escape, has
only to fly up through the thin covering of snow. Now in this case
the grouse probably began to burrow for the sake of protection or
concealment, or both; and, if so, thus far the burrowing was probably
an act of intelligence. But the longer the tunnel, the better would it
have served the purposes of escape, and therefore Natural Selection
would almost certainly have tended to preserve the birds which made
the longest tunnels, until the utmost benefit that length of tunnel
could give had been attained.”—(.Mental Evolution in Animals,
p. 202.)
The theoretical explanation given in the above passage
implies—first, that safety was due to the length of the
“ burrow,” and, secondly, that the precise length of it
was determined not by the continued action of the intel
ligence of the bird, but by the survival of those individuals
which, by a happy accident, chanced to make a “ burrow ”
of the right length. Now, let us consider the circum
stances under which the length of the tunnel would prove
a source of safety. In order that the grouse should escape
it must be able to fly up easily from under the superin
cumbent snow. It would be fatal for it to be buried in
