tions of the body will go on
better without its interference. It is not yet sufficiently
developed, or, so to speak, wise enough to be intrusted with much
control of the animal.

Among higher worms cases of instinct seem proven. Traces of it will
almost certainly be yet found much lower down. Fresh-water mussels
migrate into deeper water at the approach of cold weather. And if
the clam has instincts, there is no reason why the turbellaria
should not also possess them. But all higher powers develop
gradually, and their beginnings usually elude our search. Along the
line leading from annelids to insects instinct is becoming dominant.
A supraoesophageal ganglion has developed, and has been relieved
of most of the direct control of the muscles. Very good sense-organs
are also present. From this time on consciousness becomes clearer,
and the brain is beginning to assert its right to at least know what
is going on in the body, and to have something to say about it.
Still, as long as the actions remain purely instinctive the brain,
while conscious, is governed by heredity. The animal does as its
ancestors always have. It does not occur to it to ask why it should
do thus or otherwise, or whether other means would be better fitted
to the end in view. It acts exactly like most of the members of our
great political and theological parties. And until the animal has a
better brain this is its best course and is favored by natural
selection.

But the hand of even the best dead ancestors cannot always be
allowed to hold the helm. The brain is still enlarging, the
sense-organs bring in fuller and more definite reports of a wider
environment. Greater freedom of action by means of a stronger
locomotive system is bringing continually new and varied
experiences. And if, as in vertebrates, longer life be added,
frequent repetition of the experience deepens the impression.
Slowly, as if tentatively, the animal begins to modify some of its
instincts, at first only in slight details, or to adopt new lines of
action not included in its old instincts, but suited to the new
emergencies. This is the dawn of intelligence. Its beginnings still
remain undiscovered. Mr. Darwin believes that traces of it can be
found in earthworms and other annelids. He also tells us that
oysters taken from a depth never uncovered by the sea, and
transported inland, open their shells, lose the contained water, and
die; but that left in reservoirs, where they are oc