sential to understand thoroughly the
organs of sense and their special functions.

It is further necessary to study the co-ordination which exists between
the action of the different senses, and leads to their intimate
connection with the functions of the nerve-centres, that is to say, with
the specially instinctive intelligence of insects. The whole question
is, therefore, a chapter of comparative psychology, a chapter in which
it is necessary to take careful note of every factor, to place oneself,
so to speak, on a level with the mind of an insect, and, above all, to
avoid the anthropomorphic errors with which works upon the subject are
filled.

At the same time the other extreme must equally be
avoided--"anthropophobia," which at all costs desires to see in every
living organism a "machine," forgetting that a "machine" which lives,
that is to say, which grows, takes in nutriment, and strikes a balance
between income and expenditure, which, in a word, continually
reconstructs itself, is not a "machine," but something entirely
different. In other words, it is necessary to steer clear of two
dangers. We must avoid (1) identifying the mind of an insect with our
own, but, above all, (2) imagining that we, with what knowledge we
possess, can reconstruct the mind by our chemical and physical laws.

On the other hand, we have to recognise the fact that this mind, and the
sensory functions which put it on its guard, are derived, just as with
our human selves, from the primitive protoplasmic life. This life, so
far as it is specialised in the nervous system by nerve irritability and
its connections with the muscular system, is manifested under two
aspects. These may be likened to two branches of one trunk.

(_a_) _Automatic_ or _instinctive_ activity. This, though perfected by
repetition, is definitely inherited. It is uncontrollable and constant
in effect, adapted to the circumstances of the special life of the race
in question. It is this curious instinctive adaptation--which is so
intelligent when it carries out its proper task, so stupid and incapable
when diverted to some other purpose--that has deceived so many
scientists and philosophers by its insidious analogy with humanly
constructed machines.

But, automatic as it may appear, instinct is not invariable. In the
first place, it presents a racial evolution which of itself alone
already demonstrates a certain degree of plasticity from generation to
generation. It