nervous current back to the visual area of the brain, the transmission
of the current over association neurones to the motor area, then its
transmission over the motor neurones, down the spinal cord, to the
muscles that enable you to dodge the missile. The association neurones
have the further function of connecting one sensory area in the brain
with another. For example, when you see, smell, taste and touch an
orange, the corresponding areas in the brain act in conjunction and are
associated by means of the association neurones connecting them. The
association neurones play a large part in the securing and organizing
of knowledge. They are very important in study, for all learning
consists in building up associations.

From the foregoing description we see that the nervous system consists
merely of a mechanism for the reception and transmission of incoming
messages and their transformation into outgoing messages which produce
movement. The brain is the center where such transformations are made,
being a sort of central switchboard which permits the sense-organs to
come into communication with muscles. It is also the instrument by
means of which the impressions from the various senses can be united
and experience can be unified. The brain serves further as the medium
whereby impressions once made can be retained. That is, it is the great
organ of memory. Hence we see that it is to this organ we must look for
the performance of the activities necessary to study. Everything that
enters it produces some modification within it. Education consists in a
process of undergoing a selected group of experiences of such a nature
as to leave beneficial results in the brain. By means of the changes
made there, the individual is able better to adjust himself to new
situations. For when the individual enters the world, he is not
prepared to meet many situations; only a few of the neural connections
are made and he is able to perform only a meagre number of simple acts,