fer that certain
sensory impulses sent up to the brain attain a strength that finally
forces itself into the conscious field of feeling. The sensation of
hunger varies from individual to individual because of variation in
the reaction throughout the vegetative system. Most often it is a
sense of movement or even an itch in the upper abdomen. Let some cause
produce a weakening or cessation of the movements of the stomach--as
fear and anger--and the sensation of hunger disappears coincidently
with the drop in the pressure within it. As the mathematicians
would say, the wish is a function of the pressure, and so of the
concentration of substance behind the pressure.

We have in hunger the wish reduced to the lowest terms, the most
primitive form of it. Yet we may resolve all wishes, even the most
idealistic, into the same terms. As the vegetative system becomes
habituated by repeated experience to react in the same way to the same
stimulus, permutations and combinations of wishes become possible
until at length the inscrutable complexities of the behaviour of
civilized man are evolved. We have to thank Von Bechterew, the
greatest of Russian physiologists, for these fundamental principles,
so important for the understanding of the control of human life and
conduct.

The associated reflex, aboriginal ancestor of the involved train
of associations that constitute the highest thought, conduct and
character, is the unit of the system. Recall the classic example
cited. If a piece of meat is shown to a dog, his mouth waters. If now
you proceed to ring a bell before offering the meat, his mouth will
water only when he sees or smells the meat. If, however, the ringing
of the bell precedes the meat a sufficient number of reactions, a time
comes when merely the sound of the bell will cause salivation, without
the presence of the meat. So it is with the associated reactions of
the internal secretions. A stimulus originally indifferent to the
endocrines may, by association, the laws of which are many, come to
act like a spark to the endocrine-instinct mechanism. Hence we can
account for the subtle play of instinct throughout all thinking.

Even objects resembling the specific excitant of an instinct only
remotely, or in some one quality, may start its mechanism and a host
of associations bound up with it. Thus the maternal instinct may
be excited by the sight of a baby. But because a baby is small and
delicate, anything small and f