ine, a tiny book, a toy, a miniature,
may arouse it. The object is then said to be appealing. The doctrine
of association of instinctive and so of endocrine reactions enables
us to understand the feeling--tone that at any moment pervades
consciousness as well as its content.

Choices, the psychology of selection of food, color, friends, mates,
amusements also become explicable rationally. For conflicts among
the different components of the vegetative system are continuous and
inevitable. If the pressure within a viscus has been heightened, and
persists, that is, is not disturbed by some other associated factor or
instinct, conduct results to lower the pressure to what it was before
the instigator of the tension appeared. But if another instinct is
sparked, or another associated factor comes into play, another focus
of increased pressure within the vegetative system is created, with
another stream of energy flowing to the brain and demanding an outlet.
This clash of instincts, the struggle between different foci of the
vegetative system competing for the possession of the brain, is a
common everyday process in conduct. Which will win means which will
will. And so we have an energetic basis for volition.

Which will win appears to depend primarily upon the kind of endocrines
that predominate in the make-up of the individual, secondarily with
his education. For it is the endocrines that are really in conflict
when there is a struggle between two instincts. And if one endocrine
system conquers, it must be either because it is inherently stronger,
its secretion potential, that is, the amount of secretion it can put
forth as a maximum, is greater (so explaining the term dominant)--or
because a past experience has conditioned it to respond, although the
opposing endocrine system does not. Fear and anger, respectively bound
up with the activities of the adrenal medulla and cortex, we shall
see, provide as good exemplars as any of this process.

The response of the ductless glands to situations varies with their
congenital _capacity_, and acquired _susceptibility_. Capacity is
a question of internal chemistry, modifiable by injury, disease,
accident, shock, exhaustion. Susceptibility depends upon the play of
the forces focusing upon them that may be summed up as associations.
In the ability of one endocrine system to inhibit another we have the
germ of the unconscious. Hence the modus operandi of the repressions
and suppressi