; all the organs soon get a big dose of the adrenal
secretion, and some of them are strongly affected by it. It hastens
and strengthens the action of the heart, it causes the large veins
inside the trunk to squeeze the blood lagging there back to the heart;
and by these two means greatly quickens the circulation. It also
affects the liver, causing it to discharge large quantities of stored
sugar into the blood. Thus the muscles of the limbs get an unusual
quantity of their favorite fuel supplied them, and also, by the
increased circulation, an unusual quantity of oxygen; and they are
enabled to work with unusual energy. The adrenal secretion also
protects them in some way against fatigue.

While the adrenal secretion is thus exerting a very stimulating
influence on the limb muscles, it is having just the opposite effect
on the digestive organs; in fact it is having the effects described
above as occurring there during anger. These inhibitory effects are
started by the stomach nerves, but are continued by the action of the
adrenal juice {124} on the stomach walls. The rapid secretion of the
adrenal glands during anger is itself aroused by the nerve running to
this gland.

The Nerves Concerned in Internal Emotional Response

There is a part of the nervous system called the "autonomic system",
so called because the organs it supplies--heart, blood vessels,
stomach, intestines and other internal organs, possess a large degree
of "autonomy" or independence. The heart, it will be remembered, beats
of itself, even when cut off altogether from any influence of the
nerve centers; and the same is true in some measure of the other
internal organs. Yet they are subject to the influence of the nerve
centers, which reinforce and inhibit their activity. Each internal
organ has a double supply of nerves, one nerve acting to reinforce the
activity of the organ and the other to inhibit it; and both the
reinforcing and the inhibiting nerves belong to the autonomic system.

The autonomic is not separate from the main nervous system, but
consists of outgoing axons from centers in the cord and "medulla"
(part of the brain stem). It has three divisions, one from the
medulla, one from the middle reach of the cord, and one from the lower
part of the cord; and these three divisions are related to three
different emotional states. The upper division, from the medulla,
favors digestion by promoting the flow of gastric juice and the
churning