starter of the whole process, and since McDougal has defined emotion
as the feeling aspect of an instinct, just as an instinct may
be defined as the motor aspect of an emotion, the adrenals as
emotion-genetic, and instinct-genetic, play a part in the most
profound processes of the subconscious and unconscious.

THE MECHANISM OF FEAR

We may therefore visualize a mechanism of fear. An instant excess of
adrenalin occurs in the blood of, say, a cat when it is alarmed by the
sight of a dog. In that cat, at the image of its hereditary enemy,
certain brain cells vibrate. A nerve tract, in use as the line for
that particular message in a hundred thousand generations of cats,
whirrs its yell to the medulla of the adrenal gland. Through the tiny,
solitary veins of the glands, an infinitesimal quantity of the reserve
adrenalin responds. And with what an effect! The blood, that primary
medium of life, the precious fluid that is everything, must all, or
nearly all, be sent to the firing line, the battle trenches, the
brain and muscles, now or never. So the blood is drafted from the
non-essential industries--from the skin where it serves normally to
regulate the heat of the body--from the digestive organs, the stomach
and intestine, which must forsooth stop now, since if the organism
will die, their last effort of digestion has been done--from the liver
and spleen, great chemical factories in normal times, but now of no
moment. Besides, should they be wounded, it is better they should
be bloodless, and so run the least chance of bleeding to death, or
getting infected, for the more tissue there is around, the greater the
danger of infection. So, like the skin, the liver which usually holds
in its great lakes and vessels about a quarter of all the blood in
the body, is almost drained and blanched. At the same time, its great
storehouses of sugar open their sluices and pour into the blood,
increasing its sugar content by about a third because the combustion
of sugar is the easiest way of getting energy free in the cells, sugar
being the most quickly burned up of all the foods, and so the great
food of the muscles and the heart. The poisons of fatigue, acid
products of the contraction of muscles, are antagonized and
neutralized by substances formed in the course of the oxidation of the
sugar. Adrenalin, too, is directly fatigue antagonist. It causes the
blood to clot faster than under ordinary circumstances. It erects the
hair of the