en gives way to rest. Introspectively, what we
feel (apart from any clear mental picture of the goal) is a
restlessness and tenseness during a series of acts, giving way to
relief and satisfaction when a certain result has been reached.

A hungry or thirsty animal is restless; he _seeks_ food or drink,
which means that he is making a series of preparatory reactions, which
continues till food or drink has been found, and terminates in the
end-reaction of eating or drinking.

What the Preparatory Reactions Accomplish

The behavior of a hungry or thirsty individual is worth some further
attention--for it is the business of psychology to interest itself in
the most commonplace happenings, to wonder about things that usually
pass for matters of course, and, if not to find "sermons in stones",
to derive high instruction from very lowly forms of animal behavior.
Now, what is hunger? Fundamentally an organic state; next, a sensation
produced by this organic state acting on the internal sensory nerves,
and through them arousing in the nerve centers an adjustment or
tendency towards a certain end-reaction, namely, eating. Now, I ask
you, if hunger is a stimulus to the eating movements, why does not the
hungry individual eat at once? Why, at least, does he not go through
the motions of eating? You say, because he has nothing to eat. But he
could still make the movements; there is no physical impossibility in
his making chewing and swallowing movements without the presence of
food. {80} Speaking rationally, you perhaps say that he does not make
these movements because he sees they would be of no use without food
to chew; but this explanation would scarcely apply to the lower sorts
of animal, and besides, you do not have to check your jaws by any such
rational considerations. They simply do not start to chew except when
food is in the mouth. Well, then, you say, chewing is a response to
the presence of food in the mouth; and taking food into the mouth is a
response to the stimulus of actually present food. The response does
not occur unless the stimulus is present; that is simple.

Not quite so simple, either. Unless one is hungry, the presence of
food does not arouse the feeding reaction; and even food actually
present in the mouth will be spewed out instead of chewed and
swallowed, if one is already satiated. Try to get a baby to take more
from his bottle than he wants! Eating only occurs when one is _both_
hungry and in the