begins in utero (there is no reason to suppose that conditioned
reflexes do not begin there), and probably several hereditary
modes of action (particular types of reflexes) run their entire
course in utero. But we are entering here upon a field which
just at present is purely speculative.

What Is an Emotion? --Hard and fast definitions are not
possible in the psychology of emotion, but formulations are pos-
sible and sometimes help us to group our facts. A formulation
which will fit a part of the emotional group of reactions may be
stated as follows: An emotion is an hereditary "pattern-reac-
tion," involving profound changes of the bodily mechanism as
a whole, but particularly of the visceral and glandular systems.¹
By pattern-reaction we mean that the separate details of response
appear with some constancy, with some regularity and in approx-
imately the same sequential order each time the exciting stimulus
is presented. It is obvious that if this formulation is to fit the
facts, the general condition of the organism must be such that
the stimulus can produce its effect. A child alone in a house on
a stormy night with only a dim candle burning may display the
reaction of fear at the mournful hoot of an owl. If the parents
are at hand and the room is well lighted, the stimulus may pass
unreacted to. Stimulus then in this sense is used in a broad
way to refer not only to the exciting object but also to the gen-
eral setting (page 10 ). There is implied also the fact that the
general state of the organism must be sensitive (capable of being
stimulated) to this form of stimulus at the moment. This con-
dition is very important. A young man may be extremely sen-
sitive to the blandishments of every female he meets while in
the unmarried state and may show considerable excitement and

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