's whole soul does one contemplate
the object of attention. If we regard the acquired knowledge as the
objective result of apperception, interest must be regarded as the
subjective side." (Lange, Apperception, page 19.)

Finally, the _will_ has much to do with conscious efforts at
apperception. It holds the thought to certain groups; it excludes or
pushes back irrelevant ideas that crowd in; it holds to a steady
comparison of ideas, even where perplexity and obscurity trouble the
thinker. When the process of reaching a conclusion takes much time,
when conflict or contradiction have to be removed or adjusted, when
reflection and reasoning are necessary, the will is of great importance
in giving coherency and steadiness to the apperceptive effort. A
conscious effort at apperception, therefore, may include many elements,
sense perceptions, ideas recalled, feeling, _will_.

"Let us now sum up the essentials in the process of apperception.
First of all, an external or internal perception, an idea, or
idea-complex appears in consciousness, finding more or less response in
the mind; that is, giving rise to greater or less stimulation to
thought and feeling.

"In consequence of this, and in accordance with the psychical mechanism
or an impulse of the will, one or more groups of thoughts arise, which
enter into relation to the perception. While the two masses are
compared with one another, they work upon one another with more or less
of a transforming power. New thought-combinations are formed, until,
finally, the perception is adjusted to the stronger and older thought
combination. In this way all the factors concerned gain in value as to
knowledge and feeling; especially, however, does the new idea gain a
clearness and activity that it never would have gained for itself.
_Apperception is, therefore, that psychical activity by which
individual perceptions, ideas, or idea-complexes are brought into
relation to our previous intellectual and emotional life, assimilated
with it, and thus raised to greater clearness, activity, and
significance._" (Lange, Apperception, page 41.)

Important _conclusions_ drawn from a study of apperception:

1. _Value of previous knowledge_. If knowledge once acquired is so
_valuable_ we are first of all urged to make the acquisition permanent.
Thorough mastery and frequent reviews are necessary to make knowledge
stick. Careless and superficial study is injurious. It is sometimes
care