=B. Saves Time.=--There is the further advantage of economy of time, when an adequate preparation of the mind has been made. When the appropriate ideas are definitely in the forefront of consciousness, they seize upon kindred impressions as soon as these are presented and give them meaning. On the other hand, when sufficient preparation has not been made, time must be taken during the presentation of the new problem to go back in search of those experiences necessary to make it meaningful. Frequent interruptions and consequent waste of time will be inevitable. Time will be saved by having the apperceiving ideas ready and active.
=C. Provides for Review.=--One of the most important values of the preparatory step is the opportunity given for the review of old ideas. These have to be revived, worked over, and reconstructed, and in consequence they become the permanent possessions of the mind. The pupil's knowledge of the functions of the adverb is reviewed when he learns the adverb phrase and adverb clause, and is still further illuminated when he comes to study the adverbial objective. Further, the apperceiving ideas become more interesting to the pupil, when he finds that he can use them in the conquest of new fields. He has a consciousness of power, which in itself is a source of satisfaction and pleasure.
=Must not be too Long.=--Two precautions seem advisable in the preparatory step. The first is that too long a time should not be spent over it. There is sometimes a tendency to go back too far and drag forward ideas that are only remotely connected with the new ideas to be presented. Under such conditions much irrelevant material is likely to be introduced, and often a train of associations out of harmony with the meaning and spirit of the lesson is started. This is especially dangerous in lessons in literature and history. Only those experiences should be revived which are necessary to a clear apprehension of the ideas or a full appreciation of the emotions to be presented in the new lesson.
=Must Recall Vital Ideas.=--The most active, vivid, and powerful ideas in the pupil's mind are those which are closely connected with his life. This suggests the second precaution, namely, the use wherever possible of the ideas associated with his surroundings, his games, his occupations. When this is done, not only will the new knowledge have a much greater interest attached to it but it will also be much more vividly apprehended. This will be referred to further in connection with the use of illustrations in teaching.