We need to distinguish between insertion and continuation, and to connect this distinction with the division of ideas into spontaneous and induced (71). It is easier to fill in between familiar points than it is to continue, because the continued series is in close contact with the well known only at the starting-point. Easiest of all is insertion between free-rising ideas, between those ideas that occur to the pupil spontaneously, when he has been led into a certain field of consciousness. Hardest of all, and least certain of success, is the continuation of lessons that can be revived in consciousness only by a laborious effort of memory. Intermediate in difficulty are the insertion of new elements between induced or reproduced ideas, and continuation on the basis of free-rising, or spontaneous, ideas. That there may be many gradations besides is of course self-evident. The teacher who knows his pupils well will be able to make frequent use of these distinctions. Only a very general outline of their application can be given here. The realia and mathematics can be connected more easily than other studies with the pupil’s experience (101, 102). If the teacher has properly availed himself of this advantage, he may count on ideas that rise spontaneously, and his task will then consist in first establishing a few suitable cardinal points so that insertions may be made farther on. Languages present more serious difficulties. It is true that progress in the vernacular is made through apperception by the pupil’s earlier attainments in his mother-tongue, and through the insertion of the new into the old. But in foreign languages, which associate themselves with the mother-tongue only gradually, apperception and insertion cannot take place until after some knowledge of the language has been acquired. And this knowledge must grow considerably before we can reasonably look for spontaneous ideas. If now the reproduced ideas become encumbered with additional new ones, worst of all through mere continuation, we need not wonder if the result is useless chaos.