There are other impulses, such as love of approbation or vanity, shyness and secretiveness, of which a word might be said; but they are too familiar to need it.  You can easily pursue the subject by your own reflection.  There is one general law, however, that relates to many of our instinctive tendencies, and that has no little importance in education; and I must refer to it briefly before I leave the subject.  It has been called the law of transitoriness in instincts.  Many of our impulsive tendencies ripen at a certain period; and, if the appropriate objects be then and there provided, habits of conduct toward them are acquired which last.  But, if the objects be not forthcoming then, the impulse may die out before a habit is formed; and later it may be hard to teach the creature to react appropriately in those directions.  The sucking instincts in mammals, the following instinct in certain birds and quadrupeds, are examples of this:  they fade away shortly after birth.

In children we observe a ripening of impulses and interests in a certain determinate order.  Creeping, walking, climbing, imitating vocal sounds, constructing, drawing, calculating, possess the child in succession; and in some children the possession, while it lasts, may be of a semi-frantic and exclusive sort.  Later, the interest in any one of these things may wholly fade away.  Of course, the proper pedagogic moment to work skill in, and to clench the useful habit, is when the native impulse is most acutely present.  Crowd on the athletic opportunities, the mental arithmetic, the verse-learning, the drawing, the botany, or what not, the moment you have reason to think the hour is ripe.  The hour may not last long, and while it continues you may safely let all the child’s other occupations take a second place.  In this way you economize time and deepen skill; for many an infant prodigy, artistic or mathematical, has a flowering epoch of but a few months.

One can draw no specific rules for all this.  It depends on close observation in the particular case, and parents here have a great advantage over teachers.  In fact, the law of transitoriness has little chance of individualized application in the schools.

Such is the little interested and impulsive psychophysical organism whose springs of action the teacher must divine, and to whose ways he must become accustomed.  He must start with the native tendencies, and enlarge the pupil’s entire passive and active experience.  He must ply him with new objects and stimuli, and make him taste the fruits of his behavior, so that now that whole context of remembered experience is what shall determine his conduct when he gets the stimulus, and not the bare immediate impression.  As the pupil’s life thus enlarges, it gets fuller and fuller of all sorts of memories and associations and substitutions; but the eye accustomed to psychological analysis will discern, underneath it all, the outlines of our simple psychophysical scheme.