I. The processes having to do with particular facts are preparation and presentation. The best, indeed the only preparation is arousal to a perception of something that needs explanation, something unexpected, puzzling, peculiar. When the feeling of a genuine perplexity lays hold of any mind (no matter how the feeling arises), that mind is alert and inquiring, because stimulated from within. The shock, the bite, of a question will force the mind to go wherever it is capable of going, better than will the most ingenious pedagogical devices unaccompanied by this mental ardor. It is the sense of a problem that forces the mind to a survey and recall of the past to discover what the question means and how it may be dealt with. [Sidenote: Pitfalls in preparation] The teacher in his more deliberate attempts to call into play the familiar elements in a student's experience, must guard against certain dangers. (_i_) The step of preparation must not be too long continued or too exhaustive, or it defeats its own end. The pupil loses interest and is bored, when a plunge _in medias res_ might have braced him to his work. The preparation part of the recitation period of some conscientious teachers reminds one of the boy who takes so long a run in order to gain headway for a jump that when he reaches the line, he is too tired to jump far. (_ii_) The organs by which we apprehend new material are our habits. To insist too minutely upon turning over habitual dispositions into conscious ideas is to interfere with their best workings. Some factors of familiar experience must indeed be brought to conscious recognition, just as transplanting is necessary for the best growth of some plants. But it is fatal to be forever digging up either experiences or plants to see how they are getting along. Constraint, self-consciousness, embarrassment, are the consequence of too much conscious refurbishing of familiar experiences. [Sidenote: Statement of aim of lesson] Strict Herbartians generally lay it down that statement--by the teacher--of the aim of a lesson is an indispensable part of preparation. This preliminary statement of the aim of the lesson hardly seems more intellectual in character, however, than tapping a bell or giving any other signal for attention and transfer of thoughts from diverting subjects. To the teacher the statement of an end is significant, because he has already been at the end; from a pupil's standpoint the statement of what he is _going_ to learn is something of an Irish bull. If the statement of the aim is taken too seriously by the instructor, as meaning more than a signal to attention, its probable result is forestalling the pupil's own reaction, relieving him of the responsibility of developing a problem and thus arresting his mental initiative. [Sidenote: How much the teacher should tell or show]