Thus in education, a fact to be learned, or a subject to be studied, should be first sketched or placed in some use value to the student. Knowledge for knowledge's sake is appealing only to the rare scholar, he who palpitates with interest over the relationship of things to one another, he who seeks to discover values. Now and then one finds such a person, one thrown into sustained excitement by learning, but the great majority of students, whether in medicine, law or mathematics, are "practical," meaning that their interests are relatively narrow and the good they seek an immediate one to be reaped by themselves. Recognizing this fact in the abstract, the most of teaching is conducted on the plane of the real scholar, and the average student is left to find values for himself. From first to last in teaching I would emphasize usevalue; true, I would seek to broaden the conception of usevalue, so that a student would see that usefulness is a social value, but no matter how abstract and remote the subject, its relationship to usefulness would be preliminary and continuously emphasized in order to sustain interest. Interest, like any other form of excitement, needs new stimuli and periods of relaxation. People under the driving force of necessity continue at their work for longer periods of time and more constantly than is psychologically possible for the maintaining of interest. So it disappears, and then fatigue sets in at once,--a fatigue that is increased by the effort to work and the regret and rebellion at the change. The memory seems to suffer and a fear is aroused that "I am losing my memory"; the threat to success brings anguish and often the health becomes definitely impaired. Overconcentrated, too long maintenance of interest brings apathy,--an apathy that cannot be dispelled except by change and rest. Here there is wide individual variation from those who need frequent change and relaxation periods to those who can maintain interest in a task almost indefinitely. A hobby, or a secondary object of interest, is therefore a real necessity to the man or woman battling for a purpose, whose interest must be sustained. It acts to relax, to shift the excitement and to allow something of the feeling of novelty as one reapproaches the task. As a matter of fact, excitement and interest are not easily separated from their derivatives and elaborations. Desire, purpose, ambition, imply a force; interest implies a direction for that force. Interest may be as casual as curiosity aroused by the novel and strange, or as deep-seated and specialized as a talent. The born teacher is he who knows how to arouse and maintain and direct interest; the born achiever is the man whose interest, quickly aroused, is easily maintained and directs effort. To find the activity that is natively interesting and yet suited to one's ability is the aim in vocational guidance.