Interest depends partly, it is true, on native capacity, which the school cannot create; but it depends also on the subject-matter of instruction. 126. Synthetic instruction must offer subjects capable of arousing lasting and spontaneously radiating interest. That which affords only temporary pleasure or light entertainment is of too little consequence to determine the plan of operation. Nor can the choice of such studies be recommended as stand isolated, as do not lead to continued effort; for, other reasons aside, we are unable to decide beforehand to which of the main classes of interest (83–94) the individual pupil will especially incline. The first place belongs rather to those studies which appeal to the mind in a variety of ways and are capable of stimulating each pupil according to his individuality. For such subjects ample time must be allowed; they must be made the object of prolonged, diligent effort. We may then hope that they will take hold in some way, and we shall be in a position to know what kind of interest they have inspired in one pupil or another. Where, on the contrary, the end of the thread of work is soon reached, it remains questionable whether any effort at all will be produced, let alone a lasting impression. 127. The subject-matter having been chosen, the treatment must be adjusted to it in such a way as to bring it within reach of the pupils. For the exercises growing out of such treatment, the well-known rule holds in general: the easy before the difficult, or, more specifically, that which prepares the way before that which cannot be firmly grasped without preliminary knowledge. To insist, however, on perfect mastery in this respect, is often equivalent to scaring away interest. Absolute proficiency in preliminary knowledge is a late achievement, nor is it attained without fatigue. The teacher has to be satisfied if the mastery acquired is such that what is lacking can, without serious delay, be added by him in practice. To make the road so level as to do away entirely with the necessity for occasional leaps (96), means to provide for the convenience of the teacher rather than for that of the pupils. The young love to climb and jump; they do not take kindly to an absolutely level path. But they are afraid in the dark. There must be light enough for them to see by; in other words, the subject must lie spread out before their eyes with such distinctness that each step is seen to be a step forward, which brings them perceptibly nearer to a distant goal.