the elements in the natural harmony, just as bodily diseases are nothing but abnormal states of wetness or dryness, of heat or cold. For example, what is sharpness of intellect but the fineness and rapid motion of the vital spirit in the brain, which passes through the sensory lobes with very great speed, and rapidly apprehends external objects? But if no obstacle be put in the way of this rapid motion, it dissipates the intellect and leaves the brain either weak or sluggish. Hence it is that so many precocious boys either die young or become stupid.
On the other hand, what is stupidity but a clammy viscosity of the humours of the brain, which can only be set in motion by constant suggestion? What are insolence and intractability but an excess of spirit and stubbornness, which must be tempered by discipline? What is slackness but a great lack of spirit which must be made good? Just as, then, the best remedies for bodily diseases are not those which try to put one extreme to flight by another (for this only makes the struggle greater), but those which seek to moderate all extremes, so that there shall not be too little on one side and too much on the other; so the best remedy against the errors of the human mind is a didactic method of such a kind that by its means excess and defect may be neutralised in the natural disposition, and that all the mental principles may be brought into harmony and into a pleasant agreement. Our method, therefore, is intended for intellects in which no element exists in an extreme form (and indeed these are always the most common), so that neither reins may be wanting to restrain active minds (that they may not wear themselves out before their time) nor spurs and goads to urge on the laggards.
30. Finally: Every excess or defect of disposition can be counteracted as long as it is not of old standing. In warfare, recruits are mixed with old soldiers; the weak and the strong, the sluggish and the active, fight under the same standard and obey the same orders as long as the battle continues. But, when the victory is gained, each pursues
