There is yet one other point of analogy between the supply of food for the body and the mind, to which we must also allude. It is to be found in the baneful, and often destructive, effects of unnatural stimulants applied to the mental appetite, which strikingly correspond in their effects to the pernicious habit of supplying stimulants to the young in their ordinary food.--Stimulants will no doubt, in both cases, produce for the time additional excitement;--but they are neither natural nor necessary. In all ordinary cases, Nature has made ample provision for the supposed want, of which the craving--the natural and healthy craving--of children for knowledge and for food, gives ample testimony. To counteract or to weaken this natural desire would be improper;--but artificially to _increase_ it is always dangerous. The reason is obvious; for the excitement thus caused being unnatural, it is always temporary; but its pernicious effects very soon become extensive and permanent. Every physician knows, that the habitual use of stimulants in the food of the young, weakens the tone of the stomach, palls the appetite, creates a disrelish for plain and wholesome food, and frequently destroys the powers of digestion for ever after. Very similar are the effects of unnatural stimulants to the mental appetite in training and teaching the young, when these stimulants are habitually, or even frequently administered. Their curiosity,--their appetite for knowledge,--is naturally so vigorous, that the repetition, or the reading of any story, however commonplace or uninteresting to us, gives them the sincerest pleasure, provided only that they understand and can follow it. This is a most wise and beneficent provision of Nature, of which parents and teachers should be careful to take advantage. It is because of this disposition in children, that in all ordinary cases, the simplest narrative or anecdote in ordinary life, may be successfully employed in giving them mental strength, and in communicating permanent moral instruction. But whenever unnatural and injudicious excitements are used in their instruction, and the child's imagination has been stimulated and defiled by the ideas of giants and ogres, fairies and ghosts, the whole natural tone of the mind is destroyed, plain and even interesting stories and narratives lose their proper attraction, and a diseased and insatiable appetite for the marvellous and the horrible is generally created. Even to adults, and much more to children, whose minds have been thus abused, the plain paths of probability and truth have lost every charm; and the study of abstract but useful subjects becomes to them a nauseous task--an intolerable burden.