Mental incoherency is the leading trait, and supplies the key for the understanding of the others. Lack of connectedness between ideas is the radical defect. Each idea, as it rises, becomes an impulse, and takes effect to the full limit of its suggestions. A kind thought rises in the mind of such a child, and issues in a demonstrative impulse of affection. Shortly after, a cruel thought may rise in the mind of the same child; and the cruel thought will, in like manner, take effect in a cruel act. Children answering to this type are alternately kind, affectionate, and cruel. The child's indolence is due to the same cause--lack of connectedness between ideas. It is incapable of sustained effort, because every task implies the ability to pass from one idea to related ideas. The child is deficient in shame, because the sense of shame depends on a vivid realization of the idea of self. The idea of self, however, is a complex idea, which is not distinctly and clearly present to such a child. Lastly, the most severe punishments fail to act as deterrents for the same reason. The two impressions left in the mind, "I did a wrong," "I suffered a pain," lie apart. The memory of one does not excite the recollection of the other. The thought of the wrong does not lift permanently into consciousness the thought of the pain which followed. The punishment, as we say, is quickly forgotten. If, therefore, we wish to remedy a deep-seated defect of this kind, if we wish to cure a weak will, in such and all similar cases we must seek to establish a closer connection between the child's ideas. The question may now be asked, Why should we not utilize to this end the ordinary studies of the school curriculum--history, geography, arithmetic, etc.? All of these branches exercise and develop the faculty of serial and complex thinking. Any sum in multiplication gives a training of this kind. Let the task be to multiply a multiplicand of four figures by a multiplier of three. First the child must multiply every figure in the multiplicand by the units of the multiplier and write down the result; then by the tens, and then by the hundreds, and combine these results. Here is a lesson in combination, in serial, and, for a young child, somewhat complex thinking. Let the task be to bound the State of New York. The child must see the mental picture of the State in its relation to other States and parts of States, to lakes and rivers and mountains--a complex group of ideas. Or, let it be required to give a brief account of the American Revolution. Here is a whole series of events, each depending on the preceding ones. Why, then, may we not content ourselves with utilizing the ordinary studies of the school curriculum? There are two reasons.