Even children who pass as "average" children, however, may be divided into classes according to the variations in their native capacities. That is to say, some children, although not exhibiting any special talents or special deficiencies, are nevertheless more easily adjusted to doing muscular work than others; some are more happy in the manipulation of numbers; some show greater patience; some are more easily fatigued by the repetition of a process; some cannot stand on their feet for long periods without suffering, and so on. These differences should certainly be taken into consideration, first of all, in the treatment accorded them in the school and at home, in what is required of them, in the selection of studies, etc. And, in the second place, these facts should be considered in the choice of general fields of occupation. It would be the height of cruelty and of injustice to insist upon Walter's preparing for and entering his father's business--just to keep up the family tradition--when a little attention to the boy's work in school and to his play and to his personal preferences and tastes would show that he was eminently unsuited for the business, and at the same time well suited for some technical pursuit such as engineering. Untold misery and failure spring from our negligence in these matters, no less than from our direction of the child's development in accordance with the parents' ambitions rather than in accordance with the child's discoverable abilities and disabilities. How far short our ordinary training falls of giving our various capacities their full development is shown by the exquisite acuteness of touch and of hearing acquired by children who become blind in infancy. The senses of touch and hearing are here developed so far beyond what ordinary persons ever attain that the belief is quite common that one who is defective in one sense has been compensated by "nature" with special capacity in the other senses. As a matter of fact, however, the extreme development is not the result of special endowment or "heredity," but altogether the result of special training or "environment."