every child inherits the ability to do one thing only, and will waste his life if he does not happen to get a chance to do that thing. It is easy to suppose that the man who makes a failure as a paperhanger might, if he had had the opportunity, have been a great electrical engineer; it is easy to cite a few cases, such as that of General U. S. Grant, which seem to lend some color to the theory, but statistical evidence would indicate it is not the rule. If a man makes a failure as a paperhanger, it is at least possible that he would have made a failure of very many things that he might try; and if a man makes a brilliant success as a paperhanger, or railway engineer, or school teacher, or chemist, he is a useful citizen who would probably have gained a fair measure of success in any one of several occupations that he might have taken up but not in all.
To sum up: vocational guidance and training are likely to be of much service to eugenics. They may derive direct help from heredity; and their exponents may also learn that a man who is really good in one thing is likely to be good in many things, and that a man who fails in one thing would not necessarily achieve success if he were put in some other career. One of their greatest services will probably be to put a lot of boys into skilled trades, for which they are adapted and where they will succeed, and thus prevent them from yielding to the desire for a more genteel clerical occupation, in which they will not do more than earn a bare living. This will assist in bringing about the high correlation