Many individuals behave badly because of defects which they bring into the world with them. Hereditary taints are often difficult to distinguish from acquired ones. The influence of the environment very often accentuates hereditary defects. In the children of alcoholics, for example, the congenital inferiority of the tissues and the mind is aggravated by the disorder, dirt, ignorance and misery of the home background. Nearly always, innate vices develop rather than diminish in the course of a lifetime. Certain features of the face and, as Galton has shown, certain qualities of mind frequently characterize a family for several generations. The same applies to feeble-mindedness and madness. Criminality, however, is only transmitted hereditarily insofar as it is linked with mental disease.

The son of a thief or a murderer is more likely to behave rationally than the son of a madman. Individuals whose behavior is congenitally vitiated are found in all classes of society. Eugenism is the most neglected of all disciplines. Submen are frequently found among the descendants of alcoholics, drug-fiends and syphilitics. They also come from stock which has produced moral idiots, imbeciles and perverts. But they still occur in highly moral families, for the nervous or mental defect of an ancestor can reappear suddenly among his descendants. Before they are born, such individuals are destined to be more or less completely incapable of directing their own lives.

They belong to very different types. There are the hypersensitive who turn in on themselves before the difficulties of life, who are hurt by every obstacle or who rush into action without sufficient thought. There are the unstable whose existence is passed in starting enterprises and never finishing them; there are the dreamers, the erratic and the aboulic with their plans that never materialize; there are those whose judgment is chronically false and who are invariably wrong in their estimates of men and events. There are the lazy, immobilized in pathological inertia; the envious who, incapable of acting themselves, are content to criticize others; the moral idiots, characterized by emotional deficiencies ranging from mere clouding of the moral sense to definite perversion. There are also the host of the small-minded, the weak and the semi-invalid whom fear makes malicious. Perhaps the strange perfidy and hatred which characterize certain nations have weakness, stupidity and cowardice as their principal cause.

Many of these defects are only partially hereditary in origin. It is impossible to determine in which measure they are attributable to the structure of the tissues and the consciousness or to bad habits acquired during development. Nevertheless, we can be sure that extreme types of feeblemindedness, mental unbalance, impulsiveness, apathy and malice are the expression of the original poor quality of soul and body.

There are many degrees in this inaptitude for rational conduct. A small part of the population can act in such a way as to be dangerous to the majority. Madmen, idiots and criminals are quite unfit to be allowed to conduct their lives freely and it is necessary to segregate them. A second category consists of those who are physically and mentally stunted: these, without being dangerous to the community, axe nevertheless a burden on it. Such are the weak, the tuberculous, the unadaptable and the chronically idle.

A third category contains those who are fit to conduct their own material existence but who cause division and disorder in the community by their absence of moral sense and in particular by their habit of backbiting and scandal-mongering.

It is impossible to distinguish, among these people who are only partially incapable of behaving reasonably, those who are obeying hereditary inclinations from those who are the victims of education and environment. But both alike are more harmful to society than those whose total unfitness to conduct their own lives has caused them to be shut away.

What is the proportion of those whose ancestral defects prevent them from conforming to the rules of life? No inventory has been made of hereditary syphilitics; of the children of alcoholics; of the descendants of the feeble-minded, moral idiots or the insane.

American statistics have shown that the population contains 4 to 5 per cent of individuals susceptible to mental disturbances and 3 per cent of criminals, not counting mental defectives. This means that in every thousand persons in the United States there are at least a hundred incapable of conforming to the moral disciplines of existence. In France we have not even such very approximate statistics but we know that there are probably as many insane people as in the United States.

The majority of taints in the French people are not of ancestral origin. Probably more than half the population has an inherited patrimony good enough to permit it to behave reasonably well.