As I have repeatedly remarked, psychology must strictly individualize; and I can imagine nothing more preposterous or unscientific than to assume a so-called normal man, and to conclude that anything which widely departs from that norm is diseased. We have seen that all phenomena of pronounced mental disease arise from the same psychical elements as the healthy action of the mind. We have further seen that the mental life of those great men whom we call geniuses presents no other psychical conditions than those of ordinary men, except for differences of quantity. “Health and disease,” says Claude Bernard, “are not two essentially different forms, as the old physicians could believe, and as many practitioners still believe. They are not to be regarded as distinct principles, as entities disputing for the living organism, and making it the theatre of their war. Those sorts of ideas belong in the medical lumber-room. But, in fact, between any form of disease and health there are only differences of degree. No disease is anything more than an exaggeration, or disproportion, or an harmony of normal phenomena.”

This is true of all diseases whatsoever, whether they be of corporeal or of mental origin. Hence the decision whether anything is to be considered as a disease or not cannot be made to depend upon how far the phenomena depart from a norm. The only question is, whether the vital action of the organism is prejudiced or the performance of the individual deranged. Take, for example, bodily deformities or other perturbations of development. The only question is whether the individual concerned is disabled or not. A woman with a contracted pelvis, if she be otherwise normal and her organs act normally, will not be called diseased; but as soon as she becomes pregnant she becomes a pathological subject, because parturition cannot take place in the normal way. A man whose lungs are ill developed, so that the slightest exertion produces dyspnoea, must be considered as ill, while another man with uncommonly large lungs, such as fast runners generally have, is certainly not to be called diseased on account of this abnormality.

People with bodily deformities, or anomalies of development, frequently find themselves in situations in which they cannot fulfill some requirements of business; and it depends upon the degree of their incapacity how far their anomalies are to be reckoned as pathological. The laity are frequently able to decide what can be expected of such people, and what not. The subjects can often estimate for themselves what they can undertake. Nobody would accept a dwarf for military service, and a weak man will be conscious that he is not fit to be a drawer of stones.