Page:Popular Science Monthly Volume 33.djvu/351

Rh was considered as an absolute whole, sufficient in himself, and having no roots in the past. But the theory might almost be established a priori, for it is certain that heredity plays a part in the physical man. Every one recognizes the existence of hereditary diseases and the resemblance of children to parents. It is also generally acknowledged that the physical exercises a certain influence over the moral; it follows, therefore, that what is transmitted by the physical may be communicated, in a certain measure, to the moral. Yet much precaution is needed in the interpretation of these facts, for the law of heredity has to compete with another psychological law, that of imitation or of contagion by madness, the delusion, and the same delusion, is communicated to another by contagion and not by heredity. Undoubtedly, if the case is one of mother and daughter, it might be maintained that heredity plays a part; but, in the case of two sisters, there example. It is necessary, therefore, in discussing the facts on which the thesis of psychological heredity is supported, to select those with which it is possible to disengage these two elements from one another.

The fact of hypnotic suggestion, which has been so much talked of recently that it has nearly become wearisome, is nevertheless one of the most certain and best established facts. It causes astonishment solely by the extraordinary consequences which have been seen to be produced by it; for, at bottom, it was not unknown. It is a familiar fact that there can always be more or less of communication, in normal sleep, between the sleeper and the persons around him. No one is surprised, for example, that when music is performed in the presence of a person who sleeps through it without waking, he will say on waking that during his sleep he attended a concert of angels. The sensation has been entangled with the sleep, and has suggested by association a series of images which have a relation to it. It is known, also, that we can, in some cases, act upon the sleeping man, and obtain responses by speaking, or excite and direct his dreams by some other mark. This elementary fact, exaggerated and developed in certain organizations, and in particular diseases, especially in hysteria, has become the extraordinary fact of suggestion with all its consequences. It is not impossible to find its origin in the normal state. If we tell an infant that the murmuring wind is the voice of a weeper, or that a pale reflection of moonlight is a ghost, it will hear voices and see ghosts. The same fact, in hypnotism and hysteria, produces surprising phenomena. Movements, sensations, and more or less complex acts may be suggested to the hypnotized patient. Illusory sensations, and consequently hallucinations, can also be provoked. Like effects can be obtained without a real object, and by virtue of speaking alone, or