The most important consequence of having a strongly developed ultra-marginal life of this sort is that one's ordinary fields of consciousness are liable to incursions from it of which the subject does not guess the source, and which, therefore, take for him the form of unaccountable impulses to act, or inhibitions of action, of obsessive ideas, or even of hallucinations of sight or hearing. The impulses may take the direction of automatic speech or writing, the meaning of which the subject himself may not understand even while he utters it; and generalizing this phenomenon, Mr. Myers has given the name of automatism, sensory or motor, emotional or intellectual, to this whole sphere of effects, due to 'uprushes' into the ordinary consciousness of energies originating in the subliminal parts of the mind.
The simplest instance of an automatism is the phenomenon of post-hypnotic suggestion, so-called. You give to a hypnotized subject, adequately susceptible, an order to perform some designated act—usual or eccentric, it makes no difference—after he wakes from his hypnotic sleep. Punctually, when the signal comes or the time elapses upon which you have told him that the act must ensue, he performs it;—but in so doing he has no recollection of your suggestion, and he always trumps up an improvised pretext for his behavior if the act be of an eccentric kind. It may even be suggested to a subject to have a vision or to hear a voice at a certain interval after waking, and when the time comes the vision is seen or the voice heard, with no inkling on the subject's part of its source. In the wonderful explorations by Binet, Janet, Breuer, Freud, Mason, Prince, and others, of the subliminal consciousness of patients with hysteria, we have revealed to us whole systems of underground life, in the shape of memories of a painful sort which lead a
