The hypnoidal state into which man is apt to fall so easily, is well adapted to fear suggestions, since the fear instinct and the impulse of self-preservation are present in the subconsciousness, exposed during trance states to all sorts of fear suggestions and superstitions. It is during these brief periods of primitive hypnoidal states that the animal is exposed to attacks of enemies whose senses become sharpened to detect the weak spots in the armor of their victims, immersed in the momentary rest of the hypnoidal state.

During these periods of repose and passivity or of sleep stage, the animal can only protect itself by all kinds of subterfuges, such as hiding in various inaccessible places, or taking its rest-periods in shady nooks and corners, or in the darkness of the night. Each hypnoidal period closely corresponds to the larval stage of the insect, reposing in its cocoon,—the most critical time of the insect organism, most exposed to the depredations of its enemies. And still the hypnoidal state is requisite[265] to the animal in order to restitute its living matter and energy which have been wasted during the active moments of its life activities. Hence the weakness of the animal depends on the very constitution of its organism.

The hypnoidal state, although absolutely necessary in the process of metabolism, is also the moment of its greatest danger, and the fear instinct is specially intense at the onset of that hypnoidal moment, the lowest point of the weakness of the organism. The animal, after taking all precautions, is finally paralyzed into temporary immobility at the risk of its own existence.

The fear instinct determines the nature and character of rest and sleep. The lower the animal, the scantier are its means of defense in the ceaseless struggle for its preservation. The simpler the animal, the greater and more numerous are the dangers menacing it with total extinction,—hence it must be constantly on its guard. A state of sleep such as found in the higher animals is rendered impossible. The sleep must be light, and in snatches, rapidly passing from rest into waking,—the characteristic of the hypnoidal state. The fear instinct is the controlling factor of sleep and rest. When we are in danger the sleep is light and in snatches, and we thus once more revert to an ancient form of rest and sleep.

The insomnia found in cases of neurosis is a reversion[266] to primitive rest-states, found in the lower animals. The insomnia is due to the fear instinct which keeps dominating the conscious and subconscious mental activities, a state which has prevailed in the early stages of animal life. That is why the sleep of neurotics is unrefreshing and full of dreams of dangers and accidents, and peopled with visions of a terrorizing nature. Hence the neurotic fear of insomnia which is itself the consequence of the obsession, conscious and subconscious, of the fear instinct.

In my work on sleep I was greatly impressed with the place fear holds in animal life existence. From the lowest representative, such as the insect to the highest, such as man, fear rules with an iron hand. Every animal is subject to cataplexy of fear and to the hypnoidal state itself, the consequence of fear-adaptations to the external conditions of a hostile environment. Cataplexy and the consequent hypnoidal state which paralyze the animal, depriving it of all defense, are grounded in the imperfections of living protoplasm.

Man is subject to the hypnoidal periods of primitive life. It is during those periods that the shafts of suggestion are most apt to strike his subconsciousness, divorced as it is during those moments from the nodding self consciousness. During these nodding moments of his life he is exposed to harmful suggestions, since they are apt to arouse the[267] fear instinct, the most sensitive of all human instincts. It seems as if the fear instinct is never fully asleep, and is the easiest to arouse. It seems to be watchful or semi-watchful during the most critical moments of man’s helplessness.

Fear of darkness and fear of invisible foes are specially strong in man, because of the deeply rooted fear instinct, but also because of his memories of accidents and dangers that have befallen him, and which may befall him. Man’s fears hang round dark places, gloomy corners and nooks, caves and forests, and more especially during the darkness and shades of night, appearing as treacherous visions and specters of lurking dangers. And still from the very nature of his being man must rest and sleep, hence the association of terrors with night time. He can only overcome his night terrors by living and sleeping in more or less secure corners, in the neighborhood of h............