The sleep of the hallucinated is generally short, and almost always disturbed. Uneasiness and the distress which many persons feel in the dark, are greatly increased by apparitions. When these are of a terrible character, and the voices are threatening, the sufferers cannot enjoy a moment of repose; they shriek, fight, and exhibit evidences of a fearful conflict. When the cries of an insane person are heard in the silence of the night, it is certain that they are visited by hallucinations.

Disordered secretions offer nothing particular; occurring as they do in mental maladies, without being combined with hallucinations, they may be referred to those kinds of diseases.

Inquiries have latterly been instituted as to the time most favorable for the existence of hallucinations. Observation proves them to be most common in the evening, at night, and on going to rest, and that they obey a natural law, by which mournful ideas, uneasiness, fear, and terror are increased by solitude and darkness. But, although the greater number of hallucinations take place at night, many likewise occur during the day. We subjoin our observations on 144 cases.

The nature of the hallucinations does not appear especially to influence the period of their appearing.

It has, however, been noticed that some kinds of hallucinations appear indifferently day and night, asleep or awake, whilst others only come in the night.

M. Baillarger, in a memoir presented to the Royal Academy of Medicine,* entered into more circumstantial details, which we proceed to quote. Many of his deductions are verified by cases contained in this work.

1. The transition from sleep to waking, and from waking to sleep, exerts a positive influence on the production of hallucinations on subjects predisposed to insanity, previous to, in the commencement of, and during the progress of this malady.†

2. The mere act of lowering the eyelids is sufficient with some subjects, and even during their waking hours, to produce hallucinations of sight.

3. Hallucinations occurring in the intermediate state between waking and sleeping, howsoever short of duration, become most usually continued, and excite delirium.

4. Madness, in subjects already attacked by hallucinations at the moment of sleep, is quickly, and from its commencement, characterized by hallucinations.

5. Hallucinations occurring whilst awake, frequently become stronger at the moments of falling asleep and of awaking.

6. A fit of mania may follow immediately, and from the first access, hallucinations produced at the moment of falling asleep and of awaking.

7. Hallucinations of one sense occurring during waking hours, those of another sense may be produced at the moment of falling asleep.

8. The transition from waking to sleeping has much greater influence on the production of hallucinations, than the transition from sleeping to waking.

9. It is frequently after the suppression of a hemorrhage which has produced symptoms of congestion towards the head, that hallucinations have been produced at the moment of sleep.

10. The influence of the transition from waking to sleeping in the production of hallucinations, proves that at least in certain cases, it is a phenomenon purely physical, and demands purely physical treatment.

* Seance du 24 Mai, 1842. Memoires de l'Academie Royale de Medecine, t. xii. p. 476.

† This fact has already been noticed by Meister, in his Lettre sur 1'Imagination.

11. Hallucinations occurring in the intermediate state between waking and sleeping, above all in subjects predisposed to insanity, or who have already been deranged, are often the indications of impending delirium.

12. Hallucinations which precede sleep, and from their first appearance continue during several hours, are a cause of transient madness; and may excuse acts committed during the night by a subject who on the following day will be of perfectly sound mind.

Hallucinations in Dreams. - All the symptoms which we have enumerated may be reproduced in dreams; but, by reason of the nature of the impressions, they are often less vivid. False sensations do not always cease immediately on awaking in sane individuals, only they disappear in a longer or shorter time, whilst with deranged persons they continue.

The action of thought may be pursued in dreams, and events long passed be reproduced, works may be completed, and new combinations take place. The hallucination of a dream possesses at times a more astonishing character, since it appears to announce an event which is passing at the moment; the best explanation which can be given of this phenomenon is, that the preoccupations of the day have not been interrupted by sleep.

Hallucinations in dreams are often characterized by the presence of an incubus. This phenomenon was formerly very common in nocturnal hallucinations.

The hallucinations of sorcerers, in the Middle Ages, were very often universal; they saw, heard, felt, smelt, and tasted in common. This symptom also belongs to deranged and even sane persons, but is much less frequent. A more common event is to hear madmen reason during the day in accordance with their nightly hallucinations.

Finally, there are cases of somnambulism which present hallucinations similar to those of dreams. Many observations in these two classes prove that the will of man may be perverted, and he may be led into actions involving serious responsibility.

Symptoms of Illusions. - The symptomatology of illusions is so closely allied to that of hallucinations, as to need only a summary notice. The series of phenomena (called sensorial and intellectual) of hallucinations will bear the same explanation. The essential characteristic is the transformation which external objects, or those which exist out of the brain, undergo. A stranger may be transformed into a friend, a relative, a husband; or, a woman may become a man. The persons of their fellow-patients are, altered to those of other individuals. One person, on looking at himself in a mirror, was so strongly agitated that he rushed on his keeper and stabbed him with a knife. A descendant of the great Reformer, whom we attended, uttered a cry of horror; she had just seen her son in the glass, frightfully altered; this illusion was caused by the sight of herself. King Theodoric experienced the most bitter remorse at the sight of a fish that was served at table, which appeared to him to be the head of the Senator Symmachus, whom he had condemned to death.