Page:Popular Science Monthly Volume 13.djvu/727

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HALLUCINATIONS OF THE SENSES.

and refuses it when it is given to him by one attendant whom he suspects of poisoning him, will take the same food from another attendant, of whom he has no suspicion, without tasting any poison—a proof how much the morbid idea perverts his taste. There is a form of insanity, known as general paralysis, which is marked by an extraordinary feeling of elation and by the most extravagant delusions of wealth or grandeur, and the patient who labors under it often picks up pebbles, pieces of broken glass, and the like, which he hoards as priceless jewels: there is another form of insanity known as melancholia, which is marked by an opposite feeling of profound mental depression and corresponding gloomy delusions, and the patient who labors under its worst form sometimes sees devils in those who minister to him, hears jeers in their consoling words, and imagines torments in their anxious attentions. In each case the hallucinations reflect the dominant morbid feelings and ideas.

A second way in which hallucinations appear to originate is directly in the organ of sense or in its sensory ganglion, which for present purposes I may consider as one. Stimulation of the organ or of its ganglion will undoubtedly give rise to hallucination: a blow on the eye makes a person see sparks of fire or flashes of light, a blow on the ear makes his ears ring; in fact, any organ of sense, when irritated either by a direct stimulus to its nerve-centre, or by a perverted state of the blood which circulates through it, will have the same sensation aroused in it, no matter what the stimulus, as is produced by its natural stimulus. We can irritate the sensory ganglion directly by introducing certain poisonous substances into the blood, and so occasion hallucinations: for example, when a person is poisoned with belladonna (deadly nightshade) he smiles and stares and grasps at imaginary objects which he sees before him, and is delirious. Other drugs will produce similar effects. A French physiologist has made a great many experiments in poisoning dogs with alcohol by injecting it into their veins, and he has found that he can arouse in them very vivid hallucinations: the dog will start up, perhaps, with savage glare, stare at the blank wall, bark furiously, and seem to rush into a furious fight with an imaginary dog; after a time it ceases to fight, looks in the direction of its imaginary adversary, growling once or twice, and settles down quietly.

The hallucinations which occur in fevers and in some other bodily diseases evidently proceed directly from disorder of the sensory centres, and not from the action of morbid idea upon sense; for we have seen that before they are fixed the intellect struggles against them successfully and holds them in check. A well-known and instructive instance of hallucinations, due to bodily causes, and which did not affect the judgment, is that of Nicolai, a bookseller of Berlin, who, being a person of great intelligence, observed his state carefully and has given an interesting account of it. He had been exposed to a succession of severe trials which had greatly affected him, when, after an incident