University of Virginia Library

Section 104. (b) Hallucinations and Illusions.

The limits between illusions of sense and hallucinations and illusions proper can in no sense be definitely determined inasmuch

as any phenomena of the one may be applied to the other, and vice versa.[1] Most safely it may be held that the cause of illusions of sense lies in the nature of sense-organs, while the hallucinations and illusions are due to the activity of the brain. The latter are much more likely to fall within the scope of the physician than sense-illusions, but at the same time many of them have to be determined upon by the lawyer, inasmuch as they really occur to normal people or to such whose disease is just beginning so that the physician can not yet reach it. Nevertheless, whenever the lawyer finds himself face to face with a supposed illusion or hallucination he must absolutely call in the physician. For, as rarely as an ordinary illusion of sense is explicable by the rules of logic or psychology, or even by means of other knowledge or experience at the command of any educated man, so, frequently, do processes occur in cases of hallucination and illusion which require, at the very least, the physiological knowledge of the physician. Our activity must hence be limited to the perception of the presence of hallucination or illusion; the rest is matter for the psychiatrist. Small as our concern is, it is important and difficult, for on the one hand we must not appeal to the physician about every stupid fancy or every lie a prisoner utters, and on the other hand we assume a heavy responsibility if we interpret a real hallucination or illusion as a true and real observation. To acquire knowledge of the nature of these things, therefore, can not be rigorously enough recommended.

Hallucination and illusion have been distinguished by the fact that hallucination implies no external object whatever, while in illusion objects are mistaken and misinterpreted. When one thing is taken for another, e. g., an oven for a man, the rustle of the wind for a human song, we have illusion. When no objective existence is perceived, e. g., when a man is seen to enter, a voice is heard, a touch is felt, although nothing whatever has happened, we have hallucination. Illusion is partial, hallucination complete, supplementation of an external object. There is not a correct and definite difference between illusion and hallucination inasmuch as what is present may be so remotely connected with what is perceived that it is no more than a stimulus, and thus illusion may be turned into real hallucination. One authority calls illusion the conception of an actually present external event which is perceived by the peripheral organs in the form of an idea that does not coincide with the

event. The mistake does not lie in the defective activity of the senses so much as in the fact that an apperceptive idea is substituted for the perceptive view. In hallucination every external event is absent, and hence, what is seen is due to a stimulation of the periphery. Some authorities believe hallucination to be caused by cramp of the sensory nerve. Others find illusions to be an externally stimulated sense-perception not corresponding to the stimulus, and still others believe it to be essentially normal. Most human beings are from time to time subject to illusions; indeed, nobody is always sober and intelligent in all his perceptions and convictions. The luminous center of our intelligent perceptions is wrapped in a cloudy half-shadow of illusion.

Sully[2] aims to distinguish the essential nature of illusion from that characterized by ordinary language. Illusion, according to him, is often used to denote mistakes which do not imply untrue perceptions. We say a man has an illusion who thinks too much of himself, or when he tells stories otherwise than as they happen because of a weakness of memory. Illusion is every form of mistake which substitutes any direct self-evident or intuitive knowledge, whether as sense-perception or as any other form.

Nowadays the cause of hallucination and illusion is sought in the over-excitement of the cerebro-spinal system. As this stimulation may be very various in its intensity and significance, from the momentary rush of blood to complete lunacy, so hallucinations and illusions may be insignificant or signs of very serious mental disturbances. When we seek the form of these phenomena, we find that all those psychical events belong to it which have not been purposely performed or lied about. When Brutus sees Cæsar's ghost; Macbeth, Banquo's ghost; Nicholas, his son; these are distinctly hallucinations or illusions of the same kind as those "really and truly" seen by our nurses. The stories of such people have no significance for the criminalist, but if a person has seen an entering thief, an escaping murderer, a bloody corpse, or some similar object of criminal law, and these are hallucinations like classical ghosts, then are we likely to be much deceived. Hoppe[3] enumerates hallucinations of apparently sound (?) people. 1. A priest tired by mental exertion, saw, while he was writing, a boy's head look over his shoulder. If he turned toward it it disappeared, if he resumed writing it reappeared. 2. "A thoroughly intelligent"

man always was seeing a skeleton. 3. Pascal, after a heavy blow, saw a fiery abyss into which he was afraid he would fall. 4. A man who had seen an enormous fire, for a long time afterward saw flames continually. 5. Numerous cases in which criminals, especially murderers, always had their victims before their eyes. 6. Justus Möser saw well-known flowers and geometrical figures very distinctly. 7. Bonnet knows a "healthy" man who saw people, birds, etc., with open eyes. 8. A man got a wound in his left ear and for weeks afterward saw a cat. 9. A woman eighty-eight years old often saw everything covered with flowers,—otherwise she was quite "well."

A part of these stories seems considerably fictitious, a part applies to indubitable pathological cases, and certain of them are confirmed elsewhere. That murderers, particularly women-murderers of children, often see their victims is well known to us criminalists. And for this reason the habit of confining prisoners in a dark cell for twenty-four hours on the anniversary of a crime must be pointed to as refined and thoroughly mediæval cruelty. I have repeatedly heard from people so tortured of the terror of their visions on such days of martyrdom. Cases are told of in which prisoners who were constipated had all kinds of visual and auditory hallucinations and appeared, e. g., to hear in the rustling of their straw, all sorts of words. That isolation predisposes people to such things is as well known as the fact that constipation causes a rush of blood to the head, and hence, nervous excitement. The well-known stories of robbers which are often told us by prisoners are not always the fruit of malicious invention. Probably a not insignificant portion are the result of hallucination.

Hoppe tells of a great group of hallucinations in conditions of waking and half-waking, and asserts that everybody has them and can note them if he gives his attention thereto. This may be an exaggeration, but it is true that a healthy person in any way excited or afraid may hear all kinds of things in the crackling of a fire, etc., and may see all kinds of things, in smoke, in clouds, etc. The movement of portraits and statues is particularly characteristic, especially in dim light, and under unstable emotional conditions. I own a relief by Ghiberti called the "Rise of the Flesh," in which seven femurs dance around a corpse and sing. If, at night, I put out the lamp in my study and the moon falls on the work, the seven femurs dance as lively as may be during the time it takes my eyes to adapt themselves from the lamplight to the moonlight. Something similar

I see on an old carved dresser. The carving is so delicate that in dim light it shows tiny heads and flames after the fashion of the Catholic church pictures of "poor souls," in purgatory. Under certain conditions of illumination the flames flicker, the heads move, and out of the fire the arms raise themselves to the clouds floating above. Now this requires no unusual excitement, simply the weary sensing of evening, when the eyes turn from prolonged uniform reading or writing to something else.[4] It has happened to me from my earliest childhood. High bodily temperature may easily cause hallucinations. Thus, marching soldiers are led to shoot at non-existing animals and apparently-approaching enemies. Uniform and fatiguing mental activity is also a source of hallucination. Fechner says that one day having performed a long experiment with the help of a stop-watch, he heard its beats through the whole evening after. So again when he was studying long series of figures he used to see them at night in the dark so distinctly that he could read them off.

Then there are illusions of touch which may be criminalistically important. A movement of air may be taken for an approaching man. A tight collar or cravat may excite the image of being stifled! Old people frequently have a sandy taste while eating,—when this is told the thought occurs that it may be due to coarsely powdered arsenic, yet it may be merely illusion.

The slightest abnormality makes hallucinations and illusions very easy. Persons who are in great danger have all kinds of hallucinations, particularly of people. In the court of law, when witnesses who have been assaulted testify to having seen people, hallucination may often be the basis of their evidence. Hunger again, or loss of blood, gives rise to the most various hallucinations. Menstruation and hæmorrhoids may be the occasions of definite periodic visions, and great pain may be accompanied by hallucinations which begin with the pain, become more distinct as it increases, and disappear when it ceases.

It might seem that in this matter, also, the results are destructive and that the statements of witnesses are untrue and unreliable. I do not assert that our valuation of these statements shall be checked from all possible directions, but I do say that much of what we have considered as true depends only on illusions in the broad sense of the word and that it is our duty before all things rigorously to test everything that underlies our researches.