cortical layers are inactive, the mere flashing of a light before the eyes of the sleeper is likely to produce complex dreams of fire and an unsystematized comparison of concepts of some intricacy.

There are some rules which govern the occurrence of peripheral visual hallucinations, and one is that they are more pronounced when the eyes are closed and in the dark, and they are more or less influenced by the condition of the ocular muscles generally. According to Kirchhoff loc. cit., p. 48): "If the sensorial deception develops in one eye alone, the possibility of distinguishing it from a unilateral hallucination which has developed centrally is to be sought in the fact that the central development gives rise to much more complicated phenomena." The explanation of a unilateral hallucination would naturally lead us to consider the physiological pathology, and to look for some affection of the occipital lobes. It has been pointed out that in paretic dementia in which the frontal lobes are most frequently affected, there are seldom hallucinations; but in those cases where this symptom has occurred the occipital lobes have been found to be diseased.

Unilateral hallucination of vision can be explained by some disease of the optic commissure, or of the nerve nuclei of one side of the brain. Auditory hallucinations, which may be of a very simple kind, or, on the other hand (as in the case of optical perversion), may form the basis of mental mistakes, are varied in their causation and occurrence. They perhaps more frequently have a deeper and more alarming significance than the others, are not so easily corrected, and are more general in occurrence than any other hallucinations. They usually consist of the recognition of the sound of imaginary voices and the repetition of many ordinary sounds. A distinctly insane hallucination of hearing has nearly always valuable diagnostic significance, for the reason that it indicates a more general derangement than those of the other senses. person may readily have such a sane hallucination as hearing an imagi nary voice, as the result, possibly, of an irritation of the middle ear; but the insane individual expresses his fear of the sounds of voices speaking through a telephone, the register, or cracks in his room; or, in a more disorderly condition, it is the figures in the pictures upon the wall who are addressing him.

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Auditory hallucinations that convey no suggestion of insanity, like all other ordinary false perceptions, are nearly always immediately removed, are recurrent in the original form, and, of course, are not associated with other evidences of derangement. The auditory hallucinations of the insane patient form the basis of communications from divine personages, from invisible friends or others, who command him to perform various acts, and he cannot be convinced of his error even when his environment is changed and certain objects are removed which facilitated the creation of the hallucination itself.

There is a light grade of purely mental auditory hallucinatory disturbance that I have seen, and it is in some measure hysterical, the full image being called up at will, and the patient's declaration and behavior doing away with any real supposition that the ear or eye is at fault. I have recently seen a case of this kind, where the suspicion that an auditory hallucination existed was at first very strong, but frequent interviews convinced me that when the patient turned in one direction and addressed an imaginary person, such an act was led up to by an incoher

ent conversation, in which the response to the imaginary mandate was prompted by a previous train of thought; and when I asked her if the persons she addressed were near her, she replied, "No," but that she was talking to them in the spirit. The consequences of hallucinatory mandates and subsequent delusions are apt to sometimes be serious, and those cases where patients refuse food and drink because they are told to do so by imaginary persons are often obliged to submit to compulsory feeding, or, if this is not done, death by starvation ensues.

Hallucinatory voices may be bilateral or unilateral, external or internal, and are not so common at night as in the daytime when the patient. is awake.

Olfactive hallucinations are exceedingly rare, and may, like the others, have a local or a central basis. Perversions of both taste and smell, therefore, may result from some actual local condition, such as decomposition of epithelium in the mouth, bad taste, offensive discharges, etc. Sometimes these conditions lead to well-marked delusions, which are amplified usually in the direction of the horrible.

The odor of decayed matter suggests that of a dead body, while refusal to eat is the result of a delusion of poisoning. There are a class of purely central hallucinations of this character which owe their origin to some disease of the olfactory nerve itself, or probably to the uncinate gyrus. Such a case I have elsewhere reported, where occasionally hallucinatory perception of the odor of smoke was a symptom, and a subsequent autopsy revealed extensive disease of the region above mentioned. However, the patient is nearly always able to recognize the source of his. trouble; but when he does not, we may then account for such a perversion as an incident due to insanity.

What are known as hallucinations of feeling, and what are really perverted or false perceptions of the skin and its appendages, the visceral organs, or an alteration of what is known as the muscular sense, are symptoms both of the lighter psychoses as well as of the graver forms of mental disease, and, like the other hallucinations previously mentioned, may not at times be attended by any considerable intellectual impairment. They play an important part in hypochondriasis, and in that affection of limited intellectual disturbance known as paranoia, where one or two dominant illusions exist. Their range, however, is usually very wide.

Disturbances of muscular sense lead to a variety of perverted perceptions, individuals declaring that they have been deprived of certain members, or that one part of the body or the other is absent. A common example of this form of hallucination is that in which the individual who has undergone amputation declares that he feels the presence of the lost limb. Sometimes these hallucinations are pleasurable and expansive, though very often they are associated with mental distress and not unrarely lead to suicide. They very often cause the victim to declare that he is being subjected to some occult influence, that he is being mesmerized, or is the subject of punishment inflicted by others. Of course, under these circumstances, the hallucination is the basis of a delusion.

Sensorial hallucinations sometimes have an important significance in the form of sexual perversion.

Curious cases are recorded where women prefer the most absurd charges of assault, or imagine themselves impregnated or sexually de

formed, as the result of sensorial hallucinations. I have seen several men who through such a deranged mental state believed themselves pregnant.

As before stated, the expression of hallucinations of all kinds is very irregular, and does not necessarily indicate insanity. We find everywhere in literature instances of false perception, some of which are historical and familiar. Lombroso (The Man of Genius, London, 1891, pp. 56, 57) has collected numerous examples, as has also Brierre de Boismont. Brutus Cæsar and Napoleon had simple hallucinations, those of the latter being evidently due to some circulatory disturbance incident to exhaustion. Shelley thought he saw a child arise from the sea and clap its hands. Bunyan heard voices. Byron imagined that he was haunted by a specter. Dr. Johnson distinctly heard his mother call him "Samuel," although she was not present. Goethe saw his own image coming to meet him, and Van Helmont declared that he had seen his own soul in the form of a brilliant crystal. "When Oliver Cromwell was lying on his bed, kept awake by extreme fatigue, the curtain opened, and a woman of gigantic proportions appeared and announced that he would be the greatest man in England." Some of these cases probably belonged to the condition of semi-consciousness or troubled sleep. Others were due to fatigue, and still others to genuine mental aberration. Dr. Johnson, as is well known, presented a form of mental disorder which is now recognized as folie du doute, which however is not usually accompanied by hallucinations.

The hallucinations of acute alcoholism, as well as those due to Cannabis Indica, opium, and numerous derivatives of the Solanaceae-belladonna, hyoscyamus, etc.-are examples of exhaustive or toxic causation.

It is possible to induce various hallucinations by hypnotic suggestion, and they are by no means uncommon accompaniments of those dramatic hysterical states which are so commonly witnessed in France. In women they not unrarely have a sexual relation.

Hallucinations are found Alone and Together. It is rare for a single hallucination to last for any length of time, except possibly when it is of an auditory character, and in this case such an occurrence is reasonable when we consider how important and general is the excitement which stimulates the word-symbol centers, that play so important a part in the operation of all thought. So far as the connection of hallucinations with particular forms of insanity is concerned, it may be said that they are more frequently met with in acute mental disease.

In primary delusional insanity or paranoia, in confusional insanity, in conditions where the nerve centers are poisoned, especially in alcoholic insanity, in the insanity which is the result of fevers, we find hallucinations to be a common symptom, and they are always increased or developed by seclusion. Hallucinations are not only a common result of solitary confinement, but are expressed at night, when the patient is alone, and when sleep is fitful, and the insane person indulges in noisy outbreaks. As Lewis (A Text-book of Mental Diseases, p. 167) has pointed out, such individuals are benefited by removal to an associate dormitory. "Such hallucinations," says he, "often peculiarly vivify and fascinate the mental vision, and, according to their nature, call forth corresponding results. The patient may be passionate, wild, threatening, and defiant, shouting an alarm for succor; joyous, exultant, or in a boisterous merriment. Every phase of emotional life may present itself as the hallucinations vary and he enacts his little drama alone. . . . In general

paralysis these nocturnal orgies are frequent, noisy, restless, with or with out hallucination, accompanying the latter stages of most cases."

A table prepared by Dr. Edward B. Lane is reproduced, which will be of service in showing not only the kind and extent of hallucinations, but the forms of insanity in which they appear. (Boston Medical and Surgical Journal, vol. cxxv., No. 11, p. 268.)

The appearance of hallucinations in primary delusional insanity has been referred to, and in such a condition they are usually persistent, and form a basis of that variety known as the sensorielle Verrücktheit, in which some delusions owe their origin to perverted perceptions originating in the skin or the visceral organs. In other cases, delusions of persecution and suspicion spring directly from hallucinations of hearing and seeing.

ILLUSIONS.

An illusion is a distorted perception of an objective reality; in other words, it is the false perception of something that has an existence.

Illusions are like hallucinations in their classification-they may be of various kinds, and are due largely to local disease; and while sometimes as elements of insanity they are by no means so important as the forms of false perception just described, which have no objective basis, may originate more or less stubborn delusions, or, on the other hand, may often be easily corrected by their possessor.

The distinction between an illusion and hallucination may be illus*And touch.

trated as follows: if a person looks at a tree and sees two, it is an illusion; if he declares that he sees a tree where none exists, it is an hallucination. If he misinterprets the sound of a ringing bell, it is an illusion; if he says that he hears à bell when none has rung, it is an hallucination. Psychologically, the processes consist in the inability to comprehend the nature of a physical impression, an imperfect concept being the result of a false perception upon which an imperfect judgment has been passed.

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In an hypnotic condition or one of exaggerated receptivity, an individual is very apt to make illusional mistakes in identity, which would be out of the question under other circumstances; so that it is not unusual for insane people to eventually have distinct delusions of personality, which are due to their false appreciation of the figure and form of some person whom they have possibly never seen before. Like hallucinations, illusions are common in alcoholic insanity, as well as in paranoia and confusional insanity, and sometimes exist as a symptom of paretic dementia.

DELUSIONS.

A delusion is a false belief, and may be regarded as sane and insane. Under the former head are grouped all forms of erroneous or unusual beliefs which many individuals entertain whose mental integrity is unquestioned. These latter may be simply the offspring of ignorance or prejudice or misinformation, and unless they be the fruit of religious or other dogmas may be easily removed by sufficient evidence. When beliefs are held which to many seem unreasonable, but are nevertheless shared by a sufficient number of people to be simply matters of faith, they still need not be the product of diseased reasoning, though oftentimes they are eccentric and troublesome to the world at large. No one would think of questioning the mental health of the large religious sects that believe in the immaculate conception or the miracles of Roman Catholicism, the doctrine of Swedenborgianism or spiritualism, any more than they would the sincerity of a great majority who hold to any other faith the elements of which are more or less inexplicable. It is, however, when extravagant belief obtains such complete possession, or is connected with clearly erratic behavior, that our doubts of the subject's sanity arise. So long as the spiritualist has or pretends to have communication with visible spirits, and so long as his hallucinations or illusions or delusions do not tincture his conduct in a way that makes him a nuisance to his fellows, the law concerns itself but little; but when, as the result of a delusion, a crime is committed or a foolish business act is consummated, we more seriously question his responsibility. The law is exceedingly merciful, if not lax, in its attitude toward such individuals, and is disposed to accept excuses that may be offered as a defense. I can recall a case where a large amount of money had been left by an eccentric Frenchman to a philanthropic society for the suppression of cruelty to animals, and for the special care of cats.* His will was contested, and besides peculiarities of manner, it was the subject of contest by reason of this seeming mark of insanity. It, however, transpired that the testator had been for years a consistent believer in metempsychosis, and was, naturally, anxious that his transferred soul should be well taken care of after his demise.

* The Bonard Will Case.