Of course, as a rule, hallucinations are an index of mental disturbance. No matter how apparently sane the patient, this must be the first thought and must be carefully excluded before proceeding with the case. The subject of hallucinations is larger than that, however, and it is a mistake to brush it aside in every case as if it were either very serious or of no importance and that in either case nothing can be done to relieve solicitude about it. Physicians can often do much, first to prevent hallucinations by getting at the physical causes of them; second, to prevent them from disturbing patients seriously by showing them how common are such experiences and by indicating their possible physical significance; third, by securing such mental discipline and control as will render their recurrence much less frequent; and, fourth, they can make the almost inevitable unfavorable effect upon the mind of the patient and then reflexly upon his body, much less than it would otherwise be, by sympathetically discussing and entering into the details of them enough, at least, to explain their significance or throw some light on their origin in physical conditions.
Hallucinations of vision, the seeing of things and persons that have no real existence at the time and place they are seen, are usually considered to be rather uncommon and to occur only in those whose mentality is seriously disturbed. Careful studies of the subject, however, show that at least one in ten [{605}] of educated people consulted have had some hallucinations of vision. Either they have wakened up, or they have dreamt that they waked in the early morning, and have seen some one whom they knew, but knew to be at the moment at a distance, standing near them. Such visions have gradually faded away or suddenly disappeared. Occasionally these persons have in full light had some appearance, wraithlike or otherwise, some manifestation that appeals to vision, yet that they knew at the time or learned afterwards was non-existent.
Many people are backward about confessing that they have had such experiences, for they fear that it will make them ridiculous or even cause them to be suspected of disturbed mentality. Just as soon as it is made clear to them that their admissions will be taken as evidence for a phenomenon to be discussed seriously, many more than would otherwise be thought confess to such hallucinations. Most of these, it may be said at once, are quite sensible people, a great many of them belong to the educated classes; all of them are trustworthy witnesses as far as good will goes, and the circumstances of their hallucinations are such in many cases that there cannot be a mere mistake, or error of judgment.
The frequency with which hallucinations occur may be appreciated from the investigation made some years ago at the instance of the Congress of Experimental Psychology. The following question was put to 17,000 persons, mostly residents of Great Britain, and answers received: "Have you ever, when believing yourself to be completely awake, had a vivid impression of seeing or being touched by living beings or inanimate objects, or of hearing a voice, which impression, so far as you could discover, was not due to any external physical cause?" The answers showed that 655 out of 8,372 men and 1,029 out of 8,628 women had experienced a sensory hallucination at some time in their lives. Some of them had had a number of them. That is, one out of ten in the educated classes has had some hallucination, and nearly one out of every eight women. An analysis of the statistics, however, brings out some interesting suggestions. There were nearly twice as many hallucinations related as having occurred during the year before the question was asked as in the preceding years. There was a definite reduction in the number that had occurred in all the preceding years, except the fifth and tenth, and these were evidently due to uncertainties of memory, so that five- and ten-year periods seemed about the length of time that had passed since the event.
It is evident then that in spite of the fact that an hallucination would seem to be very important and surely startling enough to be well remembered, it is yet easily forgotten, since even a year's interval made so much difference in the number that were remembered. The committee, after considering this easy forgetfulness in the matter, considered that to arrive at the actual total of visual hallucinations experienced by this group of 17,000 persons during the ten-year period in question, the numbers in the table should be multiplied by four. That means that probably very nearly one in three people have had an hallucination of some kind within ten years. The great majority of the visual hallucinations consist of apparitions of human figures. Other forms that are seen are so few, as Mr. Podmore has insisted in his "Telepathic Hallucinations, The New View of Ghosts," [Footnote 45] that they are almost negligible. A frank [{606}] discussion of these details with a person who is much disturbed by having experienced an hallucination is the best possible remedy for the physical and mental disturbance that may result.
[Footnote 45: The Twentieth Century Science Series, New York, 1910.]
Sir Francis Galton, well known for his investigation of many subjects and who may well be called the father of biometrics or statistical biology, in his "Memories of My Life" [Footnote 46] tells of his own investigations of the visions of sane persons. The fact that he delivered a lecture on this subject at the Royal Institution of London shows how seriously his studies were made and how much value scientists placed on them. Galton's well-recognized training in the careful weighing of evidence and his ability to strip phenomena of everything that might divert their significance from what they really were, add to the worth of his conclusions. Those who care to study the subject further will find his discussion in the Proceedings of the Royal Institution (London, 1882).
[Footnote 46: New York, 1909.]
There are few people beyond middle age who have not had one or more curious experiences in the matter of visions or appearances. Mostly these have been vague and have not proved a disturbing element in the minds of the subjects. Many more than are thought, however, have seen visions vividly and with a detail that makes it almost impossible for them to believe that what they saw was merely an externation of ideas already in their mind. In this matter it must not be forgotten that the dreams of many people, especially nervous people, often present themselves with marvelous vividness of detail. They see people or places in their dreams and reason about them quite rationally. Occasionally a dream will bring back details that have been forgotten. The dreaming state seems in some people to have wonderful power over the subconscious. Things that are not remembered at all in the waking state sometimes come back in dreams, and only then are recalled by the individual as representing past events in his life. He is apt to wonder where the details could possibly come from, since he had before no conscious memory of them. This same thing holds for the day-dreams or sudden visual appearances that come when the attention has been wrapped in something else.
A typical example of such visual hallucinations is the following incident told by a prominent London physician of himself: