William Alexander Hammond

“ The reiteration in the ears, during every minute of the day, of the command to jump into the river, to plunge a convenient knife into the heart, and so on, day in and day out, is calculated to shake the power of control of the strongest-minded. ”

“ Illusions of sight often relate merely to the size of objects. Thus, a young lady who had overtasked herself at school saw everything of enormous size at which she looked. The head of a person seemed to be several feet in diameter, and little children looked like giants. So far as her own person was concerned there were no illusions. ”

“ Mental excitement will cause a like effect in some persons. I am acquainted with a gentleman who can not participate in any engrossing conversation without having a bitter taste developed in his mouth. ”

“ Hallucinations of hearing are more common than those of any other of the special senses, and, according to my experience, are more apt to lead to further mental disorder. Far more people kill themselves under the influence of hallucinations of hearing than from those of all the other senses combined. ”

“ Hallucinations of the sense of touch are, on the other hand, very frequently met with. Sensations apparently not based on any real impression are experienced in various parts of the body. It is difficult, however, to discriminate between illusions and hallucinations of touch.
Occasionally persons have the power of voluntarily producing hallucinations. A practice fraught with danger, for the time is apt to come at which they can not get rid of their false perceptions. ”

“ Children are very liable to be subject to hallucinations, and frequently give circumstantial accounts of incidents which they believe have occurred to them, of voices they have heard, etc. It is often impossible for them to discriminate between the true and the false, and I am afraid they are often punished for lying by ignorant parents, when they have told nothing but what they have had the evidence of their senses for believing. ”

“ In my opinion, they are the cause of the hallucination becoming a delusion, and, indeed, between a psychic hallucination and a delusion there is very little difference. The former can not exist without the involvement of the intellect. ”

“ The difference between illusions and hallucinations can be recognized without difficulty, for the latter are entirely cerebral in origin, and do not require, as do the former, a material basis. They can not be produced by any defects or derangements of the sensory organs, or by any external circumstances tending to interfere with the normal action of these organs. ”

“ As hallucinations of sight often exist while the eyes are closed, or in persons who are totally blind, so hallucinations of hearing continue though the ears be stopped, or originate in persons who are entirely deaf. ”

“ There is some evidence to show that the thalami optici are the centers for all real perceptions, and that hence they are the organs, which, through their disease, give rise to all centric illusions and hallucinations. ”

“ At last she lost control of the operations, and became constantly subject to hallucinations of sight and hearing.
Although no one presumes to question the honesty of Jerome Cardan, or of Swedenborg, it is probable that their visions were also induced by intense mental concentration. In some persons very slight thought is sufficient to cause hallucinations of great distinctness.
The causes of central illusions and hallucinations are generally to he found in derangements of some kind in the blood circulating in the brain. ”

“ After the first day the figure of the deceased person no longer appeared, but its place was supplied by many other phantoms, sometimes representing acquaintances, but mostly strangers. After about four weeks he began to hear them talk. The application of leeches to the arms relieved him promptly of his hallucinations. ”