Page:Popular Science Monthly Volume 22.djvu/781

Rh perceptions—illusions and hallucinations. Uncomplicated illusions are rare; still there is no doubt that there are illusions not the results of disease in the organs of sense or of circumstances unfavorable to exact perception, but which are due to a morbid condition of the perceptional ganglia, and the unreal nature of which is clearly recognized by the individual.

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. Her own hands appeared of the natural size, but those of other people seemed to be of enormous proportions. Sauvages refers to a case in which a young woman, suffering from epilepsy, had the illusion of seeing objects greatly magnified. A fly seemed to her to be as large as a chicken. In the case which came under my observation, the unreal character of the perception was fully recognized, and hence the intellect was not involved.

Morbid illusions of hearing, unaccompanied by other evidences of mental derangement, are not very common. One case only has come under my observation. It was that of a gentleman to whom the ticking of a clock was resolved into articulate words. Generally the expressions were in the form of commands. For instance, if at dinner, they would be, "Eat your soup!" "Drink no wine!" and so on. One day he made the discovery that, if he closed the right ear firmly, the illusion disappeared; but, if the left ear were closed, the words were still distinctly heard. It was hence clear that the center for hearing on the right side was the one affected, and that that on the left side was normal. For a long time this gentleman resisted accepting any of these illusions as facts, but after a time he began to be influenced by them to the extent of regarding them as guides. Eventually he put clocks in every room in his house, and professed to be governed altogether by the directions they gave him.

Illusions of touch, as Michea says, may relate to temperature, movement, weight, and the character of surfaces. Thus, to some patients, substances that are hot feel cold, and vice versa; others feel the things on which they sit or lie glide from under them. Illusions of a general character as regards the whole body are quite common—giving the sensation of extreme weight or lightness, or as if the body were immensely lengthened or shortened.

As regards frequency, illusions of the sense of touch occupy the front rank; next are those of sight, and next those of hearing. Illusions of taste and of smell, except with persons who are otherwise insane, are not common. A few instances of the latter, however, have occurred within my personal experience. To one of these, a lady, everything she put into her mouth tasted like cauliflower; in another