William Alexander Hammond,
Popular Science Monthly
(1883)
“ THE simplest forms of insanity are those which consist merely of false perceptions, and they are not of such a character as to lessen the responsibility of the individual. There are two forms of false 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. ”

