Illusion

A species of mania, in which the sensibility of the nervous system is altered, excited, weakened, or perverted. The patient is deceived by the false appearance of things, and his reason is not sufficiently active and powerful to correct the error; and this last particular is what distinguishes the sane from the insane. Illusions are not unfrequent in a state of health, but reason corrects the errors, and dissipates them. A square tower, seen from a distance, may appear round, but, on approaching it, the error is corrected. A distant mountain may be taken for a cloud, but as we approach we discover the truth. tion and a closer examination soon destroy this illusion. An insane individual is mistaken on the qualities, connections, and causes of the impressions he actually receives, and he forms wrong judgments as to his internal and external sensations; and his reason does i. it correct the error.

1 Beck, Med. Jur. 538; Esquirol, tom. 1, p. 202; Diet, des Sciences Medicales, "Hallucination."

See "Hallucination."

See Hallucination.