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 jects sometimes double, and at others upside down, suddenly showed signs of cerebral congestion, and threatened apoplexy. By proper treatment, however, he was saved for a time from the latter catastrophe, but he became permanently afflicted with strabismus, or squinting, and he suffered from a singular hallucination. His eyelids would contract, and his eyeballs would roll from side to side at more or less distant intervals. On these occasions he imagined he saw the figures of different persons that he knew moving about, and would even follow them outside his door into the other rooms of the house. He was perfectly aware that these appearances were merely the effect of the imagination, but this did not in any way detract from their appearance of reality. The man afterwards died from an attack of apoplexy.

The following examples are also cases of singular optical deception, some of them being so extraordinary as to trench upon the supernatural, and in the days of ignorance would have given those who were their victims the character of unearthly personages.

A certain English painter, who in some sort inherited the palette of Sir Joshua Reynolds, and believed himself superior in many respects to the great master, used to boast that in one year he painted over three hundred portraits, large and small. This fact seemed to Wigan a physical impossibility, and he questioned him closely as to the secret of his astonishing rapidity of execution, for he never required more than one sitting from his patrons. Wigan states that he saw him paint a miniature of a well-known personage in eight hours, which was incomparable in its fidelity to nature and finished execution. Wigan asked him to give him some details of the method he adopted, and he gave him the following answer: "When a sitter presents himself, I look at him attentively for half an hour, sketching the outlines of his features on my canvass during the