5. 4.
• X (March 13, 1720 – May 20, 1793), was a Swiss naturalist and
philosophical writer. His first published work appeared in 1745,
entitled Traité d'insectologie, in which were collected his various
discoveries regarding insects, along with a preface on the
development of germs and the scale of organized beings.
• In 1760 he described a condition now called X Syndrome,in which
vivid, complex visual hallucinations (fictive visual percepts) occur in
psychologically normal people. (He documented it in his 87 year old
grandfather,who was nearly blind from cataracts in both eyes but
perceived men, women, birds, carriages, buildings, tapestries and
scaffolding patterns.) Most people affected are elderly with visual
impairments, however the phenomenon does not occur only in the
elderly or in those with visual impairments; it can also be caused by
damage elsewhere in their optic pathway
