A term dating from the Mesmeric age and denoting the
power of somnambules to see their own organs and give a description
of their state. The word was coined by neurologist
Charles Féré. He applied it to the vision his patients saw of
their double in a morbid state. This is external autoscopy, as
contrasted by Baron du Potet to internal autoscopy selfdiagnosis
in a trance. Dr. Sollier wrote a monograph, Les Phénomènes
d’autoscopie (Paris, 1903), on the subject.