[Deliria of metamorphosis]

Two of the most eminent 17th-century doctors, Sydenham and Willis, were led by their observations of melancholy people's relations with their bodies to elaborate a conception of the internal man. The present article uses their studies of hypochondria as a male form of hysteria to show their similarities and differences. Both doctors attempted to explain how strange ideas produce true sensations; but while Sydenham saves the individual's unity by supposing an internal double (a solution later developed by others, Cabanis in particular), Willis insisted on the difference between the metaphor enacted by the melancholic for himself and his healthy state. They represent two different ways of continuing the inheritance of Aristotelian mimesis.