The article discusses the theory of degeneration as presented in the works of Benedict-Augustin Morel, situating it within the scientific and cultural context of its day. It underscores the roles played by the notions of heredity and environment in grounding this theory and how it related to the mid-nineteenth century French understanding of psychiatric medicine. It also explores the ramifications of this theory, particularly the works of Valentin Magnan, with the ultimate progressive transition from the notion of degeneration to that of degenerate. Other points of analysis include French psychiatry's concepts of imbalance and constitution and German psychiatry's concept of endogeneity as heirs to degeneration in twentieth-century psychiatry, as well as the Neo-Lamarckian appropriation of this debate in Brazil.
degeneration; degenerate; Bénedict-Augustin Morel (1809-1873); Valentin Magnan (1835-1916); Brazil