From Libidines nefandæ to sexual perversions

A conceptual evolution is traceable from early modern classifications of libido nefanda (execrable lust) to early nineteenth-century allusions to 'perversion of the sexual instinct', via pluralizing notions of coitus nefandus/sodomiticus in Martin Schurig's work, and of sodomia impropria in seventeenth- through late eighteenth-century legal medicine. Johann Valentin Müller's early breakdown of various unnatural penchants seemingly inspired similar lists in works by Johann Christoph Fahner and Johann Josef Bernt, and ultimately Heinrich Kaan. This allows an ante-dating of the 'specification of the perverted' (Foucault) often located in the late nineteenth century, and appreciation of pygmalionism and necrophilia as instances of 'perverted sexual instinct'. In this light, Kaan's early psychopathia sexualis was less innovative and more ambivalent than previously thought.