Daniel Sennert on Disease and the Ontological Inversion of Generation.

This article examines how Daniel Sennert (1572-1637) reconciles Aristotelian hylomorphism with iatrochemical insights through the ontological relation between generation and disease. It focuses on the diseases Sennert models on generation, those carried by semina morborum, rather than the ordinary disorders of humoral intemperance. First, it identifies the ontological architecture grounding the inversion between generation and pathology: Sennert's rejection of the eduction of forms, his plurality of substantial forms organised through the essential/accidental distinction, and his corpuscular framework. Second, it traces how Sennert selectively appropriates Severinus's transplantatio (the transfer of seminal principles between substrates) and transforms his formula of opportunitas (the condition under which a seed may take root). Reproducing it almost verbatim, Sennert shifts its modality, strips its Paracelsian metaphysics and regrounds the enabling condition of disease in the failure of the balsamum innatum, an inborn restorative power. Third, it follows the inversion into Sennert's corpuscular account of contagion and into three clinical cases (rabies, epilepsy, and syphilis) that trace a hierarchy of seminal causation. Although Sennert withholds the term transplantatio from his pathology, the mechanism persists without formative power: insertion without formation, rooting without propagation, affinity without perfection.