Carlos López-Beltrán, Haereditarii morbi in Early Modern Europe

According to P. Laín Entralgo, the old mythical concept of diseases that run in families by some unfathomable plan, received a physiological underpinning in the Hippocratic corpus, with the notion of ‘family’ (katà génos) or congenital (syngenés) diseases. As shown by M. van der Lugt, the contemporary notion of hereditary disease derives most likely from medieval Latin translations of treatises in Arabic, especially Avicenna’s Canon. In the Middle Ages, the notion of hereditary disease became more sophisticated and went well beyond a simple reference to family charac- ter. Medieval physicians proposed distinctions and criteria which were taken up and further developed during the first centuries of the Early Modern Period. From the last decade of the 16th century on, the number of treatises on hereditary disease grew considerably, as several European physicians devoted themselves to trying to define, within the framework of the debate about Hippocratic solid-humoral physiology, the characteristics of diseases that are truly hereditary, in the sense of being transmitted from parents to children through reproduction. This article examines and analyses these developments, which served as the basis of our current concept of biological heredity.