Abstract
Intermittent fever is a historical diagnosis with a contested meaning. Historians have associated it with both benign malaria and severe epidemics during the Early Modern Era and early nineteenth century. Where other older medical diagnoses perished under changing medical paradigms, intermittent fever 'survived' into the twentieth century. This article studies the development in how intermittent fever was framed in Denmark between 1826 and 1886 through terminology, clinical symptoms and aetiology. In the 1820s and 1830s, intermittent fever was a broad disease category, which the diagnosis 'koldfeber'. Danish physicians were inspired by Hippocratic teachings in the early nineteenth century, and patients were seen as having unique constitutions. For that reason, intermittent fevers presented itself as both benign and severe with a broad spectrum of clinical symptoms. As the Parisian school gradually replaced humoral pathology in the mid-nineteenth century, intermittent fever and koldfeber became synonymous for one disease condition with a nosography that resembles modern malaria. The nosography of intermittent fever remained consistent throughout the second half of the nineteenth century. Although intermittent fever was conceptualized as caused by miasmas throughout most of the nineteenth century, the discovery of the Plasmodium parasite in 1880 led to a change in the conceptualization of what miasmas were. The article concludes that the development of how intermittent fever was framed follows the changing scientific paradigms that shaped Danish medicine in the nineteenth century.