Facts and hypothesis in French nineteenth-century physiologyThe historiographical studies focused on French nineteenth-century physiology have eventually enshrined the thesis that the need to resort to hypotheses was assumed and proclaimed for the first time within the works and scientific practice of Claude Bernard (1813-1888). His teacher, François Magendie (1783-1855), is presented as a figure that fights against vitalism and that, devoted to an absolute empiricism, only admits the bare facts as constitutive elements of science. He accepted generalizations—as long as they were not premature— from what he called materials collected within experience, but rejected that ideas or hypotheses could lead the scientific path. Although this image of Magendie is widely shared —and was even prompted by some of his statements— this paper aims to show precisely that it is an image that does not correspond to reality. Magendie did know the crucial role of hypotheses within physiological research. Not only that; he used them extensively in his scientific work and in his activity as a researcher committed to the implementation of experimental physiology