This article takes as its starting point the commonplace that Rousseau's "Emile" enabled his contemporaries to discover not only childhood but physical education. Focused on what the pedestal erected for Jean-Jacques somewhat overshadows, a brief historiographic overview and a survey of some major writings on education before Rousseau (by the Abbot Fleury, John Locke, Jean-Pierre de Crousaz and Charles Rollin) will show that the ideas defended by the writer were not innovative in the slightest. But also, and this seems far more important, that these ideas took place in a particular context : the mid-eighteenth century dispute between pedagogues and physicians over the body of the child, which resulted as much from the medicalization of pedagogy as from the educationalization of medicine, at a time when the boundaries between disciplines had not yet been defined. In the context of the ascension to power of physicians, reinforced by the first statistics on child mortality, as will be suggested in conclusion, Rousseau's advocacy for corporal education gave the initiative back to the pedagogues.