"Beware Against the poison that is Africa, there is but one antidote: Vichy." So ran a 1924 advertisement for one of France's main spas. Throughout the French empire, spas featuring water cures, often combined with "climatic" cures, thrived during the nineteenth century and the twentieth. Water cures and high-altitude resorts were widely believed to serve vital therapeutic and even prophylactic functions against tropical disease and the tropics themselves...