Before the nineteenth century, European soldiers serving in the tropics died from disease at a rate several times higher than that of soldiers serving at home. Then, from about 1815 to 1914, the death rates of European soliders, both those serving at home and abroad, dropped by nearly 90%. But this drop applied mainly to soliders in barracks. Soldiers on campaign, especially in the tropics, continued to die from disease at rates as high as ever, in...