Malaria saved the lives of thousands of workers and helped develop the methods used in future public-health campaigns against the disease. The first effective treatment for malaria came from the bark of cinchona tree, which contains quinine. This tree grows on the slopes of the Andes, mainly in Peru. The indigenous peoples of Peru made a tincture of cinchona to control fever. Its effectiveness against malaria was found and the Jesuits introduced the treatment to Europe around 1640; by 1677, it was included in the London Pharmacopoeia as an antimalarial treatment. It was not until 1820 that the active ingredient, quinine,
Bark bread known from the 1890s, and in Finland "pettuleipä" (literally "pinewood-bark bread") was produced as ersatz bread during the Finnish Civil War of 1918. Finger sized twigs and branches were collected from deciduous trees and shrubs, and the bark split and the inner bark (the phloem and sometimes the vascular cambium) collected while still fresh. The yellow or green inner bark (depending on tree species) was dried over open fire, in an oven or dried in the sun for a few days. A mortar or mill was used to grind the bark to a fine powder to add to the flour.