It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree. Some of the more common ingredients are cascarilla, cassia, gentian, orange peel, and cinchona bark. Aperol is made of gentian, rhubarb, and cinchona, among other ingredients. Sappington began importing cinchona bark from Peru in 1820. The indigenous peoples of Peru made a tincture of cinchona to control fever. Additionally, they began harvesting wild cinchona bark during the Cinchona Missions. The birth of homeopathy was based on cinchona bark testing. The bark of cinchona can be harvested in a number of ways. The history of cinchona bark dates back more than 350 years. The curative properties of cinchona were known much earlier. Spanish Jesuit missionaries were the first to bring cinchona to Europe. In the nineteenth century, Franz Junghuhn introduced the cinchona ("kina") plant. Humboldt later published a treatise in English on cinchona. The bark is cheaper than bark of "Cinchona".