Quinine London. It remained the antimalarial drug of choice until the 1940s, when other drugs took over. The form of quinine most effective in treating malaria was found by Charles Marie de La Condamine in 1737. In 1820, French researchers Pierre Joseph Pelletier and Joseph Bienaimé Caventou first isolated quinine from the bark of a tree in the genus "Cinchona" - probably "Cinchona officinalis" - and subsequently named the substance. The name was derived from the original Quechua (Inca) word for the cinchona tree bark, "quina" or "quina-quina", which means "bark of bark" or "holy bark". Prior to 1820, the bark
Tree converted into bark and the cambium layer creates new phloem and xylem cells. The bark is inelastic. Eventually the growth of a tree slows down and stops and it gets no taller. If damage occurs the tree may in time become hollow. Leaves are structures specialised for photosynthesis and are arranged on the tree in such a way as to maximise their exposure to light without shading each other. They are an important investment by the tree and may be thorny or contain phytoliths, lignins, tannins or poisons to discourage herbivory. Trees have evolved leaves in a wide range of