History of aspirin tree in 1758 and noticed an astringency reminiscent of the standard—and expensive—ague cure of Peruvian bark. He collected, dried, and powdered a substantial amount of willow bark, and over the next five years tested it on a number of people sick with fever and agues. In his letter, Stone reported consistent success, describing willow extract's effects as identical to Peruvian bark, though a little less potent. (In fact, the active ingredient of Peruvian bark was quinine, which attacked the infectious cause of malaria, while the active ingredient of willow extract, salicin, relieved the symptoms of malaria but could not cure
Tree pine ("Pinus" species) the bark exudes sticky resin which deters attackers whereas in rubber trees ("Hevea brasiliensis") it is a milky latex that oozes out. The quinine bark tree ("Cinchona officinalis") contains bitter substances to make the bark unpalatable. Large tree-like plants with lignified trunks in the Pteridophyta, Arecales, Cycadophyta and Poales such as the tree ferns, palms, cycads and bamboos have different structures and outer coverings. Although the bark functions as a protective barrier, it is itself attacked by boring insects such as beetles. These lay their eggs in crevices and the larvae chew their way through the cellulose