Stone, a vicar from Chipping Norton, Oxfordshire, discovered that the bark of the willow tree (active ingredient: salicylic acid) was effective in reducing a fever. This was the first report in the scientific literature of a traditional remedy known since antiquity, and an ethnobotanical remedy widely used by native Americans, and perhaps other native peoples. Remarkably the remedy seems to have been forgotten or unknown to the scientific establishment until Stone published. Digital facsimile from the Royal Society at this link.