History of aspirin other studies from the 1960s to the 1980s established aspirin's efficacy as an anti-clotting agent that reduces the risk of clotting diseases. Aspirin sales revived considerably in the last decades of the twentieth century, and remain strong in the twenty-first with widespread use as a preventive treatment for heart attacks and strokes. Medicines derived from willow trees and other salicylate-rich plants have been part of pharmacopoeias at least dating back to ancient Sumer. The Ebers Papyrus, an Egyptian medical text from ca. 1543 BCE, mentions use of willow and myrtle (another salicylate-rich plant) to treat fever and pain. Willow bark
Bark pocket Bark pocket Bark pockets can be formed by inosculation, formation of a tree fork, encapsulation of a branch, joining together of an uneven trunk, or encapsulation of another object. During inosculation, the bark trapped between the two joining trunk becomes surrounded with wood once the trunks fuse. The resulting bark pocket formed during inosculation or in a tree fork is referred to as included bark. When a branch is encapsulated, the outer bark on the branch may remain inside the wood of the tree, as the trunk widens and grows around the branch. Bark pockets can be used as an