Bark (botany) rope, used for example in the rigging of Viking age longships. Among the commercial products made from bark are cork, cinnamon, quinine (from the bark of Cinchona) and aspirin (from the bark of willow trees). The bark of some trees notably oak ("Quercus robur") is a source of tannic acid, which is used in tanning. Bark chips generated as a by-product of lumber production are often used in bark mulch in western North America. Bark is important to the horticultural industry since in shredded form it is used for plants that do not thrive in ordinary soil, such as epiphytes.
History of aspirin attacks were more deadly. Jick had found that fewer aspirin-takers were admitted to his hospital for heart attacks than non-aspirin-takers, and one possible explanation was that aspirin caused heart attack sufferers to die before reaching the hospital; Elwood's initial results ruled out that explanation. When the Elwood trial ended in 1973, it showed a modest but not statistically significant reduction in heart attacks among the group taking aspirin. Several subsequent studies put aspirin's effectiveness as a heart drug on firmer ground, but the evidence was not incontrovertible. However, in the mid-1980s, with the relatively new technique of meta-analysis, statistician Richard