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.
Hippocrates to Galen, a later physician, Polybus was Hippocrates' true successor, while Thessalus and Draco each had a son named Hippocrates (Hippocrates III and IV). Soranus said that Hippocrates learned medicine from his father and grandfather (Hippocrates I), and studied other subjects with Democritus and Gorgias. Hippocrates was probably trained at the asklepieion of Kos, and took lessons from the Thracian physician Herodicus of Selymbria. Plato mentions Hippocrates in two of his dialogues: in "Protagoras", Plato describes Hippocrates as "Hippocrates of Kos, the Asclepiad"; while in "Phaedrus", Plato suggests that "Hippocrates the Asclepiad" thought that a complete knowledge of the nature