Edward Stone (natural philosopher) piece of bark from a willow tree and was struck by its extremely bitter taste. Knowing that the bark of the Peruvian cinchona tree − from which quinine (used in the treatment of malarial fevers) is derived − has a similarly bitter taste, he surmised that the willow might also have therapeutic properties. Stone's interest in willows was due to the ancient "doctrine of signatures" – whereby the cause of a disease offers a clue to its treatment. According to Stone: "As this tree delights in a moist or wet soil, where agues chiefly abound, the general maxim that many
Bark painting from Stringybark ("Eucalyptus tetradonta"). The bark must be free of knots and other blemishes. It is best cut from the tree in the wet season when the sap is rising. Two horizontal slices and a single vertical slice are made into the tree, and the bark is carefully peeled off with the aid of a sharpened tool. Only the inner smooth bark is kept and placed in a fire. After heating in the fire, the bark is flattened under foot and weighted with stones or logs to dry flat. Once dry, it is ready to paint upon. Earth pigments—or ochres—in