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 hack Bark hack A bark hack is a tool used to remove pine tree bark to promote the flow of pine resin, which is used in naval stores production. The tool consists of a wooden shaft with a weighted butt and hook-like, replaceable, U-shaped blades at the head. The bark hack is swung much like an axe and is used to create a hatched chevron pattern ("cat face" or less frequently, a "blaze") into trees' exposed sapwood. The weighted end helps the operator follow through with the force necessary for the hooked blade to scoop out chips of hard pine wood.