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
Cinchona people. Italian sources spelt Quina as Cina which was a source of confusion with "Smilax" from China. Haggis argued that Qina and Jesuit's bark actually referred to "Myroxylon peruiferum" or Peruvian balsam and that this was an item of importance in Spanish trade in the 1500s. Over time, the bark of the "Myroxylon" was adulterated with the similar looking bark of what we now know as "Cinchona". Gradually the adulterant became the main product that was the key therapeutic ingredient used in malarial therapy. The bark was included as "Cortex Peruanus" in the London Pharmacopoeia in 1677. The "fever tree"