a modern myth that Hippocrates used willow as a painkiller. Hippocrates, Galen, Pliny the Elder, and others knew that decoctions containing salicylate could ease pain and reduce fevers. It was used in Europe and China to treat these conditions. This remedy is mentioned in texts from Ancient Egypt, Sumer, and Assyria. The Cherokee and other Native Americans use an infusion of the bark for fever and other medicinal purposes. In 2014, archaeologists identified traces of salicylic acid on seventh-century pottery fragments found in east-central Colorado. The Reverend Edward Stone, a vicar from Chipping Norton, Oxfordshire, England, reported in 1763 that the bark of the willow was effective in reducing a fever. An extract of willow bark, called salicin, after the Latin name for the white willow (Salix alba), was isolated and named by German chemist Johann Andreas Buchner in 1828. A larger amount of the substance was isolated in 1829 by Henri Leroux, a French pharmacist. Raffaele Piria, an Italian chemist, was able to convert the substance into a sugar and a second component, which on oxidation becomes salicylic acid. Salicylic acid was also isolated from the herb meadowsweet (Filipendula ulmaria, formerly classified as Spiraea ulmaria) by German researchers in 1839.<ref>{{cite journal|first1=C. |last1=Löwig |first2=S. |last2=Weidmann |journal=Annalen der Physik und Chemie; Beiträge zur Organischen Chemie (Contributions to Organic Chemistry)|url=|year=1839|issue=46 |pages= 57–83|title=III. Untersuchungen mit dem destillierten Wasser der Blüthen von Spiraea Ulmaria | trans-title=III. Investigations of the water distilled from the blossoms of Spiraea ulmaria}} Löwig and Weidman called salicylic acid Spiräasaure (spiraea acid)</ref> Their extract caused digestive problems such as gastric irritation, bleeding, diarrhea, and even death when consumed in high doses. In 1874 the Scottish physician Thomas MacLagan experimented with salicin as a treatment for acute rheumatism, with considerable success, as he reported in The Lancet in 1876. Meanwhile, German scientists tried sodium salicylate with less success and more severe side effects. In 1979, salicylates were found to be involved in induced defenses of tobacco against tobacco mosaic virus. In 1987, salicylic acid was identified as the long-sought signal that causes thermogenic plants, such as the voodoo lily, Sauromatum guttatum, to produce heat. Dietary sources Salicylic acid occurs in plants as free salicylic acid and its carboxylated esters and phenolic glycosides. Several studies suggest that humans metabolize salicylic acid in measurable quantities from these plants. High-salicylate beverages and foods include beer, coffee, tea, numerous fruits and vegetables, sweet potato, nuts,