On the comparative toxicity of theobromine of thebromine and caffeine, as measured by their direct effect upon the contractility of isolated muscle

The isolation of caffeine from coffee is generally assigned to Robiquet, Pelletier and Caventou (1821), though the so-called coffee base, obtained a year previously by Runge was probably impure cafferine. The identify of theine, extracted from tea by Oudey (1838), with caffeine was established by the analyses of Jobst (1843). The association of caffeine with uric acid was noted originally by Stenhouse, who found the latter in a sample of Paraguay tea.