The Nuttall Encyclopedia
Seed of an African bean, employed in medicine, known as the Ordeal Bean, as, being poisonous, having been used to test the innocence of people charged with witchcraft.
Wood, James, ed. Entry for 'Calabar Bean'. The Nuttall Encyclopedia. https://www.studylight.org/encyclopedias/eng/nut/c/calabar-bean.html. Frederick Warne & Co Ltd. London. 1900.