Unpublished paper, 'Remarks, on an acrid principle pervading several genera of plants' by John Frost Frost writes on experiments that seek to prove that an acrid purgative principle exists in several genera of plants, including Jatropha, Ricinus, Euphorbia, and Croton. He names the principle 'Jatrophine'. John Frederick William Herschel has written his initials next to the date received. A graphite inscription final page verso reads 'Not to be', which is struck out, and below, 'Archives'. Numerous deletions appear throughout in graphite. Subject: Botany / Chemistry Written by Frost at 29 Bridge St, Blackfriars [London]. Communicated by Sir James McGrigor. Received by the Royal Society on Wednesday 30 May 1827. Read 21 June 1827. May 1827