Aethusa. Fool's Parsley. Aethusa Cynapium, L. (Fam. Umbelliferae.)—A fetid herb naturalized from Europe and growing in waste places or cultivated grounds in the northern United States and Canada. In 1859, Walz stated that the fruit of the Aethusa Cynapium contains a volatile base similar to coniine. This statement has been confirmed by Power and Tutin (J. Am. C. S., 1905, xxvii) who recovered, besides various inert matters, about one forty-thousandth of 1 per cent. of the volatile alkaloid. This plant has been variously attributed with poisonous properties, but Harley (P. J., 1880, xi, p. 43) denies any noxious quality, and, in the experiments of Power and Tutin, the extract from five hundred grammes of the dry herb caused in a small dog, vomiting and salivation, but the animal entirely recovered.