A Remarkable Case of Geometrical Isomerism

Abstract

AN exceptionally interesting memoir is contributed to the current number of Liebig's Annalen by Prof. Wislicenus of Leipzig, who has latterly identified himself so earnestly with the subject of molecular configuration. It has been suspected for some years that there are two isomeric unsaturated acids of the composition C₄H₇.COOH. One of these substances exists in the free state in the roots of Angelica archangelica and has therefore received the name of angelic acid. The other compound is found along with angelic acid in Roman oil of cumin and has been termed tiglic acid. These two acids, moreover, behave so similarly in almost all their reactions with other substances that the conclusion has been rendered inevitable that they must be represented not only by the above formula, but by the same constitutional formula,