WISLICENUS, JOHANNES (1835-1902), German chem ist, was born on June 24, 1835 at Klein-Eichstedt, in Thuringia, and emigrated to America with his father. In 1855 he was appointed lecturer at the Mechanics' Institute in New York. Returning to Europe in 1856, he continued his studies at Ziirich university, where he was subsequently professor of chemistry from 1865 to 1872. He then obtained the chair of chemistry at Wiirzburg, and in 1885, on the death of A. W. H. Kolbe, was appointed to the same professorship at Leipzig, where he died on Dec. 6, 1902. His work on the lactic acids cleared up many difficulties concerning the combination of acid and alcoholic properties in hydroxy-acids in general, and resulted in the dis covery of two substances differing in physical properties though possessing a structure of proved chemical identity. So far back as 1873, before the publication of the doctrine of J. H. van't
Hoff and J. A. Le Bel, Wislicenus expressed the opinion that the ordinary constitutional formulae did not afford an adequate explanation of certain carbon compounds, and suggested that account must be taken of the verschiedene Lagerung ihrer Atome ins Raume. Later (see Die rliumliche Anordnung der Atome in organischen Molekiden, 1887) he extended the application of the van't Hoff-Le Bel theory to "geometrical isomers"—substances like fumaric and malefic acids which have identical formulae but are dissimilar chemically. Wislicenus and his pupils studied a number of cases of this type of isomerism. He is also known for his work on aceto-acetic ester and its application as a syn thetical agent and for his syntheses in the penta-methylene series. He was awarded the Davy medal by the Royal Society in 1898.