METABOLISM OF INDENE 269 c8-and tran8-diol, together with indan-2-one (Loon, 1919). So far, however, there is no experimental evidence to show that epoxide formation occurs in the aniimal body during the metabolism of indene. SUMMARY 1. Indene has been administered to rabbits by stomach tube, and fractionation of ether extracts of the urine has yielded optically active c8and tran8-indane-1:2-diol in a total amount corresponding to about 5 % of the dose. Acid treatment of the urine, either before or after ether extraction, yielded indan-2-one in amounts corresponding to about 25 % of the dose of indene. 2. The same two diols have been isolated from the urine of rabbits dosed with indene by subcutaneous injection. 3. c8-Indane-1:2-diol has been isolated from ether extracts of the urine of rats dosed with indene by stomach tube. Indan-2-one has been obtained by acid treatment of the extracted urine. 4. The interconversion of cisand tran8-indane-1:2-diol has been studied, and the metabolic formation of the two diols is discussed. The authors gratefully acknowledge the support this work has received from the Endowment Fund of St Thomas's Hospital. The elementary microanalyses were carried out by Weiler and Strauss, Oxford.