Dehydration of cholesterol with zinc dust and subsequent fractionation of the oily product resulted in 6 fractions from which the following crystalline substances were obtained: naphthalcne, a substance of molecular weight 219, and chry-sene. Dehydration of cholic acid by the same technique and study of the products resulted in isolation of an unidentified crystalline mass melting between 191 and 194[degree] and evidently a mixture, a substance similar to but not identical with chrysene, another unknown crystalline material melting at 194-196[degree], and a crystalline mass melting at 277[degree] but not identified.