Esterified Cholesterol in Surface Lipids: Methods of Isolation and Fatty Acid Content**From the Department of Dermatology, Stanford University School of Medicine, Palo Alto, California 94305.

The chromatographic separation of cholesteryl esters and wax esters has been reexamined. A convenient and satisfactory procedure involves partial removal of wax esters with urea, followed by TLC of the residual material on alumina. Examination of the double bond isomers present in the monounsaturated fatty acids in the cholesteryl ester fraction supports an earlier conclusion that most of the cholesteryl esters are of sebaceous origin