AbstractBy extracting separately hair from boys, girls, men, and women with organic solvents, different samples of grease were obtained. Among these, the constituents of man hair grease were thoroughly investigated. 6.7‐Hexadecenoic acid was found to be the characteristic constituent. The presence of jimmoarachidic acid C20H40O2, m.p.70°C**, myristic,. palmitic, stearic, oleic and ricinoleic acids were also comfirmed. The unsaponifiable matter was found to consist of cholesterol and other sterols, as well as other neutral substan es. Woman hair grease was examined less thoroughly. The presence of myristic, palmitic, stearic, 6,7‐hexadecenoic, oleic acids only were proved. The lower acids, which were present in the form of esters, were found to exhibit high optical acti