The saturated paraffin hydrocarbon, n-hep-tacosane (C27H56), is found in coal tar, beeswax, flowers, tobacco and roasted coffee. There was available to the authors the alcohol soluble extract obtained after precipitating 18 1. of human sperm fluid with a methyl-ethyl alcohol mixture. This alcoholic soln. was concd. to 750 ml. on the water bath in vacuo and placed in the ice box. The crystals which formed were separated by centrifugalization and extracted with 1.5 1. acetone. The residue remaining was extracted with 2 1. alcohol-ether (1:1), the extract concd. to 250 ml., placed in the ice box and 0.5 g. of the crystals which formed refluxed with 20 ml. benzene, 25 ml. alcohol and 1.5 g. KOH for 4 days. The mixture was concd. in vacuo, and crystals of n-heptacosane, m. 58[degree]-60[degree], isolated from the ether soluble neutral fraction. The yield was 1 g. of heptacosane from the alcoholic extract, but since hep-tacosane is difficultly soluble in alcohol, only a fraction of the amt. present in the sperm fluid was recovered. Other substances isolated from the alcoholic extract were palmitic and stearic acids, spermine, and tyrosine.