lactucerin

from The Century Dictionary.

• noun The dried milky juice of the European lettuce, Lactuca virosa. It consists of a mixture of α- and β-lactucerol acetates and has the formula C₂₀H₃₂O₂.
• noun A colorless dextrorotatory compound, C₂₈H₄₄O₂ (?), contained in the juice of the European lettuce. It crystallizes in microscopic needles and melts at 210° C. Also called lactucon.