lactucic acid

Century Dictionary and Cyclopedia

1. n. A bitter, acrid, brownish-green, amorphous compound obtained from the juice of Lactuca Canadensis.
2. n. A light-yellow crystalline compound, C₄₀H₅₈O₁₁(?), formed by the action of dilute sulphuric acid on lactcuarium. It gives a wine-red color with alkalis.

Wiktionary

1. n. chemistry Any of various acids derived from the juice of Lactuca virosa.