Tolu, Balsam of

a thick aromatic liquid exuded from incisions in the bark of the South American tree Myraxylon (Toluifera) balsamum (family Papilionaceae). Upon exposure to air it hardens into a reddish brown mass. It contains benzoic and cinnamic acids, both in the free state (12–15 percent) and as esters (up to 86 percent). It also contains insignificant amounts of essential oils and vanillin. Its density is 1.2 g/cm³, and its melting point is –60°–65°C. It is soluble in alcohol, acetic acid, acetone, chloroform, and solutions of potassium hydroxide. Balsam of Tolu is used in the manufacture of perfumes.