Caoutchouc (resin)

The pure, milky, sticky, elastic, resinous juice obtained from various species of the tropical genera Hevea and Ficus. It coagulates on exposure to the air, becomes highly elastic, and is waterproof. Distinguished from "gutta-percha" in that caoutchouc must be heated longer to set. In the early 19th century, the name "caoutchouc" was also used for a commercial rubber-based cement in which a small amount of the elastomer was dissolved in a solvent and mixed with mastic. Today, this material is called "latex."