Caoutchouc

(kōo'chōok), n. [Fr. caoutchouc, caoutchouc, a South American word.] A vegetable substance obtained from incisions made in several plants, affording a milky juice, as the Urceola elastica, a tree of tropical Asia, the Ficus elastica, a species of fig in Nepaul, and especially the Siphonia elastica (Hevea elastica of some botanists), a euphorbiaceous plant of South America. It is white at first, and assumes the dark shade usually possessed on exposure to smoke. It is impermeable to water, tenacious, elastic, unalterable by exposure to air, fusible at 150°, soluble in ether and the essential oils. It is also called India rubber (having been first used to erase pencil marks) and gum elastic.

Vulcanized caoutchouc, caoutchouc compounded with a small proportion of sulphur, by which it is rendered hard and elastic like horn;—so called because subjected to a high degree of heat during the process of manufacture. It is used for a great variety of purposes in the arts.