Heve'a (brasilien'sis and H. Guianen'sis), Elastica, Rubber. -- The prepared milk-juice, U.S.P. 1890-1900; S. America, east of Andes, India, near streams. Large trees, smooth straight trunks, 15-18 M. (50-60 degrees) high; leaves trifoliate, leaflets obovate, 10 Cm. (4') long, dark green; flowers racemes. Resin (rubber), in flask-shaped, roundish masses, incised pieces showing laminated structure, lighter than water, brownish-black, internally lighter, mottled, tough, elastic, odor creosote-like, almost tasteless; solvents: chloroform, carbon disulphide, oil of turpentine, petroleum benzin, benzene; melts at 125 degrees C. (257 degrees F.), soft and adhesive on cooling; heated with sulphur 10 p.c. -- vulcanized and insoluble; with 40 p.c. -- hard rubber (ebonite). Milk (resembling cow's) exudes from small pick holes, being caught in small cups, emptied into large vessels and conveyed to smoking station, where wooden paddles (lower end) are dipped repeatedly into it (then sometimes into sand -- adulteration), and rotated in a column of smoke until coagulated and mass has attained considerable size; contains resin (caoutchouc) 32 p.c., volatile oil, fixed oil. Base of plasters; woven into fabrics to compress and support relaxed muscles and parts; hard rubber in surgical implements--bougies, catheters, pessaries, specula, syringes, etc.