ABSTRACT
I. INTRODUCTION Natural rubbers have been used for a long time. As early as 500 B.C., there were indications that the Indians in Mexico played with rubber balls. Spanish explorers in the 15th and 16th centuries wrote of bouncing balls and waterproof shoes from Brazil and Mexico. Today, at least well over 400 different shrubs, vines, and trees have been identified that produce natural rubber latex. Hevea brasilliensis (natural rubber trees) are cultivated in Central America, Mexico, Southeast Asia, Africa, and South America.
