HISTORY AND GENERAL CONDITIONS 3 



It is from the various species of the Hevea that the 

 greater part of the rubber of the Amazon Valley is 

 obtained. Of these, some seventeen varieties are 

 known to exist, the most common being the Hevea 

 Brasiliensis, the Hevea Guayanensis, and the Hevea 

 spruceana. The Castilloa elastica, yielding the product 

 known locally as caucho, as distinct from goma, or 

 rubber, is found principally on the higher reaches of 

 the Amazon tributaries, and of recent years has pro- 

 vided one-fifth of the total rubber exports from Brazil. 



The mainstay of the Amazon Valley industry is the 

 Hevea Brasiliensis, the three varieties most in evidence 

 being the black (preta), the white (branca), and the red 

 (vermelho). Broadly speaking, it may be said that the 

 white and red species belong more particularly to the 

 districts of the Lower Amazon and its feeders ; the 

 black to the upper rivers and the territories adjoining 

 the frontier of Bolivia, and also in certain sections of 

 that country. In this latter area are found also trees 

 of the white and red variety, the former in greater 

 abundance than the latter. 



It is from the latex of the black Hevea that the 

 finest rubber is prepared, and when free from impuri- 

 ties, and without any addition of latex from other 

 varieties, it is undoubtedly of exceptional value on 

 account of its high standard of resiliency. The best 

 quality of this rubber is classified as "fine hard Para," 

 the lower grade being placed on the market as entre 

 fina. The tree grows to a great size in girth and 

 height, and yields freely, the latex being of high 

 density, and easily, although slowly, coagulated by the 

 smoke of the Urucury nuts employed for this purpose. 



