282 



INDUSTRIAL PLANTS 



of crude rubber for various articles including water-vessels, 

 shoes, and torches. Similai- prehistoric use was made bj^ the 

 East Indians of the product they obtained from the india- 

 rubber tree (Fig. 271) which yet remains one of the more 

 important Asiatic sources of this remarkable substance. 



Simple, primitive methods of obtaining the raw material 

 are still practised very generally by the natives of to-day who 

 in various parts of the world collect the rubber which is ex- 



FiG. 271. — India Rubber-tree (Ficuti clasticn, Mulberry Family, Moracece). 

 Tip of branch showing leaves, the 5'oungest unfolding and still partly 

 enwrapped by the protective stipule-case. (Original.) — ^Trec growing 

 30 m. tall; leaves thick and glossy; flowers similar to those of the fig 

 (see page 102); fruit fig-like, greenish-yellow. Native home. Tropical 

 Asia. 



ported to Europe and America for manufacture. First, ax 

 cuts are made in the bark of a good-sized tree in such a 

 wa}^ that the milk whicl; flows from the wounds will run into 

 little cups so placed as to receive it. The collector on his 

 rounds empties the contents of these into a larger vessel 

 which he finally carries to where the milk is to be curdled. 

 The separation of the caoutchouc from the whey-like part 

 of the milk is accomplished variously; as for example, by 

 mere exposure to th(^ air, or by the addition of water or vari- 

 ous salts; but the best rubber is obtained by the process of 

 smoking as practised in Brazil. Over a smoky fire, made by 

 burning Brazil-nut shells or certain palm seeds, the operator 

 holds the broad end of a clay-covered paddle which has been 

 dipped in the fresh milk, and turns it slowly till an even layer 



