296 



The World's Commercial Products 



By permission of Messrs. Maclaren &■■ Co., i>)we Lane 



FICUS ELASTICA, SHOWING TANGLED GROWTH 



Kirkii, which ranges from 

 German East Africa to Natal. 

 Recently Mr. M. T. Dawe has 

 added an important new species, 

 which he found in Uganda, 

 and has been named L. Dawei 

 after him. It yields very good 

 rubber. Interestingly enough, 

 it also occurs in the Came- 

 roons, on the west coast. In 

 Madagascar there are several 

 species, of which L. Mada- 

 gascariensis, L. Perrieri, and 

 L. sphaerocarpa are the most 

 important. 



Collection. The natives 

 make incisions in the stems of 

 these plants, and catch and 

 coagulate the latex in various 

 ways. Sometimes it is allowed 

 to run into receptacles, and 

 either coagulates by itself, or is 

 induced to do so by addition 

 of a little lime juice, or other 

 plant juices, or by heating. At 

 other times the native smears 

 the milky juice over his body, 

 peeling it off when it has formed 

 a film. Some also hardens on 

 the plant and is pulled away. 

 The mode in which the various 

 Landolphia rubbers come on 

 the market varies considerably. 

 If coagulated in bulk, it may 

 be cut up into strips which are 

 rolled up to form " twists " or 

 " balls," or it may be exported 

 in " lumps," in small pieces 

 known as " thimbles," or in 

 various other forms which we 

 have not space to enumerate. 



GUAYULE RUBBER 



This rubber, which has recently come into notice, is obtained from a plant known as 

 Parthenium argentatum, fairly closely related to the Sunflower of the Compositae, and is of inter- 

 est as being the only plant in this large order known to produce rubber. Whereas the rubber 

 plants already described are mainly trees or large woody climbers, this is a small herba- 

 ceous plant varying, in height from a few inches to between three and four feet. It occurs 

 principally in North Mexico on the "bush prairies," but extends also into the southern 

 United States. 



The rubber contained in this plant cannot be obtained by tapping, as in ordinary rubber 



