^10 THE AFRICAN RUBBER VINES 



require a considerable amount of protection in the young 

 state, which is difficult to give when they are scattered 

 through the forest. Better results were obtained by 

 sowing the seed m baskets made of some fibrous material, 

 and, when the vines were a year old, planting them out 

 without removing the basket, so as to avoid disturbing 

 the roots. 



It has been pointed out aheady that the stems of 

 vines growing in dense forest only mcrease in thickness 

 very slowly, and in consequence of this fact more open 

 situations were latterly chosen for planting purposes, 

 in order that the young vines might be exposed to light 

 and air. A further modification, vrhich is probably 

 the best arrangement, is to plant the young vines in the 

 open at the same time as quick- growing trees, such as 

 species of Albizzia, vv^hich are to serve as supports for 

 the plants. In this way the vines and trees grow up 

 together and the maximum development of the vines 

 is obtained. 



Full information on the subject of the cultivation of 

 rubber vines will be found in the Manuel fratique de la 

 culture et de V exploitation des essences caoutchoutiferes 

 indigenes et introduites au Congo Beige* 



Composition of Vine Rubbers. — The rubber obtained 

 from many of the vmes is of excellent quality if carefully 

 prepared, and specuuens in the form of biscuits or sheet 

 frequently contam over 90 per cent, of caoutchouc and 

 low jjcrcentages of resin, protein, and ash. The amount 

 of resin usually ranges from 4 to 10 per cent, according 

 to the species, and in Landolphia rubbers the percentage 

 of protem is almost always less than 2 per cent, and 

 frequently less than 1 per cent. Specially prepared 

 Landolphia rubber contains less protein than any other 

 variety of rubber. 



The ball rubber as collected by natives, and also the 

 " root rubbers," always contain more or less vegetable 

 impurity in the form of fragments of bark, but in the 

 best qualities this is reduced to a minimum. 



The " paste " or '' flake "' rubbers prepared from 

 certain vines are of very resinous natuie and consequently 

 of low value. 



• Brussels: Imprimeric A. Lesigne, 27, rue do la Charity, 1909. 



