64 TAPPING SYSTEMS 



given, reserving a more detailed account until dealing 

 with the particular plants to which they are specially 

 applicable. 



Rubber is usually prepared by tapping the stems of 

 the living plants and subsequently coagulating the latex 

 thus obtained. In certain cases, however, the natives of 

 parts of Africa and America frequently feU the trees or 

 cut down the vines in order to obtain the rubber. This 

 plan is employed in preparing the rubber of Funtumia 

 elastica in parts of West Africa, and very commonly 

 throughout Central Africa for obtaining the rubber from 

 Landolphia and other vines ; it is also generally adopted 

 by the natives in the Amazon valley for preparing the 

 rubber of Castilloa Ulei. After felling the trees, the natives 

 either extract the latex by making numerous circular 

 incisions extendmg right round the trunk, or they allow 

 the bark to dry, then strip it from the stem and prepare 

 the rubber from it by a process of beating. The stems of 

 the vines are usually cut into short lengths and the latex 

 allowed to drain out, a further quantity of rubber bemg 

 obtained in some cases by beating the dried bark. This 

 method of felling the trees is very destructive and speedily 

 leads to their extermination. 



Turning to the tapping processes, there are a large 

 number of different methods of making the incisions. 

 In some cases, as already mentioned, incisions are made 

 in the bark by means of a sharp instrument, and no bark 

 is cut out (the method of " incision ") ; whilst in other 

 processes portions of the bark are removed in forming 

 the cuts (the method of " excision "), Examples of native 

 incision methods are seen in the tapping of Hevea brasi- 

 liensis by means of a small axe with a very short cutting 

 edge, and of Castilloa elastica by means of a machete. 

 Native excision methods, on the other hand, are illustrated 

 by the tapping of Funtumia elastica by means of a native 

 gouge, and by the removal of large slices of bark from 

 Landolphia vines. 



As the laticiferous vessels run longitudinally in the 

 cortex, it is evident that a transverse (horizontal) incision 

 will open many more vessels than a longitudinal (vertical) 

 cut. A horizontal incision is, however, not well adapted 

 for the collection of the latex, as it does not form a channel 

 along which the latex can flow. The result of using 



