208 THE AFRICAN RUBBER VINES 



of the training of the rubber collectors, and the vines 

 are now much more carefully looked after and tapped 

 than formerly. From the evidence available, it seems 

 probable that certain species of rubber vines, e.g. Lan- 

 dolphia Heudelotii and Landolphia owariensis, could be 

 tapped repeatedly without permanent injury if the 

 above-mentioned precautions were rigorously observed, 

 but it is almost impossible to ensure this in the forests. 

 Experiments made on L. owariensis vines in the Bahr- 

 el-Ghazal Province of the Sudan showed that narrow 

 incisions made with a triangular tapping-knife yielded 

 as much rubber as the larger cuts employed by the natives, 

 and that such incisions healed completely within five 

 months. 



It is contended, however, by some authorities that 

 tapping is an entirely Avrong method of exploiting rubber 

 vines, as, in their opinion, no matter how carefully the 

 tapping is done, the vines will inevitably be kiUed by 

 the treatment. They maintain that the alternative 

 native plan of cutting down the vines, draining the latex 

 from the cut stems, and finally extracting the rubber 

 from the dried bark, is far preferable to any tapping 

 process. The advantages claimed for this procedure 

 are that it gives a larger yield of rubber than can be 

 obtained by tapping, and that the vines are not killed, 

 but put out new shoots from the basal portion of the stem. 

 It is stated that these shoots can be treated in the same 

 manner in two or three years' time, as the rubber they 

 yield is much superior in quality to that furnished by 

 seedling vines of the same age. In using this method, 

 care should be taken to cut the vines at least 30 in. 

 above the ground so as to leave a good " stool " for the 

 development of new shoots. 



It is not possible at present to express a definite 

 opinion as to the effect of cutting down the vines on a 

 large scale, but the method has come into considerable 

 favour recently, and has been adopted in the Belgian Congo 

 instead of the tapping process. It is no doubt true that 

 the native methods of tapping usually destroy the vines, 

 and probably certain species of vines, even if carefully 

 tapped, are very liable to be killed by the treatment, 

 as in the case of M. Seret's experiments on the tapping 

 of Clitandra Arnoldiana (see p. 203). It must, however. 



