February, 1910.] 



103 



Saps and Exudations. 



been laid out without proper shade 

 trees, and as mixed plantations of Hevea 

 with cacao. Also the Liberia coffee 

 plantations have been interplanted with 

 Hevea and Castilloa. In a similar way 

 Hevea is being planted together with 

 Cola vera and Fourcroya gigantea in 

 Cameroon. 



East Africa and Togo do not come 

 into consideration for the cultivation 

 of Hevea. 



The distances in planting are 16£ ft. x 

 16$ ft., 26£ ft. x 33 ft., and 33 ft. x 40 ft. 

 The tapping of Hevea is done as in 

 Ceylon. The rubber is only produced in 

 sheets, and, of course, the quantities 

 produced are still very small. 



Castilloa blastica. 



The Castilloa plantations supply 

 larger quantities of cultivated rubber 

 at tbe present, because it has been found 

 necessary to tap trees to death as well 

 as to thin them out where they have 

 been too closely planted. Prom lack of 

 labour and in order to reduce the 

 cost of clearing and of upkeep, the 

 trees were planted too thickly, often 

 at distances of 6, 8 and 10 feet apart. 

 The object was to find out in what 

 degree close planting would afford a 

 substitute for shade. The experiments 

 have shown that a distance of 6 or 8 ft. 

 between the plants is too close, as thin- 

 ning out of the trees must be commenced 

 before they are sufficiently mature to be 

 tapped. Further, trees, three to five 

 years old, yield rubber very rich in 

 resin. By planting at a distance of 

 10 ft., with not too luxurious growth, the 

 trees can generally attain an age of six 

 years before it is necessary to thin them 

 out. The rubber is then much better. 

 This method of planting may be recom- 

 mended, or it can be advantageously 

 substituted one of 8 ft. x ll£ ft. 



A certain amount ot shade, afforded 

 by planting suitable trees, appears to be 

 necessory for Castilloa, if the trees are 

 not to become poor and impoverished. 



The cultivation of Cast/Ulna is, as a 

 rule, attended with more difficulties 

 than that of other rubber trees, in spite 

 of its early vigorous growth. 



In New Guinea tapping is done witli 

 a single blade having a semi-circle edge. 

 The tapping system employed is eicher 

 the half — more rarely the complete — 

 herring-bone incision with about five 

 side branches on each side. The main 

 channel is kept shallow, but the side 

 branches are cut with a sharp knife right 

 to the wood. Cuts which lay the wood 

 bare flow far quicker than those in 

 which this is not the case. With regard 



to this, care has to be taken that certain 

 parts of the bark which run parellel 

 with the axis of the trunk remain quite 

 uninjured. 



The latex is first collected in cups 

 and mixed with a considerable amount 

 of water, stirred, filtered, and poured 

 into casks. After the cream has risen 

 to the surface, the water is run off, and 

 after eighteen to twenty hours, with 

 renewed stirring, replaced with fresh 

 water. This process is then repeated 

 once more, On completion of the two 

 treatments the rubber then floats as a 

 thick cake on the liquid. The caogu- 

 lated mass is removed, cut into pieces 

 and passed once through the rollers. 

 By this the rubber is largely freed from 

 moisture antl acquires a high degree of 

 firmness and elasticity. The sheets thus 

 obtained are soaked for a short time, 

 then superificially dried at a moderate 

 degree of heat in the drying-house, 

 pressed into cube-shaped blocks of 

 about £ cwt., and are then ready for 

 transport. Castilloa rubber stands 

 shipment better in the moist state than 

 when quite dry. Long exposure to a 

 high pressure in the press when form- 

 ing the rubbei into balls does not have 

 a good effect upon the quality. The 

 pressing should be done quickly and 

 strongly. Also in washing the scraps by 

 means of washing rollers, the quality 

 will be so much the worse the oftener 

 the scrap has to pass through the 

 rollers. 



Any uncoagulated latex left in the 

 casks after the removal of the rubber 

 layer is skimmed off, and by pouring 

 it into almost boiling water the rubber 

 it contains is made to separate. The 

 preparation of Castilloa rubber is some- 

 what wearisome when compared with 

 Hevea, as the washing of the latex may 

 require two days. 



In Samoa Castilloa alba is cultivated 

 entirely in place of Castilloa elastica. 

 Tapping, however, has not yet com- 

 menced. The C, alba has several 

 enemies, in Samoa a spongy fungus, Hy- 

 menochoete noxia, grows on the main 

 root, and in New Guinea it is attacked 

 by cockchafers and boring beetles. 



Ficus Elastica. 

 The cultivation of Ficus elastica in 

 Cameroon, Togo and the Carolines has 

 not yet passed the first stages. In New 

 Guinea, however, it has become relative- 

 ly extensive, as it offers no difficulties, 

 the tree grows well and the rubber is of 

 very good quality. At first the plants 

 are distanced 18 ft. * 18 ft. This is ulti- 

 mately increased to 36 ft. x 36 ft. Tap- 



