PARA-RUBBER CULTIVATION 409 



other hand, latex from the adjoining areas might flow in and 

 refill the drained tubes, so that on retapping in a day or two 

 an abundance of latex would exude. The first possibility may 

 represent the behaviour of Castilloa, the second that of Hevea. 

 In the latter tree the time would appear to be too short for 

 any of the increased flow to be accounted for by the formation 

 of new laticiferous elements. Probably in this case an injury 

 causes an inrush of water into the surrounding intact tubes 

 and perhaps also into the severed ones, which will be now 

 plugged by hardened latex. This flow of liquid towards the 

 injured spot may be required for the reparation of the wound. 



The latex which oozes out from a primary tapping of a 

 Hevea tree is thicker, containing less water and more caoutchouc, 

 than that which flows from subsequent tappings ; and further, 

 it appears to give a poorer quality of rubber. In practice it is a 

 disadvantage to have latex of a treacly consistency exuding, as 

 much of it is apt to harden on the tree, before it reaches the 

 receptacle, producing inferior scrap rubber. In fact, the initial 

 tapping is of little value from a rubber-yielding point of view; 

 it only serves as the guide to future work. Sometimes drip-tins 

 are fixed just above the tapping area. These allow water to drop 

 slowly upon the incisions and so prevent the latex in its course 

 down the trunk from drying on the tree. A little ammonia or 

 formalin added to the water makes this device more effectual, as 

 the coagulation of the latex is prevented by these reagents. 



The latex from the second tapping is thus thinner and more 

 copious, and it continues so for many subsequent tappings. 

 The percentage of caoutchouc in the latex resulting from this 

 multiple tapping has, however, never been adequately worked 

 out. Presumably the percentage (roughly 30 to 40) is fairly 

 uniformly maintained for quite a long period (three to four 

 months), but eventually falls, and a thin watery latex results, 

 which does not pay to collect. This indicates that the tree 

 requires a rest. 



Wound-response appears to be a peculiarity of Hevea alone, 

 or to speak more guardedly, it has not been shown to occur, 

 as yet, in any other rubber tree to the extent that advantage 

 may be taken of it in practice. It may exist in a much less 

 marked degree, but this remains to be demonstrated. 



Considering that the laticiferous system of Castilloa is of 

 an essentially different construction from that of Hevea, it is 



