146 THE RUBBER TREE BOOK 



It is very doubtful, however, whether Heveas would long sur- 

 vive the continual girdling involved in the operations of full- 

 spiral tapping. In any case planters soon became fully con- 

 vinced that the system was too drastic and too dangerous, and 

 it was finally entirely abandoned. 



The systems of tapping in general use in the present day, 

 while often too severe, are at least a good deal less severe on the 

 stamina of the trees than the full-spiral system was. The full- 

 herring-bone, the half-herring-bone and the basal V, or modifi- 

 cation of these, are the most popular. 



It is only in cases where, from former ill-usage, the bark 

 of trees is too rough for ordinary methods that single small V 

 cuts are ever employed nowadays. 



Both the herring-bone and the half-herring-bone systems 

 of tapping have been naturally evolved out of the original V 

 tapping. With one V cut above another it was a natural thing 

 to connect two or small channels so that one cup would prove 

 sufficient to serve several cuts. In course of time the V cuts 

 were widened, lengthened, and, being connected by channels, 

 became a series of symmetrical, broad V tappings. In order 

 to interfere as little as possible with the circulation of plant- 

 food through the bark, the V cuts were so adjusted as to form 

 the full-herring-bone system. 



Still later, the full-herring-bone system being thought to be 

 severe upon the trees, and not allowing a sufficient time for 

 bark renewal, the half -herring-bone system, at present in 

 general use on so many estates, was introduced. By this 

 system only half the amount of bark is used up which was 

 excised under the full-herring-bone system. Such, in few 

 words, is a brief resume of the evolution of tapping methods up 

 to the present date. The last word on the subject has not yet 

 been written and further changes are in view. 



The majority of the laticiferous vessels in the trunks of 

 the Hevea trees are found just outside the cambium. It is 

 important, when tapping, that the knife should reach these 

 vessels in order to obtain a good flow of latex, but that at the 

 same time the very greatest care should be exercised by the 

 coolies not to wound the cambium. 



Where wounds have been made there is nearly always a 

 swelling of the stem of the tree at the wounded spot. This 



