COLLECTING THE LATEX. 87 



The " Full Spiral " method of tapping has latterly been con- 

 demned by some planters on the ground that it is too drastic 

 and too difficult of accomplishment by untrained coolies. See 

 injurious effect of careless tapping (Fig. I3A). 



Another form of spiral tapping is conducted as follows : A 

 vertical channel is cut for every 17 or 18 inches of the trunk 

 circumference ; spiral curves, each 2 feet long, are cut leading 

 into the vertical incision at a foot apart, the lower side of the 

 spirals being afterwards shaved away as in the full spiral 

 method. The isosceles-triangularly shaped guide can also be 

 used for marking the initial curved incisions by arranging one of 

 the equilateral sides parallel with the vertical channel. The 

 hypotenuse again indicates the direction of the curve, the 

 junction of each with the vertical being regulated at I foot apart. 



As with the herring-bone shaped incisions, it is only neces- 

 sary to have one collecting vessel at the base of each vertical 

 incision. A permanent spout may be fixed at the base of the 

 latter to lead the latex into the collecting vessel, and obviate the 

 injury caused by pressing the collecting cups into the bark 

 which the tapping by V's and similar methods entails. 



What may be described as the " Half Spiral " tapping method 

 may for all practical purposes be considered as identical with 

 that last described, except that the vertical incisions are dis- 

 pensed with. It entails the use of a larger number of collecting 

 cups, as a separate vessel is required to be fixed at the base of 

 each curve in order to collect the latex. 



This extra labour is, however, in a measure compensated for 

 by the large yield in comparison with the amount of bark 

 excised. 



PRICKING. 



With a view of conserving the bark, implements such as the 

 Bowman-Northway puncturing tool marked No. 3 (Fig. 7), 

 and the Macadam comb pricker have been used alternately with 

 paring implements, and it has been stated that, comparing the 

 yield of rubber with the amount of bark excised, the yield has 

 been enhanced. The idea is to puncture the latex-bearing 

 vessels near the cambium. It is found, however, that when this 

 puncturing method is resorted to, the flow of latex from the 

 succeeding paring is appreciably diminished. The importance 



