358 THE BOOK OF USEFUL PLANTS 



produces rubber. To get the greatest quantity 

 of rubber with the least injury to the tree is the 

 modern problem. 



The oldest method of tapping was to cut troughs 

 down the four sides of the tree, and catch in some 

 crude way the flow of sap. Then the plan was to 

 cut four V's as high as the reach of a man standing 

 by the tree. A cup was fastened at the point of 

 each. Other V's cut at intervals drained the area 

 below. This overtaxed the trees. 



The method in general use now in harvest- 

 ing Para rubber is the herringbone system. A 

 vertical trough is cut with alternating side troughs, 

 slanting at 45 degrees and about a foot apart. 

 The cup set at the base of the main trough 

 catches the flow. Each day, when he comes to 

 empty the , cup, the collector cuts a thin slice of 

 bark from the lower edge of each lateral trough. 

 This opens the clogged passages, and renews the 

 flow. The daily cutting is repeated until the side 

 troughs are nearly two inches wide, or until de- 

 crease in the flow indicates that the tree is drained. 

 Six months of rest allows the tree to heal its 

 wounds, and reestablish the network in which the 

 milky juice is found. 



The spiral system, a winding trough around the 

 trunk, is a new method/ that gets the greatest 



