198 TROPICAL AGRICULTURE 



the trunk being divided into four vertical zones for this pur- 

 pose. The phenomenon of "wound response" is much utilized 

 in tapping Hevea. This phrase refers to the fact that within 

 certain limits the quickly healing surface of the cut in the 

 bark of the Hevea will yield increasing amounts by tapping it 

 for 3 to 5 days, after which a resting period is allowed. The 

 full herringbone system, spiral, half-spiral, and V-shaped 

 incisions have also been used in tapping Hevea. For use in 

 these different methods of tapping more than 50 specially 

 devised tapping instruments have been manufactured and 

 patented. 



Para rubber contains about 95 per cent, caoutchouc, 1.5 

 per cent, resin, 2.5 per cent, protein, 0.5 per cent, ash, and 

 .5 per cent, moisture. 



Ceara or Manigoba rubber (Manihot glaziovii) is a native 

 of Brazil. This tree bears a 3 to 9-parted, usually 5-parted, 

 leaf like that of cassava, instead of the 3-parted leaf as in 

 Hevea. The bark is thin and smooth, the outer layer of bark 

 greatly resembling that of the cherry tree. The Ceara tree 

 reaches a height of 50 feet or more and a diameter of 2 feet 

 or greater. The trunk commonly forks into three or more 

 main branches. In Brazil, the Ceara rubber tree is tapped 

 during a period of 7 or 8 weeks in the dry season. The tap- 

 ping wounds are made at the base of the trunk or on the 

 upper surface of the roots and the latex is allowed to run out 

 on the soil, after which it is collected and washed. Ceara 

 trunks may be tapped by slits or punctures on V-shaped cuts 

 after stripping the outer bark. In Hawaii, a comparison was 

 made of a large number of methods of tapping Ceara rubber 

 trees. The best and most economic results were obtained from 

 stripping the outer bark in narrow vertical slits and making 

 several oblique stabs in the exposed inner bark by means of 

 a flat chisel-like knife producirig an incision about an inch 

 in length. Results almost as satisfactory were obtained by 

 running a wheel pricker up and down the exposed strip of 



