70 



PARA RUBBER 



Furthermore, it must be remembered that the maximum quantity of 

 latex and rubber may be obtained not so much by tapping virgin 

 areas as by taking advantage of the wound response and pricking 

 or cutting the laticiferous tubes when they contain the maximum 

 amount of latex. 



The Wound Response. 



It has been stated that native collectors of Para rubber do 

 not attempt to collect the latex from the first incisions, and that a 

 quantity capable of being collected is only obtained after two or 

 more tappings in approximately the same area. It is certainly not 

 advisable to make the first incision so deep that a good flow of latex 

 is obtained at once ; only small quantities of latex should be expected 

 from the original incisions. The first cuts can be deepened as neces- 

 sity determines in subsequent tapping operations. The flow to the 

 injured part increases gradually, and may reach the maximum after 

 three to fourteen tappings, after which it is said to decline if the 

 wound area is continuously tapped. The first reliable results were 

 obtained by Willis and Parkin, and as the " wound response " is now 

 recognized as one of the most important principles in determining 

 the frequency of tapping, the following digest of Parkin's results 

 is given : — 



The increase in yield from 61 to 449 c.c. of latex by repetitional 

 tapping in approximately the same area is little less than wonderful, 

 and it now remains to determine the interval which must be allowed 

 between successive tappings. The wound response is not evident 

 twelve hours after tapping, but within twenty-four to forty-eight 

 hours is decidedly obvious. These results suggest the advisability 

 of every planter carrying out his own experiments to determine 

 whether it is better to tap every day for the half of each month, 

 alternate days during each month, or only during certain months. 

 Tapping every day, either for the whole of the months when rain 

 is abundant or only during alternate months, has already given 



