40 THE WHOLE ART OF RUBBER-GROWING 



trees occurred at the rate of J inch in nine months, 

 providing the cambium had not been pierced. 



Upon these discoveries are based the leading- 

 principles which to-day govern the exploitation of the 

 rubber tree in the Mid-East, and although the lead- 

 ing plantations are doing well under the ordeal, and 

 in the mass increasing heavily their monthly outputs, 

 the wiser heads in the industry are nervously asking 

 " Will it last? " Shortly stated, the tapping prin- 

 ciples referred to are : (a) Tapping to commence 

 when the tree has gained a girth, three feet from the 

 ground, of 17 inches; (b) no tapping operations to 

 be carried at a point higher than six feet from the 

 ground ; (c) tapping by bark excision of at least a 

 quarter of the circumference of the tree in one 

 season. 



If disaster ever does come it will be brought 

 about by the extension of the latter principle by 

 greedy and impatient speculators, many of whom, 

 having to justify inflated estimates in their pro- 

 spectuses, are already planning to double the yield 

 of their young trees in the first year of working by 

 excising the bark of a full half of the tapping area, 

 and trusting to luck for what may happen in 

 consequence ! 



