RUBBER CULTIVATION IN THE EAST 539 



this has proved on the whole rather too cold for them. Others 

 were sent to Singapore and elsewhere. 



For many years the Hevea did not seed, and meanwhile 

 much Ceara rubber (Manihot Glaziovii) was planted, but 

 the returns from this were but poor, and the cultivation 

 was given up in most districts, the more so as the same 

 land would do for tea, which was then spreading rapidly in 

 Ceylon. 



Meanwhile, however, the Botanic Gardens, under the late 

 Dr. Trimen, were not idle, and a large plantation was set 

 out, about 1886, from the seed of the forty-six original trees. 

 In 1888, when the latter were twelve years old, Dr. Trimen 

 commenced to tap the largest of them, making V-shaped incisions 

 with a hammer and chisel. In that year this tree yielded 1 lb. 

 13 oz. and it was tapped every second year thereafter till 1896. 

 In the nine years that thus elapsed it yielded an average of 

 \\ lb. a year. This rubber, being simply dried in coco-nut 

 shells, was very dirty. 



The next stage was in 1897, when the writer, perceiving 

 the weak point of the previous experiment, tapped a whole 

 plantation of younger trees, to get an average yield, and 

 found that about 120 lb. an acre might be annually expected 

 from trees twelve years old. At 25. a pound this was esti- 

 mated to give a profit of 27 per cent., and caused a rush to 

 plant Para rubber, the only check being the still prevailing 

 scarcity of the seed. 



At the same time the writer made a discovery which has 

 proved of the greatest importance to the rubber industry, but 

 which is still without a scientific explanation, viz. the " wound- 

 response." If a given area of the bark be tapped a second time 

 within a week or ten days, it will yield a larger amount of 

 latex than at the first tapping, and another tapping may 

 produce an even larger amount. We may illustrate this by 

 some actual figures. Four Hevea trees were tapped at 

 Peradeniya in 1899 at intervals of about a week, and the 

 yields of latex, in cubic centimetres, were 61, 105, 220, 208, 

 255, 290, 276, 253, 264, 275, 255, 262, 328, 449. The experiment 

 had then to be stopped, owing to the departure of the 

 operator for Europe. This is a very remarkable fact, and at 

 once showed the reason for the bad reports which had so 

 often been made of this tree — the experimenters had only 



