AGRICULTURAL BULLETIN 
OF THE 
STRAITS 
AND 
FEDERATED MALAY STATES. 
No. 8.] AUGUST, 1905. [Vol. IV. 
RESULTS OE THE EXPERIMENTAL TAPPINGS 
OF HEVEA BRASILIENSIS 
At the Economic Gardens at Tjikeumeuh 
MADE DURING I9OO-1904 
By Dr. W. R. TROMP De HAAS. 
By permission of the author, we publish a translation from the 
Dutch of the experiments on Para Rubber conducted in the Econo- 
mic Gardens in Java. The paper was published in Teysmannia, 
Part 10 (1905), p, 182. Thd system of coagulating with alcohol is 
interesting though not practicable commercially on account of ex- 
pense. It will be noticed too that stress is laid on the dryness from 
sun and wind interfering with tapping. The importance of sufficient 
humidity in the estate, especially in the ground, is becoming more 
and more evident and this will have a great bearing on the selection 
of sites for plantations. There is little doubt that the latex is 
formed in the roots and that a larger? proportion of latex can be 
extracted when the tree is turgescent from a liberal supply of water 
absorbed by the roots. Hence it would seem of the greatest impor- 
tance that the roots should be able to obtain a sufficient supply of 
water for the tree, which might not be the case in very dry 
ground. 
We shall here once more shortly review the results wtich we have 
obtained to this day, concerning the tapping of Hevea Brasiliensis . 
They have gradually led us to the methods of tapping which are 
now used by us. m 
In the first year, the experiments made on^the Hevea trees grow- 
ing in the Economic Gardens shewed us that the yield of the latex 
of Hevea Brasiliensis attains its highest point after the tap- 
wounds have been re-opened several times in succession at intervals. 
