133 
TAPPING EXPERIMENTS ON RAMBONG AND 
PARA. 
Professor Dr. A. Weberbauer records in the last December number 
of the “ Tropenpjianzer” some interesting experiments he made in 
Camerun on the tapping of certain species of rubber bearing plants. 
We abstract his remarks on Ficus elastica (Rambong) and Hevea 
Braziliensis (Para). 
In tapping Ficus elastica he used the ordinary tapping knife 
( “ die Kaeuflichen Kautschukmesser ” ). In the outer layer of bark, 
which contains little or no latex, a groove was cut to the depth at 
which the first drops of latex show themselves, then with an ordinary 
penknife a deep cut was made in the bottom of the groove. The author 
claims that wounds in the cambium, which cannot always be avoided, 
will heal more quickly, if caused by the sharp pocket knife than by 
the ordinary coarser tapping knife. 
The weights given are those of well -dried rubber. 
In the first experiment two trees with stems of about equal girth 
were taken. 
In (a) a cut of 16 centimetres (about 6i inches) was made in a 
sloping direction. 
In (b) the cut was 22 centimetres (about 8f inches) and parallel 
with the axis of the stem, that is vertical in the case of an upright 
growing tree. Tire yield from (a) was 2*1 grams (lQOOgrams— 2§ lbs.) 
from (b) 1*2 grams ; so that the sloping cut, though shorter than the 
other, yielded nearly twice as much rubber. 
In another experiment six cuts were made on the same branch 
and on succeeding days, except that a clear day intervened between 
the second and third. All cuts were made at right angles to the long 
axis of the branch, which grew horizontally. The time of day, 9 to 12 
o’clock, was much the same in each case, and so was the iveather. 
The first cut yielded 12*47 grams ; The second, close to but behind 
No. 1 on the same side of the stem, gave 0*87 grams ; The third, on 
the same side as No. 2. and about 4 inches distant from it, yielded 
2*03 grams ; The fourth was on the same side as No. 3 and distant 
about 8 inches, the yield was 2*20 grams. The fifth was on the oppo- 
site side to the previous ones and lay under the first : it yielded 8*80 
grams. The sixth was on the same side of the stem as the fifth but 16 
inches distant from it : yield 2*26 grams. 
The first cut gave more than double as much rubber as the three 
others together which were on the same side of the branch. The 
farther the cuts are from each other the greater is the yield. On the 
opposite side of the stem, the fifth cut gave nearly four times as much 
latex as the sixth, though the distance between them was relatively large. 
Therefore if Ficus elastica is tapped with sloping cuts, and if a good 
number of these are made in a short time, they should, if they lie on 
the same side of a stem or a branch, be made considerable' distances 
apart, otherwise there is only a useless injuring of the tree. In his 
