' r 
36 EEPOET ON THE CAOUTCHOUC OF COMMEECE. 
In ifcaragua the TJIe tree ( Castilloa elctstica , &c.) is tapped in 
the form of a spiral, surrounding the tree at an inclination of 
about 45° (Eig. 4). A single tree often requires 2,000 cuts to 
complete the surrounding. If the tree he large, two such spirals 
are made, either cutting each other or running parallel to each 
other (Eig. 5). This is however a very injurious manner. 
In Par&, Guiana, &c. in tapping the Seringa (Hevece sps.) a long 
perpendicular incision is made from near the base and extending 
high up the trunk. On each side of this line and 
meeting it are numerous small oblique cuts. Some- 
times a basal cut is made extending some dis- 
tance round the trunk on each side of the vertical 
cut (Eig. 6). This mode of tapping, especially if 
made without the basal cut and with slight modi- 
fications to suit particular cases, has much to 
recommend it as it is equally applicable to large 
and small trees, and in the case of the Ficus 
elastica , which is a congregation of stems, and 
where all sides are not equally accessible, it 
can be adopted with ease, whereas the spiral 
incision can only be used where the whole of the 
circumference of the trunk is accessible. In 
the tapping of the stems of Ficus , where deeply 
furrowed, the vertical line alone could be used or diagonal cuts only 
on the side best suited, and in tapping roots one long cut could be 
made so inclined as to form a natural channel with smaller ones 
above it. 
Implements used, — In South America and other countries 
machetes (small axes) or long knives are used. All these are very 
bad, as in their slovenly use the tree is gashed in a frightful manner. 
The huleros in Nicaragua, for instance, before withdrawing the axe 
after a cut is made, press heavily on the handle in order to open 
the wound as much as possible, thus extending the injury to a 
considerable distance. 
In tapping, the greatest care should be taken not to injure the 
CmiJMvm layer. This Cambium layer *is situated on the outside of 
each annual zone, and is a layer of vitally active cells, in which the 
new layers of bark and wood are elaborated and given off. If 
injured, the wood and bark 'suffer and no new bark consequently 
cicatrises over the wound. Mr. Mclvor’s very successful and 
