514 . THE TROPICAL AGRICULTURIST. (Feb. 2, 1903. 
2, The effect of wounding the tree on the flow o 
the latex ! 
(a). The number of times the incisions can be 
advantageously renewed. 
(5). The length of time that should elapse 
before renewing the incisions. 
Preparatory to tapping, that part of the trunk it is 
intended to work should be well cleaned of all loose 
particles of bark and dirt. In old trees the rough 
outer bark may be shaved off with a blunt knife and 
then rubbed down wHh the husk of a coconut ; but in 
the case of young trees where the bark is not so thick 
and rough, a good rubbing over with a coconut husk 
will suffice. It cannot be too fiimly borne in mind 
that foreign matter of every description decreases the 
value of the prepared rublDer, and every endeavour 
should be made to avoid its inclusion from the com- 
mencement. 
When tapping trees in isolated positions or on the 
edge of a plantation, the shady side of the tree should 
be selected, as the sun has the effect of coagulating the 
latex on the wound, thereby preventing a further flow 
and adding to the percentage of " scrap" or second 
grade rubber. 
(a). Instruments employed.— The instruments used 
during these experiments were an ordinary five-eighth 
inch wood chisel and wooden mallet, and a sharp 
pruning knife. The chisel and mallet were ultimately 
discarded in favour of the knife, as it was found that 
with the latter the work could be done quicker and 
better ; while there was not quite the same danger ot 
cutling into the wood, thereby causing permanent 
injury to the tree. Whatever form of knife is used, if 
should be kept very sharp so as to enable the operator 
to make as clean a cut as possible ; any tearing of the 
bark resulting from the use of a blunt instrument will 
tend to close up the cells and prevent a free egression 
of latex. 
The collecting vessel used was a tin cup, about the 
size and shape of an ordinary cigarette tin, to which 
was affixed a metal lip. This lip being filed at the 
edge pierces the bark, rendering impossible any escape 
of latex between the tree and the collecting receptacle 
avoids the necessity of the use of lutiug material. The 
tin is also supported by this means so that nails, wire, 
etc., are unnecessary. 
{h). The Icind of incision. — The laticiferous or milk- 
producing tissue is composed of a number of vessels or 
tubes which by constant branching I anastomosing) 
have formed a complete network of tissue. In some 
trees, this system of communicitior, between the cells 
is only developed to a very small degree ; while in 
others— notably in the Dichopsis spp, which furnish the 
gutta-percha of commerce, the cells containing the latex 
remain isolated. The more completely this system is 
developed the easier it becomes to extract the latex, as 
it is evident, that other things being equal, a less 
number of incisions will be required to extract a given 
quantity ot latex. 
The vessels constituting this tissue are chiefly distri 
buted thoroughout the phloem or inner layer of bark' 
80 that whatever form the incision takes, it must be 
sufficiently deep to cut through this layer. Immedi- 
ately beneath the laticiferous tissue lies a layer of ac- 
tive cells known as the cambium, and the operations 
should be conducted with care so as to incur as little 
injury to this layer as possible. I have found that it 
is practically impossible to cut through the milk-pro- 
ducing tissue without injuring, at least to some extent, 
the cambium ; but fortunately the tree is very hardy 
in this respect, so that if ordinary care is exercised, 
po serious cousequeace result, 
The thickness of the bark varies from J to 3-8 of an 
inch, gradually thickening as the base of the tree ia 
approached. 
In actual practice the object to be attained is to 
puncture the maximum number of the laticiferous 
tubes while doing as little injury to the tree as possible 
and as these tubes run more or less longitudinally, it 
is clear that a horizontal or an oblique incision will 
puncture more tubes than a vertical one. The diffi- 
culties arising in collecting the latex from a horizon- 
tal incision are obvious, so it remains to be seen what 
form the oblique incision should take / whether it ia 
advisable to make a single incision (/), or a double 
incision (V), or a number of double incisions feeding 
a central vertical channel and forming what is known 
as the •' herring-bone " incision. 
Experiments have been conducted at S'tiawan, 
Perak, with a view to ascertaining the difference in 
yield by these various methods, and the result of 
tapping five trees with single oblique incisions is 
shewn below. The inci?ions were made 6 inches apart, 
ranging from the ground to a height of 6 feet up the 
trunk, and in each case were 6 inches long, running at 
an angle of 30 degrees with the perpendicular. 
Age of trees 9 years Mean girth at 3 feet 
from base 4 feet 
2 inches 
120 incisions yielded ... 23'75 ounces of dry 
rubber 
Average yield per incision '19 „ 
Twelve months later the same trees were tapped 
with double oblique incisions, the two lines forming 
the V being in each case 6 inches long. As in the 
former experiment, the incisions were equally distri- 
buted over the first 6 feet of the trunk, commencing at 
the base, The result was : — 
Age of trees, 10 years. Mean girth at 3 feet 
from base 4 feet 
3 inches. 
120 incisions yielded . , 44-25 ounces of dry 
rubber 
Average yield per incision -Se „ „ 
Thus it will be seen that the V incisions gave consi- 
derably more, almost double, the amount obtained 
from the single incisions ; but as twice the amount of 
labour was required and twice the amount of injury 
inflicted upon the tree, the result may be said to be 
slightly in favour of the former method. The reason 
the yield is not quite in proportion to the labour 
expended, or rather to the surface exposed, is due to 
the fact that the two lines forming the V become so 
close to each other as they approach the base of the 
incision, that they probably puncture the same 
tubes. 
We have now to compare the V incision with the 
herring-bone incision, which is practically the same 
principle, except that in this case there are 
a number of V incisions feeding a vertical 
channel, the latex being conducted by the oblique 
incisions towards the central channel at the base of 
which is placed the collecting tin. The feeders should 
be made to join the vertical incision at an angle 
sufficiently acute to enable the latex to escape freely— 
say 40 to 45 degrees, and care should be taken that 
these incisions do not join the central incision opposite 
to each other, or the result will be an ugly wound 
(Fig, B, a) which will take a considerable time tQ 
heal. 
