55 
cut in the horizontal direction. ^ Compared with the total number 
of milk-ducts in the layer of bast surrounding the cambium, the 
former number is, of course, insignificantly small. Moreover, we 
must bear in mind that the latex is held in the milk-ducts by capil- 
lary force, and in order to obtain a flow of it from any incision we 
largely depend upon the pressure exerted upon these milk-ducts 
bv the turgescence of the cellulose tissues of the tree. It will 
readily be seen that a vertical incision largely relieves this pressure, 
and consequently the flow of latex obtainable by such an incision 
will not even be proportional to the number of milk-ducts, however 
small, which have been cut into. 
On the other hand very little reflection will show that in applying 
a horizontal incision, not only do we open all the milk-ducts run- 
ning through the area defined by that incision, hut moreover the 
pressure due to the above mentioned turgescence is not in the least 
interfered with, and assists materially in producing a most copious 
flow of latex. It would therefore appear to follow that while verti- 
cal cuts are entirely useless, at any rate, as far as Castilloa elastica 
is concerned, horizontal cuts produce the maximum flow of latex, 
and a system of horizontal cuts therefore offers the best prospects 
for., an effectually tapping of the trees. This, no doubt is so, but 
the circumstance must not be overlooked that a horizontal cut is 
not very satisfactory for the gathering up of the exuding latex, this 
particularly in conjunction with the fact that a Castilloa tree cannot 
be drained by a single small horizontal cut as is, for instance, the 
case with Hevea, but requires a whole series of cuts. This renders 
it desirable that instead of tapping Castilloa with a number of small 
cuts a continuous cut would be preferable and one which drains 
practically the whole area of the trunk. There is only one cut of 
this description, and this is the one known as the spiral cut which 
indeed, has always been largely employed by the native collectors 
exploiting Castilloa trees. I have indeed satisfied myself that the 
flow of latex obtainable from a spiral cut applied at angle of not 
more than 45 degrees produces excellent results as far as the flow 
of latex is concerned. 
There is also the repeatedly advocated system of an ascending 
series of V. shaped cuts, the apices of which are connected by a 
a vertical cut which serves as a channel down which the milk is 
enabled to flow. In the first instance, I consider this vertical cut 
objectionable, as, while it defaces the tree, it does not contribute 
to the yield of latex obtained. Moreover, in the case of the Cas- 
tilloa trees at Las Cascadas this vertical cut would be quite useless 
as the latex yielded by the trees issues from the cuts as a thick 
cream which does not flow, so that in this case the V. shaped cuts 
would only about liave the effect of a double system of crossing 
spiral cuts. 
The next question to be settled was the tool with which the 
above named spiral cuts are to be applied. The instrument in 
universal use for this purpose throughout Central America is the 
machete, a sort cf cutlass. This formidable tool requires very dex- 
terous handling in order to produce a regular cut, and even in the 
T& 
