4i4 
THE TROPICAL 
AGRICULTUEIST. fJAN. 1, 1903. 
The amount of resin in rastilloa rnbber shown 
above is absolutely unobjectionable, and does net in 
the least affect the quality of the rubber, I am 
quite aware that now and then all sorts of sinister 
actions are ascribed to the presence of resins in India- 
rubber, but the' e is not the least particle of evidence 
to show that they are intrinsic illy detrimental. As 
a matter of fact, in the manufacture of quite a number 
of rnb'~ec goods resins are deliberately added to the 
mixings. 
It is highly interesting to observe that the amount 
of resin increases in the trees from the root upwards, 
as the following table will show : — 
BESINS IN KUBBER DKAWN FROM 
Per cent. 
Trunk ... ... ... 2 61 
Largest branches ... ... 3-77 
Medium „ ... ... 488 
Young „ ... ... 5-t!6 
Leaves ,, .. ... 7'50 
A similar increase is obsfrved the younger the trees 
from which the rubber is drawn : — 
RESINS IN RrBBEH FROM TREES. 
Per cent. 
2 years old ... ... ... 42-33 
3 „ .. ... ... 3502 
4 „ ... 26-47 
5 ,, ... ... ... 1818 
7 „ ... 11-59 
8 „ ... 721 
It will therefore be seen that my advice not to 
tap the treess until they are at least 8 years old 
is not only justified in the interest of the lite and de- 
velopment of the trees, but also in the amount of 
resin which may safely be admitted in rubber of high 
quality. 
There are very few such observations on the amount 
of resin in lubber trees at different periods of their 
life, and in different parts of the tree, but it can 
scarcely be doubted that other kinds of rubber trees 
will exhibit similar conditions, although the amount 
of resin accompanying the rnbber in different trees 
appears to vary not inconsiderable. But they never 
are entirely absent, and 1 am inclined to think that 
the usual view of them as ojidatiou products of the 
india-rubber is altogether erroneous. 
Purity, — As far as can at the present moment be 
seen, the fact is amply demonstrated that it is pos- 
sible to prepare from the latex of Castilloa elastica 
a rubber which for purity is absolutely without a 
rival, and the physical properties of which place it 
at least on the level with the finest grades of Para 
rubber. And this result is obtainable in working 
upon the milk of a tree, which so far has only been 
conspicuous for yielding the worst of all American 
rubbers. This is all the more gratifying, as these 
results are obtained at quite a tiifling addition to 
the cost of production, which addition, on the other 
hand, is compensated for by an increased value of 
the final product by at least 40 per cent. 
Cost of Rubber. — From what 1 have shown in an 
earlier section of this article it will be seen that 
the Castilloa tree should not be tapped until it is 
8 years of age. The coat of clearing the land for 
planting, transplanting the seedlings, and keeping 
the planted plots for seven years clear from under- 
growth, is astonishingly small, and does not exceed, 
at the utmost, £25 per 1,000 trees for the whole period 
until they are 8 years old. If, therefore, at the end 
of the seventh year the trees are tapped for the first 
time, and only half a pound of rnbber taken per 
tree, we obtain from these 1,000 trees 500 lb. of 
rnbber, which at the very lowest estimate would be 
worth at least 3s. per lb. in Liverpool. Deducting, 
therefore, the cost of collection, preparation, and 
shipment of the rubber, a return of about 100 per 
cent, would be obtained in the eighth year. This, 
with careful management, would steadilj^ iaccease for 
p nv^mber of years. 
Cost of Land.— Of course, the cost of the land 
will play a not unimportant part in such a calcu- 
lation. I do not know under what conditions and 
at what price land suitable fjr rubber cultivation 
may be obtained in the various Central American 
States. In Colombia, at any rate in the territories 
adjoiuicg the Isthmus, land is obtained on the old 
Roman principle, '' res nullius cedit prius occupanti," 
or, in elementary English, " first come, first served." 
That is to say, any land not in private occupation may 
be taken legal possession of by " denouncing " it before 
aland commissioner, a very simple procedure involving 
merely paj ment of a nominal registration fee. 
For the maintenance of the title it is sufficient to 
prove the working of the grant. Labour to any 
amount is easily obtainable from Jamaica, and if 
the steady influx from this island Fhould not suffice, 
the authorities of Barbados would be only too glad 
to giant facilities for tie drafting of labour into 
Colombia from their enormous coloured surplus 
population, for whom no woik can be found in 
Baibados. Wages for plantation workers (machete 
men) range at about $ 1.20 per day (Colombian 
money), equal to |0.60 gold, sa.y, 2g., the men finding 
their own food. 
Planting. — In planting Castilloa, it would appear 
that great care is required to make quite sure that 
the setds used, or the seedlings obtained, aie 
really those of the best variety of Castilloa elastica. 
It appears that there are at least three varieties of 
this Castilloa, which are respectively distinguished 
as Castilloa alba, Castilloa negra, and Castilloa rubra. 
There is not the slighest difference between these 
three varieties as regards the general form of the 
tree and its blanches, and also the flowers and 
seeds are in all tliiee apparently identical. 
The above descriptions refer to the colour of the 
bark. The difference even there is, however, so 
small that it requires a practised eye to recognise the 
different varieties. These, differ nevertheless, very 
greatly in their value to the rubber planter. 
Alha.— Castilloa elastica alba produces a thick 
creamy milk. It is the hardiest of all Castilloa trees, 
and suffers very little from the tapping operation. 
It also yields the largest quantity of rubber. The 
baik of this variety is white, with a distinct 
yellowish or pinkish cast. 
Negba. — Castilloa elastica negra is characterised 
by a very rough dark bark. Is yields very readily 
a thin milk producing a good rubber, but the tree 
in tapping easily bleeds to death. 
Rubra. — Castilloa elastica rubra has a reddish bark 
which is very smooth, thin, and brittle ; nor does it 
show the longitudinal furrows which are noticeable 
in the two first-named trees. This variety yields a 
very small quantity of milk, but the rubber obtained, 
from it is good. The tree is very common all over 
Central America, and I am afraid that in a number 
of instances it was this tree which was planted 
instead of the white Casli loa. Indeed, Koschny is 
inclined to think that it is this variety with which 
the experiments in the botanical gardens of Ceylon 
and Java were made which gave such discouraging 
results. 
Shade or Open. — The question whether Castilloa 
should be planted in the shade, or in open land has 
been answered both ways. It is possible that the 
climatic conditions of the district in which the 
plantation is situated may have some influence upon 
this point. However, all the reliable evidence seems 
to show that the trees grow badly in dense forests, 
and produce a poor yield of rubber when grown 
on open ground. They appear to prosper best when 
growing up together with other trees, so that the 
trunk ia always shaded, whilst the top of the tree 
at least, for a certain time during the day, receives 
the direct rays of the sun. From what I iiave seen 
at Las Cascadas 1 entertain no doubt whatever the 
the last named condition is the most favonrabl« 
for the growth of the tieesi 
