46 
of plantation Rambong on the market. An analysis of well 
prepared Rambong compares favourably with the best 
Para, there is very little difference in respect of caoutchouc, 
but the percentage of resin and proteids is slightly highei. 
In Java the Netherlands’ government have rubber 
plantations comprising nearly 15,000 acres of mostly Rain- 
bong. 
In Africa moderate grade rubber is obtained from 
Ficus Yogelii. 
Castilloa elastica (Ule, Central American rubber, or 
eaucho-ball) is a native of. Central America including 
Mexico, Guatemala, Nicaragua, Panama, Honduras, parts 
of Colombia to Peru; and when fully grown is tlie largest 
of all rubber trees. Owing to excessive trapping- and 
very often felling— most of the large indigenous trees are 
already exterminated, but a considerable area m Mexico 
— estimated at 100,000 acres— is already under cultivation 
—a factor which must not be lost sight of m considering the 
future prospects of the rubber market. In tlie West In- 
dies, too, cultivated Castilloa is a rubber which it is ' ex- 
pected will be heard of in the future. The yield of rubbei 
from Castilloa is high, being about the same as Paia and 
varies from 2—16 lbs. according to the size and age 01 the 
tree The latex has an acid re-action and cannot be cur ed 
by smoking. It is coagulated by boiling, or sometmes with 
the addition of alum or salt, or a decoction made fiom the 
stems of the moon-flower. A much improved process toi co- 
agulating the latex by means of separation is now adopted. 
With the aid of a machine rotating about 6000 times per 
minute the particles of caoutchouc are separated m a ew 
minutes into a white layer and can then be taken off and 
dried It is expected that all tlie future plantation Cas- 
tilloa will be prepared by centrifugalismg and a better 
marketable rubber will thus be obtained, as by this method 
of preparation the high percentage of resin can be dis- 
posed of. The nerve or tensile strength of Castilloa is not 
so good as Para, neither has tlie rubber ever obtained so 
high a price. At the time of writing caucho ball (dirty 
scrappy Castilloa) is quoted at 3/10 against 5/4J for fine 
liard Para. 
Tlie attempted cultivation of this species in British 
Malaya can only be described a failure. 
