132 
XXVIII.—COLOMBIAN INDIA-RUBBER. 
(Sapium biglandulosum, Muell. Arg.) 
[ K.B., 1890, pp. 149-158.] 
The United States of Colombia have long been recognised as a 
subsidiary source of india-rubber. Colombian rubber has been 
generally kn in commerce from the place of export as 
*Oarthagena." It has been supposed ya `= the produce of a 
species of attain and this may to e extent have been 
actually the ca The - arger proportion of "the export fad its 
way to the United State 
In the following Siia e Mr. Robert — formerly 
in eharge of the Cinchona plantations, Jamaica, and now settled 
at Bogota, gives an interesting account of a tree which yisida the 
. india-rubber, known in commerce as “ Colombia Virgen." This 
as the peculiarity, unlike all other known sources of this 
VOD nim of growing at high elevations, and therefore in a 
comparatively cool climate, 
From the indications —— by Mr. Robert B. White, a 
subsequently by Mr. Thomson, there can be little doubt that the 
tree is one of the atta mergi of Sapium biglandulosum, a 
member of the family Euphorbiaceae, to which the trees yielding 
the Para and Ceara rubbers also belong. This wide ly spread and 
a 
Colombia, Venezuela, Guiana and Brazil. The bcnc) which 
it presents in habit are probably as extreme as are to be met with 
in the vegetable kingdom. And it is probable that its rubber- 
producing qualities may be equally variable. In the West Indies 
it exists in forms which are probably conspecific. But though 
abounding in a milky juice it has never been 
regarded in that maim as a source of caoutchouc, at any rate in 
appreciable qualiti 
In British pagas ‘the species occurs in two forms, which have 
been carefully studied by Mr. G. S. Jenma <b. overnment 
Botanist. The form which occurs on the Pomeroon River is 
known in Carib as Touckpong, in Arawack as Cumakaballi. The 
examination of the eenn Are product of this tree, conducted 
at the works of the India-rubber, Gutta Percha and Telegraph 
Works Co., Limited, at Silve vertown, through the courtesy of Mr. 
. W. Silver, F.L.S., were, on the penc. aeren as regards 
its kassat j for any commercial ur as due to the 
p ce of a resinous P whieh seriously deteriorates its 
n, no sort of 
doubt as to the value of. the Colombin SE ts yielded from the 
same species, and this would make it desirable to give the Guiana 
trees a fresh trial. M. Sagot, the well-known Guiana botanist, to 
whom Mr. Jenman’s specimens were submitted, knew nothing of 
the caoutchouc-producing properties of the species beyond the 
fact that the aborigines of the West Indies used the sa sap as a 
bird-lime for ee birds. 
