: (. aa2 ) 
This tree is a native of South America, growing abundantly in the 
woeds of Guiana, in the Province of Quito, and along the borders 
of the River of Amazons, in the kingdom of Mexico. 
The younger Linnzus admitted this tree into the Supp. Plant. under 
the genus Jatropa, to which its fruit feemed to bear a greater affinity 
than to that of any other; but by the diligence of Richard’ its cha- 
racters have been found fufficiently different to conftitute a new genus, 
which Schreber calls Siphonia. This we have therefore adopted, ftill 
preferving the {pecific name elaftica. ! 
The fubftance, known by the names India rubber, elaftic gum, 
Cayenne refin, cautchuc, and by the French caoutchouc, is prepared 
from the juice of this tree: as fubfervient to feveral medical or 
chirurgical purpofes, it comes within the fcope of this work, and 
muft therefore prove fufficiently interefting to the medical reader. _ 
This fingular fubftance was little known in Europe till long after 
the commencement of the prefent century ; and its origin and com- 
pofition was firft learned from M. de la Condamine,” who by travelling 
into the interior parts of South America had an opportunity of acquir- 
ing the neceflary information. This active and enterprizing member — 
of the French Academy found that the Caoutchouc was formed from 
the juice of a large tree, which has fince been botanically examined 
and afcertained to be that here reprefented.‘ 
The manner of obtaining this juice is by making incifions through 
the bark of the lower part of the trunc of the tree, from which the 
fluid refin iffues in great abundance, appearing of a milky whitenefs 
as it flows into the veflel placed to receive it, and into which it is 
conducted by means of a tube or leaf- fixed in the incifion, and fup- 
ported with clay. On expofure to the air this milky juice, according: 
to Aublet, gradually infpiffates into a foft reddith elaftic refin ; but 
M. de la Borde, and fome others, affert that the juice: undergoes a 
certain preparation before its infpiffation, which is effe@ted: by a pecu- 
* Vide Rozier obf. ; i Be 8 
> ge: d’un voyage dans Pintaric f a in Mem. de P'Acade 
1751. p. 322. oni i 
rz hit ge from a very complete fpecimen in the poffeffion of Sir Jofeph Banks. 
We muft remark however, that fome other vegetable juices admit bei into 
a {pecies of caoutchouc, of which Frefnau has given ~ accoun ‘§ a er — 
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