142 HENRY G. SMITH. 
debris was washed away. The substance recovered from 
the aqueous alkali, when dry, was brownish in colour and 
was quite elastic. The several particles of the substance 
had adhered together but indifferently, so that when 
stretched the mass was of a stringy nature and not com- 
pact like the dissolved portion. 
Following up this method for obtaining the caoutchouc, 
500 grams of fresh material of H. corymbosa were thoroughly 
extracted by cold ether as before, and then, without treat- 
ing with chloroform, placed directly in a 5% solution of 
potash, and left for 5 days. The material was then very 
soft, and by continued washing and kneading the whole of 
the leaf substance and the stalks were entirely removed, 
the caoutchouc adhering together sufficiently for it to be 
formed into balls. The substance as thus obtained appeared 
to be identical with that similarly procured previously. 
The amount of thoroughly washed and air dried caoutchouc, 
obtained from the 500 grams of material, was 7°44 grams, 
equal to 1°49. The prior extraction with chloroform in 
the first attempt considerably weakened the substance, so 
that it broke up more readily, and consequently more was 
lost in the process of washing. The preparation by alkali 
direct enabled this to be largely overcome, so that the 
loss was much less. The amount extracted by chloroform 
in 5 days was equal to 9°5) of the larger portion obtained. 
The caoutchouc extracted by chloroform was quite elastic, 
and when made into sheet form, by evaporating the chloro- 
form solution to dryness on glass, resembled most markedly 
ordinary sheet-rubber made from the ‘rubber’ of commerce. 
Heated on platinum it melted at a high temperature—above 
250° C. Heated below its melting point it recovered its 
elasticity at once on cooling. The melting point was con- 
siderably above that of the Museum specimens of crude 
Para rubber, crude New Guinea and other commercial 
