of smoking. On examination in the usual manner, it was found that 
the rubber contained a very high percentage of “ resin” {i.e., matter 
soluble in acetone), amounting to 5*2 per cent on the dry material. 
This proportion of resin is very much ; higher than is usually present 
in Para rubber from the East, but owing to the smallness of the 
samples supplied to the Imperial Institute it was not possible to 
investigate the matter in detail. Subsequently, however, a large speci- 
men of smoked rubber, carefully prepared from the latex of a single 
tree by the same process as that employed for the earlier specimens, 
was forwarded for further examination to the Imperial Institute by 
the Director of the Botanic Gardens at Singapore. 
The specimen consisted of a spindle-shaped piece of smoked 
rubber, weighing 6 lbs., which was almost black externally but whitish 
within when cut. The rubber was rather moist, and a quantity of 
brown viscous liquid was present between the concentric layers. 
An analysis of the rubber gave the following results 
■ \ - • ' \<j ■’ 
Moisture 
Rubber as 
RECEIVED. 
per cent. 
7-4 
Composition of 
DRY RUBBER. 
per cent. 
Caoutchouc ... 
A. 
84.6 
914 
“Resin” 
4.4 
4*8 
Proteid 
2.9 
3*1 
Ash 
0.7 
0.7 
The percentage of “resin ” present in the dry rubber was a little 
lower than that found in the previous samples (4.8 per cent, compared 
with 5.2 per cent.), but was still very much higher than the amount 
usually present in plantation rubber from the East. 
An examination was made of the portion of the rubber dissolved 
by hot acetone, and it was found that a large quantity of a solid cry- 
stalline substance, which was soluble in hot water, was included with 
the resin. The substance amounted to no less than 2.7 per cent, of 
the dry rubber, so that the true figure for the percentage of resin in 
dry rubber was only 2.1 per cent, instead of 4.8 per cent. 
The crystalline substance was submitted to a detailed examina- 
tion and proved to be a carbohydrate, which was identified as laevo- 
methylinosite. The presence of this substance in the aqueous portion 
of the latex of Hevea brasiliensis remaining after the coagulation of 
the rubber has been previously recorded by de Jong, and closely allied 
carbohydrates are known to occur in other latices. The presence of 
such a large amount of the /-methylinosite in this specimen of Para 
rubber is no doubt to be attributed to the method of preparation 
employed, whereby the whole of the solid constituents of the latex 
remain in the rubber, whereas in the usual method of coagulation 
adopted in the East, the rubber separates from the aqueous portion of 
the latex, which retains the soluble constituents in solution. $ 
