3io 
and the fumes evolved will pass through the long atap shed 
mentioned above, in which a number of young plants of Para 
rubber ( Hevea braziliensis), Rambong {Ficus elastica ) and Inga 
saman {Pithecolobium saman), grown in pots, are placed at intervals. 
The ore will be completely calcined and the effect on the plants 
studied pathologically and otherwise. 
If possible, the furnace gases will be analysed to ascertain 
the percentage of arsenious acid and sulphur dioxide. 
I am of opinion that the -sulphur dioxide in the fumes from 
the furnaces working in the various parts of the States causes the 
greater amount of damage to vegetation, especially at a distance 
from the furnaces, as it is widely dispersed by prevailing winds, 
whereas the arsenious acid would be rapidly condensed after its 
^xit from the furnace chimney. 
To demonstrate the correctness or otherwise of this view* 
attempts are being made to condense the arsenic in the 
experimental model furnace and allow only the sulphur dioxide to 
escape. 
The furnace and accessories for carrying out this investi- 
gation are now complete and the results will be embodied in the 
report for 1907. 
Laboratory Investigations. 
Owing to the non-equipment of the laboratory in the 
Institute for Medical Research for agricultural chemical 
investigations and the ladk of apparatus fill quite recently, no 
experiments such as soil or rubber analyses or investigations of 
the agricultural produce of this country have so far been 
undertaken. 
Anti-Opium^ Drug. 
Preliminary experiments were carried out with samples of the 
drug now being distributed in various parts of the States for 
curing the opium habit. Samples of the decoction prepared from 
the plant used, and a number of specimens of the plant were 
received, when the anti -opium movement first commenced on a 
large scale in Kuala Lumpur. The plant is Combretum 
sundaicum, a member of the natural order Combretaceae, to which 
family belongs the genus Terminalia, some species of which are 
used for their tanning properties. The drug, which is essentially 
an extract of the leaves and twigs of the plant, first roasted in 
shallow' iron pans over charcoal fires, and then boiled in 
a definite volume of w'ater and evaporated to a known volume, is 
found to vary somew'hat in composition, and samples I have 
