THE CHEMISTRY OF CERTAIN AUSTRALIAN PLANT PRODUCTS. 183 
characterisation. No sign of a crystalline constituent was 
detected in this oil. 
3. Rubber and Wax from Sarcostemma australe, 
N.O. Asclepiadacece. 
This plant, which occurs in all the Australian States 
except Victoria and Tasmania, is known as ‘“‘Caustic Vine,” 
or “‘Caustic Plant.’’ The material was forwarded to the 
Technological Museum by Messrs. Faulding and OCo., of 
Adelaide, and was collected in Central Australia. 
The leafless stems were pea-green in colour, and coated 
with a silvery, bronze-like material, loosely attached to 
the stem, easily removed, and containing a fair amount of 
a vegetable wax. The thickest stems of the material 
received had a diameter of about 8 mm.; whilst the bark- 
like portion was about 1 mm., and the wooden, pipe-like 
portion just over 1 mm. in thickness. The central, pipe- 
like stem, when freshly cut, was filled with a delicate fibrous 
material through which the latex travelled. When dry, 
this spongy matter shrivelled up, leaving the stem with a 
central channel which in section resembled a pipe-stem. 
As the specimen when received had been collected for 
some time, it had partly dried, but even so the central 
channel still contained a quantity of the milky latex, which 
exuded when the stem wascut. The latex, which was also 
circulating through the bark-like portion of the plant, was of 
the consistency of milk and very adhesive. The small 
amount of material received did not produce sufficient latex 
for an exhaustive examination, although the results 
obtained give a very good idea of the amount of rubber 
likely to be derived from the plant, and of the general 
character of its chemical products. 
The stems were cut into short pieces and the latex col- 
lected. It was then coagulated with acetic acid, and the 
coagulated mass, which represented about 16 per cent. of 
the latex, was well washed with water and air-dried. It 
was thereupon dissolved in chloroform, and the filtered 
solution evaporated so as to form a film on a glass vessel. 
This film, which was of a rubber-like consistency, was 
