THE CHEMISTRY OF CERTAIN AUSTRALIAN PLANT PRODUCTS. 181 
be an intermediate product in the formation of resin, and 
the Acacias as a group are well known to secrete consider- 
able amounts of tannin. Whether the formation of resin 
in this particular case may also be ascribed to the prior 
existence of tannin, or of polymerised and oxidised hydro- 
carbons, can only be determined by systematic chemical 
studies continued for a sufficient period. 
The resin in question was readily soluble in alcohol, and 
almost entirely soinether. In order to effect its isolation, 
the leaves and terminal branchlets (76° grams) were 
immersed for several periods of one hour in successive 
small amounts of alcohol. After filtering the mixed alco- 
holic extracts, which possessed only a pale brown colour, 
the solvent was expelled by evaporation followed by drying 
at 105°. The residual resin (11°2 grams) amounted to 14°7 
per cent. of the weight of the original material. ‘he resin 
was treated with ether, in which most of it dissolved. The 
filtered ethereal solution was next rendered slightly alkaline 
with alcoholic potassium hydroxide; the mixture was then 
diluted with an excess of water, and shaken in a separating 
funnel with ether, in order to extract the uncombined 
resin. The neutral resin recovered from this ethereal 
extract represented 45°D per cent. of the total resin. The 
aqueous solution was heated to expel the ether, and then 
acidified with hydrochloric acid. The resin acids obtained 
in this way amounted to 34°9 per cent. of the total resin. 
The quantity of tannin extracted by the alcohol was 
insignificant, and the aqueous filtrate from the precipitated 
resin did not reduce Fehling’s solution, thus indicating the 
absence of reducing sugars. I am indebted to Mr. F. W. 
Byrne for assistance in the determination of this resin. 
2. Essential Oil of Boeckea Gunniana. 
The material for distillation was obtained in the month 
of March, at Mount Kosciusko, New South Wales, by Mr. 
