AUSTRALIAN PlTTOSPORUM. '295 



After treatment with the above solvents, the residue was 

 treated with water for 24 hours, when 4*05 per cent, was 

 dissolved out. This proved to be arabin. 



When treated with soda solution (-1 per cent.), this 

 residue was dissolved to the extent of 2-38 percent., of which 

 My was precipitated by alcohol. On acidifying- with acetic 

 acid metarabin was shown to be present. The remainder 

 was principally colouring matter (?). 



Hydrochloric acid solution appears to have little action 

 upon this residue, only -57 per cent, being extracted. 



The remainder (15*281 per cent.) was insoluble gum and 

 a trace of impurities. 



Suvimary. 



Resin soluble in light petroleum 35'361 



Essential oil 7-599 



Resin soluble in ether 33-120 



„ „ alcohol 1-G39 



Arabin 4-050 



Soda in soda solution ; 1 • 19 i)er cent, is metarabin. . . 2 - 380 



Soluble in hydrochloric acid solution "570 



Insoluble gum and impurities (by difference) 15-281 



100-000 

 Or by actual determination — insoluble gum and 

 i mjjur i ties = 1 1 * 290 



Or a total of 98-999 



Exainiiiation of the Substances removed from the Gnm- 

 .Resin by Ether direct. 



-749 gram of the purest gum-resin obtainable was treated 

 directly with ether, when 75-167 per cent, of resin + essential 

 oil were dissolved out; after heating at 110° C. until a con- 

 stant weight was obtained, the resin was found to be 66-620 

 ])er cent., showing a percentage of 8-547 per cent, of volatile 

 oil driven off. On adding water and again heating no 

 difference was discernible. 



From the residue, alcohol dissolved out 1'462 per cent, of a 

 hard resin. 



Total dissolved by ether and alcohol = 76-629 per cent. 

 The remainder, 23-371, was a clean white gum, which is but 

 slightly soluble in water, but which swells in that liquid. 



The quantity of ash is -71 per cent. 



Comparing the gum-resins of P. bicolor and P. iindula- 

 tum the following points are noticed : — 



1 . The odours are distinct, and apparently characteristic, 



