RESIN OF THE OUTER BARK OF MELALEUCA UNCINATA. 237 



resin, but the neutral bodies do not give it, so that it i& 

 peculiar to the acid resin. 



Neutral Resins. 



The ether extract from the resin-salt, when evaporated 

 to dryness, consisted of alight coloured resinous substance 

 of a brittle nature, which melted at about 125 - 130° C. r 

 but the melting point was not sharp, and it evidently was 

 not a single substance. The alcoholic solution was bitter 

 to the taste. The neutral bodies represent about one- 

 fourth of the amount of the resins extracted. 



Action of Nitric Acid. 



Five grams of the powdered resin were treated with 

 40 c.c. nitric acid; dense fumes were at once formed in the 

 cold. The solution was boiled one and a half hours until 

 clear and brown fumes ceased to form. The whole was 

 then evaporated almost to dryness on the water bath, the 

 residue boiled in water, in which it was only partly soluble, 

 and treated with potash. Although crystals of potassium 

 picrate were not formed, yet the after treatment showed 

 that picric acid or an allied substance was present in traces, 

 as it was possible to dye wool yellow. The mass insoluble 

 in potash was of a yellowish colour, and although scarcely 

 soluble in potash, was soluble in hot soda solution, from 

 which it was again precipitated by acids. It was evidently 

 an oxidised product and not a nitro compound, as the test 

 for nitrogen gave negative results. 



In the bark residue small amounts of tannin substances, 

 and a glucoside, hydrolised by boiling acid, were detected, 

 but no other constituent of interest was found. 



