344 



acid was tinally heated to 100-105° C. It was then a colourless powder, and 

 melted at 234-235° C. to a 3'ellow resin. It was dextro-rotatory, and 0-4 gram 

 dissolved in 10 c.c. absolute alcohol, rotated 2-2° to the right in a loo-mm. tube; 

 the specific rotation was, therefore, \a]„ + 55°, agreeing very closely with the 

 specific rotation of the same acid isolated from the resin of Agathis rolmsta. 



The acid was practically insoluble in diloroform and in ether. It did not 

 dissolve in the cold when acetic anhydride was added to the chloroform, but it 

 went into solution on boiling. When cold, one drop of sulphuric acid changed 

 the solution to a ver\' slight pink colour, which altered to a brownisli tint on 

 standing. On titration the following results were obtained : — 



0-1717 gram dissolved in absolute alcohol required 5-1 c.c. dccinormal 

 XaOH to neutralise it, therefore 40 grams NaOH would neutralise 336 grams acid. 



0-141 gram required 4-2 c.c. ^jr NaOH, or 40 grams NaOH would neutralise 

 335 grams acid. 



Analysis gave the following results : — 



0-1554 gram gave 0-4278 gram CO.2, and 0-1383 gram H2O. 



C. = 75-1; H. = g-88 per cent. 

 C._,|H..i.Aj requires 75-84 per cent. C. ; and 9-7 per cent. H. 



The silver salt was prepared in the usual way, and this gave the following 

 results : — 



0-1651 gram sil\-er salt gave 0-0399 gram silver = 24-2 per cent. Ag. 

 0-1518 „ „ „ 0-0372 „ „ = 24-5 „ Ag. 



C2iH..„A^,0.j contains 24-6 per cent, silver. 



The molecular determinations, and the titration results, together with the 

 results of analysis, indicate the formula CoiH^aO,, for the acid of high melting 

 point in the resin of Araucaria Cnnninghamii. The melting point and rotation 

 also agree with Dundathic acid isolated from the resin of Agathis robusta. 



The acid of low melting point, which was present to the extent of over 

 60 per cent, in the resin oi Araucaria Cnnninghamii, was soluble in an excess of 

 alcoholic potash. It was removed from the insoluble pasty salt, water added, 

 and boiled to expel the alcohol. When cold, water was added, and tlic solution 

 acidified with hydrochloric acid and boiled. The separated acid melted in the 

 hot water, but when cold it was a yellow lump of resin. The above jirocess was 

 repeated, but only a very small quantity of the first acid was again obtained. 



The acid of low melting point was purified as follows: — It was powdered, 

 dissolved in the smallest quantity of alcohol, neutralised willi an alcoholic 

 solution of soda, water added and boilrrl to cnjicI the ah ohol. Wlicn cold a 



