385 



weight of 332, the formula being C21H3.2O3. If these acids are eventually shown 

 to be similar in origin, then the differences in molecular weight may, perhaps, be 

 traceable to the prolonged influences exerted during the process of fossilisation. 

 It would be interesting if, on further investigation, it becomes possible to show 

 whether these changes do take place with the acids of these Coniferous resins, and, 

 if so, in what direction. 



The name Dundathic acid is proposed for the acid of high-melting point, 

 as it was first obtained from Agathis robusta, the " Dundathu Pine." We 

 have isolated this acid from the resins of both Agathis robusta and Araucaria 

 Cunninghamii, and although the acid of low-melting point in the resin of Agathis 

 robusta was dextro-rotatory, that of the corresponding acid in the resin of Araucaria 

 Cun7iinghamii was laevo-rotatory, yet, the Dundathic acid from the resin of the 

 latter tree was dextro-rotatory like that from Agathis. The neutral constituents 

 of the resins of both plants agree in rotation with that of the acid of low-melting 

 point. This seems to indicate a somewhat close connection between those resinous 

 bodies not acids, and those that contain a carboxyl group, and an exhaustive 

 investigation of these neutral bodies might throw some light upon the formation 

 of the resins themselves, both acid and neutral. The bitter principle was also 

 largely concentrated in this portion, and the aqueous solution, after the slow 

 deposition of the neutral bodies from an alcoholic solution, was intensely bitter. 

 Dundathic acid is evidently formed from material common to both Agathis and 

 Araucaria, and in a similar manner, because the physical and chemical characters 

 of the acid from both trees were in agreement. 



The acid of low-melting point, of which the resin of Agathis robusta 

 principally consisted, did not crystallise by any method, but always appeared to 

 separate in an amorphous condition. It was, however, precipitated from an 

 aqueous solution as a soda- salt, and was separated almost completely in this 

 way, after the Dundathic acid had been removed. A peculiarity which takes 

 place with this acid, and which is worthy of notice, is the slow increase in melting 

 point after separation from the other constituents of the resin, until the final 

 melting point, 101-102° C. is reached. When first prepared, this acid melted at 

 77° C. ; after the lapse of about two weeks the melting point had increased to 88° C, 

 and after one month to gg° C. After this increase in the melting point had been 

 detected, a fresh sample of the resin was prepared, and this also melted at first at 

 yj° C, after one week at 83° C, after two weeks at 8g° C, after three weeks at 

 g6° C, after four weeks at g8° C, after five weeks at gg-ioo° C, and after four 

 months 101-102° C. (The method of taking the melting-points of these resins was 

 to place a small portion of the powder on a micro-slide cover-glass, and float this 

 on a vessel of mercury of sufficient depth to entirely cover the bulb of the 

 thermometer.) We propose the name Dundatholic acid for this constituent of 

 low-melting point isolated from the oleo-resin of Agathis robusta. 



2B 



