339 



This acid appears to be an isomeric form of abietic acid, if the formula 

 C,„H..„0, be accepted for that substance, although it melted at a considerably 

 lower temperature than ordinary abietic acid. (For much data concerning abietic 

 or sylvic acid, see article in " Allen's Commercial Organic Analysis," Vol. II, 

 Part 3, 1907, page 158; also Dr. Henry's Paper on the " Sandarac Resins," 

 Journ. Chem. Soc, igoi, page 1144.) 



The bitter principle was most pronounced in the neutral ether extract after 

 separation from the acid portion. It was extracted from this residue by water, 

 and afterwards obtained as microscopic needles on evaporation. It appears to be 

 a distinct body, and not directly in combination with the acids themselves. The 

 neutral portion of the resin was Icevo-rotatory, thus agreeing in rotation \\ith the 

 acid of low melting point. 



The general composition of the resin of Araucaria Cunninghamii , as first 

 prepared from the latex, may be stated as follows : — 



Dundathic acid (C.,jH.^.,03) ... ... ... = 14-5 per cent. 



An isomeric form of abietic acid (C.,(,H.,|jO.,) . . . = 62-0 „ (about). 

 Neutral resins, bitter principle, &c. ... ... =23-5 ,, 



Considered from an economic point of view, the exudation of ^4. Cnnning- 

 hamii should have some commercial value for the resin and gum it contains, if 

 collected in quantity. It does not, however, appear naturally to yield an exudation 

 in abundance, so that it would be necessary to systematically wound the trees, 

 cutting quite through the bark, and at the same time forming a box-like receptacle 

 for the material. It might then be collected as it accumulated. 



Experimental. 



The material was collected at Murwillumbah, New South Wales, 28th 

 No^'ember, 1907, and was investigated immediately on receipt at the Museum. 

 It was a semi-opaque, cream-coloured liquid, of a pasty consistency, with lumps 

 of a more solid, resinous-like substance throughout. It had a sour, butter-like 

 odour, and was strongly acid to litmus. On adding water, a thin emulsion was 

 at once formed, and it was evident that the semi-opaqueness of the latex was 

 largely due to the water present and to the suspended resin. It was practically 

 soluble in an excess of hot aqueous solution of carbonate of soda, but mostly 

 separated out again on cooling. The resins were readily and almost entirely 

 extracted from the aqueous latex by ether, and were somewhat soft and slightly 

 aromatic. After removal of the resins the remainder was poured into a large 

 amount of alcohol, when a quantity of a colourless gxim precipitated. On diying, 

 however, this gum became smoky and dirty in appearance from the formation of 

 a higher oxide of manganese. 



