124 Dr. R. D. Thomson's Examination of the Cowdie Pine Resin. 



buted so extensively to our knowledge of the moral and physical con- 

 dition of that interesting British colony. — {See Dieffenhaclis Travels 

 in New Zealand, London, 8co, 2 ^o?s.) 



I am indebted to Mr. Robert Brown for the information that this 

 rosin is derived from the Dammara Australis — a tree which belongs to 

 the natural order Coniferw and division Abietince. — {See also Lam- 

 herfs Pines.) The resin is, I believe, known by the native name of 

 "Cotvdie,^^ and, in consequence, the tree from which it exudes is 

 usually termed the " Cowdie Pine." There is an excellent specimen 

 of this tree in the Glasgow Botanic Garden, on which I have been 

 able to detect distinct traces of a resinous exudation. In the same 

 garden, also, there is a specimen of the Dammara orientalis, from which 

 the dammara resin, previously described by chemical writers, is pro- 

 bably derived ; {Lecanu and Brandes. Tliomsons Veget. CJiem., p. 538 ;) 

 and on the stem of this species, also, I have observed unequivocal 

 proofs of the presence of a resin. The cowdie resin occurs in large 

 masses, from the size of the fist to a much greater magnitude. It is 

 transparent when freshly fractured ; but, as it comes from New Zealand, 

 generally it is slightly opalescent — a character which is said to be 

 produced by the action of water or moisture. The colour of the resin 

 is light amber. It is easily fused, and then emits a resinous or tur- 

 pentine odour. A small portion of the resin dissolves in weak alcohol, 

 but the greater part remains insoluble. The solution in alcohol evolves 

 the smell of turpentine. The resin, when agitated with hot absolute 

 alcohol, forms a fine varnish, which might be found valuable in the 

 arts. A similar result follows its treatment with oil of turpentine. 

 Sulphuric acid dissolves it ; and water, added to the solution, precipi- 

 tates the resin in flocks. 



Resins are usually divided into two classes, and are termed, accord- 

 ing to their characters, acid and neutral resins. The cowdie resin 

 appears to belong to both of these classes. When boiled with spirits, 

 a portion of the resin dissolves, and there remains a white resin, which 

 is insoluble in weaker spirits, but which forms, with absolute alcohol, 

 a fine transparent varnish. That portion of the resin which dissolves 

 in weak alcohol, possesses all the characters of an acid, forming salts 

 with metallic oxides, and is not precipitated by ammonia ; while the 

 precipitate, occasioned by adding water to the alcoholic solution, is 

 quite soluble in ammonia. The alcoholic solution of the acid portion 

 of the resin reddens vegetable blues. I propose to term it JDammaric 

 acid ; while the residual white resin may be called Dammaran, to dis- 

 tinguish it from the Dammarin of Lecanu and Brandes. 



ENTIRE RESIN. 



The entire resin, without the action of any chemical reagent, was 

 pulverized and dried at 212** F., and afforded, in two analyses, the fol- 

 lowing results, when burned with oxide of copper : — 



