400 Transactions. — Chemistry. 



Akt. LXV. — On a Search for the Poisonous Principle of Brachyglottis 

 repanda and B. rangiora. By William Skey, Analyist to the Geo- 

 logical Survey Department. 



[Read hefore the Wellington Philosophical Society, llth February, 1882.] 

 The leaves of Brachyglottis repanda, so well known to be poisonous to 

 horses, etc., I examined some years ago for the purpose of determining the 

 chemical nature of the principle to which this property is referable, but my 

 efforts were unsuccessful, in spite of which I was enabled to report as the 

 result of this investigation that the " poisonous part is not an alkaloid." 



A few weeks ago, however, I was kindly presented by the Hon. Mr. 

 Mantell with a small quantity of a substance which he had observed to 

 exude from a freshly-cut shrub of Brachyglottis rangiora, a variety of the 

 plant distinguished and named by Mr. Buchanan, and stated by him to 

 be a native only of the provincial district of Auckland. This substance 

 proved to be essentially a balsam, that is, a mixture of essential oil and 

 resin, these together amounting to 99*42 per cent. 



As in my former experiment, I failed to find anything in it having the 

 character of an alkaloid, although I extracted, by means of warm water, a 

 small quantity of a bitter substance from it, and found a little nitrogenous 

 matter present. 



Experimenting with the balsam in a tentative way, I soon found that it 

 gives a very remarkable, indeed I may say an unique, reaction for a balsam 

 with acids generally. In warm hydrochloric acid, for instance, it colours to 

 a purplish red ; even at common temperatures, if time be allowed, this comes 

 about. But the most striking effect is produced by heating the balsam with 

 alcohol acidified by any strong acid, a rich deep-blue liquid being thus 

 obtained. Subsequently it was ascertained that the same effect is to be 

 got by using the leaf or the fresh shoots of this plant in place of the balsam; 

 even the old wood can give a feeble reaction of this sort. And it was further 

 ascertained that the variety of this' plant which covers many of the hills in 

 the vicinity of Wellington {Brachyglottis repanda) also behaves in this 

 way with acids. 



It was considered that the substance giving this reaction is likely to be 

 the poisonous part of the balsam, chromatic reaction being obtainable with 

 a great number of organic poisons. I therefore at once took means to 

 isolate both the oil and resin for separately testing. For this the balsam 

 was put in a retort along with water, and heat appUed thereto. The distil- 

 late contained an oil which was partly in solution and partly floating upon 

 it; both the clear solution, as separated from the floating oil, and the pure 

 oil, giving the same reaction as the balsam did in the acids and alcohol. 



