DR MACLAGAN ON THE BEBEERTJ TREE OF BRITISH GUIANA. 425 



unnecessary to say anything as to the various unsuccessful attempts which I 

 made to obtain a product presenting any appearance of purity. The following is 

 the method by which I have arrived at the results, which I now venture to sub- 

 mit to the Society. 



The bark is boiled in water acidulated with sulphuric acid, as in the ordi- 

 nary process for sulphate of quinine. The fluid so obtained, which speedily be- 

 comes very turbid, is concentrated and allowed to cool. A copious deposit takes 

 place of a light-brown matter, which is a variety of tannin ; and along with it a 

 notable quantity of sulphate of lime, in a crystalline state, is likewise deposited. 

 These are got rid of by nitration ; and to the fluid, which is of a yellowish-green 

 colour, ammonia is added, which lets fall a dark-grey precipitate. This being 

 collected on a filter and washed, is to be dried over the vapour-bath, being at the 

 same time freely exposed to the air, during which process it gradually darkens in 

 colour, from changes induced in tannin adhering to it, until it becomes of a deep- 

 brown, or almost black tint. It is then suspended in distilled water, and sulphu- 

 ric acid in slight excess added, which dissolves the alkaline matter ; the liquid 

 is treated with animal charcoal, and on filtration, is found to be of a clear yellow 

 colour, and strong bitter taste. From this fluid ammonia throws down a precipi- 

 tate, which, when washed and dried, is nearly white, and does not in the least 

 darken by exposure to the air. This is the alkaline matter in the form of a hy- 

 drate. If this precipitate is treated with rectified spirit, it readily dissolves, leav- 

 ing only a little brown flocculent matter, and forming a clear solution of a tint 

 intermediate between yellow and orange. It has a powerful alkaline action on 

 reddened litmus paper, and an intense durable bitter taste. The alcoholic fluid, 

 when evaporated, leaves a shining totally uncrystalline matter, a good deal re- 

 sembling a resin in external appearance, and when in thin layers, quite translu- 

 cent. It is obvious, however, that this is not a homogeneous product, for in some 

 parts it is pale-yellow, in others orange-brown. It is, however, separable into 

 two distinct portions by the action of ether, which, for this purpose, must be 

 anhydrous, and perfectly free from alcohol. That which I used was of density 

 .735, and had been rectified by distillation from caustic potash. 



The ether eventually dissolves by far the larger portion of the alkaline matter : 

 but as the solubility of the alkali in this menstruum is not great, the treatment 

 with ether must be frequently repeated, and ought to be continued, until a portion 

 of the fluid, on being evaporated, leaves no residuum. The ether being recovered 

 by distillation leaves a strongly alkaline and bitter resinous-looking matter, to in- 

 sure the purity of which it should be dissolved in alcohol, treated again with ani- 

 mal charcoal, and evaporated. As thus prepared it should have an uniform homo- 

 geneous appearance, and be, when thoroughly dried, nearly of a canary-yellow 

 colour. In mass it is opaque, and forms a pale yellow powder ; but when evapo- 



