DR MACLAGAN ON THE BEBEERU TREE OF BRITISH GUIANA. 427 



To the concentrated mother liquid, from which, in operating on the seeds, 

 the alkalies had been separated, nitrate of baryta is added. A copious dirty- 

 white precipitate falls, which is to be slightly washed with cold water to free it 

 from the brown fluid. It is now to be dissolved in boiling distilled water, filtered 

 and evaporated till a crystalline pellicle forms on the surface. The crystals are 

 best got by skimming them off as they form during the evaporation ; and by repeat- 

 ing the crystallization once or twice, a nearly white product may be obtained. 

 This may be decomposed by sulphuric acid in the usual way ; but I have succeeded 

 better by decomposing a solution of the barytic salt by acetate of lead, and sub- 

 sequently decomposing the precipitate so formed, by sulphuretted hydrogen. The 

 acid liquor thus obtained is to be evaporated to a syrupy consistence, and then 

 placed in vacuo over sulphuric acid to crystallize. It is not, hoAvever, pure, be- 

 ing generally of a brown tint, but it may be purified by dissolving it in ether, and 

 again evaporating in vacuo. I have thus succeeded in procuring it in small quan- 

 tity, in the form of a white crystalline mass with a waxy lustre. The process, 

 however, has not always succeeded well, and I have not yet been able to satisfy 

 myself as to the causes of this difficulty. The acid does not correspond in charac- 

 ter with any hitherto described by chemists. I have therefore called it Bebeeric 

 acid. 



The properties of these several products may now be shortly considered in 

 detail. 



Bebeerine. The process for obtaining and purifying it has been already de- 

 scribed. When its solution in alcohol or ether is evaporated in small quantities, 

 so as to leave a thin layer of residue, it remains in the form of a translucent 

 shining yellow film, but when in mass or in powder it is dull and opaque. It is 

 not at all crystalline. Its alcoholic solution has a strong alkaline reaction on 

 reddened litmus paper. Its taste is strongly and permanently bitter, with a slight 

 resinous flavour, and it evolves feebly a corresponding odour when dissolved in 

 water by the aid of sulphuric acid. This does not seem to arise from any adhe- 

 rent impurity, but appears to be characteristic of the substance. Bebeerine is 

 soluble in five times its weight of absolute alcohol, and it is likewise dissolved with 

 great facility by rectified and by proof spirit. Ether takes up a thirteenth of its 

 weight. It is very sparingly soluble in water, requiring 1766 parts of hot, and 

 6650 of cold water for its solution. 



It will be impossible to maintain with certainty that this substance is chemi- 

 cally pure, until it shall have been subjected to the more rigorous examination of 

 ultimate analysis ; but the uniformity of the product which I have obtained, on 

 many separate trials, both from the bark and seeds, and by processes varying 

 slightly from each other, leads me to believe that it may be regarded as such. An 

 unfortunate accident which occurred in my laboratory deprived me of almost the 

 whole store of what I had prepared for the purpose of analysis ; I have, therefore, 



VOL. xv. PART in. 5 z 



