BY J. M. PETRI E. 819 



precipitation with Wagner's solution. From this precipitate 

 the alkaloids were recovered in a clear water-white solution. 

 This solution was extracted with ether until the latter ceased to 

 dissolve any more impurities. By making the solution alkaline 

 with ammonia, the alkaloids appeared as a white precipitate, and 

 were dissolved out with chloroform. The chloroform solution 

 was carefully dried with anhydrous sodium sulphate, and dis- 

 tilled under diminished pressure. A pale yellow viscous residue 

 of alkaloids remained. This residue possessed a peculiar odour 

 like pyridine, a characteristic which was also noted by Dunstan 

 and others at the same stage in the isolation of their solanaceous 

 alkaloids. 



Fommtion of the Atirichlorides — The viscous residue was now 

 dissolved in dilute hydrochloric acid, the solution filtered, and 

 pure gold chloride added to it. The yellow precipitate, which 

 first formed, was redissolved by addition of sufficient water, and 

 by warming, then set aside to slowly crystallise. The sponta- 

 neous evaporation of the solution was continued so long as the 

 bright yellow crystals formed, but towards the end, there 

 separated viscous particles of a yellowish-brown colour, which 

 readily melted on warming the liquid, and were completely 

 soluble in alcohol. This uncrystallisable portion was decomposed 

 and the gold removed, shaken out from alkaline solution with 

 chloroform, and again treated with hydrochloric acid and gold 

 chloride. In this way another small quantity of crystals was 

 obtained, but the greater part still separated as viscous particles. 

 By repeated attempts this could not be induced to crystallise 

 further. 



Fractional Crystallisation of the Aurichlorides. — The whole of 

 the yellow crystals was brought into solution in one per cent, 

 hydi-ochloric acid, and set aside to recrystallise slowly. The 

 superfluid was decanted each day from its small crop of crystals. 

 The melting-point of each crop was determined, and those por- 

 tions having the same melting-points were combined. Each 

 fraction was dissolved and crystallised many times, and by 

 gradually bringing together similar fractions, each of these 

 finall}^ possessed a constant melting-point. 



