APPENDIX. 119 



lead precipitates were either unstable compounds of a saponin with 

 that metal, from which the greater part of the piinciple could be 

 separated by washing, or that they consisted chiefly of easily soluble 

 lead salts of a saponin, or of a lead salt of a saponin mechanically 

 mixed with a saponin precipitated by the action of lead acetate, iu 

 the same manner as we have found certain neutral salts to act. 

 But, on the other hand, it was possible, assuming the existence of 

 more than one saponin -like principle in the plant, that one saponin 

 formed a stable and insoluble lead compound, the other an unstable 

 or soluble salt. And similar remarks might also apply to the 

 barium hydrate precipitate. 



As bearing on these points the following experiments were 

 made:— The amylic alcohol extract was dissolved in water, excess of 

 lead acetate added, and the turbid mixture repeatedly agitated with 

 amylic alcohol. Daring agitation the greater part of the precipitate 

 agglutinated, forming a yellow viscid coating on the bottom and 

 sides of the bottle. This deposit appeared to be very slightly soluble 

 in amylic alcohol. It was soluble in acetic acid, and the acid 

 solution, when agitated with amylic alcohol, afforded an extract 

 which frothed with water, and yielded certain of the reactions of 

 saponin. The viscid deposit from which this extract was obtained 

 Would therefore appear to represent a saponin, which formed a 

 stable lead compound, only slightly soluble in amylic alcohol. The 

 original amylic alcohol solution was next examined to ascertain 

 if it contained any saponin-like principle or not. It was first filtered, 

 and then evaporated to dryness on the water-bath. The residue was 

 yellowish and brittle, and contained a small quantity of lead. The 

 amount of extract was far larger than that obtained from the viscid 

 deposit after decomposition with acetic acid. Lead was removed by 

 dissolving the extract in water and passing H^S. The filtered 

 solution was then evaporated to dryness, the residue reduced to fine 

 powder and repeatedly agitated with ether, which removed some 

 coloui-ing matter and traces of amylic alcohol. The resulting 

 powder was white and free from odour. It afforded the foUowing 

 reactions :-With cold water it formed a slightly opalescent solution, 

 which frothed considerably on agitation. Concentrated H^SO 

 at first faint yeUow, changing to pink, carmine, with^ violet at the 

 edges on standing, and green on the addition of potassic dichromate. 

 Concentrated HNO' colourless, yellow on the addition of dichromate. 



