APPENDIX, 119 
lead precipitates were either unstable compounds of a saponin with 
that metal, from which the greater part of the principle 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 mechanicall 
mixed with a saponin precipitated by the action of lead acetate, in 
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, During agitation the greater part of the precipitate 
agglutinated, forming a yellow viscid coating on the bottom an 
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 itcontained 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 HS, The filtered 
solution was then evaporated to dryness, the residue reduced to fine 
powder and repeatedly agitated with ether, which removed some 
colouring matter and traces of amylic alcohol. The resulting 
powder was white and free from odour. It afforded the following 
reactions :—With cold water it formed a slightly opalescent solution, 
which frothed considerably on agitation. Concentrated H*S$0* 
at first faint yellow, 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, 
