i6o PLANT AND ORGANIC CHEMISTRY 
orated over a water-bath until all odor of sulphuretted hy¬ 
drogen was dissipated. A part of the lead sulphide filtrate was 
mixed with lime-water, and a precipitate formed not com¬ 
pletely dissolved by acetic acid. The remainder of the lead 
sulphide filtrate was allowed to evaporate over sulphuric acid. 
The residue consisted of a mass of fine crystals radiating from 
a centre. 1 
The crystals gave a very acid reaction when placed on moist¬ 
ened blue litmus paper. They turned black and left a residue 
when heated on platinum foil, and the residue "was slowly 
dissolved by nitric or hydrochloric acid. The quantity of resi¬ 
due was very small, and no effervescence was observed. The 
melting-point of the crystals was taken. A small quantity was 
placed in a tube with thin walls, and gradually heated; at 
150° C. the substance sublimed, leaving a white, cloudy stain 
on the inner surface of the tube; at 190° C., this cloudy stain 
changed to a pale green spot, and with increasing tempera¬ 
ture to 210 0 C., no further change was noted. Dry sodium 
carbonate was added to an aqueous solution of the crystals, 
and a slight effervescence was observed. Some iron was sepa¬ 
rated which possibly was in combination with the crystalline 
principle. Negative results followed tests for formates, ace¬ 
tates, malates, tartrates, citrates, phosphates, oxalates, alka¬ 
loids, and glucosides. 
The amount of glucose present in the aqueous extract was 
too small to determine quantitatively. Negative results for 
tannin. 
Extract (4), the Yellow Base 0} the Leaf. 
The residual powder from the alcoholic maceration was 
dried and replaced in the percolator. Cold distilled water was 
allowed to percolate slowly through the powder. The aque¬ 
ous extract was slightly acid in reaction. A known measure 
1 The material used in this analysis of the green part of the leaf was quite 
dry and powdered readily. A previous examination of the fresh leaves gave 
more satisfactory quantitative results. A gum was extracted which promises 
to be of interest for a future study, and the crystals separated from the lead 
sulphide filtrate are to be further investigated. 
