NOTES ON BARK OF CAItlSSA OYATA. 
281 
be determined. The glucoside, purified by amylic -alcohol, was used 
for the reactions, and some of these are most marked and appear 
characteristic. 
When a small portion is dissolved in concentrated sulphuric acid, 
a yellow colour is at first produced, changing to yellow-brown, 
purplish on the edges after a quarter of an hour, purple after one 
hour, persistent for some time. This fine purple appears characteristic, 
and no trace of green is developed during the colour changes. When 
a portion is dissolved in nitric acid the colour is yellowish-brown, then 
pure yellow, which remains for some time. 
Hydrochloric acid causes hardly any change, except perhaps a 
yellowish colour. 
Aqueous solution gives no reaction with litmus paper (neutral). 
KHO, NaHO, MH 3 to the aqueous solution, slightly yellow but 
very faint colour. 
Ee 2 Cl 6 gives no reaction, or slightly yellowish-brown. 
Basic acetate of lead gives a white precipitate, slow in forming. 
Neutral acetate of lead no precipitate. 
Tannic acid gives a white or light-grey precipitate. 
KI -f I gives a light yellowish-brown precipitate in the aqueous 
solution, and darkens when acidified. 
KBr + Br no precipitate until acidified (yellow). 
AuC 1 3 and PtCl 4 no change. 
Picric acid no change. 
AgNO s cloud, then white precipitate; this gradually darkens. 
CuS0 4 no reaction. 
HgCL no reaction. 
If to the aqueous solution a trace of Ee 2 Cl 6 is added, the colour 
becomes yellow to brown, with a faint greenish tinge, but soon changes 
to purple, being bluish rather than reddish. This is not a satisfactory 
reaction. The most characteristic test is that with K 2 Cr 2 0,. If a 
portion of the dry substance is dissolved in concentrated sulphuric 
acid, stirred, and to the purplish solution K,Cr„0 7 is added by 
dropping a minute fragment into the centre, the colour soon becomes 
sienna-brown, changing to green near the fragment. If now this 
fragment is moved away to one side of the liquid, portions are soon 
seen of a beautiful pure emerald-green colour. This reaction is a good 
one, but it must not be hurried. If an equal quantity of water is first 
added, stirred, and when dissolved H 2 S0 4 added, and then a drop 
of solution of K 2 Cr 2 0 7 stirred into onc-half of the liquid, a most 
beautiful emerald-green colour is soon developed in that portion, while 
the other part remains purple. Even in a dilute solution, if concen- 
trated sulphuric acid is added, and then a drop of solution of lv 2 Cr 2 0 7 
is stirred in, the true emerald-green colour is soon seen, and it 
remains for some time before fading. 
These reactions with sulphuric acid, and with sulphuric acid and 
K 2 Cr 2 0 7 in all solutions, are most marked and should be characteristic. 
The glucoside could not be removed from an aqueous solution with 
petroleum spirit, or ether, or chloroform, either in an acid or alkaline 
solution, with the exception of the chloroform in an alkaline solution, 
which removed a trace. 
