- 466 LEGUMINOSZ.. | 
kept for any time. The addition of a = me wil 
prevent this. a 
Chemical composition.—The following account is extracted. 
from the Pharmacographia:—“ Cold water forms with kino a 
réddish solution, which is at first not altered if a fragment of 
. ferrous sulphate is added. But a violet colour is produced as 
‘ goon as the liquid is cautiously neutralized. 
“This can be done by diluting it with common water (con 
taining bicarbonate of calcium) or by adding a drop of solutio 
of acetate of potassium. Yet the fact of kino developing ai 
intense violet colour-in presence of a protosalt of iron, 
most evidently be shown by shaking it with water and iro 
reduced by hydrogen. The filtered liquid is of a brillian 
violet, and may be evaporated at 100° without turning green 
the dried residue even again forms a violet solution with wate 
_ By long Keeping the violet liquid gelatinizes. It is decolorizet 
by acids, and turns red on addition of an alkali, whet 
caustic or ‘bicarbonated.. Catechu, as well as crystallize 
catechin, show the same behaviour, but these solution 
quickly turn green on exposure to air. 
 € Solutions of acids, of metallic salts, or of chrémates road 
‘copious precipitates in, an aqueous solution of kino, Ferri 
3 chloride ae a i dirty,green precipitate, and is at the sam 
time r to a ferrous salt. Dilute mineral acids or alka- 
form 
‘Wane acids o boing for some | > time an aqueous solix 
sheet tannic a p ee is a 
catechu, and yields pei hile treatment the ‘same proaneead 
_ that is to este it afford: co ein when submitted to dr 
istillation, an and | 
en 
