CHEMICAL INVESTIGATION OF THE RED POPPY. 213 
of galls, solution of gelatine, dilute sulphuric and muriatic acid, 
produce no effect. The salts of rhoeadic acid are of a brown- 
ish, bluish-gray or violet colour, have no smell, and are most 
of them tasteless, amorphous, and all of them insoluble in abso- 
lute alcohol. The acid is not altered by exposure to the air 
and light, nor by hydrogen gas, although in the decomposition 
of the lead salt it acquires a brick- red colour. On treating the 
solution with chlorine, it becomes yellow, and leaves on evapo- 
ration a slight residue. When rhoeadic acid is boiled with 
dilute nitric acid, it assumes a yellow colour, without any 
evolution of gas taking place. After a time some minute crys- 
tals are deposited, and there remains, on removing the nitric 
acid, a yellowish-brown residue, which yields a brown preci- 
pitate with a solution of acetate of lead. Concentrated 
sulphuric acid, and also excess of caustic potash, convert the 
acid into a blackish-brown mass, which dissolves in a solution 
of potash. When rhoeadic acid is heated over a spirit-lamp 
on platinum-foil, it puffs up, and is carbonized without inflam- 
ing ; on dry distillation, it yields an acid liquid and an empy- 
reumatic oil. 
Papaveric Acid. — To obtain this acid as pure as possible, 
the extract of flowers of poppy, prepared with hot water, is 
digested with carbonate of lead. The liquid filtered from the 
rhoeadate of lead is violet, has neither taste nor smell, is neu- 
tral towards vegetable colours, and contains no oxide of lead. 
Oxalic acid produces no precipitate in it, although lime is de- 
tected in it on reducing it to ash. Some sulphuric acid is 
added to the concentrated liquid, when some gypsum separates ; 
it is evaporated to dr}ness, and the residue treated w T ith alco- 
hol of GO per cent. The rose-coloured alcoholic extract leaves 
the acid on evaporation as a shining amorphous mass, of a 
beautiful red colour. It is deliquescent, has no smell, a slight- 
ly acid taste, is not soluble in ether and absolute alcohol, but 
readily so in spirit and water. Its solution is not rendered 
turbid by acetate of lead, neutral acetate of copper, nitrate of 
silver and perchloride of iron ; alkalies, barytic and lime- 
20* 
