Page:The British pharmacopœia.djvu/517

Rh SOLUTION OF LITMUS.

Take of

Boil the litmus with four fluid ounces of the spirit for one hour, and pour away the clear fluid; repeat this operation with three ounces of the spirit; and a third time with the remainder of the spirit. Digest the residual litmus in distilled water, and filter.

SOLUTION OF OXALATE OF AMMONIUM.

Take of Dissolve and filter.

SOLUTION OF PEROCHLORIDE OF GOLD.

Take of

Place the gold in a flask with the nitric acid and six fluid drachms of the hydrochloric acid, first mixed with four fluid drachms of the water, and digest until it is dissolved. Add to the solution the additional fluid drachm of hydrochloric acid, evaporate at a temperature not exceeding 212° F. (100°C.) until acid vapours cease to be given off, and dissolve the chloride of gold thus obtained in five fluid ounces of distilled water. The solution should be kept in a stoppered bottle.