A New Supplement...: P. Prussian blue. Prussian green. Pterocarpi Lignum. Pterocarpus erinacea. Purple of Cassius. Purpuric acid.

A New Supplement to the latest Pharmacopoeias of London, Edinburgh, Dublin, and Paris, Forming A Complete Dispendatory, Conspectus, and Dictionary of Medical Chemistry, Giving All the Old and New Names, Including the New French and American Medicines, and Poisons; with Symptoms, Treatment, and Tests; as Well As Herbs, Drugs, Compounds, Veterinary Drugs, With the Pharmacopoia of the Vetenary College, Nostrums, Patent Medicines, Perfumery, Paints, Varnishes, And similar articles kept in the Shops; With Their Compositions, Imitations, Adulterations, And Medicinal Uses, Being a General Book of Formulæ and Recipes For Daily Reference in the Laboratory and at the Counter.
Fourth edition, corrected, improved, and very much enlarged.
By James Rennie, M. A., Editor of the Quarterly Journal of Foreign Medicine; the Pharmacopeia Universalis; Author of a Conspectus of Prescriptions in Medicine, Surgery, and Midwifery; the Pharmacopeia Imperialis, &c. &c.
London: Baldwin and Cradock. 1837.
London: Thomas Curson Hansard, Paternoster Row.

PRUSSIAN BLUE. Percyanide of Iron. FERRI PERCYANIDUM. L. Heat to redness dried blood or other animal matters with an equal weight of pearlash till reduced to a paste; dissolve the residue in water, filter, and mix with a solution of one part  proto-sulphate of iron, and two parts of alum; the greenish precipitate absorbs oxygen from the atmosphere, and it is thence tinged to the proper colour. It is obtained pure by adding ferro-cyanide of potassium to sulphate of peroxide of iron in excess, and acidulating with sulphuric acid both largely diluted. The blue precipitate is alternately treated with water, and with water acidulated with sulphuric acid, and dried in a warm place.
 Chemically, the pigment consists of ferro-sesqui-cyanide of the protocyanide of iron.
Good Prussian blue when broken is not glossy, but of a downy dulness in the fracture. Of the samples, that which is lightest will prove the best. (CHAPTAL.) See FERRI PERCYANIDUM. L.

PRUSSIAN GREEN. A celebrated pigment, consisting of an imperfect Prussian blue containing excess of the brown oxide of iron, to which yellow tincture of French berries is added. (FIELD.)

PTEROCARPI LIGNUM. L. E. D. Red Sanders. The wood of Pterocarpus Santalinus. A native of the East Indies, of an aromatic smell, and a bright red colour. Its only use is for colouring tunctures.

PTEROCARPUS ERINACEA. The tree from which KINO is derived.

PURPLE OF CASSIUS. Supposed to be a hydrated double salt of peroxide of tin, being the acid and protoxide of tin and binionide of gold the base.

PURPURIC ACID is procured from purpurate of ammonia (generated by treating uric acid with nitric acid) by digesting it with pure potass and pouring the liquid gradually into dilute sulphuric acid, when the purpuric acid is precipitated. It is a process which does not always succeed. (TURNER.)
Insoluble in water, but it combines with alkalies forming purple-coloured salts.