This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Burgundy pitch is a resinous exudation obtained from the stem of Picea excelsa, Link (N.O. Coniferoe), melted and strained.
Burgundy pitch is collected chiefly in Finland, smaller quantities being obtained in the Black Forest and in the Jura mountains. Incisions are made through the bark into the outer layers of wood, and the oleo-resin that slowly collects between the bark and the wood is, after the lapse of some months, scraped out of the incisions, melted under water, and strained.
True Burgundy pitch is an opaque, yellowish brown or dull reddish brown substance, hard and brittle, but gradually taking the form of the vessel in which it is kept. It is strongly adhesive, breaks with a conchoidal fracture, and has a very agreeable aromatic odour, especially when heated. The taste is sweet and aromatic without bitterness.
It is soluble in twice its weight of glacial acetic acid, and readily soluble in alcohol.
Burgundy pitch contains resin and a little volatile oil. The latter appears to consist chiefly of α- and β-picea-pimarolic acids, small quantities of picea-pimarinic and picea-pimaric acids, and resene (juro-resene).
Burgundy pitch is used in the preparation of a few plasters.
Much of the Burgundy pitch of commerce is a factitious mixture of resin, turpentine, and palm oil; it may be distinguished from the genuine by its incomplete solubility in twice its weight of glacial acetic acid (' Pharmacographia').