Burgundy Pitch. Pix burgundica.
Burgundy Pitch. Pix Burgundica. Poise de Bourgogne, Poix des Vosges, Poix jaune, Fr. Cod. Poix blanche, Fr. Burgundisches Pech, Burgunder Harz. Wasserharz, G. Pece di Borgogna, It. Pez de Borgona, Sp.—Under the name of Pix Burgundica was formerly recognized both by the British (1898) and by the U. S. (1890) Pharmacopoeias, "the resinous exudation obtained from the stem of the Picea excelsa Link., melted and strained." Br., 1898.
Picea abies (L.) Karst. or P. excelsa Link. (Fam. Pinaceae), commonly known as Norway spruce, is a lofty tree, rising sometimes one hundred and fifty feet in height, with a trunk from three to five feet in diameter. The leaves, standing thickly upon the branches, are short, obscurely four-cornered, often curved, of a dusky green color, and shining on the upper surface. The male aments are purple and axillary, the female of the same color, but usually terminal. The fruit is in pendent, purple, nearly cylindrical strobiles, the scales of which are oval, pointed, and ragged at the edges. This tree is a native of Europe and Northern Asia, and is cultivated in the United States as a shade tree. Commercially Burgundy pitch is derived not only from the Norway spruce, but also from the Abies picea or European silver fir tree. To obtain the pitch, portions of the bark are removed so as to lay bare the wood, or perpendicular grooved channels are cut, and the flakes of concrete resinous matter which form upon the surface of the wound, having been detached by iron instruments, are melted with water in large boilers, and then strained through coarse cloths. It is called Burgundy pitch from the province of that name in the east of France, although whether it was ever produced in that province is uncertain. It is chiefly collected in Finland, the Schwarzwald, Austria, and the Bernese Alps. A factitious Burgundy pitch is made by melting together common pitch, rosin, and turpentine, and agitating the mixture with water, which gives it the requisite yellow color. Its odor is different from that of the genuine. Hanbury gives as a test of true Burgundy pitch that it is almost entirely soluble in twice its weight of glacial acetic acid while the factitious article similarly treated forms a turbid mixture quickly separating into a thick oily liquid above and a bright solution below.
The resinous exudation from Pinus sylvestris is sometimes offered as Burgundy pitch, but Hirschsohn (Ph. Z. R., xxiv) states that it is possible to distinguish the resin of Picea excelsa by its being only partially soluble in ether, chloroform, and solutions of salts of ammonium, sodium carbonate, and borax, which dissolve completely the resin of Pinus sylvestris. The resin of Picea excelsa is also precipitated by the addition of water from its sulphuric acid solution in red violet flakes, while Pinus sylvestris resin precipitates white.
As brought to this country, Burgundy pitch is generally mixed with impurities, which require that it should be melted and strained before being used. In its pure state, according to the U. S. P., 1890, it is "hard, yet gradually taking the form of the vessel in which it is kept; brittle, with a shining, conchoidal fracture, opaque or translucent, reddish-brown or yellowish-brown, odor agreeably terebinthinate; taste aromatic, sweetish, not bitter. It is almost entirely soluble in glacial acetic acid, or in boiling alcohol, and partly soluble in cold alcohol." U. S., 1890. It is very fusible, and at the heat of the body softens and becomes adhesive. It differs from turpentine in containing a smaller proportion of volatile oil. Instead of the sylvic acid of ordinary rosin, it contains an isomeric acid, which has been called pimaric acid, melting at 148° to 149° C. (298.4°-300.2° F.), difficultly soluble in cold but readily soluble in boiling alcohol, and also soluble in ether. According to Perrenoud, its formula is C40H54O4, but Vesterberg (Ber. d. Ghent. Ges., 1885, p. 3331) showed it to be a mixture, and has since (Ibid., 1886, p. 2167, and 1887, p. 3248) prepared from it two isomeric crystalline acids, a dextropimaric acid and a laevopimaric acid, both of the formula C20H30O2; with these is mixed a varying amount of an amorphous resin acid known as pinic acid.
Applied to the skin, in the shape of a plaster, Burgundy pitch acts as a gentle rubifacient, producing a slight inflammation without separating the cuticle. Sometimes it excites a papillary or vesicular eruption, and we have known it to act as a violent irritant, giving rise to severe pain, swelling, and redness, followed by vesication and even ulceration. It is used chiefly in chronic rheumatic pains, and in chronic affections of the chest or abdomen, which call for a gentle but long-continued revulsion of the skin.