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Materia Medica.

PART II.

balsam is brought to this country in casks^ each containingabout one hundred weight.

4*. Norway Spruce Fir.Officinal, a. Abietis resina. Lond. Resin of the spruce fir.

8. Fix arida. Lond. Resina sponte concreta, vulgo, Pix

Burgundica. Edin. Fix Burgundica. Dub. Burgundy pitch.

The Norway spruce fir is a native of Europe, and of themoist parts of northern Asia; flowering in April.' It is alofty noble tree, rising 150 feet in height; straight, pyramidal,and covered with a reddish scaly bark. The leaves are short,thickly set upon the branches, slightly carinated on both sides,of a dusky green colour, shining on the upper surface, andoften curved: the male catkins are ovate, purplish, andscattered in the axils of the leaves; the female are also purple,and generally terminal: the strobiles or cones are long, nearlycylindrical, greenish before they are ripe, but afterwards pur-ple, and always pendent: the scales, which are arranged ineight spiral rows, have an oval shape terminating in a point,and become ragged at the edges.

The resin or thus of the old London Pharmacopceia exudesspontaneously from the bark of the Norway spruce fir, andconcretes as it exudes. It undergoes no preparation, but isbrought to us in the form of tears or small masses, packed incasks, each containing from one to two hundred weight. Thegreater part comes from Germany, but a small quantity of apurer description comes from France.

Burgundy pitch is obtained by making incisions throughthe bark so as to lay bare the wood. It concretes in the formof flakes at the incisions, which are detached by an iron in-strument once a fortnight during the summer, and fresh inci-sions successively made. The flakes, after being detached,are put into large boilers with a sufficient quantity of water,melted, and then strained through coarse cloths under a press.The greatest quantity is collected in the neighbourhood ofNeufchatel, whence it is brought to this country packed incasks. A factitious sort is made in England, and found inthe shops under the title of common Burgundy pitch. It maybe distinguished by its friability, want of viscidity, and unc-tuosity, and the odour which characterizes the genuine sort.

Qualities. — Turpentines. Although these are producedfrom different species of the pine tribe, and one sort from thePistacia Terebinth us, yet all of them possess the same generaland chemical properties. They have a peculiar somewhat

1 This species of fir is cultivated in Britain, but it Joes not appear to hate been intro-duced before 1739.