The turpentine obtained by incision from the stem of Abies balsamea, Balm of Gilead Fir. From Canada.

Characters.-A pale yellow ductile oleo-resin, of the consistence of thin honey, with a peculiar agreeable odour, and a slightly bitter feebly acrid taste; by exposure drying very slowly into a transparent adhesive varnish; solidifying when mixed with a sixth of its weight of magnesia.

Composition.-Canada "balsam" contains 17 per cent. of a volatile oil. The resin is dissolved in this.

Dose.-20 to 30 gr.

Canada Balsam is contained in Charta Epispastica and Collodium Flexile.

Action And Uses

Canada balsam is chiefly used for its physical properties. It has been given internally to produce the effects of oil of turpentine in a milder form.

Laricis Cortex-Larch Bark.-The bark, deprived of its outer layer, of Larix europaea, D.C., Abies Larix Rich., the common Larch.

Characters.-In flat pieces; the inner surface yellow and fibrous, outer reddish-brown under a greyish epidermis. Has a faint odour of turpentine.

Substance resembling Larch Bark: Red Cinchona Bark, known by bitter taste.

Composition.-Larch bark yields an oleo-resin, Venetian turpentine, brownish-yellow, tenacious, with an aromatic bitter taste and a pleasant nutmeg-like odour. In its general characters and properties it closely resembles ordinary crude turpentine.

Preparation.

Tinctura Laricis.-1 in 8. Dose, 20 to 30 min.

Action And Uses

Larch closely resembles turpentine in its action, but is more pleasant. It is used (but rarely) in the same class of cases.

Thus Americanum-Common Frankincense. The concrete turpentine of Pinus Taeda, the Frankincense Pine, and Pinus palustris. the Swamp Pine. From the southern states of North America.

Characters.-A softish, bright-yellow, opaque solid, resinous but tough, having the odour of American turpentine.

Composition.-This is apparently the same as the composition of common resin.

Thus Americanum is contained in Emplastrum Picis.

Action And Uses

Frankincense has the same action and uses as resin and its allies just described.