Linum, B.P., Linseed. Linum Contusum, B.P., Crushed Linseed.

Botanical name: 


Related entry: Linseed Oil

Linseed, or flaxseed, consists of the dried ripe seeds of Linum usitatissimum, Linn. (N.O. Lineae), a plant cultivated in most temperate and tropical regions. It is also official in the U.S.P. The fruit is a capsule containing ten seeds. It is collected when ripe, and the seeds separated and dried. Linseed is imported largely from the Argentine Republic, India, and the Baltic. The seeds are small, brown, and glossy, and vary in length from 4 to 6 millimetres. They are ovoid in shape and flat, rounded at one end, but pointed at the other, where the hilum and micropyle are situated. The surface is minutely pitted. When cut transversely, and examined with a lens, the seeds show a white oily kernel, consisting of two comparatively large cotyledons, surrounded by a narrow endosperm. They have a slight odour, and a mucilaginous, oily taste. A variety of linseed with pale yellowish seed coats is known as white linseed. On incineration, linseed should not yield more than 5 per cent. of ash.

Constituents.—The chief constituent of linseed is from 30 to 40 per cent. of fixed oil, but it also contains 6 per cent. of mucilage, which resides in the seed coat, and about 25 per cent. of proteins, together with wax, resin, sugar, phosphates, and a small quantity of the glucoside linamarin. The unripe seeds contain starch.

Action and Uses.—Linseed is used in the preparation of Infusum Lini, which is a demulcent in coughs, especially those forms due to irritation of the pharynx and upper part of the respiratory passages. Infusion of linseed is also given as a demulcent drink in intestinal or urinary catarrhs.


Infusum Lini, B.P.C.—INFUSION OF LINSEED. Syn.—Linseed Tea.
Linseed, 3.5; liquorice root, 1; distilled water, boiling, 100. Solid extract of liquorice is sometimes used instead of liquorice root for flavouring this infusion. Infusion of linseed is a domestic remedy for coughs and bronchitis. Dose.—30 to 120 mils (1 to 4 fluid ounces).
Mucilago Lini, B.P.C.—MUCILAGE OF LINSEED. 1 in 8.
Should be freshly prepared as required; it is used as an ingredient of cough mixtures and in the preparation of Trochisci Lini et Glycyrrhizae, and Chlorodyni.


Crushed linseed consists of the dried ripe seeds of Linum usitatissimum, Linn. (N.O. Lineae), reduced to a coarse powder. It should be recently prepared and have a bland odour, free from pungency or rancidity, when mixed with warm water. The powder should yield not less than 30 per cent. of oil when exhausted by carbon bisulphide. It should be free from starch, and, when incinerated with free access of air should not leave more than 5 per cent. of ash. When kept for some time the oil in crushed linseed becomes rancid, and affects the odour accordingly, while certain cruciferous seeds, which often occur as impurities, produce a pungent odour on the addition of water. The powder should be stored in earthenware or metal vessels. Adulteration with ground linseed cake (left after extracting the oil from the seeds by pressure) and known as linseed meal, is detected by a low percentage of oil and a high percentage of ash. Sophistication with mineral or other oil can be detected by extracting the oil and comparing its properties with those of linseed oil. Crushed linseed often contains traces of starch from unripe seeds.

Constituents.—Crushed linseed of good quality usually contains from 30 to 35 per cent. of oil.

Uses.—Crushed linseed is used in the form of poultice (see Cataplasma Lini) to apply warmth and moisture locally, for the relief of superficial or deep-seated inflammation.


Cataplasma Lini, B.P.C.—LINSEED POULTICE.
Crushed linseed, 28; water, boiling, 72. The poultice may be sprinkled with boric acid previous to application. The poultice mass is usually enclosed in muslin; the surface of the poultice may be smeared with oil to keep it from adhering to the skin.

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.