Salicinum. Salicin, C13H18O7, official.

Fig. 81. - Juglans: flowering branch; cross-section of fruit.

Salix and Populus, several species.

A glucoside.

Habitat. Europe, N. America; cultivated.

Syn. White Willow, Common European-, Duck-, Huntington-, Salicin Willow, Withe, Withy; Fr. Saule blanc, Salicine; Ger. Weidenrinde, Salicin.

Sa'lix. L. see etymology, above, of Salicaceae.

Pop u-lus. L. poplar, fr. populus, the people - being often planted along the public ways in Rome, where it was called arbor populi, tree of the people.

Plants. - These two juxta-positioned genera are composed mostly of large trees 15-18 M. (50-60°) high, with flexible branches: Salix leaves, long pointed, entire or glandularly toothed; Populus leaves, broad, more or less heart-shaped, ovate, toothed; flowers May, both in catkins appearing before the leaves, dioecious, buds covered with scales, or a varnish; barks of both genera resemble; that of Salix slips from the wood more readily.

Constituents. - Salicin 1-3 p. c, tannin 12 p. c, extractive matter. Salicinum. Salicin. - Obtained by several methods: 1. Add litharge or basic lead acetate to hot concentrated decoction of young bark to remove tannin, gum, extractive; the filtrate contains salicin and some absorbed lead, the latter is separated by adding sulphuric acid and barium sulphide, while salicin, upon concentration of the filtrate, crystallizes out. When basic lead acetate is used, the free acid should be neutralized with calcium carbonate, and then the filtrate evaporated. 2. Boil bark with milk of lime to remove tannin, evaporate filtrate to soft extract, digest this with alcohol, from which salicin will crystallize after distilling off the alcohol. It is in colorless, silky, shining, crystalline needles, rhombic prisms, white, crystalline powder, odorless, very bitter taste, soluble in water (23.5), hot water (3.3), alcohol (88.5), hot alcohol (30), insoluble in chloroform, ether; aqueous solution (1 in 30) neutral, laevoro-tatory, melts at 200° C. (392° F.). Tests: 1. Heat small portion in test-tube until brown, add distilled water (few Ml.; Cc.), + few drops of ferric chloride T. S. - violet color. 2. With sulphuric acid - red color, disappearing on adding distilled water; incinerate 2 Gm. - ash .05 p. c. 3. Heat gently .1 Gm. with potassium dichromate .2 Gm. + diluted sulphuric acid 2 Ml. (Cc.) - fragrant odor of salicylic aldehyde. Impurities: Heavy metals, alkaloids, salicylic acid. Should be kept in well-closed containers. Dose, gr. 10-30 (.6-2 Gm.).

Commercial. - The White Willow (Salix al'ba) and Crack Willow (S. frag'ilis) contain most tannin, the Purple Willow (S. purpu'rea) most salicin, it being even in the leaves, although largest quantity in bark of young wood. Populus al'ba, P. angustifo'lia, P. acumina'ta, P. trem'ula, all yield salicin to a considerable extent.

Preparations. - (Unoff.): May give in powder, pill, syrup, water, or with licorice extract, in small and frequent doses.

Properties. - Bitter tonic, antiperiodic, antipyretic, antiseptic, anti-ferment. Its action is slower, weaker, and depresses heart less than salicylic acid; it is non-toxic, possibly circulates like salicylic acid in the blood as sodium salicylate, and is eliminated chiefly by the urine as salicylic, salicyluric, salicylous acids and saligenin, being first converted in the stomach into glucose and saligenin.

Fig. 82. - Willow bark: transverse section, magnified 15 diam.

Uses. - Acute rheumatism, lower temperature in fevers; relieves pain, reduces.arterial swellings, intermittent (not nearly so effective as quinine), coryza, hay fever, influenza, neuralgia, diabetes. Externally - gangrenous wounds, eczema, cancer, burns, fetid perspiration (applied in solution with borax).

Allied Plants:

1. Populus ni'gra or P. balsamif'era, Populi Gemmae, Balm of Gilead Buds. The air-dried, closed winter leaf-buds, collected in early spring; about 2 Cm. (4/5') long, 3 Mm. (J') thick; imbricated scales, brown, glossy, glutinous (fragrant resin), balsamic, bitter. Stimulating expectorant; ointment for ulcers.

2. Myri'ca cerif'era, Bayberry Bark (root). Dose, gr. 5-15 (.3-1 Gm.); comp. powder (composition powder), 60 p. c, Jamaica ginger 30, capsicum 5, clove 5; tonic, astringent, diuretic.