ELEMENTS OF MATERIA MEDICA.
730
It
it is procured. In the dried state, it is usually quilled and odourless-should have a bitter and astringent taste.
Composition. —The bark of Salix alba was analyzed by MM- ^tier and Caventou ( Journ. de Pharm. t. vii, p. 123), who obtainedfollowing results:— Bitter yellow colouring matter, green fatty mat ’similar to that found in cinchona, tannin, resinous extract, gum, ^ ’woody fibre, and a magnesian salt, containing an organic acid. , e
These celebrated chemists failed to isolate salicin, which must nbeen contained in their bitter yellow colouring matter, either mix et ,combined with some other matter. Their resinous extract is probaidentical with what Braconnot calls corticin.
I. Tannic acid .—This is the astringent principle of willow bark. Sir H(Elern. of Agricult. Chem. p. 83, 4th ed.) gives the following as the quantities of[impure tannic acid], in the bark of two willows :—■
480 lbs. of bark. lbs. of tan 11 * 11 '
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2. Salicin .—A crystallizable, non-nitrogenous principle, obtained from several S Pof salix. Probably contained in all those whose barks possess bitterness, buquantity varies with the species, the soil, age of the tree, and perhaps the 9e qjji^It is white, very bitter, inodorous, fusible at 2120, much more soluble inthan in cold water, soluble in alcohol, but not so in ether or the volatile oils- [ 0posed, according to Pelouze and Gay-Lussac , of C2 IIa Oi. Herberger consid ershe a saline compound of a vegetable alkali ( salicina ), and an odorous, volatile ®j r)Sulphuric acid dissolves and reddens it: the red solution attracts water from tbe Tl ]eiand deposits a red powder (rutilin of Braconnot). Salicin possesses tonic p r<> P e ^ , lSanalogous to those of sulphate of quina. It is not so liable to irritate the stoffl at _ f ofthe latter. It may be employed in dyspepsia, intermittents, and other diseasewhich sulphate of quina is usually given. The dose is from 10 to 30 grains- - <e uhas administered 200 grains in 24 hours. Salicin may be given in powder, ^with sugar, or dissolved in some aromatic water (Blom, Med. Beobacht. u.BeU r -Salicine, Potsdam 1835).
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Chemical Characteristics.—A decoction of the bark, made 'distilled w'ater, is coloured dark green ( tannate of iron) by sesq ulC l 0 fride of iron; but, made with spring water, dark purple. Soluti ° J1 tgelatin produces a precipitate ( tannate of gelatin) in the decoction ji .
tincture of nutgalls causes no turbidness. A strong decoction ofbark, containing much salicin, is reddened by concentrated snip * 11
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acid
Physiological Effects.— Willow bark possesses both bitternessastringency. It belongs, therefore, to the astringent-tonics, whose eh- ^have been already noticed (p. 80). It is less apt to disturb the stoi«athan cinchona, but its tonic and febrifuge powers are less than the l atVogt {Fharmakodynamik, 15d. ]. S. 658) ascribes to it balsamic Pperties.
Uses. —It has been employed as an indigenous substitute Aggchona. The indications for its use, therefore, are the same asfor the latter. It is given in intermittents, dyspeptic complaints acC ^ V 0panied with or dependent on a debilitated condition of the di.A'^ jorgans, passive hemorrhages, chronic mucous discharges, in the stafe'^convalescence after fever, and as an anthelmintic. As a local astrmg ^the powder or infusion is sometimes employed ; but there are many &efficient remedies of this kind.
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