604

Mucilages.

part III.

acetic acid, the components of the tar. The solution has thecolour of Madeira wine, and a sharp empyreumatic taste.

Medical properties and uses. — Tar water is stimulant anddiuretic; but to produce the latter effect, its operation requiresto be aided by bodily exercise. It may prove useful in scurvy,and some cutaneous diseases; but the reputation which it ob-tained on the faith of the judgment of the worthy Bishop ofCloyne 1 has long since been lost, and it is now scarcely everemployed. From Oj to Oij may be taken in the course of aday.

MUCILAGINES.

Mucilages.

Mucilages, correctly speaking, are simple solutions of gumor mucus in water; but the term mucilage, in pharmaceuticallanguage, implies also any solution of a thick and adhesive na-ture, resembling in its appearance the solutions of gum.

MUCILAGO ACACIvE. 2 Lond. Mucilage of Acacia.

" Take of acacia gum, in powder, four ounces ; boiling water,half a pint. Rub the gum with the water, gradually added,until it forms a mucilage."

MuciLago AcAOiE Arabics. Edin. Mucilage of GumArabic.

" Take of gum arabic, in powder, one part ; boiling water,two parts. Digest with occasional agitation, until the gum bedissolved ; then strain the mucilage through linen."

Mucilago Gummi Arabici. Dub. Mucilage of Gum Arabic.

" Take of gum arabic, in coarse powder, four ounces; boil-ing water, eight pints. Digest with frequent agitation, untilthe gum be dissolved; then strain the mucilage through linen."

The straining through linen is very necessary, as the gumis often mixed with small pieces of wood and other impurities.The mucilage thus obtained is viscid, thick, and adhesive;semipellucid, and nearly colourless, if the gum be good. Ithas a faint, peculiar odour, is insipid, and may be kept with-out altering for a considerable time; but at length it becomessour, and acetic acid is formed. The' strong acids act on itas they do on gum; but when diluted, they do not alter muci-lage. Alcohol converts it into a white curd; but proof spirit

1 Berkley's Siris —pas.iivu

z This appellation is certainly exceptionable. It is a mucilage of gum of the Acaciavera. The Edinburgh name is liable to nearly the same objection, except that the spe-cific name of the plant is used, whereas Acacw is the name of the genus. Mucilage dsGomme arabicpie (F.) Schlieim de Arabiche Gummi (C) Muci'agine de Gommaarabica (/.)