ACTION AND USES.--Rhubarb is a stomachic, tonic, astringent, mildly cathartic and cholagogue. Rhubarb is useful where there is a lack of tone to the bowels; used in diarrhoea in small doses, for its stimulating tonic action; as a laxative in large doses or may be combined with other laxatives, to prevent griping in milk-fed animals, or may be combined with bismuth, opium or sulphuric acid, to stop diarrhoea; as a laxative or purgative. The fluidextract or powdered root may be combined with calomel, jalap, etc. SALICINUM--SALICIN A neutral principle (glucoside) obtained from several species of the willow and poplar tree. HABITAT.--Europe, but cultivated in North America. DERIVATION.--Obtained from a decoction of willow bark. Salicin crystallizes on evaporation, after removal of tannin by agitation with lead oxide. It is purified by repeated solution and crystallization. PROPERTIES.--A white, silky, shining crystalline needle, or colorless crystalline powder; odorless, and having a very bitter taste. Permanent in air. Soluble in 28 parts of water and 30 parts of alcohol. DOSE.--Horses and cattle, 2 dr. to 1 oz.; sheep, 1 to 4 dr.; pigs, ¹⁄₂ to 1 dr.; dogs, 5 to 30 gr. ACTIONS.--Bitter tonic, antipyretic, antiferment and antiseptic, somewhat antiperiodic resembling quinine in its actions, but not as powerful. USES.--Used in febrile conditions about the same as quinine, its chief use is in acute rheumatism, for which it is a very good remedy; as a diaphoretic is used in large doses. SINAPIS ALBA--WHITE MUSTARD DERIVATION.--The dried ripe seeds of Sinapis alba Linne. HABITAT.--Southern Europe and Asia; cultivated in temperate climates. DESCRIPTION.--Globular, with a circular hilum; shell yellowish, finely pitted, hard; embryo oily, with a curved radicle and two cotyledons, one folded over the other; free from starch; inodorous; taste pungent and acrid. DOSE.--Horses, 2 to 4 dr.; cattle, ¹⁄₂ to 1 oz.; sheep and pigs, 1 to 2 dr.; dogs, 10 to 15 gr. SINAPIS NIGRA--BLACK MUSTARD DERIVATION.--The dried ripe seeds of Sinapis Nigra Linne. HABITAT.--Same as White Mustard. DESCRIPTION.--Globular, with a circular hilum; shell blackish-brown, or grayish-brown, finely pitted, hard; embryo oily, with curved radicle and two cotyledons, one folded over the other; free from starch; inodorous when dry, but when triturated with water, of a pungent, penetrating, irritating odor; taste pungent and acrid. CONSTITUENTS.--In the presence of water the latter converts the former into the acrid, volatile, official oil of mustard. DOSE.--Same as white mustard. Commercial form of mustard is a mixture of black and white mustard, and constitutes Sinapis. PREPARATIONS OLEUM SINAPIS VOLATILE--VOLATILE OIL OF MUSTARD DERIVATION.--A volatile oil obtained from black mustard by maceration with water and subsequent distillation.