glucosan

[English, ., glucos ( e ), and an (hydride) (q. v.).] gluer glu-co-side, s . [Eng., ., glucos (e) (q. v.); ide .) Chem.: A name given to compounds which occur naturally in plants from which they are extracted by water, or by alcohol; they cannot be melted without decomposition, and are resolved by boiling with dilute acids into a saccharine substance, as glucose, and another substance which has generally neutral properties. The glucoside can be obtained from the aqueous or alcoholic extract of the plant, by precipitating the other substances by lead acetate, treating the filtrate with H2S gas, and evaporating the filtrate. Glucosides are mostly solid and crystalline substances. They give a red color when heated to 70°, with a dilute solution of gall, and a little concentrated sulphuric acid. [PHLOROGLUCIDE, GUMMIDES, MANNIDES.]