The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller.

Georg Christian Wittstein

Date:: 1878

Credit: The organic constituents of plants and vegetable substances and their chemical analysis / by G.C. Wittstein ; authorised translation from the German original, enlarged with numerous additions, by Baron Ferd. von Mueller. Source: Wellcome Collection.

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$täte of lead a brownish, gold-yellow colour without any deposit, and becomes colourless with acids; colours chloride of iron dark- brown-green. KlunilllOtanilic Acid. Is obtained in the preparation of rhamnocathartin and is purified by washing, drying, dissolving in ether and evaporating.—Green-yellow, amorphous, easily-friable mass of a bitter and acerb taste, fusible, dissolves scarcely in cold, slightly in boiling water, readily in alcohol and in ether, colours and precipitates the salts of oxyd of iron olive-green, precipitates also slowly tartarated antimony, but not glue. RliaillllOXailtlliu=Ci2 He Oe or C40 H20 O90. Yellow, crystal- line substance of the bark of the root and of the stem, also of the seeds of Rhamnus cathartica and Rh. Frangula and doubtless many other species. Cover the branchlets of Ptli. Frangula with sulphide of carbon and keep for three to four days, evaporate the liquid to dryness, treat the remnant with alcohol, which leaves the fat undissolved, evaporate again and recrystallise in ether.—Citron- yellow, crystalline mass of a dull, silky histre, ^\-ithout taste or smell; fuses at 226° under evolution of yellow fumes, and subli- mates under partial decomposition in gold-yellow needlesj is not soluble in water, dissolves in 160 parts warm alcohol of 80%, and separates from it on cooling almost completely; scarcely soluble in ether, soluble in sulphide of carbon, fixed and volatile oils, in con- centrated sulphuric acid with dark-ruby-red colour and reprecipi- table by water, in hot concentrated nitric acid unaltered; in alkalies with a splendid purj)le colour. Rhaiioilticill ) ^Chrysophanic Acid. Rlieic Acid ) [Rlliliailtllill=::C58 H52 O40 + sHO. Glucosid, discovered by Ludwig in the seed of Alectorolophus liirsutus. To prepare it treat the pulverised seeds with strong, boiling alcohol, evapoi-ate the filtrate to dryness, remove the oil by means of ether, dissolve the residue in water, filter and evapoi-ate to a syrupy consistence. The crystals, which -will slowly form, are to be purified by recrys- tallisatioii.—The R. forms colourless crystals of a bitter-sweet* taste; is readily soluble in water and in alcohol, not in ether; of a neutral reaction. It is not precipitated by subacetate of lead, reduces ammoniacal silver solution when warmed, and separates with acids into glucose and a dark blue-green body, soluble in alcohol but not in water. Heated with sulphuric or hydrochloric acids, R. turns brown, Avhile emitting an aromatic rye odour.] Rliodeoretiii=Convolvulin. Rliodotaiinic Acid=Cu He O7. In the leaves of Rhododen- dron fcrrugineum and probably many of the congeners. Distil the alcoholic extract; mix the remnant with water, filter, preciin-$