QUERCETIN.

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the quercetin from these solutions unaltered. The ammoniacal solution ofquercetin becomes brown in contact with air; the alcoholic solution yields,with lime and baryta waters and solution of acetate of lead, orange precipi-tates. Quercetin yields with chloride of tin an orange colour, and a greenwith perchloride of iron. When quercetin, suspended in water, is submittedto the a&ion of chlorine it becomes oxidised and dissolves ; the dry quercetinyields, under the influence of chlorine, an orange matter, probably a substitutionproduct; nitric acid, fuming and common, attacks quercetin, red fumes beinggiven off. The alcoholic solution, of quercetin is decolourised and reduced bynascent hydrogen ; when aCted upon by concentrated sulphuric—or, better yet,fuming sulphuric—acid, quercetin is dissolved, giving rise to the formation ofa yellow sulpho-acid, soluble in water, of an acid taste, and capable of direCtlydyeing woollen tissues yellow without the aid of a mordant.

Quercetin is not even decomposed by a temperature of 350° C., and athigher temperatures is destroyed without any volatilisation. It retains itswater of crystallisation most tenaciously ; 100 parts of air-dried quercetinlose, at 120 0 , 11*5 parts of water, but it requires a temperature of 200° toeliminate the last traces. Quercetin, dried at that temperature and analysed,yielded, according to Hlasiwetz and Stein, centesimally—Carbon, 6o*o and60*3 ; hydrogen, 3*7 and 3*9. Guided by his experiments on the splitting upof quercetin into phloroglucin (C6H6O3) and into quercetic acid (C^H^O^,he assigns to quercetin the formula C27H18O12 (centesimally = C, 60*7; H, 3'4).Schutzenberger and Berteche have proposed for quercetin the formula CnH80 5 ,as better agreeing with the results of the analysis (centesimally =C, 60*0; H, 3*8),and that formula makes quercetin the lower homologue of rhamnetin(C I2 H io 0 5 ). While heating quercetin with anhydrous acetic acid (C6H 4 0 3 )the two last-named chemists obtained a crystalline acetic derivative, of theformula CuHsOs, containing 3 or 4 atoms of acetyl (C 2 H 3 0) substituted for 3 or4 atoms of hydrogen.

Quercetin can combine with potassa, soda, and oxide of zinc : a hot andconcentrated solution of 1 part of quercetin and 3 parts of carbonate of potassadeposits, on cooling, fine needle-shaped crystals, very readily changeable,which may be dried between folds of blotting-paper, but cannot be again re-dissolved in water without undergoing decomposition, unless carbonate ofpotassa be added. The crystals are even somewhat altered by drying in theair at common temperatures. When 5 parts of carbonate of soda and 1 partof quercetin are taken, the corresponding soda compound is obtained. Ac-cording to Hlasiwetz the formulae of these compounds are—C27H18OJ2K2O ;^HjgOiaNaaO. Dr. Schutzenberger prefers the formulae C n H 7 K0 5 andC I1 H 7 Na0 5 .

Hlasiwetz and Pfaundler found, on thoroughly investigating the aCtion ofcaustic potassa upon quercetin, the production of three substances, viz.phloroglucin, quercetic acid, and paradatiscetin, obtained by adding to asolution of 3 parts of potassa in 1 part of water put into a silver dish, 1 partof quercetin, and rapidly evaporating that mixture to dryness. In order toseparate these bodies the alkaline mass is first dissolved in water, and nextneutralised with hydrochloric acid. By this operation the first two bodiesremain in solution, but the paradatiscetin, still mixed with some quercetin, isprecipitated in an impure state; the liquid is next filtered, and, after the