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DYEING AND CALICO PRINTING.

mentioned yields a body, j O5. This sugar is isomeric with

mannite and dulcite, and has been named isodulcite.

Hlasiwetz and Pfaundler state that there exist various kinds of quercitrin,which differ by the nature of sugar in combination, while the composition ofthe other constituent, the quercetin, is constantly the same. Quercetin, firstdiscovered by M. Rigaud as the product of the splitting up of the quercitrin,is, according to Dr. Bolley, also found either isolated or in a glucose com-bination in other plants.* * * § He states that Persian berries yield, when treatedwith ether a yellow colouring matter, which, on being purified, first by theevaporation of the ether, next precipitated by water, then taken up by alcohol,and slow evaporation of this solution after addition of water, yields a substanceexhibiting all the characters as well as the composition of quercetin.

Schutzenberger and Berlechi state in reference to this assertion of Bolley,that a full investigation of rhamnetin, obtained by the splitting up by meansof sulphuric acid of the rhamnin (the coloured glucoside of the Persianberries), has proved that rhamnetin, however much resembling quercetin,cannot be confounded therewith, and the question therefore is, whether thesubstance taken for quercetin by Dr. Bolley is not in reality rhamnetin.

Rochleder and Hlasiwetz have extracted quercetin from the flower-buds ofthe Capparis spinosa, and Stein has found it in the immature flower-buds ofthe Sophora japonica. Rochleder has proved the existence of quercetin inthe bloom and ripe fruits of the horse-chestnut (JEsculus hippocastanum ).fThe yellow pigment found by Dr. E. Schunck in the leaves and stems of thebuckwheet plant (Polygonum fagopyrtim), is identical with rutin. Accordingto Bolley and Mylius, the yellow pigments of fustic ought to be considered asquercetin.J Hlasiwetz thinks that thuyin of Kawalier|| does not differ fromquercitrin, while the meletin obtained by Stein by spliting up melin alsoappears to be quercetin. The robinin obtained by Zwenger and Droukefrom acacia flowers (Robinia pseudo-acacia) differs from quercetrin, but maybe like that substance split up into sugar and quercetin.§ Robinin is alsofound in the flowers of the Carvus mascula.% These instances are quotedhere to prove the wide distribution of quercetin and its glucosides throughoutthe vegetable kingdom. When pure, quercetin is a lemon-yellow, crystallinepowder, of a far richer shade than quercitrin. It is tasteless and colourless,insoluble in cold, and nearly so in boiling, water, and it is thereby distinguishedfrom rhamnetin, which deposits from a litre of its boiling solution a weightof 0-653 g rm * on cooling, while the quantity of quercetin so deposited isquite insignificant. Quercetin is very soluble in alcohol, and cannot bereadily obtained from such a solution in a crystalline state, except by theaddition of water.

Quercetin is readily dissolved by boiling acetic acid and solutions of alkalies,the liquor in the latter case having an orange-yellow tint; acids precipitate

* “ Annalen der Chemie und Pharmacie,” cxv., 54.

+ “ Chemisches Centralblatt,” new series, iv., 162. “ Comptes Rendus de PAcademie de

Vienne,” xxxiii., 365.

J Schweitzerische, “ Polytechnische Zeitschrift,” ix., p. 22.

il “ Comptes Rendus de PAcademie de Vienne,” xxix., p. 10.

§ “ Ann. der Chem. und Pharmacie,” supplementary vol. i., 257.

51 “ Journal fur Prakt. Chem.” Ixxxviii., 280.