196 LEGUMINOSiE. 



fragments rarely larger than a pea, easily splitting into still smaller 

 pieces, whicli are seen to be perfectly transparent, of a bright garnet 

 hue, and amorphous under the microscope. In cold water they sink, but 

 partially dissolve by agitation, forming a solution of very astringent taste, 

 and a pale flocky residue. The latter is taken up when the Uqiiid is 

 made to boil, and deposited on cooling in a more voluminous form. 

 Kino dissolves almost entirely in spirit of wine ("SSS), alFordinff a 

 dark reddish solution, acid to litmus paper, which by long keeping 

 sometimes assumes a gelatinous condition. It is readily soluble in 

 solution of caustic alkali, and to a large extent in a saturated solution 

 of sugar. 



Chemical Composition— Cold water forms with kino a reddlsli 

 solution, which is at first not altered if a fragment of ferrous sulphate is 



added. But a violet colour is produced as soon as the liquid is cautiously 

 neutralized. This can be done by diluting it with common water (con- 

 taining bicarbonate of calcium) or by adding a drop of solution of acetate 

 of potassium. Yet the fact of kino developing an intense violet colour 

 in presence of a protosalt of iron, may most evidently be shown by 

 shaking it with water, and iron reduced by hydrogen. The filtered 

 liquid is of a brilliant violet, and may be evaporated at 100° without 

 turning green ; the dried residue even again forms a violet solution with 

 water. By long keeping the violet liquid gelatinizes. It is decolorized 

 by acids, and turns red on addition of an alkali, whether caustic or 

 bicarbonated. Catechu, as well as crystallized catechin, show the 

 same behaviour, but these solutions quickly turn green on exposure 

 to air. 



Solutions of acids, of metallic salts, or of chromates produce copious 

 precipitates in an aqueous solution of kino. Ferric chloride forms a 

 dirty green precipitate, and is at the same time reduced to a ferrous sa ^ 

 Dilute mineral acids or alkalis do not occasion any decided change 

 colour, but the former give rise to light brownish-red precipitates c 

 Kmo-tannic Acid. By boiling for some time an aqueous solution 

 kmno-tanuic acid, a red precipitate. Kino-red, is separated. ^ 



_ Kino in its general behaviour is closely allied to Pegu catechu an^ 

 yields by similar treatment the same products, that is to say, it ano 

 Pijrocatechin when submitted to dry distillation, and Protocatem ^^ 

 Acid together with Fhloroglucin when melted with caustic soaa 



potash. 



iderable 



Yet m catechu the tannic acid is accompanied by a consiciei .^^ 

 amount of catechin, which may be removed directly by exhaustion ^^^ 

 ether. Kino, on the other hand, yields to ether only a minute percen <^^^ 

 of a substance, whose scaly crystals display under the n^i^'^^^^Piij^es * 

 character of Pi/roc«fec/im, rather than that of catechin, which c^Tf ^l .g^ 

 in prisms. The crystals extracted from kino dissolve freely m cold \v „ _' 



red on addition of an alkali. This is the behaviour of catec m> .^ 

 well as of pyrocatechin ; but the difference in solubility ff\^,, 

 favour of the crystals afforded by kino being pyrocatechin rather 



We thought pyrocatechin must also occur in the mother-plant o 



\ 



