196 LEGUMINOSiE. 



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

 pieces, which 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 liquid is 

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

 Kino dissolves almost entirely in spirit of wine ('838), affording 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 reddish 

 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. 3y 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 salt. 

 Dilute mineral acids or alkalis do not occasion any decided change of 

 colour, but the former give rise to liglit brownish-red precipitates of 

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

 kinno-tannic acid, a red precipitate. Kino-red, is separated. 



Kino in its general behaviour is closely allied to Pegu catechu, and 

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

 Fyrocatechin when submitted to dry distillation, and Protocatechuic 

 Acid together with Phloroglucin when melted with caustic soda or 

 potash. 



Yet in catechu the tannic acid is accompanied by a considerable 

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

 ether. Kino, on the other hand, yields to ether only a minute percentage 

 of a substance, whose scaly crystals display under the microscope the 

 character of P?/7'oca^ec/6/7i, rather than that of catechin, which crystallizes 

 in prisms. The crystals extracted from kino dissolve freely in cold water, 

 which is not the case with catechin, and this solution assumes a fine 

 green if a very dilute solution of ferric chloride is added, and turns 

 red on addition of an alkali. This is the behaviour of catechin as 

 well as of pyrocatechin ; but the difference in solubility speaks in 

 favour of the crystals afforded by kino being pyrocatechin rather than 

 catechin. 



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



