188 



diluted acids into a brown-red, hard resin (ratanhia-red n 

 Ci2 He O3, also existing ready formed in the root), and into a 

 sweet body which reduces the solution of copper. 



[Ratanliill=C2o His NOo (Peckolt's Angelin). Contained in 

 the Ameiican Ratanhia extract (according to Ruge), and in the 

 resin of Hillia spectabilis. In order to prepare it from the last- 

 named substance, the pulverised resin is repeatedly digested with 

 water, the residue dissolved in water and hydrochloric acid and 

 evapoi'ated v^-itli a gentle heat to form crystals. The crystals are 

 freed from the mother-ley by pressing, again dissolved in acid 

 water and recrystallised. After repeating this process six or seven 

 . times, a white crystalline mass is ol^tained, which is dissolved in 

 boiling distilled Avater and set aside to crystallise. — -The Ratanhin, 

 ]:)iirified in this way, presents delicate, flexible needles, of a pure 

 white colour and a vivid satin lustre. It is nearly insoluble in 

 cold, and only s])aringly soluble in boiling water ; it is still less 

 soluble in alcohol, both cold and boiling, and almost insoluble in 

 ether. It is tasteless, without odour, and of neutral reaction. R. 

 dissolves in acid and in alkaline liquids, but is thrown down again 

 on neutralising the solution. It is likewise precipitated by alcohol, 

 alcohol-ether, and in acid sohitions by })hosphomolybdic acid and 

 by Nessler's reagent, not by chloride of platinum. Heated above 

 150° it melts and volatilises in a higher temperature, while 

 emitting a not unpleasant aromatic odour. Quickly heated, it 

 becomes carbonised with a horny odour and under formation of 

 inflammable gases. Ratanhin, when formed into a thin pul]) with 

 water and an adequate quantity of dilute nitric acid, and boiled 

 for some time, becomes first of a rose coloui*, and then changes 

 from blood-red to violet and blue, while exhibiting a splendid 

 red fluorescence.] 



Red Pi«'Ilieilt of Berries is mostly anthocyan, reddened by 

 acids; yet there are some exceptions. For instance, the red of 

 strawberries behaves like cissotannic acid, likewise, the red pig- 

 ment of the berries of Ligustrum vulgare behaves difierently and 

 is named ligulin. 



Ked Pigment of Flowers is mostly anthocyan, reddened by 

 acids. 



[Iteg'iilinil, found by T. L. Phi|)son in the green pericarp of the 

 walnut (Juglans regia). Crystallises in yellow, protracted 

 octahedra or needles, little soluble in water, better in alcohol and 

 benzol; becomes after a few hours transformed into black, amor- 

 phous Regianic acid; forms with alkalies soluble salts of a splendid 

 purple coloui', with oxyd of lead an insoluble, bi-OMTi-violet salt. 

 On boiling the aqueous or alcoholic solutions of R. with hydi'o- 

 chloi'ic acid, Regianic acid separates as a dense, black precipitate.] 



