BY JAMES M. PETBIE. 339 



The lead ■ acetate precipitate. — The concentrated solution was shaken out 

 with ether 10 times. This ethereal solution was a deep yellow colour and was 

 next agitated with (a) ammonium carbonate, and (b) sodium carbonate. 



(fl). The ammonium carbonate extract was acidulated with sulphuric acid, 

 shaken out with etlier, and the solvent distilled. A bulf-coloured crystalline re- 

 sidue was obtained, which was difficult to purity. This substance was soluble in 

 water, alcohol, ether, chloroform, acetone and ethyl acetate, but these solvents 

 dissolved both crystals and impurity togetlier, and recrystallisation did not im- 

 prove the appearance of the crystals. The acjueous solution was next digested 

 with animal charcoal, and filtered. During the filtration the colourless solution 

 became purple, the first washing with water yielded a hlue solution, and the 

 second washing became green. 



The crystals which were obtained after this treatment were still impure. 

 The aqueous solution was acid to litmus and possessed a hot peppery taste. It 

 gave a negative reaction with Molisch's test. The crystals wei'e lath-shaped 

 with pointed ends and occurred in groups of rosettes. After drying at 100° C, 

 the melting point was tested, when it was found that at 172° C. some change 

 took jdace, resulting in the formation of a white sublimate in the tube, and a 

 white tilm round each crystal. About 21G°C. the substance melted and charred. 



The neutralisation equivalent was obtained by titrating 14 milligrams of the 

 crj'stals with 6.5 c.c. of centinormal soda, which gave 216 as the molecular weight 

 of the acid. The amount of material was too small for further investigation. 



{h). The sodium carbonate extract also exhibited the brilliant colours. For 

 example, the first addition gave a briglit violet (permanganate) colour to the 

 alkaline solution, the second addition yielded a deep green colour which rapidly 

 i-hanged to cherry-red. Acidulated with sulphuric or hydrochloric acid the solu- 

 tion wa-s yellow, and when reshaken with ether the ethereal solution also was a 

 bright yellojc colour. When filtered (lie latter solution became red and violet by 

 oxidation. On evaporation the ether left a red solid. This substance was .soluble 

 in dilute ammonia forming a deep reddish-violet colour, gradually becoming 

 brown on standing. This, on acidulating with sulphuric acid, gave an intense 

 yellow colour. 



The lead acetate filtrate. — This was shaken out wath ether many times, and 

 the ethereal sdlution after concentration was agitated successively with am- 

 monium carbonate, sodium carbonate, and caustic soda. These solutions when 

 acidified with sulphuric acid and agitated with ether, after distillation left a 

 small oily residue of a dark brown colour. 



Luteolin, and other colour substances. — These vaiious alkaline liquids with 

 the many different colours ranging from yellow, green, blu€, to violet and red all 

 gradually changed to a uniform brownish-red colour on standing for some time, 

 and the acidulated solutions gave }>riiivn precipitates. 



Certain of the above remarkable colour changes, and the reactions described, 

 correspond to those obtained for the yellow dye luteolin by Power and Salway 

 (19) in their investigation of Erythrophloeum guineense. These authors ob- 

 tained a very small amount of luteolin from a large quantity of the plant, and 

 they showed that it existed in the plant as a glucoside. 



Conspicuous evidence of the presence of other powerful colouring matters 

 ■was shown, but the amount obtained was not sufficient for further examination. 



The aqueous solution remaining from the lead acetate filtrate after agitating 

 "with ether, contained much sugar. 



