264 



Dr. A. E. Everest. 



dissolved in slightly warm acidified (HCl) ethyl alcohol, the solution filtered, 

 and the anthocyan reprecipitated by the addition of 2| times its volume of 

 ether. The liquors were decanted, filtered through a double filter, and 

 treated exactly as before to show the presence of myricetin. 



When the washed and filtered ether solution obtained in this case — the 

 final filtration of the washed ether extract, before testing for the colour 

 reaction, was always included as a precaution against the possibility that a 

 green colour may be formed as the result of some small amount of suspended 

 matter being present — was shaken with dilute aqueous sodium carbonate 

 solution, a splendid clear deep green' was obtained that passed through the 

 colour changes described above. In view of the fact that, as prepared in 

 this case, the ether solution contained no waxes, and A. G. Perkin has 

 pointed out that the colour reactions described above can only be taken as a 

 conclusive test for the presence of myricetin (or less probably gossypetin) if 

 it is quite certain that it is an ether-soluble substance that produces them, 

 despite the fact that the precautions taken above appear to preclude the 

 presence of any ether-insoluble product when the tests were made, a bulk of 

 the ether solution prepared as in the last case was evaporated to di'yness, 

 whereby a yellow residue was obtained which also dissolved in dilute alkalis 

 to give the colour reactions already described — green passing through bluer- 

 green to brown-green, then orange-yellow. As a further precaution, some of 

 the yellow residue was extracted with fresh ether, the ether extract filtered 

 through double filter paper, and half the filtrate shaken with dilute sodium 

 carbonate solution, when a fine green aqueous layer was obtained which 

 passed through the same colour changes ; the other half of the ether extract 

 was evaporated, and the residue treated with dilute sodium carbonate solu- 

 tion, when it also produced the same colour reaction. Furthermore, the 

 residue obtained from the bulk of ether solution originally evaporated when 

 dissolved in acid ethyl alcohol and treated with Mg gave a clear, strong, red 

 coloration. 



These observations leave one possibility to be removed, viz., that the green 

 coloration results from some product of decomposition of the anthocyan 

 pigment during the hydrolysis, or from some unexplained retention of the 

 anthocyan pigment, in colourless form, by the ether. This possibility was 

 removed by taking O'l grm. of the pure crystalline anthocyanin chloride 

 (violanin chloride) — a quantity greatly in excess of that present in the ether- 

 alcohol liquors — dissolving it in alcohol, concentrating the solution under the 

 conditions used for the extracts above mentioned, hydrolysing with boiling 

 acid, then extracting the cooled product with ether, washing the ether 

 extract, finally filtering the washed ether layer, all under exactly the same 



