The Production of Anthocyanins and Anthocyanidins. 261 



It would appear, therefore, that the colour reactions of anthocyans described 

 by Willstatter and his collaborators as due to alum* are dne to the presence 

 of iron in their reagent, and not to the action of pure alum. 



Hydrolysis of the Anthocyanin ( Violanin) Chloride. 



As the hydrolysis of the anthocyanin chloride had 7iot been carried out 

 prior to the appearance of Willstatter and Weil's paper on the blue-black 

 Pansy, the method described by them for the hydrolysis of violanin chloride 

 was adopted. 



By carrying out the hydrolysis quantitatively, the author found that 

 0*4730 grm. of his anthocyanin chloride (violanin chloride), dried as 

 described above, yielded 0'2205 grm. of anthocyanidin chloride (delphinidin 

 chloride), dried at 100° C. ; this included the small quantity recovered from 

 the filtrate by means of amyl alcohol, i.e. the anthocyanidin chloride 

 = 46"61 per cent, of the weight of dry anthocyanin chloride taken. 

 Willstatter and Weil found, for violanin chloride, a yield of 44 and 43 per 

 per cent, (two experiments) of delphinidin chloride — they did not recover 

 the small portion of pigment present in the filtrate — and state that theory 

 requires 53'85 per cent, if violanin chloride is C27H29O15CI, whereas if it is 

 CavHsiOieCl, it should yield 52-37 per cent. The exact formula is still 

 uncertain (cf. Willstatter and Weil, loc. cit.). 



The anthocyanidin chloride obtained by the author separated in minute 

 micro-crystalline aggregates, not in the well-defined crystals obtained in the 

 case of cyanidin chloride. 



For identification purposes, the author's hydrolysis product was tested in 

 respect of the following characteristics, viz., solubility in methyl alcohol, in 

 ethyl alcohol, in water, in dilute sulphuric acid, and in hydrochloric acid 

 (various concentrations); extraction from aqueous solution by ether, and 

 removal of trace of pigment extracted by shaking with dilute acid ; ferric 

 chloride reaction, in aqueous solution, in alcoholic solution, and the effect of 

 dilution with water in the latter case upon the coloration produced ; the 

 colour change produced when sodium carbonate is added to an acid solution ; 

 and, finally, the effect of heat upon the dry product. In every case it was 

 found that the results obtained exactly coincided with those obtained by 

 Willstatter and Weil {loc. cit.) or Willstatter and Miegf for delphinidin 

 chloride. The deposition of the violet colour base from the solution in 

 water first formed by the chloride, and the absence of such deposition when 



* E.g., cf. ' Annalen,' vol. 408, pp. 35, 38, 50, 130, 133, 141 (1915). 

 t ' Annalen,' vol. 408, p. 61 (1915). 



