CH. v] ISOLATION AND CONSTITUTION OF ANTHOCYANINS 59 



Morot (122), 1849. The flower-pigment of Centaurea Cyanus. 

 The pigment was prepared by pouring a water extract of the flowers 

 into alcohol. The blue flakes of the precipitate, when collected and dried, 

 formed a blue powder, which, on analysis, gave the following results : 



(iv) 37-03 % 5-26 % 57-71 % 



Glenard (129, 130), 1858. The colouring matter of wine. 



The pigment was prepared by first adding lead acetate to wine. 

 The blue precipitate of the lead salt was then treated with ether con- 

 taining hydrochloric acid gas, which set free the pigment. The latter 

 was then extracted with rectified spirit, the solution evaporated, and 

 water added which precipitated the pigment in red flakes, since it is 

 scarcely soluble in water, The product was not crystalline ; on analysis 

 the results were : 



C H 



From anthocyanin ... 57-02% 4-89% 37-89% 

 Calculated for C 2 HO ... 57-1% 4-8% 38-1% 



The pure lead salt was also prepared by adding lead acetate to 

 a dilute alcoholic solution of the pigment. The product, washed and 



dried at 120, gave: 



C H O 



Lead salt of pigment ... 59-67 % 4-49 % 35-84 % 

 Calculated for C 20 H 9 9 ... 59-71% 4-47% 35-82% 

 Hence Glenard gave to the pigment, which he termed oenoline, 

 the formula C 20 H 9 9 . OH, and to its salt, the formula C 20 H 8 9 . PbO. 



Church (147), 1877. Pigment from the leaves of Coleus. 

 The pigment was extracted with cold alcohol acidified with sulphuric 

 acid ; the acid was then precipitated with baryta, and the solution 

 concentrated. The product was further purified by extraction with 

 alcohol and precipitation of the alcohol solution with ether or water. 

 Church termed the pigment cole'in and gave it the composition C 10 H 10 5 ; 

 its lead salt he expressed as C 20 H 18 Pb0 10 . 



Senier (148), 1877. The flower-pigment of Eosa gallica. 

 The dried petals were first digested with ether, and the pigment 

 then extracted with alcohol and precipitated with lead acetate. The 



