THE CHEMISTRY OF CHLOROPHYLL 429 



and light petroleum, but soluble in alcohol, ether, chloroform, 

 benzene, aniline, and carbon disulphide. It readily formed 

 double salts when treated with the acetates of heavy metals ; 

 the copper derivative, which was beautifully crystalline, had a 

 composition corresponding with the formula C 68 H 71 Oi 7 N 5 Cu 2 . 



The phylloxanthin was prepared from the ethereal solution 

 after separation of the phyllocyanin by acid, by allowing it to 

 evaporate in flat basins. The residue was dissolved in chloro- 

 form and to the solution thus obtained, several times the bulk 

 of alcohol was added. A precipitate containing the greater part 

 of the phylloxanthin was thereby obtained. This was dissolved 

 in hot glacial acetic acid, from which it is deposited on cooling. 

 The product thus obtained was subjected to a somewhat com- 

 plicated purification process, but in spite of this it could not 

 be obtained pure and free from fatty admixtures. It was a 

 dark green mass without crystalline structure, soluble in hot, 

 and but slightly soluble in cold alcohol, and soluble in most 

 organic solvents. Its absorption spectrum was similar to that 

 of phyllocyanin. By the action of strong acids in the cold it 

 can be converted into this substance. 



Alkachlorophyll. — The action of alkalis was also the subject of 

 investigation by Schunck (afterwards with Marchlewski). 



Senebier had noticed that the action of alkalis on chlorophyll 

 solution produced no marked change in the colour, and 

 Berzelius adopted the view that no chemical change was 

 produced by the treatment. Hansen, who made a detailed 

 study of the subject, expressed the opinion that, by the action 

 of alkalis, a saponification took place, with the elimination of a 

 fatty acid which was in combination with the pigment. By 

 this treatment, according to his opinion, " pure chlorophyll " was 

 obtained. 



Schunck, and afterwards Schunck and Marchlewski, pre- 

 pared by the action of alkalis a product which was called 

 alkachlorophyll, and which, they concluded, was not the original 

 green pigment, but a derivative of the same. They prepared an 

 alcoholic extract of chlorophyll, to which, after standing for some 

 hours to allow the separation of fats and resins, they added 

 sodium hydroxide. The mixture thus obtained was boiled for 

 some hours. It was then allowed to stand, filtered from the 

 resinous material, and then treated with carbon dioxide. A 

 precipitate was obtained containing the sodium salt of alka- 



