1884.] Mr. E. Schunck. On the Constitution 'of Chlorophyll. 285 



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II. " Supplementary Note on the Constitution of Chlorophyll." 

 By Edward Schunck, F.R.S. Received February 6, 1884. 



After the reading of the note on chlorophyll at the meeting of the 

 Society on December 13th, I was reminded by Professor Stokes that 

 he and others had succeeded in separating the complex to which the 

 term chlorophyll had previously been applied into two substances, or 

 rather groups of substances, one characterised by its green colour and 

 red fluorescence, the other showing a more distinctly yellow colour 

 without fluorescence, and he suggested to me that it would be advis- 

 able to ascertain whether the property of yielding glucose by decom- 

 position with acids might not belong to one of these substances or 

 groups of substances only. Professor Stokes at the same time kindly 

 communicated to me the details of the process whereby he succeeded 

 in effecting the separation referred to, a process depending on the 

 action of carbon disulphide in removing some of the bodies contained 

 in an alcoholic solution of crude chlorophyll in preference to others. 

 The process employed for the same purpose by Mr. Sorby is essentially 

 the same. 



Before applying disulphide of carbon to an alcoholic extract of green 

 leaves according to the process of Professor Stokes, it was necessary 

 first to remove the ready-formed glucose, tannin, and other matters 

 soluble in water, which almost always exist in such extracts, and 

 which would by their presence have rendered the result of the experi- 

 ment quite uncertain. This was done in the way I have already 

 described. An ethereal solution of chlorophyll prepared by my 

 method was evaporated, and the residue having been dissolved in 

 alcohol, the solution was mixed with a quantity of carbon disulphide 

 larger than the alcohol would dissolve, and the mixture well shaken. 

 The carbon disulphide acquired a dark green colour, while the super- 

 natant alcoholic liquid, containing principally the xanthophyll of 

 Professor Stokes and Mr. Sorby, was yellow with a tinge of green. 

 The two liquids having been separated, the lower dark green one was 

 washed several times with alcohol to remove any of the xanthophyll 

 that might still be present, and having then been mixed with a large 

 quantity of alcohol, a current of air was passed through it to remove 

 the excess of carbon disulphide as directed by Professor Stokes. In 

 this way I obtained two liquids, one intensely green, the other deep 

 yellow with only a tinge of green. The two liquids were found to 

 contain substances essentially different so far as regards their 

 products of decomposition with acids. The yellow liquid having 

 been mixed with dilute sulphuric acid was evaporated in the water- 

 bath, water being added during evaporation, until the liquid had lost 

 nearly all its colour. A quantity of yellow fatty matter separated 



