180 Mr. C. A. Schunck. The Yellotu Colouring Matters 



debated point whether the absorption bands in the violet and ultra- 

 violet region shown by crude chlorophyll solutions are due to chlo- 

 rophyll itself or to the accompanying yellow colouring matters. 



The chlorophyll solutions experimented upon were obtained in the 

 usual manner by extracting the colouring matter from the leaves with 

 boiling alcohol. I have already shown* that chlorophyll solutions pre- 

 pared in this way show three characteristic absorption bands on proper 

 dilution, in the violet region of the spectrum, giving in the less 

 refrangible region the well-known spectrum of four bands which in 

 very pure solutions may be said to be reduced to three, so faint does 

 the fourth band appear. 



If the extracts are concentrated enough one finds invariably on 

 standing for a day or so minute sparkling red crystals deposited on 

 the sides of the containing vessel or along with the fatty deposit, 

 coloured green by chlorophyll, which generally comes out of the extracts 

 on standing. These crystals are found in variable quantities, but 

 more often than not in a minute quantity. 



This is the first yellow colouring matter one comes across and is the 

 erythrophyll of Bougarel, and the chrysophyll of Hartsen and 

 Schunck. f That chrysophyll is always to be found in chlorophyll 

 solutions proves that either it pre-exists as such along with chloro- 

 phyll in its alcoholic extracts, or that it is formed spontaneously 

 from one of the colouring matters, and is not, according to Hansen,:}; 

 formed under certain conditions only by the decomposition of a deri- 

 vative. Chrysophyll thus obtained is not a very stable substance, and 

 in order to preserve it unchanged it should be placed in a glass tube 

 through which a current of hydrogen has been passed before sealing, 

 and kept in the dark. Its alcoholic solutions are bleached rapidly 

 when exposed to the air and sunlight, and even when kept in the 

 dark a change very soon takes place in its solutions as shown by its 

 spectrum, though there is no apparent change in colour. According 

 to Arnaud§ it is identical with carotin. Chrysophyll gives no absorp- 

 tion bands in the red, yellow, or green, but three very distinctive 

 bands in the violet region of the spectrum which, as I have shown, j| 

 are almost identical in position with those of carotin. They (Plate 6, 

 fig 5) occupy intermediate positions compared to the three bands 

 shown by crude chlorophyll solutions in the same region, being shifted 

 more towards the red end of the spectrum. 



The method I have applied for separating the other accompanying 

 yellow colouring matters from the chlorophyll is that of treating the 



* ' Roy. Soc. Proc.,' vol. 63, p. 393. 



f ' Roy. Soc. Proc.,' rol. 4-4, p. 449. 



% ' Die Farbstoffe des Chlorophylls.' 1889, p. 58. 



§ ' Compt. Rend.,' vol. 102, p. 1119, and vol. 104, p. 1293. 



|| 1 Roy. Soc. Proc.,' vol. 63, p. 393. 



