478 Mr. C. A. Schunck. The Yellow Colouring Matters 



the various fractions contain these same colouring matters in different 

 proportions, depending upon their relative solubility in CS 2 and alcohol, 

 which is borne out by the slight differences in their spectra, as we pass 

 in rotation from the first to the last fraction. Chrysophyll, as is well 

 known, is always found deposited in the from of sparkling red crystals 

 from the crude chlorophyll extracts when concentrated sufficiently on 

 standing, but in one case only have I been able to obtain the crystals 

 from a crude solution of the xanthophylls after removing the chloro- 

 phyll, though I have made many attempts. The failure in this respect 

 may perhaps be accounted for by the very great difficulty there always 

 is in even re-crystallising this substance. 



That the bands are not quite in identical positions is admissible, for 

 one cannot obtain a complete separation by a method that depends 

 upon the relative solubility of its constituents in two solvents, so that 

 we should expect to find in the first fractions a little of the other 

 colouring matters (which tend to produce the shifting of the bands), 

 together with the greater portion of the chrysophyll. 



From the above results it is, I think, evident that chrysophyll pre- 

 exists, and is not formed spontaneously from one of the colouring 

 matters of the leaf as has been held by some observers, and that it is 

 one if not the chief constituent of the xanthophyll group of yellow 

 colouring matters, accompanying chlorophyll in the healthy green leaf. 

 Chrysophyll evidently corresponds to the orange xanthophyll of 

 Sorby,* which he states is one of the most universally distributed of 

 all vegetable colouring matters, occurring in greater or less quantity in 

 all classes of plants, including fungi. 



The action of acid upon the spectrum of chrysophyll, the first CS 2 

 fractions, the alcoholic portion and the crude solution of the xantho- 

 phylls is instructive when compared together, and tends further to 

 confirm the above view taken of the constitution of the crude solution. 

 If a small quantity of HC1 be added to each, the effect upon the 

 chrysophyll spectrum and that of the first CSo fractions is to cause 

 the bands to fade and the solutions to become gradually colourless 

 (Plate 6, G, 1 and 2). In the crude solution the effect is to cause the 

 first band to become fainter and the fourth darker, even though it be 

 extremely faint, as I have pointed out is the case in some crude 

 solutions. The bands then after a short time fade, but the solution 

 assumes a green colour before becoming colourless (Plate 6, G, 3 and 4). 



Lastly, in the alcoholic portion, as before stated, the effect of the acid 

 is to remove the first band, and to clear up the spectrum, the three 

 remaining bands becoming intensified, especially the third and fourth. 

 The bands then fade and the solution assumes a peacock-blue colour, 

 which also after a short time fades, leaving the solution colourless 

 (Plate 6, G, 5). Thus the effect of acid in causing the first band to fade 



* ' Roy. Soc. Proc.,' vol. 21, p. 457. 



