accompanying Chlorophyll and their Spectroscopic Relations. 470 



and the fourth to intensify in the crude solution, together with its 

 effect upon the alcoholic portion and chrysophyll, is in accordance with 

 the view that it is a mixture of the two. I also think the action of 

 acid upon the spectrum of the alcoholic portion explains the origin of 

 the fourth band in the crude solution and its appearance in the later 

 CS 2 fractions, and conclude that it is due to the colouring matter 

 giving the changed spectrum, and formed from the alcoholic portion, 

 either spontaneously or by the action of the acid juices during or after 

 extraction, and that its variability in intensity depends upon the 

 amount of this colouring matter formed. If there be but little acid 

 present, or if means be taken to neutralise it during extraction, then 

 the band will appear, but faint, and in some cases perhaps absent. 

 The green colour assumed by the crude solution is no doubt due to 

 the formation of the peacock-blue colouring matter, which, mixed with 

 the yellow chrysophyll, causes the solution to appear green. 



From the above experiments I was evidently in the wrong in the 

 former investigation in considering that the four-banded spectrum 

 exhibited by the crude solution of the xanthophylls represented a single 

 colouring matter, to which I restricted the name Xanthophyll, and think 

 n6w the right interpretation is that this spectrum is due to a mixture of 

 colouring matters, the chief constituent of which I have been led to 

 believe from the above facts is Chrysophyll, the only member so far of 

 the accompanying yellow colouring matters, I believe, that is obtainable 

 in a crystalline form. 



EXPLANATION OF PLATES. 

 (The solvent in every case is Alcohol.) 

 Plate. 5. 



Xanthophylls obtained from an extract of Ficus Eepens in the month of 

 February : — 



A. (1) The first CS 2 fraction. 



(2) The thirteenth and final fraction. 



(3) The alcoholic portion, showing in this experiment four distinct bai ds. 



(4) The above + HC1, in this experiment showing a distinct fourth band. 



B. Some of the CS 2 fractions in alcohol : — 



(1) The first ; (2) the second ; (3) the fifth ; (4) the seventh ; (5) the 

 ninth. 



C. (1) The first CS 2 fraction. 



(2) The crude solution of the xanthophylls. 



(3) A mixture of the first CS 2 fraction and the alcoholic portion. 



(4) The alcoholic portion. 



D. Comparison of — 



(1) The first CS 2 fraction. 



(2) Chrysophyll. 



(3) The crude solution of the xanthophylls in which the fourth band in 



this instance is faint. 

 VOL LXVIII. 2 M 



