accompanying Chlorophyll, and their Spectroscopic Relations. 185 



the three bands in the violet region, is I think a proof in itself that 

 they are clue to the same colouring matter that produces the character- 

 istic and unmistakable spectrum in the less refrangible region, or to a 

 very intimately connected colouring matter so far unknown. Seeing 

 also that all the chlorophyll derivatives give a characteristic absorption 

 in the violet and ultra-violet region, it would be strange that 

 chlorophyll proper should prove the exception, and it is an interesting 

 fact that its two chief, and intimately connected decomposition pro- 

 ducts inter se — phyllocyanin and phylloxanthin — should have, as I 

 have shown,* bands in the violet region in identical positions with 

 these three chlorophyll bands, the first of them corresponding to a 

 faint, but distinct one, observable in pure phyllocyanin solutions on 

 proper dilution, the other two to the two characteristic phylloxanthin 

 bands in the violet region. 



Summary. 



1. I find in all crude alcoholic extracts of healthy green leaves, two 

 yellow colouring matters accompanying the chlorophyll. One chryso- 

 phyll which deposits out of the extracts on standing in lustrous red 

 crystals, but more often than not in minute quantities, the other 

 obtained by treating the extracts with animal charcoal in the cold, the 

 charcoal taking up the chlorophyll, and leaving a yellow solution 

 which deposits on spontaneous evaporation an amorphous substance 

 impregnated with much fatty matter, and to which I have restricted 

 the name xanthophyll. Another yellow colouring matter is sometimes 

 found along with xanthophyll which gives no absorption bands, but 

 only an obscuration in the violet and ultra-violet region of the 

 spectrum, and in such cases a separation can be effected by ether. 

 There is also evidence to show that other yellow colouring matters 

 may exist. Xanthophyll, however, I believe, is the predominating 

 yellow colouring matter accompanying chlorophyll in the healthy 

 green leaf, and I also find it to be identical with the principal yellow 

 colouring matter of the faded autumnal leaves. 



2. Chrysophyll and xanthophyll each give a characteristic absorp- 

 tion spectrum in the violet and ultra-violet region • the former consists 

 of three bands, the latter of four, but in slightly different positions. 

 Crude chlorophyll solutions also give, in addition to the characteristic 

 spectrum of four bands in the less refrangible region ; three characteristic 

 bands in the violet, and from observations by means of photography 

 I come to the conclusion that these bands are due to chlorophyll 

 itself, and not to any of the accompanying yellow colouring matters 

 which the majority of former observers believed they were due to. I 

 also find that phyllocyanin and phylloxanthin have bands in identical 

 positions with these three chlorophyll bands. 



* ( Eoy. Soc. Proc.,' vol. 63, p. 393. 



