1903.] Group of Yelloiv Colouring Matters. 171" 



without change in position and a fourth more refrangible one being 

 formed, but with Chrysophyll, it is not so pronounced, the solution 

 assumes a greenish tinge and in a short time becomes colourless. The 

 action of HjS0 4 , H^O 2 and nascent H appears to be the same, but the 

 action is slower. HC1 has a very feeble action, the solution gradually 

 becoming paler in colour without any green tinge, and colourless in a" 

 week or two, the three bands gradually fading without the formation of 

 any additional ones. Alkalies have no effect upon the spectrum. 



The means whereby the yellow colouring matters accompanying 

 chlorophyll in the alcoholic green-leaf extracts can be separated from 

 the latter, and their subsequent separation by carbon-bisulphide has 

 been the subject of a previous investigation.* In the light of the 

 results obtained with the flowers it appears now that besides chryso- 

 phyll the other xanthophylls present are the L. and B. and the 

 colouring matter formed from the latter by the action of acid, and iri 

 addition there are present those yellow colouring matters that cause 

 obscuration in the violet and ultra-violet, and as in flowers vary in 

 amount with the particular plant. In those cases where a fourth band 

 is visible in the spectrum this is due to the acid derivative of B: 

 xanthophyll, the proportion of these two colouring matters varying in 

 different leaves, and the preponderance of one or the other can be 

 decided by the aspect of the spectrum and the action of acid thereon. 

 In the above investigation I considered that the interpretation of the 

 series of spectra obtained by the carbon-bisulphide separation was that 

 the crude xanthoph}dl extract is a mixture of chrysophyll and what 

 now turns out to be B. xanthophyll and its acid derivative, but in the 

 light of the experiments upon flowers, and further experiments upon 

 the xanthophyll of the leaf taken in comparison, I am of the belief 

 that L. xanthophyll mus-t also be present in order to fully satisfy the 

 spectroscopic observations. The xanthophyll of all leaves appears to be 

 composed of these same components, and where the flower xanthophyll 

 varies, as in the daffodil, wallflower, charlock and tulip, yet their 

 leaf xanthophyll is the same as in other green leaves. 



An experiment was made with the yellow pigment of the etiolated 

 leaf of the daffodil compared to the normal green leaf of the same 

 plant, and the xanthophyll in each was found to be the same, save that 

 from the etiolated leaf no chrysophyll crystals were obtained, which 

 were plentiful in the extract from the normal leaf in which the chloro- 

 phyll had formed t*fter the etiolated plant had been subjected to the 

 action of sunlight. Lastly, as regards the xanthophyll of the autumnal 

 leaf spectroscopic observation shows the presence of L. xanthophyll,. 

 and a great preponderance of the acid derivative of B. xanthophyll 

 over the normal B. xanthophyll, which causes the spectrum to be four- 

 banded in the majority of cases, the chlorophyll no longer being 

 * ' Boy. Soc. Proc.,' yol. 68, p. 474. 



