172 Mr. C. A. Sclmnck. The Xantliopliyll [Apr. 17, 



formed at this season and disappearing, leaving the accompanying 

 xanthophylls which gives the leaf its characteristic autumnal colour. 



From these few observations it seems that the formation of 

 chrysophyll within the leaf depends on similar conditions to the 

 elaboration of the chlorophyll, but whether it is formed independently 

 or from one of the xanthophylls present is still a problem to be 

 solved. 



Fruit, etc. 



Several varieties of the orange were examined, and here a considerable 

 amount of the pigment of the rind is soluble in water and causes the 

 great amount of obscuration in the violet and ultra-violet observed in 

 the alcoholic extracts of the pigment. The redness of the rind which 

 is present in many (as the Blood, Seville and Tangerine) appears to be 

 due to these colouring matters, which can be removed by boiling water 

 leaving the rind the normal orange colour. By treating the rind with 

 boiling alcohol a rich orange- coloured extract of the pigment is obtained, 

 from which on cooling a deep orange deposit forms. If this deposit be 

 dissolved in a little absolute alcohol chrysophyll crystals form in a small 

 quantity on slow evaporation. The spectrum of the alcoholic solution 

 of the deposit, which as in the deposits from flowers exhibits no 

 obscuration in the violet and ultra-violet, indicates that besides 

 chrysophyll there are also present the acid derivatives of B. and Y. 

 xanthophyll. The mother liquor of the deposit which contains 

 the majority of the pigment spectroscopically does not show the 

 presence of chrysophyll, indicating that this substance is present in but 

 small quantity, the absorption bands visible after the separation 

 by carbon-bisulphide appearing to be due principally to the acid 

 derivatives of B. and Y. xanthophyll. In the lemon the yellow 

 pigment of the rind consists principally of the colouring matters 

 producing obscuration together with the above acid derivatives. 



The crystalline substance obtained from the pigment of the carrot 

 root (Daucus Carota) and which is termed Carotin, has been the subject 

 of investigation by Arnaud,* who considers it a hydrocarbon of the 

 formula C 2 6H 38 , though Husemann who has also examined the substance 

 applies that of Ci 8 H 24 0. I have compared this substance with 

 chrysophyll and find, as with Arnaud, that they have the same proper- 

 ties and that their spectroscopic properties, which he did not examine, 

 are identical save that the bands of carotin appear to be very slightly 

 moved towards the violet as compared to those of chrysophyll 

 (Plate 7, figs. 1 and 2). Towards acids the spectroscopic reaction is 

 identical in each. It may be the slight difference in the positions 

 of the bands is merely due to spontaneous change or oxidation that has 



* ' Compt. Band.,' vol. 100, p. 751 ; vol. 102, pp. 1119, 1319 ; vol. 104, p. 1293 ; 

 Tol. 109, p. 911. 



