344 MISSOURI AGRICULTURAL EXP. STA._, RESEARCH BULLETIN NO. IO 



"4. If an alcoholic solution of xanthophylls is mixed with carbon 

 bisulphide and the solvents separated with water, the xanthophylls will 

 be distributed between both layers." 



Schunck, 1 using Sorby's method, showed that if alcoholic solu- 

 tions of xanthophylls are repeatedly shaken with carbon bisulphide 

 all the xanthophylls with spectroscopic absorption properties can be 

 extracted. 



Tswett 2 studying this question again in 1911 states that, "Accord- 

 ing to a well known rule, organic compounds are best soluble in solv- 

 ents of similar composition," and concludes that carotin, a hydrocarbon, 

 is therefore much more readily soluble in the hydrocarbons of the 

 aliphatic and cyclic group than in alcohols, a point well illustrated 

 by the above experiments of Willstatter and Mieg. Continuing, Tswett 

 states, "If one therefore shakes an eighty to ninety per cent alcoholic 

 solution of carotin with petroleum ether, the pigment goes almost 

 completely into the petroleum ether layer." "A pigment which in 

 the above mentioned two phase system occupies the lower alcoholic 

 layer, is therefore not a carotin." It may be added in the light of 

 Willstatter and Mieg's investigation that if the original solution before 

 differentiation was a mixture of carotin and xanthophylls, the lower 

 alcoholic layer will contain the xanthophylls. 



ADSORPTION PROPERTIES OF CAROTIN AND XANTHOPHYLLS. 



Considering now the so-called adsorption properties of the pig- 

 ments, we find that this striking characteristic was discovered and 

 elaborated by Tswett. 3 This investigator found that by shaking a 

 perfectly anhydrous petroleum ether or carbon bisulphide solution of 

 the mixed pigments of green plants with an excess of dry calcium 

 carbonate, Inulin or Saccharose, all the pigments will be completely 

 adsorbed by the material with the exception of the carotin, which can 

 be readily washed out of the material with the free solvent. In the 

 case of petroleum ether solutions the green colored mass can now 

 be completely freed from all its pigments by means of petroleum ether 

 containing ten per cent absolute alcohol. If the resulting solution 

 is now shaken with eighty per cent alcohol the petroleum ether layer 

 will contain the chlorophyll pigments and the alcohol layer the xan- 

 thophylls. "If to the petroleum ether solution of the mixed pigments 



1. Proc. Roy. 72 (1903). 



2. Ber. der. Deut. Botan. Gessel. 29, p. 630 (1911). 



3. Ber. der. Deut. Botan. Gessel. 24, p. 316 and 384 (1906). 



