CAROTINOIDS IN THE CRYPTOGAMS 97 



by alkalies, and by its color reaction with IK'1. T-\\r!t noticed, like 

 Sorby, that alkali would restore the yellow color of alcoholic solu- 

 tions turned blue with acid, but mentioned that the shade of yellow 

 was not quite the same as the original. Tswett regarded the carotin 

 present as identical with the carotin of higher plants. The xantho- 

 phyll, however, was probably erroneously regarded as a special xan- 

 thophyll, to which Tswett gave the name fucoxanthophyll. Tswett 

 also studied the chlorophyllins of the brown algae, finding chloro- 

 phyllin a (chlorophyll a of Willstatter) and chlorophyllin y, a spe- 

 cial pigment, which he regarded as characteristic of the Phceophycece. 

 This has not been confirmed by Willstatter and Page (1914) who 

 found only chlorophyll a in the brown algae. 



Czapek (1911) submitted petroleum ether extracts of carefully 

 dried Fucoideoe to a Tswett chromatographic analysis and found 

 chlorophyll a, fucoxanthin and xanthophyll, but no carotin. The fail- 

 ure to find carotin was probably due to the fact that Laminaria, 

 according to Willstatter and Page, contain very small quantities of 

 carotin. 



Kylin (1912) has given us one of the best systematic examinations 

 of the carotinoids of the Phaeophyccac. Although Kylin falls into the 

 error of regarding the Molisch microchemical crystallization test, 

 which he performed on a large number of species, as specific for caro- 

 tin, he nevertheless succeeded in isolating the first crystals of this pig- 

 ment from brown algae. Impure crystals of xanthophyll were also 

 secured. An unsuccessful attempt w r as also made to secure crystals 

 of fucoxanthin, for which pigment Kylin prefers the name phycoxan- 

 thin. Kylin pointed out the probable close chemical relation of fuco- 

 xanthin to xanthophylls. He found that a greater solubility in petro- 

 leum ether is one of the distinguishing differences, a result which 

 Willstatter and Page (1914) find is characteristic of the impure pig- 

 ment, but not of the pure crystals. The latter are insoluble in 

 petroleum ether. Kylin made the interesting discovery that the blue 

 color reaction is given not only by the mineral acids, but by acetic 

 and oxalic acids as well, and that dilute alkali changes the pigment 

 so that the tendency to give this reaction is greatly accelerated. 



Fucoxantlun. The chemical relation of fucoxanthin to the other 

 carotinoids is now known through the work of Willstatter and Page 

 (1914), who also determined the quantitative distribution of the dif- 

 ferent carotinoids in the olive-brown sea-weeds. Ultimate analyses 



