( .\im\<nbs i.\ rill' CRYPTOGAMS 99 



due to the formation of a hydrochloride of the composition (',,,H i4 O , 

 4HC1, the yellow pigment restored by alkali still containing one mole- 

 cule of Hri. The instability of the pigment in the presence of strong 

 alkali, which was observed by Tswett, was confirmed on the pure 

 substance, it being shown that a new substance was formed which, 

 when set free from the alkali by water, showed characteristic spectro- 

 scopic and solubility properties. It was found that the effect of alkali 

 in increasing the sensitiveness of fucoxanthin solutions towards the 

 blue color reaction with acids, which Kylin noted, was due to this 

 modified pigment. Willstiitter and Page observed that as little as 

 0.001 per cent HC1 would give the blue color with a concentrated 

 ether solution of the pigment, after its modification with alkali. 



Fucoxanthin appears to be an even more intense pigment than 

 carotin or xanthophyll from the observations of Willstiitter and Page, 

 who found that 85 mm. of 0.2 per cent K 2 Cr 2 O 7 has the color equiva- 

 lent of 108 mm. of xanthophyll, or 80 mm. of carotin, but only 50 mm. 

 of fucoxanthin, using in each case a 5 X 10" 5 molar concentration 

 of pigment. 



Other interesting properties of fucoxanthin observed by these inves- 

 tigators were the formation of oxonium salts, a crystalline iodide, 

 C 40 H 54 U I 4 , and a bleached oxidation product C 40 H 54 O 1G . In con- 

 nection with the last named product it was found that the crystals of 

 pigment are much more stable than carotin or xanthophyll, but that 

 the solutions, especially benzene solutions, bleach readily. 



Regarding the quantitative distribution of the carotinoids in Phaeo- 

 phyceae, Willstiitter and Page give the following figures on both the 

 fresh and dry basis for species representing the three principal orders 

 of these plants. 



Fresh A Into Dry Algae 



Fucoxan- Xantho- Fuc.ran- Xnntho- 



thin Carotin phi/11 thin Camlin i>lii/ll 



percent percent percent percent percent percent 



Fucus 0.0169 0.0089 0.0087 0.0593 0.0312 0.0305 



Dictyota .0250 .0057 .0063 



Laminaria .0081 .0006 .0038 .0528 .0038 .0243 



Willstiitter and Page gave some attention to the character of the 

 xanthophyll present. They were unable to observe any properties 

 which would serve to distinguish the xanthophyll isolated by them 

 from the crystalline xanthophyll of higher green plants. This result 

 throws doubt on the existence of a special fucoxaiithophyll in the 



