1896.] NATURAL SCIENCES OF PHILADELPHIA. 217 



Comparing then this statement with what I have observed re- 

 garding the pigment under consideration we find that there is a 

 close similarity as to its solubility and that of carotin. 



With concentrated sulphuric acid the chromatophores changed 

 first to a greenish color and then to a decidedly purple-blue. This 

 same change of color was effected when concentrated sulphuric acid 

 was added to the chloroform solution. With iodine (in potassium 

 iodide) the chromatophores turned blue-green, like the color char- 

 acteristic of the Cyanophycess. 



According to Zimmermann* with a solution of iodine (e. g. aque- 

 ous solution of iodine and iodide of potassium) carotin is colored 

 greenish or greenish-yellow ; with concentrated sulphuric acid, first 

 violet and then indigo blue. 



There is evidently, therefore, also much resemblance between the 

 eflfect of iodine and concentrated sulphuric acid upon carotin and 

 the red pigment of Celastrus scandens. 



Lacking, however, complete correspondence I next determined to 

 discover if it approached xanthin more closely in its properties. It 

 differs from this in its most conspicuous, although on that account by 

 no means'most important property, its color. "Xanthin occurs in 

 yellow chromoplasts in amorphous form, and especially in small 

 granules.® Its alcoholic solution leaves on evaporation a wholly 

 amorphous resin-like mass. It is insoluble in water, little solu- 

 ble in ether, chloroform and benzine but more so in alcohol. 

 With concentrated sulphuric acid, the isolated pigment, as well as 

 the chromoplast takes first a greenish then a blue color ; with iodine 

 best used in the form of potassium iodide it becomes green.'" 



It will be seen from this that while the red pigment of Celastrus 

 scandens differs from xanthin in its solubility it agrees with it more 

 closely as regards the eflfect of sulphuric acid than does carotin. 

 Another striking resemblance with xanthin is the resin-like amorph- 

 ous residue left when the solvents are evaporated. 



The behavior of the coloring matter of the aril of the seed of 

 Celastrus scandens with different solvents and other reagents leads 



5 Ibid., p. 102. 



® It apj^ears to me of no great importance to distinguish between pigments 

 occurring in solution or in granules so long as we know no more about solu- 

 tions than we do at present. We consider pigments in solution if present in 

 such a fine state of division that the individual particles can no longer be recog- 

 nized. It must be admitted than such an distinction is purely arbitrary. 



" Zimmermann, Microtechnique, p. 103. 



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