104 BOTANICAL MICROTECHNIQUE. 



chlorophyll. The pigment soluble in water is at present 

 commonly called phycoerythrin. 



Phycoerythrin is, according to Schiitt (II and IV), in- 

 soluble in alcohol, ether, benzole, benzine, carbon bisul- 

 phide, glacial acetic acid, and fatty oils. Its saturated 

 aqueous solution appears by transmitted light dark bluish 

 red, by reflected light more or less yellow, on account of its 

 deep orange-yellow fluorescence. Its absorption-spectrum 

 is distinguished from that of chlorophyll, according to 

 Schutt's investigations (II), especially by the fact that its 

 maximum of brilliancy is at the point in the red where the 

 strongest absorption-band of chlorophyll occurs. 



C. Coloring Matters of the P hoe op hy c e ce . 



176. Millardet has recognized three pigments in the chro- 

 matophores of the Phceophycece : chlorophyllin, phycoxan- 

 thin, and phycophaein. The first two of these are, accord- 

 ing to Hansen (II), identical with chlorophyll-green and 

 chlorophyll-yellow ; that is, with chlorophyll and carotin. 



Phycophcein is readily soluble in water, especially in hot 

 water; its saturated solution has a deep red-brown color 

 and shows with the microspectroscope a regular increase of 

 absorption from the red to the blue end of the spectrum 

 without any absorption-bands. It is also little soluble in 

 dilute, and insoluble in absolute, alcohol, as also in ether, 

 carbon bisulphide, benzol, benzine, and fatty oils. It is 

 more or less completely precipitated by acids from its 

 aqueous solution, incompletely so by caustic soda, and not 

 at all by ammonia and salts of the alkalies. Salts of the 

 alkaline earths precipitate it (Schiitt III). 



77. Coloring Matters of the Cy a n op h y c e ce . 



177. Three different pigments have been isolated by 

 Reinke (II, 405) from an Oscillatoria, which he calls chloro- 

 phyll, phycoxanthin, and phycocyanin. Of these the first 

 must certainly be identical with ordinary chlorophyll, but 

 whether the phycoxanthin is to be identified with carotin is 



