350 



Mr. E. SchuDck. 



grass, from ivy leaves, from the leaves of the common thorn, and 

 from the fronds of Pteris aquilina. No difference conld be dis- 

 cerned between the different specimens obtained. 



Properties of Phyllocyanin. 



When dry, phyllocyanin has the appearance of a dark bine mass, 

 which may easily be reduced to a fine powder. It resembles indigo, 

 but when rnbbed with a hard body it remains blue, and does not 

 exhibit the coppery lustre which characterises indigo. Under a lens, 

 small white glistening points are seen clotting the mass, produced by 

 reflexion from crystalline surfaces. Examined nnder the microscope, 

 it is found to consist almost entirely of elongated rhomboidal, or 

 irregularly six-sided crystalline plates, which are generally opaque, 

 but when very thin are translucent and then appear olive-coloured by 

 transmitted light. Phyllocyanin is insoluble in water. It dissolves 

 in boiling alcohol, but a great part of the substance dissolved separates 

 out on the solution cooling, as a voluminous mass, consisting of 

 microscopic crystals. It is more soluble in ether, glacial acetic acid, 

 benzol, and carbon disulphide than in alcohol, bnt the best solvent is 

 chloroform, which takes up large quantities of phyllocyanin even in the 

 cold. A minute quantity of the substance imparts an intense colour 

 to any of these solvents, especially chloroform. It is only on diluting 

 largely that these solutions lose their opacity. They then appear of a 

 dull green or olive colour, and show the well-known and often 

 described spectrum of "acid chlorophyll," consisting of five bands of 

 various intensity. The solutions fluoresce, but not so strongly as 

 solutions of chlorophyll. 



When the ethereal solution is mixed with concentrated hydro- 

 chloric acid, the whole of the phyllocyanin is taken up by the acid, 

 yielding a dark greenish-blue solution, which sinks to the bottom. 

 Should phylloxanthin be present, it will be found in the upper 

 ethereal layer, which then shows a yellowish-green tint, and an ab- 

 sorption spectrum differing from that of phyllocyanin. The lower 

 greenish-blue solution shows when sufficiently dilute five absorption 

 bands, the spectrum, in fact, of the hydrochloric acid compound of 

 phyllocyanin, which differs widely from that of phyllocyanin itself. 



Phyllocyanin is almost insoluble in boiling petroleum ether, and 

 nearly insoluble in ligroin. It dissolves easily in warm aniline. 



Phyllocyanin contains nitrogen, but is free from sulphur. 



Action of Heat. — When heated on platinum, phyllocyanin gives 

 off an acid smell, then swells up considerably, evolving gas which 

 burns with a smoky flame, and leaves a voluminous charcoal, which 

 burns away slowly, a hardly visible trace of ash being left. When 

 heated slowly between two watch-glasses, it swells up slightly, and 



