Contributions to the Chemistry of Chlorophyll. 351 



■becomes charred. On the lower glass there is left a black mass 

 which imparts no colour to boiling chloroform, and seems to be simply 

 charcoal. On the upper glass, there is found a small quantity of 

 brownish sublimate, which, under the microscope, is seen to consist 

 partly of crystalline needles, partly of regular rhombic crystals which 

 are honey-yellow by transmitted light. 



When slowly heated in an air bath to 160°, phyllocyanin remains 

 apparently unchanged. It is still completely soluble in chloroform, 

 the solution showing the usual absorption bands. On heating, how- 

 ever, to 180°, complete decomposition takes place, bub without any 

 change of volume in the substance. The charred mass now imparts 

 to boiling chloroform only a very faint green tinge, and when heated 

 in a tube, gives off no empyreumatic products, only a slight odour 

 of hydrocyanic acid. 



Action, of Oxidisers. — On adding a little nitric acid to a boiling 

 saturated solution of phyllocyanin in glacial acetic acid, the solution 

 immediately becomes yellow, but without evolution of nitrous 

 fumes. It deposits nothing on cooling and standing. On the 

 addition of water it gives a dirty green flocculent precipitate, the 

 filtrate from which is still yellow, but shows no absorption bands. 

 The precipitate dissolves easily in alcohol, giving a yellow solution, 

 which shows a spectrum differing from that of phyllocyanin. 



Phyllocyanin itself, treated with boiling dilate nitric acid is 

 rapidly decomposed and dissolved with evolution of nitrous fumes. 

 The solution evaporated in the water-bath leaves a residue which, 

 treated with water, dissolves in part. The nitrate has a bitter 

 taste, and leaves, on evaporation, a soft yellow residue, in which, on 

 standing, some colourless crystalline needles are formed. The portion 

 insoluble in water dissolves easily in alcohol, giving a yellow solution 

 which, on evaporation, leaves a residue having a crystalline ap- 

 pearance, but not really crystalline when examined under the 

 microscope. 



A hot concentrated solution of phyllocyanin in glacial acetic acid 

 becomes, on the addition of a little chromic acid, yellowish- green, 

 but deposits nothing on cooling. The solution gives with water a. 

 dull green precipitate, the nitrate from which is yellow, and shows no 

 absorption bands, while the precipitate itself, treated with ether, gives 

 a solution which differs somewhat as regards colour and absorption 

 bands from a solution of phyllocyanin. 



Phyllocyanin treated with a watery solution of chromic acid, to 

 which a little sulphuric acid has been added, is decomposed with 

 much effervescence, giving a green solution, which, after evaporation, 

 leaves a residue yielding to solvents only amorphous products. 



Insolation. — I will introduce here what I have to say regarding the 

 effect of insolation on phyllocyanin, because there can be no doubt 



VOL. XXXIX. 2 A 



