Contributions to the Chemistry of Chlorophyll. 353 



its watery solution has a strong acid reaction and a sour and at the 

 same time very bitter taste ; the solution gives no coloration with 

 ferric chloride ; it evolves ammonia when boiled with caustic potash, 

 and it reduces Fehling's solution on boiling. 



It appears, therefore, that by insolation, phyllocyanin yields pro- 

 ducts which resemble, if they are not identical with, those due to the 

 action of nitric and chromic acids. It is possible that some of these 

 products may be contained in faded autumnal leaves after the chloro- 

 phyll has disappeared, but their indefinite character would render 

 their identification very difficult. Grreen leaves, in becoming yellow, 

 pass through a stage in which they yield when treated with alcohol 

 an extract which, though quite yellow and non-fluorescent, shows a 

 strong absorption band in the red. Of this fact I was forcibly 

 reminded when watching the progressive changes of phyllocyanin 

 during insolation. 



Action of Chlorine. — On passing a current of chlorine gas through 

 a chloroformic solution of phyllocyanin, the first effect observed is a 

 change of colour in the solution from dull green to a bright grass- 

 green, the latter colour closely resembling that of a solution of chlo- 

 rophyll. The solution shows an absorption spectrum which coincides 

 neither with that of chlorophyll nor with that of phyllocyanin. 



On standing for a day or two the solution loses its bright green 

 colour, and acquires a reddish hue, with a green tint at the edges 

 where the thickness of the liquid is less. It now shows the same 

 number of bands as a phyllocyanin solution, but the bands are all 

 nearer the red end. On evaporation it leaves a greenish-brown 

 amorphous residue. On passing more chlorine through the chloro- 

 formic solution of phyllocyanin the green colour seen at first dis- 

 appears, the solution becomes yellow, at last pale yellow, all the bands 

 characteristic of phyllocyanin at the same time disappearing. The 

 liquid leaves, on evaporation, a yellow amorphous residue like resin. 

 This, after heating in the water-bath to drive away all traces of 

 hydrochloric acid, is found to contain chlorine. It does not dissolve 

 in boiling water, but merely softens. It is easily soluble in alcohol, 

 the solution being yellow and showing much obscuration in the blue 

 of the spectrum, but no absorption bands even when very dilute. 

 It dissolves only in part when treated with caustic potash lye. 



Action of Bromine. — On the addition of a little bromine to a chloro- 

 formic solution of phyllocyanin, the solution acquires a bright grass- 

 green colour, and now shows four absorption bands. On adding an 

 excess of bromine to the solution, heating and evaporating, an olive- 

 coloured amorphous product, containing bromine, is obtained, which 

 dissolves easily in alcohol. The solution is brownish-red, and shows 

 a spectrum similar to that of phyllocyanin, but having the bands all 

 nearer the red end. 



