Contributions to the Chemistry of Chlorophyll. 355 



caustic potash or soda-lye, it dissolves entirely. The solution has the 

 same colour as other phyllocyanin solutions, and shows a similar 

 spectrum, but with the bands less distinctly marked. It gives pre- 

 cipitates of various shades of green, with earthy and metallic salts, 

 such as the chlorides of barium and calcium, lead acetate, and copper 

 acetate. These might, perhaps, be regarded as compounds of phyllo- 

 cyanin, and be called phyllocyanates. Nevertheless it is easy to 

 show that by mere solution in alkali, phyllocyanin undergoes a com- 

 plete change. If the alkaline solution be mixed with an excess of 

 acetic acid, and then shaken up with ether, the precipitate with acid 

 dissolves in the ether, the solution having the colour of a phyllocyauin 

 solution, and showing the characteristic absorption-bands ; but if the 

 solution be left to stand in contact with excess of acid for some time, 

 its colour changes from olive to a brown or smoke colour, and it now 

 shows quite a different and very elegant spectrum, characterised by 

 two bands in the red, one of which is thin and nearer the red end 

 than the first band of phyllocyanin, and two very fine but distinct 

 bands in the green, the third and fourth bands of phyllocyanin 

 having disappeared, while the fifth still remains. Since phyllocyanin, 

 before solution in alkali, is not changed appreciably by acetic acid, 

 even on boiling, it is evident that by the action of alkali it is in some 

 way metamorphosed, so as to be liable to further change when acted 

 on by the acid. In preparing this product of the successive action 

 of alkali and acid, care must be taken to operate in the cold, for if 

 hot alkaline lye be used, an entirely different product is formed. It 

 is deposited from a boiling alcoholic solution in microscopic crystals, 

 which are quite opaque, even in a strong light, and resemble crystal- 

 lised phyllocyanin. In none of the various memoirs on chlorophyll 

 that have come under my notice have I seen any spectrum figured or 

 described at all resembling that of the solutions of this substance. 

 The spectrum is distinctly seen, even in exceedingly dilute solutions. 



The next product of the action of alkalis on phyllocyanin is formed 

 when hot alkaline lye is employed. In order to obtain it, a solution 

 of phyllocyanin in boiling alcohol is mixed with alcoholic potash or 

 soda, and boiled. On standing, the solution yields a semi-crystalline 

 deposit of a fine purple colour by reflected light, consisting of a potas- 

 sium or sodium compound of the product formed. This is filtered off, 

 washed with alcohol, and then dissolved in water. The solution 

 gives with acetic acid a green flocculent precipitate, which is 

 filtered off, washed, and dissolved in boiling glacial acetic acid. 

 This solution on standing deposits small crystalline rosettes, which 

 are green by transmitted light, and of a fine purple by reflected light. 

 The solutions of this substance have a dull purple colour, and exhibit 

 a distinct spectrum, characterised by a broad very dark band in the 

 green. 



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