Contributions to the Chemistry of Chlorophyll. 449 



The plan I have pursued is as follows : — Fresh leaves — I prefer 

 grass with broad blades to any other material — are exhausted with 

 boiling spirits of wine containing from 80 — 82 per cent, of alcohol. 

 The green extract is filtered hot, and being allowed to stand for a 

 day or two away from the light, yields a dark-green voluminous 

 deposit, containing chlorophyll mixed with fatty and other matters. 

 This deposit is filtered off for further treatment, the pale-green 

 filtrate being rejected. The green mass on the filter is now to be 

 treated with a boiling solution of caustic soda in strong alcohol, 

 which dissolves it in part. The insoluble portion is filtered off, and 

 after washing with alcohol appears almost white.* Through the dark- 

 green filtrate a current of hydrochloric acid gas is then passed until 

 it acquires a strong acid reaction. The liquid first becomes yellowish- 

 green, but after some time the colour changes to a dull purplish- 

 green, and small crystalline needles arranged in stars, purple by 

 reflected and dull- green by transmitted light, begin to appear on the 



* Minute sparkling red crystals are always found interspersed in the amorphous 

 mass of which the residue left by alcohol for the most part consists. These crystals 

 are the chrysophyll of Hartsen, the erythrophyll of Bougarel, a very beautiful 

 substance, which may be freed from the impurities accompanying it in this case in 

 the following manner : — The residue, after washing with alcohol, is treated in the 

 cold with chloroform, which dissolves the chrysophyll, leaving the greater part of 

 the fatty matter behind. The yellow solution is filtered, mixed with a considerable 

 quantity of alcohol, and left to stand for a day or two in the dark, when it deposits 

 crystals of chrysophyll mixed with fatty matter. The deposit is filtered off, and 

 placed, without removal from the filter, in a hot water funnel ; here it is treated 

 with a little hot glacial acetic acid. This removes all the fatty, along with some 

 colouring, matter. The residue is dissolved in a little chloroform, and the solution, 

 having been mixed with several times its volume of absolute alcohol, is left to stand 

 in the dark. The next day a quantity of chrysophyll will have separated in crystals 

 with a golden lustre and of a deep orange or red colour by transmitted light. The 

 substance is rapidly bleached on exposure to air. In order to preserve it unchanged, 

 it should, after filtration and rapid drying, be put into a glass tube through which 

 a current of hydrogen is passed before sealing, then kept in the dark. According 

 to Arnaud ('Compt. Eend.' vol. 102, p. 1119, and vol. 104, p. 1293), chrysophyll is 

 identical with carotin. There can be no doubt that it contributes to the obscura- 

 tion at the blue end of the ordinary chlorophyll spectrum ; I have found it accom- 

 panying chlorophyll in all leaves that I have examined. Its solutions when 

 sufficiently dilute show two broad bands at the blue end, without the least trace of 

 absorption at any other part of the spectrum (fig. 1). 



Fig. 1. 



ttBCDEF G H 



Absorption Spectrum of Chrysophyll. 



VOL. XLIV. 



