38 DR. EDWARD SCIITJNCK ON THE 



or some other leaf-constituent, it is not so easy to pronounce 

 a decided opinion. This colouring-matter, called by Berze- 

 lius xanthophyll, is suppsed by some to be identical with 

 phylloxanthin, the yellow substance which, according to 

 Fremy and others, always accompanies the chlorophyll of 

 green leaves. Of its properties little is known; and that 

 little T find to be more or less incorrect. It is said to be 

 soluble in alcohol and ether, insoluble in water, to turn 

 green with acids, and to show a peculiar absorption-spectrum 

 different to that of chlorophyll. These statements require 

 correction. It is, in fact, soluble in water, but insoluble 

 in ether ; it does not turn green with acids ; and the ab- 

 sorption-bands which it shows are due to an admixture of 

 chlorophyll, as a few simple experiments are sufficient to 

 show. Having taken some bright yellow elm leaves, I ex- 

 tracted them with boiling spirits of wine, and obtained a 

 greenish yellow liquid, which, after filtration, showed only 

 the dark absorption-band in the red corresponding to band 

 I. of the chlorophyll spectrum. I evaporated the extract 

 in the water-bath, and during evaporation observed a 

 deposit form on the sides of the dish consisting of green 

 fat-like masses. On adding water to the residue a portion 

 dissolved, yielding a golden-yellow liquid, while the fat- 

 like masses remained undissolved. After pouring off the 

 liquid and washing the residue with water, the latter was 

 dissolved in hot alcohol, when it gave a yellowish-green 

 liquid which showed all the absorption-bands of chlorophyll 

 distinctly. The golden-yellow watery solution on the other 

 hand showed no trace of absorption-bands, merely a general 

 darkening of the blue end of the spectrum. Its colour was 

 evidently due to a yellow colouring-matter contained in it. 

 It gave an abundant yellow precipitate with lead acetate, 

 and a dark green precipitate with ferric chloride. It also 

 contained a considerable quantity of tannin, since it yielded 



