420 Comparative Study of Clilorojphyll. 



Should the precipitate formed be so fine as not to deposit 

 readily, we may hasten the process by passing a strong 

 current of carbon dioxide through the benzin. 



The precipitate is separated from the benzin by filtration, 

 is washed repeatedly with benzin, and evaporated on a water- 

 bath. "When dry the precipitate forms a nearly black 

 pulverisable mass, readily soluble in water and alcohol, 

 imparting to them a dark green colour. This precipitate is 

 " the green colouring-matter." 



Schunck's Method of prejMring two Colouring-Matters identical 

 with Fr6my's Phyllocyanin and Phylloxanthin.^ 



Fresh green leaves — preferably grass — are treated with 

 strong boiling alcohol, and the dark-green extract having 

 been poured off from the exhausted leaves, is allowed to stand 

 for a day or two, when it deposits a quantity of wax, fatty 

 matter, and other impurities, which had been extracted 

 along with the colouring-matter. The deposit being filtered 

 off, a current of hydrochloric acid gas is passed through 

 the filtrate. This produces a dark green, nearly black, 

 voluminous precipitate which increases in quantity on stand- 

 ing. The precipitate is separated by filtration, and washed 

 with alcohol along with an excess of acid. 



The precipitate contains, with impurities, chiefly of a fatty 

 nature, two distinct colouring-matters, identical with the 

 phyllocyanin and phylloxanthin of Fr^my. 



Tschirch's Method.^ 



To prepare the chlorophyllan oiHoppc-Seyler, which. Tschirch 

 believes to be identical with Pringsheim's hypochloriu and 

 Gautier's crystallisable chlorophyll, he proceeds either accord- 

 ing to Hoppe-Seyler's method, or according to A. Meyer, 

 or ultimately according to his own method, namely, thus — 



Wash the leaves (grass) with ether, treat them with 

 diluted hydrochloric acid, wash, make an extract with boiling 

 alcohol, filter it and evaporate down to half its original 

 volume, and on cooling hypochlorin will be deposited in 

 considerable quantities. 



* Annals of Botany, vol. iii. No. 9; page 88. 



t BericMe der dcutsclicn Botanischen Gcsellscliaft, i. 



