Schunck . — The Chemistry of Chlorophyll. 71 
Physical and Chemical Properties oe Chlorophyll. 
If my views are correct it follows that our knowledge of 
the physical and chemical properties of chlorophyll must be 
limited. Of a body which can only be obtained in a state of 
solution, and which is changed or decomposed on attempting 
to isolate it, we can know but little. If it were possible to 
obtain a solution of chlorophyll containing no other substance, 
or at least no other coloured constituent, we should be better 
off ; but we are obliged to content ourselves with treating 
leaves with some appropriate solvent, and drawing more or 
less correct conclusions from the behaviour of the solution, 
which in no case is quite free from foreign substances inter- 
fering with the chlorophyll-reactions. 
Professor Stokes and others have attempted to purify 
chlorophyll by agitating alcoholic leaf- extracts with carbon 
disulphide or benzol, but, as might be expected, with only 
partial success, since no complete separation of two substances 
contained in the same solution can be effected by agitating 
the solution with some liquid, in which one of the two is more 
soluble than the other ; the two solvents taking up both 
substances, though in different relative proportions. A solu- 
tion of chlorophyll of sufficient purity for some purposes may 
be obtained by mixing an alcoholic extract of grass with 
about twice its volume of water, and then agitating the milky 
liquid with ordinary ether or petroleum ether. The latter 
takes up the chlorophyll along with other substances, a quan- 
tity of yellow colouring matters and other impurities being 
left in solution in the lower watery stratum. 
Most observers agree in stating that chlorophyll is insoluble 
in water. Hansen has, however, endeavoured to prove that, 
when pure, it is really soluble in water, the insolubility usually 
observed being, according to him, due to its combination with 
fatty matter in the vegetable organism. Chlorophyll is soluble 
in alcohol, ether, chloroform, carbon disulphide, ethereal and 
fatty oils, and similar menstrua. These solutions show the 
well-known bright green colour and red fluorescence as well as 
