70 Schunck . — Zife Chemistry of Chlorophyll. 
Looking at the method of preparation one would be inclined 
to suspect the presence of sodium in chlorophyll-green ; 
in a later memoir, indeed, Hansen admits that his product 
is a sodium compound, the sodium being removable by 
acids ; but he does not describe the substance left behind 
by the acid. The latter, i.e. the liberated colouring matter, 
is, he admits, like chlorophyll itself, easily altered by strong 
acids, for which reason it is advisable to use a weak acid, such 
as boric acid, not sulphuric or hydrochloric acid, for the re- 
moval of the sodium. Any one not intimately acquainted with 
the subject would be inclined to infer, from what has been 
stated, that Hansen’s product, though not itself chlorophyll, 
is at least a sodium compound of chlorophyll, and that by 
careful treatment of the compound the colouring matter could 
be isolated. I do not, however, believe this to be the case. 
My own experiments lead me to believe that by the action of 
caustic alkali chlorophyll undergoes a change, which is not 
indeed apparent to the eye, but which manifests itself when 
the alkaline chlorophyll is submitted to the action of acids. 
I have very little doubt that, when Hansen comes to investi- 
gate the action of strong acids on his compound he will obtain 
a product differing from that due to the action of acid on 
untreated chlorophyll. I shall return to this part of the 
subject presently. 
The general conclusion at which I arrive is this — that 
chlorophyll has not hitherto been obtained in such a state 
of purity as to enable us to describe its physical and chemical 
properties. That it can never be isolated I will not undertake 
to say, but the difficulties, in consequence of its great liability 
to change, will be considerable. To reconstruct chlorophyll 
from its products of decomposition, when these are all known, 
would perhaps be a task more easily accomplished. Whether, 
when it has been isolated or reconstructed, it will be found 
to assume a crystalline form, cannot of course be foretold ; 
but I am inclined to think, that as it exists in the plant, it 
is amorphous. 
