120 Schimck . — The Chemistry of Chlorophyll. 
kept for some time in hydrogen gas that caused the negative 
result on subsequent treatment with aniline in the experiment 
above described. If C0 2 be, as I suppose, essential to the 
constitution of chlorophyll it must be equally so to that 
of anilophyll, which is from my point of view simply a sub- 
stitution product of unaltered chlorophyll. If this be the 
constitution of chlorophyll it will be readily conceived how 
difficult it would be to reconstruct the natural substance by 
artificial means, for a mere knowledge of its proximate con- 
stituents, all of them endowed with weak affinities, would 
constitute merely the first step towards the accomplishment 
of the task. 
The presence of a body having a chemical constitution 
such as I attribute to chlorophyll would, it is evident, serve 
a useful purpose in the vegetable economy. The carbonic 
acid forming one of its constituents being held more loosely 
combined than in an ordinary carbonate, and yet in a state 
of greater condensation than it would be in a mere watery 
solution, would be in a favourable condition for transfer to 
the assimilating plasma which effects its decomposition with 
elimination of oxygen, and the chlorophyll would then be ^ 
in a state to take up fresh quantities of C0 2 , acting therefore 
as a carrier of carbonic acid in the plant, just as haemo- 
globin serves to convey oxygen in the animal economy. 
