Carbon Assimilation. 
89 
the carbon dioxide of the air to a greater concentration, on account 
of its property to take up more carbon dioxide at lower temperature 
suited to increase of assimilation under natural conditions. The 
carbon dioxide wanders on to the place of smallest carbon dioxide 
pressure. 
The real assimilation process we can differentiate into several 
sub-processes. Chlorophyll takes up carbon dioxide and at the 
same time forms a dissociable compound. One must suppose 
that this compound takes up light energy, and thereby undergoes 
rearrangement into an isomer of greater energy content, which is 
suited for its own disintegration. A transformation product of 
carbonic acid which can be split off enzymatically with loss of 
energy, must be imagined as intermediate product, as the obser¬ 
vation recorded in the first chapter makes it very probable that a 
part of the assimilation process is of enzymatic nature. 
There is only known one isomer of carbonic acid of peroxide 
nature to which could be ascribed the role of intermediate product, 
performic acid, obtained in solution by J. d’Ans and W. Frey, which 
easily dissociates into carbon dioxide and water. In the assimilation 
process one must of course imagine another way of dissociation of 
the intermediate product, namely, its disintegration with evolution 
of oxygen. 
As for performic acid, various structural formulae can be 
considered 
O—OH 
/ 
C 
/ % 
H O 
Formylhydroperoxide. 
H O 
\ / 
and C 
/ \ 
HO O 
Formaldehydeperoxide. 
so it is quite possible that the intermediate product of photo¬ 
synthesis bound to chlorophyll is a peroxide other than the known 
substance, performic acid.” 
In our opinion this latter part of Willstatter’s theory, which is 
based on his experiments with chlorophyll sols and carbon dioxide, 
is due to premature and incorrect interpretation of his experimental 
results. These, briefly, are as follows. In a system consisting of a 
chlorophyll sol and carbon dioxide, a certain amount of carbon 
dioxide will be absorbed by the water constituting the dispersion 
medium, and a further quantity will be used in the production of 
phaeophytin according to the equation 
