528 TRANSACTIONS OF SECTION D. 
colouring matter of the plant acting as a transformer of light energy into 
chemical energy. 
A little reflection shows that this present state of affairs must have evolved 
in complexity from something more simple existing at the commencement. 
For chlorophyll, which now acts as the transformer, is itself one of the most 
complex of known organic substances, and could not have been the first organic 
substance to evolve from inorganic matter. 
In considering the origin of life, the start must be made in a purely 
inorganic world without a trace of organic matter, either plant or animal. 
As Schafer has pointed out, any other supposition merely removes the seat 
of origin to some conveniently remote planet, and pushes the origin back 
farther in time, but brings us no nearer to a real solution. 
The earlier theories and views as to spontaneous generation all possess 
the error of attempting to start life amidst organic nutritive material which 
could not be there until life had already appeared. 
The complex organic substances, such as carbohydrates, fats, proteins, and 
all the many other organic cell constituents, are late products along the line 
of evolution of life, and the beginning lies at a level much below that of the 
bacterium or diatom. 
As a result of about eighteen months of experimental work, we have, we 
believe, obtained evidence of the first organic step in the evolution. 
When dilute solutions of colloidal: ferric hydroxide, or the corresponding 
uranium compound, are exposed to strong sunlight, or the light of a mercury 
arc, there are synthesised the same organic compounds which are at present 
formed as the first stage in the process of organic synthesis by the green 
plant, namely, formaldehyde and formic acid. 
If now we consider a planet exposed to the proper conditions of tempera- 
- ture and sunlight, that chain of events can be followed, which not only can 
but must occur. At first, as the planet cools down, only elements would be 
present, at a lower temperature binary compounds form, next simple crystal- 
loidal salts arise. Then, by the union of single molecules into groups of 
fifty or sixty, colloidal aggregates appear. As these colloidal aggregates 
Increase in complexity, they also become more delicately balanced in structure, 
and are meta-stable or labile, that is, they are easily destroyed by sudden 
changes in environment, but, within certain limits, are peculiarly sensitive to 
energy changes, and can take up energy in one form and transform it into 
another. 
This is the stage at which we take the matter up in our work. These 
labile colloids take up water and carbon dioxide, and, utilising the sunlight 
streaming upon the plant, produce the simplest organic structures. 
Next these simpler organic structures, reacting with themselves, and with 
nitrogenous inorganic matter, continue the process and build up more and 
more complex, and also more labile, organic colloids, until finally these acquire 
the property of transforming light energy into chemical energy. 
The problem of the origin of life hence acquires, as stated by one of us 
at the Dundee meeting of the Association, the aspect of an experimental 
inquiry with vast opportunities for obtaining more exact knowledge. 
From this first step in the organic synthesis advance must be made to 
study how more and more complex organic compounds can be evolved. 
But it is clear that by the continued action of this ‘law of molecular com- 
plexity’ life must originate, that forms of life are now originating, that the 
origin of life was no fortuitous accident, and that the same processes are guiding 
life onwards to higher evolution in a progressive creation. 
4. On the Phylogeny of the Carapace and on the Affinities of the 
Leathery Turtle, Dermochelys Coriacea. By Professor J. VErsuuys. 
See Appendix, p. 791. 
