52 SYNTHESIS BY SUNLIGHT 



of organic from inorganic substances in the green plant by the 

 agency of chlorophyll. 



Such a synthesis occurring in nature probably forms the first 

 step in the origin of life. For chlorophyll and protoplasm are 

 substances of far too complex chemical constitution to be regarded 

 as the first step in the evolution of the organic from the inorganic. 



Without the presence of organic material, when life was arising 

 in the world, any continuance of life would, however, be impossible. 



The process of evolution of simple organic substances having 

 once begun, as now experimentally demonstrated, substances of 

 more and more complex organic nature would arise from these with 

 additional uptake of energy. Later, organic colloids would be 

 formed, possessing meta-stable properties, and these would begin 

 to show the properties possessed by living matter of balanced 

 equilibrium, and up-and-down energy transformations following 

 variations in environment. 



There can be little question that such energy changes as are 

 above described occur at present, and are leading always to fresh 

 evolutions of more complex organic substances, and so towards life, 

 and equally is it true that they must occur on any planet containing 

 the necessary elements for the evolution of inorganic colloids and 

 exposed to light energy under suitable conditions of environment. 



