180 ORIGIN AND NATURE OF LIFE 



dioxide and water, so that these constitute 

 parts of the cell-colloid ; oxygen is then split off 

 and the carbon, hydrogen and a less amount 

 of oxygen, are built up into those organic, 

 energy-containing bodies described in a pre- 

 vious chapter. These bodies are built up 

 as part of the colloidal complex of the cell, 

 until an excess of them is present, when they 

 separate out as reserve carbohydrates, fats 

 and proteins. From time to time these are 

 dissolved out and transported in the plant 

 sap to other parts of the plant, to supply 

 energy and serve as materials for growth, 

 and the plant in all its parts goes on increasing 

 and growing. This organic growth afterwards 

 serves as food for the rest of the world of 

 living organisms. 



The green colouring matter wrested from 

 its connection with the living colloid of the 

 cell in which it occurs is almost devoid of 

 power to produce these changes. It may 

 be readily dissolved out by solvents such as 

 alcohol, chloroform or benzene, then sus- 

 pended in water, and exposed to sunlight in 

 presence of those inorganic constituents which 

 in its normal situation it transmutes into 

 organic matter. But under such conditions 

 an infinitesimal amount only of one of the 

 first products of organic synthesis is obtained 



