176 ORIGIN AND NATURE OF LIFE 



corner of the universe, and leaves us in the 

 unsatisfactory position of affirming not only 

 that we have no knowledge as to the mode of 

 origin of life — which is unfortunately true — 

 but that we never can acquire such knowledge, 

 which, it is to be hoped, is not true. Knowing 

 what we know, and believing what we believe, 

 as to the part played by evolution in the 

 development of terrestrial matter, we are, 

 I think (without denying the possibility of 

 the existence of life in other parts of the 

 universe), justified in regarding these cosmic 

 theories as inherently improbable — at least 

 in comparison with the solution of the problem 

 which the evolutionary hypothesis offers." 



It has been seen in following the evolution- 

 ary process, step by step, in the preceding 

 chapters, that even in the inorganic world 

 gigantic molecules can be built up. And 

 that as molecular complexity increases, and 

 the firmness of chemical union in the con- 

 stituent parts decreases, a delicate mobile 

 balance becomes established, easily destroyed 

 but, within the limits of its stability, capable 

 of oscillatory energy changes. 



Many of the properties of the molecules 

 of these inorganic colloids approximate to 

 those of the organic colloids found in living 

 structures. 



