248 THE MEANING OF EVOLUTION 



opinion of his own based on some other ground than 

 his chemistry, but so far as he is a chemist, he has 

 no opinion. The chemical side of Hfe is being very 

 carefully and very fully investigated. We are cer- 

 tainly being brought nearer to the borders of the 

 living substance. We are rapidly gaining fuller 

 knowledge of the physical and chemical processes 

 which constitute life, or with which life is always as- 

 sociated. If we gain this knowledge we shall be in 

 better position to solve many of our other problems. 

 Even then there is a problem which preceded and 

 which will possibly always defy solution. How did 

 life originate? Has it developed out of chemical 

 and physical activities which we know as heat, light 

 or electricity? If so, what were the conditions under 

 which it developed? If we understand the nature of 

 life, and the conditions under which it developed, we 

 may be able to produce it at will. 



A few scientists may hope dimly that this will 

 be attained. I suspect a great majority believe it 

 to be impossible, and that the question as to whether 

 life evolved upon this planet, or this planet became 

 infected with life through meteoric dust from some 

 other center, will forever remain an unsolved prob- 

 lem. 



