CHAPTER III 



Are the Gene Mutations Observed in Experimental 

 Genetics the Basic Materials of Progressive Evolution? 



WE TAKE up in the present chapter the question 

 proposed at the end of the preceding. Do the gene 

 mutations observed by the students of genetics constitute the 

 types of change of genie materials that are required for evo- 

 lution; and particularly for progressive evolution? Are they 

 steps in evolutionary progress ? 



Here we frequently meet an argument from definition. 

 Evolution, it is urged, requires, and is finally based on, 

 changes in the constitution of the genie materials. And any 

 change in the constitution of the genie materials would be by 

 definition a gene mutation. Hence it argued that evolution 

 certainly rests on gene mutations. But such argumentation 

 has no relation to observed facts; it was equally valid before 

 any mutations were seen. The question of interest is: Has 

 genetic science actually before it steps in evolution? Do the 

 observed gene mutations constitute the type of change that 

 has resulted in progressive evolution ? It is to this question that 

 we shall address ourselves. Our discussion relates only to 

 observed types of change; not to conceivable but unseen types. 

 What may be a definite answer to these questions is now 

 emerging before us. On it there are several lines of evidence. 

 First is the fact, already set forth, that the agents known to 

 produce gene mutations are definitely destructive agents. 

 They injure the organism in all its parts and functions, 

 including its genetic parts and functions, including its germ 

 plasm. By an astounding paradox, we are asked to believe that 



