66 



THE THEORY OF THE GENE 



TABLE I 



Eecubkent Mutations and Allelomobphic Series 



There is also another fact that a study of the mutation 

 process has brought to our attention. The same mutation 

 may recur again and again. A list of these recurrent mu- 

 tations of Drosophila is given above. The reappearance 

 of the same mutant indicates that we are dealing with 

 a specific and orderly process. Its recurrence recalls 

 Galton's famous analogy of a polygon. Each change 

 corresponds to a new stable position (here perhaps in a 



