46 THE METHODS AND 



Lastly I suppose it is self-evident that 

 they have a bearing on the problem of Evolu- 

 tion. The facts of heredity and variation 

 are the materials out of which all theories of 

 Evolution are constructed. At last by genetic 

 methods we are beginning to obtain such 

 facts of unimpeachable quality, and free 

 from the flaws that were inevitable in older 

 collections. From a survey of these materials 

 we see something of the changes which will 

 have to be made in the orthodox edifice to 

 admit of their incorporation, but he must be 

 rash indeed who would now attempt a com- 

 prehensive reconstruction. The results of 

 genetic research are so bewilderingly novel 

 that we need time and an exhaustive study 

 of their inter-relations before we can hope 

 to see them in proper value and perspective. 

 In all the discussions of the stability and 

 fitness of species who ever contemplated 



