HUXLEY AND EVOLUTION. 331 



of a derivative relationship between them. The only pos- 

 sible inductive evidence of relationship would be a large 

 number of examples of actual transition from species to 

 species; but these, taking no account of merely inferential 

 transitions, are facts of almost unparalleled infrequency, 

 and at best are not of such observed frequency as to 

 justify a generalization covering the whole field of life 

 past and present. 



