II THE ORIGIN OF SPECIES 79 



Existence, on Instinct, on Hybridism, on the Imper- 

 fection of the Geological Record, on Geographical 

 Distribution, have not only no equals, but, so far 

 as our knowledge goes, no competitors, within the 

 range of biological literature. And viewed as a 

 whole,we do not believe that, since the publica- 

 tion of Von Baer's " Researches on Development," 

 thirty years ago, any work has appeared calculated 

 to exert so large an influence, not only on the 

 future of Biology, but in extending the domination 

 of Science over regions of thought into which she 

 has, as yet hardly penetrated. 



