242 Naturalist at Large 



served the fish any useful purpose at all. Now explain that 

 if you can. 



This discussion may sound a little old-fashioned to a 

 modern specialist. Recent authors, among them Richard 

 Benedikt Goldschmidt of the University of California and 

 Ernst Mayr of the American Museum of New York, have 

 written fascinating books concerning the modern in- 

 terpretation of micro- and macro-evolution. The light 

 which modern genetics has thrown on evolution has been 

 carefully appraised; moreover, what it may be expected 

 to interpret in the future has not been neglected. Genetics 

 has thrown light, and a flood of light, on heredity and the 

 mechanism of inheritance. 



This is a very different thing from throwing light on 

 transformism, which is evolution. Mayr has shown that 

 the systematic zoologists, or the taxonomists, with, of 

 course, the paleontologists, are the ones who have made the 

 most extensive contributions to our knowledge. Whether 

 they will continue to do so in the future remains to be seen. 



But the sum total of what is really new is not greater 

 than the contribution to knowledge made by Hugo de 

 Vries in 1901, and notliing like so illuminating as the re- 

 statement of Jordan's Law of Evolution through Isolation 

 — which I am about to quote in the words of Tate Regan. 

 He has pointed out in these meaty paragraphs that this 

 isolation might be geographic or habitudinal: — 



This theory [that is, the mutation theory], which 

 explains adaptation as the result of a series of fortunate 

 accidents, appears to me to approximate to the old 

 "special creation" theory, and it was in opposing this 



