SHORTER ARTICLES AND DISCUSSION 



EVOLUTION WITHOUT ISOLATION 



This is the title of a brief but interesting article by 0. F. 

 Cook, in the American Naturalist for November, 1908. My 

 response to the same has been delayed by the pressure of other 

 things. 



I fully agree with Dr. Cook in his statement that ' ' The choice 

 of words is worthy of careful consideration, but words should 

 not lead us away from the broader issue of biological facts." 



We both maintain that there may be evolution without isola- 

 tion ; but I do not see how he can reconcile the following state- 

 ments, found in the above mentioned article, with the facts of 

 nature. "The separation of a species into two or more parts 

 allows the parts to become different, but there is every reason to 

 believe that evolutionary changes of tin same kind would take 

 place, if the species were not divided." Again: "Isolation, 

 tlii.ii'jh making more species, imprdrs i volution." Does he mean 

 that if man and the anthropoid apes had remained one freely 



have been reached than has been attained by man under the con- 

 dition of isolation between him and the apes? Does he mean 

 that the progress of the mammals, as a whole, would have been 

 more rapid, if they had remained one constantly intergenerating 

 species? Does he mean that, in the case of mammals, "changes 



in power to live, some in the sea like the whales and the por- 

 poises, some on the land, some on the trees, some in hand-made 

 houses, would all have taken place, if we, the mammals, had re- 

 mained one species ' Would these changes have come in succes- 



