ASPECTS OF KINETIC EVOLUTION 287 



has also been applied as a philosophical principle in the elucida- 

 tion of many facts and problems outside the organic series. 

 After being once adequately presented such an integration of 

 knowledge could scarcely have failed to command respectful 

 consideration, and its general acceptance has already become so 

 much a matter of course that the word evolution is not uncom- 

 monly used in a much narrower sense and identified with one or 

 the other of the theories which have been invented to explain 

 the methods and immediate causes of the process of organic 

 change, a subject upon which there is still no lack of differing 

 opinions. 



Although the doctrine of the independent creation of species 

 has been set aside, it has proved much more difficult to elimi- 

 nate, even from the minds of the biologists themselves, what may 

 be called the static view of nature. It is not strange that the 

 stability of species should have first impressed the scientific 

 mind. When closely similar plants and animals, not distin- 

 guished by the popular intelligence, were found to differ in 

 minute particulars which were, nevertheless, invariably trans- 

 mitted to their offspring, a creative pre-arrangement seemed to 

 be the only explanation, and the apparently gratuitous variety 

 of organic forms was very naturally ascribed to causes outside 

 the reach of human comprehension. 



Later, when it was realized that in spite of the wonderful sta- 

 bility of species the component individuals are never identical 

 in all particulars, but differ endlessly among themselves, and 

 that even these minor differences tend to reproduce themselves, 

 the theory of the gradual transformation and subdivision of spe- 

 cies became a logical possibility, and the search at once began 

 for a method by which variations of a certain kind could be 

 accumulated instead of cancelling each other and disappearing 

 in a stationary average. 



The explanation of evolution is the biological task now re- 

 ceiving the widest and most earnest attention, and is the subject, 

 directly or indirectly, of a literature so vast that even a casual 

 reading of all the books and papers as they come from the press 

 would be a formidable undertaking. Such multiplicity of pub- 

 lications betokens, of course, a corresponding diversity of opin- 



