ASPECTS OF KINETIC EVOLUTION 2 29 



pretation which has been put upon them. They serve only as 

 samples of groups of facts to which the interpretation is applic- 

 able, the primary object being, not to demonstrate conclusions by 

 formal arguments, but to indicate a standpoint, the correct- 

 ness of which may be judged by other observers from the facts 

 encountered in their own fields of investigation. 



To learn the nature and causes of evolution it has not been 

 sufficient to explore and explain the barriers between the species. 

 It is necessary to go inside the species and to ascertain, if pos- 

 sible, which of the many differences between the component 

 individuals represent forward steps in organic development, and 

 which mere lateral diversions or displacements. 



DARWIN'S DISCOVERY OF VARIATION. 



Much has been written to show that Darwin did not discover 

 evolution, as popularly supposed, since the idea may be traced 

 back to the Greek philosophers or to the Hindus, and had been 

 entertained in modern times by Lamarck and several others 

 of Darwin's predecessors. And yet, the popular impression, 

 though perhaps inexact as to technical terms, is more just than 

 that of many scientific critics. Darwin was able to secure 

 general interest and confidence in an idea previously indefinite, 

 intangible and practically useless. If Darwin did not discover 

 evolution or even invent entirely new arguments in its favor, he 

 performed a more valuable and unique service in establishing 

 the fundamental fact of variation, without which all evolutionary 

 ideas would have remained empty and sterile speculations, as 

 they had remained during the two thousand years preceding. 



Darwin discovered what is still more important to the scien- 

 tific world than the abstract idea or theory of evolution, namely 

 the means of evolution, which is variation. Darwin was the 

 first to adequately appreciate the fact that species do not consist 

 of individuals identical in form or structure, but of those which 

 are diverse, each different from the others in a greater or lesser 

 degree. Upon the fact of variation Darwin also based his 

 theory of evolution by natural selection and other environmental 

 causes, a theory which has had great popularity in the general 

 scientific world, because it afforded the most concrete suggestion 



