ASPECTS OF KINETIC EVOLUTION 20,1 



pletely pervaded all our forms of thought and expression ; it has 

 been the general base and background of evolutionary science. 

 The average of biological opinion remains very nearly in the 

 same place as Darwin's original announcement of a theory of 

 environmental causes of evolution. The environment is sup- 

 posed to bring about the variations and to select and preserve 

 those having adaptive value, and thus to cause evolution. 

 Though Darwin himself appreciated in later years the tentative 

 character of this inference and sought in every direction for 

 contributing agencies to strengthen and support it, some of his 

 followers have had no such reluctance in crystallizing the idea 

 of environmental causes into definite formulae which are still 

 the shibboleths of evolutionary orthodoxy. President David 

 Starr Jordan not long ago quoted an interesting paragraph from 

 the evolutionary creed of the late Dr. Eliot Coues : 



" Every offspring tends to take on precisely the structure or 

 form of its parents, as its natural physical heritage ; and the 

 principle involved, or the law of heredity, would, if nothing 

 interfered, keep the descendants perfectly true to the physical 

 characters of their progenitors ; they would breed true and be 

 exactly alike. But counter influences are incessantly operative, 

 in consequence of constantly varying external conditions of 

 environment ; the plasticity of organization of all creatures ren- 

 dering them more or less susceptible of modification by such 

 means, they become tinlike their ancestors in various ways and 

 to different degrees. On a large scale is thus accomplished, 

 by natural selection and other natural agencies, just what man 

 does in a small way in producing and maintaining different 

 breeds of domestic animals." 1 



It should be needless to say that this formula, like many 

 statements of similar import which might be collected from 

 biologists of a former generation, and even from those of the 

 present day, involves a complete misrepresentation of the facts. 

 No such species has been found in nature, and no species has 

 been made uniform by an}' refinement of artificial conditions. 

 It is possible through selective inbreeding to eliminate a large 

 part of the normal individual diversity of organisms, but at the 



'The Popular Science Monthly, May, 1903. 



