A GENERATION'S PROGRESS IN THE STUDY 

 OF EVOLUTION ' 



By Edwin G. Conklin 



If one were searching for the most inclusive subject in modern 

 scientific research, what other topic would touch so many fields 

 as that of evolution? In the nonliving world it includes almost 

 everything from the evolution of atoms to that of universes; in the 

 living world practically everything from amoeba to man, from germ 

 cells to developed organisms, from reflexes to reason, from savagery 

 to civilization. Almost all the work of modern science and learning 

 could be classified under some of these fields. The small part of this 

 vast theme which I shall touch upon in this address concerns merely 

 some of the recent work on the methods and causes of organic 

 evolution. 



Thirty-eight years ago I, a newcomer to Philadelphia, was intro- 

 duced to the American Philosophical Society as one of the speakers 

 in a symposium on " The Factors of Organic Evolution." The 

 symposium occurred on the evening of May 1, 1896, the speakers 

 being Prof. Edward D, Cope, Prof. Liberty H. Bailey, of Cornell 

 University, and myself, and since our addresses represented fairly 

 well the methods and conclusions of students of evolution a genera- 

 tion ago, I will briefly state a few of their principal conclusions. 

 Cope - maintained the Lamarckian point of view that variations are 

 the materials of evolution and that they are caused (1) by the direct 

 action of the environment on developed organisms (his physiogenesis) , 

 (2) by the inherited effects of use or disuse (his kinetogenesis)", (3) 

 by the energy of growth forces (his bathmogenesis) and (4) by sen- 

 sations or consciousness (his archaesthetism). It was characteristic 

 of Cope and of many other naturalists of a generation ago that they 

 assumed the existence of certain principles of evolution which 



* Penrose Memorial Lecture, read Apr. 20, 1934. Reprinted with slight alterations, by 

 permission, from Proceedings American Philosophical Society, vol. 74, no. 1, 1934. 



' He declined to furnish manuscript for publication but his views were fully expressed 

 in his book The Primary Factors of Organic Evolution, which had just been published. 



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