138 THE PROBLEMS OF EVOLUTION 



view that the full degree of an acquired character 

 is inherited, but many scientists admit the possi- 

 bility that the heritage may be somewhat modified 

 through the influence of individual development. 

 To this extent we may recognize in Lamarck's 

 work a keen appreciation of natural processes, 

 in spite of an admixture of wholly unscientific 

 assumptions, and it is noteworthy that it is more 

 effective than Darwin's work in accounting for 

 the origin of changes in the organism. Lamarck's 

 theory accounts for the origin of variations to 

 the extent of referring them to a universal prop- 

 erty of living matter, but fails to account for 

 their perpetuation in the species; Darwinism ac- 

 counts for the behavior of existing variations but 

 fails completely to account for their origin. Thus 

 the essential difficulty of evolutionary theory in 

 general remains the association of individual de- 

 velopment with the evolution of the species. The 

 inheritance of acquired characters is, as I have 

 said before, an objectionable term, but it indicates 

 in familiar words the major problem of evolution. 



The supporters of Lamarck's views have, in their 

 theoretical work, devoted themselves to the formu- 

 lation of hypotheses to meet this problem. Some 

 have to do with particular phases of environmental 

 influence, others are merely general hypotheses. 



Cope's theory of kinetogenesis has long held a 

 place in the literature of evolution. It assumes, in 



