In brief, while natural selection has not been established 

 as in any sense an originative process, it has been demon- 

 strated, I believe, as a judicial process. For we may liken 

 the many varied vital conditions to jurymen, before whom 

 every organism must present itself for judgment; and a 

 unanimous verdict of complete or at least partial approval 

 must be rendered, or the organism must perish. 



The phenomena of biological inheritance, however, have 

 demanded the greater attention of Darwinian and post- 

 Darwinian investigators. A complete statement of the 

 whole of evolution must show how species maintain the 

 same general characteristics through inheritance, how the 

 type is held true with passing generations, and it must also 

 show how new characters may enter into the heritage of 

 any species to be transmitted as organisms transform in 

 evolution. 



The earliest naturalists had accepted the fact of inheri- 

 tance as self-sufficient. The resemblance between parent 

 and offspring did not demand an explanation any more 

 than variation. When Buff on, however, added the ele- 

 ment of species transformation, he held that external 

 influences could bring about a directly responsive organic 

 change, which he assumed was inherited. Lamarck devel- 

 oped the well-known view, previously advocated by Eras- 

 mus Darwin, that indirect responses to the environment 

 could be fixed in inheritance as so-called "acquired charac- 

 ters," meaning by this phrase that such characters are 

 acquisitions during the life-time of an individual as the 

 effects of disuse or unusual use, or of new habits. Coming 

 again to Darwin, we find that he endeavored to support 

 Lamarck's doctrine and to supplement his doctrine of 

 selection by adding the theory of pangenesis. According 

 to this every cell of every tissue and organ of the body 

 produces minute particles called gemmules, which partake 

 of the characters of the cells that produce them. The 



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