An Introduction to a Biology 



time seems to be past when one man can even be inter- 

 ested in the whole problem. Evolutionists may be broadly 

 classified into those to whom the problem of evolution is 

 the problem of the origin of species and those to whom it 

 is the problem of adaptation. The keynote of de Vries's 

 " Mutationstheorie " is the solution of the problem of 

 species ; we even go so far as to say that this is the achieve- 

 ment of de Vries's work. The logical conclusion, the com- 

 plete working out of the theory of natural selection, is 

 reached in Dr. Archdall Eeid's " Principles of Heredity." 

 The interest of the two authors is entirely different. De 

 Vries's interest is in the origin of species, Dr. Reid's in natu- 

 ral selection. Darwdn's interest was in both ; if we look 

 no further than the title of his chief work we can see this — 

 " On the Origin of Species by Means of Natural Selection." 



The fact that these two interests have segregated, and 

 the way in which they have segregated, are both very sug- 

 gestive, and the direction in which they point is the same. 

 The fact of segregation suggests that the association of 

 the two ideas was unnatural, and that they were not cap- 

 able of union. The way in which they have segregated con- 

 firms this suspicion. For those who devote their atten- 

 tion to the question of species reject natural selectioi), 

 while those who elaborate the theory of natural selection 

 find no support in the phenomenon of specific difference. 

 All possibility of a reconcilement between the divorced 

 ideas is put an end to by Meyrick, who probably knows 

 more about specific diiierence than anyone else. In his 

 handbook of British Lepidoptera he says that, in seeking 

 for the most suitable characters by which species may be 

 distinguished, those which can in any way be regarded as 

 useful to the species must be discarded without more ado. 



It is not surprising that Darwin's work should have 

 borne fruit which segregated in this way. The case is 

 thoroughly Mendelian. Darmn's work was a cross between 

 a biological theory of evolution and a social and indus- 



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