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THE AMEBIC AX NATURALIST [Vol. XL VI 



transferred from one strain or species to another. It 

 has been shown that the unit characters are much more 

 numerous and finer things than we had thought and, 

 therefore, that the steps of evolution are frequently very 

 small ones and are taking place in many directions. It 

 has shown the relative unimportance of the isolation fac- 

 tor, since true blends of characters rarely, if ever, occur. 

 It has demonstrated the lack of influence by soma upon 

 germ-plasm; but has rendered it probable that external 

 conditions may directly modify the determiners of the 

 germ-plasm. It brings support for the view of selective 

 elimination of undesirable traits but finds that many, if 

 not most, characters that arise are neutral in respect to 

 any adaptive significance. Finally, it looks forward with 

 a justifiable expectancy to the completer experimental 

 test of the factors of evolution and their eventual com- 

 plete elucidation. 



LITERATURE CITED 

 Bormans, A. de, and Kraus, H. 1900. Forficulidse and Hemimeridae. Das 



Tierreich, 11 Lief. Berlin. 

 Castle, W. E., and Phillips, J. C. 1911. On Germinal Transplantation in 



Vertebrates. Carnegie Institution of Washington, Publication No. 144. 

 Davenport, C. B. 1909. Inheritance of Characteristics in Domestic Fowl. 



Carnegie Institution of Washington, Publication No. 121. 

 Davenport, C. B. 1911. The Transplantation of Ovaries in Chickens. 



Journal of Morphology, 22: 111-122. 



