APPENDIX. 



I. THE REJECTION OF SELECTION. 



Many years ago Semper^ denied the power of se- 

 lection to create an organ, declaring that the organ 

 must have previously existed before selection could 

 have increased and developed it. More recently 

 Wolff'' has distinguished himself by the vigor with 

 which he has attacked the "task" of "setting aside the 

 dogma of selection." Henry B. Orr' is also of opinion 

 that selection is not the real cause of improved organic 

 states; he regards it as a factor checking growth in 

 certain directions, but not as a cause producing growth. 

 Likewise Yves Delage,* in his recent voluminous but 

 in many respects excellent work, regards natural selec- 

 tion solely as a subordinate principle which is devoid 

 of all power to create species (p. 391), although he 

 grants to it certain functions, and even characterises it 



1 Semper, Die natiirlichen Existemhedingungen der Thiere, 

 Leipsic, 1880, pp. 218-219. 



^Wolflf, "Beitrage zur Kritik dex Darwin'schen Lehre," 

 Biolog. Centralblatt, Vol. X., Sept. 15, 1890, and "Bemerkungen 

 zum Darwinismus mit einem experimentellen Beitrag zur 

 Physiologie , der Entwicklung,'' Biolog. Centralblatt, Vol. 

 XIV., Sept. I, 1894. 



s Henry B. Orr, A Theory of Development and Heredity, 

 New York, 1893. 



* Yves Delage, La structure du protoplasma et les theories 

 sur I'heredite et les grands problemes de la biologie generale, 



Paris, 1895. 



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