126 THE PROBLEMS OF EVOLUTION 



the value of natural selection itself. He shows 

 that the destruction of most animals after birth 

 occurs during early stages of development or 

 vulnerable stages of metamorphosis and is acci- 

 dental, giving no opportunity for the operation 

 of slight advantages accruing to the individual 

 through the variation of specific structures. He 

 bases another criticism on the fact that organisms 

 meet the exigencies of environmental contact 

 through physiological rather than morphological 

 variations, but this is a less valuable point, since 

 processes are always the expression of structures. 

 The total value of his criticism is tempered by the 

 pronounced teleology of the statement: '*Tout se 

 passe comme si la Nature, voulant la perpetuation et 

 I'extension de la Vie, donnait avant tout une prime 

 a la fecondite et suscitait a I'interieur de Tespece 

 des preadaptations en divers sens qui, aux moments 

 de crise, sauvent I'espece ou etendent son aire." ^ 



Regardless of the possible w^eakness of some of 

 the points in selection and isolation, we must 

 admit their probable potency, but even then we 

 find that they have failed to establish an evolu- 

 tionary process capable of transcending the original 

 limitations of species. They may break a species 

 up or they may gradually lessen the extent of its 

 variations, but they may not change it otherwise. 

 The progress of evolution demands inevitably the 



^ Oy. dt.t p. 90. 



