210 DARWINISM TO-DAY. 



successive generations through which the species is safely 

 carried by the temporary regularly appearing ontogenetic 

 adaptations. But there is nothing in strict neo-Darwinism 

 to permit of any such idea of increase. Such moving for- 

 ward without the aid of selection can only be explained by 

 the adoption of some theory of orthogenesis. Either the con- 

 genital variations are of such a character that the resulting 

 ontogenetic modifications are not fairly to be distinguished 

 from them, in which case they are assumed to be large 

 enough from the start to afford handles for natural selection 

 (which the proposers of the theory are not claiming), or 

 they depend for their preservation on a kind of happy coinci- 

 dence in occurrence with similar more effective ontogenetic 

 modifications which are really large enough to save the life 

 of the organism and hence the slight congenital variations 

 along the same line. But in this latter case organic selection 

 cannot demand much discussion until it explains away a 

 Delageand radical failing pointed out clearly by Delage 



Plate's criticisms d pj t Thig j j j th t th face f 

 of organic selec- r ' 



tion, the large character which ontogenetic adapta- 



tion may and often does possess, those individuals in which 

 the slight congenital variations in the right direction finally 

 appear will have no special advantage over those in which 

 they do not appear ; the large and effective character of the 

 ontogenetic adaptations, which are common to both kinds of 

 individuals, being quite sufficient to determine the result of 

 personal selection. The congenital variations will be too 

 small in comparison with the ontogenetic variations to cut 

 any figure in the fate of the individuals, and there is no 

 reason at all to believe that individuals showing the slight 

 congenital variations in the right direction will be the only 

 ones to show the saving large ontogenetic adaptations. 

 Plate suggests the following case to show the inutility of 

 this theory : Suppose an antelope species to have a leg muscle 

 averaging seven cm. in thickness, and several individuals to 



