in DARWIN'S CONFESSION 139 



true that specific differences, so constant 

 and so definite through enormous periods 

 of time, are incompatible with perpetual 

 instability. Darwin himself spoke of 

 "fixity" as an essential characteristic of 

 true species. He admitted that this 

 fixity is never attained by the human 

 breeder ; and he even admitted that it 

 could only be obtained by "selection 

 with a definite object." 1 This is a most 

 remarkable declaration. Just as we 

 have seen Mr. Spencer, under the in- 

 ducements of controversy, throwing 

 overboard his old demand for enormous 

 periods of time, so now we find Darwin 

 throwing overboard the idea of variations 

 being either constant, or indiscriminate, 

 or accidental, and even insisting that 

 " fixity" in organic forms is an aim in 

 Nature, and can only be secured through 



1 Quoted by Professor Poulton, Charles Darwin^ 

 etc., p. 201. 



