EVIDENCES OF EVOLUTION. 83 



The individual life history of an animal — often strangely 

 circuitous or indirect — is interpretable as a modified re- 

 capitulation of the probable history of the race. The 

 embryo mammal is at one stage somewhat like an embry- 

 onic fish, at another like an embryonic reptile ; even in 

 details the recapitulation, if such we may term it, is some- 

 times faithful. 



Such, in merest outline, is the nature of the evidence 

 which leads us to conclude that the various forms of life 

 have descended or have been evolved from simpler ancestors, 

 and these from still. simpler, and so on, back to the mist of 

 life's beginnings. None of the evidence is logically demon- 

 strative ; we accept the evolution idea because it is a 

 plausible interpretation which is applicable to many orders 

 of facts, and is contradicted by none. 



In accepting the evolutionist interpretation naturalists are 

 unanimous ; but in regard to the manner in which the 

 modification of species or the general ascent of life has 

 been brought about, there is much difference of opinion. 

 The fact of evolution is admitted ; debate goes on with 

 regard to the factors (see Chapter XXIX.). 



