234 THE COMING OF AGE OF vii 



existent, and that the contrary doctrine is now 

 universally accepted and taught. 



But there were other cases in which the wide 

 structural gaps asserted to exist between one group 

 of animals and another were by no means fictitious ; 

 and, when such structural breaks were real, Mr. 

 Darwin could account for them only by supposing 

 that the intermediate forms which once existed 

 had become extinct. In a remarkable passage he 

 says 



" We may thus account even for the distinctness 

 of whole classes from each other for instance, of 

 birds from all other vertebrate animals by the 

 belief that many animal forms of life have been 

 utterly lost, through which the early progenitors 

 of birds were formerly connected with the early 

 progenitors of the other vertebrate classes." l 



Adverse criticism made merry over such sugges- 

 tions as these. Of course it was easy to get out of 

 the difficulty by supposing extinction ; but where 

 was the slightest evidence that such intermediate 

 forms between birds and reptiles as the hypothesis 

 required ever existed ? And then probably followed 

 a tirade upon this terrible forsaking of the paths 

 of " Baconian induction." 



But the progress of knowledge has justified Mr. 



Darwin to an extent which could hardly have 



been anticipated. In 1862, the specimen of 



Archceopteryx, which, until the last two or three 



1 Origin of Species, p. 431. 



