316 THE COMING OF AGE OF [LECT. 



species and of the existence of great breaks, which 

 there was no obvious or probable means of filling up, 

 between various groups of organic beings. 



For various reasons, scientific and unscientific, much 

 had been made of the hiatus between man and the 

 rest of the higher mammalia, and it is no wonder 

 that issue was first joined on this part of the con- 

 troversy. I have no wish to revive past and happily 

 forgotten controversies ; but I must state the simple 

 fact that the distinctions in the cerebral and other 

 characters, which were so hotly affirmed to separate 

 man from all other animals in 1860, have all been 

 demonstrated to be non-existent, and that the con- 

 trary 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." ] 



Adverse criticism made merry over such sugges- 

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



1 "Origin of the Species," p. 431. 



