PSYCHIC ADAPTATION 111 



because they first deteriorated in their cerebral 

 organisation, through adopting conditions contrary 

 to a good and normal civilisation, not through being 

 a consequence of this. 



Civilisations decay owing to the changes that the 

 brain undergoes, because men violate the normal 

 conditions of life. 



Kenan, speaking of the invasion of the Roman 

 Empire by the barbarians, says : 



" I believe that if the Empire had had in the fifth 

 century the great men of the second century, and, 

 above all, that if Christianity had been more 

 centralised in Rome, as it became in the centuries 

 that followed, it would have been possible to 

 convert the barbarians to Roman civilisation before 

 or at the time of the invasion, and thus the 

 continuity of civilisation would have been preserved. 

 It was quite within the bounds of possibility for the 

 Middle Ages never to have existed, and the civilisa- 

 tion of Rome to have continued uninterrupted. If 

 the Gallo-Roman schools had been sufficient in one 

 century to educate the Franks, humanity would 

 have saved ten centuries." 1 



The continual wars, the licence of Roman 

 manners, were changing and debilitating the 

 citizens ; their brains were becoming disorganised, 

 and on the arrival of the barbarians it was not 



1 Renan, Avenir de la Science, p. 391. 



