258 CAUSES OF DEGENERATIVE EVOLUTION 



and then the degenerative evolution of useless insti- 

 tutions is brought about in a similar way as that 

 of non-functional organs. Atrophy of this kind may 

 be, as in biology, either accidental or normal. 1 



In a besieged town cut off from all outside com- 

 munication, all train service is necessarily stopped 

 and the railway staff rendered useless. On the 

 other hand, the defence of the city requires both 

 men and money. Under these circumstances the 

 resources of the railway naturally come to be 

 absorbed in the service of the defence. 



As a good example of normal atrophy may be 

 mentioned the disappearance, at a certain point 



1 See Durckheim on the difference between normal and acci- 

 dental sociological phenomena in Les Regies de la mtthode 



"All sociological phenomena, like biological phenomena, are 

 liable, while remaining the same individuals, to revert to 

 different forms. Now, of these forms, there are two kinds of 

 reversion : 



"The one is common to the whole species, and is to be found, 

 if not in each individual, at least in the greater part of them. 

 The cases are not always identical, varying slightly with the 

 individual, but individual variation is restricted to very narrow 

 limits. 



"The other kind of reversion is exceptional, being of a nature 

 rarely met with, and, when occurring, is seldom permanent 

 throughout the life of the individual. Cases of this kind are excep- 

 tional in point of duration as in other respects. 



' ' Here then are two distinct varieties of phenomena which 

 should be distinguished from one another by different terms. 

 Individuals exhibiting only common characters are called 'nor- 

 mal,' while those exhibiting exceptional characters are designated 

 as ' morbid ' or ' pathological. ' " 



