286 FOOT-NOTES TO EVOLUTION. 
cretin parents. It is strange that self-interest does not 
lead the natives of Aosta to place their cretins under 
such restrictions as would prevent their illicit inter- 
course; and it is still more surprising to find the Catho- 
hie Church actually legalizing their marriage. There is 
Fic. 28.—A cretin of Aosta. (After Whymper.) 
something horribly grotesque in the idea of solemnizing 
the union of a brace of idiots, and, since it is well known 
that the disease is hereditary and develops in successive 
generations, the fact that such marriages are sanctioned 
