lO HEREDITY AND CHRISTIAN PROBLEMS 



and his sons and grandchildren, which I will 

 mention again, where the conflict between the 

 tendency to return to the normal type and the 

 tendency toward reproduction is plainly discern- 

 ible. Besides these the following apparent ex- 

 ceptions to our law have been noted. Pericles 

 had two imbeciles and one maniac in his family. 

 Thucydides was the father of a fool and a block- 

 head. The great Germanicus was the father of 

 Caligula, Vespasian of Domitian, and Marcus 

 Aurelius of Commodus. "And," says Lucas, "in 

 modern history it is enough to mention the sons 

 of Henry IV., Louis XIV., and of Cromwell." 



Concerning all exceptions to the law of hered- 

 ity there are two theories : (i) That of Lucas, 

 who holds that " the biologic fact of generation 

 is governed by two laws, — one of spontaneity, 

 the other of heredity." (2) That of Ribot, who 

 maintains that "the causes of spontaneity are 

 only accidental ; it is never more than a chance, 

 the result of the fortuitous play and concurrence 

 of natural laws ; but it is not the effect of any 

 distinct and special law. On this theory there 

 would be one law of heredity with its excep- 

 tions, not two laws, the one of heredity, the 

 other of spontaneity."^ 



^ Heredity, Ribot, p. 199. 



