258 MARRIAGE AND DISEASE. 



have all these and other imperfections in common, 

 there are many points of difference which, if not of 

 very great practical importance, are deeply interesting. 

 Let us briefly consider some of these. 



In the first place, although early death is much 

 more common among both these classes than among 

 ordinary children, there is not the same terrible 

 mortality during the first year of life among the 

 children of the senile that occurs in those of the 

 immature. A much larger proportion of the former 

 live to years of maturity, although they seldom or 

 never reach old age. Indeed, they may be said to 

 be old from their birth, for they have many of the 

 characteristics of the aged while still children. 

 Prosper Lucas* and other writers have given some 

 remarkable descriptions of the aged aspect of such 

 children. 



Another most interesting and curious difference 

 is, that whereas both are specially prone to mental 

 imperfection, the insanity or mental distortion does 

 not take the same form with equal frequency in 

 the two classes. Thus among the offspring of the 

 immature, we find blank idiocy very much more 

 common than among that of senile parentage. Among 

 the latter, congenital mental defect is very common 

 also, but it does not nearly so often take the form 

 of utter vacuity as it does in the former. In the 

 one case you generally find blank idiocy, accompanied, 

 it may be, with deaf-mutism, blindness, epilepsy, or 



* " Trait^ philosophique et physiologic^ de l'H6r6dit6 naturelL" 



