Longevity 185 



The third column reduces the actual deaths 

 to percentages, and the fourth column gives 

 the normal percentages of births at the cor- 

 responding ages of fathers. The last column 

 gives quotients arising from dividing the 

 percentages in the third column by those in 

 the fourth column, and represents the relative 

 infant mortality at different ages of fathers. 

 Thus, if in a given community, the total 

 infant mortality were 20 per cent, of the total 

 births, those occurring among the children of 

 fathers less than 26 would be only 75.5 per 

 cent, of this 20 per cent., or 16 per cent, in all; 

 while those occurring among the children of 

 fathers over 46 would be 200 per cent, of the 

 20 per cent., or 40 per cent, in all. Or, stated 

 in another way, the relative deaths among 

 the children of the older parents are nearly 

 three times as numerous as among those of 

 the younger parents. Taking the tables for 

 longevity and for infant mortality together, 

 it will be seen that the children of young 

 parents are more likely to survive to matur- 

 ity than the children of old parents, but of 



