178 



BIOLOGY OF DEATH 



degrading environmental conditions, or economic want 

 can have influenced the results. These data were com- 



30 







> 



20 



15 



10 



MOTHER AND CHILDREN 

 FATHER AND CHILDREN 



16 



36 



56 



66 



\ 



\ 



\ 



\ 



66 and over 



AGE. AT DEATH OF PARENTS 



FIG. 44. Diagram showing the influence of age at death of parents upon the percentage of 



offspring dying under 5 years. (After Ploetz). 



piled by the well-known German eugenist, Professor 

 Ploetz of Munich. The lines show the falling per- 



