3 o8 THE TREND OF THE RACE 



may take comfort in the fact that their claims to superiority 

 are not without their champions. Indeed some of the papers of 

 which Pearson is a joint author suggest that in some respects the 

 first born may have an advantage over their successors. Beeton 

 and Pearson in their investigation of the age at death of over 

 i, ooo pairs of sisters and brothers found that the earlier born had 

 on the average a longer life. The ages at death were as follows: 



Elder Younger 



Sisters 59-9 2 4 55-66; 



Brothers 5 8 -5 6 o 54-575 



The study was based on the longevity of adults who have 

 reached maturity, thus eliminating the effect of infant or child 

 mortality. In a study of 1,051 pairs of brothers and 733 pairs 

 of sisters where it was possible to ascertain the interval between 

 the births it was found that the greater the interval the less 

 is the expectation of life of the younger member of a pair. "A 

 brother born ten years before another brother has probably 

 seven years greater duration of life; a sister born ten years before 

 another sister has about six years longer duration of life." 



This conclusion is not exactly opposed, however, to the doctrine 

 of the inferiority of the first born, especially at birth. As only 

 adults were considered in Beeton and Pearson's studies the 

 earlier born had passed the first ordeals of life and their greater 

 early death rate may have rendered them relatively more hardy 

 than their less stringently selected younger siblings. 



In an article entitled "The Long-Lived First-Born" the editor 

 of the Journal of Heredity presents a study of longevity accord- 

 ing to birth rank of 802 individuals most of whom were over 90 

 and all of whom were over 80 years of age. A relatively large 

 number, 217 out of 802, or 27.05 per cent of first born children live 

 to be aged; a smaller percentage of aged occur in the second born, 

 118 out of 786, or 15.01 per cent and a still smaller percentage 

 of aged occur in the third born, 104 out of 765, or 13.59 P er cent, 

 the succeeding birth ranks showing only a slight further decrease. 



