REPRODUCTION, PUBERTY AND LONGEVITY. 24 1 



uted to use-inheritance, but it can be shown to be fallacious. To 

 do this I again had recourse to the Redfield Genealogy and selected 

 from it every family which had four or more sons who reached 

 maturity and who did not lose their lives because of war or accident. 

 The result of this has been put into the following table : 



Average Life of Different Sons. 

 Eldest Son. Second Son. Third Son. Fourth Son. 

 Years .... 60.85 69.14 69.85 71-14 



Here we find that the average length of life of the fourth sur- 

 viving son is more than ten years greater than the average life of 

 the eldest surviving son. There can be no selection in this case 

 because the different sons of a family are sons of identical parents, 

 and not sons of different and selected parents. Furthermore, we 

 find the results in this case more uniform and more emphatic than 

 in the previous case, and from it we may conclude that selection 

 has no bearing on the matter. 



LONGEVITY AND BIRTH-RANKS OF BROTHERS AND SISTERS. 



To test this matter still further I took some fifteen or twenty 

 different family genealogies and abstracted from them every family 

 in which four or more children lived to become adults. In doing" 

 this I made no discrimination between sons and daughters, but 

 took all that came and tabulated them for birth-ranks and length of 

 life. From 1,104 persons thus selected, and among whom those 

 having high birth-ranks were the brothers and sisters of those 

 having low birth-ranks, it was found that there was a very uniform 

 increase in length of life as birth-ranks grew higher. The ages of 

 the fathers ranged from 19 to 64, and a diagram made from the 

 table showed that for each four years added to the age of the 

 father one year was added to the length of life of the child. I also 



