60 MAN THE ANIMAL 



go out and collect entirely at random every single case possible 

 to find of children dying before they were five years old — 

 extremely short-lived human beings in fact, who were unable 

 to get far in the pleasant business of living either because they 

 were inherently bad biological eggs literally or figuratively, or 

 because they never had a fair chance to live on account of a bad 

 environment associated with parental poverty or ignorance or 

 vice. Now suppose further that we followed the fathers of these 

 poor creatures along through their whole lives and set down 

 in the record their ages at death when they (the fathers) finally 

 died. It would then be possible to construct a life table for 

 the category of Fathers of Persons Dying under 5 Years of Age. 

 Having done all this, suppose we next did precisely the same 

 thing for a group of fathers of persons who did not die until 

 they were eighty years old or more — in other words, a group 

 of old gaffers with demonstrated great powers of living, which 

 powers may conceivably have arisen from their innately superior 

 biological make-up, or from great good luck combined with 

 good sense in their choice of victuals and drink, or from always 

 wearing their rubbers when it rained, and so on through the en- 

 tire list of precepts and superstitions thought to promote lon- 

 gevity. When the data had been collected and the computations 

 made we should then be in possession of a life table for the 

 category of Fathers of Persons Dying at 80 and Over Years of 

 Age. 



How will these two life tables compare with each other? The 

 next figure. Figure 7, shows the answer so far as concerns the 

 expectation of life (or average-after-lifetime) at four selected 

 ages twenty, forty, sixty, and eighty years. 



It is at once evident that, so far as concerns the present ma- 

 terial involving well over a hundred thousand life years ex- 

 posure to risk, the long-lived children had fathers who were 

 much longer-lived than the fathers of short-lived children. 



Corresponding life tables for mothers tell the same sort of 

 story. 



The relative excess in life duration of the parents of long- 



