HUMAN LONGEVITY 55 



In 1934 my daughter and I published a rather extensive and 

 detailed analysis of 365 of these cases of proven extreme lon- 

 gevity. For each of these cases the ages at death of the six im- 

 mediate ancestors (two parents and four grandparents) were 

 known and recorded, as well as a great many other things about 

 the person and the ancestors. As an example, the pedigree of 

 one of these highly longevous persons is shown in Figure 4. 



In this pedigree the person under discussion (the propositus) 

 is indicated by a solid sex sign. Figures within the circles of the 

 sex signs indicate the ages at death in years, except where there 

 is an L above the age figure, which means that the person was 

 living at the time of record, and at the indicated age in years. 



At the top of the chart the mysterious word TIAL is merely 

 an abbreviation for "total immediate ancestral longevity," 

 and is used to designate the sum of the ages at death of the 

 parents and grandparents. Thus in the present case 104 + 98 + 

 106 + 93 + 97 + 101 = 599 years. It is safe to say that few 

 human beings have ever had an authentic TIAL number higher 

 than this. 



But how much lower are the TIALS of ordinary people, 

 just "run-of-mine" folk who do not themselves live, on the 

 average, longer than the average of the general population? 

 To get an approximate answer to this question, and to have a 

 group to compare with the highly longevous group of non- 

 agenarians and centenarians we assembled, entirely at random 

 so far as concerned their own ages, a group of 136 living persons 

 all six of whose immediate ancestors (parents and grandparents) 

 were dead at the time of observation, and for each of whom 

 the age at death was known and recorded. This seems as fair 

 a group for comparing TIALs with the longevous group as it 

 is humanly possible to get. This comparison group had an av- 

 erage living age of 48.75 years, and contained 29 persons over 

 60 at the time of observation, 6 over 70, and 1 over 80. The 

 average age of the group was almost 1 6 years higher than that 

 of the living white population of the United States in 1930. 



How does the ancestral longevity of this group of ordinary 



