The Biology of Senescence 



of Notes and Queries, and Young (1899) devoted much time to 

 exposing the pretensions of past supercentenarians. In some of 

 the 'documented' cases, the life-span of father, son, and grandson 

 of the same names were apparently conjoined in one record. 

 Young's greatest authenticated record was a few weeks short 

 of 1 1 1 years. 



The actuarial probability of an individual's exceeding the 

 age of 150 years, on the life-data of 1939, has been estimated 

 at (J) 50 (Greenwood and Irwin, 1939). Putter (1921) calculated 

 on a basis of German vital statistics for the years 1871-91 that 

 ages over 105 were effectively impossible, and that for every 

 million persons reaching 20 years, the number reaching 109 

 would be 4-8 x 10 -10 : 'danach ware es nunmehr wohl an der 

 Zeit, die Berichte iiber 120, 130, 140, 150 usw.-jahrige dahin zu 

 verweisen, wohin sie gehoren: ins Reich der FabeP. This 

 scepticism has proved excessive, especially as regards the popu- 

 lation-frequency of centenarians (see Freudenberg, 1949). The 

 existence of supercentenarians cannot be disproved by statistical 

 means unless the distribution of ages is really continuous, since 

 ordinary life- tables have no defence against, say, a rare geno- 

 type with double the normal potential life-span. The number 

 of persons reaching 100 years is in any event too small for 

 statistically significant estimates of the rate of increase in the 

 force of mortality after about 90 years of age. Putter's estimate 

 was based on the assumption that this increase continued at the 

 same rate as in earlier life. The relation between observation 

 and calculation in this part of the life-table is fully discussed 

 by Greenwood and Irwin (1939). 



Subsequent writers have been content to rely on direct 

 observation, provided that only records supported by proper 

 documentary evidence are taken seriously (Forster, 1945; 

 Tomilin, 1938). The minimum requirements are these laid 

 down by Thorns (1873) — documentary evidence of birth (or 

 baptism), of death or present age, and of identity. The third of 

 these, as Pearl (1928) points out, is commonly the key to false 

 records of extreme age. The best of such evidence, from com- 

 pulsory birth certification, has been available in England since 

 1837, and would now be available for records up to 118 years 

 (1955). By critical standards of comparable severity the greatest 



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