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  ANNUAL 
  BEPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  president 
  of 
  the 
  British 
  Institute 
  of 
  Actuaries, 
  reached 
  similar 
  con- 
  

   clusions. 
  In 
  his 
  book 
  On 
  Centenarians 
  (17), 
  he 
  found 
  only 
  22 
  indis- 
  

   putable 
  examples 
  of 
  centenarians 
  with 
  ages 
  ranging 
  to 
  upwards 
  of 
  

   105, 
  although 
  in 
  a 
  later 
  edition 
  he 
  was 
  able 
  to 
  increase 
  the 
  number 
  to 
  

   30 
  and 
  the 
  limit 
  to 
  111. 
  

  

  jMost 
  alleged 
  cases 
  are 
  simply 
  exaggerations, 
  or 
  errors. 
  For 
  in- 
  

   stance, 
  the 
  Countess 
  of 
  Desmond 
  is 
  said 
  to 
  have 
  lived 
  140 
  years, 
  owing 
  

   to 
  a 
  confusion 
  of 
  two 
  persons 
  of 
  the 
  same 
  name, 
  an 
  earlier 
  and 
  a 
  

   later 
  countess. 
  The 
  140 
  years 
  was 
  apparently 
  the 
  interval 
  between 
  

   the 
  birth 
  of 
  the 
  earlier 
  and 
  the 
  death 
  of 
  the 
  later. 
  

  

  Dublin, 
  in 
  his 
  conservative 
  forecast, 
  does 
  not 
  allow 
  for 
  any 
  im- 
  

   provement 
  in 
  mortality 
  after 
  the 
  age 
  of 
  70 
  years. 
  In 
  England, 
  in 
  

   the 
  middle 
  of 
  the 
  eighteenth 
  century, 
  the 
  expectation 
  of 
  life 
  after 
  

   the 
  age 
  of 
  45 
  was 
  rather 
  better 
  than 
  to-day. 
  Halley's 
  life 
  table 
  for 
  

   1687-1691 
  showed 
  an 
  expectation 
  of 
  life 
  after 
  age 
  80 
  greater 
  than 
  

   to-day's 
  although, 
  as 
  Pearl 
  (18) 
  points 
  out^ 
  the 
  data 
  are 
  too 
  scanty 
  to 
  

   make 
  the 
  result 
  significant. 
  

  

  In 
  ancient 
  Egypt, 
  2,000 
  years 
  ago, 
  according 
  to 
  Karl 
  Pearson, 
  

   though 
  the 
  average 
  life 
  lasted 
  only 
  30 
  years, 
  after 
  about 
  age 
  68 
  

   the 
  expectation 
  of 
  life 
  was 
  greater 
  than 
  ours, 
  owing 
  presumably 
  to 
  

   natural 
  selection. 
  

  

  When 
  confronts 
  with 
  these 
  stubborn 
  facts 
  we 
  must 
  confess 
  that 
  

   the 
  problem 
  of 
  extending 
  the 
  limit 
  of 
  human 
  life 
  beyond 
  100 
  years 
  is 
  

   not 
  an 
  easy 
  one. 
  But 
  I 
  believe 
  the 
  100-year 
  limit 
  is 
  a 
  bogey 
  which 
  

   can, 
  and 
  some 
  day 
  will, 
  be 
  beaten. 
  

  

  There 
  are 
  five 
  lines 
  of 
  evidence 
  which, 
  taken 
  together, 
  seem 
  to 
  be 
  

   fairly 
  conclusive 
  that 
  the 
  possible 
  life 
  span 
  of 
  man 
  is 
  much 
  more 
  than 
  

   the 
  century 
  which 
  life-insurance 
  experience 
  seems 
  to 
  indicate. 
  

  

  WHAT 
  ACTUARIAL 
  SCIENCE 
  INDICATES 
  

  

  The 
  first 
  line 
  of 
  evidence 
  is 
  derived 
  from 
  the 
  very 
  tables 
  on 
  which 
  

   actuaries 
  rely, 
  although 
  it 
  seems 
  never 
  to 
  have 
  been 
  noted. 
  If 
  we 
  

   examine 
  the 
  " 
  force 
  of 
  mortality 
  " 
  year 
  by 
  year, 
  we 
  find 
  that 
  after 
  the 
  

   age 
  of 
  60 
  years, 
  while 
  this 
  mortality 
  continues 
  to 
  increase, 
  its 
  rate 
  of 
  

   increase 
  does 
  not. 
  Instead 
  it 
  remains 
  almost 
  exactly 
  constant 
  until 
  

   the 
  age 
  of 
  85, 
  after 
  which 
  it 
  actually 
  decreases, 
  especially 
  for 
  

   females. 
  Figure 
  4 
  shows 
  this. 
  

  

  The 
  studies 
  of 
  Westergaard 
  for 
  centenarians 
  confirms 
  this 
  slowing 
  

   down 
  of 
  the 
  acceleration. 
  He 
  even 
  found 
  (20) 
  in 
  Norway 
  that 
  while 
  

   nonogenarians 
  had 
  one 
  chance 
  in 
  three 
  of 
  dying 
  within 
  a 
  year, 
  cen- 
  

   tenarians 
  had 
  only 
  one 
  chance 
  in 
  four. 
  Now, 
  if 
  there 
  exists 
  any 
  defi- 
  

   nite 
  limit 
  to 
  human 
  life 
  the 
  situation 
  ought 
  to 
  be 
  the 
  reverse. 
  The 
  

   force 
  of 
  mortality 
  ought 
  to 
  grow 
  heavier 
  and 
  heavier 
  and 
  the 
  curve 
  

   representing 
  it 
  ought 
  to 
  bend, 
  not 
  toward 
  the 
  horizontal, 
  but 
  toward 
  

  

  