RT Journal
T1 THe span of human life
JF JAMA
JO JAMA
YR 2009
FD October 28
VO 302
IS 16
SP 1817
OP 1817
DO 10.1001/jama.2009.1391
UL http://dx.doi.org/10.1001/jama.2009.1391
AB 
There seems to be no reason for supposing that within historical times man's natural term of life has materially varied. Like that of the dog or the horse, it is determined by unknown biologic causes. While some statements in old documents might be taken to indicate that in antiquity men lived hundreds and even thousands of years, such assertions appear to be based on wrong interpretations of time-units or on pure fable. It has been alleged that a larger proportion of persons lived to reach the age of 100 years at certain earlier periods than at the present day, but this belief rests on an equally insecure footing. As is well known, the investigation of alleged instances of centenarianism has shown that many of these cases will not stand examination and that some even are examples of deliberate fraud supported by such devices as the substitution of birth certificates.