CONTINUING THE SEARCH FOR A LAW OF MORTALITY

Scientists have long attempted to explain why closely similar age patt erns of death are characteristic of highly diverse human and nonhuman populations. Historical efforts to identify a general ''law of mortali ty'' from these patterns that applied across species ended in 1935 whe n it was declared that such a law did not exist. These early efforts w ere conducted using mortality curves based on all causes of death. The authors predict that if comparisons of mortality are based instead on ''intrinsic'' causes of death (i.e., deaths that reflect the basic bi ology of the organism), then age patterns of mortality consistent with the historical concept of a law might be revealed. Using data on labo ratory animals and humans, they demonstrate that age patterns of intri nsic mortality overlap when graphed on a biologically comparable time scale. These results are consistent with the existence of a law of mor tality following sexual maturity, as originally asserted by Benjamin G ompertz and Raymond Pearl. The societal, medical, and research implica tions of such a law are discussed.