Variability of the duration of life of living creatures

The life span of man has long occupied human thoughts. All men feel that the duration of life of living creatures is governed by fixed laws. But theologians, philosophers and scientists have failed to find an answer. In this publication the beaten paths of demographers, actuarians and statisticians are abandoned. It is tried to apply the laws of Nature and in particular the laws of physico-chemical equilibrium. For this purpose censuses of many nations and many biological experiments were investigated. It is maintained that the equilibrium between living creatures and their ecosystem is analogous to the equilibrium between living macromolecules and their biochemical environment. The publication presents the De Mortibus distribution as an underlying model for the duration of adult life. This family of distributions has two parameters which depend (1) on the genetic material and (2) on the ecosystem. Examples of humans, thoroughbred racehorses and laboratory animals including the deceleration of old-age mortality in low-mortality populations are given. It is stated that the limit distribution of the family represents the variability of the limits of the duration of life and that it can be used for forecasting the development of mortality in low-mortality populations.