  Author's early work on aging is developed to yield a relationship between
life spans and the velocity of aging. The mathematical analysis shows that the
mean extent of the advancement of aging throughout one's life is conserved, or
equivalently, the product of the mean life span, and the mean rate of aging is
constant. The result is in harmony with our experiences: It accounts for the
unlimited replicability of tumor cells, and predicts the prolonged life spans
of hibernating hamsters, in accordance with the Lyman and coworkers experiment.
Comparing the present result and the empirical relationship between life spans
of various mammals and basal metabolic rates, it is suggested that the mean
rate of aging is intimately connected with the mean basal metabolic rate. With
the help of this information, we inquire the reason of the difference in mean
life spans between women and men, the result showing that the relative mean
life span of women to men is 1 08, for various nations, which is close to the
corresponding relative value of the basal metabolic rate. The present theory
suggests, however, that this relationship between life spans and basal
metabolic rates must be treated with caution.

Populations and Evolution;Quantitative Methods