A Problem in Age-Distribution

The age-distribution in a population is more or less variable. Its possible fluctuations are not, however, unlimited. Certain age-distributions will practically never occur; and even if we were by arbitrary interference to impress some extremely unusual form upon the age-distribution of an isolated population, in time the “irregularities” would no doubt become smoothed over. It seems therefore that there must be a limiting “stable” type about which the actual distribution varies, and towards which it tends to return if through any agency disturbed therefrom. It was shown on a former occasion1 how to calculate the “fixed” age-distribution, which, if once established, will (under constant conditions) maintain itself.