Senescence and Senility

Abstract

NEEDHAM¹ has recently claimed that Minot's paradox²: “Senescence is at its maximum in the very young stages and the rate of senescence diminishes with age”, is false. Instead of the relationship Ṡ = Ġ (where Ṡ = rate of senescence, Ġ = specific growth-rate) indicated by Minot he advocates the use of the relationship Ṡ = k/Ġ in which, however, Ġ refers to growth “in the broadest sense .... perhaps in fact anabolism in toto”. It will be argued here that Minot's paradox is derived correctly from the simplest model of a living system; and that Needham's relationship gives only an approximation to the increase in senility in a more complex model. Secondly, it will be suggested that the changes under discussion bear no direct relationship to the rates of anabolism and catabolism at any time, and that changes in senescent systems are not related to changes in specific growth-rates.