John A. Behnke

The Biology of aging

The concept that aging is an endogenous process inherent in all living things and not basically dependent on stress and disease is increasingly accepted, although we still do not have sufficient data to choose finally between these alternatives or to conclude that a cell, organ, or organism placed in an optimal environment may not live indefinitely. Gerontologists with a primary interest in pathology are perhaps more inclined to emphasize disease in relation to aging, but they may be biased, since they commonly see the end-result of illness requiring hospitalization. Certainly pathologists are unlikely to see the few persons who die essentially of uncomplicated old age. The fact that maintenance of various species of animals on a limited diet will prolong life through delaying sexual maturation and prolonging growth still constitutes the strongest support for the view that aging is an endogenous process—a product of reduced growth potential or insufficient rate