On Youth And Old Age, On Life And Death, On Breathing

These short treatises, often grouped as the Parva Naturalia, examine the biological and physiological phenomena common to body and soul. The text investigates the stages of life, the processes of waking and sleeping, and the vital function of respiration in maintaining internal heat. Aristotle seeks to explain the mechanism of life preservation and the inevitable decay that leads to death. It is a detailed physiological study that connects the functions of specific organs to the broader cycles of existence.