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

Grouping several short investigations, this text explores the essential physiological functions that sustain life, such as breathing and the regulation of body heat. Aristotle connects the stages of youth and old age to the strength of the vital fire within the heart, viewing death as the eventual extinguishing of this internal heat. The work also considers the phenomena of sleep and dreams as byproducts of sensory processes. It provides a detailed biological account of the life cycle and the maintenance of the living organism.