Summary:

One of the short treatises that make up Aristotle's Parva Naturalia. In comparison to the first five treatises of the Parva Naturalia, this one (and On Length and Shortness of Life), while still dealing with natural phenomena involving the body and the soul, are "definitely biological rather than psychological." The title On Youth And Old Age, On Life And Death, On Breathing, given in the Medieval manuscripts, derives from the treatise's opening words: "We must now treat of youth and old age and life and death. We must probably also at the same time state the causes of respiration as well, since in some cases living and the reverse depend on this."