Tidal Volume

Nine things in this book breathe. Twelve only look as though they do. One is left open.A lung. A heart. A star that swells and shrinks on a clock of five days and nine hours. A tide. The northern hemisphere of this planet, breathing once a year, on a chart kept from a mountain in the Pacific since 1958.Against them: a fire, a bellows, a cave that inhales when the weather turns, a loaf of bread, a two-thousand-year-old blown bottle holding the shape of one exhalation, a whistled language crossing two kilometers of valley, and the universe itself.The difference is a rule with two clauses. A thing breathes if it runs a two-phase cycle in which one phase is paid for and the other returns free out of a store, and if running that cycle spends something it cannot get back. The rule is stated in the first chapter and applied in the open to everything after it, with every verdict argued on the page.Four of the twenty-two went against the answer the author wanted. They are printed anyway, along with the two occasions when the rule itself had to be rebuilt because a case would not sit still.The book moves from a newborn's first breath to Virginia Apgar's scoring system, from the Copenhagen polio epidemic that invented the intensive care unit to the machine at a bedside now, from Cepheid variables to the Keeling curve, from the invention of glassblowing to a Turkish valley where people speak in whistles. It ends at the boundary where medicine decides a person has stopped.With an appendix setting out all twenty-two verdicts, a glossary, a bibliography of 119 sources, twenty questions for discussion, and a full index.