Over the course of a day, we generate billions of little canisters of fuel, to fire a billion little engines, in the billions of cells in our bodies. “Should all the billions of gently burning little fires cease to burn,” the physical chemist Eugene Rabinowitch wrote, “no heart could beat, no plant could grow upward defying gravity, no amoeba could swim, no sensation could speed along a nerve, no thought could flash in the human brain.”
