Lungs — Breath and Exchange

Take one deep breath in. Pause briefly. Breathe out. What happens here in fractions of a second is the most intimate negotiation your body conducts at all: the outside world becomes the inner world. The inner world becomes the outside world. Oxygen molecules that were just part of a tree, a wind, a sea pass into your blood and become you for a few seconds. Carbon dioxide that has just left your cells returns to the circulation of the world — and tomorrow perhaps nourishes a leaf, a blade of grass, an alga.