Your pulse is your life, the ultimate proof you’re animate and have something rare to lose. Everything alive has some kind of flux and ebb, and when that stops, life stops. When people say life is precious, they are saying that the rhythmic force that runs through all things—your wrist, your children’s wrists, God’s entire green earth—is precious. For my whole life, my pulse ran through me with such quiet power that I never had to think about it. And now they were having trouble finding it.