...至（一息六动）曰离经。（适得病）四至（一息八动）曰夺精。（病将甚）五至（一息十动）曰死。（难治）六至（一息十二动）曰命绝。（必死）此至之脉也。何谓损。一呼一至（一息二动）曰离经。再呼一至（一息一动）曰...