《黄帝内经·素问·三部九候论》
其脉象忽疏、忽数、忽迟、忽急，一天中如四季之气温交换的时候死亡；若形坏肉脱，虽九候协调，犹是死亡的征象；假使七诊之脉虽然出现，而九候都顺于四时的，就不一定是死候。
其脉乍疏乍数乍迟乍疾者，日乘四季死。形肉已脱，九候虽调犹死。七诊虽见，九候皆从者不死。
The pulse image is sometimes sparse, sometimes rapid, sometimes slow, and sometimes urgent. One will die when the temperature changes like the four seasons in a day. If the body is damaged and the flesh falls off, even if the Nine Periods are in harmony, it is still a sign of death. If the pulse of the Seven Examinations appears, but the Nine Periods are all in accordance with the four seasons, it is not necessarily a sign of death.