《黄帝内经·素问·调经论》
岐伯说：刺治这种疾病应取其经脉，病在营分的刺治其血，病在卫分的刺治其气，同时还要根据病人形体的肥瘦高矮，四时气候的寒热温凉，决定针刺次数的多少，取穴部位的高下。
岐伯曰：刺此者，取之经隧，取血于营，取气于卫，用形哉，因四时多少高下。
Qi Bo replied, "To treat such disease, choose the correct channel. If the disease is in the nutritive level, treat the Blood; if in the defensive level, treat the Qi. As for how many needles should be inserted and how deeply, these depend on the patient's height, weight, and the coldness or warmth of the climate."