Seventy-Ninth Difficulty

The medical classic says: "To meet the onset of pathogenic qi and drain it away—how could this not make a deficient condition even more deficient? To follow the departure of channel qi and supplement it—how could this not make an excess condition even more excessive? The relationship between deficiency and excess is like gaining something and yet losing something; the relationship between excess and deficiency is like existing and yet not existing." What does this refer to?

Answer: To meet the onset of pathogenic qi and drain it away is to drain its child point; to follow the departure of channel qi and supplement it is to supplement its mother point. For instance, if the heart is diseased, drain the Shu-stream point (Daling) of the Pericardium Channel of Hand Jueyin—this is called "meeting and seizing." Supplement the Well point (Zhongchong) of the Pericardium Channel of Hand Jueyin—this is called "following and aiding." What is meant by "excess and deficiency" refers to the firmness and softness of the pulse condition. When the pulse qi arrives firm and solid, it is called "gain"; when the pulse qi arrives soft and weak, it is called "loss." Hence it is said "as if gaining, as if losing."