Huangdi said: I wish to hear about the strange and evil conditions that are not mentioned in the classics. Qibo said: The blood collaterals are such. Huangdi said: Why do some people faint when the blood collaterals are pricked? Why does blood shoot out when pricked? Why is the blood dark and turbid? Why is the blood clear and half of it like juice? Why does swelling occur after the needle is removed? Why does the face turn pale whether the blood loss is much or little? Why does the face remain unchanged but the person feels restless after the needle is removed? Why does a lot of blood come out without any movement? I wish to hear the reasons.
Qibo said: When the meridian qi is abundant but the blood is deficient, pricking will cause the qi to collapse, and the collapse of qi will cause fainting. When both blood and qi are abundant and the yin qi is excessive, the blood will be smooth, and pricking will cause it to shoot out. When yang qi accumulates and is not released for a long time, the blood will be dark and turbid, so it cannot shoot out. If one has just drunk and the fluids seep into the collaterals but have not yet mixed with the blood, the blood will come out separately from the juice. If one has not just drunk, there is water in the body, which over time will cause swelling. When yin qi accumulates in the yang and the qi is trapped in the collaterals, pricking will cause the qi to move before the blood comes out, hence causing swelling. When the yin and yang qi have just met but have not yet harmonized, and are thus released, both yin and yang will be depleted, and the exterior and interior will separate, causing the complexion to turn pale. When pricking causes a lot of blood loss, but the complexion does not change and the person feels restless, it is because pricking the collaterals depletes the meridians, and the meridians belong to yin. Prolapse of the uterus causes restlessness. When yin and yang meet and combine to cause blockage, this is due to internal overflow into the meridians and external flow into the collaterals. In such cases, both yin and yang are excessive, and even if a lot of blood is lost, it cannot cause depletion.
Huangdi said: How can one discern this? Qibo said: The blood vessels, when full and firm, appear red and can be found anywhere on the body, small as a needle or large as a tendon. Pricking and releasing them ensures complete safety, so do not lose count. If the count is lost and reversed, each will follow its own measure. Huangdi said: Why does the flesh cling to the needle when it is inserted? Qibo said: Heat is trapped in the needle, making the needle hot, and the heat causes the flesh to cling to the needle, hence it becomes firm.