Huangdi said: You mentioned that the pathogenic factors of thief-wind and evil-qi injure the human body, causing disease. Now, some people do not leave their shelters nor exit their rooms, yet they suddenly fall ill. This is not because they failed to avoid thief-wind and evil-qi; what is the reason? Qibo replied: These cases are all due to previous injuries from dampness (Shi Qi), which has been stored within the blood vessels and between the muscle layers, lingering for a long time without dispersing. Or perhaps there was a previous fall or injury, leaving stagnant blood (E Xue) inside that was not expelled. Additionally, sudden unregulated joy or anger, improper diet, and irregular exposure to cold and heat cause the interstices (Cou Li) to close and become obstructed. When the interstices open and encounter wind-cold, the blood and qi coagulate, attacking each other with the pre-existing pathogen, resulting in Cold Bi syndrome (Han Bi). If there is heat, sweat will be produced; upon sweating, one becomes susceptible to wind. Even without encountering thief-wind and evil-qi, the disease must inevitably manifest due to the addition of new factors triggering the old pathogens. Huangdi said: What you have described so far are matters known to patients themselves. For those who have not encountered external pathogens, nor experienced fright or anxiety, yet suddenly fall ill, what is the cause? Is it solely due to events involving spirits and ghosts? Qibo replied: This is also because old pathogens remain latent within the body without manifesting. Subsequently, emotional aversion or desire causes internal disorder of blood and qi, where two types of qi clash. The origin of these pathogens is subtle; they cannot be seen or heard, thus appearing as if caused by spirits and ghosts. Huangdi asked: Regarding diseases cured by Zhu You (incantation therapy), what is the reason? Qibo replied: Ancient shamans understood the mutual overcoming of the hundred diseases and knew beforehand the origins of the illnesses; therefore, they could be cured through Zhu You.

Huangdi asked: Do women lack hair on the face because they lack blood and qi? Qibo answered: The Chong Mai (Penetrating Vessel) and Ren Mai (Conception Vessel) both originate from the Bao Zhong (Uterus/Cavity Center), ascend along the interior of the back, and serve as the Sea of the Meridians. Their branches that float outward follow the abdomen upward, converge at the throat, and branch off to connect with the lips and mouth. Abundant blood and qi fill the skin and warm the flesh; when blood is particularly abundant, it渗ates into the skin, generating fine hair. Women are born with an excess of qi but a deficiency of blood, primarily due to frequent blood loss (such as menstruation and childbirth). Since the Chong and Ren meridians fail to nourish the lips and mouth, facial hair does not grow. Huangdi further asked: If a scholar suffers injury to his yin organ, leading to the severance of yin qi, inability to erect, and loss of sexual function, yet his beard remains, what is the reason? Why do eunuchs lack even a beard? I wish to hear the explanation. Qibo replied: Eunuchs have their Zong Jin (external genitalia) removed, injuring the Chong Mai. Blood is lost and fails to recover, internal结uration occurs in the skin, and the lips and mouth are not nourished; thus, facial hair does not grow. Huangdi asked: There are those called Tian Huan (heavenly eunuchs/congenital absence of secondary sexual characteristics) who have never suffered trauma or blood loss, yet they also lack facial hair. What is the reason? Qibo replied: This is due to congenital insufficiency. Their Ren and Chong meridians are not vigorous, the Zong Jin fails to develop properly, there is qi but no sufficient blood, and the lips and mouth are not nourished; hence, facial hair does not grow. Huangdi exclaimed: How profound! The sage comprehends all things, just as the sun and moon cast shadows and sound produces echoes; hearing the sound reveals the form. Without you, who could elucidate the subtleties of all things so clearly? Therefore, sages observe complexion: yellow and red complexions indicate abundant heat qi; blue and white complexions indicate deficient heat qi; black complexions indicate abundant blood and deficient qi. Those with beautiful eyebrows have abundant blood in the Tai Yang channel; those with sideburns extending to the temples have abundant blood in the Shao Yang channel; those with full beards have abundant blood in the Yang Ming channel. This is the general rule. According to the constant laws of the human body, the Tai Yang channel typically has abundant blood and deficient qi; the Shao Yang channel typically has abundant qi and deficient blood; the Yang Ming channel typically has abundant blood and abundant qi; the Jue Yin channel typically has abundant qi and deficient blood; the Shao Yin channel typically has abundant blood and deficient qi; the Tai Yin channel typically has abundant blood and deficient qi. These are the natural constants.