Cold Hands and Cold Feet — What Illness Is It? In What Season Does Liver Disease Get Better, and When Is It Most Dangerous? Several Days of Constipation — Deficiency or Excess? Doctor Luo Dalun Presents Doctor Ni Haixia’s Thirty-Seventh Lecture on the Huang Di Nei Jing: The Tong Ping Xu Shi Lun — When Evil Qi Is Abundant There Is Excess, When Essence Qi Is Robbed There Is Deficiency; a Deficient Lung and Cold Feet; Out of Season You Live, in Season You Die; Using the Heavenly Stems and Earthly Branches to Judge Life and Death; Warming Yang Rather Than Nourishing Yin; Yin Excess and the Whole Body Swelling Full

Patient search terms: cold hands and feet / what should I do about cold feet? / why is the sole of my foot cold? / in what season does liver disease get better? / liver disease and a black face / several days of constipation — deficiency or excess? / edema with cold hands and feet / what is the difference between yang deficiency and yin deficiency? / why does nourishing yin make me more deficient? / can pulse reading tell when an illness will get better and when it will end in death? / what do the slippery pulse and the rough pulse mean? / what illness is yin excess in Chinese medicine?

Corresponding medical names: Su Wen · Tong Ping Xu Shi Lun (General Discussion on Deficiency and Excess, the twenty-eighth chapter), second half: the definition of deficiency and excess (when evil qi is abundant there is excess, when essence qi is robbed there is deficiency) · lung deficiency, qi rebelling upward, cold feet (yang qi hiding within yin / the lung governs downward depuration / the feet are the tip of yin and yang, and the tip falls ill first) · out of season you live, in season you die (the four-season rhythm of liver disease: rises in spring, holds in winter, recovers in summer, dies in autumn) · the Heavenly Stems and Earthly Branches and the sixty jia-zi cycle that fix life and death (jia-yi wood / bing-ding fire / wu-ji earth / geng-xin metal / ren-gui water; yin-mao wood, si-wu fire, shen-you metal, hai-zi water, chen-xu-chou-wei earth; the illness rises on a pure wood day, recovers on a fire day, dies on a pure metal day) · double excess (a great heat illness with hot qi and a full pulse / channels and collaterals both full, cun urgent and chi slow / the slippery and rough pulses / one whose bones and flesh are slippery can live long) · collateral qi insufficient, channel qi excessive (pulse opening hot and chi region cold / cun yang, chi yin, channels yang, collaterals yin / channels deficient and collaterals full, yang going outward / moxa yin and needle yang to guide yang back into yin) · double deficiency (a deficient pulse is not like yin / when yang is deficient warm the yang, do not nourish yin / classical formulas use yang medicines; Zhang Zhongjing only nourished yin at great deficiency) · cold qi suddenly rising (slippery means life, rough means death / yang jue, yang reversal / the direction of the pulse: chi one inch, cun nine fen) · pulse excess (one excess points to the organs; yin may be full but not excess / liver excess: heart yang cannot descend, hyperactivity without sleep / yin excess flourishes in spring and autumn and brings death in winter and summer / rough and hot is yang desertion) · the whole body swelling full (following means life, opposing means death; warm hands and feet mean life, cold hands and feet mean death)

Opening: feeling all three sections and nine indicators is exhausting — a good doctor looks for the tiniest change

This lecture continues from the previous one on the three sections and nine indicators. Doctor Ni Haixia states the point plainly at the start: the three sections and nine indicators are the principle, but in clinical practice it is impossible to feel every patient’s pulse in all nine positions:

💬 Note from Doctor Ni: The three sections and nine indicators are important. But in clinical practice, you cannot check the three sections and nine indicators on every patient every day — you would be exhausted. That is why I set down the rules of health, which will come out gradually later — they too come from the Huang Di Nei Jing. We do not have that much time to feel all three sections and nine indicators on every person. And what about someone who is across the ocean — far away, in another place? How do you handle that? You cannot even reach his yin pulse. The three sections and nine indicators are just the principle. We have many, many ways to know the beginning of an illness — the moment an illness starts, we can detect it right away. So to be a good doctor you must inspect the tiny change — when an illness is still in its slightest alteration, we already begin to act. In my clinic I use very simple formulas, and I charge very little — just to get people to come and be treated. If one day the great physicians of the whole world all prescribed simple formulas — take Gui Zhi Tang (Cinnamon Twig Decoction) as the first example, very simple — then the whole world would have no patients at all, and that would be the best outcome. That would accord with the way of heaven and earth — the simplest, the cheapest.

What is deficiency and excess, really? When evil qi is abundant there is excess; when essence qi is robbed there is deficiency

Next we enter the Tong Ping Xu Shi Lun — the twenty-eighth chapter of the Huang Di Nei Jing, devoted entirely to deficiency and excess. Doctor Ni first gives the correct meaning of “excess” and “deficiency,” which is completely different from what we usually imagine:

💬 Note from Doctor Ni: When evil qi is very abundant, when it comes on fiercely and the momentum of the illness is violent, we call this excess (shi). When essence qi is robbed, we call this deficiency (xu) — it is not that the person is weak from illness and we call it deficiency; rather, the person’s essence qi has been damaged. That is what is called deficiency. This is the true definition of deficiency and excess.

Constipation for seven days and still eating — that is “excess”

Talking about definitions alone is too abstract, so Doctor Ni immediately gives an example everyone can understand — constipation:

💬 Note from Doctor Ni: Take a person with constipation. One day without a bowel movement is nothing. But seven days without a bowel movement — the stool is blocked inside, and he keeps eating, and it piles up inside — here the evil qi is very strong, and the upright qi will be injured. When it is injured in this way, we say the essence qi has been robbed — this is deficiency. And the patient’s illness was created by the excess evil. That is the definition of deficiency and excess.

Stool blocked for seven days, the intestines full of waste and evil qi — that is excess; the upright qi is dragged down by all this, the essence qi robbed — that is also deficiency. Deficiency and excess can exist at the same time, and the root is usually in the “excess.”

A deficient lung and cold feet: why is the sole of a normal person’s foot warm?

Next Qi Bo speaks of “when the lung is deficient, qi rebels upward and the feet are cold.” Doctor Ni takes this opportunity to explain, very clearly, what a normal person should be like — starting from the feet:

💬 Note from Doctor Ni: In a normal person, the top of the foot (the instep) is cold and the sole is hot. Why? On the top of the foot run the yang channels — the Bladder channel, the Gallbladder channel, the Stomach channel; the three foot-yang channels are on the top and front. The three yin are on the inside — the Spleen channel, the Liver channel, and the Kidney channel running along the sole — the three yin positions. In a normal person, yang is hidden (stored) within yin. So the top of the foot is cold and the sole is hot — that is the normal person. Why? Because the lung is in charge of one great matter — downward depuration: lung qi governs descending and purifying; the yang qi of heaven keeps descending, down, down, all the way to the feet. And heaven is cold, so a person should be cold on the surface and hot within — your outside is icy cold, your inside is hot, that is the normal state. Lung qi governs downward depuration; when lung qi becomes deficient, the heat qi has no way to descend, and the feet turn cold.

Read the feet and you know the illness: the extremities are the body’s most sensitive alarm

So the question arises: why look specifically at the feet? Doctor Ni says the feet are the tip where yin and yang meet, the most sensitive part of the body:

💬 Note from Doctor Ni: The feet are where yin and yang intersect — the very tip of the body. When the body has an illness, where is the most sensitive place? The extremity reacts first. This way we can know the very beginning of the illness. The moment a child catches a cold, the feet turn cold — the whole body is ill, and the toes go cold first. But this is still the early stage. If you do not treat it, the cold grows heavier and heavier, deeper and deeper, until it reaches the bones, and the iciness grows worse and worse. Later, kidney disease patients feel the cold coming out from inside the bones — uremia: the cold always comes out from inside the bones, always starting at the extremities. And this cold keeps climbing upward, up, up, up — when it reaches the body, the person dies. This is where “cold feet” (zu han) comes from.

Out of season you live, in season you die: liver disease has its own four seasons

Next comes a very important passage on prognosis — “out of season you live, in season you die.” Doctor Ni uses liver disease to explain the whole principle:

💬 Note from Doctor Ni: When the liver has a problem, when it meets the one that generates it — its own generation cycle — that is the time of recovery. First, the seasons of liver qi itself: in spring the illness starts, it flares up; in the generating season — when water generates wood — it is the time of holding steady, so a liver patient should be in a stable state in winter; by summer, the season of what it generates (wood generates fire) — it is the time when the illness begins to resolve. So when we treat liver disease, summer should be the time the patient recovers, and winter should be a holding period. Why do you need to know this principle? Everything else follows the same pattern.

Why do we need to know this principle? Doctor Ni says it is the touchstone for judging whether the treatment is heading in the right direction — whether it is Chinese medicine or Western medicine, anything that benefits the patient is permissible:

💬 Note from Doctor Ni: If you have a liver patient in your hands today — I do not care whether you are Chinese or Western medicine, as long as what you do benefits the patient, you may do it. Now suppose this liver patient is being treated by Western doctors, and it is winter — the disease should be holding steady. Ah, but then the face, which was green, turns black — that is the bill coming due, step by step. In other words, if the patient is left alone, left sitting there, he may actually not die. You can judge from this. When the conquering season comes — metal conquers wood — those are all times of death.

The four seasons can be divided — and what about days? Doctor Ni says of course they can: months, days, and hours all can be divided. This leads to the Heavenly Stems and Earthly Branches.

The secret in the stems and branches: sixty days make one jia-zi cycle

The Huang Di Nei Jing says “in season you die.” When it comes down to days, you must rely on the Heavenly Stems and Earthly Branches to calculate. Doctor Ni first teaches the most basic system, and deliberately comforts those who are afraid of stems and branches:

💬 Note from Doctor Ni: For days, we have stems and branches. There are ten Heavenly Stems and twelve Earthly Branches. Some people get dizzy at the sight of the Heavenly Stems — do not think about it, just treat them as symbols. Ten stems, twelve branches. Then the cycle begins again — jia-yi is one complete cycle. Counting from the first day, jia-zi: sixty days later — ten on top, twelve below, the least common multiple of ten and twelve is sixty — so by the sixtieth day, jia-zi appears again. That is the sixty jia-zi. How do we assign the five elements to the twelve branches? Take the four branches chen, xu, chou, wei — all of these are earth; these two (hai, zi) are water; these two (yin, mao) are wood; these two (si, wu) are fire; these two (shen, you) are metal. So among the branches: chen-xu-chou-wei are earth, and the others — wood, fire, metal, water — two each. The stems are easier to calculate: jia-yi are wood, bing-ding are fire, wu-ji are earth, geng-xin are metal, ren-gui are water.

A liver patient: on a “pure wood day” the illness flares; on a “fire day” it recovers

Once the stems and branches are sorted out, how do you use them to calculate life and death in liver disease? Doctor Ni works it out step by step:

💬 Note from Doctor Ni: When your stem is jia or yi, and your branch is yin or mao, that is a pure wood day. Jia meets each of the twelve branches once — it is a cycle. When jia or yi meets the branches yin or mao, that is a pure wood day. If you have liver disease, on a pure wood day the illness flares up — you will see the momentum of the disease is stronger. Then you begin treatment; when the branch reaches si or wu (fire), and the day meets the stems bing or ding — fire days — on a pure fire day, you combine the two and it is a fire day — on the fire day the illness recovers. This is how you diagnose life and death by the day. On a fire day, when the stem is bing or ding and the branch happens to be si or wu, on that very day the liver channel and liver organ return to normal.

And pushing death works the same way:

💬 Note from Doctor Ni: With liver disease, metal is death. If you take the almanac and look at the day stem — geng or xin — and the branch also happens to be shen or you, that is a pure metal day — when the time of metal arrives, that is the time of death. This is: out of season you live, in season you die.

Double excess: heat piled on heat, and the illness becomes severe

On page 237, the Yellow Emperor asks what “double excess” means — two excesses added together. Qi Bo answers: in a great heat illness, with hot qi and a full pulse, that is double excess. Doctor Ni explains:

💬 Note from Doctor Ni: When there is already heat disease on the channels, and then the heat of an exterior pattern comes in, the two are added together — double excess — the excess becomes very heavy. If both channels and collaterals are full, both the channels and collaterals filled with excess signs, what are the symptoms? When the channels and collaterals show pure excess, the cun pulse is urgent and the chi pulse is slow. If your illness is on the channels, the channels are yang and on the surface, so the cun pulse is urgent and the chi pulse slow. You can deduce this — once you grasp one principle of Chinese medicine, the principle of yin and yang, you can deduce everything. The channels are the surface — take the foot-yangming (Stomach channel), for example. Why do we say yangming is the surface? Because the stomach is the interior — and that is the whole explanation.

The slippery pulse and the rough pulse: does qi and blood flow with the current or against it?

Here Doctor Ni teaches how to distinguish the slippery pulse from the rough pulse — the key lies in the direction the qi and blood flow. He uses the Lung channel as an example:

💬 Note from Doctor Ni: For “slippery,” remember the hand-taiyin Lung channel. Its points are Zhongfu LU1, Yunmen LU2, Tianfu LU3, Xiabai LU4, Chize LU5, Kongzui LU6, Lieque LU7, Jingqu LU8, Taiyuan LU9, Yuji LU10, Shaoshang LU11 — eleven points. The channel travels in this direction, so when you feel its pulse, you can feel the qi and blood flowing in that direction, toward the palm — it is like touching water; you should be able to tell which way the water is flowing. That is the slippery pulse. If the water flows against the current, and its momentum is violent, that is the rough pulse — the water flows backward. “Deficiency and excess all begin from their own kind; one whose bones and flesh of the five organs are slippery and supple can live long.” Everything else follows the same pattern — whatever is slippery and flowing is normal. You touch a person’s skin and it is slippery and smooth — that is normal. Touch a severely ill patient — it feels rough, truly rough. After you have felt many pulses you will know: some people who work in hospitals and wander into the wards for no reason, touching patients often — the longer they stay, the less qi they have, and their skin turns rough.

Collateral qi insufficient, channel qi excessive: the pulse opening is hot and the chi region cold

Next Qi Bo speaks of “collateral qi insufficient, channel qi excessive” — the pulse opening is hot and the chi region cold. Doctor Ni says this passage is harder to grasp intuitively, but once you take it apart it is not difficult:

💬 Note from Doctor Ni: Some people explain that the skin of the chi pulse is colder and the skin of the cun pulse is hotter — that is hard, distinguishing hot and cold by the skin over such a short distance. A hot pulse is larger, a cold pulse is smaller — use the pulse itself to distinguish cold and heat, not the skin. So “pulse opening hot and chi cold” means: the pulse at the opening (cun) is comparatively large, and the pulse in the chi region is deep and fine. This illness is collateral qi insufficient, channel qi excessive. If we speak of channels and collaterals versus organs: the channels and collaterals are yang, the organs are yin — so cun is yang and chi is yin. If you further distinguish by channel and collateral: the cun region belongs to the channels, the chi region belongs to the collaterals — this is the channel position, this is the collateral position. So we know that when collateral qi is insufficient and channel qi is excessive, the chi (collateral) pulse becomes comparatively small and the cun (channel) pulse comparatively large. If it is reversed — channels deficient, collaterals full — then the chi pulse is larger and the cun pulse smaller.

Channels deficient and collaterals full is the most dangerous: yang is about to go outward

So why is “channels deficient, collaterals full” dangerous? Doctor Ni says this is the signal that yang qi is leaving the body — that something is about to go wrong:

💬 Note from Doctor Ni: Channels deficient and collaterals full is more dangerous, because the channels are the master. When essence qi is sufficient and the collaterals are insufficient, that is easy to treat. When your channel qi is deficient and the collaterals are strong — what is really happening? The body has yang qi. When yang qi is in danger and something is about to happen, yang always goes outward. When yang goes outward, it starts from the organs, walks to the channels, then to the collaterals. By the time your channels are already deficient and the collaterals full, it means it has already reached the very tip — this is the phenomenon of yang going outward — the pulse at the opening, the cun pulse, becomes small. So when you feel a rough, small yang pulse and a very large yin pulse, you know yang is about to desert, to go outward — this matches our earlier pulse diagnosis. So even if you forget the channels and collaterals, you can still tell by yin and yang. What to do when you meet this? Qi Bo says: moxa the yin, needle the yang. Why do we moxa the yin? To fix the yin — moxa has the power to hold and strengthen; and needle the yang to gather the yang, to keep it from wandering further outward. If it is channels full and collaterals deficient, then needle yin and moxa yang — this is how you guide yang, bring yang back into the yin. In our acupuncture, guiding yang back into yin is done by needling on the yin channels and using moxa on the yang channels — this is the technique of guiding yang into yin.

Double deficiency: when both cun and chi are deficient, what does a yang-deficient person look like?

What is double deficiency? Deficiency piled on deficiency — both the cun and chi pulses, both the yin and yang pulses, are deficient. How do you tell them apart? Qi Bo says by inspection and auscultation. Doctor Ni brings the two to life:

💬 Note from Doctor Ni: Inspection and listening — listen to his voice. When a person is qi-deficient, he speaks without order — what he says does not connect, suddenly he says this, suddenly he says that; the qi is deficient. If a person’s chi pulse is very deficient, the lower yang is deficient — the chi pulse points below; the cun pulse refers to above the chest, the chi pulse refers to below the abdomen — down to the feet — then his steps stagger, he cannot walk properly: lower yang deficiency. “A deficient pulse is not like yin” — people with deficient pulses are all yang-deficient. Remember that: it is yang deficiency. When it is like this, “slippery (hua) means life, rough (se) means death” — when the pulse is very rough, flowing against the current, that is death; when it is slippery, that is life. It is especially noted here: Qi Bo says a deficient pulse is not like yin — that is, what we call yang deficiency. When we are yang-deficient, why do we emphasize yang deficiency? Because we must supplement yang, not nourish yin.

Why can’t you nourish yin in yang deficiency? Why does the classical-formula school love yang medicines?

Doctor Ni then explains thoroughly why “yang deficiency must be supplemented, not nourished by yin” — this is the dividing line between the classical-formula (jing fang) school and the Warm Disease school:

💬 Note from Doctor Ni: We supplement yang; as for nourishing yin, yin will come back by itself — do not nourish yin. Because when you are yang-deficient, yin is already abundant. Yin and yang are mutual — when you become deficient, yin becomes abundant. And you keep nourishing yin, nourishing yin — yang only becomes more deficient. That is why classical formulas use yang medicines in the vast majority of cases, and very rarely use yin-nourishing medicines. Zhang Zhongjing only used yin-nourishing when he saw great deficiency — otherwise he would not. And he had to be certain yang was still present; if yang was deficient, he did not nourish yin but used yang-supplementing medicines. So when we treat anemia, our prescriptions are different from those of the Warm Disease school. This is inspection — watching how he speaks, listening to his voice, watching his walking movements, knowing that he is yang-deficient. Yang is a person’s strength, a person’s focus, a person’s orderliness — speech has sequence. But this person’s speech has no sequence — yang-deficient: in his mind he has no direction, he speaks about this, then that, sometimes suddenly blurting out a sentence that has nothing at all to do with the topic.

Cold qi suddenly rising: the pulse full and hard — slippery means life, rough means death

The Yellow Emperor next asks about “cold qi suddenly rising, the pulse full and hard” — cold qi rebelling upward from the four limbs and reaching the head. Doctor Ni says the key remains slippery versus rough:

💬 Note from Doctor Ni: Cold qi moves upward from the four limbs, rebelling upward to reach the head. Sometimes slippery means life, sometimes rebelling means death. What is meant by slippery: the pulse is very smooth and flowing — this smooth flow follows the direction of the lung qi pulse — this means yang qi is still present. Rebelling means death: flowing against the lung pulse. The direction of the pulse on the hand runs from the chi (one inch) to the cun (nine fen) — the cun side is nine fen in length; this is what we call the normal pulse (chi one inch, cun nine fen). The pulse direction runs from the body upward, toward the palm. Slippery (with the current) — life. Rough: stalled, not advancing, or flowing backward — all dangerous. The rough pulse generally means yang jue, yang reversal — only when yang qi is gone does it stop.

Page 242: pulse excess — cold hands and feet, a hot head, yin and yang reversed

The passage on page 242 is harder to understand, so Doctor Ni warns everyone in advance, then explains it clearly. The Yellow Emperor asks: if the pulse is in excess — cold hands and feet, a hot head — and when you feel the pulse of yin and yang it is both large and hard, what is going on?

💬 Note from Doctor Ni: In a normal person, the hands and feet are warm and the head, face and body are cool. Now it is reversed: the hands and feet are icy cold and the top is hot — yin and yang are reversed. Why? The upper body is yang, the lower body is yin; yang contains yin — so the upper body feels cool and the lower body feels warm: that is the normal person. Now it is reversed: hands and feet cold, the top hot — this is also a death pulse, and we call it pulse excess. Pulse excess has another name: “one excess” — this “one” refers to the organs. Earlier we introduced that the organs can be full — they store, they can store a great deal of nourishment, a granary can be full to the brim — but they cannot be excess, that is, clumped. For example, if my granary stores a lot of flour, and the flour is all dry — fine. But if it becomes damp inside, damp and clumped — that is excess. The liver is yin by nature; yin can be full but cannot be excess.

The “granary” metaphor for yin excess: full is allowed, excess is not

So what is a person like when the liver really is in “excess”? Doctor Ni’s description is striking:

💬 Note from Doctor Ni: When it is in excess, it is like what I just said — dry flour in the warehouse is normal, but now it meets dampness, gets damp, and forms hard lumps one after another. When it is in excess, heart yang — normally heart yang produces heat and then must descend into the small intestine — cannot descend, cannot come down, so it runs upward: the lower limbs are entirely icy, and the top is hot as it goes upward. At the same time there is a hyperactive phenomenon — the patient sits there and cannot lie flat; he just sits, 24 hours without sleep. In the earlier stage he can still eat a little; later, when stomach qi is gone, he starts hiccuping, and departs. This yin excess is all excess signs. When you feel a large pulse, do not panic; when it is hard (excess), without (force) — do not rush; just feel its (size). We often watch others do it this way: one hand on the patient’s hand, the other hand on the patient’s forehead; for children, measure the tip of the finger — this is constipation; do not mistake it, do not be nervous, you cannot be too nervous. Teacher, therefore, the moment I feel (the pulse) I know yang excess, yin excess.

When does yin excess flourish, and when does it kill? It flourishes in spring and autumn and brings death in winter and summer

Qi Bo says yin excess “flourishes in spring and autumn and brings death in winter and summer” — Doctor Ni explains the reasoning behind this seasonal rule:

💬 Note from Doctor Ni: Because spring is cold and autumn is cool, yang qi is not that vigorous, so spring and autumn are the holding (flourishing) seasons; winter and summer bring death — in summer, when yang qi is at its height, it cannot descend but keeps rushing upward; in winter, yang qi hides within — the weakest and the strongest yang are both dangerous. Generally, a floating rough pulse that feels hot is yang desertion. Whenever we feel a rough pulse — the qi mechanism is not smooth, there is a rebelling phenomenon, not going with the current but against it — it is what we call blood deficiency. Blood deficiency; then rough and hot — that is yang desertion: yang is about to desert outward, and these are all death signs.

The whole body swelling full: in an edema patient, warm hands mean life, cold hands mean death

The final question: the Yellow Emperor asks, if a person’s whole body is swollen (edema), what is the condition? Qi Bo answers: when the whole body swells full, the pulse is urgent, large and hard, and the death color does not respond — in such cases, following means life, opposing means death. Doctor Ni translates “following means life, opposing means death” into the easiest sentence to remember:

💬 Note from Doctor Ni: Pulse hard and large — this refers to a person with edema, the whole body swollen up. But to put it simply: when a person is swollen, enlarged, as long as the hands and feet are warm — warm hands mean life, cold hands mean death — that is the great principle. The hands and feet are the extremities of the four limbs, and what they speak of is the chi (pulse) — that is why Qi Bo says the chi pulse is rough and does not respond (hard). If the chi pulse is very hard, returns well and is not rough — bounces well — that is the warmth of the hands and feet. If it is rough but not hard, that is greasiness. To feel the extremities of the four limbs, you feel the chi pulse.

Closing: feel the extremities, ask about the hands and feet — following means life, opposing means death

At the end, the Yellow Emperor presses further: what is meant by “following means life, opposing means death”? Qi Bo closes the entire chapter with one sentence, and Doctor Ni says this sentence is used every day in clinical practice:

💬 Note from Doctor Ni: Qi Bo said: what is meant by following is warm hands and feet; what is meant by opposing is cold hands and feet. This is why we always ask: is your hand cold and your foot hot, or your foot cold and your hand hot? That is how we judge. The hands and feet are the extremities of the four limbs. When the body has an illness, the most sensitive place is the extremity — feel the extremities, ask about the hands and feet: following means life, opposing means death. This is the great judgment of life and death that the Tong Ping Xu Shi Lun teaches us.

Based on Doctor Ni Haixia’s Ren Ji (Human Records) lecture series on the Huang Di Nei Jing (Thirty-Seventh lecture), compiled by Doctor Luo Dalun