气之所在也，如病在阳则身热而脉躁，病在阴则身寒而脉静，此其应也。病极则阴阳之气俱衰，
阴阳俱衰则卫气与邪气相离，故病得休，此其所以不发也，如明日卫气集与邪相遇，则复病也。
帝曰∶时有间二日，或至数日发，或渴，或不渴，其故何也？
帝承相离则休之意，问疟发时有间二日．或至数日，当其发也。有热甚而渴，有热不甚而不渴，其故何也。
岐伯曰∶其间日者，邪气与卫气客于六腑，而有时相失，不能相得，故休数日乃作也。
其间二日或数日者，邪气与卫气并寒于六腑，卫气入腑，周时
不能外出，而有时相失矣，有时相失，不能与病气相汤，故间二日，或休数日乃作也。
疟者，阴阳更胜，或甚，或不甚，故或渴，或不渴。
常有或渴或不渴之问，故日症者乃阴阳之气，更相胜也。或阳热之气过甚则渴，或阳热之气不甚，则不渴也。
帝曰∶论言夏伤于暑，秋必病疟，今疟不必应者，何也？
《生气通天论》云，夏伤于暑，秋为 疟，帝举以问，今疟有不必为是者，何也？
岐伯曰∶此应四时者也，其病异形者，反四时也，其以秋病者
寒甚，以冬病者，寒不甚，以春病者恶风，以夏病者多汗。
恶，去声。邪气伏藏而病疟，此应四时之升降出入者也，其病异形者，感一时之气而为疟，此反四
时也，其以秋时病疟者，冬伤于寒，阳气内藏，故寒不甚，以春时病疟者，春伤于风，气机始发，
故恶风，以夏时病疟者，夏伤于暑，腠理开，故多汗，此春夏秋冬，皆能病疟，所以明其不必应也。
帝曰∶夫病温疟与寒疟，而皆安舍，舍于何脏？
上文夏受水寒，秋伤于风，藏于腠理皮肤之中，发则先寒后热，名曰寒疟。温疟只言先伤于风，后伤
于寒，未言所受之时，未明所藏之处，帝欲详明温疟之由，故问温疟与寒疟，而皆安舍，舍于何脏，上文因
寒疟而及温疟，故寒疟详而温疟略，此问温疟而兼寒疟，故下文但论温疟，而不复言寒疟也。
岐伯曰∶温疟者，得之冬中于风寒，气藏于骨髓之中，至春则
阳气大发，邪气不能自出，因遇大暑，脑髓烁肌肉消，腠理发泄，
或有所用力，邪气与汗皆出，此病藏于肾，其气先从内出之于外也。
如是者，阴虚而阳盛，阳盛则热矣。衰则气复反入，入则阳虚，阳虚则寒矣。故先热而后寒，名曰温疟。
上中，去声。藏如字，下同。温疟者得之冬，中于风寒，邪气藏于骨髓之中，至春则阳气大发，邪在
骨髓，气行经脉，故邪气不能自出，至夏因遇大暑，暑热上炎，则脑髓烁，暑行肌肉，则肌肉
消，暑开腠理，则腠理发泄，或有所用力，劳其形体，则骨髓之邪气，与汗皆出而为疟，此病邪藏于肾，其
气先从内之骨髓，而出于肌肉腠理之外也。如是者，大暑消烁阴虚而阳盛，阳盛则热矣。阳
热衰，则气复反入，既衰反入则阳虚，阳虚则寒矣，故先热后寒，名曰温疟。寒疟已悉于前，故不复论。
帝曰∶瘅疟何如？
因温疟而复问但热不寒之瘅疟也。
岐伯曰∶瘅疟者，肺素有热，气盛于身，厥逆上冲，中气实而不外泄，因有所用力，腠理开，
风寒舍于皮肤之内，分肉之间，而发，发则阳气盛，阳气盛而不衰，则病矣。其气不反于阴，故但热
而不寒，气内藏于心，而外舍于分肉之间，令人消烁脱肉，故命曰瘅疟。
反，旧本误及，今改。瘅疟者，其人肺素有热，肺主气，肺热则气盛于身，肺气不能外出于皮毛，
则厥逆上冲。上冲者，中气实，而不能外泄也，肺热而实，因有所用力，劳其形体，则腠理
开，腠理在皮肤之内，分肉之间，因其开也。风寒复舍于皮肤之内，分肉之间，而发为疟病，发则阳气
盛，故先热，阳气盛而不衰，故但热不寒，则病瘅疟矣。上文温疟，气复反入，故先热后寒，瘅疟，
其气不反于阴，故但热而不寒，申明气不反阴，但热不寒者，邪热之气，内藏于心，而外舍于分肉之间，
令人消烁脱肉，是以气不反阴，但热不寒，故命曰瘅疟，所以详明瘅疟之所藏者如此。
帝曰∶善。
由瘅疟而推之，则上文少气烦冤，手足热而欲呕，亦火热之气内藏于心，帝故善之。
此一节，论寒疟温疟瘅疟之所由来，及治疟早晏之法也。
Where the pathogenic qi resides, the manifestations differ accordingly: if the disease is in the Yang aspect, the body will be hot and the pulse restless; if the disease is in the Yin aspect, the body will be cold and the pulse quiet. This is the corresponding reaction. When the disease reaches its extreme, both Yin and Yang qi decline. When both Yin and Yang qi decline, the Wei Qi (Defensive Qi) separates from the pathogenic qi, so the illness pauses. This is why it does not manifest at that moment. If the next day the Wei Qi gathers and encounters the pathogenic qi again, the disease will recur.
The Yellow Emperor said: Sometimes malaria occurs every two days, or after several days of interval. Some patients experience thirst, while others do not. What is the reason for this?
Continuing from the previous point regarding the separation of Wei Qi and pathogenic qi leading to a pause, the Yellow Emperor asked about the intervals of two days or several days between malaria attacks. He further inquired why, during an attack, some cases present with severe heat and thirst, while others have mild heat and no thirst.
Qibo replied: In cases occurring every other day, the pathogenic qi and Wei Qi reside in the Six Fu organs. There are times when they miss each other and cannot meet, thus requiring several days before the next attack occurs.
Regarding the intervals of two days or several days, this happens because the pathogenic qi and Wei Qi become stagnant and cold within the Six Fu organs. When the Wei Qi enters the Fu organs, it cannot exit within one double-hour period (Shichen), causing them to miss each other. Because they cannot meet the pathogenic qi, the interval lasts two days, or the patient rests for several days before the next attack.
Malaria is characterized by the alternating superiority of Yin and Yang qi. Sometimes the superiority is severe, sometimes it is not. Therefore, some patients feel thirsty, while others do not.
Since there is often inquiry into why some feel thirsty and others do not, it is stated that malaria involves the mutual superiority and inferiority of Yin and Yang qi. If the Yang-heat qi is excessively strong, thirst occurs; if the Yang-heat qi is not strong, there is no thirst.
The Yellow Emperor said: The treatises state that injury by summer-heat in summer leads to malaria in autumn. However, not all malaria cases follow this pattern. Why is this?
Citing the *Suwen: Lun Sheng Qi Tong Tian* which states, "Injury by summer-heat in summer leads to Jie Malaria (intermittent fever) in autumn," the Yellow Emperor raised this question, noting that current observations show malaria does not always adhere to this rule. Why is that?
Qibo replied: These are cases that conform to the Four Seasons. Those with atypical symptoms deviate from the Four Seasons. Cases occurring in autumn involve severe cold; those in winter involve mild cold; those in spring involve aversion to wind; and those in summer involve profuse sweating.
"Evil" (E) is pronounced with the departing tone. Pathogenic qi lying dormant causes malaria, which conforms to the ascending, descending, exiting, and entering of the Four Seasons. Atypical cases result from contracting qi of a single season, violating the Four Seasons' norms. Autumn malaria results from winter cold injury where Yang qi is stored internally, hence the cold is not severe. Spring malaria results from spring wind injury where the Qi mechanism begins to emerge, hence aversion to wind. Summer malaria results from summer heat injury where the Cou Li (pores/skin texture) open, hence profuse sweating. This demonstrates that malaria can occur in any of the four seasons, clarifying why it need not strictly follow the summer-heat/autumn-malaria rule.
The Yellow Emperor said: Regarding Warm Malaria and Cold Malaria, where do they lodge, and in which Zang organs do they reside?
Previously, it was mentioned that water-cold received in summer and wind injured in autumn hide within the Cou Li and skin, manifesting first as chills then heat, termed Cold Malaria. For Warm Malaria, it only stated initial wind injury followed by cold injury, without specifying the timing or location of storage. The Yellow Emperor sought to clarify the origin of Warm Malaria, asking where both Warm and Cold Malaria lodge and which Zang organs they affect. Since Cold Malaria was discussed previously alongside Warm Malaria, Cold Malaria was detailed while Warm Malaria was brief. Now, asking about Warm Malaria while including Cold Malaria, the following text discusses only Warm Malaria and omits Cold Malaria.
Qibo replied: Warm Malaria originates from wind-cold contraction in winter, with the pathogenic qi hiding in the Marrow. By spring, when Yang qi expands vigorously, the pathogenic qi cannot exit on its own. If met with intense summer heat, the brain marrow is scorched, muscles waste away, and the Cou Li open. If accompanied by physical exertion, the pathogenic qi exits along with sweat. This disease lodges in the Kidney, with its qi moving from the interior to the exterior.
In such cases, Yin deficiency and Yang excess occur. Yang excess leads to heat. As the qi declines, it returns inward; inward return leads to Yang deficiency, which causes cold. Thus, heat precedes cold, named Warm Malaria.
"Zhong" is pronounced with the departing tone. "Zang" is read as written, same below. Warm Malaria arises from winter wind-cold invasion, with pathogenic qi lodging in the Marrow. By spring, Yang qi expands, but the pathogen remains in the Marrow, traveling through the meridians, unable to exit spontaneously. In summer, intense heat scorches the brain marrow; summer heat travels through muscles causing wasting; summer heat opens the Cou Li. Physical exertion causes the pathogenic qi in the Marrow to exit with sweat, resulting in malaria. The pathogen lodges in the Kidney, moving from the internal Marrow to the external Muscles and Cou Li. Such intense summer heat consumes Yin, leading to Yang excess and heat. As Yang heat declines, the qi returns inward; declining and returning inward leads to Yang deficiency and cold. Hence, heat precedes cold, named Warm Malaria. Cold Malaria was fully discussed earlier, so it is not repeated.
The Yellow Emperor said: What about Dan Malaria (Feverish Malaria)?
Following the discussion of Warm Malaria, he asks specifically about Dan Malaria, characterized by heat without chills.
Qibo replied: Dan Malaria occurs in individuals who have pre-existing heat in the Lungs. Qi is abundant throughout the body, reversing upward and rushing against the center. The central Qi is full but cannot vent outward. Due to physical exertion, the Cou Li open, allowing wind-cold to lodge within the skin and between the muscle layers (Fen Rou). Upon manifestation, Yang qi becomes excessive. If Yang qi remains excessive without declining, disease ensues. The qi does not return to Yin, resulting in heat without cold. The qi stores internally in the Heart and externally in the Fen Rou, causing emaciation and wasting. Hence, it is named Dan Malaria.
"Fan" (return): Old editions erroneously wrote "Ji"; corrected here. Dan Malaria affects those with pre-existing Lung heat. The Lung governs Qi; Lung heat causes Qi abundance in the body. Lung Qi cannot vent outward through the skin and hair, leading to rebellious Qi rushing upward. Upward rushing indicates fullness in the center preventing external venting. With Lung heat and fullness, plus physical exertion weakening the form, the Cou Li open. Located inside the skin and between muscle layers, the opening allows wind-cold to re-lodge in the skin and between muscle layers, triggering malaria. Manifestation brings Yang excess, hence heat first. Since Yang excess does not decline, there is only heat and no cold, constituting Dan Malaria. Previously, Warm Malaria involved qi returning inward, causing heat then cold. Dan Malaria's qi does not return to Yin, causing only heat without cold. This clarifies that due to pathogenic heat storing in the Heart and lodging in the Fen Rou, causing emaciation, the qi does not return to Yin, resulting in only heat without cold, thus named Dan Malaria. This details the storage site of Dan Malaria.
The Yellow Emperor said: Excellent.
Inferring from Dan Malaria, the previously mentioned symptoms of shortness of breath, vexation/oppression, heat in the hands and feet, and desire to vomit are also caused by fire-heat qi storing internally in the Heart. Therefore, the Yellow Emperor approved this explanation.
This section discusses the origins of Cold Malaria, Warm Malaria, and Dan Malaria, as well as the principles of early versus late treatment for malaria.