帝曰∶时有间二日，或至数日发，或渴或不渴，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。疟者，阴阳更
胜也，或甚或不甚，故或渴或不渴。
疟邪在阴则静，遇阳则动。腑居身中阴分，邪客于腑，与卫阳有时相失而不遇，故间二日或数日一发，
名为三阴疟也。盖卫气行于阳，其气旺，行于阴，其气衰，不能冲动邪气，邪气蓄积数日，与元气俱旺，则病
发。故邪在阳分则浅而从汗泄，为易愈；邪在阴分则深，为难愈也。邪乘阳则热，热甚则渴，不甚亦不渴；
邪乘阴，不热而不渴；或乘阳而挟湿邪，虽热亦多不渴，或口燥而不欲饮者，湿遏阳气，津液不升也。
帝曰∶论言夏伤于暑，秋必病疟。今疟不必应者，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。
疟有不必定发于秋，与论言不相应者，盖四时之气，皆能成疟也。如春风、夏暑、秋凉、冬寒，四时之气
也。其病有异形者，与四时之气相反也。如秋应凉而反热，春应温而反大寒，此其气异，而病亦异，乃变成疟
也。然春为风木主令，其发疟也，则必恶风；夏令阳气发泄，其病疟也，则必多汗。此其病形虽异，而气之升
降浮沉，仍有次序可验。以疟者由伏邪所发，夏令发泄，感邪不觉，至秋外寒骤加，而内邪不容，则必病发，
故论言之也。其三时之气不反，则感邪即病，少有成疟者，故论独举夏伤暑，秋病疟也。其三时之气不反而有
伏邪者，如冬伤于寒，春必病温等，已另有明文矣。
The Yellow Emperor asked: Sometimes malaria occurs every two days, or even after several days; some patients feel thirsty, while others do not. What is the reason for this? Qibo replied: In cases of intermittent occurrence, the pathogenic factor and Wei Qi (Defensive Qi) reside in the Six Fu Organs (Six Yang Organs), but they sometimes fail to meet and interact, thus requiring several days before an attack occurs. Malaria is characterized by the alternating dominance of Yin and Yang. If the imbalance is severe, symptoms are pronounced; if mild, symptoms are less so. Hence, some patients experience thirst, while others do not.
When the malaria pathogen resides in the Yin aspect, it remains static; when it encounters the Yang aspect, it becomes active. The Fu organs are located in the Yin portion of the body. When the pathogen lodges in the Fu organs, it fails to encounter Wei Yang (Defensive Yang) at certain times, resulting in attacks occurring every two days or every few days. This is termed San Yin Malaria (Malaria involving the Three Yin aspects). Generally, when Wei Qi circulates in the Yang aspect, its energy is vigorous; when it circulates in the Yin aspect, its energy is weak, failing to stir up the pathogen. The pathogen accumulates over several days until the Yuan Qi (Original Qi) also becomes vigorous, at which point the disease manifests. Therefore, when the pathogen is in the Yang aspect, the condition is superficial and can be easily resolved through sweating, making it easier to cure; when the pathogen is in the Yin aspect, the condition is deep and difficult to cure. When the pathogen affects the Yang aspect, heat is generated; if the heat is intense, thirst ensues; if not intense, there is no thirst. When the pathogen affects the Yin aspect, there is neither heat nor thirst. Alternatively, if the pathogen affects the Yang aspect but is accompanied by Dampness, although heat may be present, thirst is often absent; or there may be dryness in the mouth without desire to drink, due to Dampness restraining Yang Qi and preventing the ascent of Body Fluids.
The Yellow Emperor asked: The medical texts state that summer injury by Summer-heat leads to autumn malaria. Why does malaria not always correspond to this rule? Qibo replied: This corresponds to the Four Seasons. Cases presenting with atypical forms contradict the general seasonal pattern. Those manifesting 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.
Malaria does not necessarily occur only in autumn, appearing inconsistent with the texts, because the Qi of all four seasons can induce malaria. These include Spring Wind, Summer Summer-heat, Autumn Coolness, and Winter Cold—the Qi of the four seasons. Atypical presentations arise from contradictions with the normal seasonal Qi. For instance, if autumn should be cool but is instead hot, or spring should be warm but is severely cold, such abnormal Qi leads to different diseases, thereby transforming into malaria. However, since Spring is governed by Wind-Wood, malaria arising in spring must involve aversion to wind; during Summer, when Yang Qi is released, malaria must involve profuse sweating. Although these clinical forms differ, the rising, descending, floating, and sinking of Qi still follow a verifiable order. Since malaria originates from latent pathogens, during summer when Yang Qi is released, infection occurs unnoticed. By autumn, sudden external cold prevents the internal latent pathogen from remaining contained, triggering the disease. Thus, the texts emphasize this pattern. In the other three seasons, if the Qi is not abnormal, illness occurs immediately upon infection, rarely forming latent malaria. Therefore, the texts specifically highlight "summer injury by Summer-heat leading to autumn malaria." Regarding latent pathogens in the other three seasons despite non-abnormal Qi, such as winter injury by Cold leading to spring Warmth diseases, these have already been explicitly detailed elsewhere.