《素问·疟论》帝曰∶夫 疟皆生于风，其蓄作有时，何也？岐伯曰∶疟之始发也，先起于毫毛，伸欠乃
作，寒 鼓颐，腰脊俱痛，寒去则内外皆热，头痛如破，渴欲冷冻饮料。帝曰∶何气使然？岐伯曰∶阴阳上下交争，
虚实更作，阴阳相移也。阳并于阴，则阴实而阳
虚，阳明虚则寒 鼓颐也；巨阳虚则腰背头项痛；三阳俱虚则阴气胜，阴气胜则骨寒而痛；寒生于内，故中外
皆寒；阳盛则外热，阴虚则内热，内外皆热，则喘而渴，故欲冷冻饮料也。此皆得之夏伤于暑，热气盛，藏于皮
肤之内，肠胃之外，此荣气之所舍也。此令人汗空疏，腠理开，因得秋气，汗出遇风，及得之以浴，水气舍于
皮肤之内，与卫气并居。卫气者，昼日行于阳，夜行于阴，此气得阳而外出，得阴而内薄，内外相薄，是以日作。
起于毫毛伸欠者，毛竖、伸尸、呵欠，疟发之状也。人身表阳内阴，上阳下阴，气血周流，阴阳交通，
则安和无病。疟邪由伤暑热水气，又遇风寒，并客于皮肤之内，肠胃之外，营气所舍之地，故邪与气血混合，
以致阴阳互相格拒，上下交争，虚实更作，阴阳相移，寒则寒极，热则热极。盖水火者，阴阳之征兆，寒热者，
水火之体性，人身阴阳不和，即水火相争，故有寒热之变现也。邪与卫气并居，卫气昼出阳分，夜入阴分，一
日出入一次，故邪随之内外逼迫，而病日发一次。其邪入深，而间一、二日发者，下衣冠文物之。
帝曰∶其间日而作者，何也？岐伯曰∶其气之舍深，内薄于阴，阳气独发，阴邪内着，阴与阳争不得出，
是以间日而作也。
邪在卫分，则随卫气出入而病发。其深舍于阴分者，欲与阳争，而阳行迅利，阴邪迟钝，故不得即出，其
病间日而发也。盖阳如日而行速，阴如月而行迟，造化自然之理也。
帝曰∶其作日晏与其日早者，何气使然？岐伯曰∶
邪气客于风府，循膂而下，卫气一日一夜，大会于风府，其明日日下一节，故其作也晏，此先客于脊背也，
每至于风府则腠理开，腠理开则邪气入，邪气入则病作，以此日作稍益晏也。其出于风府，日下一节，二十
五日，下至 骨，二十六日，入于脊内，注于伏膂之脉，其气上行，九日出于缺盆之中，其气日高，故作日益
早也。
邪之客于身也，本无定处。上明邪客于皮肤之内，肠胃之外，与卫气并居，则日发一次，邪入阴分，则间
日一发，俱无早晏。此节言邪气先客于脊背者，因卫气每日必有大会风府之时，卫气至风府则腠理开，腠理开
则脊背之邪气乘虚而入风府，与卫气相遇则病发也。然卫气会于风府而有定时，以其循度而行也，若邪入风府，
风府督脉穴也，因从脊骨而下行，每日下行一节，故与卫气相遇日迟，而病发日晏也。至二十五日，邪气下至
尾骨，二十六日，入注于脊内伏膂之脉，从上而行，九日出于缺盆之中，因邪气日高，则与卫气相遇日早，
故病发日早也。此以邪气流行而病发有早晏，与前之邪与卫气并居者不同。由是可知疟邪伏于血气之中，如遇
卫阳冲动而后病发，其邪深入阴分而发日迟者，为难愈也。即此推之，经言冬伤于寒，春必病温者，良以冬为
极阴之令，寒为至阴之邪，以阴加阴，故隐伏而不觉，至春阳气升发，则人身之气相应而动其邪，则温病发，
是寒邪随天地之气而变温也。吴又可不明此理，反以经语为非，可谓愚而好自用者。盍思疟邪隐伏时，而亦全
然不觉乎！阴阳变化，微妙无穷，苟不悟其至理，安可凭臆妄断哉！
其间日发者，由邪气内薄于五脏，横连募原也。其道远，其气深，其行迟，不能与卫气俱行，不得皆出，
故间日乃作也。
此又申明间日一发之理也。夫阳动阴静，自然之性，故邪在
阳分，则动而易发，邪在阴分，则伏而不觉，必待阳气冲动，与卫气皆出，则病发。其道远行迟，不能日与卫
气皆出，故间日始发也。其有间两日而发者，邪伏更深矣。然邪必外发而随阳疏泄，始能渐衰，故其深伏阴分
者，淹缠难愈也。
帝曰∶夫子言卫气每至于风府，腠理乃发，发则邪气入，入则病作。今卫气日下一节，其气之发也，不当
风府，其日作者奈何？岐伯曰∶此邪气客于头项，循膂而下者也，故虚实不同，邪中异所，则不得当其风府
也。故邪中于头项者，气至头项而病；中于背者，气至背而病；中于腰脊者，气至腰脊而病；中于手足者，气
至手足而病。卫气之所在，与邪相合则病作。故风无常府，卫气之所发，必开其腠理，邪气之所合，则其府也。
帝谓卫气日会于风府，而亦由节下行，如邪与卫气未遇于风府，其病亦日作者奈何。岐伯言人有虚实不同，
故邪必乘虚而入，各异其处，则不得皆当其风府之穴也。上文言其发病日晏、日早者，因邪先客于脊背，乘卫
气至风府穴，而腠开邪入则病发。如其邪客头项，或中于背，或中腰脊，或中手足，皆无定所，必以卫气周行所
至，与邪遇合则病作。故风邪无常客之府，其卫气所发，必开其腠理，邪气因入，与卫气所合之处，则为其府，
不必定在风府之穴也。由此可知，人身营卫气血周行，自有常度而不改变，其邪之中人，既无定所，而又流传
各处，故其病变多端，经文可谓详尽义理矣。
帝曰∶夫风之与疟也，相似同类，而风独常在，疟得有时而休者，何也？岐伯曰∶风气留其处，故常在；
疟气随经络，沉以内薄，故卫气应乃作。
此更明同由外邪而发病不同之理也。凡感风邪，则身热头痛，而邪常留其处，必服药汗出乃已，既已即不
复发，以其邪去也；疟病发后休歇，歇后又发者，以其邪随经络流行，混于血气之中，沉以内薄，故不之觉，
遇卫阳之气冲动乃发，而卫气周行表里，与邪相离，则邪仍伏而病休歇也。
《素问·疟论》中，黄帝问道：所有的疟病都是由风邪引起的，它们的发作和蓄积都有固定的时间，这是为什么呢？岐伯回答说：疟病刚开始发作时，首先表现为毫毛竖立，接着出现伸懒腰、打哈欠的症状，然后开始发作，表现为寒战鼓颔（牙齿打颤），腰部脊柱都感到疼痛；当寒气退去后，体内和体表都会发热，头痛剧烈得像要裂开一样，口渴想要喝冷饮。黄帝问：是什么气导致这种情况的呢？岐伯说：这是因为阴阳之气上下交争，虚实交替变化，阴阳之气相互移位所致。阳气并入阴分，则阴气实而阳气虚，阳明经气虚则会出现寒战鼓颔的症状；巨阳经（太阳经）气虚则腰背头项疼痛；三阳经（太阳、阳明、少阳）都虚衰时，阴气就会占据优势，阴气盛则骨骼寒冷而疼痛；寒气生于体内，所以内外都感到寒冷；阳气亢盛则体表发热，阴液亏虚则体内发热，内外皆热，就会导致气喘且口渴，所以想喝冷饮。这些情况都是因为夏天被暑邪所伤，热气旺盛，潜伏在皮肤之内、肠胃之外的地方，这是营气（行于脉中的精气）停留的地方。这使得人体汗孔疏松，腠理（皮肤纹理及汗孔）开放，因而受到秋气的侵袭，出汗时遇到风邪，或者洗澡时水气停留在皮肤之内，与卫气（行于脉外的防御之气）共同居住。卫气白天运行于阳分，夜晚运行于阴分，这种邪气随着卫气出于阳分而向外，进入阴分而向内迫近，内外相互搏击，所以每天发作一次。
“起于毫毛伸欠”是指毛发竖起、伸体、呵欠，这是疟病发作时的状态。人身表属阳内属阴，上属阳下属阴，气血周流不息，阴阳交通顺畅，就能安宁无病。疟邪由伤暑、热水气以及风寒之邪共同侵犯，客居于皮肤之内、肠胃之外、营气停留之地，所以邪气与气血混合，导致阴阳互相格拒，上下交争，虚实交替，阴阳移位，冷则冷至极点，热则热至极点。水火是阴阳的象征，寒热是水火的体性特征，人身阴阳不和，就是水火相争，所以会有寒热的表现。邪气与卫气共同居住，卫气白天出于阳分，夜晚进入阴分，一天出入一次，所以邪气随之内外逼迫，疾病每天发作一次。如果邪气侵入较深，间隔一两天才发作的，是因为邪气潜伏的位置较深。
黄帝问：那些隔一天发作一次的，是什么原因呢？岐伯说：因为邪气潜伏的部位较深，内迫于阴分，阳气单独发越，阴邪内着，阴气与阳气争斗而不能外出，所以隔一天发作一次。
邪气在卫分，就随着卫气的出入而发病。如果邪气深深潜伏在阴分，想要与阳气争斗，但阳气运行迅利，阴邪运行迟钝，所以不能立即外出，因此疾病隔一天发作。大概阳气像太阳运行速度快，阴气像月亮运行速度慢，这是自然造化的规律。
黄帝问：那些发作时间越来越晚或越来越早的，是什么气导致的呢？岐伯说：邪气客居在风府穴，沿着脊背向下行走，卫气一天一夜会在风府穴大会，第二天卫气下行一节，所以发作时间越来越晚，这是因为先客居在脊背。每当卫气到达风府穴时，腠理就开放，腠理开放则邪气得以深入，邪气深入则疾病发作，因此每天发作的时间稍微推迟一些。邪气从风府穴出发，每天下行一节，二十五天后下至骶骨，第二十六天进入脊内，注入伏膂之脉，其气上行，九天后出于缺盆之中，邪气位置日益升高，所以发作时间日益提前。
邪气客居在人体内，本来没有固定的处所。上文阐明邪气客居在皮肤之内、肠胃之外，与卫气共同居住，则每天发作一次，邪气进入阴分，则隔一天发作一次，都没有早晚的变化。这一节说的是邪气先客居在脊背的情况，因为卫气每天必定有在风府穴大会的时候，卫气到达风府穴则腠理开放，腠理开放则脊背的邪气乘虚而入风府，与卫气相遇则疾病发作。然而卫气会合于风府是有固定时间的，因为它循着一定的度数运行。如果邪气进入风府（督脉穴位），并从脊骨向下行，每天下行一节，所以与卫气相遇的时间一天天推迟，疾病发作也就一天天变晚。到了第二十五天，邪气下至尾骨，第二十六天进入注于脊内伏膂之脉，从上而行，九天后出于缺盆之中，因为邪气位置日益升高，所以与卫气相遇的时间一天天提前，因此疾病发作也一天天变早。这是以邪气流行而导致疾病发作有早有晚，与前文所说的邪气与卫气共同居住的情况不同。由此可知，疟邪潜伏在血气之中，如果遇到卫阳冲动而后发病，其邪气深入阴分而发作时间推迟的，属于难治之症。由此推论，《内经》所说“冬天感受寒邪，春天必患温病”，确实是因为冬天是极阴的时令，寒邪是至阴的邪气，以阴加阴，所以隐伏而不被发现，到了春天阳气升发，人身之气相应而动，触动邪气，则温病发作，这是寒邪随着天地之气转化为温邪。吴又可不明白这个道理，反而认为经文的话不对，可以说是愚蠢而又喜欢自以为是的人。何不思考一下，疟邪隐伏的时候，也是完全不被察觉的吗！阴阳变化，微妙无穷，如果不领悟其中的至理，怎么能凭主观臆断妄下结论呢！
那些隔一天发作的，是因为邪气内迫于五脏，横连募原（膜原）。其路径远，其气深沉，其运行迟缓，不能与卫气同时运行，不能每次都一起外出，所以隔一天才发作。
这里又申明了隔一天发作一次的道理。阳动阴静，是自然的本性，所以邪气在阳分，则容易发动而发病；邪气在阴分，则潜伏而不被察觉，必须等到阳气冲动，与卫气一同外出，疾病才会发作。因为路径远、运行慢，不能每天都与卫气一同外出，所以隔一天才发作。如果有隔两天才发作的，说明邪气潜伏得更深了。然而邪气必须向外发散并随阳气疏泄，才能逐渐衰减，所以那些深伏在阴分的邪气，缠绵难愈。
黄帝问：先生您说卫气每次到达风府穴，腠理才开放，开放则邪气进入，进入则疾病发作。现在卫气每天下行一节，它发出的时候，不一定在风府穴，那些每天发作的疾病是怎么回事呢？岐伯说：这是因为邪气客居在头项部，沿着脊背向下行走的缘故，所以虚实不同，邪气中伤的处所不同，就不一定正好在风府穴。所以邪气中伤在头项部的，气到达头项部则发病；中伤在背部的，气到达背部则发病；中伤在腰脊部的，气到达腰脊部则发病；中伤在手足部的，气到达手足部则发病。卫气所在之处，与邪气相合则疾病发作。所以风邪没有固定的处所，卫气所发的地方，必然开启其腠理，邪气与之相合的地方，就是它的处所。
黄帝问卫气每天会合于风府，也顺着椎骨下行，如果邪气与卫气未在风府相遇，那些每天发作的疾病是怎么回事。岐伯说人有虚实不同，所以邪气必定乘虚而入，各处不同，就不一定都在风府穴。上文讲发病时间推迟、提前的原因，是因为邪气先客居在脊背，乘卫气到达风府穴，而腠理开邪气入则发病。如果邪气客居头项，或者中伤在背，或者中伤腰脊，或者中伤手足，都没有定所，必须以卫气周行所到之处，与邪气遇合则发病。所以风邪没有固定的客居之处，其卫气所发之处，必然开启其腠理，邪气因而入，与卫气相合之处，就作为它的处所，不一定非要在风府穴。由此可知，人身营卫气血周行，自有常规度数而不改变，邪气中人，既然没有定所，而又流传各处，所以病变多端，经文可谓详尽阐述了义理。
黄帝问：风邪与疟疾，相似且同类，但风邪常常存在，疟疾却有时停止发作，这是为什么呢？岐伯说：风邪留滞在局部，所以常存；疟气随着经络下沉并向内迫近，所以卫气应时而发才发病。
这里进一步阐明同样由外邪引起发病但机理不同的道理。凡是感受风邪，就会出现身热头痛，而邪气常留滞在局部，必须服药出汗才能痊愈，一旦痊愈就不再复发，因为邪气已去；疟病发作后休息，休息后又发作，是因为邪气随着经络流行，混在于血气之中，深沉地向内迫近，所以不易察觉，遇到卫阳之气冲动才发病，而卫气周行于表里，与邪气分离，则邪气仍潜伏而疾病休息。
In the *Su Wen: Treatise on Malaria* (Sùwèn · Nuè Lùn), the Yellow Emperor asked: All malaria diseases are caused by wind pathogen, and their accumulation and发作 have fixed times. Why is this? Qibo replied: When malaria first begins to manifest, it initially presents with hair standing on end, followed by stretching and yawning. Then the attack commences, characterized by shivering with chattering teeth (hán gǔ hé), pain in the waist and spine. When the cold subsides, both internal and external heat arise, causing severe headache as if splitting, thirst, and a desire for cold beverages. The Yellow Emperor asked: What qi causes this? Qibo said: This is due to the upper and lower jiao of yin and yang qi contending with each other, alternating between deficiency and excess, and shifting positions. When yang qi merges into yin, yin becomes full while yang becomes deficient. Deficiency of Yangming channel qi leads to shivering with chattering teeth; deficiency of Juyang (Taiyang) channel qi leads to pain in the waist, back, head, and neck. When all three yang channels (Taiyang, Yangming, Shaoyang) are deficient, yin qi prevails. When yin qi prevails, bones become cold and painful. Cold originates internally, hence both interior and exterior feel cold. When yang is excessive, there is external heat; when yin fluid is deficient, there is internal heat. With both internal and external heat, panting and thirst occur, leading to the desire for cold drinks. These conditions result from summer injury by summer-heat pathogen. The intense heat lingers inside the skin but outside the stomach and intestines, which is where Ying Qi (nutritive qi flowing within vessels) resides. This makes sweat pores loose and Couli (skin texture and pores) open. Consequently, autumn qi invades; sweating combined with exposure to wind, or bathing allowing water qi to settle within the skin, causes the pathogen to reside alongside Wei Qi (defensive qi flowing outside vessels). Wei Qi travels through the Yang aspect during the day and the Yin aspect at night. This pathogen moves outward with Wei Qi emerging into Yang, and inwardly presses with Wei Qi entering Yin. The mutual friction between interior and exterior results in daily attacks.
"Starting with hair standing on end, stretching, and yawning" refers to the state of malaria onset, where hairs erect, the body extends, and one yawns. The human body has exterior Yang and interior Yin, upper Yang and lower Yin. When blood and qi circulate freely and yin and yang communicate smoothly, health and peace are maintained. The malaria pathogen, arising from summer-heat, hot water qi, and wind-cold pathogens, lodges in the area between the skin and the stomach/intestines, the dwelling place of Ying Qi. Thus, the pathogen mixes with blood and qi, causing mutual rejection between yin and yang, contention between upper and lower, alternation of deficiency and excess, and shifting of yin and yang. Cold reaches its extreme, and heat reaches its extreme. Water and fire are manifestations of yin and yang; cold and heat are the natures of water and fire. Disharmony of yin and yang in the body signifies conflict between water and fire, resulting in cold and heat manifestations. The pathogen residing with Wei Qi means that as Wei Qi exits Yang during the day and enters Yin at night, completing one cycle daily, the pathogen is forced inward and outward accordingly, causing daily disease episodes. If the pathogen penetrates deeply, attacks may occur every one or two days due to deeper lodging.
The Yellow Emperor asked: What causes attacks occurring every other day? Qibo replied: Because the pathogen lodges deeply, pressing inwardly on the Yin aspect. Yang qi alone flares up, while Yin pathogen adheres internally. Yin and Yang contend but cannot exit easily, hence the every-other-day pattern.
When the pathogen is in the Wei aspect, it manifests according to the entry and exit of Wei Qi. If it lodges deeply in the Yin aspect, attempting to contend with Yang, Yang moves swiftly while Yin pathogen moves slowly, preventing immediate exit, thus causing every-other-day attacks. Generally, Yang moves fast like the sun, and Yin moves slow like the moon, following natural laws.
The Yellow Emperor asked: What causes attacks to occur later or earlier each day? Qibo replied: When the pathogen lodges in Fengfu (DU16) and descends along the Du Meridian, Wei Qi gathers at Fengfu once daily. The next day, Wei Qi descends one vertebral segment. Thus, attacks occur progressively later because the pathogen initially lodged in the back. Whenever Wei Qi reaches Fengfu, Couli open; when Couli open, pathogen enters; when pathogen enters, disease manifests. Hence, daily attacks occur slightly later. From Fengfu, descending one segment daily, after twenty-five days it reaches the coccyx. On the twenty-sixth day, it enters the spine and injects into the Fulu Zhi Mai (hidden Du vessel). Ascending for nine days, it emerges in Quepen (ST12). As the pathogen rises daily, attacks occur progressively earlier.
Pathogens lodging in the body have no fixed location. Previously stated: pathogen in skin/intestine area with Wei Qi causes daily attacks; pathogen in Yin aspect causes every-other-day attacks, without time variation. This section discusses pathogen initially lodging in the spine. Since Wei Qi must gather at Fengfu daily, when Wei Qi arrives, Couli open, allowing spinal pathogen to enter Fengfu vacuously. Meeting Wei Qi triggers disease. However, Wei Qi's gathering at Fengfu is timed due to its regular course. If pathogen enters Fengfu (a Du Meridian point) and descends one segment daily along the spine, meeting Wei Qi becomes delayed, so attacks occur later. By day 25, pathogen reaches coccyx; day 26, it enters the spine's hidden vessel, ascending. Nine days later, it emerges in Quepen. Rising daily, it meets Wei Qi earlier, so attacks occur earlier. This differs from previous cases where pathogen resided with Wei Qi. Thus, malaria pathogen lies dormant in blood and qi, manifesting only upon stimulation by Wei Yang. Deep lodging in Yin causing delayed attacks indicates difficult-to-treat cases. Inferring from this, the Classic states "Winter injury by cold leads to Spring Warm diseases." Winter is extreme Yin season; cold is extreme Yin pathogen. Yin adding to Yin hides the pathogen unnoticed. In Spring, Yang Qi ascends, stimulating body Qi to activate the pathogen, causing Warm disease. Cold transforms into Warm following Heaven and Earth Qi changes. Wu Keyou failed to understand this, denying the Classic, showing foolish self-opinion. Did he not consider that malaria pathogen is also imperceptible when dormant? Yin-Yang changes are subtle and infinite. Without grasping ultimate principles, how can one judge arbitrarily!
Every-other-day attacks occur because pathogen presses inwardly on the five Zang organs and connects horizontally to Mu Yuan (Membrane Source). The path is long, qi is deep, movement is slow, unable to travel with Wei Qi simultaneously or exit together, hence every-other-day manifestation.
This reiterates the logic of every-other-day attacks. Yang moves, Yin rests, a natural trait. Pathogen in Yang aspect moves easily and manifests; pathogen in Yin aspect lies dormant and imperceptible. It requires Yang Qi stimulation and simultaneous exit with Wei Qi to manifest. Due to long distance and slow speed, it cannot exit daily with Wei Qi, hence every-other-day onset. Attacks every two days indicate even deeper lodging. Pathogen must emerge externally and dissipate with Yang Qi to decline. Thus, deeply lodged Yin pathogen is lingering and hard to cure.
The Yellow Emperor asked: You said Wei Qi reaching Fengfu opens Couli, allowing pathogen entry and disease onset. Now Wei Qi descends one segment daily; when it activates, it is not necessarily at Fengfu. Why do some cases still manifest daily? Qibo replied: This is because the pathogen lodged in the head/neck and descended along the spine. Thus, deficiency/excess varies, and pathogen invasion sites differ, so it does not always align with Fengfu. If pathogen strikes head/neck, disease manifests when Qi reaches head/neck; if back, when Qi reaches back; if waist/spine, when Qi reaches waist/spine; if limbs, when Qi reaches limbs. Disease manifests where Wei Qi meets the pathogen. Therefore, Wind has no fixed "Fu" (abode). Wherever Wei Qi activates, it opens Couli; wherever pathogen combines with Wei Qi, that becomes its abode.
The Yellow Emperor questioned why daily attacks occur if Wei Qi descends segments and might not meet pathogen at Fengfu. Qibo explained that individuals vary in deficiency/excess, so pathogen enters vacuities differently, not always at Fengfu. Earlier, late/early attacks were due to spinal pathogen meeting Wei Qi at Fengfu. If pathogen lodges in head/neck, back, waist, or limbs without fixed location, disease manifests only when circulating Wei Qi encounters it. Thus, Wind has no fixed abode; wherever Wei Qi opens Couli and pathogen enters/meets Wei Qi, that is the abode, not necessarily Fengfu. This shows Ying and Wei Qi circulation follows constant rules. Pathogen invasion has no fixed site and spreads everywhere, causing diverse variations. The Classic elucidates these principles thoroughly.
The Yellow Emperor asked: Wind and Malaria are similar and same category, yet Wind persists constantly while Malaria has remissions. Why? Qibo replied: Wind pathogen stays in its local area, hence persistent; Malaria Qi follows meridians, sinking and pressing inwardly, hence manifesting only when Wei Qi responds.
This clarifies why different diseases arise from external pathogens. Feeling Wind pathogen causes fever and headache; pathogen stays locally, requiring medication to induce sweating for resolution. Once cured, it does not recur because pathogen is expelled. Malaria recurs after remission because pathogen flows with meridians, mixing with blood and qi, sinking inwardly, remaining imperceptible. It manifests only upon Wei Yang stimulation. As Wei Qi circulates interior/exterior, separating from pathogen, pathogen remains dormant and disease remits.