经云∶夏伤于暑，秋必 疟。谓夏令伤于暑邪、甚者即患暑病，微者则舍于营，复感秋气凉风，与卫
并居，则暑与风凉合邪，遂成 疟矣。景岳云∶ 者皆也，总疟之称也；疟者虐也，凌虐之义也。疟之为病，
非止一端，当分晰而冶之。考古有暑疟、风疟、寒疟、湿疟、温疟、瘴疟、瘅疟、牝疟、痰疟、食疟、疫
疟、鬼疟、虚疟、劳疟、疟母、三日疟之名，临证之时，不可不辨治也。暑疟者，恶寒壮热，烦渴引饮也。风
疟者，寒少热多，头疼自汗也。寒疟者，寒长热短，头疼无汗也。湿疟者，寒重热轻，一身尽痛也。温疟则
先热后寒，因于冬令伏气。瘴疟则发时昏闷，因感山岚瘴气。瘅疟则独热天寒。牝疟则寒多热少。
又有头痛而眩，疟发昏迷为痰疟。寒热交并，噫气恶食为食疟。沿门合境，证皆相似为疫疟。寒热日作，多
生恐怖为鬼疟。元气本虚，感邪患疟为虚疟。疟疾患久，遇劳即发为劳疟。经年不愈，结成痞块，藏于胁腹
为疟母。正气本虚，邪客于腑，间两日而作者为三日疟。更有似疟非疟之伏暑；亦因伏天受暑而发于秋，最
难速愈。倘秋时炎蒸于夏，而内并无伏气，其见证与阳暑相似者，名曰秋暑。此二证皆在乎秋，今附
论于斯，盖恐误为疟治耳。
暑疟者多因长夏纳凉，感受阴暑，暑汗不出，则邪遂伏于
内，直待秋来，加冒凉气而发。先贤云∶暑气内伏者，阴气也；秋凉外束者，阴邪也；新邪与卫气并居，则
内合伏暑，故阴阳相搏而疟作矣。其证恶寒壮热，口渴引饮，脉来弦象，或洪或软，或着衣则烦，去衣则凛，
肌肤无汗，必待汗出淋漓而热始退。治宜清营捍疟法治之，如渴甚者，麦冬、花粉佐之。凡疟连日而
发者则病浅，间日而发者则病深，间二日而发者则愈深矣。渐早为轻，因正气胜而外出；渐晚为重，因邪气
胜而内入。初起多实，宜以祛邪为先；患久多虚，宜以养正为主。医者须分浅
深轻重虚实新久而治之，则庶几投剂有效耳。
张景岳曰∶伤暑为疟，何谓阴邪？盖阳暑伤气，其证多汗，感而即发，邪不能留。其留藏不去者，惟阴
暑耳，以其无汗也。故凡患疟者，必因于盛暑之时，贪凉取快，不避风寒，或浴以凉水，或澡于河流，或过
食生冷，壮者邪不能居，未必致病，怯者蓄于营卫，则所不免。但外感于寒者多为疟，内伤于寒者
多为痢，使能慎此二者，则疟痢何由来也。
《黄帝内经》说：“夏季被暑邪所伤，到了秋季必定会患疟疾。”这是指在夏令时节感受了暑邪，病情严重的即刻患上暑病；病情轻微的，暑邪便潜伏在营分，到了秋天又再次感受凉风，邪气与卫气共同停留，于是暑邪与风凉之邪结合，从而形成了疟疾。张景岳说：“疟”字通“虐”，是各种疟疾的总称；“疟”字意为“虐”，有欺凌、虐待的意思。疟疾这种病症，并非只有一种类型，应当仔细分辨并治疗。古代医籍中有暑疟、风疟、寒疟、湿疟、温疟、瘴疟、瘅疟、牝疟、痰疟、食疟、疫疟、鬼疟、虚疟、劳疟、疟母、三日疟等名称，临证时不可不加以辨别和治疗。
暑疟的症状是：怕冷且高热，心烦口渴想喝水。风疟的症状是：怕冷少而发热多，头痛且自汗出。寒疟的症状是：怕冷时间长而发热时间短，头痛且无汗。湿疟的症状是：怕冷重而发热轻，全身都疼痛。温疟则是先发热后发冷，是因为冬季伏藏的邪气所致。瘴疟发作时神志昏闷，是因为感受了山林间的瘴气。瘅疟表现为只有发热而没有恶寒。牝疟表现为怕冷多而发热少。又有头痛且眩晕，疟疾发作时昏迷的，称为痰疟。寒热交替出现，嗳气且厌恶饮食的，称为食疟。一家一户、一乡一地，症状都相似的，称为疫疟。每天发作寒热，且患者常产生恐惧心理的，称为鬼疟。元气本来虚弱，感受邪气而患疟疾的，称为虚疟。疟疾病程长久，遇到劳累就发作的，称为劳疟。经年不愈，结成痞块，藏在胁腹部的，称为疟母。正气本虚，邪气客居在腑，每隔两天发作一次的，称为三日疟。更有类似疟疾而非疟疾的“伏暑”；也是因为伏天受暑而在秋季发作，最难迅速痊愈。如果秋季炎热像夏天一样，但体内并没有伏藏的邪气，其表现症状与阳暑相似的，名叫“秋暑”。这两种证候都发生在秋季，现在附论于此，是担心误当作疟疾来治疗罢了。
暑疟大多因为长夏时节贪凉，感受了阴暑，导致暑汗排不出来，邪气便潜伏在体内，一直等到秋天来临，加上遭受凉气侵袭才发作。先贤说：暑气内伏的是阴气；秋凉外束的是阴邪；新的邪气与卫气共同停留，则内部合于伏藏的暑邪，所以阴阳相互搏结而疟疾发作。其症状为怕冷且高热，口渴想喝水，脉象呈弦象，或洪大或软弱，或者穿衣就觉得烦躁，脱衣就觉得寒冷，肌肤无汗，必须等到出汗淋漓之后热势才会消退。治疗适宜用清营截疟法治之，如果口渴严重的，加麦冬、天花粉辅助治疗。凡是疟疾连续几天发作的，说明病位浅；隔一天发作的，说明病位深；隔两天发作的，说明病位更深了。发作时间逐渐提前属于轻症，因为正气胜而邪气外出；发作时间逐渐推迟属于重症，因为邪气胜而邪气内入。初起多为实证，宜以祛除邪气为先；患病日久多为虚证，宜以扶正养正为主。医生必须分辨病位的深浅、病情的轻重以及虚实和新久来进行治疗，这样用药才能见效。
张景岳说：因伤暑而患疟，什么是阴邪呢？大概阳暑耗伤正气，其症状多为出汗，感邪后立即发作，邪气不能留滞。那些留藏不去的，只有阴暑而已，因为它不出汗。所以凡是患疟疾的人，一定是因为在盛夏之时，贪图凉爽取快，不避风寒，或用凉水洗澡，或在河流中沐浴，或过食生冷食物。身体强壮的人，邪气无法停留，未必致病；体弱的人，邪气蓄积在营卫之间，则难免患病。但是，外感寒邪的多为疟疾，内伤寒邪的多为痢疾，如果能谨慎避免这两方面，那么疟疾和痢疾从哪里来呢？
The *Classic of Difficult Issues* (Jing Yun) states: "If injured by summerheat in summer, malaria will inevitably occur in autumn." This refers to contracting summerheat pathogen during the summer months. If severe, one immediately suffers from summerheat disease; if mild, the pathogen resides in the Ying (Nutrient) level. Upon re-exposure to the cool wind of autumn, the pathogen dwells together with the Wei (Defensive) Qi. Thus, summerheat combines with wind-cold pathogens, resulting in malaria. Zhang Jingyue stated: "Nue" (Malaria) is synonymous with "Nüe" (Tyrannical), a general term for all types of malaria; "Nüe" implies the meaning of bullying or tormenting. Malaria is not a single entity but comprises various types that must be differentiated and treated. Ancient texts mention names such as Shu Nue (Summerheat Malaria), Feng Nue (Wind Malaria), Han Nue (Cold Malaria), Shi Nue (Dampness Malaria), Wen Nue (Warmth Malaria), Zhang Nue (Miasma Malaria), Dan Nue (Intense Heat Malaria), Pin Nue (Yin Malaria), Tan Nue (Phlegm Malaria), Shi Nue (Food Stagnation Malaria), Yi Nue (Epidemic Malaria), Gui Nue (Ghost Malaria), Xu Nue (Deficiency Malaria), Lao Nue (Exhaustion Malaria), Nu Mu (Malarial Mass), and San Ri Nue (Every-Third-Day Malaria). These must be distinguished and treated clinically.
Shu Nue (Summerheat Malaria) presents with aversion to cold and high fever, irritability, thirst, and a desire to drink. Feng Nue (Wind Malaria) presents with less aversion to cold and more heat, headache, and spontaneous sweating. Han Nue (Cold Malaria) presents with a longer duration of cold and shorter duration of heat, headache, and absence of sweating. Shi Nue (Dampness Malaria) presents with heavy cold and light heat, and generalized body pain. Wen Nue (Warmth Malaria) presents with heat preceding cold, caused by latent pathogens from winter. Zhang Nue (Miasma Malaria) presents with confusion and drowsiness upon onset, caused by inhaling mountain miasma. Dan Nue (Intense Heat Malaria) presents with isolated heat without cold. Pin Nue (Yin Malaria) presents with more cold than heat. Additionally, headache with vertigo and coma during attacks are termed Tan Nue (Phlegm Malaria). Alternating cold and heat with belching and anorexia are termed Shi Nue (Food Stagnation Malaria). Epidemics affecting households and regions with similar symptoms are termed Yi Nue (Epidemic Malaria). Daily alternating cold and heat accompanied by fear are termed Gui Nue (Ghost Malaria). Malaria contracted due to underlying Yuan Qi deficiency is termed Xu Nue (Deficiency Malaria). Malaria recurring upon exertion after long illness is termed Lao Nue (Exhaustion Malaria). A mass forming in the hypochondrium and abdomen after years of non-healing is termed Nu Mu (Malarial Mass). Malaria occurring every other day due to pathogen lodging in the Fu organs amidst underlying Zheng Qi deficiency is termed San Ri Nue (Every-Third-Day Malaria). Furthermore, there is "Fu Shu" (Latent Summerheat), which resembles malaria but is not it; it occurs in autumn due to summerheat contracted in summer and is difficult to cure quickly. If autumn is hot like summer but there is no latent pathogen internally, and symptoms resemble Yang Shu (Yang Summerheat), it is named Qiu Shu (Autumn Summerheat). These two conditions occur in autumn and are discussed here to prevent misdiagnosis as malaria.
Shu Nue (Summerheat Malaria) often arises from seeking coolness during late summer, contracting Yin Shu (Yin Summerheat). When summerheat sweat does not emerge, the pathogen lies latent within. It remains until autumn, when exposure to cool air triggers its manifestation. Ancients stated: The latent summerheat is Yin Qi; the external binding of autumn coolness is Yin Pathogen. The new pathogen dwells with Wei Qi, combining internally with latent summerheat, causing Yin and Yang to contend and malaria to arise. Symptoms include aversion to cold and high fever, thirst with desire to drink, a wiry pulse, or surging or soft pulses. Patients may feel irritable when clothed and shiver when unclothed. The skin has no sweat; fever subsides only after profuse sweating. Treatment should employ methods to clear the Ying level and intercept malaria. For severe thirst, add Maidong (Ophiopogonis Radix) and Huafen (Trichosanthis Radix). Malaria occurring on consecutive days indicates shallow disease; every other day indicates deeper disease; every third day indicates even deeper disease. Attacks occurring progressively earlier indicate mildness, as Zheng Qi overcomes and expels the pathogen outward; attacks occurring progressively later indicate severity, as the pathogen overcomes and moves inward. Initial stages are mostly excess patterns, prioritizing pathogen expulsion; chronic stages are mostly deficiency patterns, prioritizing nourishing Zheng Qi. Physicians must differentiate depth, severity, excess/deficiency, and acuity/chronicity to ensure effective treatment.
Zhang Jingyue said: Regarding malaria caused by summerheat injury, what is meant by Yin Pathogen? Generally, Yang Shu (Yang Summerheat) damages Qi, presenting with sweating, immediate onset upon contraction, and inability of the pathogen to remain. What remains lodged is only Yin Shu (Yin Summerheat), because it involves absence of sweating. Therefore, those suffering from malaria invariably do so because, during peak summer, they sought coolness recklessly, failed to avoid wind and cold, bathed in cold water, swam in rivers, or consumed excessive raw/cold foods. Robust individuals cannot harbor the pathogen and may not become ill; frail individuals harbor it in Ying and Wei levels and inevitably suffer. However, exogenous cold invasion typically causes malaria, while endogenous cold injury typically causes dysentery. If one guards against these two factors, how would malaria and dysentery arise?