喻昌曰∶圣世御宇，春无愆阳，夏无伏阴，秋无凄风，冬无苦雨，乃至民无夭札，物无疵 ，太和之气，弥满
乾坤，安有所谓瘟疫哉？然周礼傩以逐疫，方相氏掌之，则瘟疫之由来，古有之矣。乡人傩，孔子朝服而致其诚
敬，盖以装演巨象为傩神，不过仿佛具形，圣人以正气充塞其间，俾疫气潜消，乃位育之实功耳！古人元旦汲清泉以
饮芳香之药，上已采兰草以袭芳香之气，重涤秽也。后汉张仲景着《伤寒论》，欲明冬寒春温夏秋暑热之正，自不
能并入疫病，以混常法，至理已毕具于脉法中。叔和不为细绎，乃谓重感于寒，变为温疫。又谓春时应暖而复大寒，
夏时应大热而反大凉，秋时应凉而反大热，冬时应寒而反大温，此非其时而有其气，是以一岁之中，长幼之病，多
相似者，此则时行之气也。又谓冬温之毒，与伤寒大异，冬温复有先后，更相重沓，亦有重轻，治法不同。又谓从
春分节以后，至秋分节前，天有暴寒者，皆为时行寒疫也。盖春夏秋为寒疫，冬月为温疫，所以又云三月四月，或
有暴寒，其时阳气尚弱，为寒所折，病热犹轻。五月六月，阳气已盛，为寒所折，病热则重。七月八月，阳气已衰，
为寒所折，病热亦微。后人奉此而广其义，谓春感清邪在肝，夏感寒邪在心，秋感热邪在肺，冬感温邪在肾，埙篪
递奏，举世若狂矣。嗟嗟！疫邪之来，果为寒折，阳气乘其所胜，而直入精神魂魄之脏，人无 类久矣。更有谓疫
邪无形象声臭，定时定方可言，是以一岁之中，长幼莫不知病此，至病伤寒者，百无一二。治法非疏里则表不透，
非战汗则病不解，愈摹愈远，究竟所指之疫，仍为伤寒、伤温、伤暑热之正病，疏里则下早可知，战汗则失表可知，
只足自呈败阙耳！夫四时不正之气，感之者，因而致病，初不名疫也。因病致死，病气尸气混合不正之气，斯为疫
矣。以故鸡瘟死鸡，猪瘟死猪，牛马瘟死牛马，推之于人，何独不然？所以饥馑兵凶之际，疫病盛行，大率春夏之交
为甚，盖温暑热湿之气，交结互蒸，人在其中，无隙可避，病者当之，魄汗淋漓，一人病气，足充一室，况于连床
并塌，沿门合境，共酿之气，益以出户，尸虫载道，腐 燔柴掩席，委壑投崖，种种恶秽，上溷苍天清净之气，下败
水土物产之气，人受之者，亲上亲下，病从其类，有必然之势。如世俗所称大头瘟者，头面腮颐肿如瓜壳者是也。
所称蛤蟆瘟者，喉痹失音，颈筋胀大者是也。所称瓜瓤瘟者，胸高胁起，呕汁如血者是也。所称疙瘩瘟者，遍身红肿，
发块如瘤者是也。所称绞肠瘟者，腹鸣干吐，水泻不通者是也。所称软脚瘟者，便清泄白，足重难移者是也。小儿
痘疮尤多，以上疫症不明治法，咸委劫运，良可伤悼。大率瘟疫痘疹，古昔无传，不得圣言折衷，是以堕落叔和坑
堑，曾不若俗见摸索病状，反可顾名思义也。昌幸微窥仲景一斑，其平脉篇中云∶寸口脉阴阳俱紧者，法当清邪中于
上焦，浊邪中于下焦。清邪中上，名曰洁也；浊邪中下，名曰浑也；阴中于邪，必内栗也；表气发虚，里气不守，
故使邪中于阴也。阳中于邪，必发热头痛，项强颈挛，腰痛胫酸，所谓阳中雾露之气，故曰清邪中上，浊邪中下，阴
气为栗，足膝逆冷，便溺妄出，表气微虚，里气微急，三焦相溷，内外不通，上焦怫郁，脏气相熏，口烂舌断也。
中焦不治，胃气上冲，脾气不转，胃中为浊，荣卫不通，血凝不流。若卫气前通者，小便赤黄，与热相搏，因热作使，
游于经络，出入脏腑，热气所过则为痈脓。若荣气前通者，阳气厥微，阴无所使，客气入内，嚏而出之，声
咽塞，寒厥相逐，为热所拥，血凝自下，状如豚
肝，阴阳俱厥，脾气孤弱，五液注下，下焦不阖，清便下重，令便数难，脐筑湫痛，命将难全。凡二百六十九字，
阐发奥理，全非伤寒中所有事，乃论血邪从入之门，变病之总，所谓赤文绿字，开天辟地之宝符，人自不识耳！
篇中大意，谓人之鼻气通于天，故阳中雾露之邪者，谓清邪从鼻息而上入于阳，入则发热头痛，项强颈挛，正与
俗称大头瘟、蛤蟆瘟之说符也。人之口气通于地，故阴中水土之邪者，为饮食浊味，从口舌而下入于阴，入则其
人必先内栗，足膝逆冷，便溺妄出，清便下重，脐筑湫痛，正与俗称绞肠瘟、软脚瘟之说符也。然从口从鼻所入之
邪，必先注中焦，以次分布上下，故中焦受邪，因而不治。中焦不治，则胃中为浊，营卫不通，血凝不流，其酿变
即现中焦，俗称瓜瓤瘟、疙瘩瘟等症，则又阳毒痈脓，阴毒遍身清紫之类也。此三焦定位之邪也。若三焦邪混为一，
内外不通，脏气熏蒸，上焦怫郁，则口烂舌断。卫气前通者，因热作使，游行经络脏腑，则为痈脓。营气前通者，
因召客邪，嚏出声 咽塞，热拥不行，则下血如豚肝，然以营卫渐通，故非危候。若上焦之阳，下焦之阴，两不相
接，则脾气于中难以独运，斯五液下注，下焦不阖，而命难全矣。伤寒之邪，先行身之背，次行身之前，次行身之
侧，繇外廓而入。瘟疫之邪，则直行中道，流布三焦，上焦为清阳，故清邪从之上入；下焦为浊阴，故浊邪
从之下入；中焦为阴阳交界，凡清浊之邪，必从此区分。甚者三焦相混，上行极而下，下行极而上，故声 咽塞，口
烂舌断者，亦复下血如豚肝，非定中上不及下，中下不及上也。伤寒邪中外廓，故一表即散。疫邪行在中道，故
表之不散。伤寒邪入胃府，则腹满便坚，故可攻下。疫在三焦，散漫不收，下之复合，此与治伤寒表里诸法，有何干
涉？奈何千年愦愦，试折衷以圣言，从前迷谬，岂不涣然冰释哉！治法未病前，预饮芳香正气药，则邪不能入，此
为上也。邪既入，急以逐秽为第一义。上焦如雾，升而逐之，兼以解毒。中焦如沤，疏而逐之，兼以解毒。下焦如渎，
决而逐之，兼以解毒。营卫既通，乘势追拔，勿使潜滋，详订诸方，载春温方后，或问春夏秋蒸气成疫，岂冬
温独非疫乎？余曰∶冬月过温，肾气不藏，感而成病，正与不藏精之春温无异，计此时有春无冬，三气即得交蒸成疫，
然遇朔风骤起，则蒸气化乌有矣。是以西北土高地燥，即春夏气难上升，何况冬月之凝冱，东南土地卑湿，为雾
露之区，蛇龙之窟，其温热之气，得风以播之，尚有可耐。设旦暮无风，水中之鱼，衣中之虱且为飞扬，况于人乎？
蒸气中原杂诸秽，益以病气尸气，无分老少，触之即同一病状矣。此时朔风了不可得，故其气转积转暴，虽有熏
风，但能送热，不能解凉，盛世所谓解愠阜财者，在兵荒反有注邪布秽之事矣。叔和以夏应大热而反大寒为疫，讵
知大寒正疫气消弥之候乎？故疫邪炽盛，唯北方始能消受，诗恶谮人，思欲投畀有北，以熄其焰，析义精矣。
喻昌说：在圣明君主治理的太平盛世，春天没有过热的阳气，夏天没有潜伏的阴寒，秋天没有凄厉的风，冬天没有苦冷的雨，以至于百姓没有早夭和瘟疫之灾，万物没有病虫害，太和之气充满天地之间，哪里有所谓的瘟疫呢？然而，《周礼》中记载用傩礼来驱逐疫鬼，由方相氏掌管，这说明瘟疫及其防治在古代就已经存在了。孔子在乡人举行傩礼时，穿着朝服以示虔诚恭敬，大概是因为扮演巨大的象形傩神，只是大致具备形状，圣人以正气充盈其中，使疫气悄然消散，这是实现万物生长、养育百姓的实际功效啊！古人在元旦汲取清泉饮用芳香的药物，在上巳节采集兰草熏香，都是为了洗涤污秽。后汉张仲景撰写《伤寒论》，想要阐明冬寒、春温、夏秋暑热的正常规律，自然不能将其并入疫病，以免混淆常规治法，其中的道理已经在脉法中完备地阐述出来了。王叔和没有仔细推究，却说再次感受寒邪，就会变成温疫。又说春季应该温暖却反而大寒，夏季应该大热却反而大凉，秋季应该凉爽却反而大热，冬季应该寒冷却反而大温，这种非其时而有其气的情况，导致一年之中，无论老少生病症状大多相似，这就是时行之气。他又说冬温的毒邪，与伤寒大不相同，冬温又有先后之分，相互重叠，也有轻重之别，治疗方法不同。又说从春分节气以后，到秋分节气以前，天空出现暴寒天气的，都是时行寒疫。大概春夏秋三季为寒疫，冬季为温疫，所以又说三月四月，或许会有暴寒，此时阳气尚弱，被寒气遏制，发病热势较轻。五月六月，阳气已盛，被寒气遏制，发病热势则重。七月八月，阳气已衰，被寒气遏制，发病热势也微弱。后人奉行此说并扩大其含义，认为春季感受清邪在肝，夏季感受寒邪在心，秋季感受热邪在肺，冬季感受温邪在肾，像埙篪合奏一样层层递进，举世若狂。唉！疫邪来袭，如果是被寒气遏制，阳气乘其所胜，直接侵入精神魂魄所在的脏腑，人早就死光了。更有说法认为疫邪没有形象声音气味，只有定时定方才能谈论，因此一年之中，无论老少都知道得这种病，至于得伤寒的，百无一二。治疗方法如果不是疏通里实则表邪不透发，不是通过战汗则病不解，越描摹离真相越远，究竟所指的疫，仍然是伤寒、伤温、伤暑热的正病，疏通里实则可知下法过早，战汗则可知失于解表，只足以暴露自己的缺陷罢了！四季不正之气，感之致病，起初并不称为疫。因病致死，病气与尸气混合不正之气，这才称为疫。所以鸡瘟导致鸡死，猪瘟导致猪死，牛马瘟导致牛马死，推及到人，难道唯独例外吗？所以在饥荒战乱之际，疫病盛行，大体上在春夏之交最为严重，因为温热暑湿之气，交结互相蒸腾，人在其中，没有空隙可以躲避，患病者承受这些，魄汗淋漓，一个人的病气，足以充满一室，何况是连床并榻，沿街满境，共同酝酿的气，加上出门户，路上满是尸虫，焚烧柴草掩盖席子，尸体堆积在山沟悬崖，种种恶秽，上混浊苍天清净之气，下败坏水土物产之气，人受之，亲上亲下，病从其类，有必然的趋势。如世俗所称的大头瘟，就是头面腮颐肿胀像瓜壳一样的。所称的蛤蟆瘟，就是喉痹失音，颈筋胀大的。所称的瓜瓤瘟，就是胸高胁起，呕吐汁液如血的。所称的疙瘩瘟，就是遍身红肿，发块像瘤一样的。所称的绞肠瘟，就是腹鸣干吐，水泻不通的。所称的软脚瘟，就是便清泄白，足重难移的。小儿痘疮尤其多，以上疫病症状不明治法，都委托给劫运，实在令人悲伤哀悼。大体上瘟疫痘疹，古代没有传承，得不到圣人的言论来折衷，所以堕落在王叔和的坑堑中，还不如世俗见解摸索病状，反而可以顾名思义。我有幸略微窥见张仲景的一斑，其平脉篇中说：寸口脉阴阳俱紧的，法当清邪中于上焦，浊邪中于下焦。清邪中上，名叫洁；浊邪中下，名叫浑；阴中于邪，必定内心战栗；表气发虚，里气不守，所以使邪中于阴。阳中于邪，必定发热头痛，项强颈挛，腰痛胫酸，所谓阳中雾露之气，所以说清邪中上，浊邪中下，阴气战栗，足膝逆冷，大小便妄出，表气微虚，里气微急，三焦相混，内外不通，上焦怫郁，脏气相熏，口烂舌断。中焦不治，胃气上冲，脾气不转，胃中为浊，营卫不通，血凝不流。如果卫气先通，小便赤黄，与热相搏，因热作使，游于经络，出入脏腑，热气所过则为痈脓。如果营气先通，阳气厥微，阴无所使，客气入内，嚏而出之，声咽塞，寒厥相逐，为热所拥，血凝自下，状如猪肝，阴阳俱厥，脾气孤弱，五液注下，下焦不阖，清便下重，令便数难，脐筑湫痛，命将难全。凡二百六十九字，阐发奥理，完全不是伤寒中所有的事，乃是论述血邪从入之门，变病的总纲，所谓的赤文绿字，开天辟地的宝符，人们自己不认识罢了！篇中的大意，说人的鼻气通于天，所以阳中雾露之邪的，是说清邪从鼻息而上入于阳，入则发热头痛，项强颈挛，正与俗称大头瘟、蛤蟆瘟的说法相符。人的口气通于地，所以阴中水土之邪的，为饮食浊味，从口舌而下入于阴，入则其人必先内栗，足膝逆冷，便溺妄出，清便下重，脐筑湫痛，正与俗称绞肠瘟、软脚瘟的说法相符。然而从口从鼻所入之邪，必先注中焦，依次分布上下，所以中焦受邪，因而不治。中焦不治，则胃中为浊，营卫不通，血凝不流，其酿变即现中焦，俗称瓜瓤瘟、疙瘩瘟等症，则是又阳毒痈脓，阴毒遍身清紫之类。这是三焦定位之邪。如果三焦邪混为一，内外不通，脏气熏蒸，上焦怫郁，则口烂舌断。卫气前通者，因热作使，游行经络脏腑，则为痈脓。营气前通者，因召客邪，嚏出声咽塞，热拥不行，则下血如豚肝，然而以营卫渐通，所以不是危候。如果上焦之阳，下焦之阴，两不相接，则脾气于中难以独运，斯五液下注，下焦不阖，而命难全矣。伤寒之邪，先行身之背，次行身之前，次行身之侧，由外廓而入。瘟疫之邪，则直行中道，流布三焦，上焦为清阳，故清邪从之上入；下焦为浊阴，故浊邪从之下入；中焦为阴阳交界，凡清浊之邪，必从此区分。甚者三焦相混，上行极而下，下行极而上，所以声咽塞，口烂舌断者，亦复下血如豚肝，并非定中上不及下，中下不及上也。伤寒邪中外廓，所以一表即散。疫邪行在中道，所以表之不散。伤寒邪入胃府，则腹满便坚，所以可攻下。疫在三焦，散漫不收，下之复合，这与治疗伤寒表里诸法，有何干涉？奈何千年糊涂，试以圣人之言来折衷，从前的迷谬，岂不涣然冰释哉！治法在未病前，预先饮用芳香正气药，则邪不能入，这是上策。邪既入，急以逐秽为第一义。上焦如雾，升而逐之，兼以解毒。中焦如沤，疏而逐之，兼以解毒。下焦如渎，决而逐之，兼以解毒。营卫既通，乘势追拔，勿使潜滋，详细订立的各方，载于春温方后，有人问春夏秋蒸气成疫，难道冬温独独不是疫吗？我说：冬季过温，肾气不藏，感而成病，正与不藏精的春温无异，估计此时有春无冬，三气即可交蒸成疫，然而遇到朔风骤起，则蒸气化为乌有了。所以西北土地高地燥，即使春夏气难上升，何况冬季的凝冻，东南土地卑湿，为雾露之区，蛇龙之窟，其温热之气，得风以播之，尚有可耐。假如早晚无风，水中的鱼，衣中的虱且为飞扬，何况于人呢？蒸气中原杂诸秽，加上病气尸气，不分老少，触之即同一病状了。此时朔风了不可得，所以其气转积转暴，虽然有熏风，但能送热，不能解凉，盛世所说的解愠阜财，在兵荒中反而是注邪布秽的事了。王叔和认为夏应大热而反大寒为疫，怎知大寒正是疫气消弥的时候呢？所以疫邪炽盛，唯有北方始能消受，诗厌恶谮人，思欲投畀有北，以熄其焰，析义精矣。
Yu Chang said: In a peaceful era governed by a sage ruler, spring has no excessive yang heat, summer has no latent yin cold, autumn has no desolate wind, and winter has no bitter rain. Consequently, the people suffer no premature death or plague, and all things are free from pests and diseases. The Qi of Great Harmony fills heaven and earth; how could there be such a thing as epidemic pestilence (Wenyi)? However, the *Rites of Zhou* records the use of Nuo rituals to drive away epidemics, managed by the Fangxiang Shi, indicating that the origin of epidemics and their prevention existed since ancient times. When the villagers performed the Nuo ritual, Confucius wore his court robes to show sincerity and reverence. This was likely because the giant elephant-shaped Nuo deity was merely an approximation in form. The Sage filled it with righteous Qi, allowing the epidemic Qi to dissipate secretly. This is the practical achievement of nurturing and sustaining life! On New Year's Day, ancients drew clear spring water to drink aromatic herbs; on the Shangsi Festival, they gathered orchids to perfume themselves, both aiming to cleanse filth. Zhang Zhongjing of the Later Han Dynasty wrote the *Treatise on Cold Damage* (*Shanghan Lun*) to clarify the normal patterns of winter cold, spring warmth, and summer-autumn summerheat. Naturally, he did not merge these into epidemic diseases to avoid confusing standard methods; the principles were fully contained within the pulse diagnosis section. Wang Shuhe failed to analyze this carefully, claiming that secondary contraction of cold transforms into warm epidemics. He also stated that when spring should be warm but is extremely cold, summer should be hot but is extremely cool, autumn should be cool but is extremely hot, and winter should be cold but is extremely warm, this "Qi out of season" causes illnesses among people of all ages to resemble each other, which he called "Seasonal Pathogenic Qi" (Shixing Zhi Qi). He further claimed that winter-warmth toxins differ greatly from cold damage, with variations in timing and severity requiring different treatments. He also defined sudden cold after the Spring Equinox until before the Autumn Equinox as seasonal cold epidemics. Generally, cold epidemics occur in spring, summer, and autumn, while warm epidemics occur in winter. Thus, in March and April, sudden cold may occur when Yang Qi is weak and suppressed by cold, resulting in mild heat symptoms. In May and June, Yang Qi is strong but suppressed, leading to severe heat. In July and August, Yang Qi is declining, so suppression results in mild heat. Later scholars expanded this theory, asserting that spring clears evil affects the Liver, summer cold evil affects the Heart, autumn heat evil affects the Lung, and winter warm evil affects the Kidney, creating a chaotic discourse that drove the world mad. Alas! If epidemic pathogens were truly suppressed by cold, causing Yang Qi to invade the organs of Spirit, Huna, and Po, humans would have perished long ago. Others claim epidemic pathogens lack form, sound, or smell, and can only be discussed with fixed timing and formulas, noting that everyone gets this disease while few get cold damage. They argue treatment must involve purging the interior to release the exterior, or inducing battle-sweat to resolve the disease. This approach drifts further from truth; ultimately, the referred "epidemic" remains the standard cold damage, warm damage, or summerheat damage. Purging interior reveals premature downward action; battle-sweat reveals missed superficial release, exposing one's own deficiencies! Seasonal abnormal Qi causes disease upon contraction but is not initially called an epidemic. Only when disease leads to death, mixing pathogenic Qi with corpse Qi and abnormal Qi, does it become an epidemic. Just as chicken plague kills chickens, swine plague kills pigs, and cattle/horse plague kills cattle and horses, why should humans be different? During famines and wars, epidemics prevail, especially in early spring and summer, when warm, summerheat, and dampness Qi intermingle and steam. People trapped within cannot escape. Patients sweat profusely; one person's pathogenic Qi fills a room. How much more so when beds are adjacent, streets are full, and communal Qi brews, spreading outdoors, with corpses filling roads, burning wood to cover mats, bodies thrown into ravines—various foul odors turbating the pure Qi of heaven and corrupting the Qi of earth and produce. Humans contracting this follow natural tendencies, becoming ill similarly. For example, "Big Head Plague" refers to swelling of the head, face, cheeks, and jaw like a melon shell. "Toad Plague" refers to throat obstruction, loss of voice, and swollen neck tendons. "Melon Rind Plague" refers to chest elevation, rib distension, and vomiting blood-like fluid. "Lump Plague" refers to widespread red swelling and tumor-like lumps. "Intestine Twisting Plague" refers to abdominal borborygmi, dry vomiting, and watery diarrhea without relief. "Soft Leg Plague" refers to clear white loose stools and heavy, immobile legs. Pediatric smallpox is also common. Due to unclear treatments for these epidemics, victims resign to fate, which is deeply sorrowful. Generally, ancient texts lacked transmission on plague and pox, lacking sage authority to judge, leading to errors following Wang Shuhe, whereas folk observations of symptoms might have been more intuitive. I fortunately glimpsed Zhang Zhongjing's insight in his Pulse Chapter: "When Cun Kou pulse is tight in both Yin and Yang positions, clear evil attacks the Upper Jiao, and turbid evil attacks the Lower Jiao." Clear evil attacking above is named "Jie" (Pure); turbid evil attacking below is named "Hun" (Turbid). Contraction of Yin by evil causes internal trembling; deficiency of Exterior Qi and failure of Interior Qi to guard allow evil to enter Yin. Contraction of Yang by evil causes fever, headache, stiff neck, back pain, and leg soreness—this is "Yang contracting mist and dew," hence clear evil enters above, turbid evil enters below. Yin trembling causes cold feet and knees, erratic urination/defecation, slight Exterior deficiency, and slight Interior urgency. The Three Jiaos mix, blocking interior/exterior communication. Upper Jiao stagnation causes organ Qi to熏 (smoke/fume), leading to oral ulcers and tongue severance. Middle Jiao dysfunction causes Stomach Qi to rush upward, Spleen Qi to fail to transform, turbidity in the Stomach, blockage of Ying and Wei Qi, and stagnant blood flow. If Wei Qi flows first, urine becomes dark yellow, clashing with heat, traveling through meridians and organs, causing abscesses/pus where heat passes. If Ying Qi flows first, Yang Qi is weak, Yin has no command, external guest evil enters, causing sneezing, hoarse voice, throat blockage, alternating cold/wild limbs, and heat trapping leading to bloody stool resembling pig liver. Both Yin and Yang collapse, Spleen Qi is weak, five fluids pour downward, Lower Jiao fails to close, causing heavy sensation in clear stool, difficult frequent defecation, umbilical cramping pain, and impending death. These 269 characters elucidate profound principles, entirely distinct from cold damage, describing the gateway for blood evil and general changes in disease—the "red script and green characters," a treasure of creation unrecognized by people! The main idea states: Nose Qi connects to Heaven, so Yang contracting mist/dew means clear evil enters Yang via respiration, causing fever, headache, stiff neck—matching "Big Head Plague" and "Toad Plague." Mouth Qi connects to Earth, so Yin contracting earth/water evil means dietary turbid flavors enter Yin via mouth/tongue, causing internal trembling, cold feet/knees, erratic excretion, heavy stool, umbilical pain—matching "Intestine Twisting Plague" and "Soft Leg Plague." However, evil entering via mouth/nose must first settle in the Middle Jiao, then distribute up/down. Middle Jiao dysfunction leads to stomach turbidity, Ying/Wei blockage, and blood stasis, manifesting as "Melon Rind Plague" and "Lump Plague," akin to Yang toxicity abscesses and Yin toxicity purple skin. This is Three Jiao positional evil. If Three Jiaos mix, blocking interior/exterior, organ fuming causes upper stagnation, oral ulcers. Wei Qi flow causes heat-driven abscesses; Ying Qi flow causes coughing/sneezing, throat blockage, and bloody stool like pig liver. Since Ying/Wei gradually flow, it is not critical. If Upper Yang and Lower Yin do not connect, Spleen Qi cannot operate alone, five fluids pour down, Lower Jiao fails to close, leading to death. Cold damage evil moves from back to front to side, entering from outside. Epidemic evil moves directly through the central pathway, distributing through the Three Jiaos. Upper Jiao is Clear Yang, so clear evil enters from above; Lower Jiao is Turbid Yin, so turbid evil enters from below; Middle Jiao is the boundary of Yin/Yang, distinguishing clear/turbid evil. Severe cases mix Three Jiaos, moving up to extreme then down, down to extreme then up, causing throat blockage, oral ulcers, and bloody stool—not because upper/middle misses lower, or lower/missing misses upper. Cold damage evil enters the outer shell, so releasing the exterior disperses it. Epidemic evil travels the central path, so releasing the exterior fails. Cold damage entering Stomach Fu causes abdominal fullness and hard stool, allowing purgation. Epidemic in Three Jiaos is scattered; purgation causes re-combination. How does this relate to cold damage exterior/interior methods? Why remain confused for millennia? Let us judge by sage words to dissolve confusion! Prevention: Drink aromatic righteous Qi medicine before illness to block entry—this is superior. Once entered, expelling filth is paramount. Upper Jiao is like mist; lift and expel, plus detoxify. Middle Jiao is like fermentation vat; diffuse and expel, plus detoxify. Lower Jiao is like a drain; drain and expel, plus detoxify. Once Ying/Wei flow, pursue and extract pathogens, preventing hidden proliferation. Detailed formulas are in the Spring Warmth section. Question: If spring/summer/autumn vapor forms epidemics, is winter warmth not an epidemic? Answer: Winter excessive warmth prevents Kidney Qi storage, causing disease identical to spring warmth from failing to store essence. At this time, having spring without winter allows three Qi to steam into epidemic. However, sudden north wind evaporates this vapor. Northwest highlands are dry; even spring/summer Qi struggles to rise, let alone winter freezing. Southeast lowlands are damp, foggy, dragon/snake habitats; warm Qi spreads with wind, tolerable. Without wind day or night, fish in water and lice in clothes fly about, let alone humans. Vapor mixes with filth, pathogenic/corpse Qi; all ages contracting it show same symptoms. North wind is unavailable, so Qi accumulates and intensifies. Even warm winds only bring heat, not coolness. What brings peace in prosperous times brings evil spread in war. Wang Shuhe claimed summer extreme cold vs. expected heat is epidemic; he did not know extreme cold is actually when epidemic Qi dissipates. Thus, intense epidemic evil is best handled in the North. The *Classic of Poetry* wishes to cast slanderers north to extinguish flames—a precise analysis.