尝读张仲景伤寒论。于太阴有曰。自利不渴者。属太阴。以其脏有寒故也。当温之。宜服四
逆。于少阴有曰。少阴病。得之一二日。口中和。其背恶寒者。当灸之。附子汤主之。少阴
病。身体痛。手足寒。骨节痛。脉沉者。附子汤主之。少阴病下利。白通汤主之。少阴病
下利。脉微者。与白通汤。利不止。厥逆无脉。干呕烦者。白通加猪胆汁汤主之。少阴下利
清谷。里寒外热。手足厥逆。脉微欲绝。身反不恶寒。其人面赤色。或腹痛。或干呕。或咽
痛。或利止脉不出者。通脉四逆汤主之。少阴病脉沉者。急温之。宜四逆汤。于厥阴有曰。
手足厥寒。脉细欲绝者。当归四逆汤主之。大汗。若大下利。而厥冷者。四逆汤主之。观仲景
此论。则伤寒三阴。必有寒证。而宜用温热之剂也。及读刘守真之书。有曰。伤寒邪热在表
。腑病为阳。邪热在里。脏病为阴。俗妄谓有寒热阴阳异证。误人久矣。寒病有矣。非汗病
之谓也。寒病止为杂病。终莫能为汗病。且造化汗液之气者。乃阳热之气。非阴寒之所能
也
。虽仲景有四逆汤证。是治表热里和。误以寒药下之太早。表热入里。下利不止。及或表热
里寒自利。急以四逆温里。利止里和。急解其表也。故仲景四逆汤证。复有承气汤下之者。
由
是伤寒汗病。经直言热病。而不言寒也。经言三阴证者。邪热。在脏。在里。以脏与里。为
阴。当下热者也。素问论伤寒热病有二。篇名曰热。竟无寒理。兼素问并灵枢诸篇。运气造
化
之理推之。则为热病。诚非寒也。观守真此论。则伤寒无问在表在里。与夫三阳三阴。
皆
一于为热。而决无或寒者矣。两说不同。其是非之判。必有一居此者。由是彼此反复究诘
其义。而久不能得。虽至神疲气耗。不舍置者。自谓此是伤寒大纲领。此义不明。则千言万
语。皆未足以为后学式。况戕贼民生。何有穷极也哉。意谓成无己之注。必有所发明者。遂
因而求之。然亦止是随文而略释之。竟不明言何由为热。何由为寒之故。此非其不欲言也。
盖止知伤寒。皆是传经。故疑于六经所传。俱为热证。而热无变寒之理。遂不敢别白耳。以
寒为本脏之寒欤。安得当热邪传里入深之时。反独见寒。而不见热者。且所用温热药。能不
助传经之热邪乎。以寒为外邪之寒欤。则在三阳以成热矣。岂有传至三阴。而反为寒哉。成
氏能潜心乎此。则必悟其所以然矣。自仲景作伤寒论以来。靡或遗之而弗宗。至于异同之论
兴。而渔者走渊。木者走山矣。宜乎后人不能决于似是而非之际。故或谓今世并无真伤寒
病。又或以为今人所得之病。俱是内伤。又昧者。至谓伤寒论中诸温药。悉为传经热邪而用
者。以三阴经属阴故也。又其太谬者。则曰。论中凡有寒字。皆当作热字看。呜呼。末流
之弊。一至此乎。于是澄心静虑以涵泳之。一旦划然若有所悟者。然亦未敢必其当否也。姑
陈之以从有道之正。夫三阳之病。其寒邪之在太阳也。寒郁其阳。阳不畅而成热。阳虽人身
之正 气。既郁则为邪矣。用麻黄发表。以逐其寒。则腠理通。而郁热泄。故汗而愈。苟或
不汗不解。其热不得外泄。则必里入。故传阳明。传少阳。而或入腑也。若夫三阴之病。则
或寒或热者。何哉。盖寒邪之伤人也。或有在太阳经郁热。然后以次而传至阴经者。或有太
阳不传阳明少阳。而便传三阴经者。或有寒邪不从阳经。而始直伤阴经者。或有虽从太阳。
而始不及郁热。即入少阴。而独见少阴证者。或有始自太阳。即入少阴。而太阳不能以无伤
者。或有直伤即入。而寒便变热。及始寒而终热者。其郁热传阴。与变便变热。则为热证。
其直伤阴经。及从太阳即入少阴。则为寒证。其太阳不能无伤。则少阴脉证。而兼见太阳标
病。其始为寒。而终变热。则先见寒证。而后见热证。此三阴之病。所以或寒或热也。苟
即三阴经篇诸条。展转玩绎以求之。理斯出矣。夫其或传经。或直伤。或即入。或先寒后热
者。何也。邪气暴卒。本无定情。而传变不常故耳。故经曰。邪之中人也无有常。或中于阳
。或中于阴。夫守真者。绝类离伦之士也。岂好为异说。以骇人哉。盖由其以温暑为伤寒。
而仲景之方。每不与温暑对。故略乎温热之剂。而例用寒凉。由其以伤寒一断为热而无寒
。故
谓仲景四逆汤。为寒药误下。表热里和之证。及为表热里寒。自利之证。而立。又谓温里止
利。急解其表。又谓寒病止为杂病。嗟乎。仲景伤寒论。专为中而即病之伤寒作。不兼为不
即病之温暑作。故每有三阴之寒证。而温热之剂之所以用也。以病则寒以时。则寒其用之也
固宜。后人不知此意。是以愈求愈远。愈说愈凿。若知此意。则犹庖丁解牛。动中肯綮矣。
且如寒药误下。而成里寒者。固不为不无矣。不因寒药误下。而自为里寒者。其可谓之必无
乎。殊不知阴经之每见寒证者。本由寒邪不由阳经。直伤于此。与夫虽由太阳。而始不及
郁
热。即入于此而致也。虽或有因寒药误下而致者。盖亦甚少。仲景所用诸温热之剂。何尝每
为寒药误下而立。况表里寒之证。亦何尝每有急解其表之文乎。夫里寒外热之证。乃是寒邪
入客于内。迫阳于外。或者虚阳之气。自作外热之状耳。非真热邪所为也。观仲景于里寒外
热之证。但以温药治里寒。而不治外热。则知其所以为治之
意矣。若果当急解其表。岂不于里和之后。明言之乎。且三阴寒病。既是杂病
。何故亦载于伤寒论。以惑后人乎。其厥阴病篇诸条之上。又何故每以伤寒二字冠之乎。夫
内经所叙三阴病。一于为热者。言其常也。仲景所叙三阴病。兼乎寒热者。言其变也。并
行而不相悖耳。后人谓伤寒本无寒证。得非知常而不知变欤。然世之恪守局方。好用温热剂
者。乃反能每全干寒证无他。其守彼虽偏。治此则是。学人能知三阴。固有寒邪所为之证。则
仲景创法之本意。可以了然于心目之间。而不为他说所夺矣。或曰。伤寒之病。必从阳经郁
热。而传三阴今子谓直伤阴经。即入阴经。而为寒证。其何据乎。予曰。据夫仲景耳。仲景
曰。病发热恶寒者。发于阳也。无热恶寒者。发于阴也。发于阳者。七日愈。发于阴者。六
日愈。夫谓之无热恶寒。则知其非阳经之郁热矣。谓之发于阴。则知其不从阳经传至此矣。
谓之六日愈。则知其不始太阳。而止自阴经发病之日。为始数之矣。仲景又曰。伤寒一二日
。至四五日。而厥者。必发热。伤寒病厥五日。热亦五日。设六日当复厥。不厥者。自愈。
伤寒厥四日。热反三日。复厥五日。其病为进。夫得伤寒未为热。即为厥者。岂亦由传经
入深之热邪。而致此乎。今世人多有始得病时。便见诸寒证。而并无或热者。此则直伤阴经
。即入阴经者也。苟不能究夫仲景之心。但执凡伤于寒。则为病热之语以为治。其不夭人天
年者。几希矣。
我曾阅读张仲景的《伤寒论》。在太阴病篇中提到：“自利不渴者，属太阴。以其脏有寒故也。当温之，宜服四逆汤。”在少阴病篇中提到：“少阴病，得之一二日，口中和，其背恶寒者，当灸之，附子汤主之。”“少阴病，身体痛，手足寒，骨节痛，脉沉者，附子汤主之。”“少阴病下利，白通汤主之。”“少阴病下利，脉微者，与白通汤；利不止，厥逆无脉，干呕烦者，白通加猪胆汁汤主之。”“少阴下利清谷，里寒外热，手足厥逆，脉微欲绝，身反不恶寒，其人面赤色，或腹痛，或干呕，或咽痛，或利止脉不出者，通脉四逆汤主之。”“少阴病脉沉者，急温之，宜四逆汤。”在厥阴病篇中提到：“手足厥寒，脉细欲绝者，当归四逆汤主之。”“大汗，若大下利，而厥冷者，四逆汤主之。”观察张仲景的这些论述，那么伤寒三阴病（太阴、少阴、厥阴），必然存在寒证，并且适宜使用温热性质的方剂。
等到我阅读刘完素（字守真）的著作时，其中有这样的说法：“伤寒邪热在表，腑病为阳；邪热在里，脏病为阴。世俗荒谬地认为有寒热阴阳不同的证候，误导人很久了。寒病是有的，但这不是指‘汗病’（即广义的伤寒热病）。寒病仅属于杂病范畴，终究不能成为‘汗病’。况且自然界产生汗液之气的原因，乃是阳热之气的作用，并非阴寒之气所能造成的。”虽然张仲景有四逆汤的证治条文，但那是治疗表热里和，误用寒凉药过早攻下，导致表热入里，下利不止；或者是表热里寒导致的自利，急需以四逆汤温补里阳，待利止里气调和后，再紧急解除表邪。所以张仲景的四逆汤证之后，又有用承气汤攻下的情况。因此，《内经》直言伤寒是热病，而不说是寒病。《内经》所说的三阴证，是指邪热在脏、在里，因为脏与里属阴，所以需要攻下热邪。《素问》论述伤寒热病有两篇，篇名都叫《热论》，完全没有关于寒的理论。结合《素问》和《灵枢》各篇，从运气造化之理推导来看，这确实是热病，确实不是寒病。观察刘完素的这些论述，那么伤寒无论病位在表在里，无论是三阳还是三阴，全都统一为热证，绝对没有寒证了。
这两种说法不同，其中是非的判断，必定有一方是正确的。于是我对彼此的观点反复探究诘问其义理，却长久以来无法得出定论，甚至到了精神疲惫、元气耗损的地步，仍不放弃。我自认为这是伤寒的大纲领，如果这个义理不明确，那么千言万语都不足以作为后学的典范，更何况残害百姓生命，哪有穷尽的时候呢？我想成无己的注解，一定有发明之处，于是顺着他的注释去寻求答案。然而他也只是随着文意略微解释，竟然没有明确说明为什么会有热、为什么会有寒的缘故。这并不是他不想说，大概是因为只知道伤寒都是传经而来的，所以怀疑六经所传的病症，全都是热证，而热证没有转变为寒证的道理，于是不敢分辨罢了。如果说寒是本脏固有的寒，那么怎么会在热邪传入体内深处时，反而单独出现寒象，而不见热象呢？况且所使用的温热药物，难道不会助长传经的热邪吗？如果说寒是外来的邪气之寒，那么在三阳经就已经化热了，怎么传到三阴经反而变成寒了呢？如果成无己能潜心研究这个问题，就一定能领悟其中的原因了。
自从张仲景撰写《伤寒论》以来，没有人遗漏它而不尊崇它。直到异同争论兴起，就像捕鱼的人奔向深渊，砍柴的人奔向大山一样（意指各执一端，偏离正道）。难怪后人不能在似是而非的情况下做出决断。所以有人说当今世上并没有真正的伤寒病；又有人认为今人所得的病，全都是内伤病；又有愚昧的人，甚至说《伤寒论》中的各种温热药，全都是为了治疗传经热邪而使用的，因为三阴经属阴的缘故。更为荒谬的说法则是：《伤寒论》中凡是出现“寒”字的地方，都应该当作“热”字来看待。唉！末流的弊端，竟然到了这种地步吗？于是我澄澈心灵，静思冥想，沉浸其中。有一天豁然开朗，好像有所领悟，但也未必敢断定是否正确。姑且陈述出来，以听从有道之人的指正。
夫三阳病的寒邪在太阳经时，寒邪郁遏阳气，阳气不畅而化为热。阳气虽然是人体的正气，一旦郁结就成为邪气了。使用麻黄汤发表，以驱逐寒邪，则腠理通畅，郁热得以宣泄，所以发汗而痊愈。如果不发汗而病不解，其热不得向外宣泄，就会向内传入。所以传入阳明、少阳，或者进入腑。至于三阴病，为什么有的寒、有的热呢？大概寒邪伤人，有的是在太阳经郁热，然后依次传入阴经；有的是太阳经不传给阳明、少阳，就直接传入三阴经；有的是寒邪不从阳经开始，而是直接伤害阴经；有的是虽然从太阳经开始，但还没来得及郁积化热，就立即进入少阴，只见到少阴的证候；有的是起初就在太阳，随即进入少阴，而太阳经也不能不受损伤；有的是直接受伤随即进入，寒邪就变为热，以及起初是寒最终变为热的。那些由郁热传入阴经，以及由寒变热而成的，就是热证；那些直接伤害阴经，以及从太阳随即进入少阴的，就是寒证。太阳经不能不受损伤，则少阴的脉证中兼见太阳标病的症状。起初是寒，最终变为热，则先见到寒证，而后见到热证。这就是三阴病之所以有的寒、有的热的原因。如果仔细研读三阴经篇的各条内容，辗转推究以求索其理，道理自然显现。
至于为什么有的传经、有的直伤、有的即入、有的先寒后热呢？这是因为邪气暴烈突然，本来就没有固定的情状，而且传变不常规律所致。所以《内经》说：“邪气中人没有固定规律，有的中于阳，有的中于阴。”刘完素是一位超群绝伦的士人，难道喜欢提出异端学说以惊骇世人吗？大概是因为他把温病、暑病归为伤寒，而张仲景的方剂，往往不与温病、暑病相对应，所以他忽略了温热方剂，一律使用寒凉药。因为他把伤寒一概断定为热而无寒，所以说张仲景的四逆汤，是为误用寒药攻下表热里和之证，以及为表热里寒自利之证而设立的。又说温里止利后，紧急解除表邪。又说寒病仅属于杂病。唉！张仲景的《伤寒论》，专门针对感受寒邪即刻发病的“伤寒”而作，并不兼及感受寒邪过一段时间才发病的“温病”和“暑病”。所以常常有三阴病的寒证，这也是使用温热方剂的原因。因为病是寒性的，时令也是寒性的，使用温热药固然适宜。后人不知道这个意思，所以越是探求越远，越是解说越固执。如果知道这个意思，那就如同庖丁解牛，动作都能切中要害了。
况且像因误用寒药攻下而导致里寒的情况，固然不能说没有。但不因误用寒药攻下，而自己形成里寒的情况，能说一定没有吗？殊不知阴经每见寒证，原本是由寒邪不由阳经直接伤害于此，以及虽然由太阳经开始，但还没来得及郁积化热，就立即进入阴经而导致的。虽然或许有因误用寒药攻下而导致的，但也很少。张仲景所用的各种温热方剂，何尝每次都是为误用寒药攻下而设立的？况且表里寒热的证候，又何尝每次都提到紧急解除表邪的文字呢？所谓里寒外热的证候，乃是寒邪侵入内部，逼迫阳气浮越于外，或者是虚阳之气，自己表现出外热的样子罢了，并不是真正的热邪所为。观察张仲景对于里寒外热的证候，只用温药治疗里寒，而不治疗外热，就知道他治疗的用意了。如果果真应当紧急解除表邪，难道不在里气调和之后，明确说明吗？况且三阴寒病，既然是杂病，为什么要记载在《伤寒论》中，来迷惑后人呢？在其厥阴病篇各条之上，为什么要每都以“伤寒”二字冠首呢？
《内经》所叙述的三阴病，全是热证，说的是常理；张仲景所叙述的三阴病，兼有寒热，说的是变理。两者并行而不相违背。后人说伤寒本来没有寒证，岂不是只知常理而不知变理吗？然而世间那些恪守《局方》、好用温热方剂的人，反而能每每保全那些寒证，没有其他弊病。他们坚守的方法虽然偏颇，但治疗这类疾病却是正确的。学医的人如果能知道三阴病固有寒邪所致的证候，那么张仲景创立法则的本意，就可以在心目之间了然于胸，而不被其他学说所夺走。
有人问：“伤寒的病，必然从阳经郁热，然后传入三阴。现在您说直接伤害阴经，随即进入阴经，而为寒证，有什么依据呢？”我说：“依据张仲景的话。张仲景说：‘病发热恶寒者，发于阳也；无热恶寒者，发于阴也。发于阳者，七日愈；发于阴者，六日愈。’称为无热恶寒，就知道它不是阳经的郁热；称为发于阴，就知道它不从阳经传至此；称为六日愈，就知道它不始于太阳经，而是以自阴经发病之日作为起始计数的日子。”张仲景又说：“伤寒一二日，至四五日，而出现四肢厥冷的，必定会发热。伤寒病四肢厥冷五日，发热也五日，假如第六天应当再次出现厥冷，如果不出现厥冷，就会自愈。伤寒四肢厥冷四天，发热反而三天，再次厥冷五天，病情为进展。”得到伤寒病还没有发热，就出现四肢厥冷的，难道也是由传经深入的热邪导致的吗？如今世人多有人在刚开始患病时，就见到各种寒证，而并没有任何热象，这就是直接伤害阴经，随即进入阴经的情况。如果不能探究张仲景的心意，只是执着于凡是伤于寒邪，就会得热病的言论来治疗，不夭折寿命的人，就太少了。
I once read Zhang Zhongjing's *Treatise on Cold Damage Diseases* (*Shanghan Lun*). In the section on Taiyin disease, it states: "Spontaneous diarrhea without thirst belongs to Taiyin. This is because there is cold in the zang organs. It should be treated with warming methods; Sini Decoction (Four Reversal Decoction) is appropriate." In the section on Shaoyin disease, it states: "Shaoyin disease, developing within one or two days, with a normal mouth and tongue, and aversion to cold on the back, should be treated with moxibustion; Fuzi Tang (Aconite Decoction) governs it." "Shaoyin disease, with body pain, cold hands and feet, bone and joint pain, and a deep pulse, is governed by Fuzi Tang." "Shaoyin disease with diarrhea is governed by Baitong Tang (White Tongue Decoction)." "In Shaoyin disease with diarrhea and a faint pulse, administer Baitong Tang; if diarrhea does not stop, accompanied by reversal cold, absence of pulse, dry retching, and irritability, Baitong Jia Zhuyedanhuang Tang (Baitong Decoction plus Pig Gallbladder Bile Decoction) governs it." "Shaoyin with clear undigested food in stool, internal cold with external heat, cold hands and feet, pulse faint and nearly absent, yet the body shows no aversion to cold, and the person has a red face, or abdominal pain, or dry retching, or sore throat, or diarrhea stops but pulse does not emerge, is governed by Tongmai Sini Tang (Pulse-Resuscitating Sini Decoction)." "In Shaoyin disease with a deep pulse, urgently warm it; Sini Tang is appropriate." In the section on Jueyin disease, it states: "Cold hands and feet with a fine and nearly absent pulse are governed by Danggui Sini Tang (Angelica Sinensis Decoction for Reversal Cold)." "After profuse sweating, or severe purgation, resulting in cold extremities, Sini Tang governs it." Observing these discussions by Zhang Zhongjing, it follows that the Three Yin diseases (Taiyin, Shaoyin, Jueyin) of cold damage must have cold syndromes and are suitable for treatment with warming agents.
Later, when I read the works of Liu Wansu (courtesy name Shouzhen), he stated: "When pathogenic heat from cold damage is in the exterior, fu organ diseases are Yang; when pathogenic heat is in the interior, zang organ diseases are Yin. The vulgar erroneously claim there are distinct syndromes of cold, heat, Yin, and Yang, misleading people for a long time. Cold diseases exist, but they do not refer to 'Han Bing' (the generalized term for febrile diseases transmitted via sweating). Cold diseases belong only to miscellaneous diseases and can never constitute 'Han Bing'. Moreover, the qi that generates sweat in nature is Yang-heat qi, not something Yin-cold can produce." Although Zhang Zhongjing has indications for Sini Tang, those are for treating cases where exterior heat exists with interior harmony, but were mistakenly treated too early with cold-purgative herbs, causing exterior heat to enter the interior and resulting in persistent diarrhea; or for cases of self-induced diarrhea due to exterior heat and interior cold, requiring urgent warming of the interior with Sini Tang. Once diarrhea stops and interior harmony is restored, the exterior syndrome should be urgently resolved. Thus, after indications for Sini Tang in Zhang Zhongjing's work, there are instances of using Chengqi Tang (Descending Qi Decoction) for purgation. Therefore, the Classics explicitly state that cold damage is a heat disease, not a cold one. The Three Yin syndromes mentioned in the Classics refer to pathogenic heat residing in the zang organs and the interior; since zang organs and the interior are Yin, purging the heat is required. The *Suwen* discusses cold damage febrile diseases in two chapters, both titled "Re" (Heat), containing no theory on cold. Inferring from the principles of fate and transformation in various chapters of the *Suwen* and *Lingshu*, these are indeed heat diseases, certainly not cold. Observing Liu Shouzhen's arguments, it follows that cold damage, regardless of whether the pathogen is in the exterior or interior, and whether it involves the Three Yang or Three Yin, is uniformly a heat syndrome, absolutely devoid of cold.
These two theories differ. In judging right from wrong, one must be correct. Thus, I repeatedly investigated and questioned the meanings of both sides, unable to reach a conclusion for a long time, becoming so exhausted in spirit and energy that I could not let go. I considered this to be the general principle of cold damage. If this principle is unclear, then thousands of words are insufficient as models for later learners, let alone the endless harm inflicted upon people's lives. I thought that Cheng Wuji's commentary must have some insights, so I sought answers through his text. However, he merely explained briefly along with the text, never explicitly stating why there is heat or why there is cold. This was not because he did not want to say it, but likely because he believed that cold damage always involves transmission through the meridians, leading him to suspect that all transmissions through the Six Meridians result in heat syndromes, and that heat cannot transform into cold. Hence, he dared not distinguish them. If cold is inherent to the zang organs, how can it appear exclusively as cold, without heat, when hot pathogens transmit deeply into the interior? Furthermore, would the use of warming herbs not aid the transmitting heat pathogens? If cold is an external pathogenic factor, it would have already transformed into heat in the Three Yang meridians. How could it become cold upon reaching the Three Yin meridians? If Cheng Shi had pondered this deeply, he would surely have realized the reason.
Since Zhang Zhongjing wrote the *Treatise on Cold Damage Diseases*, no one has neglected it without revering it. Until debates on similarities and differences arose, like fishermen rushing to the abyss and woodcutters to the mountains (indicating straying from the true path), it is no wonder later generations could not decide at the ambiguous juncture. Thus, some claimed there are no true cold damage diseases in the current era; others argued that diseases contracted today are all internal injuries; and ignorant individuals went so far as to say that all warming medicines in the *Treatise* are used for heat pathogens transmitted through meridians because the Three Yin meridians belong to Yin. Even more absurd was the claim that every instance of the character "cold" in the treatise should be read as "heat". Alas! Have the drawbacks of degeneration reached such a point? I then cleared my mind and contemplated deeply. One day, it suddenly became clear as if I had gained enlightenment, though I dared not assert its correctness. I tentatively present it here for correction by those who possess the Way.
Regarding the diseases of the Three Yang, when cold pathogens reside in the Taiyang meridian, cold constrains Yang qi, which becomes unsmooth and transforms into heat. Although Yang qi is the righteous qi of the human body, once constrained, it becomes pathogenic. Using Mahuang Tang (Ephedra Decoction) to release the exterior and expel cold allows the couli (pores) to open and constrained heat to vent, resulting in cure through sweating. If sweating does not resolve the condition, the heat cannot vent outward and must enter the interior. Thus, it transmits to Yangming or Shaoyang, or enters the fu organs. As for the diseases of the Three Yin, why are some cold and some heat? Generally, when cold pathogens injure the human body, sometimes heat is constrained in the Taiyang meridian before sequentially transmitting to the Yin meridians; sometimes Taiyang does not transmit to Yangming or Shaoyang but directly transmits to the Three Yin meridians; sometimes cold pathogens do not start from the Yang meridians but directly injure the Yin meridians; sometimes although starting from Taiyang, heat is not yet constrained, and it immediately enters Shaoyin, showing only Shaoyin syndromes; sometimes starting from Taiyang, it immediately enters Shaoyin, while Taiyang is still injured; sometimes direct injury leads immediately to entry, and cold transforms into heat, or starts as cold and ends as heat. Those resulting from constrained heat transmitting to Yin, or transforming from cold to heat, are heat syndromes. Those directly injuring the Yin meridians, or entering Shaoyin immediately from Taiyang, are cold syndromes. When Taiyang cannot avoid injury, Shaoyin pulse and syndromes will co-occur with Taiyang manifest symptoms. When starting as cold and eventually transforming into heat, cold syndromes appear first, followed by heat syndromes. This is why the diseases of the Three Yin are sometimes cold and sometimes heat. If one carefully studies and interprets the various clauses in the Three Yin meridian chapters, the principles will emerge.
Why are there cases of transmission, direct injury, immediate entry, or initial cold followed by heat? This is because pathogens strike violently and suddenly, lacking fixed patterns, and their transmission and transformation are irregular. Thus, the Classics state: "Pathogens invading humans have no constancy; some invade Yang, some invade Yin." Liu Shouzhen was a scholar of exceptional caliber. Did he enjoy proposing heterodox theories to shock people? Probably because he categorized Warm Disease and Summerheat as Cold Damage, and Zhang Zhongjing's formulas often did not correspond to Warm Disease and Summerheat, he overlooked warming agents and universally employed cold-cooling herbs. Because he judged all cold damage as heat without cold, he claimed that Zhang Zhongjing's Sini Tang was established for cases where cold herbs were mistakenly used to purge, leaving exterior heat with interior harmony, or for cases of exterior heat with interior cold causing self-diarrhea. He further stated that after warming the interior to stop diarrhea, the exterior should be urgently resolved. He also claimed cold diseases belong only to miscellaneous diseases. Alas! Zhang Zhongjing's *Treatise on Cold Damage Diseases* was specifically composed for "Shanghan" (cold damage occurring immediately upon exposure to cold), not for "Wenshu" (warm diseases and summerheat occurring after a latent period). Therefore, there are frequently cold syndromes in the Three Yin, which explains the use of warming agents. Since the disease is cold and the season is cold, using warming agents is indeed appropriate. Later generations, unaware of this meaning, seek further away and argue more rigidly. If they understood this, it would be like Cook Ding carving an ox, moving precisely at the joints.
Moreover, while cases of interior cold caused by mistaken purgation with cold herbs certainly exist, can we say that interior cold arising spontaneously without such mistake is impossible? Little do they know that the frequent appearance of cold syndromes in the Yin meridians originally stems from cold pathogens directly injuring these meridians without passing through the Yang meridians, or from Taiyang failing to constrain heat before immediately entering these meridians. Although some may result from mistaken purgation with cold herbs, this is rare. Were the various warming agents used by Zhang Zhongjing established solely for mistaken purgation? Furthermore, in cases of exterior-interior cold-heat syndromes, is there ever mention of urgently resolving the exterior? The syndrome of interior cold with external heat occurs when cold pathogens invade internally, forcing Yang qi to the exterior, or when deficient Yang qi manifests as external heat itself, not true pathogenic heat. Observing that Zhang Zhongjing treats interior cold with warming herbs without addressing the external heat in such cases reveals his therapeutic intent. If urgent resolution of the exterior were truly indicated, would he not clearly state it after the interior harmonizes? Moreover, if Three Yin cold diseases were merely miscellaneous diseases, why are they recorded in the *Treatise on Cold Damage Diseases* to confuse later generations? Why do the clauses in the Jueyin chapter each begin with the word "Shanghan" (Cold Damage)?
The *Neijing* describes Three Yin diseases as uniformly heat, stating the norm. Zhang Zhongjing describes Three Yin diseases as including both cold and heat, stating the variation. They run parallel without contradiction. Later generations claiming cold damage originally has no cold syndromes fail to understand variation despite knowing the norm. However, those in the world who strictly adhere to the *Formulary of the Bureau* and favor warming agents can often preserve patients with cold syndromes without other issues. Their adherence is biased, but their treatment of this specific aspect is correct. If students of medicine understand that Three Yin diseases inherently include syndromes caused by cold pathogens, the original intent behind Zhang Zhongjing's created methods can be clearly understood, preventing deviation by other theories.
Someone asked: "Diseases of cold damage must involve constrained heat in Yang meridians before transmitting to Three Yin. Now you claim direct injury to Yin meridians leads to immediate entry and cold syndromes. What is your evidence?" I replied: "Based on Zhang Zhongjing. Zhang Zhongjing said: 'Diseases with fever and aversion to cold originate in Yang; diseases without fever and with aversion to cold originate in Yin. Those originating in Yang heal in seven days; those originating in Yin heal in six days.' Calling it 'no fever and aversion to cold' indicates it is not constrained heat in Yang meridians. Calling it 'originating in Yin' indicates it did not transmit from Yang meridians. Calling it 'heals in six days' indicates it did not start in Taiyang, but counting begins from the day the disease manifested in the Yin meridians." Zhang Zhongjing also said: "In cold damage, from one or two days to four or five days, if reversal cold occurs, fever must follow. If reversal cold lasts five days, fever also lasts five days. If on the sixth day reversal cold returns, but does not, the patient heals. If reversal cold lasts four days, fever lasts three days, and reversal cold returns for five days, the disease progresses." Getting cold damage without fever, presenting immediately with reversal cold, could this be caused by heat pathogens transmitting deeply? Nowadays, many people present with various cold syndromes from the onset, with no heat whatsoever. This is direct injury to Yin meridians and immediate entry. If one cannot fathom Zhang Zhongjing's mind but执 (clings) to the saying that all cold damage results in heat diseases for treatment, few will avoid premature death.