【纲】仲景曰。病有发热恶寒者。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。以阳数七。阴数六故也。
【目】许叔微曰。伤寒六七日。无热。脉沉紧而细。烦躁不饮水。此阴盛格阳也。当用附子霹
雳散。饮水者不可服。
吴绶曰。阴症似阳。乃水极似火也。盖伤寒传变。误服凉剂。攻热太速。其人素本肾气虚寒。
遂变阴症。冷盛于内。逼其浮阳之火发于外。面赤烦躁。身微热。渴欲饮而不能饮。大便秘。小便
淡黄。或呕逆气促、郑声、咽喉痛。所以状似阳症。如妄投寒凉即死。切其脉沉细微迟者。急用通
脉四逆汤。倍参、附以接真阳。设或差迟。则阴盛阳衰。参、附亦不救矣。此与阴盛格阳例同。王太仆
所谓身热脉数。按之不鼓击者。名阴盛格阳。非热也。阳症似阴。乃火极似水也。盖伤寒热甚。失
于汗下。阳气亢极。郁伏于内。反见胜己之化于外。故身寒逆冷。神气昏昏。状若阴症也。大抵唇
焦舌燥。渴饮便秘。溺赤涩。设有稀粪水利出者。此内有燥屎结聚。乃旁流之物。非冷利也。再审有
失气极臭者。是也。脉虽沉。切之必滑有力。或时躁热。不欲衣被。扬手掷足。谵语。此阳症也。
轻者。人参白虎汤。或小柴胡合解毒汤。内实者。调胃承气汤。潮热者。大柴胡汤加芒硝。若大实
大满。秘而不通。大承气汤。必审轻重而酌用之。此与阳盛拒阴亦同。王太仆所谓病患身寒厥冷。
其脉滑数。按之鼓击指下者。名阳盛拒阴。非寒也。
赵嗣真曰。仲景论阴虚阳盛。阳虚阴盛。理实深奥。经曰。邪气甚则实。精气脱则虚。因正气
先虚以致邪气客之而为盛实。于是有阴虚阳盛阳虚阴盛之别。愚因括仲景之理而详说之。盖盛指
邪气言。虚指正气言。阴阳虚盛。邪正消长之机也。且正气在人。阳主表而阴主里。邪气中人。表为阴
而里为阳。若表之真阳先虚。故阴邪乘阳而盛实。表受
邪者。阳虚也。脉浮紧。阴邪盛于外也。是谓阳虚阴盛。所以用桂枝辛甘之温剂。汗之则阴邪消。
温之则真阳长。使邪去正安。故愈。又若里之真阴先虚。故阳邪入阴而盛实。里受邪者。阴
虚也。脉沉实者。阳邪盛于内也。是谓阴虚阳盛。所以用承气峻苦之寒剂。下之则阳邪消。寒之则
真阴长。邪去正安。故愈。以是知仲景主此二症。盖一指表症。一为里症。指邪正消长而言。
非兼言表和里病。里和表病。而谓之阴阳虚盛也。况和者。无病也。以和训虚。恐碍理。
李梃曰。概言之。三阳经病。即阳症。手之三阳。从头走足。故头疼身热云云。三阴经病。即阴症。足之三阴。从
足走腹。故腹痛自利云云。然阴阳俱有表里二症。阳症表里同归于热而已。阴症表郁似阳。入里则有
传经直中之殊。大抵阳症之表。发热恶寒。清便自调。面光声亮。鼻息如常。手足温。阳症之里。
唇焦舌燥。爪甲红活。身轻易转。烦渴。掀衣。扬手掷足。大便硬闭。小便赤涩。脉浮洪数。用汗
吐下和四法以治之。阴症之表。无热恶寒。面惨声短。鼻息气冷。手足厥逆。阴症之里。唇紫舌卷。
爪甲青黑。身重难转。不渴。引衣。卧多蜷足。大便泄利。小便清白。脉细沉微。每与阳症相反。
盖阳症自上而下。故初起有头疼。阴症则无也。阳症自外传入。故郁而为热。阴症则无热而反厥冷
也。阳症扬手掷足。阴症则卧多蜷足。阳症内热而渴。阴症则不渴。阳症二便闭。阴症则二便清且
利也。惟腹痛与呕。阴阳二症俱有。然阴脉沉微。凡言阳症。多得之风寒暑湿。邪生于太阳也。
凡言阴症。多得之起居饮食喜怒。邪生于少阴也。故云。伤寒挟内伤者。十居八九。此阴阳正病也。
阳邪不深。不能至于厥逆。阴邪不甚。不能至于烦躁。此水极似火。火极似水。谓之反化。亢
极则害之义也。阳症潮汗秘赤满渴狂谵。甚则斑血喘急。然热极忽然热伏于内。故身寒四肢厥
逆。状若阴症。但身虽冷而不欲近衣。神虽昏而气色光润。脉必沉滑而有力。此阳极似阴也。宜大
柴胡下之。或白虎汤、竹叶石膏汤。阴症厥冷吐利不渴静蜷。甚则咽痛郑声。然寒极忽然火浮于外。
发躁扰乱。状若阳症。然身虽烦躁。而引衣自盖。口虽燥渴而饮水不下。脉必沉细无力。此阴极
似阳也。宜通脉四逆汤。从治者。反攻也。热药冷冻饮料。冷药热饮。或
热药为君。而佐以凉药。或冷药为君。而佐以热药。亦非判然如庸医之差误也。借有热病服热药而愈
者。必先服寒药过多。寒病服寒药而愈者。必先服热药过多故耳。若夫以寒治热。以热治寒。此为逆
治。逆治者。正治也。正治之法。人孰不知之乎。
张介宾曰。凡治伤寒。须先辨阴阳二症。若病自三阳。不能解散。而传入三阴。则寒郁为热。因成阳症。盖其初病。
必发热头痛。脉浮紧。无汗。以渐而深。乃入阴经。此邪自阳分传来。愈深则愈入。虽则阴经。亦阳症也。脉必沉实有
力。其症必烦热炽盛。此当攻里。或清或下。随宜而用。若内不热。安得谓阳症乎。若初起本无发热头疼等症。原不由
阳经所传而竟入阴分者。其症或厥冷。或呕吐。或腹痛泻利。或畏寒不渴。或脉来沉弱无力。此皆元阳元气不足。乃为
真正阴症。经曰。发热恶寒发于阳。无热恶寒发于阴。此以传经不传经而论阴阳也。阴阳之治。又当察其虚实如下。治
伤寒。凡阳症宜凉宜泻。阴症宜补宜温。此大法也。但以经脏言阴阳。则阴中本有阳症。此传经之热邪也。以脉症言阴
阳。则阳中最多阴症。此似阳之虚邪也。惟阴中之阳易辨。而阳中之阴难知。如发热狂躁。口渴。心烦喜冷。饮水无度。
大便硬。小便赤。喉痛口疮。身粗气急。脉滑实有力者。此真正阳症也。其有身虽热。而脉来微弱无力者。此虽外症似
阳。实非阳症。陶节庵云。凡发热面赤。烦躁揭衣。唇口赤裂。言语善恶。不避亲疏。虚狂假斑。脉大者。人皆误认阳
症。殊不知阴症。不分热与不热。须凭脉下药。至为切当。不问脉之浮沉大小。（亦是切脉要诀）但指下无力。重按则无。
便是阴脉。不可与凉药。服之必死。急与五积散通解表里之寒。甚者必加姜、附。又曰。病自阳分传入三阴者。俱是脉
沉。须以指下有力无力为辨。（切脉要诀）有力者为阳为热为实。无力者为阴为虚为寒。此节庵出人之见也。然以余观之。
似阳非阳之症。不必谓其外热烦躁。微渴戴阳之类。即皆为阴症也。但见其元阳不足。而气虚于中。虽有外热。亦假热
耳。设用清凉消耗。则中气愈散。中气既败。则邪气愈强。其能生乎。
【纲】张仲景说：疾病出现发热且恶寒的，是发于阳经；不发热而只恶寒的，是发于阴经。发于阳经的，七日可愈；发于阴经的，六日可愈。这是因为阳的成数是七，阴的成数是六的缘故。
【目】许叔微说：伤寒病到了六七天，没有发热，脉象沉紧而细，烦躁但不想喝水，这是阴盛格阳（阴寒内盛，逼迫阳气浮越于外）的证候。应当使用附子霹雳散。如果患者想喝水，则不可服用此方。
吴绶说：阴症似阳，乃是水极似火的表现。大概是因为伤寒传变过程中，误服了凉药，清热攻下太过迅速，导致患者原本肾气虚寒，于是转变为阴症。体内寒气极盛，逼迫浮游的阳气之火发散于体表，出现面红、烦躁、身体微热、口渴想喝水却喝不下、大便秘结、小便淡黄，或者呕吐逆气、气促、语言错乱（郑声）、咽喉痛等症状，所以症状看起来像阳症。如果妄用寒凉药物就会致死。切诊发现脉象沉细微迟的，必须紧急使用通脉四逆汤，并加倍人参、附子的用量以接续真阳。如果延误时机，导致阴盛阳衰，即使用人参、附子也无法挽救了。这与阴盛格阳的例子相同。王太仆所说的身热脉数，但按之无力、不鼓击指下的，名为阴盛格阳，并非真正的热证。阳症似阴，乃是火极似水的表现。大概是因为伤寒热势极盛，失于发汗或攻下，阳气亢盛至极，郁伏于体内，反而在体表表现出克制自身的五行之气（寒化），因此出现身寒、四肢逆冷、神志昏沉，症状好像阴症一样。大体上，嘴唇焦裂、舌头干燥、口渴饮水、大便秘结、小便赤涩，如果有稀粪水样便排出，这是体内有燥屎结聚，属于“热结旁流”之物，并非冷性泄泻。再观察如果有极其臭秽的放屁，就是这种情况。脉象虽然沉，但切之必然滑利有力，或者时而躁热，不想穿衣盖被，扬手掷足，胡言乱语，这是阳症。轻症的，用人参白虎汤，或小柴胡汤合解毒汤。内有实邪的，用调胃承气汤。有潮热的，用大柴胡汤加芒硝。如果是大实大满，秘结不通，用大承气汤。必须审察轻重而酌情使用。这与阳盛拒阴也是相同的道理。王太仆所说的病患身寒厥冷，但其脉滑数，按之鼓击指下的，名为阳盛拒阴，并非真正的寒证。
赵嗣真说：张仲景论述阴虚阳盛、阳虚阴盛的道理，确实深奥。《内经》说：邪气盛则实，精气夺则虚。因为正气先虚，导致邪气乘虚而入而表现为盛实，于是有了阴虚阳盛和阳虚阴盛的区别。我概括张仲景的理论并详细解说它。大概“盛”是指邪气，“虚”是指正气，阴阳的虚实盛衰，是邪正消长的机理。况且正气在人体内，阳主表而阴主里；邪气侵犯人体，表为阴而里为阳。如果体表的真阳先虚，那么阴邪就会乘虚而入而盛实，这就是表受邪，属于阳虚。脉象浮紧，说明阴邪盛于体表，这叫做阳虚阴盛。所以要用桂枝汤等辛甘温的药物，通过发汗使阴邪消退，通过温补使真阳生长，使邪去正安，所以痊愈。另外，如果体内的真阴先虚，那么阳邪就会入里而盛实，这就是里受邪，属于阴虚。脉象沉实，说明阳邪盛于体内，这叫做阴虚阳盛。所以要用承气汤等峻猛的苦寒药物，通过攻下使阳邪消退，通过寒凉使真阴生长，邪去正安，所以痊愈。由此可知，张仲景主治这两种证候，一个指表症，一个指里症，是从邪正消长的角度而言的，并不是兼谈表和里病、里和表病而称之为阴阳虚盛。况且“和”是指无病，用“和”来解释“虚”，恐怕违背医理。
李梃说：概而言之，三阳经的病，就是阳症。手三阳经从头走足，所以有头疼、身热等症状。三阴经的病，就是阴症。足三阴经从足走腹，所以有腹痛、自利（自发性腹泻）等症状。然而阴阳都有表里两种证候，阳症的表里都归结为热而已。阴症的表证郁滞似阳，入里则有传经和直中的不同。大体上，阳症的表证，发热恶寒，大小便正常，面色光亮，声音洪亮，呼吸如常，手足温暖。阳症的里证，嘴唇焦裂，舌头干燥，指甲红润鲜活，身体轻便易转动，烦渴，掀开衣服，扬手掷足，大便硬结闭塞，小便赤涩，脉象浮洪数。用汗、吐、下、和四种方法来治疗。阴症的表证，无热恶寒，面色惨淡，声音短促，鼻息气冷，手足厥冷。阴症的里证，嘴唇紫暗，舌头卷缩，指甲青黑，身体沉重难转动，不口渴，喜欢裹衣，睡觉多蜷缩双脚，大便泄泻，小便清白，脉象细沉微。往往与阳症相反。大概阳症自上而下发展，所以初起有头疼，阴症则没有。阳症自外传入，所以郁积而为热，阴症则无热反而厥冷。阳症扬手掷足，阴症则睡觉多蜷缩双脚。阳症内热而渴，阴症则不渴。阳症二便闭结，阴症则二便清利。只有腹痛和呕吐，阴阳两症都有。然而阴脉沉微。凡是说阳症，多因感受风、寒、暑、湿所致，邪气生于太阳经。凡是说阴症，多因起居饮食、喜怒情绪所致，邪气生于少阴经。所以说，伤寒夹杂内伤的，十有八九。这是阴阳的正病。阳邪不深，不能至于厥逆；阴邪不甚，不能至于烦躁。这就是水极似火、火极似水，称为反化，也就是亢极则害的道理。阳症有潮汗、便秘、尿赤、腹胀、口渴、狂躁、谵语，甚至发斑、出血、喘急。然而热极忽然热伏于内，所以身寒、四肢厥冷，状若阴症，只是身体虽冷却不欲近衣，神志虽昏但气色光润，脉必沉滑而有力，这是阳极似阴。宜用大柴胡汤攻下，或用白虎汤、竹叶石膏汤。阴症有厥冷、呕吐、泄利、不渴、静卧蜷缩，甚至咽痛、郑声。然而寒极忽然火浮于外，发生烦躁扰乱，状若阳症，然而身体虽烦躁却引衣自盖，口虽燥渴却饮水不下，脉必沉细无力，这是阴极似阳。宜用通脉四逆汤。从治者，即反攻之法。热药冷服，冷药热服，或以热药为主佐以凉药，或以冷药为主佐以热药，这也不是像庸医那样截然错误的差别。借如有热病服热药而愈的，一定是先前服寒药过多；有寒病服寒药而愈的，一定是先前服热药过多罢了。至于用寒治热，用热治寒，这叫逆治。逆治，其实就是正治。正治的方法，谁不知道呢？
张介宾说：凡是治疗伤寒，必须先辨别阴阳两症。如果病自三阳经而来，不能解散，而传入三阴经，则寒郁化为热，因而成为阳症。大概其初起时，必定发热、头痛、脉浮紧、无汗，逐渐深入，乃进入阴经。这是邪气自阳分传来，越深入越进入阴经，虽然是阴经，也属于阳症。脉必沉实有力，症状必定烦热炽盛。这应当攻里，或清或下，随宜而用。如果内部不热，怎么能叫阳症呢？如果初起本来就没有发热、头疼等症状，原本不是由阳经传来而竟直接入阴分的，其症状或厥冷，或呕吐，或腹痛泄利，或畏寒不渴，或脉来沉弱无力。这都是元阳、元气不足，才是真正的阴症。《内经》说：发热恶寒发于阳，无热恶寒发于阴。这是以是否传经来论断阴阳的。阴阳的治疗，又应当察其虚实如下。治疗伤寒，凡是阳症宜凉宜泻，阴症宜补宜温，这是大法。但如果以经络脏腑言阴阳，则阴经中本有阳症，这是传经的热邪。如果以脉症言阴阳，则阳症中最多阴症，这是似阳的虚邪。只有阴中之阳容易辨别，而阳中之阴难以知晓。如发热、狂躁、口渴、心烦喜冷、饮水无度、大便硬、小便赤、喉痛口疮、身体粗糙气急、脉滑实有力的，这是真正的阳症。其中有身体虽热，但脉来微弱无力的，这虽然外表症状似阳，实际上并非阳症。陶节庵说：凡是发热面赤、烦躁揭衣、唇口赤裂、言语善恶不分、不避亲疏、虚狂假斑、脉大的，人们都误认为是阳症，殊不知是阴症。不论热与不热，必须凭脉下药，极为恰当。不问脉的浮沉大小（这也是切脉的要诀），只要指下无力，重按则无，便是阴脉，不可给予凉药，服之必死。急用五积散通解表里之寒，严重的必须加生姜、附子。又说：病自阳分传入三阴的，俱是脉沉，必须以指下有力无力来辨别（切脉要诀）。有力者为阳、为热、为实，无力者为阴、为虚、为寒。这是节庵超出常人的见解。然而依我看来，似阳非阳的症候，不必说其外热、烦躁、微渴、戴阳之类，就都是阴症。只要见到其元阳不足，而气虚于中，虽然有外热，也是假热。如果使用清凉消耗，则中气更加涣散，中气既然败坏，则邪气更加强盛，还能生存吗？
[General Principle] Zhang Zhongjing stated: When a disease presents with fever and aversion to cold, it originates from the Yang aspect. When there is no fever but only aversion to cold, it originates from the Yin aspect. Diseases originating from Yang typically resolve in seven days, while those originating from Yin typically resolve in six days. This is because the complete number for Yang is seven, and for Yin is six.
[Detailed Discussion] Xu Shuwei stated: In typhoid (Shanghan) disease, if after six or seven days there is no fever, the pulse is deep, tight, and thin, accompanied by irritability but no desire to drink, this indicates Yin excess repelling Yang (Yin Cheng Ge Yang). The Fuzi Pili San (Aconite Thunderbolt Powder) should be used. If the patient desires to drink, this formula must not be administered.
Wu Shou stated: Yin syndrome resembling Yang is essentially water at its extreme resembling fire. Generally, due to the transmission of typhoid, if cooling agents are mistakenly taken, clearing heat and purging too rapidly, and the patient's constitution is originally deficient and cold in Kidney Qi, it transforms into a Yin syndrome. Extreme cold within forces the floating Yang fire to manifest externally, causing redness of the face, irritability, slight body heat, thirst with an inability to drink, constipation, pale yellow urine, or vomiting, reverse flow of Qi, shortness of breath, Zhengsheng (slurred speech), and sore throat. Thus, the presentation resembles Yang syndrome. Administering cold and cooling herbs recklessly will lead to death. If the pulse is felt to be deep, fine, slow, and weak, Tongmai Sini Tang (Pulse-Returning Decoction) must be urgently administered, with doubled doses of Renshen (Ginseng Root) and Fuzi (Prepared Aconite Root) to reconnect True Yang. If treatment is delayed, leading to Yin excess and Yang decline, even Renshen and Fuzi cannot save the patient. This is similar to the case of Yin excess repelling Yang. Wang Taipu described that when the body is hot and the pulse rapid, but upon pressure does not strike the fingers forcefully, it is named Yin excess repelling Yang, which is not true heat. Conversely, Yang syndrome resembling Yin is essentially fire at its extreme resembling water. Generally, when typhoid heat is severe and sweating or purging is neglected, Yang Qi becomes hyperactive and extreme, stagnating internally, and manifests externally as the transformation that overcomes itself (cold transformation). Thus, the body feels cold, limbs are reversedly cold, and spirit is lethargic, resembling Yin syndrome. Generally, cracked lips, dry tongue, thirst, constipation, and dark scanty urine indicate internal dryness. If loose watery stool passes, this is "dryness accumulation with peripheral flow" caused by accumulated dry feces inside, not cold diarrhea. Furthermore, extremely foul flatulence confirms this. Although the pulse may be deep, it must feel slippery and forceful upon palpation. Occasional restlessness, desire to discard clothing, throwing hands and feet about, and delirious speech indicate Yang syndrome. For mild cases, Renshen Baihu Tang (Ginseng White Tiger Decoction) or Xiao Chaihu Tang (Minor Bupleurum Decoction) combined with Jiedu Tang (Detoxification Decoction) can be used. For internal excess, Tiaowei Chengqi Tang (Regulating Stomach and Purging Intestines Decoction) is indicated. For tidal fever, Da Chaihu Tang (Major Bupleurum Decoction) with Mangxiao (Mirabilite) is used. For severe fullness and blockage without passage, Dachengqi Tang (Major Purging Decoction) is required. One must assess severity and use appropriately. This is also consistent with Yang excess rejecting Yin. Wang Taipu described that when a patient has cold body and厥逆 (reversed cold limbs), but the pulse is slippery and rapid, striking the fingers forcefully upon pressure, it is named Yang excess rejecting Yin, which is not true cold.
Zhao Sizhen stated: Zhang Zhongjing’s discussion on Yin deficiency with Yang excess, and Yang deficiency with Yin excess, is profound. The Classics state: "Excess of pathogenic factors constitutes Shi (Excess); depletion of essential Qi constitutes Xu (Deficiency)." Because Righteous Qi (Zheng Qi) is first deficient, allowing pathogenic factors to invade and manifest as excess, distinctions arise between Yin deficiency/Yang excess and Yang deficiency/Yin excess. I summarize Zhongjing’s theory and elaborate. "Excess" refers to pathogenic factors; "deficiency" refers to Righteous Qi. The fluctuation of Yin-Yang deficiency/excess is the mechanism of pathogen vs. righteousness growth/decline. Righteous Qi resides in the person: Yang governs the exterior, Yin governs the interior. Pathogens invade: the exterior is Yin, the interior is Yang. If True Yang of the exterior is initially deficient, Yin pathogens invade and become excessive, constituting exterior invasion characterized by Yang deficiency. The pulse is floating and tight, indicating Yin pathogens excessive on the outside; this is called Yang deficiency with Yin excess. Therefore, Guizhi Tang (Cinnamon Twig Decoction) and other acrid-sweet-warm formulas are used to induce sweating to eliminate Yin pathogens and warm to nourish True Yang, ensuring pathogens depart and righteousness is secure, leading to recovery. Conversely, if True Yin of the interior is initially deficient, Yang pathogens enter and become excessive, constituting interior invasion characterized by Yin deficiency. The pulse is deep and solid, indicating Yang pathogens excessive inside; this is called Yin deficiency with Yang excess. Therefore, Chengqi Tangs and other bitter-cold purgatives are used to purge Yang pathogens and cool to nourish True Yin, ensuring pathogens depart and righteousness is secure, leading to recovery. Thus, Zhongjing treats these two syndromes: one refers to exterior syndromes, the other to interior syndromes, speaking from the perspective of pathogen/righteousness dynamics, not merely combining exterior harmony/interior disease or vice versa. Moreover, "harmony" implies absence of disease; interpreting "deficiency" as "harmony" contradicts theory.
Li Ting stated: Generally, diseases of the Three Yang meridians are Yang syndromes. Hand-Taiyang, Shaoyang, and Yangming move from head to foot, hence headaches and body heat. Diseases of the Three Yin meridians are Yin syndromes. Foot-Taiyin, Shaoyang, and Taiyin move from foot to abdomen, hence abdominal pain and spontaneous diarrhea. However, both Yin and Yang have exterior and interior presentations. Yang syndromes' exterior and interior both归结 to heat. Yin syndromes' exterior stagnation resembles Yang, while interior transmission differs between meridian transmission and direct attack. Generally, Yang syndrome exterior: fever, aversion to cold, normal urination/defecation, bright complexion, loud voice, normal respiration, warm hands/feet. Yang syndrome interior: cracked lips, dry tongue, ruddy nails, ease of movement, irritability/thirst, discarding clothes, thrashing limbs, hard constipation, dark scanty urine, floating/hyperactive/rapid pulse. Treat with sweating, emesis, purging, and harmonizing methods. Yin syndrome exterior: no fever, aversion to cold, pale/dull complexion, short voice, cold breath, cold/reversed limbs. Yin syndrome interior: purple lips, curled tongue, cyan/black nails, heavy body difficult to turn, no thirst, desire to cover up, sleeping curled up, diarrhea, clear urine, deep/fine/weak pulse. These often oppose Yang syndromes. Yang syndromes proceed from top to bottom, hence initial headache; Yin syndromes do not. Yang syndromes transmit from outside, hence stagnate into heat; Yin syndromes have no heat but reversed cold. Yang syndromes thrash limbs; Yin syndromes sleep curled. Yang syndromes have internal heat and thirst; Yin syndromes have no thirst. Yang syndromes have closed urination/defecation; Yin syndromes have clear/loose urination/defecation. Only abdominal pain and vomiting occur in both. However, Yin pulse is deep/weak. Yang syndromes generally result from Wind-Cold-Heat-Dampness pathogens affecting Taiyang. Yin syndromes generally result from lifestyle/diet/emotion pathogens affecting Shaoyin. Thus, typhoid complicated by internal injury accounts for eight or nine out of ten cases. This is the correct pathology of Yin and Yang. Yang pathogens not deep enough cannot cause reversed cold; Yin pathogens not severe enough cannot cause irritability. This is "water extreme resembling fire, fire extreme resembling water," called counter-transformation, meaning extreme exuberance causes harm. Yang syndromes include tidal sweating, constipation, dark urine, fullness, thirst, mania, delirium, even macules, bleeding, asthma. However, extreme heat suddenly hiding internally causes cold body and reversed limbs, resembling Yin syndrome, yet the body is cold but does not desire covering, spirit is confused but complexion is lustrous, pulse is deep/slippery/forceful; this is Yang extreme resembling Yin. Use Dachengqi Tang to purge, or Baihu Tang/Zhuye Shigao Tang. Yin syndromes include reversed cold, vomiting, diarrhea, no thirst, quiet curling, even sore throat/Zhengsheng. However, extreme cold suddenly causing fire to float externally causes irritability/restlessness, resembling Yang syndrome, yet body is irritable but covers self, mouth is dry/thirsty but cannot swallow water, pulse is deep/fine/weak; this is Yin extreme resembling Yang. Use Tongmai Sini Tang. Congzhi (Following Treatment) is counter-attack. Hot medicine taken cold, cold medicine taken hot, or hot medicine as sovereign with cold minister, or cold medicine as sovereign with hot minister, is not a mistake like that of mediocre physicians. If a heat disease cures with hot medicine, it is because cold medicine was previously overdosed; if a cold disease cures with cold medicine, it is because hot medicine was previously overdosed. Using cold to treat heat, and heat to treat cold, is called Nizhi (Reverse Treatment). Nizhi is actually Zhengzhi (Correct Treatment). Who does not know the method of Correct Treatment?
Zhang Jiebin stated: In treating typhoid, one must first distinguish Yin and Yang syndromes. If disease originates from Three Yang, fails to disperse, and transmits to Three Yin, cold stagnates transforming into heat, becoming a Yang syndrome. Initially, there must be fever, headache, floating/tight pulse, and anhidrosis, gradually deepening into Yin meridians. This is pathogen transmitting from Yang division; deeper penetration means entering Yin, yet it remains a Yang syndrome. Pulse is deep/solid/forceful; symptoms are intense irritability/heat. This requires purging the interior, either clearing or purging, as appropriate. If interior is not hot, how can it be Yang syndrome? If initially there is no fever/headache, not transmitted from Yang meridians but directly entering Yin division, symptoms may include reversed cold, vomiting, abdominal pain/diarrhea, aversion to cold/no thirst, or deep/weak/pulseless. These are all Yuan Yang/Essential Qi insufficiency, constituting true Yin syndrome. The Classics state: "Fever with aversion to cold originates from Yang; no fever with aversion to cold originates from Yin." This distinguishes Yin/Yang based on transmission. Treatment of Yin/Yang must observe deficiency/excess. General rule: Yang syndromes require cooling/purging; Yin syndromes require tonifying/warming. However, discussing Yin/Yang by meridians/organs, Yin meridians contain Yang syndromes (transmitted heat). Discussing by pulse/symptoms, Yang syndromes contain many Yin syndromes (Yang-resembling deficiency pathogens). Yin-within-Yang is easy to identify; Yang-within-Yin is difficult. Fever, mania, thirst, vexation preferring cold, excessive drinking, hard stool, dark urine, sore throat/mouth ulcers, rough body/rapid breathing, slippery/solid/forceful pulse constitute true Yang syndrome. If body is hot but pulse is weak/forceless, although exterior resembles Yang, it is not true Yang. Tao Jian'an said: Fever, red face, irritability, discarding clothes, cracked lips/mouth, erratic speech, ignoring kinship, false macules, large pulse are mistaken for Yang syndrome but are Yin syndrome. Regardless of heat presence, rely on pulse. Whether pulse is floating/deep/large/small, if forceless on finger and empty on heavy pressure, it is Yin pulse; do not give cooling medicine, or death ensues. Urgently use Wuji San (Five Accumulations Powder) to resolve exterior-interior cold, adding Shengjiang (Fresh Ginger) and Fuzi for severe cases. Also, diseases transmitting from Yang to Three Yin all have deep pulses; distinguish by forcefulness. Forceful is Yang/Heat/Excess; forceless is Yin/Cold/Deficiency. This is Tao’s insight. However, I view that Yang-resembling-non-Yang syndromes, such as external heat, irritability, slight thirst, Daiyang (floating Yang), are not all Yin syndromes. If Yuan Yang is insufficient and Qi is deficient internally, external heat is false heat. Using cooling/consuming methods scatters Middle Qi further; once Middle Qi fails, pathogens strengthen, and survival is impossible.