三阴三阳者，阳经为阳，阴经为阴，此以外言之也；五脏为阴，六腑为阳，此以内言之
也。
在外者，又以寒伤营，在脉中者为阴；风伤卫，在脉外者为阳。在内者，六腑又以胃为阳，
大肠为阴，膀胱为阳，小肠为阴，胆为更阴也；五脏又以肺为阳，心、脾为阴，肝、肾为至
阴也。《内经》以脾为至阴。
三阳亦有里证，三阴亦有表证。在表者，无论阴阳，多在足经见证，在里则手足俱有矣
。阳
明承气，攻大肠非攻胃也，岂有燥屎而在胃耶?太阳抵当，攻小肠，非攻膀胱也；膀胱果有
蓄血，当如血淋，而小便不利矣，何得小便利而反大便黑耶?且其证兼见昏昧、谵妄如狂者
，心证也；心与小肠脉络相通，故气相通也。
陶节庵谓∶伤寒至沉脉，如分阴阳。意谓邪在三阳之经者，脉皆浮也。至脉沉，则有三
阳之里，
与三阴之经矣。然浮而无力无神，乃阴虚之极，比邪陷于里，以致里实者，更属危险。张景
岳重论此义，最为有功，正不得谓阴脉皆沉，而浮必无阴也。
三阴皆有吐利、四肢逆冷证。盖邪入三阴，非遽入脏也，必先动于腑。寒邪在腑，故变
见诸证，若动脏，即死矣。《灵枢》曰∶邪中于阴，则
溜于腑，是也。且吐属胃，利属大肠，四肢属脾，故邪入三阴，最重脾胃，脾胃不败，邪虽
入里，易治也。
胆为清净之腑，无出无人，故禁三法。然所谓足少阳证者，以其经也，经气岂无出入耶
?若
入里，则不必在胆，而在三焦矣。三焦属气，虽不似抵当、承气之有形可攻，而升降调气之
法，于胆犹远，于三焦最切，故大柴胡亦加入攻药者，为三焦设也。故丹溪《脉因证治》谓
少阳禁三法，亦宜三法。
三阴下利，与阳明之燥实对看。三阴大便寒实，即为阴结，三阳下利，即为协热。然则
岂无寒利耶?曰∶寒利即三阴也。
外淫有六，而仲景以伤寒名论。方中行、张隐庵必以三阴三阳属于六气，大谬。谓讲明
此书之理，即通于治六气则可耳!然自古及今，未见有此通人也。
伤寒邪在表，则分六经；入里，则亦分三焦。吴鞠通谓温病分三焦，伤寒亦何独不分三
焦?是矣。而不言在表在里，语欠分晓。
少阴一经，赅左右肾，为水火同居。寒邪与水合气，而火为所抑，故脉沉细，但欲寐，
阳抑
而不得伸也；火抑而又常欲伸，故常有心烦欲吐之象也。或曰少阴入里，即通于心，其心烦
者
，非即心证耶?不知寒邪果入心，必至昏迷不寤矣，何得尚有烦也?其心烦者，乃下元真火为
寒邪所抑，不得抒发，但能一线直上，以扰包络之气也。
心不受邪，惟少阴一经不入手，以手厥阴心包络代之。包络者，心之外宫城也。妇人热
入血
室之证，即男子热入心包之证，验之屡矣。仲景于热入血室，治以小柴胡。叶天士于此证，
独忌柴胡，非无见也。徐灵胎讥之，未免孟浪。细思此证，与小柴胡何涉?仲景此方，盖治
少阳之热感于心包者，热入心包，身静不欲动，神昏谵语，其邪气实者，亦或躁扰如狂，皆
热证也。何以无寒入心包络证也?盖心包虽代心君受邪，究为纯火之脏，与神明之主只隔一
间，若寒水贼邪上犯，必是火衰神去，其窜入心脏，致人于死，顷刻间事。故中寒伤心
之
证，其死极速，不及施救。伤寒之邪，不及中寒之猛，不得遽入心包，必待化热而后熏蒸渐
渍，同气相召矣。故有热入血室，无寒入血室；有热入心包，无寒入心包也。非无也，有之
则死。如吐利、恶寒、身蜷、四逆、烦躁，即心阳之渐熄也，而况其卒中者耶!
大便闭结，亦有潮热、谵语、神昏不识人之证，全与热犯心包无异者，以其皆是热在血
分也
。当以脉辨之∶心包热者，左寸脉必缓而滑；大便闭者，右尺脉必长而实也。又少阴病，咳
而下利，谵语者，以火劫汗故也，小便必难；又伤寒脉浮，以火劫汗，惊狂，起卧不安者，
救
逆汤主之。此二者，皆强汗亡阳之证。汗为心液，心液虚，不能养神故也。大抵谵语，总属
于心神迷乱之所致，但有邪气正在包络者，有邪气感动包络者，邪之虚实不同，病之微甚有
别。即如肝乘脾，腹满，谵语，寸口脉沉而紧，名曰纵，刺期门，亦以邪气有与心相感者也
。
伤寒传经，有此经之邪延及彼经者，有前经之邪移及后经者。合病、并病，皆邪气实至
于其
经也。更有邪在此经，而兼见彼经之证者；邪在阳经，而兼见阴经之证者。邪气未入，证何
由见?盖人身经络相通，一气相感，虽有界畔，终难板分。如少阳病，脉浮大，上关上，但
欲眠睡，合目则汗，此少阴心证也，心气不任少阳之疏泄而然也。此气之所感，非邪由少阳
已入心也。他经此类甚多。气相感者，大抵寒从寒、热从热，寒多感于肺、肾，热多感于心
、肝，所谓同气相求也。其与传经证候，虚实微甚之间，自有辨别。有先感而邪因传之者，
有先感而邪亦终不传之者，前人于传经之说，刺刺不休，皆未发明及此，岂以浅不足道耶?
王勋臣极诋分经之谬，是又但知气之相感，而未知有形之邪气，固各有界畔也。
《伤寒》、《金匮》中，每为死证立方，此义最可思。
伤寒有证异而治同，如自利不渴属太阴，自利而渴属少阴，皆用四逆温之；有证同而治
异，
如阳明自利，腹痛者，此内实也，宜下之；太阴为病，下之则胸下结硬矣。究竟同者必有
其所以同，少阴渴而用四逆者，以其小便色白，下焦虚寒，太阴不渴，亦以其脏寒也；异者
必有其所以异，腹痛宜下不宜下，一能食，一不能食也。读书须从此等处，用心参校，自有
会悟，然必先逐条熟读，方可如此；否则抛荒本义，彼此错综，徒乱人意。
尝读《至真要论》所谓胜至，报气屈伏而未发也。因思凡治胜气，必宜顾忌复气，不可
太过
，反助伏气为患也。不然，复已而胜，宁有止期耶?伤寒诸方，有寒热合用、咸辛酸苦并投
者，虽曰对证施治，亦未始非顾虑复气之微意也。六经复气，少阳、厥阴二经最甚。《内经
》所谓火燥热也。又曰木发无时，水随火也。汗则伤阳，阴盛者寒起矣；下则伤阴，阳盛者
热生矣。且或汗之而阳愈炽，下之而阴愈深，以汗药多热，下药多寒也。大法∶如火胜治
以咸，必佐以甘酸，咸者正治，甘为子气，导其去路，所谓泻之，酸为母法，护其根基，防
本气受制之太过也；火之复为水，甘以制水，而酸又泄水矣，故火淫所胜，以酸复之。王注
云∶不复其气，则淫气空虚，招其损矣。厥旨精微，读《伤寒》者，必须透此。
治病必求其本。所谓本者，有万病之公本，有各病之专本。治病者当求各病专本，而对
治之
，方称精切。薛立斋一流，专讲真水、真火，特治公本者耳!《伤寒》、《金匮》乃真能见
病治病，故药味增损，确切不移。读者每于一方药味，须一一从本证来源去路、本经虚实、
子母本气、标本胜复上，委曲搜求，确有见地，如自己出，他日自能独出手眼，无俟扶墙摸
壁，岂非快事!
凡读成方，须先揣摹方前所列之证，再看方中药味主对，如有不协于心，尽可拟改旁注
，以
俟异日考正。《伤寒》、《金匮》中，有许多今人不能遵用之方，向来注者，皆循例解说，
甚或穿凿，求深反浅；惟舒驰远能不讳所疑，然不自任不知，而必诋古人传误，未免讪上。
实则谵语，虚则郑声。然谵语亦有虚实。实者，阳明腑实证，协热下利证，热入血室证
，太
阳蓄血证；虚者，如过汗亡阳，过下亡阴，《内经·评热论》所谓汗出不衰，狂言失志者，
皆是。乃五脏之津液干枯，脏体燥热，神无所养也。经曰∶津液相成，神乃自生。津虚，故
神愦也。郑声者，邪声也。旧解谓郑重也，尾声重浊。此实也，非虚也。凡气虚者，发语之
始，其声如常，及其中、末，气有不续，声忽转变如他人，语不似其人平日之本声，故曰邪
也。
六经篇首，皆列中风脉证一条，是借以衬明伤寒之脉证也。盖中风间有不挟寒者，而伤
寒则
必因于风，风力挟寒伤人，极重者为中寒，次为伤寒，轻即中风也。可见六经有中风表证，
即皆有伤寒表证。陶节庵直中之说，讵为杜撰?况《内经》更有中阳溜经，中阴溜腑之明文
耶!但风寒初伤在经络，虽属于阴，在病气仍属于表，其治法总不外温散。太阳篇中六经初
伤之证具在，可按而考也。
伤寒一病，初起多同于中风，死证多类于中寒。
《伤寒》一部书，只有寒死证，无热死证。白虎、承气，本非死证也。若温病，则反是
矣。
“反”字有数解∶不应也，却也，复也。如弱反在关，濡反在巅，只是语助，俗言却也
。当
不能食，而反能食，乃不应也。如得之，反发热，脉沉者，麻辛附子汤，谓既始得之，复有
发热表证，虽脉沉，亦宜汗法也。读者当随文生义，勿执一而例百。
《伤寒》全论外感，《金匮》亦有外证。不见一方用羌活者，何也?即风湿，亦只用麻
黄、薏苡、附子、白术、黄 、防己。
诸家皆言六经每篇有提纲，其后凡浑言某经病者，即某经提纲所列诸证也。然太阴病，
脉浮
者，可发汗，宜桂枝汤。若果腹满而吐，食不下，自利益甚，时腹自痛，纯属阴寒内证，可
仅据脉浮而用汗耶?此等更须参详，读书固不可执一而例百也。
寒极反热，热极反寒，此化气也，真假勿淆，前人辨之矣。至于所以反热、反寒之故，
讫无
发明。若谓寒邪在内，而逼人身之热气于外，似于寒极反热之义，未甚切矣。窃思寒极反热
者，若果外见面赤、唇红，尚是真阳外越，仅可谓之假热；惟外无热象，而燥渴索饮，漱水
不咽，小涩大秘，时下微溏，此乃阴寒内结，微阳欲熄，不能运化津液以潮于经络脏腑，所谓
水冷成冰之寒燥也，此真反热者矣。热极反寒者，若因腠理开泄，卫阳不固，尚是正气内怯
，仅可谓之假寒；惟热邪涌盛，奔逸于经络脏腑之中，内外津液全为灼干，气管全为槁涩，
热邪奔迫不利，如人之疾趋而蹶者，壅积而不得四达，此真反寒者矣。前人于此等治法，每
以回阳泄热，约略立言。殊不知治假热者，引火归元；治反热者，温化津液。岂可固耶?治
假寒者，生津益气。治反寒者，生津泄气∶岂可同耶?假寒、假热，为虚气之游行，犹有此
二气也。反寒、反热，为虚象之疑似。其寒也，正其热之极；其热也，正其寒之极也。
三阴三阳，从体表经络而言，阳经属阳，阴经属阴；从体内脏腑而言，五脏属阴，六腑属阳。
在体表的层面，又以寒邪伤及营气（运行于脉中的气血），脉中之血为阴；风邪伤及卫气（运行于脉外的阳气），脉外之气为阳。在体内的层面，六腑中以胃为阳，大肠为阴，膀胱为阳，小肠为阴，胆更为阴；五脏中以肺为阳，心、脾为阴，肝、肾为至阴。《黄帝内经》则称脾为至阴。
三阳病也有里证，三阴病也有表证。病在表者，无论阴阳，多在足部经脉显现症状；病在里者，手经和足经都有涉及。阳明承气汤，攻下的是大肠而非胃，难道燥屎会停留在胃中吗？太阳抵当汤，攻下的是小肠而非膀胱；如果膀胱真有蓄血，应当像血淋一样小便不利，怎么能小便通利反而大便发黑呢？况且该证还兼见神志昏乱、胡言乱语如狂的症状，这是心的病变；因为心与小肠的脉络相通，所以气机也相通。
陶节庵说：伤寒出现沉脉，可以区分阴阳。意思是邪气在三阳经时，脉象都是浮的。等到脉变沉，就涉及三阳的里证和三阴经了。然而，如果脉浮而无力无神，那是阴虚到了极点，比邪气陷入里部导致里实证更加危险。张景岳着重论述了这一观点，功劳很大，绝不能说阴脉都是沉的，而浮脉就一定没有阴证。
三阴病都有呕吐腹泻、四肢逆冷的症状。这是因为邪气侵入三阴，并不是立刻进入脏，而是先扰动腑。寒邪在腑，所以变化出各种症状，如果动及脏，就会死亡。《灵枢》说：“邪气中于阴，则流注于腑”，就是这个道理。而且呕吐属于胃，腹泻属于大肠，四肢属于脾，所以邪气侵入三阴，最重视脾胃的功能。只要脾胃功能不败，邪气虽然入里，也容易治疗。
胆是清净之腑，没有直接出入的口窍，所以禁止使用汗、吐、下三法。然而所谓足少阳证的禁忌，是针对其经脉而言的，经脉之气难道没有出入吗？如果邪气入里，就不一定在胆，而在三焦了。三焦主管气化，虽然不像抵当汤、承气汤那样有形的实邪可攻，但调理气机升降的方法，对胆来说还比较远，对三焦却最切近，所以大柴胡汤中也加入攻下药，是为了三焦而设的。因此丹溪在《脉因证治》中说少阳禁三法，但也适宜用三法。
三阴病的下利，应与阳明病的燥实证对照看待。三阴病的大便寒实，称为阴结；三阳病的下利，称为协热利。那么难道没有寒性下利吗？回答说：寒性下利就是三阴病。
外感淫邪有六种，但张仲景以“伤寒”命名这部论著。方中行、张隐庵一定要把三阴三阳归属于六气，这是极大的错误。应该说，讲明白了这本书的道理，就能通用于治疗六气病了！然而从古至今，未见有这样的通人。
伤寒邪气在表，就分六经；邪气入里，也就分三焦。吴鞠通说温病分三焦，伤寒难道唯独不分三焦吗？这是对的。但他没有说明在表在里的区别，表述不够清晰。
少阴这一经，涵盖左右两肾，是水火同居的地方。寒邪与水气相合，火气被抑制，所以脉象沉细，只想睡觉，这是阳气被抑制而不能伸展；火气被抑制却又常常想要伸展，所以常有心烦想吐的现象。有人问：少阴入里，就与心相通，那个心烦，不就是心的病变吗？不知道寒邪如果真的进入心脏，必然会导致昏迷不醒，怎么能还有心烦呢？那个心烦，是因为下元的真火被寒邪抑制，不能抒发，只能一线阳气直上，扰乱包络的气机。
心不受邪，只有少阴一经不直接受邪，由手厥阴心包络代替。心包络是心的外围宫城。妇人热入血室的证候，就是男子热入心包的证候，验证多次了。张仲景对于热入血室，用小柴胡汤治疗。叶天士对于这个证候，特别忌讳柴胡，并非没有见解。徐灵胎讥笑他，未免鲁莽。仔细思考这个证候，与小柴胡汤有什么关系？张仲景的这个方子，大概是治疗少阳的热邪感应到心包络的。如果是热入心包，身体安静不想动，神志昏迷胡言乱语，邪气实的，也可能躁扰如狂，这都是热证。为什么没有寒入心包络的证候呢？盖用心包络虽然代替心君受邪，终究是纯火的脏器，与神明之主只隔一层，如果寒水贼邪上犯，必然是火衰神去，邪气窜入心脏致人死亡，是顷刻间的事。所以中寒伤心之证，死得极快，来不及施救。伤寒的邪气，不如中寒猛烈，不能立刻进入心包，必须等待化热之后熏蒸浸渍，同气相召。所以有热入血室，没有寒入血室；有热入心包，没有寒入心包。不是没有，有的话就会死。比如呕吐腹泻、恶寒、身体蜷缩、四肢厥逆、烦躁，就是心阳逐渐熄灭的表现，何况是猝然中寒的呢！
大便闭结，也有潮热、胡言乱语、神志昏迷不认识人的症状，完全与热邪侵犯心包无异，因为都是热在血分。应当通过脉象辨别：心包热者，左寸脉必然缓而滑；大便闭结者，右尺脉必然长而实。另外，少阴病，咳嗽且腹泻，胡言乱语的，是因为用火法强行发汗所致，小便必然困难；还有伤寒脉浮，用火法强行发汗，导致惊狂，坐卧不安的，用救逆汤主治。这两种情况，都是强行发汗导致亡阳的证候。汗是心液，心液虚，不能养神所致。大抵胡言乱语，总属于心神迷乱所致，但有邪气正在包络的，有邪气感动包络的，邪气的虚实不同，病的轻重有别。就像肝乘脾，腹部胀满，胡言乱语，寸口脉沉而紧，名叫纵，刺期门穴，也是因为邪气与心有感应。
伤寒传经，有本经的邪气延及彼经的，有前经的邪气移及后边的经的。合病、并病，都是邪气实盛到达该经。更有邪气在此经，却兼见彼经症状的；邪气在阳经，却兼见阴经症状的。邪气还没进入，症状怎么会显现？盖人身经络相通，一气相互感应，虽然有界限，终究难以截然分开。比如少阳病，脉浮大，上至关上，只想睡觉，闭眼就出汗，这是少阴心的病变，是心气不能承受少阳的疏泄所致。这是气机的感应，不是邪气由少阳已经进入了心。其他经这类情况很多。气机相感，大抵寒从寒、热从热，寒多感应于肺、肾，热多感应于心、肝，这就是所谓的同气相求。这与传经证候的虚实轻重之间，自然有辨别。有先感应而后邪气才传入的，有先感应而邪气最终也不传入的。前人对于传经的说法，喋喋不休，都没有阐明这一点，难道是认为浅显不足道吗？王勋臣极力诋毁分经的错误，这又是只知道气的相互感应，而不知道有形的邪气，本来各有界限。
《伤寒论》、《金匮要略》中，经常为死证设立方剂，这个意义最值得深思。
伤寒有病证不同而治疗方法相同的，比如自利不渴属于太阴，自利而渴属于少阴，都用四逆汤温补；有病证相同而治疗方法不同的，比如阳明病自利，腹痛的，这是内实，宜用下法；太阴病，如果用下法，就会导致胸下痞结硬满。究竟相同的必有其相同的原因，少阴口渴用四逆汤，是因为小便颜色白，下焦虚寒；太阴不渴，也是因为脏寒。不同的必有其不同的原因，腹痛宜下不宜下，一个能食，一个不能食。读书必须从这些地方，用心参详校对，自然会有领悟，然而必须先逐条熟读，才可以这样；否则抛弃本义，彼此错综，只会扰乱人心。
曾经读《素问·至真要大论》所说的“胜至，报气屈伏而未发也”。因而想到凡是治疗胜气，必须顾忌复气，不可太过，反而助长伏气为患。不然，复气发作后胜气又来，哪有止期呢？伤寒诸方，有寒热合用、咸辛酸苦并投的，虽然说是对证施治，也未尝不是顾虑复气的微意。六经复气，少阳、厥阴二经最甚。《内经》说是火燥热。又说木发无时，水随火。发汗则伤阳，阴盛者寒起；攻下则伤阴，阳盛者热生。而且有时发汗而阳更炽，攻下而阴更深，因为汗药多热，下药多寒。大法：如火胜，治以咸味，必须佐以甘酸，咸味是正治，甘味是子气，引导其去路，所谓泻之；酸味是母法，保护其根基，防止本气受制太过；火的复气是水，甘味制水，而酸味又泄水，所以火淫所胜，用酸味来复之。王冰注解说：不复其气，则淫气空虚，招致损伤。此旨精微，读《伤寒论》的人，必须透彻这一点。
治病必求其本。所谓本，有万病的公本，有各病的专本。治病者应当求各病的专本，而对治之，才称得上精切。薛立斋一类人，专门讲真水、真火，只是治疗公本罢了！《伤寒论》、《金匮要略》才是真正能见病治病，所以药味的增减，确切不移。读者往往于一方药味，须一一从本证来源去路、本经虚实、子母本气、标本胜复上，委曲搜求，确有见地，如同自己想出，他日自然能独出手眼，无需扶墙摸壁，岂不快事！
凡是读成方，必须先揣摩方前所列的症状，再看方中药味的主治对应，如果有不合心意的，尽可以拟改旁注，以等待日后考正。《伤寒论》、《金匮要略》中，有许多今人不能遵用的方子，向来注解者，都循例解说，甚至穿凿附会，求深反浅；只有舒驰远能不讳言所疑，但不自任不知，而必诋毁古人传误，未免讪上。实则胡言乱语，虚则郑声。然而胡言乱语也有虚实。实者，阳明腑实证，协热下利证，热入血室证，太阳蓄血证；虚者，如过汗亡阳，过下亡阴，《内经·评热论》所谓汗出不退，狂言失志的，都是。乃五脏的津液干枯，脏体燥热，神无所养。经曰：津液相成，神乃自生。津虚，所以神昏乱。郑声，是邪声。旧解谓郑重也，尾声重浊。这是实，不是虚。凡气虚者，发语之初，声音如常，及其中、末，气有不续，声音忽然转变像他人，话语不像其人平日之本声，所以说邪也。
六经篇首，都列中风脉证一条，是借以衬托明白伤寒的脉证。大概中风间或有不挟寒的，而伤寒则必因于风，风力挟寒伤人，极重者为中寒，次为伤寒，轻即中风。可见六经有中风表证，即皆有伤寒表证。陶节庵直中之说，难道是杜撰的吗？况且《内经》更有中阳溜经，中阴溜腑的明文耶！但风寒初伤在经络，虽属于阴，在病气仍属于表，其治法总不外温散。太阳篇中六经初伤的证候具备，可按而考证。
伤寒一病，初起多同于中风，死证多类于中寒。
《伤寒论》一部书，只有寒死证，无热死证。白虎汤、承气汤，本来不是死证。如果是温病，则相反了。
“反”字有几个解释：不应也，却也，复也。如弱反在关，濡反在巅，只是语助词，俗言“却也”。当不能食，而反能食，是不应也。如得之，反发热，脉沉的，麻黄细辛附子汤，谓既始得之，又有发热表证，虽脉沉，也宜用汗法。读者应当随文生义，不要执一而例百。
《伤寒论》全论外感，《金匮要略》也有外证。不见一方用羌活的，为什么呢？即使是风湿，也只只用麻黄、薏苡仁、附子、白术、黄芪、防己。
诸家都说六经每篇有提纲，其后凡是浑言某经病的，就是某经提纲所列诸证。然而太阴病，脉浮的，可发汗，宜桂枝汤。如果果真是腹满而吐，食不下，自利益甚，时腹自痛，纯属阴寒内证，仅据脉浮就用汗法可以吗？这种地方更须参详，读书固不可执一而例百。
寒极反热，热极反寒，这是化气，真假勿混淆，前人辨析过了。至于所以反热、反寒的缘故，始终没有阐明。如果说寒邪在内，而逼人身之热气于外，似乎对寒极反热的意义，不太贴切。我私下想，寒极反热者，如果外见面赤、唇红，尚是真阳外越，仅可称之为假热；惟独外无热象，而燥渴索饮，漱水不咽，小便涩大便秘，时下微溏，这是阴寒内结，微阳欲熄，不能运化津液以滋润经络脏腑，所谓水冷成冰的寒燥，这才是真正的反热。热极反寒者，如果因腠理开泄，卫阳不固，尚是正气内怯，仅可称之为假寒；惟独热邪涌盛，奔逸于经络脏腑之中，内外津液全为灼干，气管全为枯涩，热邪奔迫不利，像人疾走而跌倒，壅积而不得四达，这才是真正的反寒。前人在这些治法上，多以回阳泄热，粗略立论。殊不知治假热者，引火归元；治反热者，温化津液。岂可固执？治假寒者，生津益气。治反寒者，生津泄气：岂可相同？假寒、假热，为虚气之游行，犹有此二气。反寒、反热，为虚象之疑似。其寒，正是热之极；其热，正是寒之极。
San Yin and San Yang (Three Yin and Three Yang meridians): From the perspective of exterior meridians, Yang meridians are Yang, and Yin meridians are Yin; from the perspective of interior Zang-Fu organs, Zang organs are Yin, and Fu organs are Yang.
At the exterior level, cold pathogen injuring Ying Qi (nutritive Qi circulating within the vessels) involves blood within the vessels, which is Yin; wind pathogen injuring Wei Qi (defensive Qi circulating outside the vessels) involves Qi outside the vessels, which is Yang. At the interior level, among the Fu organs, the Stomach is Yang, Large Intestine is Yin, Bladder is Yang, Small Intestine is Yin, and Gallbladder is more Yin; among the Zang organs, Lung is Yang, Heart and Spleen are Yin, Liver and Kidney are "Zhi Yin" (Extreme Yin). *Huangdi Neijing* (Yellow Emperor's Inner Canon) refers to Spleen as Zhi Yin.
San Yang diseases also have interior syndromes, and San Yin diseases also have exterior syndromes. Syndromes at the exterior, regardless of Yin or Yang, mostly manifest in the Foot meridians; syndromes at the interior involve both Hand and Foot meridians. Chengqi Tang (Cathartic Decoction) for Yangming syndrome attacks the Large Intestine, not the Stomach; how could dry feces remain in the Stomach? Didang Tang (Attacking Stasis Decoction) for Taiyang syndrome attacks the Small Intestine, not the Bladder; if there were truly blood stasis in the Bladder, it would resemble hematuria with difficult urination, so how could urination be free while stool is black? Moreover, this syndrome includes symptoms like confusion and delirious mania, which are Heart syndromes; because the Heart and Small Intestine meridians are connected, their Qi mechanisms are also interconnected.
Tao Jian'an stated: In Shanghan (Cold Damage), the appearance of a Chen Mai (Deep Pulse) can distinguish Yin and Yang. He meant that when pathogens are in the San Yang meridians, the pulse is always Fu (Floating). When the pulse becomes Chen (Deep), it involves the interior of San Yang and the San Yin meridians. However, a Fu pulse that is weak and lacks spirit indicates extreme Yin deficiency, which is even more dangerous than pathogens sinking into the interior causing excess syndromes. Zhang Jingyue emphasized this point significantly, correctly asserting that one cannot say all Yin pulses are Deep, nor that Floating pulses exclude Yin conditions.
San Yin diseases all present with vomiting, diarrhea, and cold limbs. This is because when pathogens enter San Yin, they do not immediately invade the Zang organs but first disturb the Fu organs. Cold pathogens in the Fu organs cause various symptom changes; if they affect the Zang organs, death ensues. *Ling Shu* (Spiritual Pivot) states: "Pathogens striking Yin flow into the Fu organs," which is correct. Furthermore, vomiting relates to the Stomach, diarrhea to the Large Intestine, and limbs to the Spleen; thus, when pathogens enter San Yin, the Spleen and Stomach are most critical. If Spleen and Stomach function remains intact, even if pathogens enter the interior, treatment is easier.
The Gallbladder is a "Clear" Fu organ with no direct openings for entry or exit, so the three methods (sweating, emesis, purging) are contraindicated. However, the prohibition regarding Shaoyang (Lesser Yang) applies to its meridian; does meridian Qi lack movement? If pathogens move inward, they may not stay in the Gallbladder but move to the San Jiao (Triple Burner). San Jiao governs Qi transformation; although it lacks tangible excess like in Didang Tang or Chengqi Tang, methods regulating Qi ascent and descent are more relevant to San Jiao than Gallbladder. Therefore, Da Chaihu Tang (Major Bupleurum Decoction) includes purgatives specifically for San Jiao. Thus, Danxi in *Mai Yin Zheng Zhi* (Pulse, Etiology, Syndrome, and Treatment) noted that while Shaoyang prohibits the three methods, they are sometimes appropriate.
Diarrhea in San Yin should be contrasted with dryness-excess in Yangming. Cold-solid stool in San Yin is called "Yin Jie" (Yin Knot); diarrhea in San Yang is called "Xie Re Li" (Collateral Heat Diarrhea). Is there cold diarrhea? Yes, cold diarrhea is synonymous with San Yin disease.
There are six external pathogenic factors, yet Zhang Zhongjing titled his treatise *Shanghan Lun* (Treatise on Cold Damage). Fang Zhongxing and Zhang Yinan erroneously linked San Yin and San Yang strictly to the Six Qi (Six Climatic Factors). One should understand that mastering the principles of this book allows application to treating Six Qi disorders, though such comprehensive mastery is rare.
When Shanghan pathogens are at the exterior, they are differentiated by Six Meridians; upon entering the interior, they are differentiated by San Jiao. Wu Jutong stated that Warm Diseases are differentiated by San Jiao; why should Shanghan not also use San Jiao differentiation? This is correct, but failing to specify exterior vs. interior makes the explanation unclear.
Shaoyin (Lesser Yin) encompasses both kidneys, where Water and Fire reside together. Cold pathogens combine with Water Qi, suppressing Fire, resulting in a Chen Xi (Deep and Fine) pulse and somnolence, indicating suppressed Yang unable to extend. Suppressed Fire attempts to extend, causing irritability and nausea. Some ask: Since Shaoyin connects to the Heart, isn't irritability a Heart syndrome? If cold truly entered the Heart, coma would occur, not mere irritability. This irritability arises because Yuan Fire (True Fire) in the lower origin is suppressed by cold, unable to discharge, forcing a thread of Yang Qi upward to disturb Pericardium Qi.
The Heart does not accept pathogens directly; Shaoyin is spared, replaced by Shoujueyin Pericardium Meridian. The Pericardium is the outer palace of the Heart. Women's "Heat Entering Blood Chamber" is equivalent to men's "Heat Entering Pericardium." Zhang Zhongjing treated Heat Entering Blood Chamber with Xiao Chaihu Tang (Minor Bupleurum Decoction). Ye Tianshi contraindicated Chaihu for this condition, which was insightful. Xu Lingtai mocked him rashly. Careful analysis shows Xiao Chaihu Tang treats Shaoyang heat affecting the Pericardium. True Heat Entering Pericardium presents with stillness, coma, and delirium; excess heat may cause mania. Why no Cold Entering Pericardium? Although Pericardium substitutes for the Heart, it is a pure Fire organ closely linked to Spirit. If Cold/Water invades, it causes Fire decline and Spirit departure, leading to rapid death. Thus, Cold Damage rarely reaches Pericardium unless it transforms into Heat, attracting similar Qi. Hence, Heat enters Blood Chamber/Pericardium, but Cold does not (if it did, death would follow). Symptoms like vomiting, diarrhea, aversion to cold, curling up, cold limbs, and restlessness indicate fading Heart Yang.
Constipation with tidal fever, delirium, and confusion mirrors Heat invading Pericardium because both involve Heat in the Blood aspect. Differentiate by pulse: Pericardium Heat shows a Huan Hua (Slow and Slippery) Left Cun pulse; constipation shows a Chang Shi (Long and Excess) Right Chi pulse. Additionally, Shaoyin cough with diarrhea and delirium results from forced sweating via fire therapy, causing difficult urination. Shanghan with Fu pulse treated with fire therapy causing panic and restlessness requires Niujtang (Rescue Decoction). Both are cases of Yang collapse from forced sweating. Sweat is Heart fluid; deficiency fails to nourish Spirit. Delirium stems from Spirit confusion due to Pathogen affecting or disturbing Pericardium. For example, Liver overacting on Spleen causes abdominal fullness and delirium with Chen Jin (Deep and Tight) Cun Kou pulse, named "Zong"; puncturing Qimen acupoint works because Pathogen interacts with Heart.
Shanghan transmission involves pathogens extending from one meridian to another or shifting forward/backward. He Bing (Combined Disease) and Bing Bing (Concurrent Disease) involve excess pathogens reaching specific meridians. Sometimes pathogens in one meridian show symptoms of another; Yang meridian pathogens show Yin symptoms. How can symptoms appear without pathogen entry? Meridians connect, and Qi resonates; boundaries exist but are permeable. For instance, Shaoyang pulse Fu Da rising to Guan, somnolence, and sweating upon closing eyes reflect Shaoyin Heart syndrome, where Heart Qi cannot withstand Shaoyang dispersal. This is Qi resonance, not pathogen migration. Generally, Cold resonates with Cold (Lung/Kidney), Heat with Heat (Heart/Liver). This differs from transmission patterns. Some resonate before pathogen arrival; some resonate but pathogen doesn't arrive. Predecessors debated transmission endlessly without explaining this. Wang Xunchen criticized meridian differentiation, ignoring that tangible pathogens have boundaries.
*Shanghan Lun* and *Jingui Yaolue* prescribe formulas for fatal syndromes, a profound concept.
Shanghan has different syndromes with same treatments (e.g., non-thirsty diarrhea in Taiyin vs. thirsty diarrhea in Shaoyin, both treated with Sini Tang [Frigid Extremities Decoction]); and same syndromes with different treatments (e.g., Yangming diarrhea with abdominal pain requires purging; Taiyin diarrhea requires caution against purging to avoid chest stiffness). Similarities have reasons (Shaoyin thirst uses Sini Tang due to clear urine/lower jiao cold; Taiyin no-thirst due to organ cold); differences have reasons (appetite status). Readers must study these nuances after memorizing texts to avoid confusion.
Studying *Zhi Yao Da Lun*, "Victorious Qi arrives, Repaying Qi lies dormant." Treating Victorious Qi must consider Repaying Qi to avoid exacerbating latent Qi. Otherwise, cycles continue. Shanghan formulas combining cold/hot or salty/sour/bitter/pungent herbs reflect consideration of Repaying Qi. Repaying Qi is strongest in Shaoyang and Jueyin (*Neijing*: Fire/Dryness/Heat). Sweating injures Yang (Cold rises if Yin excess); purging injures Yin (Heat rises if Yang excess). Sweating may increase Yang heat; purging may deepen Yin cold due to herb properties. General rule: For Fire excess, use Salty taste (corrective), aided by Sweet (child Qi, guides outflow) and Sour (mother Qi, protects root). Fire's repaying Qi is Water; Sweet controls Water, Sour drains Water. So, for Fire excess, use Sour to repay. Wang Bing notes: Not repaying Qi leaves excess Qi empty, inviting damage. This subtlety must be understood by *Shanghan* readers.
Treating disease seeks the Root. There is a common Root for all diseases and specific Roots for each. Treaters should target specific Roots for precision. Xue Lizhai focused on True Water/Fire (Common Root), whereas *Shanghan* and *Jingui* treat specific roots precisely. Readers should analyze formula ingredients based on syndrome origin, meridian excess/deficiency, parent-child relationships, and root/branch dynamics to develop independent insight.
When studying established formulas, compare listed symptoms with ingredient actions. Modify or annotate if discrepancies arise. *Shanghan* and *Jingui* contain formulas hard to apply today; commentators often force interpretations. Shu Chiyuan questioned doubts but unfairly blamed ancient errors. Real delirium is excess; Zheng Sheng (repetitive speech) is deficiency. However, delirium has excess types (Yangming fu-excess, collateral heat diarrhea, heat entering blood chamber, Taiyang blood stasis) and deficiency types (excessive sweating/Yang collapse, excessive purging/Yin collapse, fluid exhaustion causing Spirit loss). Zheng Sheng is actually "Evil Sound" (weak Qi causing voice changes late in speech), not true deficiency.
Six Meridians chapters list Wind Strike pulse/syndromes to contrast Shanghan. Wind Strike may not involve Cold, but Shanghan always involves Wind carrying Cold. Severe is Zhong Han (Direct Cold), moderate is Shang Han, mild is Feng Zhong (Wind Strike). Thus, Six Meridians Wind Strike exterior syndromes imply Shanghan exterior syndromes. Tao Jian'an's "Direct Invasion" theory is valid, supported by *Neijing*. Initial Wind-Cold in meridians is exterior in nature, treated with warming dispersion. Sunyang chapter details initial injuries.
Shanghan begins similarly to Wind Strike; fatal cases resemble Direct Cold.
*Shanghan Lun* describes only Cold fatal syndromes, not Heat. Baihu Tang and Chengqi Tang are not inherently fatal. In Warm Diseases, it is reversed.
"Fan" (Reverse/Opposite) has multiple meanings: "Unexpectedly," "Yet," or "Again." E.g., "Weak pulse unexpectedly at Guan" means "just." "Unable to eat, yet able to eat" means unexpected. "Initial onset, yet fever with deep pulse" implies using Mahuang Xixin Fuzi Tang despite deep pulse because exterior signs persist. Readers must interpret contextually, not rigidly.
*Shanghan* discusses external infections; *Jingui* also covers external signs. No Qiang Huo (Notopterygium) is used. Even for Wind-Damp, only Mahuang, Yiyi Ren, Fuzi, Baizhu, Huangqi, and Fangji are used.
Commentators claim each meridian chapter has a guideline. Later mentions of "Meridian Disease" refer to these guidelines. However, Taiyin disease with Fu pulse suggests sweating with Guizhi Tang. If symptoms are purely internal cold (abdominal fullness, vomiting, diarrhea, pain), is Fu pulse alone sufficient for sweating? Such cases require careful analysis; reading must not be rigid.
Extreme Cold reverses to Heat; Extreme Heat reverses to Cold (Qi transformation). Predecessors distinguished true/false but didn't explain the mechanism. Saying "internal Cold forces external Heat" is insufficient. True reverse heat: No external heat signs, but dry mouth wanting water, rinsing without swallowing, scant urine, constipation with occasional loose stools. This is internal Cold binding, faint Yang failing to transform fluids ("cold water turning to ice"). True reverse cold: No external cold signs, but surging Heat drying fluids, obstructing Qi flow like a runner tripping. Predecessors vaguely suggested restoring Yang or clearing Heat. Actually, treat false heat by guiding Fire back to source; treat true reverse heat by warming and transforming fluids. Treat false cold by generating fluids/Qi; treat true reverse cold by generating fluids and venting Qi. False cold/heat are wandering deficient Qi; true reverse cold/heat are illusory extremes mirroring the opposite extreme.