六变者，表里寒热虚实也。是即医中之关键。明此六者，万病皆指诸掌矣。以表里言之
，则风、寒、暑、湿、火、燥感于外者是也。以里言之，则七情、劳欲、饮食伤于内者是也
。寒者，阴之类也。或为内寒，或为外寒，寒者多虚。热者，阳之类也。或为内热，或为外
热，热者多实。虚者，正气不足也，内出之病多不足。实者，邪气有余也，外入之病多有余
。六者之详，条列如下。
表证者，邪气之自外而入者也。凡风寒暑湿火燥，气有不正，皆是也。经曰∶清风大来
，燥之胜也。风木受邪，肝病生焉。热气大来，火之胜也。金燥受邪，肺病生焉。寒气大来
，水之胜也。火热受邪，心病生焉。湿气大来，土之胜也。寒水受邪，肾病生焉。风气大来
，木之胜也。土湿受邪，脾病生焉。又曰∶冬伤于寒，春必病温。春伤于风，夏生飧泄。夏
伤于暑，秋必咳疟。秋伤于湿，冬生咳嗽。又曰∶风从其冲后来者为虚风，伤人者也，主杀
主害者。凡此之类，皆言外来之邪。但邪有阴阳之辨，而所伤亦自不同。盖邪虽有六，化止
阴阳。阳邪化热，热则伤气；阴邪化寒，寒则伤形。伤气者，气通于鼻，鼻通于脏。故凡外
受暑热而病有发于中者，以热邪伤气也。伤形者，浅则皮毛，深则经络，故凡外受风寒而病
为身热体痛者，以寒邪伤形也。经曰∶寒则腠理闭，气不行，故气收矣。炅则腠理开，营卫
通，汗大泄，故气泄矣。此六气阴阳之辨也。然而六邪之感于外者，又惟风寒为最。盖风为
百病之长，寒为杀厉之气。人身内有脏腑，外有经络，凡邪气之客于形也，必先舍于皮毛；
留而不去，乃入于孙络；留而不去，乃入于络脉；留而不去，乃入于经脉，然后内连五脏，
散于肠胃，阴阳俱感，五脏乃伤，此邪气自外而内之次也。然邪气在表，必有表证，既见表
证，则不可攻里。若误攻之，非惟无涉，且恐里虚则邪气乘虚愈陷也。表证既明，则里证可
因而解矣。故表证之辨，不可不为之先察。
一、人身脏腑在内，经络在外，故脏腑为里，经络为表。在表者，手足各有六经，是为
十二经脉。以十二经脉分阴阳，则六阳属腑为表，六阴属脏为里。以十二经脉分手足，则足
经之脉长而且远，自上及下，遍络四体，故可按之以察周身之病。手经之脉短而且近，皆出
入于足经之间，故凡诊伤寒外感者，则但言足经不言手经也。然而足之六经，又以三阳为表
，三阴为里。而三阳之经，则又以太阳为阳中之表，以其脉行于背，背为阳也。阳明为阳中
之里，以其脉行于腹，腹为阴也。少阳为半表半里，以其脉行于侧，三阳传遍而渐入三阴也
。故凡欲察表证者，但当分前后左右，而以足三阳经为主。然三阳之中，则又惟太阳一经，
包覆肩背，外为周身之之纲维，内连五脏六腑之肓 ？此诸阳之主气，犹四通八达之衢也。
故凡风寒之伤人，必多自太阳经始。
一、足三阴之经皆自脚上腹，虽亦在肌表之间，然三阴主里，而凡风寒自表而入者，未
有不由阳经而入阴分也。若不由阳经迳入三阴者，即为直中阴经，必连脏矣。故阴经无可据
之表证。
一、寒邪在表者，必身热无汗，以邪闭皮毛也。
一、寒邪客于经络，必身体疼痛，或拘急而酸者，以邪气乱营气，血脉不利也。
一、寒邪在表而头痛者，有四经焉。足太阳脉挟于头顶，足阳明脉上至头维，足少阳脉
上行两角，足厥阴脉上会于巅，皆能为头痛也。故惟太阴、少阴皆无头痛之证。
一、寒邪在表多恶寒者，盖伤于此者必恶此，所谓伤食恶食，伤寒恶寒也。
一、邪气在表，脉必紧数者，营气为邪所乱也。
一、太阳经脉起目内 ，上顶巅，下项，挟脊行腰 ，故邪在太阳者，必恶寒发热而
兼头项痛，腰脊强，或膝 酸疼也。
一、阳明经脉起自目下，循面鼻，行胸腹。故邪在阳明者，必发热微恶寒，而兼目痛鼻
干不眠也。
一、少阳为半表半里之经，其脉绕耳前后，由肩井下胁肋。故邪在少阳者，必发热而兼
耳聋胁痛，口苦而呕，或往来寒热也。
以上皆三阳之表证，但见表证，则不可攻里。或发表，或微解，或温散，或凉散，或温
中托里而为不散之散，或补阴助阴而为云蒸雨化之散。呜呼！意有在而言难尽也。惟慧者之心悟之。
一、表证之脉。仲景曰∶寸口脉浮而紧，浮则为风，紧则为寒，风则伤卫，寒则伤营，
营卫俱病，骨节烦疼，当发其汗也。《脉经》注曰∶风为阳，寒为阴，卫为阳，营为阴，风
则伤阳，寒则伤阴，各从其类而伤也。故卫得风则热，营得寒则痛，营卫俱病，故致骨节烦
疼，当发汗解表而愈。
一、浮脉本为属表，此固然也。然有邪寒初感之甚者，拘束卫气，脉不能达，则必沉而
兼紧，此但当以发热身痛等表证参合而察之，自可辨也。又若血虚动血者，脉必浮大。阴虚
水亏者，脉必浮大。内火炽盛者，脉必浮大。关阴格阳者，脉必浮大。若此者，俱不可一概
以浮为表论，必当以形气病气有无外证参酌之。若本非表证，而误认为表，则杀人于反掌之间矣。
一、外感寒邪，脉大者，必病进，以邪气日盛也。然必大而兼紧，方为病进。若先小而
后大，及渐大渐缓者，此以阴转阳，为胃气渐至，将解之兆也。
一、寒邪未解，脉息紧而无力者，无愈期也。何也？盖紧者，邪气也。力者，元气也，
紧而无力，则邪气有余而元气不足也。元气不足，何以逐邪？临此证者，必能使元阳渐充，
则脉渐有力，自小而大，自虚而实，渐至洪滑，则阳气渐达，表将解矣。若日见无力，而紧
数日进，则危亡之兆也。
一、病必自表而入者，方得谓之表证，若由内以及外，便非表证矣。经曰∶从内之外者
调其内，从外之内者治其外。从内之外而盛于外者，先治其内而后治其外；从外之内而盛于
内者，先治其外而后调其内。此内外先后之不可不知也。
一、伤风、中风，虽皆有风之名，不可均作表证。盖伤风之病，风自外入者也。可散之
、温之而已，此表证也。中风之病，虽形证似风，实由内伤所致。本无外邪，故不可以表证论治。法具本条。
一、发热之类，本为火证，但当分辨表里。凡邪气在表发热者，表热而里无热也，此因
寒邪，治宜解散。邪气在里发热者，必里热先甚而后及于表也，此是火证，治宜清凉。凡此
内外，皆可以邪热论也。若阴虚水亏而为骨蒸夜热者，此虚热也。又不可以邪热为例，惟壮
水滋阴可以治之。
一、湿燥二气，虽亦外邪之类，但湿有阴阳，燥亦有阴阳。湿从阴者为寒湿，湿从阳者
为湿热。燥从阳者因于火，燥从阴者发于寒。热则伤阴，必连于脏。寒则伤阳，必连于经。
此所以湿燥皆有表里，必须辨明而治之。
一、湿证之辨，当辨表里。经曰∶因于湿，首如裹。又曰∶伤于湿者，下先受之。若道
路冲风冒雨，或动作辛苦之人，汗湿沾衣，此皆湿从外入者也。若嗜好酒浆生冷，以致泄泻
、黄胆、肿胀之类，此湿从内出者也。在上在外者，宜微从汗解；在下在里者，宜分利之。
湿热者宜清宜利；寒湿者宜补脾温肾。
一、燥证之辨，亦有表里。经曰∶清气大来，燥之胜也，风木受邪，肝病生焉。此中风
之属也。盖燥胜则阴虚，阴虚则血少，所以或为牵引，或为拘急，或为皮腠风消，或为脏腑
干结，此燥从阳化，营气不足，而伤乎内者也。治当以养营补阴为主。若秋令太过，金气胜
而风从之，则肺先受病，此伤风之属也。盖风寒外束，气应皮毛，故或为身热无汗，或为咳
嗽喘满，或鼻塞声哑，或咽喉干燥，此燥以阴生，卫气受邪，而伤乎表者也。治当以轻扬温
散之剂，暖肺去寒为主。
六变，指的是表、里、寒、热、虚、实这六种基本病机。这是医学中的关键所在。明白了这六个方面，各种疾病就都能像看手掌上的纹路一样清晰明了了。从表里来说，风、寒、暑、湿、火、燥这些外邪侵袭人体外部，属于表证；从里来说，七情（喜、怒、忧、思、悲、恐、惊）、劳累过度、房事不节、饮食不当等损伤人体内部，属于里证。寒，属于阴的范畴。或者是内寒，或者是外寒，寒证大多属于虚证。热，属于阳的范畴。或者是内热，或者是外热，热证大多属于实证。虚，是指正气不足，由内而生的疾病多表现为不足。实，是指邪气有余，由外侵入的疾病多表现为有余。关于这六者的详细内容，分条列举如下。
表证，是指邪气从外部侵入人体所导致的病证。凡是风、寒、暑、湿、火、燥这些不正之气，都属于此类。《内经》说：清风大来，是燥气偏胜的表现。风气受邪，肝病由此产生。热气大来，是火气偏胜的表现。金燥受邪，肺病由此产生。寒气大来，是水气偏胜的表现。火热受邪，心病由此产生。湿气大来，是土气偏胜的表现。寒水受邪，肾病由此产生。风气大来，是木气偏胜的表现。土湿受邪，脾病由此产生。又说：冬天感受寒邪，春天必定发生温病；春天感受风邪，夏天必然发生完谷不化的泄泻；夏天感受暑邪，秋天必定发生咳嗽疟疾；秋天感受湿邪，冬天必然发生咳嗽。又说：从冲后方向吹来的风称为虚风，这种风伤害人，主杀伐和危害。以上这些，都在说明外来邪气。但邪气有阴阳的区别，所伤害的部位自然也不同。大概邪气虽然有六种，但其变化归结为阴阳两类。阳邪转化为热，热则伤害气；阴邪转化为寒，寒则伤害形体。伤害气的，气通于鼻，鼻通于内脏。所以凡是外受暑热而发病在体内的，是因为热邪伤了气。伤害形体的，浅则在皮毛，深则在经络，所以凡是外受风寒而发病表现为身体发热、肢体疼痛的，是因为寒邪伤了形体。《内经》说：寒则腠理闭塞，气机运行不畅，所以气机收敛。热则腠理开泄，营卫通畅，大汗淋漓，所以气随汗泄。这就是六气阴阳的区别。然而六邪中侵袭体表的，又以风邪和寒邪最为常见。因为风是百病的先导，寒是致死的厉气。人体内有脏腑，外有经络，凡是邪气客居形体，必定先停留在皮毛；停留不去，就进入孙络；停留不去，就进入络脉；停留不去，就进入经脉，然后内连五脏，散布于肠胃，阴阳都受到感应，五脏才会受伤，这是邪气由外向内传变的次序。既然邪气在表，必定出现表证，既已见到表证，就不可以攻治里证。如果错误地攻里，不仅无益，而且恐怕导致里气虚弱，邪气乘虚进一步陷入体内。表证既然明确，里证就可以随之解决了。所以对表证的辨别，不可以不预先考察。
第一，人体的脏腑在内，经络在外，所以脏腑属里，经络属表。在表者，手足各有六条经脉，合为十二经脉。用十二经脉来分阴阳，则六条阳经属于腑，属表；六条阴经属于脏，属里。用十二经脉来分手足，则足经的脉道长而且远，从上到下，遍布四肢，所以可以通过诊察足经来了解全身的疾病。手经的脉道短而且近，都出入于足经之间，所以凡是诊察伤寒外感病时，只谈足经而不谈手经。然而足部的六条经脉，又以三阳经为表，三阴经为里。而在三阳经中，又以太阳经为阳中之表，因为其经脉行于背部，背属阳。阳明经为阳中之里，因为其经脉行于腹部，腹属阴。少阳经为半表半里，因为其经脉行于侧面，三阳经传遍之后逐渐传入三阴经。所以凡是想要察知表证的，应当区分前、后、左、右，而以足部三条阳经为主。但在三阳经之中，又唯独太阳一经，包覆肩背，对外是全身的纲维，对内连接五脏六腑的肓膜。这是诸阳经的主要气机，就像四通八达的交通枢纽一样。所以凡是风寒伤人，大多从太阳经开始。
第二，足部三条阴经的经脉都是从脚上行至腹部，虽然也在肌肤体表之间，但三阴经主里，而且凡是风寒从表侵入的，没有不经过阳经而进入阴分的。如果不经过阳经直接侵入三阴经的，就称为直中阴经，必定牵连到脏腑。所以阴经没有可以作为依据的表证。
第三，寒邪在表，必定身体发热且无汗，这是因为邪气闭塞了皮毛。
第四，寒邪客居于经络，必定身体疼痛，或者拘急酸痛，这是因为邪气扰乱了营气，血脉运行不利。
第五，寒邪在表而导致头痛的，涉及四条经脉。足太阳经脉夹行于头顶，足阳明经脉上行至头维穴，足少阳经脉上行至两侧角，足厥阴经脉上会于巅顶，都能引起头痛。所以只有太阴经和少阴经没有头痛的症状。
第六，寒邪在表大多伴有恶寒，这是因为伤害于此的人必定厌恶此邪，所谓伤食则厌恶食物，伤寒则厌恶寒冷。
第八，太阳经脉起于目内眦，上行至头顶，下行至项部，夹脊柱行于腰部，所以邪气在太阳经的，必定恶寒发热并且兼有头项痛、腰脊强直，或者膝盖酸痛。
第九，阳明经脉起自眼下，沿面部鼻旁，行于胸腹部。所以邪气在阳明经的，必定发热微恶寒，并且兼有目痛、鼻干、失眠等症状。
第十，少阳经是半表半里的经脉，其经脉环绕耳前后，由肩井穴下行至胁肋。所以邪气在少阳经的，必定发热并且兼有耳聋、胁痛、口苦、呕吐，或者往来寒热等症状。
以上都是三阳经的表证，只要见到表证，就不可以攻治里证。或者使用发汗解表的方法，或者轻微疏解，或者温散，或者凉散，或者通过温补中焦托举里气来达到不散而散的效果，或者通过补阴助阴来达到云蒸雨化般的发散效果。唉！其中的意蕴在于心悟，言语难以穷尽。只有聪慧的人才能心领神会。
第十一，关于表证的脉象。张仲景说：寸口脉浮而紧，浮表示风邪，紧表示寒邪，风邪伤害卫气，寒邪伤害营气，营卫都生病，骨节烦疼，应当发汗治疗。《脉经》注释说：风为阳，寒为阴，卫为阳，营为阴，风邪伤害阳气，寒邪伤害阴气，各自按照同类相感的规律受到伤害。所以卫气受风则发热，营气受寒则疼痛，营卫都生病，所以导致骨节烦疼，应当发汗解表而痊愈。
第十二，浮脉本来属于表证，这是肯定的。但是如果有寒邪初感严重的，束缚卫气，脉气不能通达，则脉象必定沉而兼紧，这种情况应当结合发热、身痛等表证来综合考察，自然可以辨别。另外如果是血虚动血的情况，脉象必定浮大。阴虚水亏的情况，脉象必定浮大。内火炽盛的情况，脉象必定浮大。关格阴盛格阳的情况，脉象必定浮大。像这些情况，都不可以一概将浮脉当作表证论断，必须根据形体气质、病气以及是否有外证来斟酌判断。如果本来不是表证，却误认为是表证，那么杀人就在反掌之间了。
第十三，外感寒邪，脉象大的，必定病情进展，因为邪气日益强盛。但是必须脉大且兼紧，才算是病情进展。如果先小而后大，以及逐渐变大逐渐缓和的，这是阴转阳，是胃气逐渐恢复，即将解除的征兆。
第十四，寒邪未解，脉息紧而无力的，没有痊愈的日期。为什么呢？因为紧表示邪气，力表示元气，紧而无力，就是邪气有余而元气不足。元气不足，凭什么驱逐邪气？遇到这种证候，必须使元阳逐渐充盛，则脉象逐渐有力，自小而大，自虚而实，逐渐变为洪滑，则阳气逐渐通达，表证将要解除。如果日渐无力，而紧数之脉日益进展，则是危亡的征兆。
第十五，病必定是从表侵入的，才叫做表证，如果是由内及外，就不是表证了。《内经》说：从内之外者调其内，从外之内者治其外。从内之外而表现在外的症状严重的，先治其内而后治其外；从外之内而表现在内的症状严重的，先治其外而后调理其内。这是内外先后顺序不可不知道的道理。
第十六，伤风和中风，虽然都有“风”的名称，不可以都作为表证处理。伤风的病，风是从外部侵入的。可以用发散、温散的方法治疗，这才是表证。中风的病，虽然形态症状类似风邪致病，实际上是由内伤引起的。本来没有外邪，所以不可以按表证论治。治疗方法详见本条。
第十七，发热之类的症状，本来是火证，但应当分辨表里。凡是邪气在表而发热的，是表热而里没有热，这是因为寒邪所致，治疗宜解散。邪气在里而发热的，必定是里热先严重而后波及到表，这是火证，治疗宜清凉。凡是这些内外情况，都可以按邪热来论述。如果是阴虚水亏导致的骨蒸夜热，这是虚热。又不可以按邪热来处理，只有壮水滋阴才可以治疗它。
第十八，湿气和燥气，虽然也是外邪的一类，但湿有阴阳，燥也有阴阳。湿从阴者为寒湿，湿从阳者为湿热。燥从阳者因于火，燥从阴者发于寒。热则伤害阴，必定牵连到脏。寒则伤害阳，必定牵连到经。这就是为什么湿和燥都有表里之分，必须辨明而治疗的原因。
第十九，湿证的辨别，应当分辨表里。《内经》说：因于湿，头部感觉像被包裹一样沉重。又说：伤于湿的人，下部先受邪。如果在道路冲风冒雨，或者动作辛苦的人，汗湿沾衣，这些都是湿从外部侵入的。如果嗜好酒浆生冷，以致发生泄泻、黄疸、肿胀等病，这是湿从内部产生的。在上在外的，宜微微从汗解；在下在里的，宜分利小便。湿热者宜清宜利；寒湿者宜补脾温肾。
第二十，燥证的辨别，也有表里。《内经》说：清气大来，是燥气偏胜的表现，风木受邪，肝病由此产生。这属于中风的范畴。大概燥胜则阴虚，阴虚则血少，所以有的表现为牵引不适，有的表现为拘急，有的表现为皮肤腠理消瘦，有的表现为脏腑干结，这是燥从阳化，营气不足，而伤害在内部的情况。治疗应当以养营补阴为主。如果秋令太过，金气胜而风随之，则肺先受病，这属于伤风的范畴。大概风寒外束，气应于皮毛，所以有的表现为身体发热无汗，有的表现为咳嗽喘满，有的表现为鼻塞声哑，有的表现为咽喉干燥，这是燥以阴生，卫气受邪，而伤害在表部的情况。治疗应当以轻扬温散的药剂，暖肺去寒为主。
The Six Transformations refer to the six fundamental pathological mechanisms: Exterior (Biao), Interior (Li), Cold (Han), Heat (Re), Deficiency (Xu), and Excess (Shi). These are the key points in medicine. Understanding these six aspects allows one to comprehend all diseases as clearly as reading lines on one's palm. Regarding Exterior and Interior, wind, cold, summerheat, dampness, fire, and dryness invading from the exterior belong to Exterior patterns. Regarding Interior, emotional disturbances (Seven Emotions), overwork, sexual indiscretion, and dietary injuries damaging the interior belong to Interior patterns. Cold belongs to Yin. It can be Internal Cold or External Cold; Cold patterns are mostly Deficient. Heat belongs to Yang. It can be Internal Heat or External Heat; Heat patterns are mostly Excessive. Deficiency refers to insufficient Zheng Qi (Upright Qi); diseases originating from within often manifest as insufficiency. Excess refers to surplus pathogenic factors; diseases entering from outside often manifest as excess. The detailed explanations of these six are listed below.
Exterior patterns refer to diseases caused by pathogenic factors invading from the outside. Any abnormal qi such as wind, cold, summerheat, dampness, fire, and dryness falls into this category. The Classics state: "When clear wind arrives greatly, it indicates an excess of dryness. When wind-wood is affected by pathogens, Liver disease arises." "When heat qi arrives greatly, it indicates an excess of fire. When metal-dryness is affected by pathogens, Lung disease arises." "When cold qi arrives greatly, it indicates an excess of water. When fire-heat is affected by pathogens, Heart disease arises." "When damp qi arrives greatly, it indicates an excess of earth. When cold-water is affected by pathogens, Kidney disease arises." "When wind qi arrives greatly, it indicates an excess of wood. When earth-dampness is affected by pathogens, Spleen disease arises." It is also said: "If one is injured by cold in winter, one will surely suffer from warm diseases in spring. If one is injured by wind in spring, one will suffer from undigested food diarrhea in summer. If one is injured by summerheat in summer, one will surely suffer from coughing and malaria in autumn. If one is injured by dampness in autumn, one will surely suffer from coughing in winter." It is also said: "Wind coming from the Chonghou direction is called Empty Wind, which harms people and is the master of killing and harm." All these statements discuss external pathogenic factors. However, pathogenic factors have a distinction between Yin and Yang, and the sites they damage differ accordingly. Although there are six types of pathogens, their transformation归结s to Yin and Yang. Yang pathogens transform into Heat, and Heat damages Qi; Yin pathogens transform into Cold, and Cold damages the Form. Damaging Qi involves the nose connecting to the internal organs. Thus, when externally affected by summerheat and illness manifests internally, it is because Heat pathogens damaged Qi. Damaging Form affects the skin and hair superficially, and the meridians deeply. Thus, when externally affected by wind and cold and illness manifests as fever and body pain, it is because Cold pathogens damaged Form. The Classics state: "Cold causes the Cou Li (pores) to close and Qi movement to stagnate, so Qi becomes constrained. Heat causes the Cou Li to open, Ying and Wei Qi to circulate freely, leading to profuse sweating, so Qi leaks out." This is the distinction between the Yin and Yang of the Six Qi. However, among the Six Pathogens affecting the exterior, wind and cold are the most common. Wind is the leader of a hundred diseases, and cold is a lethal qi. Internally, humans have Zang-Fu organs; externally, they have Meridians. Whenever pathogenic factors lodge in the form, they first reside in the skin and hair; if not expelled, they enter the Sun Luo (branch collaterals); if not expelled, they enter the Luo Mai (collateral vessels); if not expelled, they enter the Jing Mai (main meridians), then internally connect to the Five Zang organs and scatter to the stomach and intestines. When both Yin and Yang are affected, the Five Zang organs are injured. This is the sequence of pathogens moving from exterior to interior. Since pathogens are at the Exterior, there must be Exterior symptoms. Once Exterior symptoms are present, one must not attack the Interior. If mistakenly attacked, not only is it ineffective, but it may cause Interior deficiency, allowing pathogens to sink deeper due to the void. Once Exterior patterns are clear, Interior patterns can be resolved accordingly. Therefore, distinguishing Exterior patterns requires prior examination.
First, human Zang-Fu organs are inside, and meridians are outside; thus, Zang-Fu are Interior, and meridians are Exterior. At the Exterior level, the hands and feet each have six meridians, totaling twelve Main Meridians. Dividing the twelve meridians by Yin and Yang, the six Yang meridians belong to Fu organs and represent the Exterior; the six Yin meridians belong to Zang organs and represent the Interior. Dividing by hand and foot, the foot meridians are long and distant, running from top to bottom and covering the four limbs, so diseases of the whole body can be examined by palpating them. Hand meridians are short and proximal, entering and exiting between the foot meridians. Therefore, when diagnosing Shanghan (Cold Damage) and exogenous diseases, only the foot meridians are discussed, not the hand meridians. Among the six foot meridians, the three Yang meridians are Exterior, and the three Yin meridians are Interior. Among the three Yang meridians, Taiyang is the Exterior of Yang because its meridian runs on the back, which is Yang. Yangming is the Interior of Yang because its meridian runs on the abdomen, which is Yin. Shaoyang is Half-Exterior Half-Interior because its meridian runs on the sides. After the three Yang meridians transmit fully, they gradually enter the three Yin meridians. Thus, to examine Exterior patterns, one should distinguish front, back, left, and right, focusing mainly on the three foot-Yang meridians. Among the three Yang meridians, the Taiyang meridian covers the shoulders and back, serving as the framework for the entire body externally and connecting to the Huang-Mo (diaphragm/membranes) of the five Zang and six Fu organs internally. It is the primary Qi of all Yang meridians, like a major intersection with roads extending in all directions. Therefore, when wind and cold injure humans, they usually start from the Taiyang meridian.
Second, the three foot-Yin meridians run from the feet up to the abdomen. Although they are between the muscles and skin, the three Yin meridians govern the Interior. Furthermore, whenever wind and cold invade from the Exterior, they do not enter the Yin divisions without passing through the Yang meridians. If they bypass the Yang meridians and directly enter the three Yin meridians, it is called Direct Transmission to Yin Meridians (Zhi Zhong), involving the Zang organs. Therefore, Yin meridians lack reliable Exterior symptoms.
Third, when Cold pathogens are at the Exterior, there is invariably fever without sweat, because the pathogens block the skin and hair.
Fourth, when Cold pathogens lodge in the meridians, there is invariably body pain, or stiffness and soreness, because the pathogens disrupt Ying Qi and impede blood vessel circulation.
Fifth, when Cold pathogens are at the Exterior causing headache, four meridians are involved. The Foot-Taiyang meridian flanks the vertex; the Foot-Yangming meridian ascends to Touwei; the Foot-Shaoyang meridian ascends to the temporal angles; the Foot-Jueyin meridian converges at the vertex. All can cause headaches. Therefore, only the Taiyin and Shaoyin meridians do not present with headaches.
Sixth, Cold pathogens at the Exterior often involve aversion to cold. Those injured by it inevitably dislike it, just as those injured by food dislike food, and those injured by cold dislike cold.
Seventh, when pathogens are at the Exterior, the pulse is invariably tight and rapid, because Ying Qi is disturbed by the pathogens.
Eighth, the Taiyang meridian originates from the inner canthus, ascends to the vertex, descends to the nape, and runs alongside the spine to the waist. Therefore, when pathogens are in the Taiyang meridian, there is invariably aversion to cold and fever, accompanied by headache and neck stiffness, back and spine rigidity, or knee soreness and pain.
Ninth, the Yangming meridian originates below the eyes, follows the face and nose, and runs through the chest and abdomen. Therefore, when pathogens are in the Yangming meridian, there is invariably fever with slight aversion to cold, accompanied by eye pain, nasal dryness, and insomnia.
Tenth, Shaoyang is the Half-Exterior Half-Interior meridian. Its meridian winds around the ears and passes from Jianjing down to the hypochondrium. Therefore, when pathogens are in the Shaoyang meridian, there is invariably fever accompanied by deafness, hypochondriac pain, bitter taste, vomiting, or alternating chills and fever.
The above are all Exterior patterns of the three Yang meridians. As long as Exterior patterns are present, one must not attack the Interior. One may use methods to release the Exterior, slightly resolve, warm-disperse, cool-disperse, or warm the Middle and support the Interior to achieve dispersion without dispersing, or tonify Yin to assist Yin to achieve dispersion like clouds evaporating and rain transforming. Alas! The meaning lies in mental comprehension and is hard to express fully. Only the wise can understand it intuitively.
Eleventh, regarding the pulse of Exterior patterns. Zhang Zhongjing said: "The Cun Kou pulse is floating and tight. Floating indicates wind, tight indicates cold. Wind injures Wei Qi, cold injures Ying Qi. When both Ying and Wei are diseased, causing bone and joint discomfort, one should induce sweating." The *Mai Jing* notes: "Wind is Yang, cold is Yin; Wei is Yang, Ying is Yin. Wind injures Yang, cold injures Yin, each injuring according to its kind. Thus, Wei becomes hot when affected by wind, Ying becomes painful when affected by cold. When both Ying and Wei are diseased, bone and joint discomfort results. One should induce sweating to resolve the Exterior and recover."
Twelfth, although a floating pulse inherently belongs to the Exterior, this is not absolute. In cases of severe initial exposure to cold pathogens, the Wei Qi is constrained, and the pulse cannot reach the surface, resulting in a deep and tight pulse. In such cases, one must combine the observation with Exterior symptoms like fever and body pain to distinguish it. Additionally, in cases of blood deficiency causing blood movement, the pulse is invariably large and floating. In cases of Yin deficiency and water depletion, the pulse is invariably large and floating. In cases of blazing internal fire, the pulse is invariably large and floating. In cases of Guan Ge (blockage) with Yin repelling Yang, the pulse is invariably large and floating. In all these cases, one cannot simply attribute a floating pulse to the Exterior. One must consider physical constitution, disease qi, and the presence or absence of external symptoms. If a non-Exterior pattern is mistaken for an Exterior pattern, death can occur in the blink of an eye.
Thirteenth, in exogenous cold pathogens, a large pulse indicates disease progression due to increasing pathogenic strength. However, the pulse must be large and tight to indicate progression. If the pulse was initially small and becomes large, or gradually becomes larger and slower, this indicates a shift from Yin to Yang, representing the gradual return of Stomach Qi and a sign of impending resolution.
Fourteenth, if Cold pathogens are unresolved and the pulse is tight but forceless, there is no hope of recovery. Why? Tightness indicates pathogenic factors; force indicates Yuan Qi (Original Qi). A tight but forceless pulse means excess pathogens and deficient Original Qi. With deficient Original Qi, how can pathogens be expelled? In such cases, one must ensure the gradual replenishment of Yuan Yang. Then the pulse will gradually become forceful, changing from small to large, from weak to solid, eventually becoming surging and slippery. As Yang Qi gradually reaches the surface, the Exterior will resolve. If the pulse becomes increasingly forceless while tightness and rapidity advance daily, it is a sign of critical danger and death.
Fifteenth, a disease must originate from the Exterior to be called an Exterior pattern. If it spreads from the Interior to the Exterior, it is not an Exterior pattern. The Classics state: "For diseases moving from Interior to Exterior, regulate the Interior. For diseases moving from Exterior to Interior, treat the Exterior." If a disease originates internally but manifests severely externally, treat the Interior first, then the Exterior. If a disease originates externally but manifests severely internally, treat the Exterior first, then regulate the Interior. This principle of priority between Interior and Exterior must be known.
Sixteenth, Shangfeng (Wind Injury) and Zhongfeng (Wind Stroke), despite both having "wind" in their names, should not both be treated as Exterior patterns. Shangfeng involves wind entering from the outside and can be treated with dispersing and warming methods; this is an Exterior pattern. Zhongfeng, although resembling wind symptoms, is actually caused by internal injury. There is no external pathogen, so it should not be treated as an Exterior pattern. See the specific section for treatment methods.
Seventeenth, fever-like symptoms are essentially Fire patterns, but one must distinguish between Exterior and Interior. When pathogens are at the Exterior causing fever, it is Exterior Heat without Interior Heat, caused by Cold pathogens; treatment should focus on dissipation. When pathogens are at the Interior causing fever, Interior Heat is severe first and then affects the Exterior; this is a Fire pattern, and treatment should focus on cooling. Both internal and external cases can be discussed under Exogenous Heat. However, bone-steaming night fever due to Yin deficiency and water depletion is Deficient Heat. It should not be treated as Exogenous Heat; instead, strengthening Water and nourishing Yin is required.
Eighteenth, Dampness and Dryness, though categories of external pathogens, each have Yin and Yang aspects. Dampness following Yin is Cold-Dampness; dampness following Yang is Damp-Heat. Dryness following Yang is due to Fire; dryness following Yin arises from Cold. Heat damages Yin and connects to the Zang organs. Cold damages Yang and connects to the meridians. This is why Dampness and Dryness both have Exterior and Interior distinctions that must be clarified for treatment.
Nineteenth, distinguishing Dampness patterns requires differentiating Exterior and Interior. The Classics state: "Affected by dampness, the head feels wrapped." Also: "Those injured by dampness, the lower part is affected first." Walking in wind and rain or working hard until clothes are soaked with sweat represents dampness entering from the outside. Indulging in alcohol, raw, and cold foods leading to diarrhea, jaundice, and swelling represents dampness arising from the inside. For dampness located upper and external, mild diaphoresis is suitable. For dampness located lower and internal, promoting urination is suitable. Damp-Heat should be cleared and drained; Cold-Dampness should be treated by tonifying the Spleen and warming the Kidneys.
Twentieth, distinguishing Dryness patterns also involves Exterior and Interior. The Classics state: "Clear qi arrives greatly, indicating an excess of dryness. Wind-wood is affected, and Liver disease arises." This belongs to Zhongfeng. Generally, excessive dryness leads to Yin deficiency, and Yin deficiency leads to blood shortage, causing traction, stiffness, wasting of skin and pores, or dryness and constipation of Zang-Fu organs. This is Dryness transforming via Yang, with insufficient Ying Qi and internal damage. Treatment should focus on nourishing Ying and tonifying Yin. If Autumn energy is excessive, Metal qi prevails, and wind follows, the Lung is affected first. This belongs to Shangfeng. Cold and wind bind externally, affecting the skin and hair, causing fever without sweat, coughing and wheezing, nasal congestion and hoarseness, or dry throat. This is Dryness generated via Yin, with Wei Qi affected and external damage. Treatment should focus on light, ascending, warming, and dispersing agents to warm the Lung and dispel cold.