仲景六经辨证之法。与内经不尽相合。余尝深思之而不得其解。及读程郊倩伤寒后条辨
。其
贬驳叔和序例内。有一段入理深谭。殊为可采。内经云。热病者皆伤寒之类也。着一类字。
见热病特伤寒中之一类耳。然类而不类。亦不类而类。盖同此六经。而病因之寒热有不同。
如一日巨阳受之。头项痛腰脊强。类也。其不类者。恶寒与不恶寒也。二日阳明受之。身热
目痛鼻干不得眠。类也。其不类者。伤寒入胃。热病不入胃。入胃则不传故也
。三日少阳受之。胸胁痛而耳聋。类也。其不类者。伤寒有往来寒热。热病但有半里之热
。
而无半表之寒也。伤寒三阴证。有寒热错杂之不齐。热病则但有热而无寒。四日太阴受之。
则腹满嗌干。全不类。伤寒腹满吐利食不下之太阴也。五日少阴受之。则口燥舌干而渴。虽
类伤寒少阴负趺阳之一证。而总不类。伤寒脉微细但欲寐之少阴也。六
日厥阴受之。则烦满而囊缩。在伤寒烦或有之。而却不类。伤寒食不下下即吐蛔之厥阴也。
似此剖晰精详。可称千古只眼。而吾更谓内经之言日数者。使人知其常。仲景之不言日数者
。欲人通其变。学伤寒家。先须打破此疑团。于仲景法始有把握矣。
仲景书以伤寒命名。而首列中风。内经云。风者百病之始也。清静则肉腠闭拒。虽有大风苛
毒。弗之能害。是则中风之为病。多由于腠理之疏。而后风邪得以易袭。故本论云。太阳中
风。阳浮而阴弱。阳浮者热自发。阴弱者汗自出。啬啬恶寒。淅淅恶风。翕翕发热。鼻鸣干
呕者。桂枝汤主之。所言太阳中风之病状。皆就皮毛上形容。邪本由外而入。亟当驱之外出
。但腠理本疏。又不可大发其汗。故仲景桂枝汤之取义。但主调和营卫以解肌表。取其
微
似有汗。不可令如水流漓。方中芍药甘枣。主固营气以托出卫邪。使风邪不敢内入而外出。
然后桂枝合生姜。得建驱邪之续。今人不识此义。改用一派风药。迫之使汗。甚或加辛热之
药。扰动营血。其不致召变逆而成危证者鲜矣。医者可不慎之于始欤。
张仲景的六经辨证方法，与《黄帝内经》中的论述并不完全一致。我曾经深入思考却未能理解其中的缘由。直到阅读程郊倩（程知）所著的《伤寒后条辨》，其中在驳斥王叔和《序例》的部分，有一段分析极为深刻且入理，非常值得采纳。
《内经》说：“热病者皆伤寒之类也。”这里用了一个“类”字，说明热病只是伤寒中的一类罢了。然而，它们既相似又不相似，既不相像又像相像。虽然都涉及这六经，但病因中寒与热的性质有所不同。
例如第一天太阳经受邪，出现头痛、项强、腰脊僵硬，这是相似的；其不相似之处，在于是否恶寒。第二天阳明经受邪，出现身热、目痛、鼻干、不得安眠，这也是相似的；其不相似之处，在于伤寒邪气传入胃腑，而热病则不传入胃腑，因为传入胃腑就不会再传变其他经络了。第三天少阳经受邪，出现胸胁疼痛和耳聋，这也是相似的；其不相似之处，在于伤寒有往来寒热的症状，而热病只有半里的热象，而没有半表的寒象。
伤寒的三阴证，有寒热错杂、参差不齐的情况；而热病则只有热象而没有寒象。第四天太阴经受邪，出现腹满、咽喉干燥，这就完全不相似了。伤寒的太阴病是腹满、呕吐、下利、饮食不下。第五天少阴经受邪，出现口燥、舌干而渴，虽然这与伤寒少阴病中脉微细、但欲寐的一种证候有点类似，但总体还是不相似。第六天厥阴经受邪，出现心烦、胀满和阴囊收缩，这在伤寒中或许会有心烦，但总体还是不相似。伤寒的厥阴病是饮食不下，吃下去就吐蛔虫。
像这样剖析清晰、详尽透彻，可以称为千古独到的见解。而我更进一步认为，《内经》提到日数，是为了让人了解常规情况；张仲景不提日数，是为了让人通晓变化之法。学习伤寒的人，必须先打破这个疑惑，对张仲景的方法才能有所把握。
张仲景的书以“伤寒”命名，却在开篇首先列出“中风”。《内经》说：“风者百病之始也。”如果人体清静无扰，肌肉腠理就会闭合抵御外邪，即使有大风剧毒，也不能伤害人体。由此可见，中风这种病，多是由于腠理疏松，导致风邪容易侵袭。所以《本论》中说：“太阳中风，阳浮而阴弱。阳浮者热自发，阴弱者汗自出。啬啬恶寒，淅淅恶风，翕翕发热，鼻鸣干呕者，桂枝汤主之。”这里所说的太阳中风的病症表现，都是针对皮毛层面描述的。邪气本来是从外部侵入的，应当迅速将其驱除外出。但是，由于腠理原本就疏松，又不宜大发其汗。因此，张仲景使用桂枝汤的用意，主要在于调和营卫以解肌表之邪，取其微微似有出汗的效果，不可让汗水像水流一样淋漓不止。方中的芍药、甘草、大枣，主要作用是固护营气，从而托举卫分之邪外出，使风邪不敢内侵而向外排出。然后桂枝配合生姜，得以建立持续驱邪的力量。如今的人不认识这个道理，改用一派风药，逼迫患者出汗，甚至加入辛热药物，扰动营血，这样不导致病情变化逆乱而成危重证的，是很少见的。医生们难道不在开始时谨慎对待吗？
The method of Six-Meridian differentiation in Zhang Zhongjing's work does not fully align with the discussions in the *Huangdi Neijing* (Yellow Emperor's Inner Canon). I once pondered this deeply but could not find an explanation. It was only after reading Cheng Jiaoqian's (Cheng Zhi) *Shanghan Hou Tiaobian* (Differentiation of Post-Strain Cold Sequelae) that I encountered a passage refuting Wang Shuhe's "Preface to the Examples," which offered profound and logical analysis, highly worthy of adoption.
The *Neijing* states: "All heat diseases belong to the category of cold damage." The use of the word "category" indicates that heat disease is merely one type within cold damage. However, they are both similar and dissimilar; they resemble each other yet do not. Although both involve the Six Meridians, the etiological factors of cold and heat differ.
For instance, on the first day, the Taiyang Meridian (Greater Yang Meridian) is affected, presenting with headache, stiffness of the neck and back, and rigidity of the waist and spine; this is similar. The dissimilarity lies in the presence or absence of aversion to cold. On the second day, the Yangming Meridian (Yang Brightness Meridian) is affected, presenting with fever, eye pain, dry nose, and insomnia; this is also similar. The dissimilarity lies in the fact that in cold damage, the pathogen enters the Stomach, whereas in heat disease, it does not enter the Stomach, because entering the Stomach prevents further transmission to other meridians. On the third day, the Shaoyang Meridian (Lesser Yang Meridian) is affected, presenting with hypochondriac pain and deafness; this is similar. The dissimilarity lies in the fact that cold damage presents with alternating chills and fever, while heat disease presents only with heat in the interior half (half-li), without cold in the exterior half (half-biao).
In the Three Yin syndromes of cold damage, there is a complex mixture of cold and heat, varying irregularly; whereas in heat disease, there is only heat and no cold. On the fourth day, the Taiyin Meridian (Great Yin Meridian) is affected, presenting with abdominal fullness and dry throat; this is completely dissimilar. The Taiyin syndrome of cold damage involves abdominal fullness, vomiting, diarrhea, and inability to eat. On the fifth day, the Shaoyin Meridian (Lesser Yin Meridian) is affected, presenting with dry mouth, dry tongue, and thirst; although this resembles one aspect of Shaoyin cold damage where the pulse is faint and fine and the patient desires sleep, overall it remains dissimilar. On the sixth day, the Jueyin Meridian (Terminal Yin Meridian) is affected, presenting with vexation, fullness, and retraction of the testicles; while vexation may occur in cold damage, overall it is dissimilar. The Jueyin syndrome of cold damage involves inability to eat and vomiting roundworms immediately after eating.
Such detailed and precise analysis can be called a unique insight through the ages. I would further argue that the *Neijing*'s mention of days serves to inform people of the constant patterns, while Zhang Zhongjing's omission of days aims to teach people to understand variations. Those studying cold damage must first break through this confusion to gain mastery over Zhang Zhongjing's methods.
Zhang Zhongjing's book is named *Shanghan Lun* (Treatise on Cold Damage), yet it lists Wind Strike (Zhong Feng) at the beginning. The *Neijing* states: "Wind is the beginning of all diseases." If the body remains calm and pure, the muscle pores (Cou Li) will close and resist external pathogens; even severe wind toxins cannot harm it. Thus, Wind Strike often arises from loose Cou Li, allowing wind pathogens to easily invade. Therefore, the *Benlun* (Original Treatise) states: "Taiyang Wind Strike, with floating Yang and weak Yin. Floating Yang causes spontaneous heat; weak Yin causes spontaneous sweating. With shivering aversion to cold, chilly aversion to wind, mild fever, nasal congestion, and dry retching, Guizhi Tang (Cinnamon Twig Decoction) should govern it." The described symptoms of Taiyang Wind Strike are all characterized based on the skin and hair level. Since the pathogen enters from the exterior, it must be driven out urgently. However, since the Cou Li are inherently loose, excessive sweating should not be induced. Therefore, the rationale for using Guizhi Tang by Zhang Zhongjing is primarily to harmonize Ying (Nutritive Qi) and Wei (Defensive Qi) to release the muscle layer. It seeks a slight perspiration, not profuse sweating like flowing water. In the formula, Shaoyao (Paeoniae Radix Alba), Gancao (Glycyrrhizae Radix), and Dazao (Jujubae Fructus) mainly secure Ying Qi to push out Wei pathogens, preventing wind pathogens from invading internally and facilitating their exit. Then, Guizhi (Cinnamomi Ramulus) combined with Shengjiang (Zingiberis Rhizoma Recens) establishes continuous power to expel pathogens. Modern practitioners who fail to understand this principle often replace it with a batch of wind-dispelling herbs, forcing sweat, or even adding acrid-hot drugs, disturbing Ying and Blood. Rarely do such cases avoid causing adverse changes leading to critical conditions. Should not physicians exercise caution at the outset?