成无己注伤寒论。有云。四逆者。四肢不温也。厥者。手足冷也。伤寒邪在三阳。则手足必
热。传到太阴。手足自温。至少阴。则邪热渐深。故四肢逆而不温。及至厥阴。则手足厥冷
。是又甚于逆。经曰。少阴病。四逆。其人或咳。或悸。或小便不利。或腹中痛。或泄痢下
重者。四逆散主之。方用柴胡枳实芍药甘草。四者皆寒冷之物。而专主四逆之疾。是知四逆
非虚寒之证也。四逆与厥相近而非。经曰诸四逆厥者。不可下。是四逆与厥有异也。吁。斯
言也。所谓弥近理而大乱真者欤。窃尝考之。仲景言四逆与厥者非一。或曰四逆。或曰厥。
或曰厥逆。或曰厥冷。或曰厥寒。或曰手足逆冷。
或曰手足厥逆。或曰手足厥冷。或曰手足厥逆冷。细详其义。俱是言寒冷耳。故厥逆二字。
每每互言。未尝分逆为不温。厥为冷也。然四肢与手足却
有所分。其以四字加于逆字之上者。是通指手足臂胫以上言也。其以手足二字加于厥逆厥冷
等之上。及无手足二字者。是独指手足言也。既曰不温。即为冷矣。尚何异乎。仲景所谓诸
四逆厥者。不可下。盖以四逆。为四肢通冷。厥为手足独冷。而臂与胫以上不冷耳。不谓逆
厥。有不温与冷之别也。故又曰。厥者手足逆冷是也。以逆冷二字释厥字。足见逆即厥。厥
即逆也。故字书曰。厥者逆也。虽然。逆厥虽俱为寒冷。而却有阴阳之殊焉。热极而成逆
厥者。阳极似阴也。寒极而成逆厥者。独阴无阳也。阳极似阴。固用寒药。独阴无阳。固用
热药。仲景以四逆散寒药治四逆一条。此阳极似阴之四逆也。其无四逆汤热药治四逆之条者
。安知其非本有而失之乎。且四逆汤之名。由四肢之冷而立也。今以四逆汤治手足厥冷。岂
非逆厥之不异乎。既以四逆为四肢不温。厥为手足独冷。何故不名治厥之药为四厥汤乎。成
氏于四逆散治四逆条下。谓。四逆为热邪所为。及于明理论。谓。四逆非虚寒之证矣。至于
少阴病死证二条下。却谓。四逆为寒甚。君此者得不自悖其说乎。是知四逆亦犹厥之有寒有
热。固不可谓四逆。专为热邪所作也。但四肢通冷。比之手足独冷。则有间尔。故仲景曰。
少阴病。吐利。躁烦。四逆者。死。又曰。少阴病。四逆。恶寒而身蜷。脉不至。不烦而躁
者。死。又曰。少阴病。吐利。手足厥冷。烦躁欲死者。吴茱萸汤主之。此三条者。二为死
。一为可治。虽通由诸证兼见而然。然死者以四逆言。可治者以厥冷言。则亦可见。四逆
与
手足厥冷之有轻重浅深矣。夫四肢通冷。其病为重。手足独冷。其病为轻。虽妇人小子亦能
知之。成氏乃谓厥甚于逆。何邪。若能知四逆厥之所以异者。在于独指手足言。与兼指臂胫
以上言。则不劳创为不温与冷之曲说。而自然贯通矣。
Cheng Wuji, in his commentary on the *Shanghan Lun* (Treatise on Cold Damage), stated: "Si Ni (Four Extremities Reversal/Coldness) refers to the limbs being not warm; Jue (Reversal/Extremity Coldness) refers to the hands and feet being cold." He believed that when pathogenic factors of cold damage are in the Three Yang meridians, the hands and feet must be hot; when transmitted to the Taiyin meridian, the hands and feet naturally become warm; upon reaching the Shaoyin meridian, the pathogenic heat deepens gradually, thus causing the four extremities to reverse and become not warm; arriving at the Jueyin meridian, the hands and feet become completely cold. This is more severe than "Ni" (Reversal). The classic states: "In Shaoyin disease, if Si Ni occurs, and the patient experiences cough, palpitations, difficulty in urination, abdominal pain, or dysentery with a sensation of heaviness in the anus, Si Ni San (Four Extremities Reversal Powder) should be used as the primary treatment." The formula consists of Chai Hu (Bupleuri Radix), Zhi Shi (Aurantii Fructus Immaturus), Shao Yao (Paeoniae Radix Alba), and Gan Cao (Glycyrrhizae Radix et Rhizoma). These four herbs are all cold-natured substances, yet they specifically treat the condition of Si Ni. From this, it can be known that Si Ni is not a deficiency-cold syndrome. "Si Ni" and "Jue" are similar in name but different in essence. The classic states: "For those presenting with various forms of Si Ni or Jue, purgation methods should not be used." This indicates that Si Ni and Jue are distinct. Alas! This statement is precisely what is meant by "appearing plausible yet fundamentally distorting the truth."
I have carefully examined the texts, and Zhang Zhongjing mentions Si Ni and Jue on numerous occasions. Sometimes he says "Si Ni," sometimes "Jue," sometimes "Jue Ni," sometimes "Jue Leng," sometimes "Jue Han," sometimes "Shou Zu Ni Leng," sometimes "Shou Zu Jue Ni," sometimes "Shou Zu Jue Leng," and sometimes "Shou Zu Jue Ni Leng." Upon detailed examination of their meanings, they all refer to coldness. Therefore, the terms "Jue Ni" are often used interchangeably, never distinguishing "Ni" as merely not warm and "Jue" as cold. However, there is indeed a distinction between "Si Zhi" (four limbs) and "Shou Zu" (hands and feet). When the character "Si" (four) is placed before "Ni" (as in Si Ni), it generally refers to the entire limb region, including hands, feet, arms, and calves. When "Shou Zu" (hands and feet) is added before terms like "Jue Ni" or "Jue Leng," or when "Shou Zu" is omitted entirely, it specifically refers only to the hands and feet. Since "not warm" implies coldness, what difference remains?
Zhang Zhongjing's statement that "various cases of Si Ni and Jue should not be purged" likely stems from the understanding that "Si Ni" refers to coldness throughout the four limbs, whereas "Jue" refers specifically to coldness isolated to the hands and feet, while the arms and calves above remain uncold. He did not intend to distinguish between "Ni" and "Jue" based on degrees of warmth versus cold. Thus, he further clarified: "What is called Jue is precisely the reversal coldness of the hands and feet." By using the term "reversal coldness" (Ni Leng) to explain "Jue," it is evident that "Ni" is equivalent to "Jue," and "Jue" is equivalent to "Ni." Hence, dictionaries state: "Jue means Ni." Although both Ni and Jue manifest as coldness, they differ in Yin and Yang nature. Reversal coldness caused by extreme heat represents "Yang extreme resembling Yin"; reversal coldness caused by extreme cold represents "Yin extreme without Yang." Cases of Yang extreme resembling Yin naturally require cold-natured medicines; cases of Yin extreme without Yang naturally require hot-natured medicines. Zhang Zhongjing’s use of Si Ni San (a cold-natured formula) to treat Si Ni in one instance refers to Si Ni of the "Yang extreme resembling Yin" type. Regarding the absence of clauses where Si Ni Tang (a hot-natured formula) treats Si Ni, how can we know if such clauses originally existed but were lost? Moreover, the name "Si Ni Tang" is derived from the coldness of the four limbs. If Si Ni Tang is now used to treat hand-foot Jue Leng (coldness), does this not imply that Ni and Jue are indistinguishable? If Si Ni is defined as coldness of the four limbs and Jue as isolated coldness of the hands and feet, why is the medicine for treating Jue not named "Si Jue Tang"?
Cheng Wuji, under the clause for Si Ni San treating Si Ni, claimed that "Si Ni is caused by heat pathogens." In his *Ming Li Lun* (Discussion on Principles), he stated that "Si Ni is not a deficiency-cold syndrome." Yet, under the two clauses regarding fatal Shaoyin diseases, he asserted that "Si Ni is due to extreme cold." Is this not self-contradictory? From this, it is known that Si Ni, like Jue, can involve either cold or heat; it cannot be said that Si Ni is exclusively caused by heat pathogens. There is merely a difference in severity: coldness of the four limbs is more severe than isolated coldness of the hands and feet. Therefore, Zhang Zhongjing stated: "In Shaoyin disease, if vomiting, diarrhea, restlessness, and Si Ni occur, the prognosis is fatal." He also stated: "In Shaoyin disease, if Si Ni occurs accompanied by aversion to cold, body curling up, absent pulse, and restlessness without irritability, the prognosis is fatal." Furthermore: "In Shaoyin disease, if vomiting, diarrhea, hand-foot Jue Leng, and severe irritability occur, Wu Zhu Yu Tang (Evodia Decoction) should be used." Among these three clauses, two indicate fatality, and one indicates treatability. Although this depends on the combination of symptoms, the fatal cases are described using "Si Ni," while the treatable case uses "Jue Leng." This demonstrates the difference in severity and depth between Si Ni and hand-foot Jue Leng. Coldness of the four limbs indicates a heavier disease state; isolated coldness of the hands and feet indicates a lighter disease state. Even women and children understand this. Why did Cheng Wuji claim that "Jue is more severe than Ni"? If one understands that the distinction between Si Ni and Jue lies in whether the reference includes the arms and calves (Si Ni) or is restricted to the hands and feet (Jue), there would be no need to force explanations distinguishing "not warm" from "cold," and the concepts would naturally align.