论曰∶四时皆有伤寒，治之不可一概论也。冬时气寒，腠理微密，非辛甘温不可，故以桂枝等汤以治之。然风与
寒常相因，寒伤荣，恶寒头痛，脉浮紧而无汗，则用麻黄汤，开发腠理以散邪，得汗即愈。风则伤卫，头痛恶风，
脉浮缓而自汗，则用桂枝汤，克塞腠理以散邪，汗止即愈。经云∶辛甘发散为阳者是也。若夫荣卫俱伤，又非此二汤
所能治也。须大青龙汤，然此汤太峻，又非庸俗所可拟也，予亦有代之者。盖冬时为正伤寒，天气严凝，风寒猛
烈，触冒之者，必宜用辛温散之。其非冬时，亦有恶寒头疼之证，皆宜辛凉之剂，通表里和之，则愈矣。若以冬时所用
桂枝辛温之药通治之，则杀人多矣。曰辛凉者何？羌活冲和汤是也，兼能代大青龙为至稳，呜呼！一方可代三
方危险之药。
按∶辨寒温暑药甚明，冲和一汤，尤为温凉二证穿杨之剂，百发百中者也。
论曰∶《活人书》发于温病曰∶阳热未盛，为寒所制，岂有伏寒既已变而为温？尚可言寒，能制其阳热耶？又于热
病曰∶阳热已盛，寒不能制，亦不当复言其为寒也。盖是春夏阳热已变其伏寒，即非有寒能制其阳热耳，外有寒邪，能
折阳气者，乃是时行寒疾，仲景所谓春分以后，秋分节前，天有暴寒，为时行寒疫是也。三月四月，其时阳气尚弱，为
寒
所折，病热则轻。五月六月，阳气已盛，为寒所折，病热则重。七月八月，阳气已衰，为寒所折，病热亦微。是知时行
寒
疾，与温热二病所论阳气盛衰时月则同。至于论暴寒之寒，与伏寒已变之寒，自是相违，名不正则言不顺矣。张仲景又
云∶其病与温及暑病相似，但治有殊耳。要在辨其病源，寒热温三者之殊，则用药之冷热判然矣。
按∶南阳发变字，大有慧心，至于伏寒之误，南翁亦灼然知其然，而不敢明攻其非，恐起袭闻者议耳。乃亦为非时
寒
疾，以破其惑，始自东垣设寒疫一款，皆可羽翼《内经》，启蒙万世也。
论曰：四季都有伤寒，但治疗时不能一概而论。冬季气候寒冷，人体腠理（皮肤毛孔及其附属组织）致密，非用辛甘温性的药物不可，所以用桂枝汤等方剂来治疗。然而风邪与寒邪常相互影响，若寒邪伤及营血（运行于脉中的精气），出现怕冷、头痛、脉象浮紧且无汗的症状，则使用麻黄汤，以开发腠理来驱散邪气，出汗后病即痊愈。若风邪伤及卫气（行于脉外，具有防御作用的精气），出现头痛、怕风、脉象浮缓且自汗的症状，则使用桂枝汤，以固护腠理来驱散邪气，汗止后病即痊愈。《内经》说：“辛味和甘味的药物配合能发散阳气”，说的就是这个道理。至于营卫同时受伤的情况，就不是这两张方剂所能治疗的了。必须使用大青龙汤，但这张方药力太猛烈，不是普通医生所能轻易拟定的，我也有替代它的方子。因为冬季是真正的伤寒，天气严寒凝滞，风寒猛烈，触犯冒犯的人，必定应当用辛温的药物来发散。如果不是在冬季，也有怕冷、头痛的症状，都适宜用辛凉的药剂，疏通表里调和身体，病就能好。如果用冬季所用的桂枝这种辛温的药物来通治这些情况，就会造成很多死亡。什么叫辛凉呢？就是羌活冲和汤，它兼能替代大青龙汤，是最稳妥的，唉！一张方子可以替代三张危险药物的功效。
按语：辨别寒证和温暑证的用药非常明确，冲和汤这一张方子，更是治疗温证和凉证的精准之剂，百发百中。
论曰：《活人书》在论述温病时说：“阳热尚未旺盛，被寒邪所遏制”，难道潜伏的寒邪既然已经转变为温病，还能说是寒邪吗？还能说是寒邪制约其阳热吗？又在论述热病时说：“阳热已经旺盛，寒邪不能制约”，也不应当再说它是寒邪了。大概是因为春夏季节阳气已变，潜伏的寒邪已去，并不是有寒邪能制约其阳热罢了。外感寒邪，能够折损阳气的，那是时行寒疾，也就是张仲景所说的春分以后、秋分以前，天气突然寒冷，称为时行寒疫。三月四月，此时阳气尚弱，被寒邪折损，患病发热则较轻。五月六月，阳气已盛，被寒邪折损，患病发热则较重。七月八月，阳气已衰，被寒邪折损，患病发热也轻微。由此可知，时行寒疾与温热二病所论述的阳气盛衰与时月的关系是相同的。至于论述暴寒之寒，与潜伏寒邪已转变之寒，自然是相违背的，名分不正那么言语就不顺当。张仲景又说：“这种病与温病及暑病相似，但治疗方法不同。”关键在于辨别疾病的源头，寒、热、温三者之间的区别，那么用药的冷与热就判然不同了。
按语：南阳先生（张仲景）提出“变”字，大有智慧，至于对伏寒理论的误解，南翁（叶天士）也清楚地知道其错误，但不敢公然攻击其非议，恐怕引起袭用旧闻者的议论罢了。于是也将此归为非时行的寒疾，以破除人们的困惑，这始于李东垣设立“寒疫”一门，都可以作为《内经》的辅助，启蒙后世万代。
Translation:
It is said that cold damage (Shanghan, a category of febrile diseases caused by exogenous pathogens) occurs in all four seasons, but its treatment cannot be generalized. In winter, the climate is cold, and the cou li (skin pores and interstitial spaces) are tight and dense; therefore, acrid-sweet-warm herbs are indispensable, so Guizhi Tang (Cinnamon Twig Decoction) and similar formulas are used for treatment. However, wind and cold pathogens often influence each other. If cold damages the Ying blood (nutritive qi circulating within the vessels), presenting with aversion to cold, headache, a floating-tight pulse, and absence of sweating, Mahuang Tang (Ephedra Decoction) is employed to open the cou li and disperse the pathogen; recovery follows once sweating occurs. If wind damages the Wei qi (defensive qi circulating outside the vessels), presenting with headache, aversion to wind, a floating-slow pulse, and spontaneous sweating, Guizhi Tang is used to secure the cou li and disperse the pathogen; recovery follows once sweating ceases. The Classics state: "Acrid and sweet substances act as Yang to disperse," which refers to this principle. As for cases where both Ying and Wei are damaged, these two formulas are insufficient. Da Qinglong Tang (Major Blue Green Dragon Decoction) must be used. However, this formula is too potent and not suitable for average practitioners; I have devised alternatives. Winter represents true Shanghan, when the weather is severely cold and frozen, and wind-cold is fierce. Those who contract it must be treated with acrid-warm herbs to disperse. Outside of winter, patients may also present with aversion to cold and headache; these should be treated with acrid-cool agents to unblock the exterior and harmonize the interior, leading to recovery. Using acrid-warm herbs like those in Guizhi Tang, intended for winter, to treat such conditions indiscriminately would result in many deaths. What constitutes acrid-cool? It is Qianghuo Chonghe Tang (Notopterygium Harmonizing Decoction). This formula can safely substitute for Da Qinglong Tang. Alas! One formula replaces three dangerous ones.
Commentary: The differentiation of medications for cold versus warm-summer diseases is very clear. Chonghe Tang is particularly an accurate remedy for both warm and cool syndromes, effective in every instance.
It is said: *Huo Ren Shu* (Book of Vitality) states regarding warm disease: "Yang heat is not yet abundant, constrained by cold." But if latent cold has already transformed into warm disease, how can it still be called cold? How can it be said that cold constrains Yang heat? Furthermore, regarding heat disease: "Yang heat is already abundant, and cold cannot constrain it"; thus, it should no longer be referred to as cold. Generally, in spring and summer, Yang heat transforms the latent cold; there is no cold capable of constraining Yang heat. External cold pathogens that can injure Yang Qi constitute "epidemic cold illness" (Shixing Hanji). This is what Zhang Zhongjing described as "epidemic cold plague" (Shixing Hanyi): sudden cold weather after the Spring Equinox and before the Autumn Equinox. In the third and fourth lunar months, Yang Qi is still weak; when constrained by cold, the resulting fever is mild. In the fifth and sixth months, Yang Qi is abundant; when constrained by cold, the resulting fever is severe. In the seventh and eighth months, Yang Qi is declining; when constrained by cold, the resulting fever is also slight. Thus, it is known that the discussion on the waxing and waning of Yang Qi in epidemic cold illness aligns with that of warm and heat diseases. However, the discussion on the cold of sudden cold differs from the cold of latent cold that has already transformed; they are contradictory. If names are incorrect, speech does not flow smoothly. Zhang Zhongjing further stated: "The disease resembles warm disease and summerheat disease, but the treatment differs." The key lies in differentiating the disease source; distinguishing between cold, heat, and warm allows one to clearly determine whether to use cold or hot medications.
Commentary: Mr. Nanyang (Zhang Zhongjing) introduced the character "transform" (Bian), demonstrating great wisdom. Regarding the misconception of latent cold, Nan Weng (Ye Tianshi) clearly recognized the error but dared not openly refute it, fearing criticism from those adhering to traditional views. Instead, he categorized it as non-seasonal cold illness to dispel confusion. This originated with Li Dongyuan establishing the category of "cold plague," which serves to support the *Neijing* (Inner Canon) and enlighten future generations.