或曰∶子言伤寒与时疫有霄壤之隔，今用三承气，及桃仁承气、抵当、茵陈诸汤
，皆伤寒方也，既用其方，必同其证，子何言之异也？曰∶夫伤寒必有感冒之因，或单衣风
露，或强力入水，或临风脱衣，或当檐出浴，当觉肌肉粟起，既而四肢拘急，恶风恶寒，然
后头疼身痛，发热恶寒，脉浮而数，脉紧无汗为伤寒，脉缓有汗为伤风。时疫初起，原无
感冒之因，忽觉凛凛，以后但热而不恶寒，然亦有所触因而发者，或饥饱劳碌，或焦思气郁，
皆能触动其邪，是促其发也。不因所触无故自发者居多，促而发者，十中之一二耳。且伤寒
投剂，一汗而解，时疫发散，虽汗不解。伤寒不传染于人，时疫能传染于人。伤寒之邪，自
毫窍而入；时疫之邪，自口鼻入。伤寒感而即发，时疫感久而后发。伤寒汗解在前，时疫
汗解在后。伤寒投剂可使立汗；时疫汗解，俟其内溃，汗出自然，不可以期。伤寒解以发汗
，时疫解以战汗。伤寒发斑则病笃，时疫发斑则病衰。伤寒感邪在经，以经传经；时疫感邪
在内，内溢于经，经不自传。伤寒感发甚暴，时疫多有淹缠二三日，或渐加重，或淹缠五六
日，忽然加重。伤寒初起，以发表为先，时疫初起，以疏利为主。种种不同。其所同者，伤
寒时疫皆能传胃，至是同归于一，故用承气汤辈，导邪而出。要之，伤寒时疫，始异而终同也
。夫伤寒之邪，自肌表一径传里，如浮云之过太虚，原无根蒂，惟其传法，始终有进而无退
，故下后皆能脱然而愈。时疫之邪，始则匿于膜原，根深蒂固，发时与营卫交并，客邪经由
之处，营卫未有不被其所伤者，因其伤，故名曰溃。然不溃则不能传，不传邪不能出，邪
不出而疾不瘳。时疫下后，多有未能顿解者，何耶？盖疫邪每有表里分传者，因有一半向外
传，则
，于是肌肉之邪，不能即达于肌表，下后里气一通，表气亦顺，向者郁于肌肉之邪，方能尽发于
肌表，或斑或汗，然后脱然而愈，伤寒下后无有此法。虽曰终同，及细较之，而终又有不同者矣
。
或曰∶伤寒感天地之正气，时疫感天地之戾气，气既不同，俱用承气，又何药之相同也？曰
∶风寒疫邪，与吾身之真气，势不两立，一有所着，气壅火积，气也，火也，邪也，三者混
一，与之俱化，失其本然之面目，至是均为之邪矣。但以驱逐为功，何论邪之同异也。假如初得
伤寒为阴邪，主闭藏而无汗，伤风为阳邪，主开发而多汗，始有桂枝、麻黄之分，原其感而
未化也，传至少阳，并用柴胡，传至胃家，并用承气，至是亦无复有风寒之分矣。推而广之
，是知疫邪传胃，治法无异也。
有人问：您说伤寒与时疫有天壤之别，如今使用三承气汤，以及桃仁承气汤、抵当汤、茵陈蒿汤等方剂，这些都是治疗伤寒的方子，既然用了这些方子，病情必然相同，为什么您的说法却不同呢？回答说：伤寒必定有感受外邪的原因，比如单衣暴露在风露中，或强力涉水，或在风中脱衣，或在屋檐下洗澡，当时会感觉肌肉起粟粒状鸡皮疙瘩，随后四肢拘挛急迫，怕风怕冷，然后出现头痛身痛，发热恶寒，脉象浮而数，脉紧且无汗为伤寒，脉缓且有汗为伤风。时疫初起，原本没有感冒这样的诱因，忽然觉得寒冷战栗，之后只有发热而不怕冷，但也有因接触某些因素而发作的，比如饥饱不均、劳累忙碌，或思虑过度、气机郁结，都能触动体内的邪气，促使它发作。不因为接触这些因素而无故自发的是大多数，因触动而发作的，十中只有一二罢了。而且伤寒用药，发一次汗就能痊愈；时疫虽然发散，即使出汗也不能痊愈。伤寒不传染给别人，时疫能传染给别人。伤寒的病邪，从毫窍（毛孔）进入；时疫的病邪，从口鼻进入。伤寒感邪后立即发作，时疫感邪后很久才发作。伤寒通过发汗解表在前，时疫通过发汗解表在后。伤寒用药可以立即出汗；时疫的发汗解表，要等待体内邪气溃散，汗出自然，不可以预期。伤寒通过发汗解除病邪，时疫通过战汗解除病邪。伤寒出现发斑则病情危重，时疫出现发斑则病情减轻。伤寒感邪在经络，以经传经；时疫感邪在内，由内溢出到经络，经络之间不互相传变。伤寒感邪发病非常急暴，时疫多有缠绵两三天，或者逐渐加重，或者缠绵五六天，突然加重。伤寒初起，以发表为先，时疫初起，以疏利为主。种种不同。它们相同的地方是，伤寒和时疫都能传入胃腑，到了这个时候，两者归于一途，所以使用承气汤类方剂，引导邪气排出。总之，伤寒和时疫，开始不同而最终相同。伤寒的病邪，从肌表一直传到里，像浮云经过太空，原本没有根基，只是它的传变规律，始终只有进没有退，所以下法之后都能立刻痊愈。时疫的病邪，开始时潜伏在膜原，根深蒂固，发作时与营卫之气交并，客邪经过的地方，营卫没有不被它所伤害的，因为这种伤害，所以叫做“溃”。然而不溃散就不能传变，不传变邪气就不能排出，邪气不排出疾病就不能痊愈。时疫使用下法后，有很多不能立刻痊愈的，为什么呢？大概疫邪常有表里分传的情况，因为有一半向外传，于是肌肉中的邪气，不能立即到达肌表，下法之后里气通畅，表气也顺达，先前郁结在肌肉中的邪气，才能全部发于肌表，或发斑或出汗，然后才立刻痊愈，伤寒下法之后没有这种方法。虽然说最终相同，但仔细比较起来，最终又有不同的地方了。
有人问：伤寒感受天地之正气，时疫感受天地之戾气，气既然不同，都使用承气汤，又为什么药物相同呢？回答说：风寒疫邪，与人体内的真气，势不两立，一旦附着，气壅滞火积聚，气、火、邪三者混为一体，与之同化，失去了本来面目，到了这个时候，都成为邪气了。只要以驱逐邪气为功效，何必讨论邪气的同异呢。假如刚得伤寒属于阴邪，主闭藏而无汗，伤风属于阳邪，主开发而多汗，起初有桂枝汤、麻黄汤的区别，这是因为感邪尚未化热；传到少阳，都用柴胡剂；传到胃家，都用承气汤，到了这个时候，也不再区分风寒了。推而广之，可知疫邪传入胃腑，治疗方法没有差异。
A question was raised: "You stated that Shanghan (Cold Damage) and Shi Yi (Epidemic Febrile Disease) are as different as heaven and earth. Yet, you now utilize San Chengqi Tang (Three Cathartic Decoctions), as well as Taoren Chengqi Tang (Peach Kernel Cathartic Decoction), Didang Tang (Definite Confrontation Decoction), Yinchen Hao Tang (Artemisia Capillaris Decoction), etc., which are all formulas for treating Shanghan. Since you use these formulas, the syndromes must be identical. Why do your statements differ?" The answer is: "Shanghan necessarily has a cause of external contraction, such as wearing thin clothes in wind and dew, forcing oneself into water, taking off clothes in the wind, or bathing under an eaves. At that moment, one feels goosebumps on the skin, followed by stiffness and spasm of the four limbs, aversion to wind and cold. Subsequently, headache and body pain occur, with fever and aversion to cold. A floating and rapid pulse, or a tight pulse without sweat, indicates Shanghan; a slow pulse with sweat indicates Shangfeng (Wind Injury). Shi Yi, at its onset, originally lacks such a cause of common cold. One suddenly feels chilly and shivering, followed by fever without aversion to cold. However, there are cases triggered by contact with certain factors, such as irregular eating, overwork, excessive worry, or qi stagnation, which can stir up the pathogenic factor and promote its eruption. Most cases arise spontaneously without such triggers; only one or two out of ten are promoted by triggers. Furthermore, Shanghan resolves with a single sweating episode, whereas Shi Yi, even after dispersing efforts, does not resolve with sweat. Shanghan is not contagious, while Shi Yi is contagious. The pathogen of Shanghan enters through the hair pores (Hao Qiao); the pathogen of Shi Yi enters through the mouth and nose. Shanghan manifests immediately upon infection, whereas Shi Yi manifests after a long period. For Shanghan, resolving via sweating occurs early; for Shi Yi, it occurs late. Medication for Shanghan can induce immediate sweating; for Shi Yi, sweating occurs naturally only after internal resolution, and cannot be anticipated. Shanghan is resolved through ordinary sweating, whereas Shi Yi is resolved through Zhan Han (Battle Sweat). In Shanghan, the appearance of macules indicates severe disease; in Shi Yi, it indicates improvement. Shanghan involves pathogens affecting the meridians, transmitting from meridian to meridian; Shi Yi involves pathogens residing internally and overflowing into the meridians, without transmission between meridians. Shanghan onset is abrupt; Shi Yi often lingers for two or three days, gradually worsening, or lingers for five or six days before suddenly worsening. At the onset, Shanghan prioritizes releasing the exterior, whereas Shi Yi prioritizes draining and unblocking. There are numerous differences. The similarity lies in that both Shanghan and Shi Yi can transmit to the Stomach. At this stage, they converge, hence the use of Chengqi Tang (Cathartic Decoction) group formulas to guide the pathogen out. In summary, Shanghan and Shi Yi start differently but end similarly. The pathogen of Shanghan transmits directly from the muscle layer to the interior, like clouds passing through the vast sky, originally rootless. Its transmission method always advances and never retreats; thus, after purgation, recovery is immediate. The pathogen of Shi Yi initially hides in the Mo Yuan (Membrane Source), deeply rooted. Upon eruption, it merges with Ying Wei (Nutritive and Defensive Qi). Wherever the exogenous pathogen passes, Ying Wei is inevitably injured; due to this injury, it is termed 'Kui' (Ulceration/Rupture). However, without rupture, transmission cannot occur; without transmission, the pathogen cannot exit; without pathogen exit, the disease does not heal. After purgation in Shi Yi, many cases do not resolve immediately. Why? Because epidemic pathogens often transmit simultaneously to the interior and exterior. If half transmits outward, the pathogen in the muscles cannot immediately reach the muscle surface. After purgation, when the interior qi flows freely, the exterior qi also becomes smooth. The pathogen previously depressed in the muscles can then fully erupt to the muscle surface, either as macules or sweat, leading to immediate recovery. This method does not exist in Shanghan after purgation. Although it is said they are ultimately similar, upon detailed comparison, they remain different.
Another question was raised: "Shanghan contracts the Zheng Qi (Upright Qi) of Heaven and Earth, while Shi Yi contracts the Li Qi (Perverted Qi) of Heaven and Earth. Since the qi differs, why are the same drugs used in Chengqi Tang?" The answer is: "Wind-cold and epidemic pathogens stand in opposition to the Zhen Qi (True Qi) of our body. Once attached, qi becomes stagnant and fire accumulates. Qi, fire, and pathogen mix into one, transforming together, losing their original nature, and becoming pathogenic entities. As long as the goal is to expel them, what difference does it make whether the pathogen is the same or different? Suppose early Shanghan is a Yin pathogen, governing closure and causing no sweat; Shangfeng is a Yang pathogen, governing opening and causing profuse sweat. Initially, there is a distinction between Guizhi Tang (Cinnamon Twig Decoction) and Mahuang Tang (Ephedra Decoction), because the contracted pathogen has not yet transformed. When transmitted to Shaoyang (Lesser Yang), Chaihu (Bupleurum Root) preparations are used universally. When transmitted to the Stomach organ, Chengqi Tang (Cathartic Decoction) is used universally. At this stage, the distinction between wind and cold disappears. Extending this logic, we know that when epidemic pathogens transmit to the Stomach, the treatment method is no different."