《经》曰∶冬伤于寒，春必病温；此言感时气不即发，藏于肤腠之间，过期遇触动而发也。且以即病伤寒，伤风，
与伏气温热病三者而言之。伤寒，则身热无汗恶寒；伤风，则身热有汗恶风。二者皆邪自外入，故表病里和，鼻寒而口
不渴。温热病，则邪自内出，故身热或有汗，或无汗，鼻不寒而口渴也。伤寒，伤风之邪，循经而入以渐而深，故治法
要分三阳三阴清切，表里寒热虚实明白，方可施治，不可一毫而少差也。温热之邪，自内而出，不过发攻表中里三者之
热而已，何难之有哉。（《温热病附论》）
（一）温病者，冬月伏寒之所变也。冬月伏阳在内，感寒不即病，伏藏于肌肤之间，至春时温气将发，又受暴寒，
故春变为温病，既变之后，不得复言为寒矣。又伤寒汗下后，过经不解，亦名温病。并不可发汗，盖过经而发，不在表
也；已经汗下，亦不在表也。《经》曰∶不恶寒而渴者，盖言温病也。不恶寒则病非外来，渴则明其热自内达外，因无
表证明矣。温病之脉行在诸经，不知何经之动，随其经之所在而取之。如太阳病，头痛身热，汗后过经不愈，诊得尺寸
俱浮者，太阳病温也。如身热目疼，汗下后过经不愈，诊得尺寸俱弦长者，阳明病温也。如胸胁痛，汗下后过经不愈，
诊得尺寸俱弦者，少阳病温也。如腹满嗌干，过经不愈，诊得尺寸俱沉者，太阴病温也。如舌干口燥，过经不愈，诊得
尺寸俱微沉者，少阴病温也。如烦满囊缩，过经不愈，诊得尺寸俱微缓者，厥阴病温也。要在随其经而取之。凡温病发
于三阳者多，发于三阴者少。若发于阴，必有所因也，或因饮食内伤而得之，或因欲事先伤肾经而得之。（《温病伤寒第
四十八》）
（二）热病者，冬月伏寒之所变也。冬月伏阳在内，感寒不即病，伏藏于肌肤之间，至夏时暑热将发，又受暴寒，
故夏变为热病。既变之后，不得复言为寒矣。凡热病所起所因所感所发证脉治法，并与温病同。（《热病伤寒第四十九》）
《黄帝内经》说：冬季感受寒邪，到了春天必定发生温病；这是指感受了时行疫气后没有立即发病，而是潜伏在皮肤腠理之间，过了期限遇到触动才发作的。并且以此将即发性伤寒、伤风与伏气温热病这三种情况加以论述。伤寒，表现为身体发热、无汗、怕冷；伤风，表现为身体发热、有汗、怕风。这两者都是邪气从外部侵入，所以是表证而里气平和，鼻子感觉寒冷但口不渴。温热病，则是邪气从内部发出，所以身体发热，有时有汗，有时无汗，鼻子不寒冷但口渴。伤寒和伤风的邪气，沿着经络进入并逐渐深入，所以治疗方法必须严格区分三阳经和三阴经，明确表里、寒热、虚实的区别，才可以实施治疗，不能有一丝一毫的差错。温热病的邪气，从内部发出，不过是发散、攻逐表、中、里三处的热邪罢了，有什么困难呢？（《温热病附论》）
（一）温病，是冬季潜伏的寒邪所转化而成的。冬季阳气潜伏在内，感受寒邪后没有立即发病，潜伏藏匿于肌肤之间，到了春季温暖之气将要发动时，又受到突然袭来的寒气侵袭，所以在春天转化为温病，既然已经转化之后，就不能再说是寒病了。另外，伤寒经过发汗或攻下治疗后，病情超过了一个病程阶段仍未解除，也叫做温病。这两种情况都不可使用发汗法，因为超过病程阶段而发作，病位不在体表；既然已经经过发汗或攻下治疗，病位也不在体表。《黄帝内经》说：不恶寒且口渴的，是说温病。不恶寒说明病邪不是从外而来的，口渴则明确表明热邪是从内部通达外部的，因此没有表证的证据就显而易见了。温病的脉象运行在各条经络中，不知道是哪条经络发生病变，就根据该经络所在的位置来诊察和治疗。例如太阳病，出现头痛、身体发热，发汗后超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都浮的，是太阳经温病。例如身体发热、眼睛疼痛，发汗攻下后超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都弦而长的，是阳明经温病。例如胸胁部疼痛，发汗攻下后超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都弦的，是少阳经温病。例如腹部胀满、咽喉干燥，超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都沉的，是太阴经温病。例如舌干口燥，超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都微沉的，是少阴经温病。例如心烦腹满、阴囊收缩，超过病程阶段仍未痊愈，诊察发现寸关尺三部脉都微缓的，是厥阴经温病。关键在于跟随所属的经络进行诊治。凡是温病发于三阳经的多，发于三阴经的少。如果发于阴经，必定有其原因，或者是由于饮食内伤所致，或者是由于房事过度先损伤肾经所致。（《温病伤寒第四十八》）
（二）热病，也是冬季潜伏的寒邪所转化而成的。冬季阳气潜伏在内，感受寒邪后没有立即发病，潜伏藏匿于肌肤之间，到了夏季暑热之气将要发动时，又受到突然袭来的寒气侵袭，所以在夏天转化为热病。既然已经转化之后，就不能再说是寒病了。凡是热病的发生起因、致病因素、所感邪气、出现的症状脉象及治疗方法，都与温病相同。（《热病伤寒第四十九》）
The *Classic of Internal Medicine* (*Huangdi Neijing*) states: "If one is injured by cold in winter, one will inevitably suffer from warm disease in spring." This refers to the situation where an infection with seasonal pathogenic factors does not manifest immediately but lies latent between the skin and interstices (subcutaneous tissue), only erupting after a period of time when triggered. Furthermore, this distinguishes among three conditions: immediate-onset Shanghan (Cold Damage), Shangfeng (Wind Strike), and Fuwen Bing (Latent Warm-Heat Disease). In Shanghan, symptoms include fever, absence of sweating, and aversion to cold; in Shangfeng, symptoms include fever, presence of sweating, and aversion to wind. Both involve pathogens entering from the exterior, resulting in an exterior syndrome while the interior remains harmonious, characterized by a cold sensation in the nose but no thirst in the mouth. In contrast, warm-heat diseases involve pathogens emerging from the interior, leading to fever with either sweating or no sweating, a lack of cold sensation in the nose, and thirst. The pathogens of Shanghan and Shangfeng enter along the meridians and gradually deepen; therefore, treatment must strictly differentiate between the Three Yang and Three Yin meridians, clearly distinguishing between exterior/interior, cold/heat, and deficiency/excess patterns before applying therapy, allowing for not the slightest error. For warm-heat pathogens emerging from the interior, the treatment merely involves dispersing or purging heat in the exterior, middle, and interior levels; what difficulty could there be? (From "Supplementary Discussion on Warm-Heat Diseases")
(1) Warm disease is the transformation of cold latent during winter. During winter, Yang Qi is latent within, and upon contracting cold, the disease does not manifest immediately but hides latent in the skin and muscles. When the warming Qi of spring is about to arise, if exposed to sudden cold, it transforms into warm disease in spring. Once transformed, it can no longer be referred to as a cold disease. Additionally, if Shanghan persists beyond its normal course after sweating or purgative treatments, it is also termed warm disease. In such cases, diaphoresis (sweating-inducing therapy) is contraindicated because, having passed the initial stage, the pathogen is no longer in the exterior; furthermore, since sweating or purgation has already been applied, the pathogen is certainly not in the exterior. The *Classic* states: "Those who do not experience aversion to cold but feel thirsty are suffering from warm disease." Lack of aversion to cold indicates the pathogen did not come from outside; thirst clearly indicates that heat originates from within and reaches outward, thereby proving the absence of exterior signs. The pulse of warm disease moves through the various meridians; without knowing which meridian is affected, one should diagnose and treat according to the location of the involved meridian. For example, in Taiyang disease (Taiyang Meridian Disease), presenting with headache and fever, if it persists beyond the course after sweating and the pulse at Cun, Guan, and Chi positions is floating in both hands, it is Taiyang warm disease. If fever and eye pain persist beyond the course after sweating/purgation and the pulse is wiry and long, it is Yangming warm disease. If hypochondriac pain persists and the pulse is wiry, it is Shaoyang warm disease. If abdominal fullness and dry throat persist and the pulse is deep, it is Taiyin warm disease. If dry tongue and mouth persist and the pulse is slightly deep, it is Shaoyin warm disease. If irritability, fullness, and contraction of the genitals persist and the pulse is slightly slow, it is Jueyin warm disease. The key is to treat according to the specific meridian. Most warm diseases originate in the Three Yang meridians, while few originate in the Three Yin meridians. If it originates in the Yin meridians, there must be a cause, such as internal injury from diet or prior damage to the Kidney meridian due to sexual excess. (From "Warm Disease and Cold Damage, Chapter 48")
(2) Heat disease is also the transformation of cold latent during winter. During winter, Yang Qi is latent within, and upon contracting cold, the disease does not manifest immediately but hides latent in the skin and muscles. When the summer heat Qi is about to arise, if exposed to sudden cold, it transforms into heat disease in summer. Once transformed, it can no longer be referred to as a cold disease. The etiology, pathogenesis, symptomatic manifestations, pulse characteristics, and treatment methods of heat disease are identical to those of warm disease. (From "Heat Disease and Cold Damage, Chapter 49")