赵嗣真曰∶按仲景论，谓冬月冒寒，伏藏于肌肤，而未即病，因春温气所变，则为热。夫变者，改易之义也。至此，
则伏寒各随春夏之气，改变为温为热，既变之后，不得复言其为寒也。所以仲景云温病不恶寒者，其理可见矣。《活人
书》其于温病曰∶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，能制其阳热尔。外有寒邪能折阳气者，乃是时行
寒疫，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。是知时行寒疫，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。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。（《伤寒琐言·伤寒变温热病
论》）
（一）至春分节后，天令温暖，有人壮热为病者。乃温病也。《经》云∶冬伤于寒，发为温病。又云∶太阳病发热
而渴，不恶寒者为温病。言冬时伏气，随时温热发出，但所发之因不同，有感非时暴寒而发者；有饥饱劳役而发者；有
房室作力而发者。所感之客邪既殊，发出之经络亦异，所谓温病之脉，行在诸经，不知何经之动也，当随其经证而治之。
凡温病之发，必大渴烦扰，胁满口苦，不恶寒反恶热，脉气口反盛于人迎，明系伏邪自内达表，必先少阳经始。（《温病》）
（二）大抵治温病、热病，无正发汗之理。盖其邪自内达外，无表证明矣。若果证显非时暴寒，恶寒头痛，而脉浮
紧者，亦不可纯用表药。（《温病》）
（三）大抵温病热病，皆是热郁之气，故多发于三阳。若发于三阴者，必难治。其脉若沉细，或微弱，或虚大无力，
为脉不应病，必死。然发于三阴者，必有所因，或因冷食伤脾，或因欲事伤肾，皆正气先伤，热毒乘虚而发，设用甘温
调补，宁不助邪转炽。若行苦寒峻攻，真元立致消亡，虽长沙、河间复起，恐难为力矣。（《热病》）
Zhao Sizhen stated: Examining Zhang Zhongjing's treatise, it is said that in winter, one contracts cold pathogens which lie dormant in the skin and muscles without causing immediate illness. When spring warmth arrives, this latent condition transforms into heat. The term "transform" (bian) implies alteration or change. At this stage, the latent cold follows the qi of spring and summer, transforming into warm diseases or heat diseases. Once transformed, it can no longer be referred to as cold. Thus, Zhang Zhongjing's statement that warm diseases do not present with aversion to cold becomes understandable.
The *Huoren Shu* (Book of Living People), regarding warm diseases, states: "When yang-heat is not yet abundant, it is constrained by cold." How could it be said that if latent cold has already transformed into warmth, cold could still constrain its yang-heat? Furthermore, regarding heat diseases, it states: "When yang-heat is already abundant, cold cannot constrain it," implying it should no longer be described as cold. This is because during spring and summer, yang-heat has already transformed, and the latent cold no longer possesses the nature of cold to constrain yang-heat.
However, there are cases where external cold pathogens damage yang-qi; these are termed seasonal cold epidemics (shixing hanyi). This corresponds to Zhang Zhongjing's description: "After the Spring Equinox and before the Autumn Equinox, sudden cold weather constitutes a seasonal cold epidemic." In March and April, when yang-qi is still weak, if damaged by cold, the resulting fever is mild. In May and June, when yang-qi is abundant, if damaged by cold, the resulting fever is severe. In July and August, when yang-qi is declining, if damaged by cold, the resulting fever is also slight. From this, we know that for seasonal cold epidemics and warm/heat diseases, the discussion on the abundance or decline of yang-qi and the months involved is consistent. However, the cold of sudden weather differs from the cold of latent pathogens that have already transformed; they are contradictory. If names are incorrect, speech does not flow logically. Zhang Zhongjing further stated: "This disease resembles warm diseases and summerheat diseases, but the treatment differs." The key lies in distinguishing the sources among cold, heat, and warmth; only then will the distinction between using cold or hot medications be clear. (From *Shanghan Suoyan · Lun Shanghan Bian Wenre Bing*)
(1) After the Spring Equinox, when the weather turns warm, individuals suffering from high fever are afflicted with warm diseases. The *Neijing* (Classic of Internal Medicine) states: "Cold contracted in winter develops into warm diseases." It also states: "Taiyang disease (disease syndrome caused by pathogenic invasion of the Taiyang channel) presenting with fever, thirst, and aversion to cold is classified as a warm disease." This refers to latent pathogens from winter emerging with the seasonal warmth. However, the causes of emergence differ: some arise from contracting sudden cold out of season; some from irregular diet and overwork; others from sexual exertion. Since the exogenous pathogens differ, the channels through which they emerge also vary. As stated, the pulse of warm diseases circulates through various channels, and it is unknown which channel is affected; therefore, treatment should follow the specific channel symptoms. Generally, when warm diseases manifest, there is intense thirst, restlessness, hypochondriac fullness, bitter taste in the mouth, aversion to heat rather than cold, and the pulse at the Cun Kou position is stronger than at the Ren Ying position. This clearly indicates latent pathogens moving from interior to exterior, necessarily starting from the Shaoyang channel. (From *Wenbing*)
(2) Generally, there is no rationale for inducing sweating as a primary method in treating warm diseases and heat diseases. This is because the pathogens move from interior to exterior, indicating the absence of exterior syndromes. Even if symptoms clearly indicate sudden cold out of season, with aversion to cold, headache, and a floating-tight pulse, one should not rely solely on exterior-releasing medications. (From *Wenbing*)
(3) Warm diseases and heat diseases are essentially due to stagnant heat qi, so they mostly occur in the Three Yang channels. If they occur in the Three Yin channels, they are difficult to treat. If the pulse is deep-thin, faint, or empty-large and powerless, it represents a mismatch between pulse and disease, indicating certain death. However, occurrences in the Three Yin channels must have underlying causes, such as spleen injury from cold food or kidney injury from sexual activity. In these cases, healthy qi is first damaged, allowing heat toxins to erupt upon deficiency. If sweet-warm tonifying methods are used, it would only exacerbate the pathogen. If bitter-cold purgative methods are employed, vital essence (Zhenyuan) will rapidly perish. Even if Zhang Zhongjing or Liu Wansu were to return, they might find it difficult to save the patient. (From *Rebing*)