一阴一阳之谓道，天地万物，莫之能外。阳主发舒，阴主收敛；阳主生长，阴主肃杀。人受二气之中以生，阴
阳调和，康强寿考。次则阳气胜者，虽不无少偏，犹足自立。至阴气一盛，则阳气渐消，疾病夭折，不可究诘
矣。寒者阴气也，即肃杀之气也。寒气中人，为祸最烈。仲景欲利济万世，着伤寒、中寒为二论。《伤寒论》十
卷，炳如日星，后世奉为科律。《卒病论》六卷，自晋以来，久已散失，无可稽考。然其分为二门之意，则可揣
而知也。伤寒者，传变之症，多由发热而起，经所谓凡热病者皆伤寒之类也。人之阳气，未至大衰，虽感冒
风寒，一时阳为阴掩，究竟真阳尚在，则阳回气复，而病变亦旋瘳。自有《伤寒论》以来，后之注释者，若程
氏、柯氏、吴氏，代有发明。至喻氏《尚论篇》，更畅其说。学人融会贯通，可以泛应各当，故此编于伤寒门中，
概不置喙，非阙也，实亦无庸更赞一词也。今于中寒门，分列数条，盖恐人不知传经直中之分，仍以治伤
寒之法治中寒，则大不可耳。伤寒者，寒从外来；中寒者，寒从内发。伤寒多发热之候，中寒则但有厥冷，
而无发热之候，此必其人之真阳先亏，坎中之火渐为水淹；又必有澄寒痼冷，伏于脏腑，一遇寒气，积病猝
发，极为危险。故非气雄力浓之温剂，不能斩关夺门，以回真阳于俄顷，非如伤寒传经之症，可以按部就
班也。其见症列后。
The interplay of one Yin and one Yang is termed the "Dao" (Way); all things in heaven and earth cannot exist outside of it. Yang governs expansion and comfort, while Yin governs contraction and storage; Yang governs growth, and Yin governs desiccation and killing. Humans are born receiving the influence of these two Qi (vital energies). When Yin and Yang are harmonious, one enjoys health, robustness, and longevity. Next, those whose Yang Qi prevails may have slight imbalances but are still capable of sustaining themselves. However, when Yin Qi becomes excessive, Yang Qi gradually diminishes, leading to disease and premature death, with consequences that are incalculable. Cold is a form of Yin Qi, specifically the Qi of desiccation and killing. When Cold Qi invades the human body, its harmful effects are the most severe. Zhang Zhongjing, wishing to benefit ten thousand generations, composed two treatises: *Shanghan Lun* (Treatise on Cold Damage) and *Zhonghan Lun* (Treatise on Mid-Cold). The *Shanghan Lun*, consisting of ten volumes, shines as brightly as the sun and stars, and has been revered by later generations as the standard for clinical practice. The *Zubing Lun* (Treatise on Sudden Diseases), consisting of six volumes, has been lost since the Jin Dynasty and cannot be verified. Nevertheless, the intention behind dividing them into two categories can be inferred. Shanghan refers to syndromes characterized by transmission and transformation, often starting with fever. As the classic states, "All febrile diseases belong to the category of cold damage." If a person's Yang Qi has not yet severely declined, even if they contract wind-cold, causing their Yang to be temporarily obscured by Yin pathogenic factors, their True Yang remains intact. Consequently, once Yang returns and Qi recovers, the pathological changes will quickly resolve. Since the publication of the *Shanghan Lun*, commentators such as Cheng Shizuo, Ke Qin, and Wu Qian have successively made new discoveries. Yu Jiayan's *Shanglun Pian* further elucidated these theories. Students who can integrate and master these concepts can respond appropriately to various situations. Therefore, this compilation does not intervene in the Shanghan section, not due to omission, but because there is no need to add further words. Now, in the Zhonghan section, several items are listed separately, likely out of fear that people do not understand the distinction between "transmission through meridians" (Chuan Jing) and "direct invasion" (Zhi Zhong). If one were to use the methods for treating Shanghan to treat Zhonghan, it would be a grave error. Shanghan involves cold entering from the exterior; Zhonghan involves cold arising from within. Shanghan typically presents with fever, whereas Zhonghan presents only with cold extremities (Jue Leng) without fever. This indicates that the patient's True Yang was previously deficient, and the Fire of the Kidney (Kan Zhong) was gradually submerged by water/cold. Furthermore, chronic cold and entrenched chill must have been lurking within the Zang-Fu organs. Upon encountering cold, these accumulated pathogens suddenly erupt, posing extreme danger. Therefore, only potent warming formulas with strong medicinal force can break through barriers and restore True Yang in an instant, unlike Shanghan syndromes which involve transmission and can be treated step-by-step. The presenting symptoms are listed below.