伏温由阴而出于阳，于病机为顺。若病发于阴，而即溃于阴，不达于阳，此病机为逆。若是乎阴阳两层，
界限分明，安有淆乱者哉。凡病之阴阳淆乱者，其故有二∶一则由乎正虚，如阳虚者阴必凑之，则阴病可淆于
阳矣∶阴虚者阳必扰之，则阳病可淆于阴矣。一则由乎药误，如病在阴而误投阳药，则阳气
为药所伤，而阴病淆于阳矣；病在阳而误投阴药，则阴气为药所伤，而阳病淆于阴矣。至其见证错杂，有即由
于阴阳淆乱而杂者，有由他邪之兼挟而杂者。看此等证∶全要天分聪明，识见老到，方有把握。盖此等证，变
化最多，无一定路迳可循。临病者，须将正气邪气，表病里病，新邪旧邪，孰本孰标，孰轻孰重，孰缓孰急，
一一衡量得宜，方可施治。有当先顾本元，苟得正气一旺，而邪自解散者；有当急祛外邪，必得邪气速退，而
正乃不伤者；有症虽错出，而发于一原，只须专治其本，而各症自退，所谓缓则治其本者；有证虽在标，而病
机甚急，必须先治标病（如小便不利之类），而本病从缓，所谓急则治其标者；有病势蔓延，欲治其根，而正
气不支，只可先披其枝叶，而用渐衰渐胜之法者∶有病情纠结，必除其根，而各证自退，不得不攻其坚垒，而
用擒贼擒王之计者；以上所谓错杂，犹不过表里虚实，其用药尚可一线相承。此外更有寒热错杂，如阴虚而挟
寒饮，阳虚而挟肝火，治此则碍彼，治彼则碍此者，其用药更难措手。此中奥妙，有知之而不能言，言之而不
能尽者。总宜于轻重缓急，权之极精，方可论治。至选药宜彼此照顾，尤必有手挥五弦、目送飞鸿之妙，乃为
得法。否则失之毫厘，谬以千里，其不误人性命者鲜矣。
伏气温病由阴分透发于阳分，在病机演变上属于顺证。如果病邪发自阴分，却随即深陷于阴分，不能透达于阳分，这属于病机逆乱。既然这样，阴阳两层界限分明，怎么会有混淆错乱的情况呢？凡是出现阴阳混淆错乱的病症，原因主要有两个：一是由于正气虚弱，例如阳气虚衰时阴寒之邪必然凑集，导致阴病混淆于阳；阴液亏虚时阳热之邪必然扰动，导致阳病混淆于阴。二是由于用药错误，例如病在阴分却误用治阳分的药物，导致阳气被药物所伤，从而阴病混淆于阳；病在阳分却误用治阴分的药物，导致阴气被药物所伤，从而阳病混淆于阴。至于临床表现错综复杂，有的是直接因为阴阳混淆而夹杂出现的，有的是因为兼夹其他病邪而夹杂出现的。诊治这类证候，全凭医生的天赋聪慧和见识老练，才能把握得当。因为这类证候变化最多，没有固定的路径可循。临证时，必须将正气与邪气、表证与里证、新感之邪与旧有之邪、谁是根本谁是标象、谁轻谁重、谁缓谁急，一一衡量妥当，才可以实施治疗。有的应当先顾护本元，只要正气旺盛，邪气自然解散；有的应当紧急祛除外邪，必须使邪气迅速退去，正气才不受损伤；有的症状虽然交错出现，但发源于同一根本，只需专门治疗其根本，各症状自然消退，这就是所谓的“缓则治其本”；有的证候虽然表现为标象，但病机非常紧急，必须先治疗标病（如小便不利之类），而本病暂缓处理，这就是所谓的“急则治其标”；有的病势蔓延，想要根治，但正气不支，只可以先清除其枝叶症状，采用逐渐衰退病邪、逐渐增强正气的治疗方法；有的病情纠结，必须去除病根，各证候自然消退，不得不攻取坚固的病邪堡垒，采用擒贼先擒王的策略；以上所说的错杂，还不过是表里虚实的问题，用药还可以一脉相承。此外更有寒热错杂的情况，如阴虚而兼挟寒饮，阳虚而兼挟肝火，治疗这方面会妨碍那方面，治疗那方面会妨碍这方面，用药更加难以着手。其中的奥妙，有知道却无法说清，说了也无法尽述的。总之应当在轻重缓急之间权衡得极其精准，才可以讨论治疗。至于选药应当彼此照顾，尤其必须具备手挥五弦、目送飞鸿般的巧妙境界，才算得法。否则失之毫厘，谬以千里，不误人性命的情况就很少了。
Fuwen (latent warm pathogen) emerging from the Yin level to the Yang level is considered a favorable progression in disease mechanism. If the pathogen originates in the Yin but remains entrenched in the Yin without penetrating to the Yang, this constitutes an unfavorable (reverse) progression. Given that the boundaries between the Yin and Yang levels are distinct, how can confusion arise? There are two main causes for such Yin-Yang confusion: first, due to deficiency of healthy Qi (Zhengqi). For instance, when Yang Qi is deficient, Yin pathogens inevitably encroach, causing Yin pathology to confuse with Yang; conversely, when Yin fluids are deficient, Yang pathogens inevitably disturb, causing Yang pathology to confuse with Yin. Second, due to therapeutic errors. If the pathology resides in the Yin but Yang-tonifying or Yang-releasing herbs are mistakenly administered, the Yang Qi is damaged by the medication, leading to Yin pathology confusing with Yang; if the pathology resides in the Yang but Yin-nourishing or Yin-cooling herbs are mistakenly administered, the Yin Qi is damaged, leading to Yang pathology confusing with Yin. Regarding the complex clinical manifestations, some arise directly from Yin-Yang confusion, while others result from the concurrent presence of other pathogens. Diagnosing such cases relies entirely on the physician's innate intelligence and mature diagnostic insight to ensure accuracy. These cases exhibit the most variations, with no fixed pathways to follow. The clinician must carefully weigh the relationship between healthy Qi and pathogenic factors, exterior and interior syndromes, new versus old pathogens, root versus branch, severity, and urgency. Only after proper assessment can treatment be initiated. In some cases, it is necessary to first protect the fundamental Yuan Qi; once healthy Qi is robust, pathogens will dissipate naturally. In other cases, it is urgent to expel external pathogens; only by rapidly eliminating pathogens can healthy Qi remain unharmed. Some symptoms appear mixed but originate from a single root; treating the root specifically allows all symptoms to recede, which is known as "treating the root in slow/chronic conditions." Some presentations manifest as branch symptoms, yet the disease mechanism is critical; the branch must be treated first (e.g., difficulty in urination), while the root is addressed later, known as "treating the branch in acute/emergency conditions." In cases where the disease spreads widely but healthy Qi cannot support aggressive radical treatment, one may first address the superficial branches using methods that gradually reduce pathogens while gradually strengthening healthy Qi. In situations where the condition is tangled and requires removing the root for all symptoms to resolve, one must attack the solid pathological fortress, employing a strategy akin to "capturing the king to capture the rebels." The aforementioned complexities mainly involve exterior-interior and deficiency-excess dynamics, allowing for consistent therapeutic approaches. However, there are further complexities involving mixed cold and heat, such as Yin deficiency accompanied by cold-fluid retention, or Yang deficiency accompanied by Liver Fire. Treating one aspect hinders the other, making medication difficult to administer. The subtleties involved are often known but indescribable, or describable but not fully comprehensible. Ultimately, precise weighing of severity and urgency is essential before discussing treatment. Herb selection must consider mutual interactions, requiring the skillful mastery likened to "playing the lute while watching the flying geese" (handling multiple tasks with grace and precision). Otherwise, a slight error leads to a massive deviation, and survival is rare.