Library

Whenever treating *Shanghan* (Cold Damage) and *Wenyi* (Plague Epidemic), physicians place the greatest emphasis on the initial onset of the disease. Regarding "Chaofu" (recurrence of the epidemic after apparent recovery), it is often considered that few die, leading practitioners to view it as a minor condition and treat it with negligence. The reasoning is that in cases of recurrence, the meridians and zang-fu organs have already been traversed by the pathogenic factors during the previous infection; thus, this time the pathogen merely travels a familiar route, making it easier to expel. Ancient texts indeed contain such arguments, but these only describe the general rule. However, during periods of rampant epidemic, this is not the case. At such times, the epidemic qi accumulates densely. Even without causes related to diet or overexertion, there are recurrences due to secondary contraction of pestilential qi. Furthermore, residual pathogens from the previous episode may linger, undergo further fermentation and spread, and suddenly recur. This occurs because the external pathogenic factors adhere firmly to the patient's qi and blood, causing blockage, stagnation, and chaotic entanglement. Consequently, patients may suffer fatal outcomes even after three or four recurrences. One must never disregard the condition simply because it is a recurrence.

*Shanghan* is caused by cold injury, which has a specific etiology; therefore, the primary treatment for the initial contraction is always diaphoresis (sweating to release the exterior). If *Wenyi* occurs concurrently and is triggered by cold, it cannot be treated using methods for *Shanghan*. Not only should *Mahuang Tang* (Ephedra Decoction) and *Guizhi Tang* (Cinnamon Twig Decoction) be avoided, but also *Qianghuo Tang* (Notopterygium Decoction) and *Shishen Tang* (Ten Deities Decoction) are not appropriate remedies. This illustrates why "reading only *Shanghan* books is insufficient to treat *Wenyi*." Moreover, the variety of complex symptoms presented by *Wenyi* is nearly equal to that of *Shanghan*. In Wu Keyi’s *Wenyi Lun* (Treatise on Pestilential Diseases), there are only a few entries regarding macules, yellow sweat, and mania. However, the formulas and discussions in *Shanghan Lun* (Treatise on Cold Damage Disorders) concerning various sweating patterns, pains, bleeding disorders, delirium, mania, thirst, irritability, palpitations, convulsions, mutism, head shaking, and abnormalities of urination and defecation can be extensively adapted and utilized in the treatment of *Wenyi*. Nevertheless, careful deliberation is required to ensure perfection; this depends entirely on the physician's scholarly attainment and insight, which cannot be fully conveyed through mere words. This explains why "not reading *Shanghan* books makes one insufficient to treat *Wenyi*."

Books on *Shanghan* generally intermingle yin and yang syndromes. They abruptly mention yang syndromes treated with *Xiaoshi* (Mirabilite) and *Dahuang* (Rhubarb), then abruptly mention yin syndromes treated with *Guizhi* (Cinnamon Twig) and *Fuzi* (Aconite Root). Examining the author's intent, although they are discussed together, the internal analysis remains clear: if a yang syndrome presents thus, a yin syndrome presents otherwise. Readers who fail to grasp this nuance tend to confuse yin and yang syndromes into a single entity. Thus, some claim that a single patient's illness fluctuates between yin and yang; others assert that disease in yang meridians constitutes a yang syndrome, while transmission to yin meridians constitutes a yin syndrome; still others argue that yin and yang are mixed and indistinguishable. These fragmented views are numerous and varied. Even excluding these, many consider yin syndromes common in clinical practice, accounting for half of all cases. Consequently, when diagnosing, physicians often struggle internally with distinguishing yin from yang, lacking definitive judgment. No wonder medication errors occur, leading to fatal mistakes. To eliminate this flaw, it is best to study them separately: first master the transmitted yang syndromes, and temporarily postpone studying the direct-entry yin syndromes. Once yang syndromes are understood, learning yin syndromes becomes easy. Why? Yang syndromes are complex with diverse manifestations, whereas yin syndromes involve no transmission, have fewer treatment methods, and are easier to learn and treat. They should be categorized under "Complex Syndromes," grouped with summerheat, dampness, cholera, and other similar diseases, thereby avoiding the error of misdiagnosing yin and yang.