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Ancient medical texts mention diseases that manifest upon the arrival of solar terms, a phenomenon recorded only in the "Shi Zhu Hou" (Posture and Etiology of Corpse-Infestation) chapter of *Zhu Bing Yuan Hou Lun* (Source Book of All Categories of Diseases), yet it is frequently observed in clinical practice. Some diseases manifest on the day of the solar term transition, while others appear several days before or after; these are not necessarily all cases of Shi Zhu (Corpse-Infestation). In essence, if the root of the disease is not eradicated, it will recur after remission. Why must it manifest upon the solar term? Examining phenomena that respond to solar terms, none is more evident than the Eight Winds (Winds from the eight directions). Wind is regarded as the qi transformation of Central Earth (based on Zheng Xuan's commentary on the *Book of Documents*, detailed in the preceding section "On Wind-Dampness"). Earth governs "Trustworthiness" (Xin) among the Five Virtues; thus, it arrives at its appointed time without error. Since the classics state that "Wind is the leader of a hundred diseases," it can be deduced that diseases manifesting upon solar terms are necessarily related to Wind pathogen.

When Wind pathogen remains in the meridians, it manifests with each external contraction. Furthermore, five days constitute one pentad (Hou), three pentads constitute one Qi (solar term period), and one Qi corresponds to the general law of the moon's waxing and waning. Only the human meridians undergo prosperity and decline following the moon's phases. Therefore, only when Wind pathogen has resided in the meridians for a long time will it manifest upon the solar term; if the pathology is not located within the meridians, even if it involves chronic Wind, it will not manifest specifically upon the solar term. Consequently, this pattern of manifestation upon solar terms is most common in conditions of Wind deficiency and consumptive fever (Xu Lao).

The previous discussion regarding Yang pulse indicating prior pathogen invasion and Yin pulse indicating subsequent invasion originates from Dai Shuwei. In his analysis of Wet-Warmth (Shi Wen) pulse patterns, where the Yang pulse is soggy and weak while the Yin pulse is small and rapid, he posited that Warmth pathogen was invaded first, followed by Dampness. By analogy, the principle holds true, and this also indicates that the pulse of Warmth disease presents as soggy and weak. The intent of the classic text is that when pathogens invade the human body and involve both exterior and interior simultaneously, the Yin and Yang pulses should be consistent, as seen in Warm Malaria (Wen Nue). However, if one pathogen is invaded first and another subsequently, the pathogen initially present in the Yin aspect must retreat and merge into the Yang aspect, allowing the later-invading pathogen, uniquely present in the Yin, to penetrate the Yang. This logic applies to the pulse methods of Wind-Warmth, Warm Toxin, and Warm Epidemic. The reason the later pathogen cannot sink into the Yang aspect is that the Yang aspect already harbors residual pathogens; the reason the earlier pathogen cannot transcend into the Yin aspect is that the Yin aspect already contains new pathogens. The new pathogen desires to descend but cannot; the residual pathogen desires to ascend but cannot. If sweating therapy is applied because descent is impossible, the residual pathogen will ascend along with the new pathogen, exacerbating the illness. If purgation therapy is applied because ascent is impossible, the new pathogen will deepen into the interior along with the residual pathogen, complicating the pathology. Both of these two transformations are difficult to treat. One must clearly understand the pulse methods of Warm-Heat diseases to diagnose Warmth diseases; similarly, one must master the diagnostic methods for Warmth diseases to treat them effectively. Therefore, the general principle for treating Warmth diseases prohibits therapies that rely solely on sweating or purging, advocating instead for combined sweating and purging therapies. Wei Rui Tang (Rehmanniae Radix Decoction) is a formula that employs both sweating and purging. By extrapolating from Wei Rui Tang to other formulas, one can grasp the majority of the underlying principles.