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Zhou Yuzai said: Zhang Zhongjing followed the principles of heat diseases in the *Neijing* (Inner Canon), expounded on the theory of latent pathogens, and specifically discussed summer-heat diseases and the treatment with Baihu Tang (White Tiger Decoction). This can be considered extremely precise. However, he further presented the disease of "Zhong Yue" (Heatstroke) in the *Jingui Yaolue* (Essential Prescriptions from the Golden Cabinet), stating: "Taiyang heat-stroke is called Zhong Yue." He likely feared that people would mistakenly identify heatstroke as ordinary febrile diseases; thus, he emphasized that the pathogen enters from the exterior, while the heat erupts from internal latent factors, implying two distinct pathways.

Nevertheless, Summer-heat (Shu) is the ruling qi of fire in summer. It injures human Qi (Vital Energy), leading to a deficient pulse, feverish body, extreme thirst, dry teeth, sweating, and panting. This presentation is no different from the eruption of latent diseases. Both are treated with Baihu Tang (White Tiger Decoction), primarily using sweet-cold herbs to clear heat, bitter-cold herbs to eliminate fire, and sweet-warm herbs to tonify the Middle Jiao (Spleen and Stomach). The reason for tonifying the Middle is that Summer-heat easily damages Qi, necessitating supplementation. However, if Yin fluids are severely depleted, Ginseng must be added. This approach has nothing to do with using acrid-dispersing or warm-dispersing agents.

Some might argue: Since latent diseases originate internally, Baihu Tang is appropriate. But since Zhong Yue enters from the exterior into the interior, why suddenly use interior-resolving medications? They might claim that because the formula slightly includes wind-dispelling herbs to scatter the exterior, it seems acceptable. I believe the eternal misunderstanding lies precisely here. Although Summer-heat in summer and Cold in winter are opposing forces, their dynamics regarding the exterior and interior are vastly different.

In winter, the interstices (Cou Li) are tight. Even if one is affected due to defensive Qi deficiency, the invasion must be gradual. Why? Because winter is characterized by outer Yin and inner Yang. In summer, however, the human body has Yang Qi on the exterior and Yin Qi on the interior. With the external barrier relaxed, Summer-heat can enter directly. Therefore, when contracting Wind-Cold, the pathogenic factor often manifests as "excess" (repletion); excess indicates the pathogen. When contracting Summer-heat, the healthy Qi often manifests as "deficiency"; deficiency indicates the healthy Qi.

Currently, some consider Xiangru (Elsholtzia Herb) an indispensable herb for treating Summer-heat injury. They fail to realize that it is suitable only for cases where cooling off and drinking cold substances suppress Yang Qi, or for those resulting in cholera-like symptoms. For cases involving strenuous labor and severe internal injury, the method of clearing Summer-heat and tonifying Qi is much closer to the truth. Using Xiangru in such cases would doubly weaken an already deficient state. Moreover, how could one add acrid-warm exterior-dispersing herbs to the mix?

Mr. Zhang Fengkui of the Ministry of Works edited various books, specifically aiming to correct these errors. My teacher, Master Lin from Beihai, clarified the major principles and collected famous medical cases to serve as references for posterity. Is this not a task one can undertake with competence and joy? As a junior scholar, I have once again offered this clarification, hoping to establish Baihu Tang (White Tiger Decoction) as the primary treatment, assisted by Qingshu Yiqi Tang (Clear Summer-heat and Tonify Qi Decoction), while always adjusting according to specific symptoms. Formulas such as Tianshui San (Heavenly Water Powder) and Ganlu Yin (Sweet Dew Drink) may also be cited. Regarding the arguments of Jie'an, I see no merit in them. For any doubts, please observe the contraindications of sweating, purging, and moxibustion/needling warmth, which originate from the Sage Zhang Zhongjing. Conditions such as vomiting and diarrhea due to food retention, distension and fullness due to Qi stagnation, cold extremities due to Cold invasion, and aversion to cold due to Wind co-invasion, all require diagnosis through pulse analysis without confusion. Only then will one understand that the Sage's discussions represent the constant norms, while adaptations to specific encounters represent variable applications. Understanding the constants allows one to handle standard conditions well; mastering the variables ensures proficiency in applying flexible strategies. Precedent cases from former sages exist for reference. Only those who thoroughly comprehend the *Shanghan Lun* (Treatise on Cold Damage) can divine and illuminate its profound meanings.