Zhang Zhongjing said: Taiyang heat-stroke (Taiyang zhong re) is this condition. The patient sweats, fears cold, has a fever, and feels thirsty. *Jin Gui Yao Lue* states: It is primarily treated with Baihu Jia Renshen Tang (White Tiger Decoction plus Ginseng). Guo Yong stated: There are also cases of fearing wind, which is due to excessive sweating.

He further said: In Taiyang heat-stroke (Zhong Yue), the body feels hot and heavy with pain, and the pulse is faint and weak. This is caused by injuring cold water in summer, leading to water qi circulating within the skin. *Jin Gui Yao Lue* states: It is primarily treated with Goudi San (Melon Sepal Powder).

He further said: In Taiyang heat-stroke (Zhong Yue), there is fever and aversion to cold, heaviness of the body with pain, and the pulse is string-taut, fine, hollow, and slow. Urination is difficult or scanty; the person shivers as if sprinkled with cold water, and the hair stands on end. The hands and feet are cold. Upon slight exertion, the body becomes hot. The mouth opens to breathe, and the front teeth appear dry. If sweat-inducing methods are used, the aversion to cold will worsen. If warm needle therapy is applied, the fever will intensify. If purgatives are used repeatedly, strangury (Lin syndrome) will worsen. Pang Anchang stated: Da Xiao Ju Pi Tang (Large and Small Tangerine Peel Decoctions) should be used. Da Ju Pi Tang treats "moving Qi" located below, where sweating is contraindicated. Xiao Ju Pi Tang primarily treats cold hands and feet with vomiting and hiccups; it consists of only two herbs: Sheng Jiang (Fresh Ginger Rhizome) and Ju Pi (Tangerine Peel).

Question: How to differentiate between heat-stroke (Zhong Shu), heat-stroke from summer-heat (Zhong Yue), and febrile disease (Re Bing)? Guo Yong answered: Febrile disease occurs when one is injured by cold in winter, which manifests later due to summer-heat qi. Heat-stroke (Zhong Shu) occurs when one is not injured by cold in winter but is directly injured by summer-heat in summer. Heat-stroke (Zhong Shu) is essentially Zhong Yue. Both involve pathogenic invasion of the Taiyang channel. Therefore, febrile disease truly belongs to the category of Cold Damage (Shang Han), while heat-stroke resembles Cold Damage. *Huo Ren Shu* states: In summer, if there is fever, aversion to cold, headache, heavy pain in the body and joints, and a surging pulse, it is a febrile disease. In summer, if there is spontaneous sweating, aversion to cold, fever, thirst, and a faint pulse, it is heat-stroke. Generally, the external symptoms of heat-stroke and febrile disease are similar, but they are distinguished by whether the pulse is surging (excess) or faint (deficiency). *Jia Yi Jing* states: A surging pulse with cold body indicates injury by cold (Shang Han); a faint pulse with hot body indicates injury by summer-heat (Shang Shu). This is because cold injures the form/body but not the Qi, resulting in a surging pulse; heat injures the Qi but not the form, resulting in a faint pulse. Cold damage causes heavy pain in limbs and joints, with a surging pulse that is forceful upon pressure; this is deep cold contracted in winter manifesting in summer. Heat-stroke presents with coldness in the back, greasy facial complexion, slightly cold hands and feet, irritability, thirst, and dry mouth, with a feeling of fatigue, but without heavy pain in the limbs. The pulse is faint and weak upon pressure. It is treated with Baihu Tang (White Tiger Decoction). For cases with cold extremities and aversion to cold, Ju Pi Tang (Tangerine Peel Decoction) is used. For headache, aversion to cold, mental restlessness, and discomfort in the epigastrium, Wu Ling San (Five-Ingredient Powder with Poria) is most effective.

Question: Why does heat-stroke cause shivering (Sa Sa Ran Mao Song) and aversion to cold? Zhu Shi stated: The classics say: When the eight winds of the four seasons invade humans, there is differentiation between cold and heat. Cold causes skin tightening and closure of interstices (Cou Li); heat causes skin relaxation and opening of interstices. When open, one feels chilly (Sa Ran Han); when closed, one feels hot and stifled. Modern practitioners often fail to distinguish between heat-injury and summer-heat-injury, treating them as febrile diseases and using warm-hot medicines. This inevitably leads to jaundice and macular eruptions, or even blood stasis accumulation. This must be strictly avoided.

Question: Febrile disease, summer-heat disease, and Zhong Yue have different names, yet various schools do not distinguish them. What is your view? Guo Yong answered: Febrile disease can also be called summer-heat; Zhong Yue can also be called summer-heat. Thus, sometimes "heat" is mentioned, and sometimes "summer-heat." Initially, there are two conditions involving heat: febrile disease and Zhong Yue. Because they are interconnected, they can all be termed summer-heat, hence the three names, making them difficult to distinguish. *Su Wen* states: Febrile diseases are all of the category of Cold Damage. This refers to the aspect of "heat."

It further states: Diseases occurring before the Summer Solstice are called Warm Disease (Wen Bing); those occurring after the Summer Solstice are called Summer-Heat Disease (Shu Bing). This refers to the aspect of "summer-heat." Essentially, these two are the same. Zhang Zhongjing and Wang Shuhe stated: If Zhong Yue manifests immediately, it is named Cold Damage (Shang Han). If it does not manifest immediately, it transforms into Warm Disease in spring and Summer-Heat Disease in summer.

It further states: Laborers are prone to warm-heat diseases in spring and summer. This single condition is referred to as either summer-heat or heat. Therefore, Chao Yuanfang, outside of Cold Damage, established a separate section for Febrile Disease, stating first: Summer-heat disease is heat heavier than warmth. Thus, febrile disease is also called summer-heat. Pang Anchang further wrote a chapter on Summer-Heat Disease, classifying it as the febrile disease within Cold Damage. Furthermore, both authors based their descriptions on *Su Wen: Re Bing of the Five Zang Organs*. Thus, the names are the same, but the realities differ. Only Zhu Shi clearly differentiated between febrile disease and heat-stroke without confusion. However, Zhu Shi's "febrile disease" refers to Cold Damage, and his "heat-stroke" refers to Zhong Yue. His meaning is clear and avoids confusion. We should adopt Zhu Shi's nomenclature. The discussions of other schools are not fundamentally different; only the names vary.