伤寒振者。何以明之。振者森然若寒。耸然振动者是也。伤寒振者。皆责其虚寒也。
至于欲汗之时。其人必虚。必蒸蒸而振。却发热汗出而解。振近战也。而轻者为振
矣。战为正与邪争。争则为鼓栗而战。振但虚而不至争。故止耸动而振也。下后复
发汗振寒者。谓其表里俱虚也。亡血家发汗。则寒栗而振者。谓其血气俱虚也。诸
如此者。止于振耸尔。其振振欲擗地者。有身为振振摇者。二者皆发汗过多。亡阳
经虚。不能自主持。故身为振摇也。又非若振栗之比。经曰。若吐若下后。心下逆满。
气上冲胸。起则头眩。发汗则动经。身为振振摇者。茯苓桂枝白术甘草汤主之。太
阳病。发汗不解。其人仍发热。心下悸。头眩身 动。振振欲擗地者。真武汤主之。二
汤者。皆温经益阳。滋血助气之剂。经虚阳弱得之。未有不获全济之功者。
伤寒战栗。何以明之。战栗者。形相类而实非一也。合而言之。战栗非二也。析而分
之。有内外之别焉。战者身为之战摇者是也。栗者心战是也。战之与栗。内外之诊
也。昧者通以为战栗也。通为战栗。而不知有逆顺之殊。经曰。胃无谷气。脾涩不通。
口急不能言。战而栗者。即此观之。战之与栗。岂不异哉。战之与振。振轻而战重也。
战之与栗。战外而栗内也。战栗者。皆阴阳之争也。伤寒欲解。将汗之时。正气内实。
邪不能与之争。则便汗出而不发战也。邪气欲出。其人本虚。邪与正争。微者为振。
甚者则战。战退正胜而解矣。经曰。病有战而汗出。因得解者何也。其人本虚。是以
发战者是也。邪气外与正气争则为战。战其愈者也。邪气内与正气争则为栗。栗
为甚者也。经曰。阴中于邪。必内栗也。表气微虚。里气不守。故使邪中于阴也。方其
里气不守。而为邪中于正气。正气怯弱。故成栗也。战者正气胜。栗者邪气胜也。伤
寒六七日。欲解之时。当战而汗出。其有但心栗而鼓颔。身不战者。已而遂成寒逆。
似此证多不得解。何者。以阴气内盛。正气太虚。不能胜邪。反为邪所胜也。非大热
剂。与其灼艾。又焉得而御之。
伤寒中的“振”，该如何阐明呢？所谓“振”，是指身体感到森然寒冷，耸动颤抖的状态。伤寒出现“振”的症状，都是因为责之于虚寒。
到了将要出汗的时候，病人必然正气虚弱，必定会出现蒸蒸而振（发热并伴随颤抖），随后发热出汗而病愈。“振”接近于“战”，但较轻的称为“振”。 “战”是正气与邪气相争，相争则表现为鼓栗而战；“振”仅仅是因为虚弱，并未达到相争的程度，所以只是耸动而颤抖。
经过攻下法后又发汗，出现恶寒颤抖的，是因为表里两虚。亡血之人若发汗，出现寒栗而振的，是因为气血俱虚。诸如此类的情况，仅止于振耸而已。至于那种“振振欲擗地”（身体剧烈震颤想要扑倒在地）或“身为振振摇”（身体震颤摇晃）的情况，都是由于发汗过多，导致亡阳、经脉空虚，不能自主控制，所以身体震颤摇晃。这又不同于振栗的情况。医经说：如果经过吐法或下法后，心下逆满，气上冲胸，起身则头晕目眩，此时若再发汗则会扰动经脉，导致身体震颤摇晃，应用茯苓桂枝白术甘草汤主治。太阳病，发汗后病未解，病人仍然发热，心下悸动，头晕，身体动摇，剧烈震颤想要扑倒地的，应用真武汤主治。这两张方剂，都是温通经脉、补益阳气、滋养血液、辅助气机的药剂。对于经脉虚弱、阳气衰弱者服用，没有不获得痊愈功效的。
伤寒中的“战栗”，该如何阐明呢？“战”和“栗”外形相似但实际上并非同一回事。合起来说，战栗是一个整体概念；分开来说，则有内外的区别。“战”是指身体发生战摇，“栗”是指内心恐惧颤抖（或指牙齿打颤等内在表现）。“战”与“栗”是判断内外病症的依据。愚昧的人将它们混同为战栗，不知道其中有顺证与逆证的差异。医经说：“胃中无谷气，脾脉涩滞不通，口唇紧急不能言语，出现战而栗的现象。”由此观之，“战”与“栗”难道不相同吗？“战”与“振”相比，振轻而战重；“战”与“栗”相比，战在外而栗在内。
“战栗”，都是阴阳二气相争的表现。伤寒病将要解除，即将出汗的时候，如果正气内部充实，邪气不能与之相争，就会直接出汗而不发生战栗。如果邪气想要外出，但病人本身体质虚弱，邪气与正气相争，轻微的表现为“振”，严重的则表现为“战”。战退之后，正气胜邪而病愈。医经说：“有的病人战栗后出汗，因而得以痊愈，这是为什么呢？是因为病人本来体质虚弱，所以发生战栗。”邪气在外部与正气相争就表现为“战”，战是向愈的表现；邪气在内部与正气相争就表现为“栗”，栗是病情较重的表现。医经说：“阴分受到邪气侵袭，必然会出现内部的栗。”这是因为表气微弱虚弱，里气不能固守，所以使邪气侵入阴分。当里气不能固守，被邪气侵犯正气时，正气怯弱，从而形成“栗”。“战”代表正气胜，“栗”代表邪气胜。
伤寒六七日，是病欲解的时候，应当战栗后出汗。如果有仅仅心中栗栗不安且下巴打颤，身体不战栗的，随后就会变成寒逆证。像这样的证候大多不能自愈。为什么呢？因为阴气内盛，正气太虚，不能战胜邪气，反而被邪气所战胜。如果不是用大热之剂，或者施以艾灸，又怎么能抵御它呢？
In Taiyang disease (Taiyang Disease), what is meant by "Zhen" (Trembling/Shivering)? "Zhen" refers to a state where the body feels intensely cold and trembles or quivers. The occurrence of "Zhen" in Taiyang disease is attributed to deficiency-cold (Xu Han).
When sweating is about to occur, the patient must be deficient. There will inevitably be a sensation of steaming heat accompanied by trembling ("Zheng Zheng Er Zhen"), followed by fever, sweating, and resolution of the disease. "Zhen" is close to "Zhan" (Shivering/Chattering), but the milder form is called "Zhen". "Zhan" represents the struggle between righteous Qi (Zheng Qi) and pathogenic factors (Xie Qi); this struggle manifests as shivering with chattering teeth. "Zhen", however, arises merely from deficiency without reaching the stage of struggle, thus manifesting only as quivering and trembling.
After purgation followed by diaphoresis, if chills and trembling occur, it indicates that both the exterior and interior are deficient. If a patient who has lost blood undergoes diaphoresis and experiences cold chattering and trembling, it indicates that both blood and Qi are deficient. In such cases, there is only quivering and trembling. However, in cases where the patient trembles violently as if wanting to fall to the ground ("Zhen Zhen Yu Pi Di") or where the body trembles and sways ("Shen Wei Zhen Zhen Yao"), these result from excessive diaphoresis leading to Yang collapse and deficiency of the meridians, causing the body to lose autonomous control and tremble. This differs from "Zhen Li" (Shivering and Chattering). The Classic states: "If after emesis or purgation, there is fullness and counterflow of Qi below the heart, Qi rushing up to the chest, dizziness upon standing, and subsequent diaphoresis disturbs the meridians causing the body to tremble and sway, Poria, Cinnamon Twig, Atractylodes Macrocephala and Licorice Decoction (Fuling Guizhi Baizhu Gancao Tang) should be administered." In Taiyang disease, if diaphoresis fails to resolve the condition, and the patient still has fever, palpitations below the heart, dizziness, body movement, and trembles violently as if wanting to fall to the ground, Asarum and Prepared Aconite Decoction (Zhenwu Tang) should be administered. Both of these formulas are agents that warm the meridians, benefit Yang, nourish blood, and assist Qi. For those with meridian deficiency and weak Yang, their use invariably leads to complete recovery.
What is meant by "Zhan Li" (Shivering and Chattering) in Taiyang disease? Although "Zhan" and "Li" appear similar, they are essentially different. Collectively referred to as "Zhan Li," they constitute one concept; analytically distinguished, they have differences between interior and exterior. "Zhan" refers to the physical shaking of the body. "Li" refers to internal trembling or fear (often manifesting as chattering teeth or inner dread). "Zhan" and "Li" serve as diagnostic indicators for exterior and interior conditions. Ignorant practitioners conflate them into "Zhan Li," unaware of the distinction between favorable (Shun) and unfavorable (Ni) patterns. The Classic states: "When the Stomach lacks Grain Qi and the Spleen is stagnant and blocked, the mouth becomes tight and speech is impaired, resulting in shivering and chattering." From this, we see that "Zhan" and "Li" are indeed distinct. Comparing "Zhan" and "Zhen," "Zhen" is mild and "Zhan" is severe. Comparing "Zhan" and "Li," "Zhan" is exterior while "Li" is interior.
"Zhan Li" represents the struggle between Yin and Yang. When Taiyang disease is about to resolve and sweating is imminent, if the Righteous Qi is internally solid, Pathogenic Factors cannot struggle with it, and sweating occurs directly without shivering. If Pathogenic Factors attempt to exit but the patient is originally deficient, Pathogenic Factors and Righteous Qi struggle. Mild struggle manifests as "Zhen"; severe struggle manifests as "Zhan". After the struggle subsides, Righteous Qi prevails, and the disease resolves. The Classic states: "Why do some patients resolve through shivering followed by sweating? It is because the patient was originally deficient, hence shivering occurs." When Pathogenic Factors struggle with Righteous Qi externally, it manifests as "Zhan"; "Zhan" indicates healing. When Pathogenic Factors struggle with Righteous Qi internally, it manifests as "Li"; "Li" indicates a more severe condition. The Classic states: "When Yin is attacked by pathogens, internal chattering (Li) necessarily occurs." This is because exterior Qi is slightly deficient and interior Qi does not hold fast, allowing pathogens to enter Yin. When interior Qi fails to hold and pathogens attack the Righteous Qi, the Righteous Qi becomes timid, forming "Li". "Zhan" signifies Righteous Qi prevailing; "Li" signifies Pathogenic Factors prevailing.
In Taiyang disease, on the sixth or seventh day, when resolution is expected, shivering followed by sweating should occur. If there is only internal chattering and chattering of the jaw, without body shivering, it will subsequently develop into Cold Reversal (Han Ni). Such patterns rarely resolve spontaneously. Why? Because Yin Qi is abundant internally and Righteous Qi is too deficient to overcome the pathogens, instead being overcome by them. Unless large hot-decoctions are used, or moxibustion is applied, how can this be countered?