四序流行，春生夏长，秋收冬藏。故春为风木，秋为燥金，冬为寒水，各司其令。惟夏则暑热湿三气迭乘，合
操其柄，此盖大化循环之运，不期然而然，而亦不得不然也。所谓不期然而然者，何也？天一生水，贞下起
元，由水生木，由木生火，至是而天气下降，地气上腾，大生广生，百物蕃阜，此所谓不期然而然者也。所谓
不得不然者何也？夏为火令，秋为金令，由夏入秋，乃火下起金，不惟不能相生，而反相克，秋令不几于或
息乎！全赖地气上腾，长夏土旺，由火生土，借土生金，此又大化斡旋之妙用，四序方得流行，生克方不颠
倒，所谓不得不然者此也。但暑热之气自上而下，湿气自下而上，人在其中，无时无处不受其熏蒸燔灼，
致病已非一端，又况起居不慎，饮食不节，其受病尚可问乎！《金匮》有痉湿 之训，后贤推而广之，立方
愈多，醇驳互见。盖伤寒有痉病，时邪亦有痉病，而时邪之痉，与伤寒之痉，又复不同。三气之痉，只须究其
致病之由，或由风热，或由暑热，或由湿热，见症治症，直截了当。若牵涉伤寒之痉，较量比例，虽繁称博引，
更令人滋惑矣。且三气为病，非有沉寒痼冷，如冬月伤寒之比，若拘执太阳篇中之痉病，动辄麻黄、桂枝，
何异抱薪救火乎！兹特举症于前，列方于后，以便检阅。
The four seasons circulate in sequence: spring generates, summer grows, autumn harvests, and winter stores. Therefore, spring corresponds to Wind-Wood, autumn to Dryness-Metal, and winter to Cold-Water, each governing its respective seasonal command. Only in summer do the three qi of Summerheat (Shu), Heat (Re), and Dampness (Shi) alternate in their invasion, jointly controlling the climate. This is due to the cycle of the Great Transformation, occurring naturally without intent, yet inevitably so.
What is meant by "occurring naturally without intent"? Heaven generates Water first; as Winter ends, the primal Yang arises. From Water comes Wood, from Wood comes Fire. By this stage, Heavenly Qi descends and Earthly Qi ascends, allowing for extensive generation and proliferation, with all things flourishing abundantly. This is what is meant by "occurring naturally without intent."
What is meant by "inevitably so"? Summer is governed by the Fire Command, and Autumn by the Metal Command. Transitioning from Summer to Autumn involves Fire descending and Metal rising. This not only fails to generate but instead creates a restraining relationship. Would not the Autumn Command nearly cease to exist? It relies entirely on the ascent of Earthly Qi and the prosperity of Earth during Late Summer. From Fire comes Earth, and through Earth, Metal is generated. This is the subtle function of the Great Transformation's rotation, allowing the four seasons to circulate in order and preventing the reversal of generating and restraining cycles. This is what is meant by "inevitably so."
However, the qi of Summerheat and Heat descends from above, while Dampness rises from below. Humans situated within this environment are subjected to steaming and scorching at all times and places. The causes of disease are manifold. Furthermore, if one is careless in daily life and irregular in diet, how severe can the resulting illness be? *Jin Gui Yao Lue* (Essential Prescriptions of the Golden Cabinet) contains teachings on Spasm (Jing) and Dampness (Shi). Later scholars expanded upon these, creating numerous prescriptions, among which both effective and ineffective ones are intermingled.
Cold Damage (Shanghan) may involve Spasm, and pathogenic factors of the time (Shi Xie) may also involve Spasm. However, Spasm caused by Shi Xie differs fundamentally from that caused by Shanghan. For spasms caused by the three qi (Summerheat, Heat, Dampness), one need only investigate the etiology—whether due to Wind-Heat, Summerheat-Heat, or Dampness-Heat—and treat the symptoms directly. If one conflates these with Spasm from Shanghan and attempts to draw analogies, frequent citation of classics will only lead to greater confusion.
Moreover, diseases caused by these three qi do not involve the deep cold and entrenched chill comparable to Winter Shanghan. To rigidly adhere to the theory of Spasm in the Taiyang Chapter of *Shanghan Lun*, and routinely employ Mahuang Tang (Ephedra Decoction) or Guizhi Tang (Cinnamon Twig Decoction), is akin to adding fuel to the fire. Here, symptoms are listed first, followed by prescriptions, for ease of reference.