四时各有主气。客气五方强弱之异兹所举者。不过明脏腑气应与天时并行之义耳。医者当知隅反。
春善病鼽衄。
鼽是鼻塞流涕。衄是流鼻血。鼽属气分。春阳发泄。为阴所闭则鼻塞不通。治宜疏散其寒。衄属血分。春木生火。
动血上冲。干犯清道。鼻为肺窍。木火侮肺。故发衄。治宜清降其火。善病者。谓多此种病也。
仲夏善病胸胁。
胸是两乳中间属心。胁是两乳旁边。属三焦。心是君火。三焦是相火。皆与夏气相应。故仲夏善病胸胁。以火有余。
多发逆满也。
长夏善病洞泻寒中。
长夏未。月湿土主气。脾主湿而恶湿。湿甚则发洞泻阳极于外。无以温养中土。故发寒中之病。观冬月井水温。夏
月井水冷。则知夏月。中宫多寒矣。
秋善病风疟。
风属肝疟属少阳。因风致疟。本系木火为病。而多发于秋令者。木火侮金也。盖秋当肺金主气之时。金气清肃。则
皮毛自敛。膜腠自和设风气鼓动。则为皮毛不得敛。而发寒热。风火相煽。则膜腠不得和。而战栗。溺赤。知此理者。
可得治疟之法矣。
冬善病痹厥。
痹是骨节疼痛。厥是四肢逆冷。肾中阳气。能达于骨节。充于四末。则无此病。冬令寒水气盛。往往肾阳不足。故
多此病。
四时之病不一而足。则此种为多。且知其理。而一切非时之病。理皆可识。
Each of the four seasons has its dominant climate. The variations in the strength and weakness of the Guest Qi (Ke Qi, 客气) among the five directions are not fully detailed here; what is presented merely clarifies the principle that the Qi of the Zang-Fu organs should run in parallel with the timing of Heaven and Earth. Physicians should be able to infer other cases from this example.
In spring, diseases such as nasal obstruction with discharge (Qiu, 鼽) and epistaxis (Nu, 衄) are prevalent.
Qiu refers to nasal obstruction with discharge. Nu refers to nosebleed. Qiu belongs to the Qi level. In spring, Yang Qi tends to disperse outward; if it is obstructed by Yin (Cold), nasal obstruction occurs. Treatment should aim to dissipate the Cold. Nu belongs to the Blood level. In spring, Wood generates Fire, which agitates Blood and causes it to rush upward, invading the clear orifices. The nose is the opening of the Lung. Wood-Fire insults Metal (Lung), leading to epistaxis. Treatment should aim to clear and descend the Fire. "Shan bing" (prone to disease) means being susceptible to these types of illnesses.
In mid-summer, diseases affecting the chest and hypochondrium are prevalent.
The chest, located between the two breasts, corresponds to the Heart. The hypochondrium, located beside the two breasts, corresponds to the Sanjiao (Triple Burner). The Heart governs Ministerial Fire (Jun Huo, 君火), and the Sanjiao governs Official Fire (Xiang Huo, 相火); both correspond to the summer climate. Therefore, in mid-summer, diseases of the chest and hypochondrium are common, primarily because excess Fire often leads to rebellious Qi and fullness.
In late summer, severe diarrhea and cold invasion of the middle jiao are prevalent.
During late summer, Dampness and Earth Qi dominate. The Spleen governs Dampness but dislikes Dampness; excessive Dampness triggers severe diarrhea (Dong Xie, 洞泻). When Yang reaches its extreme outwardly, there is insufficient warmth to nourish the Middle Earth (Spleen/Stomach), resulting in Cold invasion of the middle. Observing that well water is warm in winter and cold in summer reveals that the Middle Jiao is often cold during summer.
In autumn, wind-induced malaria is prevalent.
Wind is associated with the Liver, and malaria is associated with the Shaoyang Gallbladder. Malaria induced by wind originates from Wood-Fire pathology but frequently occurs in autumn due to Wood-Fire insulting Metal (Lung). Autumn is when Lung Metal dominates; Metal's clear and肃 (descending/clearing) nature allows the skin and hair pores to close naturally and the interstices (Mo Cou, 膜腠) to harmonize. If Wind agitates, the skin cannot close, causing alternating chills and fever. If Wind and Fire fan each other, the interstices fail to harmonize, causing shivering and dark urine. Understanding this principle enables one to master the treatment of malaria.
In winter, Bi syndrome (obstruction) and Jue syndrome (reversal/cold limbs) are prevalent.
Bi syndrome refers to pain in the bone joints. Jue syndrome refers to cold extremities. If the Kidney's Yang Qi can reach the bone joints and fill the four extremities, these diseases do not occur. In winter, Cold Water Qi is strong, often leading to insufficiency of Kidney Yang, hence the prevalence of these diseases.
The diseases of the four seasons are numerous, but those mentioned above are common. Furthermore, once the underlying principles are understood, the pathogenesis of any disease occurring out of season can also be recognized.