肾属寒水。主令在冬。故内经以为闭蛰封藏之本。以欲耗其精。则不能奉若天时。封藏
固密。遂致太阳疏渗。寒邪易侵。若肾脏坚固。即使迫于寒灭受邪轻浅。治之即痊。肾脏虚衰。
略冒寒邪。便尔深重。医药难疗故曰。伤寒偏死肾虚人。良非虚语。
伤寒传变淆讹。症端错杂。且肃杀之气。最为毒烈医者不能博古衡今。漫投汤剂。鲜不
夭枉。致令愤激之说。以不服药为中医。岂其然哉。惟正气实而邪气轻者。或可俟其经尽而愈
。若正气虚而邪气重者。非按法施治。何由得痊。譬如人溺洪涛。命在呼吸。不为援手。而
听其自渡。恐全活者几希矣。
一曰太阳受之。即与少阴俱病。则头痛。（太阳）口干。烦满而渴。（少阴）二日阳明受之
。即与太阴俱病。则身热谵语（阳明）腹满不欲食。（太阴）三日少阳受之。即与厥阴俱病。则耳聋
。（少阳）囊缩而厥。（厥阴）病至六日。腑脏之气俱尽。营卫之气俱绝。则死矣。仲景既论两
感为必死之症。而复日治有先后者。盖不忍坐视。而觊其万一之活也。如下利身痛。则先救
里。不利身痛。则先救表。表症多者发表为急。里症多者。
攻里为先。东垣曰。虚而感之深者必死。实而感之浅者或生。用大羌活汤。十救一二。
春应暖而反寒。夏应热而反凉。秋应凉而反热。冬应寒而反温。非其时而有其气。触冒
之者。沿门遍户。长幼相似。此时行疫症也。春感寒邪。升麻葛根汤。夏感凉邪。调中汤。秋感
热邪。苍术白虎汤。冬感温邪。葳蕤汤。表不愈者。芎苏散。里不愈者。调胃承气汤。或
成大头瘟者。当辨其经。先于鼻额红肿。以致面目肿盛。阳明也。壮热气喘。口干咽痛。脉
数而大。普济消毒饮。耳旁及头角红肿少阳也。往来寒热潮热。口苦咽干。目痛胁痛。小柴
胡汤。加花粉芩翘。发于项上。及脑后项下。目后赤肿者。太阳也。荆芥败毒散。三阳俱受
邪。普济消毒饮。不可峻攻。恐邪气内陷也。虚人兼扶正气。便结者微下之。
The Kidney belongs to Cold Water. Its governing season is Winter. Therefore, the *Neijing* (Inner Canon) regards it as the root of closure, hibernation, and storage. If essence is depleted by sexual indulgence, one cannot conform to the changes of Heaven and Earth, leading to a lack of firmness and density in storage and consolidation. Consequently, the Taiyang channel becomes lax and permeable, making it easy for Cold pathogenic factors to invade. If the Kidneys are solid, even if pressed by severe cold and affected by pathogens, the condition will be superficial, and treatment will lead to recovery. If the Kidneys are deficient and declining, merely encountering Cold pathogenic factors will result in a deep and severe condition, difficult to treat with medicine. Thus it is said, "In Shanghan (Cold Damage), those with Kidney deficiency are more likely to die," which is indeed not an empty statement.
The transmission and transformation of Shanghan are chaotic and prone to error, with symptoms being complex and mixed. Moreover, the肃杀 (desolating/killing) Qi, which is most toxic and fierce, requires physicians to possess broad knowledge of the past and present to weigh circumstances. If they arbitrarily administer decoctions, few will avoid premature death. This has led to the resentful saying that "not taking medicine is the best medical treatment." Is this really the case? Only when Zhengqi (Upright Qi) is substantial and Xieqi (Pathogenic Qi) is light might one wait for the meridians to exhaust the pathogen and recover naturally. If Zhengqi is deficient and Xieqi is heavy, how can one recover without following specific methods of treatment? It is like a person drowning in a flood, with life hanging in the balance; if no hand is extended to help, but left to swim on their own, few will survive.
One scenario is: When the Taiyang channel is affected, Shaoyin simultaneously suffers. This presents with headache (Taiyang symptom), dry mouth, vexation, fullness, and thirst (Shaoyin symptom). On the second day, Yangming is affected, and Taoyin simultaneously suffers. This presents with body heat, delirious speech (Yangming symptom), abdominal fullness, and loss of appetite (Taoyin symptom). On the third day, Shaoyang is affected, and Jueyin simultaneously suffers. This presents with deafness (Shaoyang symptom), retraction of the scrotum, and cold limbs (Jueyin symptom). By the sixth day, the Qi of the Zang-Fu organs is exhausted, and the Ying (Nutritive) and Wei (Defensive) Qi are severed, leading to death. Zhang Zhongjing discussed "Lianggan" (Simultaneous Affection of Exterior and Interior channels) as a fatal condition, yet also stated that treatment has priorities. This is likely out of reluctance to watch patients die, hoping for a sliver of survival. For example, if there is diarrhea and body pain, first rescue the Interior; if there is no diarrhea but body pain, first rescue the Exterior. If Exterior symptoms predominate, releasing the Exterior is urgent; if Interior symptoms predominate, purging the Interior takes precedence. Li Dongyuan said: Those who are deficient and deeply affected will surely die; those who are substantial and lightly affected may live. Using Da Qianghuo Tang (Major Notopterygium Decoction), one or two out of ten may be saved.
Spring should be warm but is instead cold; Summer should be hot but is instead cool; Autumn should be cool but is instead hot; Winter should be cold but is instead warm. Having Qi contrary to the season, those who encounter it affect households across the neighborhood, young and old alike. This is Shixing Yizheng (Seasonal Epidemic Disease). Spring Cold damage uses Shengma Gegen Tang (Cimicifugae and Puerariae Decoction); Summer Cool damage uses Tiaozhong Tang (Regulating the Middle Decoction); Autumn Heat damage uses Cangzhu Baizhu Tang (Atractylodis Macrocephalae and White Tiger Decoction); Winter Warm damage uses Weirui Tang (Anemarrhenae Decoction). If Exterior symptoms persist, use Xiong Su San (Sichuan Lovage and Perilla Powder); if Interior symptoms persist, use Tiaowei Chengqi Tang (Regulating the Stomach and Directing Downward Decoction). If it develops into Datouwen (Great Head Plague), one must differentiate the channel. Initially, redness and swelling of the nose and forehead, leading to severe facial swelling, indicate Yangming channel involvement: high fever, panting, dry mouth, sore throat, rapid and large pulse. Use Puji Xiaodu Yin (Universal Benefit Detoxification Decoction). Redness and swelling around the ears and temporal angles indicate Shaoyang channel involvement: alternating chills and fever, tidal fever, bitter taste, dry throat, eye pain, and hypochondriac pain. Use Xiao Chaihu Tang (Minor Bupleurum Decoction) plus Tianhuafen (Trichosanthes Root), Huangqin (Scutellaria Root), and Lianqiao (Forsythia Fruit). Redness and swelling behind the eyes, occurring at the nape and back of the neck, indicate Taiyang channel involvement. Use Jingjie Baidu San (Schizonepeta and Antidote Powder). If all three Yang channels are affected, use Puji Xiaodu Yin. Do not use harsh purgatives, lest the pathogen sink inward. For deficient individuals, support Zhengqi concurrently. If constipation occurs, use mild purgation.