伤寒温病南北证治。其大纲有不同者。北方天地之气化皆燥。人身呼吸腠理之间。皆燥化也。燥之为政。清泠
而坚削。故其治。常宜兼滋血而舒筋。南方天地之气化皆湿。人身呼吸腠理之间。皆湿化也。湿之为政。混浊而壅
滞。故其治。常宜兼清血而坚筋。又南人乍北。多患疟痢。北人乍南。多患伤寒温热。所以然者。腠理水湿之邪。
为天气所敛。不得熏蒸发泄。透入血脉。气困血滞则为疟。气陷血溃则为痢。下焦久伏之寒。为地气所冲。升腾上
越。或盈溢于三焦。或散布于脉络。寒盛而中焦无热。即为下寒触发之伤寒。中焦积热。同时冲发。即为寒温相伏
之温病。凡如此者。虽有新感表证。俱不宜重用发汗。疟痢。并和血行气以化湿。伤寒。温降而微清之。温热。先
清而后温降之。或曰。子尝论疟痢皆宜透汗。今乃谓虽有新感。不宜重汗。何也。曰南方疟痢。皆是夏伏暑湿。交
秋发病。其时湿热熏蒸。腠理疏豁。若不振卫阳以御表邪。邪气浸灌。来源不断。病何由愈。若至北方。气燥肌敛。
邪气来源已断。故只宜从里化。不得逆其气以虚其表。暗损真元。岂竟不汗哉。不得辛温重剂强汗耳。伤寒温热何
如。曰此必有大汗。然亦非发散之谓也。温之清之。微散以导之待时自作。若迫而汗之。气行而邪不能从。汗出而
热不得退。致成坏病。谁之咎乎。大凡坏病率由治上遗下。治气遗血故也。
伤寒与温病在南北方的证治，其大纲有所不同。北方天地之气化皆偏燥。人身呼吸与腠理之间，皆受燥气影响（即人体通过呼吸和皮肤毛孔与外界交换时，环境干燥之气侵入体内）。燥气主令之时，气候清冷而坚削（指性质清凉寒冷且使万物干枯收缩），因此治疗时常宜兼用滋润血液以舒缓筋脉的方法。南方天地之气化皆偏湿。人身呼吸与腠理之间，皆受湿气影响（即人体通过呼吸和皮肤毛孔与外界交换时，环境潮湿之气侵入体内）。湿气主令之时，气候混浊而壅滞（指性质浑浊黏腻且阻碍气机运行），因此治疗时常宜兼用清解血液以坚固筋脉的方法。
此外，南方人刚到北方，多患疟疾和痢疾；北方人刚到南方，多患伤寒和温热病。之所以如此，是因为南地腠理间的水湿之邪，被北方的天气所收敛，不能通过熏蒸发泄排出体外，反而透入血脉。气机困阻、血液停滞则形成疟疾；气机下陷、血液溃散则形成痢疾。下焦久伏的寒邪，被南方的地气所冲激，升腾上越，或者充盈溢出于三焦，或者散布于脉络之中。若寒气盛而中焦无热，即为下焦寒邪触发导致的伤寒；若中焦积热同时冲发，即为寒热相互潜伏导致的温病。
凡属此类情况，即使有新感表证，也不宜重用发汗法。对于疟疾和痢疾，应并用调和血液、行气化湿的方法。对于伤寒，宜微清降逆。对于温热病，宜先清解而后温降。
有人问：您曾论述疟疾和痢疾都适宜透汗，现在却说即使有新感也不宜重汗，这是为什么？回答说：南方的疟疾和痢疾，都是夏季潜伏的暑湿之邪，到了秋季发病。那时湿热熏蒸，腠理疏阔开放。如果不振奋卫阳以抵御表邪，邪气就会浸灌而入，来源不断，病怎么能痊愈呢？如果到了北方，气候干燥肌肤收敛，邪气的来源已经切断，所以只宜从内部化解，不得违背气机强行发汗以免虚损体表，暗中损伤真元。难道完全不能出汗吗？只是不能用辛温重剂强行发汗罢了。那伤寒和温热病又当如何？回答说：这必然会有大汗出，但这并非指使用发散药物所致。通过温降或清解，微微散发以引导邪气，等待时机自然汗出。如果逼迫其发汗，气行但邪气不能随之排出，汗出而热不退，导致变成坏病，这是谁的过错呢？大凡坏病，大多是由于治疗上部遗漏下部，治疗气分遗漏血分所造成的。
The treatment principles for Cold Damage (Shanghan) and Warm Diseases (Wenbing) differ significantly between the North and the South. In the North, the Qi transformation of Heaven and Earth is predominantly dry. The human body's respiration and interstices (Couli, 腠理 - pores and muscle intervals) are also influenced by dryness. When Dryness governs, the climate is cool and crisp, causing contraction; thus, treatment often requires nourishing Blood to relax sinews. In the South, the Qi transformation of Heaven and Earth is predominantly damp. The human body's respiration and interstices are influenced by dampness. When Dampness governs, the climate is turbid and stagnant; thus, treatment often requires clearing Blood to strengthen sinews.
Furthermore, Southerners moving to the North often suffer from Malaria (Nüe, 疟疾) and Dysentery (Li, 痢疾); Northerners moving to the South often suffer from Cold Damage and Warm Diseases. This occurs because the water-damp pathogenic factors in the interstices of Southerners are constrained by the Northern climate, preventing them from being evaporated and excreted through sweating, leading them to penetrate into the blood vessels. Qi stagnation and Blood stasis result in Malaria; Qi sinking and Blood溃散 (scattering/rupture) result in Dysentery. Conversely, Cold latent in the Lower Jiao (Lower Burner, 下焦) is stirred up by Southern Earth Qi, rising and ascending. It may overflow into the Triple Burner (Sanjiao, 三焦) or disperse into the meridians. If Cold is excessive while the Middle Jiao (Middle Burner, 中焦) lacks Heat, it triggers Cold Damage due to Lower Jiao Cold. If Middle Jiao accumulated Heat erupts simultaneously, it results in Warm Disease caused by latent Cold and Heat.
In such cases, even if there are new exterior manifestations, heavy diaphoresis (sweating therapy, 发汗) is contraindicated. For Malaria and Dysentery, harmonizing Blood and promoting Qi circulation to transform Dampness should be used. For Cold Damage, mild clearing and descending is appropriate. For Warm Diseases, clearing first followed by warming and descending is indicated.
One might ask: "You previously argued that Malaria and Dysentery should be treated with diaphoresis to vent pathogens; now you say heavy sweating is unsuitable even for new exterior signs. Why?" I reply: "Southern Malaria and Dysentery stem from Summer-Heat and Dampness latent since summer, manifesting in autumn. At that time, Damp-Heat steams and boils, and the interstices are open. If Wei Yang (Defensive Yang, 卫阳) is not strengthened to resist exterior pathogens, pathogenic factors will flood in continuously, and the disease cannot heal. However, upon arriving in the North, the air is dry and skin pores constrict; the source of pathogens is cut off. Therefore, treatment should focus on resolving internally. One must not force sweating against the natural Qi flow, which would empty the exterior and secretly damage True Yuan (True Origin/Essence, 真元). Does this mean no sweating at all? No, it simply means avoiding strong acrid-warm formulas to force sweating."
"What about Cold Damage and Warm Diseases?" I reply: "These inevitably involve profuse sweating, but this is not achieved through dispersing agents. By using warming/descending or clearing methods, slight dispersion guides the pathogens, waiting for the right time for spontaneous sweating. If one forces sweating, Qi moves but pathogens do not exit; sweat comes out but heat does not recede, leading to complicated diseases (Huabing, 坏病). Whose fault is this? Generally, complicated diseases arise from treating the upper while neglecting the lower, or treating Qi while neglecting Blood."