或曰∶人秉阴阳水火而生，总属一气血耳！余观
《伤寒论》注疏，子以皮肤肌腠、五脏六腑，各有所主之气，恐于阴阳之理相背欤！曰∶子不明阴阳离合之道，
合则为一，离则有三。太阳之气，生于膀胱，而主于肤表。少阳之气，生于肾脏，而通于肌腠，故
《灵枢经》曰∶三焦膀胱者，腠理毫毛其应。盖太阳之气主皮毛，三焦之气充肌腠。此太少之气，由下焦之
所生。若夫阳明之气，乃水谷之悍气，别走阳明，即行阳行阴之卫气，由中焦之所生。此三阳之气各有别
也。三阴者，五脏之气也。肺气主皮毛，脾气主肌肉，心气通血脉，肝气主筋，肾气主骨。此五脏之
气各有所主也。夫气生于精，阳生于阴。胃腑主化生水谷之精，是以荣、卫二气，生于阳明。膀胱者，州
都之官，精液藏焉，而太阳之气，生于膀胱。肾为水脏，受五脏之精而藏之，故少阳之气，发于肾脏。水
谷入胃，津液各走其道，五脏主藏精者也。是三阴之气，生于五脏之精，故欲养神气者。先当守其精焉。夫
一阴一阳者，先天之道也；分而为三阴三阳者，后天之道也。子不明阴阳之离合，血气之生始，是谓失道。
客曰∶三阴三阳，敬闻命矣，请言其合也。曰∶所谓合者，乃先天之一气，上通于肺，合宗气而司呼吸者也。
夫有生之后，皆属后天，故藉中焦水谷之精、以养先
天之精气，复藉先天之元气，以化水谷之精微，中、下二焦，互相资益。故论先后天之精气者，养生之道
也；分三阴三阳者，治病之法也。如邪在皮肤，则伤太阳之气，或有伤于肺；邪在肌腠，则伤少阳、阳
明，或有伤于脾，邪中少阴，则有急下急温之标本；邪中厥阴，则有或寒或热之阴阳。此在天之六气，伤
人之三阴三阳，犹恐其不能分理，而可以一气论乎？若谓正气虚者，补中、下二焦之元气，以御六淫之邪，则可。
有人问道：“人禀受阴阳水火之气而生，归根结底只是一团气血罢了！我观察《伤寒论》的注疏，您认为皮肤、肌肉纹理以及五脏六腑，各自有其所主的气，这恐怕与阴阳的道理相违背吧！”
我说：“你不明白阴阳离合的道理。合起来则为一，分开来则为三。太阳之气，产生于膀胱，而主宰体表的皮毛。少阳之气，产生于肾脏，而通达于肌肉纹理，所以《灵枢经》说：‘三焦和膀胱，其反应体现在腠理和毫毛上。’大概太阳之气主管皮毛，三焦之气充养肌肉纹理。这种太阴（注：原文为太少，指太阳与少阳）之气，是由下焦所生成的。至于阳明之气，是水谷中剽悍滑利的气，别行于阳明经，也就是运行于阳分和阴分的卫气，由中焦所生成。这三种阳经之气各有区别。
三阴经，是五脏之气。肺气主管皮毛，脾气主管肌肉，心气通达血脉，肝气主管筋脉，肾气主管骨骼。这是五脏之气各自有所主管的缘故。气生于精，阳生于阴。胃腑主要化生水谷之精微，因此营气和卫气，都产生于阳明（胃）。膀胱是州都之官，储藏精液，而太阳之气，产生于膀胱。肾是水脏，接受并储藏五脏的精气，所以少阳之气，发源于肾脏。水谷进入胃中，津液各走其道，五脏是主藏精气的器官。因此三阴之气，产生于五脏之精，所以想要养护神气的人，应当先守住精气。
所谓一阴一阳，是先天的道理；分为三阴三阳，是后天的道理。你不明白阴阳的离合以及气血的生成始末，这就叫做失道。
客人说：“关于三阴三阳，我已恭敬地听明白了，请再讲讲它们的‘合’。”
我说：“所谓的‘合’，是指先天的一气，向上通达于肺，与宗气相合而主持呼吸。人有生之后，都属于后天，所以借助中焦水谷之精，来滋养先天的精气；又借助先天的元气，来化生水谷的精微物质，中焦和下焦互相资助有益。所以论述先后天精气的是养生之道；分辨三阴三阳的是治病之法。如果邪气在皮肤，就会损伤太阳之气，或者伤及肺；邪气在肌肉纹理，就会损伤少阳、阳明，或者伤及脾；邪气中于少阴，就有急下或急温的标本治法；邪气中于厥阴，就有或寒或热的阴阳变化。这是在天之六气，伤害人之三阴三阳，尚且担心不能分清条理，怎么能用一气来笼统论述呢？如果说正气虚弱，补益中焦、下焦的元气，以抵御六淫邪气，那就可以。”
A questioner asked: "Humans are born by inheriting Yin and Yang, Water and Fire, ultimately belonging to nothing but Qi and Blood! In my observation of the commentaries on *Shanghan Lun* (Treatise on Cold Damage Diseases), you assert that the skin, muscle clefts, Zang-Fu organs, each have their own governing Qi. This seems contrary to the principles of Yin and Yang!"
I replied: "You do not understand the Dao of separation and union of Yin and Yang. When united, it is one; when separated, it becomes three. The Qi of Taiyang (Greater Yang) is generated in the Bladder and governs the body surface. The Qi of Shaoyang (Lesser Yang) is generated in the Kidney and connects with the muscle clefts. Thus, the *Ling Shu* (Spiritual Pivot) states: 'The Sanjiao and Bladder correspond to the clefts and hair follicles.' Generally, the Qi of Taiyang governs the skin and hair, while the Qi of Sanjiao (Triple Burner) nourishes the muscle clefts. These Qi of Taiyang and Shaoyang are generated from the Lower Jiao. As for the Qi of Yangming (Yang Brightness), it is the fierce Qi of food and fluids, which takes a separate course through the Yangming channel; this is the Wei Qi (Defensive Qi) that circulates in the Yang and Yin aspects, generated from the Middle Jiao. Thus, the Qi of these three Yang channels has its own distinction.
The three Yin channels represent the Qi of the five Zang organs. Lung Qi governs the skin and hair; Spleen Qi governs the muscles; Heart Qi connects with the blood vessels; Liver Qi governs the sinews; Kidney Qi governs the bones. This is because the Qi of each Zang organ has its specific governance. Qi is generated from Essence, and Yang is generated from Yin. The Stomach primarily transforms and produces the essence of food and fluids; therefore, Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi) are generated from Yangming (Stomach). The Bladder is the official of the reservoir, storing fluids, and the Qi of Taiyang is generated from the Bladder. The Kidney is the water organ, receiving and storing the essence of the five Zang organs; thus, the Qi of Shaoyang originates from the Kidney. When food and fluids enter the stomach, the Jin Ye (Body Fluids) follow their respective pathways, and the five Zang organs are responsible for storing essence. Therefore, the Qi of the three Yin channels is generated from the essence of the five Zang organs. Hence, those who wish to nourish Shen Qi (Spirit Qi) must first preserve their Jing (Essence).
The concept of one Yin and one Yang is the Dao of the Pre-heaven (Innate); dividing into three Yin and three Yang is the Dao of the Post-heaven (Acquired). If you do not understand the separation and union of Yin and Yang, nor the origin and generation of Qi and Blood, this is called losing the Dao.
The guest said: "Regarding the three Yin and three Yang, I have respectfully heard your instructions. Please speak of their 'union'."
I said: "What is meant by 'union' is the single Qi of the Pre-heaven, ascending to connect with the Lung, uniting with Zong Qi (Gathering Qi) to govern respiration. After birth, all belong to the Post-heaven state. Therefore, we rely on the essence of food and fluids from the Middle Jiao to nourish the Pre-heaven Jing Qi; and again, we rely on the Pre-heaven Yuan Qi (Original Qi) to transform the fine essences of food and fluids. The Middle and Lower Jiao mutually support and benefit each other. Thus, discussing the Jing Qi of the Pre-heaven and Post-heaven pertains to the Dao of health preservation; distinguishing the three Yin and three Yang pertains to the methods of treating disease. If pathogenic factors are in the skin, they injure the Qi of Taiyang, or potentially injure the Lung; if pathogenic factors are in the muscle clefts, they injure Shaoyang and Yangming, or potentially injure the Spleen; if pathogenic factors strike Shaoyin, there are urgent purgation or urgent warming treatments addressing both root and branch; if pathogenic factors strike Jueyin (Terminal Yin), there are patterns of either cold or heat involving Yin and Yang. This refers to the Six Qi (Pathogenic Factors) in Heaven injuring the three Yin and three Yang in humans. We still fear that the distinctions cannot be clearly reasoned; how can one discuss it as a single Qi? However, if one posits that due to deficiency of Righteous Qi, one tonifies the Yuan Qi of the Middle and Lower Jiao to resist the Six Exogenous Pathogens, then this approach is acceptable."