命门真火，藏于两肾之中，性门真水，藏于一心之内。人但言命门真火，而不参究性门真水何也？因真阳之火，能
生真阴之水故也。殊不知性命相生，水火不可以一息不交。天一所生之水，为我生身之始，水中能生真火，人皆未究。
况保真阴之水，则真阳之火常存而不散；若真阴一衰，则真阳无附，飞扬上越，变为邪火，能返涸真阴之水，岂不危哉！
火性本燥烈发扬，而肾中相火偏职闭藏，水性本柔弱蛰藏，而心精三合，独主清利。则知性以位变，水火本无二气。
嘘气即有水，阳化阴也，蒸水即有气，阴化阳也；灯因膏而不灭，阳根据阴也，水因火而不冰，阴根据阳也。相需如此，可
以知其情性矣。
补心气，益心精而不见效者，则知命门火衰、肾水不足，何也？命门之火，即心火之根，肾水之精，即心精之源。
心无水则孤火上逆，肾无火则寒水下凝。水弱火炎，则肺金受克，阳焰飞扬于上焦，而生咳喘、咯血等病，下虚则上盛
也。火弱水刚，则肝木失养，浊阴凝结于下焦，而生癃闭、壅肿、精寒等病，上虚则下实也。水火两平，阴阳斯无偏胜。
脾之权在肾，胃之权在心，自下而上水滋土，自上而下火生土也。脾土属阴，生于相火而健行不息，胃土属阳，传
导于大肠而容受无穷，总在主纳之肾，于是土以火生也。脾虚则胃滞而不食，脾实则胃运而能食，总在主出之肺，于是
气机流动也。故凡治脾胃，当以调肺气，交心肾为先。
人身之痰，最能为害。势涌如潮，势衰如汐。风、寒、湿、燥，随气而生，体实、体虚，随人而致。浊则浓，清则
稀。五藏六腑无盛痰之所，上下升降无时而定，又与正气不两立，殆犹天地间阴云瘴雾耳。
周身气血，无不贯通。故古人用针通其外，由外及内，以和气血；用药通其里，由内及外，以和气血，其理一而已
矣。至于通则不痛，痛则不通，盖指本来原通，而今塞者言，或在内，或在外，一通则不痛，宜十二经络藏府，各随其
处而通之，若通别处，则痛处未知，而他处反为掣动矣。
补、戒急授而骤壅，伐、戒亟夺而峻利，用之不当，皆能致害。故攻热失宜，热未去而寒复作，寒热各踞于其所，
反致温凉并禁，良医莫措矣；攻寒亦然。
人但知冬不藏精者致病，而不知夏不藏精者更甚焉。尝见怯弱之人，而当酷暑，每云气欲闷绝，可知中 而死者，
直因气之闷绝也。夫人值摇精，恒多气促，与当暑之气闷不甚相远。《经》曰∶“热伤气”，又曰∶“壮火食气。”余故曰夏
令之炎威，甚于冬令之寒，苟不藏精，壮者至秋而发为伏暑，怯者即中 而死。
命门中的真火，藏匿于两肾之中；性门中的真水，蕴藏于一心之内。世人只谈论命门的真火，却不深入探究性门的真水，这是为什么呢？这是因为真阳之火能够生发真阴之水的原因。殊不知性命相互滋生，水火二者不可以有一刻不交融。由天一所生的水，是我们生命形成的开始，水中能生出真火，人们都未曾深入研究。
况且保全真阴之水，那么真阳之火就能常存而不消散；如果真阴一旦衰弱，那么真阳就没有依附，就会飞扬上越，变成邪火，反而耗竭真阴之水，这难道不危险吗！
火的性质本来燥烈而发扬，但肾中的相火（寄居于肾的命门之火）却偏重于闭藏；水的性质本来柔弱而蛰伏隐藏，但心的精血三合（心主血脉、藏神等功能的综合），唯独主管清利。由此可知，性（心/火）因位置不同而变化，水火原本没有二种气。
嘘气时就有水产生，这是阳化阴的过程；蒸腾水时就有气产生，这是阴化阳的过程；灯因为膏脂而不熄灭，是阳根据于阴；水因为有火而不结冰，是阴根据于阳。相互需要达到这种程度，就可以知道它们的性情了。
补益心气、滋养心精却不见效的，就知道是命门火衰、肾水不足，为什么呢？命门的火，就是心火的根基；肾水的精，就是心精的来源。心没有水则孤火上逆，肾没有火则寒水下凝。水弱火炎，则肺金受到克制，阳焰飞扬在上焦，从而产生咳嗽、气喘、咯血等疾病，这是下虚导致上盛。火弱水刚（此处指水寒之气盛），则肝木失去滋养，浊阴凝结在下焦，从而产生小便不通、肿胀、精冷等疾病，这是上虚导致下实。水火两者平衡，阴阳才没有偏胜。
脾的功能权柄在于肾，胃的功能权柄在于心，自下而上水滋润土（脾），自上而下火生土（脾）。脾土属于阴，生于相火而健运不息；胃土属于阳，传导给大肠而容纳无穷，总归由主纳气的肾来主宰，于是土是由火所生。脾虚则胃停滞而不想进食，脾实则胃运化而能进食，总归由主出气的肺来调节，于是气机流动。所以凡是治疗脾胃病，应当以调理肺气、交通心肾为先务。
人身上的痰，最能为害。势涌如潮水，势衰如退潮。风、寒、湿、燥，随气而生；体质实、体质虚，随人而致。浊则浓稠，清则稀薄。五脏六腑没有不产生痰的地方，上下升降没有固定的时间，又与正气不能共存，大概就像天地间阴云瘴雾一样。
周身的气血，无不贯通。所以古人用针疏通外部，由外及内，来调和气血；用药疏通内部，由内及外，来调和气血，其中的道理是一样的。至于“通则不痛，痛则不通”，大概是指本来通畅，现在堵塞的情况而言，或者在内，或者在外，一处通畅就不痛了，应该针对十二经络脏腑，各自在其所在之处进行疏通，如果疏通别处，则疼痛的地方还不知道，而其他部位反而会被牵动。
补法，忌讳急于给予而突然壅滞；泻法，忌讳急切攻夺而药性峻猛。使用不当，都能导致危害。所以攻伐热邪失当，热邪未去而寒邪又作，寒热各据其位，反而导致温凉药物都禁用，良医也无从措手了；攻伐寒邪也是如此。
人们只知道冬天不藏精会导致疾病，却不知道夏天不藏精更严重。曾见到怯弱的人，在酷暑时节，常说气闷得快要窒息，可知中暑而死的人，直接是因为气机闷绝所致。人在房事泄精后，常常多气短促，这与暑天的气闷不相上下。《内经》说：“热伤气”，又说：“壮火食气。”所以我说道：夏天的炎热威势，胜过冬天的寒冷，如果不藏精，强壮的人在秋天发作为伏暑，怯弱的人就因中暑而死。
The True Fire of the Mingmen (Gate of Life) is stored within the two Kidneys, and the True Water of the Xingmen (Gate of Nature) is stored within the single Heart. People only speak of the True Fire of the Mingmen, but do not investigate what the True Water of the Xingmen is. Why? Because the True Yang Fire can generate the True Yin Water. Little do they know that Xing and Ming mutually generate each other, and Water and Fire cannot fail to interact for even a moment. The Water generated by Tianyi (One in Heaven) is the beginning of our bodily formation; within this Water, True Fire can be generated, yet people have not thoroughly investigated this.
Moreover, preserving the True Yin Water allows the True Yang Fire to remain constant and not dissipate; if True Yin declines, True Yang has no attachment, flies upward and outward, transforming into Pathogenic Fire, which can then deplete the True Yin Water. Is this not dangerous!
The nature of Fire is originally dry, fierce, and expansive, yet the Ministerial Fire (Xianghuo, an auxiliary fire residing in the Kidney) in the Kidney tends toward closure and storage. The nature of Water is originally soft, weak, and hibernating, yet the Essence of the Heart, through its tripartite integration, exclusively governs clarity and drainage. Thus we know that Xing (Heart/Fire) changes according to position; Water and Fire are originally not two distinct Qi.
Exhaling produces Water; this is Yang transforming into Yin. Evaporating Water produces Qi; this is Yin transforming into Yang. A lamp does not extinguish because of the oil/grease; this is Yang relying on Yin. Water does not freeze because of Fire; this is Yin relying on Yang. They require each other in this manner, allowing us to understand their natures.
When tonifying Heart Qi and benefiting Heart Essence yields no effect, one knows it is due to the decline of Mingmen Fire and insufficiency of Kidney Water. Why? The Fire of the Mingmen is the root of Heart Fire; the Essence of Kidney Water is the source of Heart Essence. If the Heart lacks Water, solitary Fire rebels upward; if the Kidney lacks Fire, Cold Water condenses downward. When Water is weak and Fire flares, Metal of the Lung is overcontrolled; Yang flames fly in the Upper Jiao, generating diseases such as cough, asthma, and hemoptysis. This is Lower Deficiency leading to Upper Excess. When Fire is weak and Water is rigid (cold), Wood of the Liver loses nourishment; turbid Yin coagulates in the Lower Jiao, generating diseases such as strangury, edema/swelling, and cold sperm. This is Upper Deficiency leading to Lower Excess. When Water and Fire are balanced, Yin and Yang have no excess or deficiency.
The authority of the Spleen lies in the Kidney; the authority of the Stomach lies in the Heart. From below upward, Water moistens Earth (Spleen); from above downward, Fire generates Earth (Spleen). Spleen Earth belongs to Yin, born from Ministerial Fire, moving vigorously without cease. Stomach Earth belongs to Yang, transmitting to the Large Intestine, receiving infinitely. All are governed by the Kidney which controls grasping Qi; thus Earth is generated by Fire. When Spleen is deficient, Stomach stagnates and appetite fails; when Spleen is full/excess, Stomach transforms and appetite functions. All are regulated by the Lung which controls expelling Qi, thus ensuring the flow of Qi mechanism. Therefore, whenever treating Spleen and Stomach disorders, one should prioritize regulating Lung Qi and communicating between Heart and Kidney.
Phlegm in the human body causes the most harm. Its surge is like a tide; its decline is like the ebb. Wind, Cold, Dampness, and Dryness arise with Qi; constitution being Excess or Deficiency arises with the person. Turbid phlegm is thick; clear phlegm is thin. There is no place among the Five Zang and Six Fu organs where phlegm does not exist; its ascending and descending has no fixed time; it is incompatible with Healthy Qi, much like dark clouds and miasmic fog in heaven and earth.
Qi and Blood throughout the body are all interconnected. Thus, ancients used acupuncture to unblock the exterior, moving from outside to inside to harmonize Qi and Blood; they used herbs to unblock the interior, moving from inside to outside to harmonize Qi and Blood. The principle is the same. As for "when there is free flow, there is no pain; when there is pain, there is no free flow," this refers to the original state of free flow now becoming blocked. Whether internal or external, once one area is unblocked, pain ceases. One should unblock the Twelve Meridians and Zang-Fu organs according to their respective locations. If one unblocks other areas, the painful site remains unknown, while other areas may instead become pulled or agitated.
Tonification: beware of administering too hastily and causing sudden stagnation. Purging: beware of attacking too urgently and using harsh/drastic agents. Improper use of either can cause harm. For example, improper purging of Heat may leave Heat unresolved while Cold reappears; Cold and Heat occupy their respective positions, making both warming and cooling therapies contraindicated, leaving even good physicians at a loss. The same applies to purging Cold.
People only know that failing to store Essence in Winter leads to disease, but do not realize that failing to store Essence in Summer is even more severe. I have seen frail individuals during intense summer heat often complaining of suffocating breathlessness. Those who die from Heatstroke (Zhongshu) die directly due to this Qi blockage/suffocation. After sexual emission, people often experience shortness of breath, which is not far different from the Qi blockage in summer heat. The Classic says: "Heat injures Qi," and also: "Blazing Fire consumes Qi." Therefore, I say the blazing power of Summer exceeds the cold of Winter. If Essence is not stored, robust individuals may develop latent summerheat in Autumn, while frail individuals may die immediately from Heatstroke.