已饥先食，未饱先止。散步逍遥，务令腹空。每腹空时，即便入定。不拘昼夜，坐卧自
便。惟在摄身。使如木偶，常自念言。我今此身，若少动摇，如毛发许，便堕地狱。如商君
法，如孙武令。事在必行，有死无犯。又用佛语及老君语，视鼻端，自数出入息，绵绵若存，
用之不勤，数至数百，此心寂然，此身兀然。与虚空等，不烦禁制。自然不动，数至数千，
或不能数。则有一法，其名曰随，与息俱出，复与俱入，随之不已。一息自住，不出不入。
或觉此息，从毛窍中八万四千云蒸雾散。无始已来，诸病自除，诸障自灭。自然明悟，譬如
盲人。忽然有眼，此时何用求人指路，是故老人言尽如此。
郑子产曰，火烈者人望而畏之，水弱者人狎而玩之。翼奉论六情十二律。其论水火也，
曰北方之情好也。好行贪狠，南方之情恶也。恶行廉正，廉正故为君子，贪狠故为小人。予
参二人之学，而为之说曰∶火烈而水弱。烈生正，弱生邪。火为心，水为肾。故五脏之性，
心正而肾邪。肾无不邪者，虽上智之肾亦邪。然上智常不淫者，心之官正，而肾听命也。心
无不正者，虽下愚之心亦正。然下愚常淫者，心不官，而肾为政也。知此，则知铅汞龙虎之
说矣。何谓铅？凡气之谓铅，或趋或蹶，或呼或吸，或执或击。凡动物者皆铅。肺实出纳之，
肺为金，为白虎，故曰铅，又曰虎。何为汞？凡水皆为汞，唾 脓血，精汗便利，凡湿者皆
汞也，肝实宿藏之。肝为木，为青龙，故曰汞，又曰龙，古之真人论内丹曰∶五行颠倒术，
龙从火内出。五行不顺行，虎向水中生。世未有知其说者也。方五行之顺行也。则龙出于水，
虎出于火，皆死之道也。心不官而肾为政，声色外诱，淫邪内发，壬癸之英。下流为人，或
为腐坏，是汞龙之出于水也。喜怒哀乐皆出于心者也，喜则撄 随之，怒则殴击随之。哀则
擗踊随之，乐则 舞随之。心动于内，而气应于外，是铅虎之出于火者也。汞龙之出于水，
铅虎之出于火。有能出于火，有能出于水。而复返者乎？故曰皆死之道也。真人教之以逆行
，龙从火出，虎从水生也。其说若何？孔子曰∶思无邪。凡有思皆邪也，而无思则土木也。
孰能使有思而非邪，无思而非土木乎？盖必有无思之思焉。夫无思之思，端正庄栗，如临君
师，未尝一念放逸。然卒无所思，如龟毛兔角。非作故无，本性无故，是谓之戒。戒生定，
定则出入息自住。出入息住，则心火不复炎。在易为离，离丽也，必有所丽。未尝独立，而
汞其妃也。既不炎上，则从其妃矣。水火合，则壬癸之英。上流于脑，而溢于元英。若鼻液
而
天一为水。凡人之始造形皆水也，故五行一曰水。从暖气而后生，故二曰火。生而后有骨，
故三曰木。骨生而日坚，凡物之坚壮者，皆金气也，故四曰金。骨坚而后生肉焉，土为肉，
故五曰土。人之在母也。母呼亦呼，母吸亦吸。口鼻皆闭，而以脐达，故脐者生之根也。汞
龙之出于火，流于脑，溢于元英，必归于根。心火不炎上，必从其妃，是火常在根也。故壬
癸之英，得火而日坚，达于四肢，浃于肌肤而日壮。究其极，则金刚之体也，此铅虎之自水
出者也，龙虎生而内丹成矣，故曰顺行则为人。逆行则为道，道则末也，亦可为长生不死之
术矣。
饥饿尚未完全产生时先进食，饱足尚未达到极限时先停止。散步闲适，务必让腹部保持空虚。每当腹部空虚时，便立即进入静定状态。不分白天黑夜，坐卧随意自在。关键在于约束身心，使身体像木偶一样静止，心中常默念：我现在的这个身体，如果稍有动摇，哪怕只有毛发般细微的幅度，就会堕入地狱。要像商鞅的法度、孙武的军令那样，必须坚决执行，宁死也不违犯。同时运用佛家和老子的话语教导，注视鼻尖，自行计数呼吸的次数，气息绵绵若有若无，使用它而不宜过度用力，数到几百次，此时内心寂静，身体巍然不动，与虚空等同，不需要刻意禁止控制，自然不再动摇；数到几千次，或者无法继续计数时，就有一种方法，名叫“随”，随着气息一起呼出，又随着气息一起吸入，跟随不已。直到一次呼吸自然停住，既不出也不入。如果觉得气息从全身八万四千毛孔中如云雾般蒸腾发散，那么从无始以来所有的疾病自然消除，所有的障碍自然灭尽。自然获得明悟，就像盲人忽然复明，这时哪里还需要别人指引道路？所以老人说尽在于此。
郑子产说：火势猛烈，人们望而生畏；水性柔弱，人们亲近而玩弄。翼奉论述六情与十二律。他论及水火时说：北方的情感是“好”（喜爱）。“好”表现为贪婪狠毒；南方的情感是“恶”（厌恶）。“恶”表现为廉洁正直。因为廉洁正直所以成为君子，因为贪婪狠毒所以成为小人。我参究这两人的学说，并为他们解说：火性猛烈而水性柔弱。猛烈产生正直，柔弱产生邪僻。火对应心，水对应肾。所以五脏的本性，心是正直的而肾是邪僻的。肾没有不邪僻的，即使是上智之人的肾也是邪僻的。然而上智之人常常不放纵，是因为心的功能端正，而肾听从命令。心没有不正的，即使是下愚之人的心也是正的。然而下愚之人常常放纵，是因为心不发挥职能，而肾专权执政。懂得这一点，就能理解铅汞龙虎的说法了。什么是铅？凡是气的运动称为铅，或趋向或跌倒，或呼气或吸气，或执持或击打。凡是动物都具有铅的特性。肺实际负责出纳气机，肺属金，为白虎，所以叫铅，又叫虎。什么是汞？凡是水都称为汞，唾沫、脓血、精液、汗液、大小便，凡是湿润的东西都是汞。肝实际储藏这些物质。肝属木，为青龙，所以叫汞，又叫龙。古代的真人论述内丹时说：“五行颠倒术，龙从火内出。五行不顺行，虎向水中生。”世上没有人能懂其中的道理。当五行顺行时，龙出于水，虎出于火，这都是死亡的道路。心不发挥职能而肾专权执政，声色在外诱惑，淫邪在内发作，壬癸（水）的精微向下流溢为人，或者导致腐坏，这是汞龙出于水的表现。喜怒哀乐都发于心，喜悦则随之扰动，愤怒则随之殴击，悲哀则随之捶胸顿足，快乐则随之舞蹈。心动于内，而气应于外，这是铅虎出于火的表現。汞龙出于水，铅虎出于火。如果有人能从火中出来，从水中出来，然后再返回本源吗？所以说这都是死亡的道路。真人教导人们逆向而行，龙从火出，虎从水生。其道理是什么？孔子说：“思无邪。”凡是有所思虑都是邪僻，但没有思虑就像土木一样死寂。谁能做到有思虑而非邪僻，无思虑而非死寂呢？大概必须有“无思之思”。这种无思之思，端正庄重，如同面对君主和老师，从未有过一念的放逸。然而最终无所思虑，如同龟毛兔角般虚无。这不是故意造作而无，而是本性原本就没有，这就叫做“戒”。戒能生定，定则呼吸自然停住。呼吸停住，则心火不再炎上。在《易经》中这对应离卦，离即附着，必定有所依附，不曾独立存在，而汞（水）是它的配偶。既然不向上炎上，就顺从其配偶。水火相合，则壬癸（水）的精微向上流入脑部，并溢出到元英（元神）。若鼻液流出，天一生成水。凡是人最初形成形体都是水，所以五行中第一是水。从暖气而后产生，所以第二是火。产生之后才有骨骼，所以第三是木。骨骼产生后日益坚硬，凡物中坚壮的都是金气，所以第四是金。骨骼坚硬之后才生出肌肉，土代表肉，所以第五是土。人在母体中时，母亲呼气他也呼气，母亲吸气他也吸气，口鼻皆闭，通过脐带连接，所以脐是生命的根本。汞龙出于火，流于脑部，溢出到元英，必然回归根本。心火不向上炎上，必然顺从其配偶，这样火就常在根本处。所以壬癸的精微，得到火的作用而日益坚硬，通达四肢，渗透肌肤而日益强壮。穷究其极致，就是金刚不坏之体，这就是铅虎从水中出来的表现。龙虎相生而内丹成就，所以说顺行则为人，逆行则为道，道虽然是末节，也可以作为长生不死的技术了。
Eat before feeling fully hungry, and stop eating before feeling fully full. Take leisurely walks, ensuring the abdomen remains empty. Whenever the abdomen is empty, immediately enter a state of meditation (Ding). This applies regardless of day or night; sitting or lying down, be at ease. The key lies in restraining the body, making it still as a wooden puppet, while constantly thinking to oneself: "This body of mine, if it moves even slightly, not even as much as a hair's breadth, will fall into hell." It must be executed with the strictness of Shang Yang's laws and Sun Wu's military orders. One must act decisively, preferring death over violation. Additionally, using words from Buddhism and Laozi, gaze at the tip of the nose, counting breaths in and out. The breath should be continuous and seemingly present yet absent, used without excessive effort. Counting up to several hundred, the mind becomes silent, and the body stands firm like a rock. Equal to the void, no need for suppression or control, it naturally remains motionless. Counting up to several thousand, or if unable to count further, there is a method called "Following" (Sui). Follow the breath as it exits, and follow it as it enters, continuing this practice. Until one breath naturally stops, neither exiting nor entering. If one feels the breath dispersing like clouds and mist through eighty-four thousand pores, then since beginningless time, all diseases are naturally eliminated, and all obstacles naturally vanish. Naturally attaining clarity and enlightenment, like a blind person suddenly gaining sight, why would one need others to point out the path? Thus, the old man says it all comes down to this.
Zheng Zichan said: "Fire is fierce, so people fear it; water is weak, so people play with it." Yi Feng discussed the Six Emotions and Twelve Pitch-pipes. In his discussion on water and fire, he stated: "The emotion of the North is 'Hao' (Love/Desire). Hao leads to greed and cruelty. The emotion of the South is 'E' (Hatred/Aversion). E leads to integrity and righteousness. Because of integrity and righteousness, one becomes a gentleman; because of greed and cruelty, one becomes a petty person." I have studied both their teachings and offer an explanation: Fire is fierce, Water is weak. Fierceness generates righteousness, weakness generates evil. Fire corresponds to the Heart, Water to the Kidney. Therefore, among the Five Viscera, the Heart is righteous, and the Kidney is evil. The Kidney is never free from evil; even the Kidney of the supremely wise is evil. However, the supremely wise do not indulge because the function of the Heart is upright, and the Kidney obeys its command. The Heart is never unrighteous; even the Heart of the utterly foolish is upright. Yet the utterly foolish indulge because the Heart does not exercise its function, and the Kidney takes charge. Understanding this, one can understand the theories of Lead (Qian), Mercury (Gong), Dragon, and Tiger. What is Lead? Any movement of Qi is called Lead, whether advancing or retreating, exhaling or inhaling, grasping or striking. All animals possess Lead. The Lung actually manages the intake and output of Qi. The Lung belongs to Metal and represents the White Tiger, hence it is called Lead, also known as Tiger. What is Mercury? Any fluid is called Mercury, including saliva, pus, blood, essence, sweat, urine, and feces; anything moist is Mercury. The Liver actually stores these substances. The Liver belongs to Wood and represents the Green Dragon, hence it is called Mercury, also known as Dragon. Ancient perfected beings discussing Internal Alchemy said: "The art of reversing the Five Elements: The Dragon emerges from within Fire. The Five Elements do not proceed in order; the Tiger is born from within Water." No one in the world understands this theory. When the Five Elements proceed in their natural order, the Dragon emerges from Water, and the Tiger from Fire; this is the path of death. When the Heart does not exercise its function and the Kidney takes charge, external seduction by sounds and colors triggers internal emission of lust and evil. The essence of Ren and Gui (Water) flows downward into humanity, leading to decay; this is Mercury and the Dragon emerging from Water. Joy, anger, sorrow, and happiness all originate from the Heart. Joy brings disturbance, anger brings beating, sorrow brings wailing, and happiness brings dancing. The Heart moves internally, and Qi responds externally; this is Lead and the Tiger emerging from Fire. Mercury and the Dragon emerge from Water; Lead and the Tiger emerge from Fire. Can anyone emerge from Fire, emerge from Water, and then return? Thus, it is said that this is the path of death. Perfected beings teach reverse practice: the Dragon emerges from Fire, and the Tiger from Water. What is the reasoning? Confucius said: "Let thoughts be without evil." Any thought is considered evil, but no thought makes one like wood or stone. Who can make thoughts non-evil while having them, and non-stagnant while having none? There must be a "thought of no-thought." This thought of no-thought is upright and solemn, as if facing a ruler or teacher, never allowing a single moment of laxity. Yet ultimately, there is nothing to think of, like turtle hair or rabbit horns. This is not artificially created emptiness, but the original nature being empty; this is called Precepts (Jie). Precepts generate Concentration (Ding); when concentrated, breathing naturally stops. When breathing stops, Heart Fire no longer flares upward. In the *I Ching*, this corresponds to the Li Trigram. Li means adhering; it must adhere to something and never stands alone. Mercury (Water) is its consort. Since it does not flare upward, it follows its consort. When Water and Fire combine, the essence of Ren and Gui flows upward into the brain and overflows into the Primordial Essence. If nasal fluid flows, Tianyi generates Water. Human form initially originates from Water, so Water is the first of the Five Elements. From warm air arises Fire, so Fire is second. After birth, bones form, so Wood is third. Bones become hard; hardness and strength belong to Metal, so Metal is fourth. After bones are hard, flesh grows; Earth represents flesh, so Earth is fifth. While in the womb, the infant breathes when the mother breathes in and out, with mouth and nose closed, connected via the umbilicus. Thus, the umbilicus is the root of life. Mercury and the Dragon emerge from Fire, flow to the brain, overflow into the Primordial Essence, and must return to the root. Heart Fire does not flare upward but follows its consort, so Fire resides at the root. Thus, the essence of Ren and Gui, empowered by Fire, becomes increasingly hard, reaching the limbs and permeating the skin and muscles, becoming stronger daily. At its extreme, it forms a Diamond Body. This is Lead and the Tiger emerging from Water. When Dragon and Tiger generate each other, Internal Alchemy is achieved. Thus, proceeding forward leads to human existence; reversing leads to the Dao. Although Dao is the end, it can also serve as the technique for immortality.