夫炼精化气，乃逆行法也。欲知仙凡之隔，当知顺逆之分。经曰∶顺则成人，逆则成仙是也
。顺行则致一身之气化而为精，是以阳变阴，乃成人之道也。凡人有所感触而兴起者，或交感忍而
不泄，或梦觉交而未遗，犯此者，精虽未∶泄，然念头驰动，而流珠便欲去人，其精己离各脏腑，
奔出于肾，凝聚于阴跷、会阴等处矣。由是其精有从溺出者，有结为悬痈者，有闭其窍溺不通者，
有变为赤白浊者，有变为淋沥者，有致遗精不禁者，有凝结为痔漏者，有积久不泄，遂致一溃倾命
者，种种遗患，难以尽举。仙翁所以怜悯世人，立此炼精化气之法；以却其病，以延其年，非大有
福缘者，不能遇此。须要知其聚精当为何时，及其炼精为何功耳。如前云感触兴起、交媾不泄、梦
交未遗者，非所谓聚精之时耶？此时能根据法行炼精化气法十余转，则运所聚之精悉化为气，又何有
疾患哉？久久行时，则能使精元完固而可无
漏矣。此炼精化气之法，人实难明其义。譬精犹水泽也，能以法运精使升，不犹地气腾其水泽
为云雾乎？气升作甘津降下中黄，不犹云腾化作甘津以敷九野乎？精出于肾，止聚于一处，到
此复上泥丸，降下中黄，则散于一身四大矣，《易》所谓黄中通理是也。诀曰∶平气定其息，
以手握龙身，鼻息用力提，龙神往上奔，神龙归大海，阴跷上暂停，自南转北去，须臾到命门，
驾起我白驹，挽着辘轳行，夹脊三关过，曹溪上太清，兴云布甘雨，阵阵落黄庭，行此运气法
，百病
不来侵。炼士请细玩之，乃有得也。
炼精化气，属于逆行的修炼方法。想要了解仙人与凡人的区别，应当明白顺行与逆行的分别。经典说：顺行则成为人，逆行则成就仙道，正是这个意思。
顺行则是导致一身之气转化为精的过程，这是阳气变化为阴气的过程，也就是人类繁衍的自然规律。凡人受到外界事物的感触而产生性欲冲动时，有的通过交合忍耐而不泄精，有的在梦中交合醒来后没有遗精。触犯这种情况的人，虽然精液没有排出体外，但意念已经驰动，体内的“流珠”（指精气）便欲离开身体，此时精气已经脱离各脏腑，奔涌而出到达肾脏，并凝聚在阴跷脉、会阴穴等处。
因此，这些精气有的随尿液排出，有的凝结成悬痈（一种生于会阴部的脓肿），有的闭塞窍道导致小便不通，有的变为赤白浊（尿道分泌物异常），有的变为淋沥（排尿不畅、点滴而出），有的导致遗精无法控制，有的凝结成痔疮和瘘管，有的因积聚日久不泄，最终导致一次溃决而丧命。种种遗留的祸患，难以一一列举。
仙翁之所以怜悯世人，创立了这种炼精化气的方法；以此来祛除疾病，延长寿命。这不是有大福分缘分的人，不能遇到这种方法。必须知道聚集精气应当在什么时候，以及炼化精气需要做什么功夫。
正如前面所说，受到感触兴起、性交不泄、梦中交合未遗精的情况，不就是所谓的“聚精之时”吗？在这个时候如果能依据法则进行炼精化气的功法练习十余个循环，那么所聚集的精气就会全部转化为气，哪里还会有疾病呢？长久地练习，就能使精元完善坚固而没有漏失。
这种炼精化气的方法，人们实在很难明白其中的义理。譬如精气就像水泽一样，能够用功法引导精气上升，不就像地气蒸腾水泽化为云雾吗？气上升化作甘津（唾液/体液）下降至中黄庭，不就像云雾升腾化作甘霖滋润大地吗？精气出于肾脏，原本只聚集在一处，到了这里又上升到泥丸宫，再下降至中黄庭，于是分散到全身四肢百骸，《易经》所说的“黄中通理”就是这个道理。
口诀说：平定气息以稳定呼吸，用手握住龙身（指丹田或生殖器区域），鼻息用力提起，龙神（精气）向上奔腾，神龙回归大海（指下丹田或肾），在阴跷脉上暂时停留，从南转北而去，片刻到达命门，驾驭我的白驹（指真气），拉着辘轳（指脊柱通道）运行，穿过夹脊三关，沿着曹溪（指督脉或脊柱）上达太清，兴起云雾布下甘雨，阵阵落在黄庭（中指腹部）。练习这种运气法，百病就不会来侵扰。修炼之士请仔细玩味它，自然会有所得。
Refining Jing (Essence) into Qi (Vital Energy) is a method of reverse operation. To understand the separation between immortals and mortals, one must know the distinction between forward and reverse operations. The classics state: "Forward leads to becoming human; reverse leads to becoming immortal." This is precisely what it means.
Forward operation results in the transformation of the body's Qi into Jing, which is the process where Yang transforms into Yin; this is the way of human reproduction. When ordinary people are stimulated by external contacts and arousal arises, some may engage in sexual intercourse but restrain themselves from ejaculation, or experience nocturnal emissions without actual loss upon waking. For those who fall into such situations, although the Jing has not been physically discharged, the mind's thoughts have wandered, causing the "flowing pearl" (a metaphor for vital essence) to desire leaving the body. At this point, the Jing has already departed from the various Zang-Fu organs, rushing out to the Kidneys, and condensing at areas such as the Yinqiao Vessel (Yin Qiao Mai) and Huiyin (CV-8).
Consequently, this Jing may be expelled through urine, condense into a perineal abscess (Xuan Yong), block the orifices leading to urinary retention, transform into red and white turbidity (abnormal urethral discharge), become dysuria (scanty and painful urination), cause uncontrollable seminal emission, condense into hemorrhoids and fistulas, or due to long-term accumulation without release, eventually lead to a single rupture that costs one's life. Various such lingering disasters are too numerous to list.
The Immortal Patriarch, out of compassion for the world, established this method of refining Jing into Qi; to eliminate diseases and prolong life. Only those with great fortune and affinity can encounter this. One must know when to gather Jing and what efforts are required to refine it. As mentioned previously, situations involving stimulation-induced arousal, coitus without ejaculation, and nocturnal dreams without emission—are these not the so-called "times of gathering Jing"? If at this time one practices the method of refining Jing into Qi for more than ten cycles according to the rules, then all the gathered Jing will be transformed into Qi. How could there still be diseases? With long-term practice, one can make the primordial Jing complete and solid, thereby preventing leakage.
This method of refining Jing into Qi is truly difficult for people to comprehend. Imagine Jing as water pools; using methods to guide Jing upward is no different from earth vapor rising from water pools to form clouds and mist. When Qi rises and transforms into sweet saliva/fluids descending to the Middle Yellow Court, is it not like clouds rising and transforming into sweet rain to nourish the nine fields? Jing originates from the Kidneys and gathers in one place; here it ascends again to the Niwan Palace (upper Dantian), then descends to the Middle Yellow Court, dispersing throughout the four limbs and body. This corresponds to what the *I Ching* calls "Yellow in the center, penetrating the principles."
The verse states:
"Calm the Qi and stabilize the breath,
Hold the Dragon's body with hands.
Lift force with nasal breathing,
The Dragon Spirit rushes upward.
The Divine Dragon returns to the Great Sea,
Temporarily pausing at the Yinqiao.
Turning from South to North,
In an instant reaching the Mingmen.
Driving my White Steed,
Pulling the windlass along.
Passing the Three Passes of the Jiaji,
Ascending Caoxi to the Supreme Purity.
Raising clouds to distribute sweet rain,
Falling in gusts upon the Huangting.
Practicing this Qi-moving method,
Hundred diseases will not invade."
Cultivators should carefully ponder this verse, and you will surely gain something.