凡人有所以生。而非形也。形有所以促。而非病也。病有所以治。而非药石也。中医以药石治病。上医借药
石以治生。病病者不受不生。惟生生者病而生危。甚则促。故欲治生者原生。夫人何以生。生于火也。三统之说。
人生于寅。寅生火也。火阳之体也。造化以阳为生之根。人生以火为生之门。儒者曰。天开于子。水为元。医者曰。人
生于水。肾为元。孰知子为阳初也。又孰知肾为火藏也。阴生于阳。故水与火为对。然而火不与水为对体。其与水
对者。后天之火。离火也。其不与水为对者。先天之火。干火也。夫干、阳之纯也。夫阳、火之主也。夫水、火之原也。
后天之火有形。而先天者无形。有形之火。水之所克。无形之火。水之所生。今夫艾台见日而火。方诸见月而水。
此水火之大分也。然取水者迎月之光。而不迎其魄。何也。魄阴也。而光借于日则阳也。水不生于水。而生于火
明矣。是故土蒸而润。肤燠而泽。酿醅而溢。釜炊而汗。丹砂硫黄之所韫而汤也。汇为温泉出焉。水之生于火也
益信。火生乎水。亦还藏于水也。其象在坎。一阳陷于二阴之中。而命门立焉。盖火也而肾水寄之矣。其生乎水也。
其象在干。纯阳立于杂卦之先。左旋而坎水出焉。右旋而兑水纳焉。盖水也而阴阳之火。则分而寄之矣。此所谓后
天中之先天也。有气而未始有形也。无形之火以阳生。阳寄位于心则为君。神明以官。譬若火之光。以阳生阴。寄运于
三焦则为相。腑脏以充。譬若火之焰。君火在上。而相火巽乎水而上行。譬若辘轳之转而未始停也。水乃升而火降。
所谓既济者也。如是则生全。不则其生非者。反以克木。水为火所克。则水竭而
无所与藏。还以自克而生害。故养生莫先于养火。医巫闾子曰。
余所重先天之火者。非第火也。人之所以立命也。仙炼之为丹。释传之为灯。儒明之为德者。皆是物也。一以贯之也。
故命其名曰医贯。其说具载于书余不论。论其原生之大指若此。医巫闾子姓赵氏。名献可。别号养葵。其为今称。
盖有逃名之意焉。且以书成于幽州。若曰藏诸山以俟其人。刻而行之者。家伯兄司马公也。
赐进士第奉训大夫右春坊右谕德兼翰林院侍讲撰述
诰敕东宫日讲官甬东友人薛三省拜撰
大凡人有赖以生存的根本，但这根本并非形体本身。形体的早衰，原因也不在于疾病。疾病的治愈，关键也不仅仅在于药物。中医通过药物来治疗疾病，而上医则借助药物来调养生命。那些只关注治病的人，无法获得真正的生机；只有注重养生的人，才能避免生病甚至危险，从而延缓衰老。所以，想要治理生命，首要任务是养护生命的本源。人为什么能生存？是因为火。关于“三统”的说法，人生于寅位，寅对应火。火是阳的实体。造化以阳作为生命的根基，人以火作为生命的门户。儒家说：天开于子时，水为元始。医者说：人源于水，肾为元始。但谁知道子时也是阳气初生之时呢？又有谁知道肾中藏有真火呢？阴生于阳，所以水和火是对应的。然而，火并不与水构成对立的实体。真正与水相对的是后天的火，即离火（心火）。不与水相对的，是先天之火，即乾火（命门之火）。乾，是纯阳。阳，是火的主宰。水，是火的源头。后天的火是有形的，而先天的火是无形的。有形的火，是被水所克制的；无形的火，是由水所滋生的。如今，艾绒对着太阳就能生火，方诸（古代取露器）对着月亮就能生水，这是水火的大致区别。但是取水的人，迎接的是月光，而不是月亮的阴魄。为什么呢？因为魄属阴，而光借自太阳，所以属阳。水不是从水中产生的，而是从火中产生的，这已经很明白了。因此，大地受热蒸腾而湿润，皮肤温暖而有光泽，酒酿发酵而溢出，锅灶炊煮而出汗，丹砂硫黄蕴藏其中化为汤液，汇聚成温泉涌出。水由火产生，这一点更加令人信服。火生于水中，也还藏于水中。其卦象在坎卦，一阳爻陷于二阴爻之中，命门便立于此。可以说，火存在于肾水中。它生于水，其卦象在乾卦，纯阳立于杂卦之前，向左旋转则生出坎水，向右旋转则兑水纳入其中。可以说，水存在，而阴阳之火分别寄寓其中。这就是所谓的“后天中的先天”，只有气而没有形体。无形的火以阳而生，阳气寄居在心位就成为君火，主宰神明，就像火的光亮；以阳生阴，运化于三焦就成为相火，充实脏腑，就像火的火焰。君火在上，相火随着巽风在水上运行上升，就像辘轳转动而不停止。于是水上升而火下降，这就叫作“既济”（水火既济）。这样生命就能保全，否则生命就会失常，反而去克制木。如果水被火克制，那么水枯竭就无法藏精，最终反过来伤害自身。所以养生没有比养火更重要的了。医巫闾子说：
我所重视的先天之火，不仅仅是火，而是人赖以确立生命的根本。仙人修炼它成为金丹，佛教传承它成为明灯，儒家阐明它成为德行，这些都是同一个事物，用一个道理贯穿始终。所以我给这本书命名为《医贯》。其中的学说详细记载在书中，我不再赘述。这里只论述养护生命的主要宗旨如此。医巫闾子姓赵，名献可，别号养葵。他现在的称呼，大概有逃避名声的意思。而且这本书完成于幽州，意思是把它藏在山里等待合适的人。刻印并推行此书的是我的长兄司马公。
赐进士出身、奉训大夫、右春坊右谕德兼翰林院侍讲撰述、诰敕东宫日讲官、甬东友人薛三省 拜撰
Translation of the Preface to *Yi Guan* by Yi Wu Lv Zi
All human beings possess a fundamental basis for life, which is not merely the physical form. The premature decline of the form is not caused by disease. The cure of disease does not lie solely in medicine and stone (herbal remedies). Traditional Chinese Medicine treats diseases with herbs and minerals, whereas the Superior Physician utilizes herbs and minerals to nurture life. Those who focus only on treating illness cannot attain true vitality; only those who prioritize nurturing life can avoid illness and peril, thereby preventing premature decline. Therefore, to govern life, one must first nourish the origin of life. Why do humans live? It is due to Fire. According to the theory of the "Three Unities," humans are born at Yin (the third earthly branch), and Yin corresponds to Fire. Fire is the substance of Yang. Creation takes Yang as the root of life, and humans take Fire as the gateway to life. Confucians say: Heaven opened at Zi (the first earthly branch), where Water is the primal origin. Physicians say: Humans originate from Water, with the Kidney being the primal origin. But who knows that Zi is also the initial stage of Yang? And who knows that the Kidney houses True Fire? Yin is born from Yang; thus, Water and Fire are counterparts. However, Fire does not constitute an opposite entity to Water. What stands opposite to Water is Post-Heaven Fire, specifically Li Fire (Heart Fire). What does not stand opposite to Water is Pre-Heaven Fire, specifically Qian Fire (Mingmen Fire). Qian represents pure Yang. Yang is the master of Fire. Water is the source of Fire. Post-Heaven Fire has form, while Pre-Heaven Fire is formless. Formless fire is controlled by Water, but Pre-Heaven Fire is generated by Water. Consider that mugwort catches fire when exposed to the sun, while Fangzhu (an ancient vessel for collecting dew) produces water when exposed to the moon; this illustrates the major distinction between Water and Fire. Yet, those who collect water welcome the moonlight, not the moon's shadow (Po). Why? Because Po is Yin, while light borrows from the Sun, making it Yang. Thus, Water is not born from Water, but from Fire, which is clear. Consequently, earth steams and becomes moist, skin feels warm and lustrous, wine ferments and overflows, pots sweat during cooking, and cinnabar and sulfur transform into liquid within heat, gathering to emerge as hot springs. That Water is born from Fire is further confirmed. Fire arises from Water and also resides within Water. Its image is found in the Kan hexagram, where one Yang line lies trapped between two Yin lines, establishing the Mingmen. Thus, Fire resides within Kidney Water. Its generation from Water is represented by the Qian hexagram, where pure Yang stands before the miscellaneous hexagrams; rotating left generates Kan Water, and rotating right accepts Dui Water. Thus, Water exists, and the Fire of Yin and Yang is distributed and housed within it. This is referred to as "Pre-Heaven within Post-Heaven," possessing Qi but no form. Formless Fire generates through Yang; when Yang resides in the Heart, it becomes Sovereign Fire (Jun Huo), governing the Spirit (Shen Ming), akin to the brightness of fire. When Yang generates Yin and operates through the San Jiao (Triple Burner), it becomes Ministerial Fire (Xiang Huo), filling the Fu and Zang organs, akin to the flame of fire. Sovereign Fire is above, while Ministerial Fire ascends along with Xun Wind upon Water, like a windlass turning without cease. Thus, Water ascends and Fire descends, known as "Ji Ji" (Completion/After Completion). In this state, life is preserved; otherwise, life becomes abnormal, potentially counteracting Wood. If Water is controlled by Fire, Water dries up and loses its ability to store Essence, eventually harming itself. Therefore, in health preservation, nothing is more important than nourishing Fire. Yi Wu Lv Zi said:
What I emphasize regarding Pre-Heaven Fire is not merely Fire, but the foundation upon which humans establish their destiny. Immortals refine it into Elixir (Dan), Buddhists transmit it as a Lamp, and Confucians clarify it as Virtue (De); all refer to the same entity, unified by a single principle. Hence, I named this book *Yi Guan* (The Continuity of Medicine). The theories are detailed within the book, so I will not elaborate here. I discuss only the main principles of nurturing life as such. Yi Wu Lv Zi's surname is Zhao, given name Xianke, pseudonym Yangkui. His current title likely reflects an intention to avoid fame. Moreover, as the book was completed in Youzhou, it implies hiding it in the mountains awaiting the worthy person. The one who engraved and circulated it was my elder brother, Sima Gong.
Zuo San Sheng (Xue Sansheng), friend from Yongdong, who received the Jinshi degree, held the rank of Fxun Dafu, Right Admonisher of the Right Spring Pavilion, Concurrent Lecturer and Historian of the Hanlin Academy, and Daily Lecturer for the Crown Prince, respectfully composed this preface.