夫身之内，不过阴阳为之根蒂。医者惟明此二字，病之吉凶，莫不判然矣。故凡伤寒危迫，手
脉难明，须察足脉，不知者竞相哗笑，更有内室，宁死不愿，以为羞耻，是又大可哀矣。予请陈
其说焉。经曰∶“治病必求于本。”本之为言根也、源也。世未有无源之流，无根之木。澄其源而
流自清，灌其根而枝乃茂，自然之经也。故善为医者，必责根本，而本有先天后天之辨。先天
之本维何，足少阴肾是也。肾应北方之水，水为天一之源。后天之本维何，足阳明胃是也。胃
应中宫之土，土为万物之母。肾何以为先天之本？盖婴儿未成，先结胞胎，其象中空，一茎透
起，形如莲蕊；一茎即脐带，莲蕊即两肾也，而命寓焉。水生木而后肝成，木生火而后心成，火
生土而后脾成，土生金而后肺成。五脏既生，六腑随之，四肢乃具，百骸乃全。仙经曰∶“借问
如何是玄牝，婴儿初生先两肾。”故肾为脏腑之本，十二脉之根呼吸之本，三焦之源，而人
资之以为始者也。故曰，先天之本在肾。而太 一穴，在足内踝后五分跟骨上动脉陷中，此
足少阴所注为 之地也。脾胃何以为后天之本？盖婴儿既生，一日不再食则饥，七日不食
则肠胃涸绝而死。经曰∶“安谷则昌绝谷则亡。”犹兵家之有饷道也。饷道一绝，万众立散；胃
气一败，百药难施。一有此身，先资谷气。谷入于胃，洒陈于六腑而气至，和调于五脏而血生，
而人资之以为生者也。故曰，后天之本在脾。而冲阳一穴，在足跗上五寸高骨间动脉去陷
谷二寸，此足阳明所过为原之地也。（脾胃相为夫妇，故列胃之动脉，而脾即在其中矣。）古人见肾为先天之本，故着之
脉曰∶“人之有尺，犹树之有根，枝叶虽枯槁，根本将自生。”见脾胃为后天之本，故着之脉曰∶“有
胃气则生，无胃气则死。”所以伤寒必诊太 以察肾气之盛衰，必诊冲阳以察胃气之有
无。两脉既在，他脉可勿问也。如妇人则又独重太冲者，太冲应肝，在足指本节后二寸陷中。
盖肝者，东方木也，生物之始；又妇人主血，而肝为血海，此脉不衰，则生生之机犹可望也。予
见按手而不及足者多矣，将欲拯人于危，殆盖亦少探本之学乎！
在人体内部，不过是阴阳作为根本。医生只要明白这两个字，疾病的吉凶，就没有不分辨清楚的。所以凡是伤寒病情危急紧迫，手腕部的脉象难以辨明时，必须诊察足部的脉象。不知道的人竞相嘲笑，更有身处内室（指女性患者）的，宁愿死也不愿让人诊察，认为这是羞耻之事，这更是大可悲哀的了。我请求陈述其中的道理。医经说：“治病必须探求根本。”“本”这个字的意思就是根、源。世上没有无源的流水，也没有无根的树木。澄清源头而水流自然清澈，浇灌树根而枝叶才能茂盛，这是自然的规律。所以善于行医的人，必定追究根本，而根本有先天和后天的区别。先天的根本是什么？是足少阴肾经。肾对应北方的水，水是天一之源。后天的根本是什么？是足阳明胃经。胃对应中宫的土，土是万物的母亲。肾为什么是先天之本？大概婴儿尚未形成时，先结成胞胎，它的形象中空，有一茎突起，形状像莲花的蕊；这一茎就是脐带，莲花的蕊就是两肾，而命门寓居其中。水生木而后肝形成，木生火而后心形成，火生土而后脾形成，土生金而后肺形成。五脏既已生成，六腑随之而成，四肢才具备，百骸才完整。仙经说：“借问什么是玄牝，婴儿初生先有两肾。”所以肾是脏腑的根本，十二经脉的根源，呼吸的根本，三焦的源头，而人依靠它作为生命的开始。所以说，先天之本在肾。而太溪穴，位于足内踝后方五分处的跟骨上动脉凹陷中，这是足少阴肾经所注为腧的地方。（注：原文“太 一穴”及“太 ”根据上下文及中医常识应为“太溪”，此处依文意翻译为太溪穴）。脾胃为什么是后天之本？大概婴儿出生后，一天不吃东西就会饥饿，七天不吃东西肠胃就会干枯断绝而死。医经说：“能进食则昌盛，不能进食则灭亡。”就像军队中有粮道一样。粮道一旦断绝，万众立刻溃散；胃气一旦败坏，各种药物都难以施用。有了这个身体，首先依赖谷气。谷物进入胃中，散布于六腑而气至，调和于五脏而血生，而人依靠它来维持生命。所以说，后天之本在脾。而冲阳穴，位于足背上方五寸高骨间的动脉处，距离陷谷穴二寸，这是足阳明胃经所过为原的地方。（脾胃互为夫妇关系，所以列出胃的动脉，而脾就在其中了。）古人看到肾是先天之本，所以在脉学中记载：“人的尺部脉，就像树的根，枝叶虽然枯槁，根本将自行生长。”看到脾胃是后天之本，所以在脉学中记载：“有胃气则生，无胃气则死。”所以伤寒病必须诊察太溪以观察肾气的盛衰，必须诊察冲阳以观察胃气的有无。这两条脉既然存在，其他脉象就可以不必问了。如果是妇女，则又特别重视太冲脉，太冲对应肝脏，位于足趾本节后方二寸的凹陷中。大概肝是东方的木，是生物的开始；又因为妇女主血，而肝为血海，这条脉不衰败，那么生生不息的生机还抱有希望。我见到按诊手部脉象而不诊察足部脉象的情况很多了，想要拯救处于危难中的人，恐怕也是很少探究探求根本的学问吧！
Within the human body, Yin and Yang serve as the root and foundation. If a physician clearly understands these two concepts, the auspicious or inauspicious nature of any disease can be readily discerned. Therefore, when treating severe cases of Shanghan (Cold Damage) where the pulse at the wrist is difficult to clarify, it is necessary to examine the pulses at the feet. Those who are ignorant often mock this practice. Furthermore, for patients confined to inner chambers (referring to women), they may prefer death over allowing such an examination, considering it shameful; this is truly lamentable. I would like to expound on this theory. The Classic states: "In treating diseases, one must seek the root." The term "root" implies origin and source. There are no streams without sources, nor trees without roots. Clearing the source makes the stream flow clear naturally; watering the root causes the branches and leaves to flourish naturally. Thus, skilled physicians always investigate the root. However, the root has distinctions between Xiantian (Pre-heaven/Innate) and Hou Tian (Post-heaven/Acquired). What constitutes the Pre-heaven root? It is the Foot Shaoyin Kidney Meridian. The Kidney corresponds to Water in the North, which is the source of Heavenly One. What constitutes the Post-heaven root? It is the Foot Yangming Stomach Meridian. The Stomach corresponds to Earth in the Central Palace, which is the mother of all things. Why is the Kidney the Pre-heaven root? When an embryo has not yet formed, the placenta first coalesces; its form is hollow in the center with a stalk protruding, resembling the pistil of a lotus. This stalk is the umbilical cord, and the lotus pistil represents the two kidneys, where the Mingmen (Gate of Life) resides. Water generates Wood, then the Liver forms; Wood generates Fire, then the Heart forms; Fire generates Earth, then the Spleen forms; Earth generates Metal, then the Lungs form. Once the Five Zang Organs are generated, the Six Fu Organs follow, the four limbs are equipped, and the entire skeleton is complete. The Daoist Canon says: "Ask what is the Xuanpin (Mysterious Female); it is the two kidneys present when the infant is first born." Therefore, the Kidney is the root of the Zang-Fu organs, the root of the Twelve Meridians, the root of respiration, and the source of the Sanjiao (Triple Burner), serving as the beginning of human endowment. Hence, it is said that the Pre-heaven root lies in the Kidney. The Taixi Acupoint (Taixi, KI3) is located five fen behind the medial malleolus, in the depression of the arterial pulse on the calcaneus. This is where the Foot Shaoyin Meridian pours into its Shu-Stream point. Why are the Spleen and Stomach the Post-heaven root? After birth, if an infant does not eat for one day, hunger ensues; if they do not eat for seven days, the intestines and stomach dry up and death occurs. The Classic states: "Abundance of grain leads to prosperity; absence of grain leads to demise." This is akin to the supply lines in military strategy. If the supply line is cut, the army scatters instantly; if the Stomach Qi fails, even myriad medicines become useless. Upon having a body, one first relies on Gu Qi (Grain Qi). Grain enters the Stomach, spreads through the Six Fu Organs so that Qi arrives, and harmonizes within the Five Zang Organs so that Blood is generated. Humans rely on this for life. Hence, it is said that the Post-heaven root lies in the Spleen and Stomach. The Chongyang Acupoint (Chongyang, ST42) is located five cun above the dorsum of the foot, between the high bones, in the arterial pulse, two cun away from the Xiangu Acupoint (Xiangu, ST43). This is where the Foot Yangming Meridian passes through its Yuan-Source point. (The Spleen and Stomach are mutually related like husband and wife; thus, listing the Stomach's artery implies the Spleen is included therein.) Ancient masters observed that the Kidney is the Pre-heaven root, hence recording in pulse diagnosis: "A person's Chi position pulse is like the root of a tree; although the branches and leaves may wither, the root will regenerate." Observing that the Spleen and Stomach are the Post-heaven root, they recorded: "With Stomach Qi, there is life; without Stomach Qi, there is death." Therefore, in Shanghan, one must palpate Taixi to observe the flourishing or decline of Kidney Qi, and Chongyang to observe the presence or absence of Stomach Qi. If these two pulses are present, other pulses need not be questioned. For women, however, particular emphasis is placed on the Taichong pulse. Taichong corresponds to the Liver and is located two cun posterior to the metatarsophalangeal joint of the big toe, in the depression. The Liver belongs to Wood in the East, representing the beginning of biological generation. Moreover, women govern Blood, and the Liver is the Sea of Blood. As long as this pulse remains vigorous, the mechanism of continuous life generation can still be hoped for. I have seen many instances where practitioners palpate the hand but neglect the feet. To save people from danger, is it not because they rarely explore the learning of seeking the root?