罗东逸曰∶刘守真尝为《脉原》，以脉行同五脏四时之迁流，不知《内经》已极详矣。而原脉之所
以，则仍未之讲也。夫脉为人之神，气血之本，而见于营之行。营之行，其根原
有二∶一出于中焦之谷神，化精液以输肺，肺主治节，以施隧道，故营血之能通流，实胃气为之充彻，
此脉之本于胃气也；一起于太冲，出少阴肾，下汇血海于厥阴，上发真阳于太阳，此太冲之精气，能灌溉
十二经，皆得于阳明胃之盛气同驻中焦，共为宗气，与营俱行于十二经，而备五十营。故脉至五十营，则
先后天之气合，而五脏之真备矣，以是上朝于肺，肺统行之，会于太渊。故曰∶气口成寸，以决生死。决
死生者，以气口能显胃气，形藏真，占四时，度六部。而有诸中者，必形于外，无差忒，此脉之所以为人
之神也。
《内经》论脉，必自下而起，推始以季胁，以次附上，定其部伍。自肘中曲池，量至神门，得一尺为
尺。自尺至寸，得一寸为寸。其诊先尺后寸，先阴后阳者，以人阴阳皆起于足下，五脏之气会于章门，
章门在季胁之次，脉从三阴起，足三阳而上之，先会于此，故《内经》诏人以脉必自下而上也。
然诊之精微，其占亦有二∶一呼脉行三寸，一吸脉行三寸，呼吸脉行六寸，常流无间，昼夜六时，而
为五十营，此以流行者占之也。五十动不一代，乃为生人之太和；不及是者，脏无气，命曰狂生。狂生者，
反太和也。候法左以候左，右以候右，上以候上，下以候下，前以候前，后以候后，六部一定，候之不移，
而以五脏为占，此以部位占之也。
原其然者，肺统元气，为心血脉之相，非独能朝百脉，亦能显百脉，脉虽借以充着，其所以能充着者
，皆肺神藏真之停泓。此其中之停泓，行者居者，固有其留而为地，与人以可占者，非特一为流行而尽之也
。要其元神，能常照百脉为五脏镜，以显其纯疵；故太渊一脉，五脏全体俱现。是以上
下左右可占，六部可诊矣。
然人之阴阳，必奉天而应四时，故春弦夏钩秋毛冬石，虽
六脉各为脏主，而又有不得不听令于时也。此繇天人葆合，故人气有不离如此矣。
乃人又有平生之诊，阴阳之禀，气态各不同形，其脉亦异，如六阴六阳，以至老少肥瘦，相因脉异。
善脉者，先察其本原，次候其胃气，藏真于四时之正，乃生平老少之分，而后及其病脉，兹四诊兼之望、
闻、问，谓之七诊，而脉之道得矣。
今世以左手为人迎，此出自《难经》，叔和祖之。不知人迎者，阳明胃之本输，在结喉两傍动脉者是。
此六阳之所迎，古人于此以候六腑之阳，若以右之寸口而候之，岂人迎之所候哉？更有趺阳者，穴之动脉
在足趺三寸之间，是胃脉之下行复上，与太冲之脉合，故得先后天并符之气，会合于此，为人之根柢，死生
之诊，于是最切。故仲景法，趺阳与少阴同诊，并取以决百病。今人废之，此仲景所斥为按手不及足之
庸工也。
岐伯曰∶人一呼脉再动，一吸脉亦再动，呼吸定息，脉五动，闰以太息，命曰平人。平人者，不病也
。人一呼脉一动，一吸脉一动，曰少气。人一呼脉三动，一吸脉三动而躁，尺热曰病温，尺不热脉滑曰病风
，脉涩曰痹。人一吸脉四动以上曰死，脉绝不至曰死，乍数乍疏曰死。
一日一夜五十营，以营五脏之精，不应数者，名曰狂生。所谓五十营者，五脏皆受气。持其脉口，
数其至也，五十动不一代者，五脏皆受气；四十动一代者，一脏无气；三十动一代者，二脏无气；二十动一
代者，三脏无气；十动一代者，四脏无气；不满十动一代，五脏无气。予之短期，要在终始。所谓五十动而不
一代者，以为常也，以知五脏之期。予之短期者，乍数乍疏也。
张景岳曰∶《难经》曰∶经言脉不满五十动而一止，一脏无气者，何脏也？然人吸者随阴入，呼者随
阳出，今吸不能至肾，至肝而还，故知一脏无气者，肾气先尽也。然则五脏和者，气脉长；五脏病者，气
脉短。观此，一脏无气，必先乎肾。以至二脏，三脏、四脏、五脏者，当自远而近，以次而短，则肾及肝，
由肝及脾，由脾及心，由心及肺。故凡病将危，气促似喘，仅呼吸于胸中数寸之间，盖真阴绝于下，孤
阳浮于上，此气短之极也，医于此际，尚欲平之，未有不随扑而灭者。夫人之死生由乎气，气之聚散由乎阴
，而得以苟延者，赖一线之气未绝耳。此脏气之不可不察也。
又曰∶代脉之义，自仲景、叔和，俱云动而中止，不能自还，因而复动，由是复止，寻之良久，乃复
强起为代。故后世以结、促、代并言，均目之为止脉，然岂以尽其义哉！夫缓而一止为结，数而一止为促，
其止或三或五，或七八至不等。此皆至数分明，起止有力。所主之病，有因气逆痰壅而为间阻者，有因气血
虚脱而为续断者，有因平素禀赋而脉道不流利者，此是结、促之谓也。至于代脉之辨则又不同，如宣明五气
论曰脾脉代，脏腑病形篇曰黄者其脉代，皆言脏气之常候，非谓代为止也。又平人气象曰但代无胃曰死，
乃言胃气去而真脏见，亦非谓代为止也。观此，则代本不一，各有深义。如五十动而不一代者，乃至数之代
，本篇所云是也。若脉本平匀，而忽强忽弱者，乃形体之代，即平人气象论所云是也。若
脾主四季，随时更代者，乃气候之代，宣明五气篇所云是也。凡脉无定候，更变不常，则均谓之代，但各
因其变而察其情。按本篇但言动止以诊五脏无气，未尝凿言死期。而王氏曰脉来缓而一止，一脏无气，
却后四岁春草生而死云云，恐未有一脏无气尚活四岁，二脏无气尚活三岁之理，
诊者辨之。
罗东逸说：刘守真曾经撰写《脉原》，认为脉象的运行如同五脏与四季的流转变化，却不知道《内经》对此已经阐述得非常详尽。然而对于脉象产生的根本原因，却仍未深入探讨。
脉是人的精神所在，气血的根本，并体现在营气的运行中。营气的运行，其根源有两个方面：一是源于中焦的水谷精微（谷神），转化为精液输送给肺，肺主治节功能，通过经络通道布散全身，所以营血能够通畅流动，实际上是依靠胃气的充盛贯通，这是脉象基于胃气的体现；二是起于太冲穴，出于少阴肾经，向下汇聚于血海（厥阴肝经），向上激发真阳至太阳经，太冲的精气能够灌溉十二经脉，都依赖于阳明胃的旺盛之气驻留中焦，共同形成宗气，与营气一起运行于十二经脉，完成五十次循环。因此，当脉搏跳动达到五十次循环时，先天之气与后天之气相合，五脏的真气就完备了，进而上朝于肺，由肺统率运行，汇聚于太渊穴。所以说：“气口成寸，以决生死。”判断死生的依据，是因为气口能显现胃气，反映脏腑真气的状态，占测四时变化，度量六部脉象。内在的情况必然显露于外部，没有差错，这就是脉之所以成为人精神所在的原因。
《内经》论述脉诊，必定从下部开始推究起始点，以季胁为起点，依次向上推定各部位置。从肘中的曲池穴量到神门穴，得一尺的长度称为“尺”。从尺部到寸部，得一寸的长度称为“寸”。其诊断先诊尺部后诊寸部，先阴后阳的原因，是因为人的阴阳之气都起于足下，五脏之气会聚于章门穴，章门位于季胁旁边，脉气从三阴经升起，足三阳经上行至此，先在此处会合，所以《内经》教导人们脉诊必须自下而上进行。
然而诊断的精微之处，其占断也有两个方面：一呼之间脉行三寸，一吸之间脉行三寸，一呼一吸脉行六寸，常流无间断，昼夜六个时辰，共完成五十次营周，这是根据脉气的流行来占断的。脉搏跳动五十次而没有一次歇止（代脉），乃是人体太和之气的表现；不足这个次数，说明脏腑无气，称之为“狂生”（指生命状态反常）。候脉的方法，左手候左侧，右手候右侧，上部候上部，下部候下部，前部候前面，后部候后面，六部定位确定后，候脉不移位，并以五脏作为占断依据，这是根据部位来占断的。
探究其原理，肺统摄元气，是心血脉的辅助，不仅能朝会百脉，也能显映百脉，脉虽然借以充盈附着，但其能充盈附着的根本，在于肺神藏真的停蓄深泓。这其中的停蓄深泓，有行者居者，确实有其停留的地方，给人可占断的依据，并非仅仅是流行而已。总之，元神能常照百脉，如五脏之镜，以显示其纯正或瑕疵；所以太渊一脉，五脏的整体状况全部显现。因此上下左右可占断，六部可诊断。
然而人的阴阳，必须顺应天道而应和四时，所以春脉弦、夏脉钩、秋脉毛、冬脉石，虽然六脉各自主管相应的脏，但又不得不听从时令的命令。这是因为天人合一，所以人气不离于此规律。
此外，人又有平素的脉诊，阴阳禀赋不同，气态形态各异，其脉象也不同，如六阴六阳，以至老少肥瘦，相互关联导致脉象差异。善于诊脉的人，先察其本源，其次候其胃气，观察藏真在四时中的正常状态，区分生平老少的差异，然后才涉及病脉，结合望、闻、问三诊，称为七诊，这样脉道的道理就掌握了。
现在世人将左手脉称为人迎，这出自《难经》，王叔和沿袭此说。不知道人迎穴是阳明胃经的本输穴，位于结喉两侧的动脉处。这是六阳经所迎之处，古人以此候六腑之阳，如果以右手的寸口来候之，哪里是人迎所候的部位呢？更有趺阳穴，其动脉在足背三寸之间，是胃脉下行复上，与太冲脉相合，因此得到先后天并符之气，会合于此，为人体的根基，死生的诊断，于此最为切要。所以张仲景的法度，趺阳脉与少阴脉同诊，并取用以决断百病。今人废弃不用，这是张仲景所斥责的为“按手不及足”的庸医。
岐伯说：人一呼脉跳动两次，一吸脉也跳动两次，呼吸定息之间，脉动五次，偶尔以太息补充，称为平人。平人，就是不生病的人。人一呼脉动一次，一吸脉动一次，称为少气。人一呼脉动三次，一吸脉动三次且躁急，尺部发热称为温病，尺部不热但脉滑称为风病，脉涩称为痹证。人一吸脉动四次以上称为死证，脉绝不再来称为死证，忽快忽慢称为死证。
一日一夜五十营，以滋养五脏之精，不应此数的，名为狂生。所谓五十营，是五脏都受气。持其脉口，数其跳动，五十次跳动没有一次歇止的，五脏都受气；四十次跳动歇止一次的，一脏无气；三十次跳动歇止一次的，二脏无气；二十次跳动歇止一次的，三脏无气；十次跳动歇止一次的，四脏无气；不满十次跳动就歇止一次的，五脏无气。给予其短期预后，关键在于始终。所谓五十动而不歇止，视为常态，以此知晓五脏的期限。给予短期预后的，是忽快忽慢的情况。
张景岳说：《难经》说：经文讲脉不满五十动而有一止，一脏无气，是哪一脏呢？回答是：人吸气时随阴气入内，呼气时随阳气外出，现在吸气不能到达肾，到肝就返回，所以知道一脏无气，是肾气先耗尽。既然这样，那么五脏调和，气脉长；五脏有病，气脉短。看这一点，一脏无气，必先关乎肾。至于二脏、三脏、四脏、五脏无气，应当由远及近，依次变短，即肾及肝，由肝及脾，由脾及心，由心及肺。所以凡是病危之时，气促似喘，仅在胸中数寸之间呼吸，大概是真阴绝于下，孤阳浮于上，这是气短的极致，医生在此时，还想使其平和，没有不随之灭亡的。人的死生取决于气，气的聚散取决于阴，得以苟延残喘，依赖一线之气未绝罢了。这就是脏气不可不察的原因。
又说：代脉的含义，自张仲景、王叔和以来，都说脉动而中止，不能自行恢复，因而再次跳动，由此再次停止，寻摸良久，才勉强再起为代。所以后世将结、促、代并提，都称之为止脉，但这难道能穷尽其义吗！脉缓而一止为结，脉数而一止为促，其止或三或五，或七八至不等。这些都至数分明，起止有力。其所主的病，有因气逆痰壅而为间阻者，有因气血虚脱而为续断者，有因平素禀赋而脉道不流利者，这就是结、促的意思。至于代脉的辨别则又不同，如《宣明五气论》说脾脉代，《脏腑病形篇》说黄者其脉代，都是言脏气的常候，并非谓代为停止。又《平人气象论》说但代无胃曰死，乃言胃气去而真脏见，也并非谓代为停止。看这些，则代本不一，各有深义。如五十动而不一代，是至数之代，本篇所说的是这种情况。若脉本平匀，而忽强忽弱的，是形体之代，即《平人气象论》所说的情况。若脾主四季，随时更代的，是气候之代，《宣明五气篇》所说的情况。凡脉无定候，更变不常，都称为代，但各因其变而察其情。按本篇只言动止以诊五脏无气，未曾明确说死期。而王冰注解说脉来缓而一止，一脏无气，却后四岁春草生而死云云，恐怕没有一脏无气还能活四年的道理，二脏无气还能活三年的道理，请诊者辨之。
Luo Dongyi stated: Liu Shouzhen once wrote "Mai Yuan" (Origin of Pulse), asserting that the movement of the pulse is analogous to the circulation of the Five Zang organs and the Four Seasons. However, he failed to realize that the "Nei Jing" (Inner Canon) had already elaborated on this in great detail. Furthermore, the fundamental cause of the pulse's generation remained unexplored.
The pulse is the manifestation of human spirit and the root of Qi and Blood, appearing through the movement of Ying (Nutrient) Qi. The origin of Ying Qi's movement lies in two aspects: First, it arises from the grain spirit (Gu Shen) in the Middle Jiao, which transforms into essence and fluid and transports them to the Lung. The Lung governs regulation and distributes these substances via the collaterals; thus, the smooth flow of Ying Blood actually relies on the sufficiency and penetration of Stomach Qi. This illustrates that the pulse is rooted in Stomach Qi. Second, it originates at Taichong (LR3), emerges from the Shaoyin Kidney channel, gathers downward into the Sea of Blood (Jueyin Liver channel), and ascends to stimulate True Yang to the Taiyang channel. The essence and Qi of Taichong can irrigate the Twelve Channels, all relying on the vigorous Qi of the Yangming Stomach residing in the Middle Jiao. Together, they form Zong (Gathering) Qi, moving with Ying Qi through the Twelve Channels to complete fifty cycles. Therefore, when the pulse completes fifty cycles, Pre-Heaven (Innate) Qi and Post-Heaven (Acquired) Qi combine, and the true Qi of the Five Zang organs becomes complete. It then ascends to the Lung, which directs its flow, converging at Taiyuan (LU9). Hence it is said: "The Qi Kou (Radial Artery at the wrist) forms the cun position, determining life and death." The determination of life and death depends on the fact that the Qi Kou reveals Stomach Qi, reflects the true state of the Zang organs, predicts seasonal changes, and measures the six positions. What exists internally must manifest externally without error; this is why the pulse serves as the spirit of man.
The "Nei Jing" discusses pulse diagnosis starting from the lower body, tracing back to the hypochondrium, and sequentially defining the positions. From Quchi (LI11) in the elbow to Shenmen (HT7), a distance of one chi constitutes the "Chi" (Cubit) section. From Chi to Cun (Inch), a distance of one cun constitutes the "Cun" section. Diagnosis begins with Chi before Cun, and Yin before Yang, because human Yin and Yang Qi both originate from the soles of the feet, and the Qi of the Five Zang organs converges at Zhangmen (LR13). Zhangmen is located next to the hypochondrium, where the pulse rises from the Three Yin channels and the Foot Yangming channels ascend to meet. Thus, the "Nei Jing" instructs that pulse diagnosis must proceed from bottom to top.
However, the subtlety of diagnosis involves two aspects of prediction: In one respiration cycle, the pulse moves three cun; in another, three cun; total six cun per breath cycle. Flowing continuously without interruption over six hours of day and night, it completes fifty Ying cycles. This is prediction based on continuous flow. Fifty movements without an intermittent pause (Dai Mai) indicate the supreme harmony (Taihe) of life; fewer than this indicates organ deficiency of Qi, termed "Kuang Sheng" (abnormal life state). The method of observation is: left hand for the left side, right hand for the right side, upper for upper, lower for lower, anterior for anterior, posterior for posterior. With the six positions fixed, observation remains steady, using the Five Zang as the basis for prediction. This is prediction based on anatomical position.
Investigating the principle, the Lung commands Primary Qi and assists the Heart and Blood vessels. It not only meets the hundred vessels but also reveals them. Although the pulse relies on the Lung for fullness, the reason for this fullness lies in the deep accumulation of the Lung Spirit and True Qi. Within this accumulation, there are stationary and moving elements, providing a stable ground for diagnosis, rather than mere transient flow. Ultimately, the Primordial Spirit illuminates the hundred vessels like a mirror for the Five Zang, revealing purity or defect. Thus, the single vessel at Taiyuan reveals the entire state of the Five Zang. Consequently, the upper/lower and left/right can be predicted, and the six positions diagnosed.
Human Yin and Yang must follow Heaven and respond to the Four Seasons. Thus, Spring pulses are wiry (Xian), Summer hooked (Gou), Autumn floating/hairy (Mao), and Winter stone-like (Shi). Although each of the six pulses governs a specific organ, they must obey the command of the season. This is due to the unity of Heaven and Man, hence human Qi adheres to this law.
Furthermore, individuals have their own baseline pulse diagnosis. Differences in Yin-Yang endowment, Qi dynamics, and physical form result in different pulses, such as Six Yin/Six Yang patterns, or variations due to age, obesity, and thinness. A skilled practitioner first examines the root, then observes Stomach Qi, notes the normal state of Zang True Qi across seasons, distinguishes between young/old baselines, and only then addresses pathological pulses. Combining this with Observation, Auscultation/Olfaction, and Inquiry constitutes the Seven Diagnoses, mastering the Dao of the pulse.
Currently, people refer to the left hand pulse as Renying (Human Welcome), originating from the "Nan Jing" and adopted by Wang Shuhe. They do not know that Renying is the source point of the Yangming Stomach channel, located at the arterial pulse beside the Adam's apple. This is where the Six Yang channels converge, and ancients used it to observe the Yang of the Six Fu organs. Using the Cun Kou (Radial artery) on the right to observe this would not be observing Renying. Additionally, there is Duyang (Foot Yangming), an arterial point between the foot dorsum and three cun down, where the Stomach pulse descends and ascends again, merging with the Taichong pulse. Here, Pre-Heaven and Post-Heaven Qi combine, forming the root of life and the most critical site for diagnosing life and death. Therefore, Zhang Zhongjing's method involved simultaneous diagnosis of Duyang and Shaoyin pulses to determine various diseases. Modern neglect of this practice is what Zhang Zhongjing criticized as the work of incompetent physicians who "palpate the hands but fail to reach the feet."
Qibo stated: One exhalation causes two pulse beats, one inhalation causes two beats. Between the end of exhalation and inhalation, there are five beats. Occasionally supplemented by a deep sigh, this is called a "Ping Ren" (Normal Person). A Normal Person is disease-free. If one exhalation causes one beat and one inhalation one beat, it is called "Shao Qi" (Deficient Qi). If one exhalation causes three beats and one inhalation three beats, accompanied by restlessness, heat in the Chi area indicates Warm Disease; no heat with slippery pulse indicates Wind Disease; choppy pulse indicates Bi Syndrome. If one inhalation causes four or more beats, it indicates death. Absence of pulse indicates death. Irregular rhythm (fast and slow alternation) indicates death.
Fifty Ying cycles occur in a day and night to nourish the essence of the Five Zang. Failure to reach this number is termed Kuang Sheng. Regarding the fifty cycles, all Five Zang receive Qi. Holding the pulse mouth and counting: fifty movements without a pause mean all Five Zang receive Qi; forty movements with one pause mean one Zang lacks Qi; thirty movements with one pause mean two Zang lack Qi; twenty movements with one pause mean three Zang lack Qi; ten movements with one pause mean four Zang lack Qi; less than ten movements with one pause means all Five Zang lack Qi. Prognosis depends on the beginning and end. Fifty movements without pause is the norm, indicating the lifespan of the Five Zang. Prognosis of short life is indicated by irregular rhythm.
Zhang Jingyue stated: The "Nan Jing" asks: If the pulse stops after fewer than fifty movements, indicating one Zang lacks Qi, which Zang is it? The answer is: Inhalation follows Yin inward, exhalation follows Yang outward. If inhalation cannot reach the Kidney but returns at the Liver, it indicates that the Kidney Qi is exhausted first. Thus, harmonious Five Zang yield long Qi/pulse; diseased Five Zang yield short Qi/pulse. Observing this, if one Zang lacks Qi, it must involve the Kidney first. For two, three, four, or five Zang lacking Qi, the progression should be from distal to proximal, becoming progressively shorter: Kidney to Liver, Liver to Spleen, Spleen to Heart, Heart to Lung. Therefore, in critical illness, rapid breathing resembling asthma, confined to a few inches in the chest, indicates True Yin exhaustion below and Floating Lone Yang above—the extreme of short Qi. At this stage, any attempt to balance the condition will inevitably lead to death. Life and death depend on Qi; Qi aggregation and dispersion depend on Yin; survival relies on a thread of unextinguished Qi. Thus, Zang Qi must be carefully examined.
He further stated: The meaning of Dai Mai (Intermittent Pulse) since Zhang Zhongjing and Wang Shuhe has been described as a pulse that stops during movement, cannot return spontaneously, resumes, stops again, and after searching for a long time, rises weakly. Thus, later generations grouped Jie (Knotted), Cu (Rapid-intermittent), and Dai together as "stopping pulses," but this does not exhaust their meanings. Slow pulse with one stop is Jie; rapid pulse with one stop is Cu. The stops may vary (every 3rd, 5th, 7th, or 8th beat). These have clear rhythms and forceful starts/stops. Causes include Qi rebellion and phlegm obstruction, Qi and Blood collapse leading to discontinuity, or innate sluggishness of the pulse channel. These define Jie and Cu.
However, Dai Mai is different. "Xuan Ming Wu Qi Lun" states the Spleen pulse is Dai; "Zang Fu Bing Xing Pian" states yellow complexion corresponds to Dai pulse. Both refer to the normal fluctuation of Zang Qi, not necessarily a stop. "Ping Ren Qi Xiang Lun" states "Only Dai without Stomach Qi indicates death," referring to the loss of Stomach Qi and appearance of True Zang Qi, not merely a stop. Thus, Dai has multiple meanings. Fifty movements without a pause refers to the numerical regularity mentioned in the text. If the pulse is normally even but suddenly varies in strength, it is a morphological Dai, as described in "Ping Ren Qi Xiang Lun." If the Spleen governs the four seasons and changes accordingly, it is a climatic Dai, as in "Xuan Ming Wu Qi Pian." Any pulse without a fixed pattern that changes frequently is called Dai, but one must observe the variation to understand the condition. The original text only mentions movement and stopping to diagnose Zang Qi deficiency, without explicitly stating a death date. However, Wang Bing's commentary suggests that a slow pulse with one stop (one Zang lacking Qi) leads to death four years later when spring grass grows. This seems unlikely, as living four years with one Zang lacking Qi, or three years with two, defies logic. Practitioners should discern this carefully.