六代者。阴也。指下寻之。动而复起。再再不能自还。曰代。主形容羸瘦。口不
能言。
六代者。阴也。中土之象也。代而谓有中土之象者。何也。谓其动而中止
也。然促结之脉。亦动而中止。不谓之土也。以促结虽动而中止。无有常
数。代则不然。动而中止有常数也。何谓止有常数。假令五动一止。仍是
五动也。七动一止仍是七动也。代有常数。而谓之土者何也。以土主信。
不失其期也。凡病之不失其期者。皆土之为病也。动而中止。不失其期。
而谓之代者何也。谓一脏无气。而以他脏代之也。平人之脉。一动肺。二
动心。三动脾。四动肺。五动肾。周而复始。至五十动不止。以成大衍之数。
故曰平人。假令七动一止。谓心脏无气。再而后起。不能自还。是心脏无
气而脾脏代之也。故所主之病。形容羸瘦。形已脱矣。口不能言。气已脱
矣。形气俱脱。不死何为。
按脉经云。代脉来数中止。不能自还。因而复动。脉结者生。代者死。又刘
守真曰。代脉者主缓弱而无力。不能动。因而复动。病必危而死。
代脉时时动若浮。再而复起似还无。三元正气随风去。魂魄冥冥何所拘。
代脉时时。其状若浮。但浮脉按之有神无间断。代脉按之无根。而有间
断。虽有时再起。而止有常数。是一脏气绝。而以他脏代之也。夫神所以
御气气所以御精。三者互摄。则魂魄自相拘守。今脉而见代。则三元之
精气。神已散而魂魄亦相离而失守。不死何为。此节正与肺藏歌内魂
将魄共连之句。互相遥映。
按脉经云。代散则死。
代脉有六次跳动后出现一次间歇，属于阴脉。在指下寻按脉搏时，脉搏跳动后再次兴起，但反复出现且不能自行恢复连续节奏，称为“代”脉。此脉主要主病表现为形体消瘦、口不能言。
代脉有六次跳动后出现一次间歇，属于阴脉，也是中土（脾）的征象。为什么说代脉具有中土的征象呢？是因为它的脉搏跳动中途停止。然而，促脉和结脉也是脉搏跳动中途停止，却不被称为属土。这是因为促脉和结脉虽然也有跳动中途停止的现象，但没有固定的规律；而代脉则不同，它的跳动中途停止是有固定规律的。什么叫停止有固定规律？例如，假设脉搏跳动五次后停止一次，那么它仍然是以五次为一个周期继续跳动；跳动七次后停止一次，也是以七次为一个周期。代脉之所以被称为属土，是因为土的特性是守信，不违背其期限。凡是疾病的发展不违背其期限的，都是土（脾）受邪所致。脉搏跳动中途停止且不违背其期限，为什么称之为“代”呢？这是因为某一脏的气已绝，由其他脏来代为搏动。正常人的脉搏，第一次跳动对应肺，第二次对应心，第三次对应脾，第四次对应肺，第五次对应肾，循环往复，直到五十次跳动不停止，符合大衍之数的规律，所以称为平人（健康人）。假如脉搏跳动七次后停止一次，说明心脏无气，停顿后再起搏，但不能自行恢复常态，这是心脏无气而由脾脏代为搏动。因此，它所主的病症是形体极度消瘦，说明形气已脱；口不能言语，说明真气已脱。形与气都衰竭了，如果不死，还能怎样呢？
根据《脉经》记载：代脉来势较快，中途停止，不能自行恢复，因而再次搏动。脉象呈结脉者尚可生，呈代脉者则主死。另外，刘守真说：代脉主要表现为缓弱无力，脉搏难以搏动，因而再次搏动，病情必定危重致死。
代脉时时搏动，形态若浮脉，再次兴起似乎要恢复却终究没有恢复。三元正气随风消散，魂魄冥冥之中无所拘束。代脉时时搏动，其状似浮脉，但浮脉重按时有神气且无间断；代脉重按则无根，且有间断。虽然有时再次搏起，但停止的次数有固定规律，这是一脏之气已绝，由他脏代为搏动。神用来驾驭气，气用来驾驭精，三者互相摄持，则魂魄自然相互约束守护。如今脉象出现代脉，则元精、元气、元神（三元）的精气，神已散失，魂魄也分离而失守。如果不死，还能怎样呢？这一节的内容正与《肺藏歌》中“魂将魄共连”的句子，互相遥相呼应。
根据《脉经》记载：代脉若兼见散脉特征，则主死。
The Dai pulse (Intermittent Pulse) with six beats before an interruption is Yin. When palpating with the fingers, the pulse beats and then rises again, repeatedly failing to resume its rhythm spontaneously; this is called "Dai" (Intermittent). It primarily indicates conditions characterized by emaciation and inability to speak.
The Dai pulse with six beats before an interruption is Yin, representing the image of the Central Earth (Spleen). Why is it said that the Dai pulse possesses the image of Central Earth? Because its movement halts midway. However, the Cu (Surging) and Jie (Knotted) pulses also halt midway in their movement, yet they are not attributed to Earth. This is because although the Cu and Jie pulses halt midway, they lack a constant number or regularity. The Dai pulse is different; its halting has a constant number. What does it mean that the halting has a constant number? For example, if there is one stop after five beats, it continues as five beats per cycle; if there is one stop after seven beats, it continues as seven beats per cycle. Why is the Dai pulse attributed to Earth? Because Earth governs trustworthiness and does not miss its appointed time. Any disease that proceeds according to a fixed schedule is caused by the pathology of Earth. Why is the halting of movement without missing its schedule called "Dai"? It means that when one Zang organ lacks Qi, another Zang organ takes over to beat. In a healthy person's pulse, the first beat corresponds to the Lung, the second to the Heart, the third to the Spleen, the fourth to the Lung, and the fifth to the Kidney, cycling continuously. If it reaches fifty beats without stopping, fulfilling the number of Great Expansion (Da Yan), it is considered a healthy person. Suppose the pulse stops once after seven beats; this indicates the Heart lacks Qi. After pausing, it resumes but cannot recover spontaneously; this means the Heart lacks Qi and the Spleen takes over. Therefore, the diseases indicated include extreme emaciation, showing that the Form has collapsed, and inability to speak, showing that the Qi has collapsed. With both Form and Qi exhausted, how could death not occur?
According to the *Mai Jing* (Pulse Classic): The Dai pulse comes rapidly, halts midway, cannot return spontaneously, and thus moves again. A Jie (Knotted) pulse indicates survival, whereas a Dai pulse indicates death. Furthermore, Liu Shouzhen stated: The Dai pulse is primarily slow, weak, and powerless, difficult to move, and thus moves again; the illness must be critical and fatal.
The Dai pulse beats intermittently, resembling a Fu (Floating) pulse; it rises again seemingly returning but ultimately does not. The Three Primes' (Yuan Jing, Yuan Qi, Shen) righteous energy dissipates with the wind; the Hun and Po souls wander dimly, bound by nothing. The Dai pulse beats intermittently, its appearance resembling the Floating pulse. However, while the Floating pulse feels spirited and uninterrupted upon deep pressure, the Dai pulse feels rootless and interrupted upon deep pressure. Although it sometimes rises again, the intervals have a constant number, indicating that the Qi of one Zang organ has ceased, and another Zang organ takes over. Spirit (Shen) commands Qi, and Qi commands Essence (Jing); these three mutually sustain each other, so the Hun and Po naturally guard each other. Now, seeing the Dai pulse, the essence of the Three Primes is scattered; the Shen has dispersed, and the Hun and Po have separated and lost their guardianship. How could death not occur? This section echoes the line "Hun and Po connect together" in the Song of the Lung Organ.
According to the *Mai Jing*: If the Dai pulse combines with the San (Scattered) pulse characteristics, it indicates death.