伏脉大旨，《简摩补义》言之悉矣。陶节庵谓伤寒两手脉乍伏者，此将欲得汗也，邪汗
发之
，正汗勿发之。其所以乍伏之故，尚未指出。夫欲汗而脉反乍伏者，皆因邪气滞入血脉，正
气欲伸而血阻之不能骤伸，以致折其方伸之锐气，而相格如此也；或伤寒日久，阴盛阳虚，
血脉凝泣，得温补之剂，阳气乍充，鼓入血脉，寒邪不得骤开，故相搏而气机乍窒也；或温
病大热，津灼血燥，得养阴之剂，津液初回，正气鼓之，以入血脉，血燥不能骤濡，气机不
能骤利，故相迫而致闭也；亦有内伤生冷，外伤风寒，胸口结痛，呼吸喘促，得温化之剂，
脾阳乍动，冷食初化，而表邪未开，以致格拒，而气乍窒者；亦有燥屎内结，表邪尚在，得
润降之剂燥屎将下，正气运于内，不及捍于表，表邪乘机内移，正气又旋外复，以致相激，
而气乍窒者。此皆气急欲通，而未得遽通所致。若本有汗，及下利不止，而忽然无脉者，真
气散、气脱也；又有伤风日久，或先经误汗，阴虚戴阳，津空气结，气搏于表，其脉浮薄，
止 于皮毛之间，稍按即散，得生津之剂，阳气乍交于阴，其脉内敛。何者?凡气必先一
吸而后能一嘘也。此证若不先用生津，以辛温强汗之，脉气不得先伏，而即出汗，即刻气喘
而脱矣。前伏为邪正之相搏，此伏为阴阳之相交。其得汗，皆所谓战汗之类。邪正相搏者，
其躁扰往往甚厉，吴又可谓之狂汗。阴阳相交者，正虚邪微，但略见口噤、肢厥而已。陶节
庵有正汗、邪汗之辨。邪汗即邪正相搏者也，故曰发之，谓助其正气也。
伏脉的总体要旨，《简摩补义》一书中已经阐述得非常详尽了。陶节庵认为，伤寒病患者两手脉搏突然隐伏，这是即将出汗的征兆，这种因邪气引发的汗需要发散治疗，而正常的汗则不需要发散。但他尚未指出脉搏突然隐伏的根本原因。
凡是想要出汗但脉搏反而突然隐伏的情况，都是因为邪气阻滞进入血脉，正气想要伸展却被血液阻滞而不能骤然伸展，从而挫伤了正气刚刚萌发的锐气，导致正气与邪气相互格拒，出现这种情况；或者是因为伤寒日久，阴寒盛而阳气虚，血脉凝滞涩滞，服用温补药剂后，阳气突然充盈，鼓动进入血脉，但寒邪不能骤然消散，所以相互搏结导致气机突然窒塞；或者是温病高热，津液被灼烧导致血液干燥，服用养阴药剂后，津液刚开始恢复，正气鼓动津液进入血脉，但血液干燥不能骤然濡润，气机不能骤然通畅，所以相互逼迫导致闭阻；也有因为内伤生冷食物，外感风寒，胸口结聚疼痛，呼吸急促，服用温化药剂后，脾阳突然发动，冷食刚开始消化，但表邪未散，导致格拒，气机突然窒塞的情况；还有因为燥屎在体内结聚，表邪尚在，服用润降药剂后燥屎将要下行，正气运行于体内，来不及护卫体表，表邪趁机内移，正气又随即向外回复，导致相互激荡，气机突然窒塞的情况。这些都是气急欲通，却未能立刻通畅所致。如果原本就有汗出，以及腹泻不止，却忽然无脉，那是真气涣散、气脱的表现；又有伤风日久，或者先前经过误用发汗法，导致阴虚戴阳（虚阳上浮），津液枯竭气机郁结，气搏结于体表，其脉象浮而薄弱，仅停留在皮毛之间，稍微按压就散失，服用生津药剂后，阳气突然与阴相交，其脉象内敛。为什么呢？凡气必须先吸入后才能呼出。此证如果不先用生津药，而用辛温药强行发汗，脉气不得先隐伏，而是立即出汗，即刻就会气喘并导致气脱。前面的伏脉是邪气与正气的相互搏结，这里的伏脉是阴阳的相互交合。这两种情况得到的汗，都属于所谓的“战汗”之类。邪正相搏的情况，患者往往躁扰非常厉害，吴又可称之为“狂汗”。阴阳相交的情况，正气虚弱邪气微弱，只是略微见到牙关紧闭、四肢厥冷而已。陶节庵有对正汗和邪汗的辨别。邪汗就是邪正相搏的结果，所以说要发散它，意思是助长正气。
The general principles of the Hidden Pulse (Fu Mai, 伏脉) have been exhaustively discussed in *Jianmo Buyi* (Supplementary Commentary on Jianmo). Tao Jie'an stated that when the pulses in both hands suddenly become hidden in patients with Cold Damage (Shanghan, 伤寒), this indicates that sweating is imminent. The sweat induced by pathogenic factors requires dispersing treatment, whereas normal physiological sweating does not. However, he did not point out the underlying reason for this sudden hiding of the pulse.
In cases where sweating is desired but the pulse suddenly becomes hidden, it is generally because pathogenic factors have stagnated and entered the blood vessels. The healthy Qi attempts to extend but is obstructed by the blood, preventing it from extending abruptly. This frustrates the initial sharp momentum of the healthy Qi, leading to mutual obstruction between the healthy Qi and the pathogen. Alternatively, in prolonged Cold Damage, Yin excess and Yang deficiency cause the blood vessels to congeal and flow sluggishly. Upon administering warming and tonifying formulas, Yang Qi suddenly fills and surges into the blood vessels. Since the cold pathogen cannot dissipate abruptly, the two contend, causing a sudden obstruction of Qi mechanism. In severe Warm Diseases (Wenbing, 温病) with high fever, fluids are scorched and blood becomes dry. After administering fluid-nourishing formulas, as fluids begin to return and healthy Qi drives them into the blood vessels, the dry blood cannot be moistened abruptly, and the Qi mechanism cannot flow smoothly immediately. This mutual pressure leads to closure. There are also cases of internal injury from raw/cold foods and external contraction of wind-cold, presenting with chest constriction and pain, and rapid breathing. After administering warming and resolving formulas, Spleen Yang suddenly activates, and cold food begins to digest. However, since exterior pathogens remain unresolved, mutual rejection occurs, causing sudden Qi obstruction. Furthermore, in cases of internal accumulation of dry stool with lingering exterior pathogens, after administering moistening and purging formulas, as dry stool prepares to descend, healthy Qi moves inward and fails to defend the exterior. Seizing the opportunity, exterior pathogens shift inward, while healthy Qi rotates back outward. This mutual agitation causes sudden Qi obstruction. All these scenarios result from Qi urgently seeking unobstruction but failing to achieve it abruptly.
If a patient who already has sweating or persistent diarrhea suddenly presents with no pulse, this indicates the dispersion of True Qi and Qi collapse. Another scenario involves prolonged Wind Injury or prior misapplication of diaphoresis, leading to Yin deficiency with floating Yang (Daiyang, 戴阳), depleted fluids, and knotted Qi. When Qi contends at the exterior, the pulse may appear floating and thin, confined to the skin and hair level, scattering upon slight pressure. After administering fluid-generating formulas, Yang Qi suddenly interacts with Yin, and the pulse becomes contained internally. Why? Because Qi must first inhale before it can exhale. If this condition is treated with pungent-warm herbs to force sweating without first generating fluids, the pulse Qi will not hide beforehand; instead, immediate sweating will occur, leading instantly to panting and Qi collapse. The former type of Hidden Pulse represents the contention between pathogenic and healthy Qi, while the latter represents the interaction between Yin and Yang. The sweating obtained in both cases belongs to what is termed "Zhanhan" (Battle Sweat, 战汗). In cases of pathogenic-healthy Qi contention, restlessness is often severe, which Wu Youke described as "Kuanghan" (Mad Sweat, 狂汗). In cases of Yin-Yang interaction, healthy Qi is weak and pathogens are mild, manifesting only slightly as clenched jaws and cold extremities. Tao Jie'an distinguished between Zhenghan (Normal Sweat, 正汗) and Xiehan (Pathogenic Sweat, 邪汗). Pathogenic sweat results from the contention of pathogenic and healthy Qi; hence, it is said to require dispersing, meaning to assist the healthy Qi.