外感者，先太阳，次阳明，次少阳，次太阴，次少阴，次厥阴；内感者，先三阴而无定
，次少阳，次阳明，次太阳，为极高之分。
阳从内消，从右手脉先陷，左手浮，右手沉。
阳从外走，从左手脉先陷，右手浮，左手沉。
其脉或有不然者，阴阳之变易无定也。许学士云∶阴阳交互最明，正坐此耳！
阳脉沉而滑，若浮者，欲升而汗也。
阴脉沉而细，本体也。
若浮而有力者，阳气生也。
若浮而无力者，阳气走也。
若浮若沉，或有力，或无力，阴阳交争而未定也，惟外热内寒者，多有此脉。
古人用附子，不得已也，皆为身凉脉沉细而用之。若里寒身表大热者不宜用，以其附子
味辛
身热消而变凉，内外俱寒，姜附合而并进，温中行经，阳气俱生，内外而得可保康宁，此
之谓也。若身热便用附子，切恐转生他证，昏冒不止。可慎！可慎！
阴阳各相易证，仲景止用烧 散，言至简而意至有余也。故朱奉议立阴阳易证为二条，
后人始知有寒热之别也。故热者有上烧 散，而又有竹皮茹汤，寒者有 鼠粪汤，而又
有当归白术汤。至于枝正方妙香丸条下，治杂病阴阳易，药中有牛黄、脑、麝之类，是知治
热证也，岂可一涂而取哉？学人详之。
圣人立阴阳易条，虽不尽言，特举其宏纲而已，是以后之述者，尽心焉尔矣可也。
海藏云∶若阴阳易证，果得阴脉，当随证用之。
若脉在厥阴，当归四逆汤送下烧 散。
若脉在少阴，通脉四逆汤送下烧 散。
若脉在太阴，四顺理中汤送下烧 散。
所用之药，各随其经而效为之速也，宜矣！
上此一条，随经药下烧 散，所以补古人所不完处。
扁鹊云∶治阴阳易伤寒，烧妇人月经衣，热水服方寸匕。仲景云∶伤寒阴阳之为弱，其
人身体重，少气，少腹里急，或引阴中拘挛，热上冲胸、头重不欲举，眼中生花，膝胫拘急者，
烧散主之。
Exogenous diseases first affect the Taiyang (Greater Yang) channel, followed by the Yangming (Yang Brightness) channel, then the Shaoyang (Lesser Yang) channel, subsequently the Taiyin (Greater Yin) channel, then the Shaoyin (Lesser Yin) channel, and finally the Jueyin (Terminal Yin) channel; endogenous diseases first affect the Three Yin channels without a fixed order, followed by the Shaoyang channel, then the Yangming channel, and lastly the Taiyang channel, representing the stage of extreme depth.
When Yang qi dissipates from within, the pulse at the right wrist sinks first, while the left is floating and the right is sunken.
When Yang qi escapes from the exterior, the pulse at the left wrist sinks first, while the right is floating and the left is sunken.
The pulse may sometimes not follow this pattern, as the transformation and alternation of Yin and Yang have no fixed rule. Scholar Xu stated: The interaction of Yin and Yang is most evident, precisely based on this principle!
A Yang pulse that is deep and slippery, if it becomes floating, indicates that Yang Qi is attempting to ascend and sweat will occur.
A Yin pulse that is deep and fine is its original state.
If it is floating and forceful, it indicates that Yang Qi is generating.
If it is floating and weak, it indicates that Yang Qi is dissipating.
If the pulse is either floating or sunken, either forceful or weak, it signifies that Yin and Yang are contending without stability; such pulses are mostly seen in conditions with external heat and internal cold.
Ancients used Fuzi (Prepared Aconite Root, *Aconiti Lateralis Radix Praeparata*) only out of necessity, specifically when the body was cold and the pulse was deep and fine. If there is internal cold but significant external heat, it should not be used, because Fuzi is acrid in flavor; using it would cause body heat to dissipate and turn cold, resulting in both interior and exterior cold. When Shengjiang (Prepared Ginger Rhizome, *Zingiberis Rhizoma Praeparatum*) and Fuzi are combined and administered together, they warm the middle jiao and meridians, allowing Yang Qi to generate jointly, thereby ensuring health and peace inside and outside; this is the rationale. If one uses Fuzu immediately upon the presence of body heat, there is great fear of inducing other syndromes and continuous mental confusion. One must be cautious! Must be cautious!
Regarding the various syndromes of Yin-Yang Exchange (a condition occurring after recovery from severe disease due to sexual activity), Zhang Zhongjing only utilized Shao Kun San (Burning Underwear Powder). His words were extremely concise yet profoundly rich. Therefore, Zhu Fengyi divided Yin-Yang Exchange syndromes into two categories, after which later scholars realized the distinction between cold and heat syndromes. Thus, for heat syndromes, there is Shao Kun San and also Zhupi Ru Tang (Bamboo Flake and Rhusia Decoction); for cold syndromes, there is Shu Fen Tang (Mouse Dropping Decoction) and also Danggui Baizhu Tang (Angelica and Atractylodes Macrocephala Decoction). In the entry for Zhifang Zheng's Miaoxiang Wan (Wonderful Fragrance Pill), which treats miscellaneous diseases involving Yin-Yang Exchange, the formula contains substances like Niuhuang (Calculus Bovis, *Bovis Calculus*) and Nao, She (Camphor and Musk), indicating it treats heat syndromes. How can one adopt a single uniform method? Scholars should study this carefully.
The Sages established the articles on Yin-Yang Exchange, though not detailing everything, merely listing the general outline; thus, it is appropriate for later commentators to devote their utmost effort to elaboration.
Haizang (Wang Haogu) said: If a Yin-Yang Exchange syndrome indeed presents with a Yin pulse, one should treat according to the specific manifestations.
If the pulse relates to the Jueyin channel, administer Shao Kun San with Danggui Sini Tang (Angelica Cinnamon Twig Decoction).
If the pulse relates to the Shaoyin channel, administer Shao Kun San with Tongmai Sini Tang (Pulse-Returning Decoction).
If the pulse relates to the Taiyin channel, administer Shao Kun San with Sishun Lizhong Tang (Four-Gentle Warm Middle Decoction).
The medications used, each tailored to the affected channel, yield rapid efficacy, which is fitting!
The aforementioned section, prescribing channel-specific medicines alongside Shao Kun San, serves to supplement the incompleteness of ancient texts.
Bian Que stated: To treat Yin-Yang Exchange Shanghan, burn a woman's menstrual undergarment and take one cun-bi (a measure equivalent to a spoonful) with hot water. Zhang Zhongjing stated: In Shanghan Yin-Yang Exchange leading to weakness, where the patient has heavy limbs, shortness of breath, urgency and pain in the lower abdomen, possibly drawing into spasms in the genital area, heat rushing up to the chest, heaviness in the head making lifting difficult, blurred vision ("seeing flowers"), and stiffness/spasms in the knees and shins, Shao Kun San is the primary treatment.