次则中焦饮遏。次则水气外溢。于是水饮之情状。纤悉无遗。而加以兼虚挟热。
可谓密矣。
先渴后呕。为水停心下。
〔徐〕饮有久暂不同。此云先渴后呕。渴必多饮。从无呕证。而忽于渴后见之。其为水饮无疑矣。故曰。此属饮家。
临时伤饮也。〔鉴〕水停心下。中焦部也。中焦属胃。故不止病悸短气。而亦病呕也。病悸短气者。是水停胃外。
从膈下而上干于胸也。病呕者。是水停胃内。从胃中而上越于口也。
〔余述〕许学士称。平生病膈中停饮。觉酒止从左边下。漉漉有声。胁痛。饮食殊减。十数日必呕数升酸苦水。后
揣度之。已成癖囊。如潦水之有科曰。不盈科不行。水盈科而行也。清者可行。浊者依然 。盖下无路以决之也。是
以积之五六日。必呕而去。稍宽数日复作。脾。土也。恶湿。而水则流湿。莫若燥脾以胜湿。崇土以填科曰。则病当去
矣。于是悉屏诸药。一味服苍术。三月而疾除。云云。愚以为许氏所患。即支饮中一证。其所辨说。殊为精核。盖如苓
桂术甘汤。泽泻汤。小半夏。及加茯苓汤。茯苓饮等证。皆是支饮之自脾土失权而致者。
即所谓癖囊也。癖囊之名。今世多唱之者。而少知其实为支饮者。又莫识支饮之证。得许氏之言。而其理更明者。
故愚今表而论之。（癖囊。本作 囊。出千金痰饮中。）
Subsequently, the middle jiao is obstructed by fluid retention. Then, water qi overflows outward. Thus, the characteristics and manifestations of fluid retention are depicted in meticulous detail, further complicated by concurrent deficiency and heat conditions. The analysis can be considered rigorous.
Thirst preceding vomiting indicates fluid stagnation in the epigastrium (heart below).
[Commentary by Xu Lingtai]: Fluid retention varies in duration. The text states "thirst precedes vomiting"; thirst inevitably leads to increased drinking. Normally, there is no vomiting symptom, yet it suddenly appears after thirst. This is undoubtedly caused by fluid retention. Hence it is said that this belongs to individuals with pre-existing fluid pathology.
This is acute injury due to fluid retention. [Commentary by You Zaijing]: Fluid stagnation in the epigastrium belongs to the middle jiao region. The middle jiao is associated with the Stomach; therefore, besides palpitations and shortness of breath, vomiting also occurs. Palpitations and shortness of breath arise because fluid stagnates outside the stomach, rising from below the diaphragm to harass the chest. Vomiting occurs because fluid stagnates inside the stomach, surging upward from the stomach cavity to the mouth.
[Additional Commentary]: Scholar Xu stated that he suffered from chronic fluid retention in the diaphragm area throughout his life. He felt that wine only flowed downward on the left side, producing a gurgling sound, accompanied by hypochondriac pain and significantly reduced food intake. Every ten or so days, he would vomit several sheng of sour and bitter fluid. Later, upon analyzing the condition, he deduced that a "Pi Nang" (a type of accumulation mass) had formed. This is akin to the saying in *Mencius*: "Water does not flow until the hollows are filled." Water flows only when the hollows are full. Clear fluids can flow, while turbid fluids remain stagnant because there is no outlet for drainage. Consequently, after accumulating for five to six days, it must be expelled through vomiting. It subsides slightly for a few days before recurring. The Spleen belongs to Earth and dislikes dampness, whereas water tends to flow toward damp areas. Therefore, it is best to dry dampness and strengthen the Spleen to overcome dampness, and fortify Earth to fill the hollows. In doing so, the disease should resolve. Thus, he discontinued all other medications and took only *Cangzhu* (Rhizoma Atractylodis Macrocephalae) alone. After three months, the illness was cured. Etc. I believe that what Scholar Xu suffered from was a specific manifestation of Branch Fluid Retention (Zhi Yin). His differentiation and explanation were particularly precise. Formulas such as Linggui Zhugan Tang (Poria, Cinnamon Twig, Atractylodes Macrocephala, and Licorice Decoction), Zexie Tang (Alisma Decoction), Xiao Banxia Tang (Minor Pinellia Decoction), Xia Banxia Jia Fuling Tang (Minor Pinellia Decoction plus Poria), and Fuling Yin (Poria Drink) are all conditions where Branch Fluid Retention results from the loss of regulatory function of the Spleen Earth. These correspond to what is called "Pi Nang". Although the term "Pi Nang" is widely used today, few know its true nature as Branch Fluid Retention. Moreover, few can identify the symptoms of Branch Fluid Retention. With Scholar Xu's insights, the principles become even clearer. Therefore, I hereby elaborate on this topic. ("Pi Nang", originally written as "Pi Nang", appears in the Chapter on Fluid Retention in *Qianjin Fang*).