肺萎，肺之大叶不举也。其外症以咳而唾白沫者为真。《病源》或兼欲咳不能咳及呕逆
、小
便言之，成无己注《伤寒论》，则以咽喉不利、唾脓血为肺萎，皆非的候。惟《外台》引许
仁则云肺萎之状，“唾白如雪，细沫稠粘。”此八字深得仲景言外之意，最为的当。若巢、
成所说，乃其兼症，或有或无，未可必也。肺萎病当属六极，气极之一也，多在久嗽之后，
骨蒸之余，其甚者白沫中带血，且或带脓焉。故《金匮》云咳唾脓血，脉数虚者为肺萎，数
实
者为肺痈。仲景以脉之异，辨其症之同，亦可知脓血不独肺痈有之。详余所撰《证原》中。
目裹肿、颈脉动、时咳诸症，正水与风水同。但有此诸症，而按其肿上随手起者正水，
不起
者风水，以此为别。且必股冷腹大，乃为正水已成，则正水重于风水也。《灵·水胀》水始
起
也，目裹上微肿，如新卧起之状，其颈脉动，时咳，阴股间寒，足胫肿，腹乃大，其水已成
矣。以手按其肿（俗本“肿”作“腹”，今从《病源》引）随手而起，如裹水之状。《金匮·
水气》视人之目裹上微肿，如新卧起状，其颈脉动，时咳，按其手足上陷而不起者风水。文
义甚明。《病源》于水肿，全据《灵枢》，于风水，全据《金匮》，分别当已。惟风水久久
变成水病，则亦按之随起，
故《肘后方》曰∶水病之初，先两目上肿起，
如老蚕色，侠颈脉动，股里冷，胫中满，按之没指，腹内转侧有
声，此其候也；不即疗，须臾身体稍肿，腹尽胀，按之随手起，则病已成。非与经违也。葛
意以风水为正水之初起，而浑言之曰水者，亦以有股里冷一症耳！实与诸经相成也。
肺萎，是指肺部的大叶不能正常舒展。其典型的外在症状是咳嗽并吐出白色泡沫。《诸病源候论》中有时还提到想咳却咳不出来以及呕吐逆气、小便异常等情况；成无己在注释《伤寒论》时，则将咽喉不利、吐脓血作为肺萎的症状，这些都不是确切的指征。只有《外台秘要》引用许仁则的说法：“吐出白色泡沫像雪一样，细沫稠密粘稠。”这八个字深得张仲景言外之意，最为恰当。至于巢元方、成无己所说的，属于伴随症状，有或没有，不一定具备。肺萎病应当归属于“六极”之中，是“气极”的一种，多发生在长期咳嗽之后，或者骨蒸劳热之余。病情严重的，白沫中带有血液，甚至可能带有脓液。所以《金匮要略》说：咳嗽吐脓血，脉象数而虚的是肺萎；脉象数而实的是肺痈。张仲景通过脉象的不同来辨别症状相同（都有脓血）的疾病，也可以知道脓血并不只是肺痈才有。详细情况见我撰写的《证原》一书中。
眼睑浮肿、颈部动脉搏动明显、时常咳嗽等症状，正水与风水是相同的。但是有了这些症状后，如果按压肿胀部位，手松开后凹陷立即恢复的是正水；凹陷不立即恢复的是风水，以此作为区别。而且必须伴有小腿发冷、腹部胀大，才是正水已经形成，那么正水的病情比风水重。《灵枢·水胀篇》记载：水病刚开始时，眼睑上方微微肿胀，像刚睡醒的样子，颈部脉搏跳动，时常咳嗽，大腿内侧发冷，小腿肿胀，腹部才变大，这时水邪已经形成了。用手按压肿胀处，手松开后凹陷立即弹起，像包裹着水一样的状态。《金匮要略·水气病脉证并治》中说：看人的眼睑上方微微肿胀，像刚睡醒的样子，颈部脉搏跳动，时常咳嗽，按压手足部，凹陷不起的是风水。文义非常明确。《诸病源候论》关于水肿，完全依据《灵枢》，关于风水，完全依据《金匮要略》，区分得当。只是风水久了会变成水病，那时按压也会随按随起，所以《肘后备急方》说：水病初期，先两眼上肿起，颜色像老蚕色，夹着颈部脉搏跳动，大腿里发冷，小腿胀满，按压凹陷至指痕，腹内转动时有声音，这是它的征兆；如果不立即治疗，一会儿身体稍微肿胀，腹部全部胀满，按压后随手而起，则是病已成形。这并不违背经典经文。葛意认为风水是正水的初起阶段，笼统地称之为水病，也是因为有“大腿里发冷”这一症状的缘故！实际上这与各经文的论述是相辅相成的。
Fei Wei (Lung Atrophy), refers to the condition where the large lobes of the lung fail to expand normally. Its characteristic external symptom is coughing and spitting out white foam. *Zhubing Yuanhou Lun* (Treatise on the Pathogenesis and Manifestations of All Diseases) sometimes also mentions symptoms such as the desire to cough but inability to do so, vomiting with regurgitation, and urinary abnormalities; Cheng Wuji, in his commentary on *Shanghan Lun* (Treatise on Cold Damage), took throat discomfort and spitting of pus and blood as symptoms of Fei Wei, which are not accurate indicators. Only the quote from Xu Renze cited in *Waitai Miyao* (Essential Prescriptions Worth a Thousand Gold for Emergencies): "Spitting white foam like snow, fine bubbles thick and sticky." These eight characters deeply capture the implicit meaning of Zhang Zhongjing's words and are the most appropriate. What Niao Yuanfang and Cheng Wuji described belong to accompanying symptoms, which may or may not be present, and cannot be assumed to always exist. Fei Wei disease should be classified under the "Six Extremities" (Li Ji), specifically as one type of Qi Extreme (Qi Ji). It mostly occurs after prolonged coughing or following bone-steaming consumption (Gu Zheng). In severe cases, the white foam contains blood, and sometimes even pus. Therefore, *Jin Gui Yao Lue* (Essential Prescriptions of the Golden Cabinet) states: Coughing and spitting pus and blood, with a rapid and deficient pulse indicates Fei Wei; a rapid and excess pulse indicates Fei Yong (Lung Abscess). Zhang Zhongjing distinguished diseases with similar symptoms (both having pus and blood) by differentiating their pulses, showing that pus and blood are not exclusive to Fei Yong. For details, see my work *Zheng Yuan*.
Periorbital edema, pulsation of the neck vessels, and occasional cough are common to both Zheng Shui (True Water Retention) and Feng Shui (Wind Water). However, when these symptoms are present, pressing the swollen area results in immediate rebound if it is Zheng Shui, whereas it does not rebound immediately if it is Feng Shui; this serves as the distinction. Furthermore, only when accompanied by coldness in the thighs and abdominal distension can it be confirmed as established Zheng Shui, indicating that Zheng Shui is more severe than Feng Shui. *Ling Shu: Shui Zhang* (Spiritual Pivot: Water Swelling) records: When water disease begins, there is slight swelling above the eyelids, resembling the appearance after just waking up; the neck vessels pulse, there is occasional coughing, coldness between the inner thighs, swelling of the calves, and then the abdomen becomes enlarged, indicating that the water pathogen has formed. Pressing the swelling causes the indentation to rebound immediately upon releasing the hand, resembling a state of being wrapped in water. *Jin Gui Yao Lue: Shui Qi* (Water Qi) states: Observing slight swelling above the eyelids, resembling the appearance after just waking up, pulsation of the neck vessels, occasional coughing, and depression upon pressing the hands and feet that does not recover immediately indicates Feng Shui. The textual meaning is very clear. *Zhubing Yuanhou Lun*, regarding edema, relies entirely on *Ling Shu*; regarding Feng Shui, it relies entirely on *Jin Gui Yao Lue*, making appropriate distinctions. However, since Feng Shui can transform into general water disease over time, at which point pressing will also show immediate rebound, *Zhou Hou Bei Fang Ji Fang* (Handbook of Prescriptions for Emergencies) states: In the early stage of water disease, the eyes first swell upwards, with a color resembling an old silkworm, along with pulsation of the neck vessels, coldness in the thighs, fullness in the shins, depression upon pressing that leaves an imprint, and sounds within the abdomen when turning; this is its sign. If not treated immediately, soon the body swells slightly, the entire abdomen becomes distended, and pressing results in immediate rebound, indicating the disease has taken form. This does not contradict the classics. Ge Yi considered Feng Shui as the initial stage of Zheng Shui and generally referred to it as water disease, primarily due to the symptom of coldness in the thighs! In reality, this complements the descriptions in various classic texts.