内经云。太阳之胜。火气内郁。流散于外。足 肿。饮发于中。 肿于上。又云。脾脉搏坚
而长。其色黄。当病少气。其 而散色不泽者。当病足 肿。若水状也。脾病者、身重肉痿。足不
能行。善 。脚下痛。此谷入多而气少。湿居下也。故湿从下受之。如上所说。皆谓脾胃湿气下流
。乘其肝肾之位。由是足胫疼痛而 肿也。夫五谷入胃。糟粕、津液、宗气。分为三隧。故宗气积
于胸中。出于喉咙。以贯心肺而行呼吸焉。营气者秘其津液。注之于脉。化而为血。以营四末。内
注五脏六腑。以应刻数焉。卫气者。出悍气之 疾。而先行于四末分肉之间。行而不休者也。又宗
气之道。内谷为实。谷入于胃。乃传之于脉。流溢于中。布散于外。精专者行于经隧。常营无已。
终而复始。是谓天地之纪。或饮食失常。胃气不能鼓舞。脾气不能运化。行于百脉。其气下流。乘
其肝肾。土木水相合。下疰于足 。 肿而作疼痛。晋苏敬号为香港脚是也。凡治此疾。每旦早饭。
任意饱食。午饭少食。日晚不食。弥佳。恐伤脾胃营运之气。失其天度。况夜食则血气壅滞。而行
阴道。愈增肿痛。古之人少有此疾。自永嘉南渡。衣缨士人多有之。大唐开关。爪牙之士作镇于南
极。其地卑湿。雾露所聚。不袭水土。往者皆遭之。关西河北人。皆不生此疾。外台秘要总录。亦
说江东岭南大率有此。此盖清湿袭虚伤于下。故经云。感则害人皮肉筋骨者也。故制方立论。皆详
其当时土地所宜而治之。今观此方爽
恺。（谓爽明恺燥也。本左传）而无卑湿之地。况腠理致密。外邪难侵。而有此疾者。何也。盖
多饮乳酪醇酒。水湿之属也。加以奉养过度。以滋其湿水之润下。气不能 之。故下疰于足 。积
久而作肿满疼痛。此饮之下流之所致也。岂可与南方之地同法而治哉。当察其地势高下。详其饮食
居处。立为二法。一则治地之湿气。一则治饮食之下流。随其气宜。用药施治。使无疾之苦。庶几
合轩岐之旨哉。孙真人云。医者、意也。随时增损。物无定方。真知言哉。
The *Huangdi Neijing* (Yellow Emperor's Inner Canon) states: When the Taiyang (Greater Yang) qi prevails, fire qi is internally constrained and flows outward to the exterior. The feet swell; fluid retention originates in the middle jiao, causing edema of the head and face. It also states: If the Spleen pulse is firm and long, and the complexion is yellow, one should suffer from shortness of breath (Shaoqi). If the pulse is scattered and the complexion lacks luster, one should suffer from swelling of the lower legs and shins, resembling water disease. In diseases of the Spleen, the body feels heavy, muscles are flaccid and atrophic, the feet cannot walk, diarrhea is frequent, and there is pain under the feet. This occurs because food intake is abundant but qi is deficient, and dampness resides in the lower part. Therefore, dampness enters from below. As mentioned above, this refers to dampness from the Spleen and Stomach flowing downward, attacking the positions of the Liver and Kidney, thereby causing pain and swelling in the lower legs and shins.
When five grains enter the Stomach, dregs, body fluids, and Zong Qi (Gathering Qi) are divided into three pathways. Thus, Zong Qi accumulates in the chest, emerges from the throat, penetrates the Heart and Lungs, and governs respiration. Ying Qi (Nutritive Qi) retains its fluids, injects them into the vessels, transforms into blood, and nourishes the four extremities, internally supplying the Five Zang and Six Fu organs to correspond with the rhythmic flow of time (Ke Shu). Wei Qi (Defensive Qi), derived from the rapid aspect of Han Qi (Pugnacious Qi), moves swiftly ahead between the muscles and skin of the four extremities, moving without rest. Furthermore, the pathway of Zong Qi relies on internal grain for substance. Grain entering the Stomach is transmitted to the vessels, overflowing internally and spreading externally. The pure and concentrated parts travel through the meridians and collaterals, circulating endlessly, ending and beginning again, which is called the principle of Heaven and Earth.
If dietary habits are irregular, Stomach qi fails to inspire, and Spleen qi fails to transform and transport. As qi circulates through the hundred vessels, it flows downward, attacking the Liver and Kidney. Earth, Wood, and Water combine, and dampness descends to the feet, causing swelling and pain. Su Jing of the Jin Dynasty termed this "Hong Kong Jiao" (Hong Kong Foot/Gout). To treat this disease, one may eat until full at breakfast, eat less at lunch, and abstain from dinner, which is optimal. One must fear damaging the transporting and transforming qi of the Spleen and Stomach and violating natural rhythms. Moreover, eating at night causes stagnation of blood and qi, following the Yin path, thereby increasing swelling and pain. Ancient people rarely suffered from this disease. Since the southward migration during the Yongjia era, many scholars and officials have suffered from it. After the founding of the Tang Dynasty, military generals garrisoned the far south. The terrain there is low and damp, with accumulated fog and dew. Those unaccustomed to the local environment would all contract this illness. People from Guanxi and north of the Yellow River do not suffer from this disease. The *Waitai Miyao* (Secret Essentials of the Outer Cabinet) also notes that this disease is prevalent in Jiangdong and Lingnan. This is due to clear dampness invading deficiency in the lower body; thus, the classic states, "Pathogenic invasion damages the skin, flesh, sinews, and bones." Therefore, when formulating prescriptions and establishing theories, one must carefully consider the suitability of the local land and climate for treatment.
Observing the current region (the North), it is crisp and dry, lacking low-lying damp areas. Moreover, the cou li (pores/skin texture) are dense, making external pathogens difficult to invade. Yet some still suffer from this disease. Why? It is likely due to excessive consumption of milk, cheese, and strong wine, which belong to the category of water-dampness. Coupled with excessive indulgence, this nourishes the descending nature of damp-water, while Yang qi fails to control it. Consequently, it descends to the feet, accumulating over time to cause swelling, fullness, and pain. This results from the downward flow of diet. How can it be treated by the same methods as those used in the South? One must examine the elevation of the terrain and inquire in detail about diet and living conditions, establishing two therapeutic approaches: one to treat the dampness of the land, and another to treat the downward flow of diet. Medications should be administered according to the appropriate qi, alleviating the patient's suffering, thereby aligning with the principles of Xuanyuan (Yellow Emperor) and Qibo. Sun Simiao stated: "A physician acts with intention (Yi). Adjustments are made according to circumstances; there are no fixed formulas." These are truly insightful words.