按香港脚之病，自古无有称之。自晋苏敬始，其头痛寒热类伤寒，而病起足膝肿病，则与
伤寒异
。其逆气上行，类风厥而痛甚，乃至闷倒，则与风厥异。其两足软弱，类痿痹而时发时止，
痛惟在足，则与痿之一废不复，痹之无定所者异。致此之由，多因美饮醇醪，上承湿热之下
注，蹈寒涉水，下吸清湿之上升，两者交成，故名壅疾。自东垣有南方香港脚，外感清湿作
寒治；北方香港脚，内伤酒乳作湿热治之论。致使后人泥之，遂成南北两派。互相拘执，不知
北方纵无地之卑湿，其冒雨露，履汗 ，与夫脱卸靴履，汗出而风吹之，致血凝于足，岂不
与南
方卑湿同类，尽属外中者乎？南方纵无潼乳之湿，其酒食过多，与脏腑所传，津液水谷停积
于中而下注者，岂不与北方潼乳之湿同类，尽属内伤者乎？学人苟能圆通活变，斯万举万当
矣。
至直大要论列病机一十九条，而遗漏燥证，为其兼乎风热之化，故但言风热而燥在其中
矣。
河间特补此义于《原病式》中，然义有未悉，敢再陈之。夫燥兼风化者，经云∶风能胜湿，
湿去则燥自生，始因风甚而燥及于肺，则木气有余，侮所不胜，而金更微邪。复因燥甚而病
及乎肝，则木气亢害，承者制之，而金行报复，故筋脉劲强，口噤风痫，皮肤燥屑，收敛急
切之病生矣。燥兼热化者，热即火也。易曰∶燥万物者，莫 乎火。始由真阴耗竭，致有克
金之火，而燥乃成。金受邪，不能生制火之水，而燥益甚，故消谷善饥，噎膈胃枯。二便闭
塞，燥烈枯涸等证生矣。由热生风，由风生燥，燥又生热，循环胜复。至于髓液咸枯，燥非
浅患明矣。臻燥之因，或遇阳胆司天，燥化大行；或久劳于风日之中，频迩于火燥之畔，外
因也。七情不节，神伤血耗，及大病吐汗下克伐太过，亡其津液，内因也。食味辛热过多，
虚劳误投温补，与夫服食家金石之剂发燥，不内外因也。凡此诸论，皆令热极生风，风火相
煽，阴中伏火，煎熬津液，而燥证深矣。是以燥在外，皮肤皱揭，疥痒爪枯；燥在中，脾胃
干涸，消谷善饥；燥在上，则鼻燥咽干；燥在下，则便难癃闭；兼热，则手足痿；兼风，则
痉痫作。虚而燥热，必致劳咳；实而燥热，必见癫狂；挟痰食者，终为噎膈等证。治燥之法
，当观沸釜之理，以血喻汤，而气喻火也。若火猛汤沸，当沃薪灭火，不使绝竭，犹用芩连
、栀、膏、朴硝、大黄，大苦至寒治标等剂，清降火邪，则血不为衰，而燥不为甚也。若沸
久将干，又将添益新水，使能胜火，犹用地黄、门冬、参、 、归、芍，甘寒甘温，治本之
剂，气血双补，则燥得所润，而火有所制也。昔贤云∶休治风，休治燥，治得火时风燥了，
然
则独无寒燥者乎？尝考《医垒元戎》，有五方治燥诸法元∶北方其脉迟，寒燥也，宜温热药
治之，如桂、附、硫黄、良姜、巴豆之属，是知燥亦兼寒。张景岳论消渴亦云∶阳胜固能消
阴，阴胜独不能消阳乎？经云∶移寒于肺为肺消，饮一溲二死，不治之证，曾以八味丸、归
脾汤，治一缙绅得愈。又如大便燥结，有系脏寒则血枯，脏冷则气涩，食少脉微为阴结者，
宜半硫丸、香附汤治之。夫消渴闭结，燥证之大者，乃有属于阴寒，海藏非凿说矣。知常识
变，圆妙无穷，始得不愧为司命。
关于香港脚（一种以足部肿痛、软弱或麻木为主要表现的疾病）这一病症，自古以来并没有专门的称呼。自晋代苏敬开始记载，其症状表现为头痛、恶寒发热，类似伤寒，但病起于足膝肿胀疼痛，这与伤寒不同。若气逆上行，类似风厥且疼痛剧烈，甚至导致昏厥倒地，这又与风厥不同。若双足软弱无力，类似痿痹且时发时止，疼痛仅局限于足部，这与痿证一旦发作便废用不复、痹证疼痛部位不固定的情况也不同。导致此病的原因，多因饮用美酒醇酿，使湿热上承并下注；或因踏寒涉水，使清湿之气从下上升。内外湿气交结，因此称为“壅疾”。
自李东垣提出南方香港脚因外感清湿而按寒证治疗，北方香港脚因内伤酒乳而按湿热证治疗的理论后，致使后人拘泥于此，形成了南北两派。他们互相固执己见，却不知北方即使没有地势低洼潮湿的环境，人们冒雨淋露、踩踏汗水，以及脱卸靴鞋时汗出受风吹，导致血液凝滞于足部，这难道不与南方的卑湿环境同类吗？这些都应属于外邪侵袭所致。南方即使没有潼乳（可能指某种乳制品或特定食物）的湿气，但若饮食过多，加之脏腑传变，津液和水谷停积于中焦而下注，这难道不与北方的潼乳之湿同类吗？这些都应属于内伤所致。学者若能圆通灵活地运用这些理论，那么处理万种情况都能得当。
至于《素问·至真要大论》列举了十九种病机，却遗漏了燥证，这是因为燥常兼夹风热之化，所以只说风热而燥在其中了。刘河间特别在《原病式》中补充了这一义理，然而其中含义仍有未详尽之处，我斗胆再次陈述。所谓燥兼风化，经书云：“风能胜湿”，湿气去除则燥自然产生。起初因风邪甚盛而燥气波及肺脏，导致木气有余，侮其所不胜（金），使得金气更微弱的邪气所伤。随后因燥气甚盛而病及肝脏，导致木气亢盛为害，承制者对其进行制约，金行进行报复，因此出现筋脉劲强、口噤、风痫、皮肤干燥起屑、收敛急切等病症。
所谓燥兼热化，热即火。《易经》云：“燥万物者，莫熯乎火。”起初由真阴耗竭，导致克制金的火势旺盛，从而形成燥证。金受邪后，不能生制火的肾水，使得燥更加严重，因此出现消谷善饥、噎膈、胃枯、二便闭塞、燥烈枯涸等症状。由热生风，由风生燥，燥又生热，循环往复。到了髓液枯竭，说明燥并非浅表的小病。导致燥的原因，有的是遇到阳明燥金司天，燥气化大行；有的是长期劳累于风日之中，频繁接近火燥之地，这是外因。七情不节制，神伤血耗，以及大病时吐、汗、下法攻伐太过，亡失津液，这是内因。食用辛辣热性食物过多，虚劳误用温补，以及服食金石类药物引发燥证，这是不内外因。以上各种论述，都会导致热极生风，风火相煽，阴中伏火，煎熬津液，从而使燥证加深。
因此，燥在体表，则皮肤皱裂、疥痒、指甲枯槁；燥在中焦，则脾胃干涸、消谷善饥；燥在上焦，则鼻燥咽干；燥在下焦，则大便困难、小便癃闭；兼有热邪，则手足痿软；兼有风邪，则痉病、痫病发作。虚而燥热，必致劳嗽咳嗽；实而燥热，必见癫狂；挟带痰食的，最终成为噎膈等证。治疗燥证的方法，应当观察沸腾锅釜的道理，以血比喻汤水，以气比喻火焰。如果火猛汤沸，应当加水灭火，不让水分绝竭，犹如使用黄芩、黄连、栀子、石膏、朴硝、大黄等大苦大寒的药物作为治标的方剂，清降火邪，那么血液就不会衰败，燥也不会加重。如果煮沸时间过长即将干涸，又应当添加新水，使其能胜过火势，犹如使用地黄、麦冬、人参、白术、当归、芍药等甘寒、甘温的药物作为治本的方剂，气血双补，那么燥得到滋润，火得到制约。
昔日贤人说：“不要治风，不要治燥，治好火的时候，风和燥也就好了。”然而难道就没有寒燥吗？我曾考察《医垒元戎》，其中有五种治疗燥证的方法：北方脉迟，属于寒燥，宜用温热药治疗，如桂枝、附子、硫黄、良姜、巴豆之类，由此可知燥也兼夹寒邪。张景岳讨论消渴症时也说过：阳胜固然能消阴，阴胜难道就不能消阳吗？经书云：“移寒于肺为肺消”，饮水一升，排尿二升，是死证，不治之症，但我曾用八味丸、归脾汤治愈了一位官员。又如大便燥结，有的因为脏寒导致血枯，脏冷导致气涩，食少脉微属于阴结的，宜用半硫丸、香附汤治疗。像消渴和大便秘结，是燥证中较大的类型，竟然有属于阴寒的，海藏（张元素）的说法并非穿凿附会。懂得常识并灵活变通，奥妙无穷，才能不愧为掌管人生命运的大夫。
Regarding the disease known as "Hongxiang Jiao" (a condition characterized by swelling, pain, weakness, or numbness in the feet), there was no specific name for it since ancient times. It was first recorded by Su Jing of the Jin Dynasty. Its symptoms include headache, aversion to cold, and fever, resembling Taiyang Bing (Taiyang Disease) [Taiyang Disease: a syndrome caused by pathogenic factors affecting the Taiyang meridian], but the illness originates with swelling and pain in the feet and knees, which differs from Taiyang Bing. If rebellious Qi moves upward, resembling Feng Jue (Wind Reversal) [Wind Reversal: a condition where Qi rebels upward causing dizziness or fainting] with severe pain, even leading to syncope, this differs from Wind Reversal. If both legs are weak and flaccid, resembling Wei Bi (Flaccidity and Obstruction) [Flaccidity and Obstruction: syndromes involving muscle weakness and painful obstruction], with intermittent onset and pain confined only to the feet, this differs from Wei Syndrome (which leads to permanent disability once manifested) and Bi Syndrome (where pain location is不定/unfixed). The cause of this disease often stems from consuming rich wines and liquors, allowing damp-heat to ascend and then descend; or from treading on cold water and mud, allowing clear dampness to rise from below. When these two types of dampness interact, it is named Yong Ji (Stagnation Disease) [Stagnation Disease: a disease caused by pathological stagnation].
Since Li Dongyuan proposed that Southern Hongxiang Jiao, caused by external invasion of clear dampness, should be treated as a cold pattern, while Northern Hongxiang Jiao, caused by internal injury from wine and dairy, should be treated as a damp-heat pattern, later practitioners became rigidly attached to these views, forming Northern and Southern schools. They held conflicting执念 (obsessions), failing to realize that even if the North lacks low-lying damp terrain, exposure to rain and dew, stepping in sweat, or removing boots/shoes while sweating and being exposed to wind can cause blood coagulation in the feet. Is this not similar to the dampness of the South? All such cases belong to external invasion. Even if the South lacks dampness from dairy products, excessive food intake combined with transmission from Zang-Fu organs, where fluids and grain residues accumulate in the middle and descend, is this not similar to the dampness of the North? All such cases belong to internal injury. If scholars can apply these principles flexibly and comprehensively, they will handle ten thousand situations correctly.
As for the *Zhi Yao Da Yao Lun* (Treatise on the Great Essentials of Direct Principles) listing nineteen pathogenesis mechanisms, it omitted Dryness (Zao) patterns because Dryness often combines with Wind-Heat transformation. Thus, it only mentioned Wind-Heat, implying Dryness within it. Liu Hejian specifically supplemented this meaning in his work *Yuan Bing Shi* (Original Causes of Diseases), yet the meanings were not fully elucidated. I dare to elaborate further. Regarding Dryness combining with Wind transformation: The Classics state, "Wind can overcome Dampness; when Dampness is removed, Dryness naturally arises." Initially, excessive Wind causes Dryness to affect the Lung (Metal), resulting in excess Wood Qi insulting its unconquered element (Metal), making Metal more susceptible to evil. Subsequently, excessive Dryness affects the Liver (Wood), causing Wood Qi to become hyperactive and harmful. The controlling element (Metal) retaliates against the excess Wood. Consequently, symptoms such as stiff sinews and tendons, trismus (lockjaw), wind-induced epilepsy, dry scaly skin, and rapid contraction arise.
Regarding Dryness combining with Heat transformation: Heat is Fire. The *I Ching* states, "Nothing dries things more than Fire." Initially, depletion of True Yin leads to Fire that overcomes Metal, forming Dryness. Once Metal is diseased, it cannot generate Water to control Fire, exacerbating Dryness. Symptoms include polyphagia (excessive hunger), dysphagia (difficulty swallowing), gastric dryness, constipation, urinary retention, and signs of intense dryness and withering. Heat generates Wind, Wind generates Dryness, and Dryness generates Heat, creating a cycle of mutual overcoming and retaliation. When marrow and fluids are completely depleted, it is evident that Dryness is not a minor ailment.
Causes of Dryness include: External factors such as Yangming Dryness Metal ruling the year with strong Dryness transformation; or prolonged labor under wind and sun, frequently near fire and dryness. Internal factors include unregulated Seven Emotions, damaging Spirit and depleting Blood; or excessive purging, sweating, and vomiting during serious illnesses, leading to loss of body fluids. Neither-internal-nor-external factors include excessive consumption of pungent and hot foods, inappropriate use of warming tonics for deficiency-wasting diseases, or taking mineral medicines that induce Dryness. All these theories lead to extreme Heat generating Wind, Wind and Fire fanning each other, latent Fire within Yin, and boiling body fluids, deepening the Dryness pattern.
Therefore, Dryness on the exterior causes wrinkled skin, itching, sores, and brittle nails; Dryness in the Middle Jiao causes dry Spleen and Stomach and polyphagia; Dryness in the Upper Jiao causes nasal dryness and throat dryness; Dryness in the Lower Jiao causes difficult defecation and urinary retention. Combined with Heat, it causes flaccidity of hands and feet; combined with Wind, it causes spasms and epilepsy. Deficiency with Dry-Heat leads to consumptive cough; Excess with Dry-Heat leads to mania; with Phlegm and Food retention, it leads to dysphagia. The method for treating Dryness should observe the principle of a boiling cauldron: Blood is like the soup/water, Qi is like the fire. If the fire is fierce and the soup boils vigorously, one must add water to extinguish the fire to prevent exhaustion. This is akin using bitter-cold herbs like Huang Qin (Scutellariae Radix), Huang Lian (Coptidis Rhizoma), Zhi Zi (Gardeniae Fructus), Shi Gao (Gypsum Fibrosum), Pu Xiao (Natrii Sulfas), and Da Huang (Rhei Radix et Rhizoma) as symptomatic treatments to clear and descend Fire, preventing Blood from weakening and Dryness from worsening. If the pot has boiled for too long and is nearly dry, one must add fresh water to overcome the fire. This is akin using sweet-cold and sweet-warm herbs like Di Huang (Rehmanniae Radix), Mai Dong (Ophiopogonis Radix), Ren Shen (Ginseng Radix), Bai Zhu (Atractylodis Macrocephalae Rhizoma), Dang Gui (Angelicae Sinensis Radix), and Bai Shao (Paeoniae Radix Alba) as root treatments to tonify Qi and Blood, moistening Dryness and restraining Fire.
Ancient sages said, "Do not treat Wind, do not treat Dryness; when you treat Fire, Wind and Dryness are resolved." However, are there no Cold-Dryness patterns? I examined *Yi Lei Yuan Rong*, which lists five methods for treating Dryness: In the North, the pulse is slow, indicating Cold-Dryness, suitable for warm-hot herbs like Gui Zhi (Cinnamomi Ramulus), Fu Zi (Aconiti Lateralis Radix Praeparata), Liu Huang (Sulfur), Gao Liang Jiang (Galangal Rhizome), and Ba Dou (Crotonis Fructus). Thus, Dryness also combines with Cold. Zhang Jingyue discussed Xiao Ke (Wasting-Thirst) saying: "If Yang prevails, it consumes Yin; can Yin prevailing not consume Yang?" The Classics state: "Transferring Cold to the Lung creates Lung Xiao (Lung Wasting-Thirst); drinking one unit and urinating two units is a fatal, untreatable condition." Yet, I used Ba Wei Wan (Eight-Ingredient Pill) and Gui Pi Tang (Restore the Spleen Decoction) to cure an official. Similarly, for dry fecal impaction, some cases stem from Zang Cold causing Blood枯 (withering) and Qi stagnation due to cold, presenting with poor appetite and faint pulse, classified as Yin Constipation. These are treated with Ban Liu Wan (Half-Sulfur Pill) or Xiang Fu Tang (Cyperus Decoction). Since Xiao Ke and constipation are major Dryness patterns, and some belong to Yin-Cold, Hai Zang's (Zhang Yuansu's) statements are not far-fetched. Understanding common sense and adapting flexibly leads to infinite subtlety, ensuring one does not fail in their duty as a guardian of life.