三十五难曰∶五脏各有所，腑皆相近，而心肺独去大肠小肠远者，何也？
然∶经言心荣肺卫，
通行阳气，故居在上；大肠小肠，传阴气而下，故居在下，所以相去而远也。
肝之腑胆，脾之腑胃，肾之腑膀胱，其位皆相近。心之腑小肠，肺之腑大肠，何以皆相远？
盖血为营而心主血，故营属心，气为卫而肺主气，故卫属肺。心荣肺卫，行阳气而居上，大肠
小肠，传阴气而居下，所司不同，其经虽相合，而位则相远矣。
又诸腑者，皆阳也，清净之处。今大肠小肠，胃与膀胱，皆受不净，其意何也？
又问阳宜清净，而诸腑皆阳也，则当为清净之处，然大肠小肠，胃与膀胱，反受秽浊，独不
及胆，何也？盖胆无所受故也。
然∶诸腑者，谓是非也。经言小肠者，受盛之腑也；大肠者，传写行道之腑也；胆者、清净
之腑也；胃者，水谷之腑也；膀胱者，津液之腑也。一腑犹无两名，故
知非也。小肠者，心之腑；大肠者，肺之腑；胆者，肝之腑；胃者，脾之腑；膀胱者，肾之腑。
言诸腑虽属于阳，而非皆清净之腑也。《素问·灵兰秘典论》曰∶小肠者，受盛之官，化物出
焉。盛音承，贮也。言受胃之物，化其渣滓，故云受盛之腑也。又曰∶大肠者，传道之官，变
化出焉。言小肠中物，至此精汁已尽，变化为糟粕而出，故云行道之腑也。又曰∶胆者，中正
之官，决断出焉。胆无受而有泻，故云清净之腑也。又曰∶脾胃者，仓廪之官，五味出焉。言
胃主纳谷，脾主消谷，二者相合，统称仓廪之官，故云水谷之腑也。又曰∶膀胱者，州都之官，
津液藏焉，气化则能出矣。言膀胱之水，能化而为气，由冲任直上，化津化液化汗，故云津液
之腑也。诸腑各有名，如上文所云，皆实指受秽浊者也。盖诸体为阳，而用则为阴，经所谓浊
阴归六腑也。惟胆名清净，故不受秽浊，若余腑亦名清净，则有两名矣。《灵枢·本输篇》曰∶
肺合大肠，心合小肠，肝合胆，脾合胃，肾合膀胱，此其义也。
按∶西医言小肠紧接于胃之下口，由幽门起至阑门止，约长二丈，通体皆是脂膜相连，中有
微丝管，其胆之苦汁，胰之甜汁，均由微丝管注入小肠，化食物，而所化之精汁，由众液管从
膜中吸至颈会管，过肺入心，化赤为血而达各脏。经言小肠者受盛之官，化物出焉者，实指小
肠之气化也。其附小肠之脂膜，即三焦之物，而又属之脾。小肠又系心之腑，其相通之道，即
由微丝管从三焦上膈，至包络而达心，心遗热于小肠，则化物不出，为痢为淋，脾阴不足，则
中焦不能受盛、为膈食便结，三焦相火不足，不能蒸化水谷，则为溏泻矣。大肠由阑门接小肠
起，至肛门止，约长五尺余，小肠中物，至此精汁已尽化，变为糟粕而出。经言大肠者传道之
官，变化出焉者，指大肠能传道糟粕也。然大肠所以能传道者，以其为肺之腑，肺气下达，故
能传道，是以大便秘结，有升举肺气之法也。胆附肝右叶之旁，中贮苦汁，其汁乃下部回血入
肝所化，人食后小肠饱满，上逼胆囊，使其汁流入小肠之内，以榨化食物而利传渣滓，此西医
之言也。不知胆汁色青而属阳，本得肝阴所生之气化，有是气乃有是汁耳。若以汁论，胆汁多
者，胆大而无畏惧；若以气论，则胆火旺者，亦无畏惧。太过者，不得乎中，则失其正，故有
敢为横暴之事；不及者，不得乎中，则失其正，故常存惧怯之心。经言胆者中正之官，决断出
焉。谓气不刚不柔，得成中正，而临事自有决断也。以肝胆二者合论，肝之阳，藏于阴，故主
谋；胆之阳，出于阴，故主断。若夫泻而不受，故名清净之腑也。胃居膈下，其形纡曲如
袋，其纹密，故食物易入虽出，上连食管，下接小肠，周遭多细穴，以生津汁，食物经胃津融和，
略似浓粥，即出胃之下口幽门，而至小肠头，与胆之苦青汁，胰之甜白汁会合，榨出精液，经
众液管吸至颈，即过肺入心，化赤为血。胰者，附脾之物，脾统血，胰中之甜白汁，乃脾血得
脾阳之气化而成。经言脾胃者，仓廪之官，五味出焉。盖胃纳谷，脾消谷，二者相合，而后成
功，故可统称仓廪也。然胆汁化食，戴元礼入肝之说，有由来矣。膀胱居两跨骨内正中，即阴
交骨里，体圆如盘，舒缩自如，下口与前阴相连，上口有小孔甚细，为下焦之脂膜遮闭，饮入
之水，由胃下幽门之上小窍，散布下焦网膜，渗入为溺，无溺则缩，溺至则舒，溺多则涨。西
医但知膀胱藏溺，而不知水入膀胱，化气上行，则为津液，所剩余质，乃下出而为溺。经言膀
胱者，州都之官，津液藏焉，气化则能出矣。其言气化则能出者，谓出津液，非出溺也。气化
二字，前于八难肾间动气论中，已约略言之，今再详陈其义。夫气者乃火交于水所化，观十二
辟卦，干阳入坤阴而化为气，气升为云为雨，人与天地参，其阴阳之理一也。盖人心主火，人
鼻吸入之气，乃天阳也，亦属火。从鼻入肺，历心系，引心火，循脊背之膂筋，下入肾系。又
从肾系以达下焦气海。气海者何？即三焦之根，位居脐下，经谓胞室，王清任谓之气府者是也。
凡人吸入之天阳，合心火下至胞室，则蒸动膀胱之水，化气上腾，其气透出膀胱，入于胞室，
上循脐旁，由冲任上膈入肺，而还出于口，随呼而出，上出之气，着漆石则为露珠，在口舌脏
腑之中，则为津液，又外出于皮毛，以薰肤润肌而为汗，所谓气化则津液能出者此也。老人溺
多，化气少而水质多，壮者溺少，化气多而水质少也。吸入从脊，督脉主之，呼出从膈，任脉
主之，吸入阳也，火交于水也，呼出阴也，气即是水也。火不足以蒸水，则津液不升，气不得
化，水不足以济火，则津液干枯，小水不下，故曰膀胱者，津液之腑也。
小肠谓赤肠，大肠谓白肠，胆者谓青肠，胃者谓黄肠，膀胱者谓黑肠，下焦之所治也。
此以五行五脏之色，以分别五腑，皆名为肠，则俱受秽浊，所以明不净之故也，下焦之所治
者，《灵枢·营卫生会篇》曰∶水谷者，常并居于胃中，成糟粕而俱下于大肠，而成下焦，渗而
俱下，济泌别汁，循下焦而渗入膀胱焉。故五腑皆下焦之气所治也。
第三十五难问道：五脏各有其固定的位置，六腑也都彼此相邻，唯独心脏和肺脏距离大肠、小肠很远，这是为什么呢？
回答说：医经中说心主营气，肺主卫气，它们通行阳气，所以位居在上；大肠和小肠负责传导阴气向下，所以位居在下，因此它们之间相距较远。
肝的腑是胆，脾的腑是胃，肾的腑是膀胱，它们的位置都相近。心的腑是小肠，肺的腑是大肠，为什么它们也相距遥远呢？
这是因为血成为营气而由心主宰，所以营气归属于心；气成为卫气而由肺主宰，所以卫气归属于肺。心主营、肺主卫，运行阳气而位居上部，大肠和小肠传导阴气而位居下部，所主管的功能不同，虽然它们的经脉相互络属配合，但位置却相距遥远。
另外，所有的腑都属于阳，应该是清净的地方。现在大肠、小肠、胃和膀胱，都接受不洁净的物质，这是什么意思呢？
又问：阳应当保持清净，既然所有腑都属于阳，那么它们都应当是清净之处，然而大肠、小肠、胃和膀胱反而接受秽浊之物，唯独胆没有这种情况，为什么呢？这是因为胆不接受（饮食糟粕）的缘故。
回答说：这种说法是不对的。医经说：小肠是受盛之腑（接受和容纳食物的腑）；大肠是传写行道之腑（传导排泄废物的腑）；胆是清净之腑；胃是水谷之腑；膀胱是津液之腑。一个腑不可能有两个名称，所以知道之前的说法是错误的。小肠是心的腑；大肠是肺的腑；胆是肝的腑；胃是脾的腑；膀胱是肾的腑。这说明诸腑虽然属于阳，但并非都是清净之腑。《素问·灵兰秘典论》说：小肠是受盛之官，化物出焉。“盛”音同“承”，意为贮存。指接受胃传来的食物，消化其渣滓，所以称为受盛之腑。又说：大肠是传道之官，变化出焉。指小肠中的食物到这里，精微汁液已经吸尽，变化为糟粕排出，所以称为行道之腑。又说：胆是中正之官，决断出焉。胆只排泄而不接受（饮食），所以称为清净之腑。又说：脾胃是仓廪之官，五味出焉。指胃主要纳受谷物，脾主要运化谷物，两者结合，统称为仓廪之官，所以称为水谷之腑。又说：膀胱是州都之官，津液藏焉，气化则能出矣。指膀胱中的水，能够化为气，通过冲脉、任脉直上，化为津液、液化为汗，所以称为津液之腑。各个腑都有特定的名称，如上文所说，都确实是指接受秽浊物质的器官。大概形体属于阳，但功能作用则偏向于阴，医经所谓“浊阴归六腑”。只有胆被称为清净，所以不接受秽浊，如果其余各腑也称为清净，那就有了两个名称了。《灵枢·本输篇》说：肺合大肠，心合小肠，肝合胆，脾合胃，肾合膀胱，这就是其中的道理。
按语：西医认为小肠紧接在胃的下口，从幽门开始到阑门结束，大约长二丈，整个肠道都由脂膜相连，中间有微细血管管，胆汁的苦汁、胰液的甜汁，都通过微细血管管注入小肠，消化食物，而消化后的精微汁液，通过众多液体管从肠膜中吸收至颈部的会合管，经过肺进入心脏，化为红色的血液输送到各个脏腑。医经说小肠是受盛之官，化物出焉，实际上是指小肠的气化功能。附着在小肠上的脂膜，就是三焦的物质，同时又归属于脾。小肠又是心的腑，它们相通的途径，就是通过微细血管管从三焦向上穿过膈肌，到达心包络进而通达心脏，如果心将热邪遗留给小肠，就会导致食物不能正常转化，出现痢疾或淋证；如果脾阴不足，中焦就不能正常受盛，导致噎膈和便秘；如果三焦相火不足，不能蒸腾气化水谷，就会导致溏泄。大肠从阑门连接小肠开始，直到肛门结束，大约长五尺多，小肠中的食物到这里，精微汁液已经完全化尽，变为糟粕排出。医经说大肠是传道之官，变化出焉，是指大肠能够传导糟粕。但是大肠之所以能够传导，是因为它是肺的腑，肺气下达，所以能够传导，因此大便秘结时，有升举肺气的治疗方法。胆附着在肝脏右叶旁边，里面储存苦汁，这苦汁是由下部回流血液进入肝脏所化生，人进食后小肠饱满，向上压迫胆囊，使其汁液流入小肠内部，以榨取消化食物并利于传输渣滓，这是西医的说法。却不知道胆汁颜色青而属性为阳，本来是由肝阴所生的气化功能产生的，有了这种气化才有这种汁液。如果从汁液来看，胆汁多的人，胆子大而没有畏惧；如果从气化功能来看，胆火旺盛的人，也没有畏惧。如果太过分，就不能保持中正，就会失去正道，所以会有敢作横暴之事；如果不及，也不能保持中正，就会失去正道，所以常存有恐惧怯懦之心。医经说胆是中正之官，决断出焉，意思是气既不刚也不柔，达到中正状态，面对事情自然就有决断力。如果把肝胆两者结合起来论述，肝的阳气藏于阴中，所以主谋划；胆的阳气出于阴外，所以主决断。至于只排泄而不接受，所以称为清净之腑。胃位于膈肌下方，形状弯曲像袋子，纹理密集，所以食物容易进入也容易出来，上连食管，下接小肠，周围有很多细小的孔穴，用来生津液，食物经过胃津的融化和调和，略微像浓粥一样，就从胃的下口幽门出来，到达小肠头部，与胆汁的青苦汁、胰液的甜白汁汇合，榨取精液，经过众多液体管吸收至颈部，即经过肺进入心脏，化为红色血液。胰是附着在脾上的器官，脾统摄血液，胰中的甜白汁，是脾血得到脾阳气化而成的。医经说脾胃是仓廪之官，五味出焉。大概胃纳受谷物，脾运化谷物，两者结合，然后才能成功，所以可以统称为仓廪。然而胆汁消化食物，戴元礼提出的入肝之说，是有来源的。膀胱位于两胯骨内正中，即阴交骨里面，身体圆润如盘，舒缩自如，下口与前阴相连，上口有一个非常细小的孔，被下焦的脂膜遮蔽关闭，喝进去的水，从胃下幽门上方的小窍散布到下焦网膜，渗入成为尿液，没有尿时就收缩，尿满了就舒展，尿多了就涨大。西医只知道膀胱储存尿液，而不知道水进入膀胱后，化为气上行，就成为津液，所剩余的残渣物质，才向下排出成为尿液。医经说膀胱是州都之官，津液藏焉，气化则能出矣。其中说“气化则能出”，是指出津液，而不是指出尿液。“气化”二字，在前面第八难关于肾间动气的论述中，已经大致提及，现在再详细阐述其含义。所谓气，是火与水相交所化生的，观察十二辟卦，乾阳进入坤阴而化为气，气上升成为云雨，人与天地参赞，其中的阴阳道理是一致的。大概人心主火，人鼻吸入的空气，是天阳之气，也属于火。从鼻子进入肺，经过心系，引动心火，沿着脊柱背部的筋，向下进入肾系。又从肾系到达下焦气海。气海是什么？就是三焦的根本，位置在脐下，医经称为胞室，王清任称为气府的是这个部位。凡人吸入的天阳之气，与心火一起下降到胞室，则蒸动膀胱中的水，化为气向上腾升，这股气透出膀胱，进入胞室，向上沿着脐旁，通过冲脉、任脉上穿膈肌进入肺，然后从口中呼出。呼出的气体，接触到冰冷的石头就会凝结成露珠，在口腔、舌头和脏腑之中，就成为津液，又向外出于皮毛，熏蒸皮肤、滋润肌肉成为汗，所谓“气化则津液能出”就是这个意思。老人小便多，是因为化气少而水质多；壮年人小便少，是因为化气多而水质少。吸入之气走脊柱，由督脉主导；呼出之气走胸膈，由任脉主导。吸入属于阳，是火与水交；呼出属于阴，气即是水。火不足以蒸腾水，则津液不升，气无法化生；水不足以济助火，则津液干枯，小便不下，所以说膀胱是津液之腑。
小肠称为赤肠，大肠称为白肠，胆称为青肠，胃称为黄肠，膀胱称为黑肠，这些都是下焦所治理的范围。这里用五行和五脏的颜色来分别五个腑，都称为肠，说明它们都接受秽浊之物，以此来阐明不洁净的原因。下焦所治理的，《灵枢·营卫生会篇》说：水谷，常常共同居住在胃中，形成糟粕并且一起下行到大肠，从而构成下焦，渗透过滤并分别汁液，顺着下焦渗入膀胱。所以五个腑都是由下焦的气所治理的。
Chapter 35 states: The five Zang organs each have their specific locations, and the six Fu organs are all close to one another. Why are the Heart and Lung located far from the Large Intestine and Small Intestine?
The response is: The classics state that the Heart governs Ying (Nutritive Qi) and the Lung governs Wei (Defensive Qi). They circulate Yang Qi, therefore they reside in the upper part of the body. The Large Intestine and Small Intestine transmit Yin Qi downward, therefore they reside in the lower part. This is why they are distant from each other.
The Gallbladder is the Fu organ of the Liver; the Stomach is the Fu organ of the Spleen; the Bladder is the Fu organ of the Kidney. Their positions are all close to each other. However, the Small Intestine is the Fu organ of the Heart, and the Large Intestine is the Fu organ of the Lung. Why are these also distant from each other?
This is because blood becomes Ying Qi and is governed by the Heart, so Ying Qi belongs to the Heart. Qi becomes Wei Qi and is governed by the Lung, so Wei Qi belongs to the Lung. The Heart governs Ying and the Lung governs Wei; they circulate Yang Qi and reside in the upper part. The Large Intestine and Small Intestine transmit Yin Qi and reside in the lower part. Since their functions differ, although their meridians are internally-externally paired, their physical locations are distant.
Furthermore, all Fu organs belong to Yang and should be places of purity. Now, the Large Intestine, Small Intestine, Stomach, and Bladder all receive impure substances. What is the meaning of this?
Another question arises: Yang should remain pure. Since all Fu organs belong to Yang, they should all be places of purity. Yet the Large Intestine, Small Intestine, Stomach, and Bladder accept turbid and filthy substances, while only the Gallbladder does not. Why? This is because the Gallbladder receives nothing [from food].
The response is: That assertion is incorrect. The classics state: The Small Intestine is the Fu organ of receiving and storing (Shou Sheng); the Large Intestine is the Fu organ of transmission and passage; the Gallbladder is the Fu organ of purity; the Stomach is the Fu organ of water and grain; the Bladder is the Fu organ of Jin-Ye (Body Fluids). One Fu organ cannot have two names, thus we know the previous assertion is wrong. The Small Intestine is the Fu organ of the Heart; the Large Intestine is the Fu organ of the Lung; the Gallbladder is the Fu organ of the Liver; the Stomach is the Fu organ of the Spleen; the Bladder is the Fu organ of the Kidney. This indicates that although all Fu organs belong to Yang, they are not all Fu organs of purity. *Su Wen · Ling Lan Mi Dian Lun* states: "The Small Intestine is the official of receiving and storing, from which transformation occurs." 'Sheng' sounds like 'Cheng', meaning storage. It refers to receiving what comes from the Stomach and transforming its dregs, hence called the Fu organ of receiving and storing. It further states: "The Large Intestine is the official of transmission, from which changes occur." It means that when food from the Small Intestine arrives here, the essence has been fully absorbed, and it transforms into waste for excretion, hence called the Fu organ of passage. It further states: "The Gallbladder is the official of uprightness, from which decision-making emerges." The Gallbladder only excretes and does not receive [food], hence called the Fu organ of purity. It further states: "The Spleen and Stomach are the officials of the granary, from which the five flavors emerge." This means the Stomach primarily receives grain, and the Spleen primarily transforms grain. Together, they are collectively called the officials of the granary, hence called the Fu organ of water and grain. It further states: "The Bladder is the official of the provincial capital, where Jin-Ye are stored; through Qi transformation, they can be excreted." This means the water in the Bladder can transform into Qi, rising directly via the Chong and Ren meridians, transforming into Jin-Ye, fluids, and sweat, hence called the Fu organ of Jin-Ye. Each Fu organ has a specific name as mentioned above, all truly referring to organs that receive turbid substances. Generally, the form is Yang, but its function is Yin, as the classics say, "Turbid Yin returns to the Six Fu organs." Only the Gallbladder is named pure, thus it does not receive turbidity. If the other Fu organs were also named pure, they would have two names. *Ling Shu · Ben Shu* states: "The Lung pairs with the Large Intestine, the Heart pairs with the Small Intestine, the Liver pairs with the Gallbladder, the Spleen pairs with the Stomach, the Kidney pairs with the Bladder." This is the principle.
Commentary: Western medicine states that the Small Intestine is tightly connected below the lower opening of the Stomach, starting from the pylorus to the ileocecal valve, approximately two zhang long. The entire intestine is connected by fatty membranes, containing microscopic vessels. The bitter juice of the gallbladder and the sweet juice of the pancreas are injected into the Small Intestine via these microscopic vessels to digest food. The digested essence is absorbed from the intestinal membrane into the venous confluence in the neck, passes through the Lungs into the Heart, turns red to become blood, and reaches various organs. When the classics say the Small Intestine is the official of receiving and storing, transforming things out, it actually refers to the Qi transformation of the Small Intestine. The fatty membrane attached to the Small Intestine is the substance of San Jiao (Triple Burner), and it also belongs to the Spleen. The Small Intestine is also the Fu organ of the Heart. The pathway of connection is through the microscopic vessels from San Jiao, upward through the diaphragm, to the Pericardium and then to the Heart. If Heart heat is transmitted to the Small Intestine, transformation fails, leading to dysentery or strangury. If Spleen Yin is insufficient, the Middle Jiao cannot receive and store properly, leading to dysphagia and constipation. If San Jiao Ministerial Fire is insufficient to steam and transform water and grain, loose stools result. The Large Intestine connects to the Small Intestine at the ileocecal valve and ends at the anus, approximately five chi long. By the time food from the Small Intestine reaches here, the essence has been fully transformed, becoming waste for excretion. When the classics say the Large Intestine is the official of transmission, changing things out, it refers to the Large Intestine's ability to transmit waste. However, the reason the Large Intestine can transmit is because it is the Fu organ of the Lung; Lung Qi descends, enabling transmission. Therefore, for constipation, there are methods to lift Lung Qi. The Gallbladder is attached beside the right lobe of the Liver, storing bitter juice. This juice is transformed from blood returning from the lower body entering the Liver. After eating, the full Small Intestine presses upward on the Gallbladder, causing its juice to flow into the Small Intestine to squeeze and digest food and facilitate the transmission of dregs. This is the Western medical view. However, one does not know that bile is green and belongs to Yang, originally generated by the Qi transformation of Liver Yin. With this Qi transformation, there is this juice. If judging by juice, those with more bile have courage and no fear. If judging by Qi, those with vigorous Gallbladder Fire also have no fear. If excessive, one loses balance and uprightness, leading to reckless behavior. If deficient, one loses balance and uprightness, leading to constant fearfulness. The classics say the Gallbladder is the official of uprightness, from which decision-making emerges. This means if Qi is neither too rigid nor too soft, achieving uprightness, one naturally has decision-making ability when facing matters. Discussing Liver and Gallbladder together: Liver Yang hides within Yin, thus governing planning; Gallbladder Yang emerges from Yin, thus governing decision-making. As for only excreting and not receiving, it is named the Fu organ of purity. The Stomach is located below the diaphragm, curved like a bag with dense folds, so food enters and exits easily. It connects superiorly to the esophagus and inferiorly to the Small Intestine. Surrounding it are many fine pores to generate fluid. Food mixed with Stomach fluid resembles thick porridge before exiting the pylorus to the head of the Small Intestine, meeting the green-bitter bile and white-sweet pancreatic juice to extract essence. This essence is absorbed via vessels to the neck, passes through the Lungs into the Heart, turns red to become blood. The Pancreas is an organ attached to the Spleen. The Spleen governs blood. The sweet-white juice in the Pancreas is formed by Spleen blood undergoing Spleen Yang Qi transformation. The classics say the Spleen and Stomach are the officials of the granary, from which the five flavors emerge. Essentially, the Stomach receives grain, the Spleen transforms grain; together they succeed, hence collectively called the granary. However, the theory that bile digestion enters the Liver, proposed by Dai Yuanli, has its origins. The Bladder is located in the center inside the hip bones, within the pubic symphysis. Its body is round like a plate, expanding and contracting freely. The lower opening connects to the external genitalia; the upper opening has a very fine hole covered by the Lower Jiao fatty membrane. Water drunk spreads from the small aperture above the pylorus of the Stomach into the Lower Jiao omentum, infiltrates to become urine. Without urine, it shrinks; with urine, it expands; with much urine, it swells. Western medicine only knows the Bladder stores urine, but does not know that water entering the Bladder transforms into Qi ascending to become Jin-Ye, while the remaining residue is excreted downward as urine. The classics say the Bladder is the official of the provincial capital, where Jin-Ye are stored; through Qi transformation, they can be excreted. "Through Qi transformation, they can be excreted" refers to the excretion of Jin-Ye, not urine. The term "Qi transformation" was briefly discussed in Chapter 8 regarding Kidney Interstitial Moving Qi; now its meaning is detailed. Qi is transformed from Fire interacting with Water. Observing the twelve辟卦 (Pi Gua), Qian Yang enters Kun Yin to transform into Qi. Qi rises to become clouds and rain. Humans participate with Heaven and Earth; the principle of Yin and Yang is the same. The Human Heart governs Fire. Air inhaled through the nose is Heavenly Yang Qi, also belonging to Fire. Entering the nose into the Lungs, passing through the Heart system, drawing Heart Fire, following the muscles along the spine, descending into the Kidney system. From the Kidney system, it reaches the Qi Sea of the Lower Jiao. What is the Qi Sea? It is the root of San Jiao, located below the umbilicus. The classics call it the Bao Shi (Uterus/Womb), and Wang Qingren calls it the Qi Fu (Qi Mansion). The Heavenly Yang Qi inhaled by humans combines with Heart Fire descending to the Bao Shi, steaming the water in the Bladder, transforming it into Qi rising upward. This Qi penetrates the Bladder, enters the Bao Shi, ascends along the side of the umbilicus, goes up through the Chong and Ren meridians through the diaphragm into the Lungs, and returns out through the mouth with exhalation. Exhaled gas condensing on cold stone becomes dewdrops; in the mouth, tongue, and internal organs, it becomes Jin-Ye; externally exiting the skin and hair, it steams the skin and moistens muscles to become sweat. This is what is meant by "through Qi transformation, Jin-Ye can be excreted." The elderly urinate frequently because they transform little Qi and have much water quality; the vigorous young urinate less because they transform much Qi and have little water quality. Inhaled air follows the spine, governed by the Du Meridian; exhaled air follows the diaphragm, governed by the Ren Meridian. Inhalation is Yang, Fire interacting with Water; exhalation is Yin, Qi being Water. If Fire is insufficient to steam Water, Jin-Ye does not rise, Qi cannot transform. If Water is insufficient to assist Fire, Jin-Ye dries up, and small urination does not descend. Thus, it is said the Bladder is the Fu organ of Jin-Ye.
The Small Intestine is called the Red Intestine, the Large Intestine the White Intestine, the Gallbladder the Green Intestine, the Stomach the Yellow Intestine, and the Bladder the Black Intestine. These are governed by the Lower Jiao. Here, using the colors of the Five Elements and Five Zang organs to distinguish the five Fu organs, all are named Intestines, indicating they all receive turbid substances, thereby clarifying the reason for impurity. Regarding what is governed by the Lower Jiao, *Ling Shu · Ying Wei Hui Sheng Pian* states: "Water and grain often reside together in the Stomach, forming dregs and descending together to the Large Intestine, constituting the Lower Jiao. They filter and separate juices, following the Lower Jiao to infiltrate the Bladder." Therefore, all five Fu organs are governed by the Qi of the Lower Jiao.