三十三难曰∶“肝青象木，肺白象金。肝得水而沉，木得水而浮；肺得水而浮，金得水而沉，其意何也
？”答词以五音刚柔吸受云云，是启后学要识五行造化之妙，而注者又以长生临官帝旺为言，而不就肝肺上
究竟其说，似训释太深，玄之又玄者也。物物具五行，如注所云，心脾肾得水皆沉，不知又当何解。据愚见，
不若平平讲去，亦自明畅，且又开发后学，阴阳相感之义，虽不明言，而理实寓焉。盖肺虽属金，而位处膈
上，行阳道多，且其经为手太阴，主乎气。以体而言，
金也；以用而言，气也。而又属手经，故浮。肺熟则手经之气去，而金之体独存，故熟则沉也。肝虽属木，
而位处膈下，行阴道多，且其经为足厥阴，主乎血。以体而言，木也；以用而言，血也。而又属足经，故沉。
肝熟则足经之血去，而木之体独存，故熟则浮也。返本之义也。临官帝旺之说，微觉牵合，学人详之。
生生子曰∶七十五难云∶“经言东方实，西方虚，泻南方，补北方，何谓也云云，故泻火补水，欲令金
不得平木也。经曰∶不能治其虚，何问其余，此之谓也。”滑伯仁曰∶“不”字疑衍。四明陈氏曰∶仲景云
∶木行乘金，曰横。《内经》曰∶“气有余，则制己所胜，而侮所不胜。”木实金虚，是木横而凌金，侮所
不胜也。木实本以金平之，然以其气正强而横，金平之则两不相伏而战，战则实者亦伤，虚者亦败。金虚本
资气于土，然其时土亦受制，未足以资之。故取水为金之子，又为木之母，于是泻火补水，使水胜火，则火
馁而取气于木，木乃减而不复实，水为木母，此母能令子虚也。木既不实，其气乃平，平则金免木凌，而不
复虚，水为金子，此子能令母实也。所谓金不得平木，不得径以金平其木，必泻火补水而旁治之，使木金之
气自然
而平耳。而滑伯仁又曰∶陈氏之说，亦自有理，但为“不”之一字缠扰，牵强费辞，不若直以“不”字为衍
文尔。余曰∶“不”字非衍，《难经》所谓不者，乃姑息之谓，不径以金平木，故有泻火补水之治，观越人
谓“金木水火土，当更相平”。“更”字与“不”字，乃一篇之大关键也。此更字与二十难更相乘，更相伏
“更”字义同，谓互相平制，不直令金以平木也。观仲景木行乘金曰横之“横”字，则知金非等闲之虚，即
骤补之，犹未能自保，况欲令其得平木乎？彼金之得平木，乃以五行顺相平者言也，此以五行更相平者言也。
“更”与“顺”，自当有别，不然，越人何不径云补金，使得平木，而乃曰“泻南方，补北方”哉。越人之
微意，正欲泻火以泄木之余，补水以实金之虚，五行递相济养，更互克伐，子为母复仇之义，故曰“欲令金
不得平木”也。此围魏救韩之意，不平之平，乃所以平也。陈氏训不字诚是，但于更字仍欠发明，故未免启
后人之疑，医道如伯仁，亦可谓精诣矣，乃以不字为衍文，余又不知其何见也。
第三十三难说：“肝色青，象征木；肺色白，象征金。肝遇水下沉，木遇水上浮；肺遇水上浮，金遇水下沉，这是什么道理呢？”回答者用五音、刚柔、吸受等概念来解释，这是为了启发后学者认识五行造化的奥妙。但注疏者又引用长生、临官、帝旺等说法，而不从肝肺本身的性质去深入探究其理，似乎解释得过于深奥，玄而又玄。万物皆具备五行属性，如果按照注疏的说法，心、脾、肾遇水也都下沉，那又该如何解释呢？依我愚见，不如平实讲解，自然明白通畅，且能启发后学者理解阴阳相感的意义，虽然文中没有明言，但道理其实蕴含其中。
肺虽然属金，但位置在膈肌之上，运行阳气较多，且其经脉为手太阴经，主司气。从形体而言，它是金；从功能而言，它是气。又因为属于手经，所以轻浮。肺煮熟后，手经之气消散，而金的形体独存，所以煮熟后就下沉了。肝虽然属木，但位置在膈肌之下，运行阴气较多，且其经脉为足厥阴经，主司血。从形体而言，它是木；从功能而言，它是血。又因为属于足经，所以下沉。肝煮熟后，足经之血消散，而木的形体独存，所以煮熟后就上浮了。这体现了返本归原的意义。至于临官、帝旺的说法，我觉得有些牵强附会，学习者请仔细斟酌。
生生子说：第七十五难说：“经文说东方实（肝木实），西方虚（肺金虚），泻南方（心火），补北方（肾水），这是什么意思呢……”所以通过泻火补水，想要让金不能直接平抑木。经文说：“不能治疗其虚弱，还问其他什么呢”，就是这个意思。”滑伯仁说：“‘不’字可能是衍文（多余的字）。四明陈氏说：张仲景说：木行乘金，称为‘横’。《内经》说：‘气有余，则克制自己所能胜的，并欺侮自己所不能胜的。’木实金虚，这是木气横逆而凌犯金，是欺侮自己所不能胜的。木实本来应该由金来平抑它，然而因为木气正强盛而横逆，金来平抑它就会导致两败俱伤地争斗，争斗则实证的一方也受伤，虚证的一方也败坏。金虚本来需要土气来资助，然而当时土也受到制约，不足以资助金。所以取水作为金的儿子，又作为木的母亲，于是泻火补水，使水胜过火，那么火就会因匮乏而从木那里索取气，木气因此减少而不能恢复充实，水是木的母亲，这就是‘母能令子虚’的道理。木既然不实，其气就平和了，平和则金免于被木凌犯，而不再虚弱，水是金的儿子，这就是‘子能令母实’的道理。所谓‘金不得平木’，意思是不能让金直接去平抑木，必须通过泻火补水来旁路治疗，使木和金的气自然平和罢了。而滑伯仁又说：陈氏的说法，自有其道理，只是被‘不’这一字纠缠困扰，显得牵强费辞，不如直接将‘不’字视为衍文。我说：‘不’字并非衍文，《难经》所说的‘不’，乃是姑息的意思，不让金直接去平抑木，所以才有泻火补水的治法，看越人（秦越人/扁鹊）说‘金木水火土，应当更相互相平抑’。‘更’字与‘不’字，乃是一篇的关键所在。这个‘更’字与第二十难中‘更相乘，更相伏’的‘更’字含义相同，谓互相平制，不是直接让金去平抑木。看张仲景说木行乘金称为‘横’的‘横’字，就知道金并非普通的虚弱，即使骤然进补，尚且不能自保，何况想让它能平抑木呢？那种金能够平抑木的情况，是从五行顺次相克的意义上说的，这里是从五行更相互相平抑的意义上说的。‘更’与‘顺’，自然应当有区别，否则，越人为什么不直接说补金，让它得以平抑木，而要说‘泻南方，补北方’呢？越人的微意，正是想通过泻火来泄除木的余气，通过补水来充实金的虚弱，五行递相济养，更互克伐，体现子为母复仇的意义，所以说‘想要让金不能（直接）平抑木’。这是围魏救韩的策略，不平之平，才是所谓的平。陈氏训释‘不’字确实正确，但在‘更’字上仍然缺乏阐明，所以难免引起后人的疑惑。医道如滑伯仁，也可以说是精到了极点，却认为‘不’字是衍文，我又不知道他是什么见解了。
The Thirty-Third Difficulty states: "The liver is green and symbolizes Wood; the lung is white and symbolizes Metal. The liver sinks in water, while Wood floats in water; the lung floats in water, while Metal sinks in water. What is the meaning of this?" The response uses concepts such as the Five Tones (Wuyin), Gang-Rou (Hardness and Softness), and Xi-Shou (Absorption and Reception) to explain this. This serves to inspire later learners to recognize the profound mysteries of the creation and transformation of the Five Elements (Wuxing). However, commentators have further invoked terms like Changsheng (Long Life), Linguan (Approaching Office), and Diwang (Imperial Prosperity), without thoroughly investigating the theory based on the specific nature of the Liver and Lung. This seems overly profound and abstruse. All things possess the attributes of the Five Elements; if we follow the commentators' explanation, the Heart, Spleen, and Kidney would also sink in water. How should this be interpreted? In my humble opinion, it is better to explain it plainly, which will naturally be clear and accessible, and can also help develop the learner's understanding of the principle of Yin-Yang mutual interaction. Although not explicitly stated, the rationale is implied therein.
Although the Lung belongs to Metal, its position is above the diaphragm, where Yang Qi circulates more abundantly. Its meridian is the Hand-Taiyin (Lung Meridian), which governs Qi. From the perspective of form/substance (Ti), it is Metal; from the perspective of function/application (Yong), it is Qi. Furthermore, because it belongs to the Hand meridians, it is light and floats. When the lung is cooked, the Qi of the Hand meridian dissipates, leaving only the substance of Metal, so it sinks after cooking.
Although the Liver belongs to Wood, its position is below the diaphragm, where Yin Qi circulates more abundantly. Its meridian is the Foot-Jueyin (Liver Meridian), which governs Blood. From the perspective of form/substance (Ti), it is Wood; from the perspective of function/application (Yong), it is Blood. Furthermore, because it belongs to the Foot meridians, it sinks. When the liver is cooked, the Blood of the Foot meridian dissipates, leaving only the substance of Wood, so it floats after cooking. This reflects the principle of returning to the root. The theories of Linguan and Diwang seem somewhat forced; students should examine this carefully.
Shengshengzi said: The Seventy-Fifth Difficulty states: "The classic says: 'The East is excess (Liver/Wood), the West is deficient (Lung/Metal); drain the South (Heart/Fire), tonify the North (Kidney/Water). What does this mean?'... Therefore, by draining Fire and tonifying Water, one intends to prevent Metal from directly leveling Wood. The classic says: 'If you cannot treat the deficiency, why ask about the rest?' This is what it means." Hua Borun (Hua Tuo's descendant/commentator) said: "The character 'Bu' (Not) is likely a superfluous character (yanwen)." Chen Shiming (Chen Wuze) said: Zhang Zhongjing stated that when Wood overacts on Metal, it is called 'Heng' (Horizontal/Rebellious). The *Neijing* states: 'When Qi is in excess, it controls what it normally overcomes and insults what it normally cannot overcome.' With Wood excess and Metal deficiency, Wood is rebellious and insults Metal, insulting what it cannot normally overcome. Normally, Metal should level Wood. However, since Wood's Qi is strong and rebellious, if Metal attempts to level it, they will struggle against each other. In this struggle, both the excess condition and the deficiency condition suffer. Metal deficiency originally relies on Earth for support, but at that time, Earth is also constrained and insufficient to support Metal. Therefore, Water is selected as the son of Metal and the mother of Wood. By draining Fire and tonifying Water, Water overcomes Fire. Consequently, Fire becomes weak and draws Qi from Wood, causing Wood to decrease and fail to restore its excess. Since Water is the mother of Wood, this follows the principle that 'the mother can make the child deficient.' Once Wood is no longer excessive, its Qi becomes balanced. Being balanced, Metal is spared from being insulted by Wood and ceases to be deficient. Since Water is the son of Metal, this follows the principle that 'the child can make the mother substantial.' The phrase 'Metal does not level Wood' means that Metal should not directly level Wood. Instead, one must treat indirectly by draining Fire and tonifying Water, allowing the Qi of Wood and Metal to naturally become balanced.
Hua Borun further stated: "Chen's interpretation has its own merit, but it is entangled by the single character 'Bu', appearing forced and verbose. It would be better to regard 'Bu' as a superfluous character." I say: "'Bu' is not a superfluous character. The 'Bu' in the *Nan Jing* implies a concept of forbearance or indirect action, meaning Metal does not directly level Wood, hence the treatment of draining Fire and tonifying Water. Consider Bian Que (Yue Ren) stating: 'Metal, Wood, Water, Fire, and Earth should mutually and alternately level each other.' The character 'Geng' (Alternate/Mutual) and the character 'Bu' (Not) are the key points of this chapter. This 'Geng' shares the same meaning as the 'Geng' in the Twentieth Difficulty ('mutually overcoming, mutually subduing'), indicating mutual regulation, rather than directly letting Metal level Wood. Observing Zhang Zhongjing's use of 'Heng' (Rebellious) for Wood overacting on Metal, we know that Metal's deficiency is not trivial. Even if rapidly tonified, it might not even sustain itself, let alone level Wood. The scenario where Metal levels Wood refers to the normal sequence of Five Elements control. Here, it refers to the mutual and alternate regulation of the Five Elements. 'Geng' (Alternate) and 'Shun' (Sequential) must be distinct. Otherwise, why did Bian Que not simply say 'Tonify Metal to allow it to level Wood,' but instead said 'Drain the South, Tonify the North'? Bian Que's subtle intent was precisely to drain Fire to vent the surplus of Wood, and tonify Water to fill the deficiency of Metal. The Five Elements nourish each other in turn, overcoming and subduing each other alternately, embodying the principle of the child avenging the mother. Hence, it says 'intending to let Metal not [directly] level Wood.' This is akin to the strategy of 'Besieging Wei to Rescue Han'; an apparent imbalance is used to achieve true balance. Chen's interpretation of 'Bu' is indeed correct, but he failed to elucidate 'Geng', thus inevitably arousing doubt among later learners. Hua Borun, whose medical knowledge was extremely refined, regarded 'Bu' as a superfluous character. I do not understand his reasoning."