（硝石，即火硝亦名焰硝；芒硝，硝之经煎炼而凝底成块者为朴硝，亦名皮硝，在上生
细芒
李濒湖谓∶朴硝下走，火硝上升。火硝得火则焰生，与樟脑火酒之性同。本经言其寒，
别录言其大寒；实乃大温。刘氏引伸其说，谓水硝治热之结。热结多属血分，所谓阴不降，
阳不化者也。能行阴中之阳结，则阴降阳自化矣。火硝治热之郁，热郁多属气分，所谓阳不
升，阴不畅者也。能达阳中之阴郁，则阳化阴自畅矣。邹氏又以火硝为性向阳，解自阴而阳
之盛热；水硝为性向阴，故逐伏在阳之实结。斯三家可谓发前人所未发矣。虽然，愚窃有未
安焉。阴阳之理，至为微妙，就物论物，易圆其说。以物合证与方而论之，则难于确当，难
于莹彻。浑言之而深，何如切言之而浅也。火硝固上升而散，固在气分，然其升散者为阴中
热郁之气，非阳中热郁之气。病在阴经、阴脏为阴，病有阴邪亦为阴。盖其辛温际上，咸苦
入下，凡在上在下之病胥治之，而总归于解阴中之热郁。刘氏达阳中阴郁一语，得毋犹有可
商。试核之证，来复丹、二气丹、玉真丸，皆阴邪中有伏热，金匮硝石矾石散尤彰彰者。惟
大黄硝石汤用以下夺，不与升散之旨相戾欤？乃其证为黄瘅腹满小便不利面赤，热为阳邪，
得湿而郁，且独在里，里实而表和，是亦阴中之邪也。阴中之邪，非咸苦何以得入。舍芒硝
用硝石者，以表虽汗出而表间之湿热自在。硝石辛温胜于咸苦，故于大黄柏栀下夺之中，加
兹一味以达表而散邪。夫火硝之不易明者，为其以温治热耳。若水硝以寒治热，曰走血，曰
润下，曰 坚，曰破结，固宜古今无异词，然亦何尝易明哉。大承气、调胃承气、桃核承气
，洵可谓去血中热结矣。独大陷胸汤丸用芒硝至一升半升，而其所治为结胸。纵云破结软坚
，非多不济，独不虑下降之物，用之多不愈速其降耶。是则有故矣。芒硝乃煎硝时结之于上
者，细芒如锋，质本轻于朴硝，味复兼辛，宁无上升之性，宁不入气分，后世且以治口舌咽
喉诸热证，谓芒硝不能际上治上可乎。由斯以观，刘氏阴中阳结之说，恐亦有未然者。仲圣
有言，病发于阳而反下之，热入因作结胸，据此自非阴中之阳结。又凡仲圣用芒硝之方，皆
阳证无伏阴。用硝石之方，则一证中有阴有阳。然则行阴中阳结者，乃硝石非芒硝。芒硝者
，逐阳证之热结者也。芒硝咸寒胜于苦辛，多煮则下益速，下速则遗上邪，故仲圣必后纳微
煮而少扬之。硝石辛温胜于咸苦，微煮则升之亟，升亟则不入下，故仲圣于二升中煮取一升
而少抑之。此似二物正相对待。刘氏于二物亦似以对待释之，而不知非也。咸与寒皆阴也，
其微辛不过挟有升性，并不能治阴邪。咸与温则阴阳异趣矣，温而兼辛，辛温而兼辛润，则
必阴中有阳邪之证，始克任之。其中奥旨，猝不易悟，故曰非对待也。抑刘氏以入血分为阴
中乎。血分为阴，则大承气当曰太阴病，不当曰阳明病。桃核承气当曰少阴病，不当曰太阳
病。芒硝盖血药而亦不专入血者，与大黄颇有似处。大黄味苦入心，能开胸膈之热结，若与
芒硝皆不宜于气病。胸膈之间，其能堪此重剂哉。邹氏以火硝向阳，水硝向阴，为脏病移腑
，腑病移躯体之所以然，此尤不可不辨者。本经积热曰五脏，岂悉能入胃使胀闭。病曰百病
，岂尽在于躯体。谓火硝性向阳，解自阴而阳之盛热。向阳自即入阳，何以先入于阴，宁得
谓非其所向。谓水硝性向阴，逐伏在阳之实结。所逐在阳，所向亦必在阳，反是则有异谋，
人固有之，物所必无。此等近似之谈，并无真理可求，徒眩人目耳。邹氏更有误者，谓己椒
苈黄丸加芒硝以治渴，是去其痼癖，正使津液流行。小柴胡汤加芒硝以止痢，是去其积聚，
正所以止下痢。噫，是亦不深思矣。己椒苈黄丸之证，原非固癖，大黄决不止用一两（有方
解详大黄），芒硝亦不后加。况方后云∶先食饮服一丸，日三服，稍增，口中有津液，渴者
加芒硝半两。是无芒硝，津液非不能生，岂加芒硝之津液与此有异耶。徐氏、尤氏皆云渴是
胃热，故加芒硝，邹氏坐泥本经太过耳。柴胡加芒硝汤云∶潮热者实也。热实无不下之理，
以柴胡加芒硝汤主之，即所以治热实。云∶纳芒硝更煮微沸，分温再服，不解更作。加芒硝
非欲其解而何！？邹氏之说，何与相反，殆误会今反利句耳。不知仲圣明云微利，明云下非
其治，下之而仍潮热，安得不以对证之下药继之，此读古书所以贵细心寻绎也。
硝石，就是火硝，也叫焰硝；芒硝，是硝经过煎煮提炼后凝结成块的，称为朴硝，也叫皮硝。李时珍说：朴硝药性下行，火硝药性上行。火硝遇到火就会燃烧产生火焰，其性质与樟脑、火酒相同。《神农本草经》说它性寒，《名医别录》说它大寒；但实际上它是大温之性。刘氏引申这个说法，认为水硝（芒硝）治疗热邪的结聚。热结多属于血分，所谓阴气不能下降，阳气不能化生。能够疏通阴中的阳结，那么阴气下降，阳气自然就能化生。火硝治疗热邪的郁滞，热郁多属于气分，所谓阳气不能上升，阴气不能通畅。能够通达阳中的阴郁，那么阳气化生，阴气自然就能通畅。邹氏又将火硝解释为性质趋向于阳，能解除从阴转阳的盛热；水硝性质趋向于阴，所以驱逐潜伏在阳分的实邪结聚。这三家的观点可以说是阐发了前人未曾发现的问题。虽然如此，我私下里觉得有些不安。阴阳的道理非常微妙，就事物本身论事物，容易把话说圆。但如果将药物结合病症和方剂来讨论，就很难确切恰当，很难透彻明白。笼统地说显得深奥，何如具体地说得浅显易懂呢？火硝确实具有升散的特性，确实作用于气分，但它所升散的是阴中的热郁之气，而不是阳中的热郁之气。病在阴经、阴脏属于阴，病有阴邪也属于阴。大概是因为它辛温能达上焦，咸苦能入下焦，凡是上部或下部的病都能治疗，但总归归结为解除阴中的热郁。刘氏所说的“通达阳中阴郁”这句话，恐怕还有值得商榷的地方。试核对临床证候，来复丹、二气丹、玉真丸，都是阴邪中有伏热，金匮要略中的硝石矾石散更是明显的例子。只有大黄硝石汤用以下夺攻下，这难道不与升散的宗旨相违背吗？然而它的证候是黄疸、腹部胀满、小便不利、面色红赤，热邪属于阳邪，遇湿而郁滞，且独存于体内，里实而表证已解，这也是阴中之邪。阴中之邪，不用咸苦之味怎么能进入？舍弃芒硝而用硝石的，是因为虽然表证有汗出，但体表的湿热依然存在。硝石辛温胜于咸苦，所以在用大黄、黄柏、栀子攻下的方剂中，加入这一味药以通达体表而疏散邪气。火硝难以理解的地方，在于它以温性治疗热证。至于水硝以寒性治疗热证，说它走血分、润下、软坚、破结，古今都没有异议，但这其中道理又何尝容易明白呢？大承气汤、调胃承气汤、桃核承气汤，确实可以说是去除血中的热结了。唯独大陷胸汤丸使用芒硝多达一升到半升，而它所治疗的却是结胸证。纵然说是破结软坚，不多用不行，难道不担心下降的药物，用得越多不是加速其下降吗？这是有原因的。芒硝是在煎煮硝时凝结在上层的，细芒如锋，质地本来比朴硝轻，味道又兼有辛味，难道没有上升的性质吗？难道不入气分吗？后世甚至用它治疗口舌咽喉的各种热证，如果说芒硝不能达上治上，可以吗？由此看来，刘氏关于“阴中阳结”的说法，恐怕也有不妥之处。仲景有言：“病发于阳而反下之，热入因作结胸”，据此来看，这显然不是阴中的阳结。而且凡仲景用芒硝的方子，都是阳证而没有伏阴。用硝石的方子，则一个证候中既有阴又有阳。那么，行阴中阳结的，是硝石而不是芒硝。芒硝，是驱逐阳证热结的药物。芒硝咸寒胜于苦辛，多煮则下行速度越快，下行快则遗留上部邪气，所以仲景必定在后放入微煮并少搅拌。硝石辛温胜于咸苦，微煮则上升迅速，上升迅速则不入下部，所以仲景在二升水中煮取一升时稍微抑制它。这看似两物正好相对待。刘氏对两物似乎也以对对待释，却不知道并非如此。咸与寒都属于阴，其微辛不过带有升性，并不能治疗阴邪。咸与温则阴阳趋向不同，温而兼辛，辛温而兼辛润，则必须是阴中有阳邪的证候，才能胜任。其中的奥妙，仓促间不容易领悟，所以说不是简单的对待关系。再说刘氏认为入血分为阴中吗？如果血分为阴，那么大承气汤应当说是太阴病，不应当说是阳明病。桃核承气汤应当说是少阴病，不应当说是太阳病。芒硝大概是血分药但也并不专入血分，与大黄颇有相似之处。大黄味苦入心，能开胸膈的热结，如果与芒硝都用于气病，胸膈之间，哪里能承受得住这样重剂的药力呢？邹氏认为火硝向阳，水硝向阴，这是脏病传腑、腑病传躯体身体的原因，这一点尤其不可不辨明。《本经》说的积热在五脏，难道都能入胃导致胀闭吗？病说百病，难道都在躯体身体吗？如果说火硝性质向阳，解除从阴转阳的盛热。向阳自然就是入阳，为什么先入于阴，难道能说这不是它的所向吗？如果说水硝性质向阴，驱逐潜伏在阳分的实结。所逐在阳，所向也必在阳，反过来就是有异谋，人或许有这种心思，物体必然没有。这种似是而非的谈论，并没有真理可求，只是眩惑人的眼睛罢了。邹氏更有错误之处，他说己椒苈黄丸加芒硝以治疗口渴，是去除痼癖，正使津液流行。小柴胡汤加芒硝以止痢，是去除积聚，正是为了停止下痢。唉，这也是不深思的结果。己椒苈黄丸的证候，原本就不是固定的癖块，大黄决不会只用一两（方解详见大黄条），芒硝也不会后加。况且方后注说：“先吃饭服药丸，每天三次，稍增加剂量，口中出现津液，口渴者加芒硝半两。”如果没有芒硝，津液也不是不能生成，难道加了芒硝的津液与此有什么不同吗？徐氏、尤氏都说口渴是胃热，所以加芒硝，邹氏是拘泥于《本经》太过罢了。柴胡加芒硝汤说：“潮热者是实证。”热实没有不攻下的道理，用柴胡加芒硝汤主治，就是用来治疗热实的。又说：“纳芒硝再煮微沸，分两次温服，不解再作。”加芒硝难道不是为了攻下吗！？邹氏的说法，为何与此相反，大概是误解了“今反利”这句话吧。不知道仲景明确说“微利”，明确说“下非其治”，下之后仍然潮热，怎么不对证下药继之呢？这就是读古书之所以贵在细心寻绎的原因。
Nuxitong (Sal Nitri, Stone Nitre), also known as Huoxiao (Fire Nitre) or Yanniao (Flame Nitre); Mangxiao (Mirabilite), which is the substance formed when Xiao (Nitre) is boiled and condensed into blocks, is called Puxiao (Raw Nitre) or Pixiao (Skin Nitre). Li Shizhen stated: Puxiao acts downward, while Huoxiao acts upward. Huoxiao produces flames when exposed to fire; its nature is similar to that of Borneolum Syntheticum (Zhangnao) and distilled spirits (Huojio). The *Shennong Bencao Jing* states it is cold, while the *Mingyi Bielu* states it is extremely cold; however, in reality, it is extremely warm. Liu extended this theory, claiming that Shuixiao (Water Nitre, i.e., Mangxiao) treats heat accumulation. Heat accumulation mostly belongs to the Blood level, described as "Yin fails to descend, Yang fails to transform." It can move the Yang accumulation within Yin, causing Yin to descend and Yang to transform naturally. Huoxiao treats heat stagnation, which mostly belongs to the Qi level, described as "Yang fails to ascend, Yin fails to flow smoothly." It can penetrate the Yin stagnation within Yang, causing Yang to transform and Yin to flow smoothly. Zou further interpreted Huoxiao as having a nature tending toward Yang, capable of resolving intense heat arising from Yin transforming into Yang; whereas Shuixiao has a nature tending toward Yin, thus expelling solid accumulations hidden within Yang. These three scholars can be said to have uncovered insights previously unmentioned by predecessors. Nevertheless, I privately feel uneasy about this. The principles of Yin and Yang are subtle; discussing substances in isolation makes it easy to rationalize arguments. However, integrating substances with clinical manifestations and formulas makes it difficult to be precise and thorough. Speaking generally may seem profound, but is it not better to speak specifically and plainly? Huoxiao indeed ascends and disperses, acting on the Qi level, but what it ascends and disperses is the Qi of heat stagnation within Yin, not heat stagnation within Yang. Diseases in Yin meridians or Yin organs are Yin; diseases caused by Yin pathogens are also Yin. Generally, because its acrid-warm nature reaches the upper body and its salty-bitter nature enters the lower body, it treats diseases both above and below, ultimately归结ing to resolving heat stagnation within Yin. Liu's phrase "penetrating Yin stagnation within Yang" is perhaps still debatable. Examining clinical cases, Laifu Dan, Erqi Dan, and Yuzhen Wan all treat latent heat within Yin pathogens; Xiaoni Shi Fanshi San in the *Jingui Yaolue* is particularly evident. Only Dahuang Xiaoshi Tang uses purgation to drain downward, which seems contrary to the principle of ascending and dispersing. However, its symptoms include jaundice, abdominal fullness, difficulty urinating, and red face. Heat is a Yang pathogen; it stagnates due to dampness and resides solely in the interior. With interior excess and resolved exterior, this is also a pathogen of Yin. How else can one enter such Yin pathogens without salty and bitter flavors? Discarding Mangxiao for Xiaoshi is because although there is sweating at the exterior, damp-heat remains between the tissues. Xiaoshi is more acrid-warm than salty-bitter; therefore, among the purgative agents like Dahuang, Huangbai, and Zhizi, adding this ingredient helps reach the exterior and disperse pathogens. The difficulty in understanding Huoxiao lies in its use of warmth to treat heat. Regarding Shuixiao using coldness to treat heat, stating it enters the blood, moistens downward, softens hardness, and breaks accumulations has been consistent since ancient times. Yet, is it truly easy to understand? Dachengqi Tang, Tiaowei Chengqi Tang, and Taohe Chengqi Tang certainly remove heat accumulations in the blood. However, only Daxiexiong Tang/Wan uses a large amount of Mangxiao (one to half a sheng) to treat Jie Xiong (Chest Binding). Even if one claims it breaks accumulations and softens hardness, requiring large doses, does one not worry that heavy descending agents might accelerate their descent too quickly? There is a reason. Mangxiao is the substance condensed at the top during the boiling process of Nitre. Its fine crystals are sharp, its texture is lighter than Puxiao, and its taste includes acridity. Does it not possess an ascending nature? Does it not enter the Qi level? Later generations even used it to treat heat syndromes of the mouth, tongue, throat, and pharynx. Can we say Mangxiao cannot reach the upper body to treat upper disorders? From this perspective, Liu's theory of "Yang accumulation within Yin" seems questionable. Zhongjing said, "When a disease originates in Yang and is incorrectly treated with purgation, heat enters and causes Chest Binding." Based on this, it is clearly not Yang accumulation within Yin. Furthermore, all formulas by Zhongjing using Mangxiao treat Yang syndromes without latent Yin. Formulas using Xiaoshi involve both Yin and Yang within a single syndrome. Thus, moving Yang accumulation within Yin is done by Xiaoshi, not Mangxiao. Mangxiao expels heat accumulations in Yang syndromes. Mangxiao is salty and cold, surpassing bitter and acrid; prolonged boiling accelerates its descent. Rapid descent leaves pathogens in the upper body; hence, Zhongjing always adds it later, boils briefly, and stirs gently. Xiaoshi is acrid and warm, surpassing salty and bitter; brief boiling accelerates its ascent. Rapid ascent prevents it from entering the lower body; hence, Zhongjing boils two shengs down to one sheng to slightly restrain it. These two substances seem to oppose each other. Liu also seemed to interpret them as opposites, but he was mistaken. Salty and cold are both Yin; its slight acridity merely carries an ascending property and cannot treat Yin pathogens. Salty and warm represent different Yin-Yang orientations. Warmth combined with acridity, and acrid-warmness combined with moistening, applies only to syndromes where Yang pathogens exist within Yin. The profound meaning here is not easily grasped suddenly; thus, it is not a simple opposition. Moreover, does Liu consider entering the blood level as being within Yin? If the blood level is Yin, then Dachengqi Tang should be termed Taiyin Disease, not Yangming Disease. Taohe Chengqi Tang should be Shaoyin Disease, not Taiyang Disease. Mangxiao is likely a blood-invigorating agent but does not exclusively enter the blood; it resembles Dahuang significantly. Dahuang is bitter, enters the Heart, and opens heat accumulations in the chest and diaphragm. If both were used for Qi disorders, could the chest and diaphragm withstand such heavy medications? Zou claimed that Huoxiao tending toward Yang and Shuixiao tending toward Yin explains why Zang diseases transfer to Fu organs and Fu diseases transfer to the limbs/body. This requires clarification. The *Bencao Jing* mentions accumulated heat in the Five Zang organs; do they all enter the Stomach to cause distension and closure? Diseases are myriad; are they all located in the limbs/body? If Huoxiao tends toward Yang to resolve intense heat from Yin to Yang, tending toward Yang means entering Yang. Why enter Yin first? How can this not be its direction? If Shuixiao tends toward Yin to expel solid accumulations in Yang, what is expelled is in Yang, so its direction must also be Yang. To act otherwise implies ulterior motives. Humans may have such thoughts, but objects certainly do not. Such approximate discussions seek no truth and merely dazzle the eyes. Zou made another error, stating that adding Mangxiao to Jijiang Lihuang Wan to treat thirst removes stubborn masses, thereby promoting fluid circulation. Adding Mangxiao to Chaihu Jia Mangxiao Tang to stop dysentery removes accumulations, thereby stopping diarrhea. Alas, this shows a lack of deep thought. The syndrome of Jijiang Lihuang Wan is originally not a fixed mass; Dahuang would never be used in such small amounts (see Dahuang commentary); Mangxiao would not be added later. Moreover, the post-prescription note says: "Take one pill before meals, three times a day, gradually increase. If saliva appears in the mouth, add half liang of Mangxiao if thirsty." Without Mangxiao, fluids can still be generated. Is the fluid generation with Mangxiao different from that without it? Xu and You stated that thirst indicates Stomach heat, hence Mangxiao is added. Zou was too rigidly attached to the *Bencao Jing*. Chaihu Jia Mangxiao Tang states: "Tidal fever indicates excess." Heat-excess syndromes require purgation. Using Chaihu Jia Mangxiao Tang treats this heat-excess. It also says: "Add Mangxiao, boil until barely simmering, divide into two warm doses. If unresolved, prepare again." Was Mangxiao added not for purgation!? Why does Zou's view contradict this? He likely misunderstood the phrase "now there is loose stool." Zhongjing explicitly stated "slight loose stool" and "purgation is not the correct treatment." If tidal fever persists after purgation, how can one not follow up with appropriate purgatives? This is why careful examination is essential when reading ancient texts.