鳖甲牡蛎之用，其显然有异者，自不致混于所施。惟其清热 坚，人每视为一例，漫无
区分。不知此正当明辨而不容忽者。甲介属金，金主攻利，气味咸寒则入阴，此二物之所同，
清热 坚之所以并擅；而其理各具，其用亦因而分。鳖有雌无雄，其甲四围有肉裙，以肉裹
甲，是为柔中有刚，阴中有阳。蛎有雄无雌， 相连如房，房内有肉，是为刚中有柔，阳
中有阴。鳖介属而卵生色青，则入肝而气沉向里。蛎介属而化生色白，且南生东向，得春木
之气，则入肝而气浮向外。向里则下连肾，向外则上连胆。本经于鳖甲主心腹症瘕坚积，于
牡蛎主惊恚怒气拘缓。仲圣用鳖甲于鳖甲煎丸，所以破症瘕。加牡蛎于小柴胡汤，所以除胁
满。所谓向里连肾向外连胆者，正即此可推其 坚不能无 钝之差，清热亦大有深浅之别也。
由斯以观，凡鳖甲之主阴蚀、痔核、骨蒸者，岂能代以牡蛎。牡蛎之主盗汗、消渴、瘰 颈
核者，岂能代以鳖甲。鳖甲去恶肉而亦敛溃痈者，以阴既益而阳遂和也。牡蛎治惊恚而又止
遗泄者，以阳既戢而阴即固也。
考仲圣文蛤散、文蛤汤，渴不用栝蒌之属，有表邪不用桂枝之属，而独用文蛤，几莫明
其故。迨即所治之三证细究之，而后知宜文蛤不宜他药者，固自有至精至切之义焉。蛤者雀
所化，具自外飞入水之概。壳有文彩，又其精气所注。用在壳而味咸，则为由表以入里；气
寒性燥，则能清热而胜湿。其清里热，只清上焦心肺之热；以咸平无深入之能，气复走表，
又分其势也。活人书治血结胸，李防御治痰嗽面肿，皆治在心肺之明征。而仲圣又有精者焉。
病在阳，应汗解而不汗解，则热邪遗留于表。以冷水 之灌之，内心烦而外粟起，则其寒为
外附之寒，不必治寒而只须治热治湿，文蛤治表间热湿，恰与证合。若不瘥，必热已退而咸
寒不克任之。与五苓散者，取其淡辛化气而表邪得尽也。吐后渴欲得水而贪饮，贪饮由心肺
热炽，渴饮在于吐后，必表间尚有余邪。故以麻杏发汗，即以文蛤协石膏清热，甘草和之于
中，姜枣调之于表，麻杏只三两而蛤膏各用至五两，意自在于清热。麻杏力微，故兼主微风，
此汤实非为风寒设也。至渴欲饮水不止，亦主以文蛤散。不止即贪饮之谓，而无吐后之余邪
，则止其热渴，已足疗病。文蛤治表热不必有渴，治心肺之里热，则正能止渴。盖其渴非津
亏与小便不利也。
鳖甲与牡蛎的应用，其明显不同的地方，自然不会混淆在施用中。只是它们清热、软坚（软化坚硬结块）的功效，人们常视为一类，漫无区分。不知道这正是应当明辨而不容忽略的。介壳类属金，金主攻利，气味咸寒则入阴分，这是这两味药的共同点，也是它们能并擅清热、软坚的原因；但它们的原理各具特色，应用也因此分开。鳖有雌无雄，它的甲四周围有肉裙，以肉包裹甲，这是柔中有刚，阴中有阳。牡蛎有雄无雌，壳相连如房，房内有肉，这是刚中有柔，阳中有阴。鳖属于介壳类且卵生，颜色青，则入肝经且气沉向里。牡蛎属于介壳类且化生，颜色白，且南方生长、向东朝向，得春木之气，则入肝经且气浮向外。向里则下连肾，向外则上连胆。《神农本草经》对于鳖甲主治心腹症瘕（腹内结块）、坚积，对于牡蛎主治惊恚怒气拘缓。张仲景在鳖甲煎丸中使用鳖甲，是为了破除症瘕。在小柴胡汤中加入牡蛎，是为了消除胁满。所谓向里连肾、向外连胆，正可以从这里推知其软坚之力不能没有钝利的差别，清热也大有深浅的区别。由此看来，凡是鳖甲主治阴蚀、痔核、骨蒸劳热（阴虚发热）的，怎么能用牡蛎代替。牡蛎主治盗汗、消渴、瘰疬颈核（颈部淋巴结结核）的，怎么能用鳖甲代替。鳖甲去除恶肉也能收敛溃烂痈疽，是因为阴既补益而阳遂调和。牡蛎治疗惊恚又能止遗泄，是因为阳既收敛而阴即固摄。
考察张仲景的文蛤散、文蛤汤，口渴不用栝蒌之类，有表邪不用桂枝之类，而独用文蛤，几乎没有人明白其中的缘故。等到就所治疗的三种证候仔细考究之后，才知道适宜用文蛤而不宜用其他药物，固然自有至精至切的道理。蛤是雀鸟变化而来，具备从外飞入水中的态势。壳有文采，又是其精气所注。用在壳上且味道咸，则是从表进入里；气寒性燥，则能清热而胜湿。它清里的热，只清上焦心肺的热；因为咸平没有深入的能力，气又走表，又分散了它的势。《活人书》治疗血结胸，李防御治疗痰嗽面肿，都是治疗在心肺的明确证据。而张仲景又有精妙的地方。病在阳分，应当发汗解表而不发汗解表，则热邪遗留于表。用冷水喷洒浇灌它，内心烦闷而体表起粟粒状皮疹，则这种寒是外附之寒，不必治寒而只需治热治湿，文蛤治疗表间的热湿，恰好与证候相合。如果不好，一定是热已退而咸寒之药不能胜任。给予五苓散，取其淡辛化气而使表邪得以尽除。呕吐后口渴想喝水且贪饮，贪饮是由于心肺热炽盛，口渴发生在呕吐之后，一定表间尚有余邪。所以用麻黄杏仁发汗，同时用文蛤协助石膏清热，甘草在中焦调和，生姜大枣在表调护，麻黄杏仁只用三两而蛤膏各用至五两，意图自然在于清热。麻黄杏仁力量微弱，所以兼主微风，这个汤实际上不是为风寒设立的。至于口渴想喝水不止，也主要用文蛤散。不止就是贪饮的意思，而没有呕吐后的余邪，那么止住热渴，已经足以疗病。文蛤治疗表热不一定有口渴，治疗心肺的里热，则正好能止渴。大概这种口渴不是津液亏损和小便不利引起的。
The applications of *Bie Jia* (Tartar Testudinis Carapax) and *Mu Li* (Ostreae Concha) have obvious differences, so they are not likely to be confused in their use. However, people often regard their effects of clearing heat and hardening (softening hardness) as one category, without distinction. It is unknown that this is precisely what should be clearly distinguished and cannot be ignored. Shellfish belong to Metal; Metal governs attacking and promoting flow. Their flavor is salty and cold, entering the Yin aspect. This is common to both substances, which is why they both excel at clearing heat and softening hardness; yet their principles differ, and thus their uses diverge. The turtle has females but no males; its shell is surrounded by a fleshy skirt, with flesh wrapping the shell, representing softness within hardness, and Yin within Yang. The oyster has males but no females; the shells connect like rooms, with flesh inside the rooms, representing hardness within softness, and Yang within Yin. The turtle belongs to shellfish, lays eggs, and is green in color, thus entering the Liver channel with Qi sinking inward. The oyster belongs to shellfish, is generated through transformation, is white in color, grows in the south facing east, and obtains the Qi of Spring Wood, thus entering the Liver channel with Qi floating outward. Inward it connects downward to the Kidney; outward it connects upward to the Gallbladder. The *Shennong Bencao Jing* states that *Bie Jia* treats heart and abdominal zheng jia (masses) and firm accumulations, while *Mu Li* treats fright, resentment, anger, stiffness, and flaccidity. Zhang Zhongjing uses *Bie Jia* in *Bie Jia Jian Wan* (Turtle Shell Decoction for Masses) to break up masses. He adds *Mu Li* to *Xiao Chai Hu Tang* (Minor Bupleurum Decoction) to remove hypochondriac fullness. The statement "inward connecting to the Kidney, outward connecting to the Gallbladder" allows us to infer that there must be differences in the dullness or sharpness of their ability to soften hardness, and significant differences in the depth of their heat-clearing effects. From this perspective, whenever *Bie Jia* is indicated for yin erosion, hemorrhoidal nodules, or bone-steaming fever (deficiency heat), how can it be replaced by *Mu Li*? Whenever *Mu Li* is indicated for night sweats, Xiao Ke (wasting-thirst), or scrofula and cervical nodules, how can it be replaced by *Bie Jia*? *Bie Jia* removes foul flesh and also consolidates ulcerating carbuncles because, once Yin is nourished, Yang becomes harmonious. *Mu Li* treats fright and resentment and also stops leakage because, once Yang is restrained, Yin becomes secure.
Examining Zhang Zhongjing's *Wen Ge San* (Clam Powder) and *Wen Ge Tang* (Clam Decoction), when thirst does not use Trichosanthis Radix (*Gua Lou*) type herbs, and when exterior pathogenic factors do not use Cinnamon Twig (*Gui Zhi*) type herbs, but exclusively uses *Wen Ge* (Venerable Clam), few understand the reason. Only upon carefully investigating the three conditions treated can one know that the suitability of *Wen Ge* over other herbs inherently possesses profound and precise meaning. The clam is transformed from sparrows, possessing the characteristic of flying from outside into water. Its shell has patterns, which are the concentration of its essence and Qi. Used as the shell and tasting salty, it moves from the exterior to the interior; its Qi is cold and nature dry, thus able to clear heat and overcome dampness. Its clearing of interior heat only clears the heat of the Upper Jiao Heart and Lung; because salty and flat lacks the ability to penetrate deeply, and its Qi travels to the exterior, dispersing its force. The *Huoren Shu* (Book of Vitality) treating blood-stasis chest binding, and Li Fangyu treating phlegm-cough and facial swelling, are clear evidence of treatment focusing on the Heart and Lung. Zhang Zhongjing has another subtle point. When a disease is in the Yang aspect, sweating should resolve it, but if not resolved by sweating, heat pathogens remain in the exterior. Spraying and pouring cold water on it causes internal vexation and external pruritus (goosebumps); this cold is externally attached cold, requiring no treatment for cold, but only for heat and dampness. *Wen Ge* treating exterior heat and dampness fits the condition perfectly. If not cured, it must be that the heat has receded and salty-cold herbs are insufficient. Administering *Wu Ling San* (Five-Ingredient Powder with Poria) utilizes its bland and acrid properties to transform Qi and exhaust the exterior pathogen. After vomiting, thirst desires water and drinking greedily; greediness stems from blazing Heat in the Heart and Lung. Thirst occurring after vomiting implies residual pathogenic factors in the exterior. Thus, using Ephedra (*Ma Huang*) and Apricot Seed (*Xing Ren*) to induce sweating, while simultaneously using *Wen Ge* to assist Gypsum (*Shi Gao*) in clearing heat, Licorice (*Gan Cao*) to harmonize in the middle, and Ginger (*Sheng Jiang*) and Jujube (*Da Zao*) to regulate the exterior, where Ephedra and Apricot Seed are used in small amounts (3 liang) while Clam Paste is used in large amounts (5 liang each), the intent lies naturally in clearing heat. Since Ephedra and Apricot Seed have weak power, they also address slight wind; this decoction is actually not designed for Wind-Cold. As for thirst desiring water incessantly, *Wen Ge San* is primarily indicated. Incessant desire means greedy drinking, without residual exterior pathogen post-vomiting; thus stopping heat-thirst is sufficient to treat the illness. *Wen Ge* treating exterior heat does not necessarily require thirst; treating interior heat of the Heart and Lung precisely stops thirst. Generally, this thirst is not caused by fluid deficiency or difficulty in urination.