一名炉底。是银铅脚。岭南闽中银铜冶处有之。其初采矿时。银铜相杂。先以铅同
煎炼。银随铅出。又采山木叶烧灰。开地作炉。填灰其中。置银铅于灰上。更加火 。铅渗
灰下。银住灰上。罢火候冷。出银。其灰池感铅银气。置之。积久成密陀僧。（颂） 取于
银冶者。亦甚难得。今人多取销银铺炉底用之。（濒湖） 按银铺有分金炉。市匠将银油及
倾银坏罐。共捶成末。搅铅子拌匀。置分金炉上。火 出铅后。用大锅一口。入灰满锅。将
所烧出铅置锅内灰上。用炭火 化。则银在灰上。铅坠灰底。即陀僧。与银冶之灰池 法。
得银上而铅下者无异。
味咸辛甘。气平。有小毒。治久痢五痔。（牡酒肠血气五种）疗惊痫。并咳嗽。呕逆吐
痰。反胃。消渴。疟疾。下痢。止血。杀虫。消肿毒。治诸疮。去面上瘢 。并膏药用之。
感铅银之气。其性重坠下沉。直走下焦。（濒湖）惊气入心络。喑不能言。用密陀僧末一匕。
茶调服即愈。昔有人伐薪。为野狼所逐。而得是疾。或授此方而愈。又一军校采藤。逢恶蛇。
病此。亦用之而愈。盖惊则气乱。陀僧之重以去怯而平肝也。（夷坚志） 其功力与铅丹同。
故膏药中用以代之。痰结胸中不散。密陀僧一两。醋水各一盏。煎干为末。每服二钱。以酒
水各一小盏。煎一盏。温服。少顷当吐出痰涎为妙。肠风痔 。铜青密陀僧各一钱。麝香少
许。为末。津和涂之。骨疽出骨。（一名多骨疮不时出细骨）乃母受胎未及一月。与父交合。
感其精气而然。以密陀僧末。桐油调匀摊贴之。即愈。血风 疮。密陀僧用香油磨化。油纸
摊膏。反复贴之。
〔论〕 濒湖谓密陀僧重坠。直走下焦。能效坠痰止吐消积等证之用。殊不知铅本至阴。
其下行者乃返其所自始也。阴之不得下行而返其所始者。由于阴不足也。如久痢是伤其阴气
也。如惊痫是阴不足不能为阳之守。以病于惊。不能达阳之用。以病于痫也。又如反胃亦是
阴不足而不能下归。以致阳上逆也。陀僧所治诸证。大都不越于斯义。
密陀僧惟治 。（面黑气也）敷面外。今人无复用以服食者。大都可外敷。不可内服。
此药难得真者。销银炉底乃硝铜之气所结。能烂一切物。故益不宜轻用。（仲淳）
〔修治〕 炉底坚重。碎之如金色者佳。外敷生用。内服火 黄色。细研。
密陀僧，又名炉底。它是冶炼银铅后的残渣。在岭南和闽中等地银铜矿冶之处出产。起初开采矿石时，银和铜混杂在一起，先用铅一同煎炼，银便随着铅一起析出。又采集山木的叶子烧成灰，开辟地面做成炉子，将灰填入其中，把含有银铅的物质放在灰上面，再加火加热，铅渗入灰的下面，银则留在灰的上面。停止加热后等待冷却，取出银。这种灰池因为感应了铅和银的气息，放置久了就形成了密陀僧。（苏颂）从银矿冶炼中取得的密陀僧，也非常难得。现在的人多是从销银铺的炉底获取来使用。（李时珍）
据考证，银铺中有分金炉。市井工匠将银油以及倾倒银子的坏罐子，共同捶打成粉末，加入铅子拌匀，放置在分金炉上。用火煅烧使铅挥发出来后，用一口大锅，装入满锅的灰，将刚才烧出的铅放在锅内灰的上面，用炭火熔化，那么银就在灰的上面，铅沉坠到灰的底端，这就是陀僧。这与银矿冶炼中灰池的方法，得到银在上而铅在下的情况没有区别。
味道咸、辛、甘。性质平和。有小毒。治疗久痢、五痔（牡、酒、肠、血、气五种痔疮）。治疗惊痫，以及咳嗽、呕逆、吐痰、反胃、消渴、疟疾、下痢。具有止血、杀虫、消肿毒的功效。治疗各种疮疡，去除面部的瘢痕，也可作为膏药的辅料使用。
密陀僧感应了铅和银的气息，其性沉重下沉，直走下焦。（李时珍）惊气侵入心络，导致失音不能说话，用密陀僧末一匕，用茶调服即可痊愈。过去有人砍柴，被野狼追逐而得了这种病，有人传授此方而痊愈。又有一名军校采集藤条，遇到恶蛇，患了此病，也用此方而痊愈。大概是因为惊恐导致气机紊乱，密陀僧的沉重之性可以去除怯懦并平抑肝气。（《夷坚志》）
它的功力与铅丹相同，所以在膏药中用来替代它。如果痰结聚在胸中不散，用密陀僧一两，醋和水各一盏，煎至干燥后研为细末，每次服用二钱，用酒和水各一小盏，煎至一盏量，温服，过一会儿如果能吐出痰涎就很好。如果是肠风痔漏，用铜青和密陀僧各一钱，少许麝香，研为细末，用唾液调和涂抹患处。对于骨疽（一名多骨疮，不时排出细小骨头），这是母亲怀孕未满一个月时与父亲交合，感受精气所致，用密陀僧末，桐油调匀摊贴患处，即可痊愈。对于血风疮，用密陀僧香油磨化，涂在油纸上制成膏药，反复贴敷。
〔论述〕 李时珍认为密陀僧沉重下沉，直走下焦，能发挥坠痰、止吐、消积等作用。却不知道铅本性属至阴，其下行是返回它原本的状态。阴气不能下行而返回本源，是由于阴不足。比如久痢是损伤了阴气；比如惊痫是阴不足不能固守阳气，因受惊致病，不能发挥阳的作用，因而患痫病。又如反胃也是阴不足而不能下行归位，导致阳气上逆。密陀僧所治疗的诸种病症，大多都不超出这个义理。
密陀僧只用于治疗面黑气（面色晦暗无光）。除了外敷之外，现在的人不再用于内服。大体上都可以外敷，不可内服。这种药很难得到真品。销银炉底的产物乃是硝铜之气凝结而成，能腐蚀一切物体，因此更不宜轻易使用。（陈实功）
〔修治〕 炉底坚硬沉重，敲碎后呈现金色者为佳。外敷生用，内服需火煅至黄色，细细研磨。
Mirabilite (Mituoseng), also known as Furnace Bottom. It is the residue from smelting silver and lead. It is found in places where silver and copper are smelted, such as Lingnan and Minzhong. Initially, when mining ores, silver and copper are mixed together; lead is first added for simultaneous smelting, and the silver comes out along with the lead. Then, leaves of mountain trees are collected and burned into ash. A pit is dug to form a furnace, filled with ash. The material containing silver and lead is placed on top of the ash, and fire is applied. The lead seeps down into the lower part of the ash, while the silver remains on the upper part. After stopping the heat and waiting for cooling, the silver is extracted. This ash pit, having absorbed the qi of lead and silver, over time forms Mirabilite (Mituoseng). (Su Song) Mirabilite obtained from silver smelting is very rare. Nowadays, people mostly obtain it from the bottom of furnaces in silver-refining shops for use. (Li Shizhen)
According to research, silver-refining shops have gold-separating furnaces. Craftsmen beat silver oil and broken crucibles used for pouring silver into powder, mix them with lead particles, and place them on the gold-separating furnace. After heating to volatilize the lead, a large pot is filled with ash. The previously extracted lead is placed on top of the ash in the pot and melted with charcoal fire. The silver stays on the ash, while the lead sinks to the bottom of the ash. This is called Tuoseng. This method is identical to that of the ash pit in silver smelting, where silver ends up above and lead below.
Taste: Salty, Pungent, Sweet. Nature: Neutral. Slight toxicity. Treats chronic dysentery and five types of hemorrhoids (Mu, Jiu, Chang, Xue, Qi hemorrhoids). Treats fright epilepsy, as well as cough, vomiting, expectoration, retroflexion of the stomach (Fanwei), diabetes mellitus (Xiaoke), malaria, and dysentery. It stops bleeding, kills parasites, reduces swelling and detoxifies. Treats various sores, removes facial scars, and is used as an auxiliary ingredient in plasters.
Mirabilite (Mituoseng) absorbs the qi of lead and silver; its nature is heavy and sinking, acting directly on the Lower Jiao (Lower Burner). (Li Shizhen) When fright qi enters the collaterals of the Heart, causing aphonia (inability to speak), one spoonful of Mirabilite (Mituoseng) powder, taken with tea, can cure it. In the past, someone chopping wood was chased by a wild wolf and contracted this illness; using this prescription cured him. Another military officer collecting vines encountered a venomous snake and suffered from this condition; he was also cured by it. This is because fright causes chaotic qi movement; the heaviness of Tuoseng dispels cowardice and soothes the Liver. (Yi Jian Zhi)
Its efficacy is similar to that of Lead Oxide (Qiandan), so it is used as a substitute in plasters. If phlegm is knotted in the chest and does not dissipate, take one liang of Mirabilite (Mituoseng), one cup of vinegar, and one cup of water; boil until dry and grind into powder. Take two qian each time, decocted with a small cup of wine and a small cup of water until reduced to one cup; take warm. It is ideal if phlegm and saliva are vomited out after a short while. For wind-intestinal hemorrhoids, use one qian of Verdigris (Tongqing) and one qian of Mirabilite (Mituoseng), with a small amount of Musk (Shexiang); grind into powder and apply with saliva. For bone abscess (also known as Poly-bone sore, which periodically discharges fine bones), caused by the mother engaging in intercourse before one month of pregnancy, absorbing the essence and qi; apply Mirabilite (Mituoseng) powder mixed with Tung Oil paste to the affected area for cure. For blood-wind sores, dissolve Mirabilite (Mituoseng) in Sesame Oil, spread on oiled paper to make a plaster, and apply repeatedly.
[Discussion] Li Shizhen stated that Mirabilite (Mituoseng) is heavy and sinking, acting directly on the Lower Jiao, capable of resolving phlegm, stopping vomiting, and eliminating accumulation. However, he did not realize that Lead is inherently extreme Yin; its downward movement is returning to its origin. Yin failing to move downward and returning to its source is due to Yin deficiency. For instance, chronic dysentery damages Yin qi; fright epilepsy occurs because Yin is insufficient to anchor Yang, leading to pathology from fright and inability to manifest Yang's function, resulting in epilepsy. Similarly, retroflexion of the stomach (Fanwei) is also due to Yin insufficiency preventing downward return, causing Yang to rebel upward. The conditions treated by Tuoseng largely fall within this principle.
Mirabilite (Mituoseng) is only used to treat dark complexion (facial darkness and dullness). Apart from external application, people no longer use it internally nowadays. Generally, it can be applied externally but should not be taken internally. Genuine Mirabilite (Mituoseng) is hard to obtain. The bottom of silver-smelting furnaces is formed by the condensation of Nitre-Copper qi; it can corrode all things. Therefore, it is even more unsuitable for casual use. (Chen Shigong)
[Processing] The furnace bottom is hard and heavy; pieces that appear golden when crushed are superior. Use raw for external application; for internal use, calcine until yellow, then grind finely.