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This is the yellow earth found beneath the iron cauldron in the center of the stove. Because it is believed that the stove possesses a spirit, its name is thus euphemistically and obscurely referred to. (Tao Hongjing) Do not mistakenly use ordinary earth from under the stove. The so-called *Fulonggan* (Dragon Liver Earth) is formed by the long-term accumulation of fire qi within the stove over ten years, naturally condensing into something resembling red stone, with a yellow center and an octagonal prismatic shape. After obtaining it, grind it into fine powder and use it after being processed by water levigation. (Lei Xiao)

Note: These two descriptions differ, yet cases like those described by Tao are quite numerous.

It tastes pungent and has a slightly warm nature. It primarily treats cough with rebellious qi, hematemesis (vomiting blood), epistaxis (nosebleed), blood in stool due to intestinal wind, hematuria (blood in urine), seminal emission, as well as metrorrhagia and leukorrhea in women. For pregnant women suffering from epidemic febrile diseases causing fetal unrest, it can facilitate the delivery of the placenta. It also treats nocturnal crying in infants, aphasia due to stroke in adults, mania, sudden fright or evil invasion, sudden enchantment, gu poison, and the qi of various sores, carbuncles, and swelling toxins. (Apply mixed with vinegar.) It possesses the wonderful efficacy of Fire generating Earth; dryness can remove dampness, thus making it a holy medicine for stopping bleeding, especially for treating metrorrhagia and collapse due to deficiency. (Langfeng)

For prolonged hematemesis that does not stop, take 2 qian of *Fulonggan*, mixed with rice decoction to swallow, which will stop immediately. For lower gastrointestinal bleeding, take 3 liang each of *Fulonggan*, *Shudihuang* (Prepared Rehmannia Root), *Baizhu* (Atractylodes Macrocephala Rhizome), *Fuzi* (Prepared Aconite Lateral Root), *Ejiao* (Donkey-hide Gelatin), and *Huangqin* (Scutellaria Root), along with 0.5 jin of earth from the stove, decoct in water and take orally. For female blood leakage, take 0.5 liang of *Fulonggan*, 1 liang each of prepared *Ejiao* and stir-fried *Can Sha* (Silkworm Frass), grind into powder, and take 2-3 qian with wine on an empty stomach, until effectiveness is achieved. For chronic red and white leukorrhea with long-standing sallow complexion and faint, choppy pulses in all six positions, take equal parts of *Fulonggan*, palm ash, and dust from above the beam, stir-fry each until smoke ceases, grind into powder, add small amounts of *Longnao* (Borneol) and *Shexiang* (Musk), take 3 qian per dose, swallowed with warm wine or light vinegar soup. For a duration of one year, peace can be achieved within half a month. For febrile disease during pregnancy, take an amount of *Fulonggan* powder equivalent to a chicken egg, mix with water to swallow, and still apply water-mixed paste to a square-cun area of the umbilicus, reapplying when dry. For stroke with locked jaw, aphasia, mental restlessness and confusion, inability to move limbs voluntarily, abdominal pain and fullness, or apparent death followed by revival, take 5 sheng of *Fulonggan* powder, 8 sheng of water, stir, clarify, and take the liquid. For regurgitation and vomiting of food, take powder made from old stove earth, swallow 3 qian with rice decoction. This formula also treats stomach deficiency. For infant erysipelas, mix powder of old stove earth with rainwater collected from eaves to apply; fresh drawn water is also acceptable, as are egg white or oil. Change when dry. For chronic ulcerative sores, grind fine old earth from inside the stove, add *Huangbai* (Phellodendron Bark), *Huandan* (Lead Monoxide), *Chishizhi* (Red Halloysite), and *Qingfen* (Calomel).

[Discussion] *Fulonggan* is a remedy for regulating the Spleen and Liver, presumably drawing upon the principle of Fire generating Earth to serve as the primary treatment for various conditions. In the human body, only the Spleen and Stomach correspond to this, serving as the master of the Central Earth, while the function is governed by the Liver associated with Wind transformation. However, the meaning of Fire generating Earth, if merely understood as dryness removing dampness, remains superficial and fails to grasp its subtleties. Although the Spleen and Stomach govern the transformation of damp Earth and participate in the vigorous movement akin to Heaven's strength, this is because the true Fire within Water acts as the mother qi. If Earth does not receive the Fire from Water, damp Earth cannot perform its transformations; if Water does not have Earth as its master, Cold Water cannot perform its transformations. When Earth and Water combine their virtues to establish the substance of Earth, they may become mutually constrained. This causes Yin alone to act as the sole messenger, losing the mother qi of Water below and the functional qi of Earth in the middle. Instead of suffering from Wind deficiency leading to Wind disasters, it might instead bully the Earth it overcomes. (This expands upon Qian Zhongyang's theory of using yellow earth to treat convulsions.) Therefore, one must base actions on the principle of Fire generating Earth, allowing Water and Earth to settle in their proper places, and further rely on the virtue of Water and Earth combining, enabling Wood and Earth to utilize each other, thereby preserving the generative transformation of the Central Earth. Thus, the use of yellow earth is not simply to remove dampness arbitrarily, but precisely to use Yang to transform Yin, allowing dampness to transform and move. Once dampness transforms, Blood is generated. Hence, treating blood disorders relies not on astringency and consolidation, but on replenishing the source of generation and transformation, which constitutes solidifying collapse. Extending this logic, metrorrhagia and leukorrhea in women, and seminal emission in men, are also effective. This is not merely using its drying property, but rather transforming Yin to harmonize Yang, thereby calming Wind transformation. When Wind transformation calms, Qi becomes harmonious. Therefore, treating Wind disorders relies not on dispersing and venting, but on benefiting the source of combined transformation, which constitutes quieting Wind. Extending this, mania, gu poison, evil invasion, and sudden enchantment can be cured.

One might ask: Tonifying Earth often uses drying-dampness agents, such as *Baizhu*. How does this herb differ, resulting in such distinct effects? The answer is: Treating blood disorders often avoids *Baizhu* out of fear that its drying nature might injure Yin and exacerbate the condition. This substance indeed uses Yang to transform Yin; it is not a drying-injury agent. Did the ancient sages deliberate carelessly? No.

It should not be used for hematemesis due to Yin deficiency, as it contains fire qi. It should not be used exclusively for severe carbuncles and swelling toxins that are difficult to resolve. (Chen Shigong)

[Processing] Levigate with water twice, then allow to dry.