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(Four Methods of Preparation)

Preparation of Watermelon Nitre (Xigua Xiao)
Select high-quality early-season vines bearing watermelons, one or two in number. Cushion them with rice straw and place them in a dry kitchen. On the day of Start of Winter (Lidong), remove the lid of the melon, scoop out seven-tenths of the pulp inside, leaving three-tenths of the flesh attached to the rind. Based on the size of the melon, add two jin (approx. 1 kg) or one-and-a-half jin of Pi Xiao (Mirabilite/Gypsum, specifically crude sodium sulfate), cover it again, and tie it securely with string. Hang it under an eave in a shady location. When the freezing cold period arrives, the nitre will naturally effloresce through the rind to the outside, appearing frost-like in color. Gently brush it off with a broom, collect it in a dish, wrap it well, and retrieve it every three to five days. In spring, store the remaining nitre from the melon properly. Wait until the next Start of Winter, fill fresh melons with it, add another half jin or one jin of nitre, hang it up again, and collect the effloresced substance from the exterior. Repeat this process twice; the nitre obtained in the intermediate stage is also effective, so no further preparation is needed. It can treat throat lichen (Hou Xuan), throat gan (Hou Gan), and various fire syndromes. When blown onto ulcerated areas, it causes no pain. The portion effloresced from the outer skin is named "Silver Powder Snow" (Yin Fen Xue), and its efficacy is comparable to Zi Xue (Purple Snow).

Preparation of Ren Zhong Huang
Take one large bamboo tube of Mao Bamboo, retaining the nodes at both ends. Drill a round hole in one end. Fill the tube completely with finely powdered Da Fen Cao (Licorice Root, *Glycyrrhiza uralensis*), using as much as necessary. Seal the hole with raw lacquer. Scrape off the outer bamboo skin and drill numerous fine holes throughout the entire surface of the tube. Bury it in a large pit. It is fully prepared after ten years, but can be used after six or seven years. It is capable of treating Jie Du (chancre/toxic sores), rotting of the throat, Ya Gan (noma/gangrenous stomatitis), and macules caused by Shang Han (Cold Damage) fever. It is regarded as a holy medicine for these conditions.

Preparation of Bian Bo Zhi (Juice of Biota Leaves)
Pick tender tips of Bi Ye (Biota Tops, *Platycladi Cacumen*) and soak them once in well water. Immediately retrieve them with water and pound them into a paste in a stone mortar. Take a certain amount of the pounded leaves, mix with a small amount of Bai Fan (Alum, *Alumen*) solution, extract the juice, and collect it in a porcelain vessel. When using, dilute with Bai Fan decoction and gargle in the throat. It can treat all types of fire syndromes with stagnant heat, rotting throat, and rotting gan. Its nature is cool, cooling the blood and moistening dryness, clearing fire from the Liver and Stomach. Moreover, it possesses the qi of pine and cypress, and medical texts value it highly; it should not be neglected.

Preparation of Dan Fan
Use Dan (Bile), specifically from Mackerel (*Scomber japonicus*), the quantity being indefinite. Mix it with Bai Fan (Alum, *Alumen*), place the mixture inside a pig bladder, and hang it in a shady place. In the following year, add more bile and allow it to wind-dry again. Repeat this process three times. For acute emergencies, prepare a decoction to induce vomiting upon administration.