《玄霜掌上录》

The so-called "Mysterious Frost" (Xuanshuang) is also known as the "Female Mysterious Frost," the "Jade Nectar," the "Jade Fluid," the "Milk of Earth the Mother," the "Sweet Dew Elixir," the "Ninefold-Turned Yin Elixir," or the "Brewed Cream." Since ancient times, although the immortals took the Golden Elixir (金丹), they did not refine this Yin elixir.

Black lead belongs to water, and the number of water is one. One gives rise to two, two gives rise to three, and three can transform into the ten thousand things. Does this not show that the generation of all things cannot do without Yin-Yang? The so-called Great Elixir is formed through the union of Yin-Yang and of dragon and tiger; once refined, it is called "Proper Yang." But this makes it a solitary Yang that cannot stand on its own, so it must rely on the Yin elixir to complement it, much as one relies on a staircase or a ferry. The number of the Yin elixir follows the numbers of Yin-Yang, and it makes use of nine.

As for moistening the five viscera, irrigating the Huagai (the "Flowery Canopy," a Daoist internal alchemy term for a corresponding region of the body), nourishing the Niwan (the "Muddy Pellet," an internal alchemy term for the head) above, and nourishing the Jing-guang (the "Essence Radiance") below, the Great Medicine, without the aid of the Mysterious Frost, will be slow to take effect even after being taken for a long time. The method of refining the Great Elixir appears in the Qi (《契》), while the method of refining the Yin-source Mysterious Frost comes from the Secret Record (《秘录》), so it is hard for practitioners to know. Now the method for refining the "Yin Elixir, White Snow, Mysterious Frost" will be explained in detail.

Take two jin of top-quality raw black lead and half a jin of mercury. First place the lead in a "Yaozi" and hammer it until it becomes extremely fine and no dust or flakes can be seen. Then pour the mercury into the lead, stir thoroughly, and pour the mixture out, forming lumps about the size of a "Huozi."

When ready to use it, take a porcelain jar coated with oil inside and out, fill it with five sheng of top-quality vinegar, and set it in a stable, convenient room. The work must also be done in a bright, south-facing room and begun when yang energy is at its height, since this is believed to bring the work into accord with the qi (vital energy) of the Dao (the Way). Sink the jar into a pit in the ground so that its mouth is level with the floor. Set the crucible holding the lead and mercury over the mouth of the jar, lay three or four layers of paper on top, and cover it all with a porcelain bowl.

If the work is carried out when yang energy is at its fullest, open it once every seven days. A frost-like substance will have formed on the crucible, hanging down like inverted flakes of snow. Left exposed to the air for a while, it hardens by itself and can be scraped off and collected. If the vinegar in the jar runs low, replace it. Repeat the collecting in this way until one jin of "frost" has been obtained.

Next, put the frost into a porcelain vessel, add sweet rice-water, and grind it slowly with a willow mallet until it resembles a paste of flour. Spread it around the inside of a bowl and steam it in cooked rice. After steaming, grind it again, then rinse it in clean water, let it settle, and drain it. Then pound and rinse it again in clean water and steam it by the same method: five times in cooked rice and four times in so-called "earth rice." When steaming in earth rice, another bowl must also be inverted over the mouth of the bowl. The whole process is repeated nine times.

When the nine rounds are complete, filter and wash the substance in a silver vessel with a bag of cooked silk and clean water, then let it stand for a while. Soak a wad of cotton in clean water and cover the mouth of the vessel with it, then dry it in the sunlight. Scrape off what has formed and grind it fine with a willow mallet. The finished product is said to be the color of spring snow and the texture of fine flour, with a mild, sweet taste; when pinched and held in the mouth, it is said to feel as cool as spring ice.

The book claims that anyone who succeeds in refining this substance can make it into pills the size of parasol-tree seeds with honey. Taking five pills a day for a year is said to make one immune to all illness and free from thirst throughout the summer. After washing the hair, one may mix it with raw oil and apply it to the crown of the head, and in a short time a coolness is said to spread from the head down to the soles of the feet, with effects too numerous to describe. The text adds that, to restore youth in old age by means of the "Great Elixir," the crucial point lies in the circulation of the bodily fluids.

Master Sun's verse says: "Dark White Frost, oh Dark White Frost, you hold first place among the Dragon and Tiger. If the myriad things were not born from yin, then from where would solitary yang draw its nourishment?"

In this passage, "mercury" means quicksilver. "Frost" is the white, frost-like substance obtained by refining lead, mercury, and other materials according to a prescribed method. "Dragon and Tiger" is a common symbolic term in alchemy. The closing verse uses the mutual generation of Yin-Yang to show that isolated yang energy cannot, by itself, nourish the myriad things into being.