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Bitter, pungent, cold, extremely cold, non-toxic. It treats various diseases, eliminates pathogenic factors of cold and heat, expels accumulations, fixed masses, and lingering癖 (accumulated masses) in the six fu organs, resolves heat accumulation from food and drink retention in the stomach, breaks up retained blood and obstructions, dispels stagnant phlegm causing fullness and痞 (masses), pushes out the old to bring forth the new. It can dissolve seventy-two types of minerals. After refining and taking it, one becomes light-bodied and may attain immortality.

Refined, it is white as silver; its nature can be cold or hot, its action slippery or astringent, its taste pungent, bitter, salty, or sour. It remains unchanged even after being buried in the earth for a thousand years. Those that are greenish-white are superior; those that are yellow harm the body, and those that are red kill. Another name is Xiaoshi Pu (Niter Puxiao). It grows on sunny slopes in valleys with saline water sources in Yizhou. It can be harvested at any time.

It fears Maijujiang (Trollius chinensis). Currently, it is produced in Wenshan Commandery in northern Yizhou, Xichuan, and the borders of Canling County. It grows on mountain cliffs, mostly greenish-white in color, often mixed with black spots. In secular use, this stone should be heated until the juice boils out, resembling Fan Shi (Alum Stone). The *Xian Jing* (Immortal Classic) only states that Xiaoshi (Niter) can dissolve other stones. This text also claims it can dissolve stones, suspecting they must be similar; this can be tested.

[Respectful Note] There are two types of this substance: one has longitudinal grain, the other has diffuse grain (Man Li); there is no difference in their use. The white and soft variety is the sprout of Puxiao (Mirabilite); it is void and soft with weak efficacy. When refined into Xiaoshi (Niter), the yield is low. Using it as a substitute for Xiaoshi results in significantly inferior therapeutic power.

Bitter, pungent, cold, extremely cold, non-toxic. It treats heat accumulation in the five zang organs, gastric distension and obstruction, purges accumulated food retention, pushes out the old to bring forth the new, eliminates pathogenic factors, treats one hundred and twenty diseases within the five zang organs and twelve regular meridians, sudden Shanghan (Cold Damage), severe abdominal heat, relieves vexation, fullness, and Xiao Ke (Wasting-Thirst syndrome), promotes urination, and cauterizes sores. Refined into a paste, long-term consumption lightens the body. It is a divine object of heaven and earth, capable of transforming twelve types of minerals. Another name is Mangxiao (Natrii Sulfas). It grows in the valleys of Yizhou, as well as in Wudu, Longxi, and among the Western Qiang people. It can be harvested at any time.

Yinghuo (Firefly) serves as its guiding herb. It dislikes Kushen (Sophorae Radix) and Kucai (Amaranthus), and fears Nuwan (Polygala japonica). Its therapeutic effects are similar to Puxiao. The *Xian Jing* often uses this substance to digest various minerals. Currently, there are no experts who specifically distinguish between these substances. Recent inquiries suggest they grow on the same mountains, hence Puxiao is called "Xiaoshi Pu," implying they are not the same substance. Previously, someone obtained a substance whose color and texture were largely similar but slightly different from Puxiao; it felt like holding salt snow without freezing. When forcibly burned, it rose with purple-blue smoke and turned to ash, not forming Niter. This was actually made by refining Puxiao. This aligns with Huangfu's statement, but neither has been rigorously verified through experimentation. Further testing and documentation are required. The method for refining Niter is found in the Thirty-Six Waters Formula. Longxi belongs to Qinzhou, located west of Chang'an among the Western Qiang. Currently, it is found in places with saline soil in the mountains of Dangchang.

[Respectful Note] This is Mangxiao (Natrii Sulfas). Puxiao is also known as Xiaoshi Pu. By leaching coarse and impure Puxiao to extract the juice and boiling it down, one refines it into Mangxiao, which is essentially Xiaoshi (Niter). The *Shennong Benjing* lists it under the name Mangxiao; later authors created a separate entry for Mangxiao, which is erroneous.