Library

Stone lotus seeds are so named because they sink into deep water in autumn, becoming hard and black like stones. *Bencao Gangmu* (Compendium of Materia Medica) records another type of stone lotus seed that resembles earthy stones and has a bitter taste, but its identity is unknown.

This refers to red dates dried in the northern regions. Their flesh is thick and oily, making them suitable for medicinal use. When steamed until black, they are called Jiaozao (Gelatinous Dates), which are also used. Southern dates, however, are steamed with sugar and honey, making them sweeter and more moistening; excessive consumption damages the Spleen and stirs up Damp-Heat, rendering them unsuitable for internal medicine. The seeds of the date tree (Zaoren, Semen Ziziphi Spinosae) are better when aged.

The *Materia Medica* states its functions as calming the mind and relieving fullness. "Yan" is pronounced with the level tone, meaning satiety or fullness. *Bencao Gangmu* describes it as opening the appetite, benefiting the Spleen, tonifying deficiency, and enhancing intelligence, which corresponds to the concept of calming the mind and relieving fullness.

*Bencao Gangmu* states: Its nature is warm, flavor sweet and bitter, with a cold and purgative property. "Cold and purgative" refers to its specific characteristic. Generally, it should be soaked in hot water, skin and tips removed, and stir-fried with bran until yellow. However, when treating Wind-Cold Lung diseases, some practitioners use it with the skin and tips intact to exploit its dispersing properties. For promoting blood circulation, Tao Ren (Peach Seed) should be used raw with skin and tips. For moistening dryness and invigorating blood, it should be soaked in water, skin and tips removed, and stir-fried until yellow before use.

In the *Shennong Bencao Jing*, it is named Tielluo (Iron Filings). It primarily treats severe sores and ulcers caused by Wind-Heat, such as carbuncles, and conditions involving crusts and scabies where pathogenic qi stagnates in the skin. "Jia" (crust) is defined in *Shuowen Jiezi* as a dry ulcer; "Suo" (scabies) gets its name from the hard, armor-like appearance. These conditions are externally dry, with pathogens stagnating in the skin, causing unbearable pain and itching. In TCM theory, Metal controls Wood; when Liver Wood is balanced, pathogenic heat clears naturally, hence Tielluo is indicated. The *Qianjin Fang* uses it to treat Erysipelas in children, based on this same principle. Decocted and taken orally, it also treats Edema. This likely works by borrowing the heavy, sinking Qi of iron to restrain Liver Wood, preventing it from overacting on Spleen Earth. When Spleen Earth is not attacked, Water metabolism resolves spontaneously. After recovery, salt intake must still be restricted because salt's moistening nature may cause relapse.

*Bencao Gangmu* follows the *Shennong Bencao Jing* by listing Puxiao (Raw Natrii Sulfas) and Xiaoshi (Nitrums) together, but categorizes Mangxiao (Mirabilite) under Xiaoshi. It claims there are two types of Xiao: Water Xiao and Fire Xiao. Although their form and substance are similar, their nature and Qi differ significantly. Puxiao is Water Xiao; after boiling and refining, those with fine crystalline structures are Mangxiao, and those resembling horse teeth are Yaxiao (Crystal Natrii Sulfas). They are cold in nature and salty in taste. Xiaoshi is Fire Xiao; after refining, it also comes in Mang and Ya forms. It is very warm in nature and pungent and bitter in taste. Since the Tang and Song dynasties, the Mangxiao and Yaxiao used have all been Water Xiao. This is indeed true. Therefore, since the warm and pungent Fire Xiao is no longer used, there is no need to separately classify the commonly used, cold-natured Mangxiao under Xiaoshi, nor should Xiaoshi be called Fire Xiao. *Tangye Bencao* lists Puxiao, Penxiao, and Xiaoshi, describing Puxiao as warm in nature, while Penxiao and Xiaoshi are cold. It further states that "Xiaoshi" is a general term: unrefined is Shengxiao or Puxiao, while fire-refined is Penxiao or Kuxiao. Other authorities consider Puxiao and Mangxiao to be the same substance, differing only in purity, which is correct. However, current pharmacy Puxiao, also known as Pixiao, is used by tanners to treat leather; when refined clean, it becomes Mangxiao and is used medicinally. This is indeed Water Xiao, produced in Suizhou, Henan. Fire Xiao ignites upon contact with fire, also known as Yanxiao, produced in Shouchun. Private trade is now prohibited due to concerns regarding firearms. Regarding the Xiaoshi in the *Shennong Bencao Jing*, its taste, nature, and indications are not vastly different from Puxiao, consistent with Su Song's description. There is also Shengxiao from Sichuan, unboiled, resembling Puxiao but harder. Thus, Xiaoshi might be akin to Ziran Tong (Natural Pyrolusite), which is not easily obtained in large quantities. Moreover, since Mangxiao is available, there is no need to seek Xiaoshi. *Bencao Gangmu*'s discussions are numerous and confusing, unfortunately not fully clarified. The Song Dynasty's *Huimin Heji Ju Fang* contains the Bixue Formula for various heat diseases, using Puxiao, Mangxiao, Yaxiao, and Xiaoshi together, all of which are Water Xiao. Practitioners of Huangdi Neijing and Shennong Bencao Jing should investigate these distinctions carefully and not overlook them.