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Lepisma saccharina (Yi Yu)

Pungent in flavor, warm in nature, non-toxic. Primarily treats gynecological masses (abdominal lumps), difficulty in urination, and neck stiffness with dorsal elevation caused by wind-stroke in children; it can be applied by rubbing the affected area. It also treats strangury (dysuria), induces abortion, and when applied topically, eliminates scars from sores. Also known as Bai Yu (White Fish), or one name is [Character: 蠹] (pronounced Tan). Grows in the flat marshes of Xianyang.

Tao Hongjing stated: It is found within clothes but cannot be obtained constantly; it is mostly found in books and can also be used. For treating childhood strangury and retention, rubbing it on the umbilicus and lower abdomen will immediately promote urination. Minister Yuxi et al., according to *Xing Yao Lun*, state: White fish from clothing, when used as an assistant drug, is toxic and promotes diuresis.

*TU JING BEN CAO* states: Yi Yu grows in the flat marshes of Xianyang, and is now found everywhere. It is rare in clothes but common in scrolls. The *Erya* refers to [Character: 蟫] (pronounced Tan, Xun) as Bai Yu. Guo Pu said: The insect hidden in clothes and books, also named [Character: 蠹] (pronounced Bing) Yu, is this species. Duan Chengshi said: Buque Zhang Zhoufeng saw melon seeds on the wall transform into white fish, thus knowing that the statement in *Liezi* about rotten melons transforming into fish is not false. Ancient prescriptions: Primarily treat childhood strangury and retention; take Yi Yu to rub the umbilicus and lower abdomen, and urination will immediately flow. Also combined with eagle droppings and *Bombyx Batryticatus* (Jiang Can) to apply to sores and scars, which will then disappear. People today call it Bi Yu (Wall Fish); folklore says that if Bi Yu enters Taoist scripture boxes and eats immortal characters due to boring, its body will display five colors. If a person obtains and swallows it, they can achieve immortality. In the Tang Dynasty, the youngest son of Zhang Tang was confused by this theory, so he wrote many immortal characters, cut them into pieces, put them in a bottle, caught Bi Yu and threw them in, hoping they would eat the characters but could not escape, resulting in him developing heart disease.

*Qianjin Fang*: Treats sand, stones, or grass debris falling into the eye that cannot be removed. Mix Bai Yu with milk juice and drip into the eye. *Waitai Miyao*: Primarily treats leukoma (corneal opacity). Grind Bai Yu into powder, take a small amount and sprinkle on the leukoma. Sun Simiao suddenly suffered from hemiplegia, with facial paralysis and slurred speech. Take Bai Yu to rub below the ear. Rub the right side when moving left, and the left side when moving right; stop when symmetry is restored. When a person inexplicably passes blood in urine. Put thirty Yi Yu from clothing into the vagina. *Shiyi Xinjing*: Treats pediatric Ke Wu (illness caused by external pathogenic factors or fright). Take ten Bai Yu from books, apply to the nipple, and let the infant suckle until recovery.

*Yanyi* states: Yi Yu is mostly found in old books. In places where things remain undisturbed for a long time, silk fabrics may have them, but not as many as in old paper. Its body has thick powder; if touched by hand, it falls off. It also gnaws on woolen clothes, and its uses are few. Its shape is somewhat like a fish, and its tail is bifurcated. The world uses it to eliminate scars.

Remaining records from Chen Zangqi's Thirty-Six Varieties.