Library

The *Classic of Materia Medica* (Shennong Bencao Jing) states: "Salty in taste," referring to its meat. People harvest the meat for culinary use, dry it, and transport it to the capital, where northerners regard it as a delicacy. Both the meat and the shell are usable; practitioners should exercise careful judgment in their application. However, both are used to treat eye disorders. The shell is ground and processed by water levigation (shui fei), then applied externally or rubbed on the eyes to treat leukoma (yì zhàng). They are abundant in Dengzhou and Laizhou.

It is frequently used in formulas for pediatric convulsive fever. It is also found in ponds and lakes in Hebei. Those with a diameter of one cun often have a slightly reddish hue. The pearl oyster differs from those produced in Lianzhou; those growing in clear, fast-flowing waters have a bright white luster, while those in turbid or stagnant waters appear dull. Other characteristics remain as described in the Classic.

Qin turtle refers to turtles native to Qin territory (modern Shaanxi). The mountains of Qin contain many old turtles that are exceptionally large and long-lived. Turtle shell is not exclusive to Qin, as it is available everywhere, but the large specimens from Qin are considered superior. Currently, Duoliu and Diaotai in Hebei produce them abundantly; the plastron (guī tǒng) is harvested for treatment and incorporated into various prescriptions. These two types are detailed under their respective entries. Because the turtle is believed to possess spiritual qualities, practitioners use it to tonify the Heart, and this application has proven highly effective.

It treats wind-heat affecting the Heart channel. Fresh specimens are used in medicine because they retain their complete nature and flavor. Once subjected to boiling or fire, they become unsuitable for medicinal use, having been transformed into artifacts. This principle is analogous to the distinction between raw and prepared rhinoceros horn (Xījiǎo).

The turtle is a substance of extreme Yin, hence its scutes number thirty-six. When Yin reaches its extremity, Yang emerges in summer; thus, the *Suwen* states: "Fish causes heat in the middle." Wang Shuhe stated: "Heat generates wind." Consumption of fish can therefore induce wind-heat conditions, a point overlooked by other commentators. While *Ri Hua Zi Bencao* claims "Carp is cool," this view is rejected here in favor of the authority of the *Suwen*. If individuals suffering from wind disorders consume fish, it may lead to endless complications.

Currently, it is called black carp. Daoists consider those with star-like markings on the head to be objects of taboo. Those aware of this belief often refrain from eating it. Furthermore, it may exacerbate chronic diseases and must be avoided. In current medical practice, only specific aspects of its properties are utilized for treating illness.

Its shape somewhat resembles an otter, possessing four feet, with a heavy, sagging abdomen like a pouch, and a body of slight purple hue. Upon dissection, three small crabs, four or five small stones (about the size of a fingernail), and five to seven small fish were found inside. However, it lacks scales and resembles *Lín* (silver-scaled loach) and eel. It is currently not in use.