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(Seventy-seven kinds, with two appended)

Yuan Dong recorded in *Shuying Congshuo*: A certain family in Wujiang County possessed a "poison-absorbing stone" (Xidu Shi), shaped like the black Go stones from Yunnan. There were also white ones. When a large swelling or toxin appeared on the body, touching the affected area with the stone would cause it to adhere tightly and not detach. For severe toxins, it would fall off after about a week; for mild toxins, it would fall off after exceeding that time. One should wait for it to detach naturally and must not forcibly remove it. If forcibly removed, the toxin will never be fully absorbed. When it is time for the stone to fall off, prepare a large bowl of human milk, divide it into small bowls, and throw the stone into the milk. The milk will then boil vigorously and surge. Replace with fresh milk, let it boil again, and pour it back into the previous mixture. Once the boiling subsides, the stone remains intact because the absorbed toxins have been washed away by the milk. Otherwise, the stone will surely crack. This stone was obtained from the Atlantic region.

*Lingnan Zaji* records: It originates from islands in the Western Seas, being a stone found in the brains of venomous snakes, as large as a soybean. It can absorb all kinds of swellings and toxins, including carbuncles (Fabei). What is currently sold are often made by locals catching these snakes, mixing soil with snake meat, pounding them into powder, and shaping them like Go stones. These can absorb ordinary swellings and injuries from centipedes and scorpions. Placed on the affected area, they stick firmly and do not move; once the toxin is fully absorbed, they fall off naturally. Soaking them in human milk turns them green, after which they should be discarded far away. If not soaked, they will crack, and their efficacy will fail next time. The true brain stone, when placed on a snake's head, does not move, which indicates authenticity. Zhang Lvyi stated: The poison-absorbing stone is actually mud held in the mouth by snakes during hibernation, spat out beside their burrows after the Awakening of Insects (Jingzhe), which people collect and trade.

Commentary: *Gengxin Yu Xian* refers to it as Turkish stone. He Shizhen Duo in *Bencao Bu* states: The poison-absorbing stone is also called Snake Stone (She Shi), and there are two types; in the Western Seas, a stone grows inside the heads of venomous snakes, the size of a chess piece, capable of absorbing various toxic gases; this is naturally formed. Locals grind the snake stone together with the meat of the same snake and local soil into powder to create stones the size of Go pieces; this is artificially manufactured. The Western Seas use the natural snake stone, while the Atlantic region uses only drug-processed ones. Whenever encountering injuries from snakes, scorpions, centipedes, etc., as well as carbuncles, severe toxins, and all kinds of malignant sores, placing this stone on the affected area causes it to adhere tightly without detaching. It releases only when the toxin is fully absorbed. Care must be taken to prevent dropping or damage; store it wrapped in cotton felt or similar materials. Absorption should last only one or two shichen (2-4 hours); if it does not detach, it should be removed, otherwise the stone may shatter. Upon detachment, immediately soak it in human milk. If human milk is unavailable, cow or goat milk can be used. Soak until the milk slightly turns green, yellow, or black, indicating the toxin has been fully extracted. If no milk is available, warm water can be used, but soaking too long will damage the stone, rendering it unusable. After soaking, wash it clean with clear water, dry it, and store it. However, the milk used for soaking contains toxins and must be buried in a pit dug underground to avoid harming humans or animals. If the affected area has no blood flow, scrape it lightly with a small knife until slight bleeding occurs to ensure adhesion. Alternatively, taking internal detoxifying medicine beforehand before using this stone for absorption yields even better results. To test this stone, place it on the head of a venomous snake; the snake will dare not move. However, it must still be soaked in milk as described above to prevent damage to the stone, as the snake's toxin enters the stone during the brief testing period.

Mr. Ji Xiaolan recorded in *Luoyang Xiaoxia Lu*: A young servant named Yubao, son of an exiled official in Dihua, initially served in the military settlement of Tenanage. Once, he entered a valley chasing a lost sheep and saw a giant snake as thick as a pillar coiled atop a high ridge, basking in the sun. Its scales displayed five vibrant colors, resembling piled brocade. On its crown grew a horn about one chi (approx. 33 cm) long. Flocks of pheasants flew past; the snake opened its mouth and sucked, causing the pheasants at a distance of four or five zhang (approx. 13-16 meters) to fall gracefully, like arrows shot into a target. Realizing his sheep had been swallowed, he fled along a stream back home unseen, terrified nearly to the point of losing his soul. Military officer Wu Tulun explained that this snake is extremely venomous, but its horn can neutralize poison; this is what is known as the poison-absorbing stone. Those who encounter such a snake should carry several jin of realgar (Xionghuang) and burn it upwind, causing the snake to become lethargic and immobile. Taking the horn and sawing it into blocks, when a carbuncle first arises, placing one block on the top of the sore makes it adhere like a magnet attracting iron, impossible to detach. Once the toxic gas is absorbed, it falls off naturally. Soaking it in milk extracts the remaining toxin, allowing reuse. For mild toxins, the milk turns green; for moderate toxins, blue-green or dark; for severe toxins, black-purple. It may require four or five absorptions to completely eliminate the toxin, though sometimes one or two suffice. My elder cousin Maoyuan possessed a poison-absorbing stone, which proved effective in treating carbuncles. Its texture is neither wood nor stone; only now do I realize it is a snake horn. Zhao Xuemin notes: Mr. Ji Xiaolan believed it to be the horn of a large snake, while Lvyi believed it to be mud contained by snakes. I fear both are incorrect. Li Shizhen’s *Bencao Gangmu*, under the entry for Snake Horn (Gu Du Xi), citing *Zhuogeng Lu*, *Songmo Jiwen*, Cao Zhao’s *Ge Gu Lun*, and other texts, only mentions its ability to treat carbuncles and toxins, with no mention of absorbing toxins. *Shuying Congshuo* and *Lingnan Zaji* definitively classify it as a stone, and their detailed and accurate explanations are acceptable, so it is listed in the Mineral Section. Various theories are collected for reference. As for "mud contained by snakes," this is actually Snake Gall (She Huang), which is vastly different and clearly distinct.

It treats all kinds of nameless swellings and toxins, as well as injuries from poisonous insects. Applying the stone for absorption leads to immediate recovery.