All things burn when exposed to fire, yet Huawan cloth (fire-washing cloth) and Fengshou wood are unique in that they do not char when burned. Furthermore, Huoyou (fire oil) burns more intensely when it comes into contact with water; Qian Wusu Wang once used this substance.
Dragons shed their bones, snakes shed their skins, elk and deer shed their antlers, crabs shed their claws, and humans replace their teeth; this is the natural transformation of Qi (vital energy).
(Bingzhang) Note: The changes in physical phenomena are often difficult to explain by common sense. For example, sharks transforming into deer, changing from fish to beasts; or field mice transforming into [birds/bats - text implies transformation]. When Qi and Blood decline, hair and beard turn white easily; this serves as an indicator of lifespan. I observed in the biography of Wang Biaozhi in the *Book of Jin* that at the age of twenty, his beard and hair were already completely white. People of the time called him "Wang White-Beard," yet he rose to the rank of Guanglu Dafu (Grand Master of the Palace) and Yi Tong San Si (Official equivalent to the Three Excellencies), dying at the age of seventy-three. This is likely a special endowment and cannot be judged by ordinary standards. Similarly, Du Yanzhou (Du Qi Gong) of the Song Dynasty had completely white hair and beard after the age of forty, living to be eighty years old.
(Bingzhang) Note: Diligent study in youth and excessive labor consume Qi and Blood, leading to premature whitening of hair and beard. This is due to insufficient nutrition, causing pigments to fail to nourish the hair and beard. If the beard and hair are clear, long, and lustrous, as seen in the phrase "childlike face and crane-like hair" (Tongyan Hefa), it is a sign of longevity and wealth, such as in the cases of Wang Biaozhi of the Jin Dynasty and Du Yanzhou of the Song Dynasty.